Sample records for detectors radiation

  1. Radiation detector

    SciTech Connect

    Rifu, T.

    1984-10-16

    A radiation detector adapted to be used with a computerized tomographic apparatus, wherein filters prepared from a radiation-absorbing material are provided on the outside of a radiation-permeable window in the positions facing radiation-detecting cells. The filters compensate for differences between the radiation-detecting properties of the detection cells, thereby equalizing said radiation-detecting properties.

  2. Thallium bromide radiation detectors

    Microsoft Academic Search

    K. S. Shah; J. C. Lund; F. Olschner; L. Moy; M. R. Squillante

    1989-01-01

    Radiation detectors have been fabricated from crystals of the semiconductor material thallium bromide (TlBr) and the performance of these detectors as room temperature photon spectrometers has been measured. These detectors exhibit improved energy resolution over previously reported TlBr detectors. These results indicate that TlBr is a very promising radiation detector material.

  3. Adaptors for radiation detectors

    SciTech Connect

    Livesay, Ronald Jason

    2014-04-22

    Described herein are adaptors and other devices for radiation detectors that can be used to make accurate spectral measurements of both small and large bulk sources of radioactivity, such as building structures, soils, vessels, large equipment, and liquid bodies. Some exemplary devices comprise an adaptor for a radiation detector, wherein the adaptor can be configured to collimate radiation passing through the adapter from an external radiation source to the radiation detector and the adaptor can be configured to enclose a radiation source within the adapter to allow the radiation detector to measure radiation emitted from the enclosed radiation source.

  4. Nuclear radiation detectors

    Microsoft Academic Search

    Luiz Alexandre Schuch; Daniel Jean Roger Nordemann

    1990-01-01

    Detectors of nuclear radiation, such as gaseous detectors, scintillators, and semiconductors, are presented through their general properties and with their operating systems. The semiconductor detectors are studied with more details.

  5. Nuclear Radiation Detectors

    Microsoft Academic Search

    G. A. Morton

    1962-01-01

    Nuclear radiation detectors are required in all the major fields of nuclear science and technology. They fall into two principal categories, single element detectors and imaging detectors. Single element detectors can be classified into four types, based upon their physical mode of operation. These are 1) Scintillation counters, 2) Gas ionization detectors, a) Ionization chambers, b) Proportional counters, c) Geiger-Mueller

  6. Tin Can Radiation Detector.

    ERIC Educational Resources Information Center

    Crull, John L.

    1986-01-01

    Provides instructions for making tin can radiation detectors from empty aluminum cans, aluminum foil, clear plastic, copper wire, silica gel, and fine, unwaxed dental floss put together with tape or glue. Also provides suggestions for activities using the detectors. (JN)

  7. Mossbauer spectrometer radiation detector

    NASA Technical Reports Server (NTRS)

    Singh, J. J. (inventor)

    1973-01-01

    A Mossbauer spectrometer with high efficiencies in both transmission and backscattering techniques is described. The device contains a sodium iodide crystal for detecting radiation caused by the Mossbauer effect, and two photomultipliers to collect the radiation detected by the crystal. When used in the transmission technique, the sample or scatterer is placed between the incident radiation source and the detector. When used in a backscattering technique, the detector is placed between the incident radiation source and the sample of scatterer such that the incident radiation will pass through a hole in the crystal and strike the sample. Diagrams of the instrument are provided.

  8. Microwave Radiation Detector

    NASA Technical Reports Server (NTRS)

    Lesh, J. R.

    1984-01-01

    Direct photon detector responds to microwave frequencies. Method based on trapped-ion frequency-generation standards proposed to detect radio-frequency (RF) radiation at 40.5 GHz. Technique used for directdetection (RF) communication, radar, and radio astronomy.

  9. Underwater radiation detector

    DOEpatents

    Kruse, Lyle W. (Albuquerque, NM); McKnight, Richard P. (Albuquerque, NM)

    1986-01-01

    A detector apparatus for differentiating between gamma and neutron radiation is provided. The detector includes a pair of differentially shielded Geiger-Mueller tubes. The first tube is wrapped in silver foil and the second tube is wrapped in lead foil. Both the silver and lead foils allow the passage of gamma rays at a constant rate in a gamma ray only field. When neutrons are present, however, the silver activates and emits beta radiation that is also detected by the silver wrapped Geiger-Mueller tube while the radiation detected by the lead wrapped Geiger-Mueller tube remains constant. The amount of radiation impinging on the separate Geiger-Mueller tubes is then correlated in order to distinguish between the neutron and gamma radiations.

  10. Radiation Detectors and Art

    NASA Astrophysics Data System (ADS)

    Denker, Andrea

    The use of radiation detectors in the analysis of art objects represents a very special application in a true interdisciplinary field. Radiation detectors employed in this field detect, e.g., x-rays, ?-rays, ? particles, and protons. Analyzed materials range from stones, metals, over porcelain to paintings. The available nondestructive and noninvasive analytical methods cover a broad range of techniques. Hence, for the sake of brevity, this chapter will concentrate on few techniques: Proton Induced X-ray Emission (PIXE) and Proton Induced ?-ray Emission (PIGE).

  11. Amorphous silicon radiation detectors

    DOEpatents

    Street, R.A.; Perez-Mendez, V.; Kaplan, S.N.

    1992-11-17

    Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification. 13 figs.

  12. Amorphous silicon radiation detectors

    DOEpatents

    Street, Robert A. (Palo Alto, CA); Perez-Mendez, Victor (Berkeley, CA); Kaplan, Selig N. (El Cerrito, CA)

    1992-01-01

    Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification.

  13. Ionizing radiation detector

    DOEpatents

    Thacker, Louis H. (Knoxville, TN)

    1990-01-01

    An ionizing radiation detector is provided which is based on the principle of analog electronic integration of radiation sensor currents in the sub-pico to nano ampere range between fixed voltage switching thresholds with automatic voltage reversal each time the appropriate threshold is reached. The thresholds are provided by a first NAND gate Schmitt trigger which is coupled with a second NAND gate Schmitt trigger operating in an alternate switching state from the first gate to turn either a visible or audible indicating device on and off in response to the gate switching rate which is indicative of the level of radiation being sensed. The detector can be configured as a small, personal radiation dosimeter which is simple to operate and responsive over a dynamic range of at least 0.01 to 1000 R/hr.

  14. Transition radiation detectors

    Microsoft Academic Search

    Boris Dolgoshein

    1993-01-01

    The use of transition radiation (TR) as a means of identifying high energy particles has now become a subject of intensive experimental investigations and applications. Our intention is first to study the physics of these phenomena and to describe ways of building detectors which can efficiently identify particles.

  15. Photovoltaic radiation detector element

    DOEpatents

    Agouridis, D.C.

    1980-12-17

    A radiation detector element is formed of a body of semiconductor material, a coating on the body which forms a photovoltaic junction therewith, and a current collector consisting of narrow metallic strips, the aforesaid coating having an opening therein in the edge of which closely approaches but is spaced from the current collector strips.

  16. Semiconductor radiation detector

    DOEpatents

    Patt, Bradley E. (Sherman Oaks, CA); Iwanczyk, Jan S. (Los Angeles, CA); Tull, Carolyn R. (Orinda, CA); Vilkelis, Gintas (Westlake Village, CA)

    2002-01-01

    A semiconductor radiation detector is provided to detect x-ray and light photons. The entrance electrode is segmented by using variable doping concentrations. Further, the entrance electrode is physically segmented by inserting n+ regions between p+ regions. The p+ regions and the n+ regions are individually biased. The detector elements can be used in an array, and the p+ regions and the n+ regions can be biased by applying potential at a single point. The back side of the semiconductor radiation detector has an n+ anode for collecting created charges and a number of p+ cathodes. Biased n+ inserts can be placed between the p+ cathodes, and an internal resistor divider can be used to bias the n+ inserts as well as the p+ cathodes. A polysilicon spiral guard can be implemented surrounding the active area of the entrance electrode or surrounding an array of entrance electrodes.

  17. Handheld CZT radiation detector

    DOEpatents

    Murray, William S.; Butterfield, Kenneth B.; Baird, William

    2004-08-24

    A handheld CZT radiation detector having a CZT gamma-ray sensor, a multichannel analyzer, a fuzzy-logic component, and a display component is disclosed. The CZT gamma-ray sensor may be a coplanar grid CZT gamma-ray sensor, which provides high-quality gamma-ray analysis at a wide range of operating temperatures. The multichannel analyzer categorizes pulses produce by the CZT gamma-ray sensor into channels (discrete energy levels), resulting in pulse height data. The fuzzy-logic component analyzes the pulse height data and produces a ranked listing of radioisotopes. The fuzzy-logic component is flexible and well-suited to in-field analysis of radioisotopes. The display component may be a personal data assistant, which provides a user-friendly method of interacting with the detector. In addition, the radiation detector may be equipped with a neutron sensor to provide an enhanced mechanism of sensing radioactive materials.

  18. Semiconductor radiation detector

    DOEpatents

    Bell, Zane W. (Oak Ridge, TN); Burger, Arnold (Knoxville, TN)

    2010-03-30

    A semiconductor detector for ionizing electromagnetic radiation, neutrons, and energetic charged particles. The detecting element is comprised of a compound having the composition I-III-VI.sub.2 or II-IV-V.sub.2 where the "I" component is from column 1A or 1B of the periodic table, the "II" component is from column 2B, the "III" component is from column 3A, the "IV" component is from column 4A, the "V" component is from column 5A, and the "VI" component is from column 6A. The detecting element detects ionizing radiation by generating a signal proportional to the energy deposited in the element, and detects neutrons by virtue of the ionizing radiation emitted by one or more of the constituent materials subsequent to capture. The detector may contain more than one neutron-sensitive component.

  19. Radiation Hazard Detector

    NASA Technical Reports Server (NTRS)

    1978-01-01

    NASA technology has made commercially available a new, inexpensive, conveniently-carried device for protection, of people exposed to potentially dangerous levels of microwave radiation. Microwaves are radio emissions of extremely high frequency. They can be hazardous but the degree of hazard is not yet well understood. Generally, it is believed that low intensity radiation of short duration is not harmful but that exposure to high levels can induce deep internal burns, affecting the circulatory and nervous systems, and particularly the eyes. The Department of Labor's Occupational Safety and Health Administration (OSHA) has established an allowable safe threshold of exposure. However, people working near high intensity sources of microwave energy-for example, radar antennas and television transmitters-may be unknowingly exposed to radiation levels beyond the safe limit. This poses not only a personal safety problem but also a problem for employers in terms of productivity loss, workman's compensation claims and possible liability litigation. Earlier-developed monitoring devices which warn personnel of dangerous radiation levels have their shortcomings. They can be cumbersome and awkward to use while working. They also require continual visual monitoring to determine if a person is in a dangerous area of radiation, and they are relatively expensive, another deterrent to their widespread adoption. In response to the need for a cheaper and more effective warning system, Jet Propulsion Laboratory developed, under NASA auspices, a new, battery-powered Microwave Radiation Hazard Detector. To bring the product to the commercial market, California Institute Research Foundation, the patent holder, granted an exclusive license to Cicoil Corporation, Chatsworth, California, an electronic components manufacturer.

  20. Semiconductor nuclear radiation detector studies

    Microsoft Academic Search

    A. H. Sher

    1974-01-01

    In response to a problem that arose with regard to the availability of germanium for lithium-drifted germanium detectors (Ge(Li) detectors), a comprehensive program was undertaken aimed toward the development of a method for the rapid specification of germanium quality for nuclear radiation detector use, and the determination of factors affecting germanium quality. Measurements on a large number of germanium crystals,

  1. Radiation damage of germanium detectors

    NASA Technical Reports Server (NTRS)

    Pehl, R. H.

    1978-01-01

    Energetic particles can produce interstitial-vacancy pairs in a crystal by knocking the atoms from their normal positions. Detectors are unique among semiconductor devices in depending on very low concentrations of electrically active impurities, and also on efficient transport of holes and electrons over relatively large distances. Because the dense regions of damage produced by energetic particles may result in donors and/or acceptors, and also provide trapping sites for holes and electrons, detectors are very sensitive to radiation damage. In addition to these effects occurring within the detector, radiation may also change the characteristics of the exposed surfaces causing unpredictable effects on the detector leakage current. Radiation-induced surface degradation has rarely, if ever, been observed for germanium detectors. The possibility of minimizing hole trapping in charge collection by the use of a high-purity germanium coaxial detector configured with the p (+) contact on the coaxial periphery is discussed.

  2. Simple dynamic electromagnetic radiation detector

    NASA Technical Reports Server (NTRS)

    Been, J. F.

    1972-01-01

    Detector monitors gamma dose rate at particular position in a radiation facility where a mixed neutron-gamma environment exists, thus determining reactor power level changes. Device also maps gamma intensity profile across a neutron-gamma beam.

  3. RSSC RADIATION DETECTORS & SURVEY INSTRUMENTS 8/99 4-1 RADIATION DETECTORS AND SURVEY INSTRUMENTS

    E-print Network

    Slatton, Clint

    RSSC RADIATION DETECTORS & SURVEY INSTRUMENTS 8/99 4-1 CHAPTER 4 RADIATION DETECTORS AND SURVEY........................................................................................................... 4-3 II. Use of Radiation Survey Instruments

  4. Radiation detectors in nuclear medicine.

    PubMed

    Ranger, N T

    1999-01-01

    Single-photon-emitting or positron-emitting radionuclides employed in nuclear medicine are detected by using sophisticated imaging devices, whereas simpler detection devices are used to quantify activity for the following applications: measuring doses of radiopharmaceuticals, performing radiotracer bioassays, and monitoring and controlling radiation risk in the clinical environment. Detectors are categorized in terms of function, the physical state of the transducer, or the mode of operation. The performance of a detector is described by the parameters efficiency, energy resolution and discrimination, and dead time. A detector may be used to detect single events (pulse mode) or to measure the rate of energy deposition (current mode). Some detectors are operated as simple counting systems by using a single-channel pulse height analyzer to discriminate against background or other extraneous events. Other detectors are operated as spectrometers and use a multichannel analyzer to form an energy spectrum. The types of detectors encountered in nuclear medicine are gas-filled detectors, scintillation detectors, and semiconductor detectors. The ionization detector, Geiger-Müller detector, extremity and area monitor, dose calibrator, well counter, thyroid uptake probe, Anger scintillation camera, positron emission tomographic scanner, solid-state personnel dosimeter, and intraoperative probe are examples of detectors used in clinical nuclear medicine practice. PMID:10194791

  5. Broadband optical radiation detector

    NASA Technical Reports Server (NTRS)

    Gupta, A.; Hong, S. D.; Moacanin, J. (inventors)

    1981-01-01

    A method and apparatus for detecting optical radiation by optically monitoring temperature changes in a microvolume caused by absorption of the optical radiation to be detected is described. More specifically, a thermal lens forming material is provided which has first and second opposite, substantially parallel surfaces. A reflective coating is formed on the first surface, and a radiation absorbing coating is formed on the reflective coating. Chopped, incoming optical radiation to be detected is directed to irradiate a small portion of the radiation absorbing coating. Heat generated in this small area is conducted to the lens forming material through the reflective coating, thereby raising the temperature of a small portion of the lens forming material and causing a thermal lens to be formed therein.

