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Sample records for laboratory prepared thermoluminescent

  1. Method of preparing a thermoluminescent phosphor

    DOEpatents

    Lasky, Jerome B.; Moran, Paul R.

    1979-01-01

    A thermoluminescent phosphor comprising LiF doped with boron and magnesium is produced by diffusion of boron into a conventional LiF phosphor doped with magnesium. Where the boron dopant is made to penetrate only the outer layer of the phosphor, it can be used to detect shallowly penetrating radiation such as tritium beta ays in the presence of a background of more penetrating radiation.

  2. Preparation methods of thermoluminescent materials for dosimetric applications: an overview.

    PubMed

    Azorin, Juan

    2014-01-01

    Many different natural minerals and synthetic inorganic compounds present the phenomenon of thermoluminescence (TL); however, only a part of them satisfy the requirements to be used as TL dosimeters. The mechanism of excitation energy transformation into the output of light is one of the most important points in the TL materials designing. Both the threshold detection dose and accuracy of measurements depend on the efficiency of energy transformation. The role of diverse mechanisms of energy transfer and energy losses is very different depending on the nature of the TL material and its composition including intrinsic defects and those induced by impurities. The structure of these defects can be controlled to a high extent by the preparation method. That is why the most important fact is to find the interrelations among the preparation methods, the structural defects and the TL properties of the material. The aim of this paper is to give a selected review on the preparation methods of the most popular and commercially available phosphors as well as those less used or "homemade" for special studies.

  3. Preparation, thermoluminescence, photoluminescence and dosimetric characteristics of LiF:Mg,Cu,P,B phosphor

    NASA Astrophysics Data System (ADS)

    Preto, Prince D.; Vidyavathy, B.; Dhabekar, Bhushan S.

    2017-01-01

    This paper presents the preparation, thermoluminescence, thermoluminescence (TL) emission, photoluminescence (PL) emission and dosimetric properties of a new LiF:Mg,Cu,P,B (MCPB) phosphor. This phosphor shows an enhanced sensitivity and is 27 times more sensitive than LiF:Mg,Ti and 1.15 times more sensitive than LiF:Mg,Cu,P (MCP). The position and shape of the glow curve of MCPB is very much similar to that of MCP, but the intensity of the main dosimetric peak increases, reaches a maximum at a concentration of about 0.025 mol% and then decreases slowly upon further addition of boron. The main dosimetric peak of the phosphor appears at 220 °C and is linear up to 10 Gy with a minimum detectable dose of about 10 μGy. MCPB phosphor can be reused up to 10 cycles at an annealing temperature of 260 °C for 10 min without loss in TL sensitivity. MCPB exhibits a very low residual signal (0.42 %) when compared to that of GR-200A and GR-200P reported in the literature. The structural and morphological characteristics of the phosphor have been studied using X-ray diffraction method and scanning electron microscope. Both the TL and PL emission spectrum are recorded and analyzed. The various other dosimetric properties like annealing temperature, fading, reusability and residual signal are also presented in this study.

  4. Polymer Preparations in the Laboratory.

    ERIC Educational Resources Information Center

    Lampman, Gary M.; And Others

    1979-01-01

    Describes six laboratory procedures for preparing polymers which have been used in a course for undergraduate industrial arts students, who have a concentration in plastics technology but have not taken more than one year of college chemistry. (BT)

  5. Thermoluminescence analysis of aerosols

    NASA Technical Reports Server (NTRS)

    Long, E. R., Jr.; Rogowski, R. S.

    1979-01-01

    Method is presented for identifying air pollutants in field or laboratory by technique based on thermoluminescence. Approach is useful in tracing dispersion of pollutants over geographical regions and in determining cancer causing agents in the upper atmosphere.

  6. Topics in Chemical Instrumentation, Cl. Thermoluminescence: Part II. Instrumentation.

    ERIC Educational Resources Information Center

    Manche, Emanuel P.

    1979-01-01

    Presents part two on the use of the detection of thermoluminescence as an analytical tool for the chemistry laboratory and allied science. This part discusses instrumentation used and investigates recent developments in instrumentation for thermoluminescence. (HM)

  7. Elucidation of the annealing process required in the preparation of the thermoluminescence phosphor of CaSO4:Tm

    NASA Astrophysics Data System (ADS)

    Shinsho, Kiyomitsu; Watanabe, Eiji; Urushiyama, Akio

    2006-11-01

    The thermoluminescence phosphor of CaSO4:Tm was subjected to physicochemical studies. Careful thermo mass spectrometry and thermogravimetry/differential thermal analysis studies for a solid sample prepared by 200°C evaporation of a sulfuric acid medium without annealing by an extremely slow speed of temperature elevation were carried out. The data revealed, along with an initial weight loss corresponding to a small, nonstoichiometric amount of crystal water at 200°C, evidence for reaction with H2O vapor in air between 300 and 500°C and a 550°C and a subsequent release of SOx at higher temperatures until the beginning of bursting decomposition of CaSO4 bulk above 700°C. H1 NMR study revealed a broad signal at 9.9ppm, which was easily assigned to the crystal water involved. This initial solid has no thermostimulated luminescence (TL) efficiency. The first signal at 9.9ppm disappeared at 200°C. A new signal appeared at 13.1ppm by annealing from 300°C and increased significantly in intensity during annealing up to 600°C, which could be assigned to the intermediate produced by the reaction with H2O vapor in air. The intensity of this signal in turn was reduced by annealing at temperatures higher than 600°C and almost disappeared at 800°C. The solid by annealing at 700°C has the best TL efficiency. Several lines of the present physicochemical evidence suggest that the energy trap on irradiation of ionizing radiation is related to the concentration of O2- produced by the decomposition of SO42- during the annealing process in the course of the preparation of CaSO4:RE.

  8. Laboratory Preparation in the Ocular Therapy Curriculum.

    ERIC Educational Resources Information Center

    Cummings, Roger W.

    1986-01-01

    Aspects of laboratory preparation necessary for undergraduate or graduate optometric training in the use of therapeutic drugs are discussed, including glaucoma therapy, anterior segment techniques, posterior segment, and systemic procedures. (MSE)

  9. Thermoluminescence dosimeter

    DOEpatents

    Zendle, Robert

    1985-01-01

    A thermoluminescence dosimeter having a very small rate of decline of sensitivity during subsequent uses after heating is disclosed. The dosimeter includes a detector crystal and a glass enclosure in which the detector crystal is located. The glass enclosure is air tight and is filled with a super dry inert fill gas. The inert fill gas is nonreactive with the detector crystal when the detector crystal is heated to thermoluminescence. The fill gas is selected from the group consisting of air, nitrogen, and argon, suitable admixed with 5 to 25 percent helium. The detector crystal consists essentially of calcium fluoride. The fill gas is preferably contained at a subatmospheric pressure in the glass enclosure.

  10. Thermoluminescence dosimeter

    DOEpatents

    Zendle, R.

    1983-11-03

    A thermoluminescence dosimeter having a very small rate of decline of sensitivity during subsequent uses after heating is disclosed. The dosimeter includes a detector crystal and a glass enclosure in which the detector crystal is located. The glass enclosure is air tight and is filled with a super dry inert fill gas. The inert fill gas is nonreactive with the detector crystal when the detector crystal is heated to thermoluminescence. The fill gas is selected from the group consisting of air, nitrogen, and argon, suitable admixed with 5 to 25 percent helium. The detector crystal consists essentially of calcium fluoride. The fill gas is preferably contained at a subatmospheric pressure in the glass enclosure.

  11. Thermoluminescent phosphor

    DOEpatents

    Lasky, Jerome B.; Moran, Paul R.

    1978-01-01

    A thermoluminescent phosphor comprising LiF doped with boron and magnesium is produced by diffusion of boron into a conventional LiF phosphor doped with magnesium. Where the boron dopant is made to penetrate only the outer layer of the phosphor, it can be used to detect shallowly penetrating radiation such as tritium beta rays in the presence of a background of more penetrating radiation.

  12. Thermoluminescent dosimetry for LDEF experiment M0006

    NASA Technical Reports Server (NTRS)

    Chang, J. Y.; Giangano, D.; Kantorcik, T.; Stauber, M.; Snead, L.

    1992-01-01

    Experiment M0006 on the Long Duration Exposure Facility had as its objective the investigation of space radiation effects on various electronic and optical components, as well as on seed germination. The Grumman Corporate Research Center provided the radiation dosimetric measurements for M0006, comprising the preparation of thermoluminescent dosimeters (TLD) and the subsequent measurement and analysis of flight exposed and control samples. In addition, various laboratory exposures of TLD's with gamma rays and protons were performed to obtain a better understanding of the flight exposures.

  13. Bone preparation at the KCCAMS laboratory

    NASA Astrophysics Data System (ADS)

    Beaumont, Will; Beverly, Robert; Southon, John; Taylor, R. E.

    2010-04-01

    Collagen purification by ultrafiltration [1] is becoming widely accepted as a superior 14C sample preparation method for removing environmental contamination from archaeological bone. We present an overview of bone sample preparation methods used at the KCCAMS laboratory, UC Irvine. Methods development data are also discussed, including results of tests of gelatinization temperature, evaluation of 10 kDa vs. 30 kDa molecular weight (MW) ultrafiltration, improvements to ultrafilter cleaning methods, tests of ultrafilter memory, and ultrafilter glycerin contamination. These tests were not intended to be exhaustive, but rather to show how standard procedures can be validated and improved with relatively little effort.

  14. Los Alamos National Laboratory Prepares for Fire Season

    SciTech Connect

    L’Esperance, Manny

    2016-07-18

    Through the establishment of a Wildland Fire Program Office, and the Interagency Fire Base located on Laboratory property, Los Alamos National Laboratory is continuing and improving a program to prepare for wildland fire.

  15. Los Alamos National Laboratory Prepares for Fire Season

    ScienceCinema

    L’Esperance, Manny

    2016-08-10

    Through the establishment of a Wildland Fire Program Office, and the Interagency Fire Base located on Laboratory property, Los Alamos National Laboratory is continuing and improving a program to prepare for wildland fire.

  16. Preparation of Unconsolidated Sands for Microscopy Laboratory Exercises.

    ERIC Educational Resources Information Center

    Cameron, Barry; Jones, J. Richard

    1988-01-01

    Describes a technique of impregnating small amounts of sandy sediment in a quick curing resin for microscopic examination. Details the preparation of materials. Suggests laboratory exercises based on this preparation. (CW)

  17. Thermoluminescence, ESR and x-ray diffraction studies of CaSO4 : Dy phosphor subjected to post preparation high temperature thermal treatment

    NASA Astrophysics Data System (ADS)

    Bakshi, A. K.; Patwe, S. J.; Bhide, M. K.; Sanyal, B.; Natarajan, V.; Tyagi, A. K.; Kher, R. K.

    2008-01-01

    Thermoluminescence (TL), electron spin resonance (ESR) and x ray diffraction studies of CaSO4 : Dy phosphor subjected to post preparation high temperature treatment were carried out. Analysis of the TL glow curve indicated that the dosimetric glow peak at 240 °C reduces, whereas the low temperature satellite peak increases with the increase in the annealing temperature in the range 650-1000 °C. The influence of the annealing atmosphere on the TL glow curve structure was also observed. Reduction of the photoluminescence intensity of the annealed phosphor indicated that the environment of Dy3+ ions might have undergone some change due to high temperature treatment. Reduction in the ESR signal intensity corresponding to O_{3}^{-} and SO_{3}^{-} radicals was observed initially with the increase in the annealing temperaure; subsequently their intensity increased with temperature. Signals due to the SO_{4}^{-} radical vanished, when the phosphor was annealed beyond 800 °C. A signal corresponding to SH2- radicals was also observed in the ESR spectra for samples subjected to annealing in the temperature regime 800-1000 °C. XRD of the in situ annealed phosphor showed a change in the unit cell parameters. An endothermic peak at 860 °C in the DTA spectrum was observed.

  18. Possible Thermoluminescence of the Solid Cometary Substance: Thermoluminescence of Commentary Substance

    NASA Astrophysics Data System (ADS)

    Simonia, Irakli

    2016-10-01

    The article describes a mechanism of the possible thermoluminescence of solid cometary substances, including dusty halos. We propose to consider comet flares as the thermoluminescence of the cometary ices and mineral dust. The article provides the results of some laboratory experiments on frozen phosphorescence of a number of minerals (quartz, forsterite, and diamond) conducted over the past several years and relevant for reviewing the given problem. We also propose a concept of the comet’s luminescent relictography and some scientific initiations. Properties of red and blue thermoluminescence flares of cometary halos are described, and we consider the similarity of thermoluminescence and cathodoluminescence processes of cometary dust. Various aspects of the problem are under discussion.

  19. Thermoluminescence of lunar samples

    USGS Publications Warehouse

    Dalrymple, G.B.; Doell, Richard R.

    1970-01-01

    Appreciable natural thermoluminescence with glow curve peaks at about 350 degrees centigrade for lunar fines and breccias and above 400 degrees centigrade for crystalline rocks has been recognized in lunar samples. Plagioclase has been identified as the principal carrier of thermoluminescence, and the difference in peak temperatures indicates compositional or structural differences between the feldspars of the different rock types. The present thermoluminescence in the lunar samples is probably the result of a dynamic equilibrium between acquisition from radiation and loss in the lunar thermal environment. A progressive change in the glow curves of core samples with depth below the surface suggests the use of thermoluminescence disequilibrium to detect surfaces buried by recent surface activity, and it also indicates that the lunar diurnal temperature variation penetrates to at least 10.5 centimeters.

  20. Thermoluminescence: Potential Applications in Forensic Science

    NASA Technical Reports Server (NTRS)

    Ingham, J. D.; Lawson, D. D.

    1973-01-01

    In crime laboratories one of the most difficult operations is to determine unequivocally whether or not two samples of evidence of the same type were originally part of the same thing or were from the same source. It has been found that high temperature thermoluminescence (room temperature to 723 K) can be used for comparisons of this type, although work to date indicates that there is generally a finite probability for coincidental matching of glass or soil samples. Further work is required to determine and attempt to minimize these probabilities for different types of materials, and to define more clearly the scope of applicability of thermoluminescence to actual forensic situations.

  1. Analysis of thermoluminescence of Li2B4O7:Cu, Ag, P phosphor by simplified General one Trap differential equation

    NASA Astrophysics Data System (ADS)

    Singh, A. N.; Singh, S. N.; Singh, L. L.

    2015-01-01

    Lithium tetraborate based phosphor (Li2B4O7:Cu, Ag, P) is a suitable material for thermoluminescence dosimetery. It is prepared at Thermoluminescence Dosimetry Laboratory, Thoubal College, Manipur and has been analyzed using recently formulated simplified General one Trap equation to determine the trapping parameters. This new simplified equation helps in finding the key trapping parameters E, s, N, γ and α, which is not possible with the well known kinetic order formalism. From the analysis, it is found that activation energy of the phosphor is in the range 0.80-1.14 eV and frequency factor is 108-1010 s-1.

  2. Thermoluminescence emission spectrometer.

    PubMed

    Prescott, J R; Fox, P J; Akber, R A; Jensen, H E

    1988-08-15

    A sensitive thermoluminescence (TL) emission spectrometer based on Fourier transform spectroscopy is described. It employs a modified scanning Twyman-Green interferometer with photomultiplier detection in a photon-counting mode. The etendue is 180pi mm(2), and it covers the 350-600-nm wavelength range. The output can be displayed either as a 3-D isometric plot of intensity vs temperature and wavelength, as a contour diagram, or as a conventional TL glow curve of intensity vs temperature. It is sufficiently sensitive to record thermoluminescence spectra of dosimeter phosphors and minerals for thermoluminescence dating at levels corresponding to those found during actual use as radiation monitors or in dating. Examples of actual spectra are given.

  3. Environmental radiation detection via thermoluminescence

    DOEpatents

    Miller, Steven D.

    1993-01-01

    The method and apparatus of the present invention relate to cryogenically cooling a thermoluminescent material, exposing it to a low level of radiation (less than about 1 R) while it is at the cooled temperature, warming the thermoluminescent material to "room temperature", and counting the photons emitted during heating. Sufficient sensitivity is achieved without exposing the thermoluminescent material to ultraviolet light thereby simplifying the measurements.

  4. Environmental radiation detection via thermoluminescence

    DOEpatents

    Miller, S.D.

    1993-03-23

    The method and apparatus of the present invention relate to cryogenically cooling a thermoluminescent material, exposing it to a low level of radiation (less than about 1 R) while it is at the cooled temperature, warming the thermoluminescent material to room temperature'' and counting the photons emitted during heating. Sufficient sensitivity is achieved without exposing the thermoluminescent material to ultraviolet light thereby simplifying the measurements.

  5. Thermoluminescence properties of ZnO and ZnO:Yb nanophosphors

    NASA Astrophysics Data System (ADS)

    Pal, U.; Meléndrez, R.; Chernov, V.; Barboza-Flores, M.

    2006-10-01

    ZnO and ZnO:Yb thermoluminescence nanophosphors have been developed and tested under beta radiation. Spherical nanoparticles of sizes ranging from 130to1200nm were prepared through a glycol mediated chemical synthesis. The Yb doping had a thermoluminescence quenching effect compared to undoped ZnO. The 5% Yb concentration produced a low fading, a single thermoluminescence glow peak structure, and a dose linearity behavior adequate for thermoluminescence dosimetry applications. The ZnO:Yb nanophosphor has a great potential as a dosimeter for monitoring in ionizing radiation fields.

  6. Thermoluminescence properties of ZnO and ZnO:Yb nanophosphors

    SciTech Connect

    Pal, U.; Melendrez, R.; Chernov, V.; Barboza-Flores, M.

    2006-10-30

    ZnO and ZnO:Yb thermoluminescence nanophosphors have been developed and tested under beta radiation. Spherical nanoparticles of sizes ranging from 130 to 1200 nm were prepared through a glycol mediated chemical synthesis. The Yb doping had a thermoluminescence quenching effect compared to undoped ZnO. The 5% Yb concentration produced a low fading, a single thermoluminescence glow peak structure, and a dose linearity behavior adequate for thermoluminescence dosimetry applications. The ZnO:Yb nanophosphor has a great potential as a dosimeter for monitoring in ionizing radiation fields.

  7. Testing hygrometers used in cytogenetics laboratories for metaphase preparation.

    PubMed

    Hartley, Thomas; Dun, Karen

    2011-07-01

    This protocol describes procedures for checking small laboratory hygrometers for accuracy at three relative humidity (rh) levels. The work arose out of the need to provide laboratory assessors with documentary evidence that the hygrometer used to monitor humidity in the vicinity of the laboratory where medical cytogenetics testing slides are prepared and dried in the ambient environment is reproducible and sufficiently accurate. The procedure is based upon the physicochemical principle that when water or certain saturated salt solutions are placed into a sealed environment, the humidity will equilibrate to well defined levels. We choose to check our hygrometers at three points: 95%, 75%, and 33% rh, using distilled water, saturated sodium chloride solution, and saturated magnesium chloride solution, respectively. Our results have demonstrated that the procedure is convenient and of sufficient accuracy to be fit for this annual hygrometer validation purpose. The procedure takes 24 hr per relative humidity point checked.

  8. Designing Online Resources in Preparation for Authentic Laboratory Experiences

    PubMed Central

    Boulay, Rachel; Parisky, Alex; Leong, Peter

    2013-01-01

    Professional development for science teachers can be benefited through active learning in science laboratories. However, how online training materials can be used to complement traditional laboratory training is less understood. This paper explores the design of online training modules to teach molecular biology and user perception of those modules that were part of an intensive molecular biology “boot camp” targeting high school biology teachers in the State of Hawaii. The John A. Burns School of Medicine at the University of Hawaii had an opportunity to design and develop professional development that prepares science teachers with an introduction of skills, techniques, and applications for their students to conduct medical research in a laboratory setting. A group of 29 experienced teachers shared their opinions of the online materials and reported on how they used the online materials in their learning process or teaching. PMID:24319698

  9. Thermoluminescence as a palaeothermometer

    NASA Technical Reports Server (NTRS)

    Guimon, R. K.; Weeks, K. S.; Keck, B. D.; Sears, D. W. G.

    1984-01-01

    The results of annealing experiments on a little-metamorphosed (type 3.5) ordinary chondrite are reported. The thermoluminescence (TL) emission characteristics of the annealed samples show trends very similar to those observed in meteorites which have been naturally metamorphosed in various degrees. The trends are also similar to those observed in annealing experiments on terrestrial albite, where the changes are associated with the low-to-high temperature transformation. These results suggest that the TL phosphor in meteorites is feldspar and that TL can be used to estimate paleotemperatures for little-metamorphosed and highly unequilibrated meteorites.

  10. Preparing clinical laboratory science students with teaching skills.

    PubMed

    Isabel, Jeanne M

    2010-01-01

    Training clinical laboratory science (CLS) students in techniques of preparation and delivery of an instructional unit is an important component of all CLS education programs and required by the national accrediting agency. Participants of this study included students admitted to the CLS program at Northern Illinois University and enrolled in the teaching course offered once a year between the years of 1997 and 2009. Courses on the topic of "teaching" may be regarded by CLS students as unnecessary. However, entry level practitioners are being recruited to serve as clinical instructors soon after entering the workforce. Evaluation of the data collected indicates that students are better prepared to complete tasks related to instruction of a topic after having an opportunity to study and practice skills of teaching. Mentoring CLS students toward the career role of clinical instructor or professor is important to maintaining the workforce.

  11. Alumina as a Thermoluminescent Material

    SciTech Connect

    Uzun, Erdem; Yarar, Yasemin

    2007-04-23

    Thermoluminescence dosimeters are extensively used for quantitative dose measurements in various irradiation fields. They are also important for environmental monitoring after nuclear accident and weapon tests. In this work, the principles of TLD dosimeter and characteristics of several TLD materials are presented. Besides, taken into account the importance as a raw material, the utilization of domestic alumina (Al2O3) in TLDs as a thermoluminescent material is discussed.

  12. Thermoluminescent (TL) trap characteristics in irradiated oregano herb

    NASA Astrophysics Data System (ADS)

    Furetta, C.; Cruz-Zaragoza, E.

    The aim of this article is to investigate in a very simple way the trap characteristics of the irradiated oregano herb. The preparation of the polymineral dust obtained from the herb is described and then, through a fading experiment, the characteristics of the trapping levels responsible of the thermoluminescent emission are discussed.

  13. Iodine Standard Materials: Preparation and Inter-Laboratory Comparisons

    SciTech Connect

    D D Jenson; M L Adamic; J E Olson; M G Watrous; C Vockenhuber

    2014-08-01

    The Idaho National Laboratory is preparing to enter the community of AMS practioners who analyze for 129Iodine. We expect to take delivery of a 0.5 MV compact accelerator mass spectrometry system, built by NEC, in the early summer of 2014. The primary mission for this instrument is iodine; it is designed to analyze iodine in the +3 charge state. As part of the acceptance testing for this instrument, both at NEC and on-site in our laboratory, some sort of standard or reference material is needed to verify performance. Appropriate standard materials are not readily available in the commercial marketplace. Small quantities can sometimes be acquired from other laboratories already engaged in iodine analyses. In the longer-term, meaningful quantities of standard materials are needed for routine use in analyses, and for quality control functions1. We have prepared some standard materials, starting with elemental Woodward iodine and NIST SRM 3231 [Iodine-129 Isotopic Standard (high level)] 10-6 solution. The goal was to make mixtures at the 5x10-10, 5x10-11, 5x10-12 ratio levels, along with some unmodified Woodward, in the chemical form of silver iodide. Approximately twenty grams of each of these mixtures were prepared. The elemental Woodward iodine was dissolved in chloroform, then reduced to iodide using sodium bisulfite in water. At this point the NIST spike material was added, in the form of sodium iodide. The mixed iodides were oxidized back to iodine in chloroform using hydrogen peroxide. This oxidation step was essential for isotopic equilibration of the 127 and 129 atoms. The iodine was reduced to iodide using sodium bisulfite as before. Excess sulfites and sulfates were precipitated with barium nitrate. After decanting, silver nitrate was used to precipitate the desired silver iodide. Once the silver iodide was produced, the material was kept in darkness as much as possible to minimize photo-oxidation. The various mixtures were synthesized independently of each

  14. Oak Ridge National Laboratory's Preparations for Additional Protocol Implementation

    SciTech Connect

    McCowan, Janie; Cain, Ronald A

    2009-01-01

    The United States Additional Protocol (AP) with the International Atomic Energy Agency (IAEA) entered into force (EIF) January 6, 2009. In anticipation of the EIF, the Department of Energy (DOE) National Nuclear Security Administration Office of International Regimes and Agreements (NA-243) began the initial DOE AP data call on November 3, 2008. This paper describes the Oak Ridge National Laboratory's (ORNL's) preparation, organization, and development efforts to successfully implement the AP and complete the AP data call. ORNL had 35 days to identify declarable activities and finalize the declaration line items (DLIs) for submission to NA-243. To be able to respond within the required time frame, many preparation activities at ORNL were necessary, such as determining the AP coordinator (APC) and team roles; conducting site awareness training; creating the ORNL Standards-Based Management System (SBMS) procedure Reporting of Nuclear Fuel Cycle Activities; training personnel; and defining site implementation software tools. Identifying, updating, compiling, reviewing, and submitting the DLIs to NA-243 were all critical activities for successfully implementing the AP and completing the AP data call at ORNL.

  15. Thermoluminescence and Antarctic meteorites

    NASA Technical Reports Server (NTRS)

    Sears, D. W. G.; Hasan, F. A.

    1986-01-01

    The level of natural thermoluminescence (TL) in meteorites is the result of competition between build-up, due to exposure to cosmic radiation, and thermal decay. Antarctic meteorites tend to have lower natural TL than non-Antarctic meteorites because of their generally larger terrestrial ages. However, since a few observed falls have low TL due to a recent heating event, such as passage within approximately 0.7 astronomical units of the Sun, this could also be the case for some Antarctic meteorites. Dose rate variations due to shielding, heating during atmospheric passage, and anomalous fading also cause natural TL variations, but the effects are either relatively small, occur infrequently, or can be experimentally circumvented. The TL sensitivity of meteorites reflects the abundance and nature of the feldspar. Thus intense shock, which destroys feldspar, causes the TL sensitivity to decrease by 1 to 2 orders of magnitude, while metamorphism, which generates feldspar through the devitrification of glass, causes TL sensitivity to increase by a factor of approximately 10000. The TL-metamorphism relationship is particularly strong for the lowest levels of metamorphism. The order-disorder transformation in feldspar also affect the TL emission characteristics and thus TL provides a means of paleothermometry.

  16. PHYSICAL PROPERTY MEASUREMENTS OF LABORATORY PREPARED SALTSTONE GROUT

    SciTech Connect

    Hansen, E.; Cozzi, A.; Edwards, T.

    2014-05-05

    The Saltstone Production Facility (SPF) built two new Saltstone Disposal Units (SDU), SDU 3 and SDU 5, in 2013. The variable frequency drive (VFD) for the grout transfer hose pump tripped due to high current demand by the motor during the initial radioactive saltstone transfer to SDU 5B on 12/5/2013. This was not observed during clean cap processing on July 5, 2013 to SDU 3A, which is a slightly longer distance from the SPF than is SDU 5B. Saltstone Design Authority (SDA) is evaluating the grout pump performance and capabilities to transfer the grout processed in SPF to SDU 3/5. To assist in this evaluation, grout physical properties are required. At this time, there are no rheological data from the actual SPF so the properties of laboratory prepared samples using simulated salt solution or Tank 50 salt solution will be measured. The physical properties of grout prepared in the laboratory with de-ionized water (DI) and salt solutions were obtained at 0.60 and 0.59 water to premix (W/P) ratios, respectively. The yield stress of the DI grout was greater than any salt grout. The plastic viscosity of the DI grout was lower than all of the salt grouts (including salt grout with admixture). When these physical data were used to determine the pressure drop and fluid horsepower for steady state conditions, the salt grouts without admixture addition required a higher pressure drop and higher fluid horsepower to transport. When 0.00076 g Daratard 17/g premix was added, both the pressure drop and fluid horsepower were below that of the DI grout. Higher concentrations of Daratard 17 further reduced the pressure drop and fluid horsepower. The uncertainty in the single point Bingham Plastic parameters is + 4% of the reported values and is the bounding uncertainty. Two different mechanical agitator mixing protocols were followed for the simulant salt grout, one having a total mixing time of three minutes and the other having a time of 10 minutes. The Bingham Plastic parameters

  17. Air Force Research Laboratory Preparation for Year 2000.

    DTIC Science & Technology

    2007-11-02

    Air Force Research Laboratory , Phillips Research Site , Kirkland Air Force Base, New...Pentagon, Washington, D.C. 20301-1900. The identity of each writer and caller is fully protected. Acronym AFRL Air Force Research Laboratory INSPECTOR...completion of the implementation phase was May 31, 1999. Air Force Research Laboratory . The Air Force Research

  18. Method for detecting radiation dose utilizing thermoluminescent material

    DOEpatents

    Miller, Steven D.; McDonald, Joseph C.; Eichner, Fred N.; Durham, James S.

    1992-01-01

    The amount of ionizing radiation to which a thermoluminescent material has been exposed is determined by first cooling the thermoluminescent material and then optically stimulating the thermoluminescent material by exposure to light. Visible light emitted by the thermoluminescent material as it is allowed to warm up to room temperature is detected and counted. The thermoluminescent material may be annealed by exposure to ultraviolet light.

  19. An Alternative Approach for Preparing and Standardizing Some Common Aqueous Reagents Used in an Undergraduate Laboratory

    ERIC Educational Resources Information Center

    Melaku, Samuel; Dabke, Rajeev B.

    2014-01-01

    A guide for instructors and laboratory assistants to prepare some common aqueous reagents used in an undergraduate laboratory is presented. Dilute reagents consisting of H[superscript +](aq), I[subscript 3][superscript-](aq), Ce[superscript 4+](aq), and Ag[superscript+](aq) were prepared by electrolytic oxidation of respective precursors.…

  20. STRUCTURED LEARNING AND TRAINING ENVIRONMENTS--A PREPARATION LABORATORY FOR ADVANCED MAMMALIAN PHYSIOLOGY.

    ERIC Educational Resources Information Center

    FIEL, NICHOLAS J.; JOHNSTON, RAYMOND F.

    A PREPARATION LABORATORY WAS DESIGNED TO FAMILIARIZE STUDENTS IN ADVANCED MAMMALIAN PHYSIOLOGY WITH LABORATORY SKILLS AND TECHNIQUES AND THUS SHORTEN THE TIME THEY SPEND IN SETTING UP ACTUAL EXPERIMENTS. THE LABORATORY LASTS 30 MINUTES, IS FLEXIBLE AND SIMPLE OF OPERATION, AND DOES NOT REQUIRE A PROFESSOR'S PRESENCE. THE BASIC TRAINING UNIT IS THE…

  1. Thermoluminescence characteristics of hydrogenated amorphous zirconia

    NASA Astrophysics Data System (ADS)

    Montalvo, T. R.; Tenorio, L. O.; Nieto, J. A.; Salgado, M. B.; Estrada, A. M. S.; Furetta, C.

    2005-05-01

    This paper reports the experimental results concerning the thermoluminescent (TL) characteristics of hydrogenated amorphous zirconium oxide (a-Zr:H) powder prepared by the sol-gel method. The advantages of this method are the homogeneity and the purity of the gels associated with a relatively low sintering temperature. Hydrogenated amorphous powder was characterized by thermal analysis and X-ray diffraction. The main TL characteristics investigated were the TL response as a function of the absorbed dose, the reproducibility of the TL readings and the fading. The undoped a-Zr:H powder presents a TL glow curve with two peaks centered at 150 and 260 degrees C, respectively, after beta irradiation. The TL response a-Zr:H as a function of the absorbed dose showed a linear behavior over a wide range. The results presented open the possibility to use this material as a good TL dosimeter.

  2. Method and apparatus for reading thermoluminescent phosphors

    DOEpatents

    Braunlich, Peter F.; Tetzlaff, Wolfgang

    1987-01-01

    An apparatus and method for rapidly reading thermoluminescent phosphors to determine the amount of luminescent energy stored therein. The stored luminescent energy is interpreted as a measure of the total exposure of the thermoluminescent phosphor to ionizing radiation. The thermoluminescent phosphor reading apparatus uses a laser to generate a laser beam. The laser beam power level is monitored by a laser power detector and controlled to maintain the power level nearly constant. A shutter or other laser beam interrupting means is used to control exposure of the thermoluminescent phosphor to the laser beam. The laser beam can be equalized using an optical equalizer so that the laser beam has an approximately uniform power density across the beam. The heated thermoluminescent phosphor emits a visible or otherwise detectable luminescent emission which is measured as an indication of the radiation exposure of the thermoluminescent phosphors. Also disclosed are preferred signal processing and control circuits.

  3. The Principles of Phototransferred Thermoluminescence

    SciTech Connect

    Moscovitch, Marko

    2011-05-05

    The principles of phototransferred thermoluminescence (PTTL) are described, and some of the basic theoretical ideas underlying this technique are presented. It is demonstrated that the PTTL efficiency is dependent on the photon energy as well as on the activation energies of the various traps involved in the process. A simple two-traps-one-recombination-center model is capable of predicting a variety of different PTTL behaviors, some already were observed experimentally.

  4. Molybdenum-99 Isotope Production Preparation at Sandia National Laboratories

    SciTech Connect

    Carson, S.D.; Longley, S.W.; McDonald, M.J.; Parma, E.J.; Vernon, M.E.

    1998-10-07

    `Q&c M. J. McDonald, S. D. Carson, S. W. Longley, E. J. Parma, M. E. Vern `~ I@ .,., Sandia National Laboratories*, P. .0. Box 5800, Albuquerque, NM, 8 W? 1$ tl?;:q `f. (3 . 8 /'~ Abstract This report was prepared as an account of work sponsored byanagency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. loading on the Cintichem targets. These tests were designed to gain process knowledge prior to processing an irradiated target. The chemical separation tests were performed in a fime hood During cold testing, several tests were performed on individual components of the process to complete, a series of `hot' tests was designed to process irradiated targets. These were designed to optimize the process, identify problems prior to processing higher inventory targets, and to the shielded containment box (SCB). Table 1 is a summary of the tests performed prior to the Test Target Power Post irradiation Total inventory 99M0 inventory (kW)/ Irradiation decay (hrs) (TBq*) /decay (TBq)/decay Time (hrs) inventory (TBq) inventory(TBq) in the processing boxes as color comparisons. Product quality control testing was conducted for all the tests and the results were compared to The production process generates a high activity acidic liquid

  5. Thermoluminescence dating of Hawaiian basalt

    USGS Publications Warehouse

    May, Rodd James

    1979-01-01

    The thermoluminescence (TL) properties of plagioclase separates from 11 independently dated alkalic basalts 4,500 years to 3.3 million years old and 17 tholeiitic basalts 16 years to 450,000 years old from the Hawaiian Islands were investigated for the purpose of developing a TL dating method for young volcanic rocks. Ratios of natural to artificial TL intensity, when normalized for natural radiation dose rates, were used to quantify the thermoluminescence response of individual samples for age-determination purposes. The TL ratios for the alkalic basalt plagioclase were found to increase with age at a predictable exponential rate that permits the use of the equation for the best-fit line through a plot of the TL ratios relative to known age as a TL age equation. The equation is applicable to rocks ranging in composition from basaltic andesite to trachyte over the age range from about 2,000 to at least 250,000 years before present (B.P.). The TL ages for samples older than 50,000 years have a calculated precision of less than :t 10 percent and a potential estimated accuracy relative to potassium-argon ages of approximately :t 10 percent. An attempt to develop a similar dating curve for the tholeiitic basalts was not as successful, primarily because the dose rates are on the average lower than those for the alkalic basalts by a factor of 6, resulting in lower TL intensities in the tholeiitic basalts for samples of equivalent age, and also because the age distribution of dated material is inadequate. The basic TL properties of the plagioclase from the two rock types are similar, however, and TL dating of tholeiitic basalts should eventually be feasible over the age range 10,000 to at least 200,000 years B.P. The average composition of the plagioclase separates from the alkalic basalts ranges from oligoclase to andesine; compositional variations within this range have no apparent effect on the TL ratios. The average composition of the plagioclase from the tholeiitic

  6. Upgrading the Laboratory Preparation of High School Teachers

    ERIC Educational Resources Information Center

    Powers, Jack W.; Scamehorn, Richard G.

    1970-01-01

    Describes a college program designed to upgrade the laboratory experience of selected high school chemistry teachers. Small groups of teachers work with college faculty on chemistry problems each weekend. Problems investigated include the use of pH meters, X-ray diffraction, computers, and experiments in chromatography, spectroscopy radiochemistry…

  7. A Three-Step Laboratory Sequence to Prepare a Carbene Complex of Silver(I) Chloride

    ERIC Educational Resources Information Center

    Canal, John P.; Ramnial, Taramatee; Langlois, Lisa D.; Abernethy, Colin D.; Clyburne, Jason A. C.

    2008-01-01

    We have developed a multistep inorganic synthesis experiment for our second-year undergraduate teaching laboratory that introduces students to modern organometallic chemistry. The ligands are prepared in two simple steps and the preparation of an air-stable silver carbene complex is accomplished in the third step. The students are introduced to…

  8. Preparation, characterization and efficiency of nanoencapsulated imidacloprid under laboratory conditions.

    PubMed

    Memarizadeh, Nargess; Ghadamyari, Mohammad; Adeli, Mohsen; Talebi, Khalil

    2014-09-01

    In this work, nano-imidacloprid was prepared by direct encapsulation with ABA triblock linear dendritic copolymers composed of poly(citric acid) (PCA) as A block and poly(ethylene glycol) (PEG) as B block. Nanocapsules of imidacloprid were characterized using spectroscopy, microscopy and thermal analysis. The encapsulation process was performed by self-assembly of PCA-PEG-PCA in the presence of imidacloprid in different solvents. Comparison of the TEM images of nano-imidacloprid prepared in ethanol and water showed that, during the first day, self-assemblies appeared as small particles with an average size of 10-20nm. Depending upon the type of solvent, the time and concentration, morphology and size of the nano-imidacloprid varied from fiber-like to globular to tubular from 10nm to several mm in size. Higher loading capacity and slower release rate of imidacloprid from nano-imidacloprid at optimum pH of Glyphodes pyloalis׳s gut (pH=10) compared to neutral pH confirmed the selective and controllable action of nano-imidacloprid. Results of bioassays on the model insect showed that by using the nanoform of imidacloprid, essential dosage of pesticide and environmental risk decreased significantly and indicated good performance for this formulation.

  9. [LABORATORY AND EXPERIMENTAL STUDY OF THE COMPLEX PROBIOTIC PREPARATION "BIFILACT-BILS" IN CAPSULATED FORM].

    PubMed

    Neschislyaev, V A; Stolbova, M G; Mokin, P A; Orlova, E V; Ershov, A E

    2016-01-01

    The composition and technology of complex probiotic in hard gelatin capsules was developed in Perm Branch "Biomed" of "Microgen" State Company. The preparation contains three production strains: Lactobacillus plantarum 8P-A3, L. acidophilus K3W24 and Bifidobacterium bifidum 1. Laboratory and experimental (preclinical) study of the probiotic included investigation of the antagonistic activity, "acute" and "chronic" toxicity, the effect of the preparation on histology and hematology of laboratory animals. The result of these studies suggested of the probiotic had high inhibitory activity against pathogenic microflora when compared with probiotic monopreparations and had no toxic effects on laboratory animals.

  10. Thermoluminescence glow curve analysis and CGCD method for erbium doped CaZrO3 phosphor

    NASA Astrophysics Data System (ADS)

    Tiwari, Ratnesh; Chopra, Seema

    2016-05-01

    The manuscript report the synthesis, thermoluminescence study at fixed concentration of Er3+ (1 mol%) doped CaZrO3 phosphor. The phosphors were prepared by modified solid state reaction method. The powder sample was characterized by thermoluminescence (TL) glow curve analysis. In TL glow curve the optimized concentration in 1mol% for UV irradiated sample. The kinetic parameters were calculated by computerized glow curve deconvolution (CGCD) techniaue. Trapping parameters gives the information of dosimetry loss in prepared phosphor and its usability in environmental monitoring and for personal monitoring. CGCD is the advance tool for analysis of complicated TL glow curves.

  11. Modeling of the thermoluminescence mechanisms in ZrO₂.

    PubMed

    Kadari, Ahmed; Kadri, Dahane

    2013-12-01

    In this paper, simulations of thermoluminescence experiments are carried out using the comprehensive model for thermoluminescence cited in the literature by several authors, for both natural and laboratory irradiated aliquots. In the present work, we propose a possible, alternative model to explain the thermoluminescence (TL) process in zirconium oxide (ZrO2). The model includes four trapping states and one recombination center (4T1C model). The aim of the present study is to present a model that, by using as guess values the parameters obtained by employing the GOK model, fits very well the experimental glow curve. It is a goal point that the physical model does not need to resort to the quasi-equilibrium approximation. The results of these simulations are in general qualitative agreement with the experiments and confirm that the proposed model in this study presents a good explanation of these phenomena. A linear behavior was also observed between the response and dose range from 1×10(9) to 9×10(9)cm(-3).

  12. Integration of Video-Based Demonstrations to Prepare Students for the Organic Chemistry Laboratory

    NASA Astrophysics Data System (ADS)

    Nadelson, Louis S.; Scaggs, Jonathan; Sheffield, Colin; McDougal, Owen M.

    2015-08-01

    Consistent, high-quality introductions to organic chemistry laboratory techniques effectively and efficiently support student learning in the organic chemistry laboratory. In this work, we developed and deployed a series of instructional videos to communicate core laboratory techniques and concepts. Using a quasi-experimental design, we tested the videos in five traditional laboratory experiments by integrating them with the standard pre-laboratory student preparation presentations and instructor demonstrations. We assessed the influence of the videos on student laboratory knowledge and performance, using sections of students who did not view the videos as the control. Our analysis of pre-quizzes revealed the control group had equivalent scores to the treatment group, while the post-quiz results show consistently greater learning gains for the treatment group. Additionally, the students who watched the videos as part of their pre-laboratory instruction completed their experiments in less time.

  13. Method for detecting radiation dose utilizing thermoluminescent material

    DOEpatents

    Miller, Steven D.; McDonald, Joseph C.; Eichner, Fred N.; Tomeraasen, Paul L.

    1991-01-01

    The amount of ionizing radiation to which a thermoluminescent material has been exposed is determined by first cooling the thermoluminescent material to a cryogenic temperature. The thermoluminescent material is then optically stimulated by exposure to ultraviolet light. Visible light emitted by the thermoluminescent material as it is allowed to warm up to room temperature is detected and counted. The thermoluminescent material may be annealed by exposure to ultraviolet light.

  14. Method for detecting radiation dose utilizing thermoluminescent material

    DOEpatents

    Miller, S.D.; McDonald, J.C.; Eichner, F.N.; Durham, J.S.

    1992-08-04

    The amount of ionizing radiation to which a thermoluminescent material has been exposed is determined by first cooling the thermoluminescent material and then optically stimulating the thermoluminescent material by exposure to light. Visible light emitted by the thermoluminescent material as it is allowed to warm up to room temperature is detected and counted. The thermoluminescent material may be annealed by exposure to ultraviolet light. 5 figs.

  15. A thermoluminescent method for aerosol characterization

    NASA Technical Reports Server (NTRS)

    Long, E. R., Jr.; Rogowski, R. S.

    1976-01-01

    A thermoluminescent method has been used to study the interactions of aerosols with ozone. The preliminary results show that ozone reacts with many compounds found in aerosols, and that the thermoluminescence curves obtained from ozonated aerosols are characteristic of the aerosol. The results suggest several important applications of the thermoluminescent method: development of a detector for identification of effluent sources; a sensitive experimental tool for study of heterogeneous chemistry; evaluation of importance of aerosols in atmospheric chemistry; and study of formation of toxic, electronically excited species in airborne particles.

  16. Habitability Assessment on Earth in Preparation for Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Conrad, Pamela; Mahaffy, Paul

    NASA's upcoming Mars Science Laboratory mission is designed to explore and quantitatively assess a local region on the surface of Mars as a potential habitat for life, past or present. In advance of this complex mission, we are developing metrics from which to frame such an assess-ment. Evaluation of habitability potential is clearly different and more challenging than direct measurement of a discrete potential such as a voltage, which is a single parameter expressing the magnitude of a difference between a ground state and a measurable charge. Habitability potential is likely to require measurement of several parameters whose relationships determine the threshold value above which an environment may be deemed habitable in some regard. On Earth, in the continuum from uninhabitable to inhabited, one can measure environmental parameters that co-vary with biological parameters such as total biomass, functional diversity and/or ecotype along that binary join. Recognition of this statistical association facilitates development of predictive tools for assessment of habitability potential in environments that fall in between the end members of the habitability spectrum. The success of a habitabil-ity investigation on Mars depends upon development of criteria that can be agreed upon by the scientific community that will enable interpretation of the data from experiments on Mars within the context of a scalar notion of habitability, which we describe in this report. The scalar approach involves (1) measurement of physical, chemical and biological features of the candidate environment, (2) normalization of the scales over which they vary and (3) evaluation of their covariance. Inclusion of biological measurements, e.g., total biomass, diversity, ecotype, etc., serves as a benchmark in Earth environments, and the subsequent step in a campaign to develop a habitability scale involves measuring and analyzing only the chemical and physical environmental parameters, then

  17. [Thermoluminescence characteristics of Lu2SiO5 : Ce phosphors].

    PubMed

    Wu, Fei; Liu, Xiao-lin; Gu, Mu; Ni, Chen; Huang, Shi-ming; Liu, Bo

    2012-02-01

    To investigate the origin of the thermoluminescence at high temperature, Lu2SiO5 : Ce0.006 (LSO : Ce) phosphors were prepared by sol-gel chemistry in air and graphite respectively. The patterns of X-ray diffraction, excitation and emission spectra and thermoluminescence curves of these samples were analyzed. In comparison with the phosphors prepared in the air, the luminescence intensity was improved and the thermoluminescence peak at 598 K was restrained for the sample prepared in graphite. It was found that the thermoluminescence peak at 598 K was relevant to Ce4+. In order to achieve more evidences, LSO : Ce0.006, K(x) (x = 0.01-0.08) phosphors were prepared. The structures and spectra of K(+) -codoped samples were also studied. By codoping with K+ ions, the luminescence intensity of LSO : Ce phosphor could be enhanced distinctly, but the crystallinity was not improved. The results of the K(+) -codoped LSO: Ce exhibited that K(+) -codoping could improve the concentration of oxygen vacancy and restrain the peak at 598 K. When K+ ion occupied the position of Lu3+, more oxygen vacancies could be created and Ce4+ turned into Ce3+ simultaneously due to the balance of electric charge, which was consistent with the result of the thermoluminescence. So it can also come to the conclusion that the thermoluminescence peak at 598 K was relevant to Ce4+. The reason for K+ ions enhancing the intensity of LSO : Ce can be attributed to the improvement of concentration ratio for Ce3+/Ce4+.

  18. The impact of standard preparation practice on the runoff and soil erosion rates under laboratory conditions

    NASA Astrophysics Data System (ADS)

    Khaledi Darvishan, Abdulvahed; Homayounfar, Vafa; Hamidreza Sadeghi, Seyed

    2016-09-01

    The use of laboratory methods in soil erosion studies, rainfall simulation experiments, Gerlach troughs, and other measurements such as ring infiltrometer has been recently considered more and more because of many advantages in controlling rainfall properties and high accuracy of sampling and measurements. However, different stages of soil removal, transfer, preparation and placement in laboratory plots cause significant changes in soil structure and, subsequently, the results of runoff, sediment concentration and soil loss. Knowing the rate of changes in sediment concentration and soil loss variables with respect to the soil preparation for laboratory studies is therefore inevitable to generalize the laboratory results to field conditions. However, there has been little attention given to evaluate the effects of soil preparation on sediment variables. The present study was therefore conducted to compare sediment concentration and soil loss in natural and prepared soil. To achieve the study purposes, 18 field 1 × 1 m plots were adopted in an 18 % gradient slope with sandy-clay-loam soil in the Kojour watershed, northern Iran. A portable rainfall simulator was then used to simulate rainfall events using one or two nozzles of BEX: 3/8 S24W for various rainfall intensities with a constant height of 3 m above the soil surface. Three rainfall intensities of 40, 60 and 80 mm h-1 were simulated on both prepared and natural soil treatments with three replications. The sediment concentration and soil loss at five 3 min intervals after time to runoff were then measured. The results showed the significant increasing effects of soil preparation (p ≤ 0.01) on the average sediment concentration and soil loss. The increasing rates of runoff coefficient, sediment concentration and soil loss due to the study soil preparation method for laboratory soil erosion plots were 179, 183 and 1050 % (2.79, 2.83 and 11.50 times), respectively.

  19. Preparing nursing students for contemporary practice: restructuring the psychomotor skills laboratory.

    PubMed

    Snyder, M D; Fitzloff, B M; Fiedler, R; Lambke, M R

    2000-05-01

    The restructured laboratory experience offered a safe environment that supported student experimentation with psychomotor skills and self-initiated approaches to problem solving. Restructuring psychomotor laboratory experiences with emphasis on communication and conceptualization of principles supported students to begin addressing clinical problems with flexibility, creativity, and the premise for lifelong skill acquisition. Students who have skills that extend beyond technique will inevitably be better prepared to meet the demands of health care systems and patients now and in the future.

  20. Rate-limiting hydrodynamic resistance for controlled reagent delivery for laboratory solution preparation.

    PubMed

    Oruganti, Prasad; Gratzl, Miklós

    2007-03-15

    The need for precise delivery of minute quantities of substances for solution preparation and other applications is well-known in research, clinical, industrial, and environmental settings. Currently available techniques for solution preparation in the laboratory include traditional transfer pipettes, micropipettes based on air displacement, and motorized devices using some form of a piston system. These techniques control the amount delivered by controlling the delivered volume. In this work we test the practicality of the concept of using a constant rate-limiting hydrodynamic resistance to achieve controlled reagent flow for solution preparation. The delivered amount is determined in this approach by time, pressure, flow resistance, or a combination of these. Good results are achieved comparable to conventional techniques without the use of fine mechanical instrumentation. This approach holds promise as an alternative to current methods of solution preparation and reagent delivery for routine laboratory use.

  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. Online Graduates in Clinical Laboratory Sciences: Are They Prepared for the Workplace?

    ERIC Educational Resources Information Center

    Perry, Jennifer D.

    2014-01-01

    Online programs are increasing in the field of clinical laboratory sciences (CLS), however there is limited research regarding how well prepared online CLS program graduates are for the workplace, given that the field is highly hands-on skills based. Prior research suggests that online CLS graduates perform as well as their traditional graduate…

  3. TECHNIQUES OF TAPE PREPARATION AND DUPLICATION, WITH SUGGESTIONS FOR A LANGUAGE LABORATORY.

    ERIC Educational Resources Information Center

    Kansas State Dept. of Public Instruction, Topeka.

    PART ONE OF THIS BULLETIN PROVIDES HELP IN THE TWO CRITICAL AREAS OF MASTER TAPE PREPARATION AND DUPLICATION. SUPPLEMENTED BY NUMEROUS PHOTOGRAPHS AND DIAGRAMS OF EQUIPMENT AND DUPLICATION TECHNIQUES, THE BULLETIN DESCRIBES MASTER PROGRAM DUPLICATION USING LANGUAGE LABORATORY EQUIPMENT, A PROFESSIONAL MASS DUPLICATOR, A TAPE RECORDER, A RECORD…

  4. Preparation, control, and use of standard operating procedures in a space simulation laboratory

    NASA Technical Reports Server (NTRS)

    Parish, R. P., Jr.

    1975-01-01

    The degree of success in the operation of a space simulation laboratory is a direct function of the role of its standard operating procedures. Their proper use in a thermal vacuum test effects a wellrun test program. Preparation and procedure control are discussed.

  5. Thermoluminescence property of nano scale Al2O3: C by combustion method

    NASA Astrophysics Data System (ADS)

    Bharthasaradhi, R.; Nehru, L. C.

    2016-05-01

    In this study, thermoluminescence dosimetry material of carbon doped aluminium oxide by combustion method using Aluminium nitrate and Glycine. The Structure of the prepared Sample was carried out by XRD. The sample was nano crystalline in nature. Having hexagonal structure with unit cell parameters a=4.75Å, C=12.99Å. The surface morphology of the prepared nanopowder was carried out through (SEM). The morphology of the prepared sample is platelet structure and functional group analysis carried out through FT-IR Spectrum. The prepared sample was irradiated through γ-ray CO60 (100Gy) was used as γ-ray source. The thermoluminescence glow curve of the irradiated sample showed an isolated peak at around 200°C. The result suggest the prepared nanopowder is suitable for medical radiation dosimetry.

  6. National and international standards and calibration of thermoluminescence dosimetry systems.

    PubMed

    Soares, C G

    2002-01-01

    Radiation protection for radiation workers, the public, and the environment is of international concern. The use of thermoluminescence dosemeters (TLD) is an acceptable method for dose recording in most countries. For reasons of consistency and data gathering (research) it is important that a Sievert (Sv) in one part of the world equals an Sv on the other side of the globe. To this end, much work has gone into the development of standards and calibration practices for TLD systems so that they compare not only with similar systems, but also with other forms of radiation measurement. While most national laboratories provide calibration services for these systems some, as in the United States, depend on services of secondary calibration laboratories that are traceable to the national laboratories through accreditation programmes. The purpose of this paper is to explain how TLD measurements are traceable to their respective national standards for both personnel and environmental dosimetry.

  7. Teaching Laboratory and Research Skills as Preparation for Careers in Science and Education

    NASA Astrophysics Data System (ADS)

    Thoms, Brian

    2007-03-01

    Recipients of bachelor's degrees in physics have identified lab skills, team work, and research skills as abilities necessary for success in their jobs. However, they also report having received less than adequate preparation in these areas during their college careers. We report on the redesign of a junior physics-major modern physics laboratory course into an inquiry-based, research-like laboratory course. The overall strategy was such as to require the students to approach the experiments in a research-like fashion. In addition, experiments which explore materials properties which can't be looked up in textbooks, e.g. Hall Effect, have been added to further emphasize a research-like approach to the investigations. Laboratory reporting requirements were written to closely reproduce current practices in scientific journals. Assessment of the redesign was performed through surveys of current and graduated students and through comparison of laboratory reports.

  8. Preparation of bone samples in the Gliwice Radiocarbon Laboratory for AMS radiocarbon dating.

    PubMed

    Piotrowska, N; Goslar, T

    2002-12-01

    In the Gliwice Radiocarbon Laboratory, a system for preparation of samples for AMS dating has been built. At first it was used to produce graphite targets from plant macrofossils and sediments. In this study we extended its capabilities with the preparation of bones. We dealt with 3 methods; the first was the classical Longin method of collagen extraction, the second one included additional treatment of powdered bone in alkali solution, while in the third one carboxyl carbon was separated from amino acids obtained after hydrolysis of protein. The suitability of the methods was tested on 2 bone samples. Most of our samples gave ages > 40 kyr BP, suggesting good performance of the adapted methods, except for one sample prepared with simple Longin method. For routine preparation of bones we chose the Longin method with additional alkali treatment.

  9. Measuring the Effectiveness of Simulations in Preparing Students for the Laboratory

    NASA Astrophysics Data System (ADS)

    Paetkau, Mark; Bissonnette, Dan; Taylor, Colin

    2013-02-01

    Computer simulations (we use the word liberally here to include applets, animations, apps, etc.) have been making steady progress as teaching tools. Large collections of simulations, created by individuals1,2 and by groups,3 are freely available. More recently, research on the effectiveness of simulations as teaching tools, particularly focused on the teaching of concepts, has been an area of interest.4,5 We have been using simulations at Thompson Rivers University (TRU) to help prepare students for the physics lab for the past five years. In work by others, simulations were used in the pre-laboratory work to prepare students on a conceptual level.6 In our case the simulations are used to help prepare students for the experimental aspect. The current work focuses on students' need to take data in the lab and how students can be prepared to efficiently obtain that data.

  10. Thermoluminescence measurement technique using millisecond temperature pulses.

    PubMed

    Manfred, Michael E; Gabriel, Nicholas T; Yukihara, Eduardo G; Talghader, Joseph J

    2010-06-01

    A measurement technique, pulsed thermoluminescence, is described which uses short thermal pulses to excite trapped carriers leading to radiative recombination. The pulses are obtained using microstructures with approximately 500 micros thermal time constants. The technique has many of the advantages of pulsed optically stimulated luminescence without the need for optical sources and filters to isolate the luminescent signal. Charge carrier traps in alpha-Al(2)O(3):C particles on microheaters were filled using 205 nm light. Temperature pulses of 10 and 50 ms were applied to the heaters and compared with a standard thermoluminescence curve taken at a ramp rate of 5 K s(-1). This produced curves of intensity verses temperature similar to standard thermoluminescence except shifted to higher temperatures. The luminescence of single particles was read multiple times with negligible loss of population. The lower limit of the duration of useful pulses appears to be limited by particle size and thermal contact between the particle and heater.

  11. Phage on tap–a quick and efficient protocol for the preparation of bacteriophage laboratory stocks

    PubMed Central

    Bonilla, Natasha; Rojas, Maria Isabel; Netto Flores Cruz, Giuliano; Hung, Shr-Hau; Rohwer, Forest

    2016-01-01

    A major limitation with traditional phage preparations is the variability in titer, salts, and bacterial contaminants between successive propagations. Here we introduce the Phage On Tap (PoT) protocol for the quick and efficient preparation of homogenous bacteriophage (phage) stocks. This method produces homogenous, laboratory-scale, high titer (up to 1010–11 PFU·ml−1), endotoxin reduced phage banks that can be used to eliminate the variability between phage propagations and improve the molecular characterizations of phage. The method consists of five major parts, including phage propagation, phage clean up by 0.22 μm filtering and chloroform treatment, phage concentration by ultrafiltration, endotoxin removal, and the preparation and storage of phage banks for continuous laboratory use. From a starting liquid lysate of > 100 mL, the PoT protocol generated a clean, homogenous, laboratory phage bank with a phage recovery efficiency of 85% within just two days. In contrast, the traditional method took upwards of five days to produce a high titer, but lower volume phage stock with a recovery efficiency of only 4%. Phage banks can be further purified for the removal of bacterial endotoxins, reducing endotoxin concentrations by over 3,000-fold while maintaining phage titer. The PoT protocol focused on T-like phages, but is broadly applicable to a variety of phages that can be propagated to sufficient titer, producing homogenous, high titer phage banks that are applicable for molecular and cellular assays. PMID:27547567

  12. Correlation between thermoluminescence and radiation damage in bismuth germanate

    SciTech Connect

    Melcher, C.L.

    1985-02-01

    Thermoluminescence properties of bismuth germanate and their relationship to radiation damage characteristics have been investigated. Thermoluminescence and radiation damage in bismuth germanate display several similar properties including similar responses as a function of radiation dose, similar saturation levels, and similar decay times. Also a correlation was found between the thermoluminescence sensitivities and radiation damage sensitivities of four different crystals. The traps responsible for the radiation damage and those which store the thermoluminescence signal appear to be either closely related or actually the same traps. Four trapping centers can be seen in the thermoluminescence glow curves. The depth of the dominant trap is 1.1 eV. 10 references.

  13. Rock cooling history using thermoluminescence of natural radiation dosimeter

    NASA Astrophysics Data System (ADS)

    Biswas, Rabiul; Herman, Frederic

    2016-04-01

    Recently, optical luminescences from quartz and feldspar have been proposed to have great potential in low temperature thermochronology (<100°C). The present study aims to explore thermoluminescence (TL) of feldspar to determine cooling history of rock. The advantage of thermoluminescence over optical luminesce is single TL glow curve has different thermal and athermal stability at different temperature of the glow curve, which can be determined by computerized glow curve deconvolution (CGCD) method and estimation of rate of anomalous fading in the laboratory. The rock samples were collected from Alex Knob of Franz Josef glacier, New Zealand, which is expected to be one of the rapidly exhuming settings in Southern Alps. The natural luminescence levels, which are in the dynamic equilibrium because of competition between growth due to ambient radioactivity and decay due thermal and athermal loss, are determined using multiple aliquot regeneration (MAR) protocol. Multiple thermal signals with wide range of thermal stability, extracted from composite glow curve, particularly low temperature part which is more sensitive to ambient temperature, is promising for better constraint on late stage cooling history.

  14. Thermoluminescence dosimeters with narrow bandpass filters

    SciTech Connect

    Walker, Scottie W.

    2004-07-20

    A dosimetry method exposes more than one thermoluminescence crystals to radiation without using conventional filters, and reads the energy stored in the crystals by converting the energy to light in a conventional manner, and then filters each crystal output in a different portion of the spectrum generated by the crystals.

  15. Dating volcanic ash by use of thermoluminescence

    SciTech Connect

    Berger, G.W. )

    1992-01-01

    The fine-silt-sized (4-11 {mu}m) grains of glass separated from four samples of independently dated, 8 to 400 ka, tephra beds provide accurate thermoluminescence (TL) ages. This demonstration of reliable TL dating of volcanic glass provides a new tephrochronometer for deposits spanning the Holocene to middle Pleistocene age range.

  16. Natural thermoluminescence of Antarctic meteorites and related studies

    NASA Technical Reports Server (NTRS)

    Benoit, Paul H.; Sears, Derek W. G.

    1998-01-01

    The natural thermoluminescence (TL) laboratory's primary purpose is to provide data on newly recovered Antarctic meteorites that can be included in discovery announcements and to investigate the scientific implications of the data. Natural TL levels of meteorites are indicators of recent thermal history and terrestrial history, and the data can be used to study the orbital/radiation history of groups of meteorites (e.g., H chondrites) or to study the processes leading to the concentration of meteorites at certain sites in Antarctica. An important application of these data is the identification of fragments, or "pairs" of meteorites produced during atmospheric passage or during terrestrial weathering. Thermoluminescence data are particularly useful for pairing within the most common meteorite classes, which typically exhibit very limited petrographic and chemical diversity. Although not originally part of the laboratory's objectives, TL data are also useful in the identification and classification of petrographically or mineralogically unusual meteorites, including unequilibrated ordinary chondrites and some basaltic achondrites. In support of its primary mission, the laboratory also engages in TL studies of modern falls, finds from hot deserts, and terrestrial analogs and conducts detailed studies of the TL properties of certain classes of meteorites. These studies include the measurement of TL profiles in meteorites, the determination of TL levels of finds from the Sahara and the Nullarbor region of Australia, and comparison of TL data to other indicators of irradiation or terrestrial history, such as cosmogenic noble gas and radionuclide abundances. Our current work can be divided into five subcategories, (a) TL survey of Antarctic meteorites, (b) pairing and field relations of Antarctic meteorites, (c) characterization of TL systematics of meteorites, (d) comparison of natural TL and other terrestrial age indicators for Antarctic meteorites, and for meteorites

  17. Spectrophotometric determination of meclizine hydrochloride and pyridoxine hydrochloride in laboratory prepared mixtures and in their pharmaceutical preparation.

    PubMed

    Ibrahim, Maha M; Elzanfaly, Eman S; El-Zeiny, Mohamed B; Ramadan, Nesreen K; Kelani, Khadiga M

    2017-05-05

    In this paper, three rapid, simple, accurate and precise spectrophotometric methods were developed for the determination of meclizine hydrochloride in the presence of pyridoxine hydrochloride without previous separation. The methods under study are dual wavelength (DWL), ratio difference (RD) and continuous wavelet transform (CWT). On the other hand, pyridoxine hydrochloride (PYH) was determined directly at 291nm. The methods obey Beer's law in the range of (5-50μg/mL) for both compounds. All the methods were validated according to the ICH guidelines where the accuracy was found to be 98.29, 99.59, 100.42 and 100.62% for DWL, RD, CWT and PYH; respectively. Moreover the precision of the methods were calculated in terms of %RSD and it was found to be 0.545, 0.372, 1.287 and 0.759 for DWL, RD,CWT and PYH; respectively. The selectivity of the proposed methods was tested using laboratory prepared mixtures and assessed by applying the standard addition technique. So, they can be used for the routine analysis of pyridoxine hydrochloride and meclizine hydrochloride in quality-control laboratories.

  18. Determination of thermoluminescence kinetic parameters of terbium-doped zirconium oxide

    NASA Astrophysics Data System (ADS)

    Rivera, T.; Azorín, J.; Falcony, C.; Martínez, E.; García, M.

    2001-06-01

    In recent years considerable importance has been attached to zirconium oxide doped with rare earth (ZrO 2 : RE) thin films due to their desirable characteristics for use in UV dosimetry. In our laboratories we have developed a method to prepare ZrO 2 : RE thin films. Dosimetric characteristics of these materials have been reported previously (Azorin et al., Radiat. Meas. 29 (1998) 315; Radiat. Prot. Dosim. 85 (1999) 317) and results of these have stimulated continued development and analysis of the thermoluminescence mechanism. Two important parameters to be determined in TL studies are the activation energy ( E) and the frequency factor ( s). This paper presents the results of determining kinetic parameters of terbium-doped zirconium oxide (ZrO 2 : Tb) thin films, exposed to 260 nm UV light, using the Lushchik (Sov. Phys. JETF 3 (1956) 390) and Chen (J. Appl. Phys. 40 (1969) 570; J. Electrochem. Soc. 166 (1969) 1254) methods. Kinetic analysis of the glow curve shows second order kinetics for both the first and second glow peaks.

  19. Occupational cocaine exposure of crime laboratory personnel preparing training aids for a military working dog program.

