Science.gov

Sample records for calibration laboratory sources

  1. Radiometric sources for the Los Alamos National Laboratory calibration Laboratory

    SciTech Connect

    Maier, W.B. II; Holland, R.; Bender, S.; Byrd, D.; Michaud, F.D.; Moore, S.; O`Brian, T.R.

    1994-07-01

    Los Alamos is developing a laboratory that will support state of the art calibration of moderate-aperture instrumentation (< 40 cm diameter) having high spatial and thermal resolution. Highly accurate calibration in the reflected solar and thermal infrared spectral regions are required for newly developed instrumentation. Radiometric calibration of the instrumentation requires well-characterized, extensive sources of radiation from 0.45 to 12 {mu}m. For wavelengths above 2.5 {mu}m, blackbodies having temperature control and radiometric uniformity to within 100 mK are being designed and will be radiometrically characterized at the National Institute of Standards and Technology (NIST). For the spectral range 0.45--2.5 {mu}m, a ``whitebody`` integrating sphere equipped with tungsten-halogen lamps and enclosed inside a vacuum shroud will be used; this vacuum-compatible extensive standard diffuse source utilizes well-known technology and will be characterized at NIST`s existing facilities. Characterization of instrumental contrast performance for wavelengths, {lambda}, beyond 2.5 {mu}m will utilize a recently designed absolute variable-contrast IR radiometric calibrator, and preliminary data indicate that this calibrator will perform satisfactorily. Conceptual design and status of these extensive broad-band sources and of a monochromatic source to be used for spectral calibrations will be presented.

  2. NVLAP calibration laboratory program

    SciTech Connect

    Cigler, J.L.

    1993-12-31

    This paper presents an overview of the progress up to April 1993 in the development of the Calibration Laboratories Accreditation Program within the framework of the National Voluntary Laboratory Accreditation Program (NVLAP) at the National Institute of Standards and Technology (NIST).

  3. Calibrated vapor generator source

    DOEpatents

    Davies, J.P.; Larson, R.A.; Goodrich, L.D.; Hall, H.J.; Stoddard, B.D.; Davis, S.G.; Kaser, T.G.; Conrad, F.J.

    1995-09-26

    A portable vapor generator is disclosed that can provide a controlled source of chemical vapors, such as, narcotic or explosive vapors. This source can be used to test and calibrate various types of vapor detection systems by providing a known amount of vapors to the system. The vapor generator is calibrated using a reference ion mobility spectrometer. A method of providing this vapor is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the vapor pressure of the material) to control the concentration of vapors in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of vapors at the outlet. 10 figs.

  4. Calibrated vapor generator source

    DOEpatents

    Davies, John P.; Larson, Ronald A.; Goodrich, Lorenzo D.; Hall, Harold J.; Stoddard, Billy D.; Davis, Sean G.; Kaser, Timothy G.; Conrad, Frank J.

    1995-01-01

    A portable vapor generator is disclosed that can provide a controlled source of chemical vapors, such as, narcotic or explosive vapors. This source can be used to test and calibrate various types of vapor detection systems by providing a known amount of vapors to the system. The vapor generator is calibrated using a reference ion mobility spectrometer. A method of providing this vapor is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the vapor pressure of the material) to control the concentration of vapors in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of vapors at the outlet.

  5. Design, fabrication, and calibration of curved integral coils for measuring transfer function, uniformity, and effective length of LBL ALS (Lawrence Berkeley Laboratory Advanced Light Source) Booster Dipole Magnets

    SciTech Connect

    Green, M.I.; Nelson, D.; Marks, S.; Gee, B.; Wong, W.; Meneghetti, J.

    1989-03-01

    A matched pair of curved integral coils has been designed, fabricated and calibrated at Lawrence Berkeley Laboratory for measuring Advanced Light Source (ALS) Booster Dipole Magnets. Distinctive fabrication and calibration techniques are described. The use of multifilar magnet wire in fabrication integral search coils is described. Procedures used and results of AC and DC measurements of transfer function, effective length and uniformity of the prototype booster dipole magnet are presented in companion papers. 8 refs.

  6. Cobalt source calibration

    SciTech Connect

    Rizvi, H.M.

    1999-12-03

    The data obtained from these tests determine the dose rate of the two cobalt sources in SRTC. Building 774-A houses one of these sources while the other resides in room C-067 of Building 773-A. The data from this experiment shows the following: (1) The dose rate of the No.2 cobalt source in Building 774-A measured 1.073 x 10{sup 5} rad/h (June 17, 1999). The dose rate of the Shepherd Model 109 Gamma cobalt source in Building 773-A measured 9.27 x 10{sup 5} rad/h (June 25, 1999). These rates come from placing the graduated cylinder containing the dosimeter solution in the center of the irradiation chamber. (2) Two calibration tests in the 774-A source placed the graduated cylinder with the dosimeter solution approximately 1.5 inches off center in the axial direction. This movement of the sample reduced the measured dose rate 0.92% from 1.083 x 10{sup 5} rad/h to 1.073 x 10{sup 5} rad/h. and (3) A similar test in the cobalt source in 773-A placed the graduated cylinder approximately 2.0 inches off center in the axial direction. This change in position reduced the measured dose rate by 10.34% from 1.036 x 10{sup 6} to 9.27 x 10{sup 5}. This testing used chemical dosimetry to measure the dose rate of a radioactive source. In this method, one determines the dose by the chemical change that takes place in the dosimeter. For this calibration experiment, the author used a Fricke (ferrous ammonium sulfate) dosimeter. This solution works well for dose rates to 10{sup 7} rad/h. During irradiation of the Fricke dosimeter solution the Fe{sup 2+} ions ionize to Fe{sup 3+}. When this occurs, the solution acquires a slightly darker tint (not visible to the human eye). To determine the magnitude of the change in Fe ions, one places the solution in an UV-VIS Spectrophotometer. The UV-VIS Spectrophotometer measures the absorbency of the solution. Dividing the absorbency by the total time (in minutes) of exposure yields the dose rate.

  7. Cherenkov Source for PMT Calibrations

    NASA Astrophysics Data System (ADS)

    Kaptanoglu, Tanner; SNO+ at UC Berkeley Collaboration

    2013-10-01

    My research is focused on building a deployable source for PMT calibrations in the SNO+ detector. I work for the SNO+ group at UC Berkeley headed by Gabriel Orebi Gann. SNO+ is an addition to the SNO project, and its main goal is to search for neutrinoless double beta decay. The detector will be monitored by over 9500 photomultiplier tubes (PMTs). In order to characterize the PMTs, several calibration sources are being constructed. One of which, the Cherenkov Source, will provide a well-understood source of non-isotropic light for calibrating the detector response. My goal is to design and construct multiple aspects of the Cherenkov Source. However, there are multiple questions that arose with its design. How do we keep the scintillation light inside the Cherenkov source so it does not contaminate calibration? How do we properly build the Cherenkov source: a hollow acrylic sphere with a neck? Can we maintain a clean source throughout these processes? These are some of the problems I have been working on, and will continue to work on, until the deployment of the source. Additionally, I have worked to accurately simulate the physics inside the source, mainly the energy deposition of alphas.

  8. NVLAP activities at Department of Defense calibration laboratories

    SciTech Connect

    Schaeffer, D.M.

    1993-12-31

    There are 367 active radiological instrument calibration laboratories within the U.S. Department of Defense (DoD). Each of the four services in DoD manages, operates, and certifies the technical proficiency and competency of those laboratories under their cognizance. Each service has designated secondary calibration laboratories to trace all calibration source standards to the National Institute of Standards and Technology. Individual service radiological calibration programs and capabilities, present and future, are described, as well as the measurement quality assurance (MQA) processes for their traceability. National Voluntary Laboratory Accreditation Program (NVLAP) programs for dosimetry systems are briefly summarized. Planned NVLAP accreditation of secondary laboratories is discussed in the context of current technical challenges and future efforts.

  9. HPS instrument calibration laboratory accreditation program

    SciTech Connect

    Masse, F.X; Eisenhower, E.H.; Swinth, K.L.

    1993-12-31

    The purpose of this paper is to provide an accurate overview of the development and structure of the program established by the Health Physics Society (HPS) for accrediting instrument calibration laboratories relative to their ability to accurately calibrate portable health physics instrumentation. The purpose of the program is to provide radiation protection professionals more meaningful direct and indirect access to the National Institute of Standards and Technology (NIST) national standards, thus introducing a means for improving the uniformity, accuracy, and quality of ionizing radiation field measurements. The process is designed to recognize and document the continuing capability of each accredited laboratory to accurately perform instrument calibration. There is no intent to monitor the laboratory to the extent that each calibration can be guaranteed by the program; this responsibility rests solely with the accredited laboratory.

  10. Laboratory calibration and characterization of video cameras

    NASA Technical Reports Server (NTRS)

    Burner, A. W.; Snow, W. L.; Shortis, M. R.; Goad, W. K.

    1990-01-01

    Some techniques for laboratory calibration and characterization of video cameras used with frame grabber boards are presented. A laser-illuminated displaced reticle technique (with camera lens removed) is used to determine the camera/grabber effective horizontal and vertical pixel spacing as well as the angle of nonperpendicularity of the axes. The principal point of autocollimation and point of symmetry are found by illuminating the camera with an unexpanded laser beam, either aligned with the sensor or lens. Lens distortion and the principal distance are determined from images of a calibration plate suitably aligned with the camera. Calibration and characterization results for several video cameras are presented. Differences between these laboratory techniques and test range and plumb line calibration are noted.

  11. Laboratory Calibration and Characterization of Video Cameras

    NASA Technical Reports Server (NTRS)

    Burner, A. W.; Snow, W. L.; Shortis, M. R.; Goad, W. K.

    1989-01-01

    Some techniques for laboratory calibration and characterization of video cameras used with frame grabber boards are presented. A laser-illuminated displaced reticle technique (with camera lens removed) is used to determine the camera/grabber effective horizontal and vertical pixel spacing as well as the angle of non-perpendicularity of the axes. The principal point of autocollimation and point of symmetry are found by illuminating the camera with an unexpanded laser beam, either aligned with the sensor or lens. Lens distortion and the principal distance are determined from images of a calibration plate suitable aligned with the camera. Calibration and characterization results for several video cameras are presented. Differences between these laboratory techniques and test range and plumb line calibration are noted.

  12. Multigamma-ray calibration sources

    SciTech Connect

    Meyer, R.A.; Massey, T.N.

    1983-05-01

    We have calibrated a self-consistent set of multigamma-ray standards using the automated multi-spectrometry ..gamma..-ray counting facility at LLNL's Nuclear Chemistry Division. Pure sources of long-lived activity were produced by mass separation and/or chemical purification. The sources were counted individually and in combination on several different calibrated spectrometer systems. These systems utilize various detectors ranging from small (x-ray) detectors to large volume high-purity Ge detectors. This has allowed the use of the most ideal individual detector-efficiency characteristics for the determination of the relative ..gamma..-ray intensities. Precise energy measurements, reported earlier (Meyer, 1976) have been performed by an independent method. Both the energy and ..gamma..-ray-emission probabilities determined compare well with independently established values such as the recent ICRM intercomparison of /sup 152/Eu. We discuss our investigations aimed at resolving the shape of the efficiency response function up to 10 MeV for large volume Ge(Li) and high-purity Ge detectors. Recent results on the ..gamma..-ray-emission probabilities per decay for /sup 149/Gd and /sup 168/Tm multigamma-ray sources are discussed. For /sup 168/Tm, we deduce a 0.01% ..beta../sup -/ branch to the 87.73-keV level in /sup 168/Yb rather than the previous value which was a factor of 200 greater. In addition, we describe current cooperative efforts aimed at establishing a consistent set of data for short-lived fission products. Included are recent measurements on the bromine fission products with ..gamma.. rays up to 7 MeV.

  13. RADCAL Operations Manual Radiation Calibration Laboratory Protocol

    SciTech Connect

    Bogard, J.S.

    1998-12-01

    The Life Sciences Division (LSD) of Oak Ridge National Laboratory (ORNL) has a long record of radiation dosimetry research, primarily using the Health Physics Research Reactor (HPRR) and the Radiation Calibration Laboratory (RADCAL) in its Dosimetry Applications Research (DOSAR) Program. These facilities have been used by a broad segment of the research community to perform a variety of experiments in areas including, but not limited to, radiobiology, radiation dosimeter and instrumentation development and calibration, and the testing of materials in a variety of radiation environments. Operations of the HPRR were terminated in 1987 and the reactor was moved to storage at the Oak Ridge Y-12 Plant; however, RADCAL will continue to be operated in accordance with the guidelines of the National Institute of Standards and Technology (NIST) Secondary Calibration Laboratory program and will meet all requirements for testing dosimeters under the National Voluntary Laboratory Accreditation Program (NVLAP). This manual is to serve as the primary instruction and operation manual for the Oak Ridge National Laboratory's RADCAL facility. Its purpose is to (1) provide operating protocols for the RADCAL facility, (2) outline the organizational structure, (3) define the Quality Assurance Action Plan, and (4) describe all the procedures, operations, and responsibilities for the safe and proper operation of all routine aspects of the calibration facility.

  14. Radiometric validation of NASA's Ames Research Center's Sensor Calibration Laboratory.

    PubMed

    Brown, Steven W; Johnson, B Carol; Biggar, Stuart F; Zalewski, Edward F; Cooper, John; Hajek, Pavel; Hildum, Edward; Grant, Patrick; Barnes, Robert A; Butler, James J

    2005-10-20

    The National Aeronautics and Space Administration's (NASA's) Ames Research Center's Airborne Sensor Facility (ASF) is responsible for the calibration of several airborne Earth-viewing sensor systems in support of NASA Earth Observing System (EOS) investigations. The primary artifact used to calibrate these sensors in the reflective solar region from 400 to 2500 nm is a lamp-illuminated integrating sphere source. In September 1999, a measurement comparison was made at the Ames ASF Sensor Calibration Facility to validate the radiometric scale, establish the uncertainties assigned to the radiance of this source, and examine its day-to-day repeatability. The comparison was one of a series of validation activities overseen by the EOS Calibration Program to ensure the radiometric calibration accuracy of sensors used in long-term, global, remote-sensing studies. Results of the comparison, including an evaluation of the Ames Sensor Calibration Laboratory (SCL) measurement procedures and assigned radiometric uncertainties, provide a validation of their radiometric scale at the time of the comparison. Additionally, the maintenance of the radiance scale was evaluated by use of independent, long-term, multiyear radiance validation measurements of the Ames sphere source. This series of measurements provided an independent assessment of the radiance values assigned to integrating sphere sources by the Ames SCF. Together, the measurements validate the SCF radiometric scale and assigned uncertainties over the time period from September 1999 through July 2003.

  15. Radiometric validation of NASA's Ames Research Center's Sensor Calibration Laboratory

    SciTech Connect

    Brown, Steven W.; Johnson, B. Carol; Biggar, Stuart F.; Zalewski, Edward F.; Cooper, John; Hajek, Pavel; Hildum, Edward; Grant, Patrick; Barnes, Robert A.; Butler, James J

    2005-10-20

    The National Aeronautics and Space Administration's (NASA's) Ames Research Center's Airborne Sensor Facility (ASF) is responsible for the calibration of several airborne Earth-viewing sensor systems in support of NASA Earth Observing System (EOS) investigations. The primary artifact used to calibrate these sensors in the reflective solar region from 400 to 2500 nm is a lamp-illuminated integrating sphere source. In September 1999, a measurement comparison was made at the Ames ASF Sensor Calibration Facility to validate the radiometric scale, establish the uncertainties assigned to the radiance of this source, and examine its day-to-day repeatability. The comparison was one of a series of validation activities overseen by the EOS Calibration Program to ensure the radiometric calibration accuracy of sensors used in long-term, global, remote-sensing studies. Results of the comparison, including an evaluation of the Ames Sensor Calibration Laboratory (SCL) measurement procedures and assigned radiometric uncertainties, provide a validation of their radiometric scale at the time of the comparison. Additionally, the maintenance of the radiance scale was evaluated by use of independent, long-term, multiyear radiance validation measurements of the Ames sphere source. This series of measurements provided an independent assessment of the radiance values assigned to integrating sphere sources by the Ames SCF. Together, the measurements validate the SCF radiometric scale and assigned uncertainties over the time period from September 1999 through July 2003.

  16. Intercomparison of Laboratory Radiance Calibration Standards

    NASA Technical Reports Server (NTRS)

    Pavri, Betina; Chrien, Tom; Green, Robert; Williams, Orlesa

    2000-01-01

    Several standards for radiometric calibration were measured repeatedly with a spectroradiometer in order to understand how they compared in accuracy and stability. The tested radiance standards included a NIST 1000 W bulb and halon panel, two calibrated and stabilized integrating spheres, and a cavity blackbody. Results indicate good agreement between the blackbody and 1000 W bulb/spectralon panel, If these two radiance sources are assumed correct, then the integrating spheres did not conform. to their manufacturer-reported radiances in several regions of the spectrum. More detailed measurements am underway to investigate the discrepancy.

  17. Spectrally and Radiometrically Stable, Wideband, Onboard Calibration Source

    NASA Technical Reports Server (NTRS)

    Coles, James B.; Richardson, Brandon S.; Eastwood, Michael L.; Sarture, Charles M.; Quetin, Gregory R.; Porter, Michael D.; Green, Robert O.; Nolte, Scott H.; Hernandez, Marco A.; Knoll, Linley A.

    2013-01-01

    The Onboard Calibration (OBC) source incorporates a medical/scientific-grade halogen source with a precisely designed fiber coupling system, and a fiber-based intensity-monitoring feedback loop that results in radiometric and spectral stabilities to within less than 0.3 percent over a 15-hour period. The airborne imaging spectrometer systems developed at the Jet Propulsion Laboratory incorporate OBC sources to provide auxiliary in-use system calibration data. The use of the OBC source will provide a significant increase in the quantitative accuracy, reliability, and resulting utility of the spectral data collected from current and future imaging spectrometer instruments.

  18. Source calibrations and SDC calorimeter requirements

    SciTech Connect

    Green, D.

    1992-10-01

    Several studies of the problem of calibration of the SDC calorimeter exist. In this note the attempt is made to give a connected account of the requirements on the source calibration from the point of view of the desired, and acceptable, constant term induced in the EM resolution. It is assumed that a ``local`` calibration resulting from exposing each tower to a beam of electrons is not feasible. It is further assumed that an ``in situ`` calibration is either not yet performed, or is unavailable due to tracking alignment problems or high luminosity operation rendering tracking inoperative. Therefore, the assumptions used are rather conservative. In this scenario, each scintillator plate of each tower is exposed to a moving radioactive source. That reading is used to ``mask`` an optical ``cookie`` in a grey code chosen so as to make the response uniform. The source is assumed to be the sole calibration of the tower. Therefore, the phrase ``global`` calibration of towers by movable radioactive sources is adopted.

  19. Source calibrations and SDC calorimeter requirements

    SciTech Connect

    Green, D.

    1992-10-01

    Several studies of the problem of calibration of the SDC calorimeter exist. In this note the attempt is made to give a connected account of the requirements on the source calibration from the point of view of the desired, and acceptable, constant term induced in the EM resolution. It is assumed that a local'' calibration resulting from exposing each tower to a beam of electrons is not feasible. It is further assumed that an in situ'' calibration is either not yet performed, or is unavailable due to tracking alignment problems or high luminosity operation rendering tracking inoperative. Therefore, the assumptions used are rather conservative. In this scenario, each scintillator plate of each tower is exposed to a moving radioactive source. That reading is used to mask'' an optical cookie'' in a grey code chosen so as to make the response uniform. The source is assumed to be the sole calibration of the tower. Therefore, the phrase global'' calibration of towers by movable radioactive sources is adopted.

  20. NIST digitally synthesized power calibration source

    NASA Astrophysics Data System (ADS)

    Oldham, N. M.; Laug, O. B.; Waltrip, B. C.; Palm, R. H.

    1990-08-01

    A digitally-synthesized source of phantom power for calibration electrical power and energy meters is described. Independent sources of voltage, current, and phase angle are programmable between 0-240 volts, 0-5 amps, and 0-360 degrees, respectively. The uncertainty of the active and reactive power is estimated to be within +/- 100 ppm of the full scale apparent power (volt-amps).

  1. Design, manufacture, and calibration of infrared radiometric blackbody sources

    SciTech Connect

    Byrd, D.A.; Michaud, F.D.; Bender, S.C.

    1996-04-01

    A Radiometric Calibration Station (RCS) is being assembled at the Los Alamos National Laboratories (LANL) which will allow for calibration of sensors with detector arrays having spectral capability from about 0.4-15 {mu}m. The configuration of the LANL RCS. Two blackbody sources have been designed to cover the spectral range from about 3-15 {mu}m, operating at temperatures ranging from about 180-350 K within a vacuum environment. The sources are designed to present a uniform spectral radiance over a large area to the sensor unit under test. The thermal uniformity requirement of the blackbody cavities has been one of the key factors of the design, requiring less than 50 mK variation over the entire blackbody surface to attain effective emissivity values of about 0.999. Once the two units are built and verified to the level of about 100 mK at LANL, they will be sent to the National Institute of Standards and Technology (NIST), where at least a factor of two improvement will be calibrated into the blackbody control system. The physical size of these assemblies will require modifications of the existing NIST Low Background Infrared (LBIR) Facility. LANL has constructed a bolt-on addition to the LBIR facility that will allow calibration of our large aperture sources. Methodology for attaining the two blackbody sources at calibrated levels of performance equivalent to present state of the art will be explained in the following.

  2. Source geometry factors for HDR 192Ir brachytherapy secondary standard well-type ionization chamber calibrations

    NASA Astrophysics Data System (ADS)

    Shipley, D. R.; Sander, T.; Nutbrown, R. F.

    2015-03-01

    Well-type ionization chambers are used for measuring the source strength of radioactive brachytherapy sources before clinical use. Initially, the well chambers are calibrated against a suitable national standard. For high dose rate (HDR) 192Ir, this calibration is usually a two-step process. Firstly, the calibration source is traceably calibrated against an air kerma primary standard in terms of either reference air kerma rate or air kerma strength. The calibrated 192Ir source is then used to calibrate the secondary standard well-type ionization chamber. Calibration laboratories are usually only equipped with one type of HDR 192Ir source. If the clinical source type is different from that used for the calibration of the well chamber at the standards laboratory, a source geometry factor, ksg, is required to correct the calibration coefficient for any change of the well chamber response due to geometric differences between the sources. In this work we present source geometry factors for six different HDR 192Ir brachytherapy sources which have been determined using Monte Carlo techniques for a specific ionization chamber, the Standard Imaging HDR 1000 Plus well chamber with a type 70010 HDR iridium source holder. The calculated correction factors were normalized to the old and new type of calibration source used at the National Physical Laboratory. With the old Nucletron microSelectron-v1 (classic) HDR 192Ir calibration source, ksg was found to be in the range 0.983 to 0.999 and with the new Isodose Control HDR 192Ir Flexisource ksg was found to be in the range 0.987 to 1.004 with a relative uncertainty of 0.4% (k = 2). Source geometry factors for different combinations of calibration sources, clinical sources, well chambers and associated source holders, can be calculated with the formalism discussed in this paper.

  3. The Mars Science Laboratory APXS calibration target: Comparison of Martian measurements with the terrestrial calibration

    NASA Astrophysics Data System (ADS)

    Campbell, J. L.; King, P. L.; Burkemper, L.; Berger, J. A.; Gellert, R.; Boyd, N. I.; Perrett, G. M.; Pradler, I.; Thompson, L.; Edgett, K. S.; Yingst, R. A.

    2014-03-01

    The Mars Science Laboratory Curiosity rover carries a basalt calibration target for monitoring the performance of the alpha particle X-ray spectrometer. The spectrum acquired on Sol 34 shows increased contributions from Mg, S, Cl and Fe relative to laboratory spectra recorded before launch. Mars Hand Lens Imager images confirm changes in the appearance of the surface. Spectra taken on Sols 179 and 411 indicate some loss of the deposited material. The observations suggest deposition of a surface film likely consisting of dust mobilized by impingement of the sky crane's terminal descent engine plumes with surface fines during Curiosity's landing. New APXS software has been used to model the thin film that coated the calibration target on landing. The results suggest that a film of about 100 nm thickness, and containing predominantly MgO, Fe2O3, SO3, Cl and Na2O could give rise to the observed spectral changes. If this film is also present on the alpha particle sources within the APXS, then its effect is negligible and the terrestrial calibration remains appropriate.

  4. Noise Source for Calibrating a Microwave Polarimeter

    NASA Technical Reports Server (NTRS)

    Piepmeier, Jeffrey R.; Kim, Edward J.

    2006-01-01

    A correlated-noise source has been developed for use in calibrating an airborne or spaceborne Earth-observing correlation microwave polarimeter that operates in a in a pass band that includes a nominal frequency of 10.7 GHz. Deviations from ideal behavior of the hardware of correlation polarimeters are such as to decorrelate the signals measured by such an instrument. A correlated-noise source provides known input signals, measurements of which can be processed to estimate and correct for the decorrelation effect.

  5. Calibration of multiple LDR brachytherapy sources

    SciTech Connect

    DeWerd, Larry A.; Micka, John A.; Holmes, Shannon M.; Bohm, Tim D.

    2006-10-15

    A trend is underway toward the use of prepackaged low dose rate brachytherapy sources, which come in the form of strands, coiled line sources, preloaded needles, and sterile cartridge packs. Since the medical physicist is responsible for verification of source strength prior to patient treatment, development of prepackaged source strength verification methods is needed. Existing guidelines are reviewed to establish the situation that medical physicists find with respect to prepackaged sources. This investigation presents an experimental evaluation of the effect of some of these multiseed geometries on source strength measurements. Multiseed strands and coils, whether {sup 125}I, {sup 103}Pd, or {sup 192}Ir can be measured in a chamber with a long, sensitive axial length with a uniform response. Sterile seed cartridge packs can also be measured but require a correction factor to be applied. Sources in needles, however, cannot be measured in the needle since there is too great a variation in needle composition and needle tolerance thickness. Removing these seeds from the needle into a sterile measurement insert, which maintains sterility is a practical source strength verification method, similar to those done for multiple seed configurations in a well chamber with adequate axial uniformity. Values are compared with individual air kerma strength calibrations, and correction factors, are presented where needed. In each case, care must be taken to maintain sterility as multiple seeds are measured in well chamber inserts.

  6. High-dose secondary calibration laboratory accreditation program

    SciTech Connect

    Humphreys, J.C.

    1993-12-31

    There is a need for high-dose secondary calibration laboratories to serve the multi-billion dollar radiation processing industry. This need is driven by the desires of industry for less costly calibrations and faster calibration-cycle response time. Services needed include calibration irradiations of routine processing dosimeters and the supply of reference standard transfer dosimeters for irradiation in the production processing facility. In order to provide measurement quality assurance and to demonstrate consistency with national standards, the high-dose secondary laboratories would be accredited by means of an expansion of an existing National Voluntary Laboratory Accreditation Program. A laboratory performance criteria document is under development to implement the new program.

  7. 21 CFR 892.1400 - Nuclear sealed calibration source.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nuclear sealed calibration source. 892.1400... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1400 Nuclear sealed calibration source. (a) Identification. A nuclear sealed calibration source is a device that consists of an...

  8. 21 CFR 892.1400 - Nuclear sealed calibration source.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nuclear sealed calibration source. 892.1400... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1400 Nuclear sealed calibration source. (a) Identification. A nuclear sealed calibration source is a device that consists of an...

  9. 21 CFR 892.1400 - Nuclear sealed calibration source.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nuclear sealed calibration source. 892.1400... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1400 Nuclear sealed calibration source. (a) Identification. A nuclear sealed calibration source is a device that consists of an...

  10. 21 CFR 892.1400 - Nuclear sealed calibration source.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nuclear sealed calibration source. 892.1400... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1400 Nuclear sealed calibration source. (a) Identification. A nuclear sealed calibration source is a device that consists of an...

  11. 21 CFR 892.1400 - Nuclear sealed calibration source.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nuclear sealed calibration source. 892.1400... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1400 Nuclear sealed calibration source. (a) Identification. A nuclear sealed calibration source is a device that consists of an...

  12. Secondary calibration laboratory for ionizing radiation laboratory accreitation program National Institute of Standards and Technology National Voluntary Laboratory Accreditation Program

    SciTech Connect

    Martin, P.R.

    1993-12-31

    This paper presents an overview of the procedures and requirements for accreditation under the Secondary Calibration Laboratory for Ionizing Radiation Program (SCLIR LAP). The requirements for a quality system, proficiency testing and the onsite assessment are discussed. The purpose of the accreditation program is to establish a network of secondary calibration laboratories that can provide calibrations traceable to the primary national standards.

  13. The Los Alamos Calibration Laboratory for multi-spectral and thermal imaging radiometer systems

    SciTech Connect

    Bender, S.; Maier, W.B. II; Byrd, D.; Holland, R.; Michaud, F.D.; Moore, S.; Luettgen, A.; Weber, P.

    1994-06-01

    Los Alamos National Laboratory is currently constructing a calibration laboratory to support the radiometric calibration of remote earth sensing instrumentation. This laboratory will consist of a calibration station contained within a vacuum chamber whose output interface plane will provide a radiometrically characterized collimated optical beam of 16in. diameter. This output beam is fed to a thermal vacuum chamber where sensors under test are to be housed. The station will contain reference sources suitable for calibration of detectors from the visible and near infrared (VIS/NIR) to the thermal infrared. Design goals for these sources include absolute radiometric accuracies of better than 1% (3{sigma}) for the thermal infrared up to 14 {mu}m and VIS/NIR wavelengths up to 0.9 {mu}m. For wavelengths between 0.9 {mu}m and 2.5 {mu}m, absolute accuracies of better than 3% are anticipated. Significant additional features of the calibration station design include: NIST support in the design and calibration of the radiometric sources, spectral characterization of the blackbody references, implementation of a vacuum compatible whitebody (integrating sphere) source, infrared resolution targets of variable contrast, and use of a scan mirror to duplicate target velocity vectors. This paper will provide an overview, description of the intended calibration station capability with further details provided in a companion paper also contained in these proceedings.

  14. Comparison of Meteorological Service Calibration Laboratories in Southeastern Europe

    NASA Astrophysics Data System (ADS)

    Groselj, D.; Bojkovski, J.

    2012-09-01

    Interlaboratory comparisons serve as tools for assessment of measurement results performed by calibration laboratories in the relevant field of measurement. They are effective means to demonstrate technical competence of the participant and are used as a technical base for accreditation. However, in the network of meteorological services calibration laboratories, comparisons among laboratories are still rare. Some laboratories are still not evaluating measurement uncertainty, thus causing problems when comparing meteorological data from different countries. The Environmental Agency of the Republic of Slovenia (EARS), serving in the frame of the World Meteorological Organization as a Regional Instrument Centre, has organized a round-robin comparison of calibration laboratories of meteorological services in the southeastern part of Europe using instruments for temperature, relative humidity, and barometric pressure. Each participant laboratory had to calibrate a set of instruments at defined calibration points, to evaluate the measurement uncertainty (if possible), and to report the results. EARS RIC invited the National Hydrometeorological Services in the southeastern part of Europe to take part in the intercomparison. In addition, the Laboratory of Metrology and Quality (MIRS/UL-FE/LMK), which holds the Slovenian national standard for temperature and relative humidity, was also invited to participate in the comparison and in the data analysis. Results from MIRS/UL-FE/LMK and EARS were used to calculate the temperature and humidity comparison reference values, while the EARS results were taken as reference values for barometric pressure.

  15. Immediate needs for MQA testing at state secondary calibration laboratories

    SciTech Connect

    Cline, R.

    1993-12-31

    The Calibration Laboratory attempts to provide services that satisfy the needs and requests for a variety of customers. New needs and requests have resulted in calibration of instrumentation outside the original laboratory designs. These tasks require several changes at the laboratory and a need for new support services, especially measurement quality assurance (MQA). The MQA tests are gamma (Cs-137) below 0.5 mrem (5{mu}Sv) per hour and x-ray kVp. Modification to the current gamma (Cs-137) MQA test is recommended because lower intensity fields are commonly measured.

  16. 1991 Yearly calibration of Pacific Northwest Laboratory's gross gamma-ray borehole geophysical logging system

    SciTech Connect

    Arthur, R.J.

    1991-08-01

    This report describes the 1991 yearly calibration of a gross gamma-ray geophysical pulse logging system owned by the US Department of Energy (DOE) and operated by the Pacific Northwest Laboratory. The calibration was conducted to permit the continued use of this system for geologic and hydrologic studies associated with remedial investigations at the Hanford Site. Primary calibrations to equivalent uranium units were conducted in DOE borehole model standards that reside on the Hanford Site. The calibrations were performed in borehole models SBL/SBH and SBA/SBB, which contain low-equivalent uranium concentrations. Correlations were established based on two similar approaches for relating observed count rate in before- and after-logging field calibrations to equivalent uranium concentrations. A new field source (Ra-20S-82) was fabricated to replace the old source (Ra-20S-204), whose activity led to variable field calibration results previously caused by a nonfixed geometry. A cross-calibration study was performed to compare the operation of the new source relative to the old source. A digitally based collection/recording system was recently acquired, so that many of the procedures were performed with the old analog system and the new digital system to compare the performance of the digital system. 7 refs., 2 figs., 9 tabs.

  17. Calibration Laboratory Capabilities Listing as of April 2009

    NASA Technical Reports Server (NTRS)

    Kennedy, Gary W.

    2009-01-01

    This document reviews the Calibration Laboratory capabilities for various NASA centers (i.e., Glenn Research Center and Plum Brook Test Facility Kennedy Space Center Marshall Space Flight Center Stennis Space Center and White Sands Test Facility.) Some of the parameters reported are: Alternating current, direct current, dimensional, mass, force, torque, pressure and vacuum, safety, and thermodynamics parameters. Some centers reported other parameters.

  18. Source geometry factors for HDR ¹⁹²Ir brachytherapy secondary standard well-type ionization chamber calibrations.

    PubMed

    Shipley, D R; Sander, T; Nutbrown, R F

    2015-03-21

    Well-type ionization chambers are used for measuring the source strength of radioactive brachytherapy sources before clinical use. Initially, the well chambers are calibrated against a suitable national standard. For high dose rate (HDR) (192)Ir, this calibration is usually a two-step process. Firstly, the calibration source is traceably calibrated against an air kerma primary standard in terms of either reference air kerma rate or air kerma strength. The calibrated (192)Ir source is then used to calibrate the secondary standard well-type ionization chamber. Calibration laboratories are usually only equipped with one type of HDR (192)Ir source. If the clinical source type is different from that used for the calibration of the well chamber at the standards laboratory, a source geometry factor, k(sg), is required to correct the calibration coefficient for any change of the well chamber response due to geometric differences between the sources. In this work we present source geometry factors for six different HDR (192)Ir brachytherapy sources which have been determined using Monte Carlo techniques for a specific ionization chamber, the Standard Imaging HDR 1000 Plus well chamber with a type 70010 HDR iridium source holder. The calculated correction factors were normalized to the old and new type of calibration source used at the National Physical Laboratory. With the old Nucletron microSelectron-v1 (classic) HDR (192)Ir calibration source, ksg was found to be in the range 0.983 to 0.999 and with the new Isodose Control HDR (192)Ir Flexisource k(sg) was found to be in the range 0.987 to 1.004 with a relative uncertainty of 0.4% (k = 2). Source geometry factors for different combinations of calibration sources, clinical sources, well chambers and associated source holders, can be calculated with the formalism discussed in this paper.

  19. 10 CFR 35.432 - Calibration measurements of brachytherapy sources.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Calibration measurements of brachytherapy sources. 35.432 Section 35.432 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Manual Brachytherapy § 35.432 Calibration measurements of brachytherapy sources. (a) Before the first medical use of...

  20. 10 CFR 35.432 - Calibration measurements of brachytherapy sources.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Calibration measurements of brachytherapy sources. 35.432 Section 35.432 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Manual Brachytherapy § 35.432 Calibration measurements of brachytherapy sources. (a) Before the first medical use of...

  1. 10 CFR 35.432 - Calibration measurements of brachytherapy sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Calibration measurements of brachytherapy sources. 35.432 Section 35.432 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Manual Brachytherapy § 35.432 Calibration measurements of brachytherapy sources. (a) Before the first medical use of...

  2. 10 CFR 35.432 - Calibration measurements of brachytherapy sources.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Calibration measurements of brachytherapy sources. 35.432 Section 35.432 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Manual Brachytherapy § 35.432 Calibration measurements of brachytherapy sources. (a) Before the first medical use of...

  3. 10 CFR 35.432 - Calibration measurements of brachytherapy sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Calibration measurements of brachytherapy sources. 35.432 Section 35.432 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Manual Brachytherapy § 35.432 Calibration measurements of brachytherapy sources. (a) Before the first medical use of...

  4. Thermocouple Calibration and Accuracy in a Materials Testing Laboratory

    NASA Technical Reports Server (NTRS)

    Lerch, B. A.; Nathal, M. V.; Keller, D. J.

    2002-01-01

    A consolidation of information has been provided that can be used to define procedures for enhancing and maintaining accuracy in temperature measurements in materials testing laboratories. These studies were restricted to type R and K thermocouples (TCs) tested in air. Thermocouple accuracies, as influenced by calibration methods, thermocouple stability, and manufacturer's tolerances were all quantified in terms of statistical confidence intervals. By calibrating specific TCs the benefits in accuracy can be as great as 6 C or 5X better compared to relying on manufacturer's tolerances. The results emphasize strict reliance on the defined testing protocol and on the need to establish recalibration frequencies in order to maintain these levels of accuracy.

  5. Tritium monitor calibration at Los Alamos National Laboratory

    SciTech Connect

    Bjork, C.J.; Aikin, D.J.; Houlton, T.W.

    1997-08-01

    Tritium in air is monitored at Los Alamos National Laboratory (LANL) with air breathing instruments based on ionization chambers. Stack emissions are continuously monitored from sample tubes which each connect to a Tritium bubble which differentially collects HTO and HT. A set of glass vials of glycol capture the HTO. The HT is oxidized with a palladium catalyst and the resultant HTO is captured in a second set of vials of glycol. The glycol is counted with a liquid scintillation counter. All calibrations are performed with tritium containing gas. The Radiation Instrumentation and Calibration (RIC) Team has constructed and maintains two closed loop gas handling systems based on femto TECH model U24 tritium ion chamber monitors: a fixed system housed in a fume hood and a portable system mounted on two two wheeled hand trucks. The U24 monitors are calibrated against tritium in nitrogen gas standards. They are used as standard transfer instruments to calibrate other ion chamber monitors with tritium in nitrogen, diluted with air. The gas handling systems include a circulation pump which permits a closed circulation loop to be established among the U24 monitor and typically two to four other monitors of a given model during calibration. Fixed and portable monitors can be calibrated. The stack bubblers are calibrated in the field by: blending a known concentration of tritium in air within the known volume of the two portable carts, coupled into a common loop; releasing that gas mixture into a ventilation intake to the stack; collecting oxidized tritium in the bubbler; counting the glycol; and using the stack and bubbler flow rates, computing the bubbler`s efficiency. Gas calibration has become a convenient and quality tool in maintaining the tritium monitors at LANL.

  6. High dose calibrations at the pacific northwest laboratory

    NASA Astrophysics Data System (ADS)

    McDonald, J. C.; Fox, R. A.

    1989-04-01

    he need is increasing for both high radiation exposures and calibration measurements that provide traceability of such exposures to national standards. The applications of high exposures include: electronic component damage studies, sterilization of medical products and food irradiation. Accurate high exposure measurements are difficult to obtain and cannot, in general, be carried out with a single dose measurement system or technique because of the wide range of doses and the variety of materials involved. This paper describes the dosimetric measurement and calibration techniques used at the Pacific Northwest Laboratory (PNL) that make use of radiochromic dye films, thermoluminescence dosimeters (TLDs), ionization chambers and calorimetric dosimeters. The methods used to demonstrate the consistency of PNL calibrations with national standards will also be discussed.

  7. Vacuum-compatible standard diffuse source, manufacture and calibration

    SciTech Connect

    Byrd, D.A.; Atkins, W.H.; Bender, S.C.; Christensen, R.W.; Michaud, F.D.

    1999-03-01

    Los Alamos National Laboratories has completed the design, manufacture and calibration of a vacuum-compatible, tungsten lamp, integrated sphere. The light source has been calibrated at the National Institute of Standards and Technology (NIST) and is intended for use as a calibration standard for remote sensing instrumentation. Calibration 2{sigma} uncertainty varied with wavelength from 1.21% at 400 nm and 0.73% at 900 nm, to 3.95% at 2,400 nm. The inner radius of the Spectralon-coated sphere is 21.2 cm with a 7.4 cm square exit aperture. A small satellite sphere is attached to the main sphere and its output coupled through a stepper motor driven aperture. The variable aperture allows a constant radiance without effecting the color temperature output from the main sphere. The sphere`s output is transmitted into a vacuum test environment through a fused silica window that is an integral part of the outer housing of the vacuum shell assembly. The atmosphere within this outer housing is composed of 240 K nitrogen gas, provided by a custom LN{sub 2} vaporizer unit. Use of the nitrogen gas maintains the internal temperature of the sphere at a nominal 300 K {+-}10{degree}. The calibrated spectral range of the source is 0.4 {micro}m through 2.4 {micro}m. Three, color temperature matched, 20 W bulbs together with a 10 W bulb are within the main integrating sphere. Two 20 W bulbs, also color temperature matched, reside in the satellite integrating sphere. A Silicon and a Germanium broadband detector are situated within the inner surface of the main sphere. Their purpose is for the measurement of the internal broadband irradiance. A fiber-optic-coupled spectrometer measures the internal color temperature that is maintained by current control on the lamps. Each lamp is independently operated allowing for radiances with common color temperatures ranging from near 0.026 W/cm{sup 2}/sr to about 0.1 W/cm{sup 2}/sr at a wavelength of 0.9 {micro}m (the location of the peak spectral

  8. The Splatalogue (Spectral Line Catalogue) and Calibase (Calibration Source Database)

    NASA Astrophysics Data System (ADS)

    Markwick-Kemper, Andrew J.; Remijan, A. J.; Fomalont, E.

    2006-06-01

    The next generation of powerful millimeter/submillimeter observatories (ALMA, Herschel) require extensive resources to help identify spectral line transitions and suitable calibration sources. We describe the compilation of a spectral line catalogue and calibration source database. The Calibase is an extensible repository of measurements of radio and submm calibration sources, building on the SMA, PTCS, VLA and VLBA lists. The Splatalogue is a comprehensive transition-resolved compilation of observed, measured and calculated spectral lines. Extending the JPL and CDMS lists, and updating the Lovas/NIST list of observed astrophysical transitions, it adds atomic and recombination lines, template spectra, and is completely VO-compliant, queryable under the IVOA SLAP standard.

  9. 1992 Yearly calibration of Pacific Northwest Laboratory`s gross gamma-ray borehole geophysical logging system

    SciTech Connect

    Arthur, R J

    1992-07-01

    This report describes the 1992 yearly calibration of a gross gamma-ray geophysical pulse logging system owned by the US Department of Energy (DOE) and operated by Pacific Northwest Laboratory. The calibration was conducted to permit the continued use of this system for geologic and hydrologic studies associated with remedial investigation at the Hanford Site. The calibration is limited to the probe identified as CG27A-97. Primary calibrations to equivalent-uranium units were conducted in DOE borehole model standards that reside on the Hanford Site. The calibrations were performed in borehole models SBL/SBH and SBA/SBB, which contain low equivalent-uranium concentrations. A previous correlation for relating observed count rate in before- and after-logging field calibrations to equivalent-uranium concentrations was confirmed for field source Ra-20S-82. A computer-based digital collection/recording system was used simultaneously on many of the procedures with the original analog system so that the performance of the two collection systems could be correlated and compared at some future date.

  10. Dynamic size spectrometry of airborne microorganisms: Laboratory evaluation and calibration

    NASA Astrophysics Data System (ADS)

    Qian, Yinge; Willeke, Klaus; Ulevicius, Vidmantas; Grinshpun, Sergey A.; Donnelly, Jean

    Bioaerosol samplers need to be calibrated for the microorganisms of interest. The Aerosizer, a relatively new aerodynamic size spectrometer, is shown to be a suitable dynamic instrument for the evaluation and calibration of such samplers in the laboratory, prior to their use in the field. It provides the necessary reference count against which the microbiological response of the sampler can be compared. It measures the health-significant aerodynamic diameters of microorganisms down to 0.5 μm, thus including most of the bacteria, fungi and pollen found in outdoor and indoor air environments. Comparison tests with a laser size spectrometer indicate that the suspension of microorganisms needs to be washed several times before aerosolization to avoid coating of the airborne microorganisms with nutrients and microbial slime from the suspension, and to reduce the residue particles to sizes below the lowest size of the aerosolized microorganisms.

  11. Common Calibration Source for Monitoring Long-term Ozone Trends

    NASA Technical Reports Server (NTRS)

    Kowalewski, Matthew

    2004-01-01

    Accurate long-term satellite measurements are crucial for monitoring the recovery of the ozone layer. The slow pace of the recovery and limited lifetimes of satellite monitoring instruments demands that datasets from multiple observation systems be combined to provide the long-term accuracy needed. A fundamental component of accurately monitoring long-term trends is the calibration of these various instruments. NASA s Radiometric Calibration and Development Facility at the Goddard Space Flight Center has provided resources to minimize calibration biases between multiple instruments through the use of a common calibration source and standardized procedures traceable to national standards. The Facility s 50 cm barium sulfate integrating sphere has been used as a common calibration source for both US and international satellite instruments, including the Total Ozone Mapping Spectrometer (TOMS), Solar Backscatter Ultraviolet 2 (SBUV/2) instruments, Shuttle SBUV (SSBUV), Ozone Mapping Instrument (OMI), Global Ozone Monitoring Experiment (GOME) (ESA), Scanning Imaging SpectroMeter for Atmospheric ChartographY (SCIAMACHY) (ESA), and others. We will discuss the advantages of using a common calibration source and its effects on long-term ozone data sets. In addition, sphere calibration results from various instruments will be presented to demonstrate the accuracy of the long-term characterization of the source itself.

  12. 1993 yearly calibration of Pacific Northwest Laboratory`s gross gamma-ray borehole geophysical logging system

    SciTech Connect

    Arthur, R.J.

    1993-09-01

    This report describes the 1993 yearly calibration of a gross gamma-ray geophysical pulse logging system owned by the US Department of Energy (DOE) and operated by Pacific Northwest Laboratory. The calibration was conducted to permit the continued use of this system for geologic and hydrologic studies associated with remedial investigation at the Hanford Site. The calibration is limited to the probe identified as CG27A-97 and applies to a new probe detector crystal that replaced the former detector in January 1993, after a crack was discovered. Primary calibrations to equivalent-uranium units were conducted in DOE borehole model standards that reside on the Hanford Site. The calibrations were performed in borehole models SBL/SBH and SBA/SBB, which both contain sections with relatively low equivalent-uranium concentrations. Model SBH/SBL has now been countersunk at the site so that data were taken by suspending the probe downhole. Model SBA/SBB is still lying horizontally above ground at the site, so data were logged as in previous calibrations at the Hanford site by pushing the probe into the hole and drawing it out with the logging equipment. A previous correlation for relating observed count rate in before- and after-logging field calibrations to equivalent-uranium concentrations was confirmed for field source Ra-20S-82. A computer-based digital collection/recording system was used simultaneously on many of the procedures with the original analog system so that the performance of the two collection systems could be correlated and compared. The digital system was calibrated this year to confirm its linearity and to establish correlation with the analog data (i.e., chart-recorder output).

  13. Development of a system based on open source technology for DC resistor calibration

    NASA Astrophysics Data System (ADS)

    Geronymo, G. M.; Silva, M. C.

    2016-07-01

    This work present the development of a new system, based on open source technology, for the automation of DC resistor calibration. The new system is web-based, stores the measurement registers on a structured database and has new features that can increase the productivity of the laboratory. Some proposes of future development are presented, also.

  14. 1990 yearly calibration of Pacific Northwest Laboratory's gross-gamma borehole geophysical logging system

    SciTech Connect

    Arthur, R.J.

    1990-08-01

    This report describes the 1990 yearly calibration of a gross-gamma geophysical pulse logging system owned by the US Department of Energy (DOE) and operated by Pacific Northwest Laboratory (PNL). The calibration was conducted to permit the continued use of this system for geological and hydrologic studies associated with remedial investigation at the Hanford Site. Primary calibrations to equivalent uranium units were conducted in borehole model standards that were recently moved to the Hanford Site from the DOE field calibration facility in Spokane, Washington. The calibrations were performed in borehole models SBL/SBH and SBA/SBB, which contain low equivalent-uranium concentrations. The integrity of the system throughout the previous year from gamma-ray monitoring was demonstrated using the before- and after-logging field calibration readings with the field source in calibration Positions 1 and 2. Most of the Position 1 readings are within an 8% limit that is set by the governing PNL technical reference procedure as a critical value above which the instrument is considered suspect. Many of the Position 2 readings exceed the 8% limit; however, the fluctuation was traced to field-source geometry variability that affected Position 1 count rates by up to 6% and Position 2 count rates by as much as 16%. Correlations were established based on two similar approaches for relating observed count rate in before- and after-logging field calibrations to equivalent uranium concentrations. The temperature drift of the gamma-ray probe was documented and amounts to less than 0.1%/{degree}C within the temperature range 0{degree}C to 42{degree}C. The low-energy cutoff for the gross gamma-ray probe was determined to be between 46.5 and 59.5 keV. 10 refs., 4 figs., 13 tabs.

  15. Advanced development of internal calibration sources for remote sensing telescopes

    NASA Astrophysics Data System (ADS)

    Kintner, Eric C.; Hartley, Jeanne M.; Jacobs, Eric S.; Cucchiaro, Paul J.

    2004-11-01

    Contemporary and emerging sensor systems typically require in-flight calibration reference sources. These are required to satisfy increasingly stringent specifications for stability, repeatability, dynamic range, absolute irradiance accuracy, and irradiance distribution uniformity, while meeting stray light, weight, and power constraints. While SSG has successfully designed and flight-qualified an internal calibration source for a telescope in a Schmidt configuration, future remote sensing programs are more likely to require telescopes in a 3-mirror off-axis re-imaging configuration. A major advantage to developing an internal calibration reference source for a re-imaging telescope is the availability of an intermediate field stop where the illumination from the calibration source can be inserted into the optical train. SSG's internal source design offers important advantages over existing approaches using in-flight blackbodies, including reduced volume, weight, and power requirements and the ability to generate multiple irradiance levels over a short period of time. The GIFTS (Geosynchronous Imaging Fourier Transform Spectrometer) telescope has been used as a representative platform to demonstrate this new internal calibration source, as it is representative of a design that may be used for future programs including the HES (Hyperspectral Environmental Suite) telescopes.

  16. High intensity line source for x-ray spectrometer calibration

    SciTech Connect

    Thoe, R.S.

    1986-06-01

    A high intensity electron-impact x-ray source using a one-dimensional Pierce lens has been built for the purpose of calibrating a bent crystal x-ray spectrometer. This source focuses up to 100 mA of 20-keV electrons to a line on a liquid-cooled anode. The line (which can serve as a virtual slit for the spectrometer) measures approximately 800 ..mu.. x 2 cm. The source is portable and therefore adaptable to numerous types of spectrometer applications. One particular application, the calibration of a high resolution (r = 10/sup 4/) time-resolved cyrstal spectrometer, will be discussed in detail.

  17. Neutron calibration sources in the Daya Bay experiment

    DOE PAGES

    Liu, J.; Carr, R.; Dwyer, D. A.; Gu, W. Q.; Li, G. S.; McKeown, R. D.; Qian, X.; Tsang, R. H. M.; Wu, F. F.; Zhang, C.

    2015-07-09

    We describe the design and construction of the low rate neutron calibration sources used in the Daya Bay Reactor Anti-neutrino Experiment. Such sources are free of correlated gamma-neutron emission, which is essential in minimizing induced background in the anti-neutrino detector. Thus, the design characteristics have been validated in the Daya Bay anti-neutrino detector.

  18. 1992 Yearly calibration of Pacific Northwest Laboratory's gross gamma-ray borehole geophysical logging system

    SciTech Connect

    Arthur, R. J.

    1992-07-01

    This report describes the 1992 yearly calibration of a gross gamma-ray geophysical pulse logging system owned by the US Department of Energy (DOE) and operated by Pacific Northwest Laboratory. The calibration was conducted to permit the continued use of this system for geologic and hydrologic studies associated with remedial investigation at the Hanford Site. The calibration is limited to the probe identified as CG27A-97. Primary calibrations to equivalent-uranium units were conducted in DOE borehole model standards that reside on the Hanford Site. The calibrations were performed in borehole models SBL/SBH and SBA/SBB, which contain low equivalent-uranium concentrations. A previous correlation for relating observed count rate in before- and after-logging field calibrations to equivalent-uranium concentrations was confirmed for field source Ra-20S-82. A computer-based digital collection/recording system was used simultaneously on many of the procedures with the original analog system so that the performance of the two collection systems could be correlated and compared at some future date.

  19. Third-party brachytherapy source calibrations and physicist responsibilities: Report of the AAPM Low Energy Brachytherapy Source Calibration Working Group

    SciTech Connect

    Butler, Wayne M.; Bice, William S. Jr.; DeWerd, Larry A.; Hevezi, James M.; Huq, M. Saiful; Ibbott, Geoffrey S.; Palta, Jatinder R.; Rivard, Mark J.; Seuntjens, Jan P.; Thomadsen, Bruce R.

    2008-09-15

    The AAPM Low Energy Brachytherapy Source Calibration Working Group was formed to investigate and recommend quality control and quality assurance procedures for brachytherapy sources prior to clinical use. Compiling and clarifying recommendations established by previous AAPM Task Groups 40, 56, and 64 were among the working group's charges, which also included the role of third-party handlers to perform loading and assay of sources. This document presents the findings of the working group on the responsibilities of the institutional medical physicist and a clarification of the existing AAPM recommendations in the assay of brachytherapy sources. Responsibility for the performance and attestation of source assays rests with the institutional medical physicist, who must use calibration equipment appropriate for each source type used at the institution. Such equipment and calibration procedures shall ensure secondary traceability to a national standard. For each multi-source implant, 10% of the sources or ten sources, whichever is greater, are to be assayed. Procedures for presterilized source packaging are outlined. The mean source strength of the assayed sources must agree with the manufacturer's stated strength to within 3%, or action must be taken to resolve the difference. Third party assays do not absolve the institutional physicist from the responsibility to perform the institutional measurement and attest to the strength of the implanted sources. The AAPM leaves it to the discretion of the institutional medical physicist whether the manufacturer's or institutional physicist's measured value should be used in performing dosimetry calculations.

  20. Third-party brachytherapy source calibrations and physicist responsibilities: report of the AAPM Low Energy Brachytherapy Source Calibration Working Group.

    PubMed

    Butler, Wayne M; Bice, William S; DeWerd, Larry A; Hevezi, James M; Huq, M Saiful; Ibbott, Geoffrey S; Palta, Jatinder R; Rivard, Mark J; Seuntjens, Jan P; Thomadsen, Bruce R

    2008-09-01

    The AAPM Low Energy Brachytherapy Source Calibration Working Group was formed to investigate and recommend quality control and quality assurance procedures for brachytherapy sources prior to clinical use. Compiling and clarifying recommendations established by previous AAPM Task Groups 40, 56, and 64 were among the working group's charges, which also included the role of third-party handlers to perform loading and assay of sources. This document presents the findings of the working group on the responsibilities of the institutional medical physicist and a clarification of the existing AAPM recommendations in the assay of brachytherapy sources. Responsibility for the performance and attestation of source assays rests with the institutional medical physicist, who must use calibration equipment appropriate for each source type used at the institution. Such equipment and calibration procedures shall ensure secondary traceability to a national standard. For each multi-source implant, 10% of the sources or ten sources, whichever is greater, are to be assayed. Procedures for presterilized source packaging are outlined. The mean source strength of the assayed sources must agree with the manufacturer's stated strength to within 3%, or action must be taken to resolve the difference. Third party assays do not absolve the institutional physicist from the responsibility to perform the institutional measurement and attest to the strength of the implanted sources. The AAPM leaves it to the discretion of the institutional medical physicist whether the manufacturer's or institutional physicist's measured value should be used in performing dosimetry calculations. PMID:18841836

  1. Laboratory and field portable system for calibrating airborne multispectral scanners

    SciTech Connect

    Kuhlow, W.W.

    1981-01-01

    Manufacturers of airborne multispectral scanners suggest procedures for calibration and alignment that are usually awkward and even questionable. For example, the procedures may require: separating the scanner from calibration and alignment sources by 100 feet or more, employing folding mirrors, tampering with the detectors after the procedures are finished, etc. Under the best of conditions such procedures require about three hours yielding questionable confidence in the results; under many conditions, however, procedures commonly take six to eight hours, yielding no satisfactory results. EG and G, Inc. has designed and built a calibration and alignment system for airborne scanners which solves those problems, permitting the procedures to be carried out in about two to three hours. This equipment can be quickly disassembled, transported with the scanner in all but the smallest single engine aircraft, and reassembled in a few hours. The subsystems of this equipment are commonly available from manufacturers of optical and electronic equipment. The other components are easily purchased, or fabricated. The scanner discussed is the Model DS-1260 digital line scanner manufactured by Daedalus Enterprises, Inc. It is a dual-sensor system which is operated in one of two combination of sensors: one spectrometer head (which provides simultaneous coverage in ten visible channels) and one thermal infrared detector, or simply two thermal infrared detectors.

  2. Omega Dante soft x-ray power diagnostic component calibration at the National Synchrotron Light Source

    NASA Astrophysics Data System (ADS)

    Campbell, K. M.; Weber, F. A.; Dewald, E. L.; Glenzer, S. H.; Landen, O. L.; Turner, R. E.; Waide, P. A.

    2004-10-01

    The Dante soft x-ray spectrometer, installed on the Omega laser facility at the Laboratory for Laser Energetics, University of Rochester, is a 12-channel filter-edge defined soft x-ray power diagnostic. It is used to measure the spectrally resolved, absolute flux from direct drive, indirect drive (hohlraums) and other plasma sources. Dante component calibration efforts using two beam lines, U3C (50 eV-1 keV) and X8A (1-6 keV) at the National Synchrotron Light Source have been implemented to improve the accuracy of these measurements. We have calibrated metallic vacuum x-ray diodes, mirrors and filters.

  3. Omega Dante Soft X-Ray Power Diagnostic Component Calibration at the National Synchrotron Light Source

    SciTech Connect

    Campbell, K; Weber, F; Dewald, E; Glenzer, S; Landen, O; Turner, R; Waide, P

    2004-04-15

    The Dante soft x-ray spectrometer installed on the Omega laser facility at the Laboratory for Laser Energetics, University of Rochester is a twelve-channel filter-edge defined x-ray power diagnostic. It is used to measure the absolute flux from direct drive, indirect drive (hohlraums) and other plasma sources. Calibration efforts using two beam lines, U3C (50eV-1keV) and X8A (1keV-6keV) at the National Synchrotron Light Source (NSLS) have been implemented to insure the accuracy of these measurements. We have calibrated vacuum x-ray diodes, mirrors and filters.

  4. A dynamic pressure source for the calibration of pressure transducers

    NASA Technical Reports Server (NTRS)

    Vezzetti, C. F.; Hilten, J. S.; Mayo-Wells, J. F.; Lederer, P. S.

    1976-01-01

    A dynamic pressure source is described for producing sinusoidally varying pressures of up to 34 kPa zero to peak, over the frequency range of approximately 50 Hz to 2 kHz. The source is intended for the dynamic calibration of pressure transducers. The transducer to be calibrated is mounted near the base of the thick walled aluminum tube forming the vessel so that the pressure sensitive element is in contact with the liquid in the tube. A section of the tube is filled with small steel balls to damp the motion of the 10-St dimethyl siloxane working fluid in order to extend the useful frquency range to higher frequencies than would be provided by an undamped system. The dynamic response of six transducers provided by the sponsor was evaluated using the pressure sources; the results of these calibrations are given.

  5. Calibration of a DSSSD detector with radioactive sources

    SciTech Connect

    Guadilla, V.; Tain, J. L.; Agramunt, J.; Algora, A.; Domingo-Pardo, C.; Rubio, B.

    2013-06-10

    The energy calibration of a DSSSD is carried out with the spectra produced by a {sup 207}Bi conversion electron source, a {sup 137}Cs gamma source and a {sup 239}Pu/{sup 241}Am/{sup 244}Cm triple alpha source, as well as employing a precision pulse generator in the whole dynamic range. Multiplicity and coincidence of signals in different strips for the same event are also studied.

  6. Laboratory calibration of the Extreme-Ultraviolet Imaging Spectrometer for the Solar-B satellite

    SciTech Connect

    Lang, James; Kent, Barry J.; Paustian, Wolfgang; Brown, Charles M.; Keyser, Christian; Anderson, Mark R.; Case, Giles C. R.; Chaudry, Rahil A.; James, Adrian M.; Korendyke, Clarence M.; Pike, C. David; Probyn, Brian J.; Rippington, David J.; Seely, John F.; Tandy, Jason A.; Whillock, Matthew C. R

    2006-12-01

    The laboratory end-to-end testing of the Extreme-Ultraviolet Imaging Spectrometer (EIS) for the Solar-B satellite is reported. A short overview of the EIS, which observes in two bands in the extreme-ultraviolet wavelength range, is given. The calibration apparatus is described, including details of the light sources used.The data reduction and analysis procedure are outlined. The wavelength calibration using a Penning source to illuminate the aperture fully is presented. We discuss the aperture determination using a radiometrically calibrated hollow-cathode-based source. We then give an account of the predicted and measured efficiencies from consideration of the efficiencies of individual optical elements in first order, an account of efficiencies out of band when radiation incident in one band is detected in the other, and efficiencies in multiple orders. The efficiencies measured in first order for in band and out of band are compared with the predictions and the sensitivity, and its uncertainties are derived. Application of the radiometric calibration is discussed.

  7. Laboratory calibration of the Extreme-Ultraviolet Imaging Spectrometer for the Solar-B satellite.

    PubMed

    Lang, James; Kent, Barry J; Paustian, Wolfgang; Brown, Charles M; Keyser, Christian; Anderson, Mark R; Case, Giles C R; Chaudry, Rahil A; James, Adrian M; Korendyke, Clarence M; Pike, C David; Probyn, Brian J; Rippington, David J; Seely, John F; Tandy, Jason A; Whillock, Matthew C R

    2006-12-01

    The laboratory end-to-end testing of the Extreme-Ultraviolet Imaging Spectrometer (EIS) for the Solar-B satellite is reported. A short overview of the EIS, which observes in two bands in the extreme-ultraviolet wavelength range, is given. The calibration apparatus is described, including details of the light sources used. The data reduction and analysis procedure are outlined. The wavelength calibration using a Penning source to illuminate the aperture fully is presented. We discuss the aperture determination using a radiometrically calibrated hollow-cathode-based source. We then give an account of the predicted and measured efficiencies from consideration of the efficiencies of individual optical elements in first order, an account of efficiencies out of band when radiation incident in one band is detected in the other, and efficiencies in multiple orders. The efficiencies measured in first order for in band and out of band are compared with the predictions and the sensitivity, and its uncertainties are derived. Application of the radiometric calibration is discussed.

  8. Irradiance Calibration Using a Cryogenic Radiometer and a Broadband Light Source

    NASA Astrophysics Data System (ADS)

    Morrill, J. S.; McMullin, D.; Floyd, L. E.; Lorentz, S. R.; Korendyke, C. M.

    2009-12-01

    Total solar irradiance measurements have been made from space based instruments for the past several decades. Due to a variety of reasons which range from instrumental degradation to differences in optical design, the data from these sources have proved difficult to overlap and place on an absolute scale. Some previous calibration efforts have used the sun as a source while operating the instrument in a large vacuum chamber. More recent efforts to provide ground based, pre-flight intercomparisons between flight radiometers and recently developed high power cryogenic radiometers using lasers. We are currently developing a calibration facility at The Naval Research Laboratory which uses a high power cryogenic radiometer with a broadband light source with near solar illumination. The system uses a very low scattered light vacuum calibration tank used to perform the stray light tests of the LASCO and SECCHI coronagraphs on the SOHO and STEREO missions. This presentation will address the status of our system, recent measurements, and future plans.

  9. Ceramic ChemCam Calibration Targets on Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Vaniman, D.; Dyar, M. D.; Wiens, R.; Ollila, A.; Lanza, N.; Lasue, J.; Rhodes, J. M.; Clegg, S.; Newsom, H.

    2012-09-01

    The ChemCam instrument on the Mars Science Laboratory rover Curiosity will use laser-induced breakdown spectroscopy (LIBS) to analyze major and minor element chemistry from sub-millimeter spot sizes, at ranges of ˜1.5-7 m. To interpret the emission spectra obtained, ten calibration standards will be carried on the rover deck. Graphite, Ti metal, and four glasses of igneous composition provide primary, homogeneous calibration targets for the laser. Four granular ceramic targets have been added to provide compositions closer to soils and sedimentary materials like those expected at the Gale Crater field site on Mars. Components used in making these ceramics include basalt, evaporite, and phyllosilicate materials that approximate the chemical compositions of detrital and authigenic constituents of clastic and evaporite sediments, including the elevated sulfate contents present in many Mars sediments and soils. Powdered components were sintered at low temperature (800 °C) with a small amount (9 wt.%) of lithium tetraborate flux to produce ceramics that retain volatile sulfur yet are durable enough for the mission. The ceramic targets are more heterogeneous than the pure element and homogenous glass standards but they provide standards with compositions more similar to the sedimentary rocks that will be Curiosity's prime targets at Gale Crater.

  10. Active radiometric calorimeter for absolute calibration of radioactive sources

    SciTech Connect

    Stump, K.E.; DeWerd, L.A.; Rudman, D.A.; Schima, S.A.

    2005-03-01

    This report describes the design and initial noise floor measurements of a radiometric calorimeter designed to measure therapeutic medical radioactive sources. The instrument demonstrates a noise floor of approximately 2 nW. This low noise floor is achieved by using high temperature superconducting (HTS) transition edge sensor (TES) thermometers in a temperature-control feedback loop. This feedback loop will be used to provide absolute source calibrations based upon the electrical substitution method. Other unique features of the calorimeter are (a) its ability to change sources for calibration without disrupting the vacuum of the instrument, and (b) the ability to measure the emitted power of a source in addition to the total contained source power.

  11. Absolute calorimetric calibration of low energy brachytherapy sources

    NASA Astrophysics Data System (ADS)

    Stump, Kurt E.

    In the past decade there has been a dramatic increase in the use of permanent radioactive source implants in the treatment of prostate cancer. A small radioactive source encapsulated in a titanium shell is used in this type of treatment. The radioisotopes used are generally 125I or 103Pd. Both of these isotopes have relatively short half-lives, 59.4 days and 16.99 days, respectively, and have low-energy emissions and a low dose rate. These factors make these sources well suited for this application, but the calibration of these sources poses significant metrological challenges. The current standard calibration technique involves the measurement of ionization in air to determine the source air-kerma strength. While this has proved to be an improvement over previous techniques, the method has been shown to be metrologically impure and may not be the ideal means of calbrating these sources. Calorimetric methods have long been viewed to be the most fundamental means of determining source strength for a radiation source. This is because calorimetry provides a direct measurement of source energy. However, due to the low energy and low power of the sources described above, current calorimetric methods are inadequate. This thesis presents work oriented toward developing novel methods to provide direct and absolute measurements of source power for low-energy low dose rate brachytherapy sources. The method is the first use of an actively temperature-controlled radiation absorber using the electrical substitution method to determine total contained source power of these sources. The instrument described operates at cryogenic temperatures. The method employed provides a direct measurement of source power. The work presented here is focused upon building a metrological foundation upon which to establish power-based calibrations of clinical-strength sources. To that end instrument performance has been assessed for these source strengths. The intent is to establish the limits of

  12. Calibration of a time-resolved hard-x-ray detector using radioactive sources

    NASA Astrophysics Data System (ADS)

    Stoeckl, C.; Theobald, W.; Regan, S. P.; Romanofsky, M. H.

    2016-11-01

    A four-channel, time-resolved, hard x-ray detector (HXRD) has been operating at the Laboratory for Laser Energetics for more than a decade. The slope temperature of the hot-electron population in direct-drive inertial confinement fusion experiments is inferred by recording the hard x-ray radiation generated in the interaction of the electrons with the target. Measuring the energy deposited by hot electrons requires an absolute calibration of the hard x-ray detector. A novel method to obtain an absolute calibration of the HXRD using single photons from radioactive sources was developed, which uses a thermoelectrically cooled, low-noise, charge-sensitive amplifier.

  13. Primary calibrations of radionuclide solutions and sources for the EML quality assessment program

    SciTech Connect

    Fisenne, I.M.

    1993-12-31

    The quality assurance procedures established for the operation of the U.S. Department of Energy`s Environmental Measurements Laboratory (DOE-EML`s) Quality Assessment Program (QAP) are essentially the same as those that are in effect for any EML program involving radiometric measurements. All these programs have at their core the use of radionuclide standards for their instrument calibration. This paper focuses on EML`s approach to the acquisition, calibration and application of a wide range of radionuclide sources that are required to meet its programmatic needs.