  6. Cadmium telluride photovoltaic radiation detector

    DOEpatents

    Agouridis, Dimitrios C. (Oak Ridge, TN); Fox, Richard J. (Oak Ridge, TN)

    1981-01-01

    A dosimetry-type radiation detector is provided which employs a polycrystalline, chlorine-compensated cadmium telluride wafer fabricated to operate as a photovoltaic current generator used as the basic detecting element. A photovoltaic junction is formed in the wafer by painting one face of the cadmium telluride wafer with an n-type semiconductive material. The opposite face of the wafer is painted with an electrically conductive material to serve as a current collector. The detector is mounted in a hermetically sealed vacuum containment. The detector is operated in a photovoltaic mode (zero bias) while DC coupled to a symmetrical differential current amplifier having a very low input impedance. The amplifier converts the current signal generated by radiation impinging upon the barrier surface face of the wafer to a voltage which is supplied to a voltmeter calibrated to read quantitatively the level of radiation incident upon the detecting wafer.

  7. Modern detectors for radiation monitors

    Microsoft Academic Search

    A. V. Shumakov; A. S. Sviridov; S. V. Kolesnikov

    2011-01-01

    The possibilities of using modern photon and neutron detectors for developing radiation monitors, specifically, LaBr3, Bi4Ge3O12, CdWO4, LiI, ZnO, Lu2SiO5(Ce), CdTe, and HgI2, microtubes from organic scintillators, nanomaterials, and detectors based on gaseous and solid-state electronic multipliers\\u000a are examined. A comparison is made of conventional detectors based on NaI(Tl) and CsI(Tl), plastic scintillators, and 3He counters. The advantages of the

  8. Portable Radiation Detectors

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Through a Small Business Innovation Research (SBIR) contract from Kennedy Space Center, General Pneumatics Corporation's Western Research Center satisfied a NASA need for a non-clogging Joule-Thomson cryostat to provide very low temperature cooling for various sensors. This NASA-supported cryostat development played a key part in the development of more portable high-purity geranium gamma-ray detectors. Such are necessary to discern between the radionuclides in medical, fuel, weapon, and waste materials. The outcome of the SBIR project is a cryostat that can cool gamma-ray detectors, without vibration, using compressed gas that can be stored compactly and indefinitely in a standby mode. General Pneumatics also produces custom J-T cryostats for other government, commercial and medical applications.

  9. Advanced Space Radiation Detector Technology Development

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Wrbanek, Susan Y.; Fralick, Gustave C.

    2013-01-01

    The advanced space radiation detector development team at NASA Glenn Research Center (GRC) has the goal of developing unique, more compact radiation detectors that provide improved real-time data on space radiation. The team has performed studies of different detector designs using a variety of combinations of solid-state detectors, which allow higher sensitivity to radiation in a smaller package and operate at lower voltage than traditional detectors. Integration of multiple solid-state detectors will result in an improved detector system in comparison to existing state-of-the-art (SOA) instruments for the detection and monitoring of the space radiation field for deep space and aerospace applications.

  10. Advanced Space Radiation Detector Technology Development

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Wrbanek, Susan Y.; Fralick, Gustave C.

    2013-01-01

    The advanced space radiation detector development team at the NASA Glenn Research Center (GRC) has the goal of developing unique, more compact radiation detectors that provide improved real-time data on space radiation. The team has performed studies of different detector designs using a variety of combinations of solid-state detectors, which allow higher sensitivity to radiation in a smaller package and operate at lower voltage than traditional detectors. Integration of multiple solid-state detectors will result in an improved detector system in comparison to existing state-of-the-art instruments for the detection and monitoring of the space radiation field for deep space and aerospace applications.

  11. Advanced Space Radiation Detector Technology Development

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Wrbanek, Susan Y.; Fralick, Gustave C.

    2013-01-01

    The advanced space radiation detector development team at NASA Glenn Research Center (GRC) has the goal of developing unique, more compact radiation detectors that provide improved real-time data on space radiation. The team has performed studies of different detector designs using a variety of combinations of solid-state detectors, which allow higher sensitivity to radiation in a smaller package and operate at lower voltage than traditional detectors. Integration of multiple solid-state detectors will result in an improved detector system in comparison to existing state-of-the-art instruments for the detection and monitoring of the space radiation field for deep space and aerospace applications.

  12. Radiation Detector Materials: An Overview

    SciTech Connect

    Milbrath, Brian D.; Peurrung, Anthony J.; Bliss, Mary; Weber, William J.

    2008-10-10

    This review describes the current state of radiation detection material science, with particular emphasis on national security needs and the goal of identifying the challenges and opportunities that this area represents for the materials science community. Radiation detector materials physics is reviewed, which sets the stage for performance metrics that determine the relative merit of existing and new materials. Semiconductors and scintillators represent the two primary classes of radiation detector materials that are of interest. The state-of-the-art and limitations for each of these materials classes are presented, along with possible avenues of research. Novel materials that could overcome the need for single crystals will also be discussed. Finally, new methods of material discovery and development are put forward – the goal being to provide more predictive guidance and faster screening of candidate materials – and thus ultimately the faster development of superior radiation detection materials.

  13. Flexible composite radiation detector

    DOEpatents

    Cooke, D. Wayne (Santa Fe, NM); Bennett, Bryan L. (Los Alamos, NM); Muenchausen, Ross E. (Los Alamos, NM); Wrobleski, Debra A. (Los Alamos, NM); Orler, Edward B. (Los Alamos, NM)

    2006-12-05

    A flexible composite scintillator was prepared by mixing fast, bright, dense rare-earth doped powdered oxyorthosilicate (such as LSO:Ce, LSO:Sm, and GSO:Ce) scintillator with a polymer binder. The binder is transparent to the scintillator emission. The composite is seamless and can be made large and in a wide variety of shapes. Importantly, the composite can be tailored to emit light in a spectral region that matches the optimum response of photomultipliers (about 400 nanometers) or photodiodes (about 600 nanometers), which maximizes the overall detector efficiency.

  14. Ionizing Radiation Detector

    DOEpatents

    Wright, Gomez W. (Nashville, TN); James, Ralph B. (Livermore, CA); Burger, Arnold (Nashville, TN); Chinn, Douglas A. (Livermore, CA)

    2003-11-18

    A CdZnTe (CZT) crystal provided with a native CdO dielectric coating to reduce surface leakage currents and thereby, improve the resolution of instruments incorporating detectors using CZT crystals is disclosed. A two step process is provided for forming the dielectric coating which includes etching the surface of a CZT crystal with a solution of the conventional bromine/methanol etch treatment, and passivating the CZT crystal surface with a solution of 10 w/o NH.sub.4 F and 10 w/o H.sub.2 O.sub.2 in water after attaching electrical contacts to the crystal surface.

  15. Radiation detector spectrum simulator

    DOEpatents

    Wolf, M.A.; Crowell, J.M.

    1985-04-09

    A small battery operated nuclear spectrum simulator having a noise source generates pulses with a Gaussian distribution of amplitudes. A switched dc bias circuit cooperating therewith to generate several nominal amplitudes of such pulses and a spectral distribution of pulses that closely simulates the spectrum produced by a radiation source such as Americium 241.

  16. Radiation detector spectrum simulator

    DOEpatents

    Wolf, Michael A. (Los Alamos, NM); Crowell, John M. (Los Alamos, NM)

    1987-01-01

    A small battery operated nuclear spectrum simulator having a noise source nerates pulses with a Gaussian distribution of amplitudes. A switched dc bias circuit cooperating therewith generates several nominal amplitudes of such pulses and a spectral distribution of pulses that closely simulates the spectrum produced by a radiation source such as Americium 241.

  17. Compound semiconductor radiation detectors

    Microsoft Academic Search

    Alan Owens; A. Peacock

    2004-01-01

    We discuss the potential benefits of using compound semiconductors for the detection of X- and ?-ray radiation. While Si and Ge have become detection standards for energy dispersive spectroscopy in the laboratory, their use for an increasing range of applications is becoming marginalized by one or more of their physical limitations; namely the need for ancillary cooling systems or bulky

  18. Advanced Radiation Detector Development

    SciTech Connect

    The University of Michigan

    1998-07-01

    Since our last progress report, the project at The University of Michigan has continued to concentrate on the development of gamma ray spectrometers fabricated from cadmium zinc telluride (CZT). This material is capable of providing energy resolution that is superior to that of scintillation detectors, while avoiding the necessity for cooling associated with germanium systems. In our past reports, we have described one approach (the coplanar grid electrode) that we have used to partially overcome some of the major limitations on charge collection that is found in samples of CZT. This approach largely eliminates the effect of hole motion in the formation of the output signal, and therefore leads to pulses that depend only on the motion of a single carrier (electrons). Since electrons move much more readily through CZT than do holes, much better energy resolution can be achieved under these conditions. In our past reports, we have described a 1 cm cube CZT spectrometer fitted with coplanar grids that achieved an energy resolution of 1.8% from the entire volume of the crystal. This still represents, to our knowledge, the best energy resolution ever demonstrated in a CZT detector of this size.

  19. InI nuclear radiation detectors

    Microsoft Academic Search

    M. R. Squillante; C. Zhou; J. Zhang; L. P. Moy; K. S. Shah

    1993-01-01

    Semiconductor radiation detectors are fabricated on single crystal wafers of indium iodide and tested both as direct radiation detectors and as optical detectors coupled to a scintillator crystal. The initial performance of the devices is encouraging but some chemical instability of the crystals is observed. Improvements in the detector performance may be possible by enhancing the InI crystal purity and

  20. JOSEPHSON DETECTORS OF MILLIMETER ELECTROMAGNETIC RADIATION

    E-print Network

    Paris-Sud XI, Université de

    293 JOSEPHSON DETECTORS OF MILLIMETER ELECTROMAGNETIC RADIATION V. A. KULIKOV, N. N. KURDJUMOV, G. 2014 The possibility of construction of high sensitive detectors of electromagnetic radiation is devoted to detectors of electromagnetic radiation in the upper millimeter range, designed for use

  1. A low temperature gravitational radiation detector

    NASA Technical Reports Server (NTRS)

    Hamilton, W. O.

    1971-01-01

    The beginning design of an experiment is discussed for studying gravitational radiation by using massive detectors which are cooled to ultralow temperatures in order to improve the signal to noise ratios and the effective range and stability of the detectors. The gravitational detector, a low detection system, a cooled detector, magnetic support, superconducting shielding, and superconducting accelerometer detector are described.

  2. Transition Radiation Detector in MACRO

    E-print Network

    M. N. Mazziotta; for the MACRO Collaboration

    1999-05-13

    The MACRO detector is located in the Gran Sasso Laboratory. MACRO's overburden varies from 3150 to 7000 hg/cm^2. A transition radiation detector (TRD) has been added to the MACRO detector in order to measure the residual energy of muons entering MACRO, i.e. the energy they have after passing through the Gran Sasso's rock overburden. The TRD consists of three identical modules with a total horizontal area of 36 m^2. The results presented here are referred to single and double events in MACRO with one muon crossing one of the TRD modules. Our data show that double muons are more energetic than single ones, as predicted by the interaction models of primary cosmic rays with the atmosphere.

  3. Plasma Panel Based Radiation Detectors

    SciTech Connect

    Friedman, Dr. Peter S. [Integrated Sensors, LLC; Varner Jr, Robert L [ORNL; Ball, Robert [University of Michigan; Beene, James R [ORNL; Ben Moshe, M. [Tel Aviv University; Benhammou, Yan [Tel Aviv University; Chapman, J. Wehrley [University of Michigan; Etzion, E [Tel Aviv University; Ferretti, Claudio [University of Michigan; Bentefour, E [Ion Beam Applications; Levin, Daniel S. [University of Michigan; Moshe, M. [Tel Aviv University; Silver, Yiftah [Tel Aviv University; Weaverdyck, Curtis [University of Michigan; Zhou, Bing [University of Michigan

    2013-01-01

    The plasma panel sensor (PPS) is a gaseous micropattern radiation detector under current development. It has many operational and fabrication principles common to plasma display panels (PDPs). It comprises a dense matrix of small, gas plasma discharge cells within a hermetically sealed panel. As in PDPs, it uses non-reactive, intrinsically radiation-hard materials such as glass substrates, refractory metal electrodes, and mostly inert gas mixtures. We are developing these devices primarily as thin, low-mass detectors with gas gaps from a few hundred microns to a few millimeters. The PPS is a high gain, inherently digital device with the potential for fast response times, fine position resolution (< 50 m RMS) and low cost. In this paper we report here on prototype PPS experimental results in detecting betas, protons and cosmic muons, and we extrapolate on the PPS potential for applications including detection of alphas, heavy-ions at low to medium energy, thermal neutrons and X-rays.

  4. Direct detector for terahertz radiation

    DOEpatents

    Wanke, Michael C. (Albuquerque, NM); Lee, Mark (Albuquerque, NM); Shaner, Eric A. (Albuquerque, NM); Allen, S. James (Santa Barbara, CA)

    2008-09-02

    A direct detector for terahertz radiation comprises a grating-gated field-effect transistor with one or more quantum wells that provide a two-dimensional electron gas in the channel region. The grating gate can be a split-grating gate having at least one finger that can be individually biased. Biasing an individual finger of the split-grating gate to near pinch-off greatly increases the detector's resonant response magnitude over prior QW FET detectors while maintaining frequency selectivity. The split-grating-gated QW FET shows a tunable resonant plasmon response to FIR radiation that makes possible an electrically sweepable spectrometer-on-a-chip with no moving mechanical optical parts. Further, the narrow spectral response and signal-to-noise are adequate for use of the split-grating-gated QW FET in a passive, multispectral terahertz imaging system. The detector can be operated in a photoconductive or a photovoltaic mode. Other embodiments include uniform front and back gates to independently vary the carrier densities in the channel region, a thinned substrate to increase bolometric responsivity, and a resistive shunt to connect the fingers of the grating gate in parallel and provide a uniform gate-channel voltage along the length of the channel to increase the responsivity and improve the spectral resolution.

  5. Advanced concepts for semiconductor nuclear radiation detectors

    Microsoft Academic Search

    J. Kemmer

    1990-01-01

    By applying the technologies of semiconductor device fabrication, new types of Si radiation detectors have been developed. These include low-noise detectors for energy spectroscopy as well as detectors for precise position measurement of radiation. The activities on smart sensors resulted in detectors with on-chip low-noise signal amplification. One of the most interesting ideas is a random-access pixel detector with charge

  6. 49 CFR 173.310 - Exceptions for radiation detectors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Exceptions for radiation detectors. 173.310 Section 173.310 ...Preparation and Packaging § 173.310 Exceptions for radiation detectors. Radiation detectors, radiation sensors, electron tube...

  7. 49 CFR 173.310 - Exceptions for radiation detectors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Exceptions for radiation detectors. 173.310 Section 173.310 ...Preparation and Packaging § 173.310 Exceptions for radiation detectors. Radiation detectors, radiation sensors, electron tube...

  8. 49 CFR 173.310 - Exceptions for radiation detectors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Exceptions for radiation detectors. 173.310 Section 173.310 ...Preparation and Packaging § 173.310 Exceptions for radiation detectors. Radiation detectors, radiation sensors, electron tube...

  9. 49 CFR 173.310 - Exceptions for radiation detectors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Exceptions for radiation detectors. 173.310 Section 173.310 ...Preparation and Packaging § 173.310 Exceptions for radiation detectors. Radiation detectors, radiation sensors, electron tube...