    PubMed

    Gehlhausen, Jay M; Klette, Kevin L; Stout, Peter R; Given, JoAnn

    2003-10-01

    The potential for passive cocaine exposure was evaluated in crime laboratory employees preparing training aids for a military working dog program (MWD). The primary goal of the study was to elucidate the routes of exposure and implement procedural changes that would minimize this risk. Several work environments and laboratory procedures were examined by monitoring personal breathing zones (PBZ), ambient airborne cocaine levels in the laboratory spaces, and urinary levels of the primary cocaine metabolite, benzoylecgonine. The study was performed initially using current laboratory procedures to establish a baseline and to identify potential sources of exposure. A subsequent study was performed to determine the effectiveness of the follow-up procedure in reducing exposure. As a result of the changes, the 8-h time weighted averages (TWAs) were 40 to 80% lower in the follow-up study as compared to the baseline assessment. Dermal absorption and PBZ inhalation of cocaine during manufacture were likely the most significant source of cocaine exposure. Ambient airborne cocaine may have also contributed to the total exposure, but for most observations, the concentrations were significantly less than those determined from PBZ monitoring. The maximum ambient cocaine concentration was 0.0144 mg/m(3) compared to a maximum of 0.4004 mg/m(3) observed during PBZ monitoring. Occupational exposure decreased in the follow-up study because of the proper use of personal protective equipment and improvements in engineering controls.

  20. Administration of substances to laboratory animals: equipment considerations, vehicle selection, and solute preparation.

    PubMed

    Turner, Patricia V; Pekow, Cynthia; Vasbinder, Mary Ann; Brabb, Thea

    2011-09-01

    Administration of substances to laboratory animals requires careful consideration and planning to optimize delivery of the agent to the animal while minimizing potential adverse experiences from the procedure. The equipment selected to deliver substances to animals depends on the length of the study and the nature of the material being administered. This selection provides a significant opportunity for refining animal treatment. Similarly, when substances are administered as solutions or suspensions, attention should be given to selection of vehicles and methods used for preparing the solutions and suspensions. The research team, veterinarian, technical personnel, and IACUC members should be aware of reasons underlying selection of equipment for substance delivery and should consider carefully how substances will be prepared and stored prior to administration to animals. Failure to consider these factors during experimental planning may result in unintentional adverse effects on experimental animals and confounded results.

  1. Food adulteration analysis without laboratory prepared or determined reference food adulterant values.

    PubMed

    Kalivas, John H; Georgiou, Constantinos A; Moira, Marianna; Tsafaras, Ilias; Petrakis, Eleftherios A; Mousdis, George A

    2014-04-01

    Quantitative analysis of food adulterants is an important health and economic issue that needs to be fast and simple. Spectroscopy has significantly reduced analysis time. However, still needed are preparations of analyte calibration samples matrix matched to prediction samples which can be laborious and costly. Reported in this paper is the application of a newly developed pure component Tikhonov regularization (PCTR) process that does not require laboratory prepared or reference analysis methods, and hence, is a greener calibration method. The PCTR method requires an analyte pure component spectrum and non-analyte spectra. As a food analysis example, synchronous fluorescence spectra of extra virgin olive oil samples adulterated with sunflower oil is used. Results are shown to be better than those obtained using ridge regression with reference calibration samples. The flexibility of PCTR allows including reference samples and is generic for use with other instrumental methods and food products.

  2. Administration of Substances to Laboratory Animals: Equipment Considerations, Vehicle Selection, and Solute Preparation

    PubMed Central

    Turner, Patricia V; Pekow, Cynthia; Vasbinder, Mary Ann; Brabb, Thea

    2011-01-01

    Administration of substances to laboratory animals requires careful consideration and planning to optimize delivery of the agent to the animal while minimizing potential adverse experiences from the procedure. The equipment selected to deliver substances to animals depends on the length of the study and the nature of the material being administered. This selection provides a significant opportunity for refining animal treatment. Similarly, when substances are administered as solutions or suspensions, attention should be given to selection of vehicles and methods used for preparing the solutions and suspensions. The research team, veterinarian, technical personnel, and IACUC members should be aware of reasons underlying selection of equipment for substance delivery and should consider carefully how substances will be prepared and stored prior to administration to animals. Failure to consider these factors during experimental planning may result in unintentional adverse effects on experimental animals and confounded results. PMID:22330706

  3. Validation of the Sysmex sp-1000i automated slide preparer-stainer in a clinical laboratory

    PubMed Central

    de Bitencourt, Eberson Damião dos Santos; Voegeli, Carlos Franco; Onzi, Gabriela dos Santos; Boscato, Sara Cardoso; Ghem, Carine; Munhoz, Terezinha

    2013-01-01

    Background The speed and quality of information have become essential items in the release of laboratory reports. The Sysmex®SP1000-I device has been developed to prepare and stain smear slides. However, for a device to be cleared for use in the laboratory routine it must pass through a validation process. Objective To evaluate the performance and reliability of the Sysmex® SP-1000i slide preparer-stainer incorporated into the routine of a hospital laboratory in Porto Alegre. Methods Peripheral blood samples of patients attending the laboratory for ambulatory exams with leukocyte counts between 7000/°L and 12,000/°L were evaluated, independent of gender and age. Two slides were prepared for each sample using the Sysmex® SP-1000i equipment; one of the slides was used to perform quality control tests using the CellaVision® DM96 device, and the other slide was used to compare pre-classification by the same device and the classification performed by a pharmacist-biochemist. Results The results of all the slides used as controls were acceptable according to the quality control test as established by the manufacturer of the device. In the comparison between the automated pre-classification and the classification made by the professional, there was an acceptable variation in the differential counts of leukocytes for 90% of the analyzed slides. Pearson correlation coefficient showed a strong correlation for band neutrophils (r = 0.802; p-value < 0.001), segmented neutrophils (r = 0.963; p-value < 0.001), eosinophils (r = 0.958; p-value < 0.001), lymphocytes (r = 0.985; p-value < 0.001) and atypical lymphocytes (r = 0.866; p-value < 0.001) using both methods. The red blood cell analysis was adequate for all slides analyzed by the equipment and by the professional. Conclusion The new Sysmex®SP1000-i methodology was found to be reliable, fast and safe for the routines of medium and large laboratories, improving the quality of microscopic analysis in complete blood

  4. Detection of irradiated mushrooms and kiwi fruits by thermoluminescence measurement

    NASA Astrophysics Data System (ADS)

    Dangl, Th.; Leitner-Wild, E.; Hille, P.; Nowotny, R.

    1993-03-01

    Control methods for the detection of irradiated food are needed since exposure to ionizing radiation is a new technique of commercial food processing applied in many countries. A simple and rapid method for the identification of irradiated fresh kiwi fruits and mushrooms is presented. Thermoluminescence (TL) signals of irradiated dried herbs and spices are known to be due to inorganic dust particles adherent to the surface and may be used for the detection of radiation exposure. In the technique described here the discrimination between radiation exposed food samples and unirradiated samples was improved by the preparation of TL samples enriched in extraneous inorganic material and further by the determination of the optimal integration interval giving the highest signal to background ratios. This method yields a more reliable discrimination than whole sample TL techniques.

  5. KCl:Dy phosphor for thermoluminescence dosimetry of ionizing radiation.

    PubMed

    Bhujbal, P M; Dhoble, S J

    2013-01-01

    The thermoluminescence (TL) characterizations of γ-irradiated KCl:Dy phosphor for radiation dosimetry are reported. All phosphors were synthesized via a wet chemical route. Minimum fading of TL intensity is recorded in the prepared material. TL in samples containing different concentrations of Dy impurity was studied at different γ-irradiation doses. Peak TL intensities varied sublinearly with γ-ray dose in all samples, but were linear between 0.08 to 0.75 kGy for the KCl:Dy (0.1 mol%) sample. This material may be useful for dosimetry within this range of γ-ray dose. TL peak height was found to be dependant on the concentration (0.05-0.5 mol%) of added Dy in the host.

  6. Teaching Technical and Professional Skills Using a Laboratory Exercise: A Comparison of Two Methods of Plasmid Preparation

    ERIC Educational Resources Information Center

    Brown, Lesley R.

    2006-01-01

    This laboratory exercise encourages upper level biochemistry students to build and expand upon previously developed laboratory skills and knowledge as they conduct a comparison of two methods of plasmid preparation based upon cost, quality of product, production time, and environmental impact. Besides creating an environment that mimics a more…

  7. Test plan for preparing the Rapid Transuranic Monitoring Laboratory for field deployment

    SciTech Connect

    McIsaac, C.V.; Sill, C.W.; Gehrke, R.J.; Killian, E.W.; Watts, K.D.

    1994-04-01

    This plan describes experimental work that will be performed during fiscal year 1994 to prepare the Rapid Transuranic Monitoring Laboratory (RTML) for routine field use by US Department of Energy (DOE) Environmental Restoration and Waste Management programs. The RTML is a mobile, field-deployable laboratory developed at the Idaho National Engineering Laboratory (INEL) that provides a rapid, cost-effective means of characterizing and monitoring radioactive waste remediation sites for low-level radioactive contaminants. Analytical instruments currently installed in the RTML include an extended-range, germanium photon analysis spectrometer with an automatic sample changer; two, large-area, ionization chamber alpha spectrometers; and four alpha continuous air monitors. The RTML was field tested at the INEL during June 1993 in conjunction with the Buried Waste Integrated Demonstration`s remote retrieval demonstration. The major tasks described in this test plan are to (a) evaluate the beta detectors for use in screening soil samples for {sup 90}Sr, (b) upgrade the alpha spectral analysis software programs, and (c) upgrade the photon spectral analysis software programs.

  8. Thermoluminescence of Uranyl Salts Under Mechano-destruction

    NASA Astrophysics Data System (ADS)

    Tukhbatullin, A. A.; Sharipov, G. L.

    The thermoluminescence of the salts UO2(NO3)2·6H2O and UO2(ClO4)2·6H2O that have been previously treated mechanically at 77 K was studied. A maximum was observed in thermoluminescence curve at 80-90 K. The thermoluminescence peak intensity depends on duration of mechanical treatment at 77 K. The trap depth of glow centers has been determined using experimental thermoluminescence curves. The calculated activation energy ETL and frequency factor p0 were 0.21 eV and 1010 s-1, respectively

  9. Photo and thermoluminescence of KMgSO4 F: Ce and :Mn phosphors.

    PubMed

    Poddar, Anuradha; Gedam, S C; Dhoble, S J

    2015-06-01

    KMgSO4 F:Ce and KMgSO4 F:Mn phosphors were prepared by a wet chemical method and studied for their photoluminescence (PL) and thermoluminescence (TL) characteristics. PL emission of KMgSO4 F:Ce peaked at around 440 nm for the excitation at 377 nm due to 5d → 4f transition, while KMgSO4 F:Mn had a peak at 540 nm for an excitation at 363 nm and 247 nm due to (4) T1g  → (6) A1g transition. The phosphors also showed good thermoluminescence characteristics when they were exposed to γ-rays at a 5 Gy dose at the rate of 0.36 kGyh(-1) . KMgSO4 F:Ce exhibited a single thermoluminescence (TL) peak at around 167 °C and KMgSO4 F:Mn also exhibited a single TL peak at around 177 °C. Possible trapping parameters such as order of kinetics (b), the geometrical factor (μg ), the frequency factor (s) and the activation energy were also evaluated by Chen's half width method. This article discusses fundamental PL and TL characteristics in inorganic fluoride material activated by Ce(3+) and Mn(2+) ions and prepared by a wet chemical method.

  10. Photoluminescence and thermoluminescence studies of CaAl2O4:Dy(3+) phosphor.

    PubMed

    Ziyauddin, Mohammad; Tigga, Shalinta; Brahme, Nameeta; Bisen, D P

    2016-02-01

    Calcium aluminate phosphors activated by Dy(3+) have been prepared by a combustion method at a temperature of 600°C. Photoluminescence (PL) and thermoluminescence (TL) properties of gamma-irradiated Dy-doped calcium aluminate were investigated. The PL spectrum shows a broad peak around 488 nm and 573 nm, under 347 nm excitation. Thermoluminescence studies were performed for different concentrations of Dy. Optimum intensity of photoluminescence was found for 0.02 mol% concentration of Dy. It was found that initially the peak TL intensity increases with increasing concentration of Dy in the CaAl2O4 host, attains a maximum value for 0.05 mol% concentration and decreases with further increase in the doping concentration due to concentration quenching.

  11. Teaching about citric acid cycle using plant mitochondrial preparations: Some assays for use in laboratory courses*.

    PubMed

    Vicente, Joaquim A F; Gomes-Santos, Carina S S; Sousa, Ana Paula M; Madeira, Vítor M C

    2005-03-01

    Potato tubers and turnip roots were used to prepare purified mitochondria for laboratory practical work in the teaching of the citric acid cycle (TCA cycle). Plant mitochondria are particularly advantageous over the animal fractions to demonstrate the TCA cycle enzymatic steps, by using simple techniques to measure O(2) consumption and transmembrane potential (ΔΨ). The several TCA cycle intermediates induce specific enzyme activities, which can be identified by respiratory parameters. Such a strategy is also used to evidence properties of the TCA cycle enzymes: ADP stimulation of isocitrate dehydrogenase and α-ketoglutarate dehydrogenase; activation by citrate of downstream oxidation steps, e.g. succinate dehydrogenase; and regulation of the activity of isocitrate dehydrogenase by citrate action on the citrate/isocitrate carrier. Furthermore, it has been demonstrated that, in the absence of exogenous Mg(2+) , isocitrate-dependent respiration favors the alternative oxidase pathway, as judged by changes of the ADP/O elicited by the inhibitor n-propyl galate. These are some examples of assays related with TCA cycle intermediates we can use in laboratory courses.

  12. Characterization of Laboratory Prepared Concrete Pastes Exposed to High Alkaline and High Sodium Salt Solutions

    SciTech Connect

    Langton, C. A.

    2016-06-30

    The objective of this study was to identify potential chemical degradation mechanisms for the Saltstone Disposal Unit (SDU) concretes, which over the performance life of the structures may be exposed to highly alkaline sodium salt solutions containing sulfate, hydroxide, and other potentially corrosive chemicals in salt solution and saltstone flush water, drain water, leachate and / or pore solution. The samples analyzed in this study were cement pastes prepared in the SIMCO Technologies, Inc. concrete laboratory. They were based on the paste fractions of the concretes used to construct the Saltstone Disposal Units (SDUs). SDU 1 and 4 concrete pastes were represented by the PV1 test specimens. The paste in the SDU 2, 3, 5, and 6 concrete was represented by the PV2 test specimens. SIMCO Technologies, Inc. selected the chemicals and proportions in the aggressive solutions to approximate proportions in the saltstone pore solution [2, 3, 5, and 6]. These test specimens were cured for 56 days in curing chamber before being immersed in aggressive solutions. After exposure, the samples were frozen to prevent additional chemical transport and reaction. Selected archived (retrieved from the freezer) samples were sent to the Savannah River National Laboratory (SRNL) for additional characterization using x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray (EDX) spectroscopy. Characterization results are summarized in this report. In addition, a correlation between the oxide composition of the pastes and their chemical durability in the alkaline salt solutions is provided.

  13. Method of analysis of asbestiform minerals by thermoluminescence

    DOEpatents

    Fisher, Gerald L.; Bradley, Edward W.

    1980-01-01

    A method for the qualitative and quantitative analysis of asbestiform minerals, including the steps of subjecting a sample to be analyzed to the thermoluminescent analysis, annealing the sample, subjecting the sample to ionizing radiation, and subjecting the sample to a second thermoluminescent analysis. Glow curves are derived from the two thermoluminescent analyses and their shapes then compared to established glow curves of known asbestiform minerals to identify the type of asbestiform in the sample. Also, during at least one of the analyses, the thermoluminescent response for each sample is integrated during a linear heating period of the analysis in order to derive the total thermoluminescence per milligram of sample. This total is a measure of the quantity of asbestiform in the sample and may also be used to identify the source of the sample.

  14. Thermoluminescence of Tequila-based nanodiamond.

    PubMed

    Morales, J; Bernal, R; Cruz-Vazquez, C; Salcido-Romero, E G; Castaño, V M

    2010-06-01

    Nanodiamond thin films were deposited onto Si (100) substrates using Tequila as precursor by pulsed-liquid injection chemical vapour deposition at 850 degrees C. Some samples were exposed to beta particle irradiation in the dose range from 100 to 1600 Gy, and it was found that the thermoluminescence (TL) response is a linear function of dose. The glow curve displays two maxima centred at 170 and 350 degrees C, which does not shift when dose changes, indicating that first-order kinetics processes are involved. From the results, it is concluded that the new nanodiamond films are promising high-dose TL dosimeters.

  15. Thermoluminescence of Apollo 12 lunar samples

    USGS Publications Warehouse

    Doell, Richard R.; Brent, Dalrymple G.

    1971-01-01

    Thermoluminescence (TL) glow curve and decay characteristics of Apollo 12 fines and soil samples are similar to those from Apollo 11. Interpretation of the results from the core sample is difficult because of inadequate sample, spacing, but it appears that the part of the core below about 8 cm has been undisturbed for about 104 years whereas the part of the core above 10 cm may have been disturbed by recent surface activity. TL in the Apollo 12 samples is about twice that in the Apollo 11 samples, suggesting a lower mean daytime surface temperature of a few degrees at the Apollo 12 site. ?? 1971.

  16. Thermoluminescence dating of Australian palaeo-earthquakes

    USGS Publications Warehouse

    Hutton, J.T.; Prescott, J.R.; Bowman, J.R.; Dunham, M.N.E.; Crone, A.J.; Machette, M.N.; Twidale, C.R.

    1994-01-01

    Thermoluminescence (TL) dating is a useful tool for determining the age of prehistoric earthquakes by dating deposits that are stratigraphically related to fault scarps that formed during the earthquakes. TL dating of aeolian sand in the area of the 1988 Tennant Creek, Northern Territory, earthquakes provides evidence that similar earthquakes have not ruptured the causative faults for at least 50 ka. Pilot TL measurements of deposits associated with the Roopena and Ash Ridge fault scarps near Whyalla on Eyre Peninsula, South Australia, suggest an age of 140 ka for the Quaternary deposits associated with the formation of the scarps. ?? 1994.

  17. Thermal effect on thermoluminescence response of hydroxyapatite.

    PubMed

    Zarate-Medina, J; Sandoval-Cedeño, K J; Barrera-Villatoro, A; Lemus-Ruiz, J; Rivera Montalvo, T

    2015-06-01

    This paper presents the experimental results of the thermoluminescence (TL) induced by gamma radiation in synthetic hydroxyapatite (HAp) obtained by the precipitation method, using Ca(NO3)2·4H2O and (NH4)2HPO4 and calcined at different temperatures. The structural and morphological characterization was carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. TL response as a function of gamma radiation dose was in a wide range, where intensity was enhanced in the sample annealed at 900°C, which tricalcium diphosphate (TCP) phase appear. Fading of the TL was also studied.

  18. Initial evaluation of Sandia National Laboratory-prepared crystalline silico-titanates for cesium recovery

    SciTech Connect

    Bray, L.A.; Carson, K.J.; Elovich, R.J.

    1993-10-01

    Pacific Northwest Laboratory initiated a study of a new class of inorganic ion exchange materials that selectively extracts cesium (Cs), strontium (Sr), and plutonium (Pu) from alkaline radioactive waste solutions. These materials, identified as crystalline silico-titanates (CST), were developed by scientists at the Sandia National Laboratory (SNL) and Texas A&M. This report summarizes preliminary results for the measurement of batch distribution coefficient (K{sub d}) values for the powdered CST materials compared to previously tested ion exchange materials: IONSIV IE-96 (a zeolite produced by UOP), CS-100 (an organic resin produced by Rohm and Haas), and BIB-DJ (a new resorcinol-formaldehyde organic resin produced by Boulder Scientific). Excellent results were obtained for CST inorganic exchangers that could be significant in the development of processes for the near-term pretreatment of Hanford alkaline wastes. The following observations and conclusions resulted from this study: (1) Several CST samples prepared at SNL had a higher capacity to remove Cs from solution as compared to BIB-DJ, IE-96, and CS-100. (2) Cesium distribution results showed that CST samples TAM-40, -42, -43, -70, and -74 had {lambda} values of {approximately}2,200 ({lambda} = Cs K{sub d} {times} {rho}{sub b}; where {lambda} represents the number of exchanger bed volumes of feed that can be loaded on an ion exchange column) at a pH value >14. (3) Cesium distribution values for CST exchangers doubled as the aqueous temperature decreased from 40{degrees} to 10{degrees}C. (4) Crystalline silico-titanates have the capacity to remove Cs as well as Sr and Pu from alkaline wastes unless organic complexants are present. Experimental results indicated that complexed Sr was not removed, and Pu is not expected to be removed.

  19. To the Geoportal and Beyond! Preparing the Earth Observing Laboratory's Datasets for Inter-Repository Discovery

    NASA Astrophysics Data System (ADS)

    Gordon, S.; Dattore, E.; Williams, S.

    2014-12-01

    Even when a data center makes it's datasets accessible, they can still be hard to discover if the user is unaware of the laboratory or organization the data center supports. NCAR's Earth Observing Laboratory (EOL) is no exception. In response to this problem and as an inquiry into the feasibility of inter-connecting all of NCAR's repositories at a discovery layer, ESRI's Geoportal was researched. It was determined that an implementation of Geoportal would be a good choice to build a proof of concept model of inter-repository discovery around. This collaborative project between the University of Illinois and NCAR is coordinated through the Data Curation Education in Research Centers program. This program is funded by the Institute of Museum and Library Services.Geoportal is open source software. It serves as an aggregation point for metadata catalogs of earth science datasets, with a focus on geospatial information. EOL's metadata is in static THREDDS catalogs. Geoportal can only create records from a THREDDS Data Server. The first step was to make EOL metadata more accessible by utilizing the ISO 19115-2 standard. It was also decided to create DIF records so EOL datasets could be ingested in NASA's Global Change Master Directory (GCMD). To offer records for harvest, it was decided to develop an OAI-PMH server. To make a compliant server, the OAI_DC standard was also implemented. A server was written in Perl to serve a set of static records. We created a sample set of records in ISO 19115-2, FGDC, DIF, and OAI_DC. We utilized GCMD shared vocabularies to enhance discoverability and precision. The proof of concept was tested and verified by having another NCAR laboratory's Geoportal harvest our sample set. To prepare for production, templates for each standard were developed and mapped to the database. These templates will help the automated creation of records. Once the OAI-PMH server is re-written in a Grails framework a dynamic representation of EOL

  20. Synthesis, characterization and thermoluminescence studies of (ZnS)1-x (MnTe)x nanophosphors.

    PubMed

    Pateria, Deepti; Baghel, R N; Bisen, D P; Jha, Piyush; Chandra, V K; Chandra, B P

    2017-05-01

    The present paper reports the thermoluminescence (TL) of (ZnS)1-x (MnTe)x nanophosphors that were prepared by a wet chemical synthesis method. The structure investigated by X-ray diffraction patterns confirms the formation of a sphalerite phase whose space group was found to be F 4¯3m. From XRD, TEM and SEM analyses the average sizes of the particles were found to be 12 nm, 11 nm and 15 nm, respectively. Initially the TL intensity increased with increasing values of x because the number of luminescence centres increased; however, for higher values of x the TL intensity decreased because of the concentration quenching. Thus the TL, mechanoluminescence and photoluminescence intensities are optimum for a particular value of x, that is for x = 0.05. Thermoluminescence of the (ZnS)1-x (MnTe)x nanophosphor has not been reported previously. There were two peaks seen in the thermoluminescence glow curves in which the first peak lay at 105-100 °C and the second peak lay at 183.5-178.5 °C. The activation energies for the first and second peaks were found to be 0.45 eV and 0.75 eV, respectively.

  1. Tips and traps in the 14C Bio-AMS preparation laboratory (WSam 7)

    SciTech Connect

    Buchholz, B A; Haack, K W; Stewart, P H; Vogel, J S

    1999-10-12

    Maintaining a contamination free sample preparation lab for biological 14 C AMS requires the same or more diligence as a radiocarbon dating prep lab. Isotope ratios of materials routinely range over 4-8 orders of magnitude in a single experiment, dosing solutions contain thousands of DPM and gels used to separate proteins possess 14 C ratios of 1pMC. Radiocarbon contamination is a legacy of earlier tracer work in most biological laboratories, even if they were never hot labs. Removable surface contamination can be found and monitored using swipes. Contamination can be found on any surface routinely touched: door knobs, light switches, drawer handles, water faucets. In general, all surfaces routinely touched need to be covered with paper, foil, or plastic that can be changed frequently. Shared air supplies can also present problems by distributing hot aerosols throughout a building. Aerosols can be monitored for 14 C content using graphitized coal or fullerene soot mixed with metal powder as an absorber. The monitors can be set out in work spaces for 1-2 weeks and measured by AMS with regular samples. Frequent air changes help minimize aerosol contamination in many cases. Cross contamination of samples can be minimized by using disposable plastic or glassware in the prep lab, isolating samples from the air when possible and using positive displacement pipetters.

  2. STAR: Preparing future science and math teachers through authentic research experiences at national laboratories

    NASA Astrophysics Data System (ADS)

    Keller, John; Rebar, Bryan

    2012-11-01

    The STEM Teacher and Researcher (STAR) Program provides 9-week paid summer research experiences at national research laboratories for future science and math teachers. The program, run by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the entire California State University (CSU) System, has arranged 290 research internships for 230 STEM undergraduates and credential candidates from 43 campuses over the past 6 years. The program has partnered with seven Department of Energy labs, four NASA centers, three NOAA facilities, and the National Optical Astronomy Observatory (NOAO). Primary components of the summer experience include a) conducting research with a mentor or mentor team, b) participating in weekly 2-3 hour workshops focused on translating lessons learned from summer research into classroom practice, and c) presenting a research poster or oral presentation and providing a lesson plan linked to the summer research experience. The central premise behind the STAR Program is that future science and math teachers can more effectively prepare the next generation of science, math, and engineering students if they themselves have authentic experiences as researchers.

  3. Comparison of the microbial dynamics and biochemistry of laboratory sourdoughs prepared with grape, apple and yogurt.

    PubMed

    Gordún, Elena; del Valle, Luis J; Ginovart, Marta; Carbó, Rosa

    2015-09-01

    The microbiological culture-dependent characterization and physicochemical characteristics of laboratory sourdough prepared with grape (GS) were evaluated and compared with apple (AS) and yogurt (YS), which are the usual Spanish sourdough ingredients. Ripe GS took longer than AS and YS to reach the appropriate acidity and achieved lower values of lactic acid. In all sourdoughs, the lactic acid bacteria (LAB) increased during processing and were the dominant microorganisms (>1E+8 CFU/g). GS, as well as AS, had high diversity of LAB species. In ripe YS, Pediococcus pentosaceus was the only species identified; in GS and AS, several Lactobacilli were also found, Lb. plantarum, Lb. brevis, and Lb. sakei; in addition, in GS Weisella cibaria also appeared. Regarding the yeast population, non-Saccharomyces yeasts from GS and AS showed a very high specific population (>1E+7 CFU/g), but this was reduced in ripe sourdough (<1E+4 CFU/g). Finally, the Saccharomyces group dominated in all sourdoughs. Starting ingredients or raw material provided microbiological specificity to sourdoughs, and grape could be considered one of them.

  4. Complexity of Reasoning about Children's Development: Links with Teacher-Preparation Content Courses and Supervised Laboratory Experience

    ERIC Educational Resources Information Center

    Guzell, Jacqueline R.; Stringer, Sharon A.

    2004-01-01

    In a sample of 74 university students studying early childhood and pre-kindergarten education, researchers assessed the relationships between child development knowledge, complexity of reasoning about development, prior work experience with children, and teacher-preparation content courses and laboratory courses. There was no statistically…

  5. A Guide for Planning Facilities for Occupational Preparation Programs for Dental Laboratory Technicians. Research Series No. 34.

    ERIC Educational Resources Information Center

    Macconnell, James D., And Others

    The twelfth in a series also including guides for facilities for medical x-ray technologist, medical assistant, and medical secretary programs, the document is intended for use in the preparation of educational specifications for facilities for dental laboratory technician programs. Designed for use by those responsible for planning facilities,…

  6. An algorithm for pre- and post-irradiation fade in the Thermo 8802 LiF:Mg,Ti thermoluminescent dosimeter.

    PubMed

    Hill, Carolyn D

    2005-05-01

    The diminished response of thermoluminescent phosphors over time is a well-documented challenge to thermoluminescent dosimetry. Wide ranges in fading rates for various phosphor types have been reported, making it necessary for many external dosimetry programs to perform individual studies on thermoluminescent fade. Sandia National Laboratories currently uses the Thermo 8802 LiF:Mg,Ti thermoluminescent dosimeter (TLD) in its personnel external dosimetry program. Doses received in the field are calculated by applying a fade algorithm published by the manufacturer to TLD readings. Since the algorithm was established by characterizing the diminished response of a TLD similar to the 8802, Sandia chose to model its fade study after the analysis done by Thermo. As a result, the parameters of each experiment were comparable, and data from the two studies were compared to determine whether or not the current algorithm should be modified specifically for use at Sandia. Cards were irradiated using an internal Sr/Y source, and pre- and post-irradiation fading rates were monitored over a period of 18 wk. While significant fading was demonstrated, results closely matched those found in the original Thermo study.

  7. The natural thermoluminescence of meteorites. VI - Carbon-14, thermoluminescence and the terrestrial ages of meteorites

    NASA Technical Reports Server (NTRS)

    Benoit, P. H.; Jull, A. J. T.; Mckeever, S. W. S.; Sears, D. W. G.

    1993-01-01

    A relationship is noted between the natural thermoluminescence (TL) levels and the C-14-derived terrestrial ages for meteorite finds from the U.S. Prairie States and Roosevelt County, NM; those in the Sahara are also in accord with calculated TL decay curves, for 'storage' temperatures equal to the approximate average annual temperatures at individual sites. This discussion is limited to the empirical correspondence between the two methodologies, and to theoretical decay curves for a single 'average' ordinary chondrite.

  8. 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.

  9. 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.

  10. Integration of Video-Based Demonstrations to Prepare Students for the Organic Chemistry Laboratory

    ERIC Educational Resources Information Center

    Nadelson, Louis S.; Scaggs, Jonathan; Sheffield, Colin; McDougal, Owen M.

    2015-01-01

    Consistent, high-quality introductions to organic chemistry laboratory techniques effectively and efficiently support student learning in the organic chemistry laboratory. In this work, we developed and deployed a series of instructional videos to communicate core laboratory techniques and concepts. Using a quasi-experimental design, we tested the…

  11. Environmental dosimeter of the thermoluminescent type

    DOEpatents

    Eichner, F.N.; Kocher, L.F.

    1974-01-29

    A dosimeter for accurately monitoring normally low-energy radiation including a thermoluminescent CaF phosphor enclosed within a tantalum capsule is described. The tantalum acts as a filter to weaken the measured dose due to photons having energies below about 0.2 MeV. Tantalum end caps are maintained on the capsule body by a polyolefin sheath formed from heat-contractable tubing. After exposing the dosimeter to environmental radiation, it is placed in a shielded chamber for about 24 h and subsequently annealed at about 80 deg C to release radiation energy accumulated in low-temperature traps. The dosimeter is then disassembled and the phosphors photometrically read at temperatures about 50 deg C to determine the absorbed radiation dose. (Official Gazette)

  12. Thermoluminescence properties of sintered ZnO

    NASA Astrophysics Data System (ADS)

    Borbón-Nuñez, H. A.; Cruz-Vázquez, C.; Bernal, R.; Kitis, G.; Furetta, C.; Castaño, V. M.

    2014-11-01

    New pellet-shaped ZnO phosphors were synthesized using a controlled chemical reaction. Some samples were sintered at 1123, 1173 or 1223 K during 24 h in air, and then exposed to beta particle irradiation in the dose range from 25 to 800 Gy to investigate their thermoluminescence (TL) properties. By considering their sensitivity, reproducibility, and fading features, samples sintered at 1173 K exhibit the best dosimetric characteristics. From computerized glow curve deconvolution that was carried out using a general order equation, the kinetics parameters were computed, and it was found that the glow curves are composed by six individual TL peaks with kinetics order ranging from 1.2 to 1.8.

  13. Thermoluminescence properties of irradiated chickpea and corn

    NASA Astrophysics Data System (ADS)

    Necmeddin Yazici, A.; Bedir, Metin; Bozkurt, Halil; Bozkurt, Hüseyin

    2008-02-01

    A study was carried out to establish a detection method for irradiated chickpea and corn by thermoluminescence (TL) method. The leguminous were packed in polyethylene bags and then the packets were irradiated at room temperature at different doses by 60Co gamma source at 1, 4, 8 and 10 kGy. Minerals extracted from the leguminous were deposited onto a clean aluminum disc and TL intensities of the minerals were measured by TL. It was observed that the extracted samples from both leguminous exhibit good TL Intensity and the TL intensity of glow curves of them increased proportionally to irradiation doses. The TL glow curve of both irradiated leguminous presents a single broad peak below 400 °C. The TL trapping parameters glow peaks were estimated by the additive dose (AD), Tm(Ea)-Tstop and computerized glow curve deconvolution (CGCD) methods. The fading characteristics of glow curves were also recorded up to 6 months.

  14. The thermoluminescence carrier in the Dhajala chondrite

    NASA Technical Reports Server (NTRS)

    Sparks, M. H.; Mckimmey, P. M.; Sears, D. W. G.

    1983-01-01

    It is pointed out that the type 3 (unequilibrated) ordinary chondrites provide a major source of information on the early solar system. However, the interpretation of the data is difficult because all but a few display signs of metamorphic alteration. The present investigation is concerned with the thermoluminescence (TL) sensitivity measurements on 58 chondrules separated from the Dhajala meteorites. The data were discussed briefly by Sparks and Sears (1982). In the current investigation particular attention is given to the constraints placed by these data on the mechanism by which metamorphism is related to TL sensitivity. Dhajala-normalized TL sensitivity of the separated chondrules is plotted against chondrule mass, and a histogram of the CaO contents of 15 chondrules is presented. Histograms showing the TL sensitivity of chondrules separated from the Dhajala meteorite are also provided.

  15. Diamond thermoluminescence properties of different chondrites

    NASA Technical Reports Server (NTRS)

    Fisenko, A. V.; Kashkarov, L. L.; Semjonova, L. F.; Pillinger, C. T.

    1993-01-01

    It was found that thermoluminescence (TL) glows of diamonds depend on the origin of diamonds and the chondrite metamorphism degree. The investigation of TL of diamonds was continued and the results for diamonds from Murchison CM2, Krymka LL3.0, Kainsaz CO3, and Abee E4 were considered. The diamonds synthesized by CVD-process (samples 133, 159) and by detonation from soot (DDS-B14-89) were also analyzed for comparison. Before the TL measuring samples were annealed at approximately 350 C for a few seconds and then irradiated by gamma-rays of Cs-137 up to dose approximately 200 krad. TL-measurements were performed in the air atmosphere on the standard equipment. TL data for samples are shown. TL glow for some diamonds are also presented.

  16. Interpretation of thermoluminescence patterns around a Wyoming roll-type uranium deposit

    USGS Publications Warehouse

    Spirakis, Charles S.

    1979-01-01

    Thermoluminescence from quartz and feldspar grains in samples collected from the vicinity of a Wyoming roll-type uranium deposit show an increase in the importance of high-temperature thermoluminescence relative to low-temperature thermoluminescence of samples which are believed to be former positions of the migrating mineralized front. This effect is believed to be due to the increased radiation in the ore coupled with the faster rate of fading of low-temperature thermoluminescence compared to high-temperature thermoluminescence. Both the ratios of thermoluminescent responses from any of a variety of temperature ranges and glow curves (plots of intensity of thermoluminescence versus temperature) can be used to detect the increased importance of high-temperature thermoluminescence relative to low-temperature thermoluminescence of previously mineralized samples. Both ratios and glow curves present a systematic pattern around this deposit; these patterns may have application in uranium prospecting.

  17. Thermoluminescence characterization of the irradiated minerals extracted from nopal

    NASA Astrophysics Data System (ADS)

    Cruz-Zaragoza, E.; Furetta, C.; Kitis, G.; Gomez, B. T.; Polymeris, G. S.; Tsirliganis, N.; Loukou, Z.

    2006-05-01

    The mineral fraction from dehydrated nopal leaves (Opuntia ficus indica ) belonging to the Cactaceae family was extracted and selected by sizes of 10 and 74 mu m and exposed to 60 Co gamma radiation at different doses in the range 70 Gy-20 kGy. The glow-curves from these polyminerals show a thermoluminescence (TL) band with one very intense peak at a temperature around 150 degrees C and a second one emerging in the high temperature region, moving in a large zone of temperature values according to the preparation used and the level of irradiation. The XRD analysis shows a composition of both biominerals as whewellite and weddellite and a mineral fraction as anorthoclase and quartz. The main TL characteristics of the polymineral content of the nopal was analyzed, i.e . the TL response at different doses and fading during storage at room temperature. The activation energy of the traps responsible for the TL emission was also investigated and a possible continuous distribution of traps is discussed. A review of the scientific literature shows that this is the first time that a TL study on nopal ionized by irradiation has been carried out.

  18. Comparative analysis of the scintillation and thermoluminescent properties of Ce-doped LSO and YSO crystals and films

    NASA Astrophysics Data System (ADS)

    Zorenko, Yu.; Gorbenko, V.; Bilski, P.; Twardak, A.; Mandowska, E.; Mandowski, A.; Sidletskiy, O.

    2014-08-01

    The work is devoted to the comparative analysis of the scintillation and thermoluminescent properties of the undoped and Ce-doped A2SiO5 (A = Lu, Y) orthosilicates, prepared in single crystal form by the Czochralski method and in the form of single crystalline film using the liquid phase epitaxy method. We have found that differences in the methods of material preparation resulted in the significant differences in the scintillation and thermoluminescent properties of undoped and Ce doped YSO and LSO crystals and films. Such differences are caused by the presence or absence of main host defects (first of all, oxygen vacancies and flux related impurities) as emission and trapping centers in YSO and LSO crystals and films.

  19. An Integrated Laboratory Approach toward the Preparation of Conductive Poly(phenylene vinylene) Polymers

    ERIC Educational Resources Information Center

    Knoerzer, Timm A.; Balaich, Gary J.; Miller, Hannah A.; Iacono, Scott T.

    2014-01-01

    Poly(phenylene vinylene) (PPV) represents an important class of conjugated, conducting polymers that have been readily exploited in the preparation of organic electronic materials. In this experiment, students prepare a PPV polymer via a facile multistep synthetic sequence with robust spectroscopic evaluation of synthetic intermediates and the…

  20. Identification by genotyping of a commercial antigen preparation as the source of a laboratory contamination with Coxiella burnetii and as an unexpected rich source of control DNA.

    PubMed

    Tilburg, Jeroen J H C; Horrevorts, Alphons M; Peeters, Marcel F; Klaassen, Corné H W; Rossen, John W A

    2011-01-01

    By performing genotyping, a laboratory contamination involving Q fever was traced back to the antigen preparation used in a commercially available complement fixation test. It was established that such antigen preparations contain relatively high loads of DNA/RNA, making them potential sources of contamination but also convenient preparations for control material.

  1. Preparing the Biochemistry Laboratory for the Next Outbreak: Lessons from SARS in Singapore

    PubMed Central

    2005-01-01

    Severe acute respiratory syndrome (SARS) is an emerging disease characterised by fever and atypical pneumonia and caused by a novel coronavirus. Singapore was affected by the global pandemic in early 2003, with 238 cases and 33 deaths. Samples sent to the biochemistry laboratory made up the majority (69%) of all SARS samples, yet remained a minority (29%) of total biochemistry workload. This paper describes the problems encountered and solutions adopted by the biochemistry laboratory at the designated SARS hospital in coping with this epidemic. It provides practical advice for laboratories planning for the handling of samples from future outbreaks. PMID:16450013

  2. Thermoluminescence of shock-loaded amethyst quartz

    NASA Astrophysics Data System (ADS)

    Plath, I.; Lehmann, G.

    1987-05-01

    In natural amethyst samples subjected to shock pressures between 10 and 50 GPa (1 GPa=109 Pa), thermoluminescence (TL) was observed after subsequent X-ray irradiation, in some cases even without high energy irradiation. The glow curves could be decomposed into at most five components of Gaussian shape, but no reliable activation energies could be determined from them, perhaps due to a wide distribution of trap depths. With increasing shock pressures traps of higher thermal stability were favored. Emission bands with maxima near 14000 cm-1 were observed independent of shock pressure. They appear to be characteristic of defects created during the shock events, but it is uncertain whether the observed TL is connected with the iron impurities characteristic for amethyst. In natural amethyst samples of the same origin no TL could be observed, even after additional X-ray irradiation. It is concluded that TL in amethysts reported in the literature was actually caused by defects associated with aluminium impurities, not by destruction of Fe4+.

  3. The influence of the cavity preparation design on marginal accuracy of laboratory-processed resin composite restorations.

    PubMed

    Fonseca, Rodrigo Borges; Correr-Sobrinho, Lourenço; Fernandes-Neto, Alfredo Júlio; Quagliatto, Paulo Sérgio; Soares, Carlos José

    2008-03-01

    The aim of this study was to evaluate the influence of different cavity preparation designs on marginal accuracy of laboratory-processed resin composite restored teeth. Eighty mandibular human third molars were selected. There were two experimental factors, occlusal isthmus width (narrow vs wide) and cuspal coverage (inlay, one-cusp onlay, two-cusp onlay, and all-cusp onlay), resulting on eight groups (N = 10). Indirect composite restorations (SR Adoro, Ivoclar-Vivadent) were manufactured and positioned over each respective preparation. Marginal accuracy evaluation was accomplished using a stereomicroscope at three points on buccal, lingual, mesial, and distal regions with 40x magnification. The results showed significant differences (P = 0.00) with wide inlay showing the best overall marginal accuracy and narrow inlay the worst one. Two-way analysis of variance (ANOVA) showed significant differences when considering the factor occlusal isthmus width (P = 0.00). In general, preparations with wide occlusal isthmus presented better results than narrow ones, except for wide all-cusp onlays; however, the test failed to show differences when considering the cuspal coverage (P = 0.42) or the interaction between both factors (P = 0.30). The effect of occlusal width extension on marginal accuracy of indirect composite resin restorations is significant, with lower values of gaps width in wide preparations, but since in a clinical situation this would mean greater removal of sound tooth structure, less-aggressive preparations combined with other restorative procedures seem to be more feasible.

  4. Apparatuses and methods for laser reading of thermoluminescent phosphors

    DOEpatents

    Braunlich, Peter F.; Tetzlaff, Wolfgang

    1989-01-01

    Apparatuses and methods for rapidly reading thermoluminescent phosphors to determine the amount of luminescent energy stored therein. The stored luminescent energy is interpreted as a measure of the total exposure of the thermoluminescent phosphor to ionizing radiation. The thermoluminescent phosphor reading apparatus uses a laser to generate a laser beam. The laser beam power level is monitored by a laser power detector and controlled to maintain the power level at a desired value or values which can vary with time. A shutter or other laser beam interrupting means is used to control exposure of the thermoluminescent phosphor to the laser beam. The laser beam can be equalized using an opitcal equalizer so that the laser beam has an approximately uniform power density across the beam. The heated thermoluminescent phosphor emits a visible or otherwise detectable luminescent emission which is measured as an indication of the radiation exposure of the thermoluminscent phosphors. Also disclosed are preferred signal processing and control circuits including one system using a digital computer. Also disclosed are time-profiled laser power cycles for pre-anneal, read and post-anneal treatment of phosphors.

  5. Modified ferrous ammonium sulfate benzoic acid xyelenol orange (MFBX) and thermoluminescent dosimeters--a comparative study.

    PubMed

    Brindha, S; Rose, J V R; Sathyan, S; Singh I, Rabi Raja; Ravindran, B Paul

    2002-06-07

    Radiation dosimetry deals with the determination of absorbed dose to the medium exposed to ionizing radiation. Chemical dosimetry depends on oxidation or reduction of chemicals by ionizing radiation. A ferrous ammonium sulfate benzoic acid xyelenol orange (FBX) dosimeter based on this principle is being used as a clinical dosimeter at present. Certain modifications were carried out in the preparation and storage of the FBX dosimeter to increase its shelf life. The resulting dosimeter was called a modified FBX (MFBX) dosimeter and has been used in our department for the past few years. An extensive study of the dose, dose rate and energy response of the dosimeter was carried out and compared with a thermoluminescent (LiF7) dosimeter. The results obtained were found to be comparable to the thermoluminescent (LiF7) dosimeter. Hence it was concluded that the MFBX dosimeter could be used for phantom dosimetry, data collection and in vivo measurements. Easier preparation and availability of the reagents are added advantages of using MFBX as a clinical dosimeter in small radiotherapy departments.

  6. Thermoluminescent response of C-modified Al2O3 thin films deposited by parallel laser ablation plasmas

    NASA Astrophysics Data System (ADS)

    Garcés, J.; Escobar-Alarcón, L.; Gonzalez-Martinez, P. R.; Solís-Casados, D. A.; Romero, S.; Gonzalez-ZAvala, F.; Haro-Poniatowski, E.

    2017-01-01

    Aluminium oxide thin films modified with different amounts of carbon were prepared using a parallel laser ablation plasmas configuration. The effect of the amount of carbon incorporated in the films on their compositional, morphological, structural, and thermoluminescent properties was studied. The results showed that films with different C content, from 11 to 33 at. %, were obtained. The structural characterization revealed the growth of an amorphous material. Surface morphology of the obtained thin films showed smooth surfaces. The films were exposed to UV and gamma radiation (Co-60) in order to study their thermoluminescence response. The results tend to indicate that carbon incorporation into the alumina favours the increase of a high temperature TL peak.

  7. Clinical Chemistry Laboratory Automation in the 21st Century - Amat Victoria curam (Victory loves careful preparation).

    PubMed

    Armbruster, David A; Overcash, David R; Reyes, Jaime

    2014-08-01

    The era of automation arrived with the introduction of the AutoAnalyzer using continuous flow analysis and the Robot Chemist that automated the traditional manual analytical steps. Successive generations of stand-alone analysers increased analytical speed, offered the ability to test high volumes of patient specimens, and provided large assay menus. A dichotomy developed, with a group of analysers devoted to performing routine clinical chemistry tests and another group dedicated to performing immunoassays using a variety of methodologies. Development of integrated systems greatly improved the analytical phase of clinical laboratory testing and further automation was developed for pre-analytical procedures, such as sample identification, sorting, and centrifugation, and post-analytical procedures, such as specimen storage and archiving. All phases of testing were ultimately combined in total laboratory automation (TLA) through which all modules involved are physically linked by some kind of track system, moving samples through the process from beginning-to-end. A newer and very powerful, analytical methodology is liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). LC-MS/MS has been automated but a future automation challenge will be to incorporate LC-MS/MS into TLA configurations. Another important facet of automation is informatics, including middleware, which interfaces the analyser software to a laboratory information systems (LIS) and/or hospital information systems (HIS). This software includes control of the overall operation of a TLA configuration and combines analytical results with patient demographic information to provide additional clinically useful information. This review describes automation relevant to clinical chemistry, but it must be recognised that automation applies to other specialties in the laboratory, e.g. haematology, urinalysis, microbiology. It is a given that automation will continue to evolve in the clinical laboratory

  8. Clinical Chemistry Laboratory Automation in the 21st Century - Amat Victoria curam (Victory loves careful preparation)

    PubMed Central

    Armbruster, David A; Overcash, David R; Reyes, Jaime

    2014-01-01

    The era of automation arrived with the introduction of the AutoAnalyzer using continuous flow analysis and the Robot Chemist that automated the traditional manual analytical steps. Successive generations of stand-alone analysers increased analytical speed, offered the ability to test high volumes of patient specimens, and provided large assay menus. A dichotomy developed, with a group of analysers devoted to performing routine clinical chemistry tests and another group dedicated to performing immunoassays using a variety of methodologies. Development of integrated systems greatly improved the analytical phase of clinical laboratory testing and further automation was developed for pre-analytical procedures, such as sample identification, sorting, and centrifugation, and post-analytical procedures, such as specimen storage and archiving. All phases of testing were ultimately combined in total laboratory automation (TLA) through which all modules involved are physically linked by some kind of track system, moving samples through the process from beginning-to-end. A newer and very powerful, analytical methodology is liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). LC-MS/MS has been automated but a future automation challenge will be to incorporate LC-MS/MS into TLA configurations. Another important facet of automation is informatics, including middleware, which interfaces the analyser software to a laboratory information systems (LIS) and/or hospital information systems (HIS). This software includes control of the overall operation of a TLA configuration and combines analytical results with patient demographic information to provide additional clinically useful information. This review describes automation relevant to clinical chemistry, but it must be recognised that automation applies to other specialties in the laboratory, e.g. haematology, urinalysis, microbiology. It is a given that automation will continue to evolve in the clinical laboratory

  9. Analytical Chemistry Laboratory (ACL) procedure compendium. Volume 2, Sample preparation methods

    SciTech Connect

    Not Available

    1993-08-01

    This volume contains the interim change notice for sample preparation methods. Covered are: acid digestion for metals analysis, fusion of Hanford tank waste solids, water leach of sludges/soils/other solids, extraction procedure toxicity (simulate leach in landfill), sample preparation for gamma spectroscopy, acid digestion for radiochemical analysis, leach preparation of solids for free cyanide analysis, aqueous leach of solids for anion analysis, microwave digestion of glasses and slurries for ICP/MS, toxicity characteristic leaching extraction for inorganics, leach/dissolution of activated metal for radiochemical analysis, extraction of single-shell tank (SST) samples for semi-VOC analysis, preparation and cleanup of hydrocarbon- containing samples for VOC and semi-VOC analysis, receiving of waste tank samples in onsite transfer cask, receipt and inspection of SST samples, receipt and extrusion of core samples at 325A shielded facility, cleaning and shipping of waste tank samplers, homogenization of solutions/slurries/sludges, and test sample preparation for bioassay quality control program.

  10. Thermoluminescence of β-Irradiated ZnS-ZnO Phosphors

    NASA Astrophysics Data System (ADS)

    Cruz-Vázquez, C.; Bernal, R.; Burruel-Ibarra, S. E.; Cota-Valenzuela, E.; Brown, F.; Grijalva-Monteverde, H.; Castaño, V. M.

    2015-10-01

    ZnS-ZnO thermoluminescent phosphors have been synthesized by a low-cost chemical method. They exhibit a thermoluminescence response increasing linearly as a function of β-irradiation dose, from 25 Gy to 1600 Gy, without saturation. The glow curves indicate that these phosphors could be useful for both thermoluminescence and afterglow dosimetry.

  11. A Laboratory Preparation of Aspartame Analogs Using Simultaneous Multiple Parallel Synthesis Methodology

    ERIC Educational Resources Information Center

    Qvit, Nir; Barda, Yaniv; Gilon, Chaim; Shalev, Deborah E.

    2007-01-01

    This laboratory experiment provides a unique opportunity for students to synthesize three analogues of aspartame, a commonly used artificial sweetener. The students are introduced to the powerful and useful method of parallel synthesis while synthesizing three dipeptides in parallel using solid-phase peptide synthesis (SPPS) and simultaneous…

  12. Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

    DOEpatents

    Braunlich, P.F.; Tetzlaff, W.

    1989-04-25

    Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters are disclosed. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phosphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate. 34 figs.

  13. Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

    DOEpatents

    Braunlich, Peter F.; Tetzlaff, Wolfgang

    1989-01-01

    Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phoshphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate.

  14. Preparation and Analysis of Libethenite: A Project for the First-Year Laboratory

    ERIC Educational Resources Information Center

    Ginion, Kelly E.; Yoder, Claude H.

    2004-01-01

    The preparation of libethenite, a double salt of copper(II) phosphate and copper(II) hydroxide presents the opportunity to discuss the prevalence of double salts in the environment, the relationship between solubility and stability in aqueous solution, the origin of the color of transition metal compounds and gravimetric analyses. Typical results…

  15. Sedimentation Coefficient, Frictional Coefficient, and Molecular Weight: A Preparative Ultracentrifuge Experiment for the Advanced Undergraduate Laboratory.

    ERIC Educational Resources Information Center

    Halsall, H. B.; Wermeling, J. R.

    1982-01-01

    Describes an experiment using a high-speed preparative centrifuge and calculator to demonstrate effects of the frictional coefficient of a macromolecule on its rate of transport in a force field and to estimate molecular weight of the macromolecule using an empirical relationship. Background information, procedures, and discussion of results are…

  16. Preparation of Semiconducting Materials in the Laboratory, Part 3: The One-Penny Photovoltaic Cell

    ERIC Educational Resources Information Center

    Ibanez, Jorge G.; Finck-Pastrana, Adolfo; Mugica-Barrera, Alejandra; Balderas-Hernandez, Patricia; Ibarguengoitia-Cervantes, Martha E.; Garcia-Pintor, Elizabeth; Hartasanchez-Frenk, Jose Miguel; Bonilla-Jaurez, Cesar E.; Maldonado-Cordero, Casandra; Struck-Garza, Adelwart; Suberbie-Rocha, Felipe

    2011-01-01

    Copper(I) oxide photoresponsive layers are prepared on copper surfaces (e.g., U.S. pre-1982 pennies) by simple thermal, chemical, and electrochemical procedures. An easily measurable photovoltage (up to 100 mV) is obtained in each case under visible light illumination. (Contains 2 figures.)

  17. Laboratory Studies of Lead Removal from Liquid Scintillator in Preparation for KamLAND's Low Background Phase

    SciTech Connect

    Keefer, Gregory

    2011-04-27

    The removal of Radon induced Lead from liquid scintillator was extensively studied in preparation for KamLAND's low background phase. This work presents the results from laboratory experiments performed at the University of Alabama and their implications for KamLAND and future low background experiments using carbon based liquid scintillator. It was observed that distillation was the most effective purification procedure and that one must consider a non-polar and non-ionic component of Lead in order to reach the levels of radio-purity required for these new class of ultra-low background experiments.

  18. Quality control program for the Hanford External Dosimetry thermoluminescent processing system

    SciTech Connect

    Baumgartner, W.V.; Endres, A.W.; Reese, S.R.

    1992-09-01

    The Hanford External Dosimetry Program is operated by Pacific Northwest Laboratory for the US Department of Energy (DOE). The program records official external occupational radiation doses for all Hanford Site employees and visitors in compliance with DOE Order requirements. This report documents the quality control (QC) program for External Dosimetry's thermoluminescent dosimeter (TLD) processing system. The focus of the External Dosimetry Program has been (1) to accurately calculate personnel radiation doses, and (2) to document the methods used to report doses in order, to meet DOE Laboratory Accreditation Program (DOELAP) criteria. The purpose of this report is to describe the QC procedures used for dosimeters and processing equipment. Use of QC procedures allows for the prompt correction of unusual data before it is reported.

  19. Quality control program for the Hanford External Dosimetry thermoluminescent processing system

    SciTech Connect

    Baumgartner, W.V.; Endres, A.W.; Reese, S.R.

    1992-09-01

    The Hanford External Dosimetry Program is operated by Pacific Northwest Laboratory for the US Department of Energy (DOE). The program records official external occupational radiation doses for all Hanford Site employees and visitors in compliance with DOE Order requirements. This report documents the quality control (QC) program for External Dosimetry`s thermoluminescent dosimeter (TLD) processing system. The focus of the External Dosimetry Program has been (1) to accurately calculate personnel radiation doses, and (2) to document the methods used to report doses in order, to meet DOE Laboratory Accreditation Program (DOELAP) criteria. The purpose of this report is to describe the QC procedures used for dosimeters and processing equipment. Use of QC procedures allows for the prompt correction of unusual data before it is reported.

  20. Application of thermoluminescence technique to identify radiation processed foods

    NASA Astrophysics Data System (ADS)

    Kiyak, N.

    1995-02-01

    Research studies reported by various authors have shown that a few methods one of which is thermoluminescence technique- may be suitable for identification of some certain irradiated spicies and food containing bones. This study is an application of the thermoluminescence technique for identifying the irradiated samples. The investigation was carried out on different types of foodstuffs such as onions, potatoes and kiwi. Measurements show that the technique can be applied as a reliable method to distinguish the irradiated food products from non-irradiated ones. The results demonstrate also that it is possible to use this method for determining the absorbed dose of irradiated samples from the established dose-effect curve.

  1. Thermoluminescence and lattice defects in LiF

    NASA Technical Reports Server (NTRS)

    Stoebe, T. G.; Watanabe, S.

    1975-01-01

    The principal effect of thermal and optical treatments in an ionic solid is to alter the lattice defect equilibrium, including the concentration and arrangement of ion vacancies, impurities, impurity-vacancy associates, and assorted electrons and holes which may be associated with such defects. This paper examines the relationship between these defects and thermoluminescence in the case of lithium fluoride at and above room temperature. The discussion focuses on lattice defect equilibrium, thermoluminescent trapping centers, the relationship between recombination and luminescence, the supralinearity and sensitization of the dosimetry grade of LiF and activation energy parameters.

  2. PREPARATIONS FOR ASSEMBLY OF THE INTERNATIONAL ERL CRYOMODULE AT DARESBURY LABORATORY

    SciTech Connect

    McIntosh, P. A.; Bate, R.; Beard, C. D.; Cordwell, M. A.; Dykes, D. M.; Pattalwar, S. M.; Strachan, J.; Belomestnykh, S.; Liepe, M.; Padamsee, H.; Quigley, P.; Sears, J.; Shemelin, V.; Veshcherevich, V.; Proch, D.; Sekutowicz, J.; Buchner, A.; Gabriel, F.; Michel, P.; Corlett, J. N.; Li, D.; Lidia, S.; Kimura, T.; Smith, T. I.

    2009-04-29

    The collaborative development of an optimised cavity/cryomodule solution for application on ERL facilities has now progressed to final assembly and testing of the cavity string components and their subsequent cryomodule integration. This paper outlines the verification of the various cryomodule sub-components and details the processes utilised forfinal cavity string integration. The paper also describes the modifications needed to facilitate this new cryomodule installation and ultimate operation on the ALICE facility at Daresbury Laboratory.

  3. Simulated Waste for Leaching and Filtration Studies--Laboratory Preparation Procedure

    SciTech Connect

    Smith, Harry D.; Russell, Renee L.; Peterson, Reid A.

    2009-10-27

    This report discusses the simulant preparation procedure for producing multi-component simulants for leaching and filtration studies, including development and comparison activities in accordance with the test plan( ) prepared and approved in response to the Test Specification 24590-WTP-TSP-RT-06-006, Rev 0 (Smith 2006). A fundamental premise is that this approach would allow blending of the different components to simulate a wide variety of feeds to be treated in the Hanford Tank Waste Treatment and Immobilization Plant (WTP). For example, a given feed from the planned feed vector could be selected, and the appropriate components would then be blended to achieve a representation of that particular feed. Using the blending of component simulants allows the representation of a much broader spectrum of potential feeds to the Pretreatment Engineering Platform (PEP).

  4. The planning and establishment of a sample preparation laboratory for drug discovery

    PubMed Central

    Dufresne, Claude

    2000-01-01

    Nature has always been a productive source of new drugs. With the advent of high-throughput screening, it has now become possible to rapidly screen large sample collections. In addition to seeking greater diversity from natural product sources (micro-organisms, plants, etc.), fractionation of the crude extracts prior to screening is becoming a more important part of our efforts. As sample preparation protocols become more involved, automation can help to achieve and maintain a desired sample throughput. To address the needs of our screening program, two robotic systems were designed. The first system processes crude extracts all the way to 96-well plates, containing solutions suitable for screening in biological and biochemical assays. The system can dissolve crude extracts, fractionate them on solid-phase extraction cartridges, dry and weigh each fraction, re-dissolve them to a known concentration, and prepare mother plates. The second system replicates mother plates into a number of daughter plates. PMID:18924691

  5. Thermoluminescence and optical characteristics of ZrO2 powder as a TL dosimeter

    NASA Astrophysics Data System (ADS)

    Montalvo, T. R.; Tenorio, L. O.; Nieto, J. A.; Celis, A. C.; Ordonez, C. V.; Fonseca, R. S.

    2004-11-01

    A description of the preparation of zirconium oxide (ZrO2) polycrystalline powder by the sol-gel method is presented. To prepare ZrO2 powder to be used as a thermoluminescent (TL) phosphor in dosimetric application, it is necessary to analyze some structural properties before, such as it's crystallinity. In this work, the property was verified using X-ray diffraction. ZrO2 polycrystalline powder obtained was subjected to thermal treatment by heating up to 1000 degrees C. Both the absorption spectrum and the emission spectrum were also studied. The TL glow curve of ZrO2 powder exhibited a peak when it was exposed to a radiation field. Results of analyzing optical properties and the preliminary results of studying the TL in ZrO2, indicate that the latter is a good candidate to be used as a TL dosimeter in radiation ionizing and UV-radiation fields.

  6. Thermoluminescence and photoluminescence of cerium doped CaSO 4 nanosheets

    NASA Astrophysics Data System (ADS)

    Zahedifar, M.; Mehrabi, M.

    2010-12-01

    Thermoluminescence (TL) and photoluminescence (PL) characteristics of CaSO 4:Ce nanocrystalline prepared by hydrothermal method has been studied. Its TL glow curve contains three overlapping glow peaks at around 490, 505 and 521 K. Emission spectra band at 303 and 324 nm were observed for the orthorhombic phase of nanosheets. TL response of the prepared nanocrystalline to β and γ radiation was studied and the sensitivity of the nanosheets was found much more than that of analogous microcrystalline and is around 10 times higher than the well known high sensitive TL dosimeter LiF:Mg, Cu, P (GR-200) hot-pressed chips. TL kinetic parameters of this nanocrystalline are also presented.

  7. Thermoluminescence dating of archaeological artefacts from the Middle Neolithic, Bronze Age and the Roman Empire period.

    PubMed

    Berger, T; Hajek, M; Primerano, W; Vana, N

    2002-01-01

    Thermoluminescence (TL) dating was applied for artefacts found near the small village of Michelstetten, Lower Austria. Settlements in this region can be traced hack a long time and, according to archaeologists, the discovered artefacts may be as old as 6000 years. A modified sample preparation technique based on the fine-grain method was developed. This technique results in a higher reproducibility and reduces the overall preparation time. For some artefacts the new information of the TL dating leads to an unforeseen re-interpretation of the archaeological age. Furthermore, an iron furnace from the period of the Roman Empire could be dated. For the first time, it was possible to estimate correctly the point of time of the burn-down of an ancient wooden house via an analysis of the house's clay plaster. The fire took place in the sixth century; this was confirmed by dating ceramic artefacts.

  8. Thermoluminescence of kunzite: A study of kinetic processes and dosimetry characteristics

    NASA Astrophysics Data System (ADS)

    Ogundare, F. O.; Alatishe, M. A.; Chithambo, M. L.; Costin, G.

    2016-04-01

    Since the use of natural minerals for dating and dose reconstruction using luminescence techniques is well-established and always of interest, we present thermoluminescence characteristics of kunzite, a gem variety of spodumene. The chemical composition of the sample was determined using an Electron Probe MicroAnalyzer to be (Li0.996Na0.009Mn0.006)∑ = 1.016(Al0.981Cr0.003Fe2+0.001)∑ = 0.995[(Si1.993Al0.008)∑ = 2.000O6]. Thermoluminescence glow curves measured at 0.5 K/s after laboratory irradiation consist of three prominent peaks at 338 K (labelled as peak I), 454 K (peak II) and 681 K (peak III). The dose response of these three peaks is linear in the range 20-308 Gy studied. The position of each of the peaks is independent of dose, an archetypical feature of first order behaviour. However, detailed kinetic analyses showed that in fact, the peaks are not subject to first order kinetics. Each of the three peaks is affected by thermal quenching with an associated activation energy of thermal quenching estimated to be 0.70, 1.35 and 0.54 eV for peaks I, II and III respectively. In terms of dosimetry use, only peak III was found to be reliable for possible use in luminescence dating and dose reconstruction.

  9. Preparing the next generation of genomicists: a laboratory-style course in medical genomics.

    PubMed

    Linderman, Michael D; Bashir, Ali; Diaz, George A; Kasarskis, Andrew; Sanderson, Saskia C; Zinberg, Randi E; Mahajan, Milind; Shah, Hardik; Suckiel, Sabrina; Zweig, Micol; Schadt, Eric E

    2015-08-12

    The growing gap between the demand for genome sequencing and the supply of trained genomics professionals is creating an acute need to develop more effective genomics education. In response we developed "Practical Analysis of Your Personal Genome", a novel laboratory-style medical genomics course in which students have the opportunity to obtain and analyze their own whole genome. This report describes our motivations for and the content of a "practical" genomics course that incorporates personal genome sequencing and the lessons we learned during the first three iterations of this course.

  10. Thermoluminescence properties of lithium magnesium borate glasses system doped with dysprosium oxide.

    PubMed

    Mhareb, M H A; Hashim, S; Ghoshal, S K; Alajerami, Y S M; Saleh, M A; Razak, N A B; Azizan, S A B

    2015-12-01

    We report the impact of dysprosium (Dy(3+)) dopant and magnesium oxide (MgO) modifier on the thermoluminescent properties of lithium borate (LB) glass via two procedures. The thermoluminescence (TL) glow curves reveal a single prominent peak at 190 °C for 0.5 mol% of Dy(3+). An increase in MgO contents by 10 mol% enhances the TL intensity by a factor of 1.5 times without causing any shift in the maximum temperature. This enhancement is attributed to the occurrence of extra electron traps created via magnesium and the energy transfer to trivalent Dy(3+) ions. Good linearity in the range of 0.01-4 Gy with a linear correlation coefficient of 0.998, fading as low as 21% over a period of 3 months, excellent reproducibility without oven annealing and tissue equivalent effective atomic numbers ~8.71 are achieved. The trap parameters, including geometric factor (μg), activation energy (E) and frequency factor (s) associated with LMB:Dy are also determined. These favorable TL characteristics of prepared glasses may contribute towards the development of Li2O-MgO-B2O3 radiation dosimeters.