  14. On the Error Sources in Absolute Individual Antenna Calibrations

    NASA Astrophysics Data System (ADS)

    Aerts, Wim; Baire, Quentin; Bilich, Andria; Bruyninx, Carine; Legrand, Juliette

    2013-04-01

    The two main methods for antenna calibration currently in use, are anechoic chamber measurements on the one hand and outdoor robot calibration on the other hand. Both techniques differ completely in approach, setup and data processing. Consequently, the error sources for both techniques are totally different as well. Except for the (near field) multi path error, caused by the antenna positioning device, that alters results for both calibration methods. But not necessarily with the same order of magnitude. Literature states a (maximum deviation) repeatability for robot calibration of choke ring antennas of 0.5 mm on L1 and 1 mm on L2 [1]. For anechoic chamber calibration, a value of 1.5 mm on L2 for a resistive ground plane antenna can be found in [2]. Repeatability however masks systematic errors linked with the calibration technique. Hence, comparing an individual calibration obtained with a robot to a calibration of the same antenna in an anechoic chamber, may result in differences that surpass these repeatability thresholds. This was the case at least for all six choke ring antennas studied. The order of magnitude of the differences moreover corresponded well to the values given for a LEIAT504GG in [3]. For some error sources, such as the GNSS receiver measurement noise or the VNA measurement noise, estimates can be obtained from manufacturer specifications in data sheets. For other error sources, such as the finite distance between transmit and receive antenna, or the limited attenuation of reflections on wall absorber, back-of-the-envelope calculations can be made to estimate their order of magnitude. For the error due to (near field) multi path this is harder to do, if not impossible. The more because this strongly depends on the antenna type and its mount. Unfortunately it is, again, this (near field) multi path influence that might void the calibration once the antenna is installed at the station. Hence it can be concluded that at present, due to (near

  15. Neutron Calibration Facilities of the Irsn Research Laboratory in External Dosimetry

    NASA Astrophysics Data System (ADS)

    van Ryckeghem, L.; Lacoste, V.; Pelcot, G.; Pochat, J.-L.

    2003-06-01

    The Laboratory of Studies and Research in External Dosimetry (LRDE) associated to the National Office for Metrology (BNM) has to maintain the traceability of the French references for the calibration of neutron dosimeters. The LRDE owns a facility which provides some conventional neutron spectra from sources of 241Am-Be, 252Cf, and (252Cf + D2O)/Cd recommended by ISO standards. These ISO spectra appear not appropriated to simulate some kind of workplace spectra. In order to have similar radiation conditions between the calibration and the use of the device, LRDE has built facilities ("SIGMA" and "CANEL") providing some neutron spectra from thermal to fast energies reproducing those encountered in workplaces.

  16. Laboratory-Based BRDF Calibration of Radiometric Tarps

    NASA Technical Reports Server (NTRS)

    Georgiev, Georgi T.; Butler, James J.

    2007-01-01

    The current study provides the remote sensing community with important high accuracy laboratory-based BRDF calibration of radiometric tarps. The results illustrate the dependence of tarps' weft and warp threads orientation on BRDF. The study was done at incident angles of 0deg, 10deg, and 30deg; scatter zenith angles from 0deg to 60deg, and scatter azimuth angles of 0deg, 45deg, 90deg, 135deg, and 180deg. The wavelengths were 485nm, 550nm, 633nm and 800nm. The dependence is well defined at all measurement geometries and wavelengths. It can be as high as 8% at 0deg incident angle and 2% at 30deg incident angle. The fitted BRDF data show a very small discrepancy from the measured ones. New data on the forward and backscatter properties of radiometric tarps is reported. The backward scatter is well pronounced for the white samples. The black sample has well pronounced forward scatter. The BRDF characterization of radiometric tarps can be successfully extended to other structured surface fabric samples. The results are NIST traceable.

  17. Comparison of pencil-type ionization chamber calibration results and methods between dosimetry laboratories.

    PubMed

    Hourdakis, Costas J; Büermann, Ludwig; Ciraj-Bjelac, Olivera; Csete, Istvan; Delis, Harry; Gomola, Igor; Persson, Linda; Novak, Leos; Petkov, Ivailo; Toroi, Paula

    2016-01-01

    A comparison of calibration results and procedures in terms of air kerma length product, PKL, and air kerma, K, was conducted between eight dosimetry laboratories. A pencil-type ionization chamber (IC), generally used for computed tomography dose measurements, was calibrated according to three calibration methods, while its residual signal and other characteristics (sensitivity profile, active length) were assessed. The results showed that the "partial irradiation method" is the preferred method for the pencil-type IC calibration in terms of PKL and it could be applied by the calibration laboratories successfully. Most of the participating laboratories achieved high level of agreement (>99%) for both dosimetry quantities (PKL and K). Estimated relative standard uncertainties of comparison results vary among laboratories from 0.34% to 2.32% depending on the quantity, beam quality and calibration method applied. Detailed analysis of the assigned uncertainties have been presented and discussed.

  18. Comparison of Blackbody Sources for Low-Temperature IR Calibration

    NASA Astrophysics Data System (ADS)

    Ljungblad, S.; Holmsten, M.; Josefson, L. E.; Klason, P.

    2015-12-01

    Radiation thermometers are traditionally mostly used in high-temperature applications. They are, however, becoming more common in different applications at room temperature or below, in applications such as monitoring frozen food and evaluating heat leakage in buildings. To measure temperature accurately with a pyrometer, calibration is essential. A problem with traditional, commercially available, blackbody sources is that ice is often formed on the surface when measuring temperatures below 0°C. This is due to the humidity of the surrounding air and, as ice does not have the same emissivity as the blackbody source, it biases the measurements. An alternative to a traditional blackbody source has been tested by SP Technical Research Institute of Sweden. The objective is to find a cost-efficient method of calibrating pyrometers by comparison at the level of accuracy required for the intended use. A disc-shaped blackbody with a surface pyramid pattern is placed in a climatic chamber with an opening for field of view of the pyrometer. The temperature of the climatic chamber is measured with two platinum resistance thermometers in the air in the vicinity of the disc. As a rule, frost will form only if the deposition surface is colder than the surrounding air, and, as this is not the case when the air of the climatic chamber is cooled, there should be no frost or ice formed on the blackbody surface. To test the disc-shaped blackbody source, a blackbody cavity immersed in a conventional stirred liquid bath was used as a reference blackbody source. Two different pyrometers were calibrated by comparison using the two different blackbody sources, and the results were compared. The results of the measurements show that the disc works as intended and is suitable as a blackbody radiation source.

  19. Automatic pneumatic source-control system for positioning gamma and neutron calibration sources

    SciTech Connect

    Hunt, G.F.

    1980-10-17

    A microcomputer-based source-control system was developed to move gamma and neutron calibration sources into position for sample irradiation. In addition to monitoring interlocks and system status, the computer calculates for gamma sources the time required for a requested exposure at a specified distance. All system use data is stored, and monthly reports are generated.

  20. Development of a quality assurance program for ionizing radiation secondary calibration laboratories

    SciTech Connect

    Heaton, H.T. II; Taylor, A.R. Jr.

    1993-12-31

    For calibration laboratories, routine calibrations of instruments meeting stated accuracy goals are important. One method of achieving the accuracy goals is to establish and follow a quality assurance program designed to monitor all aspects of the calibration program and to provide the appropriate feedback mechanism if adjustments are needed. In the United States there are a number of organizations with laboratory accreditation programs. All existing accreditation programs require that the laboratory implement a quality assurance program with essentially the same elements in all of these programs. Collectively, these elements have been designated as a Measurement Quality Assurance (MQA) program. This paper will briefly discuss the interrelationship of the elements of an MQA program. Using the Center for Devices and Radiological Health (CDRH) X-ray Calibration Laboratory (XCL) as an example, it will focus on setting up a quality control program for the equipment in a Secondary Calibration Laboratory.

  1. Brookhaven National Laboratory meteorological services instrument calibration plan and procedures

    SciTech Connect

    Heiser .

    2013-02-16

    This document describes the Meteorological Services (Met Services) Calibration and Maintenance Schedule and Procedures, The purpose is to establish the frequency and mechanism for the calibration and maintenance of the network of meteorological instrumentation operated by Met Services. The goal is to maintain the network in a manner that will result in accurate, precise and reliable readings from the instrumentation.

  2. Multi-source self-calibration: Unveiling the microJy population of compact radio sources

    NASA Astrophysics Data System (ADS)

    Radcliffe, J. F.; Garrett, M. A.; Beswick, R. J.; Muxlow, T. W. B.; Barthel, P. D.; Deller, A. T.; Middelberg, E.

    2016-03-01

    Context. Very long baseline interferometry (VLBI) data are extremely sensitive to the phase stability of the VLBI array. This is especially important when we reach μJy rms sensitivities. Calibration using standard phase-referencing techniques is often used to improve the phase stability of VLBI data, but the results are often not optimal. This is evident in blank fields that do not have in-beam calibrators. Aims: We present a calibration algorithm termed multi-source self-calibration (MSSC) which can be used after standard phase referencing on wide-field VLBI observations. This is tested on a 1.6 GHz wide-field VLBI data set of the Hubble Deep Field North and the Hubble Flanking Fields. Methods: MSSC uses multiple target sources that are detected in the field via standard phase referencing techniques and modifies the visibilities so that each data set approximates to a point source. These are combined to increase the signal to noise and permit self-calibration. In principle, this should allow residual phase changes caused by the troposphere and ionosphere to be corrected. By means of faceting, the technique can also be used for direction-dependent calibration. Results: Phase corrections, derived using MSSC, were applied to a wide-field VLBI data set of the HDF-N, which comprises of 699 phase centres. MSSC was found to perform considerably better than standard phase referencing and single source self-calibration. All detected sources exhibited dramatic improvements in dynamic range. Using MSSC, one source reached the detection threshold, taking the total detected sources to twenty. This means 60% of these sources can now be imaged with uniform weighting, compared to just 45% with standard phase referencing. In principle, this technique can be applied to any future VLBI observations. The Parseltongue code, which implements MSSC, has been released and made publicly available to the astronomical community (http://https://github.com/jradcliffe5/multi_self_cal).

  3. Two laboratory methods for the calibration of GPS speed meters

    NASA Astrophysics Data System (ADS)

    Bai, Yin; Sun, Qiao; Du, Lei; Yu, Mei; Bai, Jie

    2015-01-01

    The set-ups of two calibration systems are presented to investigate calibration methods of GPS speed meters. The GPS speed meter calibrated is a special type of high accuracy speed meter for vehicles which uses Doppler demodulation of GPS signals to calculate the measured speed of a moving target. Three experiments are performed: including simulated calibration, field-test signal replay calibration, and in-field test comparison with an optical speed meter. The experiments are conducted at specific speeds in the range of 40-180 km h-1 with the same GPS speed meter as the device under calibration. The evaluation of measurement results validates both methods for calibrating GPS speed meters. The relative deviations between the measurement results of the GPS-based high accuracy speed meter and those of the optical speed meter are analyzed, and the equivalent uncertainty of the comparison is evaluated. The comparison results justify the utilization of GPS speed meters as reference equipment if no fewer than seven satellites are available. This study contributes to the widespread use of GPS-based high accuracy speed meters as legal reference equipment in traffic speed metrology.

  4. A new standard cylindrical graphite-walled ionization chamber for dosimetry in 60Co beams at calibration laboratories

    NASA Astrophysics Data System (ADS)

    Neves, Lucio P.; Perini, Ana P.; Caldas, Linda V. E.

    2014-11-01

    60Co sources are used mostly at dosimetry laboratories for calibration of ionization chambers utilized for radiotherapy dosimetry, mainly in those laboratories where there is no linear accelerator available. In this work, a new cylindrical ionization chamber was developed and characterized to be used as a reference dosimeter at the Calibration Laboratory of the IPEN. The characterization tests were performed according to the IEC 60731 standard, and all tests presented results within its recommended limits. Furthermore, the correction factors for the wall, stem, central collecting electrode, nonaxial uniformity and the mass-energy absorption coefficient were determined using the EGSnrc Monte Carlo code. The air kerma rate determined with this new dosimeter was compared to the one obtained with the IPEN standard, presenting a difference of 1.5%. Therefore, the new ionization chamber prototype developed and characterized in this work presents potential use as a primary standard dosimeter at radiation metrology laboratories.

  5. Laboratory Calibration of a Field Imaging Spectrometer System

    PubMed Central

    Zhang, Lifu; Huang, Changping; Wu, Taixia; Zhang, Feizhou; Tong, Qingxi

    2011-01-01

    A new Field Imaging Spectrometer System (FISS) based on a cooling area CCD was developed. This paper describes the imaging principle, structural design, and main parameters of the FISS sensor. The FISS was spectrally calibrated with a double grating monochromator to determine the center wavelength and FWHM of each band. Calibration results showed that the spectral range of the FISS system is 437–902 nm, the number of channels is 344 and the spectral resolution of each channel is better than 5 nm. An integrating sphere was used to achieve absolute radiometric calibration of the FISS with less than 5% calibration error for each band. There are 215 channels with signal to noise ratios (SNRs) greater than 500 (62.5% of the bands). The results demonstrated that the FISS has achieved high performance that assures the feasibility of its practical use in various fields. PMID:22163746

  6. Laboratory calibration of a field imaging spectrometer system.

    PubMed

    Zhang, Lifu; Huang, Changping; Wu, Taixia; Zhang, Feizhou; Tong, Qingxi

    2011-01-01

    A new Field Imaging Spectrometer System (FISS) based on a cooling area CCD was developed. This paper describes the imaging principle, structural design, and main parameters of the FISS sensor. The FISS was spectrally calibrated with a double grating monochromator to determine the center wavelength and FWHM of each band. Calibration results showed that the spectral range of the FISS system is 437-902 nm, the number of channels is 344 and the spectral resolution of each channel is better than 5 nm. An integrating sphere was used to achieve absolute radiometric calibration of the FISS with less than 5% calibration error for each band. There are 215 channels with signal to noise ratios (SNRs) greater than 500 (62.5% of the bands). The results demonstrated that the FISS has achieved high performance that assures the feasibility of its practical use in various fields.

  7. The SeaWiFS Quality Monitor: A Portable Field Calibration Light Source

    NASA Technical Reports Server (NTRS)

    Shaw, Ping-Shine; Johnson, B. Carol; Hooker, Stanford B.; Lynch, Don

    1997-01-01

    A portable and stable source, the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Quality Monitor, has been developed for use as a field instrument. The source can be used with either radiance- or irradiance-measuring sensors to transfer the laboratory calibration to the field so that the stability of the sensors can be monitored during the experiment. Temperature-controlled silicon photodiodes with colored glass filters are used to monitor the stability of the SeaWiFS Quality Monitor.

  8. Characteristics of the Neutron Irradiation Facilities of the PSI Calibration Laboratory

    SciTech Connect

    Hoedlmoser, H.; Schuler, Ch.; Butterweck, G.; Mayer, S.

    2011-12-13

    The neutron radiation fields of the Calibration Laboratory at Paul Scherrer Institute (PSI) are traceable to the national standards of the Physikalisch-Technische Bundesanstalt (PTB) in Germany. A Berthold LB6411 neutron dose rate meter for neutron radiation is used as a secondary standard. Recently, a thorough characterization of the neutron irradiation fields of the {sup 241}Am-Be and {sup 252}Cf sources by means of reference measurements and a detailed MCNPX simulation of the irradiation facility has been initiated. In this work, the characteristics of the neutron radiation fields are summarized and presented together with model equations and an uncertainty analysis. MCNPX results are shown for the {sup 241}Am-Be source. A comparison of measured and simulated data shows an excellent agreement. From the simulation, valuable information about the neutron fields like the contribution of scattered neutrons in the fields and the energy spectra could be obtained.

  9. Monte Carlo study of a 60Co calibration field of the Dosimetry Laboratory Seibersdorf.

    PubMed

    Hranitzky, C; Stadtmann, H

    2007-01-01

    The gamma radiation fields of the reference irradiation facility of the Dosimetry Laboratory Seibersdorf with collimated beam geometry are used for calibrating radiation protection dosemeters. A close-to-reality simulation model of the facility including the complex geometry of a 60Co source was set up using the Monte Carlo code MCNP. The goal of this study is to characterise the radionuclide gamma calibration field and resulting air-kerma distributions inside the measurement hall with a total of 20 m in length. For the whole range of source-detector-distances (SDD) along the central beam axis, simulated and measured relative air-kerma values are within +/-0.6%. Influences on the accuracy of the simulation results are investigated, including e.g., source mass density effects or detector volume dependencies. A constant scatter contribution from the lead ring-collimator of approximately 1% and an increasing scatter contribution from the concrete floor for distances above 7 m are identified, resulting in a total air-kerma scatter contribution below 5%, which is in accordance to the ISO 4037-1 recommendations.

  10. A report from the AVS Standards Committee - Comparison of ion gauge calibrations by several standards laboratories

    NASA Technical Reports Server (NTRS)

    Warshawsky, I.

    1982-01-01

    Calibrations by four U.S. laboratories of four hot-cathode ion gauges, in the range 0.07-13 mPa, showed systematic differences among laboratories that were much larger than the expected error of any one calibration. They also suggested that any of the four gauges tested, if properly packaged and shipped, was able to serve as a transfer standard with probable error of 2%. A second comparison was made of the calibrations by two U.S. laboratories of some other gauges that had also been calibrated by the National Physical Laboratory, England. Results did not permit conclusive determination of whether differences were due to the laboratories or to changes in the gauges.

  11. Study and mitigation of calibration error sources in a water vapour Raman lidar

    NASA Astrophysics Data System (ADS)

    David, Leslie; Bock, Olivier; Bosser, Pierre; Thom, Christian; Pelon, Jacques

    2014-05-01

    gain and spatial inhomogeneity in the sensitivity of the photomultiplier photocathode,…) separately using theoretical analysis, numerical and optical simulations, and laboratory experiments. The instability induced by the use of an optics fibre for coupling the signal collected by the telescope to the detectors is especially investigated. We quantified the impact of all these error sources on the water vapour and nitrogen Raman channels measurements and on the change in the differential calibration constant and we tried to implement an experimental solution to minimize the variations.

  12. Calibration of Radiation Thermometers up to : Effective Emissivity of the Source

    NASA Astrophysics Data System (ADS)

    Kozlova, O.; Briaudeau, S.; Rongione, L.; Bourson, F.; Guimier, S.; Kosmalski, S.; Sadli, M.

    2015-08-01

    The growing demand of industry for traceable temperature measurements up to encourages improvement of calibration techniques for industrial-type radiation thermometers in this temperature range. High-temperature fixed points can be used at such high temperatures, but due to the small diameter of apertures of their cavities (3 mm), they are not adapted for the large field-of-views commonly featured by this kind of radiation thermometers. At LNE-Cnam, a Thermo Gauge furnace of 25.4 mm source aperture diameter is used as a comparison source to calibrate customers' instruments against a reference radiation thermometer calibrated according to the ITS-90 with the lowest uncertainties achievable in the Laboratory. But the furnace blackbody radiator exhibits a large temperature gradient that degrades its effective emissivity, and increases the calibration uncertainty due to the lack of information on the working spectral band of the industrial radiation thermometer. In order to estimate the corrections to apply, the temperature distribution (radial and on-axis) of the Thermo Gauge furnace blackbody radiator was characterized and the effective emissivity of the Thermo Gauge cavity was determined by three different methods. Because of this investigation, the corrections due to different fields of view and due to the different spectral bands of the reference pyrometer and the customer's pyrometer were obtained and the uncertainties on these corrections were evaluated.

  13. 10 CFR 35.2432 - Records of calibration measurements of brachytherapy sources.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Records of calibration measurements of brachytherapy... Records § 35.2432 Records of calibration measurements of brachytherapy sources. (a) A licensee shall maintain a record of the calibrations of brachytherapy sources required by § 35.432 for 3 years after...

  14. 10 CFR 35.2432 - Records of calibration measurements of brachytherapy sources.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Records of calibration measurements of brachytherapy... Records § 35.2432 Records of calibration measurements of brachytherapy sources. (a) A licensee shall maintain a record of the calibrations of brachytherapy sources required by § 35.432 for 3 years after...

  15. 10 CFR 35.2432 - Records of calibration measurements of brachytherapy sources.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Records of calibration measurements of brachytherapy... Records § 35.2432 Records of calibration measurements of brachytherapy sources. (a) A licensee shall maintain a record of the calibrations of brachytherapy sources required by § 35.432 for 3 years after...

  16. 10 CFR 35.2432 - Records of calibration measurements of brachytherapy sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Records of calibration measurements of brachytherapy... Records § 35.2432 Records of calibration measurements of brachytherapy sources. (a) A licensee shall maintain a record of the calibrations of brachytherapy sources required by § 35.432 for 3 years after...

  17. 10 CFR 35.2432 - Records of calibration measurements of brachytherapy sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Records of calibration measurements of brachytherapy... Records § 35.2432 Records of calibration measurements of brachytherapy sources. (a) A licensee shall maintain a record of the calibrations of brachytherapy sources required by § 35.432 for 3 years after...

  18. Calibration of R/V Marcus G. Langseth Seismic Sources

    NASA Astrophysics Data System (ADS)

    Diebold, J.; Tolstoy, M.; Webb, S.; Doermann, L.; Bohenstihl, D.; Nooner, S.; Crone, T.; Holmes, R. C.

    2008-12-01

    NSF-owned Research Vessel Marcus G. Langseth is operated by Lamont-Doherty Earth Observatory, providing the tools for full-scale marine seismic surveys to the academic community. Since inauguration of science operations, Langseth has successfully supported 2D and 3D seismic operations, including offshore- onshore and OBS refraction profiling A significant component of Langseths equipage is the seismic source, comprising four identical linear subarrays which can be combined in a number of configurations according to the needs of each scientific mission. To ensure a full understanding of the acoustic levels of these sources and in order to mitigate their possible impact upon marine life through accurate determination of safety radii, an extensive program of acoustic calibration was carried out in 2007 and 2008, during Langseths shakedown exercises. A total of 14000+ airgun array discharges were recorded in three separate locations with water depths varying from 1750 to 45 meters and at source-receiver offsets between near-zero and 17 km. The quantity of data recorded allows significant quantitative analysis of the sound levels produced by the Langseth seismic sources. A variety of acoustic metrics will be presented and compared, including peak levels and energy-based measures such as RMS, Energy Flux Density and its equivalent, Sound Exposure Level. It is clearly seen that water depth exerts a fundamental control on received sound levels, but also that these effects can be predicted with reasonable accuracy.

  19. QA experience at the University of Wisconsin accredited dosimetry calibration laboratory

    SciTech Connect

    DeWard, L.A.; Micka, J.A.

    1993-12-31

    The University of Wisconsin Accredited Dosimetry Calibration Laboratory (UW ADCL) employs procedure manuals as part of its Quality Assurance (QA) program. One of these manuals covers the QA procedures and results for all of the UW ADCL measurement equipment. The QA procedures are divided into two main areas: QA for laboratory equipment and QA for external chambers sent for calibration. All internal laboratory equipment is checked and recalibrated on an annual basis, after establishing its consistency on a 6-month basis. QA for external instruments involves checking past calibration history as well as comparing to a range of calibration values for specific instrument models. Generally, the authors find that a chamber will have a variation of less than 0.5 % from previous Co-60 calibration factors, and falls within two standard deviations of previous calibrations. If x-ray calibrations are also performed, the energy response of the chamber is plotted and compared to previous instruments of the same model. These procedures give the authors confidence in the transfer of calibration values from National Institute of Standards and Technology (NIST).

  20. Services of the CDRH X-ray calibration laboratory and their traceability to National Standards

    SciTech Connect

    Cerra, F.; Heaton, H.T.

    1993-12-31

    The X-ray Calibration Laboratory (XCL) of the Center for Devices and Radiological Health (CDRH) provides calibration services for the Food and Drug Administration (FDA). The instruments calibrated are used by FDA and contract state inspectors to verify compliance with federal x-ray performance standards and for national surveys of x-ray trends. In order to provide traceability of measurements, the CDRH XCL is accredited by the National Voluntary Laboratory Accreditation Program (NVLAP) for reference, diagnostic, and x-ray survey instrument calibrations. In addition to these accredited services, the CDRH XCL also calibrates non-invasive kVp meters in single- and three-phase x-ray beams, and thermoluminescent dosimeter (TLD) chips used to measure CT beam profiles. The poster illustrates these services and shows the traceability links back to the National Standards.

  1. Aqueous blackbody calibration source for millimeter-wave/terahertz metrology

    SciTech Connect

    Dietlein, Charles; Popovic, Zoya; Grossman, Erich N

    2008-10-20

    This paper describes a calibrated broadband emitter for the millimeter-wave through terahertz frequency regime, called the aqueous blackbody calibration source. Due to its extremely high absorption, liquid water is chosen as the emitter on the basis of reciprocity. The water is constrained to a specific shape (an optical trap geometry) in an expanded polystyrene (EPS) container and maintained at a selected, uniform temperature. Uncertainty in the selected radiometric temperature due to the undesirable reflectance present at a water interface is minimized by the trap geometry, ensuring that radiation incident on the entrance aperture encounters a pair of s and a pair of p reflections at 45 deg. . For water reflectance Rw of 40% at 45 deg. in W-band, this implies a theoretical effective aperture emissivity of (1-R{sup 2}wsR{sup 2}wp)>98.8%. From W-band to 450 GHz, the maximum radiometric temperature uncertainty is {+-}0.40 K, independent of water temperature. Uncertainty from 450 GHz to 1 THz is increased due to EPS scattering and absorption, resulting in a maximum uncertainty of -3 K at 1 THz.

  2. Aqueous blackbody calibration source for millimeter-wave/terahertz metrology.

    PubMed

    Dietlein, Charles; Popović, Zoya; Grossman, Erich N

    2008-10-20

    This paper describes a calibrated broadband emitter for the millimeter-wave through terahertz frequency regime, called the aqueous blackbody calibration source. Due to its extremely high absorption, liquid water is chosen as the emitter on the basis of reciprocity. The water is constrained to a specific shape (an optical trap geometry) in an expanded polystyrene (EPS) container and maintained at a selected, uniform temperature. Uncertainty in the selected radiometric temperature due to the undesirable reflectance present at a water interface is minimized by the trap geometry, ensuring that radiation incident on the entrance aperture encounters a pair of s and a pair of p reflections at 45 degrees. For water reflectance R(w) of 40% at 45 degrees in W-band, this implies a theoretical effective aperture emissivity of (1-R(2)(ws)R(2)(wp))>98.8%. From W-band to 450 GHz, the maximum radiometric temperature uncertainty is +/-0.40 K, independent of water temperature. Uncertainty from 450 GHz to 1 THz is increased due to EPS scattering and absorption, resulting in a maximum uncertainty of -3 K at 1 THz.

  3. MAARSY multiple receiver phase calibration using radio sources

    NASA Astrophysics Data System (ADS)

    Chau, Jorge L.; Renkwitz, Toralf; Stober, Gunter; Latteck, Ralph

    2014-10-01

    The Middle Atmosphere Alomar Radar System (MAARSY) on the Norwegian island of Andøya is a 53.5 MHz monostatic radar with an active phased array antenna. The total array consists of 433 3-element linearly polarized Yagi antennas and can be configured to receive with multiple antenna sections (currently up to 16 complex receiving channels). In order to exploit its multiple-receiver capability for improving the space-time ambiguities of atmospheric/ionospheric targets, the phase difference between receiving channels has to be measured with good precision. Such phases are intrinsic to the system and are due to different cable lengths, pointing positions, filters, attenuators, amplifiers, antenna impedances, etc. In this work, we have operated MAARSY in a radio passive mode to observe the strong radio signals of Cassiopeia A and Cygnus A sources and calibrate the receiving system. By using the so-called fringe-stopping method, we have been able to calibrate the 16 complex channels, including the smaller antenna module that can be used, i.e., an Hexagon consisting of 7 Yagi antennas. The measured phases have been obtained with a mean standard deviation of ∼5°. We have tested the validity of such phases using meteor-head echoes with different configurations and pointing directions. Given that the procedure is easy to implement, it should be used in a routine manner either to corroborate the stability of the system or to measure new phases after upgrades or repairs.

  4. Modeling Study of a Proposed Field Calibration Source Using K-40 and High-Z Targets for Sodium Iodide Detectors.

    PubMed

    Rogers, Jeremy; Marianno, Craig; Kallenbach, Gene; Trevino, Jose

    2016-06-01

    Calibration sources based on the primordial isotope potassium-40 (K) have reduced controls on the source's activity due to its terrestrial ubiquity and very low specific activity. Potassium-40's beta emissions and 1,460.8 keV gamma ray can be used to induce K-shell fluorescence x rays in high-Z metals between 60 and 80 keV. A gamma ray calibration source that uses potassium chloride salt and a high-Z metal to create a two-point calibration for a sodium iodide field gamma spectroscopy instrument is thus proposed. The calibration source was designed in collaboration with the Sandia National Laboratory using the Monte Carlo N-Particle eXtended (MCNPX) transport code. Two methods of x-ray production were explored. First, a thin high-Z layer (HZL) was interposed between the detector and the potassium chloride-urethane source matrix. Second, bismuth metal powder was homogeneously mixed with a urethane binding agent to form a potassium chloride-bismuth matrix (KBM). The bismuth-based source was selected as the development model because it is inexpensive, nontoxic, and outperforms the high-Z layer method in simulation. Based on the MCNPX studies, sealing a mixture of bismuth powder and potassium chloride into a thin plastic case could provide a light, inexpensive field calibration source. PMID:27115223

  5. The Corinth Rift Laboratory (CRL) strainmeters: calibration and data analysis

    NASA Astrophysics Data System (ADS)

    Canitano, A.; Bernard, P.; Linde, A. T.; Sacks, S. I.; Boudin, F.

    2010-12-01

    The Gulf of Corinth (Greece) is one of the most seismic regions in Europe, producing some strong earthquakes in the decades, 1 to 1.5 cm/yr of north-south extension, and frequent seismic swarms. This structure is a 110 km long, N110E oriented graben bounded by systems of very recent normal faults. The Corinth Rift Laboratory (CRL) project is concentrated in the western part of the rift, around the city of Aigion, where instrumental seismicity and strain rate is highest. The CRL Network is made up about fifteen seismic stations as well as tiltmeters, strainmeters or GPS in order to study the local seismicity, and to observe and model the short and long term mechanics of the normal fault system. The instrumental seismicity in the Aigion zone clearly shows a strong concentration of small earthquakes between 5 and 10 km. In order to study slow transient deformation,two borehole strainmeters have been installed in the area (Trizonia, Monasteraki). We focus here on the one installed in the Trizonia island, which is continuously recording the horizontal strain at 150 m depth with a short term resolution better than 10-9. The dominant signal is the earth and sea tidal effects (few 10-7 strain), this one is modulated by the mechanical effects of the free oscillations of the Gulf with periods between 8 and 40 min. The barometric pressure fluctuations acts in combination with the mean sea level variation at longer periods and both effects are not independant. The comparison between the strain data and the two forcing signals exhibits a non zero phase delay of the sea-level which is increasing with period. We estimate a transfer function after few correlation iterations for each forcing signal but the physical interpretation of the sea-level function is still unclear. As the strainmeter is at 150 m depth, below the shoreline, a sea water percolation on land would increase the effect of sea level fluctuation, and be more efficient at longer periods. The dilatometer response to

  6. RadBall Technology Testing in the Savannah River Site's Health Physics Instrument Calibration Laboratory.

    PubMed

    Farfán, Eduardo B; Foley, Trevor Q; Jannik, G Timothy; Harpring, Larry J; Gordon, John R; Blessing, Ronald; Coleman, J Rusty; Holmes, Christopher J; Oldham, Mark; Adamovics, John; Stanley, Steven J

    2010-01-01

    The United Kingdom's National Nuclear Laboratory (NNL) has developed a radiation-mapping device that can locate and quantify radioactive hazards within contaminated areas of the nuclear industry. The device, known as RadBall(™), consists of a colander-like outer collimator that houses a radiation-sensitive polymer sphere. The collimator has over two hundred small holes; thus, specific areas of the polymer sphere are exposed to radiation becoming increasingly more opaque in proportion to the absorbed dose. The polymer sphere is imaged in an optical-CT scanner that produces a high resolution 3D map of optical attenuation coefficients. Subsequent analysis of the optical attenuation data provides information on the spatial distribution of sources in a given area forming a 3D characterization of the area of interest. The RadBall(™) technology has been deployed in a number of technology trials in nuclear waste reprocessing plants at Sellafield in the United Kingdom and facilities of the Savannah River National Laboratory (SRNL). This paper summarizes the tests completed at SRNL Health Physics Instrument Calibration Laboratory (HPICL).

  7. RADBALL TECHNOLOGY TESTING IN THE SAVANNAH RIVER SITE HEALTH PHYSICS INSTRUMENT CALIBRATION LABORATORY

    SciTech Connect

    Farfan, E.

    2010-07-08

    The United Kingdom's National Nuclear Laboratory (NNL) has developed a radiation-mapping device that can locate and quantify radioactive hazards within contaminated areas of the nuclear industry. The device, known as RadBall{trademark}, consists of a colander-like outer collimator that houses a radiation-sensitive polymer sphere. The collimator has over two hundred small holes; thus, specific areas of the polymer sphere are exposed to radiation becoming increasingly more opaque in proportion to the absorbed dose. The polymer sphere is imaged in an optical-CT scanner that produces a high resolution 3D map of optical attenuation coefficients. Subsequent analysis of the optical attenuation data provides information on the spatial distribution of sources in a given area forming a 3D characterization of the area of interest. The RadBallTM technology has been deployed in a number of technology trials in nuclear waste reprocessing plants at Sellafield in the United Kingdom and facilities of the Savannah River National Laboratory (SRNL). This paper summarizes the tests completed at SRNL Health Physics Instrument Calibration Laboratory (HPICL).

  8. VizieR Online Data Catalog: Interferometer phase calibration sources (Patnaik+ 1998)

    NASA Astrophysics Data System (ADS)

    Patnaik, A. R.; Browne, I. W. A.; Wilkinson, P. N.; Wrobel, J. M.

    2000-01-01

    The catalogue contains compact radio sources with accurate positions observed with the Very Large Array (VLA). These sources are primarily intended for use as phase calibration sources for the Multi-Element Radio Linked Interferometer Network (MERLIN); the sources are also suitable as phase calibrators for the VLA and can be considered as candidate phase calibrators for very long-baseline interferometry (VLBI) networks. The accuracy of the position is 12 mas for sources in Paper I, 14 mas for sources in Paper II, and 55 mas for sources in Paper III. (2 data files).

  9. Hidden sources of mercury in clinical laboratories.

    PubMed

    Alvarez-Chavez, C R; Federico-Perez, R A; Gomez-Alvarez, A; Velazquez-Contreras, L E; Perez-Rios, R

    2014-09-01

    The healthcare sector is an important contributor to mercury (Hg) pollution because of the potential presence of mercury in thermometers, blood pressure cuffs, amalgams, etc. There are also other potential sources of mercury in this sector which are used frequently and in high volumes where the presence of the metal is not obvious and which might be collectively contributing to pollution. For instance, some chemicals used for the clinical diagnosis of illness may contain mercury. The goal of this study was to investigate potential sources of mercury pollution, which originate from clinical laboratory discharges, using an exploratory approach. The focus was on the residue generated during automatic analysis of patients' bodily fluids at a medical center in Hermosillo, Sonora, Mexico. This study shows an overview of what might be happening in the region or the country related to non-obvious sources of mercury in the healthcare sector. The results showed measurable levels of mercury in the residues coming from urine sediment analysis. These amounts do not exceed the maximum allowed by Mexican environmental regulations; nevertheless, the frequency and cumulative volume of residues generated, combined with the potential for persistence and the bioaccumulation of mercury in the environment, warrant attention. The work carried out in this study is being taken as a model for future studies for pollution prevention in the healthcare sector with the goal of measuring mercury emissions to the environment from clinical laboratory wastewater, including identifying sources which--while not obvious--could be important given the frequency and volume of their use in the clinical diagnosis.

  10. Angular response calibration of the burst and transient source experiment

    NASA Technical Reports Server (NTRS)

    Lestrade, John Patrick

    1988-01-01

    The Gamma Ray Observatory includes four experiments designed to observe the gamma-ray universe. Laboratory measurements to test the response the Burst and Transient Source Experiment (BATSE) modules to gamma-ray sources that are non-axial were recently completed. The results of these observations are necessary for the correct interpretation of BATSE data obtained after it is put in Earth orbit. The launch is planned for March, 1900. Preliminary analyses of these test data show the presence of a radial dependence to the detector's light collection efficiency. It is proposed to evaluate the importance of this radial response, analyze future experimental data to derive the actual functional dependence on radius, and calculate the net effect on the output spectrum as a function of the angle of incidence.

  11. 10 CFR 35.65 - Authorization for calibration, transmission, and reference sources.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Authorization for calibration, transmission, and reference... General Technical Requirements § 35.65 Authorization for calibration, transmission, and reference sources... any of the following byproduct material for check, calibration, transmission, and reference use....

  12. Dealing with the size-of-source effect in the calibration of direct-reading radiation thermometer

    SciTech Connect

    Saunders, P.

    2013-09-11

    The majority of general-purpose low-temperature handheld radiation thermometers are severely affected by the size-of-source effect (SSE). Calibration of these instruments is pointless unless the SSE is accounted for in the calibration process. Traditional SSE measurement techniques, however, are costly and time consuming, and because the instruments are direct-reading in temperature, traditional SSE results are not easily interpretable, particularly by the general user. This paper describes a simplified method for measuring the SSE, suitable for second-tier calibration laboratories and requiring no additional equipment, and proposes a means of reporting SSE results on a calibration certificate that should be easily understood by the non-specialist user.

  13. Energy calibration of energy-resolved photon-counting pixel detectors using laboratory polychromatic x-ray beams

    NASA Astrophysics Data System (ADS)

    Youn, Hanbean; Han, Jong Chul; Kam, Soohwa; Yun, Seungman; Kim, Ho Kyung

    2014-10-01

    Recently, photon-counting detectors capable of resolving incident x-ray photon energies have been considered for use in spectral x-ray imaging applications. For reliable use of energy-resolved photon-counting detectors (ERPCDs), energy calibration is an essential procedure prior to their use because variations in responses from each pixel of the ERPCD for incident photons, even at the same energy, are inevitable. Energy calibration can be performed using a variety of methods. In all of these methods, the photon spectra with well-defined peak energies are recorded. Every pixel should be calibrated on its own. In this study, we suggest the use of a conventional polychromatic x-ray source (that is typically used in laboratories) for energy calibration. The energy calibration procedure mainly includes the determination of the peak energies in the spectra, flood-field irradiation, determination of peak channels, and determination of calibration curves (i.e., the slopes and intercepts of linear polynomials). We applied a calibration algorithm to a CdTe ERPCD comprised of 128×128 pixels with a pitch of 0.35 mm using highly attenuated polychromatic x-ray beams to reduce the pulse pile-up effect, and to obtain a narrow-shaped spectrum due to beam hardening. The averaged relative error in calibration curves obtained from 16,384 pixels was about 0.56% for 59.6 keV photons from an Americium radioisotope. This pixel-by-pixel energy calibration enhanced the signal- and contrast-to-noise ratios in images, respectively, by a factor of ~5 and 3 due to improvement in image homogeneity, compared to those obtained without energy calibration. One secondary finding of this study was that the x-ray photon spectra obtained using a common algorithm for computing x-ray spectra reasonably described the peaks in the measured spectra, which implies easier peak detection without the direct measurement of spectra using a separate spectrometer. The proposed method will be a useful alternative to

  14. Precision current control for quantum cascade lasers as flight calibration sources

    NASA Astrophysics Data System (ADS)

    Hansen, Stewart M.

    A space-grade-equivalent precision current controller for quantum cascade lasers (QCLs) is presented. This current controller design will enable constant wave (CW) or pulsed mode operation of QCL devices as calibration sources in a space environment. One major source of sensitivity in current controllers is temperature variation across the electronics board. This design integrates some methods used by Pacific Northwest National Laboratory (PNNL) to compensate for these sensitivites. An uncertainty analysis of the key components of the space-grade-equivialent current controller was performed to estimate changes in QCL output power due to a change of 1°C. The performed uncertainty analysis shows that the design has the capability to control the current to within the 0.1% output power stability goal with a change of +/-10°C in the precision current controller electronics.

  15. Issues in Absolute Spectral Radiometric Calibration: Intercomparison of Eight Sources

    NASA Technical Reports Server (NTRS)

    Goetz, Alexander F. H.; Kindel, Bruce; Pilewskie, Peter

    1998-01-01

    The application of atmospheric models to AVIRIS and other spectral imaging data to derive surface reflectance requires that the sensor output be calibrated to absolute radiance. Uncertainties in absolute calibration are to be expected, and claims of 92% accuracy have been published. Measurements of accurate surface albedos and cloud absorption to be used in radiative balance calculations depend critically on knowing the absolute spectral-radiometric response of the sensor. The Earth Observing System project is implementing a rigorous program of absolute radiometric calibration for all optical sensors. Since a number of imaging instruments that provide output in terms of absolute radiance are calibrated at different sites, it is important to determine the errors that can be expected among calibration sites. Another question exists about the errors in the absolute knowledge of the exoatmospheric spectral solar irradiance.

  16. History, organization, and oversight of the accredited dosimetry calibration laboratories by the AAPM

    SciTech Connect

    Rozenfeld, M.

    1993-12-31

    For more than 20 years, the American Association of Physicists in Medicine (AAPM) has operated an accreditation program for secondary standards laboratories that calibrate radiation measuring instruments. Except for one short period, that program has been able to provide the facilities to satisfy the national need for accurate calibrations of such instruments. That exception, in 1981, due to the combination of the U.S. Nuclear Regulatory Commission (NRC) requiring instrument calibrations by users of cobalt-60 teletherapy units and the withdrawal of one of the three laboratories accredited at that time. However, after successful operation as a Task Group of the Radiation Therapy Committee (RTC) of the AAPM for two decades, a reorganization of this structure is now under serious consideration by the administration of the AAPM.

  17. Phased Array Radiometer Calibration Using a Radiated Noise Source

    NASA Technical Reports Server (NTRS)

    Srinivasan, Karthik; Limaye, Ashutoch S.; Laymon, Charles A.; Meyer, Paul J.

    2010-01-01

    Electronic beam steering capability of phased array antenna systems offer significant advantages when used in real aperture imaging radiometers. The sensitivity of such systems is limited by the ability to accurately calibrate variations in the antenna circuit characteristics. Passive antenna systems, which require mechanical rotation to scan the beam, have stable characteristics and the noise figure of the antenna can be characterized with knowledge of its physical temperature [1],[2]. Phased array antenna systems provide the ability to electronically steer the beam in any desired direction. Such antennas make use of active components (amplifiers, phase shifters) to provide electronic scanning capability while maintaining a low antenna noise figure. The gain fluctuations in the active components can be significant, resulting in substantial calibration difficulties [3]. In this paper, we introduce two novel calibration techniques that provide an end-to-end calibration of a real-aperture, phased array radiometer system. Empirical data will be shown to illustrate the performance of both methods.

  18. Laboratory Calibration of the Optical Transient Detector (OTD) and the Lightning Imaging Sensor (LIS)

    NASA Technical Reports Server (NTRS)

    Koshak, William J.; Stewart, Mike F.; Christian, Hugh J.; Bergstrom, James W.; Hall, John M.; Solakiewicz, Richard J.

    1994-01-01

    We present in detail the laboratory apparatus and techniques that were used to complete a full radiometric calibration of two space-based lightning detectors developed at NASA Marshall Space Flight Center (MSFC). A discussion of the methods applied to geolocate lightning and to estimate lightning detection efficiency are provided.

  19. Comparison of two pyrometers used to calibrate Primary Standards Laboratory's tungsten filament lamps

    SciTech Connect

    Odom, M.K.

    1987-01-01

    The Primary Standards Laboratory presently uses an automatic optical pyrometer with a photomultiplier tube photodetector to calibrate tungsten filament lamps. This pyrometer is compared to a newly designed direct optical pyrometer with a photodiode photodetector. Though the direct pyrometer looks promising, final improvements are necessary to make a conclusive comparison.

  20. 10 CFR 70.19 - General license for calibration or reference sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... section, plutonium in the form of calibration or reference sources: (1) Any person in a non-agreement... plutonium in such sources; (2) Shall not receive, possess, use or transfer such source unless the source, or... regulatory authority. Do not remove this label. caution—radioactive material—this source contains...

  1. 10 CFR 70.19 - General license for calibration or reference sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... section, plutonium in the form of calibration or reference sources: (1) Any person in a non-agreement... plutonium in such sources; (2) Shall not receive, possess, use or transfer such source unless the source, or... regulatory authority. Do not remove this label. caution—radioactive material—this source contains...

  2. A database of phase calibration sources and their radio spectra for the Giant Metrewave Radio Telescope

    NASA Astrophysics Data System (ADS)

    Lal, Dharam V.; Dubal, Shilpa S.; Sherkar, Sachin S.

    2016-10-01

    We are pursuing a project to build a database of phase calibration sources suitable for Giant Metrewave Radio Telescope (GMRT). Here we present the first release of 45 low frequency calibration sources at 235 MHz and 610 MHz. These calibration sources are broadly divided into quasars, radio galaxies and unidentified sources. We provide their flux densities, models for calibration sources, (u,v) plots, final deconvolved restored maps and uc(clean)-component lists/files for use in the Astronomical Image Processing System (uc(aips)) and the Common Astronomy Software Applications (uc(casa)). We also assign a quality factor to each of the calibration sources. These data products are made available online through the GMRT observatory website. In addition we find that (i) these 45 low frequency calibration sources are uniformly distributed in the sky and future efforts to increase the size of the database should populate the sky further, (ii) spectra of these calibration sources are about equally divided between straight, curved and complex shapes, (iii) quasars tend to exhibit flatter radio spectra as compared to the radio galaxies or the unidentified sources, (iv) quasars are also known to be radio variable and hence possibly show complex spectra more frequently, and (v) radio galaxies tend to have steeper spectra, which are possibly due to the large redshifts of distant galaxies causing the shift of spectrum to lower frequencies.

  3. A new facility for the synchrotron radiation-based calibration of transfer radiation sources in the ultraviolet and vacuum ultraviolet spectral range

    SciTech Connect

    Thornagel, Reiner; Fliegauf, Rolf; Klein, Roman Kroth, Simone; Paustian, Wolfgang; Richter, Mathias

    2015-01-15

    The Physikalisch-Technische Bundesanstalt (PTB) has a long tradition in the calibration of radiation sources in the ultraviolet and vacuum ultraviolet spectral range, with traceability to calculable synchrotron radiation. Within this context, new instrumentation in the PTB laboratory at the Metrology Light Source (MLS) has been put into operation that opens up extended and improved calibration possibilities. A new facility for radiation source calibrations has been set up in the spectral range from 7 nm to 400 nm based on a combined normal incidence-grazing incidence monochromator. The facility can be used for the calibration of transfer sources in terms of spectral radiant intensity or mean spectral radiance, with traceability to the MLS primary source standard. We describe the design and performance of the experimental station and give examples of some commissioning results.

  4. Effect of multiple error sources on the calibration uncertainty.

    PubMed

    Badocco, Denis; Lavagnini, Irma; Mondin, Andrea; Pastore, Paolo

    2015-06-15

    The calibration uncertainty associated with the determination of metals at trace levels in a drinking water sample by ICP-MS was estimated when signals were affected by two error contributions, namely instrumental errors and operational condition errors. The calibration uncertainty was studied by using J concentration levels measured I times, as usual in experimental calibration procedures. The instrumental error was random in character whilst the operational error was assumed systematic at each concentration level but random among the J levels. The presence or the absence of the two error contributions was determined with an F-test between the ordinary least squares residual variance of the mean responses at each concentration and a pooled variance of the replicates. The theory was applied to the calibration of 30 elements present in a multi-standard solution and then to the analysis of boron, calcium, lithium, barium and manganese in a real drinking water sample. The need of using the proposed approach as calibration for almost all the analyzed elements resulted evident. The presence or the absence of the two error contributions was determined with an F-test between the ordinary least squares residual variance of the mean responses at each concentration and a pooled variance of the replicates. It was found that in the former instance the uncertainty determined using a two-components variance regression was greater than that obtainable from the one-variance regression.

  5. Characterization and Calibration of the CheMin Mineralogical Instrument on Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Blake, David; Vaniman, David; Achilles, Cherie; Anderson, Robert; Bish, David; Bristow, Tom; Chen, Curtis; Chipera, Steve; Crisp, Joy; Des Marais, David; Downs, Robert T.; Farmer, Jack; Feldman, Sabrina; Fonda, Mark; Gailhanou, Marc; Ma, Hongwei; Ming, Doug W.; Morris, Richard V.; Sarrazin, Philippe; Stolper, Ed; Treiman, Allan; Yen, Albert

    2012-09-01

    A principal goal of the Mars Science Laboratory (MSL) rover Curiosity is to identify and characterize past habitable environments on Mars. Determination of the mineralogical and chemical composition of Martian rocks and soils constrains their formation and alteration pathways, providing information on climate and habitability through time. The CheMin X-ray diffraction (XRD) and X-ray fluorescence (XRF) instrument on MSL will return accurate mineralogical identifications and quantitative phase abundances for scooped soil samples and drilled rock powders collected at Gale Crater during Curiosity's 1-Mars-year nominal mission. The instrument has a Co X-ray source and a cooled charge-coupled device (CCD) detector arranged in transmission geometry with the sample. CheMin's angular range of 5∘ to 50∘ 2 θ with <0.35∘ 2 θ resolution is sufficient to identify and quantify virtually all minerals. CheMin's XRF requirement was descoped for technical and budgetary reasons. However, X-ray energy discrimination is still required to separate Co K α from Co K β and Fe K α photons. The X-ray energy-dispersive histograms (EDH) returned along with XRD for instrument evaluation should be useful in identifying elements Z>13 that are contained in the sample. The CheMin XRD is equipped with internal chemical and mineralogical standards and 27 reusable sample cells with either Mylar® or Kapton® windows to accommodate acidic-to-basic environmental conditions. The CheMin flight model (FM) instrument will be calibrated utilizing analyses of common samples against a demonstration-model (DM) instrument and CheMin-like laboratory instruments. The samples include phyllosilicate and sulfate minerals that are expected at Gale crater on the basis of remote sensing observations.

  6. Factors affecting the repeatability of gamma camera calibration for quantitative imaging applications using a sealed source

    NASA Astrophysics Data System (ADS)

    Anizan, N.; Wang, H.; Zhou, X. C.; Wahl, R. L.; Frey, E. C.

    2015-02-01

    Several applications in nuclear medicine require absolute activity quantification of single photon emission computed tomography images. Obtaining a repeatable calibration factor that converts voxel values to activity units is essential for these applications. Because source preparation and measurement of the source activity using a radionuclide activity meter are potential sources of variability, this work investigated instrumentation and acquisition factors affecting repeatability using planar acquisition of sealed sources. The calibration factor was calculated for different acquisition and geometry conditions to evaluate the effect of the source size, lateral position of the source in the camera field-of-view (FOV), source-to-camera distance (SCD), and variability over time using sealed Ba-133 sources. A small region of interest (ROI) based on the source dimensions and collimator resolution was investigated to decrease the background effect. A statistical analysis with a mixed-effects model was used to evaluate quantitatively the effect of each variable on the global calibration factor variability. A variation of 1 cm in the measurement of the SCD from the assumed distance of 17 cm led to a variation of 1-2% in the calibration factor measurement using a small disc source (0.4 cm diameter) and less than 1% with a larger rod source (2.9 cm diameter). The lateral position of the source in the FOV and the variability over time had small impacts on calibration factor variability. The residual error component was well estimated by Poisson noise. Repeatability of better than 1% in a calibration factor measurement using a planar acquisition of a sealed source can be reasonably achieved. The best reproducibility was obtained with the largest source with a count rate much higher than the average background in the ROI, and when the SCD was positioned within 5 mm of the desired position. In this case, calibration source variability was limited by the quantum noise.

  7. Ultra-Compact Imaging Spectrometer (UCIS) for In-Situ Planetary Mineralogy: Laboratory and Field Calibration

    NASA Technical Reports Server (NTRS)

    Van Gorp, Byron; Mouroulis, Pantazis; Green, Robert O.; Rodriguez, Jose I.; Blaney, Diana; Wilson, Daniel W.; Sellar, R. Glenn; Richardson, Brandon S.

    2012-01-01

    The Ultra-Compact Imaging Spectrometer (UCIS) is a miniature telescope and spectrometer system intended for mapping terrain mineralogy over distances from 1.5 m to infinity with spatial sampling of 1.35 mrad over a 33 deg field, and spectral sampling of 10 nm in the 600-2500 nm range. The core of the system has been designed for operation in a Martian environment, but can also be used in a terrestrial environment when placed inside a vacuum vessel. We report the laboratory and field calibration data that include spatial and spectral calibration, and demonstrate the use of the system.

  8. Usefulness of specific calibration coefficients for gamma-emitting sources measured by radionuclide calibrators in nuclear medicine

    SciTech Connect

    Bochud, Francois O.; Laedermann, Jean-Pascal; Baechler, Sebastien; Kosinski, Marek; Bailat, Claude J.

    2011-07-15

    Purpose: In nuclear medicine, the activity of a radionuclide is measured with a radionuclide calibrator that often has a calibration coefficient independent of the container type and filling. Methods: To determine the effect of the container on the accuracy of measuring the activity injected into a patient, The authors simulated a commercial radionuclide calibrator and 18 container types most typically used in clinical practice. The instrument sensitivity was computed for various container thicknesses and filling levels. Monoenergetic photons and electrons as well as seven common radionuclides were considered. Results: The quality of the simulation with gamma-emitting sources was validated by an agreement with measurements better than 4% in five selected radionuclides. The results show that the measured activity can vary by more than a factor of 2 depending on the type of container. The filling level and the thickness of the container wall only have a marginal effect for radionuclides of high energy but could induce differences up to 4%. Conclusions: The authors conclude that radionuclide calibrators should be tailored to the uncertainty required by clinical applications. For most clinical cases, and at least for the low-energy gamma and x-ray emitters, measurements should be performed with calibration coefficients specific to the container type.

  9. 10 CFR 35.65 - Authorization for calibration, transmission, and reference sources.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Authorization for calibration, transmission, and reference sources. 35.65 Section 35.65 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL General Technical Requirements § 35.65 Authorization for calibration, transmission, and reference...

  10. Radio Astronomical Polarimetry and Point-Source Calibration

    NASA Astrophysics Data System (ADS)

    van Straten, W.

    2004-05-01

    A mathematical framework is presented for use in the experimental determination of the polarimetric response of observatory instrumentation. Elementary principles of linear algebra are applied to model the full matrix description of the polarization measurement equation by least-squares estimation of nonlinear, scalar parameters. The formalism is applied to calibrate the center element of the Parkes Multibeam receiver using observations of the millisecond pulsar PSR J0437-4715 and the radio galaxy 3C 218 (Hydra A).

  11. Satellite-mounted Light Source as Photometric Calibration Standards

    NASA Astrophysics Data System (ADS)

    Albert, J.; Burgett, W.; Rhodes, J.; Battat, J.

    At AMOS 2006 we proposed a tunable laser-based satellite-mounted spectrophotometric and absolute flux calibration system, to be utilized by ground- and space-based telescopes, for precision calibration of ground-based telescope photometry and flux. Since then, we have performed a campaign of observations of the 532 nm pulsed laser aboard the CALIPSO satellite (launched Apr. 2006), using a portable network of cameras and NIST-calibrated photodiodes, to test the precision of this method of measuring atmospheric extinction. This technique has astrophysical applications including reducing a major systematic uncertainty (absolute photometry) on cosmological parameter measurement using type Ia supernovae, as well as in upcoming photometric red shift surveys measuring growth of large scale structure in the Universe. In addition, upcoming systems potentially have broad utility for defense and national security applications such as ground target illumination and space communication. We will report on our measurements using our observations of the CALIPSO laser, and discuss future directions and applications. For further details please see http://www.arxiv.org/abs/astro-ph/0604339 and http://www8.nationalacademies.org/astro2010/DetailFileDisplay.aspx?id=546.

  12. Facility for spectral irradiance and radiance responsivity calibrations using uniform sources

    SciTech Connect

    Brown, Steven W.; Eppeldauer, George P.; Lykke, Keith R

    2006-11-10

    Detectors have historically been calibrated for spectral power responsivity at the National Institute of Standards and Technology by using a lamp-monochromator system to tune the wavelength of the excitation source. Silicon detectors can be calibrated in the visible spectral region with combined standard uncertainties at the 0.1% level. However,uncertainties increase dramatically when measuring an instrument's spectral irradiance or radiance responsivity. We describe what we believe to be a new laser-based facility for spectral irradiance and radiance responsivity calibrations using uniform sources (SIRCUS) that was developed to calibrate instruments directly in irradiance or radiance mode with uncertainties approaching or exceeding those available for spectral power responsivity calibrations. In SIRCUS, the emission from high-power, tunable lasers is introduced into an integrating sphere using optical fibers, producing uniform, quasi-Lambertian, high-radiant-flux sources. Reference standard irradiance detectors, calibrated directly against national primary standards for spectral power responsivity and aperture area measurement,are used to determine the irradiance at a reference plane. Knowing the measurement geometry, the source radiance can be readily determined as well. The radiometric properties of the SIRCUS source coupled with state-of-the-art transfer standard radiometers whose responsivities are directly traceable to primary national radiometric scales result in typical combined standard uncertainties in irradiance and radiance responsivity calibrations of less than 0.1%. The details of the facility and its effect on primary national radiometric scales are discussed.

  13. Long term response stability of a well-type ionization chamber used in calibration of high dose rate brachytherapy sources

    PubMed Central

    Vandana, S.; Sharma, S. D.

    2010-01-01

    Well-type ionization chamber is often used to measure strength of brachytherapy sources. This study aims to check long term response stability of High Dose Rate (HDR)-1000 Plus well-type ionization chamber in terms of reference air kerma rate (RAKR) of a reference 137Cs brachytherapy source and recommend an optimum frequency of recalibration. An HDR-1000 Plus well-type ionization chamber, a reference 137Cs brachytherapy source (CDCSJ5), and a MAX-4000 electrometer were used in this study. The HDR-1000 Plus well-type chamber was calibrated in terms of reference air kerma rate by the Standards Laboratory of the International Atomic Energy Agency (IAEA), Vienna. The response of the chamber was verified at regular intervals over a period of eight years using the reference 137Cs source. All required correction factors were applied in the calculation of the RAKR of the 137Cs source. This study reveals that the response of the HDR-1000 Plus well-type chamber was well within ±0.5% for about three years after calibration/recalibration. However, it shows deviations larger than ±0.5% after three years of calibration/recalibration and the maximum variation in response of the chamber during an eight year period was 1.71%. The optimum frequency of recalibration of a high dose rate well-type chamber should be three years. PMID:20589119

  14. Long term response stability of a well-type ionization chamber used in calibration of high dose rate brachytherapy sources.

    PubMed

    Vandana, S; Sharma, S D

    2010-04-01

    Well-type ionization chamber is often used to measure strength of brachytherapy sources. This study aims to check long term response stability of High Dose Rate (HDR)-1000 Plus well-type ionization chamber in terms of reference air kerma rate (RAKR) of a reference (137)Cs brachytherapy source and recommend an optimum frequency of recalibration. An HDR-1000 Plus well-type ionization chamber, a reference (137)Cs brachytherapy source (CDCSJ5), and a MAX-4000 electrometer were used in this study. The HDR-1000 Plus well-type chamber was calibrated in terms of reference air kerma rate by the Standards Laboratory of the International Atomic Energy Agency (IAEA), Vienna. The response of the chamber was verified at regular intervals over a period of eight years using the reference (137)Cs source. All required correction factors were applied in the calculation of the RAKR of the (137)Cs source. This study reveals that the response of the HDR-1000 Plus well-type chamber was well within +/-0.5% for about three years after calibration/recalibration. However, it shows deviations larger than +/-0.5% after three years of calibration/recalibration and the maximum variation in response of the chamber during an eight year period was 1.71%. The optimum frequency of recalibration of a high dose rate well-type chamber should be three years.

  15. Ka-Band Monopulse Antenna Pointing Calibration Using Wideband Radio Sources

    NASA Astrophysics Data System (ADS)

    Buu, C.; Calvo, J.; Cheng, T.-H.; Vazquez, M.

    2010-08-01

    A new method of performing a system end-to-end monopulse antenna calibration using widely available wideband astronomical radio sources is presented as an alternative to the current method of using a spacecraft signal. Current monopulse calibration requires a spacecraft carrier signal to measure amplitude and phase differences in the monopulse feed and low-noise amplifiers (LNAs). The alternative method presented here will allow the ground station to perform monopulse calibrations during maintenance periods instead of spacecraft track time, and provide an end-to-end system check-out capability without requiring a spacecraft signal. In this article, we give an overview of the current calibration approach, describe a new method for calibrating with radio sources, and present results from field testing of this new method.

  16. On-sky calibration performance of a monolithic Michelson interferometer filtered source

    NASA Astrophysics Data System (ADS)

    Ge, Jian; Ma, Bo; Powell, Scott; Varosi, Frank; Schofield, Sidney; Grieves, Nolan; Liu, Jian

    2014-07-01

    In the new era of searching for Earth-like planets, new generation radial velocity (RV) high resolution spectrographs requires ~0.1 m/s Doppler calibration accuracy in the visible band and a similar calibration precision in the near infrared. The patented stable monolithic Michelson interferometer filtered source called the Sine source emerges as a very promising calibration device. This Sine source has the potential of covering the practical working wavelengths (~0.38- 2.5 μm) for Doppler measurements with high resolution optical and near infrared high resolution spectrographs at the ground-based telescopes. The single frame calibration precision can reach < 0.1 m/s for the state of the art spectrographs, and it can be easily designed to match the intrinsic sensitivities of future Doppler instruments. The Sine source also has the great practical advantages in compact (portable) size and low cost. Here we report early results from on-sky calibration of a Sine source measured with two state-of-the-art TOU optical high resolution spectrograph (R=100,000, 0.38-0.9 microns) and FIRST near infrared spectrograph (R=50,000, 0.8-1.8 microns) at a 2 meter robotic telescope at Fairborn Observatory in Arizona. The results with the TOU spectrograph monitoring over seven days show that the Sine source has produced ~3 times better calibration precision than the ThAr calibration (RMS = 2.7m/s vs. 7.4m/s) at 0.49-0.62 microns where calibration data have been processed by our preliminary data pipeline and ~1.4 times better than the iodine absorption spectra (RMS=3.6 m/s) at the same wavelength region. As both ThAr and Iodine have reached sub m/s calibration accuracy with existing Doppler instruments (such as HARPS and HIRES), it is likely that the sine source would provide similar improvement once a better data pipeline and an upgraded version of a Sine source are developed. It is totally possible to reach ~0.1 m/s in the optical wavelength region. In addition, this Sine source

  17. Spectral calibration of radiometric detectors using tunable laser sources.

    PubMed

    Schuster, Michaela; Nevas, Saulius; Sperling, Armin; Völker, Stephan

    2012-04-20

    This paper describes the analysis of laser-based responsivity measurements using the Tunable Lasers in Photometry setup at the Physikalisch-Technische Bundesanstalt. An approach based on digital signal analysis is proposed to remove interference-caused oscillations in highly resolved spectral data from laser-based measurements, yielding an improved reproducibility and comparability of results. Digital filters are used to selectively suppress the frequency components of interference fringes visible in the measurement data. We describe the algorithm used and discuss the associated uncertainty components of laser-based measurements. Finally, we give examples of the calibration of different detectors with and without interference effects.

  18. Analysis of Reference Sources for the Characterization and Calibration of Infrared Cameras

    NASA Astrophysics Data System (ADS)

    Gutschwager, B.; Taubert, D.; Hollandt, J.

    2015-03-01

    This paper gives an analysis of the radiometric properties of different types of reference sources applied for the characterization and calibration of infrared cameras. For the absolute radiance measurement with an infrared camera, a metrological characterization and calibration of the instrument are essential. Similar to the calibration of radiation thermometers, this calibration is generally performed with reference sources of known radiance. As infrared cameras are optically and electronically more complex than radiation thermometers, which are equipped with a single element detector, the applied reference sources have to be carefully characterized and limitations in their performance have to be considered. Each pixel of the image measured with an infrared camera should depict correctly the desired physical quantity value of the projected object area. This should be achieved for all relevant conditions of observation, e.g., at different distances or at different incident angles. The performance of cavity radiators and plate radiators is analyzed based on ray-tracing calculations and spatially and angularly resolved radiance measurements with radiation thermometers and cameras. Relevant components of a calibration facility for infrared cameras at PTB are presented with their specifications. A first analysis of the relevant characteristics of the applied infrared calibration sources and infrared cameras is presented as the essential basic information for the realization of the calibration of infrared cameras.

  19. Power source evaluation capabilities at Sandia National Laboratories

    SciTech Connect

    Doughty, D.H.; Butler, P.C.

    1996-04-01

    Sandia National Laboratories maintains one of the most comprehensive power source characterization facilities in the U.S. National Laboratory system. This paper describes the capabilities for evaluation of fuel cell technologies. The facility has a rechargeable battery test laboratory and a test area for performing nondestructive and functional computer-controlled testing of cells and batteries.

  20. Study of neutron scattering contribution on Hp(10) and H*(10) calibration in the Brazilian National Low Scattering Laboratory.

    PubMed

    Freitas, B M; Pereira, W W; Patrão, K C S; Fonseca, E S; Mauricio, C L P

    2014-10-01

    The neutron scattering at the Low Scattering Laboratory of the Brazilian National Neutron Laboratory has been studied using three different methods. The measurements have been done with a traceable standard (241)Am-Be from source-to-detector distances of 0.52-3.00 m. The obtained results with the variation distance methods are in agreement. Measurements with a large shadow cone are not worth for larger distances due to overshadowing. As the quantity required in a calibration is the response of the device being calibrated to the scattered neutron component in order to subtract this from the total response, for these purposes, the distance variation method must be used for each device. To quantify absolutely the scattering contribution on the quantity rates of fluence, Hp(10) and H*(10) in irradiation procedures, a Bonner sphere spectrometer with the shadow cone was employed. The evaluated scattering correction factor value may be employed for a distance of 1.00 m. PMID:24984874

  1. Laboratory robotics -- An automated tool for preparing ion chromatography calibration standards

    SciTech Connect

    Chadwick, J.L.

    1995-04-01

    This paper describes the use of a laboratory robot as an automated tool for preparing multi-level calibration standards for On-Line Ion Chromatography (IC) Systems. The robot is designed for preparation of up to six levels of standards, with each level containing up to eleven ionic species in aqueous solution. The robot is required to add the standards` constituents as both a liquid and solid additions and to keep a record of exactly what goes into making up every standard. Utilizing a laboratory robot to prepare calibration standards provides significant benefits to the testing environment. These benefits include: accurate and precise calibration standards in individually capped containers with preparation traceability; automated and unattended multi-specie preparation for both anion and cation analytical channels; the ability to free up a test operator from a repetitive routine and re-apply those efforts to test operations; The robot uses a single channel IC to analyze each prepared standard for specie content and concentration. Those results are later used as a measure of quality control. System requirements and configurations, robotic operations, manpower requirements, analytical verification, accuracy and precision of prepared solutions, and robotic downtime are discussed in detail.

  2. Development of a low energy ion source for ROSINA ion mode calibration

    SciTech Connect

    Rubin, Martin; Altwegg, Kathrin; Jaeckel, Annette; Balsiger, Hans

    2006-10-15

    The European Rosetta mission on its way to comet 67P/Churyumov-Gerasimenko will remain for more than a year in the close vicinity (1 km) of the comet. The two ROSINA mass spectrometers on board Rosetta are designed to analyze the neutral and ionized volatile components of the cometary coma. However, the relative velocity between the comet and the spacecraft will be minimal and also the velocity of the outgassing particles is below 1 km/s. This combination leads to very low ion energies in the surrounding plasma of the comet, typically below 20 eV. Additionally, the spacecraft may charge up to a few volts in this environment. In order to simulate such plasma and to calibrate the mass spectrometers, a source for ions with very low energies had to be developed for the use in the laboratory together with the different gases expected at the comet. In this paper we present the design of this ion source and we discuss the physical parameters of the ion beam like sensitivity, energy distribution, and beam shape. Finally, we show the first ion measurements that have been performed together with one of the two mass spectrometers.

  3. High precision digital control LED spot light source used to calibrate camera

    NASA Astrophysics Data System (ADS)

    Du, Boyu; Xu, Xiping; Liu, Yang

    2015-04-01

    This paper introduces a method of using LED point light source as the camera calibration light. According to the characteristics of the LED point light source, the constant current source is used to provide the necessary current and the illuminometer is used to measure the luminance of the LED point light source. The constant current source is controlled by ARM MCU and exchange data with the host computer though the mode of serial communications. The PC is used as the host computer, it adjust the current according to the luminance of the LED point light source until the luminance achieve the anticipated value. By experimental analysis, we found that the LED point light source can achieve the desired requirements as the calibration light source, and the accuracy is quite better that achieve the desired effect and it can adaptive control the luminance of LED well. The system is convenient and flexible, and its performance is stable and reliable.

  4. A Bayesian approach to calibrating apatite fission track annealing models for laboratory and geological timescales

    NASA Astrophysics Data System (ADS)

    Stephenson, John; Gallagher, Kerry; Holmes, Chris

    2006-10-01

    We present a new approach for modelling annealing of fission tracks in apatite, aiming to address various problems with existing models. We cast the model in a fully Bayesian context, which allows us explicitly to deal with data and parameter uncertainties and correlations, and also to deal with the predictive uncertainties. We focus on a well-known annealing algorithm [Laslett, G.M., Green, P.F., Duddy, I.R., Gleadow. A.J.W., 1987. Thermal annealing of fission tracks in apatite. 2. A quantitative-analysis. Chem. Geol., 65 (1), 1-13], and build a hierachical Bayesian model to incorporate both laboratory and geological timescale data as direct constraints. Relative to the original model calibration, we find a better (in terms of likelihood) model conditioned just on the reported laboratory data. We then include the uncertainty on the temperatures recorded during the laboratory annealing experiments. We again find a better model, but the predictive uncertainty when extrapolated to geological timescales is increased due to the uncertainty on the laboratory temperatures. Finally, we explictly include a data set [Vrolijk, P., Donelick, R.A., Quenq, J., Cloos. M., 1992. Testing models of fission track annealing in apatite in a simple thermal setting: site 800, leg 129. In: Larson, R., Lancelet, Y. (Eds.), Proceedings of the Ocean Drilling Program, Scientific Results, vol. 129, pp. 169-176] which provides low-temperature geological timescale constraints for the model calibration. When combined with the laboratory data, we find a model which satisfies both the low-temperature and high-temperature geological timescale benchmarks, although the fit to the original laboratory data is degraded. However, when extrapolated to geological timescales, this combined model significantly reduces the well-known rapid recent cooling artifact found in many published thermal models for geological samples.