  10. 49 CFR 173.310 - Exceptions for radiation detectors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Exceptions for radiation detectors. 173.310 Section 173.310 ...Preparation and Packaging § 173.310 Exceptions for radiation detectors. Radiation detectors, radiation sensors, electron tube...

  11. Transition Radiation Detector to Search for Dark Matter in Space

    E-print Network

    Roma "La Sapienza", Università di

    The AMS-02 Transition Radiation Detector to Search for Dark Matter in Space The AMSThe AMS--0202 Transition Radiation DetectorTransition Radiation Detector to Search for Dark Matter in Spaceto Search.it On behalf of the AMS collaboration Transition Radiation DetectorTransition Radiation Detector Transition

  12. Semiconductor nuclear radiation detector studies. Final report

    Microsoft Academic Search

    Sher

    1974-01-01

    In response to a problem that arose with regard to the availability of ; germanium for lithium-drifted germanium detectors (Ge(Li) detectors), a ; comprehensive program was undertaken aimed toward the development of a method for ; the rapid specification of germanium quality for nuclear radiation detector use, ; and the determination of factors affecting germanium quality. Measurements on a ;

  13. Radiation damage effects on solid state detectors

    NASA Technical Reports Server (NTRS)

    Trainor, J. H.

    1972-01-01

    Totally depleted silicon diodes are discussed which are used as nuclear particle detectors in investigations of galactic and solar cosmic radiation and trapped radiation. A study of radiation and chemical effects on the diodes was conducted. Work on electron and proton irradiation of surface barrier detectors with thicknesses up to 1 mm was completed, and work on lithium-drifted silicon devices with thicknesses of several millimeters was begun.

  14. Radiation detectors in medical and biological applications

    NASA Astrophysics Data System (ADS)

    Besch, H. J.

    1998-12-01

    Basic definitions of imaging theory are given and their importance for detector development is demonstrated. Developments in two-dimensional and scanning radiographic systems are discussed. The substantial progress in non-invasive coronary angiography with synchrotron radiation is presented together with a comparison of the performance of a gaseous and a silicon detector. Synchrotron radiation is also applied in mammography. New modalities making use of coherence are discussed. Non-radiative methods competing with X-ray systems are also presented. Detectors for nuclear medicine and biological structure research are briefly mentioned.

  15. Electron gas grid semiconductor radiation detectors

    DOEpatents

    Lee, Edwin Y. (Livermore, CA); James, Ralph B. (Livermore, CA)

    2002-01-01

    An electron gas grid semiconductor radiation detector (EGGSRAD) useful for gamma-ray and x-ray spectrometers and imaging systems is described. The radiation detector employs doping of the semiconductor and variation of the semiconductor detector material to form a two-dimensional electron gas, and to allow transistor action within the detector. This radiation detector provides superior energy resolution and radiation detection sensitivity over the conventional semiconductor radiation detector and the "electron-only" semiconductor radiation detectors which utilize a grid electrode near the anode. In a first embodiment, the EGGSRAD incorporates delta-doped layers adjacent the anode which produce an internal free electron grid well to which an external grid electrode can be attached. In a second embodiment, a quantum well is formed between two of the delta-doped layers, and the quantum well forms the internal free electron gas grid to which an external grid electrode can be attached. Two other embodiments which are similar to the first and second embodiment involve a graded bandgap formed by changing the composition of the semiconductor material near the first and last of the delta-doped layers to increase or decrease the conduction band energy adjacent to the delta-doped layers.

  16. Development of a silicon carbide radiation detector

    Microsoft Academic Search

    F. H. Ruddy; A. R. Dulloo; J. G. Seidel; S. Seshadri; L. B. Rowland

    1998-01-01

    The radiation detection properties of semiconductor detectors made of 4H silicon carbide were evaluated. Both Schottky and p-n junction devices were tested. Exposure to alpha particles from a 238Pu source led to robust signals from the detectors. The resolution of the Schottky SiC detector was 5.8% (FWHM) at an energy of 294 keV, while that of the p-n junction was

  17. Characteristics of radiation detectors for diagnostic radiology

    Microsoft Academic Search

    Larry A. DeWerd; Louis K. Wagner

    1999-01-01

    The use of X-rays for diagnosis has been significant since its discovery. A measurement of the X-ray dose is the main determinant for risk vs benefit of these examinations. Radiation detectors are important for dose measurement. A description of these detectors, including the most frequently used ionization chamber, aids in the understanding necessary for their use. Proper and accurate use

  18. Enhanced radiation detectors using luminescent materials

    DOEpatents

    Vardeny, Zeev V. (Holladay, UT); Jeglinski, Stefan A. (Durham, NC); Lane, Paul A. (Sheffield, GB)

    2001-01-01

    A radiation detecting device comprising a radiation sensing element, and a layer of luminescent material to expand the range of wavelengths over which the sensing element can efficiently detect radiation. The luminescent material being selected to absorb radiation at selected wavelengths, causing the luminescent material to luminesce, and the luminescent radiation being detected by the sensing element. Radiation sensing elements include photodiodes (singly and in arrays), CCD arrays, IR detectors and photomultiplier tubes. Luminescent materials include polymers, oligomers, copolymers and porphyrines, Luminescent layers include thin films, thicker layers, and liquid polymers.

  19. Wafer-fused semiconductor radiation detector

    DOEpatents

    Lee, Edwin Y. (Livermore, CA); James, Ralph B. (Livermore, CA)

    2002-01-01

    Wafer-fused semiconductor radiation detector useful for gamma-ray and x-ray spectrometers and imaging systems. The detector is fabricated using wafer fusion to insert an electrically conductive grid, typically comprising a metal, between two solid semiconductor pieces, one having a cathode (negative electrode) and the other having an anode (positive electrode). The wafer fused semiconductor radiation detector functions like the commonly used Frisch grid radiation detector, in which an electrically conductive grid is inserted in high vacuum between the cathode and the anode. The wafer-fused semiconductor radiation detector can be fabricated using the same or two different semiconductor materials of different sizes and of the same or different thicknesses; and it may utilize a wide range of metals, or other electrically conducting materials, to form the grid, to optimize the detector performance, without being constrained by structural dissimilarity of the individual parts. The wafer-fused detector is basically formed, for example, by etching spaced grooves across one end of one of two pieces of semiconductor materials, partially filling the grooves with a selected electrical conductor which forms a grid electrode, and then fusing the grooved end of the one semiconductor piece to an end of the other semiconductor piece with a cathode and an anode being formed on opposite ends of the semiconductor pieces.

  20. NUCLEAR RADIATION DETECTOR HAVING ELECTROSTATICALLY CHARGEABLE ELEMENTS

    Microsoft Academic Search

    Shriner

    1963-01-01

    An ionizing radiation detector that is inexpensive and requires no ; outside source of electric current for recharging is described. The device is ; activated by shaking that develops electric charge of opposite polarities on the ; walls of an ionization chamber and on free-floating elements within the chamber. ; Ionizing radiation causes a proportional decrease of the electrostatic charge,

  1. Device for calibrating a radiation detector system

    DOEpatents

    McFee, M.C.; Kirkham, T.J.; Johnson, T.H.

    1994-12-27

    A device is disclosed for testing a radiation detector system that includes at least two arrays of radiation detectors that are movable with respect to each other. The device includes a ''shield plate'' or shell, and an opposing ''source plate'' containing a source of ionizing radiation. Guides are attached to the outer surface of the shell for engaging the forward ends of the detectors, thereby reproducibly positioning the detectors with respect to the source and with respect to each other, thereby ensuring that a predetermined portion of the radiation emitted by the source passes through the shell and reaches the detectors. The shell is made of an hydrogenous material having approximately the same radiological attenuation characteristics as composite human tissue. The source represents a human organ such as the lungs, heart, kidneys, liver, spleen, pancreas, thyroid, testes, prostate, or ovaries. The source includes a source of ionizing radiation having a long half-life and an activity that is within the range typically searched for in human subjects. 3 figures.

  2. Device for calibrating a radiation detector system

    DOEpatents

    Mc Fee, Matthew C. (New Ellenton, SC); Kirkham, Tim J. (Beech Island, SC); Johnson, Tippi H. (Aiken, SC)

    1994-01-01

    A device for testing a radiation detector system that includes at least two arrays of radiation detectors that are movable with respect to each other. The device includes a "shield plate" or shell, and an opposing "source plate" containing a source of ionizing radiation. Guides are attached to the outer surface of the shell for engaging the forward ends of the detectors, thereby reproducibly positioning the detectors with respect to the source and with respect to each other, thereby ensuring that a predetermined portion of the radiation emitted by the source passes through the shell and reaches the detectors. The shell is made of an hydrogenous material having approximately the same radiological attenuation characteristics as composite human tissue. The source represents a human organ such as the lungs, heart, kidneys, heart, liver, spleen, pancreas, thyroid, testes, prostate, or ovaries. The source includes a source of ionizing radiation having a long half-life and an activity that is within the range typically searched for in human subjects.

  3. Semiconductor high-energy radiation scintillation detector

    Microsoft Academic Search

    A. Kastalsky; S. Luryi; B. Spivak

    2006-01-01

    We propose a new scintillation-type detector in which high-energy radiation generates electron–hole pairs in a direct-gap semiconductor material that subsequently recombine producing infrared light to be registered by a photo-detector. The key issue is how to make the semiconductor essentially transparent to its own infrared light, so that photons generated deep inside the semiconductor could reach its surface without tangible

  4. Radiation and particle detector and amplifier

    NASA Technical Reports Server (NTRS)

    Schmidt, K. C. (inventor)

    1973-01-01

    A radiation or charged particle detector is described which incorporates a channel multiplier structure to amplify the detected rays or particles. The channel multiplier structure has a support multiplying element with a longitudinal slot along one side. The element supports a pair of plates positioned contiguous with the slot. The plates funnel the particles or rays to be detected into the slotted aperture and the element, thus creating an effectively wide aperture detector of the windowless type.

  5. Thallium Bromide Nuclear Radiation Detector Development

    Microsoft Academic Search

    Alexei V. Churilov; Guido Ciampi; Hadong Kim; Leonard J. Cirignano; William M. Higgins; Fred Olschner; Kanai S. Shah

    2009-01-01

    Thallium bromide (TlBr) is a dense, high-Z, wide bandgap semiconductor that has potential as an efficient, compact, room temperature nuclear radiation detector. In this paper we report on our recent progress in TlBr nuclear detector development. In particular, improvements in material purification have led to an order of magnitude increase in the mobility-lifetime product of electrons, (mutau)e, to as high

  6. Semiconductor detector as ionising radiation dosimeter

    NASA Astrophysics Data System (ADS)

    Yunusov, M. S.; Akhmadaliev, A.; Begmatov, K. A.

    1995-09-01

    There are presented the results of processing of ?-irradiation power detector, which possesses high stabilitiy of working parameters. The possibility of its application as a radiation intensimeter and as an absorbed dose dosimeter simultaneously is also discussed. It has been showen that the obtained high stability of parameters of p-Si (the concentration and the life-time of carriers) influenced by doping with Ir allows to use the detectors as a dosimeter of high absorbed doses of ionizing radiation. The ways of rising of the lower limit of dosimeters sensibility to biological absorbed dose are discussed as well. The concrete solution of this problem is suggested.

  7. Metallisation of single crystal diamond radiation detectors

    NASA Astrophysics Data System (ADS)

    Ong, Lucas; Ganesan, Kumaravelu; Alves, Andrew; Barberio, Elisabetta

    2012-10-01

    Properties such as a large band gap, high thermal conductivity and resistance to radiation damage make diamond an extremely attractive candidate for detectors in next generation particle physics experiments. This paper presents our technique for metallisation of a single crystal diamond grown by chemical vapour deposition (CVD) for use as a radiation detector, suitable for operation in places such as the Large Hadron Collider. The front and back side of the diamond are metalised with aluminium and gold on top of titanium respectively, after which the diamond is mounted and read out via a charge sensitive preamplifier. The device is found to collect charge at an efficiency of 97%.

  8. Low-Power Multi-Aspect Space Radiation Detector System

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Wrbanek, Susan Y.; Fralick, Gustave; Freeman, Jon C.; Burkebile, Stephen P.

    2012-01-01

    The advanced space radiation detector development team at NASA Glenn Research Center (GRC) has the goal of developing unique, more compact radiation detectors that provide improved real-time data on space radiation. The team has performed studies of different detector designs using a variety of combinations of solid-state detectors, which allow higher sensitivity to radiation in a smaller package and operate at lower voltage than traditional detectors. Integration of all of these detector technologies will result in an improved detector system in comparison to existing state-of-the-art (SOA) instruments for the detection and monitoring of the deep space radiation field.

  9. Development of Carbon Nanotube based radiation detectors

    NASA Astrophysics Data System (ADS)

    Ambrosio, A.; Ambrosio, M.; Ambrosone, G.; Coscia, U.; Gesuele, F.; Maddalena, P.; Perillo, E.; Raulo, A.; Ugolino, U.

    2007-10-01

    Multi Wall Carbon NanoTubes (MWCNT) are one-dimensional structures with diameters ranging between 5 and 30 nm and lengths up to hundreds of micrometers. They show a metallic-like behaviour and enhanced field emission capability; their sensitivity to the radiation is very peculiar, depending on their diameter and chirality. The wide range of their bandgaps (from 0.4 to ? 6 eV) makes these devices very suitable for fabrication of sensors of electromagnetic radiation, from UV to IR. This opens the possibility to build wide sensitive range radiation detectors for space researches and environmental controls. Preliminary tests have been performed by exposing a prototype detector made up of a MWCNT carpet grown by the CVD technique between two gold electrodes on a 500 micrometer thick silicon substrate to pulsed UV, visible and IR radiation. First results on the charge generated by pulsed laser are reported.

  10. Imaging radiation detector with gain

    DOEpatents

    Morris, C.L.; Idzorek, G.C.; Atencio, L.G.

    1982-07-21

    A radiation imaging device which has application in x-ray imaging. The device can be utilized in CAT scanners and other devices which require high sensitivity and low x-ray fluxes. The device utilizes cumulative multiplication of charge carriers on the anode plane and the collection of positive ion charges to image the radiation intensity on the cathode plane. Parallel and orthogonal cathode wire arrays are disclosed as well as a two-dimensional grid pattern for collecting the positive ions on the cathode.

  11. Imaging radiation detector with gain

    DOEpatents

    Morris, Christopher L. (Los Alamos, NM); Idzorek, George C. (Los Alamos, NM); Atencio, Leroy G. (Espanola, NM)

    1984-01-01

    A radiation imaging device which has application in x-ray imaging. The device can be utilized in CAT scanners and other devices which require high sensitivity and low x-ray fluxes. The device utilizes cumulative multiplication of charge carriers on the anode plane and the collection of positive ion charges to image the radiation intensity on the cathode plane. Parallel and orthogonal cathode wire arrays are disclosed as well as a two-dimensional grid pattern for collecting the positive ions on the cathode.