  11. Comparison of slurry mixing and dry milling in laboratory sample preparation for determination of ochratoxin A and deoxynivalenol in wheat.

    PubMed

    Lippolis, Vincenzo; Pascale, Michelangelo; Valenzano, Stefania; Visconti, Angelo

    2012-01-01

    The significance of laboratory sample preparation for the determination of two important mycotoxins, ochratoxin A (OTA) and deoxynivalenol (DON), in wheat was investigated by comparing water-slurry mixing and dry-milling procedures. The distribution of OTA and DON in 10 kg samples of naturally contaminated wheat was established by analyzing one hundred 100 g subsamples of each sample. A normal distribution and a good repeatability of DON measurements was observed for both water-slurry mixing (mean 2290 microg/kg, CV 4.6%, median 2290 microg/kg) and dry milling (mean 2310 microg/kg, CV 6.4%, median 2290 microg/kg) procedures. For OTA determinations, reliable results could be obtained only by slurry mixing sample preparation (mean 2.62 microg/kg, CV 4.0%, median 2.62 microg/kg), whereas dry-milling comminution resulted in an inhomogeneous distribution with a high variability (mean 0.83 microg/kg, CV 75.2%, median 0.60 microg/kg) and a positive skewness (2.12). Ad hoc experiments were performed on different size portions of the same sample (10 kg) to assess accuracy and precision of the comminution/homogenization procedures (slurry mixing and dry milling). Very good results were obtained for DON determination with both procedures in terms of accuracy (>98.7% of the "weighted value") and precision (CV <3%). For OTA determination good results were only obtained by slurry mixing (99.4% of the "weighted value," CV 10%), whereas dry milling provided results with low accuracy (43.2% of the "weighted value") and high variability (CV 110%). This study clearly demonstrated that sample preparation by slurry mixing is strictly necessary to obtain reliable laboratory samples for OTA determination in wheat to minimize misclassification of acceptable/rejectable lots, mainly within official control.

  12. Preparation and characterization of a laboratory scale selenomethionine-enriched bread. Selenium bioaccessibility.

    PubMed

    Sánchez-Martínez, María; Pérez-Corona, Teresa; Caímara, Carmen; Madrid, Yolanda

    2015-01-14

    This study focuses on the preparation at lab scale of selenomethionine-enriched white and wholemeal bread. Selenium was supplemented either by adding selenite directly to the dough or by using lab-made selenium-enriched yeast. The best results were obtained when using fresh selenium-enriched yeast. The optimum incubation time for selenomethionine-enriched yeast preparation, while keeping formation of selenium byproducts to a minimum, was 96 h. Selenium content measured by isotope dilution analysis (IDA)-ICP-MS in Se-white and Se-wholemeal bread was 1.28 ± 0.02 μg g–1 and 1.16 ± 0.02 μg g–1 (expressed as mean ± SE, 3 replicates), respectively. HPLC postcolumn IDA-ICP-MS measurements revealed that selenomethionine was the main Se species found in Se-enriched bread, which accounted for ca. 80% of total selenium. In vitro gastrointestinal digestion assay provided selenium bioaccessibility values of 100 ± 3% and 40 ± 1% for white and wholemeal Se-enriched bread, respectively, being selenomethionine the main bioaccessible Se species in white bread, while in wholemeal bread this compound was undetectable.

  13. Induced thermoluminescence study of experimentally shock-loaded oligoclase

    NASA Technical Reports Server (NTRS)

    Ivliev, A. I.; Kashkarov, L. L.; Badjukov, D. D.

    1993-01-01

    Artificially induced thermoluminescence (TL) in oligoclase samples which were shock-loaded up to 27 GPa was measured. The essential increase of the TL sensitivity in relation to the total gamma-ray irradiation dose was observed only in samples at the 27 GPa pressure. This result can be explained by the initiation of additional radiation damages in the shocked oligoclace crystal lattice.

  14. Metamorphism of eucrite meteorites studied quantitatively using induced thermoluminescence

    NASA Technical Reports Server (NTRS)

    Batchelor, J. David; Sears, Derek W. G.

    1991-01-01

    Induced thermoluminescence studies provide a new and quantitative means of determining relative metamorphic intensities for eucrite meteorites, the simplest and most ancient products of basaltic volcanism. Using this technique, it is shown that the eucrites constitute a continuous metamorphic series and not, as commonly assumed, two groups of metamorphosed and nonmetamorphosed meteorites. It is suggested that the method may have applications to other basalts.

  15. Spatial distribution read-out system for thermoluminescence sheets

    NASA Technical Reports Server (NTRS)

    Yamamoto, I.; Tomiyama, T.; Imaeda, K.; Ninagawa, K.; Wada, T.; Yamashita, Y.; Misaki, A.

    1985-01-01

    A spatial distribution read-out system of thermoluminescence (TL) sheets is developed. This system consists of high gain image intensifier, a CCD-TV camera, a video image processor and a host computer. This system has been applied to artificial TL sheets (BaSO4:Eu doped) for detecting high energy electromagnetic shower and heavy nuclei tracks.

  16. Topics in Chemical Instrumentation: Cl. Thermoluminescence, Part I: Principles.

    ERIC Educational Resources Information Center

    Manche, Emanuel P.

    1979-01-01

    Following a delineation of thermoluminescence from a historical perspective and a qualitative description of the process, a treatment of the kinetic process based on a simple model is presented. This treatment model is adequate for the purpose of identifying the essential requirements in instrument design. (BT)

  17. Issues to consider for preparing ferrets as research subjects in the laboratory.

    PubMed

    Ball, Roberta Scipioni

    2006-01-01

    The domestic or European ferret (Mustela putorius furo) has been domesticated for thousands of years. Ferrets have been used for hunting and fur production, as pets, and as models in biomedical research. Despite the relatively small numbers used in the laboratory, ferrets have some unique applications including study of human influenza and severe acute respiratory syndrome (SARS)-associated corona virus. They have served as models for peptic ulcer disease, carotenoid metabolism, cystic fibrosis, and drug emesis screening, among others. Most research ferrets are males, due to estrus-related health problems in females. They may be housed conventionally and are easy to care for when their biology and behavior are understood. Due to the small number of ferret suppliers, animals are often shipped long distances, requiring air transport and intermediate handlers. It is important to minimize shipment stress, especially with weanling and pregnant animals. Additional expertise is required for success with pregnant and whelping ferrets and for rearing of neonates. The animals have specific dietary requirements, and proper nutrition is key. Successful housing requires knowledge of ferret behaviors including social behavior, eating habits, a general inquisitive nature, and a species-typical need to burrow and hide. Regular handling is necessary to maintain well-being. A ferret health care program consists of physical examination, immunization, clinical pathology, and a working knowledge of common ferret diseases. Various research methodologies have been described, from basic procedures such as blood collection to major invasive survival surgery. Ferrets have a distinct niche in biomedical research and are hardy animals that thrive well in the laboratory.

  18. Preparing Los Alamos National Laboratory's Waste Management Program for the Future - 12175

    SciTech Connect

    Jones, Scotty W.; Dorries, Alison M.; Singledecker, Steven; Henckel, George

    2012-07-01

    The waste management program at Los Alamos National Laboratory (LANL) is undergoing significant transition to establish a lean highly functioning waste management program that will succeed the large environmental cleanup waste management program. In the coming years, the environmental cleanup activities will be mostly completed and the effort will change to long-term stewardship. What will remain in waste management is a smaller program focused on direct off-site shipping to cost-effectively enable the enduring mission of the laboratory in support of the national nuclear weapons program and fundamental science and research. It is essential that LANL implement a highly functioning efficient waste management program in support of the core missions of the national weapons program and fundamental science and research - and LANL is well on the way to that goal. As LANL continues the transition process, the following concepts have been validated: - Business drivers including the loss of onsite disposal access and completion of major environmental cleanup activities will drive large changes in waste management strategies and program. - A well conceived organizational structure; formal management systems; a customer service attitude; and enthusiastic managers are core to a successful waste management program. - During times of organizational transition, a project management approach to managing change in a complex work place with numerous complex deliverables is successful strategy. - Early and effective engagement with waste generators, especially Project Managers, is critical to successful waste planning. - A well-trained flexible waste management work force is vital. Training plans should include continuous training as a strategy. - A shared fate approach to managing institutional waste decisions, such as the LANL Waste Management Recharge Board is effective. - An efficient WM program benefits greatly from modern technology and innovation in managing waste data and

  19. Preparing Laboratory and Real-World EEG Data for Large-Scale Analysis: A Containerized Approach

    PubMed Central

    Bigdely-Shamlo, Nima; Makeig, Scott; Robbins, Kay A.

    2016-01-01

    Large-scale analysis of EEG and other physiological measures promises new insights into brain processes and more accurate and robust brain–computer interface models. However, the absence of standardized vocabularies for annotating events in a machine understandable manner, the welter of collection-specific data organizations, the difficulty in moving data across processing platforms, and the unavailability of agreed-upon standards for preprocessing have prevented large-scale analyses of EEG. Here we describe a “containerized” approach and freely available tools we have developed to facilitate the process of annotating, packaging, and preprocessing EEG data collections to enable data sharing, archiving, large-scale machine learning/data mining and (meta-)analysis. The EEG Study Schema (ESS) comprises three data “Levels,” each with its own XML-document schema and file/folder convention, plus a standardized (PREP) pipeline to move raw (Data Level 1) data to a basic preprocessed state (Data Level 2) suitable for application of a large class of EEG analysis methods. Researchers can ship a study as a single unit and operate on its data using a standardized interface. ESS does not require a central database and provides all the metadata data necessary to execute a wide variety of EEG processing pipelines. The primary focus of ESS is automated in-depth analysis and meta-analysis EEG studies. However, ESS can also encapsulate meta-information for the other modalities such as eye tracking, that are increasingly used in both laboratory and real-world neuroimaging. ESS schema and tools are freely available at www.eegstudy.org and a central catalog of over 850 GB of existing data in ESS format is available at studycatalog.org. These tools and resources are part of a larger effort to enable data sharing at sufficient scale for researchers to engage in truly large-scale EEG analysis and data mining (BigEEG.org). PMID:27014048

  20. Preparing Laboratory and Real-World EEG Data for Large-Scale Analysis: A Containerized Approach.

    PubMed

    Bigdely-Shamlo, Nima; Makeig, Scott; Robbins, Kay A

    2016-01-01

    Large-scale analysis of EEG and other physiological measures promises new insights into brain processes and more accurate and robust brain-computer interface models. However, the absence of standardized vocabularies for annotating events in a machine understandable manner, the welter of collection-specific data organizations, the difficulty in moving data across processing platforms, and the unavailability of agreed-upon standards for preprocessing have prevented large-scale analyses of EEG. Here we describe a "containerized" approach and freely available tools we have developed to facilitate the process of annotating, packaging, and preprocessing EEG data collections to enable data sharing, archiving, large-scale machine learning/data mining and (meta-)analysis. The EEG Study Schema (ESS) comprises three data "Levels," each with its own XML-document schema and file/folder convention, plus a standardized (PREP) pipeline to move raw (Data Level 1) data to a basic preprocessed state (Data Level 2) suitable for application of a large class of EEG analysis methods. Researchers can ship a study as a single unit and operate on its data using a standardized interface. ESS does not require a central database and provides all the metadata data necessary to execute a wide variety of EEG processing pipelines. The primary focus of ESS is automated in-depth analysis and meta-analysis EEG studies. However, ESS can also encapsulate meta-information for the other modalities such as eye tracking, that are increasingly used in both laboratory and real-world neuroimaging. ESS schema and tools are freely available at www.eegstudy.org and a central catalog of over 850 GB of existing data in ESS format is available at studycatalog.org. These tools and resources are part of a larger effort to enable data sharing at sufficient scale for researchers to engage in truly large-scale EEG analysis and data mining (BigEEG.org).

  1. Verification analysis of thermoluminescent albedo neutron dosimetry at MOX fuel facilities.

    PubMed

    Nakagawa, Takahiro; Takada, Chie; Tsujimura, Norio

    2011-07-01

    Radiation workers engaging in the fabrication of MOX fuels at the Japan Atomic Energy Agency-Nuclear Fuel Cycle Engineering Laboratories are exposed to neutrons. Accordingly, thermoluminescent albedo dosemeters (TLADs) are used for individual neutron dosimetry. Because dose estimation using TLADs is susceptible to variation of the neutron energy spectrum, the authors have provided TLADs incorporating solid-state nuclear tracks detectors (SSNTDs) to selected workers who are routinely exposed to neutrons and have continued analysis of the relationship between the SSNTD and the TLAD (T/R(f)) over the past 6 y from 2004 to 2009. Consequently, the T/R(f) value in each year was less than the data during 1991-1993, although the neutron spectra had not changed since then. This decrease of the T/R(f) implies that the ratio of operation time nearby gloveboxes and the total work time has decreased.

  2. Environmental thermoluminescent dosimetry measurements at the WIPP (Waste Isolation Pilot Plant) Site, 1976-1985

    SciTech Connect

    Thompson, D.J.

    1988-02-01

    In 1975, the US Energy Research and Development Administration began evaluating a site in southeastern New Mexico for the possible construction and operation of a Waste Isolation Pilot Plant. The purpose of the facility was to test and demonstrate the operations and technical principles of a permanent repository in bedded salt for ERDA-generated transuranic radioactive waste. An extensive preoperational environmental study program to document the region's meterorology, geology, hydrology, flora and fauna, existing air and water quality, and background radiation was undertaken by Sandia National Laboratories. The purpose of this document is to report the final results of environmental thermoluminescent dosimeter measurements performed from January 1976 through December 1985. The final results were obtained by reevaluating the quarterly raw data using a uniform analysis procedure. 6 refs., 4 figs., 2 tabs.

  3. Thermoluminescence and optically stimulated luminescence in various phases of doped Na2SO4

    NASA Astrophysics Data System (ADS)

    Gaikwad, S. U.; Patil, R. R.; Kulkarni, M. S.; Bhatt, B. C.; Moharil, S. V.

    2016-02-01

    The dependence of optically stimulated luminescence (OSL) and thermoluminescence (TL) response due to crystal phase in Cu and Cu,Mg-doped Na2SO4 was studied. Study shows that the slowly cooled samples which crystallize in phase V show good OSL sensitivity whereas the quenched samples of Na2SO4 which crystallize in phase III irrespective of doping show no OSL sensitivity. However, during storage when phase III samples get converted to phase V, samples show OSL sensitivity comparable to freshly prepared samples in phase V. Hence, it is observed that TL-OSL properties of doped Na2SO4 are phase dependent .This study will be helpful in developing OSL phosphors in which phase plays an important role in deciding the desired properties.

  4. Investigation of thermoluminescence properties of mobile phone screen displays as dosimeters for accidental dosimetry

    NASA Astrophysics Data System (ADS)

    Mrozik, Anna; Marczewska, B.; Bilski, P.; Kłosowski, M.

    2014-11-01

    The rapid assessment of the radiation dose after unexpected exposure is a task of accidental dosimetry. In case of a radiological accident glasses originating from mobile phone screens, placed usually near the human body, could be used as emergency thermoluminescent (TL) personal dosimeters. The time between irradiation and TL readout is crucial and therefore preparation of the mobile phone screens and their readout conditions should be optimized. The influence of the samples etching, bleaching and selection of the optical filters based on measurement of the emission spectrum of irradiated glass samples during heating for different types of mobile phones were the subjects of our investigation. Obtained results showed that glasses extracted from different brands of mobile phones have different dosimetric properties but all of them give a luminescent signal which can be used to calculate the dose.

  5. Effect of adsorbed iron on thermoluminescence and electron spin resonance spectra of Ca-Fe-exchanged montmorillonite

    NASA Technical Reports Server (NTRS)

    Coyne, Lelia M.; Banin, Amos

    1986-01-01

    The ESR spectra and the natural and gamma-induced thermoluminescence (TL) glow curves of a series of variably cation-exchanged Fe-Ca-clays prepared from SWy-1 montmorillonite were examined. The ESR signal intensity associated with surface Fe increased linearly with surface Fe content up to a nominal concentration of 50 percent exchangeable Fe. At above 50 percent exchangeable Fe, no appreciable increase in the signal was noted. The TL intensity decreased linearly with increasing surface Fe up to 50 percent nominal exchangeable Fe. At above 50 percent, the signal was not appreciably further diminished. Possible effects of Fe on quenching of TL are considered.

  6. Experimental evaluation of PCXMC and prepare codes used in conventional radiology.

    PubMed

    Khelassi-Toutaoui, N; Berkani, Y; Tsapaki, V; Toutaoui, A E K; Merad, A; Frahi-Amroun, A; Brahimi, Z

    2008-01-01

    The objective of this study is to evaluate the precision of dose-calculation computer codes used in our laboratory (PCXMC and PREPARE) for organ dose evaluation. Measurements of entrance and organ dose were performed using ionisation chamber and thermoluminescence dosimetry. To obtain a mean dose of organ, we have used the Rando-Alderson phantom. The results showed that computed and measured doses correlate well (within 28%) in 60% of the samples. The percentage shows that the computed doses correlate with the experimental doses rather well for PCXMC software than PREPARE. Although the two programs are based on the Monte-Carlo method, their calculations differ. PCXMC carries out a simulation of the trajectory of the photon, whereas PREPARE provides interpolated values. Our experimental results are close to the values given by the PCXMC, a program which takes into account the weight, the height of the patient and field dimensions.

  7. Thermoluminescent properties of ZnS:Mn nanocrystalline powders.

    PubMed

    Ortiz-Hernández, Arturo Agustín; Méndez García, Víctor Hugo; Pérez Arrieta, María Leticia; Ortega Sígala, José Juan; Araiza Ibarra, José de Jesús; Vega-Carrillo, Héctor Rene; Falcony Guajardo, Ciro

    2015-05-01

    Thermoluminescent ZnS nanocrystals doped with Mn(2+) ions were synthesized by chemical co-precipitation method. From X-ray diffraction studies it was observed that the synthesized nanoparticles have cubic zinc blende structure with average sizes of about 40-50nm. Morphology was analyzed by TEM. Photoluminescence studies showed two transitions, one of them close to 396nm and other close to 598nm, which is enhanced with increasing dopant concentration, this behavior was also observed in the cathodoluminescence spectrum. The thermoluminescence gamma dose-response has linear behavior over dose range 5-100mGy, the glow curve structure shows two glow peaks at 436K and at 518K that were taken into account to calculate the kinetic parameters using the Computerized Glow Curve Deconvolution procedure.

  8. Thermoluminescence properties of gamma-irradiated nano-structure hydroxyapatite.

    PubMed

    Shafaei, M; Ziaie, F; Sardari, D; Larijani, M M

    2016-02-01

    The suitability of nano-structured hydroxyapatite (HAP) for use as a thermoluminescence dosimeter was investigated. HAP samples were synthesized using a hydrolysis method. The formation of nanoparticles was confirmed by X-ray diffraction and average particle size was estimated to be ~30 nm. The glow curve exhibited a peak centered at around 200 °C. The additive dose method was applied and this showed that the thermoluminescence (TL) glow curves follow first-order kinetics due to the non-shifting nature of Tm after different doses. The numbers of overlapping peaks and related kinetic parameters were identified from Tm -Tstop through computerized glow curve deconvolution methods. The dependence of the TL responses on radiation dose was studied and a linear dose response up to 1000 Gy was observed for the samples.

  9. Neutron Fading Characteristics of Copper Doped Lithium Fluoride (LiF: MCP) Thermoluminescent Dosimeters (TLDs)

    DTIC Science & Technology

    2008-05-21

    Fading Characteristics of Copper-Doped Lithium Fluoride (LiF: MCP) Thermoluminescent Dosimeters (TLDs)" Name of Candidate: L T Jeffrey A. Delzer Master...Lithium Fluoride Thermoluminescent Dosimeters beyond brief excerpts is with the permission of the copyright owner, and will save and hold harmless...Thesis: Author: Thesis directed by: ABSTRACT "Neutron Fading Characteristics of Copper-Doped Lithium Fluoride (LiF: MCP) Thermoluminescent

  10. Cathodoluminescence and Thermoluminescence of Undoped LTB and LTB:A (A = Cu, Ag, Mn)

    DTIC Science & Technology

    2013-03-01

    CATHODOLUMINESCENCE AND THERMOLUMINESCENCE OF UNDOPED LTB AND LTB:A (A = Cu, Ag, Mn) THESIS Zachary L. Hadfield, USA AFIT-ENP-13-M-13...CATHODOLUMINESCENCE AND THERMOLUMINESCENCE OF UNDOPED LTB AND LTB:A (A = Cu, Ag, Mn) THESIS Presented to the Faculty Department of Engineering...crystals and one each doped with silver, copper, and manganese. Thermoluminescence measurements were conducted using a Harshaw Model 3500 Manual TLD

  11. Methods and means of checking thermoluminescent and radiophotoluminescent dosimeters

    SciTech Connect

    Fominykh, V.I.; Oborin, A.V.; Sebekin, A.P.; Uryaev, I.A.

    1987-06-01

    The authors discuss methods of checking thermoluminescent and radiophotoluminescent dosimeters which are used often in monitoring radiation safety in various areas including nuclear power stations. When the dosimeters are checked in the fields of standard beta-ray sources, it is recommended that the standard absorbed-dose or equivalent-dose measures for beta radiation should be sources of /sup 90/Sr + /sup 90/Y, /sup 204/Tl, and /sup 147/Pm. Various safety guidelines are discussed.

  12. Thermoluminescence and dielectric response of gamma irradiated muscovite mica

    SciTech Connect

    Kaur, Sukhnandan Singh, Surinder Singh, Lakhwant; Lochab, S. P.

    2014-04-24

    The effect of gamma radiation dose on the thermoluminescence (TL) and dielectric properties of muscovite mica was studied. TL glow curves exhibited a single peak around 141 {sup 0}C and its activation energy was estimated to be about 0.89 eV. Different dielectric parameters like dielectric constant, dielectric loss and ac conductivity have been calculated in both pristine and gamma irradiated samples. These dielectric parameters have been studied as a function of irradiation dose.

  13. Thermoluminescence and dielectric response of gamma irradiated muscovite mica

    NASA Astrophysics Data System (ADS)

    Kaur, Sukhnandan; Singh, Surinder; Singh, Lakhwant; Lochab, S. P.

    2014-04-01

    The effect of gamma radiation dose on the thermoluminescence (TL) and dielectric properties of muscovite mica was studied. TL glow curves exhibited a single peak around 141 0C and its activation energy was estimated to be about 0.89 eV. Different dielectric parameters like dielectric constant, dielectric loss and ac conductivity have been calculated in both pristine and gamma irradiated samples. These dielectric parameters have been studied as a function of irradiation dose.

  14. Thermoluminescence kinetics of pyrite (FeS sub 2 )

    SciTech Connect

    Silverman, A.N; Levy, P.W.; Kierstead, J.A.

    1990-01-01

    Thermoluminescence of pyrite (FeS{sub 2}) has been investigated to study the kinetics of single peak glow curves. The material used normally exhibits one large and four small peaks. However a glow curve can be obtained with only the large single peak that is suitable for testing thermoluminescence kinetics. Glow curves from aliquots of a single natural pyrite crystal studied in detail contain two low intensity thermoluminescence (TL) peaks at {approx}90{degree} and {approx}250{degree}C, and two chemiluminescence (CL) peaks at {approx}350{degree} and {approx}430{degree}C. The CL peaks are largely removable by initially heating the sample chamber under vacuum, pumping through liquid nitrogen traps, and recording glow curves immediately after helium is introduced, procedures which reduce system contaminants that react with pyrite. The shape, the variation of the temperature of the peak maximum (T{sub max}) with dose, and the retrapping to recombination cross section ratio {sigma} of the large 250{degree}C peak are better described by the general one trap (GOT) kinetic equation, the basic equation from which the 1st and 2nd order kinetic equations are obtained as special cases (see text), than by the 1st and 2nd order equations. 12 refs., 7 figs.

  15. Thin thermoluminescent dosimeter and method of making same

    DOEpatents

    Simons, Gale G.; DeBey, Timothy M.

    1987-01-01

    An improved thermoluminescent ionizing radiation dosimeter of solid, extremely thin construction for more accurate low energy beta dosimetry is provided, along with a method of fabricating the dosimeter. In preferred forms, the dosimeter is a composite including a backing support (which may be tissue equivalent) and a self-sustaining body of solid thermoluminescent material such as LiF having a thickness of less than about 0.25 millimeters and a volume of at least about 0.0125 mm.sup.3. In preferred fabrication procedures, an initially thick (e.g., 0.89 millimeters) TLD body is wet sanded using 600 grit or less sandpaper to a thickness of less than about 0.25 millimeters, followed by adhesively attaching the sanded body to an appropriate backing. The sanding procedure permits routine production of extremely thin (about 0.05 millimeters) TLD bodies, and moreover serves to significantly reduce non-radiation-induced thermoluminescence. The composite dosimeters are rugged in use and can be subjected to annealing temperatures for increased accuracy.

  16. Thin thermoluminescent dosimeter and method of making same

    SciTech Connect

    Simons, G.G.; DeBey, T.M.

    1987-01-13

    An improved thermoluminescent ionizing radiation dosimeter of solid, extremely thin construction for more accurate low energy beta dosimetry is provided, along with a method of fabricating the dosimeter. In preferred forms, the dosimeter is a composite including a backing support (which may be tissue equivalent) and a self-sustaining body of solid thermoluminescent material such as LiF having a thickness of less than about 0.25 millimeters and a volume of at least about 0.0125 mm[sup 3]. In preferred fabrication procedures, an initially thick (e.g., 0.89 millimeters) TLD body is wet sanded using 600 grit or less sandpaper to a thickness of less than about 0.25 millimeters, followed by adhesively attaching the sanded body to an appropriate backing. The sanding procedure permits routine production of extremely thin (about 0.05 millimeters) TLD bodies, and moreover serves to significantly reduce non-radiation-induced thermoluminescence. The composite dosimeters are rugged in use and can be subjected to annealing temperatures for increased accuracy. 1 fig.

  17. [Establishment of optimal conditions at laboratory and pilot plant levels for the preparation of a protein isolated from Lupinus mutabilis].

    PubMed

    Rodríguez Pacheco, T; Aliaga, T; Schoeneberger, H; Gross, R

    1981-12-01

    Laboratory conditions were first investigated to determine are optimum processing parameters for the preparation of a protein isolate from the ground, defatted, commercial flakes of Lupinus mutabilis. The extraction variables were: pH (2-10); solvent to lupine ratio (5:1 to 40:1); temperature (28 degrees C - 60 degrees C) and time (10-50 min). The isoelectric point of the lupine protein was found to be pH 4.5 with a protein solubility higher than 80% above pH 8.0. Using 70-100 mesh, ground defatted flakes, and extracting at pH 8.7 for 60 min, a protein isolate was obtained on acidification to pH 4.5 which was 99.8 protein (dry basis), compared to 55.25% protein for the original material. This protein isolate represented 32% of the initial material and 57.6% of the initial nitrogen. When making pilot plant assays we found that the yield of protein isolate decreased to 20.4% of the original material and 36.4% of the initial nitrogen. The protein efficiency ratio for the protein isolate was 2.15 when supplemented with methionine, and had a digestibility of 89.33

  18. A One-Pot Self-Assembly Reaction to Prepare a Supramolecular Palladium(II) Cyclometalated Complex: An Undergraduate Organometallic Laboratory Experiment

    ERIC Educational Resources Information Center

    Fernandez, Alberto; Lopez-Torres, Margarita; Fernandez, Jesus J.; Vazquez-Garcia, Digna; Vila, Jose M.

    2012-01-01

    A laboratory experiment for students in advanced inorganic chemistry is described. Students prepare palladium(II) cyclometalated complexes. A terdentate [C,N,O] Schiff base ligand is doubly deprotonated upon reaction with palladium(II) acetate in a self-assembly process to give a palladacycle with a characteristic tetranuclear structure. This…

  19. Experimental determination of the photon-energy dependent dose-to-water response of TLD600 and TLD700 (LiF:Mg,Ti) thermoluminescence detectors.

    PubMed

    Schwahofer, Andrea; Feist, Harald; Georg, Holger; Häring, Peter; Schlegel, Wolfgang

    2017-03-01

    The aim of this study has been the experimental determination of the energy dependent dose-to-water response of TLD600 and TLD700 thermoluminescent detectors (Harshaw) in X-ray beams with mean photon energies from about 20 to 200keV in comparison with (60)Co gamma rays and 6MV X-rays. Experiments were carried out in collaboration with the German secondary standard laboratory PTW Freiburg. The energy dependent relative responses of TLD600 and TLD700 thermoluminescence detectors were determined at radiation qualities between 30kVp and 280kVp. The overall uncertainty of the measured values was characterized by standard deviations varying from 1.2 to 3%. The present results agree with previous studies on the energy dependent dose-to-water response of TLD100. As an application example, the results were used to measure doses associated with X-ray imaging in image-guided radiotherapy.

  20. YAlO3:Ce3+ powders: Synthesis, characterization, thermoluminescence and optical studies

    NASA Astrophysics Data System (ADS)

    Parganiha, Yogita; Kaur, Jagjeet; Dubey, Vikas; Shrivastava, Ravi

    2015-09-01

    Yttrium aluminum perovskite (YAP) is a promising high temperature ceramic material, known for its mechanical, structural and optical properties. YAP's also known as an ideal host material for solid-state lasers and phosphors. In this work, Ce3+ doped YAlO3 phosphors were synthesized by solid state reaction method, which is very suitable technique for large scale production. A prepared phosphor was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Photoluminescence spectra and Thermoluminescence (TL) glow curve study. The starting reagents used for sample preparation are Y2O3, Al2O3 and CeO2, boric acid used as a flux. Ratio of Y:Al was 1:1 which shows perovskite structure confirmed by the X-ray diffraction (XRD) study. The entire prepared sample was studied by PL excitation and emission spectra. Prominent peak at 446 nm (blue emission) which shows broad emission spectra of photoluminescence. It proves that prepared phosphor can act as a single host for blue emission of light and can be used for display applications. Commission Internationale de I'Eclairage (CIE) techniques proves the blue emission of light (x = .148, y = .117). TL glow curve analysis of prepared phosphor shows the prominent peak at 189 °C for the variable UV exposure time and high temperature peak shows the more stability and less fading in the prepared phosphor. Kinetic data of prepared phosphor were evaluated by peak shape method for variable UV exposure time (5-25 min).

  1. Prepare, Do, Review: A Skills-Based Approach for Laboratory Practical Classes in Biochemistry and Molecular Biology

    ERIC Educational Resources Information Center

    Arthur, Peter; Ludwig, Martha; Castelli, Joane; Kirkwood, Paul; Attwood, Paul

    2016-01-01

    A new laboratory practical system is described which is comprised of a number of laboratory practical modules, each based around a particular technique or set of techniques, related to the theory part of the course but not designed to be dependent on it. Each module comprises an online recorded pre-lab lecture, the laboratory practical itself and…

  2. Thermoluminescence (TL) characterisation and dating feasibility of ancient glass mosaic

    NASA Astrophysics Data System (ADS)

    Chiavari, Cristina; Martini, Marco; Sibilia, Emanuela; Vandini, Mariangela

    2001-12-01

    To achieve a better comprehension of the thermoluminescence (TL) properties and dating feasibility of mosaic glasses, a study on the connections between chemical composition and general TL behaviour of glass tesserae has been carried out. Elemental analysis of the samples has been performed through electron microscopy with microprobe, inductively coupled plasma and X-ray fluorescence spectrometry. Preliminary results, relative to the study of the TL behaviour of different groups of glass mosaic tesserae, classified by provenance and by chemical analyses, are reported and discussed.

  3. Defect centres and thermoluminescence in SrS : Bi phosphor

    NASA Astrophysics Data System (ADS)

    Singh, V.; Tiwari, M.; Rao, T. K. G.

    2004-11-01

    Thermoluminescence (TL) and electron spin resonance studies have been carried out on SrS:Bi phosphor. The TL glow curve is broad and indicates a dominant peak at 120 degrees C with two additional peaks, not clearly resolved, appearing as shoulders at around 180 and 250 degrees C. Two defect centres are observed at room temperature. One of them is characterized by an isotropic g-value 2.0034 and is assigned to an F+ centre. Step annealing measurements indicate a possible association between the F+ centre and the three TL peaks.

  4. Method of improving BeO as a thermoluminescent detector

    DOEpatents

    Gammage, Richard B.; Thorngate, John H.; Christian, Danny J.

    1980-01-01

    Measurements of radiation exposure below 1 mR are possible with a BeO ceramic thermoluminescent detector (TLD) by treating the TL signal in a manner that discriminates against an interferring pyroelectric incandescence (PI). This is accomplished by differentiating the signals electronically to cause the composite signal to cross the baseline. A zero-crossing detector then senses and clips the negative-going portion of the signal. The resultant signal is integrated, producing a result wherein the true TL signal is substantially greater than the PI signal.

  5. Thermoluminescence curves simulation using genetic algorithm with factorial design

    NASA Astrophysics Data System (ADS)

    Popko, E. A.; Weinstein, I. A.

    2016-05-01

    The evolutionary approach is an effective optimization tool for numeric analysis of thermoluminescence (TL) processes to assess the microparameters of kinetic models and to determine its effects on the shape of TL peaks. In this paper, the procedure for tuning of genetic algorithm (GA) is presented. This approach is based on multifactorial experiment and allows choosing intrinsic mechanisms of evolutionary operators which provide the most efficient algorithm performance. The proposed method is tested by considering the “one trap-one recombination center” (OTOR) model as an example and advantages for approximation of experimental TL curves are shown.

  6. Thermoluminescence characteristics of Israeli household salts for retrospective dosimetry in radiological events

    NASA Astrophysics Data System (ADS)

    Druzhyna, S.; Datz, H.; Horowitz, Y. S.; Oster, L.; Orion, I.

    2016-06-01

    Following a nuclear accident or terror attack involving the dispersal of radioactive substances, radiation dose assessment to first responders and the members of the public is essential. The need for a retrospective assessment of the radiation dose to those possibly affected is, therefore, obligatory. The present study examines the potential use of Israeli household salt as a retrospective dosimeter (RD). The experiments were carried out on Israeli salt samples (NaCl) following a Nielsen market track survey based on scanning data representing the barcoded market, including organized and independent retail chains and a sample of private minimarkets and supermarkets. The technique used was thermoluminescence (TL) dosimetry. Salt samples were exposed to levels of dose from 0.5 mGy to 300 Gy at the Israeli Secondary Standard Dosimetry Laboratory of the Soreq Nuclear Research Center using a calibrated 137Cs source. Our emphasis has been on a detailed investigation of the basic dosimetric characteristics of the salts including: (i) glow curve analysis (ii) individual glow peak dose response (iii) reproducibility (iv) estimation of minimal measurable dose (v) effect of nitrogen readout, (vi) influence of humidity during pre-irradiation storage and (vii) light induced fading. The results are sufficiently favorable to lead to the conclusion that the Israeli household salts can serve as a pragmatic potential candidate for RD under certain restricted conditions. Occasional pre-calibration of the major salt brands in a dedicated laboratory may be essential depending on the required accuracy in the estimation of dose and consequent clinical evaluation.

  7. Thermoluminescence of K-Mg-Al-Zn fluorophosphate glass

    NASA Astrophysics Data System (ADS)

    Thomas, Sunil; Chithambo, M. L.

    2017-02-01

    The thermoluminescence of beta irradiated K-Mg-Al-Zn fluorophosphate glass is reported. A glow-curve corresponding to 10 Gy measured at 1 °C/s shows two peaks, a weaker-intensity one at 70 °C and a more prominent one at 235 °C, the subject of this report. The main peak was observed to fade with delay between irradiation and measurement and specifically, by 11% in 15 h. Its dose response is superlinear in the dose range 1-190 Gy although the change was linear for the initial 10 Gy. Regarding kinetic analysis, the activation energy of the higher temperature peak was evaluated as 1.31 eV and that of the lower temperature peak was found as 0.47 eV. It was also noted that the main peak is affected by thermal quenching with an activation energy for thermal quenching equal to 1.37 eV. It is proposed that the mechanism associated with the thermoluminescence in K-Mg-Al-Zn fluorophosphate glass is that electrons trapped by the metal cations are released during heating and then recombine with holes at oxygen sites.

  8. Validity of repeated initial rise thermoluminescence kinetic parameter determinations

    SciTech Connect

    Kierstead, J.A.; Levy, P.W.

    1990-01-01

    The validity of thermoluminescence (TL) analysis by repeated initial rise measurements has been studied by computer simulation. Thermoluminescence described by 1st Order, 2nd Order, General One Trap and Interactive TL Kinetics was investigated. In the simulation each of the repeated temperature increase and decrease cycles contains a linear temperature increase followed by a decrease appropriate for radiative cooling, i.e. the latter is approximated by a decreasing exponential. The activation energies computed from the simulated emission are readily compared with those used to compute the TL emission. In all cases studied, the repeated initial rise technique provides reliable results only for single peak glow curves or for glow curves containing peaks that do not overlap and, if sufficiently separated, the lowest temperature peak in multipeak curves. Also the temperatures, or temperature cycles corresponding to correct activation energies occur on the low temperature side of the normal glow curve, often well below the peak temperature. A variety of misleading and/or incorrect results an be obtained when the repeated initial rise technique is applied to TL systems that produce overlapping peaks in the usual glow curve. 6 refs., 10 figs.

  9. Thermoluminescence responses of terbium-doped magnesium orthosilicate with different synthesis conditions.

    PubMed

    Wang, Y; Jiang, Y; Chu, X; Xu, J; Townsend, P D

    2014-03-01

    Numerous materials have been proposed for thermoluminescence dosemeter, and the example of highest sensitivity is cited as magnesium orthosilicate doped with terbium (Mg2SiO4:Tb). Nevertheless, the material is currently not commercially attractive because the sensitivity varies greatly with synthesis techniques. This is a multi-parameter problem, and the current work explores some of the conditions required to consistently enhance the response. These new results show that to get a high TL response, Mg2SiO4:Tb should be prepared at a high temperature of at least 1500°C, for sintering times of several hours. In the current example, the optimum time was 6 h. Signals also vary with the terbium activator concentration, and good responses were achieved with a concentration of Tb at 5 wt %. Overall, this suggests that with careful preparation, the potentially high dosimetry performance might be exploited. The inherent problem of concentration quenching is considered, and the potential benefits of processing the powder with pulse laser annealing are reviewed in the light of successful luminescence and laser studies for rare-earth-doped laser materials.

  10. Thermoluminescence characterization of Dy(3+) -activated Mg₅ (BO₃ )₃ F low Z(eff) phosphor.

    PubMed

    Wani, Javaid A; Dhoble, N S; Dhoble, S J

    2013-01-01

    Thermoluminescence characteristics of Dy(3+) -activated Mg₅ (BO₃ )₃ F low Z(eff) phosphor are described. The Mg₅ (BO₃ )₃ F phosphor doped with Dy(3+) as activator was prepared by the modified solid-state reaction. Formation of the compound was confirmed by use of X-ray powder diffraction. The X-ray powder diffraction pattern of the as-prepared compound shows a good match with the available JCPDS data. The γ-irradiated Mg₅ (BO₃ )₃ F:Dy(3+) phosphor shows a simple glow curve peaking at about 148°C indicating that only one type of trap is being activated within a particular temperature range. The kinetic parameters, including activation energy and frequency factor were determined using Chen's method. The activation energy and frequency factors were 0.75 eV and 4.508 × 10(9) /s respectively. The Z(eff) ofMg₅ (BO₃ )₃ F:Dy(3+) phosphor was 9.84.

  11. Synthesis and thermoluminescence characterizations of Sr2B5O9Cl:Dy3+ phosphor for TL dosimetry.

    PubMed

    Oza, Abha H; Dhoble, N S; Park, K; Dhoble, S J

    2015-09-01

    The photoluminescence (PL) and thermoluminescence (TL) displayed by Dy-activated strontium haloborate (Sr2 B5 O9 Cl) were studied. A modified solid-state reaction was employed for the preparation of the phosphor. Photoluminescence spectra showed blue (484 nm) and yellow (575 nm) emissions due to incorporation of Dy(3+) into host matrix. The Dy-doped (0.5 mol%) Sr2 B5 O9 Cl was studied after exposure to γ-irradiation and revealed a prominent glow curve at 261°C with a small hump around 143°C indicating that two types of traps were generated. The glow peak at the higher temperature side (261°C) was more stable than the lower temperature glow peak. The TL intensity was 1.17 times less than that of the standard CaSO4 :Dy thermoluminescence dosimetry (TLD) phosphor, the phosphor showed a linear dose-response curve for different γ-ray irradiation doses (0.002-1.25 Gy) and fading of 5-7% was observed for higher temperature peaks upon storage. Trapping parameters and their estimated error values have been calculated by Chen's peak shape method and by the initial rise method. Values of activation energies estimated by both these techniques were comparable. The slight difference in activation energy values calculated by Chen's peak shape method indicated the formation of two kinds of traps Furthermore, slight differences in frequency values are due to various escaping and retrapping probabilities.

  12. Solving the AI Planning Plus Scheduling Problem Using Model Checking via Automatic Translation from the Abstract Plan Preparation Language (APPL) to the Symbolic Analysis Laboratory (SAL)

    NASA Technical Reports Server (NTRS)

    Butler, Ricky W.; Munoz, Cesar A.; Siminiceanu, Radu I.

    2007-01-01

    This paper describes a translator from a new planning language named the Abstract Plan Preparation Language (APPL) to the Symbolic Analysis Laboratory (SAL) model checker. This translator has been developed in support of the Spacecraft Autonomy for Vehicles and Habitats (SAVH) project sponsored by the Exploration Technology Development Program, which is seeking to mature autonomy technology for the vehicles and operations centers of Project Constellation.

  13. Pre-Service Chemistry Teachers' Competencies in the Laboratory: A Cross-Grade Study in Solution Preparation

    ERIC Educational Resources Information Center

    Karatas, F. O.

    2016-01-01

    One of the prerequisites for chemistry teacher candidates is to demonstrate certain laboratory skills. This article aims to determine and discuss the competencies of pre-service chemistry teachers in a chemistry laboratory context working with solution chemistry content. The participants in this study consisted of a group of pre-service chemistry…

  14. Prepare, Do, Review: A Model Used to Reduce the Negative Feelings towards Laboratory Classes in an Introductory Chemistry Undergraduate Unit

    ERIC Educational Resources Information Center

    Spagnoli, Dino; Wong, Lawrence; Maisey, Shannan; Clemons, Tristan D.

    2017-01-01

    Student feelings towards the laboratory component of an introductory chemistry unit were evaluated in an action research study, over a three-year period at the University of Western Australia. In 2013 we found that the percentage of students with negative feelings towards the laboratory increased over the duration of a semester. In 2014 we…

  15. Thermoluminescence and the origin of the dark matrix of Fayetteville and similar meteorites

    NASA Technical Reports Server (NTRS)

    Haq, Munir; Hasan, Fouad A.; Sears, Derek W. G.; Moore, Carleton B.; Lewis, Charles F.

    1989-01-01

    The paper presents measurements of the induced thermoluminescence properties and carbon contents of the dark matrix and light clasts of six regolith breccias. For all of the meteorites, the dark matrix has a lower mean thermoluminescence sensitivity than the light clasts; the extent of the difference depends on the meteorite. The data suggest the formation of the dark matrix by comminution of the light clasts with the addition of a component, perhaps CM-like chondrites, with thermoluminescence properties distinct from those of ordinary chondrites.

  16. Synthesis, characterization, thermoluminescence and optical studies of Eu3+ doped Y2SiO5 phosphor

    NASA Astrophysics Data System (ADS)

    Parganiha, Yogita; Kaur, Jagjeet; Dubey, Vikas; Chandrakar, Deepika

    2015-01-01

    The present paper reports thermoluminescence (TL) glow curves and photoluminescence (PL) studies of europium doped yttrium silicate (Y2SiO5:Eu3+). The samples were prepared by the modified Solid state method which is the most suited method for large scale production. Starting material used for sample preparation was Y2O3, SiO2 and Eu2O3 with variable concentration of europium. A prepared sample was characterized by XRD (X-ray diffraction) and crystallite size found 20-50 nm in size. The PL excitation spectra was found at 265 and 395 nm while the emission spectra was found at 580, 588, 595, 598, 612, 615, 623 and 626 nm, the emission peak at 612 nm was most intense peak for all Eu3+ concentration. The effect of Eu3+ concentration on PL intensity was studied and found that intensity increases with increasing concentration up to 2.5 mol% of Eu3+. Commission Internationale de l'Eclairage co-ordinate (CIE) of this phosphor is (0.65, 0.31) in the red region. TL glow curves were recorded for different doses of UV exposure at a heating rate of 6.7 °C s-1. The kinetic parameters as activation energy 'E', the order of kinetics 'b', and the frequency factor 's' of Y2SiO5:Eu3+ have been calculated by using peak shape method. The sample shows general order kinetics. The effect of Eu3+ concentration on TL intensity was also studied and found that the intensity increases linearly up to 1 mol% and then decreases with increasing concentration of Eu3+. The present phosphor acts as a single host for red emission display devices and light emitting diode (LED) as well as may be used for thermoluminescence dosimetric material under UV exposure.

  17. Thermoluminescent dose reconstruction using quartz extracted from unfired buildings

    NASA Astrophysics Data System (ADS)

    Campos, Simara S.; Almeida, Geângela M.; Cardoso, Leandro X.; de Lima, Leonardo L.; A, Carlos; de Souza, Susana O.

    2010-11-01

    The use of thermoluminescence (TL) is very useful for application in retrospective dosimetry, that is, for inference of the dose of radiation undergone for some material. The calculation of the lifetime of TL peaks can help to clarify which TL intensity is due to the dose of environmental radiation and which is proceeding from the accident with radiation. In this work, the kinetic order (b), activation energy (Et) and the frequency factor (s) were obtained for quartz samples that had been extracted from unfired buldings. It was observed the occurrence of peaks in the 150 °C - 250 °C range, that corresponds to a range commonly used in retrospective dosimetry, due to its shorter lifetime when compared with TL geological signal. The analysis of the peaks was done through several well known methods, namely the peak shape (PS), curve fitting (CF) and heating rate (HR) methods. To confirm the structure of the sample, additional X-ray diffraction was made.

  18. Hydrothermally synthesized barium fluoride nanocubes for thermoluminescence dosimetry

    NASA Astrophysics Data System (ADS)

    Bhadane, Mahesh S.; Dahiwale, S. S.; Bhoraskar, V. N.; Dhole, S. D.

    2016-05-01

    In this work, we report a hydrothermally synthesized Dy doped BaF2 (BaF2:Dy) nanocubes and its Thermoluminescence studies. The synthesized BaF2:Dy samples was found to posses FCC structure and having average size ~ 60-70 nm, as revealed through X-Ray Diffraction. Cubical morphology having size ~90 nm was observed from TEM analysis. The 60Co γ- ray irradiated BaF2:Dy TL dosimetric experiments shows a pre-dominant single glow peak at 153 °C, indicating a single level trap present as a metastable state. Furthermore, BaF2:Dy nanophosphor shows a sharp linear response from 10 Gy to 3 kGy, thus it can be applicable as a gamma dosimeter.

  19. Latest developments in silica-based thermoluminescence spectrometry and dosimetry.

    PubMed

    Bradley, D A; Jafari, S M; Siti Shafiqah, A S; Tamcheck, N; Shutt, A; Siti Rozaila, Z; Abdul Sani, S F; Sabtu, Siti Norbaini; Alanazi, Abdulaziz; Amouzad Mahdiraji, G; Abdul Rashid, H A; Maah, M J

    2016-11-01

    Using irradiated doped-silica preforms from which fibres for thermoluminescence dosimetry applications can be fabricated we have carried out a range of luminescence studies, the TL yield of the fibre systems offering many advantages over conventional passive dosimetry types. In this paper we investigate such media, showing emission spectra for irradiated preforms and the TL response of glass beads following irradiation to an (241)Am-Be neutron source located in a tank of water, the glass fibres and beads offering the advantage of being able to be placed directly into liquid. The outcomes from these and other lines of research are intended to inform development of doped silica radiation dosimeters of versatile utility, extending from environmental evaluations through to clinical and industrial applications.

  20. The natural thermoluminescence of meteorites. III - Lunar and basaltic meteorites

    NASA Technical Reports Server (NTRS)

    Sears, Derek W. G.; Benoit, Paul H.; Sears, Hazel; Batchelor, J. D.; Symes, Steve

    1991-01-01

    Natural thermoluminescence (TL) data were obtained to investigate recent thermal and radiation histories of the lunar meteorite MacAlpine Hills 88104/5 and 65 eucrites, howardites, diogenites, and mesosiderites. All these meteorites have low levels of natural TL compared to chondrites, which is primarily because they display anomalous fading. Some meteorites have especially low natural TL which must reflect heating within the last 100,000-1,000,000 y. The parameters for TL decay were determined assuming plausible values for cosmic ray dose rate and that the natural TL of MAC88104/5 was totally drained by ejection from the moon. The obtained parameters for TL decay suggest that the moon-earth transit times for MAC88104 and MAC88105 were 2,000 and 1,800 y, respectively, compared with 19,000 and 2,500 y for Y791197 and ALHA81005, respectively.

  1. Natural thermoluminescence profiles in lunar cores and implications for meteorites

    NASA Technical Reports Server (NTRS)

    Benoit, P. H.; Sears, D. W. G.

    1993-01-01

    Meteorites and lunar samples have been irradiated by high energy cosmic rays, typically for millions of years. In addition to producing isotopic changes, the irradiation creates ionization which may be recorded in the form of stored thermoluminescence (TL) in certain minerals, the most important of which is feldspar. One aspect of interpreting the TL of these samples is the effect of 'shielding' or depth control, which is particularly important for meteorites, since they have lost an unknown amount of mass during atmospheric entry. Here we report theoretical calculations which we compare with samples from lunar cores for which we have excellent stratigraphic control. We then discuss the implications for these results for the TL of meteorites, which have a different irradiation geometry. We find that, in general, calculated profiles are similar to those observed in lunar samples and meteorites. Additional effects, such as orbital (thermal) history and terrestrial age must also be considered in the case of meteorites.

  2. Dating loess up to 800 ka by thermoluminescence

    SciTech Connect

    Berger, G.W. ); Pillans, B.J. ); Palmer, A.S. )

    1992-05-01

    Thermoluminescence (TL) ages agreeing with expected ages have been obtained for 13 loess samples spanning the age range from 20 to 800 ka. The authors samples are from Alaska and North Island, New Zealand, and are unusual in TL dating studies of loess older than 80-100 ka by having independent age assignments that are generally well constrained, from ages of associated tephra beds. With the polymineral fine-silt-sized (4-11 {mu}m) grains the partial-bleach TL technique yielded expected ages up to about 350 ka, whereas the total-bleach method gave accurate ages in the range 100 to 800 ka. Thus, the much disputed upper age limit of 100-150 ka for the TL dating of loess now appears to be sample and worker dependent, rather than a global property of the TL signals in the TL-dominant feldspars.

  3. Thermoluminescence and optically stimulated luminescence properties of natural barytes.

    PubMed

    Kitis, G; Kiyak, N G; Polymeris, G S

    2010-12-01

    Heavy, baryte-loaded, concrete is commonly used as radiation shielding material around high energy particle accelerators. Concrete samples received from a shielding block located at CERN cite contain many crystalline inclusions which were identified as barytes by X-ray diffraction analysis and separated by their color, classified as white, orange and green. Basic properties of thermoluminescence (TL) and optically stimulated luminescence (OSL) signals of these barytes samples such as thermal and optical stability, repeatability and mainly the linearity of both their luminescence responses were investigated as a function of beta dose. These results are also discussed regarding detailed investigation on the correlation between TL and OSL signals and their implications for retrospective dosimetry.

  4. Thermoluminescence dating of sediments: a re-extension of age range for loess

    SciTech Connect

    Johnson, R.J.; Stipp, J.J.; Wintle, A.G.; Tamers, M.A.

    1985-01-01

    Thermoluminescence (TL) dating of wind blown minerals provides a technique whereby non-carbonaceous sediments could be dated to several hundred thousand years. Two recent reports, however, indicate age underestimates on feldspar in some European loesses older than 50 ka, the effect increasing in severity with age. Suggested causes include decay of luminescence centers, or does dependent sensitivity changes. Data presented in this paper do not support these limitations or explanations. TL provides 3 separate techniques of dating sediments, which, when used together, prove to be efficient internal cross checks for mineralogical anomalies or inconsistencies created by any of the individual methods. In the authors studies each sample was dated by all 3 methods whereas the Europeans analyses employed only the Regeneration technique. This work presents results from loess sections in Mississippi, Illinois and Alaska. These show excellent internal consistency, and consistency with both independent dating methods and stratigraphy, with 2 exceptions. Both exceptions were by the Regen technique giving age underestimates up to 30%. The underestimates were found to be caused by a change in mineral sensitivity resulting from the Regen requirements of strong laboratory light-bleaching followed by irradiations. A simple method to test and correct for this condition is presented. TL thus appears to remain a powerful and increasingly flexible method of sediment dating.

  5. Thermoluminescence constraints on the metamorphic, shock, and brecciation history of basaltic meteorites

    NASA Technical Reports Server (NTRS)

    Batchelor, J. D.; Sears, Derek W. G.

    1991-01-01

    The metamorphic, shock, and brecciation history of 18 eucrites, 13 howardites, 6 diogenites, and 15 mesosiderites is investigated via induced thermoluminescence measurements performed on them. The eucrites show a 15-fold range of TL sensitivities, which correlate with petrographic indicators of metamorphic intensity. The temperature of the dominant TL peak observed for basaltic meteorites, and experiments in which four eucrites with diverse petrographic properties were annealed at various temperatures in the laboratory, suggests that the metamorphic equilibration temperatures for most basaltic meteorites were not more than 800 C. Assuming this temperature was typical of conditions during metamorphism, then burial depths for type-above-5 eucrites were greater than 350 m and less than 50 m for type-2 eucrites. Since TL peak temperatures are related to the degree of disorder in the Al, Si chain in feldspar, the present data provide independent evidence for very slow cooling rates for mesosiderites and for the slower cooling rates for some cumulate eucrites relative to equilibrated noncumulate eucrites.

  6. Noninvasive measurement of radiopharmaceutical time–activity data using external thermoluminescent dosimeters (TLDs)

    NASA Astrophysics Data System (ADS)

    Lu, Cheng-Chang; Dong, Shang-Lung; Lin, Hsin-Hon; Ni, Yu-Ching; Jan, Meei-Ling; Chuang, Keh-Shih

    2017-02-01

    In this study, we present a new method for estimating the time–activity data using serial timely measurements of thermoluminescent dosimeters (TLDs). The approach is based on the combination of the measurement of surface dose using TLD and Monte Carlo (MC) simulation to estimate the radiopharmaceutical time–activity data. It involves four steps: (1) identify the source organs and outline their contours in computed tomography images; (2) compute the S values on the body surface for each source organ using a MC code; (3) obtain a serial measurement of the dose with numerous TLDs placed on the body surface; (4) solve the dose–activity equation to generate organ cumulative activity for each period of measurement. The activity of each organ at the time of measurement is simply the cumulative activity divided by the timespan between measurements. The usefulness of this method was studied using a MC simulation based on an Oak Ridge National Laboratory mathematical phantom with 18F-FDG filled in six source organs. Numerous TLDs were placed on different locations of the surface and were repeatedly read and replaced. The time–activity curves (TACs) of all organs were successfully reconstructed. Experiments on a physical phantom were also performed. Preliminary results indicate that it is an effective, robust, and simple method for assessing the TAC. The proposed method holds great potential for a range of applications in areas such as targeted radionuclide therapy, pharmaceutical research, and patient-specific dose estimation.

  7. From films to thermoluminescence dosemeters: the Greek Atomic Energy Commission experience.

    PubMed

    Carinou, E; Drikos, G; Hourdakis, C; Hyvönen, H; Kamenopoulou, V

    2001-01-01

    The personnel dosimetry department of the Greek Atomic Energy Commission (GAEC) assures the individual monitoring of almost 8000 occupationally exposed workers. Thermoluminescence dosimetry systems will replace the existing photographic dosimetry system for the individual monitoring with the joint support of IAEA and GAEC. The thermoluminescence dosimetry system consists of two automated readers, one automated irradiator and about 20,000 dosemeters purchased from the Rados Co. The properties of two thermoluminescent materials have been compared: LiF has been chosen for the whole-body dosemeter configuration and Li2B4O7 for the extremities. The technical evaluation of the system has been performed according to the European and IEC standards. The overall uncertainty has been calculated. The existing database system, and the accounting and dispatching procedures have been adapted to the new demands. The system became operational on March 2000, and the official distribution of thermoluminescence dosemeters has begun.

  8. The Interpretation of Natural Thermoluminescence Data for Meteorites: Theoretical Basis and Practical Application

    NASA Technical Reports Server (NTRS)

    Benoit, P. H.; Sears, D. W. G.

    2000-01-01

    Natural thermoluminescence (TL) of ordinary chondrites reflects their irradiation and thermal history. We discuss the quantitative aspects of TL interpretation, with an emphasis on the terrestrial history of Antarctic meteorites and the orbital history of modern falls.

  9. Thermoluminescence Sensitivity and Thermal History of Unequilibrated Ordinary Chondrites: Review and Update

    NASA Technical Reports Server (NTRS)

    Benoit, P. H.; Ninagawa, K.; Sears, D. W. G.

    2000-01-01

    We report on the induced thermoluminescence (TL) data for 102 unequilibrated ordinary chondrites. We discuss these data in terms of pairing, weathering, and parent body thermal history. We identify ten possible meteorites of petrologic types 3.0-3.1.

  10. Topics in Chemical Instrumentation: Cl. Thermoluminescence. Part III. Application to Archeological Dating.

    ERIC Educational Resources Information Center

    Manche, Emanuel P.; Ewing, Galen W., Ed.

    1979-01-01

    Thermoluminescence and its application to archeological dating are considered in this article. Descriptions are given of the method, the required doses, absolute and relative dating, complications, and the relation of this type of dating to other methods. (SA)

  11. Prepare, Do, Review: A skills-based approach for laboratory practical classes in biochemistry and molecular biology.

    PubMed

    Arthur, Peter; Ludwig, Martha; Castelli, Joane; Kirkwood, Paul; Attwood, Paul

    2016-05-06

    A new laboratory practical system is described which is comprised of a number of laboratory practical modules, each based around a particular technique or set of techniques, related to the theory part of the course but not designed to be dependent on it. Each module comprises an online recorded pre-lab lecture, the laboratory practical itself and a post-lab session in which students make oral presentations on different aspects of the practical. Each part of the module is assessed with the aim of providing rapid feedback to staff and students. Each laboratory practical is the responsibility of a single staff member and through this "ownership," continual review and updating is promoted. Examples of changes made by staff to modules as a result of student feedback are detailed. A survey of students who had experienced both the old-style laboratory course and the new one provided evidence of increased satisfaction with the new program. The assessment of acquired shills in the new program showed that it was much more effective than the old course. © 2016 by The International Union of Biochemistry and Molecular Biology, 44:276-287, 2016.

  12. Thermoluminescent dosimetric comparison for two different MgB4O7:Dy production routes

    NASA Astrophysics Data System (ADS)

    Souza, L. F.; Vidal, R. M.; Souza, S. O.; Souza, D. N.

    2014-11-01

    There are several routes employed for the production of synthetic magnesium tetraborate, for example, sol-gel method, combustion, wet reaction synthesis, solid-state route and precipitation (crystal growth). The most commonly used synthesis methods are the wet reaction (precipitation) and solid-state synthesis; both production routes are efficient, but is very difficult to find a direct comparison for them. The present work proposes a direct comparison of both production routes used for magnesium tetraborate synthesis for thermoluminescent (TL) dosimetry. In this work, MgB4O7:Dy was prepared by both methods, wet reaction or precipitation-route 1, and solid-state synthesis -route 2, with the same amount of dopant (0.1%). In the first part of work, the crystalline phases were confirmed by X-ray diffraction (XRD) and it was observed that MgB4O7:Dy can be obtained satisfactorily through both routes, although a very intense crystalline phase of H3BO3 for the powder produced through route 1 was observed. The dose response curve of MgB4O7 pellets (produced for both routes) presents linear behavior when the materials are irradiated with 60Co in the dose range of 10-100 Gy. The results showed that both methods produce MgB4O7:Dy efficiently; however, solid-state synthesis produces MgB4O7:Dy more sensitive to gamma radiation.

  13. CdSiO3:Pr3+ nanophosphor: Synthesis, characterization and thermoluminescence studies

    NASA Astrophysics Data System (ADS)

    Sunitha, D. V.; Manjunatha, C.; Shilpa, C. J.; Nagabhushana, H.; Sharma, S. C.; Nagabhushana, B. M.; Dhananjaya, N.; Shivakumara, C.; Chakradhar, R. P. S.

    2012-12-01

    A series of Pr3+ (1-9 mol%) doped CdSiO3 nanophosphors have been prepared for the first time by a low temperature solution combustion method using oxalyldihydrizide (ODH) as a fuel. The final product was characterized by Powder X-ray diffraction (PXRD), Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), and UV-Vis spectroscopy. The average crystallite size was calculated using Debye-Scherrer's formula and Williamson-Hall (W-H) plots and found to be in the range 31-37 nm. The optical energy band gap (Eg) of undoped for Pr3+ doped samples were estimated from Tauc relation which varies from 5.15-5.36 eV. Thermoluminescence (TL) properties of Pr3+ doped CdSiO3 nanophosphor has been investigated using γ-irradiation in the dose range 1-6 kGy at a heating rate of 5 °C s-1. The phosphor shows a well resolved glow peak at ˜171 °C along with shouldered peak at 223 °C in the higher temperature side. It is observed that TL intensity increase with increase of Pr3+ concentration. Further, the TL intensity at 171 °C is found to be increase linearly with increase in γ-dose which is highly useful in radiation dosimetry. The kinetic parameters such as activation energy (E), frequency factor (s) and order of kinetics was estimated by Luschiks method and the results are discussed.

  14. Photoluminescence and thermoluminescence characteristics of Sr3 B2 O6 :Eu(2+) yellow phosphor.

    PubMed

    Ho Van, Tuyen; Nguyen Manh, Son; Vu Xuan, Quang; Bounyavong, Sengthong

    2016-08-01

    Sr3 B2 O6 :Eu(2+) yellow phosphor was prepared by the combustion method. The crystalline structure, photoluminescence and thermoluminescence properties of Sr3 B2 O6 :Eu(2+) were investigated extensively. The X-ray diffraction result indicates that the Sr3 B2 O6 :Eu(2+) phosphor exhibited a rhombohedral crystal structure. The emission spectra under a 435 nm excited wavelength showed an intense broad band peaking at 574 nm, which corresponds to the 4f(6) 5d(1) → 4f(7) transition of Eu(2+) ion. There were two different sites of Sr replaced by Eu in host lattice. The concentration quenching process between Eu(2+) ions is determined and the corresponding concentration quenching mechanism was verified as dipole-quadrupole interaction. The glow curve under 3 Gy β- ray irradiation had the glow peak at 160°C and the average activation energy was defined as about 0.98 eV. Copyright © 2015 John Wiley & Sons, Ltd.

  15. Synthesis, characterization and thermoluminescence studies of Mn-doped ZnS nanoparticles.

    PubMed

    Chandrakar, Raju Kumar; Baghel, R N; Chandra, B P

    2016-03-01

    ZnS:Mn nanoparticles were prepared by a chemical precipitation method and characterized by X-ray diffraction (XRD), field emission gun scanning electron microscope (FEGSEM), and high resolution transmission electron microscopy (HRTEM). Capping agent (mercaptoethanol) concentrations used were 0 M, 0.005 M, 0.01 M, 0.015 M, 0.025 M, 0.040 M, and 0.060 M, and resulted in nanoparticles sizes of 2.98 nm, 2.9 nm, 2.8 nm, 2.7 nm, 2.61 nm, 2.2 nm and 2.1 nm, respectively. The thermoluminescence (TL) glow curve was recorded by heating the sample exposed to UV-radiation, at a fixed heating rate 1°C sec(-1). The TL intensity initially increased with temperature, attained a peak value Im for a particular temperature, and then decreased with further increase in temperature. The peak TL intensity increased with decreasing nanoparticle size, whereas the temperature corresponding to the peak TL intensity decreased slightly with reducing nanocrystal size. As a consequence of increase in surface-to-volume ratio and increased carrier recombination rates, the TL intensity increased with decreasing nanoparticle size. It was found that, whereas activation energy slightly decreased with decreasing nanoparticle size, the frequency factor decreased significantly with reduction in nanoparticle size.