  5. Photometric Calibration of an EUV Flat Field Spectrometer at the Advanced Light Source

    SciTech Connect

    May, M; Lepson, J; Beiersdorfer, P; Thorn, D; Chen, H; Hey, D; Smith, A

    2002-07-03

    The photometric calibration of ail extreme ultraviolet flat field spectrometer has been done at the Advanced Light Source at LBNL. This spectrometer is used to record spectrum for atomic physics research from highly charged ions in plasmas created in the Livermore electron beam ion traps EBIT-I and SUPEREBIT. Two calibrations were done each with a different gold-coated grating, a 1200 {ell}/mm and a 2400 {ell}/mm, that covered 75-300{angstrom} and 15-160{angstrom}, respectively. The detector for this calibration was a back thinned CCD. The relative calibration was determined for several different incident angles for both gratings. Within the scatter of the data, the calibration was roughly insensitive to the incidence angle for the range of angles investigated.

  6. [Research on the non-source temperature calibration of Multispectral pyrometer].

    PubMed

    Sun, Xiao-gang; Sun, Kun; Dai, Jing-min

    2012-01-01

    At present, Multispectral pyrometer used in high-temperature measurement has already had high resolution and high signal to noise ratio. However, the non-source temperature (higher than 3 000 degrees C) calibration falls far behind the development of multispectral pyrometer and has already seriously hindered the precision and application range of the pyrometer. In order to break through the limitation of calibration of non-source temperature, a new calibration method was put forward in the present paper. The temperature-voltage (T-U) model was formed based on power function where output voltage U of the multispectral pyrometer was derived from its corresponding known temperature point. Based on the model, derivative least square method was used to obtain the parameters of the model to realize the non-source temperature calibration. Both theoretical and experimental data proved the efficiency and precision of the calibration method. In addition, within the spectral range of high-temperature measurement pyrometer (0.4-1.1 microm), the range of non-source temperature calibration with precision better than 3 per thousand, 1% and 3% respectively have been divided theoretically. PMID:22497175

  7. Toward Improvements in Inter-laboratory Calibration of Argon Isotope Measurements

    NASA Astrophysics Data System (ADS)

    Hemming, S. R.; Deino, A. L.; Heizler, M. T.; Hodges, K. V.; McIntosh, W. C.; Renne, P. R.; Swisher, C. C., III; Turrin, B. D.; Van Soest, M. C.

    2015-12-01

    It is important to continue to develop strategies to improve our ability to compare results between laboratories chronometers. The U-Pb community has significantly reduced inter-laboratory biases with the application of a community tracer solution and the distribution of synthetic zircon solutions. Inevitably sample selection and processing and even biases in interpretations will still lead to some disagreements in the assignment of ages. Accordingly natural samples that are shared will be important for achievement of the highest levels of agreement. Analogous improvements in quality and inter-laboratory agreement of analytical aspects of Ar-Ar can be achieved through development of synthetic age standards in gas canisters with multiple pipettes to deliver various controlled amounts of argon to the mass spectrometer. A preliminary proof-of concept comes from the inter-laboratory calibration experiment for the 40Ar/39Ar community. This portable Argon Pipette Intercalibration System (APIS) consists of three 2.7 L canisters each equipped with three pipettes of 0.1, 0.2 and 0.4 cc volumes. The currently traveling APIS has the three canisters filled with air and 40Ar*/39Ar of 1.73 and canister 2 has a 40Ar*/39Ar of 40.98 (~ Alder Creek and Fish Canyon in the same irradiation). With these pipettes it is possible to combine them to provide 0.1, 0.2, 0.3 (0.1+0.2), 0.4, 0.5 (0.1+0.4), 0.6 (0.2+0.4), and 0.7 (0.1+0.2+0.4) cc. The configuration allows a simple test for inter-laboratory biases and for volume/pressure dependent mass fractionation on the measured ratios for a gas with a single argon isotope composition. Although not yet tested, it is also possible to mix gas from any one of the three canisters in proportions of these increments, allowing even more tightly controlled calibration of measurements. We suggest that ultimately each EARTHTIME lab should be equipped with such a system permanently, with a community plan for a traveling system to periodically repeat the

  8. 10 CFR 31.8 - Americium-241 and radium-226 in the form of calibration or reference sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Americium-241 and radium-226 in the form of calibration or... BYPRODUCT MATERIAL § 31.8 Americium-241 and radium-226 in the form of calibration or reference sources. (a..., americium-241 or radium-226 in the form of calibration or reference sources: (1) Any person in a...

  9. 10 CFR 31.8 - Americium-241 and radium-226 in the form of calibration or reference sources.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Americium-241 and radium-226 in the form of calibration or... BYPRODUCT MATERIAL § 31.8 Americium-241 and radium-226 in the form of calibration or reference sources. (a..., americium-241 or radium-226 in the form of calibration or reference sources: (1) Any person in a...

  10. 10 CFR 31.8 - Americium-241 and radium-226 in the form of calibration or reference sources.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Americium-241 and radium-226 in the form of calibration or... BYPRODUCT MATERIAL § 31.8 Americium-241 and radium-226 in the form of calibration or reference sources. (a..., americium-241 or radium-226 in the form of calibration or reference sources: (1) Any person in a...

  11. 10 CFR 31.8 - Americium-241 and radium-226 in the form of calibration or reference sources.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Americium-241 and radium-226 in the form of calibration or... BYPRODUCT MATERIAL § 31.8 Americium-241 and radium-226 in the form of calibration or reference sources. (a..., americium-241 or radium-226 in the form of calibration or reference sources: (1) Any person in a...

  12. 10 CFR 31.8 - Americium-241 and radium-226 in the form of calibration or reference sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Americium-241 and radium-226 in the form of calibration or... BYPRODUCT MATERIAL § 31.8 Americium-241 and radium-226 in the form of calibration or reference sources. (a..., americium-241 or radium-226 in the form of calibration or reference sources: (1) Any person in a...

  13. Mathematical efficiency calibration with uncertain source geometries using smart optimization

    SciTech Connect

    Menaa, N.; Mirolo, L.

    2011-07-01

    The In Situ Object Counting Software (ISOCS), a mathematical method developed by CANBERRA, is a well established technique for computing High Purity Germanium (HPGe) detector efficiencies for a wide variety of source shapes and sizes. In the ISOCS method, the user needs to input the geometry related parameters such as: the source dimensions, matrix composition and density, along with the source-to-detector distance. In many applications, the source dimensions, the matrix material and density may not be well known. Under such circumstances, the efficiencies may not be very accurate since the modeled source geometry may not be very representative of the measured geometry. CANBERRA developed an efficiency optimization software known as 'Advanced ISOCS' that varies the not well known parameters within user specified intervals and determines the optimal efficiency shape and magnitude based on available benchmarks in the measured spectra. The benchmarks could be results from isotopic codes such as MGAU, MGA, IGA, or FRAM, activities from multi-line nuclides, and multiple counts of the same item taken in different geometries (from the side, bottom, top etc). The efficiency optimization is carried out using either a random search based on standard probability distributions, or using numerical techniques that carry out a more directed (referred to as 'smart' in this paper) search. Measurements were carried out using representative source geometries and radionuclide distributions. The radionuclide activities were determined using the optimum efficiency and compared against the true activities. The 'Advanced ISOCS' method has many applications among which are: Safeguards, Decommissioning and Decontamination, Non-Destructive Assay systems and Nuclear reactor outages maintenance. (authors)

  14. 10 CFR 35.65 - Authorization for calibration, transmission, and reference sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... under § 32.74 of this chapter or equivalent Agreement State regulations. (b) Sealed sources, not... sources. 35.65 Section 35.65 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL General Technical Requirements § 35.65 Authorization for calibration, transmission, and reference...

  15. Runoff estimates across large regions using multiple data sources and regional model calibration schemes

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Wang, B.; Vaze, J.; Chiew, F. H.; Guerschman, J. P.; McVicar, T.

    2012-12-01

    Estimating runoff in ungauged or poorly gauged catchments is one of the most challenging tasks in surface water hydrology. This study focuses on runoff estimates across large regions using multiple data sources together with different regional model calibration schemes. First, 228 gauged catchments widely located across south-east Australia (~1.4 million km2) are selected. Half of the catchments are randomly selected for regional model calibrations and the remainder used for cross-validations. Four rainfall-runoff and landscape hydrological models (Xinanjiang, AWBM, Sacramento and AWRA-L) are regionally calibrated against multiple data sources, including recorded daily streamflow, gridded monthly remotely-sensed actual evapotranspiration (ETa) and gridded daily remotely-sensed soil moisture (SM) data. The modeling results are assessed against recorded streamflow, remotely sensed ETa and remotely-sensed SM in other half of the catchments. Results indicate that the multi-objective calibrations are better than the traditional model calibration solely against streamflow data, in terms of overall model performance in simulating daily runoff, monthly actual ET and daily SM in the validation catchments. The runoff prediction results using the regional model calibration schemes perform similarly to (or slightly better than) the traditional regionalization approach, i.e., the nearest neighbor (or spatial proximity) approach. However, the regional model calibration approach has an important advantage for runoff estimates across large regions where gauging stations are relatively sparse.

  16. Calibration of time of flight detectors using laser-driven neutron source

    SciTech Connect

    Mirfayzi, S. R.; Kar, S. Ahmed, H.; Green, A.; Alejo, A.; Jung, D.; Krygier, A. G.; Freeman, R. R.; Clarke, R.; Fuchs, J.; Vassura, L.; Kleinschmidt, A.; Roth, M.; Morrison, J. T.; Najmudin, Z.; Nakamura, H.; Norreys, P.; Oliver, M.; Zepf, M.; Borghesi, M.

    2015-07-15

    Calibration of three scintillators (EJ232Q, BC422Q, and EJ410) in a time-of-flight arrangement using a laser drive-neutron source is presented. The three plastic scintillator detectors were calibrated with gamma insensitive bubble detector spectrometers, which were absolutely calibrated over a wide range of neutron energies ranging from sub-MeV to 20 MeV. A typical set of data obtained simultaneously by the detectors is shown, measuring the neutron spectrum emitted from a petawatt laser irradiated thin foil.

  17. Calibration of time of flight detectors using laser-driven neutron source.

    PubMed

    Mirfayzi, S R; Kar, S; Ahmed, H; Krygier, A G; Green, A; Alejo, A; Clarke, R; Freeman, R R; Fuchs, J; Jung, D; Kleinschmidt, A; Morrison, J T; Najmudin, Z; Nakamura, H; Norreys, P; Oliver, M; Roth, M; Vassura, L; Zepf, M; Borghesi, M

    2015-07-01

    Calibration of three scintillators (EJ232Q, BC422Q, and EJ410) in a time-of-flight arrangement using a laser drive-neutron source is presented. The three plastic scintillator detectors were calibrated with gamma insensitive bubble detector spectrometers, which were absolutely calibrated over a wide range of neutron energies ranging from sub-MeV to 20 MeV. A typical set of data obtained simultaneously by the detectors is shown, measuring the neutron spectrum emitted from a petawatt laser irradiated thin foil. PMID:26233373

  18. High-Precision Calibration of Electron Beam Energy from the Hefei Light Source Using Spin Resonant Depolarization

    NASA Astrophysics Data System (ADS)

    Lan, Jie-Qin; Xu, Hong-Liang

    2014-12-01

    The electron beam energy at the Hefei Light Source (HLS) in the National Synchrotron Radiation Laboratory is highly precisely calibrated by using the method of spin resonant depolarization for the first time. The spin tune and the beam energy are determined by sweeping the frequency of a radial rf stripline oscillating magnetic field to artificially excite a spin resonance and depolarize the beam. The resonance signal is recognized by observing the sudden change of the Touschek loss counting rate of the beam. The possible systematic errors of the experiment are presented and the accuracy of the calibrated energy is shown to be about 10-4. A series of measurements show that the energy stability of the machine is of the order of 9 × 10-3.

  19. Augmenting watershed model calibration with incorporation of ancillary data sources and qualitative soft data sources

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Watershed simulation models can be calibrated using “hard data” such as temporal streamflow observations; however, users may find upon examination of detailed outputs that some of the calibrated models may not reflect summative actual watershed behavior. Thus, it is necessary to use “soft data” (i....

  20. Dosimetric calibration of solid state detectors with low energy β sources

    NASA Astrophysics Data System (ADS)

    Fidanzio, Andrea; Pia Toni, Maria; Capote, Roberto; Pena, Juan; Pasciuti, Katia; Bovi, Maurizio; Perrone, Franco; Azario, Luigi; Lazzeri, Mauro; Gaudino, Diego; Piermattei, Angelo

    2008-01-01

    A PTW Optidos plastic scintillation and a PTW natural diamond detectors were calibrated in terms of absorbed dose to water with β fields produced by 90Sr + 90Y and 85Kr reference sources. Each source was characterized at the Italian National Metrological Institute - the Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti of ENEA (ENEA-INMRI) - for two different series, 1 and 2, of ISO reference β-particle radiation fields. Beam flattening filters were used for the series 1 β fields to give uniform absorbed dose rates over a large area at a source-to-reference plane distance of 30 cm. The series 2 β fields were produced at source-to-reference plane distance of 10 cm, without the beam flattening filters, in order to obtain higher absorbed dose rates. The reference absorbed dose rate values were directly determined by the Italian national standard for β-particle dosimetry (a PTW extrapolation ionization chamber) for the series 1 β fields and by a calibrated transfer standard chamber, (a Capintec thin fixed-volume parallel plate ionization chamber) for the series 2 β fields. Finally the two solid state detectors were calibrated in terms of absorbed dose to water with the series 2 β field. The expanded uncertainties of the calibration coefficients obtained for the plastic scintillation dosimeter were 10% and 12% (2SD) for the 90Sr + 90Y and the 85Kr sources, respectively. The expanded uncertainties obtained for the diamond dosimeter were 10% (2SD) and 16% (2SD) for the 90Sr + 90Y and the 85Kr sources, respectively. The good results obtained with the 90Sr + 90Y and the 85Kr β sources encourage to implement this procedure to calibrate this type of detectors at shorter distances and with other β sources of interest in brachytherapy, for example the 106Ru source.

  1. Wideband spherically focused PVDF acoustic sources for calibration of ultrasound hydrophone probes.

    PubMed

    Selfridge, A; Lewin, P A

    2000-01-01

    Several broadband sources have been developed for the purpose of calibrating hydrophones. The specific configuration described is intended for the calibration of hydrophones In a frequency range of 1 to 40 MHz. All devices used 25 /spl mu/m film of PVDF bonded to a matched backing. Two had radii of curvatures (ROC) of 25.4 and 127 mm with f numbers of 3.8 and 19, respectively. Their active element diameter was 0.28 in (6.60 mm). The active diameter of the third source used was 25 mm, and it had an ROC of 254 mm and an f number of 10. The use of a focused element minimized frequency-dependent diffraction effects, resulting in a smooth variation of acoustic pressure at the focus from 1 to 40 MHz. Also, using a focused PVDF source permitted calibrations above 20 MHz without resorting to harmonic generation via nonlinear propagation. PMID:18238683

  2. Radioactive target and source development at Argonne National Laboratory

    SciTech Connect

    Greene, J.P.; Ahmad, I.; Thomas, G.E.

    1992-01-01

    An increased demand for low-level radioactive targets has created the need for a laboratory dedicated to the production of these foils. A description is given of the radioactive target produced as well as source development work being performed at the Physics Division target facility of Argonne National Laboratory (ANL). Highlights include equipment used and the techniques employed. In addition, some examples of recent source preparation are given as well as work currently in progress.

  3. Radioactive target and source development at Argonne National Laboratory

    SciTech Connect

    Greene, J.P.; Ahmad, I.; Thomas, G.E.

    1992-10-01

    An increased demand for low-level radioactive targets has created the need for a laboratory dedicated to the production of these foils. A description is given of the radioactive target produced as well as source development work being performed at the Physics Division target facility of Argonne National Laboratory (ANL). Highlights include equipment used and the techniques employed. In addition, some examples of recent source preparation are given as well as work currently in progress.

  4. Environmental Assessment for install calibration laboratory, Building 12-52B, Pantex Plant, Amarillo, Texas

    SciTech Connect

    Not Available

    1991-10-01

    This Environmental Assessment (EA) has been prepared pursuant to implementing regulations to the National Environmental Policy Act (NEPA), which requires federal agencies to assess the environmental impacts of a proposed action to determine whether that action requires the preparation of an Environmental Impact Statement (EIS) or if a Finding of No Significant Impact (FONSI) can be issued. NEPA requires that an EA provide an interdisciplinary review of the proposed action in order to identify possible preferable alternatives and to identify mitigative measures that will prevent environmental impacts. If it is determined that the proposed action will have unavoidable significant environmental impact, then an EIS shall be prepared. The proposed project is for design and installation of a self-contained Modular Gage Calibration Laboratory in Building 12-52B at Pantex Plant, Amarillo, Texas. The operating contractor of Pantex Plant has been directed by the Sandia Laboratory at Albuquerque to acquire facilities capable of close temperature and humidity control for calibration of gages and tooling in support of production operations for weapons programs.

  5. Radiometric calibration of SUMER: refinement of the laboratory results under operational conditions on SOHO.

    PubMed

    Wilhelm, K; Lemaire, P; Feldman, U; Hollandt, J; Schühle, U; Curdt, W

    1997-09-01

    The radiometric calibration of the solar telescope and spectrometer SUMER was carried out in the laboratory before delivery of the instrument for integration into the SOHO (Solar and Heliospheric Observatory) spacecraft. Although this effort led to a reasonable coverage of the wavelength range from 53.70 to 146.96 nm, uncalibrated portions of the sensitivity curves remained before SUMER became operational in early 1996. Thereafter it was possible to perform extrapolations and interpolations of the calibration curves of detector A to shorter, longer, and intermediate wavelengths by using emission line pairs with known intensity ratios. The spectra of the stars alpha and rho Leonis were also observed on the KBr (potassium bromide) photocathode and the bare microchannel plate (MCP) in the range from 120 to 158 nm. In addition, the sensitivity ratios of the KBr photocathode to the bare MCP were determined for many solar lines as well as the H i Lyman and the thermal continua. The results have been found to be consistent with published laboratory data. The uncertainty is +/-15% (1 varsigma) in the wavelength range from 54 to 125 nm.

  6. RadBall™ Technology Testing in the Savannah River Site’s Health Physics Instrument Calibration Laboratory

    PubMed Central

    Farfán, Eduardo B.; Foley, Trevor Q.; Jannik, G. Timothy; Harpring, Larry J.; Gordon, John R.; Blessing, Ronald; Coleman, J. Rusty; Holmes, Christopher J.; Oldham, Mark; Adamovics, John; Stanley, Steven J.

    2010-01-01

    The United Kingdom’s National Nuclear Laboratory (NNL) has developed a radiation-mapping device that can locate and quantify radioactive hazards within contaminated areas of the nuclear industry. The device, known as RadBall™, consists of a colander-like outer collimator that houses a radiation-sensitive polymer sphere. The collimator has over two hundred small holes; thus, specific areas of the polymer sphere are exposed to radiation becoming increasingly more opaque in proportion to the absorbed dose. The polymer sphere is imaged in an optical-CT scanner that produces a high resolution 3D map of optical attenuation coefficients. Subsequent analysis of the optical attenuation data provides information on the spatial distribution of sources in a given area forming a 3D characterization of the area of interest. The RadBall™ technology has been deployed in a number of technology trials in nuclear waste reprocessing plants at Sellafield in the United Kingdom and facilities of the Savannah River National Laboratory (SRNL). This paper summarizes the tests completed at SRNL Health Physics Instrument Calibration Laboratory (HPICL). PMID:21617738

  7. Isotherm Sensor Calibration Program for Mars Science Laboratory Heat Shield Flight Data Analysis

    NASA Technical Reports Server (NTRS)

    Santos, Jose A.; Oishi, Tomo; Martinez, Ed R.

    2011-01-01

    Seven instrumented sensor plugs were installed on the Mars Science Laboratory heat shield in December 2008 as part of the Mars Science Laboratory Entry, Descent, and Landing Instrumentation (MEDLI) project. These sensor plugs contain four in-depth thermocouples and one Hollow aErothermal Ablation and Temperature (HEAT) sensor. The HEAT sensor follows the time progression of a 700 C isotherm through the thickness of a thermal protection system (TPS) material. The data can be used to infer char depth and, when analyzed in conjunction with the thermocouple data, the thermal gradient through the TPS material can also be determined. However, the uncertainty on the isotherm value is not well defined. To address this uncertainty, a team at NASA Ames Research Center is carrying out a HEAT sensor calibration test program. The scope of this test program is described, and initial results from experiments conducted in the laboratory to study the isotherm temperature of the HEAT sensor are presented. Data from the laboratory tests indicate an isotherm temperature of 720 C 60 C. An overview of near term arc jet testing is also given, including preliminary data from 30.48cm 30.48cm PICA panels instrumented with two MEDLI sensor plugs and tested in the NASA Ames Panel Test Facility. Forward work includes analysis of the arc jet test data, including an evaluation of the isotherm value based on the instant in time when it reaches a thermocouple depth.

  8. Crowd-Sourced Calibration: The GEDI Strategy for Empirical Biomass Estimation Using Spaceborne Lidar

    NASA Astrophysics Data System (ADS)

    Dubayah, R.

    2015-12-01

    The central task in estimating forest biomass from spaceborne sensors is the development of calibration equations that relate observed forest structure to biomass at a variety of spatial scales. Empirical methods generally rely on statistical estimation or machine learning techniques where field-based estimates of biomass at the plot level are associated with post-launch observations of variables such as canopy height and cover. For global-scale mapping the process is complex and leads to a number of questions: How many calibrations are required to capture non-stationarity in the relationships? Where does one calibration begin and another end? Should calibrations be conditioned by biome? Vegetation type? Land-use? Post-launch calibrations lead to further complications, such as the requirement to have sufficient field plot data underneath potentially sparse satellite observations, spatial and temporal mismatches in scale between field plots and pixels, and geolocation uncertainty, both in the plots and the satellite data. The Global Ecosystem Dynamics Investigation (GEDI) is under development by NASA to estimate forest biomass. GEDI will deploy a multi-beam lidar on the International Space Station and provide billions of observations of forest structure per year. Because GEDI uses relatively small footprints, about 25 m diameter, post-launch calibration is exceptionally problematic for the reasons listed earlier. Instead, GEDI will use a kind of "crowd-sourced" calibration strategy where existing lidar observations and the corresponding plot biomass will be assembled from data contributed by the science community. Through a process of continuous updating, calibrations will be refined as more data is ingested. This talk will focus on the GEDI pre-launch calibration strategy and present initial progress on its development, and how it forms the basis for meeting mission biomass requirements.

  9. Suppression of fiber modal noise induced radial velocity errors for bright emission-line calibration sources

    SciTech Connect

    Mahadevan, Suvrath; Halverson, Samuel; Ramsey, Lawrence; Venditti, Nick

    2014-05-01

    Modal noise in optical fibers imposes limits on the signal-to-noise ratio (S/N) and velocity precision achievable with the next generation of astronomical spectrographs. This is an increasingly pressing problem for precision radial velocity spectrographs in the near-infrared (NIR) and optical that require both high stability of the observed line profiles and high S/N. Many of these spectrographs plan to use highly coherent emission-line calibration sources like laser frequency combs and Fabry-Perot etalons to achieve precision sufficient to detect terrestrial-mass planets. These high-precision calibration sources often use single-mode fibers or highly coherent sources. Coupling light from single-mode fibers to multi-mode fibers leads to only a very low number of modes being excited, thereby exacerbating the modal noise measured by the spectrograph. We present a commercial off-the-shelf solution that significantly mitigates modal noise at all optical and NIR wavelengths, and which can be applied to spectrograph calibration systems. Our solution uses an integrating sphere in conjunction with a diffuser that is moved rapidly using electrostrictive polymers, and is generally superior to most tested forms of mechanical fiber agitation. We demonstrate a high level of modal noise reduction with a narrow bandwidth 1550 nm laser. Our relatively inexpensive solution immediately enables spectrographs to take advantage of the innate precision of bright state-of-the art calibration sources by removing a major source of systematic noise.

  10. The biochemical estimation of age in Euphausiids: Laboratory calibration and field comparisons

    NASA Astrophysics Data System (ADS)

    Harvey, H. R.; Ju, Se-J.; Son, S.-K.; Feinberg, L. R.; Shaw, C. T.; Peterson, W. T.

    2010-04-01

    Euphausiids play a key role in many marine ecosystems as a link between primary producers and top predators. Understanding their demographic (i.e. age) structure is an essential tool to assess growth and recruitment as well as to determine how changes in environmental conditions might alter their condition and distribution. Age determination of crustaceans cannot be accomplished using traditional approaches, and here we evaluate the potential for biochemical products of tissue metabolism (termed lipofuscins) to determine the demographic structure of euphausiids in field collections . Lipofuscin was extracted from krill neural tissues (eye and eye-stalk), quantified using fluorescent intensity and normalized to tissue protein content to allow comparisons across animal sizes. Multiple fluorescent components from krill were observed, with the major product having a maximum fluorescence at excitation of 355 nm and emission of 510 nm. Needed age calibration of lipofuscin accumulation in Euphausia pacifica was accomplished using known-age individuals hatched and reared in the laboratory for over one year. Lipofuscin content extracted from neural tissues of laboratory-reared animals was highly correlated with the chronological age of animals ( r=0.87). Calibrated with laboratory lipofuscin accumulation rates, field-collected sub-adult and adult E. pacifica in the Northeast Pacific were estimated to be older than 100 days and younger than 1year. Comparative data for the Antarctic krill, E. superba showed much higher lipofuscin values suggesting a much longer lifespan than the more temperate species, E. pacifica. These regional comparisons suggest that biochemical indices allow a practical approach to estimate population age structure of diverse populations, and combined with other measurements can provide estimates of vital rates (i.e. longevity, mortality, growth) for krill populations in dynamic environments.

  11. Precise uniform light source based on optically connected integrating spheres for optical instrument calibration

    NASA Astrophysics Data System (ADS)

    Mikheenko, Leonid; Borovytsky, Volodymyr

    2011-09-01

    The paper proposes the uniform light sources which have a form of several or multiple optically connected integrating spheres. The principal advantages of these light sources are high photometric and metrological characteristics. As a result they have good perspectives in optical radiometry and calibration of imaging systems and optical instruments. The principal field of their application is calibration of remote sensing instruments and sensitive megapixel cameras. The light source contains several (3 ... 11) primary integrating spheres of small diameters which are installed on a secondary integrating sphere of bigger diameter. The initial light sources - halogen lamps or light emitted diodes are installed inside the primary integrating spheres. These spheres are mounted on the secondary integrating sphere. The radiation comes from the primary integrating spheres to the secondary one through diaphragms which diameters can be varied. The secondary integrating sphere has an output aperture where uniform radiance emits. It is investigated the light source design with an output aperture diameter 0.2 m and 3 or 5 primary integrating spheres. It guarantees the output radiance in range from 0.01 to 1000 W/(st•m2), radiance uniformity bigger 99.5% in an output aperture, non-linearity of an output radiance control - smaller 0.1 %. The paper presents the results of theoretical and experimental research of these light sources including the techniques for radiance calculation and the recommendations for light source design. The proposed light sources can be considered as one of the best candidates for calibration of remote sensing instruments working in optical range 0.4 - 2.2 mkm. Key words: integrating sphere, light source, calibration, uniformity, radiance, remote sensing, optical instrument.

  12. VizieR Online Data Catalog: Interferometer phase calibration sources. I (Patnaik+ 1992)

    NASA Astrophysics Data System (ADS)

    Patnaik, A. R.; Browne, I. W. A.; Wilkinson, P. N.; Wrobel, J. M.

    1997-05-01

    We present a catalogue of 800 compact radio sources in the declination range 35deg<δ<75deg whose positions have been measured to an rms accuracy of ~12milliarcsec with the VLA. They are primarily intended for use as phase reference sources for the Jodrell Bank MERLIN but they will also be suitable phase calibrators for the VLA and the VLBI networks. (2 data files).

  13. Sources and assumptions for the vicarious calibration of ocean color satellite observations

    SciTech Connect

    Bailey, Sean W.; Hooker, Stanford B.; Antoine, David; Franz, Bryan A.; Werdell, P. Jeremy

    2008-04-20

    Spaceborne ocean color sensors require vicarious calibration to sea-truth data to achieve accurate water-leaving radiance retrievals. The assumed requirements of an in situ data set necessary to achieve accurate vicarious calibration were set forth in a series of papers and reports developed nearly a decade ago, which were embodied in the development and site location of the Marine Optical BuoY (MOBY). Since that time, NASA has successfully used data collected by MOBY as the sole source of sea-truth data for vicarious calibration of the Sea-viewing Wide field-of-view Sensor (SeaWiFS) and Moderate Resolution Imaging Spectroradiometer instruments. In this paper, we make use of the 10-year, global time series of SeaWiFS measurements to test the sensitivity of vicarious calibration to the assumptions inherent in the in situ requirements (e.g., very low chlorophyll waters, hyperspectral measurements). Our study utilized field measurements from a variety of sources with sufficient diversity in data collection methods and geophysical variability to challenge those in situ restrictions. We found that some requirements could be relaxed without compromising the ability to vicariously calibrate to the level required for accurate water-leaving radiance retrievals from satellite-based sensors.

  14. Characteristics of Cometary Dust Tracks in Stardust Aerogel and Laboratory Calibrations

    NASA Technical Reports Server (NTRS)

    Burchell, M. J.; Fairey, S. A. J.; Wozniakiewicz, P.; Brownlee, D. E.; Hoerz, F.; Kearsley, A. T.; See, T. H.; Tsou, P.; Westphal, A.; Green, S. F.; Trigo-Rodriguez, J. M.; Dominguez, G.

    2007-01-01

    The cometary tray of the NASA Stardust spacecraft s aerogel collector has been examined to study the dust that was captured during the 2004 fly by of comet 81P/Wild-2. An optical scan of the entire collector surface revealed 256 impact features in the aerogel (width > 100 microns). 20 aerogel blocks (out of a total of 132) were removed from the collector tray for a higher resolution optical scan and 186 tracks were observed (track length > 50 microns and width > 8 microns). The impact features were classified into three types based on their morphology. Laboratory calibrations were conducted which reproduce all three types. This work suggests that the cometary dust consisted of some cohesive, relatively strong particles as well as particles with a more friable or low cohesion matrix containing smaller strong grains. The calibrations also permitted a particle size distribution to be estimated for the cometary dust. We estimate that approximately 1200 particles bigger than 1 micron struck the aerogel. The cumulative size distribution of the captured particles was obtained and compared with observations made by active dust detectors during the encounter. At large sizes (>20 microns) all measures of the dust are compatible, but at micrometer scales and smaller discrepancies exist between the various measurement systems which may reflect structure in the dust flux (streams, clusters etc.) along with some possible instrument effects.

  15. An automated calibration laboratory for flight research instrumentation: Requirements and a proposed design approach

    NASA Technical Reports Server (NTRS)

    Oneill-Rood, Nora; Glover, Richard D.

    1990-01-01

    NASA's Dryden Flight Research Facility (Ames-Dryden), operates a diverse fleet of research aircraft which are heavily instrumented to provide both real time data for in-flight monitoring and recorded data for postflight analysis. Ames-Dryden's existing automated calibration (AUTOCAL) laboratory is a computerized facility which tests aircraft sensors to certify accuracy for anticipated harsh flight environments. Recently, a major AUTOCAL lab upgrade was initiated; the goal of this modernization is to enhance productivity and improve configuration management for both software and test data. The new system will have multiple testing stations employing distributed processing linked by a local area network to a centralized database. The baseline requirements for the new AUTOCAL lab and the design approach being taken for its mechanization are described.

  16. Laboratory measurements and a theoretical analysis of the TCT fading channel radio system. [Tone Calibrated Technique

    NASA Technical Reports Server (NTRS)

    Rafferty, William; Anderson, John B.; Saulnier, Gary J.; Holm, John R.

    1987-01-01

    This paper documents the laboratory and theoretical performance of a pilot-aided digital radio system. The technique considered transmits a midband pilot tone to improve the receiver data detection performance in a multipath fading channel and is referred to as the tone calibrated technique (TCT). The performance of a 860 MHz prototype system carrying 2.4 kbit/s data under Rician fading conditions is reported. Both experimental and analytical results show that the error floor experienced with nonpilot-aided transmission methods is effectively removed by the TCT scheme, resulting in significant performance gains at high signal-to-noise ratio values. The paper also examines the TCT system performance under typical operating conditions and presents a new analysis of the TCT theoretical error probability.

  17. Shielding calculations and verifications for the new Radiation Instrument Calibration Facility at Los Alamos National Laboratory

    SciTech Connect

    George, G. L.; Olsher, R. H.; Seagraves, D. T.

    2002-01-01

    MCNP-4C1 was used to perform the shielding design for the new Central Health Physics Calibration Facility (CHPCF) at Los Alamos National Laboratory (LANL). The problem of shielding the facility was subdivided into three separate components: (1) Transmission; (2) Skyshine; and (3) Maze Streaming/ Transmission. When possible, actual measurements were taken to verify calculation results. The comparison of calculation versus measurement results shows excellent agreement for neutron calculations. For photon comparisons, calculations resulted in conservative estimates of the Effective Dose Equivalent (EDE) compared to measured results. This disagreement in the photon measurements versus calculations is most likely due to several conservative assumptions regarding shield density and composition. For example, reinforcing steel bars (Rebar) in the concrete shield walls were not included in the shield model.

  18. Behaviour of mudflows realized in a laboratory apparatus and relative numerical calibration

    NASA Astrophysics Data System (ADS)

    Brezzi, Lorenzo; Gabrieli, Fabio; Kaitna, Roland; Cola, Simonetta

    2016-04-01

    Nowadays, numerical simulations are indispensable allies for the researchers to reproduce phenomena such as earth-flows, debris-flows and mudflows. One of the most difficult and problematic phases is about the choice and the calibration of the parameters to be included in the model at the real scale. Surely, it can be useful to start from laboratory experiment that simplify as much as possible the case study with the aim of reducing uncertainties related to the trigger and the propagation of a real flow. In this way, geometry of the problem, identification of the triggering mass, are well known and constrained in the experimental tests as in the numerical simulations and the focus of the study may be moved to the material parameters. This article wants to analyze the behavior of different mixtures of water and kaolin, which flow in a laboratory channel. A 10 dm3 prismatic container that discharges the material into a channel 2m long and 0.16 m wide composes the simple experimental apparatus. The chute base was roughened by glued sand and inclined with a 21° angle. Initially, we evaluated the lengths of run-out, the spread and shape of the deposit for five different mixtures. A huge quantity of information were obtained by 3 laser sensors attached to the channel and by photogrammetry, that gives out a 3D model of the deposit shape at the end of the flow. Subsequently, we reproduced these physical phenomena by using the numerical model Geoflow-SPH (Pastor et al., 2008; 2014) , governed by a Bingham rheological law (O'Brien & Julien, 1988), and we calibrated the different tests by back-analysis to assess optimum parameters. The final goal was the comprehension of the relationship that characterizes the parameters with the variation of the kaolin content in the mixtures.

  19. Narrow Line X-Ray Calibration Source for High Resolution Microcalorimeters

    NASA Technical Reports Server (NTRS)

    Hokin, M.S.; McCammon, D.; Morgan, K.M.; Bandler, Simon Richard; Lee, S.J.; Moseley, S.H.; Smith, S.J.

    2013-01-01

    We are developing a narrow line calibration source for use with X-ray microcalorimeters. At energies below 300 electronvolts fluorescent lines are intrinsically broad, making calibration of high resolution detectors difficult. This source consists of a 405 nanometers (3 electronvolts) laser diode coupled to an optical fiber. The diode is pulsed to create approximately one hundred photons in a few microseconds. If the pulses are short compared to the rise time of the detector, they will be detected as single events with a total energy in the soft X-ray range. Poisson fluctuations in photon number per pulse create a comb of X-ray lines with 3 electronvolts spacing, so detectors with energy resolution better than 2 electronvolts are required to resolve the individual lines. Our currently unstabilized diode has a multimode width less than 1 nanometer, giving a 300 electronvolt event a Full width at half maximum (FWHM) less than 0.1 electronvolts. By varying the driving voltage, or pulse width, the source can produce a comb centered on a wide range of energies. The calibration events are produced at precisely known times. This allows continuous calibration of a flight mission without contaminating the observed spectrum and with minimal deadtime.

  20. The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) 2005: Calibration and Targeted Sources

    NASA Astrophysics Data System (ADS)

    Truch, M. D. P.; Ade, P. A. R.; Bock, J. J.; Chapin, E. L.; Devlin, M. J.; Dicker, S.; Griffin, M.; Gundersen, J. O.; Halpern, M.; Hargrave, P. C.; Hughes, D. H.; Klein, J.; Marsden, G.; Martin, P. G.; Mauskopf, P.; Netterfield, C. B.; Olmi, L.; Pascale, E.; Patanchon, G.; Rex, M.; Scott, D.; Semisch, C.; Tucker, C.; Tucker, G. S.; Viero, M. P.; Wiebe, D. V.

    2008-07-01

    The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) operated successfully during a 100 hr flight from northern Sweden in 2005 June (BLAST05). As part of the calibration and pointing procedures, several compact sources were mapped, including solar system, Galactic, and extragalactic targets, specifically Pallas, CRL 2688, LDN 1014, IRAS 20126+4104, IRAS 21078+5211, IRAS 21307+5049, IRAS 22134+5834, IRAS 23011+6126, K3-50, W75N, and Mrk 231. One additional source, Arp 220, was observed and used as our primary calibrator. Details of the overall BLAST05 calibration procedure are discussed here. The BLAST observations of each compact source are described, flux densities and spectral energy distributions are reported, and these are compared with previous measurements at other wavelengths. The 250, 350, and 500 μm BLAST data can provide useful constraints to the amplitude and slope of the submillimeter continuum, which in turn may be useful for the improved calibration of other submillimeter instruments.

  1. Metrology laboratory requirements for third-generation synchrotron radiation sources

    SciTech Connect

    Takacs, P.Z.; Quian, Shinan

    1997-11-01

    New third-generation synchrotron radiation sources that are now, or will soon, come on line will need to decide how to handle the testing of optical components delivered for use in their beam lines. In many cases it is desirable to establish an in-house metrology laboratory to do the work. We review the history behind the formation of the Optical Metrology Laboratory at Brookhaven National Laboratory and the rationale for its continued existence. We offer suggestions to those who may be contemplating setting up similar facilities, based on our experiences over the past two decades.

  2. The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) 2005: Calibration and Targeted Sources

    NASA Astrophysics Data System (ADS)

    Truch, Matthew; BLAST Collaboration

    2007-12-01

    The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) operated successfully during a 100-hour flight from northern Sweden in June 2005 (BLAST05). As part of the calibration and pointing procedures, several compact sources were mapped, including solar system, Galactic, and extragalactic targets, specifically Pallas, CRL 2688, LDN 1014, IRAS 20126+4104, IRAS 21078+5211, IRAS 21307+5049, IRAS 22134+5834, IRAS 23011+6126, K3-50, W 75N, Mrk 231, NGC 4565, and Arp 220 (this last source being our primary calibrator). The BLAST observations of each compact source are described, flux densities and spectral energy distributions are reported, and these are compared with previous measurements at other wavelengths. BLAST was particularly useful for constraining the slope of the submillimeter continuum.

  3. Open Source Software Licenses for Livermore National Laboratory

    SciTech Connect

    Busby, L.

    2000-08-10

    This paper attempts to develop supporting material in an effort to provide new options for licensing Laboratory-created software. Where employees and the Lab wish to release software codes as so-called ''Open Source'', they need, at a minimum, new licensing language for their released products. Several open source software licenses are reviewed to understand their common elements, and develop recommendations regarding new language.

  4. Laboratory calibration of the cassini cosmic dust analyser (CDA) using new, low density projectiles

    NASA Astrophysics Data System (ADS)

    Goldsworthy, B. J.; Burchell, M. J.; Cole, M. J.; Green, S. F.; Leese, M. R.; McBride, N.; McDonnell, J. A. M.; Müller, M.; Grün, E.; Srama, R.; Armes, S. P.; Khan, M. A.

    The Cassini Cosmic Dust Analyser (CDA), developed from the Galileo and Ulysses dust instruments with the addition of a Chemical Analyser, is currently travelling outward from the Earth (collecting data from March 1999 onward) to the Saturnian system (arrival 2004) via Jupiter. The Chemical Analyser will provide information on the elemental composition of impacting micrometeoroids through impact ionisation, time-of-flight mass spectrometry. A rigorous calibration programme primarily focussed upon the Chemical Analyser is in progress at the University of Kent at Canterbury. A 2-MV Van de Graaff electrostatic accelerator and CDA laboratory model are used to simulate impacts. Acceleration of revolutionary low density, polymer dust particles has enabled an insight into the response of CDA to molecularly bonded material with increasing event velocity. These conducting polymer coated polystyrene latex particles represent significantly better analogues for carbonaceous cosmic grains than more traditionally accelerated projectiles (e.g. iron) and have enabled complex organic spectra to be produced in the laboratory. The current status of an ongoing programme is reported. Three samples are presented, two polypyrrole coated latexes of differing size and one PEDOT-coated latex sample.

  5. A method for the temperature calibration of an infrared camera using water as a radiative source

    SciTech Connect

    Bower, S. M.; Kou, J.; Saylor, J. R.

    2009-09-15

    Presented here is an effective low-cost method for the temperature calibration of infrared cameras, for applications in the 0-100 deg. C range. The calibration of image gray level intensity to temperature is achieved by imaging an upwelling flow of water, the temperature of which is measured with a thermistor probe. The upwelling flow is created by a diffuser located below the water surface of a constant temperature water bath. The thermistor probe is kept immediately below the surface, and the distance from the diffuser outlet to the surface is adjusted so that the deformation of the water surface on account of the flow is small, yet the difference between the surface temperature seen by the camera and the bulk temperature measured by the thermistor is also small. The benefit of this method compared to typical calibration procedures is that, without sacrificing the quality of the calibration, relatively expensive commercial blackbodies are replaced by water as the radiative source ({epsilon}{approx_equal}0.98 for the wavelengths considered here). A heat transfer analysis is provided, which improves the accuracy of the calibration method and also provides the user with guidance to further increases in accuracy of the method.

  6. ECR Ion Source Developments at the Oak Ridge National Laboratory

    SciTech Connect

    Alton, G.D.; Liu, Y.; Meyer, F.W.

    1998-10-05

    New techniques for enhancing the performances of electron cyclotron resonance (ECR) ion sources are being investigated at the Oak Ridge National Laboratory. We have utilized the multiple discrete frequency technique to improve the charge state distributions extracted from conventional magnetic field geometry ECR source by injecting three frequencies into the source. A new flat central magnetic field concept, has been incorporated in the designs of a compact all-permanent-magnet source for high charge-state ion beam generation and a compact electromagnetic source for singly ionized radioactive ion beam generation for use in the Holifield Radioactive Ion Beam Facility (HRIBF) research program. A review of the three frequency injection experiments and descriptions of the design aspects of the "volume-type" ECR ion sources will be given in this report.

  7. The Science of Calibration

    NASA Astrophysics Data System (ADS)

    Kent, S. M.

    2016-05-01

    This paper presents a broad overview of the many issues involved in calibrating astronomical data, covering the full electromagnetic spectrum from radio waves to gamma rays, and considering both ground-based and space-based missions. These issues include the science drivers for absolute and relative calibration, the physics behind calibration and the mechanisms used to transfer it from the laboratory to an astronomical source, the need for networks of calibrated astronomical standards, and some of the challenges faced by large surveys and missions.

  8. X-ray intensity and source size characterizations for the 25 kV upgraded Manson source at Sandia National Laboratories

    NASA Astrophysics Data System (ADS)

    Loisel, G.; Lake, P.; Gard, P.; Dunham, G.; Nielsen-Weber, L.; Wu, M.; Norris, E.

    2016-11-01

    At Sandia National Laboratories, the x-ray generator Manson source model 5 was upgraded from 10 to 25 kV. The purpose of the upgrade is to drive higher characteristics photon energies with higher throughput. In this work we present characterization studies for the source size and the x-ray intensity when varying the source voltage for a series of K-, L-, and M-shell lines emitted from Al, Y, and Au elements composing the anode. We used a 2-pinhole camera to measure the source size and an energy dispersive detector to monitor the spectral content and intensity of the x-ray source. As the voltage increases, the source size is significantly reduced and line intensity is increased for the three materials. We can take advantage of the smaller source size and higher source throughput to effectively calibrate the suite of Z Pulsed Power Facility crystal spectrometers.

  9. Development of the LUX detector's CH3 T calibration source and ER response

    NASA Astrophysics Data System (ADS)

    Knoche, Richard; LUX Collaboration

    2015-04-01

    The LUX dark matter search experiment is a 350 kg two-phase liquid/gas xenon time projection chamber located at the 4850 ft level of the Sanford Underground Research Facility in Lead, SD. I will discuss the development and deployment of an internal tritium calibration source for use in the LUX dark matter experiment. This source allows us to characterize the electron recoil band, which is the dominant population of background events, throughout the bulk of the LUX detector. It is also useful in determining important detector characteristics such as the fiducial volume and the detector threshold. After calibration is complete we remove the long lived radioisotope from our detector using the results of our R&D efforts.

  10. Non-matrix Matched Glass Disk Calibration Standards Improve XRF Micronutrient Analysis of Wheat Grain across Five Laboratories in India

    PubMed Central

    Guild, Georgia E.; Stangoulis, James C. R.

    2016-01-01

    Within the HarvestPlus program there are many collaborators currently using X-Ray Fluorescence (XRF) spectroscopy to measure Fe and Zn in their target crops. In India, five HarvestPlus wheat collaborators have laboratories that conduct this analysis and their throughput has increased significantly. The benefits of using XRF are its ease of use, minimal sample preparation and high throughput analysis. The lack of commercially available calibration standards has led to a need for alternative calibration arrangements for many of the instruments. Consequently, the majority of instruments have either been installed with an electronic transfer of an original grain calibration set developed by a preferred lab, or a locally supplied calibration. Unfortunately, neither of these methods has been entirely successful. The electronic transfer is unable to account for small variations between the instruments, whereas the use of a locally provided calibration set is heavily reliant on the accuracy of the reference analysis method, which is particularly difficult to achieve when analyzing low levels of micronutrient. Consequently, we have developed a calibration method that uses non-matrix matched glass disks. Here we present the validation of this method and show this calibration approach can improve the reproducibility and accuracy of whole grain wheat analysis on 5 different XRF instruments across the HarvestPlus breeding program. PMID:27375644

  11. Non-matrix Matched Glass Disk Calibration Standards Improve XRF Micronutrient Analysis of Wheat Grain across Five Laboratories in India.

    PubMed

    Guild, Georgia E; Stangoulis, James C R

    2016-01-01

    Within the HarvestPlus program there are many collaborators currently using X-Ray Fluorescence (XRF) spectroscopy to measure Fe and Zn in their target crops. In India, five HarvestPlus wheat collaborators have laboratories that conduct this analysis and their throughput has increased significantly. The benefits of using XRF are its ease of use, minimal sample preparation and high throughput analysis. The lack of commercially available calibration standards has led to a need for alternative calibration arrangements for many of the instruments. Consequently, the majority of instruments have either been installed with an electronic transfer of an original grain calibration set developed by a preferred lab, or a locally supplied calibration. Unfortunately, neither of these methods has been entirely successful. The electronic transfer is unable to account for small variations between the instruments, whereas the use of a locally provided calibration set is heavily reliant on the accuracy of the reference analysis method, which is particularly difficult to achieve when analyzing low levels of micronutrient. Consequently, we have developed a calibration method that uses non-matrix matched glass disks. Here we present the validation of this method and show this calibration approach can improve the reproducibility and accuracy of whole grain wheat analysis on 5 different XRF instruments across the HarvestPlus breeding program. PMID:27375644

  12. Non-matrix Matched Glass Disk Calibration Standards Improve XRF Micronutrient Analysis of Wheat Grain across Five Laboratories in India.

    PubMed

    Guild, Georgia E; Stangoulis, James C R

    2016-01-01

    Within the HarvestPlus program there are many collaborators currently using X-Ray Fluorescence (XRF) spectroscopy to measure Fe and Zn in their target crops. In India, five HarvestPlus wheat collaborators have laboratories that conduct this analysis and their throughput has increased significantly. The benefits of using XRF are its ease of use, minimal sample preparation and high throughput analysis. The lack of commercially available calibration standards has led to a need for alternative calibration arrangements for many of the instruments. Consequently, the majority of instruments have either been installed with an electronic transfer of an original grain calibration set developed by a preferred lab, or a locally supplied calibration. Unfortunately, neither of these methods has been entirely successful. The electronic transfer is unable to account for small variations between the instruments, whereas the use of a locally provided calibration set is heavily reliant on the accuracy of the reference analysis method, which is particularly difficult to achieve when analyzing low levels of micronutrient. Consequently, we have developed a calibration method that uses non-matrix matched glass disks. Here we present the validation of this method and show this calibration approach can improve the reproducibility and accuracy of whole grain wheat analysis on 5 different XRF instruments across the HarvestPlus breeding program.

  13. Simple Penning ion source for laboratory research and development applications.

    PubMed

    Rovey, Joshua L; Ruzic, Brandon P; Houlahan, Thomas J

    2007-10-01

    A simple Penning ion generator (PIG) that can be easily fabricated with simple machining skills and standard laboratory accessories is described. The PIG source uses an iron cathode body, samarium cobalt permanent magnet, stainless steel anode, and iron cathode faceplate to generate a plasma discharge that yields a continuous 1 mA beam of positively charged hydrogen ions at 1 mTorr of pressure. This operating condition requires 5.4 kV and 32.4 W of power. Operation with helium is similar to hydrogen. The ion source is being designed and investigated for use in a sealed-tube neutron generator; however, this ion source is thoroughly described so that it can be easily implemented by other researchers for other laboratory research and development applications.

  14. Comparison of Continuous Wave CO2 Doppler Lidar Calibration Using Earth Surface Targets in Laboratory and Airborne Measurements

    NASA Technical Reports Server (NTRS)

    Jarzembski, Maurice A.; Srivastava, Vandana

    1999-01-01

    Routine backscatter, beta, measurements by an airborne or space-based lidar from designated earth surfaces with known and fairly uniform beta properties can potentially offer lidar calibration opportunities. This can in turn be used to obtain accurate atmospheric aerosol and cloud beta measurements on large spatial scales. This is important because achieving a precise calibration factor for large pulsed lidars then need not rest solely on using a standard hard target procedure. Furthermore, calibration from designated earth surfaces would provide an inflight performance evaluation of the lidar. Hence, with active remote sensing using lasers with high resolution data, calibration of a space-based lidar using earth's surfaces will be extremely useful. The calibration methodology using the earth's surface initially requires measuring beta of various earth surfaces simulated in the laboratory using a focused continuous wave (CW) CO2 Doppler lidar and then use these beta measurements as standards for the earth surface signal from airborne or space-based lidars. Since beta from the earth's surface may be retrieved at different angles of incidence, beta would also need to be measured at various angles of incidences of the different surfaces. In general, Earth-surface reflectance measurements have been made in the infrared, but the use of lidars to characterize them and in turn use of the Earth's surface to calibrate lidars has not been made. The feasibility of this calibration methodology is demonstrated through a comparison of these laboratory measurements with actual earth surface beta retrieved from the same lidar during the NASA/Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) mission on NASA's DC8 aircraft from 13 - 26 September, 1995. For the selected earth surface from the airborne lidar data, an average beta for the surface was established and the statistics of lidar efficiency was determined. This was compared with the actual lidar efficiency

  15. A Compact Laboratory Spectro-Goniometer (CLabSpeG) to Assess the BRDF of Materials. Presentation, Calibration and Implementation on Fagus sylvatica L. Leaves

    PubMed Central

    Biliouris, Dimitrios; Verstraeten, Willem W.; Dutré, Phillip; van Aardt, Jan A.N.; Muys, Bart; Coppin, Pol

    2007-01-01

    The design and calibration of a new hyperspectral Compact Laboratory Spectro-Goniometer (CLabSpeG) is presented. CLabSpeG effectively measures the bidirectional reflectance Factor (BRF) of a sample, using a halogen light source and an Analytical Spectral Devices (ASD) spectroradiometer. The apparatus collects 4356 reflectance data readings covering the spectrum from 350 nm to 2500 nm by independent positioning of the sensor, sample holder, and light source. It has an azimuth and zenith resolution of 30 and 15 degrees, respectively. CLabSpeG is used to collect BRF data and extract Bidirectional Reflectance Distribution Function (BRDF) data of non-isotropic vegetation elements such as bark, soil, and leaves. Accurate calibration has ensured robust geometric accuracy of the apparatus, correction for the conicality of the light source, while sufficient radiometric stability and repeatability between measurements are obtained. The bidirectional reflectance data collection is automated and remotely controlled and takes approximately two and half hours for a BRF measurement cycle over a full hemisphere with 125 cm radius and 2.4 minutes for a single BRF acquisition. A specific protocol for vegetative leaf collection and measurement was established in order to investigate the possibility to extract BRDF values from Fagus sylvatica L. leaves under laboratory conditions. Drying leaf effects induce a reflectance change during the BRF measurements due to the laboratory illumination source. Therefore, the full hemisphere could not be covered with one leaf. Instead 12 BRF measurements per leaf were acquired covering all azimuth positions for a single light source zenith position. Data are collected in radiance format and reflectance is calculated by dividing the leaf cycle measurement with a radiance cycle of a Spectralon reference panel, multiplied by a Spectralon reflectance correction factor and a factor to correct for the conical effect of the light source. BRF results of

  16. The Use of Transfer Radiometers in Validating the Visible through Shortwave Infrared Calibrations of Radiance Sources Used by Instruments in NASA's Earth Observing System

    NASA Technical Reports Server (NTRS)

    Butler, James J.; Barnes, Robert A.

    2002-01-01

    The detection and study of climate change over a time frame of decades requires successive generations of satellite, airborne, and ground-based instrumentation carefully calibrated against a common radiance scale. In NASA s Earth Observing System (EOS) program, the pre-launch radiometric calibration of these instruments in the wavelength region from 400 nm to 2500 nm is accomplished using internally illuminated integrating spheres and diffuse reflectance panels illuminated by irradiance standard lamps. Since 1995, the EOS Calibration Program operating within the EOS Project Science Office (PSO) has enlisted the expertise of national standards laboratories and government and university metrology laboratories in an effort to validate the radiance scales assigned to sphere and panel radiance sources by EOS instrument calibration facilities. This state-of-the-art program has been accomplished using ultra-stable transfer radiometers independently calibrated by the above participating institutions. In ten comparisons since February 1995, the agreement between the radiance measurements of the transfer radiometers is plus or minus 1.80% at 411 nm, plus or minus 1.31% at 552.5 nm, plus or minus 1.32% at 868.0 nm, plus or minus 2.54% at 1622nm, and plus or minus 2.81% at 2200nm (sigma =1).

  17. Application of advanced shearing techniques to the calibration of autocollimators with small angle generators and investigation of error sources.

    PubMed

    Yandayan, T; Geckeler, R D; Aksulu, M; Akgoz, S A; Ozgur, B

    2016-05-01

    The application of advanced error-separating shearing techniques to the precise calibration of autocollimators with Small Angle Generators (SAGs) was carried out for the first time. The experimental realization was achieved using the High Precision Small Angle Generator (HPSAG) of TUBITAK UME under classical dimensional metrology laboratory environmental conditions. The standard uncertainty value of 5 mas (24.2 nrad) reached by classical calibration method was improved to the level of 1.38 mas (6.7 nrad). Shearing techniques, which offer a unique opportunity to separate the errors of devices without recourse to any external standard, were first adapted by Physikalisch-Technische Bundesanstalt (PTB) to the calibration of autocollimators with angle encoders. It has been demonstrated experimentally in a clean room environment using the primary angle standard of PTB (WMT 220). The application of the technique to a different type of angle measurement system extends the range of the shearing technique further and reveals other advantages. For example, the angular scales of the SAGs are based on linear measurement systems (e.g., capacitive nanosensors for the HPSAG). Therefore, SAGs show different systematic errors when compared to angle encoders. In addition to the error-separation of HPSAG and the autocollimator, detailed investigations on error sources were carried out. Apart from determination of the systematic errors of the capacitive sensor used in the HPSAG, it was also demonstrated that the shearing method enables the unique opportunity to characterize other error sources such as errors due to temperature drift in long term measurements. This proves that the shearing technique is a very powerful method for investigating angle measuring systems, for their improvement, and for specifying precautions to be taken during the measurements.

  18. Clarity: an open-source manager for laboratory automation.

    PubMed

    Delaney, Nigel F; Rojas Echenique, José I; Marx, Christopher J

    2013-04-01

    Software to manage automated laboratories, when interfaced with hardware instruments, gives users a way to specify experimental protocols and schedule activities to avoid hardware conflicts. In addition to these basics, modern laboratories need software that can run multiple different protocols in parallel and that can be easily extended to interface with a constantly growing diversity of techniques and instruments. We present Clarity, a laboratory automation manager that is hardware agnostic, portable, extensible, and open source. Clarity provides critical features including remote monitoring, robust error reporting by phone or email, and full state recovery in the event of a system crash. We discuss the basic organization of Clarity, demonstrate an example of its implementation for the automated analysis of bacterial growth, and describe how the program can be extended to manage new hardware. Clarity is mature, well documented, actively developed, written in C# for the Common Language Infrastructure, and is free and open-source software. These advantages set Clarity apart from currently available laboratory automation programs. The source code and documentation for Clarity is available at http://code.google.com/p/osla/.

  19. Radiometric calibration of a 100 cm sphere integrating source for VIIRS solar diffuser stability monitor bands

    NASA Astrophysics Data System (ADS)

    Kim, Eugene D.; Murgai, Vijay; Menzel, Reinhard W.

    2012-09-01

    The Visible Infrared Imaging Radiometer Suite (VIIRS) sensor on the Joint Polar-orbiting Satellite System (JPSS) mission has a solar diffuser as a reflective band calibrator. Due to UV solarization of the solar diffuser, the Solar Diffuser Stability Monitor (SDSM) is on-board to track the reflectance change of the solar diffuser in visible to near IR wavelengths. A 100 cm Sphere Integrating Source (SIS) has been used to configure and test the SDSM on the ground since MODerate resolution Imaging Spectroradiometer (MODIS) programs. Recent upgrades of the radiance transfer and BRDF measurement instruments in Raytheon have enabled more spectral data and faster measurement time with comparable uncertainty to the previous methods. The SIS has a Radiance Monitor, which has been mainly used as a SIS real-time health checker. It has been observed that the Radiance Monitor response is sufficiently linear and stable thus the Radiance Monitor can be used as a calibrator for ground tests. This paper describes the upgraded SIS calibration instruments, and the changes in the calibration philosophy of the SIS for the SDSM bands.

  20. A 220Rn source for the calibration of low-background experiments

    NASA Astrophysics Data System (ADS)

    Lang, R. F.; Brown, A.; Brown, E.; Cervantes, M.; Macmullin, S.; Masson, D.; Schreiner, J.; Simgen, H.

    2016-04-01

    We characterize two 40 kBq sources of electrodeposited 228Th for use in low-background experiments. The sources efficiently emanate 220Rn, a noble gas that can diffuse in a detector volume. 220Rn and its daughter isotopes produce α-, β-, and γ-radiation, which may used to calibrate a variety of detector responses and features, before decaying completely in only a few days. We perform various tests to place limits on the release of other long-lived isotopes. In particular, we find an emanation of < 0.008 atoms/min/kBq (90% CL) for 228Th and (1.53 ± 0.04) atoms/min/kBq for 224Ra. The sources lend themselves in particular to the calibration of detectors employing liquid noble elements such as argon and xenon. With the source mounted in a noble gas system, we demonstrate that filters are highly efficient in reducing the activity of these longer-lived isotopes further. We thus confirm the suitability of these sources even for use in next-generation experiments, such as XENON1T/XENONnT, LZ, and nEXO.

  1. Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion source.

    PubMed

    Kondo, K; Yamamoto, T; Sekine, M; Okamura, M

    2012-02-01

    The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current (∼100 μA) with high charge (∼10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline.

  2. Development of hollow anode penning ion source for laboratory application

    NASA Astrophysics Data System (ADS)

    Das, B. K.; Shyam, A.; Das, R.; Rao, A. D. P.

    2012-03-01

    The research work presented here focuses for the development of miniature penning type ion source. One hollow anode penning type ion source was developed in our laboratory. The size of the ion source is 38 mm diameter and 55 mm length. The ion source consists of two cathodes, a hollow anode and one piece of rare earth permanent magnet. The plasma was created in the plasma region between cathodes and the hollow anode. The J × B force in the region helps for efficient ionization of the gas even in the high vacuum region˜1×10 -5 Torr. The ions were extracted in the axial direction with help of the potential difference between the electrodes and the geometry of the extraction angle. The effect of the extraction electrode geometry for efficient extraction of the ions from the plasma region was examined. This ion source is a self extracted ion source. The self extracted phenomena reduce the cost and the size of the ion source. The extracted ion current was measured by a graphite probe. An ion current of more than 200 μA was observed at the probe placed 70 mm apart from the extraction electrode. In this paper, the structure of the ion source, effect of operating pressure, potential difference and the magnetic field on the extracted ion current is reported.

  3. Compact extreme ultraviolet source for laboratory-based photoemission spectromicroscopy

    NASA Astrophysics Data System (ADS)

    Schmitz, Christoph; Wilson, Daniel; Rudolf, Denis; Wiemann, Carsten; Plucinski, Lukasz; Riess, Sally; Schuck, Martin; Hardtdegen, Hilde; Schneider, Claus M.; Tautz, F. Stefan; Juschkin, Larissa

    2016-06-01

    We report on the combination of a state-of-the-art energy-filtering photoemission electron microscope with an intense yet compact laboratory-based gas discharge extreme ultraviolet (EUV) light source. Using a photon energy of 71.7 eV from oxygen plasma (O5+ spectral line), we demonstrate element-selective photoelectron imaging in real space and band structure mapping in reciprocal space. Additionally, the high surface sensitivity of the EUV light was used to study the surface oxidation on islands of the phase-change material Ge1Sb2Te4 . The EUV light source allows the extension of spectromicroscopy, previously only feasible at synchrotron beamlines, to laboratory-based work.

  4. Single-source gamma radiation procedures for improved calibration and measurements in porous media

    SciTech Connect

    Oostrom, M.; Hofstee, C.; Dane, H.; Lenhard, R.J.

    1998-08-01

    When dual-energy gamma radiation systems are employed for measurements in porous media, count rates from both sources are often used to compute parameter values. However, for several applications, the count rates of just one source are insufficient. These applications include the determination of volumetric liquid content values in two-liquid systems and salt concentration values in water-saturated porous media. Single-energy gamma radiation procedures for three applications are described in this paper. Through an error analysis, single-source procedures are shown to reduce the probable error in the determinations considerably. Example calculations and simple column experiments were conducted for each application to compare the performance of the new single-source and standard dual-source methods. In all cases, the single-source methods provided more reliable data than the traditional dual-source methods. In addition, a single-source calibration procedure is proposed to determine incident count rates indirectly. This procedure, which requires packing under saturated conditions, can be used in all single- and dual-source applications and yields accurate porosity and dry bulk density values.

  5. Laboratory Calibration of Density-Dependent Lines in the EUV and Soft X-Ray Regions

    SciTech Connect

    Lepson, J K; Beiersdorfer, P; Gu, M F; Desai, P

    2010-12-09

    We analyzed spectral data of Fe XXII and Ar XIV from laboratory sources in which the electron density varies by several orders of magnitude to help benchmark density-sensitive emission lines useful for astrophysics and to test the atomic models underlying the diagnostic line ratios. We found excellent agreement for Fe XXII, but poorer agreement for Ar XIV. A number of astrophysically important emission lines are sensitive to electron density in the EUV and soft X-ray regions. Lines from Fe XXII, for example, have been used in recent years as diagnostics of stellar coronae, such as the active variable AB Dor, Capella, and EX Hya (Sanz-Forcada et al. 2003, Mewe et al. 2001, Mauche et al. 2003). Here we report spectral data of Fe XXII and Ar XIV from laboratory sources in which the electron density is known from either K-shell density diagnostics (for electron beam ion traps) or from non-spectroscopic means (tokamaks), ranging from 5 x 10{sup 10} cm{sup -3} to 5 x 10{sup 14} cm{sup -3}. These measurements were used to test the atomic data underlying the density diagnostic line ratios, complementing earlier work (Chen et al. 2004).

  6. A method to calibrate phase fluctuation in polarization-sensitive swept-source optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Lu, Zenghai; Kasaragod, Deepa K.; Matcher, Stephen J.

    2011-06-01

    A phase fluctuation calibration method is presented for polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) using continuous polarization modulation. The method consists of the generation of a continuous triggered tone-burst waveform rather than an asynchronous waveform by use of a function generator and the removal of the global phases of the measured Jones matrices by use of matrix normalization. This could remove the use of auxiliary optical components for the phase fluctuation compensation in the system, which reduces the system complexity. Phase fluctuation calibration is necessary to obtain the reference Jones matrix by averaging the measured Jones matrices at sample surfaces. Measurements on an equine tendon sample were made by the PS-SS-OCT system to validate the proposed method.

  7. Flux-Calibrated Emission-Line Imaging of Extended Sources Using GTC/OSIRIS Tunable Filters

    NASA Astrophysics Data System (ADS)

    Mayya, Y. D.; Rosa González, D.; Vega, O.; Méndez-Abreu, J.; Terlevich, R.; Terlevich, E.; Bertone, E.; Rodríguez-Merino, L. H.; Muñoz-Tuñón, C.; Rodríguez-Espinosa, J. M.; Sánchez Almeida, J.; Aguerri, J. A. L.

    2012-08-01

    We investigate the utility of the tunable filters (TFs) for obtaining flux-calibrated emission-line maps of extended objects such as galactic nebulae and nearby galaxies using the Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) at the 10.4-m Gran Telescopio Canarias (GTC). Despite the relatively large field of view (FoV) of OSIRIS (8' × 8'), the change in wavelength across the field (~80 Å) and the long tail of the TF spectral response function are hindrances for obtaining accurate flux-calibrated emission-line maps of extended sources. The purpose of this article is to demonstrate that emission-line maps useful for diagnostics of nebulae can be generated over the entire FoV of OSIRIS if we make use of theoretically well-understood characteristics of TFs. We have successfully generated the flux-calibrated images of the nearby large late-type spiral galaxy M101 in the emission lines of Hα, [N II]λ6583, [S II]λ6716 and [S II]λ6731. We find that the present uncertainty in setting the central wavelength of TFs (~1 Å) is the biggest source of error in the emission-line fluxes. By comparing the Hα fluxes of H II regions in our images with the fluxes derived from Hα images obtained using narrow-band filters, we estimate an error of ~11% in our fluxes. The flux-calibration of the images was carried out by fitting the Sloan Digital Sky Survey (SDSS) griz magnitudes of in-frame stars with the stellar spectra from the SDSS spectral database. This method resulted in an accuracy of 3% in flux-calibration of any narrow-band image, which is as good as, if not better than, what has been feasible using the observations of spectrophotometric standard stars. Thus time-consuming calibration images need not be taken. A user-friendly script under the IRAF environment was developed and is available on request. Based on observations made with the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the

  8. Radiometric Measurement Comparison on the Integrating Sphere Source Used to Calibrate the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Landsat 7 Enhanced Thematic Mapper Plus (ETM+).

    PubMed

    Butler, James J; Brown, Steven W; Saunders, Robert D; Johnson, B Carol; Biggar, Stuart F; Zalewski, Edward F; Markham, Brian L; Gracey, Paul N; Young, James B; Barnes, Robert A

    2003-01-01

    As part of a continuing effort to validate the radiometric scales assigned to integrating sphere sources used in the calibration of Earth Observing System (EOS) instruments, a radiometric measurement comparison was held in May 1998 at Raytheon/Santa Barbara Remote Sensing (SBRS). This comparison was conducted in support of the calibration of the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) instruments. The radiometric scale assigned to the Spherical Integrating Source (SIS100) by SBRS was validated through a comparison with radiometric measurements made by a number of stable, well-characterized transfer radiometers from the National Institute of Standards and Technology (NIST), the National Aeronautics and Space Administration's Goddard Space Flight Center (NASA's GSFC), and the University of Arizona Optical Sciences Center (UA). The measured radiances from the radiometers differed by ±3 % in the visible to near infrared when compared to the SBRS calibration of the sphere, and the overall agreement was within the combined uncertainties of the individual measurements. In general, the transfer radiometers gave higher values than the SBRS calibration in the near infrared and lower values in the blue. The measurements of the radiometers differed by ±4 % from 800 nm to 1800 nm compared to the SBRS calibration of the sphere, and the overall agreement was within the combined uncertainties of the individual measurements for wavelengths less than 2200 nm. The results of the radiometric measurement comparison presented here supplement the results of previous measurement comparisons on the integrating sphere sources used to calibrate the Multi-angle Imaging SpectroRadiometer (MISR) at NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) at NEC Corporation, Yokohama, Japan. PMID:27413606

  9. Radiometric Measurement Comparison on the Integrating Sphere Source Used to Calibrate the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Landsat 7 Enhanced Thematic Mapper Plus (ETM+).