  12. BIBLIOGRAPHY ON SEMICONDUCTOR NUCLEAR RADIATION DETECTORS

    Microsoft Academic Search

    1958-01-01

    This bibliography consists of 72 references from the published ; literature on the potential uses of semiconductors as nuclear radiation detectors. ; Most references on the uses of cadmium sulfide have been omitted, except for ; recent articles, because excellent bibliographies have already been prepared. ; (auth);

  13. Integrator Circuitry for Single Channel Radiation Detector

    NASA Technical Reports Server (NTRS)

    Holland, Samuel D. (Inventor); Delaune, Paul B. (Inventor); Turner, Kathryn M. (Inventor)

    2008-01-01

    Input circuitry is provided for a high voltage operated radiation detector to receive pulses from the detector having a rise time in the range of from about one nanosecond to about ten nanoseconds. An integrator circuit, which utilizes current feedback, receives the incoming charge from the radiation detector and creates voltage by integrating across a small capacitor. The integrator utilizes an amplifier which closely follows the voltage across the capacitor to produce an integrator output pulse with a peak value which may be used to determine the energy which produced the pulse. The pulse width of the output is stretched to approximately 50 to 300 nanoseconds for use by subsequent circuits which may then use amplifiers with lower slew rates.

  14. Workshop on detectors for synchrotron radiation

    SciTech Connect

    Robinson, Arthur L.

    2000-11-22

    Forefront experiments in many scientific areas for which synchrotron sources provide sufficient flux are nonetheless hindered because detectors cannot collect data fast enough, do not cover sufficiently solid angle, or do no have adequate resolution. Overall, the synchrotron facilities, each of which represents collective investments from funding agencies and user institutions ranging from many hundreds of millions to more than a billion dollars, are effectively significantly underutilized. While this chronic and growing problem plagues facilities around the world, it is particularly acute in the United States, where detector research often has to ride on the coat tails of explicitly science-oriented projects. As a first step toward moving out of this predicament, scientists from the U.S. synchrotron facilities held a national workshop in Washington, DC, on October 30-31, 2000. The Workshop on Detectors for Synchrotron Research aimed to create a national ''roadmap'' for development of synchrotron-radiation detectors.

  15. Radiation detectors: needs and prospects

    SciTech Connect

    Armantrout, G.A.

    1981-01-01

    Important applications for x- and ..gamma..-ray spectroscopy are found in prospecting, materials characterization, environmental monitoring, the life sciences, and nuclear physics. The specific requirements vary for each application with varying degrees of emphasis on either spectrometer resolution, detection efficiency, or both. Since no one spectrometer is ideally suited to this wide range of needs, compromises are usually required. Gas and scintillation spectrometers have reached a level of maturity, and recent interest has concentrated on semiconductor spectrometers. Germanium detectors are showing continuing refinement and are the spectrometers of choice for high resolution applications. The new high-Z semiconductors, such as CdTe and HgI/sub 2/, have shown steady improvement but are limited in both resolution and size and will likely be used only in applications which require their unique properties.

  16. High resolution amorphous silicon radiation detectors

    DOEpatents

    Street, Robert A. (Palo Alto, CA); Kaplan, Selig N. (El Cerrito, CA); Perez-Mendez, Victor (Berkeley, CA)

    1992-01-01

    A radiation detector employing amorphous Si:H cells in an array with each detector cell having at least three contiguous layers (n type, intrinsic, p type), positioned between two electrodes to which a bias voltage is applied. An energy conversion layer atop the silicon cells intercepts incident radiation and converts radiation energy to light energy of a wavelength to which the silicon cells are responsive. A read-out device, positioned proximate to each detector element in an array allows each such element to be interrogated independently to determine whether radiation has been detected in that cell. The energy conversion material may be a layer of luminescent material having a columnar structure. In one embodiment a column of luminescent material detects the passage therethrough of radiation to be detected and directs a light beam signal to an adjacent a-Si:H film so that detection may be confined to one or more such cells in the array. One or both electrodes may have a comb structure, and the teeth of each electrode comb may be interdigitated for capacitance reduction. The amorphous Si:H film may be replaced by an amorphous Si:Ge:H film in which up to 40 percent of the amorphous material is Ge. Two dimensional arrays may be used in X-ray imaging, CT scanning, crystallography, high energy physics beam tracking, nuclear medicine cameras and autoradiography.

  17. High resolution amorphous silicon radiation detectors

    DOEpatents

    Street, R.A.; Kaplan, S.N.; Perez-Mendez, V.

    1992-05-26

    A radiation detector employing amorphous Si:H cells in an array with each detector cell having at least three contiguous layers (n-type, intrinsic, p-type), positioned between two electrodes to which a bias voltage is applied. An energy conversion layer atop the silicon cells intercepts incident radiation and converts radiation energy to light energy of a wavelength to which the silicon cells are responsive. A read-out device, positioned proximate to each detector element in an array allows each such element to be interrogated independently to determine whether radiation has been detected in that cell. The energy conversion material may be a layer of luminescent material having a columnar structure. In one embodiment a column of luminescent material detects the passage therethrough of radiation to be detected and directs a light beam signal to an adjacent a-Si:H film so that detection may be confined to one or more such cells in the array. One or both electrodes may have a comb structure, and the teeth of each electrode comb may be interdigitated for capacitance reduction. The amorphous Si:H film may be replaced by an amorphous Si:Ge:H film in which up to 40 percent of the amorphous material is Ge. Two dimensional arrays may be used in X-ray imaging, CT scanning, crystallography, high energy physics beam tracking, nuclear medicine cameras and autoradiography. 18 figs.

  18. Status of radiation detector and neutron monitor technology

    E-print Network

    Kim, Y K; Ha, J H; Han, S H; Hong, S B; Hwang, I K; Lee, W G; Moon, B S; Park, S H; Song, M H

    2002-01-01

    In this report, we describe the current states of the radiation detection technology, detectors for industrial application, and neutron monitors. We also survey the new technologies being applied to this field. The method to detect radiation is the measurement of the observable secondary effect from the interaction between incident radiation and detector material, such as ionization, excitation, fluorescence, and chemical reaction. The radiation detectors can be categorized into gas detectors, scintillation detectors, and semiconductor detectors according to major effects and main applications. This report contains the current status and operational principles of these detectors. The application fields of radiation detectors are industrial measurement system, in-core neutron monitor, medical radiation diagnostic device, nondestructive inspection device, environmental radiation monitoring, cosmic-ray measurement, security system, fundamental science experiment, and radiation measurement standardization. The st...

  19. Alpha-beta radiation detector

    DOEpatents

    Fleming, Dale M. (Richland, WA); Simmons, Kevin L. (Kennewick, WA); Froelich, Thomas J. (West Richland, WA); Carter, Gregory L. (Richland, WA)

    1998-01-01

    The invention is based in part on the discovery that a plastic housing that is lightweight is surprisingly efficient inasmuch as background signals from any gamma radiation are significantly reduced by using a plastic housing instead of a metal housing. A further aspect of the present invention is the profile of the housing as a bi-linear approximation to a parabola resulting in full optical response from any location on the scintillation material to the photomultiplier tube. A yet further aspect of the present invention is that the survey probe is resistant to magnetic fields. A yet further aspect of the present invention is the use of a snap-fit retaining bracket that overcomes the need for multiple screws.

  20. Alpha-beta radiation detector

    DOEpatents

    Fleming, D.M.; Simmons, K.L.; Froelich, T.J.; Carter, G.L.

    1998-08-18

    The invention is based in part on the discovery that a plastic housing that is lightweight is surprisingly efficient inasmuch as background signals from any gamma radiation are significantly reduced by using a plastic housing instead of a metal housing. A further aspect of the present invention is the profile of the housing as a bi-linear approximation to a parabola resulting in full optical response from any location on the scintillation material to the photomultiplier tube. A yet further aspect of the present invention is that the survey probe is resistant to magnetic fields. A yet further aspect of the present invention is the use of a snap-fit retaining bracket that overcomes the need for multiple screws. 16 figs.

  1. Development of a plasma panel radiation detector

    NASA Astrophysics Data System (ADS)

    Ball, R.; Beene, J. R.; Ben-Moshe, M.; Benhammou, Y.; Bensimon, B.; Chapman, J. W.; Etzion, E.; Ferretti, C.; Friedman, P. S.; Levin, D. S.; Silver, Y.; Varner, R. L.; Weaverdyck, C.; Wetzel, R.; Zhou, B.; Anderson, T.; McKinny, K.; Bentefour, E. H.

    2014-11-01

    This article reports on the development and experimental results of commercial plasma display panels adapted for their potential use as micropattern gas radiation detectors. The plasma panel sensor (PPS) design and materials include glass substrates, metal electrodes and inert gas mixtures which provide a physically robust, hermetically sealed device. Plasma display panels used as detectors were tested with cosmic ray muons, beta rays and gamma rays, protons, and thermal neutrons. The results demonstrated rise times and time resolution of a few nanoseconds, as well as sub-millimeter spatial resolution compatible with the pixel pitch.

  2. Development of a plasma panel radiation detector

    SciTech Connect

    Ball, Robert [University of Michigan; Beene, James R [ORNL; Ben Moshe, M. [Tel Aviv University; Benhammou, Yan [Tel Aviv University; Bensimon, B [Tel Aviv University; Chapman, J. Wehrley [University of Michigan; Etzion, E [Tel Aviv University; Ferretti, Claudio [University of Michigan; Friedman, Dr. Peter S. [Integrated Sensors, LLC; Levin, Daniel S. [University of Michigan; Silver, Yiftah [Tel Aviv University; Weaverdyck, Curtis [University of Michigan; Wetzel, R. [University of Michigan; Zhou, Bing [University of Michigan; Anderson, T [GE Measurement and Control Solutions; McKinny, K [GE Measurement and Control Solutions; Bentefour, E [Ion Beam Applications

    2014-01-01

    This article reports on the development and experimental results of commercial plasma display panels adapted for their potential use as micropattern gas radiation detectors. The plasma panel sensor (PPS) design and materials include glass substrates, metal electrodes and inert gas mixtures which provide a physically robust, hermetically sealed device. Plasma display panels used as detectors were tested with cosmic ray muons, beta rays and gamma rays, protons, and thermal neutrons. The results demonstrated rise times and time resolution of a few nanoseconds, as well as sub-millimeter spatial resolution compatible with the pixel pitch.

  3. Electromagnetic Radiation Hardness of Diamond Detectors

    E-print Network

    T. Behnke; M. Doucet; N. Ghodbane; A. Imhof; C. Martinez; W. Zeuner

    2001-08-22

    The behavior of artificially grown CVD diamond films under intense electromagnetic radiation has been studied. The properties of irradiated diamond samples have been investigated using the method of thermally stimulated current and by studying their charge collection properties. Diamonds have been found to remain unaffected after doses of 6.8 MGy of 10 keV photons and 10 MGy of MeV-range photons. This observation makes diamond an attractive detector material for a calorimeter in the very forward region of the proposed TESLA detector.

  4. Development of a plasma panel radiation detector

    E-print Network

    R. Ball; J. R. Beene; M. Ben-Moshe; Y. Benhammou; R. Bensimon; J. W. Chapman; E. Etzion; C. Ferretti; P. S. Friedman; D. S. Levin; Y. Silver; R. L. Varner; C. Weaverdyck; R. Wetzel; B. Zhou; T. Anderson; K. McKinny; E. H. Bentefour

    2014-06-14

    This article reports on the development and experimental results of commercial plasma display panels adapted for their potential use as micropattern gas radiation detectors. The plasma panel sensors (PPS) design an materials include glass substrates, metal electrodes and inert gas mixtures which provide a physically robust, hermetically-sealed device. Plasma display panels used as detectors were tested with cosmic ray muons, beta rays and gamma rays, protons and thermal neutrons. The results demonstrated rise times and time resolution of a few nanoseconds, as well as sub-millimeter spatial resolution compatible with the pixel pitch.

  5. Advances in gas avalanche radiation detectors for biomedical applications

    E-print Network

    Advances in gas avalanche radiation detectors for biomedical applications A. Breskin* Department avalanche radiation detectors have been massively employed over the past decades, mostly in particle physics on Applications of Radiation Detectors in Medicine, Biology and Astrophysics. Siegen, Germany, October 6}8, 1999

  6. Surface wave chemical detector using optical radiation

    DOEpatents

    Thundat, Thomas G.; Warmack, Robert J.

    2007-07-17

    A surface wave chemical detector comprising at least one surface wave substrate, each of said substrates having a surface wave and at least one measurable surface wave parameter; means for exposing said surface wave substrate to an unknown sample of at least one chemical to be analyzed, said substrate adsorbing said at least one chemical to be sensed if present in said sample; a source of radiation for radiating said surface wave substrate with different wavelengths of said radiation, said surface wave parameter being changed by said adsorbing; and means for recording signals representative of said surface wave parameter of each of said surface wave substrates responsive to said radiation of said different wavelengths, measurable changes of said parameter due to adsorbing said chemical defining a unique signature of a detected chemical.

  7. Plasma panel-based radiation detectors

    E-print Network

    Peter Friedman; Robert Ball; James Beene; Yan Benhammou; Meny Ben-Moshe; Hassan Bentefour; J. W. Chapman; Erez Etzion; Claudio Ferretti; Daniel Levin; Yiftah Silver; Robert Varner; Curtis Weaverdyck; Bing Zhou

    2013-05-10

    The plasma panel sensor (PPS) is a gaseous micropattern radiation detector under current development. It has many operational and fabrication principles common to plasma display panels. It comprises a dense matrix of small, gas plasma discharge cells within a hermetically sealed panel. As in plasma display panels, it uses nonreactive, intrinsically radiation-hard materials such as glass substrates, refractory metal electrodes, and mostly inert gas mixtures. We are developing these devices primarily as thin, low-mass detectors with gas gaps from a few hundred microns to a few millimeters. The PPS is a high gain, inherently digital device with the potential for fast response times, fine position resolution (<50-mm RMS) and low cost. In this paper, we report on prototype PPS experimental results in detecting betas, protons, and cosmic muons, and we extrapolate on the PPS potential for applications including the detection of alphas, heavy ions at low-to-medium energy, thermal neutrons, and X-rays.

  8. Radiation detector having radiation source position detecting means

    SciTech Connect

    Hanawa, M.

    1984-10-09

    Disclosed is a radiation detector provided at both ends with radiation source position detecting means each including three to five electrode plates in which a bias electrode plate centrally disposed has cover layers on both surfaces, and signal electrode plates disposed on both sides of the bias electrode plate each have a cover layer on only one surface farther from the bias electrode plate. Material of the cover layer has a smaller secondary electron emissive power than that of the material of the electrode plates with respect to incident radiation.

  9. Coherent Transition Radiation in Askaryan radio detectors

    E-print Network

    de Vries, Krijn D; van Eijndhoven, Nick; Meures, Thomas; O'Murchadha, Aongus; Scholten, Olaf

    2015-01-01

    We discuss the coherent transition radiation emitted by a macroscopic bunch of particles with a net charge traversing the boundary of two different media. The obtained expression is compared to the emission from a relativistically moving steady charge, as well the emission from a time-varying charge or current. As a first application, we discuss the transition radiation from high-energy cosmic-ray induced air showers hitting Earth's surface before the cascade has died out in the atmosphere. The induced emission gives rise to a radio signal which should be detectable in the currently operating Askaryan radio detectors built to search for the GZK neutrino flux.

  10. Radiation response issues for infrared detectors

    NASA Technical Reports Server (NTRS)

    Kalma, Arne H.