  16. Thermoluminescence dating analysis at the site of an ancient brick structure at Pengkalan Bujang, Malaysia.

    PubMed

    Sabtu, Siti Norbaini; Mahat, Rosli Hj; Amin, Yusoff Mohd; Price, David M; Bradley, D A; Maah, Mohd Jamil

    2015-11-01

    Bujang Valley is a well-known historical complex found in the north-west of peninsular Malaysia; more than 50 ancient monuments and hundreds of artefacts have been discovered throughout the area. The discovery of these suggests Bujang Valley to have been an important South East Asian trading centre over the period from the 10th to 14th centuries. Present work concerns thermoluminescence (TL) dating analysis of shards collected from a historic monument located at Pengkalan Bujang in Bujang Valley. All the shards were prepared using the fine grain technique and the additive dose method was applied in determining the paleodose of each shard. The annual dose rate was obtained by measuring the concentration of naturally occurring radionuclides (U, Th and K) in the samples and their surroundings. The TL ages of the shards were found to range between 330±21 years and 920±69 years, indicative of the last firing of the bricks and tiles from which the shards originated, some dating back to the period during which the historical complex remained active.

  17. Effect of capping agent concentration on thermoluminescence and photoluminescence of copper-doped zinc sulfide nanoparticles.

    PubMed

    Wanjari, Lata; Bisen, D P; Brahme, Namita; Sahu, Ishwar Prasad; Sharma, Ravi

    2015-08-01

    Copper-doped zinc sulfide (ZnS:Cu) nanoparticles with varying concentrations of capping agent were prepared using a chemical route technique. These particles were characterized by scanning electron microscopy (SEM), transmission electron microscopy and X-ray diffraction (XRD). Optical absorption studies showed that the absorption edge shifted towards the blue region as the concentration of the capping agent increased. Using effective mass approximation, calculation of the nanoparticle size indicated that effective band gap energy increases with decreasing particle size. The thermoluminescence (TL) properties of sodium hexameta phosphate (SHMP)-passivated ZnS:Cu nanoparticles were investigated after UV irradiation at room temperature. The TL glow curve of capped ZnS:Cu showed variations in TL peak position and intensity with the change in capping agent concentration. The photoluminescence (PL) spectra of ZnS:Cu nanoparticles excited at 254 nm exhibited a broad green emission band peaking around 510 nm, which confirmed the characteristic feature of Zn(2+) as well as Cu(2+) ions as the luminescent centres in the lattice. The PL spectra of ZnS:Cu nanoparticles with increasing capping agent concentrations revealed that the emission becomes more intense and shifted towards shorter wavelengths as the sizes of the samples were reduced.

  18. Preparation for high altitude expedition and changes in cardiopulmonary and biochemical laboratory parameters with ascent to high altitude in transplant patients and live donors.

    PubMed

    Suh, Kyung-Suk; Kim, Taehoon; Yi, Nam-Joon; Hong, Geun

    2015-11-01

    High-altitude climbing has many risks, and transplant recipients should discuss the associated risks and means of preparation with their physicians. This study aimed to help prepare athletic transplant donors and recipients for mountain climbing and was designed to evaluate physical performance and changes in cardiopulmonary and biochemical laboratory parameters of transplant recipients and donors in extreme conditions of high altitude. Ten subjects-six liver transplant recipients, two liver donors, and one kidney transplant recipient and his donor-were selected for this expedition to Island Peak, Himalayas, Nepal. Six healthy subjects joined the group for comparison. Blood samplings, vital signs, and oxygen saturation were evaluated, as was the Lake Louise acute mountain sickness score. All transplant subjects and donors reached the base camp (5150 m), and two liver transplant recipients and a liver donor reached the summit (6189 m). The blood levels of immunosuppressants were well maintained. The serum erythropoietin level was significantly higher in transplant recipients taking tacrolimus. With proper preparation, certain liver transplant patients and donors can tolerate strenuous physical activity and can tolerate high altitude similarly to normal healthy control subjects without significant biochemical laboratory changes in liver and renal function.

  19. A comparative thermoluminescence and electron spin resonance study of synthetic carbonated A-type hydroxyapatite.

    PubMed

    Oliveira, L C; Rossi, A M; Baffa, O

    2012-03-01

    Intensity of the 150°C thermoluminescence peak of beta-irradiated carbonated synthetic A-type hydroxyapatite is approximately 12 times higher than that of the noncarbonated material. Deconvolution of the glow curve showed that this peak is a result of a trap distribution. An attempt was made to relate this thermoluminescence peak enhanced by carbonation with the ESR signal of the CO(2)(-) radical in natural or synthetic hydroxyapatite.

  20. Thermoluminescence dosimetry properties and kinetic parameters of lithium potassium borate glass co-doped with titanium and magnesium oxides.

    PubMed

    Hashim, S; Alajerami, Y S M; Ramli, A T; Ghoshal, S K; Saleh, M A; Abdul Kadir, A B; Saripan, M I; Alzimami, K; Bradley, D A; Mhareb, M H A

    2014-09-01

    Lithium potassium borate (LKB) glasses co-doped with TiO2 and MgO were prepared using the melt quenching technique. The glasses were cut into transparent chips and exposed to gamma rays of (60)Co to study their thermoluminescence (TL) properties. The TL glow curve of the Ti-doped material featured a single prominent peak at 230 °C. Additional incorporation of MgO as a co-activator enhanced the TL intensity threefold. LKB:Ti,Mg is a low-Z material (Z(eff)=8.89) with slow signal fading. Its radiation sensitivity is 12 times lower that the sensitivity of TLD-100. The dose response is linear at doses up to 10(3) Gy. The trap parameters, such as the kinetics order, activation energy, and frequency factor, which are related to the glow peak, were determined using TolAnal software.

  1. Effect of thermal annealing on the thermoluminescent properties of nano-calcium fluoride and its dose-response characteristics.

    PubMed

    Mundupuzhakal, J K; Biswas, R H; Chauhan, S; Varma, V; Acharya, Y B; Chakrabarty, B S

    2015-12-01

    Nano-CaF2, prepared by the co-precipitation method, was annealed under different annealing conditions to improve its thermoluminescence (TL) characteristics. Different annealing parameters, such as temperature (400-700°C), duration (1-4 h) and environment (vacuum and air), were explored. The effect on TL sensitivity, peak position (Tm) and full-width at half-maximum (FWHM) with respect to the different annealing conditions are discussed as they are the measure of crystallinity of the material. Annealing temperature of 500°C with annealing duration of two and a half hours in vacuum provided the highest luminescence response (i.e. maximum sensitivity, minimum peak temperature and FWHM). Wide detectable dose range (5 mGy to 2 kGy), absence of thermal quenching and sufficient activation energy (1.04 eV) of this phosphor make it suitable for dosimetric applications.

  2. X-ray absorption spectroscopy and X-ray photoelectron spectroscopy studies of CaSO 4:Dy thermoluminescent phosphors

    NASA Astrophysics Data System (ADS)

    Bakshi, A. K.; Jha, S. N.; Olivi, L.; Phase, D. M.; Kher, R. K.; Bhattacharyya, D.

    2007-11-01

    Extended X-ray absorption fine structure (EXAFS) measurements have been carried out on CaSO4:Dy phosphor samples at the Dy L3 edge with synchrotron radiation. Measurements were carried out on a set of samples which were subjected to post-preparation annealing at different temperatures and for different cycles. The EXAFS data have been analysed to find the Dy-S and Dy-O bond lengths in the neighbourhood of the Dy atoms in a CaSO4 matrix. The observations from EXAFS measurements were verified with XANES and XPS techniques. On the basis of these measurements, efforts were made to explain the loss of thermoluminescence sensitivity of CaSO4:Dy phosphors after repeated cycles of annealing at 400 °C in air for 1 h.

  3. Acid-Catalyzed Preparation of Biodiesel from Waste Vegetable Oil: An Experiment for the Undergraduate Organic Chemistry Laboratory

    ERIC Educational Resources Information Center

    Bladt, Don; Murray, Steve; Gitch, Brittany; Trout, Haylee; Liberko, Charles

    2011-01-01

    This undergraduate organic laboratory exercise involves the sulfuric acid-catalyzed conversion of waste vegetable oil into biodiesel. The acid-catalyzed method, although inherently slower than the base-catalyzed methods, does not suffer from the loss of product or the creation of emulsion producing soap that plagues the base-catalyzed methods when…

  4. Preparation and Viscosity of Biodiesel from New and Used Vegetable Oil: An Inquiry-Based Environmental Chemistry Laboratory

    ERIC Educational Resources Information Center

    Clarke, Nathan R.; Casey, John Patrick; Brown, Earlene D.; Oneyma, Ezenwa; Donaghy, Kelley J.

    2006-01-01

    A synthesis is developed to make biodiesel from vegetable oils such as soybean, sunflower, and corn oil, as an exercise in the laboratory. Viscosity measurements were used to gain an understanding of an intermolecular property of the biodiesel and that has limited the implementation of biodiesel on a wide scale basis, solidification at low…

  5. A Guide for Planning Facilities for Occupational Preparation Programs in Laboratory Animal Science Technology. Interim Report. Research 27.

    ERIC Educational Resources Information Center

    Colling, Walter E.; Farnsworth, Wilbur M.

    The major purpose of this guide is to elicit the necessary information for the writing of educational specifications for facilities to house career programs in laboratory animal science technology. The guide is also designed to: (1) assist planners in formation of creative solutions to the housing of desired educational programs, (2) prevent…

  6. Structural characterization, thermoluminescence and EPR studies of Nd{sub 2}O{sub 3}:Co{sup 2+} nanophosphors

    SciTech Connect

    Umesh, B.; Eraiah, B.; Nagabhushana, H.; Sharma, S.C.; Sunitha, D.V.; Nagabhushana, B.M.; Rao, J.L.; Shivakumara, C.; Chakradhar, R.P.S.

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► Nd{sub 2}O{sub 3}:Co{sup 2+} (1–4 mol%) nanophosphors have been prepared at much lower temperatures. ► Phosphors are well characterized by PXRD, SEM, TEM, FTIR, Raman, UV–vis spectroscopy. ► EPR and thermoluminescence properties were also reported. ► TL intensity increases linearly with γ dose suggesting usage in radiation dosimetry. -- Abstract: Nd{sub 2}O{sub 3}:Co{sup 2+} (1–4 mol%) nanophosphors (15–25 nm) have been prepared via low temperature solution combustion method. Scanning electron micrograph (SEM) shows that the product is highly porous in nature. The stokes line in the Raman spectrum at ∼2000 cm{sup −1} is assigned to F{sub g} mode and the anti-stokes lines are assigned to a combination of A{sub g} + E{sub g} modes. With increase of Co{sup 2+} concentration, the intensity of F{sub g} mode decreases, whereas the combination of A{sub g} + F{sub g} modes completely disappears. Electron paramagnetic resonance (EPR) spectrum exhibits two resonance signals with effective g values at g = 2.25 and g = 2.03. Thermoluminescence (TL) response of Nd{sub 2}O{sub 3}:Co{sup 2+} nanopowders with γ dose 0.23–2.05 kGy was studied. The activation energy (E) and frequency factor (s) are estimated using Chen's glow peak shape method and obtained to be in the range 0.45–1.67 eV and 1.8 × 10{sup 4} to 4.0 × 10{sup 12} s{sup −1}, respectively. It is observed that the TL glow peak intensity at 430 K increases linearly with γ dose which is suitable for radiation dosimetry.

  7. Full spectrum and selected spectrum based chemometric methods for the simultaneous determination of Cinnarizine and Dimenhydrinate in laboratory prepared mixtures and pharmaceutical dosage form

    NASA Astrophysics Data System (ADS)

    Tawakkol, Shereen M.; El-Zeiny, Mohamed B.; Hemdan, A.

    2017-02-01

    Three chemometric methods namely, concentration residual augmented classical least squares (CRACLS), spectral residual augmented classical least squares (SRACLS) and partial least squares (PLS) were applied for the simultaneous quantitative determination of Cinnarizine and Dimenhydrinate in their binary mixtures. All techniques were applied with and without variable selection using genetic algorithm (GA) resulting in six models (CRACLS, GA-CRACLS, SRACLS, GA-SRACLS, PLS, GA-PLS). These models were applied for the simultaneous determination of the drugs in their laboratory prepared mixtures and pharmaceutical dosage form via handling their UV spectral data. It was found that GA based models are simpler and more robust than those built with the full spectral data. The proposed models were found to be simple, fast and require no preliminary separation steps; so they can be used for the routine analysis of this binary mixture in quality control laboratories.

  8. Preparation and certification of two new bulk welding fume reference materials for use in laboratories undertaking analysis of occupational hygiene samples.

    PubMed

    Butler, Owen; Musgrove, Darren; Stacey, Peter

    2014-01-01

    Workers can be exposed to fume, arising from welding activities, which contain toxic metals and metalloids. Occupational hygienists need to assess and ultimately minimize such exposure risks. The monitoring of the concentration of particles in workplace air is one assessment approach whereby fume, from representative welding activities, is sampled onto a filter and returned to a laboratory for analysis. Inductively coupled plasma-atomic emission spectrometry and inductively coupled plasma-mass spectrometry are generally employed as instrumental techniques of choice for the analysis of such filter samples. An inherent difficulty, however, with inductively coupled plasma-based analytical techniques is that they typically require a sample to be presented for analysis in the form of a solution. The efficiency of the required dissolution step relies heavily upon the skill and experience of the analyst involved. A useful tool in assessing the efficacy of this dissolution step would be the availability and subsequent analysis of welding fume reference materials with stated elemental concentrations and matrices that match as closely as possible the matrix composition of welding fume samples submitted to laboratories for analysis. This article describes work undertaken at the Health and Safety Laboratory to prepare and certify two new bulk welding fume reference materials that can be routinely used by analysts to assess the performance of the digestion procedures they employ in their laboratories.

  9. Preparation and Certification of Two New Bulk Welding Fume Reference Materials for Use in Laboratories Undertaking Analysis of Occupational Hygiene Samples

    PubMed Central

    Butler, Owen; Musgrove, Darren; Stacey, Peter

    2014-01-01

    Workers can be exposed to fume, arising from welding activities, which contain toxic metals and metalloids. Occupational hygienists need to assess and ultimately minimize such exposure risks. The monitoring of the concentration of particles in workplace air is one assessment approach whereby fume, from representative welding activities, is sampled onto a filter and returned to a laboratory for analysis. Inductively coupled plasma-atomic emission spectrometry and inductively coupled plasma-mass spectrometry are generally employed as instrumental techniques of choice for the analysis of such filter samples. An inherent difficulty, however, with inductively coupled plasma-based analytical techniques is that they typically require a sample to be presented for analysis in the form of a solution. The efficiency of the required dissolution step relies heavily upon the skill and experience of the analyst involved. A useful tool in assessing the efficacy of this dissolution step would be the availability and subsequent analysis of welding fume reference materials with stated elemental concentrations and matrices that match as closely as possible the matrix composition of welding fume samples submitted to laboratories for analysis. This article describes work undertaken at the Health and Safety Laboratory to prepare and certify two new bulk welding fume reference materials that can be routinely used by analysts to assess the performance of the digestion procedures they employ in their laboratories. PMID:24499055

  10. A microfluidic device for preparing next generation DNA sequencing libraries and for automating other laboratory protocols that require one or more column chromatography steps.

    PubMed

    Tan, Swee Jin; Phan, Huan; Gerry, Benjamin Michael; Kuhn, Alexandre; Hong, Lewis Zuocheng; Min Ong, Yao; Poon, Polly Suk Yean; Unger, Marc Alexander; Jones, Robert C; Quake, Stephen R; Burkholder, William F

    2013-01-01

    Library preparation for next-generation DNA sequencing (NGS) remains a key bottleneck in the sequencing process which can be relieved through improved automation and miniaturization. We describe a microfluidic device for automating laboratory protocols that require one or more column chromatography steps and demonstrate its utility for preparing Next Generation sequencing libraries for the Illumina and Ion Torrent platforms. Sixteen different libraries can be generated simultaneously with significantly reduced reagent cost and hands-on time compared to manual library preparation. Using an appropriate column matrix and buffers, size selection can be performed on-chip following end-repair, dA tailing, and linker ligation, so that the libraries eluted from the chip are ready for sequencing. The core architecture of the device ensures uniform, reproducible column packing without user supervision and accommodates multiple routine protocol steps in any sequence, such as reagent mixing and incubation; column packing, loading, washing, elution, and regeneration; capture of eluted material for use as a substrate in a later step of the protocol; and removal of one column matrix so that two or more column matrices with different functional properties can be used in the same protocol. The microfluidic device is mounted on a plastic carrier so that reagents and products can be aliquoted and recovered using standard pipettors and liquid handling robots. The carrier-mounted device is operated using a benchtop controller that seals and operates the device with programmable temperature control, eliminating any requirement for the user to manually attach tubing or connectors. In addition to NGS library preparation, the device and controller are suitable for automating other time-consuming and error-prone laboratory protocols requiring column chromatography steps, such as chromatin immunoprecipitation.

  11. Suppression of lysophosphatidic acid and lysophosphatidylcholine formation in the plasma in vitro: proposal of a plasma sample preparation method for laboratory testing of these lipids.

    PubMed

    Nakamura, Kazuhiro; Kishimoto, Tatsuya; Ohkawa, Ryunosuke; Okubo, Shigeo; Tozuka, Minoru; Yokota, Hiromitsu; Ikeda, Hitoshi; Ohshima, Noriko; Mizuno, Koji; Yatomi, Yutaka

    2007-08-01

    It is now established that lysophosphatidic acid (LPA) and lysophosphatidylcholine (LPC) play important roles in a variety of biological responses, especially in the area of vascular biology, and determination of their concentrations in the plasma is believed to be clinically relevant. Preparation of the measurement samples is a difficult task, however, because the blood levels of these lipids can be easily increased by in vitro manipulation after venepuncture. In this study, we examined the optimal conditions for the preparation of plasma samples for the measurement of LPA and LPC. It appears that regulation of platelet activation and the enzymatic activity of lysophospholipase D/autotaxin and lecithin-cholesterol acyltransferase is important to suppress the undesirable formation of LPA and LPC after venepuncture. We found that in vitro formation of LPA and LPC was negligible when whole blood samples were mixed with 7.5 mM EDTA plus 10% (v/v) citrate-theophylline-adenosine-dipyridamole (CTAD) and when all of the procedures, including the plasma preparation and preservation until measurement, were performed at 4 degrees C. Thus, although the plasma levels of LPA and LPC can be easily altered, laboratory testing of these important bioactive lipids for clinical purposes may be conducted reliably if the samples are prepared under stringent conditions.

  12. Refining of Military Jet Fuels from Shale Oil. Volume I. Part II. Preparation of Laboratory-Scale Fuel Samples.

    DTIC Science & Technology

    1982-03-01

    Sulfide Hydrog . Hydrogenated xix t ABBREVIATIONS (CONT’D) IBP initial Boiling Point 1.0. inside Diameter in Inches JP-4 military Specification MIL-T...were prepared in addition to a combined JP-4/JP-8 type of fuel. These samples were provided with a range of aromatics content and freeze point...slate of fuels shall include motor gasoline , aviation turbine fuels (grade JP-4 or JP-8 and grade JP-5), diesel fuel, diesel fuel marine and residual

  13. Salting-out assisted liquid/liquid extraction with acetonitrile: a new high throughput sample preparation technique for good laboratory practice bioanalysis using liquid chromatography-mass spectrometry.

    PubMed

    Zhang, Jun; Wu, Huaiqin; Kim, Elaine; El-Shourbagy, Tawakol A

    2009-04-01

    Acetonitrile, an organic solvent miscible with aqueous phase, has seen thousands of publications in the literature as an efficient deproteinization reagent. The use of acetonitrile for liquid-liquid extraction (LLE), however, has seen very limited application due to its miscibility with aqueous phase. The interest in LLE with acetonitrile has been pursued and reported in the literature by significantly lowering the temperature of the mixture or increasing the salt concentration in the mixture of acetonitrile and aqueous phase, resulting in the separation of the acetonitrile phase from aqueous phase, as observed in conventional LLE. However, very limited application of these methods has been reported. The throughput was limited. In this report, we report a new sample preparation technique, salting-out assisted liquid-liquid extraction with acetonitrile, for high-throughput good laboratory practice sample analysis using LCMS, Two compounds from an approved drug, Kaletra, were used to demonstrate the extractability of drugs from human plasma matrix. Magnesium sulfate was used as the salting-out reagent. Extracts were diluted and then injected into a reversed phase LC-MS/MS system directly. One 96-well plate was extracted with this new approach to evaluate multiple parameters of a good laboratory practice analytical method. Results indicate that the method is rapid, reliable and suitable for regulated bioanalysis. With minimal modification, this approach has been used for high-throughput good laboratory practice analysis of a number of compounds under development at Abbott.

  14. Influence of nitrogen implantation on thermoluminescence of synthetic quartz

    NASA Astrophysics Data System (ADS)

    Nsengiyumva, S.; Chithambo, M. L.; Pichon, L.

    2014-11-01

    Thermoluminescence (TL) of synthetic quartz exposed to beta irradiation following implantation with 60 keV N+ ions at fluences ranging between 1 × 1014 and 5 × 1015 ions/cm2 is reported. The glow curve measured at 5°C/s typically consists of a prominent peak near 110°C, studied in this work, and minor glow peaks at around 130°C and 190°C. The TL intensity of the main peak increased both with implantation and with fluence of implantation. The dependence of the intensity on heating rate and fluence suggests that the implantation introduces new defects that may possibly act as recombination centres. The increase in TL intensity with the heating rate exhibited by implanted samples has been observed in other luminescence materials. This anti-quenching phenomenon has been described as a competition effect between multiple luminescence pathways in luminescence materials. Kinetic analysis of the main glow peak using the initial rise, various heating rate and glow curve deconvolution methods shows that the activation energy of the main peak is about 0.7 eV with no systematic change due to ion fluence.

  15. Influence of nitrogen implantation on thermoluminescence of synthetic quartz

    NASA Astrophysics Data System (ADS)

    Nsengiyumva, S.; Chithambo, M. L.; Pichon, L.

    2015-01-01

    Thermoluminescence (TL) of synthetic quartz exposed to beta irradiation following implantation with 60 keV N+ ions at fluences ranging between 1 × 1014 and 5 × 1015 ions/cm2 is reported. The glow curve measured at 5°C/s typically consists of a prominent peak near 110°C, studied in this work, and minor glow peaks at around 130°C and 190°C. The TL intensity of the main peak increased both with implantation and with fluence of implantation. The dependence of the intensity on the heating rate and fluence suggests that the implantation introduces new defects that may possibly act as recombination centres. The increase in TL intensity with the heating rate exhibited by implanted samples has been observed in other luminescence materials. This anti-quenching phenomenon has been described as a competition effect between multiple luminescence pathways in luminescence materials. Kinetic analysis of the main glow peak using the initial rise, various heating rate and glow-curve deconvolution methods shows that the activation energy of the main peak is about 0.7 eV with no systematic change due to ion fluence.

  16. Accelerator room photoneutron and photon background measurements using thermoluminescent dosimeters.

    PubMed

    Anderson, D W; Hwang, C C

    1983-02-01

    Photoneutron dose equivalents and photon doses in the treatment room of a clinical linear accelerator were measured with sets of isotopically enriched LiF thermoluminescent dosimeters and a moderating sphere. Dosimeter neutron calibrations with 252Cf sources were repeated many times during the extended series of measurements because the 6LiF dosimeter sensitivity increased with successive neutron irradiations. Expressed as a fraction of the primary bremsstrahlung beam dose at maximum, the photoneutron background was 2.04 +/- 0.05 mrem/rad (10(-3) Sv/Gy) at 1 m lateral to beam center in the patient midplane at 25 MV. The fraction of this result due to thermal neutrons was found to be only about 2%. The photon background dose was 2.98 +/- 0.04 mrad/rad (10(-3) Gy/Gy). The photoneutron dose equivalent per unit primary dose was found to be nearly independent of the collimator size used but increased by 40% when the bremsstrahlung endpoint energy was increased from 20 to 35 MeV with no change in flattening filters.

  17. Thermoluminescence dating of the Kamil impact crater (Egypt)

    NASA Astrophysics Data System (ADS)

    Sighinolfi, Gian Paolo; Sibilia, Emanuela; Contini, Gabriele; Martini, Marco

    2015-02-01

    Thermoluminescence (TL) dating has been used to determine the age of the meteorite impact crater at Gebel Kamil (Egyptian Sahara). Previous studies suggested that the 45 m diameter structure was produced by a fall in recent times (less than 5000 years ago) of an iron meteorite impactor into quartz-arenites and siltstones belonging to the Lower Cretaceous Gilf Kebir Formation. The impact caused the complete fragmentation of the impactor, and the formation of a variety of impactites (e.g., partially vitrified dark and light materials) present as ejecta within the crater and in the surrounding area. After a series of tests to evaluate the TL properties of different materials including shocked intra-crater target rocks and different types of ejecta, we selected a suite of light-colored ejecta that showed evidence of strong thermal shock effects (e.g., partial vitrification and the presence of high-temperature and -pressure silica phases). The abundance of quartz in the target rocks, including the vitrified impactites, allowed TL dating to be undertaken. The variability of radioactivity of the intracrateric target rocks and the lack of direct in situ dosimetric evaluations prevented precise dating; it was, however, possible to constrain the impact in the 2000 BC-500 AD range. If, as we believe, the radioactivity measured in the fallback deposits is a reliable estimate of the mean radioactivity of the site, the narrower range 1600-400 BC (at the 2σ confidence level) can be realistically proposed.

  18. tgcd: An R package for analyzing thermoluminescence glow curves

    NASA Astrophysics Data System (ADS)

    Peng, Jun; Dong, ZhiBao; Han, FengQing

    Thermoluminescence (TL) glow curves are widely used in dosimetric studies. Many commercial and free-distributed programs are used to deconvolute TL glow curves. This study introduces an open-source R package tgcd to conduct TL glow curve analysis, such as kinetic parameter estimation, glow peak simulation, and peak shape analysis. TL glow curves can be deconvoluted according to the general-order empirical expression or the semi-analytical expression derived from the one trap-one recombination center (OTOR) model based on the Lambert W function by using a modified Levenberg-Marquardt algorithm from which any of the parameters can be constrained or fixed. The package provides an interactive environment to initialize parameters and offers an automated "trial-and-error" protocol to obtain optimal fit results. First-order, second-order, and general-order glow peaks (curves) are simulated according to a number of simple kinetic models. The package was developed using a combination of Fortran and R programming languages to improve efficiency and flexibility.

  19. CVD diamonds as thermoluminescent detectors for medical applications.

    PubMed

    Marczewska, B; Olko, P; Nesladek, M; Waligórski, M P R; Kerremans, Y

    2002-01-01

    Diamond is believed to be a promising material for medical dosimetry due to its tissue equivalence, mechanical and radiation hardness, and lack of solubility in water or in disinfecting agents. A number of diamond samples, obtained under different growth conditions at Limburg University, using the chemical vapour deposition (CVD) technique, was tested as thermoluminescence dosemeters. Their TL glow curve, TL response after doses of gamma rays, fading, and so on were studied at dose levels and for radiation modalities typical for radiotherapy. The investigated CVD diamonds displayed sensitivity comparable with that of MTS-N (Li:Mg,Ti) detectors, signal stability (reproducibility after several readouts) below 10% (1 SD) and no fading was found four days after irradiation. A dedicated CVD diamond plate was grown, cut into 20 detector chips (3 x 3 x 0.5 mm) and used for measuring the dose-depth distribution at different depths in a water phantom, for 60Co and six MV X ray radiotherapy beams. Due to the sensitivity of diamond to ambient light, it was difficult to achieve reproducibility comparable with that of standard LiF detectors.

  20. Production of element correction factors for thermoluminescent dosimeters

    SciTech Connect

    Plato, P.; Miklos, J.

    1985-11-01

    Approximately 80 processors of personal dosimetry in the United States use thermoluminescent dosimeters (TLDs). Recent demands that dosimetry processors be able to measure radiation doses to within +/- 50% of the correct value have focused attention on the reproducibility of the TL elements within each TLD. The phosphors for these TLDs are manufactured by three companies. A dosimetry processor faces three options concerning the quality of the TL elements purchased; trust the supplier's quality control program, screen new TL elements and discard those that are extremely bad, or use element correction factors (ECFs). The first option results in dosimetry processors failing the +/- 50% accuracy requirement due to excessive variability among the TL elements. The second option still permits large precision errors that come close to the +/- 50% accuracy requirement. This paper advocates the third option and presents a 10-step procedure to produce ECFs. The procedure ensures that the ECFs represent only variations among the TL elements and not variations caused by stability problems with the TLD reader. Following is an example of ECF production for 3000 TLDs.

  1. Thermoluminescence response of natural white quartz collected from Gelephu, Bhutan

    NASA Astrophysics Data System (ADS)

    Kalita, J. M.; Wary, G.

    2016-09-01

    TL properties of natural quartz mineral collected from Gelephu, (Bhutan) were studied. With the help of various characterization techniques the quality of the sample was tested. The thermoluminescence (TL) analysis was carried out under X-ray irradiation. The un-irradiated sample showed no TL signal; however, after X-ray irradiation, a composite glow curve was observed. The kinetic analysis of the glow curve was carried out and it was observed that there was five trapping sites at depths ∼0.68, 0.90, 0.97, 1.06 and 1.10 eV responsible for five closely spaced glow peaks at ∼341, 362, 383, 397 and 426 K respectively. The dosimetric features of the mineral were studied. The response when studied from the whole glow curve was non-linear. However, the dose response studied from the 426 K peak was found to be linear from 10 mGy to 10 Gy. The fading of the TL signal of this 426 K peak was ∼12% within 5 days after irradiation and onward it was ∼4% up to 30 days. The reproducibility of the results was also good.

  2. Thermoluminescence dosimetry measurements of brachytherapy sources in liquid water

    SciTech Connect

    Tailor, Ramesh; Tolani, Naresh; Ibbott, Geoffrey S.

    2008-09-15

    Radiation therapy dose measurements are customarily performed in liquid water. The characterization of brachytherapy sources is, however, generally based on measurements made with thermoluminescence dosimeters (TLDs), for which contact with water may lead to erroneous readings. Consequently, most dosimetry parameters reported in the literature have been based on measurements in water-equivalent plastics, such as Solid Water. These previous reports employed a correction factor to transfer the dose measurements from a plastic phantom to liquid water. The correction factor most often was based on Monte Carlo calculations. The process of measuring in a water-equivalent plastic phantom whose exact composition may be different from published specifications, then correcting the results to a water medium leads to increased uncertainty in the results. A system has been designed to enable measurements with TLDs in liquid water. This system, which includes jigs to support water-tight capsules of lithium fluoride in configurations suitable for measuring several dosimetric parameters, was used to determine the correction factor from water-equivalent plastic to water. Measurements of several {sup 125}I and {sup 131}Cs prostate brachytherapy sources in liquid water and in a Solid Water phantom demonstrated a correction factor of 1.039{+-}0.005 at 1 cm distance. These measurements are in good agreement with a published value of this correction factor for an {sup 125}I source.

  3. The Orbits of Meteorites from Natural Thermoluminescence. Attachment 5

    NASA Technical Reports Server (NTRS)

    Benoit, P. H.; Sears, D. W. G.

    1997-01-01

    The natural thermoluminescence (TL) of meteorites reflects their irradiation and thermal histories. Virtually all ordinary chondrites have been irradiated long enough to reach saturation natural TL levels, and thus natural TL levels in these meteorites are determined largely by thermal history. The primary heat source for most meteorites is the Sun, and thus natural TL levels are determined primarily by the closest approach to the Sun, i.e., perihelion. By converting natural TL levels to perihelia, using an assumed albedo typical of meteoroid bodies, it is found that most ordinary chondrites had perihelia of 0.85 to 1.0 AU prior to reaching Earth. This range is similar to that calculated from meteor and fireball observations. All common classes of ordinary chondrites exhibit similar perihelia distributions; however, H and LL chondrites that fell in the local morning differ in their natural TL distribution from those that fell in the local afternoon or evening. This is consistent with earlier suggestions that time of fall reflects orbital distribution. The data also suggest that the orbits of some of the H chondrites cluster and may have come from a debris 'stream' of meteoroids. If meteorites can exist in "orbital groups," significant changes in the types and number of meteorites reaching Earth could occur on the less than 10(exp 5)-year time scale.

  4. Thermoluminescence of mercaptoethanol-capped ZnS:Mn nanoparticles.

    PubMed

    Sharma, Ravi; Bisen, D P

    2015-03-01

    The thermoluminescence (TL) of nanoparticles has become a matter of keen interest in recent times but is rarely reported. This article reports the synthesis of ZnS:Mn nanocrystals using a chemical route, with mercaptoethanol (ME) as the capping agent. The particle sizes for the nanocrystals were measured by X-ray diffraction (XRD) and also by studying transmission electron microscopy (TEM) patterns. The particle sizes of the synthesized samples were found to be between 1 and 3 nm. For samples with different concentrations of the capping agent, it was found that the TL intensity of the ZnS:Mn nanoparticles increased as the particle size decreased. A shift in the peak position of the TL glow curve was also seen with decreasing particle size. The TL intensity was found to be maximal for samples with 1.2% of Mn. A change in the peak position was not found for samples with different concentrations of Mn. The half-width glow peak curve method was used to determine the trap-depth. The frequency factor of the synthesized samples was also calculated. The stability of the charge carriers in the traps increases with decreasing nanoparticle size. The higher stability may be attributed to the higher surface/volume ratio and also to the increase in the trap-depth with decreasing particle size.

  5. Thermoluminescence glow curve analysis of natural onyx from Turkey.

    PubMed

    Dogan, Tamer; Toktamış, Hüseyin; Yüksel, Mehmet; Topaksu, Mustafa; Yazici, A Necmeddin

    2015-02-01

    In this study, the thermoluminesce (TL) properties of natural onyx were determined after β-irradiation ((90)Sr/(90)Y) at room temperature. The effect of the additive dose and variable heating rate for TL glow peaks of the sample were investigated. Computerized glow curve deconvolution (CGCD) methods were used to determine the number of peaks and kinetic parameters related to the TL glow peaks in natural onyx from Turkey. It was also determined kinetic parameters of onyx by means of the variable heating rate (VHR) method. The sample was exposed to β-irradiation between 2.4 Gy and 2.457 kGy. The CGCD methods showed that the glow curve of sample is the superposition of at least six first order components which were ascribed as P1-P6. The dose responses of some peaks have similar patterns and they follow linearity. The effect of heating rates on the response of dosimetric glow peaks of sample was studied. The maximum TL peak intensities of glow curve are decreasing with increasing heating rate and maximum TL peak intensities at 1 °C/s drops to 20% of the initial value when the sample is read at 6 °C/s.

  6. Analysis of Thermoluminescence Glow Curves Using Derivatives of Different Orders.

    PubMed

    Karmakar, Mahua; Bhattacharyya, S; Sarkar, A; Mazumdar, P S; Singh, S D

    2017-01-16

    The suitability of the second derivative method for locating component peaks in complex thermoluminescence (TL) glow curves has been investigated in this work by considering both numerically simulated and experimental TL peaks. This technique is useful to acquire knowledge of the number of component peaks in a complex TL curve which in turn serves as a basic information before applying the deconvolution technique to the glow curve. To check the consistency of the results so obtained, we have also applied the first derivative technique to TL glow curves. It is well-known that kinetic order formalism fails for saturated TL peaks with heavy retrapping. Such peaks are usually broad and, to the best of our knowledge, have not yet been observed experimentally. The present derivative technique has been used to detect whether such broad peaks are truly single or not by considering a number of numerically simulated saturated glow curves with heavy retrapping where the conventional peak shape method fails. In all the cases considered here, the second derivative technique proves to be a potential candidate for estimating the number of peaks and their respective locations in a complex TL glow curve.

  7. Analysis of thermoluminescent glow peaks of zoisite under beta irradiations

    SciTech Connect

    Ccallata, Henry Javier; Watanabe, Shigueo

    2010-08-04

    In this study, the thermoluminescence (TL) properties of natural crystal of zoisite were investigated after beta ({sup 90}Sr) irradiation at room temperature (RT). Zoisite, of chemical formula Ca{sub 2}Al{sub 3}(SiO{sub 4})(Si{sub 2}O{sub 7})O(OH), is found in Minas Gerais State, Brazil as natural mineral of silicate, member of the epidote group. The glow curve of a natural sample submitted to a heat treatment at 600 deg. C is composed of two broad peaks, centered at about 110-130 deg. C and another one at about 205-210 deg. C. A heating rate of 4 deg. C s{sup -1} was used in the temperature range from RT to 300 deg. C. The additive dose, T{sub m}-T{sub STOP} thermal cleaning, initial rise, variable heating rate and computerized glow curve deconvolution methods have shown that the glow curve is a superposition of six peaks at 100, 130, 155, 175, 200 and 230 deg. C. The trapping parameters for the individual peaks have been calculated. The TL dose response of 130 and 200 deg. C peaks has a linear response. Zoisite is a candidate for a TL dosimeter because of its high sensitivity.

  8. Thermoluminescence signal in K-feldspar grains: Revisited.

    PubMed

    Gong, Gelian; Sun, Weidong; Xu, Hongyun

    2015-11-01

    Recent work has shown that infrared stimulated luminescence (IRSL) signals in sedimentary coarse-grain K-feldspars are derived mainly from high temperature thermoluminescence (TL) peaks around 400°C, and the fading components of the IRSL signal can be preferentially removed by prior IR stimulation at relatively low temperature. Considering the complexity of TL signal for very old samples, we may choose non-fading components from K-feldspar TL signals using the combination of optical and thermal activation methods. This paper examines a protocol of post-IR isothermal TL (i.e. pIRITL) signal for sedimentary coarse-grain K-feldspars, which results from isothermal TL measurements following elevated temperature IR bleaching. We show that a sum of two exponential decay functions can fit well to the pIRITL decay curves, and both the holding temperature for isothermal TL measurements and the prior elevated temperature IR bleaching can affect greatly the fast components of pIRITL signal. The dose response ranges of pIRITL signal are wider than those of post-IR IRSL signals, but the relative high residual pIRITL signal means that it is not appropriate for dating young samples. It is expected that one isothermal TL signal for K-feldspar measured at ~400°C following IR bleaching at 290°C (i.e. pIRITL400) is useful for dating very old samples.

  9. Thermoluminescence properties of annealed natural quartz after beta irradiation.

    PubMed

    Yüksel, Mehmet; Dogan, Tamer; Unsal, Emre; Portakal, Z Gizem; Akca, Sibel; Yegingil, Zehra; Topaksu, Mustafa

    2016-12-01

    Here we investigated the effects of annealing, heating rate and fading (after annealing at 800 °C) on the thermoluminescence (TL) glow curves of natural quartz (NQ). All of the samples were annealed at different temperatures between 100 °C and 800 °C and then irradiated with a beta dose of about 34 Gray (Gy), in order to determine the effects of annealing treatments on TL peaks of natural quartz. TL glow curves of the samples were recorded. It was observed that the intensities of TL peaks were strongly sensitive to annealing temperatures at 800 °C. The heating rate and fading effect of TL peaks of natural quartz were examined for the annealed samples at 800 °C for 30 min. It was observed that the intensities of the TL peaks were differently affected from heating rate and fading. Additionally, TL kinetic parameters (activation energy, frequency factor and order of kinetics) of all peaks were determined for annealed samples using a computerized glow curve deconvolution (CGCD) method and Mathematica software. Copyright © 2016 John Wiley & Sons, Ltd.

  10. Dose measurements in intraoral radiography using thermoluminescent dosimeters

    NASA Astrophysics Data System (ADS)

    Azorín, C.; Azorín, J.; Aguirre, F.; Rivera, T.

    2015-01-01

    The use of X-ray in medicine demands to expose the patient and the professional to the lowest radiation doses available in agreement with ALARA philosophy. The reference level for intraoral dental radiography is 7 mGy and, in Mexico, a number of examinations of this type are performed annually. It is considered that approximately 25% of all the X-rays examinations carried out in our country correspond to intraoral radiographies. In other hand, most of the intraoral X-ray equipment correspond to conventional radiological systems using film, which are developed as much manual as automatically. In this work the results of determining the doses received by the patients in intraoral radiological examinations made with different radiological systems using LiF:Mg,Cu,P+PTFE thermoluminescent dosimeters are presented. In some conventional radiological systems using film, when films are developed manual or automatically, incident kerma up to 10.61 ± 0.74 mGv were determined. These values exceed that reference level suggested by the IAEA and in the Mexican standards for intraoral examinations.

  11. The effects of high ambient radon on thermoluminescence dosimetry readings.

    PubMed

    Harvey, John A; Kearfott, Kimberlee J

    2011-11-01

    The effect of a high level of ambient (222)Rn gas on thermoluminescence dosemeters (TLDs) is examined. Groups of LiF:Mg,Ti and CaF(2):Dy TLDs were exposed to (222)Rn under controlled environmental conditions over ∼7 d using a luminous (226)Ra aircraft dial. LiF:Mg,Ti TLDs were tested bare, and both types were tested mounted in cards used for environmental dosimetry and mounted in cards enclosed in plastic badges. A passive continuous radon monitor was used to measure the (222)Rn level in the small chamber during the experiments. The data were analysed to determine the relationship between the integrated (222)Rn level and the TLD response. Although both LiF:Mg,Ti and CaF(2):Dy TLDs showed a strong response to (222)Rn, the badges prevented measurable radon detection by the TLDs within. The TLDs were not used to directly measure the radon concentration; rather, a correction for its influence was desired.

  12. Preparation of the First Shipment of Transuranic Waste by the Los Alamos National Laboratory: A Rest Stop on the Road to WIPP

    SciTech Connect

    Allen, G.; Barr, A.; Betts, S.E.; Farr, J.; Foxx, J.; Gavett, M.A.; Janecky, D.R.; Kosiewicz, S.T.; Liebman, C.P.; Montoya, A.; Poths, H.; Rogers, P.S.Z.; Taggart, D.P.; Triay, I.R.; Vigil, G.I.; Vigil, J.J.; Wander, S.G.; Yeamans, D.

    1999-02-01

    The Los Alamos National Laboratory (LANL) achieved a national milestone on the road to shipping transuranic (TRU) waste to the Waste Isolation Pilot Plant (WIPP) when it received certification authority on September 12, 1997. Since that time, LANL has been characterizing a non-mixed TRU waste stream and preparing shipments of this TRU waste for disposal in the WIPP. The paper describes the TRU waste identified as waste stream TA-55-43 Lot No. 01 from LANL Technical Area-55 and the process used to determine that it does not contain hazardous waste regulated by the Resource Conservation Recovery Act (RCRA) or the New Mexico Hazardous Waste Act (HWA). The non-mixed determination is based on the acceptable knowledge (AK) characterization process, which clearly shows that the waste does not exhibit any RCRA characteristics nor meet any RCRA listing descriptions. LANL has certified TRU waste from waste stream TA-55-43 Lot No. 01 and is prepared to certify additional quantities of TRU waste horn other non-mixed TRU waste streams. Assembly and preparation of AK on the processes that generated TRU waste is recognized as a necessary part of the process for having waste ready for shipment to the WIPP.

  13. Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Polyethylene Reflected Pulse of the CEA Valduc SILENE Critical Assembly

    SciTech Connect

    Miller, Thomas Martin; Celik, Cihangir; McMahan, Kimberly L.; Lee, Yi-kang; Gagnier, Emmanuel; Authier, Nicolas; Piot, Jerome; Jacquet, Xavier; Rousseau, Guillaume; Reynolds, Kevin H.

    2016-09-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 19, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube and the Rocky Flats detects neutrons via charged particles produced in a thin 6LiF disc depositing energy in a Si solid state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  14. Neutron Activation and Thermoluminescent Detector Responses to a Bare Pulse of the CEA Valduc SILENE Critical Assembly

    SciTech Connect

    Miller, Thomas Martin; Celik, Cihangir; McMahan, Kimberly L.; Lee, Yi-kang; Gagnier, Emmanuel; Authier, Nicolas; Piot, Jerome; Jacquet, Xavier; Rousseau, Guillaume; Reynolds, Kevin H.

    2016-09-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 11, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  15. Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Lead Reflected Pulse of the CEA Valduc SILENE Critical Assembly

    SciTech Connect

    Miller, Thomas Martin; Celik, Cihangir; Isbell, Kimberly McMahan; Lee, Yi-kang; Gagnier, Emmanuel; Authier, Nicolas; Piot, Jerome; Jacquet, Xavier; Rousseau, Guillaume; Reynolds, Kevin H.

    2016-09-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 13, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube, and the Rocky Flats detects neutrons via charged particles produced in a thin 6LiF disc, depositing energy in a Si solid-state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  16. Influence of argon-implantation on conventional and phototransferred thermoluminescence of synthetic quartz

    NASA Astrophysics Data System (ADS)

    Nsengiyumva, S.; Chithambo, M. L.; Pichon, L.

    2016-03-01

    Conventional and phototransferred thermoluminescence of crystalline synthetic quartz implanted with 70 keV Ar ions at fluences in the range 1 × 1014-5 × 1015 ions/cm2 is reported. The glow curves, recorded at 5°C/s from beta-irradiated samples of similar mass, show a prominent peak between 100°C and 120°C. The thermoluminescence intensity of all implanted samples was greater than that of the unimplanted one. The increase in sensitivity is attributed to a corresponding increase in the concentration of point defects, as a result of the implantation, which act as electron traps or recombination centres. Kinetic analysis carried out using the peak shape, whole glow-peak and curve-fitting methods produced values of the activation energy, frequency factor and order of kinetics that are generally independent of implantation fluence. This result suggests that implantation did not necessarily affect the nature of the electron traps. With respect to phototransferred thermoluminescence, it was observed that it only appeared in the sample implanted at the highest fluence of 5 × 1015 ions/cm2. This may be so because the concentration of deep traps produced as a result of implantation at low fluence is too low to give rise to phototransferred thermoluminescence. The intensity of the phototransferred thermoluminescence goes through a peak with illumination time. We attribute this behaviour to the relative concentration of holes at recombination centres and phototransferred electrons at shallow traps.

  17. Influence of γ-dose, dopant/codopant and heating rate on thermoluminescence properties of CaWO{sub 4} phosphors

    SciTech Connect

    Ambast, A. K. Sharma, S. K.

    2015-08-28

    A series of Ca{sub 1-2x}K{sub x}Dy{sub x}WO{sub 4} (x = 0.02, 0.03, 0.04) phosphors were prepared by solid state reaction method and their thermoluminescence properties were investigated. Before thermoluminescence measurements, the sample was heated to 300°C for 1hour and then quenched to room temperature to erase out all the previous radiation memory. The prepared phosphors were irradiated by γ-ray in the dose range 1KGy–5KGy and their glow curves were recorded at an uniform rate of 5°C/s. In order to see the effect of heating rate as well as concentration of dopant/codopant, TL glow curves were also recorded by heating the samples at the rate of 3°C/s and 7°C/s as well as by varying the concentration x = 0.02, 0.03, 0.04.

  18. Report on Department of Homeland Security Sponsored Research Project at Lawrence Livermore National Laboratory on Preparation for an Improvised Nuclear Device Event

    SciTech Connect

    A., B

    2008-07-31

    Following the events of September 11th, a litany of imaginable horribles was trotted out before an anxious and concerned public. To date, government agencies and academics are still grappling with how to best respond to such catastrophes, and as Senator Lieberman's quote says above, now is the time to plan and prepare for such events. One of the nation's worst fears is that terrorists might detonate an improvised nuclear device (IND) in an American city. With 9/11 serving as the catalyst, the government and many NGOs have invested money into research and development of response capabilities throughout the country. Yet, there is still much to learn about how to best respond to an IND event. My summer 2008 internship at Lawrence Livermore National Laboratory afforded me the opportunity to look in depth at the preparedness process and the research that has been conducted on this issue. While at the laboratory I was tasked to collect, combine, and process research on how cities and the federal government can best prepare for the horrific prospect of an IND event. Specific projects that I was involved with were meeting reports, research reviews, and a full project report. Working directly with Brooke Buddemeier and his support team at the National Atmospheric Release Advisory Center, I was able to witness first hand, preparation for meetings with response planners to inform them of the challenges that an IND event would pose to the affected communities. In addition, I supported the Homeland Security Institute team (HSI), which was looking at IND preparation and preparing a Congressional report. I participated in meetings at which local responders expressed their concerns and contributed valuable information to the response plan. I specialized in the psycho-social aspects of an IND event and served as a technical advisor to some of the research groups. Alongside attending and supporting these meetings, I worked on an independent research project which collected

  19. Thermoluminescence characteristics of Zn(BO2)2:Ce3+ under beta irradiation.

    PubMed

    Kucuk, Nil; Kucuk, Ilker; Yüksel, Mehmet; Topaksu, Mustafa

    2016-03-01

    In this study, the thermoluminescence (TL) characteristics of undoped and various Ce(3) (+)-doped Zn(BO2)2 powder samples excited by beta irradiation are reported for the first time. Zn(BO2)2:Ce(3+) powder samples were prepared by the nitric acid method (NAM) using the starting oxides [zinc oxide (ZnO), boric acid (H3BO3) and doped element oxide (CeO2)]. The formations of the obtained samples were confirmed by an X-ray diffraction study. Dose responses of Ce(3) (+)-doped Zn(BO2)2 samples were investigated after the beta irradiation in the dose range from 143 mGy to 60 Gy. All TL measurements were made on using an automated Risø TL/OSL DA-20 reader. TL emission was detected through a filter pack (Schott BG-39 and Corning 7-59) transmitting between 330 and 480 nm. TL glow curves were obtained using a constant heating rate of 5°C s(-1) from room temperature (RT) to 450°C in an N2 atmosphere. The dose response and minimum detectable dose (MDD) values of the samples were determined. The dose responses of all the samples tested exhibited a superlinear behaviour. MDD value of 4 % Ce(3) (+)-doped Zn(BO2)2 sample, which shows a high temperature peak at about 230°C, was determined as 96 mGy. MDD values for 1, 2, 3, 5 and 10 % Ce(3) (+)-doped Zn(BO2)2 samples were also determined as 682, 501, 635, 320 and 824 mGy, respectively. The trap parameters of undoped and 4 % Ce(3) (+)-doped Zn(BO2)2 samples were estimated by the computerised glow curve deconvolution method.

  20. Thermoluminescence and nuclear particle tracks in ALHA-81005 Evidence for a brief transit time

    NASA Astrophysics Data System (ADS)

    Sutton, S. R.; Crozaz, G.

    1983-09-01

    Thermoluminescence and nuclear particle track measurements were made on the Antarctic meteorite ALHA-81005. No nuclear particle tracks were found in lithic fragments indicating that the clast material never resided at the very surface of the parent body. The unusually low natural thermoluminescence of this material is interpreted as being due to a combination of anomalous fading and thermal decay. The thermal decay could be due to very long terrestrial age or heating either during atmospheric entry, in a near sun orbit or during a parent body impact event. Impact heating is considered the more likely of these possibilities for this meteorite. If the impact heating interpretation is correct the thermoluminescence data constrains the space exposure time of the object to be less than 2,500 years. Such a brief earth transit time is consistent with a lunar origin for this meteorite.

  1. Change in thermoluminescence of irradiated paprika powder during storage under various temperature and humidity conditions

    NASA Astrophysics Data System (ADS)

    Kitai, Satoshi; Furuta, Masakazu

    2009-07-01

    The change in the thermoluminescence (TL) of mineral grains extracted from irradiated paprika powder was monitored for 6 months after irradiation. The samples were irradiated with 60Co gamma rays at doses of 1, 5, and 10 kGy and stored under various temperature and humidity conditions. It was found that 10-kGy irradiation was sufficient to achieve the decontamination level required by the Japanese Food Sanitation Law. A significant decrease in thermoluminescence was observed in the irradiated samples stored at high-temperatures and humidity conditions, conditions similar to real shipping conditions at countries where they are produced. The thermoluminescence method was found to be effective for the identification of samples irradiated with a dose of 10 kGy after 6 months of storage. However, samples irradiated with a dose of 1 kGy and stored under the same conditions could not be identified by this method.

  2. Synthesis and thermoluminescence of LaAlO3:Pr(3+) to UVC radiation dosimetry.

    PubMed

    Morales-Hernández, A; Zarate-Medina, J; Contreras-García, M E; Azorín-Nieto, J; Rivera-Montalvo, T

    2016-12-01

    Thermoluminescent (TL) response of trivalent praseodymium ion doped lanthanum aluminate (LaAlO3:Pr(3+)) obtained by Pechini method and Spray Dryer was studied. TL response of LaAlO3:Pr(3+) powders submitted at 1600°C exhibited one peak centered at 157°C. Sensitivity of LaAlO3:Pr(3+) was improved in around 90 times compared with undoped LaAlO3. TL response as a function of wavelength showed a maximum in 230nm. Dosimetric characteristics of LaAlO3:Pr(3+) under UVR radiation effects were analyzed. Evaluation of activation energy was obtained by Glow Fit v.1.3 software. Experimental results about thermoluminescent characteristics of LaAlO3:Pr(3+) suggest as good candidate to be employed as a complementary thermoluminescent device with other TL phosphors as aluminum oxide.

  3. Thermoluminescence properties of irradiated commercial color pencils for accidental retrospective dosimetry.

    PubMed

    Meriç, Niyazi; Şahiner, Eren; Bariş, Aytaç; Polymeris, George S

    2015-05-01

    Color pencils are widely used mostly in kindergartens, in schools and could be found in all houses with families having young children. Their wide spread use in modern times as well as their chemical composition, consisting mostly of Si and Al, constitute two strong motivations towards exploiting their use as accidental retrospective thermoluminescent dosimeters. The present manuscript reports on the study of colored pencils manufactured by a commercial brand in China which is very common throughout Turkey. The preliminary results discussed in the present work illustrated encouraging characteristics, such as the presence of a trapping level giving rise to natural TL in a temperature range that is sufficiently high. Specific thermoluminescence features of this peak, such as glow peak shape and analysis, anomalous fading, thermal quenching, reproducibility, linearity and recovery ability to low attributed doses were studied. The results suggest that the color pencils could be effectively used in the framework of retrospective thermoluminescent dosimetry with extreme caution, based on multiple aliquot protocols.

  4. Virtual Simulations as Preparation for Lab Exercises: Assessing Learning of Key Laboratory Skills in Microbiology and Improvement of Essential Non-Cognitive Skills

    PubMed Central

    Makransky, Guido; Thisgaard, Malene Warming; Gadegaard, Helen

    2016-01-01

    Objective To investigate if a virtual laboratory simulation (vLAB) could be used to replace a face to face tutorial (demonstration) to prepare students for a laboratory exercise in microbiology. Methods A total of 189 students who were participating in an undergraduate biology course were randomly selected into a vLAB or demonstration condition. In the vLAB condition students could use a vLAB at home to ‘practice’ streaking out bacteria on agar plates in a virtual environment. In the demonstration condition students were given a live demonstration from a lab tutor showing them how to streak out bacteria on agar plates. All students were blindly assessed on their ability to perform the streaking technique in the physical lab, and were administered a pre and post-test to determine their knowledge of microbiology, intrinsic motivation to study microbiology, and self-efficacy in the field of microbiology prior to, and after the experiment. Results The results showed that there were no significant differences between the two groups on their lab scores, and both groups had similar increases in knowledge of microbiology, intrinsic motivation to study microbiology, as well as self-efficacy in the field of microbiology. Conclusion Our data show that vLABs function just as well as face to face tutorials in preparing students for a physical lab activity in microbiology. The results imply that vLABs could be used instead of face to face tutorials, and a combination of virtual and physical lab exercises could be the future of science education. PMID:27253395

  5. Study of the thermoluminescence dosimetric properties of window glass

    NASA Astrophysics Data System (ADS)

    Engin, Birol; Aydaş, Canan; Demirtaş, Hayrünnisa

    2010-01-01

    This paper presents the main thermoluminescence (TL) dosimetric characteristics of commercial Turkish transparent window glass. The structure of the glow curves, including the number of peaks, was found to be dose-dependent. A low-temperature glow peak that at 160 °C shifts to higher temperatures was also observed with increasing storage time at room temperature. This result suggests that this TL glow peak is actually made up of two or more overlapping peaks. These we have attributed to the glow peaks at lower temperatures, which decay faster than the ones at higher temperatures with storage time. The thermal fading of the window glass sample at room temperature showed a relatively sharp decay of about 60% occurring over a period of 28 days, after which the decay rate is small for a measured period of 250 days. In order to the improve the post-irradiation stability of the glow curve, the glass samples were heated after irradiation. To remove the unstable TL peaks responsible for the initial rapid fading, post-irradiation heating at 160 °C for 10 min was found to be the most suitable procedure. The dosimetric characteristics of the post-irradiation heated window glass examined in this study include fading, gamma photon dose-response, reproducibility, batch sensitivity, humidity influence, a dose-rate effect and photon energy response. Dose-response was found to be appropriate for dosimetry in the range 5 Gy to 10 kGy. The post-irradiation heating procedure did not affect the main dosimetric characteristics of the window glass samples. The results in this work suggest that the materials could, by using the TL technique, be a suitable candidate for alternative dose measurements in radiation processing, provided that a judicious choice of the post-irradiation heat temperature is made to minimize fading.

  6. Photoluminescence and thermoluminescence in SBN:Cr crystals

    NASA Astrophysics Data System (ADS)

    Gao, M.; Kapphan, S.; Pankrath, R.

    2000-12-01

    Cr doping in Strontium Barium Niobate (SBN) crystals is found to enhance the photorefractive response. Absorption bands around 650 nm and below 600 nm can be attributed to Cr in SBN crystals. In addition to XPS experimental results, the appearance of broad R line absorptions at low temperature confirms that most Cr ions are in the Cr3+ charge state in the SBN crystals. Luminescence bands around 765 nm were observed with different peak positions in nominally pure and in Cr-doped SBN crystals. The positions of the maxima in the excitation spectra in SBN:Cr, coinciding with the absorption bands, indicate that this emission band comes from the excitation of Cr3+ ions. Two thermoluminescence (TL) peaks are found in SBN:Cr and nominally pure SBN crystals: one at 88 K and the other around 220 K. The identical spectral distribution of the two TL bands points to the same recombination process following the liberation of two light-induced electron trapping centers: Nb4+ polarons and VIS-centers created at low temperatures. A model of the thermal recovery process involved is proposed. The thermal activation energy for the hopping motion of Nb4+ polarons is estimated to be 0.18±0.02 eV. For the VIS-centers, the thermal activation energy estimated from their decay dynamics to be 0.36±0.05 eV (Ming Gao, PhD thesis, University of Osnabrück, Germany, 1998), agrees with the activation energy value 0.30±0.05 eV determined from the TL process.

  7. Organic Laboratory Experiments.

    ERIC Educational Resources Information Center

    Smith, Sherrel

    1990-01-01

    Detailed is a method in which short pieces of teflon tubing may be used for collection tubes for collecting preparative fractions from gas chromatographs. Material preparation, laboratory procedures, and results of this method are discussed. (CW)

  8. Thermoluminescence for nonlinear heating profiles with application to laser heated emissions

    SciTech Connect

    Lawless, John L.; Lo, D.

    2001-06-01

    A general formula is found to predict thermoluminescence emission over a wide range of heating profiles. This is particularly useful for rapid laser heating which generates very nonlinear temperature{endash}time profiles. Special cases of the general formula are considered for power-law and logarithmic temperature{endash}time curves. The results compare well to previous CO{sub 2} laser heated thermoluminescence experiments. The agreement between theory and experiment extends over several orders of magnitude change in the heating rate. {copyright} 2001 American Institute of Physics.

  9. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; preparation procedure for aquatic biological material determined for trace metals

    USGS Publications Warehouse

    Hoffman, Gerald L.

    1996-01-01

    A method for the chemical preparation of tissue samples that are subsequently analyzed for 22 trace metals is described. The tissue-preparation procedure was tested with three National Institute of Standards and Technology biological standard reference materials and two National Water Quality Laboratory homogenized biological materials. A low-temperature (85 degrees Celsius) nitric acid digestion followed by the careful addition of hydrogen peroxide (30-percent solution) is used to decompose the biological material. The solutions are evaporated to incipient dryness, reconstituted with 5 percent nitric acid, and filtered. After filtration the solutions were diluted to a known volume and analyzed by inductively coupled plasma-mass spectrometry (ICP-MS), inductively coupled plasma-atomic emission spectrometry (ICP-AES), and cold vapor-atomic absorption spectrophotometry (CV-AAS). Many of the metals were determined by both ICP-MS and ICP-AES. This report does not provide a detailed description of the instrumental procedures and conditions used with the three types of instrumentation for the quantitation of trace metals determined in this study. Statistical data regarding recovery, accuracy, and precision for individual trace metals determined in the biological material tested are summarized.

  10. Personnel-dosimetry intercomparison studies at the Oak Ridge National Laboratory

    SciTech Connect

    Swaja, R.E.; Sims, C.S.

    1982-01-01

    Since 1974, seven annual personnel dosimetry intercomparison studies have been conducted at the Oak Ridge National Laboratory using the Health Physics Reactor. These studies have produced more than 2000 measurements by 72 participating organizations of neutron and gamma dose equivalents between 0.1 to 15.0 mSv in six mixed radiation fields. The relative performance of three basic types of personnel neutron dosimeters (nuclear emulsion film, thermoluminescent, and track-etch) and two basic types of gamma dosimeters (film and thermoluminescent) was assessed based on experimental results obtained during the seven intercomparisons.

  11. Synthesis, photoluminescence and thermoluminescence properties of LiNa3P2O7:Tb3+ green emitting phosphor

    NASA Astrophysics Data System (ADS)

    Munirathnam, K.; Dillip, G. R.; Ramesh, B.; Joo, S. W.; Prasad Raju, B. Deva

    2015-11-01

    The alkaline phosphate based LiNa3P2O7:Tb3+ phosphors are prepared by solid state reaction method. X-ray diffraction (XRD) analysis shows that all the powders possess orthorhombic structure. Fourier transform infrared (FTIR) spectroscopy studies suggest that the phosphor belong to the diphosphate family. The morphology of the phosphors is identified by scanning electron microscopy (SEM). Upon 378 nm excitation, the LiNa3P2O7:Tb3+ phosphors shown emission bands at 482, 545, 588 and 620 nm corresponding to the transitions 5D4→7F6, 5D4→7F5, 5D4→7F4 and 5D4→7F3, respectively. The optimized concentration of Tb3+ in LiNa3P2O7 phosphor is found to be 9 mol%. The concentration quenching mechanism was proved to be the exchange interaction between two nearest Tb3+ ions with the critical distance (Rc) of 1.18 nm. The Commission International de l'Eclairage (CIE) coordinates evidence that the phosphors emit in the green light region. Thermoluminescence properties of the prepared phosphors are studied by pre-irradiating the powders with different doses of UV irradiation. The kinetic parameters of TL glow curves are calculated using Chen's peak shape method.

  12. Thermoluminescence and synchrotron radiation studies on the persistent luminescence of BaAl{sub 2}O{sub 4}:Eu{sup 2+},Dy{sup 3+}

    SciTech Connect

    Rodrigues, L.C.V.; Stefani, R.; Brito, H.F.; Felinto, M.C.F.C.; Hoelsae, J.; Lastusaari, M.; Laamanen, T.; Malkamaeki, M.

    2010-10-15

    The persistent luminescence materials, barium aluminates doped with Eu{sup 2+} and Dy{sup 3+} (BaAl{sub 2}O{sub 4}:Eu{sup 2+},Dy{sup 3+}), were prepared with the combustion synthesis at temperatures between 400 and 600 {sup o}C as well as with the solid state reaction at 1500 {sup o}C. The concentrations of Eu{sup 2+}/Dy{sup 3+} (in mol% of the Ba amount) ranged from 0.1/0.1 to 1.0/3.0. The electronic and defect energy level structures were studied with thermoluminescence (TL) and synchrotron radiation (SR) spectroscopies: UV-VUV excitation and emission, as well as with X-ray absorption near-edge structure (XANES) methods. Theoretical calculations using the density functional theory (DFT) were carried out in order to compare with the experimental data. - Graphical abstract: BaAl{sub 2}O{sub 4}:Eu{sup 2+},Dy{sup 3+} phosphors: Thermoluminescence glow curve and synchrotron radiation spectra. Persistent luminescence photographs obtained after ceased UV irradiation.

  13. Role of hydroxide impurities in the thermoluminescent behavior of lithium fluoride

    NASA Technical Reports Server (NTRS)

    Stoebe, T. G.; Dewerd, L. A.

    1985-01-01

    The influence of OH ion impurities on thermoluminescent sensitivity and supralinearity in LiF:Mg, Ti is analyzed. Available evidence is shown to be consistant with the presence of Ti-OH and Mg-OH complexes. The track interaction model is used to explain the data, with competing centers decreasing sensitivity and supralinearity at high concentrations.

  14. Year 2000 compliance concerns with the ISA Thermoluminescent Dosimetry Data Processing (TL-DP) software system

    SciTech Connect

    Saviz, K.

    1998-05-26

    The year 2000 is rapidly approaching, and there is a good chance that computer systems that utilize two digit year dates will experience problems in retrieval of date information. The ISA Thermoluminescent Dosimetry Data Processing (TL-DP) software and computer system has been reviewed for Year 2000 compliance issues.

  15. The Orbital Distribution of Meteorites Based on High Temperature Thermoluminescence. 1; Theory and Modern Falls

    NASA Technical Reports Server (NTRS)

    Benoit, P. H.; Sears, D. W. G.

    2001-01-01

    Like 250 C Thermoluminescence (TL) data, 400 C TL levels of modern falls largely reflect solar heating, and thus perihelia. The 400 C data offers additional constraints on orbital information for ordinary chondrites. Additional information is contained in the original extended abstract.

  16. Preparation of a sewage sludge laboratory quality control material for butyltin compounds and their determination by isotope-dilution mass spectrometry.