    PubMed

    Butler, James J; Brown, Steven W; Saunders, Robert D; Johnson, B Carol; Biggar, Stuart F; Zalewski, Edward F; Markham, Brian L; Gracey, Paul N; Young, James B; Barnes, Robert A

    2003-01-01

    As part of a continuing effort to validate the radiometric scales assigned to integrating sphere sources used in the calibration of Earth Observing System (EOS) instruments, a radiometric measurement comparison was held in May 1998 at Raytheon/Santa Barbara Remote Sensing (SBRS). This comparison was conducted in support of the calibration of the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) instruments. The radiometric scale assigned to the Spherical Integrating Source (SIS100) by SBRS was validated through a comparison with radiometric measurements made by a number of stable, well-characterized transfer radiometers from the National Institute of Standards and Technology (NIST), the National Aeronautics and Space Administration's Goddard Space Flight Center (NASA's GSFC), and the University of Arizona Optical Sciences Center (UA). The measured radiances from the radiometers differed by ±3 % in the visible to near infrared when compared to the SBRS calibration of the sphere, and the overall agreement was within the combined uncertainties of the individual measurements. In general, the transfer radiometers gave higher values than the SBRS calibration in the near infrared and lower values in the blue. The measurements of the radiometers differed by ±4 % from 800 nm to 1800 nm compared to the SBRS calibration of the sphere, and the overall agreement was within the combined uncertainties of the individual measurements for wavelengths less than 2200 nm. The results of the radiometric measurement comparison presented here supplement the results of previous measurement comparisons on the integrating sphere sources used to calibrate the Multi-angle Imaging SpectroRadiometer (MISR) at NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) at NEC Corporation, Yokohama, Japan.

  10. Monte Carlo based calibration of scintillation detectors for laboratory and in situ gamma ray measurements.

    PubMed

    van der Graaf, E R; Limburg, J; Koomans, R L; Tijs, M

    2011-03-01

    The calibration of scintillation detectors for gamma radiation in a well characterized setup can be transferred to other geometries using Monte Carlo simulations to account for the differences between the calibration and the other geometry. In this study a calibration facility was used that is constructed from bricks of well-known activity concentrations of ⁴⁰K and of radionuclides from the ²³⁸U- and ²³²Th-series. Transfer of the calibration was attempted to a Marinelli beaker geometry with the detector inside a lead shield and to an in situ application with the detector positioned on a sand bed. In general this resulted in good correspondence (within 5-10%) between the activity concentrations derived using the transferred calibration and activities that were derived by independent measurements. Some discrepancies were identified that were attributed to coincident summing in the natural decay series and interference of radon. PMID:21251733

  11. Laboratory calibration of the calcium carbonate clumped isotope thermometer in the 25-250 °C temperature range

    NASA Astrophysics Data System (ADS)

    Kluge, Tobias; John, Cédric M.; Jourdan, Anne-Lise; Davis, Simon; Crawshaw, John

    2015-05-01

    Many fields of Earth sciences benefit from the knowledge of mineral formation temperatures. For example, carbonates are extensively used for reconstruction of the Earth's past climatic variations by determining ocean, lake, and soil paleotemperatures. Furthermore, diagenetic minerals and their formation or alteration temperature may provide information about the burial history of important geological units and can have practical applications, for instance, for reconstructing the geochemical and thermal histories of hydrocarbon reservoirs. Carbonate clumped isotope thermometry is a relatively new technique that can provide the formation temperature of carbonate minerals without requiring a priori knowledge of the isotopic composition of the initial solution. It is based on the temperature-dependent abundance of the rare 13C-18O bonds in carbonate minerals, specified as a Δ47 value. The clumped isotope thermometer has been calibrated experimentally from 1 °C to 70 °C. However, higher temperatures that are relevant to geological processes have so far not been directly calibrated in the laboratory. In order to close this calibration gap and to provide a robust basis for the application of clumped isotopes to high-temperature geological processes we precipitated CaCO3 (mainly calcite) in the laboratory between 23 and 250 °C. We used two different precipitation techniques: first, minerals were precipitated from a CaCO3 supersaturated solution at atmospheric pressure (23-91 °C), and, second, from a solution resulting from the mixing of CaCl2 and NaHCO3 in a pressurized reaction vessel at a pressure of up to 80 bar (25-250 °C). The calibration lines of both experimental approaches overlap and agree in the slopes with theoretical estimates and with other calibration experiments in which carbonates were reacted with phosphoric acid at temperatures above 70 °C. Our study suggests a universal Δ47-T calibration (T in K, Δ47 in ‰):

  12. Measuring sound absorption properties of porous materials using a calibrated volume velocity source

    NASA Astrophysics Data System (ADS)

    Arenas, Jorge P.; Darmendrail, Luis

    2013-10-01

    Measurement of acoustic properties of sound-absorbing materials has been the source of much investigation that has produced practical measuring methods. In particular, the measurement of the normal incidence sound absorption coefficient is commonly done using a well-known configuration of a tube carrying a plane wave. The sound-absorbing coefficient is calculated from the surface impedance measured on a sample of material. Therefore, a direct measurement of the impedance requires knowing the ratio between the sound pressure and the volume velocity. However, the measurement of volume velocity is not straightforward in practice and many methods have been proposed including complex transducers, laser vibrometry, accelerometers and calibrated volume velocity sources. In this paper, a device to directly measure the acoustic impedance of a sample of sound-absorbing material is presented. The device uses an internal microphone in a small cavity sealed by a loudspeaker and a second microphone mounted in front of this source. The calibration process of the device and the limitations of the method are also discussed and measurement examples are presented. The accuracy of the device was assessed by direct comparison with the standardized method. The proposed measurement method was tested successfully with various types of commercial acoustic porous materials.

  13. Evaluation of the Earth Radiation Budget Experiment (ERBE) shortwave channel's stability using in-flight calibration sources

    NASA Technical Reports Server (NTRS)

    Gibson, Michael A.; Lee, Robert B., III; Thomas, Susan

    1992-01-01

    The Earth Radiation Budget Experiment (ERBE) radiometers were designed to make absolute measurements of the incoming solar, earth-reflected solar, and earth-emitted fluxes for investigations of the earth's climate system. Thermistor bolometers were the sensors used for the ERBE scanning radiometric package. Each thermistor bolometer package consisted of three narrow field of view broadband radiometric channels measuring shortwave, longwave, and total (0.2 micron to 50 microns) radiation. The in-flight calibration facilities include Mirror Attenuator Mosaics, shortwave internal calibration source, and internal blackbody sources to monitor the long-term responsivity of the radiometers. This paper describes the in-flight calibration facilities, the calibration data reduction techniques, and the results from the in-flight shortwave channel calibrations. The results indicate that the ERBE shortwave detectors were stable to within +/- 1 percent for up to five years of flight operation.

  14. The moon as a radiometric reference source for on-orbit sensor stability calibration

    USGS Publications Warehouse

    Stone, T.C.

    2009-01-01

    The wealth of data generated by the world's Earth-observing satellites, now spanning decades, allows the construction of long-term climate records. A key consideration for detecting climate trends is precise quantification of temporal changes in sensor calibration on-orbit. For radiometer instruments in the solar reflectance wavelength range (near-UV to shortwave-IR), the Moon can be viewed as a solar diffuser with exceptional stability properties. A model for the lunar spectral irradiance that predicts the geometric variations in the Moon's brightness with ???1% precision has been developed at the U.S. Geological Survey in Flagstaff, AZ. Lunar model results corresponding to a series of Moon observations taken by an instrument can be used to stabilize sensor calibration with sub-percent per year precision, as demonstrated by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). The inherent stability of the Moon and the operational model to utilize the lunar irradiance quantity provide the Moon as a reference source for monitoring radiometric calibration in orbit. This represents an important capability for detecting terrestrial climate change from space-based radiometric measurements.

  15. Rapid calibrated high-resolution hyperspectral imaging using tunable laser source

    NASA Astrophysics Data System (ADS)

    Nguyen, Lam K.; Margalith, Eli

    2009-05-01

    We present a novel hyperspectral imaging technique based on tunable laser technology. By replacing the broadband source and tunable filters of a typical NIR imaging instrument, several advantages are realized, including: high spectral resolution, highly variable field-of-views, fast scan-rates, high signal-to-noise ratio, and the ability to use optical fiber for efficient and flexible sample illumination. With this technique, high-resolution, calibrated hyperspectral images over the NIR range can be acquired in seconds. The performance of system features will be demonstrated on two example applications: detecting melamine contamination in wheat gluten and separating bovine protein from wheat protein in cattle feed.

  16. Calibration of the Regional Crustal Waveguide and the Retrieval of Source Parameters Using Waveform Modeling

    NASA Astrophysics Data System (ADS)

    Saikia, C. K.; Woods, B. B.; Thio, H. K.

    - Regional crustal waveguide calibration is essential to the retrieval of source parameters and the location of smaller (M<4.8) seismic events. This path calibration of regional seismic phases is strongly dependent on the accuracy of hypocentral locations of calibration (or master) events. This information can be difficult to obtain, especially for smaller events. Generally, explosion or quarry blast generated travel-time data with known locations and origin times are useful for developing the path calibration parameters, but in many regions such data sets are scanty or do not exist. We present a method which is useful for regional path calibration independent of such data, i.e. with earthquakes, which is applicable for events down to Mw = 4 and which has successfully been applied in India, central Asia, western Mediterranean, North Africa, Tibet and the former Soviet Union. These studies suggest that reliably determining depth is essential to establishing accurate epicentral location and origin time for events. We find that the error in source depth does not necessarily trade-off only with the origin time for events with poor azimuthal coverage, but with the horizontal location as well, thus resulting in poor epicentral locations. For example, hypocenters for some events in central Asia were found to move from their fixed-depth locations by about 20km. Such errors in location and depth will propagate into path calibration parameters, particularly with respect to travel times. The modeling of teleseismic depth phases (pP, sP) yields accurate depths for earthquakes down to magnitude Mw = 4.7. This Mwthreshold can be lowered to four if regional seismograms are used in conjunction with a calibrated velocity structure model to determine depth, with the relative amplitude of the Pnl waves to the surface waves and the interaction of regional sPmP and pPmP phases being good indicators of event depths. We also found that for deep events a seismic phase which follows an S

  17. Laboratory calibration of density-dependent lines in the extreme ultraviolet spectral region

    SciTech Connect

    Lepson, J. K.; Beiersdorfer, P.; Gu, M. F.; Desai, P.; Bitter, M.; Roquemore, L.; Reinke, M. L.

    2012-05-25

    We have been making spectral measurements in the extreme ultraviolet (EUV) from different laboratory sources in order to investigate the electron density dependence of various astrophysically important emission lines and to test the atomic models underlying the diagnostic line ratios. The measurement are being performed at the Livermore EBIT-I electron beam ion trap, the National Spherical Torus Experiment (NSTX) at Princeton, and the Alcator C-Mod tokamak at the Massachusetts Institute of Technology, which together span an electron density of four orders of magnitude and which allow us to test the various models at high and low density limits. Here we present measurements of Fe XXII and Ar XIV, which include new data from an ultra high resolution ({lambda}/{Delta}{lambda} >4000) spectrometer at the EBIT-I facility. We found good agreement between the measurements and modeling calculations for Fe XXII, but poorer agreement for Ar XIV.

  18. Calibration and Laboratory Test of the Department of Energy Cloud Particle Imager

    SciTech Connect

    McFarquhar, GM; Um, J

    2012-02-17

    Calibration parameters from the Connolly et al. (2007) algorithm cannot be applied to the Department of Energy's (DOE) CPI because the DOE CPI is version 2.0. Thus, Dr. Junshik Um and Prof. Greg McFarquhar brought the DOE CPI to the University of Manchester, UK, where facilities for calibrating it were available. In addition, two other versions of CPIs (1.0 and 1.5) were available on-site at the University of Manchester so that an intercomparison of three different versions of the CPI was possible. The three CPIs (versions 1.0, 1.5, and 2.0) were calibrated by moving glass calibration beads and ice analogues of known size parallel to the object plane. The distance between the object plane and a particle, the particle's focus, its apparent maximum dimension, and a background image were measured in order to derive calibration parameters for each CPI version. The calibration parameters are used in two empirical equations that are applied to in situ CPI data to determine particle size and depth of field, and hence particle size distributions (PSDs). After the tests with the glass calibration beads to derive the calibration parameters, the three CPIs were installed at the base of the Manchester Ice Cloud Chamber and connected to air pumps that drew cloud through the sample volume. Warm liquid clouds at a temperature of 1-2 C and ice clouds at a temperature of -5 C were generated, and the resulting PSDs for each of the CPIs were determined by applying the results of each calibration.

  19. Laboratory soft x-ray source with foil target

    NASA Astrophysics Data System (ADS)

    Stephan, Karl-Heinz; Braeuninger, Heinrich W.

    1993-02-01

    We have developed a comparatively small soft x-ray source for application in our test facilities, which are used at present to support the developments of the astrophysical space projects XMM and AXAF. The instrument comprises a commercially available color television tube for generation of the electron beam, which is focused on exchangeable metal films serving as targets. The x rays are taken off after having transversed the foil target and have a sufficient spectral purity with regard to the experimental requirements. The maximum electric operating parameters correspond to an emission current of 100 (mu) A generated by a filament heating power of 6.6 watt at an accelerating voltage of 25 kV. The technical advantages of the instrument are lightweight construction, no water cooling, small size electric supply, cost efficient manufacturing, small sized focus, and quick access to the desired characteristic spectral line by exchange of a complete tube. We describe the measurements on the local x-ray intensity profile of the focus, the spectral features of the beam, and present the resulting performance data. A special development could be used as calibration sources in x-ray telescopes.

  20. Radio Frequency Plasma Discharge Lamps for Use as Stable Calibration Light Sources

    NASA Technical Reports Server (NTRS)

    McAndrew, Brendan; Cooper, John; Arecchi, Angelo; McKee, Greg; Durell, Christopher

    2012-01-01

    Stable high radiance in visible and near-ultraviolet wavelengths is desirable for radiometric calibration sources. In this work, newly available electrodeless radio-frequency (RF) driven plasma light sources were combined with research grade, low-noise power supplies and coupled to an integrating sphere to produce a uniform radiance source. The stock light sources consist of a 28 VDC power supply, RF driver, and a resonant RF cavity. The RF cavity includes a small bulb with a fill gas that is ionized by the electric field and emits light. This assembly is known as the emitter. The RF driver supplies a source of RF energy to the emitter. In commercial form, embedded electronics within the RF driver perform a continual optimization routine to maximize energy transfer to the emitter. This optimization routine continually varies the light output sinusoidally by approximately 2% over a several-second period. Modifying to eliminate this optimization eliminates the sinusoidal variation but allows the output to slowly drift over time. This drift can be minimized by allowing sufficient warm-up time to achieve thermal equilibrium. It was also found that supplying the RF driver with a low-noise source of DC electrical power improves the stability of the lamp output. Finally, coupling the light into an integrating sphere reduces the effect of spatial fluctuations, and decreases noise at the output port of the sphere.

  1. Innovative methodology for intercomparison of radionuclide calibrators using short half-life in situ prepared radioactive sources

    SciTech Connect

    Oliveira, P. A.; Santos, J. A. M.

    2014-07-15

    Purpose: An original radionuclide calibrator method for activity determination is presented. The method could be used for intercomparison surveys for short half-life radioactive sources used in Nuclear Medicine, such as{sup 99m}Tc or most positron emission tomography radiopharmaceuticals. Methods: By evaluation of the resulting net optical density (netOD) using a standardized scanning method of irradiated Gafchromic XRQA2 film, a comparison of the netOD measurement with a previously determined calibration curve can be made and the difference between the tested radionuclide calibrator and a radionuclide calibrator used as reference device can be calculated. To estimate the total expected measurement uncertainties, a careful analysis of the methodology, for the case of{sup 99m}Tc, was performed: reproducibility determination, scanning conditions, and possible fadeout effects. Since every factor of the activity measurement procedure can influence the final result, the method also evaluates correct syringe positioning inside the radionuclide calibrator. Results: As an alternative to using a calibrated source sent to the surveyed site, which requires a relatively long half-life of the nuclide, or sending a portable calibrated radionuclide calibrator, the proposed method uses a source preparedin situ. An indirect activity determination is achieved by the irradiation of a radiochromic film using {sup 99m}Tc under strictly controlled conditions, and cumulated activity calculation from the initial activity and total irradiation time. The irradiated Gafchromic film and the irradiator, without the source, can then be sent to a National Metrology Institute for evaluation of the results. Conclusions: The methodology described in this paper showed to have a good potential for accurate (3%) radionuclide calibrators intercomparison studies for{sup 99m}Tc between Nuclear Medicine centers without source transfer and can easily be adapted to other short half-life radionuclides.

  2. Calibration of Seismic Sources during a Test Cruise with the new RV SONNE

    NASA Astrophysics Data System (ADS)

    Engels, M.; Schnabel, M.; Damm, V.

    2015-12-01

    During autumn 2014, several test cruises of the brand new German research vessel SONNE were carried out before the first official scientific cruise started in December. In September 2014, BGR conducted a seismic test cruise in the British North Sea. RV SONNE is a multipurpose research vessel and was also designed for the mobile BGR 3D seismic equipment, which was tested successfully during the cruise. We spend two days for calibration of the following seismic sources of BGR: G-gun array (50 l @ 150 bar) G-gun array (50 l @ 207 bar) single GI-gun (3.4 l @ 150 bar) For this experiment two hydrophones (TC4042 from Reson Teledyne) sampling up to 48 kHz were fixed below a drifting buoy at 20 m and 60 m water depth - the sea bottom was at 80 m depth. The vessel with the seismic sources sailed several up to 7 km long profiles around the buoy in order to cover many different azimuths and distances. We aimed to measure sound pressure level (SPL) and sound exposure level (SEL) under the conditions of the shallow North Sea. Total reflections and refracted waves dominate the recorded wave field, enhance the noise level and partly screen the direct wave in contrast to 'true' deep water calibration based solely on the direct wave. Presented are SPL and RMS power results in time domain, the decay with distance along profiles, and the somehow complicated 2D sound radiation pattern modulated by topography. The shading effect of the vessel's hull is significant. In frequency domain we consider 1/3 octave levels and estimate the amount of energy in frequency ranges not used for reflection seismic processing. Results are presented in comparison of the three different sources listed above. We compare the measured SPL decay with distance during this experiment with deep water modeling of seismic sources (Gundalf software) and with published results from calibrations with other marine seismic sources under different conditions: E.g. Breitzke et al. (2008, 2010) with RV Polarstern

  3. Data-driven and calibration-free Lamb wave source localization with sparse sensor arrays.

    PubMed

    Harley, Joel B; Moura, José M F

    2015-08-01

    Most Lamb wave localization techniques require that we know the wave's velocity characteristics; yet, in many practical scenarios, velocity estimates can be challenging to acquire, are unavailable, or are unreliable because of the complexity of Lamb waves. As a result, there is a significant need for new methods that can reduce a system's reliance on a priori velocity information. This paper addresses this challenge through two novel source localization methods designed for sparse sensor arrays in isotropic media. Both methods exploit the fundamental sparse structure of a Lamb wave's frequency-wavenumber representation. The first method uses sparse recovery techniques to extract velocities from calibration data. The second method uses kurtosis and the support earth mover's distance to measure the sparseness of a Lamb wave's approximate frequency-wavenumber representation. These measures are then used to locate acoustic sources with no prior calibration data. We experimentally study each method with a collection of acoustic emission data measured from a 1.22 m by 1.22 m isotropic aluminum plate. We show that both methods can achieve less than 1 cm localization error and have less systematic error than traditional time-of-arrival localization methods. PMID:26276960

  4. The Idaho National Engineering and Environmental Laboratory Source Water Assessment

    SciTech Connect

    Sehlke, G.

    2003-03-17

    The Idaho National Engineering and Environmental Laboratory (INEEL) covers approximately 890 square miles and includes 12 public water systems that must be evaluated for Source water protection purposes under the Safe Drinking Water Act. Because of its size and location, six watersheds and five aquifers could potentially affect the INEEL's drinking water sources. Based on a preliminary evaluation of the available information, it was determined that the Big Lost River, Birch Creek, and Little Lost River Watersheds and the eastern Snake River Plain Aquifer needed to be assessed. These watersheds were delineated using the United States Geologic Survey's Hydrological Unit scheme. Well capture zones were originally estimated using the RESSQC module of the Environmental Protection Agency's Well Head Protection Area model, and the initial modeling assumptions and results were checked by running several scenarios using Modflow modeling. After a technical review, the resulting capture zones were expanded to account for the uncertainties associated with changing groundwater flow directions, a this vadose zone, and other data uncertainties. Finally, all well capture zones at a given facility were merged to a single wellhead protection area at each facility. A contaminant source inventory was conducted, and the results were integrated with the well capture zones, watershed and aquifer information, and facility information using geographic information system technology to complete the INEEL's Source Water Assessment. Of the INEEL's 12 public water systems, three systems rated as low susceptibility (EBR-1, Main Gate, and Gun Range), and the remainder rated as moderate susceptibility. No INEEL public water system rated as high susceptibility. We are using this information to develop a source water management plan from which we will subsequently implement an INEEL-wide source water management program. The results are a very robust set of wellhead protection areas that will protect

  5. SEVEN-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP ) OBSERVATIONS: PLANETS AND CELESTIAL CALIBRATION SOURCES

    SciTech Connect

    Weiland, J. L.; Odegard, N.; Hill, R. S.; Greason, M. R.; Wollack, E.; Hinshaw, G.; Kogut, A.; Bennett, C. L.; Gold, B.; Larson, D.; Dunkley, J.; Halpern, M.; Komatsu, E.; Limon, M.; Meyer, S. S.; Nolta, M. R.; Smith, K. M.; Spergel, D. N.

    2011-02-01

    We present WMAP seven-year observations of bright sources which are often used as calibrators at microwave frequencies. Ten objects are studied in five frequency bands (23-94 GHz): the outer planets (Mars, Jupiter, Saturn, Uranus, and Neptune) and five fixed celestial sources (Cas A, Tau A, Cyg A, 3C274, and 3C58). The seven-year analysis of Jupiter provides temperatures which are within 1{sigma} of the previously published WMAP five-year values, with slightly tighter constraints on variability with orbital phase (0.2% {+-} 0.4%), and limits (but no detections) on linear polarization. Observed temperatures for both Mars and Saturn vary significantly with viewing geometry. Scaling factors are provided which, when multiplied by the Wright Mars thermal model predictions at 350 {mu}m, reproduce WMAP seasonally averaged observations of Mars within {approx}2%. An empirical model is described which fits brightness variations of Saturn due to geometrical effects and can be used to predict the WMAP observations to within 3%. Seven-year mean temperatures for Uranus and Neptune are also tabulated. Uncertainties in Uranus temperatures are 3%-4% in the 41, 61, and 94 GHz bands; the smallest uncertainty for Neptune is 8% for the 94 GHz band. Intriguingly, the spectrum of Uranus appears to show a dip at {approx}30 GHz of unidentified origin, although the feature is not of high statistical significance. Flux densities for the five selected fixed celestial sources are derived from the seven-year WMAP sky maps and are tabulated for Stokes I, Q, and U, along with polarization fraction and position angle. Fractional uncertainties for the Stokes I fluxes are typically 1% to 3%. Source variability over the seven-year baseline is also estimated. Significant secular decrease is seen for Cas A and Tau A: our results are consistent with a frequency-independent decrease of about 0.53% per year for Cas A and 0.22% per year for Tau A. We present WMAP polarization data with uncertainties of a

  6. Seven-year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Planets and Celestial Calibration Sources

    NASA Astrophysics Data System (ADS)

    Weiland, J. L.; Odegard, N.; Hill, R. S.; Wollack, E.; Hinshaw, G.; Greason, M. R.; Jarosik, N.; Page, L.; Bennett, C. L.; Dunkley, J.; Gold, B.; Halpern, M.; Kogut, A.; Komatsu, E.; Larson, D.; Limon, M.; Meyer, S. S.; Nolta, M. R.; Smith, K. M.; Spergel, D. N.; Tucker, G. S.; Wright, E. L.

    2011-02-01

    We present WMAP seven-year observations of bright sources which are often used as calibrators at microwave frequencies. Ten objects are studied in five frequency bands (23-94 GHz): the outer planets (Mars, Jupiter, Saturn, Uranus, and Neptune) and five fixed celestial sources (Cas A, Tau A, Cyg A, 3C274, and 3C58). The seven-year analysis of Jupiter provides temperatures which are within 1σ of the previously published WMAP five-year values, with slightly tighter constraints on variability with orbital phase (0.2% ± 0.4%), and limits (but no detections) on linear polarization. Observed temperatures for both Mars and Saturn vary significantly with viewing geometry. Scaling factors are provided which, when multiplied by the Wright Mars thermal model predictions at 350 μm, reproduce WMAP seasonally averaged observations of Mars within ~2%. An empirical model is described which fits brightness variations of Saturn due to geometrical effects and can be used to predict the WMAP observations to within 3%. Seven-year mean temperatures for Uranus and Neptune are also tabulated. Uncertainties in Uranus temperatures are 3%-4% in the 41, 61, and 94 GHz bands; the smallest uncertainty for Neptune is 8% for the 94 GHz band. Intriguingly, the spectrum of Uranus appears to show a dip at ~30 GHz of unidentified origin, although the feature is not of high statistical significance. Flux densities for the five selected fixed celestial sources are derived from the seven-year WMAP sky maps and are tabulated for Stokes I, Q, and U, along with polarization fraction and position angle. Fractional uncertainties for the Stokes I fluxes are typically 1% to 3%. Source variability over the seven-year baseline is also estimated. Significant secular decrease is seen for Cas A and Tau A: our results are consistent with a frequency-independent decrease of about 0.53% per year for Cas A and 0.22% per year for Tau A. We present WMAP polarization data with uncertainties of a few percent for Tau A

  7. Laboratory Plasma Source as an MHD Model for Astrophysical Jets

    NASA Technical Reports Server (NTRS)

    Mayo, Robert M.

    1997-01-01

    The significance of the work described herein lies in the demonstration of Magnetized Coaxial Plasma Gun (MCG) devices like CPS-1 to produce energetic laboratory magneto-flows with embedded magnetic fields that can be used as a simulation tool to study flow interaction dynamic of jet flows, to demonstrate the magnetic acceleration and collimation of flows with primarily toroidal fields, and study cross field transport in turbulent accreting flows. Since plasma produced in MCG devices have magnetic topology and MHD flow regime similarity to stellar and extragalactic jets, we expect that careful investigation of these flows in the laboratory will reveal fundamental physical mechanisms influencing astrophysical flows. Discussion in the next section (sec.2) focuses on recent results describing collimation, leading flow surface interaction layers, and turbulent accretion. The primary objectives for a new three year effort would involve the development and deployment of novel electrostatic, magnetic, and visible plasma diagnostic techniques to measure plasma and flow parameters of the CPS-1 device in the flow chamber downstream of the plasma source to study, (1) mass ejection, morphology, and collimation and stability of energetic outflows, (2) the effects of external magnetization on collimation and stability, (3) the interaction of such flows with background neutral gas, the generation of visible emission in such interaction, and effect of neutral clouds on jet flow dynamics, and (4) the cross magnetic field transport of turbulent accreting flows. The applicability of existing laboratory plasma facilities to the study of stellar and extragalactic plasma should be exploited to elucidate underlying physical mechanisms that cannot be ascertained though astrophysical observation, and provide baseline to a wide variety of proposed models, MHD and otherwise. The work proposed herin represents a continued effort on a novel approach in relating laboratory experiments to

  8. Performance of thin CaSO4:Dy pellets for calibration of a Sr90+Y90 source

    NASA Astrophysics Data System (ADS)

    Oliveira, M. L.; Caldas, L. V. E.

    2007-09-01

    Because of the radionuclide long half-life, Sr90+Y90, plane or concave sources, utilized in brachytherapy, have to be calibrated initially by the manufacturer and then routinely while they are utilized. Plane applicators can be calibrated against a conventional extrapolation chamber, but concave sources, because of their geometry, should be calibrated using relative dosimeters, as thermoluminescent (TL) materials. Thin CaSO4:Dy pellets are produced at IPEN specially for beta radiation detection. Previous works showed the feasibility of this material in the dosimetry of Sr90+Y90 sources in a wide range of absorbed dose in air. The aim of this work was to study the usefulness of these pellets for the calibration of a Sr90+Y90 concave applicator. To reach this objective, a special phantom was designed and manufactured in PTFE with semi spherical geometry. Because of the dependence of the TL response on the mass of the pellet, the response of each pellet was normalized by its mass in order to reduce the dispersion on TL response. Important characteristics of this material were obtained in reference of a standard Sr90+Y90 source, and the pellets were calibrated against a plane applicator; then they were utilized to calibrate the concave applicator.

  9. Spectral Irradiance Calibration in the Infrared. 11; Comparison of (alpha) Bootis and 1 Ceres with a Laboratory Standard

    NASA Technical Reports Server (NTRS)

    Witteborn, Fred C.; Cohen, Martin; Bregman, Jesse D.; Wooden, Diane H.; Heere, Karen; Shirley, Eric L.

    1999-01-01

    Infrared spectra of two celestial objects frequently used as flux standards are calibrated against an absolute laboratory flux standard at a spectral resolving power of 100 to 200. The spectrum of the KI.5 III star alpha Boo is measured from 3 to 30 microns, and that of the C-type asteroid 1 Ceres from 5 to 30 microns. While these "standard" spectra do not have the apparent precision of those based on calculated models, they do not require the assumptions involved in theoretical models of stars and asteroids. Specifically, they provide a model-independent means of calibrating celestial flux in the spectral range from 12 to 30 microns, where accurate absolute photometry is not available. The agreement found between the spectral shapes of alpha Boo and Ceres based on laboratory standards and those based on observed ratios to alpha CMa (Sirius) and alpha Lyr (Vega), flux-calibrated by theoretical modeling of these hot stars, strengthens our confidence in the applicability of the stellar models as primary irradiance standards.

  10. Spectral Irradiance Calibration in the Infrared 11: Comparison of (alpha) Boo and 1 Ceres with a Laboratory Standard

    NASA Technical Reports Server (NTRS)

    Witteborn, Fred C.; Cohen, Martin; Bregman, Jess D.; Wooden, Diane; Heere, Karen; Shirley, Eric L.

    1998-01-01

    Infrared spectra of two celestial objects frequently used as flux standards are calibrated against an absolute laboratory flux standard at a spectral resolving power of 100 to 200. The spectrum of the K1.5III star, alpha Boo, is measured from 3 microns to 30 microns and that of the C-type asteroid, 1 Ceres, from 5 microns to 30 microns. While these 'standard' spectra do not have the apparent precision of those based on calculated models, they do not require the assumptions involved in theoretical models of stars and asteroids. Specifically they provide a model-independent means of calibrating celestial flux in the spectral range from 12 microns to 30 microns where accurate absolute photometry is not available. The agreement found between the spectral shapes of alpha Boo and Ceres based on laboratory standards, and those based on observed ratios to alpha CMa (Sirius) and alpha Lyr (Vega), flux calibrated by theoretical modeling of these hot stars strengthens our confidence in the applicability of the stellar models as primary irradiance standards.

  11. Spectroradiometric calibration techniques in the far ultraviolet - A stable emission source for the Lyman bands of molecular hydrogen

    NASA Technical Reports Server (NTRS)

    Fastie, W. G.; Kerr, D. E.

    1975-01-01

    The problems associated with making accurate spectroradiometric measurements in the far UV region are sketched briefly. The equipment and methods that were developed for providing absolute sensitivity calibration of an Apollo 17 far UV spectrometer are described. The absolute reference standards were photoelectric diodes calibrated at the National Bureau of Standards. A complete vacuum optical facility, which included a premonochromator and stable UV light sources, was developed to calibrate the Apollo 17 instrument, and it has been used for a number of other tasks. Absolute radiometric calibrations between about 1200 and 1700 A were performed with an absolute accuracy of + or - 10%. The light source, which was designed to provide a very stable light output, is a low-pressure molecular hydrogen lamp in which the pressure is stabilized by thermal control of uranium hydride powder.-

  12. Calibration and Sequence Development Status for the Sample Analysis at Mars Investigation on the Mars Science Laboratory

    NASA Technical Reports Server (NTRS)

    Mahaffy, Paul R.

    2012-01-01

    The measurement goals of the Sample Analysis at Mars (SAM) instrument suite on the "Curiosity" Rover of the Mars Science Laboratory (MSL) include chemical and isotopic analysis of organic and inorganic volatiles for both atmospheric and solid samples [1,2]. SAM directly supports the ambitious goals of the MSL mission to provide a quantitative assessment of habitability and preservation in Gale crater by means of a range of chemical and geological measurements [3]. The SAM FM combined calibration and environmental testing took place primarily in 2010 with a limited set of tests implemented after integration into the rover in January 2011. The scope of SAM FM testing was limited both to preserve SAM consumables such as life time of its electromechanical elements and to minimize the level of terrestrial contamination in the SAM instrument. A more comprehensive calibration of a SAM-like suite of instruments will be implemented in 2012 with calibration runs planned for the SAM testbed. The SAM Testbed is nearly identical to the SAM FM and operates in a ambient pressure chamber. The SAM Instrument Suite: SAM's instruments are a Quadrupole Mass Spectrometer (QMS), a 6-column Gas Chromatograph (GC), and a 2-channel Tunable Laser Spectrometer (TLS). Gas Chromatography Mass Spectrometry is designed for identification of even trace organic compounds. The TLS [5] secures the C, H, and O isotopic composition in carbon dioxide, water, and methane. Sieved materials are delivered from the MSL sample acquisition and processing system to one of68 cups of the Sample Manipulation System (SMS). 59 of these cups are fabricated from inert quartz. After sample delivery, a cup is inserted into one of 2 ovens for evolved gas analysis (EGA ambient to >9500C) by the QMS and TLS. A portion of the gas released can be trapped and subsequently analyzed by GCMS. Nine sealed cups contain liquid solvents and chemical derivatization or thermochemolysis agents to extract and transform polar molecules

  13. Impact of assay parameters on the accuracy of free PSA test: source and stability of calibrator, calibration curve fitting, and level of total PSA in the serum.

    PubMed

    Liu, G H; Wu, J T

    1998-01-01

    The measurement of PSA is recommended for men over 50 years of age for screening of prostate cancer. However, proper differentiation of prostate cancer from benign prostate hyperplasia (BPH) relies on an accurate measurement of free PSA (fPSA) and a correct calculation of percent fPSA. Because of the extremely low concentration of fPSA in the serum, any slight deviation from its true value may produce large errors in percent fPSA calculated. Therefore, we undertook a study examining carefully those parameters of the fPSA assay which might affect the fPSA determination. We found that the integrity of the calibrator, the computer curve-fitting program selected, the source of the calibrator, and the total PSA or fPSA + PSA complexes (tPSA) concentration of the specimen all had an impact on the accuracy of the fPSA value assayed. We found that an examination of the slope of the calibration curve was important to reveal whether the calibrator had or had not been denatured during storage. We also found that the 4-parameter cure fitting program was best suited for plotting the fPSA calibration curve. The calibrator we isolated from LNCaP cells was acceptable for our assay because it had an affinity for the assay antibody very similar to that of serum fPSA. We also determined the effect of tPSA concentration on the fPSA determinations and found that within the concentration range of 4-10 ng/mL the impact on the percent fPSA calculated was not significant. We believe that our assay produces accurate fPSA values when all these assay parameters are well controlled.

  14. Exploring a Black Body Source as an Absolute Radiometric Calibration Standard and Comparison with a NIST Traced Lamp Standard

    NASA Technical Reports Server (NTRS)

    Green, Robert O.; Chrien, Thomas; Sarture, Chuck

    2001-01-01

    Radiometric calibration of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) is required for the scientific research and application objectives pursued with the spectroscopic measurements. Specifically calibration is required for: inter-comparison of AVIRIS data measured at different locations and at different times; analysis of AVIRIS data with data measured by other instruments; and analysis of AVIRIS data in conjunction with computer models. The primary effect of radiometric calibration is conversion of AVIRIS instrument response values (digitized numbers, or DN) to units of absolute radiance. For example, a figure shows the instrument response spectrum measured by AVIRIS over a portion of Rogers Dry Lake, California, and another figure shows the same spectrum calibrated to radiance. Only the calibrated spectrum may be quantitatively analyzed for science research and application objectives. Since the initial development of the AVIRIS instrument-radiometric calibration has been based upon a 1000-W irradiance lamp with a calibration traced to the National Institute of Standards and Technology (NIST). There are several advantages to this irradiance-lamp calibration approach. First, the considerable effort of NIST backs up the calibration. Second, by changing the distance to the lamp, the output can closely span the radiance levels measured by AVIRIS. Third, this type of standard is widely used. Fourth, these calibrated lamps are comparatively inexpensive. Conversely, there are several disadvantages to this approach as well. First, the lamp is not a primary standard. Second, the lamp output characteristics may change in an unknown manner through time. Third, it is difficult to assess, constrain, or improve the calibration uncertainty delivered with the lamp. In an attempt to explore the effect and potentially address some of these disadvantages a set of analyses and measurements comparing an irradiance lamp with a black-body source have been completed

  15. Analysis and Calibration of Sources of Electronic Error in PSD Sensor Response

    PubMed Central

    Rodríguez-Navarro, David; Lázaro-Galilea, José Luis; Bravo-Muñoz, Ignacio; Gardel-Vicente, Alfredo; Tsirigotis, Georgios

    2016-01-01

    In order to obtain very precise measurements of the position of agents located at a considerable distance using a sensor system based on position sensitive detectors (PSD), it is necessary to analyze and mitigate the factors that generate substantial errors in the system’s response. These sources of error can be divided into electronic and geometric factors. The former stem from the nature and construction of the PSD as well as the performance, tolerances and electronic response of the system, while the latter are related to the sensor’s optical system. Here, we focus solely on the electrical effects, since the study, analysis and correction of these are a prerequisite for subsequently addressing geometric errors. A simple calibration method is proposed, which considers PSD response, component tolerances, temperature variations, signal frequency used, signal to noise ratio (SNR), suboptimal operational amplifier parameters, and analog to digital converter (ADC) quantitation SNRQ, etc. Following an analysis of these effects and calibration of the sensor, it was possible to correct the errors, thus rendering the effects negligible, as reported in the results section. PMID:27136562

  16. Analysis and Calibration of Sources of Electronic Error in PSD Sensor Response.

    PubMed

    Rodríguez-Navarro, David; Lázaro-Galilea, José Luis; Bravo-Muñoz, Ignacio; Gardel-Vicente, Alfredo; Tsirigotis, Georgios

    2016-01-01

    In order to obtain very precise measurements of the position of agents located at a considerable distance using a sensor system based on position sensitive detectors (PSD), it is necessary to analyze and mitigate the factors that generate substantial errors in the system's response. These sources of error can be divided into electronic and geometric factors. The former stem from the nature and construction of the PSD as well as the performance, tolerances and electronic response of the system, while the latter are related to the sensor's optical system. Here, we focus solely on the electrical effects, since the study, analysis and correction of these are a prerequisite for subsequently addressing geometric errors. A simple calibration method is proposed, which considers PSD response, component tolerances, temperature variations, signal frequency used, signal to noise ratio (SNR), suboptimal operational amplifier parameters, and analog to digital converter (ADC) quantitation SNRQ, etc. Following an analysis of these effects and calibration of the sensor, it was possible to correct the errors, thus rendering the effects negligible, as reported in the results section.

  17. GOSAT-OCO-2 synergetic CO2 observations over calibration & validation sites and large emission sources

    NASA Astrophysics Data System (ADS)

    Kuze, A.; Shiomi, K.; Suto, H.; Kataoka, F.; Crisp, D.; Schwandner, F. M.; Bruegge, C. J.; Taylor, T.; Kawakami, S.

    2015-12-01

    GOSAT and OCO-2 have different observation strategies. TANSO-FTS onboard GOSAT has wide spectral coverage from SWIR to TIR and an agile pointing system at the expense of spatial context, while OCO-2 targets CO2with higher spatial resolution using imaging grating spectrometers. Since the early phase of the two projects, both teams have worked in calibration and validation to demonstrate the effectiveness of satellite greenhouse gases observation. In 2008, the pre-launch cross-calibration agreement between GOSAT and OCO radiometers was better than 2% when measuring the traceable GOSAT calibration sphere (Sakuma et. al, 2010). Since GOSAT's launch in 2009, annual joint vicarious calibration campaigns at the Railroad Valley (RRV) playa have estimated radiometric degradation factors with time at an uncertainty of 7%. (Kuze et al., 2014). After OCO-2 launch, two independent measurements can now be compared to distinguish common forward calculation errors such as molecule absorption line parameters, solar lines and light-path modification by aerosol scattering from instrument-specific errors. On 25 Mach 2015, both GOSAT and OCO-2 targeted RRV simultaneously. The measured radiance spectra at the top of the atmosphere agree within 5% for all common bands. On June 29 and July 1 during the 7th RRV campaign, coincidence observation of GOSAT, OCO-2, AJAX airplane, radiosonde, and FTS and radiometers on the ground, provided surface albedo, BRDF, temperature, humidity CO2 and CH4 density to demonstrate consistency between forward radiative transfer calculation and satellite measured data. Both GOSAT and OCO-2 have been regularly targeting the TCCON site at Lamont and large emission sources such as mega cities and oil fields and glint over the ocean. Retrieved parameters such as surface albedo, pressure, column averaged mole fraction and aerosol related parameters can be compared firstly where aerosol optical thickness is low and topography is flat, and then over aerosol

  18. Medicina array demonstrator: calibration and radiation pattern characterization using a UAV-mounted radio-frequency source

    NASA Astrophysics Data System (ADS)

    Pupillo, G.; Naldi, G.; Bianchi, G.; Mattana, A.; Monari, J.; Perini, F.; Poloni, M.; Schiaffino, M.; Bolli, P.; Lingua, A.; Aicardi, I.; Bendea, H.; Maschio, P.; Piras, M.; Virone, G.; Paonessa, F.; Farooqui, Z.; Tibaldi, A.; Addamo, G.; Peverini, O. A.; Tascone, R.; Wijnholds, S. J.

    2015-06-01

    One of the most challenging aspects of the new-generation Low-Frequency Aperture Array (LFAA) radio telescopes is instrument calibration. The operational LOw-Frequency ARray (LOFAR) instrument and the future LFAA element of the Square Kilometre Array (SKA) require advanced calibration techniques to reach the expected outstanding performance. In this framework, a small array, called Medicina Array Demonstrator (MAD), has been designed and installed in Italy to provide a test bench for antenna characterization and calibration techniques based on a flying artificial test source. A radio-frequency tone is transmitted through a dipole antenna mounted on a micro Unmanned Aerial Vehicle (UAV) (hexacopter) and received by each element of the array. A modern digital FPGA-based back-end is responsible for both data-acquisition and data-reduction. A simple amplitude and phase equalization algorithm is exploited for array calibration owing to the high stability and accuracy of the developed artificial test source. Both the measured embedded element patterns and calibrated array patterns are found to be in good agreement with the simulated data. The successful measurement campaign has demonstrated that a UAV-mounted test source provides a means to accurately validate and calibrate the full-polarized response of an antenna/array in operating conditions, including consequently effects like mutual coupling between the array elements and contribution of the environment to the antenna patterns. A similar system can therefore find a future application in the SKA-LFAA context.

  19. Laser ion source activities at Brookhaven National Laboratory

    DOE PAGES

    Kanesue, Takeshi; Okamura, Masahiro

    2015-07-31

    In Brookhaven National Laboratory (BNL), we have been developing laser ion sources for diverse accelerators. Tabletop Nd:YAG lasers with up to several Joules of energy are mainly used to create ablation plasmas for stable operations. The obtained charge states depend on laser power density and target species. Two types of ion extraction schemes, Direct Plasma Injection Scheme (DPIS) and conventional static extraction, are used depending on application. We optimized and select a suitable laser irradiation condition and a beam extraction scheme to meet the requirement of the following accelerator system. We have demonstrated to accelerate more than 5 x 1010more » of C6+ ions using the DPIS. We successfully commissioned low charge ion beam provider to the user facilities in BNL. As a result, to achieve higher current, higher charge state and lower emittance, further studies will continue.« less

  20. Laser ion source activities at Brookhaven National Laboratory

    SciTech Connect

    Kanesue, Takeshi; Okamura, Masahiro

    2015-07-31

    In Brookhaven National Laboratory (BNL), we have been developing laser ion sources for diverse accelerators. Tabletop Nd:YAG lasers with up to several Joules of energy are mainly used to create ablation plasmas for stable operations. The obtained charge states depend on laser power density and target species. Two types of ion extraction schemes, Direct Plasma Injection Scheme (DPIS) and conventional static extraction, are used depending on application. We optimized and select a suitable laser irradiation condition and a beam extraction scheme to meet the requirement of the following accelerator system. We have demonstrated to accelerate more than 5 x 1010 of C6+ ions using the DPIS. We successfully commissioned low charge ion beam provider to the user facilities in BNL. As a result, to achieve higher current, higher charge state and lower emittance, further studies will continue.

  1. Method to calibrate phase fluctuation in polarization-sensitive swept-source optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Lu, Zenghai; Kasaragod, Deepa K.; Matcher, Stephen J.

    2011-07-01

    We present a phase fluctuation calibration method for polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) using continuous polarization modulation. The method uses a low-voltage broadband polarization modulator driven by a synchronized sinusoidal burst waveform rather than an asynchronous waveform, together with the removal of the global phases of the measured Jones matrices by the use of matrix normalization. This makes it possible to average the measured Jones matrices to remove the artifact due to the speckle noise of the signal in the sample without introducing auxiliary optical components into the sample arm. This method was validated on measurements of an equine tendon sample by the PS-SS-OCT system.

  2. Calibration Of A KrF Laser-Plasma Source For X-Ray Microscopy Applications

    NASA Astrophysics Data System (ADS)

    Turcu, I. C. E.; O'Neill, F.; Zammit, U.; Al-Hadithi, Y.; Eason, R. W.; Rogayski, A. M.; Hills, C. P. B.; Michette, A. G.

    1988-02-01

    Plasma X-ray sources for biological microscopy in the water-window have been produced by focusing tige 200 3, 50 ns Sprit q KrF laser onto carbon targets at irradiance between 2.2 x 10" W/cm4 and 3.7 x 10i3W/cm. Absolute measurements of X-ray production have been made using a calibrated, vacuum X-ray diode detector. A peak conversion efficiency . 10% is measured from KrF laseri)Tight tcto wate-window X-rays at 280 eV < hv < 530 eV for a target irradiance . 1 x x 10 W/cm'. Some measurements with gold and tungsten targets give conversion efficiencies 2$25% at a similar laser irradiance.

  3. Calibration of a fugitive emission rate measurement of an area source.

    PubMed

    Wong, Colin L Y; Ramkellawan, Jeffrey

    2013-11-01

    A major challenge to measuring fugitive emission rates from large area sources, such as landfills or tailings ponds, has been the establishment of the accuracy of such methods, or of a particular measurement. When such measurements are carried out, they are invariably associated with a relatively high degree of uncertainty. The Airborne Matter Mapping (AMM) method is a new method of measuring fugitive emission rates that can be applied to large area sources. The method was applied to the measurement of methane emissions from a landfill to assess the potential accuracy of the method, and the measurement process was calibrated to increase confidence in the measured value. First, a measured rate of methane from a gas cylinder was released from near the center of the landfill and the AMM method was applied to measure the methane flow rate across a measurement surface. Then, the AMM method was performed a second time along the same measurement surface without the intentional release of methane. The difference of the flow rates across the measurement surface were then compared with the measured rate of methane released from the gas cylinder. The relatively small difference of -5.7% between the flow rates, relative to the methane release rate from the gas cylinder provides confidence in the accuracy of this AMM method measurement. An adjustment to the AMM method analysis was made such that the difference between the flow rates was negligible, which resulted in a calibrated measurement of the methane emission rate from the landfill of 0.87 g/sec.

  4. GT0 Explosion Sources for IMS Infrasound Calibration: Charge Design and Yield Estimation from Near-source Observations

    NASA Astrophysics Data System (ADS)

    Gitterman, Y.; Hofstetter, R.

    2014-03-01

    Three large-scale on-surface explosions were conducted by the Geophysical Institute of Israel (GII) at the Sayarim Military Range, Negev desert, Israel: about 82 tons of strong high explosives in August 2009, and two explosions of about 10 and 100 tons of ANFO explosives in January 2011. It was a collaborative effort between Israel, CTBTO, USA and several European countries, with the main goal to provide fully controlled ground truth (GT0) infrasound sources, monitored by extensive observations, for calibration of International Monitoring System (IMS) infrasound stations in Europe, Middle East and Asia. In all shots, the explosives were assembled like a pyramid/hemisphere on dry desert alluvium, with a complicated explosion design, different from the ideal homogenous hemisphere used in similar experiments in the past. Strong boosters and an upward charge detonation scheme were applied to provide more energy radiated to the atmosphere. Under these conditions the evaluation of the actual explosion yield, an important source parameter, is crucial for the GT0 calibration experiment. Audio-visual, air-shock and acoustic records were utilized for interpretation of observed unique blast effects, and for determination of blast wave parameters suited for yield estimation and the associated relationships. High-pressure gauges were deployed at 100-600 m to record air-blast properties, evaluate the efficiency of the charge design and energy generation, and provide a reliable estimation of the charge yield. The yield estimators, based on empirical scaled relations for well-known basic air-blast parameters—the peak pressure, impulse and positive phase duration, as well as on the crater dimensions and seismic magnitudes, were analyzed. A novel empirical scaled relationship for the little-known secondary shock delay was developed, consistent for broad ranges of ANFO charges and distances, which facilitates using this stable and reliable air-blast parameter as a new potential

  5. Modifications of the X-ray source and monitor at the X-ray Calibration Facility

    NASA Technical Reports Server (NTRS)

    Newbolt, W. Barlow

    1986-01-01

    In order to test the instruments aboard the Advanced X-ray Astrophysics Facility (AXAF) some modifications will need to be made in the X-ray Calibration Facility at Marshall. Several of these modifications involve the X-ray source and the monitor. The source was redesigned to increase the spectral purity of the beam and decrease its polarization by minimizing the number of bremsstrahlung photons in the beam. This was accomplished by utilizing an annular electron gun which allowed the beam to take off antiparallel to the direction at which electrons are incident on the anode. Two other features of the source are the conical anode which decreases the effective spot size and a rotatable anode and filter wheel which allow the operator to change targets without breaking vacuum. The monitor is an important part of the facility because it is used to determine the X-ray flux at the target. A commercially available solid-state detector, Si(Li), should be used along with appropriate proportional counters for monitoring. This detector will be particularly useful when energy or wavelength dispersive instruments are tested because of its good resolution.

  6. Broadband calibration of the R/V Marcus G. Langseth four-string seismic sources

    NASA Astrophysics Data System (ADS)

    Tolstoy, M.; Diebold, J.; Doermann, L.; Nooner, S.; Webb, S. C.; Bohnenstiehl, D. R.; Crone, T. J.; Holmes, R. C.

    2009-08-01

    The R/V Marcus G. Langseth is the first 3-D seismic vessel operated by the U.S. academic community. With up to a four-string, 36-element source and four 6-km-long solid state hydrophone arrays, this vessel promises significant new insights into Earth science processes. The potential impact of anthropogenic sound sources on marine life is an important topic to the marine seismic community. To ensure that operations fully comply with existing and future marine mammal permitting requirements, a calibration experiment was conducted in the Gulf of Mexico in 2007-2008. Results are presented from deep (˜1.6 km) and shallow (˜50 m) water sites, obtained using the full 36-element (6600 cubic inches) seismic source. This array configuration will require the largest safety radii, and the deep and shallow sites provide two contrasting operational environments. Results show that safety radii and the offset between root-mean-square and sound exposure level measurements were highly dependent on water depth.

  7. Design, construction, and use of a shipping case for radioactive sources used in the calibration of portal monitors in the radiation portal monitoring project

    SciTech Connect

    Lepel, Elwood A.; Hensley, Walter K.

    2009-12-01

    Pacific Northwest National Laboratory is working with US Customs and Border Protection to assist in the installation of radiation portal monitors. We need to provide radioactive sources – both gamma- and neutron-emitting – to ports of entry where the monitors are being installed. The monitors must be calibrated to verify proper operation and detection sensitivity. We designed a portable source-shipping case using numerical modeling to predict the neutron dose rate at the case’s surface. The shipping case including radioactive sources meets the DOT requirements for “limited quantity.” Over 300 shipments, domestic and international, were made in FY2008 using this type of shipping case.

  8. Dual-channel photoacoustic hygrometer for airborne measurements: background, calibration, laboratory and in-flight intercomparison tests

    NASA Astrophysics Data System (ADS)

    Tátrai, D.; Bozóki, Z.; Smit, H.; Rolf, C.; Spelten, N.; Krämer, M.; Filges, A.; Gerbig, C.; Gulyás, G.; Szabó, G.

    2015-01-01

    This paper describes a tunable diode laser-based dual-channel photoacoustic (PA) humidity measuring system primarily designed for aircraft-based environment research. It is calibrated for total pressure and water vapor (WV) volume mixing ratios (VMRs) possible during airborne applications. WV VMR is calculated by using pressure-dependent calibration curves and a cubic spline interpolation method. Coverage of the entire atmospheric humidity concentration range that might be encountered during airborne measurements is facilitated by applying an automated sensitivity mode switching algorithm. The calibrated PA system was validated through laboratory and airborne intercomparisons, which proved that the repeatability, the estimated accuracy and the response time of the system are 0.5 ppmV or 0.5% of the actual reading (whichever value is the greater), 5% of the actual reading within the VMR range of 1-12 000 ppmV and 2 s, respectively. The upper detection limit of the system is theoretically about 85 000 ppmV, limited only by condensation of water vapor on the walls of the 318 K heated PA cells and inlet lines, and was experimentally verified up to 20 000 ppmV. The unique advantage of the presented system is its applicability for simultaneous water vapor and total water volume mixing ratio measurements.

  9. A radio telescope for the calibration of radio sources at 32 gigahertz

    NASA Technical Reports Server (NTRS)

    Gatti, M. S.; Stewart, S. R.; Bowen, J. G.; Paulsen, E. B.

    1994-01-01

    A 1.5-m-diameter radio telescope has been designed, developed, and assembled to directly measure the flux density of radio sources in the 32-GHz (Ka-band) frequency band. The main goal of the design and development was to provide a system that could yield the greatest absolute accuracy yet possible with such a system. The accuracy of the measurements have a heritage that is traceable to the National Institute of Standards and Technology. At the present time, the absolute accuracy of flux density measurements provided by this telescope system, during Venus observations at nearly closest approach to Earth, is plus or minus 5 percent, with an associated precision of plus or minus 2 percent. Combining a cooled high-electron mobility transistor low-noise amplifier, twin-beam Dicke switching antenna, and accurate positioning system resulted in a state-of-the-art system at 32 GHz. This article describes the design and performance of the system as it was delivered to the Owens Valley Radio Observatory to support direct calibrations of the strongest radio sources at Ka-band.

  10. Depth and source mechanism estimation for special event analysis, event screening, and regional calibration

    SciTech Connect

    Goldstein, P; Dodge, D; Ichinose, Rodgers, A; Bhattacharyya, B; Leach, R

    1999-07-23

    We have summarized the advantages and disadvantages of a variety of techniques for depth and mechanism estimation and suggest that significant work remains to be done for events with magnitudes of interest for test ban monitoring. We also describe a new, waveform modeling-based tool for fast and accurate, high-resolution depth and mechanism estimation. Significant features of this tool include its speed and accuracy and its applicability at relatively high frequencies. These features allow a user to rapidly determine accurate, high-resolution depth estimates and constraints on source mechanism for relatively small magnitude (mb-4.5) events. Based on the accuracy of depth estimates obtained with this tool, we conclude it is useful for both the analysis of unusual or suspect events and for event screening. We also find that this tool provides significant constraints on source mechanism and have used it to develop ''ground-truth'' estimates of depth and mechanism for a set of events in the Middle East and North Africa. These ''ground-truth'' depths and mechanisms should be useful for regional calibration.

  11. Real-time particle monitor calibration factors and PM2.5 emission factors for multiple indoor sources.

    PubMed

    Dacunto, Philip J; Cheng, Kai-Chung; Acevedo-Bolton, Viviana; Jiang, Ruo-Ting; Klepeis, Neil E; Repace, James L; Ott, Wayne R; Hildemann, Lynn M

    2013-08-01

    Indoor sources can greatly contribute to personal exposure to particulate matter less than 2.5 μm in diameter (PM2.5). To accurately assess PM2.5 mass emission factors and concentrations, real-time particle monitors must be calibrated for individual sources. Sixty-six experiments were conducted with a common, real-time laser photometer (TSI SidePak™ Model AM510 Personal Aerosol Monitor) and a filter-based PM2.5 gravimetric sampler to quantify the monitor calibration factors (CFs), and to estimate emission factors for common indoor sources including cigarettes, incense, cooking, candles, and fireplaces. Calibration factors for these indoor sources were all significantly less than the factory-set CF of 1.0, ranging from 0.32 (cigarette smoke) to 0.70 (hamburger). Stick incense had a CF of 0.35, while fireplace emissions ranged from 0.44-0.47. Cooking source CFs ranged from 0.41 (fried bacon) to 0.65-0.70 (fried pork chops, salmon, and hamburger). The CFs of combined sources (e.g., cooking and cigarette emissions mixed) were linear combinations of the CFs of the component sources. The highest PM2.5 emission factors per time period were from burned foods and fireplaces (15-16 mg min(-1)), and the lowest from cooking foods such as pizza and ground beef (0.1-0.2 mg min(-1)). PMID:23784066

  12. Laboratory data on coarse-sediment transport for bedload-sampler calibrations

    USGS Publications Warehouse

    Hubbell, David Wellington; Stevens, H.H.; Skinner, J.V.; Beverage, J.P.

    1987-01-01

    A unique facility capable of recirculating and continuously measuring the transport rates of sediment particles ranging in size from about 1 to 75 millimeters in diameter was designed and used in an extensive program involving the calibration of bedload samplers. The facility consisted of a 9-footwide by 6-foot-deep by 272-foot-long rectangular channel that incorporated seven automated collection pans and a sedimentreturn system. The collection pans accumulated, weighed, and periodically dumped bedload falling through a slot in the channel floor. Variations of the Helley-Smith bedload sampler, an Arnhem sampler, and two VUV-type samplers were used to obtain transport rates for comparison with rates measured at the bedload slot (trap). Tests were conducted under 20 different hydraulic and sedimentologic conditions (runs) with 3 uniform-size bed materials and a bed-material mixture. Hydraulic and sedimentologic data collected concurrently with the calibration measurements are described and, in part, summarized in tabular and graphic form. Tables indicate the extent of the data, which are available on magnetic media. The information includes sediment-transport rates; particle-size distributions; water discharges, depths, and slopes; longitudinal profiles of streambed-surface elevations; and temporal records of streambed-surface elevations at fixed locations.

  13. Laboratory Testing and Calibration of the Nuclei-Mode Aerosol Size Spectrometer

    NASA Technical Reports Server (NTRS)

    Brock, Charles A.

    1999-01-01

    This grant was awarded to complete testing and calibration of a new instrument, the nuclei-mode aerosol size spectrometer (N-MASS), following its use in the WB-57F Aerosol Measurement (WAM) campaign in early 1998. The N-MASS measures the size distribution of particles in the 4-60 nm diameter range with 1-Hz response at typical free tropospheric conditions. Specific tasks to have been completed under the auspices of this award were: 1) to experimentally determine the instrumental sampling efficiency; 2) to determine the effects of varying temperatures and flows on N-MASS performance; and 3) to calibrate the N-MASS at typical flight conditions as operated in WAM. The work outlined above has been completed, and a journal manuscript based on this work and that describes the performance of the N-MASS is in preparation. Following a brief description of the principles of operation of the instrument, the major findings of this study are described.

  14. Laboratory calibrations of the PP-SESAME instrument on Philae for measuring the cometary surface permittivity

    NASA Astrophysics Data System (ADS)

    Hamelin, M.; Le Gall, A.; Caujolle-Bert, S.; Schmidt, W.; Grard, R.; Laasko, H.; Ciarletti, V.; Seidensticker, K.

    2013-09-01

    The complex permittivity of terrestrial and planetary grounds can be derived from Mutual Impedance (MI) measurements using a four-electrode array [1]; the system is working at a fixed frequency with the electrodes not necessarily in contact with the ground and with a dedicated electronic system. This concept was used to build the Permittivity Probe (PP) as part of the SESAME experiment of the Philae Rosetta cometary lander. However severe constraints due to the payload facilities and to the particular environment lead to the actual design of the instrument. Unfortunately it was not possible to perform calibrations of the full system before lauch and the ground model consists of several parts used by various instruments. Here we report the results of basic calibration tests performed with a model of the Philae Landing Gear built in DLR. These tests involve only the three feet electrodes and a mockup of the the Philae body with very simple and well defined targets for characterizing the instrument. Further measurements on natural targets would be the next step.

  15. Calibrating nonlinear volcano deformation source parameters in FEMs: The pinned mesh perturbation method. (Invited)

    NASA Astrophysics Data System (ADS)

    Masterlark, T.; Stone, J.; Feigl, K.

    2010-12-01

    The internal structure, loading processes, and effective boundary conditions of a volcano control the deformation that we observe at the Earth’s surface. Forward models of these internal structures and processes allow us to predict the surface deformation. In practice, we are faced with the inverse situation of using surface observations (e.g., InSAR and GPS) to characterize the inaccessible internal structures and processes. Distortions of these characteristics are tied to our ability to: 1) identify and resolve the internal structure; 2) simulate the internal processes over a problem domain having this internal structure; and 3) calibrate parameters that describe these internal processes to the observed deformation. Relatively simple analytical solutions for deformation sources (such as a pressurized magma chamber) embedded in a homogeneous, elastic half-space are commonly used to simulate observed volcano deformation, because they are computationally inexpensive, and thus easily integrated into inverse analyses that seek to characterize the source position and magnitude. However, the half-space models generally do not adequately represent internal distributions of material properties and complex geometric configurations, such as topography, of volcano deformational systems. These incompatibilities are known to severely bias both source parameter estimations and forward model calculations of deformation and stress. Alternatively, a Finite Element Model (FEM) can simulate the elastic response to a pressurized magma chamber over a domain having arbitrary geometry and distribution of material properties. However, the ability to impose perturbations of the source position parameters and automatically reconstruct an acceptable mesh has been an obstacle to implementing FEM-based nonlinear inverse methods to estimate the position of a deformation source. Using InSAR-observed deflation of Okmok volcano, Alaska, during its 1997 eruption as an example, we present the

  16. An electrochemical method for the preparation of 63Ni source for the calibration of thermoluminescence dosimeter (TLD).

    PubMed

    Kumar, Manoj; Udhayakumar, J; Gandhi, Shyamala S; Satpati, A K; Dash, Ashutosh; Venkatesh, Meera

    2009-06-01

    A novel electrochemical approach for preparation of (63)Ni sources for their application as check-light source for the calibration of thermo luminescence dosimeters (TLD) is described here. Required amount of (63)Ni on a copper substrate could be deposited by optimizing the experimental parameters such as current density, time of deposition, pH of the electrolyte and nickel ion concentration in the bath. (63)Ni sources of strength approximately 3.7 MBq could be prepared by electrodeposition at constant current on the copper matrix. Quality assurance tests to ensure nonleachability, uniform distribution of activity and stability of the sources that are necessary before application were performed.

  17. Sources of systematic error in calibrated BOLD based mapping of baseline oxygen extraction fraction.

    PubMed

    Blockley, Nicholas P; Griffeth, Valerie E M; Stone, Alan J; Hare, Hannah V; Bulte, Daniel P

    2015-11-15

    Recently a new class of calibrated blood oxygen level dependent (BOLD) functional magnetic resonance imaging (MRI) methods were introduced to quantitatively measure the baseline oxygen extraction fraction (OEF). These methods rely on two respiratory challenges and a mathematical model of the resultant changes in the BOLD functional MRI signal to estimate the OEF. However, this mathematical model does not include all of the effects that contribute to the BOLD signal, it relies on several physiological assumptions and it may be affected by intersubject physiological variability. The aim of this study was to investigate these sources of systematic error and their effect on estimating the OEF. This was achieved through simulation using a detailed model of the BOLD signal. Large ranges for intersubject variability in baseline physiological parameters such as haematocrit and cerebral blood volume were considered. Despite this the uncertainty in the relationship between the measured BOLD signals and the OEF was relatively low. Investigations of the physiological assumptions that underlie the mathematical model revealed that OEF measurements are likely to be overestimated if oxygen metabolism changes during hypercapnia or cerebral blood flow changes under hyperoxia. Hypoxic hypoxia was predicted to result in an underestimation of the OEF, whilst anaemic hypoxia was found to have only a minimal effect.

  18. Neutron Arm Study and Calibration for the GEn Experiment at Thomas Jefferson National Laboratory

    SciTech Connect

    Ngo, Timothy

    2007-07-01

    The measurement of the neutron electric form factor, G$n\\atop{e}$, will allow us to solve indirectly for the quark charge distribution inside of the neutron. With the equipment at Jefferson Lab we have measured G$n\\atop{e}$ at four momentum transfer values of Q2 at 1.3, 2.4 and 3.4 (GeV/c)2 using a polarized electron beam and polarized Helium target. The scattered electrons off of the Helium target are detected in the BigBite spectrometer and the recoiling neutrons from the Helium are detected in the Neutron Arm, which is composed of an array of scintillators. The main focus of this thesis will be devoted to the geometry, timing and energy calibrations of the Neutron Arm.

  19. Dissolved plume attenuation with DNAPL source remediation, aqueous decay and volatilization--analytical solution, model calibration and prediction uncertainty.

    PubMed

    Parker, Jack C; Park, Eungyu; Tang, Guoping

    2008-11-14

    A vertically-integrated analytical model for dissolved phase transport is described that considers a time-dependent DNAPL source based on the upscaled dissolution kinetics model of Parker and Park with extensions to consider time-dependent source zone biodecay, partial source mass reduction, and remediation-enhanced source dissolution kinetics. The model also considers spatial variability in aqueous plume decay, which is treated as the sum of aqueous biodecay and volatilization due to diffusive transport and barometric pumping through the unsaturated zone. The model is implemented in Excel/VBA coupled with (1) an inverse solution that utilizes prior information on model parameters and their uncertainty to condition the solution, and (2) an error analysis module that computes parameter covariances and total prediction uncertainty due to regression error and parameter uncertainty. A hypothetical case study is presented to evaluate the feasibility of calibrating the model from limited noisy field data. The results indicate that prediction uncertainty increases significantly over time following calibration, primarily due to propagation of parameter uncertainty. However, differences between the predicted performance of source zone partial mass reduction and the known true performance were reasonably small. Furthermore, a clear difference is observed between the predicted performance for the remedial action scenario versus that for a no-action scenario, which is consistent with the true system behavior. The results suggest that the model formulation can be effectively utilized to assess monitored natural attenuation and source remediation options if careful attention is given to model calibration and prediction uncertainty issues.

  20. Dissolved plume attenuation with DNAPL source remediation, aqueous decay and volatilization--analytical solution, model calibration and prediction uncertainty.

    PubMed

    Parker, Jack C; Park, Eungyu; Tang, Guoping

    2008-11-14

    A vertically-integrated analytical model for dissolved phase transport is described that considers a time-dependent DNAPL source based on the upscaled dissolution kinetics model of Parker and Park with extensions to consider time-dependent source zone biodecay, partial source mass reduction, and remediation-enhanced source dissolution kinetics. The model also considers spatial variability in aqueous plume decay, which is treated as the sum of aqueous biodecay and volatilization due to diffusive transport and barometric pumping through the unsaturated zone. The model is implemented in Excel/VBA coupled with (1) an inverse solution that utilizes prior information on model parameters and their uncertainty to condition the solution, and (2) an error analysis module that computes parameter covariances and total prediction uncertainty due to regression error and parameter uncertainty. A hypothetical case study is presented to evaluate the feasibility of calibrating the model from limited noisy field data. The results indicate that prediction uncertainty increases significantly over time following calibration, primarily due to propagation of parameter uncertainty. However, differences between the predicted performance of source zone partial mass reduction and the known true performance were reasonably small. Furthermore, a clear difference is observed between the predicted performance for the remedial action scenario versus that for a no-action scenario, which is consistent with the true system behavior. The results suggest that the model formulation can be effectively utilized to assess monitored natural attenuation and source remediation options if careful attention is given to model calibration and prediction uncertainty issues. PMID:18502537

  1. Importance of Temperature Calibration for Sunset Laboratory Carbon Analyzer: NIOSH and IMPROVE Temperature Protocols

    EPA Science Inventory

    The Sunset Laboratory Dual-Optical Carbonaceous Analyzer that simultaneously measures transmission and reflectance signals is widely used in thermal-optical analysis of particulate matter samples. Most often it is used to measure total carbon (TC), organic carbon (OC), and eleme...

  2. Pinon Pine Tree Study, Los Alamos National Laboratory: Source document

    SciTech Connect

    P. R. Fresquez; J. D. Huchton; M. A. Mullen; L. Naranjo, Jr.

    2000-01-01

    One of the dominant tree species growing within and around Los Alamos National Laboratory (LANL), Los Alamos, NM, lands is the pinon pine (Pinus edulis) tree. Pinon pine is used for firewood, fence posts, and building materials and is a source of nuts for food--the seeds are consumed by a wide variety of animals and are also gathered by people in the area and eaten raw or roasted. This study investigated the (1) concentration of {sup 3}H, {sup 137}Cs, {sup 90}Sr, {sup tot}U, {sup 238}Pu, {sup 239,240}Pu, and {sup 241}Am in soils (0- to 12-in. [31 cm] depth underneath the tree), pinon pine shoots (PPS), and pinon pine nuts (PPN) collected from LANL lands and regional background (BG) locations, (2) concentrations of radionuclides in PPN collected in 1977 to present data, (3) committed effective dose equivalent (CEDE) from the ingestion of nuts, and (4) soil to PPS to PPN concentration ratios (CRs). Most radionuclides, with the exception of {sup 3}H in soils, were not significantly higher (p < 0.10) in soils, PPS, and PPN collected from LANL as compared to BG locations, and concentrations of most radionuclides in PPN from LANL have decreased over time. The maximum net CEDE (the CEDE plus two sigma minus BG) at the most conservative ingestion rate (10 lb [4.5 kg]) was 0.0018 mrem (0.018 {micro}Sv). Soil-to-nut CRs for most radionuclides were within the range of default values in the literature for common fruits and vegetables.