    1990-01-01

    Researchers describe the most important radiation response issues for infrared detectors. In general, the two key degradation mechanisms in infrared detectors are the noise produced by exposure to a flux of ionizing particles (e.g.; trapped electronics and protons, debris gammas and electrons, radioactive decay of neutron-activated materials) and permanent damage produced by exposure to total dose. Total-dose-induced damage is most often the result of charge trapping in insulators or at interfaces. Exposure to short pulses of ionization (e.g.; prompt x rays or gammas, delayed gammas) will cause detector upset. However, this upset is not important to a sensor unless the recovery time is too long. A few detector technologies are vulnerable to neutron-induced displacement damage, but fortunately most are not. Researchers compare the responses of the new technologies with those of the mainstream technologies of PV HgCdTe and IBC Si:As. One important reason for this comparison is to note where some of the newer technologies have the potential to provide significantly improved radiation hardness compared with that of the mainstream technologies, and thus to provide greater motivation for the pursuit of these technologies.

  11. Improved performance lead iodide nuclear radiation detectors

    Microsoft Academic Search

    V. Deich; M. Roth

    1996-01-01

    Melt-grown lead iodide single crystals with an improved transport of positive charge carriers (holes) have been developed. It is shown that an energy resolution of about 3% can be obtained for gamma-radiation at 60 keV (241Am isotope source). Improvement of the spectrometric performance of lead iodide detectors at lower gamma-ray energies has been achieved as well due to better purification

  12. Boron phosphide on silicon for radiation detectors

    Microsoft Academic Search

    J. C. Lund; F. Olschner; K. S. Shah; F. Ahmed

    1989-01-01

    We report on radiation detectors fabricated from boron phosphide (BP) layers. These devices were fabricated by growing 1 to 10 μm thick layers of BP by chemical vapor deposition (CVD) on (100) oriented n-type silicon substrates. Ohmic contacts were applied to the Si (Au--Sb). Schottky barrier contacts (also Au--Sb) were applied to the BP layer. The devices were tested as

  13. Thermal and nonequilibrium responses of superconductors for radiation detectors

    Microsoft Academic Search

    Z. M. Zhang; A. Frenkel

    1994-01-01

    This work summarizes the progress in the study of the superconductor response to optical radiation and in the development of infrared detectors. The recent advances in the design of high-Tc superconducting radiation detectors using silicon microfabrication technology are emphasized. Thermal and optical properties important for the detector performance are discussed. The mechanism of the nonequilibrium optical response and its potential

  14. GaN Radiation Detectors for Particle Physics and

    E-print Network

    Glasgow, University of

    and neutrons led to a dramatic reduction in the CCE of the GaN detectors. For II #12;example, the CCE of oneGaN Radiation Detectors for Particle Physics and Synchrotron Applications James Paul Grant and monitoring applications. Gallium nitride (GaN) was investigated as a radiation hard particle detector

  15. Radiation damage measurements in room-temperature semiconductor radiation detectors

    Microsoft Academic Search

    Larry A. Franks; Bruce A. Brunett; Richard W. Olsen; David S. Walsh; Gyögy Vizkelethy; Jacob I. Trombka; Barney L. Doyle; Ralph B. James

    1999-01-01

    The literature of radiation damage measurements on cadmium zinc telluride (CZT), cadmium telluride (CT), and mercuric iodide (HgI2) is reviewed and in the case of CZT supplemented by new alpha particle data. CZT strip detectors exposed to intermediate energy (1.3MeV) proton fluences exhibit increased interstrip leakage after 1010 p\\/cm2 and significant bulk leakage after 1012 p\\/cm2. CZT exposed to 200MeV

  16. A new transition radiation detector for cosmic ray nuclei

    NASA Technical Reports Server (NTRS)

    Lheureux, J.; Meyer, P.; Muller, D.; Swordy, S.

    1981-01-01

    Test measurements on materials for transition radiation detectors at a low Lorentz factor are reported. The materials will be based on board Spacelab-2 for determining the composition and energy spectra of nuclear cosmic rays in the 1 TeV/nucleon range. The transition radiation detectors consist of a sandwich of radiator-photon detector combinations. The radiators emit X-rays and are composed of polyolefin fibers used with Xe filled multiwired proportional chamber (MWPC) detectors capable of detecting particle Lorentz factors of several hundred. The sizing of the detectors is outlined, noting the requirement of a thickness which provides a maximum ratio of transition radiation to total signal in the chambers. The fiber radiator-MWPC responses were tested at Fermilab and in an electron cyclotron. An increase in transition radiation detection was found as a square power law of Z, and the use of six radiator-MWPC on board the Spacelab-2 is outlined.

  17. A threshold type Cerenkov radiation detector

    E-print Network

    Winningham, John David

    1965-01-01

    . W , i CHAPTER II IHE CERENROV DETECTOR AND THE ASSOCIATED ELECTRONICS A. Th" Natal Enclosure The essential features of the tank are shown in Fig. I. 4, The tank is constructed of I/8-inch hard aluminum plates which are heli. -arc welded... together. Cylindrical tubes are welded in the centers of two sides in order that the photomultiplier tubes can be installed in direct contact with the liquid radiator inside. 0-rings are placed in two grooves inside each of the cylinders in order...

  18. IMPROVEMENTS IN OR RELATING TO NUCLEAR RADIATION DETECTOR SHIELDING

    Microsoft Academic Search

    1962-01-01

    A radiation detection unit is provided with castle shielding consisting ; of lid, sleeve, radiation detector tube mounting, and base sections. The ; positions of the radiation detector tube mounting and sleeve sections may be ; interchanged relative to the base. (R.J.S.)

  19. Position Sensitive Radiation Detector Integrated with an FPGA for Radiation Tolerant Computing

    E-print Network

    LaMeres, Brock J.

    Position Sensitive Radiation Detector Integrated with an FPGA for Radiation Tolerant Computing radiation sensor was modeled, developed and fabricated then interfaced with a field programmable gate array (FPGA) to create a radiation hardened computing platform. The system exploits environmental information

  20. Physics with the ALICE Transition Radiation Detector

    E-print Network

    Yvonne Pachmayer for the ALICE Collaboration

    2011-12-09

    The ALICE Transition Radiation Detector (TRD) significantly enlarges the scope of physics observables studied in ALICE, because it allows due to its electron identification capability to measure open heavy-flavour production and quarkonium states, which are essential probes to characterize the Quark-Gluon-Plasma created in nucleus-nucleus collisions at LHC. In addition the TRD enables to enhance rare probes due to its trigger contributions. We report on the first results of the electron identification capability of the ALICE Transition Radiation Detector (TRD) in pp collisions at $\\sqrt{s}$ = 7 TeV using a one-dimensional likelihood method on integrated charge measured in each TRD chamber. The analysis of heavy flavour production in pp collisions at $\\sqrt{s}$ = 7 TeV with this particle identification method, which extends the $p_{t}$ range of the existing measurement from $p_{t}$ = 4 GeV/c to 10 GeV/c and reduces the systematic uncertainty due to particle identification, is presented. The performance of the application of the TRD electron identification in the context of J/\\psi measurements in Pb-Pb collisions is also shown.

  1. Radiation detector system having heat pipe based cooling

    DOEpatents

    Iwanczyk, Jan S.; Saveliev, Valeri D.; Barkan, Shaul

    2006-10-31

    A radiation detector system having a heat pipe based cooling. The radiation detector system includes a radiation detector thermally coupled to a thermo electric cooler (TEC). The TEC cools down the radiation detector, whereby heat is generated by the TEC. A heat removal device dissipates the heat generated by the TEC to surrounding environment. A heat pipe has a first end thermally coupled to the TEC to receive the heat generated by the TEC, and a second end thermally coupled to the heat removal device. The heat pipe transfers the heat generated by the TEC from the first end to the second end to be removed by the heat removal device.

  2. Miniature scintillating detector for small field radiation therapy D. Letourneaua)

    E-print Network

    Pouliot, Jean

    Miniature scintillating detector for small field radiation therapy D. Le´tourneaua) Centre curves, profiles, and dose rate of treatment beams are difficult to obtain with conventional detectors because of loss of lateral elec- tronic equilibrium and volume averaging. A scintillating detector

  3. Novel radiation hard microfabricated scintillation detectors with high spatial resolution

    E-print Network

    Dalang, Robert C.

    Novel radiation hard microfabricated scintillation detectors with high spatial resolution A, Switzerland a r t i c l e i n f o Available online 4 July 2009 Keywords: Scintillation detectors Microfabrication Microfluidics a b s t r a c t A novel liquid scintillation detector with high spatial resolution

  4. Detection of Nuclear Radiations; DETECTORES DE RADIACIONES NUCLEARES

    Microsoft Academic Search

    Sanz

    1959-01-01

    The lectures given on radiation detection instruments are summarized. ; The detectors discussed are ionization chambers, proportional counters, Geiger ; counters, scintillation detectors, and neutron detectors. The characteristics ; which must be considered in the design of associated electronic equipment are ; emphasized. (J.S.R.);

  5. Space Radiation Detector with Spherical Geometry

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D. (Inventor); Fralick, Gustave C. (Inventor); Wrbanek, Susan Y. (Inventor)

    2011-01-01

    A particle detector is provided, the particle detector including a spherical Cherenkov detector, and at least one pair of detector stacks. In an embodiment of the invention, the Cherenkov detector includes a sphere of ultraviolet transparent material, coated by an ultraviolet reflecting material that has at least one open port. The Cherenkov detector further includes at least one photodetector configured to detect ultraviolet light emitted from a particle within the sphere. In an embodiment of the invention, each detector stack includes one or more detectors configured to detect a particle traversing the sphere.

  6. Space Radiation Detector with Spherical Geometry

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D. (Inventor); Fralick, Gustave C. (Inventor); Wrbanek, Susan Y. (Inventor)

    2012-01-01

    A particle detector is provided, the particle detector including a spherical Cherenkov detector, and at least one pair of detector stacks. In an embodiment of the invention, the Cherenkov detector includes a sphere of ultraviolet transparent material, coated by an ultraviolet reflecting material that has at least one open port. The Cherenkov detector further includes at least one photodetector configured to detect ultraviolet light emitted from a particle within the sphere. In an embodiment of the invention, each detector stack includes one or more detectors configured to detect a particle traversing the sphere.

  7. Synthetic diamonds as ionisation chamber radiation detectors in biological environments

    Microsoft Academic Search

    R. J. Keddy; T. L. Nam

    1987-01-01

    Synthetic diamonds with nitrogen concentrations higher than previously reported in the literature are found to operate very effectively as alpha-particle detectors, as well as detectors for gamma radiation, when operated as ionisation chambers. Certain of the specimens exhibited extensive linear response characteristics when subjected to either alpha particles or gamma radiation of various dose rates. For alpha particles, the response

  8. Pyroelectric detector development for the Radiation Measurement system

    NASA Technical Reports Server (NTRS)

    Hubbard, G. S.; Mcmurray, Robert E., Jr.; Hanel, R. P.; Dominguez, D. E.; Valero, F. P. J.; Baumann, Hilary; Hansen, W. L.; Haller, E. E.

    1993-01-01

    A new class of high detectivity pyroelectric detectors developed for optimization of the radiation measurement system within the framework of the Atmospheric Radiation Measurement program is described. These devices are intended to provide detectivities of up to about 10 exp 11 cm Hz exp 0.5/W with cooling to about 100 K required for the detector focal plane.

  9. Real-time self-networking radiation detector apparatus

    DOEpatents

    Kaplan, Edward (Stony Brook, NY); Lemley, James (Miller Place, NY); Tsang, Thomas Y. (Holbrook, NY); Milian, Laurence W. (East Patchogue, NY)

    2007-06-12

    The present invention is for a radiation detector apparatus for detecting radiation sources present in cargo shipments. The invention includes the features of integrating a bubble detector sensitive to neutrons and a GPS system into a miniaturized package that can wirelessly signal the presence of radioactive material in shipping containers. The bubble density would be read out if such indicated a harmful source.

  10. Progress in the Development of Plasma Panel Radiation Detectors

    E-print Network

    Robert Ball; James R. Beene; Yan Benhammou; Meny Ben Moshe; J. Wehrley Chapman; Tiesheng Dai; Erez Etzion; Peter S. Friedman; Daniel S. Levin; Yiftah Silver; Guy Sherman; Robert L. Varner Jr.; Curtis Weaverdyck; Steve White; J. Yu; Bing Zhou

    2010-12-30

    Plasma Display Panels (PDP), the underlying engine of panel plasma television displays, are being investigated for their utility as radiation detectors called Plasma Panel Sensors (PPS). The PPS a novel variant of a micropattern radiation detector, is intended to be a fast, high resolution detector comprised of an array of plasma discharge cells operating in a hermetically sealed gas mixture. We report on the PPS development effort, including recent laboratory measurements.

  11. Wire chamber radiation detector with discharge control

    DOEpatents

    Perez-Mendez, Victor (Berkeley, CA); Mulera, Terrence A. (Berkeley, CA)

    1984-01-01

    A wire chamber radiation detector (11) has spaced apart parallel electrodes (16) and grids (17, 18, 19) defining an ignition region (21) in which charged particles (12) or other ionizing radiations initiate brief localized avalanche discharges (93) and defining an adjacent memory region (22) in which sustained glow discharges (94) are initiated by the primary discharges (93). Conductors (29, 32) of the grids (18, 19) at each side of the memory section (22) extend in orthogonal directions enabling readout of the X-Y coordinates of locations at which charged particles (12) were detected by sequentially transmitting pulses to the conductors (29) of one grid (18) while detecting transmissions of the pulses to the orthogonal conductors (36) of the other grid (19) through glow discharges (94). One of the grids (19) bounding the memory region (22) is defined by an array of conductive elements (32) each of which is connected to the associated readout conductor (36) through a separate resistance (37). The wire chamber (11) avoids ambiguities and imprecisions in the readout of coordinates when large numbers of simultaneous or near simultaneous charged particles (12) have been detected. Down time between detection periods and the generation of radio frequency noise are also reduced.

  12. Radiation damage studies for the D0 silicon detector

    SciTech Connect

    Lehner, F.; /Zurich U.; ,

    2004-01-01

    We report on irradiation studies performed on spare production silicon detector modules for the current D0 silicon detector. The lifetime expectations due to radiation damage effects of the existing silicon detector are reviewed. A new upgrade project was started with the goal of a complete replacement of the existing silicon detector. In that context, several investigations on the radiation hardness of new prototype silicon microstrip detectors were carried out. The irradiation on different detector types was performed with 10 MeV protons up to fluences of 10{sup 14} p/cm{sup 2} at the J.R. Mcdonald Laboratory at Kansas State University. The flux calibration was carefully checked using different normalization techniques. As a result, we observe roughly 40-50% less radiation damage in silicon for 10 MeV p exposure than it is expected by the predicted NIEL scaling.

  13. Radiation damage studies for the DØ silicon detector

    NASA Astrophysics Data System (ADS)

    Lehner, Frank; DØ Collaboration

    2004-09-01

    We report on irradiation studies performed on spare production silicon detector modules for the current D Ø silicon detector. The lifetime expectations due to radiation damage effects of the existing silicon detector are reviewed. A new upgrade project was started with the goal of a complete replacement of the existing silicon detector. In that context, several investigations on the radiation hardness of new prototype silicon microstrip detectors were carried out. The irradiation on different detector types was performed with 10 MeV protons up to fluences of 10 14 p/ cm2 at the J.R. Mcdonald Laboratory at Kansas State University. The flux calibration was carefully checked using different normalisation techniques. As a result, we observe roughly 40-50% less radiation damage in silicon for 10 MeV p exposure than it is expected by the predicted NIEL scaling.