    PubMed

    Zuliani, Tea; Milačič, Radmila; Ščančar, Janez

    2012-05-01

    The characterisation of a laboratory quality control material (QCM) for dibutyltin (DBT) and tributyltin (TBT) in sewage sludge is described. The reference values were determined by the use of two different types of isotope-dilution mass spectrometry: gas chromatography-mass spectrometry and gas chromatography-inductively coupled plasma mass spectrometry. To avoid possible analytical errors such as non-quantitative extraction and species degradation during sample preparation, different extraction methods were tested (microwave- and ultrasound-assisted extraction and mechanical stirring). The reference values were based on the unweighted means of results from the homogenisation and characterisation studies. The reference values obtained were 1,553 ± 87 and 534 ± 38 ng Sn g(-1) for DBT and TBT, respectively. In the uncertainty budget estimation, the sample inhomogeneity and between-method imprecision were taken into account. The concentrations of DBT and TBT in QCM are similar to those in the harbour sediment certified reference material PACS-2. Likewise, the levels of DBT and TBT are in the range of these compounds normally present in sewage sludge worldwide. In the future, the QCM will be used for an intercomparison study on DBT and TBT in sewage sludge, and as a day-to-day QCM during studies concerning the application of sewage sludge as an additive to artificial soil or as a raw material in civil engineering construction.

  17. Preliminary thermoluminescence and optically stimulated luminescence investigation of commercial pharmaceutical preparations towards the drug sterilization dosimetry.

    PubMed

    Kazakis, Nikolaos A; Tsirliganis, Nestor C; Kitis, George

    2014-09-01

    Drug sterilization with ionizing radiation is a well-established technology and is gaining ground the last decades due to its numerous advantages. Identification of irradiated drugs would be interesting and, in this respect, the present work aims, for the first time to the authors' best knowledge, to explore whether OSL and TL can be employed as methods for post-sterilization dosimetry on commercial drugs, i.e., as tools for the detection of irradiated drugs. Five widely used drugs, i.e., Daktarin(®), Aspirin(®), Panadol(®), Brufen(®) and Procef(®), are used for this purpose. Preliminary findings are very promising towards the post-sterilization dosimetry and the use of commercial drugs for normal and/or accidental dosimetry.

  18. Methods for routine control of irradiated food: Determination of the irradiation status of shellfish by thermoluminescence analysis

    NASA Astrophysics Data System (ADS)

    Schreiber, G. A.; Hoffmann, A.; Helle, N.; Bögl, K. W.

    1994-06-01

    In some countries, clearance has been given for treating certain types of shellfish by ionizing radiation in order to increase the shelf-life and to reduce health hazards which might be caused by contaminating microorganisms. In the present study, thermoluminescence (TL) analysis was used to examine the irradiation status of shellfish products purchased from local suppliers. For analysis minerals were isolated from the guts of the animals. Although on none of the examined products an irradiation treatment prior to analysis could be shown, the results obtained on non-irradiated and irradiated products have revealed that irradiation within the commercially used dose range can clearly be detected. Already first glow TL intensities of minerald indicated irradiation treatments. Normalized TL signals of non-irradiated and irradiated samples were clearly separated. By calculation of differences of TL intensities and TL signals between non-irradiated and irradiated samples in dependency of integration temperature an optimized integration area for glow curves was determined. The result of this study agree well with results obtained by two large-scale intercomparisons between food control laboratories to detect irradiation treatment of spices and herbal products as well as of fruit and vegetables by TL analysis of contaminating minerals.

  19. Thermoluminescence Response of Ge-Doped Cylindrical-, Flat- and Photonic Crystal Silica-Fibres to Electron and Photon Radiation.

    PubMed

    Entezam, A; Khandaker, M U; Amin, Y M; Ung, N M; Bradley, D A; Maah, J; Safari, M J; Moradi, F

    2016-01-01

    Study has been made of the thermoluminescence (TL) response of silica-based Ge-doped cylindrical, flat and photonic crystal fibres (referred to herein as PCF-collapsed) to electron (6, 12 and 20 MeV) and photon (6, 10 MV) irradiation and 1.25 MeV γ-rays, for doses from 0.1 Gy to 100 Gy. The electron and photon irradiations were delivered through use of a Varian Model 2100C linear accelerator located at the University of Malaya Medical Centre and γ-rays delivered from a 60Co irradiator located at the Secondary Standard Dosimetry Laboratory (SSDL), Malaysian Nuclear Agency. Tailor-made to be of various dimensions and dopant concentrations (6-10% Ge), the fibres were observed to provide TL yield linear with radiation dose, reproducibility being within 1-5%, with insensitivity to energy and angular variation. The sensitivity dependency of both detectors with respect to field size follows the dependency of the output factors. For flat fibres exposed to 6 MV X-rays, the 6% Ge-doped fibre provided the greatest TL yield while PCF-collapsed showed a response 2.4 times greater than that of the 6% Ge-doped flat fibres. The response of cylindrical fibres increased with core size. The fibres offer uniform response, high spatial resolution and sensitivity, providing the basis of promising TL systems for radiotherapy applications.

  20. Thermoluminescence Response of Ge-Doped Cylindrical-, Flat- and Photonic Crystal Silica-Fibres to Electron and Photon Radiation

    PubMed Central

    Entezam, A.; Khandaker, M. U.; Amin, Y. M.; Ung, N. M.; Bradley, D. A.; Maah, J.; Safari, M. J.; Moradi, F.

    2016-01-01

    Study has been made of the thermoluminescence (TL) response of silica-based Ge-doped cylindrical, flat and photonic crystal fibres (referred to herein as PCF-collapsed) to electron (6, 12 and 20 MeV) and photon (6, 10 MV) irradiation and 1.25 MeV γ-rays, for doses from 0.1 Gy to 100 Gy. The electron and photon irradiations were delivered through use of a Varian Model 2100C linear accelerator located at the University of Malaya Medical Centre and γ-rays delivered from a 60Co irradiator located at the Secondary Standard Dosimetry Laboratory (SSDL), Malaysian Nuclear Agency. Tailor-made to be of various dimensions and dopant concentrations (6–10% Ge), the fibres were observed to provide TL yield linear with radiation dose, reproducibility being within 1–5%, with insensitivity to energy and angular variation. The sensitivity dependency of both detectors with respect to field size follows the dependency of the output factors. For flat fibres exposed to 6 MV X-rays, the 6% Ge-doped fibre provided the greatest TL yield while PCF-collapsed showed a response 2.4 times greater than that of the 6% Ge-doped flat fibres. The response of cylindrical fibres increased with core size. The fibres offer uniform response, high spatial resolution and sensitivity, providing the basis of promising TL systems for radiotherapy applications. PMID:27149115

  1. A comparative study of terrestrial gamma dose rate in air measured by thermoluminescent dosimeter, portable survey meter and HPGe gamma spectrometer.

    PubMed

    Huang, Yan-Jun; Guo, Gui-Yin; He, Yi; Yang, Li-Tao; Shan, Zhen; Chen, Chao-Feng; Shang-Guan, Zhi-Hong

    2016-11-01

    In this paper, three different widely-used measurement techniques for environmental gamma dose rate were studied and compared, i.e., the thermoluminescent dosimeter, the portable survey meter and the spectrometric analysis. Thirteen investigation sites were selected, and the TLDs were arranged to accumulate the radiation signals during an interval of about one quarter, the instant dose rates by using a portable survey meter were collected around the site, and top surface soils were sampled in the surroundings for radionuclides analyzing in laboratory. The results from these methods were compared, which revealed high correlations. The differences and possible uncertainties for the three methods were analyzed, inspired a further study should be conducted to have more successful estimation of dose rate in surface air.

  2. Synthesis of β-Ca2P2O7:Tb(3+) to gamma radiation detection by thermoluminescence.

    PubMed

    Roman-Lopez, J; Lozano, I B; Cruz-Zaragoza, E; Castañeda, J I Guzman; Díaz-Góngora, J A I

    2017-03-06

    In this work, luminescent emissions of beta-calcium pyrophosphate doped with terbium ions (β-Ca2P2O7:Tb(3+)) were studied. The Ca2P2O7:Tb(3+) powders were prepared by precipitation and annealed at 900°C for 2h was applied on the powders to observe the beta phase. Radioluminescence measurements showed emission bands related with (5)D3 ((5)D4)→(7)FJ transitions of Tb(3+) ions. Three overlapped peaks at 126, 165 and 220°C were observed in thermoluminescence response. A linear TL dose-response in the range of 0.2-10Gy and an acceptable TL reproducibility were showed by the β-Ca2P2O7:Tb(3+) samples exposed to (60)Co gamma radiation. The TL glow curves were analyzed by Initial Rise method and Computational Glow-Curve Deconvolution assuming a General Order Kinetic model to evaluate the kinetic parameters related with the TL peaks.

  3. Change in thermoluminescence behaviour of cubic Gd2O3:Yb3+ phosphors with successive increase in Yb3+ ion concentrations

    NASA Astrophysics Data System (ADS)

    Tamrakar, Raunak Kumar; Bisen, D. P.; Upadhyay, Kanchan

    2017-01-01

    Nanocrystalline Yb3+ doped Gd2O3 phosphors were synthesized by solid state reaction method (SSRM), and effect of Yb3+ concentrations (1 mol% to 7 mol%) on thermoluminescence properties were studied. The XRD technique shows the cubic structure of prepared phosphor for different concentrations of Yb3+. No phase change was found due to the dopant concentration. The crystal size was calculated by Scherer's formula, which is found in 20-60 nm range. The same was also confirmed from the field emission gun scanning electron microscopy (FEGSEM) image, which shows the formation of nanospheres having diameter 20-60 nm range. They are found to be quite uniform in shapes and sizes. Functional group analysis was studied by Fourier transform infrared spectroscopy (FTIR) techniques and the elemental analysis of prepared phosphor was studied by energy dispersive X-ray spectroscopic (EDX) analysis. The samples were irradiated with UV and gamma radiation for the doses varying from 5 to 30 min for UV and 0.5 kGy to 2 kGy for gamma respectively and their thermoluminescence (TL) characteristics have been studied. The effect of heating rate (3-7 °C s-1) and effect of Yb3+ concentration in TL glow curve have been studied. The TL glow curve of nanophosphor shows a peak at around 130 °C for UV and at 247 °C for gamma irradiation respectively. The TL response of the sample irradiated with different gamma doses shows a linear behaviour from 0.5 kGy to 2 kGy and become sublinear behaviour in the range of 5-25 min UV exposure before it saturates with further increase in the dose. Simple glow curve structure, easy method of synthesis and the linear dose response make the nanocrystalline phosphor a good candidate for radiation dosimetry, especially for the estimation of high doses of gamma rays where the nanocrystalline phosphors generally saturated.

  4. The initial rise method extended to multiple trapping levels in thermoluminescent materials.

    PubMed

    Furetta, C; Guzmán, S; Ruiz, B; Cruz-Zaragoza, E

    2011-02-01

    The well known Initial Rise Method (IR) is commonly used to determine the activation energy when only one glow peak is presented and analysed in the phosphor materials. However, when the glow peak is more complex, a wide peak and some holders appear in the structure. The application of the Initial Rise Method is not valid because multiple trapping levels are considered and then the thermoluminescent analysis becomes difficult to perform. This paper shows the case of a complex glow curve structure as an example and shows that the calculation is also possible using the IR method. The aim of the paper is to extend the well known Initial Rise Method (IR) to the case of multiple trapping levels. The IR method is applied to minerals extracted from Nopal cactus and Oregano spices because the thermoluminescent glow curve's shape suggests a trap distribution instead of a single trapping level.

  5. Thermoluminescence properties of new ZnO nanophosphors exposed to beta irradiation

    NASA Astrophysics Data System (ADS)

    Cruz-Vázquez, C.; Bernal, R.; Burruel-Ibarra, S. E.; Grijalva-Monteverde, H.; Barboza-Flores, M.

    2005-04-01

    Novel ZnO nanophosphors were synthesized by thermal annealing of ZnS powders obtained by precipitation in a chemical bath deposition reaction. Pellet-shape samples were exposed to beta radiation in order to investigate their dosimetric capabilities under ionizing radiation. The dependence of thermoluminescence response in the 0.15-10.5 kGy dose range increased as the radiation dose increased. The composition and structure of the ZnO samples are dependent on the annealing time and temperature. Energy-dispersive X-ray spectrometry analyses and X-ray diffraction patterns, confirmed the change from amorphous ZnS to nanocrystalline ZnO (zincite) structure. The samples were beta irradiated and their thermoluminescence response as a function of dose exhibited good linear ranges, which make them very promising detectors and dosimeters suitable for ionizing radiation.

  6. Absorbed dose measurements on external surface of Kosmos-satellites with glass thermoluminescent detectors.

    PubMed

    Akatov YuA; Arkhangelsky, V V; Kovalev, E E; Spurny, F; Votochkova, I

    1989-01-01

    In this paper we present absorbed dose measurements with glass thermoluminescent detectors on external surface of satellites of Kosmos-serie flying in 1983-87. Experiments were performed with thermoluminescent aluminophosphate glasses of thicknesses 0.1, 0.3, 0.4, 0.5, and 1 mm. They were exposed in sets of total thickness between 5 and 20 mm, which were protected against sunlight with thin aluminized foils. In all missions, extremely high absorbed dose values were observed in the first layers of detectors, up to the thickness of 0.2 to 0.5 gcm-2. These experimental results confirm that, during flights at 250 to 400 km, doses on the surface of the satellites are very high, due to the low energy component of the proton and electron radiation.

  7. Thermoluminescence behavior of basaltic rocks collected in southeastern region of Turkey.

    PubMed

    Toktamış, Dilek; Toktamış, Hüseyin; Yazıcı, A Necmeddin

    2017-03-01

    Basalt is well known as an extrusive igneous rock erupts on land by volcanic eruption. It is darker, denser and finer grained compared to the familiar granite of the continents. The study reveals the thermoluminescence properties (TL) of basaltic rocks which collected in southeastern region of Turkey. With this study, the variations of glow curve of the basalt at the different grain sizes, different annealing temperature and different annealing time have been investigated. This study also includes, dose response and heating rate experiments. As a result, the basalt sample shows thermoluminescence properties with a wide peak about 200°C. The best TL sensitivity was observed at samples whose grain size is ~100µm. The basalt sample has a wide TL glow curve. A linearity for the values up to 155Gy and supralinearity between 155Gy and 615Gy in dose response are observed and it reaches to saturation beyond 615Gy. Thermal treatments at higher temperatures decrease the TL sensitivity.

  8. Preparation, characterization and thermally stimulated luminescence of ZnO nanophosphor

    NASA Astrophysics Data System (ADS)

    Manam, J.; Das, S.; Isaac, A.

    2009-10-01

    Pure nanocrystalline ZnO thermoluminescent phosphor was synthesized by chemical co-precipitation method. The prepared sample was characterized by XRD, SEM and FTIR. The powder samples when exposed to X-irradiation showed that the thermoluminescence response increases linearly with the increase of the time of X-irradiation. The glow curve exhibited two maxima centered at 116 and 207°C. The latter glow peak displays greater stability and sensitivity when the phosphor is exposed to X-irradiation at room temperature. The results indicate that this new ZnO phosphor is a promising detector and dosimeter for X-irradiation.

  9. Pooling of cultured samples and comparison of multistate laboratory workflows with the MagMAX sample preparation system and VetMAX quantitative polymerase chain reaction reagents for detection of Tritrichomonas foetus-colonized bulls.

    PubMed

    Effinger, Lee; Peddireddi, Lalitha; Simunich, Marilyn; Oberst, Richard; O'Connell, Catherine; Leyva-Baca, Ivan

    2014-01-01

    The objectives of the current study were 1) to compare sample preparation workflows and quantitative real-time polymerase chain reaction assays (qPCR) as currently used in veterinary diagnostic laboratories with a study protocol utilizing commercially available reagents for individual Tritrichomonas foetus testing, 2) to assess the accuracy of pooling cultured smegma samples followed by extraction and qPCR testing as used in the study laboratory, and 3) to assess the specificity of the currently used primers and probes by sequencing all positive and presumptive positive samples identified in the study laboratory in an attempt to capture any nucleotide variability between T. foetus isolates and to rule out false-positive results possibly due to Simplicimonas moskowitzi. Eight hundred three cultured smegma samples were collected from different regions of the United States with the collaboration of 5 veterinary testing laboratories. The samples were processed individually by the respective laboratories, and then sent to the study laboratory and retested using the study protocol. Comparison testing showed an overall agreement of 95.89% between the veterinary testing laboratories and the study laboratory. One hundred seventy-six positive or presumptive positive samples plus 625 negative qPCR samples were combined and retested using a pooling protocol. Pools consisted of 1 positive sample and 4 negative samples (1/5). These pools were processed using the same study laboratory protocols, and 96% of the positive samples were detected in these pools. Nested PCR followed by sequencing confirmed 175 of the 178 samples classified as positive or presumptive positive in the study laboratory as containing T. foetus-specific DNA.

  10. Detailed kinetic study of the thermoluminescence glow curve of synthetic quartz.

    PubMed

    Kitis, G; Pagonis, V; Carty, H; Tatsis, E

    2002-01-01

    A detailed kinetic analysis has been performed of the thermoluminescence (TL) glow curve of high purity synthetic quartz. The kinetic parameters of the glow peak at 110 degrees C were evaluated for doses ranging from 0.1 Gy to 100 Gy using glow curve deconvolution (GCD), initial rise, variable heating ratc and phosphorescence decay methods. All the methods gave results that agree within the experimental errors.

  11. Dosimetric study of thermoluminescent detectors in clinical photon beams using liquid water and PMMA phantoms.

    PubMed

    Matsushima, Luciana C; Veneziani, Glauco R; Sakuraba, Roberto K; da Cruz, José C; Campos, Letícia L

    2012-07-01

    The purpose of this study was the dosimetric evaluation of thermoluminescent detectors of calcium sulphate doped with dysprosium (CaSO4:Dy) produced by IPEN compared to the TL response of lithium fluoride doped with magnesium and titanium (LiF:Mg,Ti) dosimeters and microdosimeters produced by Harshaw Chemical Company to clinical photon beams dosimetry (6 and 15 MV) using liquid water and PMMA phantoms.

  12. Low-temperature thermoluminescence spectra of rare-earth-doped lanthanum fluoride

    NASA Astrophysics Data System (ADS)

    Yang, B.; Townsend, P. D.; Rowlands, A. P.

    1998-01-01

    Lanthanum fluoride consistently shows two strong thermoluminescence glow peaks at low temperature in pure material near 90 and 128 K. A model is proposed in which these thermoluminescence peaks arise from the annealing of halogen defect sites, similar to the H and Vk centers of the alkali halides. Relaxation and decay of these defects in the pure LaF3 lattice results in broad-band intrinsic luminescence. Addition of rare-earth-impurity ions has two effects. First, the broad-band emission is replaced by narrow-band line emission defined by the trivalent rare-earth dopants. Second, it preferentially determines the formation of the halogen defect sites at impurity lattice sites and such sites appear to increase in thermal stability since the glow peak temperature increases from 128 K in the intrinsic material up to 141 K through the sequence of rare-earth dopants from La to Er. The temperature movement directly correlates with the changes in ionic size of the rare-earth ions, when allowance is made for differences in effective coordination number of the impurity ions. The data suggest two alternative lattice sites can be occupied. The model emphasizes that the intense thermoluminescence signals arise from internal charge rearrangements and annealing of defect complexes, rather than through the more conventional model of separated charge traps and recombination centers. At higher temperatures there is a complex array of glow peaks which depend not only on the dopant concentration but also are specific to each rare earth. Such effects imply defect models giving thermoluminescence within localized complexes and possible reasons are mentioned.

  13. Study of thermoluminescence response of purple to violet amethyst quartz from Balikesir, Turkey

    NASA Astrophysics Data System (ADS)

    Nur, N.; Yeğingil, Z.; Topaksu, M.; Kurt, K.; Doğan, T.; Sarıgül, N.; Yüksel, M.; Altunal, V.; Özdemir, A.; Güçkan, V.; Günay, I.

    2015-09-01

    In thermoluminescence (TL) dosimetry, the phosphor amethyst quartz as a thermoluminescent, appears to be one of the materials arousing the highest interest. In this study the dosimetric characteristics of natural amethyst quartz crystals collected from Balikesir-Dursunbey (Turkey) were investigated for the purpose of determination of the general properties that phosphors should have in order to be useful for thermoluminescence dosimetry. The natural thermoluminescence was drained by annealing the powder samples at 450 °C for 1.5 h. The effects of high temperature annealing, dose response curves, glow curves after a postirradiation annealing, reusability of the samples and storage of trapped electrons in dark at room temperature were clarified through irradiating the samples with the desired exposures by 90Sr/90Y beta particles. Isothermal annealing before and after irradiation was found to have a definite effect upon the TL glow curve of amethyst crystal powder. The same sample varied in sensitivity depending upon its previous thermal and radiation history. The peak heights of the glow peaks were examined with respect to dose response at dose levels between 1 Gy and 5 kGy. The intermediate temperature (IT) and high temperature (HT) peaks of 230 °C and 300 °C, respectively, exhibit dose-response curves as superlinear when dose is on the logarithmic scale except the dose response of 300 °C peak for the dose values of 1 < D < 20 Gy in which linear dose response was acquired. At the end of the storage time between exposure and readout which was about one month at room temperature, the emitted light reduction was 14% comparing to the initial state. Repeating the measurements of the same sample, exposed with 0.1, 0.5, 0.8 and 1 kGy beta exposures, resulted in between 4% and 11% increase in the TL sensitivity of the material.

  14. Low-temperature thermoluminescence spectra of rare-earth-doped lanthanum fluoride

    SciTech Connect

    Yang, B.; Townsend, P.D.; Rowlands, A.P.

    1998-01-01

    Lanthanum fluoride consistently shows two strong thermoluminescence glow peaks at low temperature in pure material near 90 and 128 K. A model is proposed in which these thermoluminescence peaks arise from the annealing of halogen defect sites, similar to the H and V{sub k} centers of the alkali halides. Relaxation and decay of these defects in the pure LaF{sub 3} lattice results in broad-band intrinsic luminescence. Addition of rare-earth-impurity ions has two effects. First, the broad-band emission is replaced by narrow-band line emission defined by the trivalent rare-earth dopants. Second, it preferentially determines the formation of the halogen defect sites at impurity lattice sites and such sites appear to increase in thermal stability since the glow peak temperature increases from 128 K in the intrinsic material up to 141 K through the sequence of rare-earth dopants from La to Er. The temperature movement directly correlates with the changes in ionic size of the rare-earth ions, when allowance is made for differences in effective coordination number of the impurity ions. The data suggest two alternative lattice sites can be occupied. The model emphasizes that the intense thermoluminescence signals arise from internal charge rearrangements and annealing of defect complexes, rather than through the more conventional model of separated charge traps and recombination centers. At higher temperatures there is a complex array of glow peaks which depend not only on the dopant concentration but also are specific to each rare earth. Such effects imply defect models giving thermoluminescence within localized complexes and possible reasons are mentioned. {copyright} {ital 1998} {ital The American Physical Society}

  15. Dating the Morasko meteorite fall by natural thermoluminescence of the fusion crust

    NASA Astrophysics Data System (ADS)

    Fedorowicz, Stanisław; Stankowski, Wojciech T. J.

    2016-09-01

    The date of fall of the Morasko iron meteorite was determined by means of thermoluminescence measurements of the fusion crust and related local materials. Three small pieces, commonly referred to as `shrapnel', were used. The results obtained are 4.5-5.0 ka, which is in good agreement with previous estimates of 4-6 ka on the basis of radiometric, do-simetric and palynological methods.

  16. Changes in photosynthetic metabolism induced by tobamovirus infection in Nicotiana benthamiana studied in vivo by thermoluminescence.

    PubMed

    Sajnani, Carlota; Zurita, Jorge L; Roncel, Mercedes; Ortega, José M; Barón, Matilde; Ducruet, Jean-Marc

    2007-01-01

    * In thylakoids from Nicotiana benthamiana infected with the pepper mild mottle virus (PMMoV), a decreased amount of the PsbP and PsbQ proteins of photosystem II and different proteins of the Calvin cycle have been previously observed. We used thermoluminescence to study the consequences in vivo. * Measurements on unfrozen discs from symptomatic and asymptomatic leaves of plants infected by two tobamovirus PMMoV-S and PMMoV-I strains were compared with homologous samples in control plants. * Thermoluminescence emission did not reveal noticeable alteration of PSII electron transfer activity in infected symptomatic leaves. In these leaves, the relative intensity of the 'afterglow' emission indicated an increase of the NADPH + ATP assimilatory potential, contrasting with its decrease in asymptomatic leaves. High-temperature thermoluminescence, as a result of peroxides, increased in symptomatic and asymptomatic leaves. * In young infected leaves, PSII activity is preserved, producing a high assimilatory potential. Older asymptomatic leaves export more nutrients towards young infected leaves. This depresses their assimilatory potential and weakens their defence mechanisms against reactive oxygen species, resulting in higher peroxide content.

  17. Thermoluminescence as a complementary technique for the toxicological evaluation of chemicals in photosynthetic organisms.

    PubMed

    Repetto, Guillermo; Zurita, Jorge L; Roncel, Mercedes; Ortega, José M

    2015-01-01

    Thermoluminescence is a simple technique very useful for studying electron transfer reactions on photosystem II (standard thermoluminescence) or the level of lipid peroxidation in membranes (high temperature thermoluminescence) in photosynthetic organisms. Both techniques were used to investigate the effects produced on Chlorella vulgaris cells by six compounds: the chemical intermediates bromobenzene and diethanolamine, the antioxidant propyl gallate, the semiconductor indium nitrate, the pesticide sodium monofluoroacetate and the antimalarial drug chloroquine. Electron transfer activity of the photosystem II significantly decreased after the exposure of Chlorella cells to all the six chemicals used. Lipid peroxidation was slightly decreased by the antioxidant propyl gallate, not changed by indium nitrate and very potently stimulated by diethanolamine, chloroquine, sodium monofluoroacetate and bromobenzene. For five of the chemicals studied (not bromobenzene) there is a very good correlation between the cytotoxic effects in Chlorella cells measured by the algal growth inhibition test, and the inhibition of photosystem II activity. The results suggest that one very important effect of these chemicals in Chlorella cells is the inhibition of photosynthetic metabolism by the blocking of photosystem II functionality. In the case of sodium monofluoroacetate, diethanolamine and chloroquine this inhibition seems to be related with the induction of high level of lipid peroxidation in cells that may alter the stability of photosystem II. The results obtained by both techniques supply information that can be used as a supplement to the growth inhibition test and allows a more complete assessment of the effects of a chemical in photosynthetic organisms of aquatic ecosystems.

  18. Laboratory investigations

    NASA Technical Reports Server (NTRS)

    Russell, Ray W.

    1988-01-01

    Laboratory studies related to cometary grains and the nuclei of comets can be broken down into three areas which relate to understanding the spectral properties, the formation mechanisms, and the evolution of grains and nuclei: (1) Spectral studies to be used in the interpretation of cometary spectra; (2) Sample preparation experiments which may shed light on the physical nature and history of cometary grains and nuclei by exploring the effects on grain emissivities resulting from the ways in which the samples are created; and (3) Grain processing experiments which should provide insight on the interaction of cometary grains with the environment in the immediate vicinity of the cometary nucleus as the comet travels from the Oort cloud through perihelion, and perhaps even suggestions regarding the relationship between interstellar grains and cometary matter. A summary is presented with a different view of lab experiments than is found in the literature, concentrating on measurement techniques and sample preparations especially relevant to cometary dust.

  19. Influence of halide flux on the crystallinity, microstructure and thermoluminescence properties of CdSiO{sub 3}:Co{sup 2+} nanophosphor

    SciTech Connect

    Manjunatha, C.; Nagabhushana, B.M.; Sunitha, D.V.; Nagabhushana, H.; Sharma, S.C.; Chakradhar, R.P.S.

    2013-01-15

    Graphical abstract: TL glow curves of CdSiO{sub 3}:Co{sup 2+} different alkali flux (inset without adding flux). Display Omitted Highlights: ► CdSiO{sub 3}:Co{sup 2+} (1–7 mol%) nanocrystalline phosphors synthesized by combustion route. ► Flux effect on thermoluminescence behavior of CdSiO{sub 3}:Co{sup 2+} reported for first time. ► Addition of 2 wt% of flux would drastically enhance the TL properties. ► Well resolved single glow peak at ∼170 °C was recorded for all the samples. ► Among all the alkali flux, NaCl shows highest TL peak intensity. -- Abstract: CdSiO{sub 3}:Co{sup 2+} (1–7 mol %) nanophosphors have been prepared via solution combustion method with post calcination at 800 °C for 2 h for the first time. The formation of expected monoclinic phase was investigated by Powder X-ray diffraction (PXRD) measurements. The effect of different fluxes like NaF, NaCl, NH{sub 4}F and NH{sub 4}Cl on the crystallinity, phase and morphology of CdSiO{sub 3} was investigated in detail. The crystallinity of the samples can be greatly enhanced by using fluxes rather than increasing the calcination temperature. Scanning electronic micrograph (SEM) image shows that the powder morphologies are highly influenced by flux addition. The addition of 2 wt% of fluxes would drastically enhance the crystallinity when NaCl, NH{sub 4}F and NH{sub 4}Cl fluxes are used. A well resolved single thermoluminescent glow peak at ∼170 °C was recorded for all the samples. Among all the halide fluxes, NaCl flux was found to be the potential one in enhancing the TL peak intensity along with crystallinity.

  20. Addressing the Professional Preparation of Future Science Teachers To Teach Hands-On Science: A Pilot Study of a Laboratory Model.

    ERIC Educational Resources Information Center

    Sweeney, Aldrin E.; Paradis, Jeffrey A.

    2003-01-01

    Reports on a study of a pilot model of a laboratory training course that provides preservice secondary science teachers the opportunity to explore pedagogical possibilities and gain hands-on experience running a general chemistry lab. (DDR)

  1. Evaluation of tooth preparations for Class II cavities using magnification loupes among dental interns and final year BDS students in preclinical laboratory

    PubMed Central

    Narula, Khyati; Kundabala, Mala; Shetty, Neetha; Shenoy, Ramya

    2015-01-01

    Background: With the advances in optical technology, dentistry has been benefitted in varied ways over the ages. Aim: The aim of this study was to assess the effect of dental magnification loupes on psychomotor skill acquisition during preclinical operative exercise. Methods: 40 Typhodont teeth tooth no. 36 and 46 (Frasaco - U.S.A.) were mounted on the acrylic lower jaw base of Phantom Head. Teeth are prepared for class II (MO) cavity with conservative design using micromotor, mouth mirror and probe. Tooth no.36 was prepared using magnifying loupes while tooth no.46 was prepared without the loupes. Data collected was statistically analyzed using Chi square test. Results: The results revealed that tooth preparations were better under magnifying loupes as compared to those without it with statistically significant difference with Kappa value 0.64 for samples with loupes and 0.76 for without loupes. Moreover, the study samples expressed their difficulty for using the magnifying loupes during the tooth preparation since they were using it for the first time. Conclusions: Magnifying loupes help the dental students to have better vision, thus improved dexterity with hands while preparing the tooth for restoration. However, dental students have to get adapted to the loupes for the ease of using loupes. Using loupes frequently may help them to get adapted to the loupes. PMID:26180411

  2. Pitfalls, artefacts and open questions in chlorophyll thermoluminescence of leaves or algal cells.

    PubMed

    Ducruet, Jean-Marc

    2013-07-01

    Thermoluminescence of intact photosynthetic organisms, leaves or algal cells, raises specific problems. The constitutive S2/3Q B (-) B bands constitute major probes of the state of photosystem II in vivo. The presence of a dark-stable acidic lumen causes a temperature downshift of B bands, specially the S3 B band, providing a lumen pH indicator. This is accompanied by a broadening of the S3 B band that becomes an envelope of elementary B bands. The occasional AT, Q and C bands are briefly examined in an in vivo context. It is emphasized that freezing below the nucleation temperature is not necessary for physiological studies, but a source of artefacts, hence should be avoided. In intact photosynthetic structures, a dark-electron transfer from stroma reductants to the quinonic acceptors of photosystem II via the cyclic/chlororespiratory pathways, strongly stimulated by moderate warming, gives rise to the afterglow (AG) luminescence emission that reflects chloroplast energy status. The decomposition of complex TL signals into elementary bands is necessary to determine the maximum temperature T m and the area of each of them. A comparison of TL signals after 1 flash and 2 flashes prevents from confusing the three main bands observed in vivo, i.e. the S2 and S3 B bands and the AG band. Finally, the thermoluminescence bands arising sometimes above 50 °C are mentioned. The basic principles of (thermo)luminescence established on isolated thylakoids should not be applied directly without a careful examination of in vivo conditions.

  3. Thermoluminescence of Eu activated LiF nanophosphors

    SciTech Connect

    Kumar, Satinder; Sharma, A. K.; Lochab, S. P.; Kumar, Ravi

    2012-06-05

    Nanocrystalline lithium fluoride (LiF) phosphors prepared by the chemical co-precipitation method at 8.00 pH value have been activated with Eu (0.01, 0.03, 0.07 and 0.1%nt;) as single dopants. The formation of nanocrystalline structure has been confirmed by X-ray diffraction. Thermolumniscence (TL) properties of LiF: Eu nano-phosphors irradiated with gamma rays at different doses of 100 Gy - 10 kGy have been further studied. There is only one main glow peak at around 122 deg. C; which shifts to higher temperature with an increase in doping concentration at all studied irradiation doses. However, the glow peak shifts to lower temperature with an increase in irradiation dose from 100 Gy to 10 kGy. The LiF nano-crystallites synthesized at 8.00 pH and activated with 0.03%nt; Eu are found to have maximum TL sensitivity at studied gamma doses.

  4. Dosimetric Characteristics of a LKB:Cu,Mg Solid Thermoluminescence Detector

    NASA Astrophysics Data System (ADS)

    Yasser Saleh Mustafa, Alajerami; Suhairul, Hashim; Ahmad Termizi, Ramli; Muneer Aziz, Saleh; Ahmad Bazlie, Bin Abdul Kadir; Mohd., Iqbal Saripan

    2013-01-01

    We present the main thermoluminescence characteristics of a newly borate glass dosimeter modified with lithium and potassium carbonate (LKB) and co-doped with CuO and MgO. An enhancement of about three times has been shown with the increment of 0.1mol% MgO as a co-dopant impurity. The effects of dose linearity, storage capacity, effective atomic number and energy dose response are studied. The proposed dosimeter shows a simple glow curve, good linearity up to 103 Gy, close effective atomic number and photon energy independence. The current results suggest using the proposed dosimeter in different dosimetric applications.

  5. The read-out system of spatial distribution of thermoluminescence in meteorites

    NASA Technical Reports Server (NTRS)

    Ninagawa, K.; Yamamoto, I.; Takano, Y.; Wada, T.; Yamashita, Y.; Takaoka, N.

    1985-01-01

    The thermoluminescence (TL) technique used for dating the terrestrial age of meteorites is based on the TL fading of interior samples. The depth dependence of the TL for Antarctic meteorites with fusion crust is measured. Usually, meteorites are powdered and their TL measured under a photomultiplier. In this case, a TL spatial distribution of a cross section of antarctic meteorites is measured using a read out system of spatial distribution of TL, since a meteorite is made up of inhomogeneous material. Antarctic meteorites MET-78028(L6) and ALH-77278(L13) are used.

  6. Thermoluminescence response of dysprosium doped strontium tetraborate glasses subjected to electron irradiations.

    PubMed

    Lim, Tou Ying; Wagiran, H; Hussin, R; Hashim, S

    2015-08-01

    The paper presents the thermoluminescence (TL) response of strontium tetraborate glass subjected to electron irradiations at various Dy2O3 concentrations ranging from 0.00 to 1.00mol%. All glass samples exhibited single broad peak with maximum peak temperature positioned at 170-215°C. The optimum TL response was found at Dy2O3 concentration 0.75mol%. This glass showed good linearity and higher sensitivity for 7MeV compared to 6MeV electrons. Analysis of kinetic parameters showed that the glasses demonstrate second order kinetic.

  7. Thermoluminescence response and glow curve structure of Sc₂TiO₅ ß-irradiated.

    PubMed

    Muñoz, I C; Brown, F; Durán-Muñoz, H; Cruz-Zaragoza, E; Durán-Torres, B; Alvarez-Montaño, V E

    2014-08-01

    Discandium titanate (Sc2TiO5) powder was synthesized in order to analyze its thermoluminescence (TL) response. The TL glow curve structure shows two peaks: at 453-433 K and at 590-553 K. The TL beta dose-response has a linear behavior over the dose range 50-500 Gy. The T(stop) preheat method shows five glow peaks that were taken into account to calculate the kinetic parameters using the CGCD procedure. TL results support the possible use of Sc2TiO5 as a new phosphor in high ß-dose dosimetry.

  8. Charge trapping induced by plasma in alumina electrode surface investigated by thermoluminescence and optically stimulated luminescence

    SciTech Connect

    Ambrico, P. F.; Ambrico, M.; Schiavulli, L.; Ligonzo, T.; Augelli, V.

    2009-02-02

    The plasma of a dielectric barrier discharge can fill traps in the alumina that cover the electrode. Trap energies and lifetimes are estimated by thermoluminescence and optically stimulated luminescence. Comparison with similar results for traps created by other radiation sources clarifies the mechanisms regulating this effect. Alumina's trap energies are approximately 1 eV, and the traps remain active for several days after plasma exposure. These results could be important to keep dielectric barrier discharge plasmas uniform since a trapped charge can be an electron reservoir.

  9. Exploring stable thermoluminescence signal in natural Barite (BaSO4) for retrospective dosimetry.

    PubMed

    Sharma, Suchinder K; Thomas, Jugina; Pandian, M S; Rao, P S; Gartia, R K; Singhvi, Ashok K

    2015-11-01

    We explore the possible use of Barite (BaSO4) for radiation dosimetry and geochronology using thermoluminescence technique. Natural Barite with Mn as an impurity has a glow peak at 608K with a minimum detectable dose of 1.45±0.12mGy. This peak shows ~35% fading on 30 days of storage time and is photo-bleachable with excellent reproducibility on repeated read-out. The sensitivity changes with dose and evidence of athermal fading is also seen. We infer that the signal can be used for both retrospective dosimetry and geochronology of young deposits extending to 20ka.

  10. Intrinsic Dosimetry: Elemental Composition Effects on the Thermoluminescence of Commercial Borosilicate Glass

    SciTech Connect

    Richard A. Clark; J. David Robertson; Jon M. Schwantes

    2013-12-01

    Intrinsic dosimetry is the method of measuring total absorbed dose received by the walls of a container holding radioactive material. By considering this dose in tandem with the physical characteristics of the radioactive material housed within the container, this method can provide enhanced pathway information for interdicted radioactive samples. Thermoluminescence (TL) dosimetry was used to measure ionizing radiation dose effects on stock borosilicate glass. Differences in TL glow curve shape and intensity were observed for glasses from different geographical origins. The different TL signatures strongly correlated with the concentration of alkaline earth metals and the ratio of sodium to the total amount of alkali metal present in the borosilicate glass.

  11. Intrinsic Dosimetry. Elemental Composition Effects on the Thermoluminescence of Commercial Borosilicate Glass

    SciTech Connect

    Clark, Richard A.; Robertson, J. David; Schwantes, Jon M.

    2013-07-05

    Intrinsic dosimetry is the method of measuring total absorbed dose received by the walls of a container holding radioactive material. By considering this dose in tandem with the physical characteristics of the radioactive material housed within the container, this method can provide enhanced pathway information for interdicted radioactive samples. Thermoluminescence (TL) dosimetry was used to measure ionizing radiation dose effects on stock borosilicate glass. Differences in TL glow curve shape and intensity were observed for glasses from different geographical origins. The different TL signatures strongly correlated with the concentration of alkaline earth metals and the ratio of sodium to the total amount of alkali metal present in the borosilicate glass.

  12. The natural thermoluminescence of meteorites. II - Meteorite orbits and orbital evolution

    NASA Technical Reports Server (NTRS)

    Benoit, P. H.; Sears, D. W. G.; Mckeever, S. W. S.

    1991-01-01

    The present consideration of natural thermoluminescence (TL) data for 26 meteorites leads to calculation results for equilibrium natural TL level in ordinary chondrites that are indicative of TL's usefulness as an indicator of perihelion. Comparisons of data with cosmic ray exposure ages shows natural TL levels to be partly related to exposure age; meteorites with high exposure ages have generally lower ranges of natural TL than those with low ages, perhaps reflecting orbital evolution in light of the evolution of mature meteorite orbits to lower perihelia. It is confirmed that only a small proportion of meteorites have had low-perihelia orbits over the most recent 100,000 years.

  13. A thermoluminescence study of experimentally shock-loaded oligoclase and bytownite

    NASA Technical Reports Server (NTRS)

    Hartmetz, Christopher P.; Sears, Derek W. G.; Ostertag, Rolf

    1986-01-01

    The thermoluminescence (TL) properties of a terrestrial oligoclase and a bytownite shock-loaded to pressures of 10.5-45 GPa are measured. Glow curves and TL sensitivity levels for the oligoclase and bytownite samples are presented and analyzed; it is detected that shock causes a decrease in the TL sensitivity and changes the shape of the glow curve. The causes of the decrease in TL sensitivity and peak temperature and width variations are examined. Shock-induced disordering of the Al, Si chain, and ordinary chondrite shocks are studied.

  14. Thermoluminescence study of polyminerals extracted from clove and marjoram for detection purposes.

    PubMed

    Marcazzó, J; Cruz-Zaragoza, E; Mendoza, J E; Ramos Reyes, E; Brown, F

    2012-12-01

    Food irradiation is a widely employed technology for food treatment. Since in several countries no regulations prevail, it is difficult to detect whether food has been irradiated or not. Among different analytical methods the study of the thermoluminescent (TL) emission of polymineral extracted from food is one of the most useful physical identification method. The aim of this work is to analyze the TL properties of inorganic polyminerals extracted from commercial clove (Syzygium aromaticum L.) and marjoram (Origanum majorana L.) spices exposed to (60)Co gamma radiation for detection purposes. The feasibility of using the TL method for irradiated food detection and absorbed dose determination is assessed.

  15. Thermoluminescence of novel MgO-CeO2 obtained by a glycine-based solution combustion method.

    PubMed

    Barrón, Victor Ramón Orante; Ochoa, Flor María Escobar; Vázquez, Catalina Cruz; Bernal, Rodolfo

    2016-11-01

    Thermoluminescence dosimetry properties of novel MgO-CeO2 obtained by solution combustion synthesis in a glycine-nitrate process, are presented for the very first time. X-ray diffraction indicates the presence of cubic MgO and cerianite (CeO2) for the annealed powder samples. Dosimetry features such as linear behaviour of the dose response without saturation in the dose interval studied, as well as asymptotic behaviour of the thermoluminescent signal fading place MgO-CeO2 phosphor as a promising material for low-dose radiation dosimetry applications.

  16. Evaluation and Adaptation of a Laboratory-Based cDNA Library Preparation Protocol for Retrospective Sequencing of Archived MicroRNAs from up to 35-Year-Old Clinical FFPE Specimens

    PubMed Central

    Loudig, Olivier; Wang, Tao; Ye, Kenny; Lin, Juan; Wang, Yihong; Ramnauth, Andrew; Liu, Christina; Stark, Azadeh; Chitale, Dhananjay; Greenlee, Robert; Multerer, Deborah; Honda, Stacey; Daida, Yihe; Spencer Feigelson, Heather; Glass, Andrew; Couch, Fergus J.; Rohan, Thomas; Ben-Dov, Iddo Z.

    2017-01-01

    Formalin-fixed paraffin-embedded (FFPE) specimens, when used in conjunction with patient clinical data history, represent an invaluable resource for molecular studies of cancer. Even though nucleic acids extracted from archived FFPE tissues are degraded, their molecular analysis has become possible. In this study, we optimized a laboratory-based next-generation sequencing barcoded cDNA library preparation protocol for analysis of small RNAs recovered from archived FFPE tissues. Using matched fresh and FFPE specimens, we evaluated the robustness and reproducibility of our optimized approach, as well as its applicability to archived clinical specimens stored for up to 35 years. We then evaluated this cDNA library preparation protocol by performing a miRNA expression analysis of archived breast ductal carcinoma in situ (DCIS) specimens, selected for their relation to the risk of subsequent breast cancer development and obtained from six different institutions. Our analyses identified six miRNAs (miR-29a, miR-221, miR-375, miR-184, miR-363, miR-455-5p) differentially expressed between DCIS lesions from women who subsequently developed an invasive breast cancer (cases) and women who did not develop invasive breast cancer within the same time interval (control). Our thorough evaluation and application of this laboratory-based miRNA sequencing analysis indicates that the preparation of small RNA cDNA libraries can reliably be performed on older, archived, clinically-classified specimens. PMID:28335433

  17. Free the data: one laboratory's approach to knowledge-based genomic variant classification and preparation for EMR integration of genomic data.

    PubMed

    Bean, Lora J H; Tinker, Stuart W; da Silva, Cristina; Hegde, Madhuri R

    2013-09-01

    Current technology allows clinical laboratories to rapidly translate research discoveries from small patient cohorts into clinical genetic tests; therefore, a potentially large proportion of sequence variants identified in individuals with clinical features of a genetic disorder remain unpublished. Without a mechanism for clinical laboratories to share data, interpretation of sequence variants may be inconsistent. We describe here the two components of Emory Genetics Laboratory's (EGL) in-house developed data management system. The first is a highly curated variant database with a data structure designed to facilitate sharing of information about variants identified at EGL with curated databases. This system also tracks changes in variant classifications, creating a record of previous cases in need of updated reports when a classification is changed. The second component, EmVClass, is a Web-based interface that allows any user to view the inventory of variants classified at EGL. These software tools provide a solution to two pressing issues faced by clinical genetics laboratories: how to manage a large variant inventory with evolving variant classifications that need to be communicated to healthcare providers and how to make that inventory of variants freely available to the community.

  18. Preparation of a Cobalt(II) Cage: An Undergraduate Laboratory Experiment That Produces a ParaSHIFT Agent for Magnetic Resonance Spectroscopy

    ERIC Educational Resources Information Center

    Burns, Patrick J.; Tsitovich, Pavel B.; Morrow, Janet R.

    2016-01-01

    Laboratory experiments that demonstrate the effect of paramagnetic complexes on chemical shifts and relaxation times of protons are a useful way to introduce magnetic resonance spectroscopy (MRS) probes or magnetic resonance imaging (MRI) contrast agents. In this undergraduate inorganic chemistry experiment, a paramagnetic Co(II) cage complex is…

  19. Synthesis, characterizations and investigation of thermoluminescence properties of strontium pyrophosphate doped with metals

    NASA Astrophysics Data System (ADS)

    Ilkay, L. S.; Ozbayoglu, G.; Yilmaz, A.

    2014-11-01

    Strontium pyrophosphate, Sr2P2O7, was synthesized by solid-state synthesis method; the product was co-doped with copper-silver (Cu-Ag), copper-indium (Cu-In) and manganese-praseodymium (Mn-Pr) oxides (CuO, MnO, In2O3, Pr6O11 and AgNO3) by solid-state reaction method. The variation of dopant concentrations was investigated from 0.5 to 15% by weight. In addition to these processes, chemical characterizations of samples and the investigation of thermoluminescence (TLD) properties of strontium pyrophosphate with and without dopants were conducted. For the characterization; powder X-ray Diffraction (XRD) were implemented for phase purity of samples. Fourier Transform Infrared Spectroscopy (FTIR) was used to determine whether the bond structures were affected from the doping or not. Thermoluminescence (TLD) analyses were conducted on strontium pyrophosphate doped with different amounts of dopants for the first time. Glow curves showed that intensities were affected by different amounts of dopants. It can be concluded from that strontium pyrophosphate doped with 7% MnO and 1% Pr6O11 had the most powerful peak intensity around 160 °C and dosimetric property for promising application.

  20. Thermoluminescence of contaminating minerals for the detection of radiation treatment of dried fruits

    NASA Astrophysics Data System (ADS)

    Khan, H. M.; Bhatti, Ijaz A.; Delincée, Henry

    2002-03-01

    Several types of dry fruits (pistachio nut, dried apricot, almond and raisins) have been investigated for detection of their radiation treatment by gamma rays or electron beam using thermoluminescence (TL) measurements. These samples were irradiated to 1.0-3.0 kGy (gamma rays) or 0.75-3.9 kGy (10 MeV electron beam). Thermoluminescence glow curves for the contaminating minerals separated from the dry fruits were recorded between the temperature range of 50°C and 500°C. In all the cases, the intensity of TL signal for the irradiated dry fruits was 1-3 orders of magnitudes higher than the TL intensity of the corresponding unirradiated control samples allowing clear distinction between the irradiated and unirradiated samples. These results were normalized by re-irradiating the mineral grains with a gamma-ray dose of 1.0 kGy, and a second glow curve was recorded. The ratio of intensity of the first glow curve (TL 1) to that after the normalization dose (TL 2), i.e. (TL 1/TL 2) was determined and compared with the recommended threshold values. These parameters, together with comparison of the shape of the first glow curve, gave unequivocal results about the radiation treatment of the dry fruit samples.

  1. Annealing studies of the thermoluminescence of meteorites and implications for their metamorphic history

    SciTech Connect

    Guimon, R.K.

    1986-01-01

    The application of thermoluminescence to study metamorphism in the type 3 ordinary chondrites and five CAI from the Allende meteorite is explored. It has been found that the changes in the shape of the TL curve provide insight into the thermal history of the meteorites and meteoritic components. It is also shown that for ordinary chondrites, the TL sensitivity depends on the amount of feldspar present which, in turn, is governed by the intensity of metamorphism experienced. A type 3.4 ordinary chondrite shows changes in the peak temperature and width occurred upon annealing. These parameters showed a discontinuous increase after annealing at 800/sup 0/C; the peak temperature jumped from 130 to 200/sup 0/C and peak width increased from 90 to 150/sup 0/C. These changes in the TL emission characteristics suggest that type 3.3-3.5 ordinary chondrites have a low-feldspar as the dominant TL phosphor and > 3.5 have high feldspar as the phosphor. Thermoluminescence therefore provides a means of paleothermometry. In addition, experiments were performed aimed at causing the crystallization of feldspar in mesostasis glass in an attempt to reproduce the trends of increasing TL sensitivity with metamorphism. At high temperatures and longer annealing times, increases in TL sensitivity by factors of up to 40 were observed.

  2. Thermoluminescence property of LiMgF3 erbium activated phosphor.

    PubMed

    Muñoz, I C; Cruz-Zaragoza, E; Favalli, A; Furetta, C

    2012-05-01

    The perovskite-like LiMgF(3):ErF(3) pellets were obtained from the melt formed by LiF and MgF(2) mixed salts in the stoichiometric ratio. The perovskite material was doped with 1, 2 and 4 mol% of ErF(3) impurity. The pellets samples were (60)Co gamma irradiated and their thermoluminescence (TL) properties were analyzed, i.e., dose-response, fading at RT and under UV irradiation, TL signal reproducibility, and kinetic parameters. The intensity of the TL response against irradiation dose was increased remarkably by the high concentration of impurity, and a linear dose-response was observed in the range of 1-10 Gy. The fading observed at RT was about 10-30% after 24h from irradiation. All samples were exposed from 1 to 200 Gy gamma dose range. The TL glow peaks were found around 367-376, 438-447, 509-521, and 594-611 K, when the doped samples were 1, 2 and 4 mol% of the erbium impurity concentration. The thermoluminescence kinetics parameters of the glow curves have been analyzed using the Computerized Glow Curve Deconvolution (CGCD) method.

  3. Sensitive Fibre-Based Thermoluminescence Detectors for High Resolution In-Vivo Dosimetry.

    PubMed

    Ghomeishi, Mostafa; Mahdiraji, G Amouzad; Adikan, F R Mahamd; Ung, N M; Bradley, D A

    2015-08-28

    With interest in the potential of optical fibres as the basis of next-generation thermoluminescence dosimeters (TLDs), the development of suitable forms of material and their fabrication has become a fast-growing endeavour. Present study focuses on three types of Ge-doped optical fibres with different structural arrangements and/or shapes, namely conventional cylindrical fibre, capillary fibre, and flat fibre, all fabricated using the same optical fibre preform. For doses from 0.5 to 8 Gy, obtained at electron and photon energies, standard thermoluminescence (TL) characteristics of the optical fibres have been the subject of detailed investigation. The results show that in collapsing the capillary fibre into a flat shape, the TL yield is increased by a factor of 5.5, the yield being also some 3.2 times greater than that of the conventional cylindrical fibre fabricated from the same perform. This suggests a means of production of suitably sensitive TLD for in-vivo dosimeter applications. Addressing the associated defects generating luminescence from each of the optical fibres, the study encompasses analysis of the TL glow curves, with computerized glow curve deconvolution (CGCD) and 2(nd) order kinetics.

  4. Glass beads and Ge-doped optical fibres as thermoluminescence dosimeters for small field photon dosimetry.

    PubMed

    Jafari, S M; Alalawi, A I; Hussein, M; Alsaleh, W; Najem, M A; Hugtenburg, R P; Bradley, D A; Spyrou, N M; Clark, C H; Nisbet, A

    2014-11-21

    An investigation has been made of glass beads and optical fibres as novel dosimeters for small-field photon radiation therapy dosimetry. Commercially available glass beads of largest dimension 1.5 mm and GeO2-doped SiO2 optical fibres of 5 mm length and 120 µm diameter were characterized as thermoluminescence dosimeters. Results were compared against Monte-Carlo simulations with BEAMnrc/DOSXYZnrc, EBT3 Gafchromic film, and a high-resolution 2D-array of liquid-filled ionization chambers. Measurements included relative output factors and dose profiles for square-field sizes of 1, 2, 3, 4, and 10 cm. A customized Solid-Water® phantom was employed, and the beads and fibres were placed at defined positions along the longitudinal axis to allow accurate beam profile measurement. Output factors and the beam profile parameters were compared against those calculated by BEAMnrc/DOSXYZnrc. The output factors and field width measurements were found to be in agreement with reference measurements to within better than 3.5% for all field sizes down to 2 cm2 for both dosimetric systems, with the beads showing a discrepancy of no more than 2.8% for all field sizes. The results confirm the potential of the beads and fibres as thermoluminescent dosimeters for use in small photon radiation field sizes.

  5. Effect of gamma irradiation on opto-structural, dielectric, and thermoluminescence properties of natural phlogopite mica

    SciTech Connect

    Kaur, Sukhnandan; Singh, Surinder; Singh, Lakhwant; Lochab, S. P.

    2013-09-07

    Gamma ray induced modifications in natural phlogopite mica have been studied in the dose range of 1–2000 kGy. These modifications were monitored using different techniques viz: ultraviolet-visible spectroscopy, Fourier Transform Infrared spectroscopy, dielectric measurements, X-ray diffraction, and thermoluminescence dosimeter. The analysis of the results reveals that the dose of 100 kGy produces significant change in the natural phlogopite mica as compared to pristine and other exposed samples. Ultraviolet-visible analysis provides the value of optical indirect, direct band gap, and Urbach energy. Cody model was used to calculate structural disorder from Urbach energy. Different dielectric parameters such as dielectric constant, dielectric loss, ac conductivity, and real and imaginary parts of electric modulus were calculated for pristine and irradiated samples at room temperature. Williamson Hall analysis was employed to calculate crystallite size and micro-strain of pristine and irradiated sheets. No appreciable changes in characteristic bands were observed after irradiation, indicating that natural phlogopite mica is chemically stable. The natural phlogopite mica may be recommended as a thermoluminescent dosimeter for gamma dose within 1 kGy–300 kGy.

  6. Synthesis and thermoluminescence properties of rare earth-doped NaMgBO3 phosphor.

    PubMed

    Khan, Z S; Ingale, N B; Omanwar, S K

    2016-05-01

    Rare earth (Dy(3+) and Sm(3+))-doped sodium magnesium borate (NaMgBO3) is synthesized by solution combustion synthesis method keeping their thermoluminescence properties in mind. The reaction produced very stable crystalline NaMgBO3:RE (RE = Dy(3+), Sm(3+)) phosphors. The phosphors are exposed to (60)Co gamma-ray radiations dose of varying rate from 5 to 25 Gy, and their TL characteristics with kinetic parameters are studied. NaMgBO3:Dy(3+) phosphor shows two peaks for lower doping concentration of Dy(3+) while it reduced to single peak for the higher concentrations of activator Dy(3+). NaMgBO3:Dy(3+) shows the major glow peak around 200 °C while NaMgBO3:Sm(3+) phosphors show two well-separated glow peaks at 200 and 332 °C respectively. The thermoluminescence intensity of these phosphors was compare with the commercially available TLD-100 (Harshaw) phosphor. The TL responses for gamma-ray radiations dose were found to be linear from 5 to 25 Gy for both phosphors while the fading in each case is calculated for the tenure of 45 days.

  7. Photoluminescence and thermoluminescence investigations of Ca3B2O6: Sm3+ phosphor

    NASA Astrophysics Data System (ADS)

    Manhas, M.; Kumar, Vinay; Ntwaeaborwa, O. M.; Swart, H. C.

    2015-07-01

    Sm3+ doped Ca3B2O6 phosphors have been synthesized by combustion method. X-ray diffraction (XRD), photoluminescence (PL), UV-Vis spectroscopy and thermoluminescence (TL) have been used to study the structural, luminescence and optical properties of the phosphors. Under 400 nm excitation, the phosphor shows characteristic emission for Sm3+ ion (4G5/2 → 6Hj/2, j = 5, 7, 9 and 11) with the main orange-red emission peak at 600 nm corresponding to the 4G5/2 → 6H7/2 transition state of the Sm3+ ion. The optimum molar concentration and maximum critical distance between the Sm3+- Sm3+ ions were found to be 3 mol.% and 20.098 Å, respectively. The phosphor can be efficiently excited by near UV chips for their potential use in solid state lighting. The calculated CIE coordinates (0.60, 0.40) were found to be in the orange-red spectrum region. The thermoluminescence studies were carried out after irradiating the phosphor by gamma rays in the dose range of 10-5000 Gy. The glow peak was deconvoluted by the TLAnal program and the kinetic parameters associated with the deconvoluted peaks were evaluated.

  8. Feasibility study of CaSO4:Tb,Yb as a thermoluminescent dosimeter

    NASA Astrophysics Data System (ADS)

    Junot, Danilo O.; Santos, Max A.; Chagas, Marcos A. P.; Couto dos Santos, Marcos A.; Nunes, Luiz A. O.; Souza, Divanizia N.

    2014-02-01

    A new composite based on CaSO4, using terbium as dopant and ytterbium as co-dopant (CaSO4:Tb,Yb), was developed for employment as a thermoluminescent (TL) dosimeter. The crystals used in this work were grown using a production route based on the Yamashita method (Yamashita et al., 1968). Crystal powder was calcined at 600 °C for 1 h. Pellets were made by adding commercial and colorless glass to improve physical resistance and sintered at 700 °C for 6 h. All samples were irradiated by a beta source (90Sr/90Y) and received doses from 1 Gy to 5 Gy. TL analyses have been performed and characteristics such as sensitivity, reproducibility, linearity, and fading have been studied. The CaSO4:Tb,Yb pellets glow curves presented two peaks, the first at around 115 °C, and the second at around 200 °C. The highest intensity was shown for CaSO4:Tb,Yb with a concentration of 0.1 mol% of Tb and Yb together. In all the samples the TL response was proportional to the absorbed dose. Therefore, the CaSO4:Tb,Yb has potential to be used as a thermoluminescent dosimeter.

  9. Sensitive Fibre-Based Thermoluminescence Detectors for High Resolution In-Vivo Dosimetry

    PubMed Central

    Ghomeishi, Mostafa; Mahdiraji, G. Amouzad; Adikan, F. R. Mahamd; Ung, N. M.; Bradley, D. A.

    2015-01-01

    With interest in the potential of optical fibres as the basis of next-generation thermoluminescence dosimeters (TLDs), the development of suitable forms of material and their fabrication has become a fast-growing endeavour. Present study focuses on three types of Ge-doped optical fibres with different structural arrangements and/or shapes, namely conventional cylindrical fibre, capillary fibre, and flat fibre, all fabricated using the same optical fibre preform. For doses from 0.5 to 8 Gy, obtained at electron and photon energies, standard thermoluminescence (TL) characteristics of the optical fibres have been the subject of detailed investigation. The results show that in collapsing the capillary fibre into a flat shape, the TL yield is increased by a factor of 5.5, the yield being also some 3.2 times greater than that of the conventional cylindrical fibre fabricated from the same perform. This suggests a means of production of suitably sensitive TLD for in-vivo dosimeter applications. Addressing the associated defects generating luminescence from each of the optical fibres, the study encompasses analysis of the TL glow curves, with computerized glow curve deconvolution (CGCD) and 2nd order kinetics. PMID:26314683

  10. A Model for Collaborative Laboratory Experiences between Higher Education and a High School Technical Preparation Program: Promoting Higher Education, Mentoring, and Research

    ERIC Educational Resources Information Center

    Otterstetter, Ronald; Buser, Stacey; Kappler, Rachele; Herold, Kelly; Mullet, Nicole; Mullins, Nicole

    2011-01-01

    The Department of Sport Science and Wellness Education (SSWE) and the Athletic Health Care Technical Preparation (Tech Prep) Program (AHCTP) at The University of Akron (UA) are successfully fostering collaboration among a number of different entities (faculty members, allied health professionals, and undergraduate, graduate, and high school…

  11. Thermoluminescence properties of Mn-doped CaYAl3O7 phosphor irradiated with ultra-violet, mega-voltage and gamma radiation

    NASA Astrophysics Data System (ADS)

    Pathak, Pushpraj; Selot, Anupam; Kurchania, Rajnish

    2014-06-01

    Low temperature combustion synthesis was employed for the preparation of CaYAl3O7(Mn2+) phosphor. X-Ray diffraction (XRD) patterns were recorded to confirm the phase formation. Estimated particle size was found to be ~19.9 nm by using the Debye Scherrer's formula. FTIR study confirms the formation of CaYAl3O7 compound, escape of nitrates and other organic products. Thermoluminescence (TL) glow curves of the prepared phosphor were recorded after exposing the sample with Ultra-violet (UV), 6-Mega-voltage (MV), 16-MV and Co-60(Cobalt-60, 1.25-MeV average gamma energy) radiation. Trapping parameters namely activation energy (E), order of kinetics (b) and frequency factor(s) of main peak, centered around 186 °C in the sample irradiated with UV source for 20 min, were determined using glow curve shape (Chen's) method. It has been observed that the TL peak intensity increases with increasing the exposure from UV source. Also with increases the energy of incident radiation a decrease in TL peak intensity were observed. This could be due to higher penetration power and less absorbance of incident beam in the phosphor material. Analysis suggests that possibility of utilizing this phosphor in futuristic low and high energy dosimetric applications as well as in solid state lighting devices.

  12. Structural characterization, EPR and thermoluminescence properties of Cd{sub 1−x}Ni{sub x}SiO{sub 3} nanocrystalline phosphors

    SciTech Connect

    Manjunatha, C.; Sunitha, D.V.; Nagabhushana, H.; Sharma, S.C.; Ashoka, S.; Rao, J.L.; Nagabhushana, B.M.; Chakradhar, R.P.S.

    2012-09-15

    Highlights: ► CdSiO{sub 3}:Ni{sup 3+} nanophosphorus have been prepared at much lower temperatures. ► Phosphors are well characterized by PXRD, TEM, FTIR and UV–Vis spectroscopy. ► EPR, thermo and photoluminescence properties were also reported. -- Abstract: Cd{sub 1−x}Ni{sub x}SiO{sub 3} (x = 1–7 mol%) nanophosphors have been prepared for the first time by the combustion method using oxylyldihydrizide as a fuel. Powder X-ray diffraction results confirm the formation of monoclinic phase. Scanning electron micrographs show that Ni{sup 2+} influences the porosity of samples. The optical energy gap is widened with increase of Ni{sup 2+} ion dopant. The electron paramagnetic resonance spectrum of Ni{sup 2+} ions in CdSiO{sub 3} exhibits a symmetric absorption at g = 2.343 and the site symmetry around Ni{sup 2+} ions is predominantly octahedral. The number of spins participating in resonance (N) and the paramagnetic susceptibility (χ) has been evaluated. The thermoluminescence intensity is found to increase up to ∼20 min ultra-violet exposure and thereafter, decrease with further increase of ultra-violet dose. The kinetic parameters such as activation energy (E), frequency factor (s) and order of kinetics was estimated using glow peak shape method and the results are discussed.

  13. Experimental Studies of Surface-Driven Capillary Flow in PMMA Microfluidic Devices Prepared by Direct Bonding Technique and Passive Separation of Microparticles in Microfluidic Laboratory-On Systems

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Subhadeep; Banerjee, J. P.; Mathur, Ashish; Tweedie, M.; McLaughlin, J. A.; Roy, Susanta Sinha

    2015-05-01

    Proper bonding technique is investigated to achieve leakage-free surface-driven capillary flow in polymethylmethacrylate (PMMA) microfluidic devices. SU-8-based silicon stamp is fabricated by maskless lithography. This stamp is used to produce PMMA microchannel structure by hot embossing lithography. A direct bonding technique is mainly employed for leakage-free sealing inside PMMA microfluidic devices. The effect of surface wettability on surface-driven capillary flow is also investigated in PMMA microfluidic devices. The separation of polystyrene microparticles in PMMA laboratory-on-a-chip systems is investigated with the reduction of separation time by air dielectric barrier discharge (DBD) plasma processing of channel surfaces. This study is useful to fabricate the microfluidic laboratory-on-a-chip systems and to understand the surface-driven capillary flow.