  3. Global Inter-Laboratory Fecal Source Identification Methods Comparison Study

    EPA Science Inventory

    Source tracking is key to identifying sources of fecal contamination for remediation as well as risk assessment. Previous intra- and inter-lab studies have investigated the performance of human and cow-associated source tracking markers, as well as library-dependent fecal source ...

  4. Impact of switching to the ICRP-74 neutron flux-to-dose equivalent rate conversion factors at the Sandia National Laboratory Building 818 Neutron Source Range.

    SciTech Connect

    Ward, Dann C.

    2009-03-01

    Sandia National Laboratories (SNL) maintains a neutron calibration facility which supports the calibration, maintenance, and repair of Radiation Protection Instruments. The SNL neutron reference fields are calibrated using the following methodology: Fluence rate is initially established by calculation using the NIST traceable source emission rate (decay corrected). Correction factors for the effects of room return or scatter, and source anisotropy are then developed by using a suitable radiation transport code to model the geometry of the facility. The conventionally true neutron dose rates are then determined using the appropriate fluence-todose equivalent conversion coefficients at several reference positions. This report describes the impact on calculated neutron dose rates of switching from NCRP-38 to CRP-74 neutron flux-todose equivalent rate conversion factors. This switch is driven by recent changes to dosimetry requirements addressed in 10 CFR 835 (Occupational Radiation Protection).

  5. Successful remediation of four uranium calibration pits at Technical Area II, Sandia National Laboratories, Albuquerque, New Mexico, USA

    SciTech Connect

    Conway, R.; Wade, M.; Tharp, T.; Copland, J.

    1994-12-31

    The first remediation of an Environmental Restoration (ER) Project site at Sandia National Laboratories (SNL) was successfully conducted in May and June 1994 at Technical Area II. The removal action involved four Uranium Calibration Pits (UCPs) filled with radioactive or hazardous materials. The concrete culvert pits were used to test and calibrate borehole radiometric logging tools for uranium exploration. The removal action consisted of excavating and containerizing the pit contents and contaminated soil beneath the culverts, removing the four culverts, and backfilling the excavation. Each UCP removal had unique complexities. Sixty 208-L drums of solid radioactive waste and eight 208-L drums of liquid hazardous waste were generated during the VCM. Two of the concrete culverts will be disposed as radioactive waste and two as solid waste. Uranium-238 was detected in UCP-2 ore material at 746 pci/g, and at 59 pci/g in UCP-1 silica sand. UCP-4 was empty; sludge from UCP-3 contained 122 mg/L (ppm) chromium.

  6. Laboratory Simulation of Impacts upon Aluminum Foils of the Stardust Spacecraft: Calibration of Dust Particle Size from Comet Wild 2

    NASA Technical Reports Server (NTRS)

    Kearsley, A. T.; Burchell, M. J.; Horz, F.; Cole, M. J.; Schwandt, C. S.

    2006-01-01

    Metallic aluminium alloy foils exposed on the forward, comet-facing surface of the aerogel tray on the Stardust spacecraft are likely to have been impacted by the same cometary particle population as the dedicated impact sensors and the aerogel collector. The ability of soft aluminium alloy to record hypervelocity impacts as bowl-shaped craters offers an opportunistic substrate for recognition of impacts by particles of a wide potential size range. In contrast to impact surveys conducted on samples from low Earth orbit, the simple encounter geometry for Stardust and Wild 2, with a known and constant spacecraft-particle relative velocity and effective surface-perpendicular impact trajectories, permits closely comparable simulation in laboratory experiments. For a detailed calibration programme we have selected a suite of spherical glass projectiles of uniform density and hardness characteristics, with well-documented particle size range from 10 microns to nearly 100 microns. Light gas gun buckshot firings of these particles at approximately 6km s)exp -1) onto samples of the same foil as employed on Stardust have yielded large numbers of craters. Scanning electron microscopy of both projectiles and impact features has allowed construction of a calibration plot, showing a linear relationship between impacting particle size and impact crater diameter. The close match between our experimental conditions and the Stardust mission encounter parameters should provide another opportunity to measure particle size distributions and fluxes close to the nucleus of Wild 2, independent of the active impact detector instruments aboard the Stardust spacecraft.

  7. A comparison of absolute calibrations of a radiation thermometer based on a monochromator and a tunable source

    SciTech Connect

    Keawprasert, T.; Anhalt, K.; Taubert, D. R.; Sperling, A.; Schuster, M.; Nevas, S.

    2013-09-11

    An LP3 radiation thermometer was absolutely calibrated at a newly developed monochromator-based set-up and the TUneable Lasers in Photometry (TULIP) facility of PTB in the wavelength range from 400 nm to 1100 nm. At both facilities, the spectral radiation of the respective sources irradiates an integrating sphere, thus generating uniform radiance across its precision aperture. The spectral irradiance of the integrating sphere is determined via an effective area of a precision aperture and a Si trap detector, traceable to the primary cryogenic radiometer of PTB. Due to the limited output power from the monochromator, the absolute calibration was performed with the measurement uncertainty of 0.17 % (k= 1), while the respective uncertainty at the TULIP facility is 0.14 %. Calibration results obtained by the two facilities were compared in terms of spectral radiance responsivity, effective wavelength and integral responsivity. It was found that the measurement results in integral responsivity at the both facilities are in agreement within the expanded uncertainty (k= 2). To verify the calibration accuracy, the absolutely calibrated radiation thermometer was used to measure the thermodynamic freezing temperatures of the PTB gold fixed-point blackbody.

  8. A comparison of absolute calibrations of a radiation thermometer based on a monochromator and a tunable source

    NASA Astrophysics Data System (ADS)

    Keawprasert, T.; Anhalt, K.; Taubert, D. R.; Sperling, A.; Schuster, M.; Nevas, S.

    2013-09-01

    An LP3 radiation thermometer was absolutely calibrated at a newly developed monochromator-based set-up and the TUneable Lasers in Photometry (TULIP) facility of PTB in the wavelength range from 400 nm to 1100 nm. At both facilities, the spectral radiation of the respective sources irradiates an integrating sphere, thus generating uniform radiance across its precision aperture. The spectral irradiance of the integrating sphere is determined via an effective area of a precision aperture and a Si trap detector, traceable to the primary cryogenic radiometer of PTB. Due to the limited output power from the monochromator, the absolute calibration was performed with the measurement uncertainty of 0.17 % (k = 1), while the respective uncertainty at the TULIP facility is 0.14 %. Calibration results obtained by the two facilities were compared in terms of spectral radiance responsivity, effective wavelength and integral responsivity. It was found that the measurement results in integral responsivity at the both facilities are in agreement within the expanded uncertainty (k = 2). To verify the calibration accuracy, the absolutely calibrated radiation thermometer was used to measure the thermodynamic freezing temperatures of the PTB gold fixed-point blackbody.

  9. Calibration of the Brookhaven National Laboratory delayed gamma neutron activation facility to measure total body calcium.

    PubMed

    Ma, R; Stamatelatos, I E; Yasumura, S

    2000-05-01

    Differences in body size and shape can cause large variances in the in vivo results of neutron activation analysis. To introduce corrections for body size for the delayed gamma neutron activation facility at Brookhaven National Laboratory, "reference man"-sized and "reference woman"-sized phantoms were constructed. Simulation results using the Monte Carlo Neutron and Photon Transport code also provided correction factors for people of different sizes. For individuals with a body mass index (BMI = weight (kg)/height (m)2) between 20 and 30, no correction was required. At BMIs greater than 30, the effects of neutron attenuation were significant and a correction factor of CF = -0.0192 x BMI + 1.5635 can be applied. PMID:10865727

  10. Sensitivity calibration of an imaging extreme ultraviolet spectrometer-detector system for determining the efficiency of broadband extreme ultraviolet sources

    SciTech Connect

    Fuchs, S.; Roedel, C.; Bierbach, J.; Paz, A. E.; Foerster, E.; Paulus, G. G.; Krebs, M.; Haedrich, S.; Limpert, J.; Kuschel, S.; Wuensche, M.; Hilbert, V.; Zastrau, U.

    2013-02-15

    We report on the absolute sensitivity calibration of an extreme ultraviolet (XUV) spectrometer system that is frequently employed to study emission from short-pulse laser experiments. The XUV spectrometer, consisting of a toroidal mirror and a transmission grating, was characterized at a synchrotron source in respect of the ratio of the detected to the incident photon flux at photon energies ranging from 15.5 eV to 99 eV. The absolute calibration allows the determination of the XUV photon number emitted by laser-based XUV sources, e.g., high-harmonic generation from plasma surfaces or in gaseous media. We have demonstrated high-harmonic generation in gases and plasma surfaces providing 2.3 {mu}W and {mu}J per harmonic using the respective generation mechanisms.

  11. VIEW OF BUILDING 126, LOOKING NORTH. BUILDING 126, THE SOURCE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF BUILDING 126, LOOKING NORTH. BUILDING 126, THE SOURCE CALIBRATION LABORATORY, WAS USED TO EXPOSE AND CALIBRATE RADIATION DETECTION DEVICES, INCLUDING THERMOLUMINESCENT DOSIMETERS, WORN BY EMPLOYEES TO DETECT RADIATION EXPOSURE - Rocky Flats Plant, Source Calibration Laboratory, Between Second & Third Streets & Central & Cedar Avenues, Golden, Jefferson County, CO

  12. [Laser-based radiometric calibration].

    PubMed

    Li, Zhi-gang; Zheng, Yu-quan

    2014-12-01

    Increasingly higher demands are put forward to spectral radiometric calibration accuracy and the development of new tunable laser based spectral radiometric calibration technology is promoted, along with the development of studies of terrestrial remote sensing, aeronautical and astronautical remote sensing, plasma physics, quantitative spectroscopy, etc. Internationally a number of national metrology scientific research institutes have built tunable laser based spectral radiometric calibration facilities in succession, which are traceable to cryogenic radiometers and have low uncertainties for spectral responsivity calibration and characterization of detectors and remote sensing instruments in the UK, the USA, Germany, etc. Among them, the facility for spectral irradiance and radiance responsivity calibrations using uniform sources (SIRCCUS) at the National Institute of Standards and Technology (NIST) in the USA and the Tunable Lasers in Photometry (TULIP) facility at the Physikalisch-Technische Bundesanstalt (PTB) in Germany have more representatives. Compared with lamp-monochromator systems, laser based spectral radiometric calibrations have many advantages, such as narrow spectral bandwidth, high wavelength accuracy, low calibration uncertainty and so on for radiometric calibration applications. In this paper, the development of laser-based spectral radiometric calibration and structures and performances of laser-based radiometric calibration facilities represented by the National Physical Laboratory (NPL) in the UK, NIST and PTB are presented, technical advantages of laser-based spectral radiometric calibration are analyzed, and applications of this technology are further discussed. Laser-based spectral radiometric calibration facilities can be widely used in important system-level radiometric calibration measurements with high accuracy, including radiance temperature, radiance and irradiance calibrations for space remote sensing instruments, and promote the

  13. [Laser-based radiometric calibration].

    PubMed

    Li, Zhi-gang; Zheng, Yu-quan

    2014-12-01

    Increasingly higher demands are put forward to spectral radiometric calibration accuracy and the development of new tunable laser based spectral radiometric calibration technology is promoted, along with the development of studies of terrestrial remote sensing, aeronautical and astronautical remote sensing, plasma physics, quantitative spectroscopy, etc. Internationally a number of national metrology scientific research institutes have built tunable laser based spectral radiometric calibration facilities in succession, which are traceable to cryogenic radiometers and have low uncertainties for spectral responsivity calibration and characterization of detectors and remote sensing instruments in the UK, the USA, Germany, etc. Among them, the facility for spectral irradiance and radiance responsivity calibrations using uniform sources (SIRCCUS) at the National Institute of Standards and Technology (NIST) in the USA and the Tunable Lasers in Photometry (TULIP) facility at the Physikalisch-Technische Bundesanstalt (PTB) in Germany have more representatives. Compared with lamp-monochromator systems, laser based spectral radiometric calibrations have many advantages, such as narrow spectral bandwidth, high wavelength accuracy, low calibration uncertainty and so on for radiometric calibration applications. In this paper, the development of laser-based spectral radiometric calibration and structures and performances of laser-based radiometric calibration facilities represented by the National Physical Laboratory (NPL) in the UK, NIST and PTB are presented, technical advantages of laser-based spectral radiometric calibration are analyzed, and applications of this technology are further discussed. Laser-based spectral radiometric calibration facilities can be widely used in important system-level radiometric calibration measurements with high accuracy, including radiance temperature, radiance and irradiance calibrations for space remote sensing instruments, and promote the

  14. Patient hydration: a major source of laboratory uncertainty.

    PubMed

    Ritchie, Robert F; Ledue, Thomas B; Craig, Wendy Y

    2007-01-01

    Movement of body water from compartment to compartment during any time period is attributable to forces active within and upon each space. The result of these forces leads to transfer of water between intravascular and extravascular compartments, as well as shifts between extracellular and intracellular spaces. The importance of these shifts and of the associated mechanism was described by Ernest Starling in 1896 in very much the same manner as it is viewed today. The end result of fluid transfer and its physiological and laboratory consequences has not been fully appreciated. Despite awareness that fluid shifts can affect laboratory analytical results, little recent investigation has addressed the problem in the routine clinical laboratory. Thus, the potential for significant misinterpretation remains. For example, it is known that individual laboratory test values can vary widely, depending on many factors including the subject's posture during and immediately before phlebotomy, leading to significant changes in the interpretation of blood analyte values. Furthermore, a variety of ubiquitous environmental effects have additional impact on fluid distribution and thus on test values. In other words, patient hydration status is a major pre-analytical variable that needs to be addressed by the clinical laboratory. The need to adjust data for patient hydration status is especially important in the case of colloid analytes for which the dynamic range includes a narrow "gray zone" where hydration changes of a few percentage points can change the clinical implications. The crucial importance of this adjustment is underscored by the fact that neither the testing laboratory nor the clinician are aware of this unseen circumstance and are thus compelled to work with data that do not necessarily reflect the clinical situation.

  15. CONSTRUCTION OF A CALIBRATED PROBABILISTIC CLASSIFICATION CATALOG: APPLICATION TO 50k VARIABLE SOURCES IN THE ALL-SKY AUTOMATED SURVEY

    SciTech Connect

    Richards, Joseph W.; Starr, Dan L.; Miller, Adam A.; Bloom, Joshua S.; Brink, Henrik; Crellin-Quick, Arien; Butler, Nathaniel R.

    2012-12-15

    With growing data volumes from synoptic surveys, astronomers necessarily must become more abstracted from the discovery and introspection processes. Given the scarcity of follow-up resources, there is a particularly sharp onus on the frameworks that replace these human roles to provide accurate and well-calibrated probabilistic classification catalogs. Such catalogs inform the subsequent follow-up, allowing consumers to optimize the selection of specific sources for further study and permitting rigorous treatment of classification purities and efficiencies for population studies. Here, we describe a process to produce a probabilistic classification catalog of variability with machine learning from a multi-epoch photometric survey. In addition to producing accurate classifications, we show how to estimate calibrated class probabilities and motivate the importance of probability calibration. We also introduce a methodology for feature-based anomaly detection, which allows discovery of objects in the survey that do not fit within the predefined class taxonomy. Finally, we apply these methods to sources observed by the All-Sky Automated Survey (ASAS), and release the Machine-learned ASAS Classification Catalog (MACC), a 28 class probabilistic classification catalog of 50,124 ASAS sources in the ASAS Catalog of Variable Stars. We estimate that MACC achieves a sub-20% classification error rate and demonstrate that the class posterior probabilities are reasonably calibrated. MACC classifications compare favorably to the classifications of several previous domain-specific ASAS papers and to the ASAS Catalog of Variable Stars, which had classified only 24% of those sources into one of 12 science classes.

  16. Construction of a Calibrated Probabilistic Classification Catalog: Application to 50k Variable Sources in the All-Sky Automated Survey

    NASA Astrophysics Data System (ADS)

    Richards, Joseph W.; Starr, Dan L.; Miller, Adam A.; Bloom, Joshua S.; Butler, Nathaniel R.; Brink, Henrik; Crellin-Quick, Arien

    2012-12-01

    With growing data volumes from synoptic surveys, astronomers necessarily must become more abstracted from the discovery and introspection processes. Given the scarcity of follow-up resources, there is a particularly sharp onus on the frameworks that replace these human roles to provide accurate and well-calibrated probabilistic classification catalogs. Such catalogs inform the subsequent follow-up, allowing consumers to optimize the selection of specific sources for further study and permitting rigorous treatment of classification purities and efficiencies for population studies. Here, we describe a process to produce a probabilistic classification catalog of variability with machine learning from a multi-epoch photometric survey. In addition to producing accurate classifications, we show how to estimate calibrated class probabilities and motivate the importance of probability calibration. We also introduce a methodology for feature-based anomaly detection, which allows discovery of objects in the survey that do not fit within the predefined class taxonomy. Finally, we apply these methods to sources observed by the All-Sky Automated Survey (ASAS), and release the Machine-learned ASAS Classification Catalog (MACC), a 28 class probabilistic classification catalog of 50,124 ASAS sources in the ASAS Catalog of Variable Stars. We estimate that MACC achieves a sub-20% classification error rate and demonstrate that the class posterior probabilities are reasonably calibrated. MACC classifications compare favorably to the classifications of several previous domain-specific ASAS papers and to the ASAS Catalog of Variable Stars, which had classified only 24% of those sources into one of 12 science classes.

  17. Hydro-mechanical constitutive model for unsaturated compacted bentonite-sand mixture (BSM): Laboratory tests, parameter calibrations, modifications, and applications

    NASA Astrophysics Data System (ADS)

    Priyanto, D. G.; Man, A. G.; Blatz, J. A.; Dixon, D. A.

    A bentonite-sand mixture (BSM) is one of the clay-based sealing components proposed for use in a Canadian deep geological repository (DGR) for used nuclear fuel. Numerical modelling to assess the overall design of the proposed DGR requires characterisation of the hydraulic-mechanical (H-M) of each of the components of the sealing system, including the BSM. The BSM currently under consideration is a 50/50 mixture (by dry mass) of bentonite and well-graded silica sand, compacted to a dry density of at least 1.67 Mg/m 3. This paper presents the H-M constitutive model parameters, calibrated for BSM specimens under saturated and unsaturated conditions, based on various laboratory tests. A set of parameters for an elastoplastic model for unsaturated soil, Basic Barcelona Model (BBM), have been determined to simulate the mechanical behaviour of the BSM specimen. A set of parameters for van Genuchten’s Soil-Water Characteristic Curve (SWCC) and Kozeny’s hydraulic permeability model have been determined to simulate the hydraulic behaviour of the BSM specimen. Using a finite element computer code, CODE_BRIGHT, these sets of parameters have been used to simulate H-M processes in BSM specimens during water infiltration under constant volume (CV) and constant mean stress (CMS) boundary conditions. The key features of the selected constitutive models that are different from the laboratory tests of the BSM specimen have been summarised. The functions to improve the capability of the selected constitutive models to match the laboratory test results of the BSM specimen have been proposed.

  18. Laboratory calibration of the seismo-acoustic response of CO2 saturated sandstones

    NASA Astrophysics Data System (ADS)

    Siggins, A. F.; Lwin, M.; Wisman, P.

    2009-04-01

    Geological sequestration can be regarded as one of the promising mitigation strategies against the negative effects of atmospheric carbon dioxide on global climate change. Injection of CO2into depleted natural gas reservoirs in particular, sandstone formations at depth with suitable porosity and seals, seems to be a promising scenario for on-land storage. In fact, a demonstration project is currently underway in the Otway Basin in South Eastern Australia under the auspices of the Australian CO2CRC. One of the most useful geophysical remote sensing tools for monitoring sub surface CO2 injection is seismic imaging. Interpretation of seismic data for the quantitative measurement of the distribution and saturations of CO2 in the subsurface requires a knowledge of the effects of CO2as a pore fluid on the seismo-acoustic response of the reservoir rocks. This report describes some recent experiments that we have conducted to investigate this aspect under controlled laboratory conditions at pressures representative of in-situ reservoir conditions. Prior to the availability of core from the actual Otway injection site, two synthetic sandstones were tested ultrasonically in a computer controlled triaxial testing rig under a range of confining pressures and pore pressures representative of in-situ reservoir pressures. These sandstones comprised; (1) a synthetic material with calcite intergranular cement (CIPS) and (2), a synthetic sandstone with silica intergranular cement. Porosities of the sandstones were respectively, 32%,and 33%. Initial testing was carried on the cores at room temperature-dried condition with confining pressures up to 65MPa in steps of 5 MPa. Cores were then flooded with CO2, initially at 6MPa, 22 degrees C, then with liquid phase CO2at pressures from 7MPa to 17 MPa in steps of 5 MPa. Confining pressures varied from 10 MPa to 65 MPa. A limited number of experiments were also conducted in an additional rig at 50oC with supercritical phase CO2. Ultrasonic

  19. Initial Radiometric Calibration of the AWiFS using Vicarious Calibration Techniques

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Thome, Kurtis; Aaron, David; Leigh, Larry

    2006-01-01

    NASA SSC maintains four ASD FieldSpec FR spectroradiometers: 1) Laboratory transfer radiometers; 2) Ground surface reflectance for V&V field collection activities. Radiometric Calibration consists of a NIST-calibrated integrating sphere which serves as a source with known spectral radiance. Spectral Calibration consists of a laser and pen lamp illumination of integrating sphere. Environmental Testing includes temperature stability tests performed in environmental chamber.

  20. A derivative standard for polarimeter calibration

    SciTech Connect

    Mulhollan, G.; Clendenin, J.; Saez, P.

    1996-10-01

    A long-standing problem in polarized electron physics is the lack of a traceable standard for calibrating electron spin polarimeters. While several polarimeters are absolutely calibrated to better than 2%, the typical instrument has an inherent accuracy no better than 10%. This variability among polarimeters makes it difficult to compare advances in polarized electron sources between laboratories. The authors have undertaken an effort to establish 100 nm thick molecular beam epitaxy grown GaAs(110) as a material which may be used as a derivative standard for calibrating systems possessing a solid state polarized electron source. The near-bandgap spin polarization of photoelectrons emitted from this material has been characterized for a variety of conditions and several laboratories which possess well calibrated polarimeters have measured the photoelectron polarization of cathodes cut from a common wafer. Despite instrumentation differences, the spread in the measurements is sufficiently small that this material may be used as a derivative calibration standard.

  1. Sandia National Laboratories' high power electromagnetic impulse sources

    NASA Astrophysics Data System (ADS)

    Rinehart, L. F.; Buttram, M. T.; Denison, G. J.; Lundstrom, J. M.; Crowe, W. R.; Aurand, J. F.; Patterson, P. E.

    1994-05-01

    Three impulse sources have been developed to cover a wide range of peak power, bandwidth and center frequency requirements. Each of the sources can operate in single shot, rep-rate, or burst modes. These devices are of rugged construction and are suitable for field use. This paper will describe the specifications and principals of operation for each source. The sources to be described are: SNIPER (Sub-Nanosecond ImPulsE Radiator), a coaxial Blumlein pulser with an in-line (series) peaking switch; EMBL (EnantioMorphic BLurfflein), a bipolar parallel plate Blumlein with a crowbar type (parallel) peaking switch; and the LCO (L-C Oscillator) a spark-switched L-C oscillator with damped sinusoidal output. SNIPER and EMBL are ultra-wideband (UWB) sources which produce a very fast high voltage transition. When differentiated by the antenna, an impulse whose width corresponds to the transition time is radiated. The LCO operates with a center frequency up to 800 MHz and up to 100 MHz bandwidth. Because the LCO output is relatively narrow band, high gain antennas may be employed to produce very high radiated field strengths.

  2. Sandia National Laboratories` high power electromagnetic impulse sources

    SciTech Connect

    Rinehart, L.F.; Buttram, M.T.; Denison, G.J.; Lundstrom, J.M.; Crowe, W.R.; Aurand, J.F.; Patterson, P.E.

    1994-10-01

    Three impulse sources have been developed to cover a wide range of peak power, bandwidth and center frequency requirements. Each of the sources can operate in single shot, rep-rate, or burst modes. These devices are of rugged construction and are suitable for field use. This paper will describe the specifications and principals of operation for each source. The sources to be described are: SNIPER (Sub-Nanosecond ImPulsE Radiator), a coaxial Blumlein pulser with an in-line (series) peaking switch; EMBL (EnantioMorphic BLurfflein), a bipolar parallel plate Blumlein with a crowbar type (parallel) peaking switch; and the LCO (L-C Oscillator) a spark-switched L-C oscillator with damped sinusoidal output. SNIPER and EMBL are ultra-wideband (UWB) sources which produce a very fast high voltage transition. When differentiated by the antenna, an impulse whose width corresponds to the transition time is radiated. The LCO operates with a center frequency up to 800 MHz and up to 100 MHz bandwidth. Because the LCO output is relatively narrow band, high gain antennas may be employed to produce very high radiated field strengths.

  3. Theoretic Studies of Full Constraints on a Star Tracker's Influential Error Sources for In-orbit Calibration

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Cai Hao, Yun; Wang, Li; Long, Ye

    2016-03-01

    To collect star transits data qualified for in-orbit calibration, this study derives the full error constraints to limit star tracker's influential error sources and computes their error boundaries from a theoretical perspective. The full constraints, including not only the minimum variance estimation of position but also the error bound prediction of scale and intensity of Gaussian-shaped starspots, are studied based on the Cramér-Rao Lower Bound (CRLB) theorem. By imposing these constraints on motion, drift in focal length, and other factors, their boundaries could be determined before launch. Therefore, the in-orbit correction accuracy is expected to be close to CRLB through suitable implementation of these constraints. The correctness of the theoretical position error of motion is demonstrated by the data-fitting procedure against test results of star tracker on dynamic performance. The simulation result shows that the drift in focal length can generate an error with the same magnitude as detector noise and thus might be the dominant error source when star tracker is working under stationary circumstance. Using the accuracy performance of some typical star trackers, this study shows that the CRLB constraint may be very effective to estimate the overall position error of a starspot or one axis, valuable data that can be used for online calibration. The overall position uncertainty analysis shows that a weighted method can be employed for calibration, a process where star data can be given a weight in inverse proportion to the CRLB value.

  4. Developing Biofuel in the Teaching Laboratory: Ethanol from Various Sources

    ERIC Educational Resources Information Center

    Epstein, Jessica L.; Vieira, Matthew; Aryal, Binod; Vera, Nicolas; Solis, Melissa

    2010-01-01

    In this series of experiments, we mimic a small-scale ethanol plant. Students discover that the practical aspects of ethanol production are determined by the quantity of biomass produced per unit land, rather than the volume of ethanol produced per unit of biomass. These experiments explore the production of ethanol from different sources: fruits,…

  5. PandASoft: Open Source Instructional Laboratory Administration Software

    NASA Astrophysics Data System (ADS)

    Gay, P. L.; Braasch, P.; Synkova, Y. N.

    2004-12-01

    PandASoft (Physics and Astronomy Software) is software for organizing and archiving a department's teaching resources and materials. An easy to use, secure interface allows faculty and staff to explore equipment inventories, see what laboratory experiments are available, find handouts, and track what has been used in different classes in the past. Divided into five sections: classes, equipment, laboratories, links, and media, its database cross links materials, allowing users to see what labs are used with which classes, what media and equipment are used with which labs, or simply what equipment is lurking in which room. Written in PHP and MySQL, this software can be installed on any UNIX / Linux platform, including Macintosh OS X. It is designed to allow users to easily customize the headers, footers and colors to blend with existing sites - no programming experience required. While initial data input is labor intensive, the system will save time later by allowing users to quickly answer questions related to what is in inventory, where it is located, how many are in stock, and where online they can learn more. It will also provide a central location for storing PDFs of handouts, and links to applets and cool sites at other universities. PandASoft comes with over 100 links to online resources pre-installed. We would like to thank Dr. Wolfgang Rueckner and the Harvard University Science Center for providing computers and resources for this project.

  6. WE-D-9A-06: Open Source Monitor Calibration and Quality Control Software for Enterprise Display Management

    SciTech Connect

    Bevins, N; Vanderhoek, M; Lang, S; Flynn, M

    2014-06-15

    Purpose: Medical display monitor calibration and quality control present challenges to medical physicists. The purpose of this work is to demonstrate and share experiences with an open source package that allows for both initial monitor setup and routine performance evaluation. Methods: A software package, pacsDisplay, has been developed over the last decade to aid in the calibration of all monitors within the radiology group in our health system. The software is used to calibrate monitors to follow the DICOM Grayscale Standard Display Function (GSDF) via lookup tables installed on the workstation. Additional functionality facilitates periodic evaluations of both primary and secondary medical monitors to ensure satisfactory performance. This software is installed on all radiology workstations, and can also be run as a stand-alone tool from a USB disk. Recently, a database has been developed to store and centralize the monitor performance data and to provide long-term trends for compliance with internal standards and various accrediting organizations. Results: Implementation and utilization of pacsDisplay has resulted in improved monitor performance across the health system. Monitor testing is now performed at regular intervals and the software is being used across multiple imaging modalities. Monitor performance characteristics such as maximum and minimum luminance, ambient luminance and illuminance, color tracking, and GSDF conformity are loaded into a centralized database for system performance comparisons. Compliance reports for organizations such as MQSA, ACR, and TJC are generated automatically and stored in the same database. Conclusion: An open source software solution has simplified and improved the standardization of displays within our health system. This work serves as an example method for calibrating and testing monitors within an enterprise health system.

  7. Calibration services for medical applications of radiation

    SciTech Connect

    DeWerd, L.A.

    1993-12-31

    Calibration services for the medical community applications of radiation involve measuring radiation precisely and having traceability to the National Institute of Standards and Technology (NIST). Radiation therapy applications involve the use of ionization chambers and electrometers for external beams and well-type ionization chamber systems as well as radioactive sources for brachytherapy. Diagnostic x-ray applications involve ionization chamber systems and devices to measure other parameters of the x-ray machine, such as non-invasive kVp meters. Calibration laboratories have been established to provide radiation calibration services while maintaining traceability to NIST. New radiation applications of the medical community spur investigation to provide the future calibration needs.

  8. Quality of determinations obtained from laboratory reference samples used in the calibration of X-ray electron probe microanalysis of silicate minerals

    NASA Astrophysics Data System (ADS)

    Pavlova, Ludmila A.; Suvorova, Ludmila F.; Belozerova, Olga Yu; Pavlov, Sergey M.

    2003-02-01

    Nine simple minerals and oxides, traditionally used as laboratory reference samples in the electron probe microanalysis (EPMA) of silicate minerals, have been quantitatively evaluated. Three separate series of data, comprising the average concentration, standard deviation, relative standard deviation, confidence interval and the z-score of data quality, were calculated for 21 control samples derived from calibrations obtained from three sets of reference samples: (1) simple minerals; (2) oxides; and (3) certified glass reference materials. No systematic difference was observed between the concentrations obtained from these three calibration sets when analyzed results were compared to certified compositions. The relative standard deviations obtained for each element were smaller than target values for all determinations. The z-score values for all elements determined fell within acceptable limits (-2< z<2) for concentrations ranging from 0.1 to 100%. These experiments show that the quality of data obtained from laboratory reference calibration samples is not inferior to that from certified reference glasses. The quality of results obtained corresponds to the 'applied geochemistry' type of analysis (category 2) as defined in the GeoPT proficiency testing program. Therefore, the laboratory reference samples can be used for calibrating EPMA techniques in the analysis of silicate minerals and for controlling the quality of results.

  9. Pre-flight calibration and initial data processing for the ChemCam laser-induced breakdown spectroscopy instrument on the Mars Science Laboratory rover

    USGS Publications Warehouse

    Wiens, R.C.; Maurice, S.; Lasue, J.; Forni, O.; Anderson, R.B.; Clegg, S.; Bender, S.; Blaney, D.; Barraclough, B.L.; Cousin, A.; DeFlores, L.; Delapp, D.; Dyar, M.D.; Fabre, C.; Gasnault, O.; Lanza, N.; Mazoyer, J.; Melikechi, N.; Meslin, P.-Y.; Newsom, H.; Ollila, A.; Perez, R.; Tokar, R.; Vaniman, D.

    2013-01-01

    The ChemCam instrument package on the Mars Science Laboratory rover, Curiosity, is the first planetary science instrument to employ laser-induced breakdown spectroscopy (LIBS) to determine the compositions of geological samples on another planet. Pre-processing of the spectra involves subtracting the ambient light background, removing noise, removing the electron continuum, calibrating for the wavelength, correcting for the variable distance to the target, and applying a wavelength-dependent correction for the instrument response. Further processing of the data uses multivariate and univariate comparisons with a LIBS spectral library developed prior to launch as well as comparisons with several on-board standards post-landing. The level-2 data products include semi-quantitative abundances derived from partial least squares regression. A LIBS spectral library was developed using 69 rock standards in the form of pressed powder disks, glasses, and ceramics to minimize heterogeneity on the scale of the observation (350–550 μm dia.). The standards covered typical compositional ranges of igneous materials and also included sulfates, carbonates, and phyllosilicates. The provenance and elemental and mineralogical compositions of these standards are described. Spectral characteristics of this data set are presented, including the size distribution and integrated irradiances of the plasmas, and a proxy for plasma temperature as a function of distance from the instrument. Two laboratory-based clones of ChemCam reside in Los Alamos and Toulouse for the purpose of adding new spectra to the database as the need arises. Sensitivity to differences in wavelength correlation to spectral channels and spectral resolution has been investigated, indicating that spectral registration needs to be within half a pixel and resolution needs to match within 1.5 to 2.6 pixels. Absolute errors are tabulated for derived compositions of each major element in each standard using PLS regression

  10. Calibration of second-order correlation functions for nonstationary sources with a multistart, multistop time-to-digital converter

    SciTech Connect

    Choi, Wonshik; Lee, Moonjoo; Lee, Ye-Ryoung; Park, Changsoon; Lee, Jai-Hyung; An, Kyungwon; Fang-Yen, C.; Dasari, R. R.; Feld, M. S.

    2005-08-15

    A novel high-throughput second-order correlation measurement system is developed that records and makes use of all the arrival times of photons detected at both start and stop detectors. This system is suitable, particularly for a light source having a high photon flux and a long coherence time, since it is more efficient than conventional methods by an amount equal to the product of the count rate and the correlation time of the light source. We have used this system in carefully investigating the dead time effects of detectors and photon counters on the second-order correlation function in the two-detector configuration. For a nonstationary light source, a distortion of the original signal was observed at high photon flux. A systematic way of calibrating the second-order correlation function has been devised by introducing the concept of an effective dead time of the entire measurement system.

  11. ENHANCED BIOREMEDIATION UTILIZING HYDROGEN PEROXIDE AS A SUPPLEMENTAL SOURCE OF OXYGEN: A LABORATORY AND FIELD STUDY

    EPA Science Inventory

    Laboratory and field scale studies were conducted to investigate the feasibility of using hydrogen peroxide as a supplemental source of oxygen for bioremediation of an aviation gasoline fuel spill. Field samples of aviation gasoline contaminated aquifer material were artificially...

  12. Francium sources at Laboratori Nazionali di Legnaro: Design and performance

    SciTech Connect

    Stancari, G.; Veronesi, S.; Corradi, L.; Atutov, S.N.; Calabrese, R.; Dainelli, A.; Mariotti, E.; Moi, L.; Sanguinetti, S.; Tomassetti, L.

    2006-03-15

    A facility for the production of radioactive francium is operating at the laboratories of the Istituto Nazionale di Fisica Nucleare (INFN) in Legnaro, Italy. The goal is to collect a cold sample of radioactive atoms in a magneto-optical trap for studies in atomic, nuclear, and particle physics. Production of francium is achieved via the fusion-evaporation reaction {sup 197}Au({sup 18}O,kn){sup 215-k}Fr generated by a {approx}100-MeV {sup 18}O{sup 6+} beam on a thick gold target. The production target is heated to {approx}1200 K and kept at a potential of +3 kV to enhance Fr diffusion and surface desorption. Average production rates are 0.7x10{sup 6} ions/s for {sup 210}Fr with a primary beam flux of 10{sup 12} particles/s, with peaks of 2x10{sup 6} ions/s. Details are given on the design and construction of the production targets and on the measurements that characterize their performance.

  13. Francium sources at Laboratori Nazionali di Legnaro: Design and performance

    NASA Astrophysics Data System (ADS)

    Stancari, G.; Veronesi, S.; Corradi, L.; Atutov, S. N.; Calabrese, R.; Dainelli, A.; Mariotti, E.; Moi, L.; Sanguinetti, S.; Tomassetti, L.

    2006-03-01

    A facility for the production of radioactive francium is operating at the laboratories of the Istituto Nazionale di Fisica Nucleare (INFN) in Legnaro, Italy. The goal is to collect a cold sample of radioactive atoms in a magneto-optical trap for studies in atomic, nuclear, and particle physics. Production of francium is achieved via the fusion-evaporation reaction Au197(O18,kn)215-kFr generated by a ˜100-MeV O6+18 beam on a thick gold target. The production target is heated to ˜1200K and kept at a potential of +3kV to enhance Fr diffusion and surface desorption. Average production rates are 0.7×106ions/s for Fr210 with a primary beam flux of 1012particles/s, with peaks of 2×106ions/s. Details are given on the design and construction of the production targets and on the measurements that characterize their performance.

  14. Laboratory Reproduction of Auroral Magnetospheric Radio Wave Sources

    SciTech Connect

    Ronald, K.; Speirs, D. C.; McConville, S. L.; Gillespie, K. M.; Phelps, A. D. R.; Cross, A. W.; Robertson, C. W.; Whyte, C. G.; He, W.; Bingham, R.; Vorgul, I.; Cairns, R. A.; Kellett, B. J.

    2008-10-15

    Auroral Kilometric Radiation, AKR, occurs naturally in the polar regions of the Earth's magnetosphere where electrons are accelerated by electric fields into the increasing planetary magnetic dipole. Here conservation of the magnetic moment converts axial to rotational momentum forming a horseshoe distribution in velocity phase space. This distribution is unstable to cyclotron emissions and radiation is emitted in the X-mode. In the laboratory a 75-85kV electron beam of 5-40A was magnetically compressed by a system of solenoids. Results are presented for an electron beam gyrating at cyclotron frequencies of 4.42GHz and 11.7GHz resonating with near cut-off TE01 and TE03 modes respectively. Measurements of the electron transport combined with numerical simulations demonstrated that a horseshoe distribution function was formed in electron velocity space. Analysis of the experimental measurements allowed the inference of the 1D number density as a function of the electron beam pitch angle. The total power emitted experimentally was {approx}19-35 kW with a maximum RF emission efficiency of {approx}2%. These results were compared to those obtained numerically using a 2D PiC code KARAT with a maximum efficiency of 2% predicted for the same mode and frequency, consistent with astrophysical and theoretical results.

  15. 226Ra as a standard source for efficiency calibration of Ge(Li) detectors

    NASA Astrophysics Data System (ADS)

    Farouk, M. A.; Al-Soraya, A. M.

    1982-09-01

    The relative intensities of gamma-rays resulting from the decay of 226Ra in equilibrium with its short-lived daughters have been measured using two different high resolution Ge(Li) detectors. The accuracy of the measurements does not exceed 2.5%. The most intense components of gamma-rays from thin 226Ra are recommended for use as a calibration standard Ge(Li) detectors in the energy range from 186 keV to 3.050 MeV.

  16. Environmental calibration chamber operations

    NASA Technical Reports Server (NTRS)

    Lester, D. L.

    1988-01-01

    Thermal vacuum capabilities are provided for the development, calibration, and functional operation checks of flight sensors, sources, and laboratory and field instruments. Two systems are available. The first is a 46 cm diameter diffusion pumped vacuum chambler of the bell jar variety. It has an internal thermal shroud, LN2 old trap, two viewing ports, and various electrical and fluid feedthroughs. The other, also an oil diffusion pumped system, consists of a 1.8 m diameter by 2.5 m long stainless steel vacuum tank, associated pumping and control equipment, a liquid nitrogen storage and transfer system and internal IR/visible calibration sources. This is a two story system with the chamber located on one floor and the pumping/cryogenic systems located on the floor below.

  17. Radiative transfer modeling of dust-coated Pancam calibration target materials: Laboratory visible/near-infrared spectrogoniometry

    USGS Publications Warehouse

    Johnson, J. R.; Sohl-Dickstein, J.; Grundy, W.M.; Arvidson, R. E.; Bell, J.F.; Christensen, P.R.; Graff, T.; Guinness, E.A.; Kinch, K.; Morris, R.; Shepard, M.K.

    2006-01-01

    Laboratory visible/near-infrared multispectral observations of Mars Exploration Rover Pancam calibration target materials coated with different thicknesses of Mars spectral analog dust were acquired under variable illumination geometries using the Bloomsburg University Goniometer. The data were fit with a two-layer radiative transfer model that combines a Hapke formulation for the dust with measured values of the substrate interpolated using a He-Torrance approach. We first determined the single-scattering albedo, phase function, opposition effect width, and amplitude for the dust using the entire data set (six coating thicknesses, three substrates, four wavelengths, and phase angles 3??-117??). The dust exhibited single-scattering albedo values similar to other Mars analog soils and to Mars Pathfinder dust and a dominantly forward scattering behavior whose scattering lobe became narrower at longer wavelengths. Opacity values for each dust thickness corresponded well to those predicted from the particles sizes of the Mars analog dust. We then restricted the number of substrates, dust thicknesses, and incidence angles input to the model. The results suggest that the dust properties are best characterized when using substrates whose reflectances are brighter and darker than those of the deposited dust and data that span a wide range of dust thicknesses. The model also determined the dust photometric properties relatively well despite limitations placed on the range of incidence angles. The model presented here will help determine the photometric properties of dust deposited on the MER rovers and to track the multiple episodes of dust deposition and erosion that have occurred at both landing sites. Copyright 2006 by the American Geophysical Union.

  18. Quantifying amine permeation sources with acid neutralization: calibrations and amines measured in coastal and continental atmospheres

    NASA Astrophysics Data System (ADS)

    Freshour, N. A.; Carlson, K. K.; Melka, Y. A.; Hinz, S.; Panta, B.; Hanson, D. R.

    2014-04-01

    An acid titration method for quantifying amine permeation rates was used to calibrate an Ambient pressure Proton transfer Mass Spectrometer (AmPMS) that monitors ambient amine compounds. The method involves capturing amines entrained in a N2 flow by bubbling it through an acidified solution (~ 10-5 M HCl), and the amines are quantified via changes in solution pH with time. Home-made permeation tubes had permeation rates (typically tens of pmol s-1) that depended on the type of amine and tubing and on temperature. Calibrations of AmPMS yielded sensitivities for ammonia, methyl amine, dimethyl amine, and trimethyl amine that are close to the sensitivity assuming a gas-kinetic, ion-molecule rate coefficient. The permeation tubes were also designed to deliver a reproducible amount of amine to a flow reactor where nucleation with sulfuric acid was studied. The high proton affinity compound dimethyl sulfoxide (DMSO), linked to oceanic environments, was also studied and AmPMS is highly sensitive to it. AmPMS was deployed recently in two field campaigns and mixing ratios are reported for ammonia, alkyl amines, and DMSO and correlations between these species and with particle formation events are discussed.

  19. Ophthalmic applicators: An overview of calibrations following the change to SI units

    SciTech Connect

    Holmes, Shannon M.; Micka, John A.; DeWerd, Larry A.

    2009-05-15

    Since the NIST dose to water standard for {sup 90}Sr/{sup 90}Y ophthalmic applicators was introduced, numerous sources have undergone calibration either at NIST or at the University of Wisconsin Accredited Dosimetry Calibration Laboratory (UWADCL). From 1997 to 2008, 222 of these beta-emitting sources were calibrated at the UWADCL, and prior reference source strength values were available for 149 of these sources. A survey of UWADCL ophthalmic applicator calibrations is presented here, demonstrating an average discrepancy of -19% with a standard deviation of {+-}16% between prior reference values and the NIST-traceable UWADCL absorbed dose to water calibrations. Values ranged from -49% to +42%.

  20. Improvement in the practical implementation of neutron source strength calibration using prompt gamma rays.

    PubMed

    Khabaz, Rahim; Rene Vega-Carrillo, Hector

    2013-08-01

    In this study, the neutron emission rate from neutron sources using prompt gamma rays in hydrogen was determined, and several improvements were applied. Using Monte Carlo calculations, the best positions for the source, moderator and detector relative to each other were selected. For (241)Am-Be and (252)Cf sources, the sizes for polyethylene spheres with the highest efficiency were 12- and 10-inch, respectively. In addition, a new shielding cone was designed to account for scattered neutrons and gamma rays. The newly designed shielding cone, which is 45 cm in length, provided suitable attenuation for the source radiation.

  1. High-resolution continuum source electrothermal atomic absorption spectrometry: Linearization of the calibration curves within a broad concentration range

    NASA Astrophysics Data System (ADS)

    Katskov, Dmitri; Hlongwane, Miranda; Heitmann, Uwe; Florek, Stefan

    2012-05-01

    The calculation algorithm suggested provides linearization of the calibration curves in high-resolution continuum source electrothermal atomic absorption spectrometry. The algorithm is based on the modification of the function wavelength-integrated absorbance vs. concentration of analyte vapor in the absorption volume. According to the suggested approach, the absorption line is represented by a triangle for low and trapezium for high analyte vapor concentration in the absorption volume. The respective semi-empirical formulas include two linearization parameters, which depend on properties of the absorption line and characteristics of the atomizer and spectrometer. The parameters can be approximately evaluated from the theory and determined in practice from the original broad-range calibration curve. The parameters were found and the proposed calculation algorithm verified in the experiments on direct determination of Ag, Cd, Cu, Fe, Mn and Pb in the solutions within a concentration ranges from 0.15 to 625 μg·L- 1 using tube, platform tube and filter furnace atomizers. The use of various atomizers, lines, elements and atomization temperatures made possible the simulation of various practical analytical conditions. It was found that the algorithm and optimal linearization parameters made it possible to obtain for each line and atomizer linear approximations of the calibration curves within 3-4 orders of magnitude with correlation coefficients close to 0.999. The algorithm makes possible to employ a single line for the direct element determination over a broad concentration range. The sources of errors and the possibility of a priori theoretical evaluation of the linearization parameters are discussed.

  2. Calibration of a wide-field frequency-domain fluorescence lifetime microscopy system using light emitting diodes as light sources.

    PubMed

    Elder, A D; Frank, J H; Swartling, J; Dai, X; Kaminski, C F

    2006-11-01

    High brightness light emitting diodes are an inexpensive and versatile light source for wide-field frequency-domain fluorescence lifetime imaging microscopy. In this paper a full calibration of an LED based fluorescence lifetime imaging microscopy system is presented for the first time. A radio-frequency generator was used for simultaneous modulation of light emitting diode (LED) intensity and the gain of an intensified charge coupled device (CCD) camera. A homodyne detection scheme was employed to measure the demodulation and phase shift of the emitted fluorescence, from which phase and modulation lifetimes were determined at each image pixel. The system was characterized both in terms of its sensitivity to measure short lifetimes (500 ps to 4 ns), and its capability to distinguish image features with small lifetime differences. Calibration measurements were performed in quenched solutions containing Rhodamine 6G dye and the results compared to several independent measurements performed with other measurement methodologies, including time correlated single photon counting, time gated detection, and acousto optical modulator (AOM) based modulation of excitation sources. Results are presented from measurements and simulations. The effects of limited signal-to-noise ratios, baseline drifts and calibration errors are discussed in detail. The implications of limited modulation bandwidth of high brightness, large area LED devices ( approximately 40 MHz for devices used here) are presented. The results show that phase lifetime measurements are robust down to sub ns levels, whereas modulation lifetimes are prone to errors even at large signal-to-noise ratios. Strategies for optimizing measurement fidelity are discussed. Application of the fluorescence lifetime imaging microscopy system is illustrated with examples from studies of molecular mixing in microfluidic devices and targeted drug delivery research. PMID:17204064

  3. Calibration of the KRISS reference ionization chamber for certification of ²²²Rn gaseous sources.

    PubMed

    Lee, J M; Lee, K B; Lee, S H; Oh, P J; Park, T S; Kim, B C; Lee, M S

    2013-11-01

    A primary measurement system for gaseous (222)Rn based on the defined solid angle counting method has recently been constructed at KRISS and the reference ionization chamber used to measure the activities of gamma-emitting single radionuclides was adopted as a secondary standard for gaseous (222)Rn. A 20 mL flame-sealed glass ampoule source from the primary measurement system was used to calibrate the ionization chamber for (222)Rn. The (222)Rn efficiency of the ionization chamber was compared with that calculated by using a photon energy-dependent efficiency curve and that measured by using a standard (226)Ra solution. From the comparisons we draw the conclusion that the reference ionization chamber for gamma-emitting radionuclides can be a suitable secondary measurement system for gaseous (222)Rn sources.

  4. Implementation of 188-element curvature-based wavefront sensor and calibration source unit for the Subaru LGSAO system

    NASA Astrophysics Data System (ADS)

    Watanabe, Makoto; Oya, Shin; Hayano, Yutaka; Takami, Hideki; Hattori, Masayuki; Minowa, Yosuke; Saito, Yoshihiko; Ito, Meguru; Murakami, Naoshi; Iye, Masanori; Guyon, Olivier; Colley, Stephen; Eldred, Michael; Golota, Taras; Dinkins, Matthew

    2008-07-01

    The Subaru laser guide star adaptive optics (AO) system was installed at the Nasmyth focus of the Subaru Telescope, and had the first light with natural guide star on October 2006. The AO system has a 188-element curvature based wavefront sensor with photon-counting avalanche photodiode (APD) modules. It measures high-order terms of wavefront using either of a single laser (LGS) or natural guide star (NGS) within a 2' diameter field. The AO system has also a source simulator. It simulates LGS and NGS beams, simultaneously, with and without atmospheric turbulence by two turbulent layer at about 0 and 6 km altitudes, and reproduces the cone effect for the LGS beam. We describe the design, construction, and integration of the curvature wavefront sensor and calibration source unit.

  5. 10 CFR 35.65 - Authorization for calibration, transmission, and reference sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) Sealed sources, not exceeding 1.11 GBq (30 mCi) each, manufactured and distributed by a person licensed... exceeding 1.11 GBq (30 mCi) each, redistributed by a licensee authorized to redistribute the sealed sources... longer than 120 days in individual amounts not to exceed 0.56 GBq (15 mCi). (d) Any byproduct...

  6. Using cross correlations to calibrate lensing source redshift distributions: Improving cosmological constraints from upcoming weak lensing surveys

    SciTech Connect

    De Putter, Roland; Doré, Olivier; Das, Sudeep

    2014-01-10

    Cross correlations between the galaxy number density in a lensing source sample and that in an overlapping spectroscopic sample can in principle be used to calibrate the lensing source redshift distribution. In this paper, we study in detail to what extent this cross-correlation method can mitigate the loss of cosmological information in upcoming weak lensing surveys (combined with a cosmic microwave background prior) due to lack of knowledge of the source distribution. We consider a scenario where photometric redshifts are available and find that, unless the photometric redshift distribution p(z {sub ph}|z) is calibrated very accurately a priori (bias and scatter known to ∼0.002 for, e.g., EUCLID), the additional constraint on p(z {sub ph}|z) from the cross-correlation technique to a large extent restores the cosmological information originally lost due to the uncertainty in dn/dz(z). Considering only the gain in photo-z accuracy and not the additional cosmological information, enhancements of the dark energy figure of merit of up to a factor of four (40) can be achieved for a SuMIRe-like (EUCLID-like) combination of lensing and redshift surveys, where SuMIRe stands for Subaru Measurement of Images and Redshifts). However, the success of the method is strongly sensitive to our knowledge of the galaxy bias evolution in the source sample and we find that a percent level bias prior is needed to optimize the gains from the cross-correlation method (i.e., to approach the cosmology constraints attainable if the bias was known exactly).

  7. Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). A description of the sensor, ground data processing facility, laboratory calibration, and first results

    NASA Technical Reports Server (NTRS)

    Vane, Gregg (Editor)

    1987-01-01

    The papers in this document were presented at the Imaging Spectroscopy 2 Conference of the 31st International Symposium on Optical and Optoelectronic Applied Science and Engineering, in San Diego, California, on 20 and 21 August 1987. They describe the design and performance of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) sensor and its subsystems, the ground data processing facility, laboratory calibration, and first results.

  8. Fiber optic microphone having a pressure sensing reflective membrane and a voltage source for calibration purpose

    NASA Technical Reports Server (NTRS)

    Zuckerwar, Allan J. (Inventor); Cuomo, Frank W. (Inventor); Robbins, William E. (Inventor)

    1993-01-01

    A fiber optic microphone is provided for measuring fluctuating pressures. An optical fiber probe having at least one transmitting fiber for transmitting light to a pressure-sensing membrane and at least one receiving fiber for receiving light reflected from a stretched membrane is provided. The pressure-sensing membrane may be stretched for high frequency response. Further, a reflecting surface of the pressure-sensing membrane may have dimensions which substantially correspond to dimensions of a cross section of the optical fiber probe. Further, the fiber optic microphone can be made of materials for use in high temperature environments, for example greater than 1000 F. A fiber optic probe is also provided with a back plate for damping membrane motion. The back plate further provides a means for on-line calibration of the microphone.

  9. Comparison of Continuous-Wave CO2 Lidar Calibration by use of Earth-Surface Targets in Laboratory and Airborne Measurements

    NASA Technical Reports Server (NTRS)

    Jarzembski, Maurice A.; Srivastava, Vandana

    1998-01-01

    Backscatter of several Earth surfaces was characterized in the laboratory as a function of incidence angle with a focused continuous-wave 9.1 micro meter CO2 Doppler lidar for use as possible calibration targets. Some targets showed negligible angular dependence, while others showed a slight increase with decreasing angle. The Earth-surface signal measured over the complex Californian terrain during a 1995 NASA airborne mission compared well with laboratory data. Distributions of the Earth's surface signal shows that the lidar efficiency can be estimated with a fair degree of accuracy, preferably with uniform Earth-surface targets during flight for airborne or space-based lidar.

  10. The Source-lens Clustering Effect in the Context of Lensing Tomography and Its Self-calibration

    NASA Astrophysics Data System (ADS)

    Yu, Yu; Zhang, Pengjie; Lin, Weipeng; Cui, Weiguang

    2015-04-01

    Cosmic shear can only be measured where there are galaxies. This source-lens clustering (SLC) effect has two sources, intrinsic source clustering and cosmic magnification (magnification/size bias). Lensing tomography can suppress the former. However, this reduction is limited by the existence of photo-z error and nonzero redshift bin width. Furthermore, SLC induced by cosmic magnification cannot be reduced by lensing tomography. Through N-body simulations, we quantify the impact of SLC on the lensing power spectrum in the context of lensing tomography. We consider both the standard estimator and the pixel-based estimator. We find that none of them can satisfactorily handle both sources of SLC. (1) For the standard estimator, SLC induced by both sources can bias the lensing power spectrum by O≤ft( 1 \\right)-O(10)%. Intrinsic source clustering also increases statistical uncertainties in the measured lensing power spectrum. However, the standard estimator suppresses intrinsic source clustering in the cross-spectrum. (2) In contrast, the pixel-based estimator suppresses SLC through cosmic magnification. However, it fails to suppress SLC through intrinsic source clustering and the measured lensing power spectrum can be biased low by O≤ft( 1 \\right)-O(10)%. In short, for typical photo-z errors ({σ }z}/≤ft( 1+z \\right)=0.05) and photo-z bin sizes ({Δ{{z}P}=0.2), SLC alters the lensing E-mode power spectrum by 1-10%, with \\ell ˜ {{10}3} and {{z}s}˜ 1 being of particular interest to weak lensing cosmology. Therefore the SLC is a severe systematic for cosmology in Stage-IV lensing surveys. We present useful scaling relations to self-calibrate the SLC effect.

  11. PLACE: an open-source python package for laboratory automation, control, and experimentation.

    PubMed

    Johnson, Jami L; Tom Wörden, Henrik; van Wijk, Kasper

    2015-02-01

    In modern laboratories, software can drive the full experimental process from data acquisition to storage, processing, and analysis. The automation of laboratory data acquisition is an important consideration for every laboratory. When implementing a laboratory automation scheme, important parameters include its reliability, time to implement, adaptability, and compatibility with software used at other stages of experimentation. In this article, we present an open-source, flexible, and extensible Python package for Laboratory Automation, Control, and Experimentation (PLACE). The package uses modular organization and clear design principles; therefore, it can be easily customized or expanded to meet the needs of diverse laboratories. We discuss the organization of PLACE, data-handling considerations, and then present an example using PLACE for laser-ultrasound experiments. Finally, we demonstrate the seamless transition to post-processing and analysis with Python through the development of an analysis module for data produced by PLACE automation.

  12. The LBA Calibrator Survey of Southern Compact Extragalactic Radio Sources - LCS1

    NASA Technical Reports Server (NTRS)

    Petrov, Leonid; Phillips, Chris; Bertarini, Alessandra; Murphy, Tara; Sadler, Elaine M.

    2011-01-01

    We present a catalogue of accurate positions and correlated flux densities for 410 flat-spectrum, compact extragalactic radio sources previously detected in the Australia Telescope 20 GHz (AT20G) survey. The catalogue spans the declination range [-90deg, -40deg] and was constructed from four 24-h very long baseline interferometry (VLBI) observing sessions with the Australian Long Baseline Array at 8.3 GHz. The VLBI detection rate in these experiments is 97 per cent, the median uncertainty of the source positions is 2.6 mas and the median correlated flux density on projected baselines longer than 1000 km is 0.14 Jy. The goals of this work are (1) to provide a pool of southern sources with positions accurate to a few milliarcsec, which can be used for phase-referencing observations, geodetic VLBI and space navigation; (2) to extend the complete flux-limited sample of compact extragalactic sources to the Southern hemisphere; and (3) to investigate the parsec-scale properties of high-frequency selected sources from the AT20G survey. As a result of this VLBI campaign, the number of compact radio sources south of declination -40deg which have measured VLBI correlated flux densities and positions known to milliarcsec accuracy has increased by a factor of 3.5.

  13. Spectrally and Radiometrically Stable Wide-Band on Board Calibration Source for In-Flight Data Validation in Imaging Spectroscopy Applications

    NASA Technical Reports Server (NTRS)

    Coles, J. B.; Richardson, Brandon S.; Eastwood, Michael L.; Sarture, Charles M.; Quetin, Gregory R.; Hernandez, Marco A.; Kroll, Linley A.; Nolte, Scott H.; Porter, Michael D.; Green, Robert O.

    2011-01-01

    The quality of the quantitative spectral data collected by an imaging spectrometer instrument is critically dependent upon the accuracy of the spectral and radiometric calibration of the system. In order for the collected spectra to be scientifically useful, the calibration of the instrument must be precisely known not only prior to but during data collection. Thus, in addition to a rigorous in-lab calibration procedure, the airborne instruments designed and built by the NASA/JPL Imaging Spectroscopy Group incorporate an on board calibrator (OBC) system with the instrument to provide auxiliary in-use system calibration data. The output of the OBC source illuminates a target panel on the backside of the foreoptics shutter both before and after data collection. The OBC and in-lab calibration data sets are then used to validate and post-process the collected spectral image data. The resulting accuracy of the spectrometer output data is therefore integrally dependent upon the stability of the OBC source. In this paper we describe the design and application of the latest iteration of this novel device developed at NASA/JPL which integrates a halogen-cycle source with a precisely designed fiber coupling system and a fiber-based intensity monitoring feedback loop. The OBC source in this Airborne Testbed Spectrometer was run over a period of 15 hours while both the radiometric and spectral stabilities of the output were measured and demonstrated stability to within 1% of nominal.

  14. Practical biosafety in the tuberculosis laboratory: containment at the source is what truly counts.

    PubMed

    van Soolingen, D; Wisselink, H J; Lumb, R; Anthony, R; van der Zanden, A; Gilpin, C

    2014-08-01

    In industrialised countries, sufficient resources for establishing and maintaining fully equipped biosafety level 3 (BSL-3) laboratories according to international standards are generally available. BSL-3 laboratories are designed to provide several layers of containment to protect the laboratory worker as well as the outside environment and community from risk of exposure in case of local contamination. However, such facilities are scarce in high-burden settings, primarily due to the high financial burden and complexity of the initial construction and/or regular maintenance. Measures to prevent unintended exposure to Mycobacterium tuberculosis during laboratory manipulation of specimens and cultures is the first, and by far the most important, aspect of containment. This paper focuses on the need for risk containment at source. Assuming that in many settings the establishment of BSL-3 laboratories with all the required features is not achievable, this paper also discusses the minimum requirements necessary to mitigate risks associated with particular laboratory procedures. The term 'TB containment laboratory' is used throughout this paper to describe the minimum requirements for a laboratory suitable for high-risk procedures. The TB containment laboratory has many, but not all, of the features of a BSL-3 laboratory. PMID:25199000

  15. Practical biosafety in the tuberculosis laboratory: containment at the source is what truly counts.

    PubMed

    van Soolingen, D; Wisselink, H J; Lumb, R; Anthony, R; van der Zanden, A; Gilpin, C

    2014-08-01

    In industrialised countries, sufficient resources for establishing and maintaining fully equipped biosafety level 3 (BSL-3) laboratories according to international standards are generally available. BSL-3 laboratories are designed to provide several layers of containment to protect the laboratory worker as well as the outside environment and community from risk of exposure in case of local contamination. However, such facilities are scarce in high-burden settings, primarily due to the high financial burden and complexity of the initial construction and/or regular maintenance. Measures to prevent unintended exposure to Mycobacterium tuberculosis during laboratory manipulation of specimens and cultures is the first, and by far the most important, aspect of containment. This paper focuses on the need for risk containment at source. Assuming that in many settings the establishment of BSL-3 laboratories with all the required features is not achievable, this paper also discusses the minimum requirements necessary to mitigate risks associated with particular laboratory procedures. The term 'TB containment laboratory' is used throughout this paper to describe the minimum requirements for a laboratory suitable for high-risk procedures. The TB containment laboratory has many, but not all, of the features of a BSL-3 laboratory.

  16. Low-level measuring techniques for neutrons: High accuracy neutron source strength determination and fluence rate measurement at an underground laboratory

    SciTech Connect

    Zimbal, Andreas; Reginatto, Marcel; Schuhmacher, Helmut; Wiegel, Burkhard; Degering, Detlev; Zuber, Kai

    2013-08-08

    We report on measuring techniques for neutrons that have been developed at the Physikalisch-Technische Bundesanstalt (PTB), the German National Metrology Institute. PTB has characterized radioactive sources used in the BOREXINO and XENON100 experiments. For the BOREXINO experiment, a {sup 228}Th gamma radiation source was required which would not emit more than 10 neutrons per second. The determination of the neutron emission rate of this specially designed {sup 228}Th source was challenging due to the low neutron emission rate and because the ratio of neutron to gamma radiation was expected to be extremely low, of the order of 10{sup −6}. For the XENON100 detector, PTB carried out a high accuracy measurement of the neutron emission rate of an AmBe source. PTB has also done measurements in underground laboratories. A two month measurement campaign with a set of {sup 3}He-filled proportional counters was carried out in PTB's former UDO underground laboratory at the Asse salt mine. The aim of the campaign was to determine the intrinsic background of detectors, which is needed for the analysis of data taken in lowintensity neutron fields. At a later time, PTB did a preliminary measurement of the neutron fluence rate at the underground laboratory Felsenkeller operated by VKTA. By taking into account data from UDO, Felsenkeller, and detector calibrations made at the PTB facility, it was possible to estimate the neutron fluence rate at the Felsenkeller underground laboratory.

  17. In situ calibration of a light source in a sensor device

    DOEpatents

    Okandan, Murat; Serkland, Darwin k.; Merchant, Bion J.

    2015-12-29

    A sensor device is described herein, wherein the sensor device includes an optical measurement system, such as an interferometer. The sensor device further includes a low-power light source that is configured to emit an optical signal having a constant wavelength, wherein accuracy of a measurement output by the sensor device is dependent upon the optical signal having the constant wavelength. At least a portion of the optical signal is directed to a vapor cell, the vapor cell including an atomic species that absorbs light having the constant wavelength. A photodetector captures light that exits the vapor cell, and generates an electrical signal that is indicative of intensity of the light that exits the vapor cell. A control circuit controls operation of the light source based upon the electrical signal, such that the light source emits the optical signal with the constant wavelength.

  18. Thermal infrared radiometer calibration and experimental measurements

    NASA Astrophysics Data System (ADS)

    Wei, JiAn; Wang, Difeng; Gong, Fang; Yan, Bai; He, Xianqiang

    2015-08-01

    Thermal infrared radiometers play a vital role in obtaining information in field measurements and also in verifying information from remote sensing satellite sensor data. However, the calibration precision of the thermal infrared radiometers directly affects the accuracy of the remote sensing data analysis and application. It is therefore necessary to ensure that the calibration of thermal infrared radiometers is of sufficient and reliable precision. In this paper, the theory of a six-band thermal infrared radiometer (CE 312-2 ASTER) calibration method was introduced, with the calibration being conducted by using a blackbody source in the laboratory. The sources of error during the calibration procedure were analyzed, and the results of the calibration were provided. Then, laboratory experiments using the radiometer were described. The measurements of the surface temperature of a water sample that was contained in a thermostatic water bath, performed by using the radiometer, were compared to the water sample's temperature controlled by another device. These experiments were used to evaluate the calibration precision of the CE 312-2 ASTER radiometer, by means of assessing the measurement accuracy of the experiments. The results demonstrated that the calibration coefficients of the CE 312-2 ASTER thermal infrared radiometer displayed a very good performance, with highly accurate measurements, and could be used to detect phenomena related to a thermal infrared target.

  19. Radiation and Health Technology Laboratory Capabilities

    SciTech Connect

    Bihl, Donald E.; Lynch, Timothy P.; Murphy, Mark K.; Myers, Lynette E.; Piper, Roman K.; Rolph, James T.

    2005-07-09

    The Radiological Standards and Calibrations Laboratory, a part of Pacific Northwest National Laboratory (PNNL)(a) performs calibrations and upholds reference standards necessary to maintain traceability to national standards. The facility supports U.S. Department of Energy (DOE) programs at the Hanford Site, programs sponsored by DOE Headquarters and other federal agencies, radiological protection programs at other DOE and commercial nuclear sites and research and characterization programs sponsored through the commercial sector. The laboratory is located in the 318 Building of the Hanford Site's 300 Area. The facility contains five major exposure rooms and several laboratories used for exposure work preparation, low-activity instrument calibrations, instrument performance evaluations, instrument maintenance, instrument design and fabrication work, thermoluminescent and radiochromic Dosimetry, and calibration of measurement and test equipment (M&TE). The major exposure facilities are a low-scatter room used for neutron and photon exposures, a source well room used for high-volume instrument calibration work, an x-ray facility used for energy response studies, a high-exposure facility used for high-rate photon calibration work, a beta standards laboratory used for beta energy response studies and beta reference calibrations and M&TE laboratories. Calibrations are routinely performed for personnel dosimeters, health physics instrumentation, photon and neutron transfer standards alpha, beta, and gamma field sources used throughout the Hanford Site, and a wide variety of M&TE. This report describes the standards and calibrations laboratory.

  20. Radiation and Health Technology Laboratory Capabilities

    SciTech Connect

    Goles, Ronald W.; Johnson, Michelle Lynn; Piper, Roman K.; Peters, Jerry D.; Murphy, Mark K.; Mercado, Mike S.; Bihl, Donald E.; Lynch, Timothy P.

    2003-07-15

    The Radiological Standards and Calibrations Laboratory, a part of Pacific Northwest National Laboratory (PNNL)(a) performs calibrations and upholds reference standards necessary to maintain traceability to national standards. The facility supports U.S. Department of Energy (DOE) programs at the Hanford Site, programs sponsored by DOE Headquarters and other federal agencies, radiological protection programs at other DOE and commercial nuclear sites and research and characterization programs sponsored through the commercial sector. The laboratory is located in the 318 Building of the Hanford Site's 300 Area. The facility contains five major exposure rooms and several laboratories used for exposure work preparation, low-activity instrument calibrations, instrument performance evaluations, instrument maintenance, instrument design and fabrication work, thermoluminescent and radiochromic Dosimetry, and calibration of measurement and test equipment (M&TE). The major exposure facilities are a low-scatter room used for neutron and photon exposures, a source well room used for high-volume instrument calibration work, an x-ray facility used for energy response studies, a high-exposure facility used for high-rate photon calibration work, a beta standards laboratory used for beta energy response studies and beta reference calibrations and M&TE laboratories. Calibrations are routinely performed for personnel dosimeters, health physics instrumentation, photon and neutron transfer standards alpha, beta, and gamma field sources used throughout the Hanford Site, and a wide variety of M&TE. This report describes the standards and calibrations laboratory.

  1. Integrated verification experiment data collected as part of the Los Alamos National Laboratory`s Source Region program. Appendix F: Regional data from Lawrence Livermore National Laboratory and Sandia National Laboratory Seismic Networks

    SciTech Connect

    Taylor, S.R.