  14. Radiation Effect On Gas Electron Multiplier Detector Performance

    NASA Astrophysics Data System (ADS)

    Park, Kwang June; Baldeloma, Edwin; Park, Seongtae; White, Andrew P.; Yu, Jaehoon

    2011-06-01

    Gas Electron Multiplier (GEM) detector is a gas device with high gain and high efficiency. These detectors use chemically perforated 65 ?m thick copper clad Kapton polyimide foils. Given its potential for detecting X-rays and other radiations, GEM detectors may be used in an environment with high radioactivity. The Kapton foils manufacturer, Du Pont Inc., claims that the foils are radioactive resistant. To verify whether the GEM detector performance is affected by the exposure to radiation, several GEM foils were irradiated to a 60Co source at the gamma-ray irradiation facility at Sterigenics, Tustin, CA. Four sets of GEM foils were exposed to the level of 10 kGy, 100 kGy, 1,000 kGy and 10,000 kGy. The output signal from the GEM detectors with irradiated GEM foils were measured and compared to the detector with no irradiation. We observed that the shapes of the peaks from 5.9 KeV 55Fe X-ray were distorted and that the detector gain increased compared to that of the un-irradiated detector. In particular, the detector with 10,000 kGy irradiation appeared to have the biggest peak distortion and increased gain. It was also found from that additional electrons from radiation-induced free radicals in the Kapton film contribute to output signal of the irradiated GEM detectors. Further studies are needed to explain the mechanism of these detector performance changes.

  15. Flame detector operable in presence of proton radiation

    NASA Technical Reports Server (NTRS)

    Walker, D. J.; Turnage, J. E.; Linford, R. M. F.; Cornish, S. D. (inventors)

    1974-01-01

    A detector of ultraviolet radiation for operation in a space vehicle which orbits through high intensity radiation areas is described. Two identical ultraviolet sensor tubes are mounted within a shield which limits to acceptable levels the amount of proton radiation reaching the sensor tubes. The shield has an opening which permits ultraviolet radiation to reach one of the sensing tubes. The shield keeps ultraviolet radiation from reaching the other sensor tube, designated the reference tube. The circuitry of the detector subtracts the output of the reference tube from the output of the sensing tube, and any portion of the output of the sensing tube which is due to proton radiation is offset by the output of the reference tube. A delay circuit in the detector prevents false alarms by keeping statistical variations in the proton radiation sensed by the two sensor tubes from developing an output signal.

  16. Large dynamic range radiation detector and methods thereof

    DOEpatents

    Marrs, Roscoe E. (Livermore, CA); Madden, Norman W. (Sparks, NV)

    2012-02-14

    According to one embodiment, a radiation detector comprises a scintillator and a photodiode optically coupled to the scintillator. The radiation detector also includes a bias voltage source electrically coupled to the photodiode, a first detector operatively electrically coupled to the photodiode for generating a signal indicative of a level of a charge at an output of the photodiode, and a second detector operatively electrically coupled to the bias voltage source for generating a signal indicative of an amount of current flowing through the photodiode.

  17. A CMOS integrated infrared radiation detector for flame monitoring

    Microsoft Academic Search

    P. Bendiscioli; F. Francesconi; P. Malcovati; F. Maloberti; M. Poletti; R. Valacca

    1998-01-01

    This paper presents an integrated infrared radiation detector for flame monitoring applications, fabricated in CMOS technology. The system discriminates the radiation of the flickering flame in an oil burner from the steady background radiation generated by the furnace by considering only the harmonic components of the infrared signal in the band from 50 Hz to 250 Hz. In order to

  18. A Xylophone Detector of Gravitational Radiation

    NASA Technical Reports Server (NTRS)

    Tinto, Massimo

    1997-01-01

    We discuss spacecraft Doppler tracking searches for gravitational waves in which Doppler data recorded on the ground are linearly combined with Doppler measurements made on board a spacecraft. By using the four-link radio system first proposed by Vessot and Levine, we describe a new method for removing from the combined data the frequency fluctuations due to the Earth troposphere, ionosphere, and mechanical vibrations of the antenna on the ground. This technique provides also a way for reducing by several orders of magnitude, at selected Fourier components, the frequency fluctuations due to other noise sources, such as the clock on board the spacecraft or the antenna and buffeting of the probe by nongravitational forces. In this respect spacecraft Doppler tracking can be regarded as a xylophone detector of gravitational radiation. In the assumption of calibrating the frequency fluctuations induced by the interplanetary plasma, a strain sensitivity equal to 4.7 x 10(exp -18) at 10(exp -3) Hz is estimated. This experimental technique could be extended to other tests of the theory of relativity, and to radio science experiments that rely on high-precision Doppler measurements.

  19. Heat Transfer Issues in Thin-Film Thermal Radiation Detectors

    NASA Technical Reports Server (NTRS)

    Barry, Mamadou Y.

    1999-01-01

    The Thermal Radiation Group at Virginia Polytechnic Institute and State University has been working closely with scientists and engineers at NASA's Langley Research Center to develop accurate analytical and numerical models suitable for designing next generation thin-film thermal radiation detectors for earth radiation budget measurement applications. The current study provides an analytical model of the notional thermal radiation detector that takes into account thermal transport phenomena, such as the contact resistance between the layers of the detector, and is suitable for use in parameter estimation. It was found that the responsivity of the detector can increase significantly due to the presence of contact resistance between the layers of the detector. Also presented is the effect of doping the thermal impedance layer of the detector with conducting particles in order to electrically link the two junctions of the detector. It was found that the responsivity and the time response of the doped detector decrease significantly in this case. The corresponding decrease of the electrical resistance of the doped thermal impedance layer is not sufficient to significantly improve the electrical performance of the detector. Finally, the "roughness effect" is shown to be unable to explain the decrease in the thermal conductivity often reported for thin-film layers.

  20. Thermal treatment of CdTe surfaces for radiation detectors

    Microsoft Academic Search

    T. Ozaki; Y. Iwase; H. Takamura; M. Ohmori

    1996-01-01

    In order to decrease the leakage current of In\\/CdTe\\/Au radiation detectors, thermal treatment of the CdTe wafers was introduced into the detector fabrication process. Detectors were fabricated from Cl-doped THM-grown high-resistivity wafers. The thermal treatment was carried out in a vacuum evaporator at 200–300°C before deposition of the In electrode. An Au electrode was formed by electroless plating. The thermal

  1. Effects of ionizing radiation on cryogenic infrared detectors

    NASA Technical Reports Server (NTRS)

    Moseley, S. H.; Silverberg, R. F.; Lakew, B.

    1989-01-01

    The Diffuse Infrared Background Experiment (DIRBE) is one of three experiments to be carried aboard the Cosmic Background Explorer (COBE) satellite scheduled to be launched by NASA on a Delta rocket in 1989. The DIRBE is a cryogenic absolute photometer operating in a liquid helium dewar at 1.5 K. Photometric stability is a principal requirement for achieving the scientific objectives of this experiment. The Infrared Astronomy Satellite (IRAS), launched in 1983, which used detectors similar to those in DIRBE, revealed substantial changes in detector responsivity following exposure to ionizing radiation encountered on passage through the South Atlantic Anomaly (SAA). Since the COBE will use the same 900 Km sun-synchronous orbit as IRAS, ionizing radiation-induced performance changes in the detectors were a major concern. Here, ionizing radiation tests carried out on all the DIRBE photodetectors are reported. Responsivity changes following exposure to gamma rays, protons, and alpha particle are discussed. The detector performance was monitored following a simulated entire mission life dose. In addition, the response of the detectors to individual particle interactions was measured. The InSb photovoltaic detectors and the Blocked Impurity Band (BIB) detectors revealed no significant change in responsivity following radiation exposure. The Ge:Ga detectors show large effects which were greatly reduced by proper thermal annealing.

  2. The role of contacts in semiconductor gamma radiation detectors

    Microsoft Academic Search

    Uri Lachish

    1998-01-01

    It is proposed that the operation of semiconductor gamma radiation detectors, equipped with ohmic contacts, which allow free electron flow between the contacts and bulk material, will not be sensitive to low hole mobility, hole collection efficiency, or hole trapping. Such fast-operating detectors may be readily integrated into monolithic arrays. The detection mechanism and various material aspects are discussed and

  3. Improved Infrared Response Measurements in Semiconductor Nuclear Radiation Detectors

    Microsoft Academic Search

    A. H. Sher; W. J. Keery; H. E. Dyson

    1972-01-01

    An infrared response technique has been developed wnich has been shown to yield more detailed spectra than previous techniques and which can be used to identify more specifically energy levels arising from unwanted impurities and defects in semiconductor diodes used as nuclear radiation detectors. The presence of known impurities in germanium detectors, both lithium-compensated and high purity (uncompensated), has been

  4. Analysis of semiconductor nuclear radiation detectors with arbitrary electrode geometries

    Microsoft Academic Search

    J. F. Butler; C. L. Lingren

    1998-01-01

    This paper develops a theoretical framework and sets of differential and integral equations for analyzing the operating characteristics of semiconductor nuclear radiation detectors with arbitrary electrode geometries. Results provide a basis for conceptualization and numerical calculations and are relevant to recent substantial improvements in detector performance achieved through various single-carrier charge collection schemes based on special electrode configurations. During the

  5. High purity liquid phase epitaxial gallium arsenide nuclear radiation detector

    Microsoft Academic Search

    Dimitri Alexiev; K. S. A. Butcher

    1992-01-01

    Surface barrier radiation detector made from high purity liquid phase epitaxial gallium arsenide wafers have been operated as X- and gamma-ray detectors at various operating temperatures. Low energy isotopes are resolved including 241Am at 40°C and the higher gamma energies of 235U at -80°C.

  6. Modelling the effects of electrical traps in radiation detectors

    Microsoft Academic Search

    K. Kandiah

    1996-01-01

    We describe a method, for deriving the shape and position of the photopeak as functions of the electrical parameters of the traps, from first principles, without using empirical factors, but assuming a knowledge of detector geometry, bias, temperature and radiation conditions. The paper deals only with the charge loss in the detector for photo electric events with the emphasis on

  7. Bismuth tri-iodide crystal for nuclear radiation detectors

    Microsoft Academic Search

    Manabu Matsumoto; Keitaro Hitomi; Tadayoshi Shoji; Yukio Hiratate

    2002-01-01

    Bismuth tri-iodide (BiI3) is an attractive material for room temperature radiation detectors because of its wide bandgap energy and high photon stopping power. In this paper, BiI3 crystals have been grown by the vertical Bridgman technique using commercially available powder. The grown crystals have been characterized in terms of their structural properties and stoichiometry. Room temperature radiation detectors have been

  8. Bismuth iodide (III) crystals for nuclear radiation detectors

    Microsoft Academic Search

    M. Matsumoto; K. Hitomi; T. Shoji; Y. Hiratate

    2001-01-01

    Bismuth tri-iodide (BiI3) is an attractive material for room temperature radiation detectors because of its wide bandgap energy and high photon stopping power. In this study, BiI3 crystals have been grown by the vertical Bridgman technique using commercially available powder. The grown crystals have been characterized in terms of their structural properties and stoichiometry. Room temperature radiation detectors have been

  9. Author's personal copy Monte Carlo methods for design and analysis of radiation detectors

    E-print Network

    Shultis, J. Kenneth

    Author's personal copy Monte Carlo methods for design and analysis of radiation detectors William L Radiation detectors Inverse problems Detector design a b s t r a c t An overview of Monte Carlo as a practical method for designing and analyzing radiation detectors is provided. The emphasis is on detectors

  10. Recent advances in compound semiconductor radiation detectors

    Microsoft Academic Search

    Paul J Sellin

    2003-01-01

    Recent developments in compound semiconductor detectors are reviewed, highlighting the latest spectroscopic performance from devices fabricated from a range of wide bandgap materials. Cadmium zinc telluride and cadmium telluride continue to dominate the field, with a range of prototype imaging detectors under development, principally for nuclear medicine and X-ray astronomy applications. Improvements in material quality and supply plus metal–semiconductor contact

  11. The pin detector - A simple, robust, cheap and effective nuclear radiation detector

    Microsoft Academic Search

    J. E. Bateman

    1985-01-01

    The development of a series of radiation detectors based on the point anode is reported. Using readily available preformed pins from a variety of electrical connectors as the anodes, a family of devices has been created with useful properties as X-ray detectors, radiation monitors and internal beta counters. A wide variety of gas fillings can be used, argon\\/CH4 premix being

  12. Studies of exotic nuclei with advanced radiation detectors

    NASA Astrophysics Data System (ADS)

    Podolyák, Zsolt

    2014-02-01

    Contemporary key nuclear physics questions are introduced. The role of radiation detection in the study of exotic nuclei is illustrated with examples related to NuSTAR at the FAIR facility. The discussed detection systems include: Si-tracker for light charged particle detection, the AGATA gamma-ray tracking detector, diamond detectors for heavy ion measurements, the AIDA implantation and decay detector, and the LaBr3(Ce) fast-timing array. Due to technology transfer, applications related to radiation physics are expected to benefit from these developments.

  13. The Transition Radiation Detector for ALICE at LHC

    E-print Network

    M. J. Kweon; for the ALICE TRD Collaboration

    2009-09-25

    The Transition Radiation Detector (TRD) for the ALICE experiment at the Large Hadron Collider (LHC) identifies electrons in p+p and in the challenging high multiplicity environment of heavy-ion collisions and provides fast online tracking for the ALICE Level1 trigger. The TRD is designed to have excellent position resolution and pion rejection capability. Presently, six of the 18 TRD supermodules are installed in the ALICE central barrel. In 2008, four supermodules were installed and commissioning of the detector using cosmic ray tracks was successfully performed. We briefly describe the design of the detector and report on the performance and current understanding of the detector based on these data.

  14. Proton-induced radiation damage in germanium detectors

    NASA Technical Reports Server (NTRS)

    Brueckner, J.; Koerfer, M.; Waenke, H.; Schroeder, A. N. F.; Filges, D.; Dragovitsch, P.; Englert, P. A. J.; Starr, R.; Trombka, J. I.

    1991-01-01

    High-purity germanium (HPGe) detectors will be used in future space missions for gamma-ray measurements and will be subject to interactions with energetic particles. To simulate this process, several large-volume n-type HPGe detectors were incrementally exposed to a particle fluence of up to 10 to the 8th protons/sq cm (proton energy: 1.5 GeV) at different operating temperatures (90 to 120 K) to induce radiation damage. Basic scientific and engineering data on detector performance were collected. During the incremental irradiation, the peak shape produced by the detectors showed a significant change from a Gaussian shape to a broad complex structure. After the irradiation, all detectors were thoroughly characterized by measuring many parameters. To remove the accumulated radiation damage, the detectors were stepwise-annealed at temperatures below 110 C, while kept in their specially designed cryostats. This study shows that n-type HPGe detectors can be used in charged-particle environments as high-energy resolution devices until a certain level of radiation damage is accumulated and that the damage can be removed at moderate annealing temperatures and the detector returned to operating condition.