  14. Guidance document for the preparation of waste management plans for the Environmental Restoration Program at Oak Ridge National Laboratory. Environmental Restoration Program

    SciTech Connect

    Clark, C. Jr.

    1993-07-01

    A project waste management (WM) plan is required for all Oak Ridge National Laboratory (ORNL) Environmental Restoration (ER) Program remedial investigation, decommission and decontamination (D&D), and remedial action (RA) activities. The project WM plan describes the strategy for handling, packaging, treating, transporting, characterizing, storing, and/or disposing of waste produced as part of ORNL ER Program activities. The project WM plan also contains a strategy for ensuring worker and environmental protection during WM activities.

  15. Issues in the reconstruction of environmental doses on the basis of thermoluminescence measurements in the Techa riverside

    SciTech Connect

    Bougrov, N.G.; Degteva, M.O.; Goeksu, H.Y.; Meckbach, R.; Jacob, P.; Haskell, E.

    1998-12-01

    The potential of thermoluminescence measurements of bricks from the contaminated area of the Techa river valley, Southern Urals, Russia, for reconstructing external exposures of affected population groups has been studied. Thermoluminescence dating of background samples was used to evaluate the age of old buildings available on the river banks. The anthropogenic gamma dose accrued in exposed samples is determined by subtracting the natural radiation background dose for the corresponding age from the accumulated dose measured by thermoluminescence. For a site in the upper Techa river region, where the levels of external exposures were extremely high, the depth-dose distribution in bricks and the dependence of accidental dose on the height of the sampling position were determined. For the same site, Monte carlo simulations of radiation transport were performed for different source configurations corresponding to the situation before and after the construction of a reservoir on the river and evacuation of the population in 1956. A comparison of the results provides an understanding of the features of the measured depth-dose distributions and height dependencies in terms of the source configurations and shows that bricks from the higher sampling positions are likely to have accrued a larger fraction of anthropogenic dose from the time before the construction of the reservoir. The applicability of the thermoluminescent dosimetry method to environmental dose reconstruction in the middle Techa region, where the external exposure was relatively low, was also investigated.

  16. A THIN-LAYER LIF THERMOLUMINESCENCE DOSEMETER SYSTEM WITH FAST READOUT FOR THE USE IN PERSONAL DOSIMETRY SERVICES.

    PubMed

    Walbersloh, J; Busch, F

    2016-09-01

    A newly developed thermoluminescence dosemeter system is presented that is suitable for application in fields where personal monitoring of a large number of users is required. The system presented here is intended to be used as the upcoming main dosemeter for whole body dosimetry at the dosimetry service of the MPA NRW (Germany) with ∼110,000 evaluations per month.

  17. Issues in the reconstruction of environmental doses on the basis of thermoluminescence measurements in the Techa riverside

    NASA Technical Reports Server (NTRS)

    Bougrov, N. G.; Goksu, H. Y.; Haskell, E.; Degteva, M. O.; Meckbach, R.; Jacob, P.; Neta, P. I. (Principal Investigator)

    1998-01-01

    The potential of thermoluminescence measurements of bricks from the contaminated area of the Techa river valley, Southern Urals, Russia, for reconstructing external exposures of affected population groups has been studied. Thermoluminescence dating of background samples was used to evaluate the age of old buildings available on the river banks. The anthropogenic gamma dose accrued in exposed samples is determined by subtracting the natural radiation background dose for the corresponding age from the accumulated dose measured by thermoluminescence. For a site in the upper Techa river region, where the levels of external exposures were extremely high, the depth-dose distribution in bricks and the dependence of accidental dose on the height of the sampling position were determined. For the same site, Monte Carlo simulations of radiation transport were performed for different source configurations corresponding to the situation before and after the construction of a reservoir on the river and evacuation of the population in 1956. A comparison of the results provides an understanding of the features of the measured depth-dose distributions and height dependencies in terms of the source configurations and shows that bricks from the higher sampling positions are likely to have accrued a larger fraction of anthropogenic dose from the time before the construction of the reservoir. The applicability of the thermoluminescent dosimetry method to environmental dose reconstruction in the middle Techa region, where the external exposure was relatively low, was also investigated.

  18. Potential of a New Technique for Remote Sensing of Hydrocarbon Accumulations and Blind Uranium Deposits: Buried Lif Thermoluminescence Dosimeters

    NASA Technical Reports Server (NTRS)

    Siegel, F. R.; Vaz, J. E.; Lindholm, R. C.

    1982-01-01

    Buried thermoluminescence dosimeters may be useful in remote sensing of petroleum and natural gas accumulations and blind uranium deposits. They act as integrating detectors that smooth out the effects of environmental variations that affect other measuring systems and result in irregularities and poor repeatability in measurements made during gas and radiometric surveys.

  19. Application of thermoluminescence for detection of cascade shower 2: Detection of cosmic ray cascade shower at Mount Fuji

    NASA Technical Reports Server (NTRS)

    Akashi, M.; Kawaguchi, S.; Watanabe, Z.; Misaki, A.; Niwa, M.; Okamoto, Y.; Fujinaga, T.; Ichimura, M.; Shibata, T.; Dake, S.

    1985-01-01

    The results of a thermoluminescence (TL) chamber exposed at Mt. Fuji during Aug. '83 - Aug. '84 are reported. The TL signal induced by cosmic ray shower is detected and compared with the spot darkness of X-ray film exposed at the same time.

  20. Decommissioning of Active Ventilation Systems in a Nuclear R and D Facility to Prepare for Building Demolition (Whiteshell Laboratories Decommissioning Project, Canada) - 13073

    SciTech Connect

    Wilcox, Brian; May, Doug; Howlett, Don; Bilinsky, Dennis

    2013-07-01

    Whiteshell Laboratories (WL) is a nuclear research establishment owned by the Canadian government and operated by Atomic Energy of Canada Limited (AECL) since the early 1960's. WL is currently under a decommissioning license and the mandate is to remediate the nuclear legacy liabilities in a safe and cost effective manner. The WL Project is the first major nuclear decommissioning project in Canada. A major initiative underway is to decommission and demolish the main R and D Laboratory complex. The Building 300 R and D complex was constructed to accommodate laboratories and offices which were mainly used for research and development associated with organic-cooled reactors, nuclear fuel waste management, reactor safety, advanced fuel cycles and other applications of nuclear energy. Building 300 is a three storey structure of approximately 16,000 m{sup 2}. In order to proceed with building demolition, the contaminated systems inside the building have to be characterized, removed, and the waste managed. There is a significant focus on volume reduction of radioactive waste for the WL project. The active ventilation system is one of the significant contaminated systems in Building 300 that requires decommissioning and removal. The active ventilation system was designed to manage hazardous fumes and radioactivity from ventilation devices (e.g., fume hoods, snorkels and glove boxes) and to prevent the escape of airborne hazardous material outside of the laboratory boundary in the event of an upset condition. The system includes over 200 ventilation devices and 32 active exhaust fan units and high efficiency particulate air (HEPA) filters. The strategy to remove the ventilation system was to work from the laboratory end back to the fan/filter system. Each ventilation duct was radiologically characterized. Fogging was used to minimize loose contamination. Sections of the duct were removed by various cutting methods and bagged for temporary storage prior to disposition

  1. Patient Evaluation and Preparation in Vascular and Interventional Radiology: What Every Interventional Radiologist Should Know (Part 1: Patient Assessment and Laboratory Tests)

    SciTech Connect

    Taslakian, Bedros; Sebaaly, Mikhael Georges Al-Kutoubi, Aghiad

    2016-03-15

    Performing an interventional procedure imposes a commitment on interventional radiologists to conduct the initial patient assessment, determine the best course of therapy, and provide long-term care after the procedure is completed. After patient referral, contact with the referring physician and multidisciplinary team approach is vital. In addition, clinical history, physical examination, as well as full understanding of the pre-procedural laboratory results and imaging findings can guide the interventional radiologist to implement the most appropriate management plan, avoid unnecessary procedures, and prevent complications to achieve a successful outcome. We provide a comprehensive, methodical review of pre-procedural care and management in patients undergoing vascular and interventional radiology procedures.

  2. The Preparation of a UV-Light-Absorbing Polymer: A Project-Oriented Laboratory Experiment for the Introductory Organic Chemistry Curriculum

    NASA Astrophysics Data System (ADS)

    Poon, Thomas; McIntyre, Jean P.; Dorigo, Andrea; Davis, Drew J.; Davis, Matthew A.; Eller, Crystal F.; Eller, Leah R.; Izumi, Heather K.; Jones, Kenya M.; Kelley, Kurt H.; Massello, William; Melamed, Megan L.; Norris, Cynthia M.; Oelrich, Jeffrey A.; Pluim, Thomas A.; Poplawski, Sarah E.; St. Clair, Jason M.; Stokes, Matthew P.; Wheeler, Wells C.; Wilkes, Erin E.

    1999-11-01

    A laboratory experiment is described that combines organic synthesis, spectroscopy, and polymer chemistry and is suitable for the sophomore organic chemistry curriculum. In this three-week sequence, students synthesize and characterize the UV-absorber 2-(2',4'-dimethylbenzoyl)benzoic acid and incorporate it into films of polymethylmethacrylate. The project exposes students to a variety of techniques and topics including UV-vis, nuclear magnetic resonance and IR spectroscopy, free radical polymerization, vacuum filtration, use of a separatory funnel for extraction and washing, melting point determination, recrystallization, reflux, and Friedel-Crafts acylation.

  3. Thermoluminescence survey of 12 meteorites collected by the European 1988 Antarctic meteorite expedition to Allan Hills and the importance of acid washing for thermoluminescence sensitivity measurements

    NASA Technical Reports Server (NTRS)

    Benoit, P. H.; Sears, H.; Sears, D. W. G.

    1991-01-01

    Natural and induced thermoluminescence (TL) data are reported for 12 meteorites recovered from the Allan Hills region of Antarctica by the European field party during the 1988/1989 field season. The samples include one with extremely high natural TL, ALH88035, suggestive of exposure to unusually high radiation doses (i.e., low degrees of shielding), and one, ALH88034, whose low natural TL suggests reheating within the last 100,000 years. The remainder have natural TL values suggestive of terrestrial ages similar to those of other meteorites from Allan Hills. ALH88015 (L6) has induced TL data suggestive of intense shock. TL sensitivities of these meteorites are generally lower than observed falls of their petrologic types, as is also observed for Antarctic meteorites in general. Acid-washing experiments indicate that this is solely the result of terrestrial weathering rather than a nonterrestrial Antarctic-non-Antarctic difference. However, other TL parameters, such as natural TL and induced peak temperature-width, are unchanged by acid washing and are sensitive indicators of a meteorite's metamorphic and recent radiation history.

  4. Effective atomic numbers and mass attenuation coefficients of some thermoluminescent dosimetric compounds for total photon interaction

    SciTech Connect

    Shivaramu; Amutha, R.; Ramprasath, V.

    1999-05-01

    Effective atomic numbers for total gamma-ray interaction with some selected thermoluminescent dosimetric compounds such as barium acetate, barium sulfate, calcium carbonate, calcium sulfate, calcium sulfate dihydrate, cadmium sulfate (anhydrous), cadmium sulfate, strontium sulfate, and lithium fluoride have been calculated in the 1-keV to 20-MeV energy region. Experimental mass attenuation coefficients and effective atomic numbers for these compounds at selected photon energies of 26.3, 33.2, 59.54, and 661.6 keV have been obtained from good geometry transmission measurements and compared with theoretical values. The effect of absorption edge on effective atomic numbers and its variation with energy, and nonvalidity of the Bragg`s mixture rule at incident photon energies closer to the absorption edges of constituent elements of compounds are discussed.

  5. Characterizing thermoluminescence properties of calcium halophosphate fluorescent coating powder for radiation dosimetry.

    PubMed

    Inyang, E P; Taleatu, B A; Oketayo, O O; Mokobia, C E; Adenodi, R A; Balogun, E A

    2011-01-01

    The thermoluminescence (TL) and other properties of calcium halophosphate fluorescent coating powder were studied in detail with the sole aim of ascertaining its suitability for use as a dosimetric material. The shape of the glow curve (peaks at about 125 degrees C and 350 degrees C) as well as its fairly linear dose response even at very high doses are indicative of its suitability. Optical properties of the material were studied using Infrared spectroscopy (IR) and UV-Visible spectrophotometry. The IR spectrum shows a prominent peak at 3425.9 cm(-1) indicating the presence of OH and N-H bonds. The material absorbs sharply at wavelength between 196 nm and 220 nm. The material exhibits high transmittance at various peaks with corresponding wavelengths from 300 to 831 nm. This material can also find application in radiation therapy associated with very high accident dosimetry as well as in material testing.

  6. Dosimetric characteristics of ultraviolet and x-ray-irradiated KBr:Eu{sup 2+} thermoluminescence crystals

    SciTech Connect

    Melendrez, R.; Perez-Salas, R.; Aceves, R.; Piters, T.M.; Barboza-Flores, M.

    1996-08-01

    Thermoluminescence (TL) characteristics of KBr:Eu{sup 2+} (150 ppm) previously exposed to ultraviolet (UV) light (200{endash}300 nm) and x-ray radiation at room temperature have been determined. The TL glow curve of UV-irradiated samples is composed of six peaks located at 337, 384, 402, 435, 475, and 510 K. The TL glow curves of x-irradiated samples show mainly a TL peak around 384 K. The TL intensities of UV-irradiated (402 and 510 K glow peaks) and x-irradiated specimens present a linear dependence as a function of radiation dose as well as fading stability 300 s after irradiation. These results further enhance the possibilities of using europium-doped materials in nonionizing (actinic region) and ionizing radiation detection and dosimetry applications. {copyright} {ital 1996 American Institute of Physics.}

  7. Rare earth-doped nanocrystalline MgF2: Synthesis, luminescence and thermoluminescence

    NASA Astrophysics Data System (ADS)

    Jacobsohn, L. G.; Roy, A. L.; McPherson, C. L.; Kucera, C. J.; Oliveira, L. C.; Yukihara, E. G.; Ballato, J.

    2013-10-01

    The radioluminescence (RL) and thermoluminescence (TL) activation of MgF2 through the incorporation of rare earths is investigated in this work. These materials were obtained by ligand-free solution precipitation and calcination at 500 °C in air, and Ce, Eu and Tb were incorporated at the 1 mol% level. RL results of doped and undoped materials seem to indicate that the incorporation of rare earths creates effective luminescence centers, which is accompanied by an increase in the TL signal intensity in comparison with the undoped material. In particular, RL emission of MgF2:Ce is reported to be centered at 325 nm. The traps associated with the TL signal were found to be unstable under exposure to room light, suggesting potential for applications involving optically stimulated luminescence.

  8. Thermoluminescence and photoluminescence studies on gamma irradiated CsI : Pb2+ crystals

    NASA Astrophysics Data System (ADS)

    Selvasekarapandian, S.; Brahmanandhan, G. M.; Malathi, J.; Joseph, V.

    2006-09-01

    Pure and Pb2+-doped CsI crystals have been grown by the Bridgemann technique. Optical absorption, thermoluminescence (TL) and photoluminescence (PL) measurements have been performed. In undoped and Pb2+-doped cesium iodide crystals, F-centers and V-centers have been produced at 770 nm and 350 nm, respectively. In Pb2+-doped crystals, additional centers at 373 nm, 290 nm and 258 nm bands have been produced. In undoped samples, only two glow peaks at 343 K and 373 K have been produced, and in Pb2+-doped samples additional glow peaks at 383 K and 423 K have been produced. For all the samples, TL emission, PL and excitation measurements have been performed.

  9. Evaluation of Exposure From a Low Energy X-Ray Device Using Thermoluminescent Dosimeters

    NASA Technical Reports Server (NTRS)

    Edwards, David L.; Harris, William S., Jr.

    1997-01-01

    The exposure from an electron beam welding device was evaluated using thermoluminescent dosimeters (TLDs). The device generated low energy X-rays which the current dose equivalent conversion algorithm was not designed to evaluate making it necessary to obtain additional information relating to TLD operation at the photon energies encountered with the device. This was accomplished by performing irradiations at the National Institute of Standards and Technology (NIST) using low energy X-ray techniques. The resulting data was used to determine TLD badge response for low energy X-rays and to establish the relationship between TLD element response and the dose equivalent at specific depths in tissue for these photon energies. The new energy/dose equivalent calibration data was used to calculate the shallow and eye dose equivalent of badges exposed to the device.

  10. Analysis Of Zapotec Ceramics Of The Caxonos River Basin, Oaxaca, Mexico By Thermoluminescence (Tl)

    NASA Astrophysics Data System (ADS)

    Ramirez, A.; Schaaf, P.; Ortiz, E.

    One of the most common materials that appear in archaeological excavations is the ceramics. Ceramic is an evidence for different activities and cultural periods. Thermoluminescence (TL) has been shown to be a very effective method for dating of archaeological ceramics. In this paper, we present the results of 18 Zapotec ceramics from different archaeological sites of the Caxonos River Basin, Northern Sierra of Oaxaca, Mexico, analyzed by TL. Based on these results, we established the first chronological data set of this important Mesoamerica site. Our new data give evidence for the existence of a trade route through the Caxonos River Basin used since 500 AD between the central valley of Oaxaca and the Gulf of Mexico. Methodologically we used the fine grain technique (4-11μm) and for the determination of the paleodose the additive method was applied.

  11. Investigations of doses on board commercial passenger aircraft using CR-39 and thermoluminescent detectors.

    PubMed

    Horwacik, T; Bilski, P; Olko, P; Spurny, F; Turek, K

    2004-01-01

    Measurements of cosmic radiation dose rates (from the neutron and the non-neutron components) on board passenger aircraft were performed using environmental packages with thermoluminescent TL and CR-39 etched track detectors. The packages were calibrated at the CERN-EU high-energy Reference Field Facility and evaluated at the Institute of Nuclear Physics in Krakow (TL + CR-39) and at the German Aerospace Centre in Cologne (CR-39). Detector packages were exposed on board passenger aircraft operated by LOT Polish Airlines, flown between February and May 2001. The values of effective dose rate determined, averaged over the measuring period, ranged between 2.9 and 4.4 microSv h(-1). The results of environmental measurements agreed to within 10% with values calculated from the CARI-6 code.

  12. Mathematical study of the thermoluminescence process in K2YF5:Tb(3+).

    PubMed

    Kadari, Ahmed; Mostefa, Rabah; Marcazzó, Julián; Kadri, Dahane

    2015-12-01

    This paper presents results of studying the simulated thermoluminescence (TL) glow curve in potassium-yttrium double fluoride doped with trivalent optically active Tb(3+) ions (K2YF5:Tb(3+)). Samples have been irradiated with different doses (0.24, 2.4 and 24 Gy) of beta particles. Four trapping states and one kind of recombination-centre model have been used in this simulation. The activation energy and order of kinetics are determined using the general-order kinetic model. The results obtained using the authors' proposed models were tested and compared with the experimental glow curve of K2YF5:Tb(3+). The comparison has shown that the proposed model can predict more accurately and easily the behaviour of the TL glow curve at three different doses.

  13. Defect characterization in neodymium doped thallium indium disulfide crystals by thermoluminescence measurements

    NASA Astrophysics Data System (ADS)

    Delice, S.; Gasanly, N. M.

    2016-10-01

    Characteristics of defect centers in neodymium doped TlInS2 single crystals have been investigated in virtue of thermoluminescence measurements carried out at low temperatures (10-300 K) with various heating rates between 0.4 and 1.2 K s-1. One glow peak was detected with peak maximum temperature of 26 K at a rate of 0.4 K s-1. The observed glow peak was analyzed using three points and heating rate methods. The analysis results revealed the presence of one trap level with activation energy of 14 meV. Three points method showed that mixed order of kinetic dominates the trapping level. Shift of peak maximum temperature to higher values and decrease in TL intensity were observed as the heating rate was increased progressively. Distribution of traps was demonstrated using an experimental method based on illumination temperature varying between 10 and 14 K.

  14. Thermoluminescence and the shock and reheating history of meteorites. II - Annealing studies of the Kernouve meteorite

    NASA Technical Reports Server (NTRS)

    Sears, D. W. G.; Bakhtiar, N.; Keck, B. D.; Weeks, K. S.

    1984-01-01

    Samples of the unshocked, equilibrated chondrite, Kernouve (H6), have been annealed for 1-100 hours at 500-1200 C, their thermoluminescence sensitivity measured and Na, K, Mn, Ca, and Sc determined by instrumental neutron activation analysis. The TL sensitivity decreased with temperature until by 1000 C it had fallen by 40 percent. The process responsible has an activation energy of 8 kcal/mole and probably involves diffusion. Samples annealed 1000-1200 C had TL sensitivities 0.01 times the unannealed values, most of the decrease occurring at 1100 C. This process has an activation energy of 100 kcal/mole and is probably related to the melting of the TL phosphor, feldspar, with some decomposition and loss of Cs, Na and K. Meteorites whose petrography indicates heating above 1100 C by natural shock heating events (shock facies d-f), have TL sensitivities similar to samples annealed above 1100 C.

  15. Chemical and physical studies of type 3 chondrites. VIII - Thermoluminescence and metamorphism in the CO chondrites

    NASA Technical Reports Server (NTRS)

    Keck, Bradly D.; Sears, Derek W. G.

    1987-01-01

    A possible relationship between the thermoluminescence (TL) properties of CO chondrites and their metamorphic history was investigated by measuring the TL properties of seven normal CO chondrites and of the Colony and the Allan Hills A77307 (ALHA 77307) CO-related chondrites. With the exception of Colony and ALHA 77307, whose maximum induced TL emission is at approximately 350 C, the CO chondrites were found to exhibit two TL peaks: a 130 C and a 250 C peaks. Among the CO chondrites, the 130 C peak showed a 100-fold range in TL sensitivity and was found to correlate with various metamorphism-related phenomena, such as silicate heterogeneity, metal composition, and McSween's metamorphic subtypes. The peak at 250 did not show these correlations and, with exception of Colony, showed little variation.

  16. The natural thermoluminescence of meteorites. IV - Ordinary chondrites at the Lewis Cliff ice field

    NASA Technical Reports Server (NTRS)

    Benoit, Paul H.; Sears, Hazel; Sears, Derek W. G.

    1992-01-01

    Results of natural thermoluminescence (TL) measurements of 302 meteorites from the vicinity of the Lewis Cliff in the Beardmore region of Antarctica are presented in order to identify fragments of a single fall and to elucidate ice sheet movements and the mechanisms by which meteorite concentration occurs at this site. From the distribution of meteorites on the ice, the shape of the fields of 'paired' meteorites, and trends in the natural TL data, it is inferred that there is a western component to the movement of the ice at this location, as well as the previously supposed movement to the north. The western vector explains the concentration of meteorites along the western edge of the ice tongue. These new natural TL data identify several recent falls and several meteorites which probably had unusually small perihelia immediately prior to capture by the earth.

  17. Dosimetric characterization of a {sup 131}Cs brachytherapy source by thermoluminescence dosimetry in liquid water

    SciTech Connect

    Tailor, Ramesh; Ibbott, Geoffrey; Lampe, Stephanie; Bivens Warren, Whitney; Tolani, Naresh

    2008-12-15

    Dosimetry measurements of a {sup 131}Cs brachytherapy source have been performed in liquid water employing thermoluminescence dosimeters. A search of the literature reveals that this is the first time a complete set of dosimetric parameters for a brachytherapy ''seed'' source has been measured in liquid water. This method avoids the medium correction uncertainties introduced by the use of water-equivalent plastic phantoms. To assure confidence in the results, four different sources were employed for each parameter measured, and measurements were performed multiple times. The measured dosimetric parameters presented here are based on the AAPM Task Group 43 formalism. The dose-rate constant measured in liquid water was (1.063{+-}0.023) cGy h{sup -1} U{sup -1} and was based on the air-kerma strength standard for this source established by the National Institute of Standards and Technology. Measured values for the 2D anisotropy function and the radial dose function are presented.

  18. Kinetics and dosimetric features of secondary thermoluminescence in carbon-doped aluminium oxide

    NASA Astrophysics Data System (ADS)

    Chithambo, M. L.; Seneza, C.

    2014-04-01

    Carbon-doped aluminium oxide has some unstable electron traps whose presence is revealed as luminescence at temperatures close to ambient. Thermoluminescence of such a secondary glow peak at 46 °C has been studied for heating at 1.0 °C s-1. The study showed that the peak follows first order kinetics and has an activation energy of about 0.7 eV independent of irradiation. Its dose response is linear at low dose with a supralinearity index equal to 1 but suffers from fading between irradiation and measurement with a half-life of about 120 s. The luminescence is attributed to the 3P→1S transition at an F-centre.

  19. Irradiation of dates: insect disinfestation, microbial and chemical assessments, and use of thermoluminescence technique

    NASA Astrophysics Data System (ADS)

    Al-Kahtani, Hassan A.; M. Abu-Tarboush, Hamza; Al-Dryhim, Yousif N.; Ahmed, Mohamed A.; Bajaber, Adnan S.; Adam, El-Shami E.; El-Mojaddidi, Mohamed A.

    1998-08-01

    Irradiation of dates (Khalas variety) at 0.9 kGy was sufficient to eliminate single insect infestation ( Oryzaephilus surinamensis) and mixed infestation ( O. surinamensis and Tribolium castaneum), whereas 0.3 kGy was effective only in controlling single infestation. Sensory properties were not affected but irradiation contributed to some reduction in microbial counts immediately after irradiation and counts remained low till the end of 6 months storage period. All sugars were significantly reduced immediately after irradiation but they increased gradually with increasing storage time. Thermoluminescence (TL) technique was useful in discriminating between irradiated and unirradiated dates during the entire storage period but was less sensitive as far as the dose estimation is concerned.

  20. Combustion synthesis and thermoluminescence in YAlO3:Dy3+

    NASA Astrophysics Data System (ADS)

    Dhadade, I. H.; Moharil, S. V.; Dhoble, S. J.; Rahangdale, S. R.

    2016-05-01

    In the Y2O3-Al2O3 system, compounds Y3Al5O12 (yttrium aluminum garnet, YAG),YAlO3 (yttrium aluminum perovskite, YAP), and Y4Al2O9(yttrium aluminate monoclinic, YAM) are well known. Though several soft chemical routes have been explored for synthesis of YAG, YAP and YAM, most of these methods are complex. Moreover, phase pure materials are not obtained in one step and prolonged annealing at temperatures around 1000°C is necessary. In this paper, one step combustion synthesis of the compound YAlO3:Dy3+ is reported using a modified procedure and employing mixed (glycine + urea) fuel. Powder X-ray diffraction patterns confirm the pervoskite phase of YAlO3. Thermoluminescence study shows linear response in wide dose range (0.2 - 1 KGy) suggest the possibility of the present phosphor in dosimeter application.

  1. Thermoluminescence response of calcic bentonite subjected to conditions of high nuclear waste underground storage.

    PubMed

    Dies, J; Miralles, L; Tarrasa, F; Pueyo, J J; de las Cuevas, C

    2002-01-01

    Bentonite is regarded as a backfilling material for underground storage facilities of highly radioactive nuclear waste built on granite formations. In these facilities, bentonite will be subjected to a gradient of temperature and dose rate, achieving a very high integrated dose and, therefore, changes in its structure and physical properties may take place. Two experiments to discriminate between the thermal and the irradiation effect were performed. In the first (named BIC 2A), samples were subjected to temperature while in the second (named BIC-2B) the combined effect of temperature and irradiation was studied. The experimental conditions were: a thermal gradient between 130 degrees C and 90 degrees C, a maximum dose rate of 3.5 kGy.h(-1) and a gradient of the integrated dose between 1.75 MGy and 10 MGy. Both experiments lasted a total of 124 days. An irradiation source of 60Co with an activity close to 300,000 Ci, and bentonite samples of 200 mm in length and 50 mm in diameter were used. After the experiment, the samples were ground and two fractions were obtained: a fine fraction (<2 microm) enriched in montmorillonite clay mineral and a coarse fraction (>80 microm). The results are described of thermoluminescence analyses on the two fractions obtained which showed that the coarse fraction can be 100 times more sensitive to radiation than the fine fraction. On the other hand, the heated and irradiated samples showed a thermoluminescence response around 50 times greater than the samples that were only heated. In addition to this, the temperature and dose rate conditions are relevant parameters in the generation and stabilisation of radiation induced defects. Finally, the response of samples heated and irradiated for two months was quite similar to that obtained on samples heated and irradiated for four months, indicating a saturation phenomenon.

  2. The Sutter's Mill meteorite: Thermoluminescence data on thermal and metamorphic history

    NASA Astrophysics Data System (ADS)

    Sears, Derek W.; Beauford, Robert

    2014-11-01

    A piece of the Sutter's Mill meteorite, fragment SM2-1d, has been examined using thermoluminescence techniques to better understand its thermal and metamorphic history. The sample had very weak but easily measureable natural and induced thermoluminescence (TL) signals; the signal-to-noise ratio was better than 10. The natural TL was restricted to the high-temperature regions of the glow curve suggesting that the meteorite had been heated to approximately 300 °C within the time it takes for the TL signal to recover from a heating event, probably within the last 105 years. It is possible that this reflects heating during release from the parent body, close passage by the Sun, or heating during atmospheric passage. Of these three options, the least likely is the first, but the other possibilities are equally likely. It seems that temperatures of approximately 300 °C reached 5 or 6 mm into the meteorite, so that all but one of the small Sutter's Mill stones have been heated. The Dhajala normalized induced TL signal for SM2-1d is comparable to that of type 3.0 chondrites and is unlike normal CM chondrites, the class it most closely resembles, which do not have detectable TL sensitivity. The shape of the induced TL curve is comparable to other low-type ordinary, CV, and CO chondrites, in that it has a broad hummocky structure, but does not resemble any of them in detail. This suggests that Sutter's Mill is a unique, low-petrographic-type (3.0) chondrite.

  3. Thermoluminescence response of K2YF5:Tb3+ crystals to photon radiation fields.

    PubMed

    Faria, L O; Lo, D; Kui, H W; Khaidukov, N M; Nogueira, M S

    2004-01-01

    This investigation has been performed to test the feasibility of using K2YF5:Tb3+ crystals as thermoluminescence dosemeters (TLD). K2YF5 single crystals doped with 0.2, 10.0 and 50.0 at.% of trivalent optically active Tb3+ ions as well as K2TbF5 and undoped K2YF5 crystals have been synthesized under hydrothermal conditions. Polished crystal platelets with thickness of about 1 mm have been irradiated with X and gamma rays in order to study thermoluminescent (TL) sensitivity as well as dose and energy response in terms of the Tb3+ concentration in K2YF5. Within this concentration series, K2YF5 crystals doped with 10.0 at.% Tb3+ have been found to have maximum TL response due to a broad asymmetric TL glow peak at 269 degrees C with good linearity of dose response and reproducibility of dose measurements. After deconvolution, the main dosimetric peak has been revealed to be composed of two individual peaks, both with linear TL response behaviour, centered at 210 and 269 degrees C. As it has been proved, the linear TL signal coefficient for K2Y0.9Tb0.1F5 is almost 10 times greater than that for commercial TLD-100 (LiF:Mg,Ti), irradiated with a 137Cs gamma radiation source at the same conditions. The reported results indicate that K2YF5 crystals doped with Tb3+ have potential as promising materials for radiation dosemeters.

  4. Thermoluminescent characteristics of topaz from Sabser mine near Sakardu in northern Pakistan

    NASA Astrophysics Data System (ADS)

    Sardar, M.; Tufail, M.

    2011-02-01

    Topaz, a naturally occurring aluminium fluorosilicate mineral, shows thermo-luminescence (TL) after irradiation to gamma rays. The TL characteristics (glow curve, dose response/intensity, sensitivity, energy response, fading, reusability and mechanical stability) of topaz collected from the Sabser mine in the vicinity of Sakardu in northern Pakistan were studied. The purpose of this study was to design and develop a TLD (thermoluminescence dosimeter) based on topaz. The samples of topaz from this mine were cut into square chips of dimensions 3.2 × 3.2 mm with thickness 0.9 mm, which are suitable for the TLD reader. Gamma dose was given to the chips from 60Co and/or 137Cs gamma irradiators. The TL glow curves of the chips revealed stable peak at about 260 °C. The height of this peak rose linearly with increase of dose levels. The TL response versus dose (calibration curve) showed the linear behaviour between 10 -2 and 10 2 Gy without saturation. Dose response was independent of gamma energies of 60Co and 137Cs. The response of standard sized chips of topaz remained constant within ±11% deviation from initial value after 30 cycles of reuse. The rate of fading of topaz chips of this mine were studied up to four months, which was fast for initial few hours and slowed after a few days. The chips remained mechanically stable during handling in all types of experiments. Standard sized topaz chips of Sabser mine can effectively and efficiently be used as a TLD.

  5. Thermoluminescence studies on {gamma}-irradiated Mn:Li{sub 2}B{sub 4}O{sub 7} single crystals

    SciTech Connect

    Kar, S.; Debnath, C.; Verma, S.; Bartwal, K. S.; Bairagi, S.

    2012-08-13

    Manganese doped Li{sub 2}B{sub 4}O{sub 7} (LTB) crystals were grown by Czochralski technique and various kinetic parameter of thermoluminescence (TL) were measured. Crystals were irradiated with different {gamma}-dose using Co{sup 60} source. Thermoluminescence curves were recorded at various heating rates. Trap depth and frequency factor were calculated. Fading of Mn: Li{sub 2}B{sub 4}O{sub 7} was found only {approx}5%-6% in 6 months. Thermoluminescence intensity of Mn: Li{sub 2}B{sub 4}O{sub 7} was found highly sensitive to the mass of the material, and it varies abruptly with mass change of +/- 1 mg, irradiated with the same dose. Therefore, the accuracy in mass is important parameter for thermoluminescence dosimeter badge.

  6. CaSO4:DY,Mn: A new and highly sensitive thermoluminescence phosphor for versatile dosimetry

    NASA Astrophysics Data System (ADS)

    Bahl, Shaila; Lochab, S. P.; Kumar, Pratik

    2016-02-01

    With the advent of newer techniques for dose reduction coupled with the development of more sensitive detectors, the radiation doses in radiological medical investigation are decreasing. Nevertheless, keeping the tenet in mind that all radiation doses could entail risk, there is a need to develop more sensitive dosimeters capable of measuring low doses. This paper gives the account of the development of a new and sensitive phosphor CaSO4:Dy,Mn and its characterization. The standard production procedure based on the recrystallization method was used to prepare CaSO4:Dy,Mn. The Thermoluminescence (TL) studies were carried out by exposing it with gamma radiation (Cs-137) from 10 μGy to 100 Gy. The theoretical studies to determine the number of peaks and kinetic parameters related to the TL glow peaks in CaSO4:Dy,Mn was performed using the Computerized Glow Curve Deconvolution (CGCD) method. Experiments were performed to determine optimum concentration of the dopants Dysprosium (Dy) and Mangnese (Mn) in the host CaSO4 so that maximum sensitivity of the phosphor may be achieved. The optimum dopant concentration turned out to be 0.1 mol%. As there were two dopants Dy and Mn their relative ratio were varied in steps of 0.025 keeping the concentration of total dopant (Dy and Mn) 0.1 mol% always. The maximum TL intensity was seen in the CaSO4:Dy(0.025),Mn(0.075) combination. The TL sensitivity of this phosphor was found to be about 2 and 1.8 times higher than that of popular phosphor CaSO4:Dy and LiF:Mg,Cu,P (TLD-700H) respectively. This new phosphor CaSO4:Dy,Mn showed fading of 11% which is similar to that of the standard phosphor CaSO4:Dy. The paper concludes that the new, highly sensitive TL phosphor CaSO4:Dy,Mn has shown higher sensitivity and hence the potential to replace commonly used CaSO4:Dy.

  7. Photoluminescence and thermoluminescence of K2 Mg(SO4 )2 :Eu and evaluation of its kinetic parameters.

    PubMed

    Deshpande, Archana; Dhoble, N S; Gedam, S C; Dhoble, S J

    2016-12-02

    The K2 Mg(SO4 )2 :Eu phosphor, synthesized by a solid-state diffusion method, was studied for its photoluminescence (PL) and thermoluminescence (TL) characteristics. The X-ray diffraction (XRD) pattern of the material was matched with the standard JCPDF No. 36-1499. For PL characteristics, K2 Mg(SO4 )2 :Eu(2)(+) showed an emission peak at 474 nm when excited at 340 nm, while it showed Eu(3)(+) emission at 580 nm, and 594 nm splitting at 613 nm and 618 nm for an excitation of 396 nm wavelength due to radiative transitions from (5) D0 to (7) Fj (j = 0, 1, 2, 3). The Commission International de I' Eclairage (CIE) chromaticity coordinates were also calculated for the K2 Mg(SO4 )2 :Eu phosphor, and were close to the NTSC standard values. For the TL study, the prepared sample was irradiated using a (60) Co source of γ-irradiation at the dose rate of 0.322 kGy/h for 2 min. The formation of traps in K2 Mg (SO4 )2 :Eu and the effects of γ-radiation dose on the glow curve are discussed. Well defined broad glow peaks were obtained at 186°C. With increasing γ-ray dose, the sample showed linearity in intensity. The presence of a single glow peak indicated that there was only one set of traps being activated within the particular temperature range. The presented phosphors were also studied for their fading, reusability and trapping parameters. There was just 2% fading during a period of 30 days, indicating no serious fading problem. Kinetic parameters were calculated using the initial rise method and Chen's half-width method. Activation energy and frequency factor were found to be 0.77 eV and 1.41 × 10(6)  sec(-1) .

  8. In situ synchrotron X-ray powder diffraction for studying the role of induced structural defects on the thermoluminescence mechanism of nanocrystalline LiF.

    PubMed

    El Ashmawy, Mostafa; Amer, Hany; Abdellatief, Mahmoud

    2016-03-01

    The correlation between the thermoluminescence (TL) response of nanocrystalline LiF and its microstructure was studied. To investigate the detailed TL mechanism, the glow curves of nanocrystalline LiF samples produced by high-energy ball-milling were analyzed. The microstructure of the prepared samples was analyzed by synchrotron X-ray powder diffraction (XRPD) at room temperature. Then, the microstructure of a representative pulverized sample was investigated in detail by performing in situ XRPD in both isothermal and non-isothermal modes. In the present study, the dislocations produced by ball-milling alter the microstructure of the lattice where the relative concentration of the vacancies, responsible for the TL response, changes with milling time. An enhancement in the TL response was recorded for nanocrystalline LiF at high-temperature traps (after dislocations recovery starts >425 K). It is also found that vacancies are playing a major role in the dislocations recovery mechanism. Moreover, the interactions among vacancies-dislocations and/or dislocations-dislocations weaken the TL response.

  9. Fracto-mechanoluminescence and thermoluminescence properties of UV and γ-irradiated Ca₂Al₂SiO₇:Ce³⁺ phosphor.

    PubMed

    Tiwari, Geetanjali; Brahme, Nameeta; Sharma, R; Bisen, D P; Sao, Sanjay Kumar; Singh, Manisha

    2016-05-01

    Ce(3+)-doped calcium aluminosilicate phosphor was prepared by a combustion-assisted method at an initiating temperature of 600°C. Structural characterization was carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The absorption spectra of Ca2Al2SiO7:Ce(3+) showed an absorption edge at 230 nm. The optical characterization of Ca2Al2SiO7:Ce(3+) phosphor was investigated in a fracto-mechanoluminescence (FML) and thermoluminescence (TL) study. The peak of ML intensity increased as the height of impact of the moving piston increased. The TL intensity of Ca2Al2SiO7:Ce(3+) was recorded for different exposure times of UV and γ-irradiation and it was observed that TL intensity was maximum for a UV irradiation time of 30 min and for a γ-dose of 1180 Gy. The TL intensity had three peaks for UV irradiation at temperatures 82°C, 125°C and 203°C. Also the TL intensity had a single peak at 152°C for γ-irradiation. The TL and ML emission spectra of Ca2Al2SiO7:Ce(3+) phosphor showed maximum emission at 400 nm. The possible mechanisms involved in the TL and ML processes of the Ca2Al2SiO7:Ce(3+) phosphor are also explained.

  10. Effect of particle size on activation energy and peak temperature of the thermoluminescence glow curve of undoped ZnS nanoparticles.

    PubMed

    Chandra, B P; Chandrakar, Raju Kumar; Chandra, V K; Baghel, R N

    2016-03-01

    This paper reports the effect of particle size on the thermoluminescence (TL) of undoped ZnS nanoparticles. ZnS nanoparticles were prepared using a chemical precipitation method in which mercaptoethanol was used as the capping agent. The nanoparticles were characterized by X-ray diffraction, field emission gun-scanning electron microscopy and high-resolution transmission electron microscopy. When the concentrations of mercaptoethanol used are 0, 0.005, 0.01, 0.015, 0.025, 0.040 and 0.060 M, the sizes of the nanoparticles are 2.86, 2.81, 2.69, 2.40, 2.10, 1.90 and 1.80 nm, respectively. Initially, the TL intensity of UV-irradiated ZnS nanoparticles increases with temperature, attains a peak value Im for a particular temperature Tm, and then decreases with further increases in temperature. The values of both Im and Tm increase with decreasing nanoparticle size. Whereas the activation energy decreases slightly with decreasing nanoparticle size, the frequency factor decreases significantly as the nanoparticle size is reduced. The order of kinetics for the TL glow curve of ZnS nanoparticles is 2. Expressions are derived for the dependence of activation energy (Ea) and Tm on nanoparticle size, and good agreement is found between the experimental and theoretical results.

  11. [Comparative analysis of 3D data visibility of the prepared tooth finishing line on a synthetic jaw model, captured by international scanners in a laboratory conditions].

    PubMed

    Ryakhovsky, A N; Kostyukova, V V

    The aim of the study was to compare accuracy of digital impression's finishing line and the zone under it taken by different intraoral scanning systems. Parameters of comparison were: different level of the finishing line to the gingiva and width of sulcus after retraction. For this purpose two synthetic jaw models with prepared teeth were scanned using intraoral scanning systems: 3D Progress (MHT S.P.A., IT - MHT Optic Research AG, CH); True Definition (3M ESPE, USA); Trios (3Shape A/S, DNK); CEREC AC Bluecam, CEREC Omnicam (Sirona Dental System GmbH, DE); Planscan (Planmeca, FIN) (each n=10). Reference-scanning was done by ATOS Core (GOM mbH, DE). The resulting digital impressions were superimposed with the master-scan. The lowest measured deviations (trueness) for intraoral scanners, where the finishing line was 0.5 mm above gingiva were with scanner True Definition - 18.8±6.63 (on the finishing line) and 51.0±14.33 µm (0.3 mm under the finishing line). In conditions where finishing line was on the same level with gingiva, scanner Trios showed the best results: 17.0±3.96 and 52.7±6.52 µm. When the finishing line was 0.5 mm under gingiva, none of the testing scanners could visualize the zone 0.3 mm lower the finishing line. The best results for accuracy o the finishing line in that circumstances showed Trios: 15.1±5.05 µm. The optimum visualization of the finishing line and the zone under it was reached when the sulcus was 0.3 mm after retraction. Thus, the best accuracy was obtained with Trios: 10.3±2.69 (on the finishing line) and 57.2±13.58 µm (0.3 mm under finishing line). The results show that intraoral scanners also provide enough accuracy for indicating finishing line and the zone under it in different conditions of preparation and gingiva retraction. However, not all of the testing scanners can properly indicate finishing line and the zone under it when shoulder is below gingiva and the width of sulcus is less than 0.2 mm.

  12. Preparation of tamarind fruit seed activated carbon by microwave heating for the adsorptive treatment of landfill leachate: A laboratory column evaluation.

    PubMed

    Foo, K Y; Lee, L K; Hameed, B H

    2013-04-01

    The preparation of tamarind fruit seed granular activated carbon (TSAC) by microwave induced chemical activation for the adsorptive treatment of semi-aerobic landfill leachate has been attempted. The chemical and physical properties of TSAC were examined. A series of column tests were performed to determine the breakthrough characteristics, by varying the operational parameters, hydraulic loading rate (5-20 mL/min) and adsorbent bed height (15-21 cm). Ammonical nitrogen and chemical oxygen demand (COD), which provide a prerequisite insight into the prediction of leachate quality was quantified. Results illustrated an encouraging performance for the adsorptive removal of ammonical nitrogen and COD, with the highest bed capacity of 84.69 and 55.09 mg/g respectively, at the hydraulic loading rate of 5 mL/min and adsorbent bed height of 21 cm. The dynamic adsorption behavior was satisfactory described by the Thomas and Yoon-Nelson models. The findings demonstrated the applicability of TSAC for the adsorptive treatment of landfill leachate.

  13. Evaluation and comparison of the effect of different surface preparations on bond strength of glass ionomer cement with nickel-chrome metal-ceramic alloy: a laboratory study.

    PubMed

    Hasti, Kalpana; Jagadeesh, H G; Patil, Narendra P

    2011-03-01

    Retention of fixed partial dentures is mostly dependent upon the bond between metal and cement as well as cement and tooth structure. However, most of the time clinical failure of bond has been observed at metal and cement interface. The treatment of metal surface, prior to luting, plays a crucial role in bonding cement with the metal. This study is conducted to evaluate and compare the effect of different surface preparations on the bond strength of resin-modified glass ionomer cement with nickel-chromium metal ceramic alloy. Fifty caries-free extracted molar teeth were made flat until the dentin of the occlusal surface was exposed. After fabrication of the wax patterns and subsequent castings, the castings were subjected to porcelain firing cycles. The nickel-chromium metal ceramic alloy discs were also divided into five groups and subjected to various surface treatments: (1) Unsandblasted (U), (2) sandblasted (S), (3) sandblasted and treated with 10% aqueous solution of KMnO4 (SK), (4) unsandblasted and roughened with diamond abrasive points (UD) and (5) unsandblasted and roughened with diamond abrasive points and treated with 10% aqueous solution of KMnO(4) (UDK). After surface treatments, the castings were cemented using Fuji PLUS encapsulated resin-modified glass ionomer cement. The obtained values of all the groups were subjected to statistical analysis for Tensile and Shear bond strength. Different surface treatments of the metal affects the bond strength values of resin-modified glass ionomer cement when used as luting agent.

  14. Simulating Laboratory Procedures.

    ERIC Educational Resources Information Center

    Baker, J. E.; And Others

    1986-01-01

    Describes the use of computer assisted instruction in a medical microbiology course. Presents examples of how computer assisted instruction can present case histories in which the laboratory procedures are simulated. Discusses an authoring system used to prepare computer simulations and provides one example of a case history dealing with fractured…

  15. The calculation of mass attenuation coefficients of well-known thermoluminescent dosimetric compounds at wide energy range

    NASA Astrophysics Data System (ADS)

    Ermis, Elif Ebru

    2017-02-01

    The photon mass attenuation coefficients of LiF, BaSO4, CaCO3 and CaSO4 thermoluminescent dosimetric compounds at 100; 300; 500; 600; 800; 1,000; 1,500; 2,000; 3,000 and 5,000 keV gamma-ray energies were calculated. For this purpose, FLUKA Monte Carlo (MC) program which is one of the well-known MC codes was used in this study. Furthermore, obtained results were analyzed by means of ROOT program. National Institute of Standards and Technology (NIST) values were also used to compare the obtained theoretical values because the mass attenuation values of the used compounds could not found in the literature. Calculated mass attenuation coefficients were highly in accordance with the NIST values. As a consequence, FLUKA was successful in calculating the mass attenuation coefficients of the most used thermoluminescent compound.

  16. [New dosimetry system based on the thermoluminescence method for evaluation of ionizing radiation doses to workers of the health centers].

    PubMed

    Urban, Paweł; Skubacz, Krystian

    2015-01-01

    In different areas of industry, science and in the greater extend medicine, plenty of devices intended for production of ionizing radiation or containing sources of such radiation found application. Such situation causes the necessity to control such kind of hazards. Currently, the most popular technique for detection of ionizing radiation is the method based on the thermoluminescence phenomena. Within the frame of this work, a new Panasonic's dosimetry system based on thermoluminescence dosimeters, intended for assessment of doses in mixed radiation fields of various energies is presented. In addition, the measured dosimetry quantities and problems connected with monitoring of radiation hazard in mixed fields (commonly present in medical sector) are characterized. In orderto verify measurement capabilities of the new system the irradiations of dosimeters with ionizing radiation of different energies have been done.

  17. Laboratory Tests

    MedlinePlus

    Laboratory tests check a sample of your blood, urine, or body tissues. A technician or your doctor ... compare your results to results from previous tests. Laboratory tests are often part of a routine checkup ...

  18. A fading-based method for checking the presence of closely overlapping peaks in thermoluminescent (TL) materials

    NASA Astrophysics Data System (ADS)

    Furetta, C.

    The paper describes a method, based on fading experiment, for determining the presence of a complex structure in the thermoluminescent glow curve emission from herbs, e.g. oregano and nopal. Because of the polymineral content of the inorganic part of these herbs, the emitted glow curve is the result of several overlapping glow peaks, each one corresponding to another mineral. The initial rise method is also used for determining the activation energy of each component.

  19. Shock-thermal history of Kapoeta howardite matter on data of thermoluminescence analysis of individual mineral grains

    NASA Technical Reports Server (NTRS)

    Ivliev, A. I.; Kashkarov, L. L.; Korotkova, Yu. YU.

    1993-01-01

    The artificially induced thermoluminescence (TL) was measured in OPx grains from Kapoeta howardite. The TL glow curves for individual OPx grains are significantly distinguished from each other both by their shape and TL sensitivity; five groups of OPx grains were characterized. The observed variety of glow curves of OPx grains could be caused by their distinct shock-thermal events at the regolith stage of meteorite parent body formation.

  20. Detection threshold energy of high energy cascade showers using thermoluminescence PTFE-sheet and hot-gas reader

    NASA Technical Reports Server (NTRS)

    Kino, S.; Nakanishi, A.; Miono, S.; Kitajima, T.; Yanagita, T.; Nakatsuka, T.; Ohmori, N.; Hazama, M.

    1985-01-01

    A new thermoluminescence (TL) sheet was developed as a detector for high energy components in air showers. For the investigation of detection threshold energy for a cascade showeer, TL sheets were exposed at Mt. Fuji with X ray films in emulsion chambers and were scanned by a hot-gas reader. It is concluded that if a gamma ray whose energy is more than 6 TeV enters vertically into lead chambers, the resulting cascade shower is readily detectable at maximum development.

  1. High-pressure studies of photoluminescence and thermoluminescence of ZnS:Cu:Cl phosphors using laser selection excitation

    SciTech Connect

    Lang, J.M.; Dreger, Z.A.; Drickamer, H.G.

    1992-01-09

    The authors have measured the effect of pressure on the luminescence and thermoluminescence characteristics of three ZnS phosphors doped with Cu and Cl. The total dopant concentration varied in the ratio 1/1.5/2.5, but the Cl/Cu ratio was constant at {approximately}8/1. The excitation was via the 325-nm (3.82-eV) line of a He-Cd laser. The absorption edge of ZnS is at 3.67 eV at 1 atm and increases by 6.35 meV/kbar, so that at high pressure the excitation is to {open_quotes}deep levels{close_quotes} provided by the Cl. The emission consists of two peaks at 20,000 and 22,000 cm{sup {minus}1} assigned to emission from a Cl{sup {minus}} center to a Zn vacancy and a Cu{sup +} center, respectively. Both emission peaks increased in energy with pressure. The shifts could be explained in terms of the degree of pinning of donor and acceptor levels to the conduction and valence bands. The thermoluminescence data indicated an initial trap depth of 0.3 eV for all three samples. This trap depth increased with pressure at low pressures but leveled at 0.39, 0.46, and 0.54 eV for the high-, intermediate-, and low-concentration samples, respectively. The thermoluminescence intensity decreased by 2 orders of magnitude in 40 kbar. The behavior of the thermoluminescence could be explained largely by differences in the nature and behavior of the {open_quotes}deep levels{close_quotes} initially in the conduction band. 28 refs., 10 figs., 2 tabs.

  2. Intercomparison of environmental gamma doses measured with A NaI (Tl) survey meter and thermoluminescent dosimeters (TLDs) in the Poonch division of Azad Kashmir, Pakistan.

    PubMed

    Rafique, Muhammad; Kearfott, Kimberlee J; Ahmad, Khalil; Akhter, Jabeen; Khan, Abdul Razzaq; Saeed, Raja Azhar; Rahman, Saeed Ur; Matiullah; Rajput, Muhammad Usman

    2014-12-01

    This study presents the intercomparison of the outdoor environmental gamma dose rates measured using a NaI (Tl) based survey meter along with thermoluminescent dosimeters (TLDs) and estimation of excess lifetime cancer risk (ELCR), for the inhabitants of Poonch division of the Azad Kashmir, Pakistan. CaF2: Dy (TLD-200) card dosimeters were installed at height of 1 m from ground at fifteen different locations covering the entire Poonch division comprising of three districts. During three distinct two month time periods within the six month study period, all the installed dosimeters were exposed to outdoor environmental gamma radiations, retrieved and read out at Radiation Dosimetry Laboratory, Health Physics Division, PINSTECH laboratory, Islamabad. The ambient outdoor gamma dose rate measurements were also taken with NaI (Tl) based portable radiometric instrument at 1 m above the ground. To estimate the annual gamma doses, NaI (Tl) based survey data were used for one complete year following the deployment of the dosimeters. The mean annual gamma dose rates measured by TLDs and survey meter were found as 1.47±0.10 and 0.862±0.003 mGy/y respectively. Taking into account a 29% outdoor occupancy factor, the annual average effective dose rate for individuals was estimated as 0.298±0.04 and 0.175±0.03 mSv/y by TLDs and survey meter, respectively. For outdoor exposure, the ELCR was calculated from the TLD and survey meter measurements. The environmental outdoor average annual effective dose obtained in present study are less than the estimated world average terrestrial and cosmic gamma ray dose rate of 0.9 mSv/y reported in UNSCEAR 2000. The possible origins of gamma doses in the area and incompatibilities of results obtained from the two different measurement techniques are also discussed.

  3. Study of photoluminescence and thermoluminescence properties of BaAl2O4 (Eu2+, Dy3+) phosphor synthesized by solution combustion method

    NASA Astrophysics Data System (ADS)

    Pathak, Pushpraj; Kurchania, Rajnish

    2016-10-01

    Eu and Dy co-doped barium aluminate phosphor was successfully synthesized by combustion method using urea as a fuel. Phase formation was confirmed by powder X-ray diffraction (PXRD) analysis. The calculated average crystallite size was found to be ~34.62 nm. Scanning electron microscopy (SEM) images acquired at different (low and high) magnifications reveal that the crystallites have no uniform shape and size. This was due to the non-uniform distribution of temperature and mass flow in the combustion technique. Fourier Transform Infra-red (FTIR) spectrum was recorded to confirm the phase formation and also to identify any impurity if present in the prepared phosphor. Photoluminescence (PL) measurement was carried out to investigate the incorporation of dopant into the host lattice. Thermoluminescence (TL) behaviour of synthesized phosphor was studied after the irradiation with Cobalt-60 gamma rays (Eavg=1.25 MeV) as well as 6 and 16 MV (Mega Voltage) X-ray photons, at various dose levels. The glow curves of irradiated samples exhibit only one peak at 115 °C at each dose level. With the increases of radiation dose an increase in total intensity has been observed. No appreciable shift in peak positions has been observed. Trapping parameters were evaluated to understand the characteristics of prepared phosphor. A simple glow peak with relatively high intensity is one of the important factors, which make this phosphor useful for monitoring the ionizing radiations in nuclear industries, gamma irradiators, high energy accelerators, nuclear reactors etc. where medium and high level of exposure is involved. It could also be applicable for accidental and retrospective dose assessment.

  4. 30 CFR 795.10 - Qualified laboratories.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the work to be performed; (2) Has adequate space for material preparation and cleaning and sterilizing... necessary field samples and making hydrologic field measurements and analytical laboratory determinations...

  5. Thermoluminescence studies of γ-irradiated Al2O3:Ce3+ phosphor

    NASA Astrophysics Data System (ADS)

    Reddy, S. Satyanarayana; Nagabhushana, K. R.; Singh, Fouran

    2016-07-01

    Pure and Ce3+ doped Al2O3 phosphors were synthesized by solution combustion method. The synthesized samples were characterized by X-ray diffraction (XRD) and its shows α-phase of Al2O3. Crystallite size was estimated by Williamson-Hall (W-H) method and found to be 49, 59 and 84 nm for pure, 0.1 mol% and 1 mol% Ce3+ doped Al2O3 respectively. Trace elemental analysis of undoped Al2O3 shows impurities viz. Fe, Cr, Mn, Mg, Ti, etc. Photoluminescence (PL) spectra of Al2O3:Ce3+ shows emission at 367 nm and excitation peak at 273 nm, which are corresponding to 5D → 4F and 4F → 5D transitions respectively. PL intensity decreases with concentration up to 0.4 mol%, beyond this mol% PL intensity increases with doping concentration up to 2 mol%. Thermoluminescence (TL) studies of γ-rayed pure and Ce3+ doped Al2O3 have been studied. Two well resolved TL glow peaks at 457.5 K and 622 K were observed in pure Al2O3. Additional glow peak at 566 K was observed in Al2O3:Ce3+. Maximum TL intensity was observed for Al2O3:Ce3+ (0.1 mol%) beyond this TL intensity decreases with increasing Ce3+ concentration. Computerized glow curve deconvolution (CGCD) method was used to resolve the multiple peaks and to calculate TL kinetic parameters. Thermoluminescence emission (TLE) spectra of pure Al2O3 glow peaks (457.5 K and 622 K) shows sharp emission at 694 nm and two small humps at 672 nm and 709 nm. The sharp peak at 696 nm corresponds to Cr3+ impurity of 2Eg → 4A2g transition of R lines and 713 nm hump is undoubtedly belongs to Cr3+ emission of near neighbor pairs. The emission at 672 nm is characteristic of Mn4+ impurity ions of 2E → 4A2 transition. TLE of Al2O3:Ce3+ (0.1 mol%) shows additional broad emission at 412 nm corresponds to F-centers. Linearity is observed in the dose range 20-500 Gy in Al2O3:Ce3+ (1 mol%).

  6. Communication Laboratories: Genesis, Assessment, Challenges.

    ERIC Educational Resources Information Center

    Ellis, Kathleen; Shockley-Zalabak, Pamela; Hackman, Michael Z.

    2000-01-01

    Claims the quality of educational preparation in basic communication skills is insufficient for students to compete in the new millennium. Discusses the communication laboratory as one educational strategy for addressing the issue of communication competency. Describes the rationale for creating a communication laboratory, curricula and…

  7. LABORATORY DESIGN CONSIDERATIONS FOR SAFETY.

    ERIC Educational Resources Information Center

    National Safety Council, Chicago, IL. Campus Safety Association.

    THIS SET OF CONSIDERATIONS HAS BEEN PREPARED TO PROVIDE PERSONS WORKING ON THE DESIGN OF NEW OR REMODELED LABORATORY FACILITIES WITH A SUITABLE REFERENCE GUIDE TO DESIGN SAFETY. THERE IS NO DISTINCTION BETWEEN TYPES OF LABORATORY AND THE EMPHASIS IS ON GIVING GUIDES AND ALTERNATIVES RATHER THAN DETAILED SPECIFICATIONS. AREAS COVERED INCLUDE--(1)…

  8. Photoluminescence and thermoluminescence properties of Eu(2)(+) doped and Eu(2+) ,Dy(3)(+) co-doped Ba2 MgSi2 O7 phosphors.

    PubMed

    Sao, Sanjay Kumar; Brahme, Nameeta; Bisen, D P; Tiwari, Geetanjali

    2016-11-01

    In this work, we report the preparation, characterization, comparison and luminescence mechanisms of Eu(2)(+) -doped and Eu(2)(+) ,Dy(3)(+) -co-doped Ba2 MgSi2 O7 (BMSO) phosphors. Prepared phosphors were synthesized via a high temperature solid-state reaction method. All prepared phosphors appeared white. The phase structure, particle size, and elemental analysis were analyzed using X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX) analysis. The luminescence properties of the phosphors were investigated by thermoluminescence (TL) and photoluminescence (PL). The PL excitation and emission spectra of Ba2 MgSi2 O7 :Eu(2)(+) showed the peak to be around 381 nm and 490 nm respectively. The PL excitation spectrum of Ba2 MgSi2 O7 :Eu(2)(+) Dy(3)(+) showed the peak to be around 341 nm and 388 nm, and the emission spectrum had a broad band around 488 nm. These emissions originated from the 4f(6) 5d(1) to 4f(7) transition of Eu(2)(+) . TL analysis revealed that the maximum TL intensity was found at 5 mol% of Eu(2)(+) doping in Ba2 MgSi2 O7 phosphors after 15 min of ultraviolet (UV) light exposure. TL intensity was increased when Dy(3)(+) ions were co-doped in Ba2 MgSi2 O7 :Eu(2)(+) and maximum TL intensity was observed for 2 mol% of Dy(3)(+) . TL emission spectra of Ba1.95 MgSi2 O7 :0.05Eu(2)(+) and Ba1.93 MgSi2 O7 :0.05Eu(2)(+) ,0.02Dy(3)(+) phosphors were found at 500 nm. TL intensity increased with UV exposure time up to 15 min, then decreased for the higher UV radiation dose for both Eu doping and Eu,Dy co-doping. The trap depths were calculated to be 0.54 eV for Ba1.95 MgSi2 O7 :0.05Eu(2)(+) and 0.54 eV and 0.75 eV for Ba1.93 MgSi2 O7 :0.05Eu(2)(+) ,0.02Dy(3)(+) phosphors. It was observed that co-doping with small amounts of Dy(3)(+) enhanced the thermoluminescence properties of Ba2 MgSi2 O7 phosphor. Copyright © 2016 John Wiley & Sons, Ltd. [Correction added on 5 April 2016, after first online publication

  9. Elimination of redundant thermoluminescent dosemeter monitoring at Oyster Creek nuclear generating station

    SciTech Connect

    Schwartz, P.E.

    1989-01-01

    The Oyster Creek direct radiation monitoring network has long been operating using several time-scale measurements. This network is used to assess the radiation levels during normal plant operations as well as to set the background radiation levels used to determine the radiological impact of a nonroutine release of radioactivity from the plant. Through analysis of the behavior of the monthly and quarterly activity of several types of direct radiation monitoring, the successful elimination of redundant and artificially high measurement techniques has been done in concert with providing the community with most efficient direct radiation monitoring methods. Dose rates from external radiation sources are measured around licensed U.S. Nuclear Regulatory Commission (NRC) facilities using passive detectors known as thermoluminescent dosimeters (TLDs). These detectors provide a quantitative measurement of the radiation levels in the are in which they are placed. The detected radiation could be the result of cosmic or naturally occurring origin in the air and on the ground, prior nuclear weapons testing, and activity from a nuclear facility. This paper describes the TLD network placed around the Oyster Creek nuclear generating station (OCNGS) and the comparisons between TLDs of different manufacturers and of different resident times and the successful elimination of the less accurate monthly TLD for the purpose of cost containment.

  10. The Thermoluminescence Response of Ge-Doped Flat Fibers to Gamma Radiation

    PubMed Central

    Mat Nawi, Siti Nurasiah Binti; Wahib, Nor Fadira Binti; Zulkepely, Nurul Najua Binti; Amin, Yusoff Bin Mohd; Min, Ung Ngie; Bradley, David Andrew; Md Nor, Roslan Bin; Maah, Mohd Jamil

    2015-01-01

    Study has been undertaken of the thermoluminescence (TL) yield of various tailor-made flat cross-section 6 mol% Ge-doped silica fibers, differing only in respect of external dimensions. Key TL dosimetric characteristics have been investigated, including glow curves, dose response, sensitivity, fading and reproducibility. Using a 60Co source, the samples were irradiated to doses within the range 1 to 10 Gy. Prior to irradiation, the flat fibers were sectioned into 6 mm lengths, weighed, and annealed at 400 °C for 1 h. TL readout was by means of a Harshaw Model 3500 TLD reader, with TLD-100 chips (LiF:Mg, Ti) used as a reference dosimeter to allow the relative response of the fibers to be evaluated. The fibers have been found to provide highly linear dose response and excellent reproducibility over the range of doses investigated, demonstrating high potential as TL-mode detectors in radiation medicine applications. Mass for mass, the results show the greatest TL yield to be provided by fibers of the smallest cross-section, analysis indicating this to be due to minimal light loss in transport of the TL through the bulk of the silica medium. PMID:26307987

  11. Evaluation of external dose equivalent with thermoluminescent dosimeters from residents living in radiation-contaminated buildings.

    PubMed

    Lee, J S; Dong, S L; Chang, W P; Chan, C C

    1997-09-01

    As of October 1996 there are more than 90 radiation-contaminated steel supported rebar buildings (containing more than 1000 apartments) dispersed in the northern part of Taiwan. These apartments were contaminated with cobalt-60 at a total activity ranging from 1-140 microSv/yr. In this paper, a method is developed for evaluating external dose equivalent and dose equivalent rates encountered by the residents wearing specially designed thermoluminescent dosimeter (TLD)-embedded chains, belts and badges. Comparisons are also made between the TLD readings and the exposure readings from indoor layout personal dosimetry surveys and room occupancy adjustments to the buildings. The accuracy and sensitivity of the TLDs compared with the ionization chamber readings are judged to be considerable improvements over those of previous studies. From the present study, it is concluded that the reliability of the daily activity records provided by the residents during the entire TLD-wearing period is the most critical but challenging feature of the external dose equivalent measurement.