    1993-06-11

    A dataset of regional seismograms assembled for a series of Integrated Verification Experiments conducted by the Los Alamos National Laboratory Source Region program is described. The seismic data has been assembled from networks operated by Lawrence Livermore National Laboratory and Sandia National Laboratory. Examples of the data are shown and basic recording characteristics of the network are described. The seismograms are available on a data tape in SAC format upon request.

  2. Protein Structural Studies by Traveling Wave Ion Mobility Spectrometry: A Critical Look at Electrospray Sources and Calibration Issues.

    PubMed

    Sun, Yu; Vahidi, Siavash; Sowole, Modupeola A; Konermann, Lars

    2016-01-01

    The question whether electrosprayed protein ions retain solution-like conformations continues to be a matter of debate. One way to address this issue involves comparisons of collision cross sections (Ω) measured by ion mobility spectrometry (IMS) with Ω values calculated for candidate structures. Many investigations in this area employ traveling wave IMS (TWIMS). It is often implied that nanoESI is more conducive for the retention of solution structure than regular ESI. Focusing on ubiquitin, cytochrome c, myoglobin, and hemoglobin, we demonstrate that Ω values and collisional unfolding profiles are virtually indistinguishable under both conditions. These findings suggest that gas-phase structures and ion internal energies are independent of the type of electrospray source. We also note that TWIMS calibration can be challenging because differences in the extent of collisional activation relative to drift tube reference data may lead to ambiguous peak assignments. It is demonstrated that this problem can be circumvented by employing collisionally heated calibrant ions. Overall, our data are consistent with the view that exposure of native proteins to electrospray conditions can generate kinetically trapped ions that retain solution-like structures on the millisecond time scale of TWIMS experiments. ᅟ PMID:26369778

  3. Protein Structural Studies by Traveling Wave Ion Mobility Spectrometry: A Critical Look at Electrospray Sources and Calibration Issues

    NASA Astrophysics Data System (ADS)

    Sun, Yu; Vahidi, Siavash; Sowole, Modupeola A.; Konermann, Lars

    2016-01-01

    The question whether electrosprayed protein ions retain solution-like conformations continues to be a matter of debate. One way to address this issue involves comparisons of collision cross sections (Ω) measured by ion mobility spectrometry (IMS) with Ω values calculated for candidate structures. Many investigations in this area employ traveling wave IMS (TWIMS). It is often implied that nanoESI is more conducive for the retention of solution structure than regular ESI. Focusing on ubiquitin, cytochrome c, myoglobin, and hemoglobin, we demonstrate that Ω values and collisional unfolding profiles are virtually indistinguishable under both conditions. These findings suggest that gas-phase structures and ion internal energies are independent of the type of electrospray source. We also note that TWIMS calibration can be challenging because differences in the extent of collisional activation relative to drift tube reference data may lead to ambiguous peak assignments. It is demonstrated that this problem can be circumvented by employing collisionally heated calibrant ions. Overall, our data are consistent with the view that exposure of native proteins to electrospray conditions can generate kinetically trapped ions that retain solution-like structures on the millisecond time scale of TWIMS experiments.

  4. 10 CFR 70.19 - General license for calibration or reference sources.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... State who holds a specific license issued by the Commission or the Atomic Energy Commission which... the Commission or the Atomic Energy Commission which authorizes him to receive, possess, use and... effect on January 1, 1975. The receipt, possession, use and transfer of this source, Model ___, Serial...

  5. 10 CFR 70.19 - General license for calibration or reference sources.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... State who holds a specific license issued by the Commission or the Atomic Energy Commission which... the Commission or the Atomic Energy Commission which authorizes him to receive, possess, use and... effect on January 1, 1975. The receipt, possession, use and transfer of this source, Model ___, Serial...

  6. 10 CFR 70.19 - General license for calibration or reference sources.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... State who holds a specific license issued by the Commission or the Atomic Energy Commission which... the Commission or the Atomic Energy Commission which authorizes him to receive, possess, use and... effect on January 1, 1975. The receipt, possession, use and transfer of this source, Model ___, Serial...

  7. Determination of phosphorus source coefficients for organic phosphorus sources: laboratory studies.

    PubMed

    Leytem, A B; Sims, J T; Coale, F J

    2004-01-01

    Phosphorus losses in runoff from application of manures and biosolids to agricultural land are implicated in the degradation of water quality in the Chesapeake and Delaware Inland Bays. We conducted an incubation study to determine the relative P solubility and bioavailability, referred to as P source coefficients (PSCs), for organic P sources, which are typically land-applied in the Mid-Atlantic USA. Nine organic and one inorganic (KH2PO4) P amendments were applied to an Evesboro loamy sand (mesic, coated Typic Quartzipsamments) at a rate of 60 mg P kg(-1) and incubated for 8 wk with subsamples analyzed at 2 and 8 wk. There was an increase in Mehlich-3 P (M3-P), water-soluble P (WS-P), iron-oxide strip extractable P (FeO-P), and Mehlich-3 P saturation ratio (M3-PSR) with P additions, which varied by P source. The trend of relative extractable WS-P, FeO-P, and M3-P generally followed the pattern: inorganic P > liquid and deep pit manures > manures and biosolids treated with metal salts or composted. We found significant differences in the availability of P from varying organic P sources. The use of PSCs may be beneficial when determining the risk of P losses from land application of manures and other organic P sources and could be used in risk assessments such as a P site index. These PSCs may also be useful for determining P application rates when organic P sources are applied to P deficient soils for use as a fertilizer source. PMID:14964394

  8. A multi-source satellite data approach for modelling Lake Turkana water level: Calibration and validation using satellite altimetry data

    USGS Publications Warehouse

    Velpuri, N.M.; Senay, G.B.; Asante, K.O.

    2012-01-01

    Lake Turkana is one of the largest desert lakes in the world and is characterized by high degrees of interand intra-annual fluctuations. The hydrology and water balance of this lake have not been well understood due to its remote location and unavailability of reliable ground truth datasets. Managing surface water resources is a great challenge in areas where in-situ data are either limited or unavailable. In this study, multi-source satellite-driven data such as satellite-based rainfall estimates, modelled runoff, evapotranspiration, and a digital elevation dataset were used to model Lake Turkana water levels from 1998 to 2009. Due to the unavailability of reliable lake level data, an approach is presented to calibrate and validate the water balance model of Lake Turkana using a composite lake level product of TOPEX/Poseidon, Jason-1, and ENVISAT satellite altimetry data. Model validation results showed that the satellitedriven water balance model can satisfactorily capture the patterns and seasonal variations of the Lake Turkana water level fluctuations with a Pearson's correlation coefficient of 0.90 and a Nash-Sutcliffe Coefficient of Efficiency (NSCE) of 0.80 during the validation period (2004-2009). Model error estimates were within 10% of the natural variability of the lake. Our analysis indicated that fluctuations in Lake Turkana water levels are mainly driven by lake inflows and over-the-lake evaporation. Over-the-lake rainfall contributes only up to 30% of lake evaporative demand. During the modelling time period, Lake Turkana showed seasonal variations of 1-2m. The lake level fluctuated in the range up to 4m between the years 1998-2009. This study demonstrated the usefulness of satellite altimetry data to calibrate and validate the satellite-driven hydrological model for Lake Turkana without using any in-situ data. Furthermore, for Lake Turkana, we identified and outlined opportunities and challenges of using a calibrated satellite-driven water balance

  9. Practical application of electromyogram radiotelemetry: the suitability of applying laboratory-acquired calibration data to field data

    SciTech Connect

    Geist, David R. ); Brown, Richard S.; Lepla, Ken; Chandler, James P.

    2001-12-01

    One of the practical problems with quantifying the amount of energy used by fish implanted with electromyogram (EMG) radio transmitters is that the signals emitted by the transmitter provide only a relative index of activity unless they are calibrated to the swimming speed of the fish. Ideally calibration would be conducted for each fish before it is released, but this is often not possible and calibration curves derived from more than one fish are used to interpret EMG signals from individuals which have not been calibrated. We tested the validity of this approach by comparing EMG data within three groups of three wild juvenile white sturgeon Acipenser transmontanus implanted with the same EMG radio transmitter. We also tested an additional six fish which were implanted with separate EMG transmitters. Within each group, a single EMG radio transmitter usually did not produce similar results in different fish. Grouping EMG signals among fish produced less accurate results than having individual EMG-swim speed relationships for each fish. It is unknown whether these differences were a result of different swimming performances among individual fish or inconsistencies in the placement or function of the EMG transmitters. In either case, our results suggest that caution should be used when applying calibration curves from one group of fish to another group of uncalibrated fish.

  10. Applications of an 88Y/Be photoneutron calibration source to dark matter and neutrino experiments.

    PubMed

    Collar, J I

    2013-05-24

    The low-energy monochromatic neutron emission from an (88)Y/Be source can be exploited to mimic the few keV(nr) nuclear recoils expected from low-mass weakly interacting massive particles and coherent scattering of neutrinos off nuclei. Using this source, a

  11. Applications of an 88Y/Be photoneutron calibration source to dark matter and neutrino experiments.

    PubMed

    Collar, J I

    2013-05-24

    The low-energy monochromatic neutron emission from an (88)Y/Be source can be exploited to mimic the few keV(nr) nuclear recoils expected from low-mass weakly interacting massive particles and coherent scattering of neutrinos off nuclei. Using this source, a

  12. Comparison of laboratory calibrations of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) at the beginning and end of the first flight season

    NASA Technical Reports Server (NTRS)

    Vane, Gregg; Chrien, Thomas G.; Reimer, John H.; Green, Robert O.; Conel, James E.

    1988-01-01

    Spectral and radiometric calibrations of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) were performed in the laboratory in June and November, 1987, at the beginning and end of the first flight season. Those calibrations are described along with changes in instrument characteristics that occurred during the flight season as a result of factors such as detachment of the optical fibers to two of the four AVIRIS spectrometers, degradation in the optical alignment of the spectrometers due to thermally-induced and mechanical warpage, and breakage of a thermal blocking filter in one of the spectrometers. These factors caused loss of signal in three spectrometers, loss of spectral resolution in two spectrometers, and added uncertainty in the radiometry of AVIRIS. Results from in-flight assessment of the laboratory calibrations are presented. A discussion is presented of improvements made to the instrument since the end of the first flight season and plans for the future. Improvements include: (1) a new thermal control system for stabilizing spectrometer temperatures, (2) kinematic mounting of the spectrometers to the instrument rack, and (3) new epoxy for attaching the optical fibers inside their mounting tubes.

  13. The Neuro/PsyGRID calibration experiment: identifying sources of variance and bias in multicenter MRI studies.

    PubMed

    Suckling, John; Barnes, Anna; Job, Dominic; Brennan, David; Lymer, Katherine; Dazzan, Paola; Marques, Tiago Reis; MacKay, Clare; McKie, Shane; Williams, Steve R; Williams, Steven C R; Deakin, Bill; Lawrie, Stephen

    2012-02-01

    Calibration experiments precede multicenter trials to identify potential sources of variance and bias. In support of future imaging studies of mental health disorders and their treatment, the Neuro/PsyGRID consortium commissioned a calibration experiment to acquire functional and structural MRI from twelve healthy volunteers attending five centers on two occasions. Measures were derived of task activation from a working memory paradigm, fractal scaling (Hurst exponent) from resting fMRI, and grey matter distributions from T(1) -weighted sequences. At each intracerebral voxel a fixed-effects analysis of variance estimated components of variance corresponding to factors of center, subject, occasion, and within-occasion order, and interactions of center-by-occasion, subject-by-occasion, and center-by-subject, the latter (since there is no intervention) a surrogate of the expected variance of the treatment effect standard error across centers. A rank order test of between-center differences was indicative of crossover or noncrossover subject-by-center interactions. In general, factors of center, subject and error variance constituted >90% of the total variance, whereas occasion, order, and all interactions were generally <5%. Subject was the primary source of variance (70%-80%) for grey-matter, with error variance the dominant component for fMRI-derived measures. Spatially, variance was broadly homogenous with the exception of fractal scaling measures which delineated white matter, related to the flip angle of the EPI sequence. Maps of P values for the associated F-tests were also derived. Rank tests were highly significant indicating the order of measures across centers was preserved. In summary, center effects should be modeled at the voxel-level using existing and long-standing statistical recommendations.

  14. Development of Fiber Fabry-Perot Interferometers as Stable Near-infrared Calibration Sources for High Resolution Spectrographs

    NASA Astrophysics Data System (ADS)

    Halverson, Samuel; Mahadevan, Suvrath; Ramsey, Lawrence; Hearty, Fred; Wilson, John; Holtzman, Jon; Redman, Stephen; Nave, Gillian; Nidever, David; Nelson, Matt; Venditti, Nick; Bizyaev, Dmitry; Fleming, Scott

    2014-05-01

    We discuss the ongoing development of single-mode fiber Fabry-Perot (FFP) Interferometers as precise astrophotonic calibration sources for high precision radial velocity (RV) spectrographs. FFPs are simple, inexpensive, monolithic units that can yield a stable and repeatable output spectrum. An FFP is a unique alternative to a traditional etalon, as the interferometric cavity is made of single-mode fiber rather than an air-gap spacer. This design allows for excellent collimation, high spectral finesse, rigid mechanical stability, insensitivity to vibrations, and no need for vacuum operation. The device we have tested is a commercially available product from Micron Optics.10 Our development path is targeted toward a calibration source for the Habitable-Zone Planet Finder (HPF), a near-infrared spectrograph designed to detect terrestrial-mass planets around low-mass stars, but this reference could also be used in many existing and planned fiber-fed spectrographs as we illustrate using the Apache Point Observatory Galactic Evolution Experiment (APOGEE) instrument. With precise temperature control of the fiber etalon, we achieve a thermal stability of 100 μK and associated velocity uncertainty of 22 cm s-1. We achieve a precision of ≈2 m s-1 in a single APOGEE fiber over 12 hr using this new photonic reference after removal of systematic correlations. This high precision (close to the expected photon-limited floor) is a testament to both the excellent intrinsic wavelength stability of the fiber interferometer and the stability of the APOGEE instrument design. Overall instrument velocity precision is 80 cm s-1 over 12 hr when averaged over all 300 APOGEE fibers and after removal of known trends and pressure correlations, implying the fiber etalon is intrinsically stable to significantly higher precision.

  15. VNIR, MWIR, and LWIR source assemblies for optical quality testing and spectro-radiometric calibration of earth observation satellites

    NASA Astrophysics Data System (ADS)

    Compain, Eric; Maquet, Philippe; Leblay, Pierrick; Gavaud, Eric; Marque, Julien; Glastre, Wilfried; Cortese, Maxime; Sugranes, Pierre; Gaillac, Stephanie; Potheau, Hervé

    2015-09-01

    This document presents several original OGSEs, Optical Ground Support Equipment, specifically designed and realized for the optical testing and calibration of earth observation satellites operating in a large spectral band from 0.4μm to 14.7μm. This work has been mainly supported by recent development dedicated to MTG, Meteosat Third Generation, the ESA next generation of meteorological satellites. The improved measurement capabilities of this new satellite generation has generated new challenging requirements for the associated optical test equipments. These improvements, based on design and component innovation will be illustrated for the MOTA, the GICS and the DEA OGSEs. MOTA and GICS are dedicated to the AIT, Assembly Integration and Test, of FCI, the Flexible Combined Imager of the imaging satellite MTG-I. DEA OGSE is dedicated to the AIT of the DEA, Detection Electronics Assembly, which is part of IRS instrument, an IR sounder part of MTG-S satellite. From an architectural point of view, the presented original designs enable to run many optical tests with a single system thanks to a limited configuration effort. Main measurement capabilities are optical quality testing (MTF based mainly on KEF measurement), Line of Sight (LoS) stability measurement, straylight analyses, VNIR-MWIR-LWIR focal plane array co-registration, and broadband large dynamic spectro-radiometric calibration. Depending on the AIT phase of the satellite, these source assemblies are operated at atmospheric pressure or under secondary vacuum. In operation, they are associated with an opto-mechanical projection system that enables to conjugate the image of the source assembly with the focal plane of the satellite instruments. These conjugation systems are usually based on high resolution, broadband collimator, and are optionally mounted on hexapod to address the entire field of instruments.

  16. The standardization methods of radioactive sources (125I, 131I, 99mTc, and 18F) for calibrating nuclear medicine equipment in Indonesia

    NASA Astrophysics Data System (ADS)

    Wurdiyanto, G.; Candra, H.

    2016-03-01

    The standardization of radioactive sources (125I, 131I, 99mTc and 18F) to calibrate the nuclear medicine equipment had been carried out in PTKMR-BATAN. This is necessary because the radioactive sources used in the field of nuclear medicine has a very short half-life in other that to obtain a quality measurement results require special treatment. Besides that, the use of nuclear medicine techniques in Indonesia develop rapidly. All the radioactive sources were prepared by gravimetric methods. Standardization of 125I has been carried out by photon- photon coincidence methods, while the others have been carried out by gamma spectrometry methods. The standar sources are used to calibrate a Capintec CRC-7BT radionuclide calibrator. The results shows that calibration factor for Capintec CRC-7BT dose calibrator is 1,03; 1,02; 1,06; and 1,04 for 125I, 131I, 99mTc and 18F respectively, by about 5 to 6% of the expanded uncertainties.

  17. Students' Strengths and Weaknesses in Evaluating Technical Arguments as Revealed through Implementing Calibrated Peer Review™ in a Bioengineering Laboratory

    ERIC Educational Resources Information Center

    Volz, Tracy; Saterbak, Ann

    2009-01-01

    In engineering fields, students are expected to construct technical arguments that demonstrate a discipline's expected use of logic, evidence, and conventions. Many undergraduate bioengineering students struggle to enact the appropriate argument structures when they produce technical posters. To address this problem we implemented Calibrated Peer…

  18. Calibration of the Lawrence Livermore National Laboratory Passive-Active Neutron Drum Shuffler for Measurement of Highly Enriched Uranium in Mixed Oxide

    SciTech Connect

    Mount, M; O'Connell, W; Cochran, C; Rinard, P; Dearborn, D; Endres, E

    2002-05-23

    As a follow-on to the Lawrence Livermore National Laboratory (LLNL) effort to calibrate the LLNL passive-active neutron drum (PAN) shuffler for measurement of highly enriched uranium (HEU) oxide, a method has been developed to extend the use of the PAN shuffler to the measurement of HEU in mixed uranium-plutonium (U-Pu) oxide. This method uses the current LLNL HEU oxide calibration algorithms, appropriately corrected for the mixed U-Pu oxide assay time, and recently developed PuO{sub 2} calibration algorithms to yield the mass of {sup 235}U present via differences between the expected count rate for the PuO{sub 2} and the measured count rate of the mixed U-Pu oxide. This paper describes the LLNL effort to use PAN shuffler measurements of units of certified reference material (CRM) 149 [uranium (93% Enriched) Oxide - U{sub 3}O{sub 8} Standard for Neutron Counting Measurements] and CRM 146 [Uranium Isotopic Standard for Gamma Spectrometry Measurements] and a selected set of LLNL PuO{sub 2}-bearing containers in consort with Monte Carlo simulations of the PAN shuffler response to each to (1) establish and validate a correction to the HEU calibration algorithm for the mixed U-Pu oxide assay time, (2) develop a PuO{sub 2} calibration algorithm that includes the effect of PuO{sub 2} density (2.4 g/cm{sup 3} to 4.8 g/cm{sup 3}) and container size (8.57 cm to 9.88 cm inside diameter and 9.60 cm to 13.29 cm inside height) on the PAN shuffler response, and (3) develop and validate the method for establishing the mass of {sup 235}U present in an unknown of mixed U-Pu oxide.

  19. The design, construction and calibration of a carefully controlled source for exposure of mammalian cells to extremely low-frequency electromagnetic fields.

    PubMed

    Wolff, H; Gamble, S; Barkley, T; Janaway, L; Jowett, F; Halls, J A; Arrand, J E

    1999-09-01

    Despite some epidemiological evidence for an association between increased risk of cancer and exposure to electromagnetic fields (EMFs), cancer causation by such exposure remains unproven. Furthermore, for reasons such as biological unresponsiveness of the chosen system, poor equipment design and experimental confounders, no reproducible effects on animals or mammalian cells in culture have been demonstrated following exposure to power frequency EMFs at levels normally encountered in residential settings (<10 to 1000 microT). The apparatus described here, designed specifically to perform large, well-controlled cell biology experiments, reduces extraneous variables to the absolute minimum, so that small effects cannot be ascribed to some cause unrelated to the experimental protocol. Our novel apparatus consists of two identical solenoids which, in use, only differ by whether the field-producing current is flowing or not; they do not influence one another in any way. They are supplied with conditioned air from a common tissue culture incubator, are completely screened from environmental a.c. fields with Mumetal shielding and can be operated under normal laboratory conditions. Furthermore, the arrangement is such that the investigator is unaware whether cells have, or have not, been exposed until after the results have been evaluated. We report the design, construction, calibration and potential uses of this source.

  20. Ultraviolet stimulated electron source for use with low energy plasma instrument calibration

    NASA Astrophysics Data System (ADS)

    Henderson, Kevin; Harper, Ron; Funsten, Herb; MacDonald, Elizabeth

    2012-07-01

    We have developed and demonstrated a versatile, compact electron source that can produce a mono-energetic electron beam up to 50 mm in diameter from 0.1 to 30 keV with an energy spread of <10 eV. By illuminating a metal cathode plate with a single near ultraviolet light emitting diode, a spatially uniform electron beam with 15% variation over 1 cm2 can be generated. A uniform electric field in front of the cathode surface accelerates the electrons into a beam with an angular divergence of <1° at 1 keV. The beam intensity can be controlled from 10 to 109 electrons cm-2 s-1.

  1. Dosimetric characteristics, air-kerma strength calibration and verification of Monte Carlo simulation for a new ytterbium-169 brachytherapy source

    SciTech Connect

    Perera, H.; Williamson, J.F.; Li, Zuofeng; Mishra, V.; Meigooni, A.S. )

    1994-03-01

    Ytterbium-169 ([sup 169]Yb) is a promising new isotope for brachytherapy with a half life of 32 days and an average photon energy of 93 KeV. It has an Ir-192-equivalent dose distribution in water but a much smaller half-value layer in lead (0.2 mm), affording improved radiation protection and customized shielding of dose-limiting anatomic structures. The goals of this study are to: (a) experimentally validate Monte Carlo photon transport dose-rate calculations for this energy range, (b) to develop a secondary air-kerma strength standard for [sup 169]Yb, and (c) to present essential treatment planning data including the transverse-axis dose-rate distribution and dose correction factors for a number of local shielding materials. Several interstitial [sup 169]Yb sources (type 6) and an experimental high dose-rate source were made available for this study. Monte Carlo photon-transport (MCPT) simulations, based upon validated geometric models of source structure, were used to calculate dose rates in water. To verify MCPT predictions, the transverse-axis dose distribution in homogeneous water medium was measured using a silicon-diode detector. For use in designing shielded applicators, heterogeneity correction factors (HCF) arising from small cylindrical heterogeneities of lead, aluminum, titanium, steel and air were measured in a water medium. Finally, to provide a sound experimental basis for comparing experimental and theoretical dose-rate distributions, the air-kerma strength of the sources was measured using a calibrated ion chamber. To eliminate the influence of measurement artifacts on the comparison of theory and measurement, simulated detector readings were compared directly to measured diode readings. The final data are presented in the format endorsed by the Interstitial Collaborative Working Group. 33 refs., 8 figs., 3 tabs.

  2. Image Calibration

    NASA Technical Reports Server (NTRS)

    Peay, Christopher S.; Palacios, David M.

    2011-01-01

    Calibrate_Image calibrates images obtained from focal plane arrays so that the output image more accurately represents the observed scene. The function takes as input a degraded image along with a flat field image and a dark frame image produced by the focal plane array and outputs a corrected image. The three most prominent sources of image degradation are corrected for: dark current accumulation, gain non-uniformity across the focal plane array, and hot and/or dead pixels in the array. In the corrected output image the dark current is subtracted, the gain variation is equalized, and values for hot and dead pixels are estimated, using bicubic interpolation techniques.

  3. openBIS ELN-LIMS: an open-source database for academic laboratories

    PubMed Central

    Barillari, Caterina; Ottoz, Diana S. M.; Fuentes-Serna, Juan Mariano; Ramakrishnan, Chandrasekhar; Rinn, Bernd; Rudolf, Fabian

    2016-01-01

    Summary: The open-source platform openBIS (open Biology Information System) offers an Electronic Laboratory Notebook and a Laboratory Information Management System (ELN-LIMS) solution suitable for the academic life science laboratories. openBIS ELN-LIMS allows researchers to efficiently document their work, to describe materials and methods and to collect raw and analyzed data. The system comes with a user-friendly web interface where data can be added, edited, browsed and searched. Availability and implementation: The openBIS software, a user guide and a demo instance are available at https://openbis-eln-lims.ethz.ch. The demo instance contains some data from our laboratory as an example to demonstrate the possibilities of the ELN-LIMS (Ottoz et al., 2014). For rapid local testing, a VirtualBox image of the ELN-LIMS is also available. Contact: brinn@ethz.ch or fabian.rudolf@bsse.ethz.ch PMID:26508761

  4. SEISMIC SOURCE AND PATH CALIBRATION IN THE KOREAN PENINSULA, YELLOW SEA

    SciTech Connect

    Herrmann, R B; Walter, W R; Pasyanos, M

    2007-07-11

    Two significant seismic events were analyzed using the crustal velocity model developed under this contract. The M{sub W} = 4.55 Korea earthquake of January 20, 2007 occurred in the Republic of Korea on land and within the dense digital seismic network. Using P-wave arrivals from 60 broadband, short-period and acceleration stations, the event occurred at 37.68N, 128.58E at a depth of 7.5 km at 20070120115653.8. Source inversion was performed using the accelerometer recordings in the 0.05-0.20 Hz band the broadband data in the 0.02-0.10 Hz band, with identical focal mechanisms and source depths of 9 and 11 km, respectively. This is the largest event on land in South Korea since the M{sub W} 4.7 event on December 13, 1996. Forward modeling of the waveforms at INCN and MDJ indicates the ability of the current model to match observations on the Korean Peninsula and the effect of significant pulse shape modification for paths that partially cross the Sea of Japan. The results of using the local network data provide a ground truth point for other studies analyzing seismic events on the peninsula. The isotropic seismic moment of the October 9, 2006 North Korea explosion was estimated from the Rayleigh-wave spectral amplitudes observed at MDJ and INCN. Very little Love wave signal was observed, indicating weak tectonic release. The explosion yield was investigated using the Denny and Johnson (1991) model relating yield to the observed isotropic moment as a function of depth of burial and material properties. Sensitivity analysis highlights the strong effect of the assumed velocity and density structure in the upper kilometer of the Earth and the assumed depth of burial on the estimated yield. The crustal velocity model developed under this contract provides strong constraints on the expected shear-wave velocities in the shallow parts of the crust. Issues to be investigated include the effect of wave propagation through the Eastern Sea (Sea of Japan) to stations in South

  5. Status report on the Advanced Photon Source Project at Argonne National Laboratory

    SciTech Connect

    Huebner, R.H. Sr.

    1989-01-01

    The Advanced Photon Source at Argonne National Laboratory is designed as a national synchrotron radiation user facility which will provide extremely bright, highly energetic x-rays for multidisciplinary research. When operational, the Advanced Photon Source will accelerate positrons to a nominal energy of 7 GeV. The positrons will be manipulated by insertion devices to produce x-rays 10,000 times brighter than any currently available for research. Accelerator components, insertion devices, optical elements, and optical-element cooling schemes have been and continue to be the subjects of intensive research and development. A call for Letters of Intent from prospective users of the Advanced Photon Source has resulted in a substantial response from industrial, university, and national laboratory researchers.

  6. Status report on the Advanced Photon Source Project at Argonne National Laboratory

    SciTech Connect

    Huebner, R.H. Sr.

    1989-12-31

    The Advanced Photon Source at Argonne National Laboratory is designed as a national synchrotron radiation user facility which will provide extremely bright, highly energetic x-rays for multidisciplinary research. When operational, the Advanced Photon Source will accelerate positrons to a nominal energy of 7 GeV. The positrons will be manipulated by insertion devices to produce x-rays 10,000 times brighter than any currently available for research. Accelerator components, insertion devices, optical elements, and optical-element cooling schemes have been and continue to be the subjects of intensive research and development. A call for Letters of Intent from prospective users of the Advanced Photon Source has resulted in a substantial response from industrial, university, and national laboratory researchers.

  7. A proposal for a long-pulse spallation source at Los Alamos National Laboratory

    SciTech Connect

    Pynn, R.; Weinacht, D.

    1995-12-01

    Los Alamos National Laboratory is proposing a new spallation neutron source that will provide the US with an internationally competitive facility for neutron science and technology that can be built in approximately three years for less than $100 million. The establishment of a 1-MW, long-pulse spallation source (LPSS) at the Los Alamos Neutron Science Center (LANSCE) will meet many of the present needs of scientists in the neutron scattering community and provide a significant boost to neutron research in the US. The new facility will support the development of a future, more intense spallation neutron source, that is planned by DOE`s Office of Energy Research. Together with the existing short pulse spallation source (SPSS) at the Manual Lujan, Jr. Neutron Scattering Center (MLNSC) at Los Alamos, the new LPSS will provide US scientists with a complementary pair of high-performance neutron sources to rival the world`s leading facilities in Europe.

  8. Assessment of nonpoint-source runoff in a stream using in situ and laboratory approaches

    SciTech Connect

    Tucker, K.A.; Burton, G.A. Jr.

    1999-12-01

    Anthropogenic activities that change a watershed can cause adverse impacts to receiving water. Agricultural and urban runoff are the two leading causes of surface-water impairment in the US. When assessing pollutant sources and their effects on aquatic ecosystems, and prior to implementing source controls, it is necessary to define the systems stressors and receptors of exposure. Toxicity assays are a key component to integrative assessments that include habitat (physical), chemical, and indigenous community characterization. Traditional toxicity assay methods and the use of water-quality criteria are often inappropriate because of exposure design and effect assumptions. Hyalella azteca and Chironomus tentans were exposed in situ for varying time periods during both low- and high-flow conditions to determine the effect of urban and agricultural runoff. Short-term chronic and acute toxicity of urban and agricultural runoff was then measured in the laboratory and related to in situ test results. Nonpoint-source (NPS) runoff from urban areas was often more acutely toxic to organisms in the laboratory as compared to in situ results. Conversely, toxicity to the organisms was greater at the agricultural site during in situ exposures when compared to laboratory. In situ assays were an essential and integral component of NPS runoff assessments. They provided unique information that complemented laboratory toxicity, habitat, benthic community, and physicochemical characterizations.

  9. KEY COMPARISON: Final report of comparison of the calibrations of hydrometers for liquid density determination between SIM laboratories: SIM.M.D-K4

    NASA Astrophysics Data System (ADS)

    Becerra, Luis Omar

    2009-01-01

    This SIM comparison on the calibration of high accuracy hydrometers was carried out within fourteen laboratories in the density range from 600 kg/m3 to 1300 kg/m3 in order to evaluate the degree of equivalence among participant laboratories. This key comparison anticipates the planned key comparison CCM.D-K4, and is intended to be linked with CCM.D-K4 when results are available. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  10. Radioactive Standards Laboratory ININ as a reference laboratory in Mexico.

    PubMed

    GarcíaDíaz, O; MartínezAyala, L; HerreraValadez, L; TovarM, V; Karam, L

    2016-03-01

    The Radioactive Standards Laboratory of the National Institute of Nuclear Research is the National reference laboratory for the measurement of radioactivity in Mexico. It has a gamma-ray spectrometry system with a high-purity Ge-detector for measurements from 50 keV to 2000 keV, and develops standardized radioactive (beta-particle and gamma-ray emitting) sources in different geometries with uncertainties less than or equal to 5% for applications such as the calibration of radionuclide calibrators (clinically used dose calibrators), Ge-detectors and NaI(Tl) detectors. PMID:27358942

  11. Broad-band calibration of marine seismic sources used by R/V Polarstern for academic research in polar regions

    NASA Astrophysics Data System (ADS)

    Breitzke, Monika; Boebel, Olaf; El Naggar, Saad; Jokat, Wilfried; Werner, Berthold

    2008-08-01

    Air guns and air-gun arrays of different volumes are used for scientific seismic surveys with R/V Polarstern in polar regions. To assess the potential risk of these research activities on marine mammal populations, knowledge of the sound pressure field of the seismic sources is essential. Therefore, a broad-band (0-80 kHz) calibration study was conducted at the Heggernes Acoustic Range, Norway. A GI (2.4 l), a G (8.5 l) and a Bolt gun (32.8 l) were deployed as single sources, 3 GI (7.4 l), 3 G (25.6 l) and 8 VLF™ Prakla-Seismos air guns (24.0 l) as arrays. Each configuration was fired along a line of 3-4 km length running between two hydrophone chains with receivers in 35, 100, 198 and 263 m depth. Peak-to-peak, zero-to-peak, rms and sound exposure levels (SEL) were analysed as functions of range. They show the typical dipole-like directivity of marine seismic sources with amplitude cancellation close to the sea surface, higher amplitudes in greater depths, and sound pressure levels which continuously decrease with range. Levels recorded during the approach are lower than during the departure indicating a shadowing effect of Polarsterns's hull. Backcalculated zero-to-peak source levels range from 224-240 dB re 1 μPa @ 1 m. Spectral source levels are highest below 100 Hz and amount to 182-194 dB re 1 μPa Hz-1. They drop off continuously with range and frequency. At 1 kHz they are ~30 dB, at 80 kHz ~60 dB lower than the peak level. Above 1 kHz amplitude spectra are dominated by Polarstern's self-noise. From the rms and sound exposure levels of the deepest hydrophone radii for different thresholds are derived. For a 180 dB rms-level threshold radii maximally vary between 200 and 600 m, for a 186 dB SEL threshold between 50 and 300 m.

  12. Update on Calibration of the Lawrence Livermore National Laboratory Passive-Active Neutron Drum Shuffler for Measurement of Highly Enriched Uranium Oxide

    SciTech Connect

    Mount, M; O'Connell, W; Cochran, C; Rinard, P; Dearborn, D; Endres, E

    2002-05-17

    In October of 1999, Lawrence Livermore National Laboratory (LLNL) began an effort to calibrate the LLNL passive-active neutron (PAN) drum shuffler for measurement of highly enriched uranium (HEU) oxide. A single unit of certified reference material (CRM) 149 [Uranium (93% Enriched) Oxide - U{sub 3}O{sub 8} Standard for Neutron Counting Measurements] was used to (1) develop a mass calibration curve for HEU oxide in the nominal range of 393 g to 3144 g {sup 235}U, and (2) perform a detailed axial and radial mapping of the detector response over a wide region of the PAN shuffler counting chamber. Results from these efforts were reported at the Institute of Nuclear Materials Management 41st Annual Meeting in July 2000. This paper describes subsequent efforts by LLNL to use a unit of CRM 146 [Uranium Isotopic Standard for Gamma Spectrometry Measurements] in consort with Monte Carlo simulations of the PAN shuffler response to CRM 149 and CRM 146 units and a selected set of containers with CRM 149-equivalent U{sub 3}O{sub 8} to (1) extend the low range of the reported mass calibration curve to 10 g {sup 235}U, (2) evaluate the effect of U{sub 3}O{sub 8} density (2.4 g/cm{sup 3} to 4.8 g/cm{sup 3}) and container size (5.24 cm to 12.17 cm inside diameter and 6.35 cm to 17.72 cm inside height) on the PAN shuffler response, and (3) develop mass calibration curves for U{sub 3}O{sub 8} enriched to 20.1 wt% {sup 235}U and 52.5 wt% {sup 235}U.

  13. The Optics and Alignment of the Divergent Beam Laboratory X-ray Powder Diffractometer and its Calibration Using NIST Standard Reference Materials

    PubMed Central

    Cline, James P.; Mendenhall, Marcus H.; Black, David; Windover, Donald; Henins, Albert

    2015-01-01

    The laboratory X-ray powder diffractometer is one of the primary analytical tools in materials science. It is applicable to nearly any crystalline material, and with advanced data analysis methods, it can provide a wealth of information concerning sample character. Data from these machines, however, are beset by a complex aberration function that can be addressed through calibration with the use of NIST Standard Reference Materials (SRMs). Laboratory diffractometers can be set up in a range of optical geometries; considered herein are those of Bragg-Brentano divergent beam configuration using both incident and diffracted beam monochromators. We review the origin of the various aberrations affecting instruments of this geometry and the methods developed at NIST to align these machines in a first principles context. Data analysis methods are considered as being in two distinct categories: those that use empirical methods to parameterize the nature of the data for subsequent analysis, and those that use model functions to link the observation directly to a specific aspect of the experiment. We consider a multifaceted approach to instrument calibration using both the empirical and model based data analysis methods. The particular benefits of the fundamental parameters approach are reviewed. PMID:26958446

  14. New radiation protection calibration facility at CERN.

    PubMed

    Brugger, Markus; Carbonez, Pierre; Pozzi, Fabio; Silari, Marco; Vincke, Helmut

    2014-10-01

    The CERN radiation protection group has designed a new state-of-the-art calibration laboratory to replace the present facility, which is >20 y old. The new laboratory, presently under construction, will be equipped with neutron and gamma sources, as well as an X-ray generator and a beta irradiator. The present work describes the project to design the facility, including the facility placement criteria, the 'point-zero' measurements and the shielding study performed via FLUKA Monte Carlo simulations.

  15. DOE radiological calibrations intercomparison program: Results of fiscal year 1988

    SciTech Connect

    Cummings, F.M.; McDonald, J.C.; Murphy, M.K.

    1989-08-01

    Calibration measurements for personnel dosimetry purposes must be both accurate and consistent with national standards. In order to satisfy these requirements, the following methods are usually employed. In one case, a radiation source is sent to the National Institute of Standards and Technology (NIST), formerly the National Bureau of Standards, for calibration and is returned to the laboratory to be used as a local standard. Another method involves the calibration of an instrument, such as an ionization chamber, by NIST. After calibration, this instrument is then used to measure the exposure rate delivered by radiation sources at the laboratory. Such calibrations by NIST are essential, but they do not provide a complete check on the quality of the calibrations that are carried out by the individual laboratory. Additional measurements are necessary to assure the quality of such measurements. When laboratory staff are asked to carry our measurements with calibrated instruments and report results for evaluation, they are participating in a measurement quality assurance (MQA) program. Such a program tests not only the quality of the equipment but also the ability of the staff to correctly use and interpret the results obtained with the equipment. The NIST operates an MQA program with a selected number of calibration laboratories. Pacific Northwest Laboratory (PNL) participates in this MQA program even though NIST test only x-ray and gamma-ray measurements. The US Department of Energy (DOE) intercomparison program was designed specifically to include x-ray, gamma-ray, beta, and neutron calibrations for personnel dosimetry purposes. This program serves a need that is not being met by NIST, and it provides documentation of the accuracy and uniformity of the radiological calibrations carried out in DOE facilities. 7 refs., 3 figs., 6 tabs.

  16. ALARA considerations for the whole body neutron irradiation facility source removal project at Brookhaven National Laboratory.

    PubMed

    Sullivan, Patrick T

    2006-02-01

    This paper describes the activities that were involved with the safe removal of fourteen PuBe sources from the Brookhaven National Laboratory (BNL) Whole Body Neutron Irradiation Facility (WBNIF). As part of a Department of Energy and BNL effort to reduce the radiological inventory, the WBNIF was identified as having no future use. In order to deactivate the facility and eliminate the need for nuclear safety management and long-term surveillance, it was decided to remove the neutron sources and dismantle the facility. In addition, the sources did not have DOT Special Form documentation so they would need to be encapsulated once removed for offsite storage or disposal. The planning and the administrative as well as engineering controls put in place enabled personnel to safely remove and encapsulate the sources while keeping exposure as low as reasonably achievable (ALARA). PMID:16404183

  17. Mean-free-paths in concert and chamber music halls and the correct method for calibrating dodecahedral sound sources.

    PubMed

    Beranek, Leo L; Nishihara, Noriko

    2014-01-01

    The Eyring/Sabine equations assume that in a large irregular room a sound wave travels in straight lines from one surface to another, that the surfaces have an average sound absorption coefficient αav, and that the mean-free-path between reflections is 4 V/Stot where V is the volume of the room and Stot is the total area of all of its surfaces. No account is taken of diffusivity of the surfaces. The 4 V/Stot relation was originally based on experimental determinations made by Knudsen (Architectural Acoustics, 1932, pp. 132-141). This paper sets out to test the 4 V/Stot relation experimentally for a wide variety of unoccupied concert and chamber music halls with seating capacities from 200 to 5000, using the measured sound strengths Gmid and reverberation times RT60,mid. Computer simulations of the sound fields for nine of these rooms (of varying shapes) were also made to determine the mean-free-paths by that method. The study shows that 4 V/Stot is an acceptable relation for mean-free-paths in the Sabine/Eyring equations except for halls of unusual shape. Also demonstrated is the proper method for calibrating the dodecahedral sound source used for measuring the sound strength G, i.e., the reverberation chamber method. PMID:24437762

  18. Mean-free-paths in concert and chamber music halls and the correct method for calibrating dodecahedral sound sources.

    PubMed

    Beranek, Leo L; Nishihara, Noriko

    2014-01-01

    The Eyring/Sabine equations assume that in a large irregular room a sound wave travels in straight lines from one surface to another, that the surfaces have an average sound absorption coefficient αav, and that the mean-free-path between reflections is 4 V/Stot where V is the volume of the room and Stot is the total area of all of its surfaces. No account is taken of diffusivity of the surfaces. The 4 V/Stot relation was originally based on experimental determinations made by Knudsen (Architectural Acoustics, 1932, pp. 132-141). This paper sets out to test the 4 V/Stot relation experimentally for a wide variety of unoccupied concert and chamber music halls with seating capacities from 200 to 5000, using the measured sound strengths Gmid and reverberation times RT60,mid. Computer simulations of the sound fields for nine of these rooms (of varying shapes) were also made to determine the mean-free-paths by that method. The study shows that 4 V/Stot is an acceptable relation for mean-free-paths in the Sabine/Eyring equations except for halls of unusual shape. Also demonstrated is the proper method for calibrating the dodecahedral sound source used for measuring the sound strength G, i.e., the reverberation chamber method.

  19. Laboratory Astrophysics with High Power Lasers and 4th Generation Light Sources

    NASA Astrophysics Data System (ADS)

    Gregori, Gianluca

    2013-10-01

    The combination of high power optical lasers and free electron lasers operating at short wavelength (in the x-ray regime) has opened new avenues for laboratory astrophysics, where exotic states of matter can now be generated and probed with high accuracy. We will review a few examples of recent experiments performed at the Linac Coherent Light Source (LCLS) free electron laser operating in Stanford (CA), but also discuss future applications. We will focus our discussion on the following three examples: 1) Laboratory analogues of white dwarf envelopes and the physics of strongly coupled plasmas near crystallization; 2) scaled laboratory experiments to investigate magnetized and radiative shocks; and 3) possible proposals for testing strong gravity analogues using x-ray Thomson scattering. This work was partially the European Research Council under the European Community's Seventh Framework Programme.

  20. Reqscan: An open source solution for laboratory requisition scanning, archiving and retrieval

    PubMed Central

    Bach, Eviatar; Holmes, Daniel T.

    2015-01-01

    Requisition storage and retrieval are an integral part of the outpatient laboratory testing process. It is frequently necessary to review an original requisition to confirm the ordering physician, patient demographics, diagnostic information, and requested tests. Manual retrieval of a paper requisition is time-consuming and tedious. Although commercial solutions exist for the scanning and archiving of barcoded paper requisitions, the tools to accomplish this are freely available from the open source software community. We present a simple dedicated piece of software, Reqscan, for scanning patient laboratory requisitions, finding all barcode information, and saving the requisition as a portable document format named according the barcode(s) found. This Python application offers a simple solution to patient requisition digitization. Reqscan has been successfully tested and implemented into routine practice for storage and retrieval of outpatient requisitions at St. Paul's Hospital, Department of Pathology and Laboratory Medicine in Vancouver, British Columbia, Canada. PMID:25722943

  1. FlowCal: A User-Friendly, Open Source Software Tool for Automatically Converting Flow Cytometry Data from Arbitrary to Calibrated Units.

    PubMed

    Castillo-Hair, Sebastian M; Sexton, John T; Landry, Brian P; Olson, Evan J; Igoshin, Oleg A; Tabor, Jeffrey J

    2016-07-15

    Flow cytometry is widely used to measure gene expression and other molecular biological processes with single cell resolution via fluorescent probes. Flow cytometers output data in arbitrary units (a.u.) that vary with the probe, instrument, and settings. Arbitrary units can be converted to the calibrated unit molecules of equivalent fluorophore (MEF) using commercially available calibration particles. However, there is no convenient, nonproprietary tool available to perform this calibration. Consequently, most researchers report data in a.u., limiting interpretation. Here, we report a software tool named FlowCal to overcome current limitations. FlowCal can be run using an intuitive Microsoft Excel interface, or customizable Python scripts. The software accepts Flow Cytometry Standard (FCS) files as inputs and is compatible with different calibration particles, fluorescent probes, and cell types. Additionally, FlowCal automatically gates data, calculates common statistics, and produces publication quality plots. We validate FlowCal by calibrating a.u. measurements of E. coli expressing superfolder GFP (sfGFP) collected at 10 different detector sensitivity (gain) settings to a single MEF value. Additionally, we reduce day-to-day variability in replicate E. coli sfGFP expression measurements due to instrument drift by 33%, and calibrate S. cerevisiae Venus expression data to MEF units. Finally, we demonstrate a simple method for using FlowCal to calibrate fluorescence units across different cytometers. FlowCal should ease the quantitative analysis of flow cytometry data within and across laboratories and facilitate the adoption of standard fluorescence units in synthetic biology and beyond.

  2. FlowCal: A User-Friendly, Open Source Software Tool for Automatically Converting Flow Cytometry Data from Arbitrary to Calibrated Units.

    PubMed

    Castillo-Hair, Sebastian M; Sexton, John T; Landry, Brian P; Olson, Evan J; Igoshin, Oleg A; Tabor, Jeffrey J

    2016-07-15

    Flow cytometry is widely used to measure gene expression and other molecular biological processes with single cell resolution via fluorescent probes. Flow cytometers output data in arbitrary units (a.u.) that vary with the probe, instrument, and settings. Arbitrary units can be converted to the calibrated unit molecules of equivalent fluorophore (MEF) using commercially available calibration particles. However, there is no convenient, nonproprietary tool available to perform this calibration. Consequently, most researchers report data in a.u., limiting interpretation. Here, we report a software tool named FlowCal to overcome current limitations. FlowCal can be run using an intuitive Microsoft Excel interface, or customizable Python scripts. The software accepts Flow Cytometry Standard (FCS) files as inputs and is compatible with different calibration particles, fluorescent probes, and cell types. Additionally, FlowCal automatically gates data, calculates common statistics, and produces publication quality plots. We validate FlowCal by calibrating a.u. measurements of E. coli expressing superfolder GFP (sfGFP) collected at 10 different detector sensitivity (gain) settings to a single MEF value. Additionally, we reduce day-to-day variability in replicate E. coli sfGFP expression measurements due to instrument drift by 33%, and calibrate S. cerevisiae Venus expression data to MEF units. Finally, we demonstrate a simple method for using FlowCal to calibrate fluorescence units across different cytometers. FlowCal should ease the quantitative analysis of flow cytometry data within and across laboratories and facilitate the adoption of standard fluorescence units in synthetic biology and beyond. PMID:27110723

  3. High Energy Laboratory Astrophysics Experiments using electron beam ion traps and advanced light sources

    NASA Astrophysics Data System (ADS)

    Brown, Gregory V.; Beiersdorfer, Peter; Bernitt, Sven; Eberle, Sita; Hell, Natalie; Kilbourne, Caroline; Kelley, Rich; Leutenegger, Maurice; Porter, F. Scott; Rudolph, Jan; Steinbrugge, Rene; Traebert, Elmar; Crespo-Lopez-Urritia, Jose R.

    2015-08-01

    We have used the Lawrence Livermore National Laboratory's EBIT-I electron beam ion trap coupled with a NASA/GSFC microcalorimeter spectrometer instrument to systematically address problems found in the analysis of high resolution X-ray spectra from celestial sources, and to benchmark atomic physics codes employed by high resolution spectral modeling packages. Our results include laboratory measurements of transition energies, absolute and relative electron impact excitation cross sections, charge exchange cross sections, and dielectronic recombination resonance strengths. More recently, we have coupled to the Max-Plank Institute for Nuclear Physics-Heidelberg's FLASH-EBIT electron beam ion trap to third and fourth generation advanced light sources to measure photoexcitation and photoionization cross sections, as well as, natural line widths of X-ray transitions in highly charged iron ions. Selected results will be presented.

  4. Laboratory source based full-field x-ray microscopy at 9 keV

    NASA Astrophysics Data System (ADS)

    Fella, C.; Balles, A.; Wiest, W.; Zabler, S.; Hanke, R.

    2016-01-01

    In the past decade, hard x-ray transmission microscopy experienced tremendous developments. With the avail-ability of efficient Fresnel zone plates, even set-ups utilizing laboratory sources were developed [1]. In order to improve the performance of these x-ray microscopes, novel approaches to fabricate optical elements [2] and brighter x-ray tubes [3] are promising candidates. We are currently building a laboratory transmission x-ray microscope for 9.25 keV, using an electron impact liquid-metal-jet anode source. Up to now, the further elements of our setup are: a polycapillary condenser, a tungsten zone plate, and a scintillator which is optically coupled to a CMOS camera. However, further variations in terms of optical elements are intended. Here we present the current status of our work, as well as first experimental results.

  5. Laboratory experiments designed to provide limits on the radionuclide source term for the NNWSI Project

    SciTech Connect

    Oversby, V.M.; McCright, R.D.

    1984-11-01

    The Nevada Nuclear Waste Storage Investigations Project is investigating the suitability of the tuffaceous rocks at Yucca Mountain Nevada for potential use as a high-level nuclear waste repository. The horizon under investigation lies above the water table, and therefore offers a setting that differs substantially from other potential repository sites. The unsaturated zone environment allows a simple, but effective, waste package design. The source term for radionuclide release from the waste package will be based on laboratory experiments that determine the corrosion rates and mechanisms for the metal container and the dissolution rate of the waste form under expected long term conditions. This paper describes the present status of laboratory results and outlines the approach to be used in combining the data to develop a realistic source term for release of radionuclides from the waste package. 16 refs., 3 figs., 1 tab.

  6. X-ray phase imaging with a laboratory source using selective reflection from a mirror.

    PubMed

    Pelliccia, Daniele; Paganin, David M

    2013-04-22

    A novel approach for hard x-ray phase contrast imaging with a laboratory source is reported. The technique is based on total external reflection from the edge of a mirror, aligned to intercept only half of the incident beam. The mirror edge thus produces two beams. The refraction x-rays undergo when interacting with a sample placed before the mirror, causes relative intensity variations between direct and reflected beams. Quantitative phase contrast and pure absorption imaging are demonstrated using this method.

  7. MODIS airborne simulator visible and near-infrared calibration, 1991 FIRE-Cirrus field experiment. Calibration version: FIRE King 1.1

    NASA Technical Reports Server (NTRS)

    Arnold, G. Thomas; Fitzgerald, Michael; Grant, Patrick S.; King, Michael D.

    1994-01-01

    Calibration of the visible and near-infrared channels of the MODIS Airborne Simulator (MAS) is derived from observations of a calibrated light source. For the 1991 FIRE-Cirrus field experiment, the calibrated light source was the NASA Goddard 48-inch integrating hemisphere. Laboratory tests during the FIRE Cirrus field experiment were conducted to calibrate the hemisphere and from the hemisphere to the MAS. The purpose of this report is to summarize the FIRE-Cirrus hemisphere calibration, and then describe how the MAS was calibrated from observations of the hemisphere data. All MAS calibration measurements are presented, and determination of the MAS calibration coefficients (raw counts to radiance conversion) is discussed. Thermal sensitivity of the MAS visible and near-infrared calibration is also discussed. Typically, the MAS in-flight is 30 to 60 degrees C colder than the room temperature laboratory calibration. Results from in-flight temperature measurements and tests of the MAS in a cold chamber are given, and from these, equations are derived to adjust the MAS in-flight data to what the value would be at laboratory conditions. For FIRE-Cirrus data, only channels 3 through 6 were found to be temperature sensitive. The final section of this report describes comparisons to an independent MAS (room temperature) calibration by Ames personnel using their 30-inch integrating sphere.

  8. An External Matrix-Assisted Laser Desorption Ionization Source for Flexible FT-ICR Mass Spectrometry Imaging with Internal Calibration on Adjacent Samples

    NASA Astrophysics Data System (ADS)

    Smith, Donald F.; Aizikov, Konstantin; Duursma, Marc C.; Giskes, Frans; Spaanderman, Dirk-Jan; McDonnell, Liam A.; O'Connor, Peter B.; Heeren, Ron M. A.

    2011-01-01

    We describe the construction and application of a new MALDI source for FT-ICR mass spectrometry imaging. The source includes a translational X-Y positioning stage with a 10 × 10 cm range of motion for analysis of large sample areas, a quadrupole for mass selection, and an external octopole ion trap with electrodes for the application of an axial potential gradient for controlled ion ejection. An off-line LC MALDI MS/MS run demonstrates the utility of the new source for data- and position-dependent experiments. A FT-ICR MS imaging experiment of a coronal rat brain section yields ˜200 unique peaks from m/z 400-1100 with corresponding mass-selected images. Mass spectra from every pixel are internally calibrated with respect to polymer calibrants collected from an adjacent slide.

  9. SQUID (Superconducting Quantum Interference Device) arrays for simultaneous magnetic measurements: calibration and source localization performance. Report for September 1986-February 1988

    SciTech Connect

    Kaufman, L.; Williamson, S.J.; Costa Ribeiro, P.

    1988-02-29

    Recently developed small arrays of SQUID-based magnetic sensors can, if appropriately placed, locate the position of a confined biomagnetic source without moving the array. The authors present a technique with a relative accuracy of about 2% for calibrating such sensors having detection coils with the geometry of a second-order gradiometer. The effects of calibration error and magnetic noise on the accuracy of locating an equivalent current dipole source in the human brain are investigated for 5- and 7-sensor probes and for a pair of 7-sensor probes. With a noise level of 5% of peak signal, uncertainties of about 20% in source strength and depth for a 5-sensor probe are reduced to 8% for a pair of 7-sensor probes, and uncertainties of about 15 mm in lateral position are reduced to 1 mm, for the configuration considered.

  10. A Simple LIBS (Laser-Induced Breakdown Spectroscopy) Laboratory Experiment to Introduce Undergraduates to Calibration Functions and Atomic Spectroscopy

    ERIC Educational Resources Information Center

    Chinni, Rosemarie C.

    2012-01-01

    This laboratory experiment introduces students to a different type of atomic spectroscopy: laser-induced breakdown spectroscopy (LIBS). LIBS uses a laser-generated spark to excite the sample; once excited, the elemental emission is spectrally resolved and detected. The students use LIBS to analyze a series of standard synthetic silicate samples…

  11. Cross calibration of new x-ray films against direct exposure film from 1 to 8 keV using the X-pinch x-ray source

    NASA Astrophysics Data System (ADS)

    Chandler, K. M.; Pikuz, S. A.; Shelkovenko, T. A.; Mitchell, M. D.; Hammer, D. A.; Knauer, J. P.

    2005-11-01

    A cross calibration of readily available x-ray sensitive films has been carried out against the calibrated direct exposure film (DEF) which is no longer being manufactured by Kodak. Four-wire X pinches made from various metal wires were used as x-ray sources for this purpose. Tests were carried out for the Kodak films Biomax MS, Biomax XAR, M100, Technical Pan, and T-Max over the energy range of 1-8keV (12.4-1.5Å wavelength). The same hand-development procedures as described by Henke et al. [J. Opt. Soc. Am. B 3, 1540 (1986)] were followed for all films in every test. Sensitivity curves as a function of wavelength for these films relative DEF are presented. These relative calibrations show that Biomax MS is likely to be the best replacement film for DEF for most purposes over the energy range tested here.

  12. Effect of numerical dispersion as a source of structural noise in the calibration of a highly parameterized saltwater intrusion model

    USGS Publications Warehouse

    Langevin, Christian D.; Hughes, Joseph D.

    2010-01-01

    A model with a small amount of numerical dispersion was used to represent saltwater 7 intrusion in a homogeneous aquifer for a 10-year historical calibration period with one 8 groundwater withdrawal location followed by a 10-year prediction period with two groundwater 9 withdrawal locations. Time-varying groundwater concentrations at arbitrary locations in this low-10 dispersion model were then used as observations to calibrate a model with a greater amount of 11 numerical dispersion. The low-dispersion model was solved using a Total Variation Diminishing 12 numerical scheme; an implicit finite difference scheme with upstream weighting was used for 13 the calibration simulations. Calibration focused on estimating a three-dimensional hydraulic 14 conductivity field that was parameterized using a regular grid of pilot points in each layer and a 15 smoothness constraint. Other model parameters (dispersivity, porosity, recharge, etc.) were 16 fixed at the known values. The discrepancy between observed and simulated concentrations 17 (due solely to numerical dispersion) was reduced by adjusting hydraulic conductivity through the 18 calibration process. Within the transition zone, hydraulic conductivity tended to be lower than 19 the true value for the calibration runs tested. The calibration process introduced lower hydraulic 20 conductivity values to compensate for numerical dispersion and improve the match between 21 observed and simulated concentration breakthrough curves at monitoring locations. 22 Concentrations were underpredicted at both groundwater withdrawal locations during the 10-23 year prediction period.

  13. Comparison of Spectral Radiance Calibration Techniques Used for Backscatter Ultraviolet Satellite Instruments

    NASA Technical Reports Server (NTRS)

    Kowalewski, Matthew G.; Janz, Scott

    2014-01-01

    Methods for determining the absolute radiometric calibration sensitivities of backscatter ultraviolet (BUV) satellite instruments are compared as part of an effort to minimize pre-launch calibration errors. An internally illuminated integrating sphere source has been used for the Shuttle Solar BUV (SSBUV), Total Ozone Mapping Spectrometer (TOMS), Ozone Mapping Instrument (OMI), and Global Ozone Monitoring Experiment 2 (GOME-2) using standardized procedures traceable to national standards. These sphere-based sensitivities agree to within three percent [k equals 2] relative to calibrations performed using an external diffuser illuminated by standard irradiance sources, the customary radiance calibration method for BUV instruments. The uncertainty for these calibration techniques as implemented at the NASA Goddard Space Flight Centers Radiometric Calibration and Development Laboratory is shown to be 4 percent at 250nm [k equals 2] when using a single traceable calibration standard. Significant reduction in the uncertainty of nearly 1 percent is demonstrated when multiple calibration standards are used.

  14. Users program for storage-ring based FEL and synchrotron sources of the Duke FEL Laboratory

    SciTech Connect

    Straub, K.D.; Barnett, G.; Burnham, B.

    1995-12-31

    The storage ring at the Duke FEL Laboratory was first operated with a stored e-beam in November, 1994. It has now achieved operation energies in excess 1 GeV with more than 100 mA current at 280 MeV. The ring has several ports for FEL and synchrotron light source research. The circulating ring current can be synchronized with the seperate Mark III FEL operating in the 2-9.5 {mu}m IR region. This allows low optical jitter (10-20 ps) between the two sources and thus pump-probe operation. The ring has been configured to drive a number of light sources including the OK-4 FEL system capable of FEL operation between 400 and 65 nm, an inverse Compton scattering source using this undulator which will yield 4-200 MeV gammas, an undulator source at approximately 40 {angstrom} (not an FEL), a mm FEL with inverse compton scattering providing 1-100 keV x-rays and two synchrotron ports from the bend magnets for which the {lambda}{sub c} = 11-12 {angstrom} for 1 GeV. The broadly tunable FEL sources and their associated inverse compton scattering are extremely bright. The initial research proposals, submitted to the Laboratory emphasizes photoelectron spectroscopy, PEEM, high resolution vacuum UV of gases, solid spectroscopy and photochemistry in the UV, X-ray microprobe studies, X-ray microscopy, X-ray holography, X-ray crystallography, Mossbauer spectroscopy, nuclear spectroscopy, neutron production, photon activation therapy and broadband synchrotron as a probe of fast reaction in the IR and near IR.

  15. POLCAL - POLARIMETRIC RADAR CALIBRATION

    NASA Technical Reports Server (NTRS)

    Vanzyl, J.

    1994-01-01

    Calibration of polarimetric radar systems is a field of research in which great progress has been made over the last few years. POLCAL (Polarimetric Radar Calibration) is a software tool intended to assist in the calibration of Synthetic Aperture Radar (SAR) systems. In particular, POLCAL calibrates Stokes matrix format data produced as the standard product by the NASA/Jet Propulsion Laboratory (JPL) airborne imaging synthetic aperture radar (AIRSAR). POLCAL was designed to be used in conjunction with data collected by the NASA/JPL AIRSAR system. AIRSAR is a multifrequency (6 cm, 24 cm, and 68 cm wavelength), fully polarimetric SAR system which produces 12 x 12 km imagery at 10 m resolution. AIRSTAR was designed as a testbed for NASA's Spaceborne Imaging Radar program. While the images produced after 1991 are thought to be calibrated (phase calibrated, cross-talk removed, channel imbalance removed, and absolutely calibrated), POLCAL can and should still be used to check the accuracy of the calibration and to correct it if necessary. Version 4.0 of POLCAL is an upgrade of POLCAL version 2.0 released to AIRSAR investigators in June, 1990. New options in version 4.0 include automatic absolute calibration of 89/90 data, distributed target analysis, calibration of nearby scenes with calibration parameters from a scene with corner reflectors, altitude or roll angle corrections, and calibration of errors introduced by known topography. Many sources of error can lead to false conclusions about the nature of scatterers on the surface. Errors in the phase relationship between polarization channels result in incorrect synthesis of polarization states. Cross-talk, caused by imperfections in the radar antenna itself, can also lead to error. POLCAL reduces cross-talk and corrects phase calibration without the use of ground calibration equipment. Removing the antenna patterns during SAR processing also forms a very important part of the calibration of SAR data. Errors in the

  16. Calibration of a helium-cooled infrared spatial radiometer and grating spectrometer

    NASA Technical Reports Server (NTRS)

    Jacobsen, Larry; Sargent, Steve; Wyatt, Clair L.; Steed, Allan J.

    1992-01-01

    Methods used by the Space Dynamics Laboratory of Utah State University (SDL/USU) to calibrate infrared sensors are described, using the Infrared Background Signature Survey (IBSS) spatial radiometer and grating spectrometer as examples. A calibration equation and a radiometric model are given for each sensor to describe their responsivity in terms of individual radiometric parameters. The calibration equation terms include dark offset, linearity, absolute responsivity, and measurement uncertainty, and the radiometric model domains include spatial, spectral, and temporal domains. A portable calibration facility, designed and fabricated by SDL/USU, provided collimated, extended, diffuse scatter, and Jones sources in a single cryogenic dewar. This multi-function calibrator allowed calibration personnel to complete a full calibration of the IBSS infrared radiometer and spectrometer in two 15-day periods. A calibration data system was developed to control and monitor the calibration facility, and to record and analyze sensor data.

  17. Report on key comparison COOMET.AUV.A-K5: pressure calibration of laboratory standard microphones in the frequency range 2 Hz to 10 kHz

    NASA Astrophysics Data System (ADS)

    Dobrowolska, D.; Kosterov, A.

    2016-01-01

    This is the final report for regional key comparison COOMET.AUV.A-K5 on the pressure calibration of laboratory standard microphones in the frequency range from 2 Hz to 10 kHz. Two laboratories—Central Office of Measures (GUM)—the national metrology institute for Poland and the State Enterprise Scientific-Research Institute for Metrology of Measurement and Control Systems (DP NDI Systema)— the designated institute for acoustics in Ukraine took part in this comparison with the GUM as a pilot. One travelling type LS1P microphone was circulated to the participants and results in the form of regular calibration certificates were collected. The results of the DP NDI Systema obtained in this comparison were linked to the CCAUV.A-K5 key comparison through the joint participation of the GUM. The degrees of equivalence were computed for DP NDI Systema with respect to the CCAUV.A-K5 key comparison reference value. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCAUV, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  18. BROOKHAVEN NATIONAL LABORATORY SOURCE WATER ASSESSMENT FOR DRINKING WATER SUPPLY WELLS

    SciTech Connect

    BENNETT,D.B.; PAQUETTE,D.E.; KLAUS,K.; DORSCH,W.R.

    2000-12-18

    The BNL water supply system meets all water quality standards and has sufficient pumping and storage capacity to meet current and anticipated future operational demands. Because BNL's water supply is drawn from the shallow Upper Glacial aquifer, BNL's source water is susceptible to contamination. The quality of the water supply is being protected through (1) a comprehensive program of engineered and operational controls of existing aquifer contamination and potential sources of new contamination, (2) groundwater monitoring, and (3) potable water treatment. The BNL Source Water Assessment found that the source water for BNL's Western Well Field (comprised of Supply Wells 4, 6, and 7) has relatively few threats of contamination and identified potential sources are already being carefully managed. The source water for BNL's Eastern Well Field (comprised of Supply Wells 10, 11, and 12) has a moderate number of threats to water quality, primarily from several existing volatile organic compound and tritium plumes. The g-2 Tritium Plume and portions of the Operable Unit III VOC plume fall within the delineated source water area for the Eastern Well Field. In addition, portions of the much slower migrating strontium-90 plumes associated with the Brookhaven Graphite Research Reactor, Waste Concentration Facility and Building 650 lie within the Eastern source water area. However, the rate of travel in the aquifer for strontium-90 is about one-twentieth of that for tritium and volatile organic compounds. The Laboratory has been carefully monitoring plume migration, and has made adjustments to water supply operations. Although a number of BNL's water supply wells were impacted by VOC contamination in the late 1980s, recent routine analysis of water samples from BNL's supply wells indicate that no drinking water standards have been reached or exceeded. The high quality of the water supply strongly indicates that the operational and engineered controls implemented over the past

  19. Integrated Verification Experiment data collected as part of the Los Alamos National Laboratory`s Source Region Program. Appendix B: Surface ground motion

    SciTech Connect

    Weaver, T.A.; Baker, D.F.; Edwards, C.L.; Freeman, S.H.

    1993-10-01

    Surface ground motion was recorded for many of the Integrated Verification Experiments using standard 10-, 25- and 100-g accelerometers, force-balanced accelerometers and, for some events, using golf balls and 0.39-cm steel balls as surface inertial gauges (SIGs). This report contains the semi-processed acceleration, velocity, and displacement data for the accelerometers fielded and the individual observations for the SIG experiments. Most acceleration, velocity, and displacement records have had calibrations applied and have been deramped, offset corrected, and deglitched but are otherwise unfiltered or processed from their original records. Digital data for all of these records are stored at Los Alamos National Laboratory.

  20. Recommendations following a multi-laboratory comparison of microbial source tracking methods.

    PubMed

    Stewart, Jill R; Boehm, Alexandria B; Dubinsky, Eric A; Fong, Theng-Theng; Goodwin, Kelly D; Griffith, John F; Noble, Rachel T; Shanks, Orin C; Vijayavel, Kannappan; Weisberg, Stephen B

    2013-11-15

    Microbial source tracking (MST) methods were evaluated in the Source Identification Protocol Project (SIPP), in which 27 laboratories compared methods to identify host sources of fecal pollution from blinded water samples containing either one or two different fecal types collected from California. This paper details lessons learned from the SIPP study and makes recommendations to further advance the field of MST. Overall, results from the SIPP study demonstrated that methods are available that can correctly identify whether particular host sources including humans, cows and birds have contributed to contamination in a body of water. However, differences between laboratory protocols and data processing affected results and complicated interpretation of MST method performance in some cases. This was an issue particularly for samples that tested positive (non-zero Ct values) but below the limits of quantification or detection of a PCR assay. Although false positives were observed, such samples in the SIPP study often contained the fecal pollution source that was being targeted, i.e., the samples were true positives. Given these results, and the fact that MST often requires detection of targets present in low concentrations, we propose that such samples be reported and identified in a unique category to facilitate data analysis and method comparisons. Important data can be lost when such samples are simply reported as positive or negative. Actionable thresholds were not derived in the SIPP study due to limitations that included geographic scope, age of samples, and difficulties interpreting low concentrations of target in environmental samples. Nevertheless, the results of the study support the use of MST for water management, especially to prioritize impaired waters in need of remediation. Future integration of MST data into quantitative microbial risk assessments and other models could allow managers to more efficiently protect public health based on site conditions

  1. Recommendations following a multi-laboratory comparison of microbial source tracking methods.

    PubMed

    Stewart, Jill R; Boehm, Alexandria B; Dubinsky, Eric A; Fong, Theng-Theng; Goodwin, Kelly D; Griffith, John F; Noble, Rachel T; Shanks, Orin C; Vijayavel, Kannappan; Weisberg, Stephen B

    2013-11-15

    Microbial source tracking (MST) methods were evaluated in the Source Identification Protocol Project (SIPP), in which 27 laboratories compared methods to identify host sources of fecal pollution from blinded water samples containing either one or two different fecal types collected from California. This paper details lessons learned from the SIPP study and makes recommendations to further advance the field of MST. Overall, results from the SIPP study demonstrated that methods are available that can correctly identify whether particular host sources including humans, cows and birds have contributed to contamination in a body of water. However, differences between laboratory protocols and data processing affected results and complicated interpretation of MST method performance in some cases. This was an issue particularly for samples that tested positive (non-zero Ct values) but below the limits of quantification or detection of a PCR assay. Although false positives were observed, such samples in the SIPP study often contained the fecal pollution source that was being targeted, i.e., the samples were true positives. Given these results, and the fact that MST often requires detection of targets present in low concentrations, we propose that such samples be reported and identified in a unique category to facilitate data analysis and method comparisons. Important data can be lost when such samples are simply reported as positive or negative. Actionable thresholds were not derived in the SIPP study due to limitations that included geographic scope, age of samples, and difficulties interpreting low concentrations of target in environmental samples. Nevertheless, the results of the study support the use of MST for water management, especially to prioritize impaired waters in need of remediation. Future integration of MST data into quantitative microbial risk assessments and other models could allow managers to more efficiently protect public health based on site conditions.