  15. A hybrid radiation detector for simultaneous spatial and temporal dosimetry.

    PubMed

    Poole, C; Trapp, J V; Kenny, J; Kairn, T; Williams, K; Taylor, M; Franich, R; Langton, C M

    2011-09-01

    In this feasibility study an organic plastic scintillator is calibrated against ionisation chamber measurements and then embedded in a polymer gel dosimeter to obtain a quasi-4D radiation detector. This hybrid dosimeter was irradiated with megavoltage x-rays from a linear accelerator, with temporal measurements of the dose rate being acquired by the scintillator and spatial measurements acquired with the gel dosimeter. The detectors employed in this study are radiologically equivalent; and we show that neither detector perturbs the intensity of the radiation field of the other. By employing these detectors in concert, spatial and temporal variations in the radiation intensity can now be detected and gel dosimeters can be calibrated for absolute dose from a single irradiation. PMID:21678102

  16. Development of position sensitive radiation detectors using gas electron multipliers.

    PubMed

    Park, Seongtae; Hahn, Chang Hie

    2009-01-01

    Gas electron multipliers (GEM) were introduced to develop a radiation detector which is applicable to medical imaging or luggage inspection systems at the airport or harbor. Two GEM foils were used in the amplifier, and an Ar/CO(2) mixed gas was inserted into the chamber at a mixing ratio of Ar:CO(2)=80:20. A two-dimensional X-ray image was taken with a 64-channel GEM detector from an Fe-55 radiation source. We also constructed a 256-channel GEM detector in which 4 charge sensitive preamplifiers were used in a daisy chain. With linear array type readout electrodes, we were able to realize a position sensitive radiation detector. PMID:19282195

  17. Polarization Phenomena in CdTe Nuclear Radiation Detectors

    Microsoft Academic Search

    H. L. Malm; M. Martini

    1974-01-01

    Nuclear radiation detectors made from high resistivity chlorine doped cadmium telluride grown by the travelling heater method were evaluated. Short term performance for ¿, ??, and ¿ radiations was good but the long term performance (>1 min) was degraded by a decrease in the full energy pulse height and ¿-ray efficiency with time after the bias voltage was applied. A

  18. Design of a transition radiation detector for cosmic rays

    NASA Technical Reports Server (NTRS)

    Hartmann, G.; Mueller, D.; Prince, T.

    1975-01-01

    Transition radiation detectors consisting of sandwiches of plastic foam radiators and multiwire proportional chambers can be used to identify cosmic ray particles with energies gamma ? E/mc-squared is greater than 10 to the 3rd and to measure their energy in the region gamma is roughly equal to 10 to the 3rd

  19. Using cumulants and spectra to model nuclear radiation detectors

    Microsoft Academic Search

    Eduardo Winston Pontes; Ademar Ferreira

    2006-01-01

    A general mathematical methodology is presented to model a nuclear radiation detector. This is accomplished by using a proposed generalization of Campbell's theorem, which employs nth-order cumulants and spectra analysis and a vector of random parameters to describe the current pulses. This allows a more elaborate, higher order statistical characterization of the radiation detection process, as compared to the usual

  20. Integrated nuclear radiation detector and monitor

    Microsoft Academic Search

    B. L. Biehl; S. I. Lieberman

    1982-01-01

    A battery powered device which can continuously monitor and detect nuclear radiation utilizing fully integrated circuitry and which is provided with an alarm which alerts persons when the radiation level exceeds a predetermined threshold.

  1. On the Cancellation Mechanism of Radiation from the Unruh detector

    E-print Network

    S. Iso; K. Yamamoto; S. Zhang

    2013-01-31

    A uniformly accelerated detector (Unruh detector) in the Minkowski vacuum is excited as if it is exposed to the thermal bath with temperature proportional to its acceleration. In the inertial frame, since both of an excitation and a deexcitation of the detector are accompanied by emission of radiation into the Minkowski vacuum, one may suspect that the Unruh detector emits radiation like the Larmor radiation from an accelerated charged particle. However, it is known that the radiation is miraculously cancelled by a quantum interference effect. In this paper, we investigate under what condition the radiation cancels out. We first show that the cancellation occurs if the Green function satisfies a relation similar to the Kubo-Martin-Schwinger (KMS) condition. We then study two examples, Unruh detectors in the 3+1 dimensional Minkowski spacetime and in the de Sitter spacetime. In both cases, the relation holds only in a restricted region of the spacetime, but the radiation is cancelled in the whole spacetime. Hence the KMS-like relation is necessary but not sufficient for the cancellation to occur.

  2. Nuclear radiation-warning detector that measures impedance

    DOEpatents

    Savignac, Noel Felix; Gomez, Leo S; Yelton, William Graham; Robinson, Alex; Limmer, Steven

    2013-06-04

    This invention is a nuclear radiation-warning detector that measures impedance of silver-silver halide on an interdigitated electrode to detect light or radiation comprised of alpha particles, beta particles, gamma rays, X rays, and/or neutrons. The detector is comprised of an interdigitated electrode covered by a layer of silver halide. After exposure to alpha particles, beta particles, X rays, gamma rays, neutron radiation, or light, the silver halide is reduced to silver in the presence of a reducing solution. The change from the high electrical resistance (impedance) of silver halide to the low resistance of silver provides the radiation warning that detected radiation levels exceed a predetermined radiation dose threshold.

  3. The charged particle response of silicon carbide semiconductor radiation detectors

    Microsoft Academic Search

    Frank H. Ruddy; Abdul R. Dulloo; John G. Seidel; John W. Palmour; Ranbir Singh

    2003-01-01

    Silicon carbide (SiC) radiation detectors are being developed for high-temperature applications in harsh radiation environments. The wide band gap of SiC (3.25eV) compared to conventional semiconductors such as silicon (1.1eV) and the relatively high-radiation resistance of SiC make it a semiconductor, that is highly suited for such applications. In this paper, we report on charged particle response measurements with larger-sized

  4. Recent progress in the development of transition radiation detectors

    NASA Technical Reports Server (NTRS)

    Cherry, M. L.; Hartmann, G.; Prince, T.; Mueller, D.

    1978-01-01

    Transition-radiation detectors have been used in several recent cosmic-ray experiments for particle identification at energies E/mc-squared of at least about 1000. In order to optimize the design of such detectors and to use them for energy measurements over a broad energy range, it is necessary to study the details of the transition-radiation process. Experimental results are presented which test the theoretical predictions more precisely and at higher energies than in previous experiments. The dependence of the interference pattern in the frequency spectrum on the radiator dimensions is studied, and the total transition-radiation yield generated by electrons in various radiators is measured over a very wide energy range, from 5 to 300 GeV. The significance of the individual experimental parameters in the design of transition radiation detectors is reviewed, and the characteristics of transition-radiation detectors capable of measuring particle energies over the range E/mc-squared from about 300 to 100,000 are discussed.

  5. Extended Defects in Cdznte Radiation Detectors

    SciTech Connect

    Bolotnikov, A.; Babalola, S; Camarda, G; Chen, H; Awadalla, S; Cui, Y; Egarievwe, S; Fochuk, P; Hawrami, R; et. al.

    2009-01-01

    Large-volume CdZnTe (CZT) single crystals with electron lifetime exceeding 10 mus have recently become commercially available. This opened the opportunity for making room temperature CZT gamma-ray detectors with extended thicknesses and larger effective areas. However, the extended defects that are present even in the highest-quality material remain a major drawback which affects the availability and cost of large CZT detectors. In contrast to the point defects that control electron lifetime and whose effects on the charge collection can be electronically corrected, the extended defects introduce significant fluctuations in the collected charge, which increase with a crystal's thickness. The extended defects limit the uniformity in the electrons' drift distance in CZT crystals, above which electron trapping cannot effectively be corrected. In this paper, we illustrate the roles of the extended defects in CZT detectors with different geometries. We emphasize that the crystallinity of commercial CZT materials remains a major obstacle on the path to developing thick, large-volume CZT detectors for gamma-ray imaging and spectroscopy.

  6. LALP-07-091 Fall 2007 Development of improved radiation detector materials

    E-print Network

    LALP-07-091 Fall 2007 Development of improved radiation detector materials Tailored processing new radiation detectors. The per- formance of these detectors can be significantly enhanced if the materials Laboratory have unique expertise to provide this requisite optimization of radiation detector materials

  7. Charge transport properties of CdMnTe radiation detectors

    Microsoft Academic Search

    Kim K; R. Rafiel; M. Boardman; I. Reinhard; A. Sarbutt; G. Watt; C. Watt; S. Uxa; D. A. Prokopovich; E. Belas; A. E. Bolotnikov; R. B. James

    2012-01-01

    Growth, fabrication and characterization of indium-doped cadmium manganese telluride (CdMnTe)radiation detectors have been described. Alpha-particle spectroscopy measurements and time resolved current transient measurements have yielded an average charge collection efficiency approaching 100 %. Spatially resolved charge collection efficiency maps have been produced for a range of detector bias voltages. Inhomogeneities in the charge transport of the CdMnTe crystals have been

  8. Phonon-mediated detectors of radiation: state of the art

    Microsoft Academic Search

    Andrea Giuliani

    2001-01-01

    Basic operation principles of phonon-mediated low-temperature detectors of radiation are briefly reviewed. Physical properties required for the energy absorbers and for the phonon sensors of the detectors are introduced and discussed. Semiconductor thermistors, superconductive tunnel junctions and transition edge films as phonon sensors are presented and critically compared. State-of-art of single quantum detection with these devices is reported. Particular emphasis

  9. High resolution room temperature ionization chamber xenon gamma radiation detector

    Microsoft Academic Search

    Gary Tepper; Jon Losee

    1995-01-01

    A unique thin walled dual-type gridded ionization chamber gamma radiation detector using ultra pure Xe gas as the detection medium is described. The detector was operated at room temperature and the energy spectra of 60Co, 137Cs, 22Na and 133Ba were obtained. An energy resolution of (16 keV) 2.4% FWHM was determined for the 662 keV 137Cs gamma peak which is

  10. Method for manufacturing nuclear radiation detector with deep diffused junction

    Microsoft Academic Search

    Hall

    1977-01-01

    Germanium radiation detectors are manufactured by diffusing lithium into high purity p-type germanium. The diffusion is most readily accomplished from a lithium-lead-bismuth alloy at approximately 430°C and is monitored by a quartz half cell containing a standard composition of this alloy. Detectors having n-type cores may be constructed by converting high purity p-type germanium to n-type by a lithium diffusion

  11. Three-axis asymmetric radiation detector system

    DOEpatents

    Martini, Mario Pierangelo (Oak Ridge, TN); Gedcke, Dale A. (Oak Ridge, TN); Raudorf, Thomas W. (Oak Ridge, TN); Sangsingkeow, Pat (Knoxville, TN)

    2000-01-01

    A three-axis radiation detection system whose inner and outer electrodes are shaped and positioned so that the shortest path between any point on the inner electrode and the outer electrode is a different length whereby the rise time of a pulse derived from a detected radiation event can uniquely define the azimuthal and radial position of that event, and the outer electrode is divided into a plurality of segments in the longitudinal axial direction for locating the axial location of a radiation detection event occurring in the diode.

  12. Fast pyroelectric detector for broadband radiated power measurements

    SciTech Connect

    Cote, C.; DeSilva, A.W. [Institute for Plasma Research, University of Maryland, College Park, Maryland 20742-3511 (United States)] [Institute for Plasma Research, University of Maryland, College Park, Maryland 20742-3511 (United States)

    1996-12-01

    Basic design requirements are presented for pyroelectric detectors to be used effectively when the radiation source emits part or all of its power in the vacuum ultraviolet range, as is the case for a typical plasma in magnetic confinement fusion research. The difficulty associated with the VUV wavelength range lies in the high photoelectric yield of the associated energetic photons. A relatively inexpensive, commercially available detector was modified to eliminate the spurious currents resulting from photoelectrons. The modifications have little effect on the basic characteristics of the commercial detector (time response, sensitivity, etc). {copyright} {ital 1996 American Institute of Physics.}

  13. Radiation detectors as surveillance monitors for IAEA safeguards

    SciTech Connect

    Fehlau, P.E.; Dowdy, E.J.

    1980-10-01

    Radiation detectors used for personnel dosimetry are examined for use under IAEA Safeguards as monitors to confirm the passage or nonpassage (YES/NO) of plutonium-bearing nuclear material at barrier penetrations declared closed. In this application where backgrounds are ill defined, no advantage is found for a particular detector type because of intrinsic efficiency. Secondary considerations such as complexity, ease of tamper-proofing, and ease of readout are used to recommend specific detector types for routine monitoring and for data-base measurements. Recommendations are made for applications, data acquisition, and instrument development.

  14. The Dielectric Bolometer, A New Type of Thermal Radiation Detector

    NASA Technical Reports Server (NTRS)

    Hanel, R. A.

    1960-01-01

    Thermal detectors for the infrared, such as thermocouples and bolometers, are limited in their ultimate sensitivity predominantly by Johnson noise rather than temperature noise. Low noise figures are hard to achieve since Johnson noise preponderates temperature noise, which is the only essential noise for thermal detectors. The dielectric constants of some materials are sufficiently temperature dependent to make a new type of bolometer feasible. The basic theory of a dielectric bolometer, as shown here, promises noise figures below 3 decibels even at chopper frequencies well above the 1/tau value of the detector. Ferroelectrics such as barium-strontium titanate and others seem to be well suited for radiation-cooled dielectric bolometers.

  15. R&D for Better Nuclear Security: Radiation Detector Materials

    SciTech Connect

    Kammeraad, J E

    2009-04-02

    I am going to talk about the need for better materials for radiation detectors. I believe that government investment in this area can enable transformational technology change that could impact domestic nuclear security and also national nuclear security in some very positive and powerful ways. I'm not going to give you a lecture on how radiation detectors work, but I am going to tell you a bit about today's off-the-shelf technology and why it is not sufficient, what we need, and what security benefit you could get from improvements. I think we're at a critical point in time for some very impactful investments. In particular I'm going to focus on the use of gamma-ray radiation detectors at ports of entry. Not long before DHS was formed, Congress decreed that counter measures against the delivery of radiological and nuclear threats would be put in place at US ports of entry, under the authority of US Customs (later Customs and Border Protection in DHS). This included the screening of all cars and trucks passing through a port of entry. Existing off-the-shelf radiation detectors had to be selected for this purpose. Plans were made to make the most of the available technologies, but there are some inherent limitations of these detectors, plus the operational setting can bring out other limitations.

  16. Radiation detector for use in nuclear reactors

    SciTech Connect

    Cisco, T.C.; Grimaila, A.G.

    1981-09-08

    A multi-sensor radiation detection system for removable insertion into a nuclear reactor is described in which one conductor of all the sensors is a single, common element. This single common element is contained within a tubular metallic sheath and in crosssection comprises a multiple radial armed metallic conductor having a star shaped cross-section dimensioned to form wedgeshaped compartments throughout the active radiation detecting length of the metallic sheath.

  17. Radiation hardness of polysulphone and polycarbonate elements for LHC detectors

    E-print Network

    Hauviller, Claude; Bychkov, V; Golikov, V V; Kekelidze, G D; Lobastov, S P; Luschikov, V I; Peshekhonov, V D

    1998-01-01

    In the TRT Inner Detector being developed for ATLAS, elements made from plastic materials are widely used. In order to meet necessary requirements of the construction, these materials should have a high radiation hardness. This work presents a study of mechanical features of polysulphone and polycarbonate in dependence on the radiation dose. The results of measurements have shown a weak dependence of mechanical properties of polysulphone and polycarbonate on the absorbed dose up to the value of 1 MGy. So, the products from these materials could be used to construct detectors at LHC, at least on the mechanical point of view.