  12. Kinetic parameters of lithium and aluminium doped quartz from thermoluminescence glow curves.

    PubMed

    Gómez-Ros, J M; Correcher, V; García-Guinea, J; Delgado, A

    2002-01-01

    The thermoluminescence (TL) glow curves of irradiated annealed and non-annealed synthetic beta-quartz (Li0.73Al0.73Si1.27O4) synthesised using the ceramic method have been studied. Annealed samples (1200 degrees C for 12 h) exhibit some changes of shape and intensity in the TL glow curves when compared to non-annealed samples in the range of 0.1-5 Gy. These changes can be attributed mainly to thermal alkali self-diffusion through the lattice interfaces involving modifications in the components of the luminescent traps. In non-annealed samples six groups of components at about 100 degrees C, 130 degrees C, 160 degrees C, 210 degrees C, 330 degrees C and 450 degrees C can be found, whereas annealed samples only display one very intense peak at a lower temperature (deconvoluted into three peaks at 90 degrees C, 105 degrees C and 130 degrees C) and a lower intensity second wide broad emission at approximately 240 degrees C. In this paper, a computerised curve-fitting based on general order kinetics has been used to characterise the glow curve structure resolving trapping parameters for each glow peak: trap depth (E), frequency factor (s) and the order of the kinetics (b). The dose dependence of the individual components of the glow curve has been also studied. These data allow us to select the most stable component for use in dosimetric purposes.

  13. Thermoluminescence detection of Korean traditional foods exposed to Gamma and electron-beam irradiation

    NASA Astrophysics Data System (ADS)

    Kwon, J. H.; Chung, H. W.; Byun, M. W.; Kang, I. J.

    1998-06-01

    Thermoluminescence(TL) analysis was applied to detect irradiated Korean traditional condiments and soup mixes containing salt(NaCl). These food items, which are commercially irradiated in Korea, showed a consistently high correlation(R 2) between the absorbed doses and the corresponding TL responses. It was proved that table salt played a role as an in-built indicator in TL measurements and its concentration in test samples was proposed as a correction factor for varying conditions of TL measurements. Pre-established threshold values were successfully adopted to identify 167 coded samples of Ramen soup mixes, both non-irradiated and irradiated with gamma and electron-beam energy. The TL intensity of irradiated soup mixes decreased with the lapse of time, but was still distinguishable from that of the non-irradiated samples at the fourth month of ambient storage. Expected estimates of absorbed doses, 2.85 and 4.75 kGv were obtained using a quadratic equation with average values of 1.57 and 4.90 kGy, respectively.

  14. Identification of irradiated spices by the use of thermoluminescence method (TL)

    NASA Astrophysics Data System (ADS)

    Sharifzadeh, M.; Sohrabpour, M.

    1993-07-01

    In this paper the results of the investigations of identification of irradiated spices by the use of thermoluminescence method is reported. The materials used were black and red peppers, turmeric, cinnamon, and garlic powder. Gamma Cell 220 was used for irradiating samples at dose values of 2.5, 5, 7.5 and 10 kGy respectively. The TL intensity of the unirradiated spices as well as the fading characteristics of the irradiated samples having received a dose of 10 kGy have been measured. Post-irradiation temperature treatment of the irradiated (10 kGy) and unirradiated samples at 60°C and 100°C for 24 hours have been also performed. The results show that the TL intensities of unirradiated and irradiated samples from different batches of each spice are fairly distributed. A reasonable TL intensity versus dose has been observed in nearly all cases. Based on the observations made it is possible to distinguish irradiated spices after (4-9) months post-irradiation.

  15. Thermoluminescence dating of soils in a semi-arid environment, Yucca Mountain area, Southern Nevada, USA

    SciTech Connect

    Mahan, S.A.; Paces, J.B.; Peterman, Z.E.

    1995-12-31

    Yucca Mountain, Nevada, is currently being investigated as a potential nuclear waste repository. Because radionuclides must be isolated over a ten to several hundred thousand year time span, an assessment of the performance depends in part on accurate reconstruction of the Quaternary geologic and hydrologic history of the mountain. Reliable geochronology in an oxidizing environment dominated by coarse-grained, clastic surficial deposits has become a central issue for several studies including paleoseismic reconstruction, determination of rates of erosion and deposition, and the history of regional water-table fluctuations documented by ground-water discharge deposits. Thermoluminescence (TL) dating of polymineralic silt fractions in a variety of surface deposits has become an important component of the Quaternary dating strategy, along with uranium-series disequilibrium dating of secondary carbonate and opaline silica, and to a lesser extent, radiocarbon dating of carbonate components. Although the complex mineralogy of these materials contributes to greater amounts of scatter in their TL response relative to typical quartzofeldspathic loess and dune deposits, the derived ages are reproducible, consistent with internal stratigraphy, and generally concordant with other available geochronology.

  16. Response of Harshaw neutron thermoluminescence dosemeters in terms of the revised ICRP/ICRU recommendations.

    PubMed

    Veinot, K G; Hertel, N E

    2005-01-01

    To monitor workers for external neutron radiation dose, the Y-12 National Security Complex utilises the thermoluminescence dosemeters (TLDs) manufactured by Harshaw. At Y-12, the majority of external dose to workers is due to low-energy photon and/or beta particles emitted from uranium and its progeny. However, some neutron dose is expected since neutrons are produced from (alpha,n) reactions in various compounds found at the plant, including UF4 and UF6. Neutron sources, such as 252Cf, are also used throughout the complex. The Harshaw neutron dosemeter consists of two gamma-sensitive elements (7Li) and two neutron-sensitive elements enriched in 6Li with various shielding/filter materials placed around each of them. In this work, the energy response of the dosemeter to neutrons has been calculated using the Monte Carlo transport code MCNP Version 4-C and, these results are compared with the measured response of the dosemeter to unmoderated and D2O-moderated 252Cf neutrons. The response of the dosemeter has also been determined in terms of the personal absorbed dose and personal dose equivalent as a function of neutron energy based on the recommendations of the ICRP Publication 60 and ICRU Report 49. The energy response of the dosemeter characteristics can be used to generate spectral conversion coefficients for routine neutron absorbed dose and dose equivalent calculations.

  17. Study of induced thermoluminescence in CVD diamond film by low-energy X-rays.

    PubMed

    Liu, Chi-Chang; Lin, Jao-Perng; Chu, Tieh-Chi

    2003-07-01

    For diamond film the one-hit model that is used to interpret low-energy X-ray thermoluminescence (TL) will require some modifications. After the films were irradiated with a superficial X-ray machine with different peak voltages, a two-compartment model with three parameters, the target size, the microscopic saturation factor and the high-LET saturation factor, was used to more precisely describe the TL response to X-ray with energies down to 10 kV. The microdosimetric distribution was calculated using single-event Monte Carlo code developed by authors together with EEDL cross-section data library. Some mechanistic insight into the physical aspect of radiation interaction with solid detectors can be obtained. The sensitive size in diamond was found to be about 15 nm. The saturation of one group of sublevels combined with the activation of another group of sublevels caused the relative efficiency to have a local minimum near 20 keV. The relative efficiency becomes higher below 10 keV, which is similar to the increasing relative biological effectiveness when the linear energy transfer passing through a biological system increases. The similarity made this material to be a molecular-scale dosimeter in the future.

  18. Thermoluminescence and excess 226Ra decay dating of late Quaternary fluvial sands, East Alligator River, Australia

    NASA Astrophysics Data System (ADS)

    Murray, Andrew; Wohl, Ellen; East, Jon

    1992-01-01

    Thermoluminescence (TL) dating was applied to seven samples of siliceous fluvial sands from the East Alligator River of Northern Australia, giving ages ranging from modern to 6000 yr B.P. Two methods of estimating the equivalent dose (ED), total bleach and regenerative, were applied to the 90- to 125-μm quartz fraction of the samples in order to determine the reliability and internal consistency of the technique. High-resolution γ and α spectroscopy were used to measure radionuclide contents; these measurements revealed an excess 226Ra activity compared with 230Th. This excess decreased with depth, and was used directly to derive mean sedimentation rates, and thus sediment ages. Both this method and one 14C date confirmed the validity of the TL values, which increased systematically with depth and were consistent with site stratigraphy. TL was of limited use in the dating of these late Holocene deposits because of age uncertainties of 500 to 1600 yr, resulting from a significant residual ED. This residual probably resulted from incomplete bleaching during reworking upstream of the sampling site. For Pleistocene deposits, the residual ED will be less significant because of higher total EDs, and TL dates will be correspondingly more accurate.

  19. Study on the response of thermoluminescent dosemeters to synchrotron radiation: experimental method and Monte Carlo calculations.

    PubMed

    Bakshi, A K; Chatterjee, S; Palani Selvam, T; Dhabekar, B S

    2010-07-01

    In the present study, the energy dependence of response of some popular thermoluminescent dosemeters (TLDs) have been investigated such as LiF:Mg,Ti, LiF:Mg,Cu,P and CaSO(4):Dy to synchrotron radiation in the energy range of 10-34 keV. The study utilised experimental, Monte Carlo and analytical methods. The Monte Carlo calculations were based on the EGSnrc and FLUKA codes. The calculated energy response of all the TLDs using the EGSnrc and FLUKA codes shows excellent agreement with each other. The analytically calculated response shows good agreement with the Monte Carlo calculated response in the low-energy region. In the case of CaSO(4):Dy, the Monte Carlo-calculated energy response is smaller by a factor of 3 at all energies in comparison with the experimental response when polytetrafluoroethylene (PTFE) (75 % by wt) is included in the Monte Carlo calculations. When PTFE is ignored in the Monte Carlo calculations, the difference between the calculated and experimental response decreases (both responses are comparable >25 keV). For the LiF-based TLDs, the Monte Carlo-based response shows reasonable agreement with the experimental response.

  20. Comparative identification of irradiated herbs by the methods of electron paramagnetic resonance and thermoluminescence

    NASA Astrophysics Data System (ADS)

    Yordanov, N. D.; Gancheva, V.; Radicheva, M.; Hristova, B.; Guelev, M.; Penchev, O.

    1998-12-01

    Non irradiated and γ-irradiated dry herbs savoury ( Savoury), wild thyme ( Thymus serpollorium) and marjoram ( Origanum) with absorbed dose of 8 kGy have been investigated by the methods of elecrtron paramagnetic resonance (EPR) and thermoluminescence (TL). Non-irradiated herbs exhibit only one weak siglet EPR signal whereas in irradiated samples its intensity increase and in addition two satelite lines are recorded. This triplet EPR spectrum is attributed to cellulose free radical generated by irradiation. It has been found that upon keeping the samples under the normal stock conditions the life-time of the cellulose free radical in the examined samples is ˜60-80 days. Thus the conclusion has been made that the presence of the EPR signal of cellulose free radical is unambiguous indication that the sample under study has been irradiated but its absence can not be considered as the opposite evidence. In the case when EPR signal was absent the method of TL has been used to give the final decision about the previous radiation treatment of the sample.

  1. Rethinking About Chronology Of Chichen Itza: By Thermoluminescence Dating Of Volcanic Glass.

    NASA Astrophysics Data System (ADS)

    Chung, H.; Gonzalez, P.; Ramirez, A.; Schaaf, P.; Lee, I.

    One of the most frequently recurring questions in archaeology concerns the age of the studied objects. To date, determining the chronology of the Puuc and Chichen Slate pottery of Chchen Itza, based on the stylistic change in the pottery, has been problematic. The Thermoluminescence method of dating pottery was applied to samples of Chichen Itza, Yucatan, Mexico, which contain volcanic glass as temper. They were analyzed using the fine grain technique. The radisotopes that contribute to the accumulate annual dose in ceramic samples (40K, 238U, 232Th) were determined by means of Energy Dispersive X-ray Spectroscopy and Neutron Activation Analysis technique, while the artificial irradiation of the samples was carried out using 90Sr source beta radiation. We obtained results indicating the following dates; 875 ± 88; 1055 ± 85; 1063 ± 47, 1154 ± 76; 1110 ± 53, 1132 ± 69, 1221 ± 30, 1532 ± 26. The results demonstrate a chronological order of dates. Most results are in accordance with the established dates of Chichen Itza. However, Puuc and Chichen Slate did not show differences of 200 years as previously proposed, and there is evidence of an earlier period than those two pottery periods. This necessitates a reconsideration of the chronology of Chichen Itza.

  2. Thermoluminescence characterization of Ag-doped Li2 B4 O7 single crystal materials.

    PubMed

    Kuralı, D; Ekdal Karalı, E; Kelemen, A; Holovey, V; Can, N; Karalı, T

    2016-12-13

    In this study, the thermoluminescence (TL) characteristics of Ag-doped and undoped lithium tetraborate (Li2 B4 O7 , LTB) materials, grown using the Czochralski method, were reported. The TL properties of LTB:Ag, such as glow curve structure, dose response, fading and reproducibility, were investigated. The glow curve of the Li2 B4 O7 :Ag single crystal consists of four peaks located at approximately 75, 130, 190 and 275°C; in undoped LTB, the single crystal shows a broad glow curve with peaks at 65, 90, 125, 160 and 190°C using a heating rate of 5°C/s in the 50-350°C temperature region. The high temperature peak of Ag-doped sample at 275°C has a nonlinear dose response within the range from 33 mGy to 9 Gy. There is a linear response in the range of 33-800 mGy; after which, a sublinear region appears up to 9 Gy for Ag-doped LTB single crystal. For undoped single crystal, the dose response is supralinear for low doses and linear for the region between 1 and 9 Gy. The thermal fading ratio of the undoped material is almost 60% for the high temperature peak after 7 days. Ag-doped LTB single crystal exhibits different behaviour over a period of 7 days.

  3. Synthesis, thermoluminescence, defect centers and dosimetric characteristics of LiF:Mg,Cu,B phosphor.

    PubMed

    Preto, Prince David; Balraj, Vidyavathy; Dhabekar, Bhushan S; Watanabe, S; Rao, T K Gundu

    2016-12-01

    The present paper reports the thermoluminescence (TL), dosimetric characteristics and electron spin resonance (ESR) of LiF: Mg, Cu,B (MCB) phosphor synthesized by a solid state method. Its glow curve structure is similar to that of LiF: Mg, Cu,P (MCP) phosphor with the main dosimetric peak at 218°C. MCB is 12 times more sensitive than LiF: Mg, Ti and about 1.9 times less sensitive than MCP phosphor. A noteworthy feature is that the phosphor exhibits a linear dose response up to 100Gy with a minimum detectable dose of 17μGy. The TL emission spectrum was recorded and the post irradiation fading in MCB at ambient temperatures and humidity was negligible for a period of one month. Room temperature ESR spectrum of irradiated phosphor consists of at least two distinct centers. Center I with an isotropic g factor 2.0061 is attributable to an F-center and is the likely recombination center for the main TL peak at 220°C. Center II characterized by a g-factor 2.0090 and an unusual broad line (linewidth ~ 415G) is also identified as an F-center. A third defect center, observable during thermal annealing at high temperature, is assigned to another F-center.

  4. Thermoluminescence properties of gamma irradiated CaO: Sm3+ phosphor

    NASA Astrophysics Data System (ADS)

    Prakash, D.; Nagabhushana, K. R.

    2016-07-01

    Pure and samarium doped calcium oxide (CaO) is synthesized by solution combustion technique. The samples are annealed at 600 °C for two hours. X-ray diffraction (XRD) pattern of the annealed sample show cubic phase with space group Fm3m. The average crystallite size is found to be ∼54 nm. Fourier transform infra red (FTIR) spectrum exhibits bands at 424, 544 cm-1 (Ca-O bond), 875 cm-1 (C-O bond), 1460 cm-1 (C-O stretch) and 3640 cm-1 (O-H stretch). The samples are irradiated with gamma rays in a dose range 100-4000 Gy. Thermoluminescence (TL) glow curves are recorded at a linear heating rate (β) of 5 Ks-1. A prominent TL glow with a peak at 636 K is observed in undoped sample. A new TL glow with peak at ∼458 K is observed in addition to 636 K in samarium doped (1 mol%) CaO. TL glow peak intensity (Imax) at 636 K increases with γ - dose in the study range. TL emissions at 560, 600 and 640 nm are observed in doped samples corresponding to Sm3+ transitions along with pristine emissions. TL glow curves are deconvoluted to obtain kinetic parameters. The mean value of activation energy and the frequency factor of the prominent deconvoluted TL glow peak (626 K) are found to be 1.26 eV and 4.49 × 109 s-1 respectively.

  5. Swift heavy ion induced phase transformation and thermoluminescence properties of zirconium oxide

    NASA Astrophysics Data System (ADS)

    Lokesha, H. S.; Nagabhushana, K. R.; Singh, Fouran

    2016-07-01

    Zirconium oxide (ZrO2) powder is synthesized by combustion technique. XRD pattern of ZrO2 shows monoclinic phase with average crystallite size 35 nm. Pellets of ZrO2 are irradiated with 100 MeV swift Si7+, Ni7+ and 120 MeV swift Ag9+ ions in the fluence range 3 × 1010-3 × 1013 ions cm-2. XRD pattern show the main diffraction peak correspond to monoclinic and tetragonal phase of ZrO2 in 2θ range 27-33°. Structural phase transformation is observed for Ni7+ and Ag9+ ion irradiated samples at a fluence 1 × 1013 ions cm-2 and 3 × 1012 ions cm-2 respectively, since the deposited electronic energy loss exceeds an effective threshold (>12 keV nm-1). Phase transition induced by Ag9+ ion is nearly 2.9 times faster than Ni7+ ion at 1 × 1013 ions cm-2. Ag9+ ion irradiation leads two ion impact processes. Thermoluminescence (TL) glow curves exhibit two glows, a well resolved peak at ∼424 K and unresolved peak at 550 K for all SHI irradiated samples. TL response is decreased with increase of ion fluence. Beyond 3 × 1012 ions cm-2, samples don't exhibit TL due to annihilation of defects.

  6. Thermoluminescence kinetic parameters of different amount La-doped ZnB₂O₄.

    PubMed

    Kucuk, Nil; Gozel, Aziz Halit; Yüksel, Mehmet; Dogan, Tamer; Topaksu, Mustafa

    2015-10-01

    The kinetic parameters of 1%, 2%, 3% and 4% La-doped ZnB2O4 phosphors (i.e. ZnB2O4:0.01La, ZnB2O4:0.02La, ZnB2O4:0.03La and ZnB2O4:0.04La) synthesized by nitric acid method have been calculated. Thermoluminescence (TL) glow curves of ZnB2O4:La phosphors after beta-irradiation showed a very well defined main peak having the maximum temperature at around 200°C and a shoulder peak at around 315°C with a constant heating rate of 5°C/s. The kinetic parameters of ZnB2O4:La phosphors TL glow peaks (i.e. order of kinetics (b), activation energies (Ea) and frequency factors (s)) have been determined and evaluated by Computerized Glow Curve Deconvolution (CGCD), and Peak Shape (PS) methods using the glow curve data. From the results, it can conclude that the values of Ea obtained with these methods for ZnB2O4:La phosphors are consistent with each other, but the s values differ considerably.

  7. The Thermoluminescence Response of Ge-Doped Flat Fibers to Gamma Radiation.

    PubMed

    Nawi, Siti Nurasiah Binti Mat; Wahib, Nor Fadira Binti; Zulkepely, Nurul Najua Binti; Amin, Yusoff Bin Mohd; Min, Ung Ngie; Bradley, David Andrew; Nor, Roslan Bin Md; Maah, Mohd Jamil

    2015-08-20

    Study has been undertaken of the thermoluminescence (TL) yield of various tailor-made flat cross-section 6 mol% Ge-doped silica fibers, differing only in respect of external dimensions. Key TL dosimetric characteristics have been investigated, including glow curves, dose response, sensitivity, fading and reproducibility. Using a (60)Co source, the samples were irradiated to doses within the range 1 to 10 Gy. Prior to irradiation, the flat fibers were sectioned into 6 mm lengths, weighed, and annealed at 400 °C for 1 h. TL readout was by means of a Harshaw Model 3500 TLD reader, with TLD-100 chips (LiF:Mg, Ti) used as a reference dosimeter to allow the relative response of the fibers to be evaluated. The fibers have been found to provide highly linear dose response and excellent reproducibility over the range of doses investigated, demonstrating high potential as TL-mode detectors in radiation medicine applications. Mass for mass, the results show the greatest TL yield to be provided by fibers of the smallest cross-section, analysis indicating this to be due to minimal light loss in transport of the TL through the bulk of the silica medium.

  8. Thermoluminescence in pure LiF crystals: Glow peaks and their connection with color centers

    SciTech Connect

    Baldacchini, G.; Montereali, R. M.; Nichelatti, E.; Kalinov, V. S.; Voitovich, A. P.; Davidson, A. T.; Kozakiewicz, A. G.

    2008-09-15

    Nominally pure LiF crystals were irradiated with the same dose (0.85 10{sup 6} R) of gamma rays at ambient and low temperatures (-60 deg. C) and the resulting thermoluminescence (TL) is reported. Various optical and thermal treatments were applied in order to change the concentration of color centers (CCs). The effect of such treatments on the glow curves is observed. Knowing the coloration from optical transmission and photoluminescence measurements made on the same samples, we attribute many of the glow peaks (GPs) to the annealing of F center aggregates. For the present conditions of irradiation and dose, TL processes begin with decay of F{sub 3}{sup +} centers that display a GP at 164 deg. C. F{sub 3}(R) centers follow and are responsible for GPs at 193 and 228 deg. C. A GP at 263 deg. C is ascribed to F{sub 2} centers. Several peaks at temperatures in the range of 280-380 deg. C are associated with impurity perturbed F centers. A GP at 410 deg. C is associated with a complex of aggregated F and H centers. These attributions are accomplished by means of TL spectra, optical transmission spectra, and annealing procedures, and are critically discussed. The experimental data confirm the general trend of thermal stability of CCs, which decreases by moving from simple F centers to more complex ones, and the existence of exchange dynamics among CCs.

  9. The natural thermoluminescence of meteorites. V - Ordinary chondrites at the Allan Hills ice fields

    NASA Technical Reports Server (NTRS)

    Benoit, Paul H.; Sears, Hazel; Sears, Derek W. G.

    1993-01-01

    Natural thermoluminescence (TL) data have been obtained for 167 ordinary chondrites from the ice fields in the vicinity of the Allan Hills in Victoria Land, Antarctica, in order to investigate their thermal and radiation history, pairing, terrestrial age, and concentration mechanisms. Natural TL values for meteorites from the Main ice field are fairly low, while the Farwestern field shows a spread with many values 30-80 krad, suggestive of less than 150-ka terrestrial ages. There appear to be trends in TL levels within individual ice fields which are suggestive of directions of ice movement at these sites during the period of meteorite concentration. These directions seem to be confirmed by the orientations of elongation preserved in meteorite pairing groups. The proportion of meteorites with very low natural TL levels at each field is comparable to that observed at the Lewis Cliff site and for modern non-Antarctic falls and is also similar to the fraction of small perihelia orbits calculated from fireball and fall observations. Induced TL data for meteorites from the Allan Hills confirm trends which show that a select group of H chondrites from the Antarctic experienced a different extraterrestrial thermal history to that of non-Antarctic H chondrites.

  10. Thermoluminescence and the shock and reheating history of meteorites. III - The shergottites

    NASA Technical Reports Server (NTRS)

    Hasan, F. A.; Haq, M.; Sears, D. W. G.

    1986-01-01

    Thermoluminescence (TL) measurements on Shergotty, ALHA 77005, Zagami, and EETA 79001 (lithology A) have been used to obtain further information on the shock history of these meteorites. The level of TL sensitivity in the shergottites varied by a factor of 10, but was always low, probably reflecting the amount of crystalline material in the maskelynite. There are trends in the TL peak temperature, peak width, and TL sensitivity which are believed to be associated with different proportions of feldspar in high- and low-temperature forms. This interpretation is consistent with the observed changes induced in the TL properties by annealing shergottites at 400-900 C. It is suggested that the observed trends were produced during postshock crystallization at a variety of cooling rates, the increasing order of cooling rate being EETA 79001, Zagami, ALHA 77005, and Shergotty, and that there is high-temperature feldspar present in all the samples. This implies a postshock temperature above 600 C, and a small (less than 10 m) size of the ejecta. Current theories are well able to explain how objects of this size could have been ejected from Mars.

  11. The natural thermoluminescence of meteorites. 7: Ordinary chondrites from the Elephant Moraine region, Antarctica

    NASA Technical Reports Server (NTRS)

    Benoit, P. H.; Roth, J.; Sears, H.; Sears, D. W. G.

    1994-01-01

    We report natural and induced thermoluminescence (TL) measurements for meteorites from the Elephant Moraine region (76 deg 17 min S, 157 deg 20 min E) of Antarctica. We use our data to identify fragmented meteorites (i.e., 'pairings'); our dataset of 107 samples represents at most 73 separate meteorite falls. Pairing groups are generally confined to single icefields, or to adjacent icefields, but a small proportion cross widely separated icefields in the region, suggesting that the fields can be considered as a single unit. Meteorites from this region have high natural TL levels, which indicates that they have small terrestrial surface exposure ages (less than 12,500 years). There do not appear to be significant differences in natural TL levels (and hence surface exposure ages) between individual blue icefields in the region. The proportion of reheated meteorites from the Elephant Moraine region is similar to that of other Antarctic sites and modern falls, consistent with the uniformity of the meteoritic flux in this regard. An unusual subset of H-chondrites, with high induced TL peak temperatures, is absent among the data for meteorites collected in the Elephant Moraine region, which stresses their similarity to modern falls. We suggest that the Elephant Moraine region, which stresses their similarity to modern falls. We suggest that the Elephant Moraine icefields formed through shallow ablation of the ice. Unlike the Allan Hills sites to the south, lateral transport is probably less important relative to the infall of meteorites in concentrating meteorites on these icefields.

  12. Effect of heating rate on the thermoluminescence and thermal properties of natural ulexite.

    PubMed

    Topaksu, M; Correcher, V; Garcia-Guinea, J; Yüksel, M

    2014-10-31

    Boron-rich compounds are of interest in the nuclear industry because they exhibit a high neutron absorption cross section. The manufacture of these materials involves the application of thermal and chemical treatments. This paper focuses on the study of the effect of the heating rate (HR) in two thermal techniques, differential thermal analysis (DTA) and thermoluminescence (TL), performed on natural ulexite from Bigadiç-Balıkesir (Turkey). The TL measurements were performed at six different heating rates in the range of 25-240°Cmin(-1). The UV-blue TL emission of natural ulexite shifted toward higher temperatures with increasing heating rate, whereas the intensity decreased. The kinetic parameters of the ulexite (Ea=0.65(9) eV and s=1.22×10(12)s(-1)) were calculated using the variable heating rate method. DTA measurements performed in the range of 0.5-10°Cmin(-1) displayed similar behavior to that of the TL response, despite the differences in technique and HR values. The DTA results indicated that natural ulexite exhibits two endothermic peaks originating from different processes: (i) a phase transition between the pentahydrated ulexite phase and a triple-hydrated phase and (ii) dehydration, dehydroxylation and alkali and earth-alkali self-diffusion processes in the ulexite lattice. The main endothermic peak shifted from 160°C to 250°C as the heating rate was increased.

  13. EFFECT OF TIME EXPOSURE ON THERMOLUMINESCENCE GLOW CURVE FOR UV-INDUCED ZRO2:MG PHOSPHOR.

    PubMed

    Sadati, S M; Feghhi, S A H; Mohammadi, K

    2016-03-17

    In this research, the effect of magnesium (Mg) impurity on thermoluminescence (TL) response of ZrO2 phosphors is studied experimentally. In the experimental procedure, ZrO2:Mg phosphors in the powder form were synthesised by the sol-gel method. The obtained hydrogel was dried in air and then calcinated in air at 1200°C for 5 h and next was annealed at 250°C for 2 h. Sample characterisations were done by X-ray diffraction and scanning electron microscopy. Obtained materials had monoclinic phase and porous microstructure. Then, known amounts of ZrO2:Mg powder were exposed to ultraviolet lamp from 0.5 to 120 min. The TL peaks were obtained at the same temperature as 75, 137 and 260°C, respectively. Adding Mg to pure zirconia caused to increase TL intensity and shift peaks related to pure zirconia. The TL peaks of the pure zirconia were seen at the 83, 132 and 235°C. Finally, ZrO2:Mg TL experimental results show the linear dose response, high stability and less fading.

  14. Developing an Optimum Protocol for Thermoluminescence Dosimetry with GR-200 Chips using Taguchi Method.

    PubMed

    Sadeghi, Maryam; Faghihi, Reza; Sina, Sedigheh

    2016-11-24

    Thermoluminescence dosimetry (TLD) is a powerful technique with wide applications in personal, environmental and clinical dosimetry. The optimum annealing, storage and reading protocols are very effective in accuracy of TLD response. The purpose of this study is to obtain an optimum protocol for GR-200; LiF: Mg, Cu, P, by optimizing the effective parameters, to increase the reliability of the TLD response using Taguchi method. Taguchi method has been used in this study for optimization of annealing, storage and reading protocols of the TLDs. A number of 108 GR-200 chips were divided into 27 groups, each containing four chips. The TLDs were exposed to three different doses, and stored, annealed and read out by different procedures as suggested by Taguchi Method. By comparing the signal-to-noise ratios the optimum dosimetry procedure was obtained. According to the results, the optimum values for annealing temperature (°C), Annealing Time (s), Annealing to Exposure time (d), Exposure to Readout time (d), Pre-heat Temperature (°C), Pre-heat Time (s), Heating Rate (°C/s), Maximum Temperature of Readout (°C), readout time (s) and Storage Temperature (°C) are 240, 90, 1, 2, 50, 0, 15, 240, 13 and -20, respectively. Using the optimum protocol, an efficient glow curve with low residual signals can be achieved. Using optimum protocol obtained by Taguchi method, the dosimetry can be effectively performed with great accuracy.

  15. Gamma irradiated thermoluminescence response of Ge-doped SiO2 fibre.

    PubMed

    Wahib, Norfadira; Zulkepely, Nurul Najua; Mat Nawi, Siti Nurasiah; Amin, Yusoff Mohd; Ling, Yap Seong; Abdul Sani, Siti Fairus; Maah, Mohd Jamil; Bradley, D A

    2015-11-01

    Over the past decade and more, considerable interest has been shown in the thermoluminescence (TL) properties of silica-based single-mode optical fibres, in particular investigating potential ionising radiation dosimetry applications. Herein, study has been made of TL glow curve, dose response, reproducibility and fading of 6mol% Ge-doped silica, fabricated in-house and produced in the form of cylindrical fibres. Three different pairings of doped-core and silica cladding diameters were produced: (40, 241)µm, (80, 483)µm and (100, 604)µm. The TL results were compared against that of TLD-100, one of the most sensitive commercially available LiF-based TL media. For all three pairings of diameters, closely similar TL glow curve were obtained, formed of a single peaked structure with a maximum TL yield located between the temperatures 250 and 310°C. The TL yield of the fibres were linear over the range of doses investigated, from 1Gy up to 10Gy, their dose response exceeding that of TLD-100, the samples also being found to be reusable, without evidence of degradation.

  16. Thermoluminescence dosimetry features of DY and Cu doped SrF2 nanoparticles under gamma irradiation.

    PubMed

    Zahedifar, M; Sadeghi, E; Kashefi biroon, M; Harooni, S; Almasifard, F

    2015-11-01

    Dy and Cu-doped SrF2 nanoparticles (NPs) were synthesized by using co-precipitation method and their possible application to solid state dosimetry were studied and compared to that of pure SrF2 NPs. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) were used for sample characterization. The highest thermoluminescence (TL) response of SrF2:Dy and SrF2:Cu NPs were found respectively at 0.5 and 0.7mol% of Dy and Cu impurities. Seven overlapping glow peaks at 384, 406, 421, 449, 569, 495, 508K and three component glow peaks at 381, 421 and 467K were identified respectively for SrF2:Dy and SrF2:Cu NPs employing Tm-Tstop and computerized glow curve deconvolution (CGCD) methods. The TL sensitivity of SrF2:Dy is approximately the same as that of LiF:Mg,Ti (TLD-100) cheeps. Linear dose response were observed for the SrF2:Dy and SrF2:Cu NPs up to the absorbed doses of 1kGy and 10kGy correspondingly. Regarding other dosimetry characteristics of the produced NPs such as fading, reproducibility and thermal treatment, Dy and Cu doped SrF2 NPs recommend for high dose TL dosimetry applications.

  17. Thermoluminescence Dynamics During Destructions of Porous Structures Formed by Nitrogen Nanoclusters in Bulk Superfluid Helium

    NASA Astrophysics Data System (ADS)

    Meraki, Adil; Mao, Shun; McColgan, Patrick T.; Boltnev, Roman E.; Lee, David M.; Khmelenko, Vladimir V.

    2016-11-01

    We studied the dynamics of thermoluminescence during destruction of porous structures formed by nanoclusters of nitrogen molecules containing high concentrations of stabilized nitrogen atoms. The porous structures were formed in bulk superfluid helium by injection of the products of discharges in nitrogen-helium gas mixtures through the liquid helium surface. Fast recombination of nitrogen atoms during warming-up led to explosive destruction of the porous structures accompanied by bright flashes. Intense emissions from the α -group of nitrogen atoms, the β -group of oxygen atoms and the Vegard-Kaplan bands of N_2 molecules were observed at the beginning of destruction. At the end of destruction the M- and β -bands of NO molecules as well as bands of O_2 molecules were also observed. Observation of the emissions from NO molecules at the end of destruction was explained by processes of accumulation of NO molecules in the system due to the large van der Waals interaction of NO molecules. For the first time, we observed the emission of the O_2 molecules at the end of destruction of the porous nitrogen structures as a result of the (NO)_2 dimer formation in solid nitrogen and subsequent processes leading to the appearance of excited O_2 molecules.

  18. INVESTIGATION OF THERMOLUMINESCENCE CHARACTERISTICS OF Y2O3:Er3+ NANOPHOSPHORS.

    PubMed

    Kaur, Manmeet; Bisen, D P; Brahme, N; Singh, Prabhjot

    2016-03-05

    Thermoluminescence (TL) characteristics of Y2O3:Er(3+) nanophosphor exposed to UV radiations were investigated. Combustion synthesis method was employed to synthesise the nanophosphors. The confirmation for the pure cubic phase was done by powder X-ray diffraction. The particles formed were found to have 23.19 nm size and it was calculated by the Debye-Scherrer formula for [222] plane and is in close agreement with those obtained using transmission electron microscopy analysis. scanning electron microscopy micrograph reveals porous, irregular shaped particles with large agglomeration of particles whereas Fourier transform infrared spectroscopy studies confirm the presence of organic residua OH and CO in the samples. TL characteristics of UV irradiated Y2O3:Er(3+) for (1-5) mol % were investigated. All the TL glow curves show almost similar glow curves having a single broad peak at 113.26, 113.82 113.72, 113.74 and 113.72°C for 1, 2, 3, 4 and 5 mol %, respectively, of Er(3+) ions. The effects of heating rate were also studied and the trapping parameters, namely activation energy (E), order of kinetics (b) and frequency factor (s) were determined using Chen's peak shape method and computerised glow curve deconvolution technique suggested by Kitis for second-order kinetics. They were also discussed in detail for their possible usage in dosimetry.

  19. Two-dimensional thermoluminescence method for checking LiF crystals homogeneity

    NASA Astrophysics Data System (ADS)

    Marczewska, B.; Bilski, P.; Gieszczyk, W.; Kłosowski, M.

    2017-01-01

    Thermoluminescence (TL), being one of the common luminescence methods, is very sensitive to the presence of any impurities in the material structure and can be used for the detection of impurity distribution in the bulk of the crystal. If in a TL reader a CCD camera is used, a measurement of TL signal would give us an unique two-dimensional (2-D) imaging of TL signal distribution, and thereby the distribution of dopants. The possibility of the application of 2-D TL method for the control of uniformity of the crystal related to dopant distribution in the volume of the bulk crystal was tested on the large area samples of LiF doped and un-doped crystals grown by Czochralski method at the IFJ PAN in Kraków. The special TL reader with a CCD camera was used for analyzing of luminescence emitting during the heating of the irradiated in uniform radiation field slices of crystals cut longitudinal and perpendicular to the growth axis and for analyzing of the shape of TL glow curves for selected crystal areas. Non-uniform distribution of the dopants was demonstrated for doped crystal grown with relatively slow growth rate.

  20. Radioluminescence and thermoluminescence of rare earth element and phosphorus-doped zircon

    SciTech Connect

    Karali, T.; Can, N.; Townsend, P.D.; Rowlands, A.P.; Hanchar, J.M.

    2000-06-01

    The radioluminescence and thermoluminescence spectra of synthetic zircon crystals doped with individual trivalent rare earth element (REE) ions (Pr, Sm, Eu, Gd, Dy, Ho, Er, and Yb) and P are reported in the temperature range 25 to 673 K. Although there is some intrinsic UV/blue emission from the host lattice, the dominant signals are from the rare-earth sites, with signals characteristic of the REE{sup 3+} states. The shapes of the glow curves are different for each dopant, and there are distinct differences between glow peak temperatures for different rare-earth lines of the same element. Within the overall set of signals there are indications of linear trends in which some glow peak temperatures vary as a function of the ionic size of the rare earth ions. The temperature shifts of the peaks are considerable, up to 200{degree}, and much larger than those cited in other rare-earth-doped crystals of LaF{sub 3} and Bi{sub 4}Ge{sub 3}O{sub 12}. The data clearly suggest that the rare-earth ions are active both in the trapping and luminescence steps, and hence the TL occurs within localized defect complexes that include REE{sup 3+} ions.

  1. Effect of oxygen ion irradiation on dielectric, structural, chemical and thermoluminescence properties of natural muscovite mica.

    PubMed

    Kaur, Sukhnandan; Singh, Surinder; Singh, Lakhwant

    2017-03-01

    Thin cleaved samples (~18µm) of natural muscovite mica were irradiated with 80MeV oxygen ion beam at fluence ranging from 1×10(12) to 5×10(13)ion/cm(2). The alterations in dielectric, structural, chemical and thermoluminescence properties of irradiated as well as pristine samples have been investigated. Dielectric constant decreases while other dielectric parameters such as dielectric loss, tanδ, ac conductivity, real and imaginary parts of electric modulus increase with increase of ion fluence. Williamson Hall investigation has been utilized to ascertain crystallite size and micro strain of pristine and irradiated samples. The XRD analysis revealed a significant increase in micro strain and dislocation density with an increase of ion fluence. The variations in dielectric properties upon irradiation are collaborated with structural modifications in the muscovite. No appreciable changes in characteristic bands (FTIR) have been observed after irradiation, indicating that natural muscovite mica is chemically stable. Natural muscovite mica has eminent applications in heavy ions dosimetry due to observation of well defined single peak at 303°C with activation energy of 1.24eV in TL spectrum.

  2. Thermoluminescence characteristics of X-ray induced kyanite mineral and its thermal quenching parameters

    NASA Astrophysics Data System (ADS)

    Kalita, J. M.; Wary, G.

    2014-04-01

    Thermoluminescence (TL) glow curves of X-ray irradiated micro-grain natural kyanite have been recorded under annealed and un-annealed condition at various heating rates (2, 4, 6, 8 and 10 K s-1). TL parameters such as activation energy, order of kinetic and pre-exponential frequency factor have been investigated from the glow peak by a computerized glow curve deconvolution technique. Variation of peak integrals, peak maximum temperatures, FWHM and activation energy with heating rates have been investigated and the glow curves at higher rates have been found to be influenced by presence of thermal quenching. For annealed sample value of thermal quenching activation energy ( W) and pre-exponential factor ( C) are found to be 0.86 ± 0.02 eV and 2.5 × 109 s-1 respectively and for un-annealed sample these values are 1.68 ± 0.03 eV and 3.1 × 1010 s-1 respectively. Experimentally measured value of W and C have been verified by estimating thermal quenching efficiencies η( T) with the help of calculated value of W and C; quenched glow curves have been successfully reconstructed for each heating rate. The dose sensitivity of both types of samples is also reported. Annealed sample shows improved dose response than un-annealed sample.

  3. Thermoluminescence properties of natural zoisite mineral under γ-irradiations and high temperature annealing

    NASA Astrophysics Data System (ADS)

    Ccallata, H. Javier; Filho, L. Tomaz; Watanabe, S.

    2011-04-01

    Natural silicate mineral of zoisite, Ca 2Al 3(SiO 4)(Si 2O 7)O(OH), has been investigated concerning γ-radiation, UV-radiation and high temperature annealing effects on thermoluminescence (TL). X-ray diffraction (XRD) measurement confirmed zoisite structure and X-ray fluorescence (XRF) analysis revealed besides Si, Al and Ca that are the main crystal components, other oxides of Fe, Mg, Cr, Na, K, Sr, Ti, Ba and Mn which are present in more than 0.05 wt%. The TL glow curve of natural sample contains (130-150), (340-370) and (435-475) °C peaks. Their shapes indicated a possibility that they are result of composition of two or more peaks strongly superposed, a fact confirmed by deconvolution method. Once pre-annealed at 600 °C for 1 h, the shape of the glow curves change and the zoisite acquires high sensitivity. Several peaks between 100 and 400 °C appear superposed, and the high temperature peak around 435 °C cannot be seen. The ultraviolet radiation, on the other hand, produces one TL peak around 130 °C and the second one around 200 °C and no more.

  4. An automated research facility for measuring thermoluminescence emission spectra using an optical multichannel analyzer

    NASA Astrophysics Data System (ADS)

    Piters, T. M.; Meulemans, W. H.; Bos, A. J. J.

    1993-01-01

    A facility for research into the mechanism of thermoluminescence (TL) is described. The facility comprises three units: an annealing oven, an irradiator, and a TL-emission spectrometer. Crystals or hot-pressed chips can be moved from and to the mentioned units by an automated sample changer. All units operate automatically and are controlled by a personal computer program. The spectrometer is based on a dispersive grating and an intensified diode array (512 active elements) and covers the 200-800-nm wavelength range. The wavelength resolution of the spectrometer is 6 nm when a 25-μm-wide entrance slit is used and 29 nm when a 1-mm-wide entrance slit is used. The sensitive spectrometer could measure emission spectra of CaSO4:Dy (TLD-200) irradiated at an absorbed dose as low as 3 mGy at a signal-to-noise ratio of 10:1 for LiF:Mg,Ti (TLD-100) this ratio was obtained at 75 mGy. A detailed description is given how measured data can be related to spectra predicted by a model, taking into account all system aberrations. Spectra of LiF:Mg,Ti (TLD-100) irradiated to an absorbed dose of 5 Gy are analyzed according to the Franck-Condon model for light emission. Two emission bands with peak energies of 3.01 and 2.60 eV at 463 K have been found.

  5. The thermoluminescence response of doped SiO2 optical fibres subjected to fast neutrons.

    PubMed

    Hashim, S; Bradley, D A; Saripan, M I; Ramli, A T; Wagiran, H

    2010-01-01

    This paper describes a preliminary study of the thermoluminescence (TL) response of doped SiO(2) optical fibres subjected to (241)AmBe neutron irradiation. The TL materials, which comprise Al- and Ge-doped silica fibres, were exposed in close contact with the (241)AmBe source to obtain fast neutron interactions through use of measurements obtained with and without a Cd filter (the filter being made to entirely enclose the fibres). The neutron irradiations were performed for exposure times of 1-, 2-, 3-, 5- and 7-days in a neutron tank filled with water. In this study, use was also made of the Monte Carlo N-particle (MCNP) code version 5 (V5) to simulate the neutron irradiations experiment. It was found that the commercially available Ge-doped and Al-doped optical fibres show a linear dose response subjected to fast neutrons from (241)AmBe source up to seven days of irradiations. The simulation performed using MCNP5 also exhibits a similar pattern, albeit differing in sensitivity. The TL response of Ge-doped fibre is markedly greater than that of the Al-doped fibre, the total absorption cross section for Ge in both the fast and thermal neutrons region being some ten times greater than that of Al.

  6. Measurements of radiation exposure of dentistry students during their radiological training using thermoluminescent dosimetry.

    PubMed

    Loya, M; Sanín, L H; González, P R; Ávila, O; Duarte, R; Ojeda, S L; Montero-Cabrera, M E

    2016-01-01

    Exposure among dentistry students has not been assessed or regulated in Mexico. This work assessed the average exposure of 35 dentistry students during their training with the aid of LiF:Mg,Cu,P+PTFE thermoluminescent dosimeters. For the students in the roles of dentist and observers, maximum accumulated equivalent dose obtained was 2.59±0.11 and 4.64±0.39 mSv, respectively. Students in the role as patients received a maximum accumulated effective dose of 28.41±0.31 mSv. If compared to occupational dose limits, this latter value is 56% of the recommended value of 50 mSv in any year. It was found that in all cases, values of equivalent dose to the women breasts were equal to the background dose. Results are discussed and compared to previous published work. Suggested recommendations were given to authorities in order to minimize exposure of the students in the role as patients.

  7. Laboratory Building

    SciTech Connect

    Herrera, Joshua M.

    2015-03-01

    This report is an analysis of the means of egress and life safety requirements for the laboratory building. The building is located at Sandia National Laboratories (SNL) in Albuquerque, NM. The report includes a prescriptive-based analysis as well as a performance-based analysis. Following the analysis are appendices which contain maps of the laboratory building used throughout the analysis. The top of all the maps is assumed to be north.

  8. Carbon Characterization Laboratory Report

    SciTech Connect

    David Swank; William Windes; D.C. Haggard; David Rohrbaugh; Karen Moore

    2009-03-01

    The newly completed Idaho National Laboratory (INL) Carbon Characterization Laboratory (CCL) is located in Lab-C20 of the Idaho National Laboratory Research Center. This laboratory was established under the Next Generation Nuclear Plant (NGNP) Project to support graphite research and development activities. The CCL is designed to characterize and test carbon-based materials such as graphite, carbon-carbon composites, and silicon-carbide composite materials. The laboratory is fully prepared to measure material properties for nonirradiated carbon-based materials. Plans to establish the laboratory as a radiological facility within the next year are definitive. This laboratory will be modified to accommodate irradiated materials, after which it can be used to perform material property measurements on both irradiated and nonirradiated carbon-based material. Instruments, fixtures, and methods are in place for preirradiation measurements of bulk density, thermal diffusivity, coefficient of thermal expansion, elastic modulus, Young’s modulus, Shear modulus, Poisson ratio, and electrical resistivity. The measurement protocol consists of functional validation, calibration, and automated data acquisition.

  9. Analytical laboratory quality audits

    SciTech Connect

    Kelley, William D.

    2001-06-11

    Analytical Laboratory Quality Audits are designed to improve laboratory performance. The success of the audit, as for many activities, is based on adequate preparation, precise performance, well documented and insightful reporting, and productive follow-up. Adequate preparation starts with definition of the purpose, scope, and authority for the audit and the primary standards against which the laboratory quality program will be tested. The scope and technical processes involved lead to determining the needed audit team resources. Contact is made with the auditee and a formal audit plan is developed, approved and sent to the auditee laboratory management. Review of the auditee's quality manual, key procedures and historical information during preparation leads to better checklist development and more efficient and effective use of the limited time for data gathering during the audit itself. The audit begins with the opening meeting that sets the stage for the interactions between the audit team and the laboratory staff. Arrangements are worked out for the necessary interviews and examination of processes and records. The information developed during the audit is recorded on the checklists. Laboratory management is kept informed of issues during the audit so there are no surprises at the closing meeting. The audit report documents whether the management control systems are effective. In addition to findings of nonconformance, positive reinforcement of exemplary practices provides balance and fairness. Audit closure begins with receipt and evaluation of proposed corrective actions from the nonconformances identified in the audit report. After corrective actions are accepted, their implementation is verified. Upon closure of the corrective actions, the audit is officially closed.

  10. Making Laboratories Count -- Better Integration of Laboratories in Physics Courses

    NASA Astrophysics Data System (ADS)

    Sizemore, Jim

    2011-10-01

    The quality of K-12 education leaves something to be desired and presents higher education faculty with the challenge of instructing under-prepared students. However, by their own admission, students from many institutions inform us that laboratory sections in science classes, including physics, consist mostly of showing up, going through the motions, and getting grades that boost their overall grade. This work presents laboratories that challenge students to take their laboratory work more seriously including specific rubrics enforcing SOLVE and Bloom's Taxonomy, pre-lab preparation work, and quizzes on pre-lab preparation. Early results are encouraging revealing greater student progress with better integration of laboratory with the rest of a complete physics course.

  11. USGS Scientific Visualization Laboratory

    USGS Publications Warehouse

    ,

    1995-01-01

    The U.S. Geological Survey's (USGS) Scientific Visualization Laboratory at the National Center in Reston, Va., provides a central facility where USGS employees can use state-of-the-art equipment for projects ranging from presentation graphics preparation to complex visual representations of scientific data. Equipment including color printers, black-and-white and color scanners, film recorders, video equipment, and DOS, Apple Macintosh, and UNIX platforms with software are available for both technical and nontechnical users. The laboratory staff provides assistance and demonstrations in the use of the hardware and software products.

  12. Synthesis and thermoluminescence properties of SrAl2O4 (EU) phosphor irradiated with cobalt-60, 6 MV and 16 MV photon beams

    NASA Astrophysics Data System (ADS)

    Pathak, Pushpraj Kumar; Kurchania, Rajnish

    2015-12-01

    Powder samples of SrAl2O4 (Eu) were synthesized by the combustion method using urea as a fuel. The combustion products were calcined at 700 °C for 1 h. X-ray diffraction (XRD) patterns of the prepared sample exhibit sharp diffraction peaks and absence of any amorphous phase. The average crystalline size was found to be ~33.04 nm, calculated by using Debye Scherer's formula. The scanning electron microscope (SEM) images reveal that the crystallites have no uniform shape and the presence of several micro- and nano-particles within the grain. This may be due to the non-uniform distribution of temperature and mass flow in the combustion flame which results in the non-uniform shape of crystallites. The thermogravimetric analysis (TGA) indicates that the prepared sample is thermally stable up to 900 °C. Thermoluminescence (TL) behavior of prepared samples was studied after irradiation with Co-60gamma rays, 6 mega voltage (MV) and 16 MV photon beams at various doses. Glow curve of the prepared SrAl2O4 (Eu:1%) sample was similar in shape irrespective of incident energy and radiation type. The dominant peak in each glow curve appeared around at 312 °C. No shifts in peak positions have been observed. All the glow curves of sample doped with Eu(3%) have relatively higher intensity as compared to the sample doped with Eu(1%). Energy dependence has been observed in the present phosphor. This could be because of increase in the probability of Compton's interaction at this energy range due to transmission of primary as well as scattered radiation and decrease in mass attenuation coefficient with the increase in energy. The trapping parameters namely activation energy (E), order of kinetics (b) and frequency factor (s) have been determined using the glow curve shape (Chen's) method. These phosphors could be utilized for display applications, dating, temperature sensor, low as well as high energy radiation detection and dosimetry especially where tissue equivalency is not much

  13. Chemical Preparation Laboratory for IND Candidate Compounds

    DTIC Science & Technology

    1990-02-08

    CLASSIFICATION lb. RESTRICTIVE MARKINGS Unclassified 2a. SECURITY CLASSIFICATION AUTHORITY 3 . DISTRIBUTION /AVAILABILITY OF REPORT 2b. DECLASSIFICATION... 3 III. Cumulative list of Compounds Delivered to U.S. Army Medical Research and Development (USAMRIID) from January 17, 1989 to...AVS 52) ............................................ 7 2. Selenazole (AVS 253) ............................................... 9 3 . Methyl-l,2,4

  14. Chemical Preparation Laboratory IND Candidate Compounds.

    DTIC Science & Technology

    1986-01-21

    Charcoal (10.0 g) was added and the mixture was stirred at room temperature for an hour, then filtered through a Celite bed. The celite bed was...solvent, the resulting material was dissolved in ethyl acetate (400 mL). Charcoal (5.5 g) was added, and the mixture was stirred at room temperature for 1...hour. The charcoal was filtered through a celite bed and the bed was washed with ethyl acetate (3 x 100 mL). The red-colored filtrate was evaporated

  15. Chemical Preparation Laboratory for IND Candidate Compounds.

    DTIC Science & Technology

    1988-02-05

    29 J. Thiazofurin-nitrile, AVS TFN....................................... 32 K. 4aH-r,lH-trans,l-Hydroxy-8,9- methylenedioxy - l,4,4a...Hydroxy, 2,3,4-triacetoxy-8,9- methylenedioxy -1,2,3,4,4a,10b- hexahydro-6(5H)phenanthridone, AVS 360 OH .......................... 38 d ion M. 4aH-r,lH...trans,2H-cis,3H-trans,4H-trans,l,3,4-Trihydroxy- 2-acetoxy-8,9- methylenedioxy -1,2,3,4,4a,10b-hexahydro- 6(5H)phenanthridone, AVS 360 MA

  16. Chemical Preparation Laboratory for IND Candidate Compounds

    DTIC Science & Technology

    1989-01-31

    AVS 360MA) ..................... 16 6. 1-Hydroxy-8,9- methylenedioxy -1,4,4a,106-tetrahydro-6(5H)phenan- thridone (Intermediate II...carboxylic acid (AVS RCOOH); Lycoricidine triacetate (AVS 360); l-Hydroxy-2-acetoxy-lycoricidine (AVS 360MA); 1- Hydroxy-8,9- methylenedioxy -l,4,4a,106... methylenedioxy -l.2.3.4.4a.l0b-hexahydro- 6(5H)Dhenanthridone (U5): To a mixture of N-methylmorpholine-N-oxide (5.5 g, 47 mmol) in t-butanol (30 mL

  17. Chemical Preparation Laboratory for IND Candidate Compounds.

    DTIC Science & Technology

    1987-01-30

    carboxamide; 4H-r,lH-trans,2H-cis,lObH-trans,l-(2’-tetrahydro- pyranyloxy)-2-hydroxy-8,9- methylenedioxy -1,2,4a,l0b-tetrahydro6(5H)phenan. thridone...4aH-r,lH-trans,2H-cis,lObH-trans-1,2-Dihydroxy-8,9- methylenedioxy - 1,2 ,4a, lOb-tetrahydro-6(5H)phenanthridone. Three compounds remain under...28 K. 4H-r,lH-trans,2H-cis,lObH-trans,l-(2’-Tetrahydro- pyranyloxy)-2-hydroxy-8 9- methylenedioxy -1,2,4a,10b

  18. Chemical Preparation Laboratory for IND Candidate Compounds

    DTIC Science & Technology

    1990-08-10

    Dihydroxy-8 ,9 - methylenedioxy -1 ,2- 4a,l0b-tetrahydro-6(5H)phenanthridone 2.5 g 1986, p.3 1 5 SYN. REFERENCE* I.D. NO. COMPOUND AMOUNT (ANN. CONT. RPT...AVS 360 HP 4H-r,lH-trans,2H-cis,lObH-trans-1- (2’ ,Tetrahydropyranyloxy) -2-hydroxy- 8, 9- methylenedioxy -l, 2,4a, l0b-tetra- hydro-6(5H...Trihydroxy-2 acetoxy-8 ,9- methylenedioxy -I ,3,4, 4a, lOb-hexahydro-6(5H)phenanthridone 1.23 g 1988, p. 16 AVS 360 OH 4aH-r,1H-trans,2H-cis,3H--trans

  19. Comparative analysis of dose rates in bricks determined by neutron activation analysis, alpha counting and X-ray fluorescence analysis for the thermoluminescence fine grain dating method

    NASA Astrophysics Data System (ADS)

    Bártová, H.; Kučera, J.; Musílek, L.; Trojek, T.

    2014-11-01

    In order to evaluate the age from the equivalent dose and to obtain an optimized and efficient procedure for thermoluminescence (TL) dating, it is necessary to obtain the values of both the internal and the external dose rates from dated samples and from their environment. The measurements described and compared in this paper refer to bricks from historic buildings and a fine-grain dating method. The external doses are therefore negligible, if the samples are taken from a sufficient depth in the wall. However, both the alpha dose rate and the beta and gamma dose rates must be taken into account in the internal dose. The internal dose rate to fine-grain samples is caused by the concentrations of natural radionuclides 238U, 235U, 232Th and members of their decay chains, and by 40K concentrations. Various methods can be used for determining trace concentrations of these natural radionuclides and their contributions to the dose rate. The dose rate fraction from 238U and 232Th can be calculated, e.g., from the alpha count rate, or from the concentrations of 238U and 232Th, measured by neutron activation analysis (NAA). The dose rate fraction from 40K can be calculated from the concentration of potassium measured, e.g., by X-ray fluorescence analysis (XRF) or by NAA. Alpha counting and XRF are relatively simple and are accessible for an ordinary laboratory. NAA can be considered as a more accurate method, but it is more demanding regarding time and costs, since it needs a nuclear reactor as a neutron source. A comparison of these methods allows us to decide whether the time- and cost-saving simpler techniques introduce uncertainty that is still acceptable.

  20. Automated Microbial Metabolism Laboratory

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Development of the automated microbial metabolism laboratory (AMML) concept is reported. The focus of effort of AMML was on the advanced labeled release experiment. Labeled substrates, inhibitors, and temperatures were investigated to establish a comparative biochemical profile. Profiles at three time intervals on soil and pure cultures of bacteria isolated from soil were prepared to establish a complete library. The development of a strategy for the return of a soil sample from Mars is also reported.

  1. The thermoluminescence response of doped SiO2 optical fibres subjected to alpha-particle irradiation.

    PubMed

    Ramli, Ahmad Termizi; Bradley, D A; Hashim, Suhairul; Wagiran, Husin

    2009-03-01

    Ion beams are used in radiotherapy to deliver a more precise dose to the target volume while minimizing dose to the surrounding healthy tissue. For optimum dose monitoring in ion-beam therapy, it is essential to be able to measure the delivered dose with a sensitivity, spatial resolution and dynamic range that is sufficient to meet the demands of the various therapy situations. Optical fibres have been demonstrated by this group to show promising thermoluminescence properties with respect to photon, electron and proton irradiation. In particular, and also given the flexibility and small size of optical fibre cores, for example 125.0+/-0.1 microm for the Al- and Ge-doped fibres used in this study, these fibres have the potential to fulfill the above requirements. This study investigates the thermoluminescence dosimetric characteristics of variously doped SiO(2) optical fibres irradiated with alpha particles from (241)Am. Following subtraction of the gamma contribution from the above source, the thermoluminescence characteristics of variously doped SiO(2) optical fibres have been compared with that of TLD-100 rods. The irradiations were performed in a bell jar. Of related potential significance is the effective atomic number, Z(eff) of the fibre, modifying measured dose from that deposited in tissues; in the present work, a scanning electron microscope and associated energy dispersive X-ray spectroscopy facility have been used to provide evaluation of Z(eff). For Ge-doped fibres, the effective atomic numbers value was 11.4, the equivalent value for Al-doped fibres was 12.3. This paper further presents results on dose response and the glow curves obtained. The results obtained indicate there to be good potential for use of variously doped SiO(2) optical fibres in measuring ion-beam doses in radiotherapeutic applications.

  2. Two-point method for kinetic analysis of a thermoluminescence glow peak

    NASA Astrophysics Data System (ADS)

    Ogundare, F. O.; Chithambo, M. L.

    2006-05-01

    We present a method for the estimation of defect (trap) physical parameters from thermoluminescence (TL) glow peaks. In this method, the order of kinetics b is determined using two values of TL intensity each of which corresponds to the same temperature (T-1) on two separate glow peaks of a phosphor. The two glow peaks are obtained from two aliquots of the phosphor irradiated to same dose but read out at different heating rates. The proposed method requires a minimum of only two data points in contrast to standard peak shape (PS) methods that require three points corresponding to three different temperatures on the same glow peak. Once the order of kinetics b is determined, the activation energy E is calculated by taking a second point (T-2) on any one of the two glow peaks. The values of b and E thus obtained are used to evaluate the frequency factor S'' and the number of trapped electrons before the heating begins n(o). The validity of the method was checked using two numerically generated glow peaks. For the two cases, the method reproduced the input values reasonably well. The method was also used to analyse two experimental glow peaks. The results obtained provide a reasonably good fit to the experimental data. The kinetic parameters calculated using the present technique are comparable to those calculated using PS and initial rise methods. Initial guesses can easily be obtained for E and S'' using the present technique when a glow curve is to be deconvoluted with a model consisting of many unknown parameters with E and S'' inclusive.

  3. Chemical and physical studies of type 3 chondrites - VIII: Thermoluminescence and metamorphism in the CO chondrites

    SciTech Connect

    Keck, B.D.; Sears, D.W.G. )

    1987-11-01

    The thermoluminescence properties of nine CO chondrites have been measured. With the exception of Colony and Allan Hills A77307 (ALHA 77307), whose maximum induced TL emission is at approximately 350{degree}C, CO chondrites exhibit two TL peaks, one at 124 {plus minus} 7{degree}C (130{degree}C peak) and one at 252 {plus minus} 7{degree}C (250{degree}C peak). The 130{degree}C peak shows a 100-fold range in TL sensitivity and correlates with various metamorphism-related phenomena, such as silicate heterogeneity, metal composition and McSween's metamorphic subtypes. The peak at 250{degree}C does not show these correlations and, Colony excepted, varies little throughout the class. Mineral separation experiments, and a series of annealing experiments on Isna, suggest that the TL properties for CO chondrites reflect the presence of feldspar in two forms, (1) a form produced during metamorphism, and analogous to the dominant form of feldspar in type 3 ordinary chondrites, and (2) a primary, metamorphism-independent form, perhaps associated with the amoeboid inclusions. If this interpretation is correct, then the CO chondrites have not experienced temperatures above the order/disorder temperature for feldspar (500-600{degree}C) and they cooled more slowly than comparable type 3 ordinary chondrites. Colony and ALHA 77307 have atypical TL properties, including very low TL sensitivity, suggesting that phosphors other than feldspar are important. They have apparently experienced less metamorphism than the others, and may have also been aqueously altered.

  4. Bohunician technology and thermoluminescence dating of the type locality of Brno-Bohunice (Czech Republic).

    PubMed

    Richter, D; Tostevin, G; Skrdla, P

    2008-11-01

    Results of thermoluminescence (TL) dating of 11 heated flint artifacts from the 2002 excavation at Brno-Bohunice, Czech Republic, are presented. The samples are from the eponym locality for the Bohunician, an industrial type considered technologically transitional between Middle and Upper Paleolithic core reduction strategies. The Bohunician is the first early Upper Paleolithic technocomplex in the Middle Danube of Central Europe and, therefore, is implicated in several issues related to the origins of modern humans in Europe. The Bohunician provides an example of how one technological strategy combines crested blade initiation of a core with the surficial (almost Levalloisian) reduction of blanks as blades and points. As the Middle Danube lacks antecedents of the behavioral steps within this technology, several hypotheses of inter-regional cultural transmission, with and without hominin gene flow, could explain the appearance of the Bohunician. The elucidation of the temporal context of Bohunician assemblages is, therefore, a critical step in understanding the behavioral, and potentially biological, succession in this region. Radiocarbon age estimates from charcoal associated with Bohunician sites suggest a wide age range between 33 and 41 ka 14C BP, which is also observed for individual sites. TL dating of heated flint artifacts provides ages on the calendric time scale of an archeological event, the firing. The weighted mean of 48.2+/-1.9 ka BPTL for 11 heated flint samples from Brno-Bohunice provides the first non-radiocarbon data on archeological material from the Bohunician. The TL dating, in conjunction with the archeological and sedimentological analysis, allows the evaluation of the integrity of this new type-collection. The hypothetical possibility of the incorporation of Szeletian artifacts (i.e., leaf points) into the site formation processes can therefore be refuted.

  5. Comparison of thermoluminescence (TL) and cathodoluminescence (ESEM-CL) properties between hydrothermal and metamorphic quartzes.

    PubMed

    Topaksu, M; Correcher, V; Garcia-Guinea, J; Topak, Y; Göksu, H Y

    2012-06-01

    This paper reports on the Thermoluminescence (TL) and Cathodoluminescence (CL) emission of well-characterized hydrothermal milky quartz specimens from Hakkari in Turkey, labeled THQ, and Madrid in Spain, labeled SHQ, and metamorphic quartz from Madrid, in Spain, labeled SMQ. Both hydrothermal and metamorphic quartz samples display similar UV-IR CL spectra consisting of five groups of components centered at 330 nm and 380 nm linked to [AlO(4)]° centers, 420 nm due to intrinsic defects such as oxygen vacancies, lattice defects, and impurities which modify the crystal structure, 480 nm associated with [AlO(4)]° centers of substitutional Al(3+), and a red broad band related to the hydroxyl defects in the quartz lattice as precursors of non-bridging oxygen hole centers (NBOHC) and substitutional point defects. The Turkish quartz specimen exhibits higher CL intensity in the UV region (up to 330 nm) than the Spanish specimens probably linked to the presence of Ca (0.95% in THQ and less than 0.1% in SHQ and SMQ). At wavelengths greater than 330 nm, SMQ (formed at high pressure 6000 bars and temperatures over 500-600°C) shows higher intensity than the hydrothermal (growth at 2000 bars and temperatures 200-300°C) samples associated with the formation process. The natural blue TL glow curves of both THQ and SHQ display a weaker TL intensity than the SMQ, attributable to the Al (0.32%), Ti (0.14%), K (0.01%) and Zr (76 ppm) content. It is shown that mineralogical formation, crystallinity index and the content of the impurities seem to be the main parameters of influence in the shape intensity of the CL and TL glow curve emission.

  6. Low temperature thermoluminescence of annealed LiF:Mg, Cu, P

    NASA Astrophysics Data System (ADS)

    Yang, B.; Gao, H.; Townsend, P. D.