  2. Performance of viruses and bacteriophages for fecal source determination in a multi-laboratory, comparative study.

    PubMed

    Harwood, Valerie J; Boehm, Alexandria B; Sassoubre, Lauren M; Vijayavel, Kannappan; Stewart, Jill R; Fong, Theng-Theng; Caprais, Marie-Paule; Converse, Reagan R; Diston, David; Ebdon, James; Fuhrman, Jed A; Gourmelon, Michele; Gentry-Shields, Jennifer; Griffith, John F; Kashian, Donna R; Noble, Rachel T; Taylor, Huw; Wicki, Melanie

    2013-11-15

    An inter-laboratory study of the accuracy of microbial source tracking (MST) methods was conducted using challenge fecal and sewage samples that were spiked into artificial freshwater and provided as unknowns (blind test samples) to the laboratories. The results of the Source Identification Protocol Project (SIPP) are presented in a series of papers that cover 41 MST methods. This contribution details the results of the virus and bacteriophage methods targeting human fecal or sewage contamination. Human viruses used as source identifiers included adenoviruses (HAdV), enteroviruses (EV), norovirus Groups I and II (NoVI and NoVII), and polyomaviruses (HPyVs). Bacteriophages were also employed, including somatic coliphages and F-specific RNA bacteriophages (FRNAPH) as general indicators of fecal contamination. Bacteriophage methods targeting human fecal sources included genotyping of FRNAPH isolates and plaque formation on bacterial hosts Enterococcus faecium MB-55, Bacteroides HB-73 and Bacteroides GB-124. The use of small sample volumes (≤50 ml) resulted in relatively insensitive theoretical limits of detection (10-50 gene copies or plaques × 50 ml(-1)) which, coupled with low virus concentrations in samples, resulted in high false-negative rates, low sensitivity, and low negative predictive values. On the other hand, the specificity of the human virus methods was generally close to 100% and positive predictive values were ∼40-70% with the exception of NoVs, which were not detected. The bacteriophage methods were generally much less specific toward human sewage than virus methods, although FRNAPH II genotyping was relatively successful, with 18% sensitivity and 85% specificity. While the specificity of the human virus methods engenders great confidence in a positive result, better concentration methods and larger sample volumes must be utilized for greater accuracy of negative results, i.e. the prediction that a human contamination source is absent.

  3. Vibration considerations in the design of the Advanced Photon Source at Argonne National Laboratory

    SciTech Connect

    Jendrzejczyk, J.A.; Wambsganss, M.W.

    1991-01-01

    The Advanced Photon Source (APS), a new synchrotron radiation facility being built at Argonne National Laboratory, will provide the world's most brilliant X-ray beams for research in a wide range of technical fields. Successful operation of the APS requires an extremely stable positron closed orbit. Vibration of the storage ring quadrupole magnets, even in the submicron range, can lead to distortion of the positron closed orbit and to potentially unacceptable beam emittance growth, which results in degraded performance. This paper presents an overview of the technical approach used to minimize vibration response, beginning at the conceptual stage, through design and construction, and on to successful operation. Acceptance criteria relating to maximum allowable quadrupole magnet vibration are discussed. Soil properties are used to determine resonant frequencies of foundations and to predict attenuation characteristics. Two sources are considered to have the potential to excite the foundation: far-field sources, which are produced external to the facility, and near-field sources, which are produced within the facility. Measurements of ambient ground motion, monitored to determine far- field excitation, are presented. Ambient vibration was measured at several operating facilities within Argonne to gain insight on typical near-field excitation sources. Discussion covers the dynamic response characteristics of a prototypic magnet support structure to various excitations, including ambient floor motion, coolant flow, and magnet power. 19 refs., 10 figs., 5 tabs.

  4. Laboratory Calibration Studies in Support of ORGANICS on the International Space Station: Evolution of Organic Matter in Space

    NASA Technical Reports Server (NTRS)

    Ruiterkamp, R.; Ehrenfreund, P.; Halasinski, T.; Salama, F.; Foing, B.; Schmidt, W.

    2002-01-01

    This paper describes the scientific overview and current status of ORGANICS an exposure experiment performed on the International Space Station (ISS) to study the evolution of organic matter in space (PI: P. Ehrenfreund), with supporting laboratory experiments performed at NASA Ames. ORGANICS investigates the chemical evolution of samples submitted to long-duration exposure to space environment in near-Earth orbit. This experiment will provide information on the nature, evolution, and survival of carbon species in the interstellar medium (ISM) and in solar system targets.

  5. Calibration of hydrometers

    NASA Astrophysics Data System (ADS)

    Lorefice, Salvatore; Malengo, Andrea

    2006-10-01

    After a brief description of the different methods employed in periodic calibration of hydrometers used in most cases to measure the density of liquids in the range between 500 kg m-3 and 2000 kg m-3, particular emphasis is given to the multipoint procedure based on hydrostatic weighing, known as well as Cuckow's method. The features of the calibration apparatus and the procedure used at the INRiM (formerly IMGC-CNR) density laboratory have been considered to assess all relevant contributions involved in the calibration of different kinds of hydrometers. The uncertainty is strongly dependent on the kind of hydrometer; in particular, the results highlight the importance of the density of the reference buoyant liquid, the temperature of calibration and the skill of operator in the reading of the scale in the whole assessment of the uncertainty. It is also interesting to realize that for high-resolution hydrometers (division of 0.1 kg m-3), the uncertainty contribution of the density of the reference liquid is the main source of the total uncertainty, but its importance falls under about 50% for hydrometers with a division of 0.5 kg m-3 and becomes somewhat negligible for hydrometers with a division of 1 kg m-3, for which the reading uncertainty is the predominant part of the total uncertainty. At present the best INRiM result is obtained with commercially available hydrometers having a scale division of 0.1 kg m-3, for which the relative uncertainty is about 12 × 10-6.

  6. Imager for Mars Pathfinder (IMP) image calibration

    USGS Publications Warehouse

    Reid, R.J.; Smith, P.H.; Lemmon, M.; Tanner, R.; Burkland, M.; Wegryn, E.; Weinberg, J.; Marcialis, R.; Britt, D.T.; Thomas, N.; Kramm, R.; Dummel, A.; Crowe, D.; Bos, B.J.; Bell, J.F.; Rueffer, P.; Gliem, F.; Johnson, J. R.; Maki, J.N.; Herkenhoff, K. E.; Singer, Robert B.

    1999-01-01

    The Imager for Mars Pathfinder returned over 16,000 high-quality images from the surface of Mars. The camera was well-calibrated in the laboratory, with <5% radiometric uncertainty. The photometric properties of two radiometric targets were also measured with 3% uncertainty. Several data sets acquired during the cruise and on Mars confirm that the system operated nominally throughout the course of the mission. Image calibration algorithms were developed for landed operations to correct instrumental sources of noise and to calibrate images relative to observations of the radiometric targets. The uncertainties associated with these algorithms as well as current improvements to image calibration are discussed. Copyright 1999 by the American Geophysical Union.

  7. Automated calibration of a flight particle spectrometer

    NASA Technical Reports Server (NTRS)

    Torbert, Roy B.

    1986-01-01

    An automatic calibration system was designed for use in the vacuum facility at the Space Science Laboratory of the Marshall Space Flight Center. That system was developed and used in the intervening winter to calibrate the ion spectrometer that eventually flew in May 1986 aboard the NASA project, CRIT 1. During this summer, it is planned to implement the calibration of both an ion and electron spectrometer of a new design whose basic elements were conceived during the winter of 1985 to 1986. This spectrometer was completed in the summer and successfully mounted in the vacuum tank for calibration. However, the source gate valve malfunctioned, and, at the end of the summer, it still needed a replacement. During the inevitable delays in the experimental research, the numerical model of the Critical Velocity effect was completed and these results were presented.

  8. Measurement of Turbulence with Acoustic Doppler Current Profilers - Sources of Error and Laboratory Results

    USGS Publications Warehouse

    Nystrom, E.A.; Oberg, K.A.; Rehmann, C.R.; ,

    2002-01-01

    Acoustic Doppler current profilers (ADCPs) provide a promising method for measuring surface-water turbulence because they can provide data from a large spatial range in a relatively short time with relative ease. Some potential sources of errors in turbulence measurements made with ADCPs include inaccuracy of Doppler-shift measurements, poor temporal and spatial measurement resolution, and inaccuracy of multi-dimensional velocities resolved from one-dimensional velocities measured at separate locations. Results from laboratory measurements of mean velocity and turbulence statistics made with two pulse-coherent ADCPs in 0.87 meters of water are used to illustrate several of inherent sources of error in ADCP turbulence measurements. Results show that processing algorithms and beam configurations have important effects on turbulence measurements. ADCPs can provide reasonable estimates of many turbulence parameters; however, the accuracy of turbulence measurements made with commercially available ADCPs is often poor in comparison to standard measurement techniques.

  9. Coseismic offsets recorded by borehole strainmeters from the 2014, Mw 6.0 South Napa, California earthquake: Reconciling tidal calibrations with earthquake source models.

    NASA Astrophysics Data System (ADS)

    Langbein, J. O.

    2015-12-01

    The 24 August 2014 Mw 6.0 South Napa, California earthquake produced significant offsets on 12 borehole strainmeters in the San Francisco Bay area. These strainmeters are located between 24 and 80 km from the source and the observed offsets ranged up to 400 parts-per-billion (ppb), which exceeds their nominal precision by a factor of 100. However, the observed offsets in tidally-calibrated strains have RMS deviation of 130 ppb from strains predicted by previously published moment tensor derived from seismic data. Here, I show that the large misfit can be reduced by a combination of better tidal calibration and better modeling of the strain field from the earthquake. Borehole strainmeters require in-situ calibration, which historically has been accomplished by comparing their measurements of Earth tides with the strain-tides predicted by a model. Although borehole strainmeters accurately measure the deformation within the borehole, the long-wavelength strain signals from tides or other tectonic processes recorded in the borehole are modified by the presence of the borehole and the elastic properties of the grout and the instrument. Previous analyses of surface-mounted, strainmeter data and their relationship with the predicted tides suggest that tidal models could be in error by 30%. The poor fit of the borehole strainmeter data from this earthquake can be improved by simultaneously varying the components of the model tides up to 30% and making small adjustments to the point-source model of the earthquake, which reduces the RMS misfit from 130 to 18 ppb. This suggests that calibrations derived solely from tidal models limits the accuracy of borehole strainmeters. On the other hand, the revised calibration derived here becomes testable on strain measurements from future, large Bay area events.

  10. New approach for the radiometric calibration of spectral imaging systems.

    PubMed

    Kohler, David; Bissett, W; Steward, Robert; Davis, Curtiss

    2004-05-31

    The calibration of multispectral and hyperspectral imaging systems is typically done in the laboratory using an integrating sphere, which usually produces a signal that is red rich. Using such a source to calibrate environmental monitoring systems presents some difficulties. Not only is much of the calibration data outside the range and spectral quality of data values that are expected to be captured in the field, using these measurements alone may exaggerate the optical flaws found within the system. Left unaccounted for, these flaws will become embedded in to the calibration, and thus, they will be passed on to the field data when the calibration is applied. To address these issues, we used a series of well-characterized spectral filters within our calibration. It provided us with a set us stable spectral standards to test and account for inadequacies in the spectral and radiometric integrity of the optical imager.

  11. Recovery the release history and source location of a pollutant in groundwater using data collected in laboratory

    NASA Astrophysics Data System (ADS)

    Zanini, A.; Cupola, F.

    2013-12-01

    This work shows the application of an innovative procedure that is able to simultaneously identify the release history and the source location of a pollutant injection in groundwater using a dataset obtained experimentally. The methodology follows a geostatistical approach and it requires a preliminary delineation of a probably source area. The dataset was provided through an experimental installation developed at the hydraulic laboratory of the University of Parma (DICATeA). The equipment represents a 2-D unconfined aquifer controlled through two constant head levels (upstream and downstream); it consists of a Plexiglas sandbox filled with a porous medium (1 mm glass beads). An injector was placed inside the porous medium and sodium fluorescein salt was used as tracer during the tests. The standard test consists of releasing a constant and known concentration with a variable flow rate. The injection rate and the mean flow rate inside the sandbox are stored by means of a data acquisition system, meanwhile the concentration distribution inside the sandbox is observed through the processing of side wall images collected by means of a digital camera. The digital camera and the sandbox are placed in a dark room lightened by blue light in order to excite the fluorescein and easily evaluate the concentration distribution. A Matlab routine was developed to cut and to correct images by a projective transformation in order to obtain pictures with same size and orientation. Each pixel of the image has known coordinates on the sandbox. After a calibration process, the relationships between the luminosity of the emitted fluorescence and the tracer concentration have been identified in each pixel of the picture and consequently in each point of the domain. Initially a series of simple tests (with constant injection) were carried out with the aim at validating the experimental equipment comparing the observed data to those collected through the images, such as mass balance or

  12. Laboratory calibration and field testing of the Chemcatcher-Metal for trace levels of rare earth elements in estuarine waters.

    PubMed

    Petersen, Jördis; Pröfrock, Daniel; Paschke, Albrecht; Broekaert, Jose A C; Prange, Andreas

    2015-10-01

    Little knowledge is available about water concentrations of rare earth elements (REEs) in the marine environment. The direct measurement of REEs in coastal waters is a challenging task due to their ultra-low concentrations as well as the high salt content in the water samples. To quantify these elements at environmental concentrations (pg L(-1) to low ng L(-1)) in coastal waters, current analytical techniques are generally expensive and time consuming, and require complex chemical preconcentration procedures. Therefore, an integrative passive sampler was tested as a more economic alternative sampling approach for REE analysis. We used a Chemcatcher-Metal passive sampler consisting of a 3M Empore Chelating Disk as the receiving phase, as well as a cellulose acetate membrane as the diffusion-limiting layer. The effect of water turbulence and temperature on the uptake rates of REEs was analyzed during 14-day calibration experiments by a flow-through exposure tank system. The sampling rates were in the range of 0.42 mL h(-1) (13 °C; 0.25 m s(-1)) to 4.01 mL h(-1) (13 °C; 1 m s(-1)). Similar results were obtained for the different REEs under investigation. The water turbulence was the most important influence on uptake. The uptake rates were appropriate to ascertain time-weighted average concentrations of REEs during a field experiment in the Elbe Estuary near Cuxhaven Harbor (exposure time 4 weeks). REE concentrations were determined to be in the range 0.2 to 13.8 ng L(-1), where the highest concentrations were found for neodymium and samarium. In comparison, most of the spot samples measured along the Chemcatcher samples had REE concentrations below the limit of detection, in particular due to necessary dilution to minimize the analytical problems that arise with the high salt content in marine water samples. This study was among the first efforts to measure REE levels in the field using a passive sampling approach. Our results suggest that passive samplers could be

  13. 3D nanoscale imaging of biological samples with laboratory-based soft X-ray sources

    NASA Astrophysics Data System (ADS)

    Dehlinger, Aurélie; Blechschmidt, Anne; Grötzsch, Daniel; Jung, Robert; Kanngießer, Birgit; Seim, Christian; Stiel, Holger

    2015-09-01

    In microscopy, where the theoretical resolution limit depends on the wavelength of the probing light, radiation in the soft X-ray regime can be used to analyze samples that cannot be resolved with visible light microscopes. In the case of soft X-ray microscopy in the water-window, the energy range of the radiation lies between the absorption edges of carbon (at 284 eV, 4.36 nm) and oxygen (543 eV, 2.34 nm). As a result, carbon-based structures, such as biological samples, posses a strong absorption, whereas e.g. water is more transparent to this radiation. Microscopy in the water-window, therefore, allows the structural investigation of aqueous samples with resolutions of a few tens of nanometers and a penetration depth of up to 10μm. The development of highly brilliant laser-produced plasma-sources has enabled the transfer of Xray microscopy, that was formerly bound to synchrotron sources, to the laboratory, which opens the access of this method to a broader scientific community. The Laboratory Transmission X-ray Microscope at the Berlin Laboratory for innovative X-ray technologies (BLiX) runs with a laser produced nitrogen plasma that emits radiation in the soft X-ray regime. The mentioned high penetration depth can be exploited to analyze biological samples in their natural state and with several projection angles. The obtained tomogram is the key to a more precise and global analysis of samples originating from various fields of life science.

  14. The EnzymeTracker: an open-source laboratory information management system for sample tracking

    PubMed Central

    2012-01-01

    Background In many laboratories, researchers store experimental data on their own workstation using spreadsheets. However, this approach poses a number of problems, ranging from sharing issues to inefficient data-mining. Standard spreadsheets are also error-prone, as data do not undergo any validation process. To overcome spreadsheets inherent limitations, a number of proprietary systems have been developed, which laboratories need to pay expensive license fees for. Those costs are usually prohibitive for most laboratories and prevent scientists from benefiting from more sophisticated data management systems. Results In this paper, we propose the EnzymeTracker, a web-based laboratory information management system for sample tracking, as an open-source and flexible alternative that aims at facilitating entry, mining and sharing of experimental biological data. The EnzymeTracker features online spreadsheets and tools for monitoring numerous experiments conducted by several collaborators to identify and characterize samples. It also provides libraries of shared data such as protocols, and administration tools for data access control using OpenID and user/team management. Our system relies on a database management system for efficient data indexing and management and a user-friendly AJAX interface that can be accessed over the Internet. The EnzymeTracker facilitates data entry by dynamically suggesting entries and providing smart data-mining tools to effectively retrieve data. Our system features a number of tools to visualize and annotate experimental data, and export highly customizable reports. It also supports QR matrix barcoding to facilitate sample tracking. Conclusions The EnzymeTracker was designed to be easy to use and offers many benefits over spreadsheets, thus presenting the characteristics required to facilitate acceptance by the scientific community. It has been successfully used for 20 months on a daily basis by over 50 scientists. The EnzymeTracker is

  15. Remediation of DNAPL source zones with granular iron: laboratory and field tests.

    PubMed

    Wadley, Sharon L S; Gillham, Robert W; Gui, Lai

    2005-01-01

    Degradation of dissolved chlorinated solvents using granular iron is an established in situ technology. This paper reports on investigations into mixing iron and bentonite with contaminated soil for in situ containment and degradation of dense nonaqueous phase liquid source zones. In the laboratory, hypovials containing soil, water, bentonite, iron, and free-phase trichloroethene (TCE) were assembled. Periodic measurement of TCE, chloride, and degradation products showed progressive degradation of TCE to nondetectable levels. Subsequently, a demonstration was conducted at Canadian Forces Base Borden near Alliston, Ontario, Canada, where, in 1991, a portion of the surficial aquifer was isolated and free-phase tetrachloroethene (PCE) was introduced. Using a drill rig equipped with large-diameter mixing blades, three mixed zones were prepared containing 0%, 5%, and 10% granular iron by volume. The bentonite was added to serve as a lubricant to facilitate injection of the iron and to isolate the contaminated zone. Analysis of core samples showed reasonably uniform distributions of iron through the mixed zones. Monitoring over a 13-month period following installation showed, relative to the control, a decline in PCE concentrations to virtually nondetectable values. Reaction rates in the laboratory tests were similar to those reported in the literature, while the rate in the field test was substantially lower. The lower rate may be a consequence of mass transfer limitations under the static conditions of the field test. Results indicate that mixing iron and bentonite into source zones may be an effective means of source-zone remediation, with the particular advantage of being relatively immune to effects of geologic heterogeneity.

  16. Real-time dynamic calibration of a tunable frequency laser source using a Fabry-Pérot interferometer

    SciTech Connect

    Mandula, Gábor Kis, Zsolt; Lengyel, Krisztián

    2015-12-15

    We report on a method for real-time dynamic calibration of a tunable external cavity diode laser by using a partially mode-matched plano-concave Fabry-Pérot interferometer in reflection geometry. Wide range laser frequency scanning is carried out by piezo-driven tilting of a diffractive grating playing the role of a frequency selective mirror in the laser cavity. The grating tilting system has a considerable mechanical inertness, so static laser frequency calibration leads to false results. The proposed real-time dynamic calibration based on the identification of primary- and Gouy-effect type secondary interference peaks with known frequency and temporal history can be used for a wide scanning range (from 0.2 GHz to more than 1 GHz). A concave spherical mirror with a radius of R = 100 cm and a plain 1% transmitting mirror was used as a Fabry-Pérot interferometer with various resonator lengths to investigate and demonstrate real-time calibration procedures for two kinds of laser frequency scanning functions.

  17. Real-time dynamic calibration of a tunable frequency laser source using a Fabry-Pérot interferometer.

    PubMed

    Mandula, Gábor; Kis, Zsolt; Lengyel, Krisztián

    2015-12-01

    We report on a method for real-time dynamic calibration of a tunable external cavity diode laser by using a partially mode-matched plano-concave Fabry-Pérot interferometer in reflection geometry. Wide range laser frequency scanning is carried out by piezo-driven tilting of a diffractive grating playing the role of a frequency selective mirror in the laser cavity. The grating tilting system has a considerable mechanical inertness, so static laser frequency calibration leads to false results. The proposed real-time dynamic calibration based on the identification of primary- and Gouy-effect type secondary interference peaks with known frequency and temporal history can be used for a wide scanning range (from 0.2 GHz to more than 1 GHz). A concave spherical mirror with a radius of R = 100 cm and a plain 1% transmitting mirror was used as a Fabry-Pérot interferometer with various resonator lengths to investigate and demonstrate real-time calibration procedures for two kinds of laser frequency scanning functions. PMID:26724003

  18. Real-time dynamic calibration of a tunable frequency laser source using a Fabry-Pérot interferometer

    NASA Astrophysics Data System (ADS)

    Mandula, Gábor; Kis, Zsolt; Lengyel, Krisztián

    2015-12-01

    We report on a method for real-time dynamic calibration of a tunable external cavity diode laser by using a partially mode-matched plano-concave Fabry-Pérot interferometer in reflection geometry. Wide range laser frequency scanning is carried out by piezo-driven tilting of a diffractive grating playing the role of a frequency selective mirror in the laser cavity. The grating tilting system has a considerable mechanical inertness, so static laser frequency calibration leads to false results. The proposed real-time dynamic calibration based on the identification of primary- and Gouy-effect type secondary interference peaks with known frequency and temporal history can be used for a wide scanning range (from 0.2 GHz to more than 1 GHz). A concave spherical mirror with a radius of R = 100 cm and a plain 1% transmitting mirror was used as a Fabry-Pérot interferometer with various resonator lengths to investigate and demonstrate real-time calibration procedures for two kinds of laser frequency scanning functions.

  19. Real-time dynamic calibration of a tunable frequency laser source using a Fabry-Pérot interferometer.

    PubMed

    Mandula, Gábor; Kis, Zsolt; Lengyel, Krisztián

    2015-12-01

    We report on a method for real-time dynamic calibration of a tunable external cavity diode laser by using a partially mode-matched plano-concave Fabry-Pérot interferometer in reflection geometry. Wide range laser frequency scanning is carried out by piezo-driven tilting of a diffractive grating playing the role of a frequency selective mirror in the laser cavity. The grating tilting system has a considerable mechanical inertness, so static laser frequency calibration leads to false results. The proposed real-time dynamic calibration based on the identification of primary- and Gouy-effect type secondary interference peaks with known frequency and temporal history can be used for a wide scanning range (from 0.2 GHz to more than 1 GHz). A concave spherical mirror with a radius of R = 100 cm and a plain 1% transmitting mirror was used as a Fabry-Pérot interferometer with various resonator lengths to investigate and demonstrate real-time calibration procedures for two kinds of laser frequency scanning functions.

  20. Conceptual study of moderately coupled plasmas and experimental comparison of laboratory x-ray sources

    SciTech Connect

    Li, C.

    1993-12-01

    In this thesis the fundamental concepts of moderately coupled plasmas, for which 2{approx_lt}ln{Lambda}{sub b}{approx_lt}10, are, for the first time, presented. This investigation is motivated because neither the conventional Fokker-Planck approximation [for weakly coupled plasmas (ln{Lambda}{sub b}{approx_lt}10)] nor the theory of dielectric response with correlations for strongly coupled plasmas (ln{Lambda}{sub b}{approx_lt}1) has satisfactorily addressed this regime. Specifically, herein the standard Fokker-Planck operator for Coulomb collisions has been modified to include hitherto neglected terms that are directly associated with large-angle scattering. In addition a reduced electron-ion collision operator has been calculated that, for the first time, manifests 1/ln{Lambda}{sub b} corrections. Precise calculations of some relaxation rates and crude calculations of electron transport coefficients have been made. As one of major applications of the modified Fokker-Planck equation, the stopping powers and {rho}R have been calculated for charged fusion products ({alpha}`s, {sup 3}H, {sup 3}He) and hot electrons interacting with plasmas relevant to inertial confinement fusion. In the second major topic of this thesis, advances made in the area of laboratory x-ray sources are presented. First, and most importantly, through the use a Cockcroft-Walton linear accelerator, a charged particle induced x-ray emission (PIXE) source has been developed. Intense line x radiation (including K-, L-, M-, and N-lines) with wavelengths from 0.5 {angstrom} to 111 {angstrom} have been successfully produced. Second, a new high intensity electron-beam x-ray generator has also been developed, and it has been used with advantage in the soft x-ray region ( < 3 keV). Finally, a direct comparisons of both sources (PIXE and electron-beam x-ray sources) to a commercially available radioactive {alpha} fluorescent x-ray source has been made.

  1. Calibration method for a photoacoustic system for real time source apportionment of light absorbing carbonaceous aerosol based on size distribution measurements

    NASA Astrophysics Data System (ADS)

    Utry, Noemi; Ajtai, Tibor; Pinter, Mate; Orvos, Peter I.; Szabo, Gabor; Bozoki, Zoltan

    2016-04-01

    In this study, we introduce a calibration method with which sources of light absorbing carbonaceous particulate matter (LAC) can be apportioned in real time based on multi wavelength optical absorption measurements with a photoacoustic system. The method is primary applicable in wintry urban conditions when LAC is dominated by traffic and biomass burning. The proposed method was successfully tested in a field campaign in the city center of Szeged, Hungary during winter time where the dominance of traffic and wood burning aerosol has been experimentally demonstrated earlier. With the help of the proposed calibration method a relationship between the measured Aerosol Angström Exponent (AAE) and the number size distribution can be deduced. Once the calibration curve is determined, the relative strength of the two pollution sources can be deduced in real time as long as the light absorbing fraction of PM is exclusively related to traffic and wood burning. This assumption is indirectly confirmed in the presented measurement campaign by the fact that the measured size distribution is composed of two unimodal size distributions identified to correspond to traffic and wood burning aerosols. The proposed method offers the possibility of replacing laborious chemical analysis with simple in-situ measurement of aerosol size distribution data.

  2. Absolute Energy Calibration with the Neutron-Activated Liquid-Source System at BaBar's CsI(Tl) Calorimeter

    SciTech Connect

    Bauer, J

    2004-01-05

    The electro-magnetic calorimeter at the BABAR detector, part of the asymmetric B Factory at SLAC, measures photons in the energy range from 20 MeV to 8 GeV with good resolution. The calorimeter is calibrated at the low energy end with 6.13 MeV photons obtained from a liquid source system. During the calibration, a fluorine-rich liquid is activated via a neutron generator and pumped past the front of the calorimeter's crystals. Decays that occur in front of the crystals emit photons of well-defined energy, which are detected in the crystals with the regular data acquisition system. The liquid source system adds only very little material in front of the calorimeter, needs nearly no maintenance, and allows operation at the switch of a key with minimal safety hazards. The report describes the system, presents calibration results obtained from its operation since 1999, shows the crystals' loss of light yield due to radiation damage, and shares experiences gained over the years.

  3. Inter-laboratory calibration of natural gas round robins for δ2H and δ13C using off-line and on-line techniques

    USGS Publications Warehouse

    Dai, Jinxing; Xia, Xinyu; Li, Zhisheng; Coleman, Dennis D.; Dias, Robert F.; Gao, Ling; Li, Jian; Deev, Andrei; Li, Jin; Dessort, Daniel; Duclerc, Dominique; Li, Liwu; Liu, Jinzhong; Schloemer, Stefan; Zhang, Wenlong; Ni, Yunyan; Hu, Guoyi; Wang, Xiaobo; Tang, Yongchun

    2012-01-01

    Compound-specific carbon and hydrogen isotopic compositions of three natural gas round robins were calibrated by ten laboratories carrying out more than 800 measurements including both on-line and off-line methods. Two-point calibrations were performed with international measurement standards for hydrogen isotope ratios (VSMOW and SLAP) and carbon isotope ratios (NBS 19 and L-SVEC CO2). The consensus δ13C values and uncertainties were derived from the Maximum Likelihood Estimation (MLE) based on off-line measurements; the consensus δ2H values and uncertainties were derived from MLE of both off-line and on-line measurements, taking the bias of on-line measurements into account. The calibrated consensus values in ‰ relative to VSMOW and VPDB are: NG1 (coal-related gas): Methane: δ2HVSMOW = − 185.1‰ ± 1.2‰, δ13CVPDB = − 34.18‰ ± 0.10‰ Ethane: δ2HVSMOW = − 156.3‰ ± 1.8‰, δ13CVPDB = − 24.66‰ ± 0.11‰ Propane: δ2HVSMOW = − 143.6‰ ± 3.3‰, δ13CVPDB = − 22.21‰ ± 0.11‰ i-Butane: δ13CVPDB = − 21.62‰ ± 0.12‰ n-Butane: δ13CVPDB = − 21.74‰ ± 0.13‰ CO2: δ13CVPDB = − 5.00‰ ± 0.12‰ NG2 (biogas): Methane: δ2HVSMOW = − 237.0‰ ± 1.2‰, δ13CVPDB = − 68.89‰ ± 0.12‰ NG3 (oil-related gas): Methane: δ2HVSMOW = − 167.6‰ ± 1.0‰, δ13CVPDB = − 43.61‰ ± 0.09‰ Ethane: δ2HVSMOW = − 164.1‰ ± 2.4‰, δ13CVPDB = − 40.24‰ ± 0.10‰ Propane: δ2HVSMOW = − 138.4‰ ± 3.0‰, δ13CVPDB = − 33.79‰ ± 0.09‰ All of the assigned values are traceable to the international carbon isotope standard of VPDB and hydrogen isotope standard of VSMOW.

  4. HENC performance evaluation and plutonium calibration

    SciTech Connect

    Menlove, H.O.; Baca, J.; Pecos, J.M.; Davidson, D.R.; McElroy, R.D.; Brochu, D.B.

    1997-10-01

    The authors have designed a high-efficiency neutron counter (HENC) to increase the plutonium content in 200-L waste drums. The counter uses totals neutron counting, coincidence counting, and multiplicity counting to determine the plutonium mass. The HENC was developed as part of a Cooperative Research and Development Agreement between the Department of Energy and Canberra Industries. This report presents the results of the detector modifications, the performance tests, the add-a-source calibration, and the plutonium calibration at Los Alamos National Laboratory (TA-35) in 1996.

  5. Comparison of spectral radiance responsivity calibration techniques used for backscatter ultraviolet satellite instruments

    NASA Astrophysics Data System (ADS)

    Kowalewski, M. G.; Janz, S. J.

    2015-02-01

    Methods of absolute radiometric calibration of backscatter ultraviolet (BUV) satellite instruments are compared as part of an effort to minimize pre-launch calibration uncertainties. An internally illuminated integrating sphere source has been used for the Shuttle Solar BUV, Total Ozone Mapping Spectrometer, Ozone Mapping Instrument, and Global Ozone Monitoring Experiment 2 using standardized procedures traceable to national standards. These sphere-based spectral responsivities agree to within the derived combined standard uncertainty of 1.87% relative to calibrations performed using an external diffuser illuminated by standard irradiance sources, the customary spectral radiance responsivity calibration method for BUV instruments. The combined standard uncertainty for these calibration techniques as implemented at the NASA Goddard Space Flight Center’s Radiometric Calibration and Development Laboratory is shown to less than 2% at 250 nm when using a single traceable calibration standard.

  6. A New Electron Source for Laboratory Simulation of the Space Environment

    NASA Technical Reports Server (NTRS)

    Krause, Linda Habash; Everding, Daniel; Bonner, Mathew; Swan, Brian

    2012-01-01

    We have developed a new collimated electron source called the Photoelectron Beam Generator (PEBG) for laboratory and spaceflight applications. This technology is needed to replace traditional cathodes because of serious fundamental weaknesses with the present state of the art. Filament cathodes suffer from numerous practical problems, even if expertly designed, including the dependence of electron emission on filament temperature, short lifetimes (approx 100 hours), and relatively high power (approx 10s of W). Other types of cathodes have solved some of these problems, but they are plagued with other difficult problems, such as the Spindt cathode's extreme sensitivity to molecular oxygen. None to date have been able to meet the demand of long lifetime, robust packaging, and precision energy and flux control. This new cathode design avoids many common pitfalls of traditional cathodes. Specifically, there are no fragile parts, no sensitivity to oxygen, no intrinsic emission dependencies on device temperature, and no vacuum requirements for protecting the source from contamination or damage. Recent advances in high-brightness Light Emitting Diodes (LEDs) have provided the key enabling technology for this new electron source. The LEDs are used to photoeject electrons off a target material of a low work-function, and these photoelectrons are subsequently focused into a laminar beam using electrostatic lenses. The PEBG works by illuminating a target material and steering photoelectrons into a laminar beam using electrostatic lenses

  7. Phase Contrast Imaging with Coded Apertures Using Laboratory-Based X-ray Sources

    SciTech Connect

    Ignatyev, K.; Munro, P. R. T.; Speller, R. D.; Olivo, A.

    2011-09-09

    X-ray phase contrast imaging is a powerful technique that allows detection of changes in the phase of x-ray wavefronts as they pass through a sample. As a result, details not visible in conventional x-ray absorption imaging can be detected. Until recently the majority of applications of phase contrast imaging were at synchrotron facilities due to the availability of their high flux and coherence; however, a number of techniques have appeared recently that allow phase contrast imaging to be performed using laboratory sources. Here we describe a phase contrast imaging technique, developed at University College London, that uses two coded apertures. The x-ray beam is shaped by the pre-sample aperture, and small deviations in the x-ray propagation direction are detected with the help of the detector aperture. In contrast with other methods, it has a much more relaxed requirement for the source size (it works with source sizes up to 100 {mu}m). A working prototype coded-aperture system has been built. An x-ray detector with directly deposited columnar CsI has been used to minimize signal spill-over into neighboring pixels. Phase contrast images obtained with the system have demonstrated its effectiveness for imaging low-absorption materials.

  8. Source document for waste area groupings at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    SciTech Connect

    Osborne, P.L.; Kuhaida, A.J., Jr.

    1996-09-01

    This document serves as a source document for Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and other types of documents developed for and pertaining to Environmental Restoration (ER) Program activities at Oak Ridge National Laboratory (ORNL). It contains descriptions of the (1) regulatory requirements for the ORR ER Program, (2) Oak Ridge Reservation (ORR) ER Program, (3) ORNL site history and characterization, and (4) history and characterization of Waste Area Groupings (WAGS) 1-20. This document was created to save time, effort, and money for persons and organizations drafting documents for the ER Program and to improve consistency in the documents prepared for the program. By eliminating the repetitious use of selected information about the program, this document will help reduce the time and costs associated with producing program documents. By serving as a benchmark for selected information about the ER Program, this reference will help ensure that information presented in future documents is accurate and complete.

  9. Certification testing of the Los Alamos National Laboratory Heat Source/Radioisotopic Thermoelectric Generator shipping container

    SciTech Connect

    Bronowski, D.R.; Madsen, M.M.

    1991-09-01

    The Heat Source/Radioisotopic Thermoelectric Generator shipping counter is a Type B packaging currently under development by Los Alamos National Laboratory. Type B packaging for transporting radioactive material is required to maintain containment and shielding after being exposed to normal and hypothetical accident environments defined in Title 10 of the Code of Federal Regulations Part 71. A combination of testing and analysis is used to verify the adequacy of this packaging design. This report documents the testing portion of the design verification. Six tests were conducted on a prototype package: a water spray test, a 4-foot normal conditions drop test, a 30-foot drop test, a 40-inch puncture test, a 30-minute thermal test, and an 8-hour immersion test.

  10. Structural testing of the Los Alamos National Laboratory Heat Source/Radioisotopic Thermoelectric Generator shipping container

    SciTech Connect

    Bronowski, D.R.; Madsen, M.M.

    1991-06-01

    The Heat Source/Radioisotopic Thermoelectric Generator shipping container is a Type B packaging design currently under development by Los Alamos National Laboratory. Type B packaging for transporting radioactive material is required to maintain containment and shielding after being exposed to the normal and hypothetical accident environments defined in Title 10 Code of Federal Regulations Part 71. A combination of testing and analysis is used to verify the adequacy of this package design. This report documents the test program portion of the design verification, using several prototype packages. Four types of testing were performed: 30-foot hypothetical accident condition drop tests in three orientations, 40-inch hypothetical accident condition puncture tests in five orientations, a 21 psi external overpressure test, and a normal conditions of transport test consisting of a water spray and a 4 foot drop test. 18 refs., 104 figs., 13 tabs.

  11. Propagation-based phase-contrast tomography for high-resolution lung imaging with laboratory sources

    NASA Astrophysics Data System (ADS)

    Krenkel, Martin; Töpperwien, Mareike; Dullin, Christian; Alves, Frauke; Salditt, Tim

    2016-03-01

    We have performed high-resolution phase-contrast tomography on whole mice with a laboratory setup. Enabled by a high-brilliance liquid-metal-jet source, we show the feasibility of propagation-based phase contrast in local tomography even in the presence of strongly absorbing surrounding tissue as it is the case in small animal imaging of the lung. We demonstrate the technique by reconstructions of the mouse lung for two different fields of view, covering the whole organ, and a zoom to the local finer structure of terminal airways and alveoli. With a resolution of a few micrometers and the wide availability of the technique, studies of larger biological samples at the cellular level become possible.

  12. Developing small vacuum spark as an x-ray source for calibration of an x-ray focusing crystal spectrometer

    SciTech Connect

    Ghomeishi, Mostafa; Adikan, Faisal Rafiq Mahamd; Karami, Mohammad

    2012-10-15

    A new technique of x-ray focusing crystal spectrometers' calibration is the desired result. For this purpose the spectrometer is designed to register radiated copper K{alpha} and K{beta} lines by using a flat {alpha}-quartz crystal. This experiment uses pre-breakdown x-ray emissions in low vacuum of about 2.5-3 mbar. At this pressure the pinch will not form so the plasma will not radiate. The anode material is copper and the capacity of the capacitor bank is 22.6 nF. This experiment designed and mounted a repetitive triggering system to save the operator time making hundreds of shots. This emission amount is good for calibration and geometrical adjustment of an optical crystal x-ray focusing spectrometer.

  13. Developing small vacuum spark as an x-ray source for calibration of an x-ray focusing crystal spectrometer.

    PubMed

    Ghomeishi, Mostafa; Karami, Mohammad; Adikan, Faisal Rafiq Mahamd

    2012-10-01

    A new technique of x-ray focusing crystal spectrometers' calibration is the desired result. For this purpose the spectrometer is designed to register radiated copper Kα and Kβ lines by using a flat α-quartz crystal. This experiment uses pre-breakdown x-ray emissions in low vacuum of about 2.5-3 mbar. At this pressure the pinch will not form so the plasma will not radiate. The anode material is copper and the capacity of the capacitor bank is 22.6 nF. This experiment designed and mounted a repetitive triggering system to save the operator time making hundreds of shots. This emission amount is good for calibration and geometrical adjustment of an optical crystal x-ray focusing spectrometer. PMID:23126754

  14. Absolute Radiometric Calibration of EUNIS-06

    NASA Technical Reports Server (NTRS)

    Thomas, R. J.; Rabin, D. M.; Kent, B. J.; Paustian, W.

    2007-01-01

    The Extreme-Ultraviolet Normal-Incidence Spectrometer (EUNIS) is a soundingrocket payload that obtains imaged high-resolution spectra of individual solar features, providing information about the Sun's corona and upper transition region. Shortly after its successful initial flight last year, a complete end-to-end calibration was carried out to determine the instrument's absolute radiometric response over its Longwave bandpass of 300 - 370A. The measurements were done at the Rutherford-Appleton Laboratory (RAL) in England, using the same vacuum facility and EUV radiation source used in the pre-flight calibrations of both SOHO/CDS and Hinode/EIS, as well as in three post-flight calibrations of our SERTS sounding rocket payload, the precursor to EUNIS. The unique radiation source provided by the Physikalisch-Technische Bundesanstalt (PTB) had been calibrated to an absolute accuracy of 7% (l-sigma) at 12 wavelengths covering our bandpass directly against the Berlin electron storage ring BESSY, which is itself a primary radiometric source standard. Scans of the EUNIS aperture were made to determine the instrument's absolute spectral sensitivity to +- 25%, considering all sources of error, and demonstrate that EUNIS-06 was the most sensitive solar E W spectrometer yet flown. The results will be matched against prior calibrations which relied on combining measurements of individual optical components, and on comparisons with theoretically predicted 'insensitive' line ratios. Coordinated observations were made during the EUNIS-06 flight by SOHO/CDS and EIT that will allow re-calibrations of those instruments as well. In addition, future EUNIS flights will provide similar calibration updates for TRACE, Hinode/EIS, and STEREO/SECCHI/EUVI.

  15. Monitoring of event-based mobilization of hydrophobic pollutants in rivers: calibration of turbidity as a proxy for particle facilitated transport in field and laboratory.

    PubMed

    Rügner, Hermann; Schwientek, Marc; Egner, Marius; Grathwohl, Peter

    2014-08-15

    Transport of many pollutants in rivers is coupled to mobilization of suspended particles which typically occurs during floods. Since the amount of total suspended solids (TSS) in rivers can be monitored by turbidity measurements this may be used as a proxy for the total concentration of particle associated pollutants such as PAHs, PCBs, etc. and several heavy metals. Online turbidity measurements (e.g. by optical backscattering sensors) would then also allow for an assessment of particle and pollutant flux dynamics if once calibrated against TSS and total pollutant concentrations for a given catchment. In this study, distinct flood and thus turbidity events were sampled at high temporal resolution in three contrasting sub-catchments of the River Neckar in Southwest Germany (Ammer, Goldersbach, Steinlach) as well as in the River Neckar itself and investigated for the total amount of PAHs and TSS in water; turbidity (NTU) and grain size distributions of suspended solids were determined as well. Laboratory experiments were performed with natural river bed sediments from different locations (Ammer) to investigate PAH concentrations, TSS and turbidity during sedimentation of suspended particles under controlled conditions (yielding smaller and smaller suspended particles and TSS with time). Laboratory and field results agreed very well and showed that turbidity and TSS were linearly correlated over an extended turbidity range up to 2000 NTU for the field samples and up to 8000 NTU in lab experiments. This also holds for total PAH concentrations which can be reasonably well predicted based on turbidity measurements and TSS vs. PAHs relationships - even for high turbidity values observed during flood events (>2000 NTU). Total PAH concentrations on suspended solids were independent of grain size of suspended particles. This implies that for the rivers investigated the sorption capacity of particles did not change significantly during the observed events.

  16. Comprehensive inter-laboratory calibration of reference materials for delta18O versus VSMOW using various on-line high-temperature conversion techniques.

    PubMed

    Brand, Willi A; Coplen, Tyler B; Aerts-Bijma, Anita T; Böhlke, J K; Gehre, Matthias; Geilmann, Heike; Gröning, Manfred; Jansen, Henk G; Meijer, Harro A J; Mroczkowski, Stanley J; Qi, Haiping; Soergel, Karin; Stuart-Williams, Hilary; Weise, Stephan M; Werner, Roland A

    2009-04-01

    Internationally distributed organic and inorganic oxygen isotopic reference materials have been calibrated by six laboratories carrying out more than 5300 measurements using a variety of high-temperature conversion techniques (HTC)a in an evaluation sponsored by the International Union of Pure and Applied Chemistry (IUPAC). To aid in the calibration of these reference materials, which span more than 125 per thousand, an artificially enriched reference water (delta(18)O of +78.91 per thousand) and two barium sulfates (one depleted and one enriched in (18)O) were prepared and calibrated relative to VSMOW2b and SLAP reference waters. These materials were used to calibrate the other isotopic reference materials in this study, which yielded: Reference material delta(18)O and estimated combined uncertainty IAEA-602 benzoic acid+71.28 +/- 0.36 per thousand USGS 35 sodium nitrate+56.81 +/- 0.31 per thousand IAEA-NO-3 potassium nitrate+25.32 +/- 0.29 per thousand IAEA-601 benzoic acid+23.14 +/- 0.19 per thousand IAEA-SO-5 barium sulfate+12.13 +/- 0.33 per thousand NBS 127 barium sulfate+8.59 +/- 0.26 per thousand VSMOW2 water 0 per thousand IAEA-600 caffeine-3.48 +/- 0.53 per thousand IAEA-SO-6 barium sulfate-11.35 +/- 0.31 per thousand USGS 34 potassium nitrate-27.78 +/- 0.37 per thousand SLAP water-55.5 per thousand The seemingly large estimated combined uncertainties arise from differences in instrumentation and methodology and difficulty in accounting for all measurement bias. They are composed of the 3-fold standard errors directly calculated from the measurements and provision for systematic errors discussed in this paper. A primary conclusion of this study is that nitrate samples analyzed for delta(18)O should be analyzed with internationally distributed isotopic nitrates, and likewise for sulfates and organics. Authors reporting relative differences of oxygen-isotope ratios (delta(18)O) of nitrates, sulfates, or organic material should explicitly state in their

  17. Comprehensive inter-laboratory calibration of reference materials for delta18O versus VSMOW using various on-line high-temperature conversion techniques.

    PubMed

    Brand, Willi A; Coplen, Tyler B; Aerts-Bijma, Anita T; Böhlke, J K; Gehre, Matthias; Geilmann, Heike; Gröning, Manfred; Jansen, Henk G; Meijer, Harro A J; Mroczkowski, Stanley J; Qi, Haiping; Soergel, Karin; Stuart-Williams, Hilary; Weise, Stephan M; Werner, Roland A

    2009-04-01

    Internationally distributed organic and inorganic oxygen isotopic reference materials have been calibrated by six laboratories carrying out more than 5300 measurements using a variety of high-temperature conversion techniques (HTC)a in an evaluation sponsored by the International Union of Pure and Applied Chemistry (IUPAC). To aid in the calibration of these reference materials, which span more than 125 per thousand, an artificially enriched reference water (delta(18)O of +78.91 per thousand) and two barium sulfates (one depleted and one enriched in (18)O) were prepared and calibrated relative to VSMOW2b and SLAP reference waters. These materials were used to calibrate the other isotopic reference materials in this study, which yielded: Reference material delta(18)O and estimated combined uncertainty IAEA-602 benzoic acid+71.28 +/- 0.36 per thousand USGS 35 sodium nitrate+56.81 +/- 0.31 per thousand IAEA-NO-3 potassium nitrate+25.32 +/- 0.29 per thousand IAEA-601 benzoic acid+23.14 +/- 0.19 per thousand IAEA-SO-5 barium sulfate+12.13 +/- 0.33 per thousand NBS 127 barium sulfate+8.59 +/- 0.26 per thousand VSMOW2 water 0 per thousand IAEA-600 caffeine-3.48 +/- 0.53 per thousand IAEA-SO-6 barium sulfate-11.35 +/- 0.31 per thousand USGS 34 potassium nitrate-27.78 +/- 0.37 per thousand SLAP water-55.5 per thousand The seemingly large estimated combined uncertainties arise from differences in instrumentation and methodology and difficulty in accounting for all measurement bias. They are composed of the 3-fold standard errors directly calculated from the measurements and provision for systematic errors discussed in this paper. A primary conclusion of this study is that nitrate samples analyzed for delta(18)O should be analyzed with internationally distributed isotopic nitrates, and likewise for sulfates and organics. Authors reporting relative differences of oxygen-isotope ratios (delta(18)O) of nitrates, sulfates, or organic material should explicitly state in their

  18. Halogen oxides: Radicals, sources and reservoirs in the laboratory and in the atmosphere

    NASA Astrophysics Data System (ADS)

    Wayne, R. P.; Poulet, G.; Biggs, P.; Burrows, J. P.; Cox, R. A.; Crutzen, P. J.; Hayman, G. D.; Jenkin, M. E.; Le Bras, G.; Moortgat, G. K.; Platt, U.; Schindler, R. N.

    The central topic of this review concerns the species XO, where X is F, Cl, Br or I. These molecules are thus the radicals FO, ClO, BrO and IO, but attention is also given to some of their precursors in the laboratory and the atmosphere, as well as to their reservoirs, sinks, and other related species of potential atmospheric importance. Laboratory data on the physics and chemistry of the species and atmospheric determinations of their concentrations are both considered. One aim of the review is to highlight the relationship between the laboratory investigations and the atmospheric studies. The emphasis of the review is on gas-phase processes. After a brief introductory section, the review continues with an examination of laboratory techniques for the study of the halogen-oxide species. This section fast looks at the general properties of the oxides and sources of them for laboratory experiments, then discusses the detection and measurement of the monoxide radicals in the laboratory, and ends with a description of the kinetic tools that have been harnessed in the various studies. The spectroscopy, structure, photochemistry and thermochemistry, of the halogen oxides are discussed in Section III. Both experimental and theoretical aspects are presented. The objectives of the work described are on the one hand to establish the basis for the detection of the radical and the measurement of its concentration in the laboratory and in the atmosphere, and on the other to provide the framework for interpreting pathways, mechanisms and efficiencies of photochemical and thermal reactions. Sections IV, V and VI of the review address the main issues of observed chemistry and its kinetics. Section IV gathers together available kinetic and mechanistic information on gas-phase reactions of FO, ClO, BrO and IO radicals, and the available data are summarized in appropriate tables. Section V reports on the corresponding data available for the gas-phase reactions of certain species

  19. A flexible setup for angle-resolved X-ray fluorescence spectrometry with laboratory sources.

    PubMed

    Spanier, M; Herzog, C; Grötzsch, D; Kramer, F; Mantouvalou, I; Lubeck, J; Weser, J; Streeck, C; Malzer, W; Beckhoff, B; Kanngießer, B

    2016-03-01

    X-ray fluorescence (XRF) analysis is one of the standard tools for the analysis of stratified materials and is widely applied for the investigation of electronics and coatings. The composition and thickness of the layers can be determined quantitatively and non-destructively. Recent work showed that these capabilities can be extended towards retrieving stratigraphic information like concentration depth profiles using angle-resolved XRF (ARXRF). This paper introduces an experimental sample chamber which was developed as a multi-purpose tool enabling different measurement geometries suited for transmission measurements, conventional XRF, ARXRF, etc. The chamber was specifically designed for attaching all kinds of laboratory X-ray sources for the soft and hard X-ray ranges as well as various detection systems. In detail, a setup for ARXRF using an X-ray tube with a polycapillary X-ray lens as source is presented. For such a type of setup, both the spectral and lateral characterizations of the radiation field are crucial for quantitative ARXRF measurements. The characterization is validated with the help of a stratified validation sample. PMID:27036820

  20. A flexible setup for angle-resolved X-ray fluorescence spectrometry with laboratory sources

    NASA Astrophysics Data System (ADS)

    Spanier, M.; Herzog, C.; Grötzsch, D.; Kramer, F.; Mantouvalou, I.; Lubeck, J.; Weser, J.; Streeck, C.; Malzer, W.; Beckhoff, B.; Kanngießer, B.

    2016-03-01

    X-ray fluorescence (XRF) analysis is one of the standard tools for the analysis of stratified materials and is widely applied for the investigation of electronics and coatings. The composition and thickness of the layers can be determined quantitatively and non-destructively. Recent work showed that these capabilities can be extended towards retrieving stratigraphic information like concentration depth profiles using angle-resolved XRF (ARXRF). This paper introduces an experimental sample chamber which was developed as a multi-purpose tool enabling different measurement geometries suited for transmission measurements, conventional XRF, ARXRF, etc. The chamber was specifically designed for attaching all kinds of laboratory X-ray sources for the soft and hard X-ray ranges as well as various detection systems. In detail, a setup for ARXRF using an X-ray tube with a polycapillary X-ray lens as source is presented. For such a type of setup, both the spectral and lateral characterizations of the radiation field are crucial for quantitative ARXRF measurements. The characterization is validated with the help of a stratified validation sample.

  1. Pulsed neutrons: One year of experience with the new source at Argonne National Laboratory

    NASA Astrophysics Data System (ADS)

    Lander, G. H.

    1983-05-01

    The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a spallation neutron source based on a 500 MeV proton accelerator operating at 30 Hz and with an average proton current of ≈ 10 μA. Neutron scattering instruments for elastic scattering include two powder diffractometers, a single-crystal diffractometer based on the Laue method and employing a large (30 x 30 cm) position-sensitive scintillation detector, a small-angle diffractometer using a position-sensitive detector, and a polarized-neutron diffractometer which will utilize the spin-refrigerator device to obtain a beam of white polarized neutrons. For inelastic scattering we presently have the crystal-analyzer spectrometer, and two chopper spectrometers capable of providing monoenergetic incident neutron beams of between 100 and 600 meV. From its inception IPNS has been operating in a user mode and the selection of experiments is made by a Program Committee twice a year on the basis of the scientifi cmerit of submitted proposals.

  2. Design of an inexpensive integrating sphere student laboratory setup for the optical characterization of light sources

    NASA Astrophysics Data System (ADS)

    Leloup, Frédéric B.; Leyre, Sven; Bauwens, Eva; Van den Abeele, Toon; Hanselaer, Peter

    2016-01-01

    In this paper, the design of an inexpensive integrating sphere setup is presented, enabling students to perform optical characterization of light sources with reasonable accuracy, in a student laboratory context. Instead of using an expensive sphere with magnesium oxide or barium sulfate coating, a cheap polystyrene sphere is employed. In combination with a low-cost USB spectroradiometer, the system enables the direct measurement of the spectral radiant power of a light source. In addition to the radiant power, the luminous flux, luminous efficacy, and distinctive colorimetric quantities (colour coordinates, colour temperature, and colour rendering index) can be determined. Besides a description of the equipment used, the experimental measurement procedure and some typical measurement results are presented. A comparison between the data and the results obtained with scientific metrology instrumentation indicates reasonable accuracy. As a result, it can be concluded that the purpose of the presented experiments, being that students become acquainted with applications of radiometry and photometry, and with data collection and data analysis as in a professional context, is fully achieved with the described test setup.

  3. Mathematical calibration of Ge detectors, and the instruments that use them

    SciTech Connect

    Bronson, F.L.; Young, B.

    1997-11-01

    Efficiency calibrations for Ge detectors are typically done with the use of multiple energy calibrations sources which are added to a bulk matrix intended to simulate the measurement sample, and then deposited in the sample container. This is rather easy for common laboratory samples. Bu, even there, for many environmental samples, waste assay samples, and operational health physics samples, accurate calibrations are difficult. For these situations, various mathematical corrections or direct calibration techniques are used at Canberra. EML has pioneered the use of mathematical calibrations following source-based detector characterization measurements for in situ measurements of environmental fallout. Canberra has expanded this by the use of MCNP for the source measurements required in EML. For other calibration situations, MCNP was used directly, as the primary calibration method. This is demonstrated to be at least as accurate as source based measurements, and probably better. Recently, a new method [ISOCS] has been developed and is nearing completion. This promises to be an easy to use calibration software that can be used by the customer for in situ gamma spectroscopy to accurately measure many large sized samples, such as boxes, drums, pipes, or to calibrate small laboratory-type samples. 8 refs., 8 figs., 5 tabs.

  4. Development and calibration of mirrors and gratings for the Soft X-ray materials science beamline at the Linac Coherent Light Source free-electron laser

    DOE PAGES

    Soufli, Regina; Fernandez-Perea, Monica; Baker, Sherry L.; Robinson, Jeff C.; Gullikson, Eric M.; Heimann, Philip; Yashchuk, Valerie V.; McKinney, Wayne R.; Schlotter, William F.; Rowen, Michael

    2012-04-18

    This article discusses the development and calibration of the x-ray reflective and diffractive elements for the Soft X-ray Materials Science (SXR) beamline of the Linac Coherent Light Source (LCLS) free-electron laser (FEL), designed for operation in the 500 – 2000 eV region. The surface topography of three Si mirror substrates and two Si diffraction grating substrates was examined by atomic force microscopy (AFM) and optical profilometry. The figure of the mirror substrates was also verified via surface slope measurements with a long trace profiler. A boron carbide (B4C) coating especially optimized for the LCLS FEL conditions was deposited on allmore » SXR mirrors and gratings. Coating thickness uniformity of 0.14 nm root mean square (rms) across clear apertures extending to 205 mm length was demonstrated for all elements, as required to preserve the coherent wavefront of the LCLS source. The reflective performance of the mirrors and the diffraction efficiency of the gratings were calibrated at beamline 6.3.2 at the Advanced Light Source synchrotron. To verify the integrity of the nanometer-scale grating structure, the grating topography was examined by AFM before and after coating. This is to our knowledge the first time B4C-coated diffraction gratings are demonstrated for operation in the soft x-ray region.« less

  5. Development and calibration of mirrors and gratings for the soft x-ray materials science beamline at the Linac Coherent Light Source free-electron laser.

    PubMed

    Soufli, Regina; Fernández-Perea, Mónica; Baker, Sherry L; Robinson, Jeff C; Gullikson, Eric M; Heimann, Philip; Yashchuk, Valeriy V; McKinney, Wayne R; Schlotter, William F; Rowen, Michael

    2012-04-20

    This work discusses the development and calibration of the x-ray reflective and diffractive elements for the Soft X-ray Materials Science (SXR) beamline of the Linac Coherent Light Source (LCLS) free-electron laser (FEL), designed for operation in the 500 to 2000 eV region. The surface topography of three Si mirror substrates and two Si diffraction grating substrates was examined by atomic force microscopy (AFM) and optical profilometry. The figure of the mirror substrates was also verified via surface slope measurements with a long trace profiler. A boron carbide (B4C) coating especially optimized for the LCLS FEL conditions was deposited on all SXR mirrors and gratings. Coating thickness uniformity of 0.14 nm root mean square (rms) across clear apertures extending to 205 mm length was demonstrated for all elements, as required to preserve the coherent wavefront of the LCLS source. The reflective performance of the mirrors and the diffraction efficiency of the gratings were calibrated at beamline 6.3.2 at the Advanced Light Source synchrotron. To verify the integrity of the nanometer-scale grating structure, the grating topography was examined by AFM before and after coating. This is to our knowledge the first time B4C-coated diffraction gratings are demonstrated for operation in the soft x-ray region.

  6. Development and calibration of mirrors and gratings for the Soft X-ray materials science beamline at the Linac Coherent Light Source free-electron laser

    SciTech Connect

    Soufli, Regina; Fernandez-Perea, Monica; Baker, Sherry L.; Robinson, Jeff C.; Gullikson, Eric M.; Heimann, Philip; Yashchuk, Valerie V.; McKinney, Wayne R.; Schlotter, William F.; Rowen, Michael

    2012-04-18

    This article discusses the development and calibration of the x-ray reflective and diffractive elements for the Soft X-ray Materials Science (SXR) beamline of the Linac Coherent Light Source (LCLS) free-electron laser (FEL), designed for operation in the 500 – 2000 eV region. The surface topography of three Si mirror substrates and two Si diffraction grating substrates was examined by atomic force microscopy (AFM) and optical profilometry. The figure of the mirror substrates was also verified via surface slope measurements with a long trace profiler. A boron carbide (B4C) coating especially optimized for the LCLS FEL conditions was deposited on all SXR mirrors and gratings. Coating thickness uniformity of 0.14 nm root mean square (rms) across clear apertures extending to 205 mm length was demonstrated for all elements, as required to preserve the coherent wavefront of the LCLS source. The reflective performance of the mirrors and the diffraction efficiency of the gratings were calibrated at beamline 6.3.2 at the Advanced Light Source synchrotron. To verify the integrity of the nanometer-scale grating structure, the grating topography was examined by AFM before and after coating. This is to our knowledge the first time B4C-coated diffraction gratings are demonstrated for operation in the soft x-ray region.

  7. Phase 1 environmental report for the Advanced Neutron Source at Oak Ridge National Laboratory

    SciTech Connect

    Blasing, T.J.; Brown, R.A.; Cada, G.F.; Easterly, C.; Feldman, D.L.; Hagan, C.W.; Harrington, R.M.; Johnson, R.O.; Ketelle, R.H.; Kroodsma, R.L.; McCold, L.N.; Reich, W.J.; Scofield, P.A.; Socolof, M.L.; Taleyarkhan, R.P.; Van Dyke, J.W.

    1992-02-01

    The US Department of Energy (DOE) has proposed the construction and operation of the Advanced Neutron Source (ANS), a 330-MW(f) reactor, at Oak Ridge National Laboratory (ORNL) to support neutron scattering and nuclear physics experiments. ANS would provide a steady-state source of neutrons that are thermalized to produce sources of hot, cold, and very coal neutrons. The use of these neutrons in ANS experiment facilities would be an essential component of national research efforts in basic materials science. Additionally, ANS capabilities would include production of transplutonium isotopes, irradiation of potential fusion and fission reactor materials, activation analysis, and production of medical and industrial isotopes such as {sup 252}Cf. Although ANS would not require licensing by the US Nuclear Regulatory Commission (NRC), DOE regards the design, construction, and operation of ANS as activities that would produce a licensable facility; that is, DOE is following the regulatory guidelines that NRC would apply if NRC were licensing the facility. Those guidelines include instructions for the preparation of an environmental report (ER), a compilation of available data and preliminary analyses regarding the environmental impacts of nuclear facility construction and operation. The ER, described and outlined in NRC Regulatory Guide 4.2, serves as a background document to facilitate the preparation of environmental impact statements (EISs). Using Regulatory Guide 4.2 as a model, this ANS ER provides analyses and information specific to the ANS site and area that can be adopted (and modified, if necessary) for the ANS EIS. The ER is being prepared in two phases. Phase 1 ER includes many of the data and analyses needed to prepare the EIS but does not include data or analyses of alternate sites or alternate technologies. Phase 2 ER will include the additional data and analyses stipulated by Regulatory Guide 4.2.

  8. Emissions from laboratory combustion of wildland fuels: emission factors and source profiles.

    PubMed

    Chen, L W Antony; Moosmüller, Hans; Arnott, W Patrick; Chow, Judith C; Watson, John G; Susott, Ronald A; Babbitt, Ronald E; Wold, Cyle E; Lincoln, Emily N; Hao, Wei Min

    2007-06-15

    Combustion of wildland fuels represents a major source of particulate matter (PM) and light-absorbing elemental carbon (EC) on a national and global scale, but the emission factors and source profiles have not been well characterized with respect to different fuels and combustion phases. These uncertainties limit the accuracy of current emission inventories, smoke forecasts, and source apportionments. This study investigates the evolution of gaseous and particulate emission and combustion efficiency by burning wildland fuels in a laboratory combustion facility. Emission factors for carbon dioxide (CO2), carbon monoxide (CO), total hydrocarbon (THC), nitrogen oxides (NO(x)), PM, light extinction and absorption cross sections, and spectral scattering cross sections specific to flaming and smoldering phases are reported. Emission factors are generally reproducible within +/- 20% during the flaming phase, which, despite its short duration, dominates the carbon emission (mostly in the form of CO2) and the production of light absorption and EC. Higher and more variable emission factors for CO, THC, and PM are found during the smoldering phase, especially for fuels containing substantial moisture. Organic carbon (OC) and EC mass account for a majority (i.e., > 60%) of PM mass; other important elements include potassium, chlorine, and sulfur. Thermal analysis separates the EC into subfractions based on analysis temperature demonstrating that high-temperature EC (EC2; at 700 degrees C) varies from 1% to 70% of PM among biomass burns, compared to 75% in kerosene soot. Despite this, the conversion factor between EC and light absorption emissions is rather consistent across fuels and burns, ranging from 7.8 to 9.6 m2/g EC. Findings from this study should be considered in the development of PM and EC emission inventories for visibility and radiative forcing assessments.

  9. From laboratory results to models: Polyoxymethylene as a parent of formaldehyde extended source in comet Halley

    NASA Astrophysics Data System (ADS)

    Cottin, H.; Benilan, Y.; Fray, N.; Gazeau, M.; Raulin, F.

    Measurements performed by the NMS mass spectrometer on board Giotto show that the formaldehyde density profile, as a function of the distance to the nucleus of comet Halley, cannot be explained only by a direct release of formaldehyde from the nucleus. Understanding this observation requires an additional source of formaldehyde, which is most commonly called "extended source". Such a phenomenon is also detected in comets Hyakutake and Hale-Bopp. Presence of Polyoxymethylene (POM-polymer of formaldehyde) has often been debated to interpret H2 CO extended source but until very recently important quantitative data were missing to allow an appropriate analysis of this hypothesis. Formaldehyde production rate from POM on solid grains is a function of several unknown parameters: the matrix in which POM is imbedded, the geometry of the grains, the chemical structure of the polymer, its photodegradation rate and its temperature. We have obtained experimental data concerning the photo and thermal degradation of POM and modelled the contribution of potential solid POM on dust particles to the gaseous phase. First results were presented in (Cottin et al., 2001) for a single size population of grains, and temperature as a free parameter. We have now extended our model to a more realistic grain population, based on actual measurements in Halley coma, for which velocity and temperature of each grain are a function of its size and composition. We have calculated the best fits to Giotto measurements and derived the amount of POM required to account H2 CO observation. The results show that the presence of a few percent in mass of solid POM on grains can provide a realistic explanation to the formaldehyde extended source observed in several comets. Even if the model still needs to be improved, for example to include different grains geometry, it can already be used to test other molecules like Hexamethylenetetramine (HMT) or poly-HCN against known extended sources such as CN, C2 or

  10. Development of the front end test stand and vessel for extraction and source plasma analyses negative hydrogen ion sources at the Rutherford Appleton Laboratory

    SciTech Connect

    Lawrie, S. R.; Faircloth, D. C.; Letchford, A. P.; Perkins, M.; Whitehead, M. O.; Wood, T.; Gabor, C.; Back, J.

    2014-02-15

    The ISIS pulsed spallation neutron and muon facility at the Rutherford Appleton Laboratory (RAL) in the UK uses a Penning surface plasma negative hydrogen ion source. Upgrade options for the ISIS accelerator system demand a higher current, lower emittance beam with longer pulse lengths from the injector. The Front End Test Stand is being constructed at RAL to meet the upgrade requirements using a modified ISIS ion source. A new 10% duty cycle 25 kV pulsed extraction power supply has been commissioned and the first meter of 3 MeV radio frequency quadrupole has been delivered. Simultaneously, a Vessel for Extraction and Source Plasma Analyses is under construction in a new laboratory at RAL. The detailed measurements of the plasma and extracted beam characteristics will allow a radical overhaul of the transport optics, potentially yielding a simpler source configuration with greater output and lifetime.

  11. Design and calibration of field deployable ground-viewing radiometers.

    PubMed

    Anderson, Nikolaus; Czapla-Myers, Jeffrey; Leisso, Nathan; Biggar, Stuart; Burkhart, Charles; Kingston, Rob; Thome, Kurtis

    2013-01-10

    Three improved ground-viewing radiometers were built to support the Radiometric Calibration Test Site (RadCaTS) developed by the Remote Sensing Group (RSG) at the University of Arizona. Improved over previous light-emitting diode based versions, these filter-based radiometers employ seven silicon detectors and one InGaAs detector covering a wavelength range of 400-1550 nm. They are temperature controlled and designed for greater stability and lower noise. The radiometer systems show signal-to-noise ratios of greater than 1000 for all eight channels at typical field calibration signal levels. Predeployment laboratory radiance calibrations using a 1 m spherical integrating source compare well with in situ field calibrations using the solar radiation based calibration method; all bands are within ±2.7% for the case tested.

  12. Internet-based calibration of a multifunction calibrator

    SciTech Connect

    BUNTING BACA,LISA A.; DUDA JR.,LEONARD E.; WALKER,RUSSELL M.; OLDHAM,NILE; PARKER,MARK

    2000-04-17

    A new way of providing calibration services is evolving which employs the Internet to expand present capabilities and make the calibration process more interactive. Sandia National Laboratories and the National Institute of Standards and Technology are collaborating to set up and demonstrate a remote calibration of multifunction calibrators using this Internet-based technique that is becoming known as e-calibration. This paper describes the measurement philosophy and the Internet resources that can provide real-time audio/video/data exchange, consultation and training, as well as web-accessible test procedures, software and calibration reports. The communication system utilizes commercial hardware and software that should be easy to integrate into most calibration laboratories.

  13. Internet-Based Calibration of a Multifunction Calibrator

    SciTech Connect

    BUNTING BACA,LISA A.; DUDA JR.,LEONARD E.; WALKER,RUSSELL M.; OLDHAM,NILE; PARKER,MARK

    2000-12-19

    A new way of providing calibration services is evolving which employs the Internet to expand present capabilities and make the calibration process more interactive. Sandia National Laboratories and the National Institute of Standards and Technology are collaborating to set up and demonstrate a remote calibration of multijunction calibrators using this Internet-based technique that is becoming known as e-calibration. This paper describes the measurement philosophy and the Internet resources that can provide real-time audio/video/data exchange, consultation and training, as well as web-accessible test procedures, software and calibration reports. The communication system utilizes commercial hardware and software that should be easy to integrate into most calibration laboratories.

  14. DIRBE External Calibrator (DEC)

    NASA Technical Reports Server (NTRS)

    Wyatt, Clair L.; Thurgood, V. Alan; Allred, Glenn D.

    1987-01-01

    Under NASA Contract No. NAS5-28185, the Center for Space Engineering at Utah State University has produced a calibration instrument for the Diffuse Infrared Background Experiment (DIRBE). DIRBE is one of the instruments aboard the Cosmic Background Experiment Observatory (COBE). The calibration instrument is referred to as the DEC (Dirbe External Calibrator). DEC produces a steerable, infrared beam of controlled spectral content and intensity and with selectable point source or diffuse source characteristics, that can be directed into the DIRBE to map fields and determine response characteristics. This report discusses the design of the DEC instrument, its operation and characteristics, and provides an analysis of the systems capabilities and performance.

  15. Sandia WIPP calibration traceability

    SciTech Connect

    Schuhen, M.D.; Dean, T.A.

    1996-05-01

    This report summarizes the work performed to establish calibration traceability for the instrumentation used by Sandia National Laboratories at the Waste Isolation Pilot Plant (WIPP) during testing from 1980-1985. Identifying the calibration traceability is an important part of establishing a pedigree for the data and is part of the qualification of existing data. In general, the requirement states that the calibration of Measuring and Test equipment must have a valid relationship to nationally recognized standards or the basis for the calibration must be documented. Sandia recognized that just establishing calibration traceability would not necessarily mean that all QA requirements were met during the certification of test instrumentation. To address this concern, the assessment was expanded to include various activities.

  16. Photometric calibrations for 21st century science

    SciTech Connect

    Kent, Stephen; Kaiser, Mary Elizabeth; Deustua, Susana E.; Smith, J.Allyn; Adelman, Saul; Allam, Sahar S.; Baptista, Brian; Bohlin, Ralph C.; Clem, James L.; Conley, Alex; Edelstein, Jerry; /UC, Berkeley, Space Sci. Dept. /NOAO, Tucson

    2009-02-01

    The answers to fundamental science questions in astrophysics, ranging from the history of the expansion of the universe to the sizes of nearby stars, hinge on our ability to make precise measurements of diverse astronomical objects. As our knowledge of the underlying physics of objects improves along with advances in detectors and instrumentation, the limits on our capability to extract science from measurements is set, not by our lack of understanding of the nature of these objects, but rather by the most mundane of all issues: the precision with which we can calibrate observations in physical units. In principle, photometric calibration is a solved problem - laboratory reference standards such as blackbody furnaces achieve precisions well in excess of those needed for astrophysics. In practice, however, transferring the calibration from these laboratory standards to astronomical objects of interest is far from trivial - the transfer must reach outside the atmosphere, extend over 4{pi} steradians of sky, cover a wide range of wavelengths, and span an enormous dynamic range in intensity. Virtually all spectrophotometric observations today are calibrated against one or more stellar reference sources, such as Vega, which are themselves tied back to laboratory standards in a variety of ways. This system's accuracy is not uniform. Selected regions of the electromagnetic spectrum are calibrated extremely well, but discontinuities of a few percent still exist, e.g., between the optical and infrared. Independently, model stellar atmospheres are used to calibrate the spectra of selected white dwarf stars, e.g. the HST system, but the ultimate accuracy of this system should be verified against laboratory sources. Our traditional standard star systems, while sufficient until now, need to be improved and extended in order to serve future astrophysics experiments. This white paper calls for a program to improve upon and expand the current networks of spectrophotometrically

  17. Evaluation of radionuclide dose-calibrator measurements

    SciTech Connect

    Paras, P.; Comer, F.M.; Demeis, F.; Coursey, B.M.; Calhoun, J.M.; Golas, D.B.

    1986-01-01

    Performance data for radionuclide dose calibrators, which are primarily ionization chambers, are scarce. Large deviations have occasionally been reported, particularly for low photon energies, i.e., emissions from /sup 201/Tl, /sup 133/Xe. The volunteer user program (QB series) of the College of American Pathologists (CAP) (laboratory intercomparison quality control), supported by the US National Bureau of Standards (NBS), for quality control of dose calibrators was suspended. The Atomic Industrial Forum (AIF) has a quality control program among radiopharmaceutical manufacturers but there is no user program in the US at this time, and the performance of dose calibrators in the field is not known. In addition, a number of professionals expressed a strong feeling for the continuation of the CAP program and the availability of standards for dose calibrators from NBS. The objective of this study is twofold: (a) to evaluate the accuracy of dose calibrator measurements for individual patient radioactivity administered doses, and (b) to provide certified sources of certain radionuclides to calibrate the instruments for these radionuclides.

  18. A new chapter in environmental sensing: The Open-Source Published Environmental Sensing (OPENS) laboratory

    NASA Astrophysics Data System (ADS)

    Selker, J. S.; Roques, C.; Higgins, C. W.; Good, S. P.; Hut, R.; Selker, A.

    2015-12-01

    The confluence of 3-Dimensional printing, low-cost solid-state-sensors, low-cost, low-power digital controllers (e.g., Arduinos); and open-source publishing (e.g., Github) is poised to transform environmental sensing. The Open-Source Published Environmental Sensing (OPENS) laboratory has launched and is available for all to use. OPENS combines cutting edge technologies and makes them available to the global environmental sensing community. OPENS includes a Maker lab space where people may collaborate in person or virtually via on-line forum for the publication and discussion of environmental sensing technology (Corvallis, Oregon, USA, please feel free to request a free reservation for space and equipment use). The physical lab houses a test-bed for sensors, as well as a complete classical machine shop, 3-D printers, electronics development benches, and workstations for code development. OPENS will provide a web-based formal publishing framework wherein global students and scientists can peer-review publish (with DOI) novel and evolutionary advancements in environmental sensor systems. This curated and peer-reviewed digital collection will include complete sets of "printable" parts and operating computer code for sensing systems. The physical lab will include all of the machines required to produce these sensing systems. These tools can be addressed in person or virtually, creating a truly global venue for advancement in monitoring earth's environment and agricultural systems. In this talk we will present an example of the process of design and publication the design and data from the OPENS-Permeameter. The publication includes 3-D printing code, Arduino (or other control/logging platform) operational code; sample data sets, and a full discussion of the design set in the scientific context of previous related devices. Editors for the peer-review process are currently sought - contact John.Selker@Oregonstate.edu or Clement.Roques@Oregonstate.edu.

  19. 10 CFR 32.102 - Schedule C-prototype tests for calibration or reference sources containing americium-241 or...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... sources containing americium-241 or radium-226. 32.102 Section 32.102 Energy NUCLEAR REGULATORY COMMISSION... americium-241 or radium-226. An applicant for a license under § 32.57 shall, for any type of source which is designed to contain more than 0.185 kilobecquerel (0.005 microcurie) of americium-241 or...

  20. 10 CFR 32.102 - Schedule C-prototype tests for calibration or reference sources containing americium-241 or...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... sources containing americium-241 or radium-226. 32.102 Section 32.102 Energy NUCLEAR REGULATORY COMMISSION... americium-241 or radium-226. An applicant for a license under § 32.57 shall, for any type of source which is designed to contain more than 0.185 kilobecquerel (0.005 microcurie) of americium-241 or...

  1. 10 CFR 32.102 - Schedule C-prototype tests for calibration or reference sources containing americium-241 or...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... sources containing americium-241 or radium-226. 32.102 Section 32.102 Energy NUCLEAR REGULATORY COMMISSION... americium-241 or radium-226. An applicant for a license under § 32.57 shall, for any type of source which is designed to contain more than 0.185 kilobecquerel (0.005 microcurie) of americium-241 or...

  2. 10 CFR 70.39 - Specific licenses for the manufacture or initial transfer of calibration or reference sources.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... radioactive material from the source shall be determined by measuring the radioactivity on the filter paper or by direct measurement of the radioactivity on the source following the dry wipe. (iii) Wet wipe test... be determined by measuring the radioactivity on the filter paper after it has dried or by...

  3. 10 CFR 70.39 - Specific licenses for the manufacture or initial transfer of calibration or reference sources.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... radioactive material from the source shall be determined by measuring the radioactivity on the filter paper or by direct measurement of the radioactivity on the source following the dry wipe. (iii) Wet wipe test... be determined by measuring the radioactivity on the filter paper after it has dried or by...

  4. 10 CFR 70.39 - Specific licenses for the manufacture or initial transfer of calibration or reference sources.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... radioactive material from the source shall be determined by measuring the radioactivity on the filter paper or by direct measurement of the radioactivity on the source following the dry wipe. (iii) Wet wipe test... be determined by measuring the radioactivity on the filter paper after it has dried or by...

  5. 10 CFR 70.39 - Specific licenses for the manufacture or initial transfer of calibration or reference sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... radioactive material from the source shall be determined by measuring the radioactivity on the filter paper or by direct measurement of the radioactivity on the source following the dry wipe. (iii) Wet wipe test... be determined by measuring the radioactivity on the filter paper after it has dried or by...

  6. 10 CFR 70.39 - Specific licenses for the manufacture or initial transfer of calibration or reference sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... radioactive material from the source shall be determined by measuring the radioactivity on the filter paper or by direct measurement of the radioactivity on the source following the dry wipe. (iii) Wet wipe test... be determined by measuring the radioactivity on the filter paper after it has dried or by...

  7. Calibration of acoustic transients.

    PubMed

    Burkard, Robert

    2006-05-26

    This article reviews the appropriate stimulus parameters (click duration, toneburst envelope) that should be used when eliciting auditory brainstem responses from mice. Equipment specifications required to calibrate these acoustic transients are discussed. Several methods of calibrating the level of acoustic transients are presented, including the measurement of peak equivalent sound pressure level (peSPL) and peak sound pressure level (pSPL). It is hoped that those who collect auditory brainstem response thresholds in mice will begin to use standardized methods of acoustic calibration, so that hearing thresholds across mouse strains obtained in different laboratories can more readily be compared.

  8. Lidar Calibration Centre

    NASA Astrophysics Data System (ADS)

    Pappalardo, Gelsomina; Freudenthaler, Volker; Nicolae, Doina; Mona, Lucia; Belegante, Livio; D'Amico, Giuseppe

    2016-06-01

    This paper presents the newly established Lidar Calibration Centre, a distributed infrastructure in Europe, whose goal is to offer services for complete characterization and calibration of lidars and ceilometers. Mobile reference lidars, laboratories for testing and characterization of optics and electronics, facilities for inspection and debugging of instruments, as well as for training in good practices are open to users from the scientific community, operational services and private sector. The Lidar Calibration Centre offers support for trans-national access through the EC HORIZON2020 project ACTRIS-2.

  9. DOE radiological calibrations intercomparison program: Results of fiscal year 1986

    SciTech Connect

    Cummings, F.M.; Roberson, P.L.; McDonald, J.C.

    1987-05-01

    The Department of Energy Radiological Calibration Intercomparison Program was initiated in January 1986, under the research portion of the DOE Laboratory Accreditation Program. The program operates via the exchange of transfer standards, consisting of instrument sets and standard secondary beta sources. There are two instrument sets and the scheduled use has been staggered such that one set is available for use during each month. One set of secondary standard beta sources is available for use bimonthly. During the 1986 fiscal year, five laboratories used the instrument sets and three laboratories used the beta source set. Results were reported for all the measurements. The average and one standard deviation of the ratios of participant results to Pacific Northwest Laboratory calibration values were 1.12 +- 0.17 for gamma measurements. Those ratios for the gamma measurements varied from 0.98 to 3.06. The larger differences of results from measurements performed at two facilities were directly attributable to unfamiliarity with the intercomparison instruments. The average and one standard deviation of the ratios of participant results to PNL calibration values obtained using the secondary /sup 90/Sr beta source was 1.02 +- 0.05, which is well within measurement uncertainties. The one participant who performed measurements using /sup 147/Pm and /sup 204/Tl sources obtained ratios of 0.68 and 1.11, respectively. No measurements were performed using neutron or x-ray sources.

  10. Laboratory Calibration of X-ray Velocimeters for Radiation Driven Winds and Outflows Surrounding X-ray Binaries and Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Brown, Gregory V.; Beiersdorfer, P.; Graf, A.; Hell, N.; Liedahl, D.; Magee, E. W.; Träbert, E.; Beilmann, C.; Bernitt, S.; Crespo-Lopez-Urritiua, J.; Eberle, S.; Kubicek, K.; Mäckel, V.; Rudolph, J.; Steinbrügge, R.; Ullrich, J.; Kelley, R. L.; Kilbourne, C. A.; Leutenegger, M.; Porter, F. S.; Rasmussen, A.; Simon, M.; Epp, S.

    2011-09-01

    High resolution measurements of X-ray absorption and fluorescence by radiation driven winds and outflows surrounding X-ray binaries and AGN provide a powerful means for measuring wind velocities. The accuracy of these X-ray velocimeters is limited by the accuracy of atomic data. For example, in the case of the high mass X-ray binary Vela X-1 the uncertainty in the calculated transition wavelengths of the K alpha lines produced by photoionization and photoexcitation of Si L-shell ions is comparable to the likely Doppler shifts, making it impossible to determine a reliable velocity. Similar problems also exist in the case of absorption of X-rays by M-shell Fe ions, which produces in some AGN the so-called unresolved transition array across the 15-17 angstrom band. In this case, there is a 15-45 milliangstrom variation among different wavelength calculations. The uncertainty in the calculations makes it impossible to reliably determine the true velocity structure of the outflow, and in turn, prevents a reliable determination of the mass-loss rate of the AGN. We present results of a recent series of laboratory experiments conducted using an electron beam ion trap coupled with the LCLS X-ray free electron laser and the BESSY-II synchrotron and designed to calibrate the velocimeters provided by high resolution instruments on Chandra and XMM-Newton. We also present results of resonant photoexcitation measurements of the transition wavelength of an Fe XVI satellite line 'coincident' with the 2p-3d Fe XVII line 3D at 15.26 angstroms. This line has never been resolved using emission spectroscopy and its measurement confirms the intensity of line 3D is sensitive to the relative abundance of Fe XVI and XVII and thus temperature. Work at LLNL was performed under the auspices of DOE under contract DE-AC53-07NA27344 and supported by NASA's APRA program.

  11. PERSONALISED BODY COUNTER CALIBRATION USING ANTHROPOMETRIC PARAMETERS.

    PubMed

    Pölz, S; Breustedt, B

    2016-09-01

    Current calibration methods for body counting offer personalisation for lung counting predominantly with respect to ratios of body mass and height. Chest wall thickness is used as an intermediate parameter. This work revises and extends these methods using a series of computational phantoms derived from medical imaging data in combination with radiation transport simulation and statistical analysis. As an example, the method is applied to the calibration of the In Vivo Measurement Laboratory (IVM) at Karlsruhe Institute of Technology (KIT) comprising four high-purity germanium detectors in two partial body measurement set-ups. The Monte Carlo N-Particle (MCNP) transport code and the Extended Cardiac-Torso (XCAT) phantom series have been used. Analysis of the computed sample data consisting of 18 anthropometric parameters and calibration factors generated from 26 photon sources for each of the 30 phantoms reveals the significance of those parameters required for producing an accurate estimate of the calibration function. Body circumferences related to the source location perform best in the example, while parameters related to body mass show comparable but lower performances, and those related to body height and other lengths exhibit low performances. In conclusion, it is possible to give more accurate estimates of calibration factors using this proposed approach including estimates of uncertainties related to interindividual anatomical variation of the target population. PMID:26396263

  12. Effect of the solenoid in various conditions of the laser ion source at Brookhaven National Laboratory.

    PubMed

    Ikeda, S; Kumaki, M; Kanesue, T; Okamura, M

    2016-02-01

    In the laser ion source (LIS) at the Brookhaven National Laboratory (BNL), a solenoid is used to guide the laser ablation plasma and modulate the extracted beam current. Many types of ion species are guided. In some cases, the plasma plume is injected into the solenoid away from the solenoidal axis. To investigate the effects of the solenoid on the beam extracted from the plasma that has different properties, the beam current was measured in the setup of the LIS at the BNL. The beam current of Li, Al, Si, Fe, and Au increased when the magnetic field was applied. For most of the species the peak current and the total charge within a single beam pulse increased around 10 times with a magnetic field less than 100 G. In addition, for some species the rate of increase of the peak currents became smaller when the magnetic flux densities were larger than certain values depending on the species. In this case, the current waveforms were distorted. At the same magnetic field value, the field was more effective on lighter species than on heavier ones. When plasma was injected offset from the axis of the solenoid, peak current and total charge became half of those without offset. The experimental data are useful for the operation of the LIS at the BNL. PMID:26931976

  13. Effect of the solenoid in various conditions of the laser ion source at Brookhaven National Laboratory.

    PubMed

    Ikeda, S; Kumaki, M; Kanesue, T; Okamura, M

    2016-02-01

    In the laser ion source (LIS) at the Brookhaven National Laboratory (BNL), a solenoid is used to guide the laser ablation plasma and modulate the extracted beam current. Many types of ion species are guided. In some cases, the plasma plume is injected into the solenoid away from the solenoidal axis. To investigate the effects of the solenoid on the beam extracted from the plasma that has different properties, the beam current was measured in the setup of the LIS at the BNL. The beam current of Li, Al, Si, Fe, and Au increased when the magnetic field was applied. For most of the species the peak current and the total charge within a single beam pulse increased around 10 times with a magnetic field less than 100 G. In addition, for some species the rate of increase of the peak currents became smaller when the magnetic flux densities were larger than certain values depending on the species. In this case, the current waveforms were distorted. At the same magnetic field value, the field was more effective on lighter species than on heavier ones. When plasma was injected offset from the axis of the solenoid, peak current and total charge became half of those without offset. The experimental data are useful for the operation of the LIS at the BNL.

  14. New developments and applications of intense pulsed radiation sources at Sandia National Laboratories

    SciTech Connect

    Cook, D.

    1998-02-01

    In the past thirty-six months, tremendous strides have been made in x-ray production using high-current z-pinches. Today, the x-ray energy (1.9 MJ) and power (200 TW) output of the Z accelerator (formerly PBFA-II) is the largest available in the laboratory. These z-pinch x-ray sources are being developed for research into the physics of high energy density plasmas of interest in weapon behavior and in inertial confinement fusion. Beyond the Z accelerator current of 20 MA, an extrapolation to the X-1 accelerator level of 60 MA may have the potential to drive high-yield ICF reactions at affordable cost if several challenging technical problems can be overcome. New developments have also taken place at Sandia in the area of high current, mm-diameter electron beams for advanced hydrodynamic radiography. On SABRE, x-ray spot diameters were less than 2 mm with a dose of 100 R at 1 meter in a 40 ns pulse.

  15. The low-energy toroidal grating monochromator beamline at the synchrotron radiation source at Daresbury Laboratory

    SciTech Connect

    Hoyland, M.A. ); Harrington, J.Q.; Weston, M.I. )

    1992-01-01

    The bending magnet beam line 1.2 low-energy toroidal grating monochromator of the synchrotron radiation source (SRS) at Daresbury Laboratory, was designed{sup 1} to deliver moderately high fluxes ({similar to} 5 {times} 10{sup 11} photons s{sup {minus}1}), of linearly polarized, medium resolution ({similar to}0.2 eV) radiation in the energy range 5--85 eV. The colinear optical system utilizes platinum-coated silicon-carbide mirrors to focus the broad-band radiation emergent from the SRS at the entrance slits of the three grating monochromator. A single ellipsoidal mirror is then used to doubly focus the desired narrow-band radiation at the sample position. The colinear arrangement of the optical elements ensures that the radiation at the sample point is strongly horizontally plane polarized (estimated to be of order 90%). The entire system has been the subject of detailed analyses using the raytracing program SHADOW,{sup 2} and standard optical theory. These calculations have been compared with experimental determinations of photon flux outputs and resolution measurements.

  16. An open-source, extensible system for laboratory timing and control

    NASA Astrophysics Data System (ADS)

    Gaskell, Peter E.; Thorn, Jeremy J.; Alba, Sequoia; Steck, Daniel A.

    2009-11-01

    We describe a simple system for timing and control, which provides control of analog, digital, and radio-frequency signals. Our system differs from most common laboratory setups in that it is open source, built from off-the-shelf components, synchronized to a common and accurate clock, and connected over an Ethernet network. A simple bus architecture facilitates creating new and specialized devices with only moderate experience in circuit design. Each device operates independently, requiring only an Ethernet network connection to the controlling computer, a clock signal, and a trigger signal. This makes the system highly robust and scalable. The devices can all be connected to a single external clock, allowing synchronous operation of a large number of devices for situations requiring precise timing of many parallel control and acquisition channels. Provided an accurate enough clock, these devices are capable of triggering events separated by one day with near-microsecond precision. We have achieved precisions of ˜0.1 ppb (parts per 109) over 16 s.

  17. Collecting data in the home laboratory: evolution of X-ray sources, detectors and working practices

    SciTech Connect

    Skarzynski, Tadeusz

    2013-07-01

    Recent developments in X-ray crystallographic hardware related to structural biology research are presented and discussed. While the majority of macromolecular X-ray data are currently collected using highly efficient beamlines at an ever-increasing number of synchrotrons, there is still a need for high-performance reliable systems for in-house experiments. In addition to crystal screening and optimization of data-collection parameters before a synchrotron trip, the home system allows the collection of data as soon as the crystals are produced to obtain the solution of novel structures, especially by the molecular-replacement method, and is invaluable in achieving the quick turnover that is often required for ligand-binding studies in the pharmaceutical industry. There has been a continuous evolution of X-ray sources, detectors and software developed for in-house use in recent years and a diverse range of tools for structural biology laboratories are available. An overview of the main directions of these developments and examples of specific solutions available to the macromolecular crystallography community are presented in this paper, showing that data collection ‘at home’ is still an attractive proposition complementing the use of synchrotron beamlines.

  18. Beowulf - Beta-Gamma Detector Calibration Graphical User Interface

    SciTech Connect

    McIntyre, Justin I.; Schrom, Brian T.; Cooper, Matthew W.; Haas, Derek A.; Hayes, James C.

    2009-09-21

    Pacific Northwest National Laboratory (PNNL) has demonstrated significant advancement in using beta-gamma coincidence detectors to detect a wide range of radioxenon isotopes. To obtain accurate activities with the detector it must be properly calibrated by measuring a series of calibration gas samples. The data is analyzed to create the calibration block used in the International Monitoring System file format. Doing the calibration manually has proven to be tedious and prone to errors, requiring a high degree of expertise. The Beowulf graphical user interface (GUI) is a software application that encompasses several components of the calibration task and generates a calibration block, as well as, a detailed report describing the specific calibration process used. This additional document can be used as a Quality assurance certificate to assist in auditing the calibration. This paper consists of two sections. Section 1 will describe the capabilities of Beowulf and section 2 will be a representative report generated or the 137Cs calibration and quality assurance source.

  19. Sources of Variability in Chlorophyll Analysis by Fluorometry and High-Performance Liquid Chromatography in a SIMBIOS Inter-Calibration Exercise

    NASA Technical Reports Server (NTRS)

    VanHeukelem, Laurie; Thomas, Crystal S.; Gilbert, Patricia M.; Fargion, Giulietta S. (Editor); McClain, Charles R. (Editor)

    2002-01-01

    The purpose of this technical report is to provide current documentation of the Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project activities, NASA Research Announcement (NRA) research status, satellite data processing, data product validation, and field calibration. This documentation is necessary to ensure that critical information is related to the scientific community and NASA management. This critical information includes the technical difficulties and challenges of validating and combining ocean color data from an array of independent satellite systems to form consistent and accurate global bio-optical time series products. This technical report is not meant as a substitute for scientific literature. Instead, it will provide a ready and responsive vehicle for the multitude of technical reports issued by an operational project. This particular document focus on the variability in chlorophyll pigment measurements resulting from differences in methodologies and laboratories conducting the pigment analysis.

  20. Pore-space alteration in source rock (shales) during hydrocarbons generation: laboratory experiment

    NASA Astrophysics Data System (ADS)

    Giliazetdinova, D. R.; Korost, D. V.; Nadezhkin, D. V.

    2013-12-01

    Hydrocarbons (HC) are generated from solid organic matter (kerogen) due to thermocatalytic reactions. The rate of such reactions shows direct correlation with temperature and depends on the depth of source rock burial. Burial of sedimentary rock is also inevitably accompanied by its structural alteration owing to compaction, dehydration and re-crystallization. Processes of HC generation, primary migration and structural changes are inaccessible for direct observation in nature, but they can be studied in laboratory experiments. Experiment was carried out with a clayey-carbonate rock sample of the Domanik Horizon taken from boreholes drilled in the northeastern part of the south Tatar arch. The rock chosen fits the very essential requirements - high organic matter content and its low metamorphic grade. Our work aimed at laboratory modeling of HC generation in an undisturbed rock sample by its heating in nitrogen atmosphere based on a specified temperature regime and monitoring alterations in the pore space structure. Observations were carried out with a SkyScan-1172 X-ray microtomography scanner (resulting scan resolution of 1 μm). A cylinder, 44 mm in diameter, was prepared from the rock sample for the pyrolitic and microtomographic analyses. Scanning procedures were carried out in 5 runs. Temperature interval for each run had to match the most important stage of HC generation in the source rock, namely: (1) original structure; (2) 100-300°C - discharge of free and adsorbed HC and water; (3) 300-400°C - initial stage of HC formation owing to high-temperature pyrolysis of the solid organic matter and discharge of the chemically bound water; (4) 400-470°C - temperature interval fitting the most intense stage of HC formation; (5) 470-510°C - final stage of HC formation. Maximum sample heating in the experiment was determined as temperature of the onset of active decomposition of carbonates, i.e., in essence, irreversible metamorphism of the rock. Additional

  1. Recommendations following a multi-laboratory comparison of microbial source tracking methods

    EPA Science Inventory

    Microbial source tracking (MST) methods are under development to provide resource managers with tools to identify sources of fecal contamination in water. Some of the most promising methods currently under development were recently evaluated in the Source Identification Protocol ...

  2. Software For Calibration Of Polarimetric SAR Data

    NASA Technical Reports Server (NTRS)

    Van Zyl, Jakob; Zebker, Howard; Freeman, Anthony; Holt, John; Dubois, Pascale; Chapman, Bruce

    1994-01-01

    POLCAL (Polarimetric Radar Calibration) software tool intended to assist in calibration of synthetic-aperture radar (SAR) systems. In particular, calibrates Stokes-matrix-format data produced as standard product by NASA/Jet Propulsion Laboratory (JPL) airborne imaging synthetic aperture radar (AIRSAR). Version 4.0 of POLCAL is upgrade of version 2.0. New options include automatic absolute calibration of 89/90 data, distributed-target analysis, calibration of nearby scenes with corner reflectors, altitude or roll-angle corrections, and calibration of errors introduced by known topography. Reduces crosstalk and corrects phase calibration without use of ground calibration equipment. Written in FORTRAN 77.

  3. Source Tracking of Nitrous Oxide using A Quantum Cascade Laser System in the Field and Laboratory Environments

    EPA Science Inventory

    Nitrous oxide is an important greenhouse gas and ozone depleting substance. Nitrification and denitrification are two major biological pathways that are responsible for soil emissions of N2O. However, source tracking of in-situ or laboratory N2O production is still challenging to...

  4. Limits on the release of Rb isotopes from a zeolite based 83mKr calibration source for the XENON project

    NASA Astrophysics Data System (ADS)

    Hannen, V.; Aprile, E.; Arneodo, F.; Baudis, L.; Beck, M.; Bokeloh, K.; Ferella, A. D.; Giboni, K.; Lang, R. F.; Lebeda, O.; Ortjohann, H.-W.; Schumann, M.; Spalek, A.; Venos, D.; Weinheimer, C.

    2011-10-01

    The isomer 83mKr with its half-life of 1.83 h is an ideal calibration source for a liquid noble gas dark matter experiment like the XENON project. However, the risk of contamination of the detector with traces of the much longer lived mother isotope 83Rb(T½ = 86.2 d) has to be ruled out. In this work the release of 83Rb atoms from a 1.8 MBq 83Rb source embedded in zeolite beads has been investigated. To do so, a cryogenic trap has been connected to the source for about 10 days, after which it was removed and probed for the strongest 83Rbγ-rays with an ultra-sensitive Germanium detector. No signal has been found. The corresponding upper limit on the released 83Rb activity means that the investigated type of source can be used in the XENON project and similar low-background experiments as 83mKr generator without a significant risk of contaminating the detector. The measurements also allow to set upper limits on the possible release of the isotopes 84Rb and 86Rb, traces of which were created alongside the production of 83Rb at the Rez cyclotron.

  5. Scaling Transition in Earthquake Sources: A Possible Link Between Seismic and Laboratory Measurements

    NASA Astrophysics Data System (ADS)

    Malagnini, Luca; Mayeda, Kevin; Nielsen, Stefan; Yoo, Seung-Hoon; Munafo', Irene; Rawles, Christopher; Boschi, Enzo

    2014-10-01

    We estimate the corner frequencies of 20 crustal seismic events from mainshock-aftershock sequences in different tectonic environments (mainshocks 5.7 < M W < 7.6) using the well-established seismic coda ratio technique ( Mayeda et al. in Geophys Res Lett 34:L11303, 2007; Mayeda and Malagnini in Geophys Res Lett, 2010), which provides optimal stability and does not require path or site corrections. For each sequence, we assumed the Brune source model and estimated all the events' corner frequencies and associated apparent stresses following the MDAC spectral formulation of Walter and Taylor (A revised magnitude and distance amplitude correction (MDAC2) procedure for regional seismic discriminants, 2001), which allows for the possibility of non-self-similar source scaling. Within each sequence, we observe a systematic deviation from the self-similar line, all data being rather compatible with , where ɛ > 0 ( Kanamori and Rivera in Bull Seismol Soc Am 94:314-319, 2004). The deviation from a strict self-similar behavior within each earthquake sequence of our collection is indicated by a systematic increase in the estimated average static stress drop and apparent stress with increasing seismic moment (moment magnitude). Our favored physical interpretation for the increased apparent stress with earthquake size is a progressive frictional weakening for increasing seismic slip, in agreement with recent results obtained in laboratory experiments performed on state-of-the-art apparatuses at slip rates of the order of 1 m/s or larger. At smaller magnitudes ( M W < 5.5), the overall data set is characterized by a variability in apparent stress of almost three orders of magnitude, mostly from the scatter observed in strike-slip sequences. Larger events ( M W > 5.5) show much less variability: about one order of magnitude. It appears that the apparent stress (and static stress drop) does not grow indefinitely at larger magnitudes: for example, in the case of the Chi

  6. Instrument calibration.

    PubMed

    Padden, Harvey

    2002-05-01

    The main thing to remember is that measurement uncertainty must encompass everything from NIST to the final laboratory result. Every source of error along the way must be accounted for. Our vendors do much of it for us, but we must make sure they are doing their job properly. We must make certain our vendors have performed rigorous uncertainty analyses and are performing in accordance with them. ISO 9001-2000 and 17,025 accreditations can eventually help offer us assurance in this area. PMID:12037906

  7. Water Quality & Pollutant Source Monitoring: Field and Laboratory Procedures. Training Manual.

    ERIC Educational Resources Information Center

    Office of Water Program Operations (EPA), Cincinnati, OH. National Training and Operational Technology Center.

    This training manual presents material on techniques and instrumentation used to develop data in field monitoring programs and related laboratory operations concerned with water quality and pollution monitoring. Topics include: collection and handling of samples; bacteriological, biological, and chemical field and laboratory methods; field…

  8. Calibration and operational data for a compact photodiode detector useful for monitoring the location of moving sources of positron emitting radioisotopes

    SciTech Connect

    Marsland, M. G.; Dehnel, M. P.; Theroux, J.; Christensen, T.; Hollinger, C.; Johansson, S.; Rajander, J.; Solin, O.; Stewart, T. M.

    2013-04-19

    D-Pace has developed a compact cost-effective gamma detector system based on technology licensed from TRIUMF. These photodiode detectors are convenient for detecting the presence of positron emitting radioisotopes, particularly for the case of transport of radioisotopes from a PET cyclotron to hotlab, or from one location to another in an automated radiochemistry processing unit. This paper describes recent calibration experiments undertaken at the Turku PET Centre for stationary and moving sources of F18 and C11 in standard setups. The practical diagnostic utility of using several of these devices to track the transport of radioisotopes from the cyclotron to hotlab is illustrated. For example, such a detector system provides: a semi-quantitative indication of total activity, speed of transport, location of any activity lost en route and effectiveness of follow-up system flushes, a means of identifying bolus break-up, feedback useful for deciding when to change out tubing.

  9. Calibration and operational data for a compact photodiode detector useful for monitoring the location of moving sources of positron emitting radioisotopes

    NASA Astrophysics Data System (ADS)

    Marsland, M. G.; Dehnel, M. P.; Johansson, S.; Rajander, J.; Solin, O.; Theroux, J.; Stewart, T. M.; Christensen, T.; Hollinger, C.

    2013-04-01

    D-Pace has developed a compact cost-effective gamma detector system based on technology licensed from TRIUMF [1]. These photodiode detectors are convenient for detecting the presence of positron emitting radioisotopes, particularly for the case of transport of radioisotopes from a PET cyclotron to hotlab, or from one location to another in an automated radiochemistry processing unit. This paper describes recent calibration experiments undertaken at the Turku PET Centre for stationary and moving sources of F18 and C11 in standard setups. The practical diagnostic utility of using several of these devices to track the transport of radioisotopes from the cyclotron to hotlab is illustrated. For example, such a detector system provides: a semi-quantitative indication of total activity, speed of transport, location of any activity lost en route and effectiveness of follow-up system flushes, a means of identifying bolus break-up, feedback useful for deciding when to change out tubing.

  10. Calibration of neutron albedo dosemeters.

    PubMed

    Schwartz, R B; Eisenhauer, C M

    2002-01-01

    It is shown that by calibrating neutron albedo dosemeters under the proper conditions, two complicating effects will essentially cancel out, allowing accurate calibrations with no need for explicit corrections. The 'proper conditions' are: a large room (> or = 8 m on a side). use of a D2O moderated 252Cf source, and a source-to-phantom calibration distance of approximately 70 cm. PMID:12212898

  11. Calibrated Properties Model

    SciTech Connect

    C.F. Ahlers, H.H. Liu

    2001-12-18

    The purpose of this Analysis/Model Report (AMR) is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Yucca Mountain Site Characterization Project (YMP). This work was performed in accordance with the AMR Development Plan for U0035 Calibrated Properties Model REV00 (CRWMS M&O 1999c). These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, drift-scale and mountain-scale coupled-processes models, and Total System Performance Assessment (TSPA) models as well as Performance Assessment (PA) and other participating national laboratories and government agencies. These process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions.

  12. Calibrated Properties Model

    SciTech Connect

    C. Ahlers; H. Liu

    2000-03-12

    The purpose of this Analysis/Model Report (AMR) is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Yucca Mountain Site Characterization Project (YMP). This work was performed in accordance with the ''AMR Development Plan for U0035 Calibrated Properties Model REV00. These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, drift-scale and mountain-scale coupled-processes models, and Total System Performance Assessment (TSPA) models as well as Performance Assessment (PA) and other participating national laboratories and government agencies. These process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions.

  13. Gemini facility calibration unit

    NASA Astrophysics Data System (ADS)

    Ramsay-Howat, Suzanne K.; Harris, John W.; Gostick, David C.; Laidlaw, Ken; Kidd, Norrie; Strachan, Mel; Wilson, Ken

    2000-08-01

    High-quality, efficient calibration instruments is a pre- requisite for the modern observatory. Each of the Gemini telescopes will be equipped with identical facility calibration units (GCALs) designed to provide wavelength and flat-field calibrations for the suite of instruments. The broad range of instrumentation planned for the telescopes heavily constrains the design of GCAL. Short calibration exposures are required over wavelengths from 0.3micrometers to 5micrometers , field sizes up to 7 arcminutes and spectral resolution from R-5 to 50,000. The output from GCAL must mimic the f-16 beam of the telescope and provide a uniform illumination of the focal plane. The calibration units are mounted on the Gemini Instrument Support Structure, two meters from the focal pane, necessitating the use of large optical components. We will discuss the opto-mechanical design of the Gemini calibration unit, with reference to those feature which allow these stringent requirements to be met. A novel reflector/diffuser unit replaces the integration sphere more normally found in calibration systems. The efficiency of this system is an order of magnitude greater than for an integration sphere. A system of two off-axis mirrors reproduces the telescope pupil and provides the 7 foot focal plane. The results of laboratory test of the uniformity and throughput of the GCAL will be presented.

  14. The Calibration Reference Data System

    NASA Astrophysics Data System (ADS)

    Greenfield, P.; Miller, T.

    2016-07-01

    We describe a software architecture and implementation for using rules to determine which calibration files are appropriate for calibrating a given observation. This new system, the Calibration Reference Data System (CRDS), replaces what had been previously used for the Hubble Space Telescope (HST) calibration pipelines, the Calibration Database System (CDBS). CRDS will be used for the James Webb Space Telescope (JWST) calibration pipelines, and is currently being used for HST calibration pipelines. CRDS can be easily generalized for use in similar applications that need a rules-based system for selecting the appropriate item for a given dataset; we give some examples of such generalizations that will likely be used for JWST. The core functionality of the Calibration Reference Data System is available under an Open Source license. CRDS is briefly contrasted with a sampling of other similar systems used at other observatories.

  15. Multiple species beam production on laser ion source for electron beam ion source in Brookhaven National Laboratory

    SciTech Connect

    Sekine, M.; Ikeda, S.; Hayashizaki, N.; Kanesue, T.; Okamura, M.

    2014-02-15

    Extracted ion beams from the test laser ion source (LIS) were transported through a test beam transport line which is almost identical to the actual primary beam transport in the current electron beam ion source apparatus. The tested species were C, Al, Si, Cr, Fe, Cu, Ag, Ta, and Au. The all measured beam currents fulfilled the requirements. However, in the case of light mass ions, the recorded emittance shapes have larger aberrations and the RMS values are higher than 0.06 π mm mrad, which is the design goal. Since we have margin to enhance the beam current, if we then allow some beam losses at the injection point, the number of the single charged ions within the acceptance can be supplied. For heaver ions like Ag, Ta, and Au, the LIS showed very good performance.

  16. First beam measurements on the vessel for extraction and source plasma analyses (VESPA) at the Rutherford Appleton Laboratory (RAL)

    SciTech Connect

    Lawrie, Scott R.; Faircloth, Daniel C.; Letchford, Alan P.; Perkins, Mike; Whitehead, Mark O.; Wood, Trevor

    2015-04-08

    In order to facilitate the testing of advanced H{sup −} ion sources for the ISIS and Front End Test Stand (FETS) facilities at the Rutherford Appleton Laboratory (RAL), a Vessel for Extraction and Source Plasma Analyses (VESPA) has been constructed. This will perform the first detailed plasma measurements on the ISIS Penning-type H{sup −} ion source using emission spectroscopic techniques. In addition, the 30-year-old extraction optics are re-designed from the ground up in order to fully transport the beam. Using multiple beam and plasma diagnostics devices, the ultimate aim is improve H{sup −} production efficiency and subsequent transport for either long-term ISIS user operations or high power FETS requirements. The VESPA will also accommodate and test a new scaled-up Penning H{sup −} source design. This paper details the VESPA design, construction and commissioning, as well as initial beam and spectroscopy results.

  17. First beam measurements on the vessel for extraction and source plasma analyses (VESPA) at the Rutherford Appleton Laboratory (RAL)

    NASA Astrophysics Data System (ADS)

    Lawrie, Scott R.; Faircloth, Daniel C.; Letchford, Alan P.; Perkins, Mike; Whitehead, Mark O.; Wood, Trevor

    2015-04-01

    In order to facilitate the testing of advanced H- ion sources for the ISIS and Front End Test Stand (FETS) facilities at the Rutherford Appleton Laboratory (RAL), a Vessel for Extraction and Source Plasma Analyses (VESPA) has been constructed. This will perform the first detailed plasma measurements on the ISIS Penning-type H- ion source using emission spectroscopic techniques. In addition, the 30-year-old extraction optics are re-designed from the ground up in order to fully transport the beam. Using multiple beam and plasma diagnostics devices, the ultimate aim is improve H- production efficiency and subsequent transport for either long-term ISIS user operations or high power FETS requirements. The VESPA will also accommodate and test a new scaled-up Penning H- source design. This paper details the VESPA design, construction and commissioning, as well as initial beam and spectroscopy results.

  18. Investigation of ISIS and Brookhaven National Laboratory ion source electrodes after extended operationa)

    NASA Astrophysics Data System (ADS)

    Lettry, J.; Alessi, J.; Faircloth, D.; Gerardin, A.; Kalvas, T.; Pereira, H.; Sgobba, S.

    2012-02-01

    Linac4 accelerator of Centre Européen de Recherches Nucléaires is under construction and a RF-driven H- ion source is being developed. The beam current requirement for Linac4 is very challenging: 80 mA must be provided. Cesiated plasma discharge ion sources such as Penning or magnetron sources are also potential candidates. Accelerator ion sources must achieve typical reliability figures of 95% and above. Investigating and understanding the underlying mechanisms involved with source failure or ageing is critical when selecting the ion source technology. Plasma discharge driven surface ion sources rely on molybdenum cathodes. Deformation of the cathode surfaces is visible after extended operation periods. A metallurgical investigation of an ISIS ion source is presented. The origin of the deformation is twofold: Molybdenum sputtering by cesium ions digs few tenths of mm cavities while a growth of molybdenum is observed in the immediate vicinity. The molybdenum growth under hydrogen atmosphere is hard and loosely bound to the bulk. It is, therefore, likely to peel off and be transported within the plasma volume. The observation of the cathode, anode, and extraction electrodes of the magnetron source operated at BNL for two years are presented. A beam simulation of H-, electrons, and Cs- ions was performed with the IBSimu code package to qualitatively explain the observations. This paper describes the operation conditions of the ion sources and discusses the metallurgical analysis and beam simulation results.

  19. Investigation of ISIS and Brookhaven National Laboratory ion source electrodes after extended operation

    SciTech Connect

    Lettry J.; Alessi J.; Faircloth, D.; Gerardin, A.; Kalvas, T.; Pereira, H.; Sgobba, S.

    2012-02-23

    Linac4 accelerator of Centre Europeen de Recherches Nucleaires is under construction and a RF-driven H{sup -} ion source is being developed. The beam current requirement for Linac4 is very challenging: 80 mA must be provided. Cesiated plasma discharge ion sources such as Penning or magnetron sources are also potential candidates. Accelerator ion sources must achieve typical reliability figures of 95% and above. Investigating and understanding the underlying mechanisms involved with source failure or ageing is critical when selecting the ion source technology. Plasma discharge driven surface ion sources rely on molybdenum cathodes. Deformation of the cathode surfaces is visible after extended operation periods. A metallurgical investigation of an ISIS ion source is presented. The origin of the deformation is twofold: Molybdenum sputtering by cesium ions digs few tenths of mm cavities while a growth of molybdenum is observed in the immediate vicinity. The molybdenum growth under hydrogen atmosphere is hard and loosely bound to the bulk. It is, therefore, likely to peel off and be transported within the plasma volume. The observation of the cathode, anode, and extraction electrodes of the magnetron source operated at BNL for two years are presented. A beam simulation of H{sup -}, electrons, and Cs{sup -} ions was performed with the IBSimu code package to qualitatively explain the observations. This paper describes the operation conditions of the ion sources and discusses the metallurgical analysis and beam simulation results.

  20. Investigation of ISIS and Brookhaven National Laboratory ion source electrodes after extended operation.

    PubMed

    Lettry, J; Alessi, J; Faircloth, D; Gerardin, A; Kalvas, T; Pereira, H; Sgobba, S

    2012-02-01

    Linac4 accelerator of Centre Européen de Recherches Nucléaires is under construction and a RF-driven H(-) ion source is being developed. The beam current requirement for Linac4 is very challenging: 80 mA must be provided. Cesiated plasma discharge ion sources such as Penning or magnetron sources are also potential candidates. Accelerator ion sources must achieve typical reliability figures of 95% and above. Investigating and understanding the underlying mechanisms involved with source failure or ageing is critical when selecting the ion source technology. Plasma discharge driven surface ion sources rely on molybdenum cathodes. Deformation of the cathode surfaces is visible after extended operation periods. A metallurgical investigation of an ISIS ion source is presented. The origin of the deformation is twofold: Molybdenum sputtering by cesium ions digs few tenths of mm cavities while a growth of molybdenum is observed in the immediate vicinity. The molybdenum growth under hydrogen atmosphere is hard and loosely bound to the bulk. It is, therefore, likely to peel off and be transported within the plasma volume. The observation of the cathode, anode, and extraction electrodes of the magnetron source operated at BNL for two years are presented. A beam simulation of H(-), electrons, and Cs(-) ions was performed with the IBSimu code package to qualitatively explain the observations. This paper describes the operation conditions of the ion sources and discusses the metallurgical analysis and beam simulation results.

  1. Investigation of ISIS and Brookhaven National Laboratory ion source electrodes after extended operation

    SciTech Connect

    Lettry, J.; Gerardin, A.; Pereira, H.; Sgobba, S.; Alessi, J.; Faircloth, D.; Kalvas, T.

    2012-02-15

    Linac4 accelerator of Centre Europeen de Recherches Nucleaires is under construction and a RF-driven H{sup -} ion source is being developed. The beam current requirement for Linac4 is very challenging: 80 mA must be provided. Cesiated plasma discharge ion sources such as Penning or magnetron sources are also potential candidates. Accelerator ion sources must achieve typical reliability figures of 95% and above. Investigating and understanding the underlying mechanisms involved with source failure or ageing is critical when selecting the ion source technology. Plasma discharge driven surface ion sources rely on molybdenum cathodes. Deformation of the cathode surfaces is visible after extended operation periods. A metallurgical investigation of an ISIS ion source is presented. The origin of the deformation is twofold: Molybdenum sputtering by cesium ions digs few tenths of mm cavities while a growth of molybdenum is observed in the immediate vicinity. The molybdenum growth under hydrogen atmosphere is hard and loosely bound to the bulk. It is, therefore, likely to peel off and be transported within the plasma volume. The observation of the cathode, anode, and extraction electrodes of the magnetron source operated at BNL for two years are presented. A beam simulation of H{sup -}, electrons, and Cs{sup -} ions was performed with the IBSimu code package to qualitatively explain the observations. This paper describes the operation conditions of the ion sources and discusses the metallurgical analysis and beam simulation results.

  2. Compact electrostatic levitator for diffraction measurements with a two axis diffractometer and a laboratory x-ray source

    NASA Astrophysics Data System (ADS)

    Masaki, Tadahiko; Ishikawa, Takehiko; Paradis, Paul-François; Yoda, Shinichi; Okada, Junpei T.; Watanabe, Yasuhiro; Nanao, Susumu; Ishikura, Akiko; Higuchi, Kensuke; Mizuno, Akitoshi; Watanabe, Masato; Kohara, Shinji

    2007-02-01

    A compact electrostatic levitator was developed for the structural analysis of high-temperature liquids by x-ray diffraction methods. The size of the levitator was 200mm in diameter and 200mm in height and can be set up on a two axis diffractometer with a laboratory x-ray source, which is very convenient in performing structural measurements of high-temperature liquids. In particular, since the laboratory x-ray source allows a great amount of user time, preliminary or challenging experiments can be performed with trial and error, which prepares and complements synchrotron x-ray experiments. The present small apparatus also provides the advantage of portability and facility of setting. To demonstrate the capability of this electrostatic levitator, the static structure factors of alumina and silicon samples in their liquid phases were successfully measured.

  3. Selection of the appropriate radionuclide source for the efficiency calibration in methods of determining gross alpha activity in water.

    PubMed

    Corbacho, J A; Zapata-García, D; Montaña, M; Fons, J; Camacho, A; Guillén, J; Serrano, I; Baeza, A; Llauradó, M; Vallés, I

    2016-01-01

    Measuring the gross alpha activity in water samples is a rapid, straightforward way of determining whether the water might contain a radionuclide concentration whose consumption would imply a total indicative dose (TID) greater than some reference limit - currently set at 0.1 mSv/y in Europe. There are several methods used for such measurements. Two of them are desiccation with the salts being deposited on a planchet, and coprecipitation. The main advantage of these two methods is their ease of implementation and low cost of preparing the source to measure. However, there is considerable variability in the selection of the most suitable radioactive reference standard against which to calculate the water's gross alpha activity. The goal of this paper is to propose the most appropriate reference radionuclides to use as standards in determining gross alpha activities with these two methods, taking into account the natural radioactive characteristics of a wide range of waters collected at different points in Spain. Thus, the results will be consistent with each other and representative of the sum of alpha activities of all the alpha-emitters contained in a sample. PMID:26397746

  4. Psychophysical contrast calibration

    PubMed Central

    To, Long; Woods, Russell L; Goldstein, Robert B; Peli, Eli

    2013-01-01

    Electronic displays and computer systems offer numerous advantages for clinical vision testing. Laboratory and clinical measurements of various functions and in particular of (letter) contrast sensitivity require accurately calibrated display contrast. In the laboratory this is achieved using expensive light meters. We developed and evaluated a novel method that uses only psychophysical responses of a person with normal vision to calibrate the luminance contrast of displays for experimental and clinical applications. Our method combines psychophysical techniques (1) for detection (and thus elimination or reduction) of display saturating nonlinearities; (2) for luminance (gamma function) estimation and linearization without use of a photometer; and (3) to measure without a photometer the luminance ratios of the display’s three color channels that are used in a bit-stealing procedure to expand the luminance resolution of the display. Using a photometer we verified that the calibration achieved with this procedure is accurate for both LCD and CRT displays enabling testing of letter contrast sensitivity to 0.5%. Our visual calibration procedure enables clinical, internet and home implementation and calibration verification of electronic contrast testing. PMID:23643843

  5. Ultra-Stable Beacon Source for Laboratory Testing of Optical Tracking

    NASA Technical Reports Server (NTRS)

    Aso, Yoichi; Marka, Szabolcs; Kovalik, Joseph

    2008-01-01

    The ultra-stable beacon source (USBS) provides a laser-beam output with a very low angular jitter and can be used as an absolute angular reference to simulate a beacon in the laboratory. The laser is mounted on the top of a very short (approximately equal to 1 m) inverted pendulum (IP) with its optical axis parallel to the carbon fiber pendulum leg. The 85-cm, carbon fiber rods making up the leg are very lightweight and rigid, and are supported by a flex-joint at the bottom (see figure). The gimbal-mounted laser is a weight-adjustable load of about 1.5 kg with its center of rotation co-located with the center of percussion of the inverted pendulum. This reduces the coupling of transverse motion at the base of the pendulum to angular motion of the laser at the top. The inverted pendulum is mounted on a gimbal with its center of rotation coinciding with the pivot position of the inverted pendulum flexure joint. This reduces coupling of ground tilt at the inverted pendulum base to motion of the laser mounted at the top. The mass of the top gimbal is adjusted to give the pendulum a very low resonant frequency (approximately equal to 10 mHz) that filters transverse seismic disturbances from the ground where the base is attached. The motion of the IP is monitored by an optical-lever sensor. The laser light is reflected by the mirror on the IP, and then is detected by a quadrant photo-detector (QPD). The position of the beam spot on the QPD corresponds to the tilt of the IP. Damping of this motion is provided by two coil and magnet pairs. The bottom gimbal mount consists of two plates. The IP is mounted on the second plate. The first plate is supported by two posts through needles and can be rotated about the axis connecting the tips of the needles. The second plate hangs from the first plate and can be rotated about the axis perpendicular to the first plate. As a result, the second plate acts as a two-axis rotation stage. Its center of rotation is located at the

  6. A variable acceleration calibration system

    NASA Astrophysics Data System (ADS)

    Johnson, Thomas H.

    2011-12-01

    A variable acceleration calibration system that applies loads using gravitational and centripetal acceleration serves as an alternative, efficient and cost effective method for calibrating internal wind tunnel force balances. Two proof-of-concept variable acceleration calibration systems are designed, fabricated and tested. The NASA UT-36 force balance served as the test balance for the calibration experiments. The variable acceleration calibration systems are shown to be capable of performing three component calibration experiments with an approximate applied load error on the order of 1% of the full scale calibration loads. Sources of error are indentified using experimental design methods and a propagation of uncertainty analysis. Three types of uncertainty are indentified for the systems and are attributed to prediction error, calibration error and pure error. Angular velocity uncertainty is shown to be the largest indentified source of prediction error. The calibration uncertainties using a production variable acceleration based system are shown to be potentially equivalent to current methods. The production quality system can be realized using lighter materials and a more precise instrumentation. Further research is needed to account for balance deflection, forcing effects due to vibration, and large tare loads. A gyroscope measurement technique is shown to be capable of resolving the balance deflection angle calculation. Long term research objectives include a demonstration of a six degree of freedom calibration, and a large capacity balance calibration.

  7. SMAP RADAR Calibration and Validation

    NASA Astrophysics Data System (ADS)

    West, R. D.; Jaruwatanadilok, S.; Chaubel, M. J.; Spencer, M.; Chan, S. F.; Chen, C. W.; Fore, A.

    2015-12-01

    The Soil Moisture Active Passive (SMAP) mission launched on Jan 31, 2015. The mission employs L-band radar and radiometer measurements to estimate soil moisture with 4% volumetric accuracy at a resolution of 10 km, and freeze-thaw state at a resolution of 1-3 km. Immediately following launch, there was a three month instrument checkout period, followed by six months of level 1 (L1) calibration and validation. In this presentation, we will discuss the calibration and validation activities and results for the L1 radar data. Early SMAP radar data were used to check commanded timing parameters, and to work out issues in the low- and high-resolution radar processors. From April 3-13 the radar collected receive only mode data to conduct a survey of RFI sources. Analysis of the RFI environment led to a preferred operating frequency. The RFI survey data were also used to validate noise subtraction and scaling operations in the radar processors. Normal radar operations resumed on April 13. All radar data were examined closely for image quality and calibration issues which led to improvements in the radar data products for the beta release at the end of July. Radar data were used to determine and correct for small biases in the reported spacecraft attitude. Geo-location was validated against coastline positions and the known positions of corner reflectors. Residual errors at the time of the beta release are about 350 m. Intra-swath biases in the high-resolution backscatter images are reduced to less than 0.3 dB for all polarizations. Radiometric cross-calibration with Aquarius was performed using areas of the Amazon rain forest. Cross-calibration was also examined using ocean data from the low-resolution processor and comparing with the Aquarius wind model function. Using all a-priori calibration constants provided good results with co-polarized measurements matching to better than 1 dB, and cross-polarized measurements matching to about 1 dB in the beta release. During the

  8. Characterization of Wastewater Treatment Plant Microbial Communities and the Effects of Carbon Sources on Diversity in Laboratory Models

    PubMed Central

    Torok, Tamas; Wu, Cindy H.; Singer, Mary; Reid, Francine C.; Tarjan, Daniel R.; Hazen, Terry C.; Arkin, Adam P.; Hillson, Nathan J.

    2014-01-01

    We are developing a laboratory-scale model to improve our understanding and capacity to assess the biological risks of genetically engineered bacteria and their genetic elements in the natural environment. Our hypothetical scenario concerns an industrial bioreactor failure resulting in the introduction of genetically engineered bacteria to a downstream municipal wastewater treatment plant (MWWTP). As the first step towards developing a model for this scenario, we sampled microbial communities from the aeration basin of a MWWTP at three seasonal time points. Having established a baseline for community composition, we investigated how the community changed when propagated in the laboratory, including cell culture media conditions that could provide selective pressure in future studies. Specifically, using PhyloChip 16S-rRNA-gene targeting microarrays, we compared the compositions of sampled communities to those of inocula propagated in the laboratory in simulated wastewater conditionally amended with various carbon sources (glucose, chloroacetate, D-threonine) or the ionic liquid 1-ethyl-3-methylimidazolium chloride ([C2mim]Cl). Proteobacteria, Bacteroidetes, and Actinobacteria were predominant in both aeration basin and laboratory-cultured communities. Laboratory-cultured communities were enriched in γ-Proteobacteria. Enterobacteriaceae, and Aeromonadaceae were enriched by glucose, Pseudomonadaceae by chloroacetate and D-threonine, and Burkholderiacea by high (50 mM) concentrations of chloroacetate. Microbial communities cultured with chloroacetate and D-threonine were more similar to sampled field communities than those cultured with glucose or [C2mim]Cl. Although observed relative richness in operational taxonomic units (OTUs) was lower for laboratory cultures than for field communities, both flask and reactor systems supported phylogenetically diverse communities. These results importantly provide a foundation for laboratory models of industrial bioreactor

  9. Sources of Differences in On-Orbit Total Solar Irradiance Measurements and Description of Proposed Laboratory Intercomparison

    NASA Technical Reports Server (NTRS)

    Butler, J.J.; Johnson, B. C.; Rice, J. P.; Shirley, E. L.; Barnes, R.A.

    2008-01-01

    There is a 5 W/sq m (about 0.35 %) difference between current on-orbit Total Solar Irradiance (TSI) measurements. On 18-20 July 2005, a workshop was held at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland that focused on understanding possible reasons for this difference, through an examination of the instrument designs, calibration approaches, and appropriate measurement equations. The instruments studied in that workshop included the Active Cavity Radiometer Irradiance Monitor III (ACRIM III) on the Active Cavity Radiometer Irradiance Monitor SATellite (ACRIMSAT), the Total Irradiance Monitor (TIM) on the Solar Radiation and Climate Experiment (SORCE), the Variability of solar IRradiance and Gravity Oscillations (VIRGO) on the Solar and Heliospheric Observatory (SOHO), and the Earth Radiation Budget Experiment (ERBE) on the Earth Radiation Budget Satellite (ERBS). Presentations for each instrument included descriptions of its design, its measurement equation and uncertainty budget, and the methods used to assess on-orbit degradation. The workshop also included a session on satellite- and ground-based instrument comparisons and a session on laboratory-based comparisons and the application of new laboratory comparison techniques. The workshop has led to investigations of the effects of diffraction and of aperture area measurements on the differences between instruments. In addition, a laboratory-based instrument comparison is proposed that uses optical power measurements (with lasers that underEll the apertures of the TSI instruments), irradiance measurements (with lasers that overfill the apertures of the TSI instrument), and a cryogenic electrical substitution radiometer as a standard for comparing the instruments. A summary of the workshop and an overview of the proposed research efforts are presented here.

  10. Integration of Atmospheric, Laboratory, and Satellite Data to Estimate Biospheric Sources of Oxygenated Organic Compounds

    NASA Technical Reports Server (NTRS)

    Myneni, Ranga B.

    2001-01-01

    For this study, we intend to use a long time series of coarse resolution (8 km and quarter degree) vegetation leaf area index (LAI) and fraction of absorbed PAR (FAPAR) derived from AVHRR data for the time period July 1981 through Dec 2001. The Global Inventory Monitoring and Modeling Studies (GIMMS) data set of AVHRR channel reflectances currently was developed by Dr. Tucker at NASA Goddard. The spatial resolution of the data is 8 km, and a 15-day maximum Normalized Difference Vegetation Index (NDVI) composite time series for the period July 1981 through December 1999 has been produced. The data processing included improved navigation, calibration for intra- and inter-sensor variations, partial atmospheric correction for gaseous absorption and scattering. Stratospheric aerosol effects associated with volcanic eruptions were corrected using a combination of the methods for the data from the period April 1982 - December 1984 (El Chichon) and June 1991 - December 1993 (Mt. Pinatubo).

  11. Evaluation of stormwater micropollutant source control and end-of-pipe control strategies using an uncertainty-calibrated integrated dynamic simulation model.

    PubMed

    Vezzaro, L; Sharma, A K; Ledin, A; Mikkelsen, P S

    2015-03-15

    The estimation of micropollutant (MP) fluxes in stormwater systems is a fundamental prerequisite when preparing strategies to reduce stormwater MP discharges to natural waters. Dynamic integrated models can be important tools in this step, as they can be used to integrate the limited data provided by monitoring campaigns and to evaluate the performance of different strategies based on model simulation results. This study presents an example where six different control strategies, including both source-control and end-of-pipe treatment, were compared. The comparison focused on fluxes of heavy metals (copper, zinc) and organic compounds (fluoranthene). MP fluxes were estimated by using an integrated dynamic model, in combination with stormwater quality measurements. MP sources were identified by using GIS land usage data, runoff quality was simulated by using a conceptual accumulation/washoff model, and a stormwater retention pond was simulated by using a dynamic treatment model based on MP inherent properties. Uncertainty in the results was estimated with a pseudo-Bayesian method. Despite the great uncertainty in the MP fluxes estimated by the runoff quality model, it was possible to compare the six scenarios in terms of discharged MP fluxes, compliance with water quality criteria, and sediment accumulation. Source-control strategies obtained better results in terms of reduction of MP emissions, but all the simulated strategies failed in fulfilling the criteria based on emission limit values. The results presented in this study shows how the efficiency of MP pollution control strategies can be quantified by combining advanced modeling tools (integrated stormwater quality model, uncertainty calibration).

  12. Evaluation of stormwater micropollutant source control and end-of-pipe control strategies using an uncertainty-calibrated integrated dynamic simulation model.

    PubMed

    Vezzaro, L; Sharma, A K; Ledin, A; Mikkelsen, P S

    2015-03-15

    The estimation of micropollutant (MP) fluxes in stormwater systems is a fundamental prerequisite when preparing strategies to reduce stormwater MP discharges to natural waters. Dynamic integrated models can be important tools in this step, as they can be used to integrate the limited data provided by monitoring campaigns and to evaluate the performance of different strategies based on model simulation results. This study presents an example where six different control strategies, including both source-control and end-of-pipe treatment, were compared. The comparison focused on fluxes of heavy metals (copper, zinc) and organic compounds (fluoranthene). MP fluxes were estimated by using an integrated dynamic model, in combination with stormwater quality measurements. MP sources were identified by using GIS land usage data, runoff quality was simulated by using a conceptual accumulation/washoff model, and a stormwater retention pond was simulated by using a dynamic treatment model based on MP inherent properties. Uncertainty in the results was estimated with a pseudo-Bayesian method. Despite the great uncertainty in the MP fluxes estimated by the runoff quality model, it was possible to compare the six scenarios in terms of discharged MP fluxes, compliance with water quality criteria, and sediment accumulation. Source-control strategies obtained better results in terms of reduction of MP emissions, but all the simulated strategies failed in fulfilling the criteria based on emission limit values. The results presented in this study shows how the efficiency of MP pollution control strategies can be quantified by combining advanced modeling tools (integrated stormwater quality model, uncertainty calibration). PMID:25532057

  13. IYPT Problems as an Efficient Source of Ideas for First-Year Project Laboratory Tasks

    ERIC Educational Resources Information Center

    Planinsic, Gorazd

    2009-01-01

    In the project laboratory, a group of students are given a well-defined task but the path to the solution is entirely left to the students. The paper reports on some basic strategies in designing successful project tasks that are based on modified problems from International Young Physicists Tournament (IYPT). In addition, an integration of…

  14. Long Duration Multi-hohlraum X-ray Sources for Eagle Nebula Laboratory Experiments

    NASA Astrophysics Data System (ADS)

    Kane, Jave; Heeter, Robert; Martinez, David; Casner, Alexis; Villette, Bruno; Mancini, Roberto; Pound, Marc

    2013-10-01

    A novel foam-filled multi-hohlraum long-duration x-ray source has been demonstrated at the Omega EP laser and used to obtain L-band spectra of photoionized Ti. A larger scale version of the source will be used in the Science on NIF Eagle Nebula experiments studying dynamic evolution of distinctive pillar and cometary structures in star-forming clouds, where the long duration and directionality of photoionizing radiation from nearby stars generates new classes of flows and instabilities. At NIF, a target representing an astrophysical molecular cloud will be placed several mm from an x-ray source lasting 40-100 ns. At EP, three hohlraums were illuminated in sequence with 3.3 kJ pulses lasting 6 ns, or 4.3 kJ pulses lasting 10 ns, generating 18 or 30 ns of x-ray output at 90-100 eV color temperature. Performance of the source was validated using the μ DMX and VSG spectrometers, ASBO VISAR, and x-ray pinhole imagery. The HYDRA code suggests the EP-scale source can also be shot at NIF with at least 10 kJ per hohlraum. The multi-hohlraum source concept has potential further application to hard x-ray sources, soft x-ray backlighters, and nonlinear ablative hydrodynamics. Prepared by LLNL under Contract DE-AC52-07NA27344. J. Kane supported by DOE OFES grant HEDLP LAB 11-583.

  15. Investigating Sources of Toxicity in Stormwater: Algae Mortality in Runoff Upstream of the Lawrence Livermore National Laboratory

    SciTech Connect

    Campbell, C G; Folks, K; Mathews, S; Martinelli, R

    2003-10-06

    A source evaluation case study is presented for observations of algae toxicity in an intermittent stream passing through the Lawrence Livermore National Laboratory near Livermore, California. A five-step procedure is discussed to determine the cause of water toxicity problems and to determine appropriate environmental management practices. Using this approach, an upstream electrical transfer station was identified as the probable source of herbicides causing the toxicity. In addition, an analytical solution for solute transport in overland flow was used to estimate the application level of 40 Kg/ha. Finally, this source investigation demonstrates that pesticides can impact stream water quality regardless of application within levels suggested on manufacturer labels. Environmental managers need to ensure that pesticides that could harm aquatic organisms (including algae) not be used within close proximity to streams or storm drainages and that application timing should be considered for environmental protection.

  16. Self-Calibrating Pressure Transducer

    NASA Technical Reports Server (NTRS)

    Lueck, Dale E. (Inventor)

    2006-01-01

    A self-calibrating pressure transducer is disclosed. The device uses an embedded zirconia membrane which pumps a determined quantity of oxygen into the device. The associated pressure can be determined, and thus, the transducer pressure readings can be calibrated. The zirconia membrane obtains oxygen .from the surrounding environment when possible. Otherwise, an oxygen reservoir or other source is utilized. In another embodiment, a reversible fuel cell assembly is used to pump oxygen and hydrogen into the system. Since a known amount of gas is pumped across the cell, the pressure produced can be determined, and thus, the device can be calibrated. An isolation valve system is used to allow the device to be calibrated in situ. Calibration is optionally automated so that calibration can be continuously monitored. The device is preferably a fully integrated MEMS device. Since the device can be calibrated without removing it from the process, reductions in costs and down time are realized.

  17. Calibrating X-ray Imaging Devices for Accurate Intensity Measurement

    SciTech Connect

    Haugh, M. J.

    2011-07-28

    The purpose of the project presented is to develop methods to accurately calibrate X-ray imaging devices. The approach was to develop X-ray source systems suitable for this endeavor and to develop methods to calibrate solid state detectors to measure source intensity. NSTec X-ray sources used for the absolute calibration of cameras are described, as well as the method of calibrating the source by calibrating the detectors. The work resulted in calibration measurements for several types of X-ray cameras. X-ray camera calibration measured efficiency and efficiency variation over the CCD. Camera types calibrated include: CCD, CID, back thinned (back illuminated), front illuminated.

  18. Tracing water sources of terrestrial animal populations with stable isotopes: laboratory tests with crickets and spiders.

    PubMed

    McCluney, Kevin E; Sabo, John L

    2010-01-01

    Fluxes of carbon, nitrogen, and water between ecosystem components and organisms have great impacts across levels of biological organization. Although much progress has been made in tracing carbon and nitrogen, difficulty remains in tracing water sources from the ecosystem to animals and among animals (the "water web"). Naturally occurring, non-radioactive isotopes of hydrogen and oxygen in water provide a potential method for tracing water sources. However, using this approach for terrestrial animals is complicated by a change in water isotopes within the body due to differences in activity of heavy and light isotopes during cuticular and transpiratory water losses. Here we present a technique to use stable water isotopes to estimate the mean mix of water sources in a population by sampling a group of sympatric animals over time. Strong correlations between H and O isotopes in the body water of animals collected over time provide linear patterns of enrichment that can be used to predict a mean mix of water sources useful in standard mixing models to determine relative source contribution. Multiple temperature and humidity treatment levels do not greatly alter these relationships, thus having little effect on our ability to estimate this population-level mix of water sources. We show evidence for the validity of using multiple samples of animal body water, collected across time, to estimate the isotopic mix of water sources in a population and more accurately trace water sources. The ability to use isotopes to document patterns of animal water use should be a great asset to biologists globally, especially those studying drylands, droughts, streamside areas, irrigated landscapes, and the effects of climate change. PMID:21209877

  19. Tracing water sources of terrestrial animal populations with stable isotopes: laboratory tests with crickets and spiders.

    PubMed

    McCluney, Kevin E; Sabo, John L

    2010-12-31

    Fluxes of carbon, nitrogen, and water between ecosystem components and organisms have great impacts across levels of biological organization. Although much progress has been made in tracing carbon and nitrogen, difficulty remains in tracing water sources from the ecosystem to animals and among animals (the "water web"). Naturally occurring, non-radioactive isotopes of hydrogen and oxygen in water provide a potential method for tracing water sources. However, using this approach for terrestrial animals is complicated by a change in water isotopes within the body due to differences in activity of heavy and light isotopes during cuticular and transpiratory water losses. Here we present a technique to use stable water isotopes to estimate the mean mix of water sources in a population by sampling a group of sympatric animals over time. Strong correlations between H and O isotopes in the body water of animals collected over time provide linear patterns of enrichment that can be used to predict a mean mix of water sources useful in standard mixing models to determine relative source contribution. Multiple temperature and humidity treatment levels do not greatly alter these relationships, thus having little effect on our ability to estimate this population-level mix of water sources. We show evidence for the validity of using multiple samples of animal body water, collected across time, to estimate the isotopic mix of water sources in a population and more accurately trace water sources. The ability to use isotopes to document patterns of animal water use should be a great asset to biologists globally, especially those studying drylands, droughts, streamside areas, irrigated landscapes, and the effects of climate change.

  20. Anemometer calibrator

    NASA Technical Reports Server (NTRS)

    Bate, T.; Calkins, D. E.; Price, P.; Veikins, O.

    1971-01-01

    Calibrator generates accurate flow velocities over wide range of gas pressure, temperature, and composition. Both pressure and flow velocity can be maintained within 0.25 percent. Instrument is essentially closed loop hydraulic system containing positive displacement drive.