    2006-06-01

    Two main thermoluminescence peaks at 123 and 135 K, plus some weaker features near 65, 95, 242 and 265 K, have been observed in LiF:Mg, Cu, P dosimeter samples that had been annealed at 240 °C. The photon wavelengths in the main peaks span the spectral range from 250 to 470 nm and the maximum intensity is near 310 nm. The origin of these main TL peaks at 123 and 135 K are discussed in terms of a range of defect complexes linked to intrinsic defects. In particular the temperatures match the annealing stages for defect perturbed F-H and VK-e type recombination, respectively. The 65 K feature is considered as the result of electron-hole recombination via relaxed exciton decay. These models suggest reasons for the differences between the various emission bands and the longer wavelength emission linked to high temperature electron decay processes. High temperature annealing modifies the component low temperature TL features with annealing up to ∼300 °C resulting in low temperature TL signal loss, but with partial recovery found for all the low temperature TL peaks when the samples were annealed at higher temperatures up to 390 °C. It is suggested that the intensity loss and the recovery are the summation of numerous effects from a wide range of defect complex variations which exist in these heavily doped materials. The low temperature data offer further insights into the changes which occur in the structures related to optimising the high temperature TL dosimetry.

  7. Gamma-ray thermoluminescence measurements: a record of fallout deposition in Hiroshima?

    PubMed

    Egbert, Stephen D; Kerr, George D

    2012-05-01

    In certain Hiroshima neighborhoods, radiation measurements using thermoluminescence dosimetry (TLD) exceed what can be explained by the initial gamma-ray doses and uncertainties from the Dosimetry System 2002 (DS02). This problem was not previously recognized as being isolated to certain parts of that city. The ratio between TLD measurements and DS02 dose calculations for gamma rays appear to grow larger than unity up to more than three with increasing ground range, but closer examination shows the excess TLD dose (0.1, 0.2, or possibly up to 0.8 Gray) is correlated with certain neighborhoods and could be due to radioactive fallout. At Nagasaki, the TLD measurements do not show this same excess, probably because there were no TLD measurements taken more than 800 m downwind (eastward) from the Nagasaki hypocenter, so that any small excess TLD dose was masked by larger initial gamma-ray doses of 25-80 Gray in the few downwind samples. The DS02 Report had noted many measurements lower than the DS02 calculation for several Nagasaki TLD samples, independent of ground range. This was explained as being the result of previously unaccounted urban shielding which was observed from Nagasaki pre-bomb aerial photos. However, the Hiroshima excess TLD dose issue was not resolved. If the excess TLD doses at Hiroshima are an indication of fallout, it may be possible to use additional TLD studies to make better estimates of the locations and radiation doses to survivors from the fallout after the bombings at both cities.

  8. Thermoluminescent and Monte Carlo dosimetry of a new 170Tm brachytherapy source.

    PubMed

    Nazari, Sona; Sadeghi, Mahdi; Shirvani-Arani, Simindokht; Bahrami-Samani, Ali; Saidi, Pooneh

    2014-03-01

    In this Study characteristics of a new 170Tm brachytherapy seed using thermoluminescent dosimeter and also the Monte Carlo simulations to evaluate between calculated and measured values was determined. Titanium tube contained Tm(NO3)3 powders bombardment at the Tehran Research Reactor (TRR) for a period of 7 days at a flux of 2-3 × 10(13) neutrons/cm2 s. To obtain the radial dose function, g(r), and the anisotropy function, F(r, θ), according to the AAPM TG-43U1 recommendations, 30 cm × 30 cm × 15 cm phantoms of Perspex slabs were used. Brachytherapy dose distributions were simulated with the MCNP5 Monte Carlo (MC) radiation transport code. The MCPLIB04 photon cross-section library was applied using data from ENDF/B-VI. Cell-heating tally, F6 was employed to calculate absorbed dose in two separate runs for both beta and gamma particles. The calculated dose rate constant for the HDR source was found to be 1.113 ± 0.021 cGyU(-1) h(-1). Nominal uncertainty in the measured and calculated radial dose functions, g(r), for the IR-(170)Tm source in Perspex is tabulated is approximately 6% (ranging from 2% to 9%). The anisotropy function, F(r, θ), of the IR-(170)Tm source was measured at radial distances of r = 1.5, 2, 3, 5 cm relative to the seed center, and polar angles θ ranging from 0° to 330° in 30° increments.

  9. Simulations of isothermal processes in the semilocalized transition (SLT) model of thermoluminescence (TL)

    NASA Astrophysics Data System (ADS)

    Pagonis, Vasilis; Kulp, Christopher

    2010-05-01

    Semilocalized transition (SLT) kinetic models for thermoluminescence (TL) contain characteristics of both a localized transition (LT) and of a single trap model. TL glow curves within SLT models typically contain contain two TL peaks; the first peak corresponds to the intra-pair luminescence due to LTs and the second TL peak corresponds to delocalized transitions involving the conduction band (CB). The latter delocalized TL peak has also been found to exhibit non-typical double-peak structure, in which the main TL peak is accompanied by a smaller peak called the displacement peak. This paper describes the simulation of isothermal luminescence signals using a previously published SLT model. It is found that these simulated isothermal signals exhibit several unusual time characteristics. Isothermal signals associated with the LTs follow first order kinetics and are therefore described by single decaying exponentials. However, isothermal signals associated with delocalized transitions show a non-typical complex structure characterized by several time regions with different decay characteristics. For certain values of the parameters in the SLT model the isothermal signals can also exhibit non-monotonic behaviour as a function of time. Another notable result from the simulations is that isothermal currents (which are proportional to the concentration of electrons in the CB) can persist for very long periods of time, even after the apparent termination of the isothermal luminescence signals. It is concluded that isothermal processes described by the SLT model depend strongly on the presence of SLTs, in contrast to previous studies using Monte Carlo simulations, which showed a weak interdependence of these phenomena. The simulations in this paper suggest that isothermal experiments offer a sensitive method for detecting the presence of SLTs in a dosimetric material.

  10. Feasibility of using glass-bead thermoluminescent dosimeters for radiotherapy treatment plan verification

    PubMed Central

    Jordan, Tom J; Distefano, Gail; Bradley, David A; Spyrou, Nicholas M; Nisbet, Andrew; Clark, Catharine H

    2015-01-01

    Objective: To investigate the feasibility of using glass beads as novel thermoluminescent dosemeters (TLDs) for radiotherapy treatment plan verification. Methods: Commercially available glass beads with a size of 1-mm thickness and 2-mm diameter were characterized as TLDs. Five clinical treatment plans including a conventional larynx, a conformal prostate, an intensity-modulated radiotherapy (IMRT) prostate and two stereotactic body radiation therapy (SBRT) lung plans were transferred onto a CT scan of a water-equivalent phantom (Solid Water®, Gammex, Middleton, WI) and the dose distribution recalculated. The number of monitor units was maintained from the clinical plan and delivered accordingly. The doses determined by the glass beads were compared with those measured by a graphite-walled ionization chamber, and the respective expected doses were determined by the treatment-planning system (TPS) calculation. Results: The mean percentage difference between measured dose with the glass beads and TPS was found to be 0.3%, −0.1%, 0.4%, 1.8% and 1.7% for the conventional larynx, conformal prostate, IMRT prostate and each of the SBRT delivery techniques, respectively. The percentage difference between measured dose with the ionization chamber and glass bead was found to be −1.2%, −1.4%, −0.1%, −0.9% and 2.4% for the above-mentioned plans, respectively. The results of measured doses with the glass beads and ionization chamber in comparison with expected doses from the TPS were analysed using a two-sided paired t-test, and there was no significant difference at p < 0.05. Conclusion: It is feasible to use glass-bead TLDs as dosemeters in a range of clinical plan verifications. Advances in knowledge: Commercial glass beads are utilized as low-cost novel TLDs for treatment-plan verification. PMID:26258442

  11. Thermoluminescence and new 14C age estimates for late quaternary loesses in southwestern Nebraska

    USGS Publications Warehouse

    Maat, P.B.; Johnson, W.C.

    1996-01-01

    Loess of late Quaternary age mantles most of Nebraska south of the Platte River Valley. At least five late Quaternary loesses are recognized: from oldest to youngest, one or more undifferentiated pre-lllinoian loesses, the Loveland Loess, the Gilman Canyon Loess, which exhibits a well developed soil and rests unconformably on the Sangamon soil, the Peoria Loess capped by the Brady soil, and the Bignell Loess, which is distributed discontinuously. Previous research shows that the Loveland Loess is Illinoian. the Gilman Canyon Loess and Peoria Loess are Wisconsin, and the Bignell Loess is Holocene. We present here the first thermoluminescence (TL) age estimates and new C ages for these late Quaternary loesses at two key sections in southwestern Nebraska, the Eustis ash pit and the Bignell Hill road cut. TL age estimates from all samples collected from Eustis ash pit and Bignell Hill were internally consistent. TL and C age estimates from these two sections generally agree and support previous age determinations. The TL age estimate on Loveland Loess indicates deposition at 163 ka. TL and radiocarbon age estimates indicate that Oilman Canyon Loess, believed to be deposited during the Farmdale interstade, first began to accumulate at about 40 ka: the lower part of the Gilman Canyon Loess is 36 ka at Eustis and the middle of the unit is 30 ka at Bignell Hill. The lower and upper parts of the Peoria Loess give age estimates of 24 ka and 17 ka, respectively. TL age estimates for deposition of the Bignell Loess are 9 ka near the base, in agreement with radiocarbon age estimates, and 6 ka immediately below the modern soil, substantiating its Holocene age. Comparisons of TL age estimates with ??18O and insolation curves which show loess deposition during interglacial and interstadial as well as glacial periods, indicate that loess deposition on the Great Plains can occur under a variety of climatic conditions.

  12. Thermoluminescence, OSL and defect centers in Tb doped magnesium orthosilicate phosphor.

    PubMed

    Watanabe, S; Rao, T K Gundu; Bhatt, B C; Soni, Anuj; Polymeris, G S; Kulkarni, M S

    2016-09-01

    Mg2SiO4:Tb phosphor exhibits four thermoluminescence (TL) peaks at 124, 244, 300 and 370°C for a heating rate of 2°C/s, 244°C peak being the main dosimetry peak. The irradiated phosphor exhibits CW-OSL response on stimulation with blue (470nm) light. Thermal decay of OSL shows that all the TL traps contribute to CW-OSL signal. Its TL and OSL sensitivities are 0.21 and 0.038, respectively, than that of Al2O3:C (Landauer Inc.). Its CW-OSL response increases linearly up to 30Gy, thereafter increase was supralinear up to the studied dose of 1000Gy. Electron Spin Resonance (ESR) studies were carried out to study the defect centers induced in the phosphor by gamma irradiation and also to identify the centers responsible for the TL process. Room temperature ESR spectrum of irradiated phosphor appears to be a superposition of at least three distinct centers. One of the centers (center I) with an isotropic g-factor 2.0122 is attributable to an intrinsic O(-) radical and this correlates with the main TL peak at 244°C. Center II with an isotropic g-factor 2.0012 is assigned to an F(+)-center (singly ionized oxygen vacancy) and is the likely recombination center for all the TL peaks. Both the centers grow with radiation dose at least up to 1 kGy. Center III with an axial symmetric g-tensor with principal g-values g||=2.0049 and g⊥=2.0029 is identified as an F(+)-center and is not related to the observed TL peaks in the phosphor.

  13. KINETIC SIMULATIONS OF THERMOLUMINESCENCE DOSE RESPONSE: LONG OVERDUE CONFRONTATION WITH THE EFFECTS OF IONISATION DENSITY.

    PubMed

    Horowitz, Y S; Eliyahu, I; Oster, L

    2016-12-01

    The reader will time-travel through almost seven decades of kinetic models and mathematical simulations of thermoluminescence (TL) characteristics based on the band-gap theory of the solid state. From post-World-War II, ideas concerning electron trapping mechanisms to the highly idealised one trap-one recombination (OTOR) model first elaborated in 1956 but still in 'high gear' today. The review caresses but purposely avoids in-depth discussion of the endless stream of papers discussing the intricacies of glow peak shapes arising from first-order, second-order, mixed-order and general-order kinetics predominantly based on non-interacting systems, and then on to the more physically realistic scenarios that have attempted to analyse complex systems involving ever greater numbers of interacting trapping centres, luminescent centres and non-luminescent centres. The review emphasises the difficulty the band-gap models have in the simulation of dose response linear/supralinear behaviour and especially the dependence of the supralinearity on ionisation density. The significance of the non-observation of filling-rate supralinearity in the absorption stage is emphasised since it removes from consideration the possibility of TL supralinearity arising from irradiation stage supralinearity. The importance of the simultaneous action of both localised and delocalised transitions has gradually penetrated the mindset of the community of kinetic researchers, but most simulations have concentrated on the shape of glow peaks and the extraction of the glow peak parameters, E (the thermal activation energy) and s (the attempt-to-escape frequency). The simulation of linear/supralinear dose response and its dependence on ionisation density have been largely avoided until recently due to the fundamental schism between the effects of ionisation density and some basic assumptions of the band-gap model. The review finishes with an in-depth presentation and discussion of the most recent

  14. The Natural Thermoluminescence of Meteorites. Part 5; Ordinary Chondrites at the Allan Hills Ice Fields

    NASA Technical Reports Server (NTRS)

    Benoit, Paul H.; Sears, Hazel; Sears, Derek W. G.

    1993-01-01

    Natural thermoluminescence (TL) data have been obtained for 167 ordinary chondrites from the ice fields in the vicinity of the Allan Hills in Victoria Land, Antarctica, in order to investigate their thermal and radiation history, pairing, terrestrial age, and concentration mechanisms. Using fairly conservative criteria (including natural and induced TL, find location, and petrographic data), the 167 meteorite fragments are thought to represent a maximum of 129 separate meteorites. Natural TL values for meteorites from the Main ice field are fairly low (typically 5-30 krad, indicative of terrestrial ages of approx. 400 ka), while the Far western field shows a spread with many values 30-80 krad, suggestive of less then 150-ka terrestrial ages. There appear to be trends in TL levels within individual ice fields which are suggestive of directions of ice movement at these sites during the period of meteorite concentration. These directions seem to be confirmed by the orientations of elongation preserved in meteorite pairing groups. The proportion of meteorites with very low natural TL levels (less then 5 krad) at each field is comparable to that observed at the Lewis Cliff site and for modern non-Antarctic falls and is also similar to the fraction of small perihelia (less then 0.85 AU) orbits calculated from fireball and fall observations. Induced TL data for meteorites from the Allan Hills confirm trends observed for meteorites collected during the 1977/1978 and 1978/1979 field seasons which show that a select group of H chondrites from the Antarctic experienced a different extraterrestrial thermal history to that of non-Antarctic H chondrites.

  15. Effect of Annealing on the Thermoluminescence Properties of ZnO Nanophosphor

    NASA Astrophysics Data System (ADS)

    Kalita, J. M.; Wary, G.

    2017-02-01

    We report the effect of annealing on the thermoluminescence (TL) properties of zinc oxide (ZnO) nanophosphor. The sample was synthesised by a wet chemical process. The characterisation report shows that the size of the grains is within 123.0 nm-160.5 nm. TL measured at 2 K/s from a fresh un-annealed sample irradiated to 60 mGy shows a composite glow curve containing three peaks at 353.2 K, 429.1 K, and 455.3 K. On the other hand, samples annealed at 473 K and 573 K followed by irradiation to 60 mGy do not give TL. However, annealing at 673 K and 773 K followed by irradiation to the same dose produces a glow curve comprising two overlapping peaks at 352.3 K and 370.6 K. In the TL emission spectrum of un-annealed sample, two emission peaks were found in green ( 523 nm) and orange ( 620 nm) regions whereas in annealed samples, only a peak was found in the orange region ( 618 nm). Kinetic analysis shows that the activation energy corresponding to TL peaks at 353.2 K, 429.1 K, and 455.3 K of the un-annealed sample are 0.64 eV, 0.80 eV, and 1.20 eV whereas that of the peaks at 352.3 K and 370.6 K of 673 K and 773 K annealed samples are 0.64 eV and 0.70 eV, respectively. All peaks of un-annealed and annealed samples, except the one at 429.1 K of the un-annealed sample, follow first-order kinetics whereas the peak at 429.1 K follows second-order kinetics. Considering the kinetic and spectral features, an energy band model for ZnO nanophosphor has been proposed.

  16. Intrinsic dosimetry. Properties and mechanisms of thermoluminescence in commercial borosilicate glass

    SciTech Connect

    Clark, Richard A.

    2012-10-01

    Intrinsic dosimetry is the method of measuring total absorbed dose received by the walls of a container holding radioactive material. By considering the total absorbed dose received by a container in tandem with the physical characteristics of the radioactive material housed within that container, this method has the potential to provide enhanced pathway information regarding the history of the container and its radioactive contents. The latest in a series of experiments designed to validate and demonstrate this newly developed tool are reported. Thermoluminescence (TL) dosimetry was used to measure dose effects on raw stock borosilicate container glass up to 70 days after gamma ray, x-ray, beta particle or ultraviolet irradiations at doses from 0.15 to 20 Gy. The TL glow curve when irradiated with 60Co was separated into five peaks: two relatively unstable peaks centered near 120 and 165°C, and three relatively stable peaks centered near 225, 285, and 360°C. Depending on the borosilicate glass source, the minimum measurable dose using this technique is 0.15-0.5 Gy, which is roughly equivalent to a 24 hr irradiation at 1 cm from a 50-165 ng source of 60Co. Differences in TL glow curve shape and intensity were observed for the glasses from different geographical origins. These differences can be explained by changes in the intensities of the five peaks. Electron paramagnetic resonance (EPR) and multivariate statistical methods were used to relate the TL intensity and peaks to electron/hole traps and compositional variations.

  17. Estimation of band gap of muscovite mineral using thermoluminescence (TL) analysis

    NASA Astrophysics Data System (ADS)

    Kalita, J. M.; Wary, G.

    2016-03-01

    In this article thermoluminescence (TL) mechanism in muscovite mineral has been reported in detail. The trap spectroscopy of the mineral has been studied from the TL glow curve of X-ray irradiated sample. A stable TL peak has been observed at around 347 K in the glow curve, however after annealing the sample above 573 K an additional peak is observed at around 408 K. In the TL emission spectra an emission peak has been observed at around 447 nm at TL peak maximum temperatures. The glow curves are analyzed by Tm-Tstop analysis, peak shape method and fractional glow technique. Analyses showed that there is a trap center and a radiative recombination center at depth around 0.71 and 2.78 eV from the conduction band. These two localized centers do not affected by annealing up to 773 K. However, annealing at 573 K (or above) a new electron trap center was found to generate at depth around 1.23 eV. This significant result has been confirmed with the help of phototransfer phenomena observed under UV irradiation. Due to UV irradiation on the excited sample, the transfer of trapped charges from the deeper trap level (1.23 eV) to the shallow level (0.71 eV) has been observed. Based on the analysis a schematic band diagram of muscovite crystal has been proposed. With the help of the band model, radiative as well as non-radiative recombination mechanisms have been discussed. The band gap of the material has been estimated to be around 5.09 eV and verified.

  18. Modeling the response of thermoluminescence detectors exposed to low- and high-LET radiation fields.

    PubMed

    Olko, Pawel; Bilski, Pawel; Budzanowski, Maciej; Waligórski, Michael Patrick Russell; Reitz, Guenther

    2002-12-01

    Lithium fluoride thermoluminescence (TL) detectors, with different Li composition (Li-6 and Li-7) and various activators (LiF:Mg,Ti, LiF:Mg,Cu,P), are widely used for dosimetry in space. The primary radiation field in space is composed of fast electrons, protons and heavy charged particles (HCP). By its interaction with the structures of the spacecraft, this field may be modified inside the crew cabin. Therefore, calibration of TL detectors against a dose of gamma-rays is not sufficient for relating the TL readout to absorbed dose or to quantities relevant in radiation protection, without suitable correction. We introduce and calculate the detection efficiency, eta, relative to gamma-ray dose, of lithium fluoride detectors after proton and heavy charged particle (HCP) irradiation. We calculate eta for MCP-N (LiF:Mg,Cu,P) and for MTS-N (LiF:Mg,Ti) using microdosimetric models. The microdosimetric distributions used in these models (for HCP of charges between Z=1 to Z=8 and in the energy range between 0.3 MeV/amu and 20 MeV/amu) are calculated using an analytical model, based on the results of Monte Carlo simulated charged particle tracks using the MOCA-14 code. The ratio etaMCP-N/etaMTS-N for protons of stopping power (in water) below 10 keV/microm lies in the range between 0.65 and 1.0 and for HCP with Z>1--between 0.3 and 0.6. The stopping power of the particle is found not to be a unique parameter to scale the response of TL detectors. The combination of response of LiF:Mg,Cu,P and LiF:Mg,Cu,P detectors can be more suitable for a dose correction in space radiation fields.

  19. Thermoluminescent sensitivity of single clad neodymium doped SiO2 optical fibres measured with 6 MeV photons

    NASA Astrophysics Data System (ADS)

    Saeed, M. A.; Hossain, I.; Hida, N.; Wagiran, H.

    2013-10-01

    This study investigates the thermoluminescent sensitivity of neodymium doped SiO2 optical fibre with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MeV photon irradiations. The TL responses of the neodymium doped silica fibres are compared with available TLD-100 dosimeter in order to determine the suitability as a TL material. We found that the TLD-100 and neodymium doped silica fibre have a significant linear signal to dose relationship. Neodymium doped fibres sensitivity is approximately 11% of TLD-100.

  20. Preliminary U-series disequilibrium and thermoluminescence ages of surficial deposits and paleosols associated with Quaternary fault, Eastern Yucca Mountain

    SciTech Connect

    Paces, J.B.; Menges, C.M.; Bush, C.A.; Futa, K.; Millard, H.T.; Maat, P.B.; Whitney, J.W.; Widmann, B.; Wesling, J.R.

    1994-12-31

    Geochronological control is an essential component of paleoseismic evaluation of faults in the Yucca Mountain region. New U-series disequilibrium and thermoluminescence age estimates for pedogenic deposits that bracket surface-rupture events are presented from four sites exposing the Paintbrush Canyon, Bow Ridge and Stagecoach Road faults. Ages show an internal consistency with stratigraphic relationships as well as an overall concordancy between the two independent geochronometers. Age estimates are therefore interpreted to date depositional events or episodes of pedogenic carbonate mobility that can be used to establish a paleoseismic fault chronology. Ultimately, this type of chronological information will be used to evaluate seismic hazards at Yucca Mountain.

  1. Thermoluminescence characteristics of Nd-doped SiO2 optical fibers irradiated with the (60)Co gamma rays.

    PubMed

    Refaei, Azadeh; Wagiran, Husin; Saeed, M A; Hosssain, I

    2014-12-01

    Thermoluminescence (TL) properties (radiation sensitivity, dose response, signal fading) of Nd-doped SiO2 optical fibers irradiated with 1.25MeV photons to 1-50Gy were studied. The peak of the glow curve is around 190°C regardless of the dose. The dose response is linear up to 50Gy. The radiation sensitivity is 219nCmg(-1)Gy(-1). The fiber can be a potential candidate for photon radiotherapy dosimetry due to its high radiation sensitivity, linear dose response in a wide range, slow fading, and high spatial resolution due to the small size of the fiber.

  2. Thermoluminescence responses of the Yb- and Yb-Tb-doped SiO2 optical fibers to 6-MV photons.

    PubMed

    Sahini, M H; Hossain, I; Wagiran, H; Saeed, M A; Ali, H

    2014-09-01

    Characteristics of the thermoluminescence (TL) responses of Yb- and Yb-Tb-doped optical fibers irradiated with 6MV photons are reported. The concentration of Yb in the Yb-doped optical fiber was 0.26mol%; the concentrations of Yb and Tb in the Yb-Tb-doped optical fiber were 0.62 and 0.2mol%, respectively. The TL dose responses are linear in the dose range 0.5-4Gy. The radiation sensitivity of the Yb-Tb material is almost two orders of magnitude higher than the sensitivity of the material doped with Yb alone.

  3. Thermoluminescence studies of Nd doped Bi4Ge3O12 crystals irradiated by UV and beta sources.

    PubMed

    Karabulut, Y; Canimoglu, A; Ekdal, E; Ayvacikli, M; Can, N; Karali, T

    2016-07-01

    Thermoluminescence (TL) glow curves of pure and rare earth doped bismuth germanate (BGO) were investigated under UV and beta radiation. The glow curves of pure BGO crystal present different patterns for both kinds of radiation. The TL glow curves of BGO crystals doped with Nd ions are similar to that of pure BGO under UV radiation. The kinetic parameters, kinetic order (b), activation energy (E) and frequency factor (s) of the TL glow curves of pure BGO crystal have been determined by peak shape method. Activation energies of 3 peaks obtained by PS were found to be 1.81, 1.15 and 1.78, respectively.

  4. Application of radioisotope XRF and thermoluminescence (TL) dating in investigation of pottery from Tell AL-Kasra archaeological site, Syria.

    PubMed

    Abboud, R; Issa, H; Abed-Allah, Y D; Bakraji, E H

    2015-11-01

    Statistical analysis based on chemical composition, using radioisotope X-ray fluorescence, have been applied on 39 ancient pottery fragments coming from the excavation at Tell Al-Kasra archaeological site, Syria. Three groups were defined by applying Cluster and Factor analysis statistical methods. Thermoluminescence (TL) dating was investigated on three sherds taken from the bathroom (hammam) on the site. Multiple aliquot additive dose (MAAD) was used to estimate the paleodose value, and the gamma spectrometry was used to estimate the dose rate. The average age was found to be 715±36 year.

  5. Laboratory accreditation.

    PubMed

    Bradway, D E; Siegelman, F L

    1994-09-01

    An investigation of alleged data fraud at a pesticide analytical laboratory led EPA to take a closer look at the Good Laboratory Practice (GLP) inspection program. There was special focus on changes which might be made in the program to enhance the chances of detecting fraud in regulated studies. To this end, the Assistant Administrator of the Office of Prevention, Pesticides and Toxic Substances (OPPTS) requested EPA's Office of Inspector General (OIG) to examine the GLP program. Several reports were issued by the OIG, including the recommendation that a laboratory accreditation program be adopted. EPA has been examining ways to implement the OIG's recommendations, including (1) laboratory accreditation consisting of three components: document submission and assessment, site visit and assessment, and proficiency assessment; and (2) mandatory registration of all facilities participating in GLP-regulated studies, based on document submission and assessment. These two alternatives are compared, and the advantages and disadvantages of each are discussed.

  6. Effect of co-doping of sodium on the thermoluminescence dosimetry properties of copper-doped zinc lithium borate glass system.

    PubMed

    Saidu, A; Wagiran, H; Saeed, M A; Alajerami, Y S M; Kadir, A B A

    2016-12-01

    The effect of sodium as a co-dopant on the thermoluminescence (TL) properties of copper-doped zinc lithium borate (ZLB: Cu) subjected to Co-60 gamma radiation is reported in this study. TL intensity is enhanced with the introduction of sodium in ZLB: Cu. The obtained glow curve is simple with a single peak. The annealing procedure and the best heating rate for the proposed thermoluminescent dosimeter (TLD) are established, and the phosphor is reusable. The TL response within the dose range of 0.5-1000Gy is investigated. The results show that the thermal fading behaviour is improved significantly.

  7. Roles of laboratories and laboratory systems in effective tuberculosis programmes.

    PubMed

    Ridderhof, John C; van Deun, Armand; Kam, Kai Man; Narayanan, P R; Aziz, Mohamed Abdul

    2007-05-01

    Laboratories and laboratory networks are a fundamental component of tuberculosis (TB) control, providing testing for diagnosis, surveillance and treatment monitoring at every level of the health-care system. New initiatives and resources to strengthen laboratory capacity and implement rapid and new diagnostic tests for TB will require recognition that laboratories are systems that require quality standards, appropriate human resources, and attention to safety in addition to supplies and equipment. To prepare the laboratory networks for new diagnostics and expanded capacity, we need to focus efforts on strengthening quality management systems (QMS) through additional resources for external quality assessment programmes for microscopy, culture, drug susceptibility testing (DST) and molecular diagnostics. QMS should also promote development of accreditation programmes to ensure adherence to standards to improve both the quality and credibility of the laboratory system within TB programmes. Corresponding attention must be given to addressing human resources at every level of the laboratory, with special consideration being given to new programmes for laboratory management and leadership skills. Strengthening laboratory networks will also involve setting up partnerships between TB programmes and those seeking to control other diseases in order to pool resources and to promote advocacy for quality standards, to develop strategies to integrate laboratories functions and to extend control programme activities to the private sector. Improving the laboratory system will assure that increased resources, in the form of supplies, equipment and facilities, will be invested in networks that are capable of providing effective testing to meet the goals of the Global Plan to Stop TB.

  8. The Special Child: Student Laboratory Manual.

    ERIC Educational Resources Information Center

    Texas Tech Univ., Lubbock. Home Economics Curriculum Center.

    This laboratory manual was designed for use by students in postsecondary courses that prepare them to be child caregivers or directors. The workbook is especially useful for students in lecture-laboratory courses on mainstreaming children with special needs into regular child care settings. This manual, designed as a laboratory experience guide…

  9. Determination of trans vitamin K1 in infant and medical nutritional products using AOAC Method 999.15 with modified preparation and extraction procedures and C30 bonded phase chromatography: single-laboratory validation.

    PubMed

    Schimpf, Karen J; Thompson, Linda B; Schmitz, Daniel J

    2010-01-01

    Modifications were made to AOAC Official Method 999.15 to extend its applicability to specialty infant formulas containing hydrolyzed proteins and free amino acids, and to medical and adult nutritional products. Minor changes to the sample preparation procedure and chromatographic separation improved vitamin K1 recoveries and reduced chromatographic interferences in these types of matrixes. Currently AOAC Method 999.15 is applicable only to the determination of total vitamin K1 (phylloquione) in infant formula and milk (fluid, ready-to-feed, and powdered) containing > 1 microg vitamin K1/100 g solids. AOAC Method 999.15 recoveries of vitamin K1 were improved by altering sample sizes, extraction solvents and amounts, and the reagent addition order and amount of water or aqueous solutions added. The chromatographic separation of vitamin K1 in medical nutritional products containing canola and marine oils was improved, and trans vitamin K1 was separated from the biologically inactive cis isomer in all products with a C30 3 microm column and a 100% methanol mobile phase. With these modifications to the extraction procedure and chromatographic separation, AOAC Method 999.15 demonstrated acceptable precision and accuracy for the quantitation of trans vitamin K1 in specialty infant formulas containing hydrolyzed proteins and free amino acids, and medical and adult nutritional products. A single-laboratory validation of these minor modifications was completed. Fourteen different product matrixes were analyzed during validation. The intermediate precision averaged 4.15% RSD (range 2.52-5.81% RSD), and recovery data averaged 100.1% (range 92.2-109%).

  10. Gamma ray induced thermoluminescence properties of Eu{sup 3+} doped SnO{sub 2} phosphor

    SciTech Connect

    Chowdhury, M.; Sharma, S.K.; Lochab, S.P.

    2015-10-15

    Highlights: • TL properties of SnO{sub 2}:Eu{sup 3+} were reported upon γ-ray irradiation. • Effect of doping, irradiation dose and heating rate on TL properties were studied in detail. • The kinetic parameters associated with TL were calculated for first time in SnO{sub 2}:Eu{sup 3+}. • Existence of second-order kinetics indicates the occurrence of retrapping phenomena. • Retrapping of electrons at deep traps occurred due to thermal energy stimulation. - Abstract: This paper reports the thermoluminescence properties of Eu{sup 3+} doped SnO{sub 2} phosphors synthesized by combustion method. The thermoluminescence (TL) studies were carried out after irradiating the sample by γ-rays in the dose range 100 Gy to 1 KGy. The glow curves of γ-irradiated phosphors were resolved into two peaks, one centred at 116 °C and other at 300 °C. Intensity of the glow peak increases linearly in the studied dose range of γ-rays. Kinetic parameters such as order of kinetics, trap depth and frequency factor associated with the glow peak were calculated by various glow curve methods.

  11. Herbicidal effects of harmaline from Peganum harmala on photosynthesis of Chlorella pyrenoidosa: probed by chlorophyll fluorescence and thermoluminescence.

    PubMed

    Deng, Chunnuan; Shao, Hua; Pan, Xiangliang; Wang, Shuzhi; Zhang, Daoyong

    2014-10-01

    The herbicidal effects of harmaline extracted from Peganum harmala seed on cell growth and photosynthesis of green algae Chlorella pyrenoidosa were investigated using chlorophyll a fluorescence and thermoluminescence techniques. Exposure to harmaline inhibited cell growth, pigments contents and oxygen evolution of C. pyrenoidosa. Oxygen evolution was more sensitive to harmaline toxicity than cell growth or the whole photosystem II (PSII) activity, maybe it was the first target site of harmaline. The JIP-test parameters showed that harmaline inhibited the donor side of PSII. Harmaline decreased photochemical efficiency and electron transport flow of PSII but increased the energy dissipation. The charge recombination was also affected by harmaline. Amplitude of the fast phase decreased and the slow phase increased at the highest level of harmaline. Electron transfer from QA(-) to QB was inhibited and backward electron transport flow from QA(-) to oxygen evolution complex was enhanced at 10 μg mL(-1) harmaline. Exposure to 10 μg mL(-1) harmaline caused appearance of C band in thermoluminescence. Exposure to 5 μg mL(-1) harmaline inhibited the formation of proton gradient. The highest concentration of harmaline treatment inhibited S3QB(-) charge recombination but promoted formation of QA(-)YD(+) charge pairs. P. harmala harmaline may be a promising herbicide because of its inhibition of cell growth, pigments synthesis, oxygen evolution and PSII activities.

  12. On the use of LiF:Mg,Ti thermoluminescence dosemeters in space--a critical review.

    PubMed

    Horowitz, Y S; Satinger, D; Fuks, E; Oster, L; Podpalov, L

    2003-01-01

    The use of LiF:Mg,Ti thermoluminescence dosemeters (TLDs) in space radiation fields is reviewed. It is demonstrated in the context of modified track structure theory and microdosimetric track structure theory that there is no unique correlation between the relative thermoluminescence (TL) efficiency of heavy charged particles, neutrons of all energies and linear energy transfer (LET). Many experimental measurements dating back more than two decades also demonstrate the multivalued, non-universal, relationship between relative TL efficiency and LET. It is further demonstrated that the relative intensities of the dosimetric peaks and especially the high-temperature structure are dependent on a large number of variables, some controllable, some not. It is concluded that TL techniques employing the concept of LET (e.g. measurement of total dose, the high-temperature ratio (HTR) methods and other combinations of the relative TL efficiency of the various peaks used to estimate average Q or simulate Q-LET relationships) should be regarded as lacking a sound theoretical basis, highly prone to error and, as well, lack of reproducibility/universality due to the absence of a standardised experimental protocol essential to reliable experimental methodology.

  13. Use of the Oak Ridge National Laboratory tungsten-188/rhenium-188 generator for preparation of the rhenium-188 HDD/lipiodol complex for trans-arterial liver cancer therapy

    SciTech Connect

    Jeong, J M; Knapp Jr, Russ F

    2008-01-01

    This work describes the installation, use, and quality control (QC) of the alumina-based tungsten-188 ({sup 188}W)/rhenium-188 ({sup 188}Re) generators provided by the Oak Ridge National Laboratory (ORNL). In addition, methods used for concentration of the {sup 188}Re-perrhenate bolus and preparation of {sup 188}Re-labeled HDD (4-hexadecyl-2,2,9,9-tetramethyl-4,7-diaza-1,10-decanethiol) for trans-arterial administration for therapy of nonresectable liver cancer also are described. The {sup 188}W/{sup 188}Re generator has a long useful shelf-life of several months and is a convenient on-site {sup 188}Re production system. {sup 188}Re has excellent therapeutic and imaging properties (T{sub 1/2} 16.9 hours; E{sub {beta}max} 2.12 MeV; 155-keV gamma ray, 15%) and is cost effectively obtained on demand by saline elution of the generator. The clinical efficacy of a variety of {sup 188}Re-labeled agents has been demonstrated for several therapeutic applications. Because of the favorable physical properties of {sup 188}Re, several {sup 188}Re-labeled agents are being developed and evaluated for the treatment of nonresectable/refractory liver cancer. {sup 188}Re-labeled HDD has been the most widely studied of these agents for this application and has been introduced into clinical trials at a number of institutions. The trans-arterial administration of {sup 188}Re-labeled agents for treatment of inoperable liver cancer requires use of high-level (1-2 Ci) {sup 188}W/{sup 188}Re generators. The handling of such high levels of {sup 188}Re imposes radiological precautions normally not encountered in a radiopharmacy and adequate care and ALARA (i.e., 'As Low As Reasonably Achievable') principles must be followed. The ORNL generator provides consistently high {sup 188}Re yields (>75%) and low {sup 188}W parent breakthrough (<10{sup -3}%) over an extended shelf-life of several months. However, the high elution volumes (20-40 mL for 1-2 Ci generators) can require concentration of the

  14. Use of the Oak Ridge National Laboratory tungsten-188/rhenium-188 generator for preparation of the rhenium-188 HDD/lipiodol complex for trans-arterial liver cancer therapy.

    PubMed

    Jeong, Jae Min; Knapp, F F Russ

    2008-03-01

    This work describes the installation, use, and quality control (QC) of the alumina-based tungsten-188 ((188)W)/rhenium-188 ((188)Re) generators provided by the Oak Ridge National Laboratory (ORNL). In addition, methods used for concentration of the (188)Re-perrhenate bolus and preparation of (188)Re-labeled HDD (4-hexadecyl-2,2,9,9-tetramethyl-4,7-diaza-1,10-decanethiol) for trans-arterial administration for therapy of nonresectable liver cancer also are described. The (188)W/(188)Re generator has a long useful shelf-life of several months and is a convenient on-site (188)Re production system. (188)Re has excellent therapeutic and imaging properties (T(1/2) 16.9 hours; E(betamax) 2.12 MeV; 155-keV gamma ray, 15%) and is cost effectively obtained on demand by saline elution of the generator. The clinical efficacy of a variety of (188)Re-labeled agents has been demonstrated for several therapeutic applications. Because of the favorable physical properties of (188)Re, several (188)Re-labeled agents are being developed and evaluated for the treatment of nonresectable/refractory liver cancer. (188)Re-labeled HDD has been the most widely studied of these agents for this application and has been introduced into clinical trials at a number of institutions. The trans-arterial administration of (188)Re-labeled agents for treatment of inoperable liver cancer requires use of high-level (1-2 Ci) (188)W/(188)Re generators. The handling of such high levels of (188)Re imposes radiological precautions normally not encountered in a radiopharmacy and adequate care and ALARA (ie, "As Low As Reasonably Achievable") principles must be followed. The ORNL generator provides consistently high (188)Re yields (>75%) and low (188)W parent breakthrough (<10(-3)%) over an extended shelf-life of several months. However, the high elution volumes (20-40 mL for 1-2 Ci generators) can require concentration of the (188)Re bolus by postelution passage through silver cation chloride trapping columns

  15. Low-temperature luminescence and thermoluminescence from BeO:Zn single crystals

    NASA Astrophysics Data System (ADS)

    Ogorodnikov, I. N.; Petrenko, M. D.; Ivanov, V. Yu.

    2016-12-01

    Low-temperature luminescence and thermoluminescence (TL) of BeO:Zn single crystals have been studied in the temperature range of 6-380 K and energy ranges of 1.2-6.5 eV (emission spectra) and 3.7-20 eV (luminescence excitation and reflection spectra). The introduction of zinc impurity ions (0.05 at. %) into BeO host lattice leads to the creation of both the trapped electron and hole centers: Zn+ and Zn2+ O-. These two new centers are responsible for two TL glow peaks at 307 and 145 K with activation energies of 0.96 and 0.40 eV, and two emission bands at 6.0 and 1.9-2.6 eV. The first emission band is attributed to radiative annihilation of the Zn-impurity bound excitons, and the second one is associated with the intracenter electronic transitions in the defect complex comprising zinc impurity ion. The 6.0 eV luminescence center can be excited at 9.6 eV, the low-energy tail of the BeO host absorption, but below the first excitonic maximum (10.45 eV). The 1.9-2.6 eV luminescence center can be excited at the BeO optical transparency band. Both emission bands in BeO:Zn appear in the X-ray induced luminescence spectra at T = 6 K. This indicates that not only these luminescence centers are excited during band-to-band transitions, but they participate in recombination processes as well. The low-temperature (T0 = 6 K) TL study of BeO:Zn single crystals was made for the first time. Analysis of the low-temperature TL glow curves allowed us not only to experimentally determine the energy characteristics of the Zn impurity states in BeO:Zn, but reveal an extremely strong influence of the isovalent zinc impurity on fluctuation rearrangement of BeO host lattice. Note, the fluctuation rearrangement of BeO host lattice, which occurs in the temperature range of self-trapped exciton transformation (80-180 K), was previously known only for undoped BeO and BeO crystals with heterovalent impurities [I. N. Ogorodnikov and A. V. Kruzhalov, Proc. SPIE 2967 (1997) 42].

  16. Thermoluminescence characteristics of Ge-doped optical fibers with different dimensions for radiation dosimetry.

    PubMed

    Begum, Mahfuza; Rahman, A K M Mizanur; Abdul-Rashid, H A; Yusoff, Z; Begum, Mahbuba; Mat-Sharif, K A; Amin, Y M; Bradley, D A

    2015-06-01

    Important thermoluminescence (TL) properties of five (5) different core sizes Ge-doped optical fibers have been studied to develop new TL material with better response. These are drawn from same preform applying different speed and tension during drawing phase to produce Ge-doped optical fibers with five (5) different core sizes. The results of the investigations are also compared with most commonly used standard TLD-100 chips (LiF:Mg,Ti) and commercial multimode Ge-doped optical fiber (Yangtze Optical Fiber, China). Scanning Electron Microscope (SEM) and EDX analysis of the fibers are also performed to map Ge distribution across the deposited region. Standard Gamma radiation source in Secondary Standard Dosimetry Lab (SSDL) was used for irradiation covering dose range from 1Gy to 10Gy. The essential dosimetric parameters that have been studied are TL linearity, reproducibility and fading. Prior to irradiation all samples ∼0.5cm length are annealed at temperature of 400°C for 1h period to standardize their sensitivities and background. Standard TLD-100 chips are also annealed for 1h at 400°C and subsequently 2h at 100°C to yield the highest sensitivity. TL responses of these fibers show linearity over a wide gamma radiation dose that is an important property for radiation dosimetry. Among all fibers used in this study, 100μm core diameter fiber provides highest response that is 2.6 times than that of smallest core (20μm core) optical fiber. These fiber-samples demonstrate better response than commercial multi-mode optical fiber and also provide low degree of fading about 20% over a period of fifteen days for gamma radiation. Effective atomic number (Zeff) is found in the range (13.25-13.69) which is higher than soft tissue (7.5) however within the range of human-bone (11.6-13.8). All the fibers can also be re-used several times as a detector after annealing. TL properties of the Ge-doped optical fibers indicate promising applications in ionizing radiation

  17. Electron spin resonance and thermoluminescence studies in CaSO4: Dy,Ag phosphor

    NASA Astrophysics Data System (ADS)

    Dhabekar, Bhushan; Menon, Sanjeev; Kumar, Rajesh; Gundu Rao, T. K.; Bhatt, B. C.; Lakshmanan, A. R.

    2005-09-01

    The defect centres formed in the thermoluminescence (TL) phosphor CaSO4 : Dy,Ag are studied using the technique of electron spin resonance (ESR). The Ag co-doped phosphor exhibits three glow peaks around 130°C, 220°C and 375°C, in contrast to the two glow peaks observed in the CaSO4 : Dy phosphor at 130°C and 220°C, at gamma ray dose of 1 Gy when the TL measurements were carried out in the spectral region 300-650 nm. ESR studies show that the additional peak at 375°C correlates with a Ag2+ centre formed owing to γ-irradiation and observable below -170°C. The Ag2+ centre is characterized by an axial g-tensor with principal values g|| = 2.38 and gbottom = 2.41. ESR studies further indicate that the precursor to a centre observable at low temperature (-170°C) appears to act as the recombination centre for the TL peak at 375°C; this radical is characterized by the g-values g|| = 2.0023 and gbottom = 2.0038 and is assigned to the SO_{3}^{-} radical. It is observed that there is more incorporation of Ag in the CaSO4 : Dy system as compared with that in the pure CaSO4 system. The variation of Ag2 + ESR intensity with Ag concentration as well as with dose in the range 0.3-120 kGy is studied. The Ag2 + ESR signal and TL saturate at 2 × 104 Gy, but the intensity of the SO_{3}^{-} radical continues to increase up to the studied dose of 1.2 × 105 Gy. The intensity of the SO_{3}^{-} radical decreases with Ag concentration in CaSO4 : Dy,Ag, in agreement with the TL model proposed in this work.

  18. Laboratory diagnosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the first major goals of the microbiology laboratory is to isolate or detect clinically significant microorganisms from an affected site and, if more than one type of microorganism is present, to isolate them in approximately the same ratio as occurs in vivo. Whether an isolate is “clinically...

  19. Intercomparisons to evaluate the suitability of gaschromatographic, electron- spin-resonance spectrometric and thermoluminescence methods to detect irradiated foods in routine control

    NASA Astrophysics Data System (ADS)

    Schreiber, G. A.; Helle, N.; Schulzki, G.; Spiegelberg, A.; Linke, B.; Wagner, U.; Bögl, K. W.

    1993-07-01

    The results of four different intercomparisons to detect irradiated fish and chicken meat containing bones, chicken-, pork- and beef meat without bones, spices, herbes as well as spice- and herb mixtures, various fruit and vegetables as well as pistacchio nuts using gaschromatographic methods, electron-spin resonance spectroscopy or thermoluminescence analyses are reported.

  20. 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.

  1. Characterization of radiation environments at selected Pacific Northwest Laboratory facilities

    SciTech Connect

    Oxley, C.L.

    1992-10-01

    This report is based on a study conducted by Pacific Northwest Laboratory (PNL) from December 15, 1990 to December 15, 1991, to characterize the radiation environments at selected locations within PNL facilities. Thermoluminescent dosimeters were placed at 72 locations to measure non-productive radiation exposure to identify areas in which continuous occupation by a staff member would expose the staff member to radiation exceeding the 100 mrem/yr limit. The areas measured were found to be below the 0.05 mR/hr limit with the exception of three locations. At these three locations above the limit, radiation exposure was reduced by changing office locations and by additional shielding around radiation sources. Evaluations are recommended to determine the causes of elevated exposure rate readings.

  2. Lunar laboratory

    SciTech Connect

    Keaton, P.W.; Duke, M.B.

    1986-01-01

    An international research laboratory can be established on the Moon in the early years of the 21st Century. It can be built using the transportation system now envisioned by NASA, which includes a space station for Earth orbital logistics and orbital transfer vehicles for Earth-Moon transportation. A scientific laboratory on the Moon would permit extended surface and subsurface geological exploration; long-duration experiments defining the lunar environment and its modification by surface activity; new classes of observations in astronomy; space plasma and fundamental physics experiments; and lunar resource development. The discovery of a lunar source for propellants may reduce the cost of constructing large permanent facilities in space and enhance other space programs such as Mars exploration. 29 refs.

  3. Laboratory accreditation

    SciTech Connect

    Pettit, R.B.

    1998-08-01

    Accreditation can offer many benefits to a testing or calibration laboratory, including increased marketability of services, reduced number of outside assessments, and improved quality of services. Compared to ISO 9000 registration, the accreditation process includes a review of the entire quality system, but in addition a review of testing or calibration procedures by a technical expert and participation in proficiency testing in the areas of accreditation. Within the DOE, several facilities have recently become accredited in the area of calibration, including Sandia National Laboratories, Oak Ridge, AlliedSignal FM and T; Lockheed Martin Idaho Technologies Co., and Pacific Northwest National Lab. At the national level, a new non-profit organization was recently formed called the National Cooperation for Laboratory Accreditation (NACLA). The goal of NACLA is to develop procedures, following national and international requirements, for the recognition of competent accreditation bodies in the US. NACLA is a voluntary partnership between the public and private sectors with the goal of a test or calibration performed once and accepted world wide. The NACLA accreditation body recognition process is based on the requirements of ISO Guide 25 and Guide 58. A membership drive will begin some time this fall to solicit organizational members and an election of a permanent NACLA Board of Directors will follow later this year or early 1999.

  4. Space Radiation Effects Laboratory

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The SREL User's Handbook is designed to provide information needed by those who plan experiments involving the accelerators at this laboratory. Thus the Handbook will contain information on the properties of the machines, the beam parameters, the facilities and services provided for experimenters, etc. This information will be brought up to date as new equipment is added and modifications accomplished. This Handbook is influenced by the many excellent models prepared at other accelerator laboratories. In particular, the CERN Synchrocyclotron User's Handbook (November 1967) is closely followed in some sections, since the SREL Synchrocyclotron is a duplicate of the CERN machine. We wish to thank Dr. E. G. Michaelis for permission to draw so heavily on his work, particularly in Section II of this Handbook. We hope that the Handbook will prove useful, and will welcome suggestions and criticism.

  5. Flexible scope for ISO 15189 accreditation: a guidance prepared by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group Accreditation and ISO/CEN standards (WG-A/ISO).

    PubMed

    Thelen, Marc H M; Vanstapel, Florent J L A; Kroupis, Christos; Vukasovic, Ines; Boursier, Guilaime; Barrett, Edward; Bernabeu Andreu, Francisco; Brguljan, Pika Meško; Brugnoni, Duilio; Lohmander, Maria; Sprongl, Ludek; Vodnik, Tatjana; Ghita, Irina; Vaubourdolle, Michel; Huisman, Willem

    2015-07-01

    The recent revision of ISO15189 has further strengthened its position as the standard for accreditation for medical laboratories. Both for laboratories and their customers it is important that the scope of such accreditation is clear. Therefore the European co-operation for accreditation (EA) demands that the national bodies responsible for accreditation describe the scope of every laboratory accreditation in a way that leaves no room for doubt about the range of competence of the particular laboratories. According to EA recommendations scopes may be fixed, mentioning every single test that is part of the accreditation, or flexible, mentioning all combinations of medical field, examination type and materials for which the laboratory is competent. Up to now national accreditation bodies perpetuate use of fixed scopes, partly by inertia, partly out of fear that a too flexible scope may lead to over-valuation of the competence of laboratories, most countries only use fixed scopes. The EA however promotes use of flexible scopes, since this allows for more readily innovation, which contributes to quality in laboratory medicine. In this position paper, the Working Group Accreditation and ISO/CEN Standards belonging to the Quality and Regulation Committee of the EFLM recommends using an approach that has led to successful introduction of the flexible scope for ISO15189 accreditation as intended in EA-4/17 in The Netherlands. The approach is risk-based, discipline and competence-based, and focuses on defining a uniform terminology transferable across the borders of scientific disciplines, laboratories and countries.

  6. Laboratory accreditation and inspection.

    PubMed

    Rauch, Carol A; Nichols, James H

    2007-12-01

    Clinical laboratories perform diagnostic testing in a highly regulated environment in which federal, state, and private accreditation agencies monitor the quality of testing processes. These agencies vary in the focus and stringency of their requirements, and differences exist among states. Continued accreditation requires regular inspection to assure quality of test results for physicians, insurers, and, ultimately, the patients being tested. Preparation for inspection requires understanding of the unique accreditation requirements for each institution, establishment of quality assurance and quality improvement oversight, and communication of each staff member's role in delivering quality test results for patient care.

  7. [Laboratory accreditation and proficiency testing].

    PubMed

    Kuwa, Katsuhiko

    2003-05-01

    ISO/TC 212 covering clinical laboratory testing and in vitro diagnostic test systems will issue the international standard for medical laboratory quality and competence requirements, ISO 15189. This standard is based on the ISO/IEC 17025, general requirements for competence of testing and calibration laboratories and ISO 9001, quality management systems-requirements. Clinical laboratory services are essential to patient care and therefore should be available to meet the needs of all patients and clinical personnel responsible for human health care. If a laboratory seeks accreditation, it should select an accreditation body that operates according to this international standard and in a manner which takes into account the particular requirements of clinical laboratories. Proficiency testing should be available to evaluate the calibration laboratories and reference measurement laboratories in clinical medicine. Reference measurement procedures should be of precise and the analytical principle of measurement applied should ensure reliability. We should be prepared to establish a quality management system and proficiency testing in clinical laboratories.

  8. Prostatic thermoluminescent dosimeter analysis in a patient treated with 18 MV X rays through a prosthetic hip

    SciTech Connect

    Hazuka, M.B.; Stroud, D.N.; Adams, J.; Ibbott, G.S.; Kinzie, J.J. )

    1993-01-15

    External beam radiation therapy with high energy photon beams through hip protheses has been shown to cause dose inhomogeneities for target volumes in the pelvis. In this work, measurements of dose using thermoluminescent dosimetry were compared with dose calculations from a computerized treatment planning system in a patient with prostatic carcinoma and a cobalt-chromium-molybdenum hip prosthesis. A 39% decrement in dose at isocenter was demonstrated for an 18 MV photon beam passing through the prosthesis. A discrepancy of only 3.1% was shown between measured and calculated dose when the tissue-maximum ratio (TMR) method of heterogeneity correction was used. However, it is recognized that several sources of error are possible when heterogeneity corrections are performed for high density prostheses and these are discussed below. The results of this work stress the importance of accurate data for use with the ratio of TMR's' algorithm in order that accurate treatment planning can be performed.

  9. The Australian radiation protection and nuclear safety agency megavoltage photon thermoluminescence dosimetry postal audit service 2007-2010.

    PubMed

    Oliver, C P; Butler, D J; Webb, D V

    2012-03-01

    The Australian radiation protection and nuclear safety agency (ARPANSA) has continuously provided a level 1 mailed thermoluminescence dosimetry audit service for megavoltage photons since 2007. The purpose of the audit is to provide an independent verification of the reference dose output of a radiotherapy linear accelerator in a clinical environment. Photon beam quality measurements can also be made as part of the audit in addition to the output measurements. The results of all audits performed between 2007 and 2010 are presented. The average of all reference beam output measurements calculated as a clinically stated dose divided by an ARPANSA measured dose is 0.9993. The results of all beam quality measurements calculated as a clinically stated quality divided by an ARPANSA measured quality is 1.0087. Since 2011 the provision of all auditing services has been transferred from the Ionizing Radiation Standards section to the Australian Clinical Dosimetry Service (ACDS) which is currently housed within ARPANSA.

  10. Thermoluminescence response of Ge-doped SiO2 fibres to electrons, X- and γ-radiation

    NASA Astrophysics Data System (ADS)

    Entezam, A.; Khandaker, M. U.; Amin, Y. M.; Ung, N. M.; Maah, J.; Bradley, D. A.

    2016-04-01

    For doses from 10 cGy to 80 Gy, we investigate the thermoluminescence (TL) response of tailor-made Ge-doped SiO2 fibres for accelerated electrons (6, 12 and 20 MeV), megavoltage X-rays (6, 10 MV) and 1.25 MeV γ-rays, delivered by a linear accelerator (LINAC) and a Co-60 irradiator respectively. Fibres of various dimensions were fabricated, obtained with doping concentrations from 6% to 10% Ge. The fibres are observed to provide a linear response with radiation dose, an overall reproducibility of 1-5%, and inappreciable dependence on energy, field-size and angular variation. For fibres exposed to 6 MV X-rays, the response increases with core size, the 6% Ge-doped fibres providing the greatest TL yield. The fibres exhibit uniformity of response and provide the basis of a promising TL system for radiotherapy applications, offering high spatial resolution and sensitivity.

  11. Analysis of Potassium in Bricks--Determining the Dose Rate from {sup 40}K for Thermoluminescence Dating

    SciTech Connect

    Musilek, Ladislav; Polach, Tomas; Trojek, Tomas

    2008-08-07

    Thermoluminescence (TL) dating is based on accumulating the natural radiation dose in the material of a dated artefact (brick, pottery, etc.), and comparing the dose accumulated during the lifetime of the object with the dose rate within the sample collected for TL measurement. Determining the dose rate from natural radionuclides in materials is one of the most important and most difficult parts of the technique. The most important radionuclides present are usually nuclides of the uranium and thorium decay series and {sup 40}K. An analysis of the total potassium concentration enables us to determine the {sup 40}K content effectively, and from this it is possible to calculate the dose rate originating from this radiation source. X-ray fluorescence (XRF) analysis can be used to determine the potassium concentration in bricks rapidly and efficiently. The procedure for analysing potassium, examples of results of dose rate calculation and possible sources of error are described here.

  12. Thermoluminescent properties of Ni and Co doped synthetic, high pressure, high temperature diamonds: application to ionising radiation dosimetry.

    PubMed

    Benabdesselam, M; Iacconi, P; Gheeraert, E; Kanda, H; Lapraz, D; Briand, D

    2002-01-01

    An investigation of the thermoluminescence (TL) properties of high pressure, high temperature (HPHT) synthetic diamond crystals grown under diluted nickel or cobalt as solvent catalysts is reported. After a study of TL properties of 6 different samples, it is shown that a crystal grown with Ni+2%Ti and annealed at 2100 K presents an intense glow peak at around 490 K. This peak is characterised by a broad emission band centred at 530 nm (2.34 eV). This crystal presents a significant, reproducible and linear TL response relative to the absorbed dose up to an X ray air kerma of 10 Gy. All these features make this material suitable for ionising radiation dosimetry. A similar study is made on another crystal grown from pure Co, and a comparative review of the results does show that for dosimetry work, Ni-containing diamonds are more appropriate than those grown from Co catalyst.

  13. Thermoluminescence dosimetry of gamma rays using ceramic samples from Hiroshima and Nagasaki: a comparison with DS86 estimates.

    PubMed

    Nagatomo, T; Ichikawa, Y; Hoshi, M

    1991-03-01

    This study reports gamma-ray doses measured using thermoluminescence (TL) dosimetry of atomic-bomb-exposed ceramic samples from Hiroshima and Nagasaki. Advances in the dosimetry of TL-sensitive minerals in the field of TL dating of archaeological and geological materials made it possible to measure a radiation dose of 10(-2) Gy. Ceramic samples such as tiles and bricks were collected from locations between 523 and 2,453 m from the hypocenter in Hiroshima and from between 731 and 1,565 m in Nagasaki. The gamma-ray dose estimates derived from these samples are compared with estimates from DS86. A significant discrepancy was noted between the doses measured for samples from Hiroshima and DS86 values. One possible cause of this discrepancy might be a secondary gamma-ray dose related to the neutron dose.

  14. A Unified Introductory Chemistry Laboratory

    ERIC Educational Resources Information Center

    Splittgerber, A. G.; And Others

    1971-01-01

    Laboratory procedures are explained for taking benzoic acid and using it or one of its derivatives throughout an introductory lab course. Synthesis, purification, weight determination, identification of an acid, equilibrium constant, salt preparation, salt analysis, and salt solubility measurements are involved in the semester's experience. (DS)

  15. Energetics of Photosystem II charge recombination in Acaryochloris marina studied by thermoluminescence and flash-induced chlorophyll fluorescence measurements.

    PubMed

    Cser, Krisztián; Deák, Zsuzsanna; Telfer, Alison; Barber, James; Vass, Imre

    2008-01-01

    We studied the charge recombination characteristics of Photosystem II (PSII) redox components in whole cells of the chlorophyll (Chl) d-dominated cyanobacterium, Acaryochloris marina, by flash-induced chlorophyll fluorescence and thermoluminescence measurements. Flash-induced chlorophyll fluorescence decay was retarded in the mus and ms time ranges and accelerated in the s time range in Acaryochloris marina relative to that in the Chl a-containing cyanobacterium, Synechocystis PCC 6803. In the presence of 3-(3,4-dichlorophenyl)-1, 1-dimethylurea, which blocks the Q(B) site, the relaxation of fluorescence decay arising from S(2)Q(A)(-) recombination was somewhat faster in Acaryochloris marina than in Synechocystis PCC 6803. Thermoluminescence intensity of the so called B band, arising from the recombination of the S(2)Q(B)(-) charge separated state, was enhanced significantly (2.5 fold) on the basis of equal amounts of PSII in Acaryochloris marina as compared with Synechocystis 6803. Our data show that the energetics of charge recombination is modified in Acaryochloris marina leading to a approximately 15 meV decrease of the free energy gap between the Q(A) and Q(B) acceptors. In addition, the total free energy gap between the ground state and the excited state of the reaction center chlorophyll is at least approximately 25-30 meV smaller in Acaryochloris marina, suggesting that the primary donor species cannot consist entirely of Chl a in Acaryochloris marina, and there is a contribution from Chl d as well.

  16. Near-field dosimetry of {sup 125}I sources for interstitial brachytherapy implants measured using thermoluminescent sheets

    SciTech Connect

    Iwata, Kazuro; Yue, Ning J.; Nath, Ravinder

    2004-12-01

    The dosimetric characteristics were measured for two types of {sup 125}I low-energy photon-emitting sources by using a wide and highly sensitive thermoluminescent (TL) sheet film, which was developed for two-dimensional dose distribution measurements. The TL film is made of Teflon homogeneously mixed with small powders of thermoluminescence (BaSO{sub 4}:Eu doped). Various dosimetric parameters (i.e., radial dose function, 2D and 1D anisotropy functions) of model 6711 and 6702 {sup 125}I sources were obtained at various distances from the source surfaces to 15 mm. These parameters obtained with TL sheet were compared with the data recommended in the updated AAPM TG-43 report. The radial dose functions measured with TL sheet are in agreement with those established data of model 6711 {sup 125}I seed and model 6702 {sup 125}I seed at most of the distances within 5% and 7%, respectively. All the measured anisotropy functions showed symmetry about the longitudinal source axis. The anisotropy of dose distributions was clearly present in the immediate vicinity of the source edges. The measured 2D anisotropy function values at 1 cm are in reasonably good agreement with the recommended values. The differences at two points in the 1D anisotropy functions measured with TL sheet and the established data at 1 cm from source center were 0.7% and 1.9% for model 6711 and 6702 {sup 125}I sources, respectively; the differences at 0.5 cm were 1.5% and 1.7% for model 6711 and 6702 {sup 125}I sources, respectively. The relative dosimetric characteristics in the vicinity of actual interstitial brachytherapy sources containing {sup 125}I have been experimentally determined by using the TL sheet as a 2D dosimeter.

  17. Photoluminescence and thermoluminescence properties of Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2} nanophosphor

    SciTech Connect

    Gupta, Palvi; Bedyal, A.K.; Kumar, Vinay; Khajuria, Y.; Lochab, S.P.; Pitale, S.S.; Ntwaeaborwa, O.M.; Swart, H.C.

    2014-12-15

    Energy level diagram of Tb{sup 3+} ion in the K{sub 3}Gd(PO{sub 4}){sub 2} host lattice. - Highlights: • First time, a detailed TL and PL study on undoped and Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2} nanophosphor. • Combustion method was employed to synthesize the Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2} nanophosphor. • Mechanism of excitation and emission in undoped and Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2} nanophosphor was given. - Abstract: Tb{sup 3+} doped nanoparticulate K{sub 3}Gd(PO{sub 4}){sub 2} phosphor was prepared by combustion method using urea as a fuel. The structure, optical and luminescent properties of the phosphor were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and thermoluminescence (TL) spectroscopy. In undoped K{sub 3}Gd(PO{sub 4}){sub 2}, the excitation and emission peaks at 273 nm and 323 nm belongs to the {sup 8}S{sub 7/2} → {sup 6}I{sub J(J=7/2)} and {sup 6}P{sub J(J=7/2)} → {sup 8} S{sub 7/2} transitions of Gd{sup 3+} while green emission was observed in the Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2}. TL study was carried out after exposing the samples to γ-radiations (0.1–5 kGy) in the K{sub 3}Gd(PO{sub 4}){sub 2}:Tb{sup 3+} (1.5 mol%). The calculated kinetic parameters were compared with different methods. The band gap of the phosphor was estimated as 5.80 eV. The green shade of the Tb{sup 3+} ion with the CIE coordinates (x, y) as (0.29, 0.54) was in good agreement with the well known green phosphors.

  18. Virtual Laboratories

    NASA Astrophysics Data System (ADS)

    Hut, P.

    At the frontier of most areas in science, computer simulations playa central role. The traditional division of natural science into experimental and theoretical investigations is now completely outdated. Instead, theory, simulation, and experimentation form three equally essential aspects, each with its own unique flavor and challenges. Yet, education in computational science is still lagging far behind, and the number of text books in this area is minuscule compared to the many text books on theoretical and experimental science. As a result, many researchers still carry out simulations in a haphazard way, without properly setting up the computational equivalent of a well equipped laboratory. The art of creating such a virtual laboratory, while providing proper extensibility and documentation, is still in its infancy. A new approach is described here, Open Knowledge, as an extension of the notion of Open Source software. Besides open source code, manuals, and primers, an open knowledge project provides simulated dialogues between code developers, thus sharing not only the code, but also the motivations behind the code.

  19. Job cuts loom at National Physical Laboratory

    NASA Astrophysics Data System (ADS)

    Extance, Andy

    2016-09-01

    The UK's National Physical Laboratory (NPL) - the country's standards lab - is consulting on making up to 50 compulsory redundancies as it prepares to shift its research priorities towards quantum technologies and big data.

  20. High School Small Animal Laboratory--Business

    ERIC Educational Resources Information Center

    Penn, Alan

    1974-01-01

    An Ohio vocational school Small Animal Care program prepares students for entry level employment as veterinary assistants, pet shop salesmen, kennel workers, animal groomers, Humane Society workers, laboratory animal assistants, and riding stable assistants. (EA)