  18. Transition-radiation-Compton-scattering detector for very relativistic nuclei

    NASA Technical Reports Server (NTRS)

    Osborne, W. Z.; Mack, J. E.

    1975-01-01

    The paper presents the design and predicted performance of a large acceptance (2 sq m sr) transition-radiation-Compton-scattering detector system which can be used to measure energy spectra up to several thousand Gev/nucleon for nuclei with Z between 6 and 28, as well as up to 40,000 GeV/nucleon for He. The following circumstances made such a detector system practicable: (1) transition radiation output is proportional to the square of particle charge; (2) output varies at least as rapidly as the square of Lorentz factor over the range from several hundred to several thousand.

  19. Performance of the E715 transition radiation detector

    SciTech Connect

    Denisov, A.; Grachev, V.; Kulikov, A.; Schegelsky, V.; Seliverstov, D.; Smirnov, N.; Terentyev, N.; Tkatch, I.; Vorobyov, A.; Hsueh, S.Y.

    1984-01-01

    The transition radiation detector (TRD) consisted of 12 identical modules, each containing a radiator and a multiwire proportional counter (MWPC). A TRD is found to be an effective device for the identification of electrons in a large hadron background at Tevatron energies. The TRD proved to be a stable and reliable device with performance parameters in close agreement with theoretical predictions. The combination of a TRD with a lead glass calorimeter proved to be a very powerful method of electron identification. (LEW)

  20. Practical theory of the multilayered transition radiation detector

    Microsoft Academic Search

    X. Artru; G. B. Yodh; G. Mennessier

    1975-01-01

    The transition-radiation detector with a multifoil radiator for ultrarelativistic particles is studied in the following aspects: X-ray spectrum, Lorentz-factor (gamma) dependence, interference effects, saturation at high gamma, effects of irregularities, and multiple scattering. The analysis is simplified by reducing the various parameters to essentially three dimensionless quantities: a scaled Lorentz factor, a scaled frequency, and the ratio of foil spacing

  1. Recent progress in the transition radiation detector techniques

    NASA Technical Reports Server (NTRS)

    Yuan, L. C. L.

    1973-01-01

    A list of some of the major experimental achievements involving charged particles in the relativistic region are presented. With the emphasis mainly directed to the X-ray region, certain modes of application of the transition radiation for the identification and separation of relativistic charged particles are discussed. Some recent developments in detection techniques and improvements in detector performances are presented. Experiments were also carried out to detect the dynamic radiation, but no evidence of such an effect was observed.

  2. Semiconductor radiation detector with internal gain

    DOEpatents

    Iwanczyk, Jan (Los Angeles, CA); Patt, Bradley E. (Sherman Oaks, CA); Vilkelis, Gintas (Westlake Village, CA)

    2003-04-01

    An avalanche drift photodetector (ADP) incorporates extremely low capacitance of a silicon drift photodetector (SDP) and internal gain that mitigates the surface leakage current noise of an avalanche photodetector (APD). The ADP can be coupled with scintillators such as CsI(Tl), NaI(Tl), LSO or others to form large volume scintillation type gamma ray detectors for gamma ray spectroscopy, photon counting, gamma ray counting, etc. Arrays of the ADPs can be used to replace the photomultiplier tubes (PMTs) used in conjunction with scintillation crystals in conventional gamma cameras for nuclear medical imaging.

  3. BIBLIOGRAPHY ON SEMICONDUCTOR NUCLEAR RADIATION DETECTORS

    Microsoft Academic Search

    J. L. Blankenship; H. D. comps. Raleigh

    1962-01-01

    A bibliography on the theory, manufacture, properties, performance, and ; utilization of semiconductor materials for the detection of nuclear radiation is ; presented. The 464 references cover reports and published literature through ; January 1962. The report references are arranged alpha-numerically by report ; number behind the name of the issuing agency. The journal references are ; arranged alphabetically by

  4. EFFECTS OF P / N IN HOMOGENEITY ON CDZNTE RADIATION DETECTORS.

    SciTech Connect

    CHU,M.; TERTERIAN,S.; TING,D.; JAMES,R.B.; SZAWLOWSKI,M.; VISSER,G.J.

    2002-07-08

    Spectrometer grade, room-temperature radiation detectors have been produced on Cd{sub 0.90}Zn{sub 0.10}Te grown by the low-pressure Bridgman technique. Small amount of indium has been used to compensate the uncompensated Cd vacancies for the crystals to be semi-insulating. The properties of the detectors are critically dependent on the amount of excess Te introduced into the growth melts of the Cd{sub 0.90}Zn{sub 0.10}Te crystals and the best detectors are fabricated from crystals grown with 1.5% excess Te. Detector resolution of {sup 57}Co and {sup 241}Am radiation peaks are observed on all detectors except the ones produced on Cd{sub 0.90}Zn{sub 0.10}Te grown from the melt in the stoichiometric condition. The lack of resolution of these stoichiometric grown detectors is explained by a p/n conduction-type inhomogeneity model.

  5. Electronics and data acquisition in radiation detectors for medical imaging

    Microsoft Academic Search

    João Varela

    2004-01-01

    Electronics and data acquisition systems are important components of radiation detectors applied to medical imaging. The performance of these systems has strong implications on crucial parameters of imaging devices, like the sensitivity and the image background noise. The paper presents a review of the functionality, typical architectures and main components of the electronics and data acquisition systems in medical imaging.

  6. IceCube: A Cubic Kilometer Radiation Detector

    E-print Network

    Spencer R. Klein; for the IceCube Collaboration

    2008-12-01

    IceCube is a 1 km^3 neutrino detector now being built at the Amundsen-Scott South Pole Station. It consists of 4800 Digital Optical Modules (DOMs) which detect Cherenkov radiation from the charged particles produced in neutrino interactions. IceCube will observe astrophysical neutrinos with energies above about 100 GeV. IceCube will be able to separate \

  7. Characterization of thallium bromide crystals for radiation detector applications

    Microsoft Academic Search

    K. Hitomi; M Matsumoto; O Muroi; T Shoji; Y Hiratate

    2001-01-01

    In this study, thallium bromide (TlBr) crystals have been investigated for radiation detector applications. Thallium bromide crystals have been grown by the traveling molten zone method using materials purified by the conventional zone refining method. The grown crystals have been characterized in terms of their structural properties, stoichiometry and surface properties. Charge transport properties of the grown crystals have also

  8. Radiation Response of Emerging High Gain, Low Noise Detectors

    NASA Technical Reports Server (NTRS)

    Becker, Heidi N.; Farr, William H; Zhu, David Q.

    2007-01-01

    Data illustrating the radiation response of emerging high gain, low noise detectors are presented. Ionizing dose testing of silicon internal discrete avalanche photodiodes, and 51-MeV proton testing of InGaAs/InAlAs avalanche photodiodes operated in Geiger mode are discussed.

  9. From Vacuum Fluctuations to Radiation: Accelerated Detectors and Black Holes

    Microsoft Academic Search

    S. Massar; R. Parentani

    1994-01-01

    The vacuum fluctuations that induce the transitions and the thermalisation of a uniformly accelerated two level atom are studied in detail. Their energy content is revealed through the weak measurement formalism of Aharonov et al. It is shown that each time the detector makes a transition it radiates a Minkowski photon. The same analysis is then applied to the conversion

  10. Mercuric iodide single crystals for nuclear radiation detectors

    Microsoft Academic Search

    Weitang Li; Zhenghui Li; Shifu Zhu; Shujun Yin; Beijun Zhao; Guanxiong Chen; Shi Yin; Hong Yuan; Huapeng Xu

    1996-01-01

    Large size HgI2 single crystals were grown using the modified temperature oscillation method with low dislocation densities in a relatively stable temperature environment. Radiation detectors were fabricated from the single crystals which showed good energy resolution with small polarization

  11. Mercuric iodide single crystal for nuclear radiation detectors

    Microsoft Academic Search

    Weitang Li; Zhenghui Li; Shifu Zhu; Shujun Yin; Beijun Zhao; Guanxiong Chen; Shi Yin; Hong Yuan; Huapeng Xu

    1995-01-01

    Large size HgI2 single crystals are grown using the modified temperature oscillation method with low dislocation densities in a relatively stable temperature environment. Radiation detectors are fabricated from the single crystals which show good energy resolution with small polarization

  12. Undoped high-resistivity cadmium telluride for nuclear radiation detectors

    Microsoft Academic Search

    R. Triboulet; Y. Marfaing; A. Cornet; P. Siffert

    1974-01-01

    Starting with highly purified feed material, single crystals of semiinsulating CdTe were grown by the use of the traveling heater method, without external chemical compensation. Evaluation of the crystals by the use of electrical and optical measurements showed decisive improvements in quality. Nuclear radiation detectors prepared by the use of this material resulted in an energy resolution (FWHM), at room

  13. A SMALL, LINEAR, WIDE RANGE NUCLEAR RADIATION DETECTOR

    Microsoft Academic Search

    T. A. Rabson

    1962-01-01

    A simple nuclear radiation detector is produced using a scintillation ; element and a CdS photoresistive cell, which possesses the properties of ; linearity over a wide energy range, small size, and energy independence. Several ; scintillation materials including NaI and Pilot B are tested. (auth);

  14. Research on radiation detectors, boiling transients, and organic lubricants

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The accomplishments of a space projects research facility are presented. The subjects discussed are: (1) a study of radiation resistant semiconductor devices, (2) synthesis of high temperature organic lubricants, (3) departure from phase equilibrium during boiling transients, (4) effects of neutron irradiation on defect state in tungsten, and (5) determination of photon response function of NE-213 liquid scintillation detectors.

  15. Two-dimensional position sensitive radiation detectors

    DOEpatents

    Mihalczo, J.T.

    1994-02-22

    Nuclear reaction detectors capable of position sensitivity with submillimeter resolution in two dimensions are each provided by placing arrays of scintillation or wavelength shifting optical fibers formed of a plurality of such optical fibers in a side-by-side relationship in X and Y directions with a layer of nuclear reactive material operatively associated with surface regions of the optical fiber arrays. Each nuclear reaction occurring in the layer of nuclear reactive material produces energetic particles for simultaneously providing a light pulse in a single optical fiber in the X oriented array and in a single optical fiber in the Y oriented array. These pulses of light are transmitted to a signal producing circuit for providing signals indicative of the X-Y coordinates of each nuclear event. 6 figures.

  16. Two-dimensional position sensitive radiation detectors

    DOEpatents

    Mihalczo, John T. (Oak Ridge, TN)

    1994-01-01

    Nuclear reaction detectors capable of position sensitivity with submillimeter resolution in two dimensions are each provided by placing arrays of scintillation or wave length shifting optical fibers formed of a plurality of such optical fibers in a side-by-side relationship in X and Y directions with a layer of nuclear reactive material operatively associated with surface regions of the optical fiber arrays. Each nuclear reaction occurring in the layer of nuclear reactive material produces energetic particles for simultaneously providing a light pulse in a single optical fiber in the X oriented array and in a single optical fiber in the Y oriented array. These pulses of light are transmitted to a signal producing circuit for providing signals indicative of the X-Y coordinates of each nuclear event.

  17. A radiation detector design mitigating problems related to sawed edges

    NASA Astrophysics Data System (ADS)

    Aurola, A.; Marochkin, V.; Tuuva, T.

    2014-12-01

    In pixelated silicon radiation detectors that are utilized for the detection of UV, visible, and in particular Near Infra-Red (NIR) light it is desirable to utilize a relatively thick fully depleted Back-Side Illuminated (BSI) detector design providing 100% Fill Factor (FF), low Cross-Talk (CT), and high Quantum Efficiency (QE). The optimal thickness of such detectors is typically less than 300?m and above 40?m and thus it is more or less mandatory to thin the detector wafer from the backside after the front side of the detector has been processed and before a conductive layer is formed on the backside. A TAIKO thinning process is optimal for such a thickness range since neither a support substrate on the front side nor lithographic steps on the backside are required. The conductive backside layer should, however, be homogenous throughout the wafer and it should be biased from the front side of the detector. In order to provide good QE for blue and UV light the conductive backside layer should be of opposite doping type than the substrate. The problem with a homogeneous backside layer being of opposite doping type than the substrate is that a lot of leakage current is typically generated at the sawed chip edges, which may increase the dark noise and the power consumption. These problems are substantially mitigated with a proposed detector edge arrangement which 2D simulation results are presented in this paper.

  18. Uncooled PEM detector of the CO II-laser radiation

    NASA Astrophysics Data System (ADS)

    Aliyev, A. A.; Ibragimov, T. I.; Ismailov, N. D.; Nasibov, I. A.; Huseynov, E. K.

    2007-05-01

    Uncooled photoelectromagnetic detectors (PEM-detector) on the basis of cadmium - mercury telluride solid solutions of composition x < 0.2 find application in opto-electronic systems with use of the C0 II-laser radiation with wave-length of 10.6 ?M. [1] To advantages of such detectors it is possible to attribute absence of an external electric supply that reduces a level of noise and considerably reduces thermal loading on photodetector as well as it is a high speed responsivity that allows to use them in heterodyne systems of registration. The theoretical calculations of parameters of PEM detector has been carried out and results of development and research of uncooled PEM-detector on basis of Cd xHg 1-xTe with x=0.2 of 6÷7 ?m range of spectrum are represented by us in paper [2]. At the heart of work the researches of parameters of the PEM detector depending on a level of acceptor doping of the semiconductor have been discounted. In the present work the results of research of an opportunity of increasing of parameters of the PEM detector on basis of Cd xHg 1-xTe with x = 0.167 corresponding to a maximum of spectral sensitivity on wave-length of 10.6 ?m at room temperature are represented.

  19. Three-dimensional architecture for solid state radiation detectors

    DOEpatents

    Parker, Sherwood (Berkeley, CA)

    1999-01-01

    A radiation-damage resistant radiation detector is formed on a substrate formed of a material doped with a first conductivity type dopant. The detector includes at least one first electrode formed of first conductivity type dopant, and at least one second electrode that is spaced-apart from the first electrode and formed of a second conductivity type dopant. Each first and second electrode penetrates into the substrate from a substrate surface, and one or more electrodes may penetrate entirely through the substrate, that is traversing from one surface to the other surface. Particulate and/or electromagnetic radiation penetrating at least a surface of the substrate releases electrons and holes in substrate regions. Because the electrodes may be formed entirely through the substrate thickness, the released charges will be a relatively small distance from at least a portion of such an electrode, e.g., a distance less than the substrate thickness. The electrons and/or holes traverse the small distance and are collected by said electrodes, thus promoting rapid detection of the radiation. By providing one or more electrodes with a dopant profile radially graded in a direction parallel to a substrate surface, an electric field results that promotes rapid collection of released electrons and said holes. Monolithic combinations of such detectors may be fabricated including CMOS electronics to process radiation signals.

  20. Three-dimensional architecture for solid state radiation detectors

    DOEpatents

    Parker, S.

    1999-03-30

    A radiation-damage resistant radiation detector is formed on a substrate formed of a material doped with a first conductivity type dopant. The detector includes at least one first electrode formed of first conductivity type dopant, and at least one second electrode that is spaced-apart from the first electrode and formed of a second conductivity type dopant. Each first and second electrode penetrates into the substrate from a substrate surface, and one or more electrodes may penetrate entirely through the substrate, that is traversing from one surface to the other surface. Particulate and/or electromagnetic radiation penetrating at least a surface of the substrate releases electrons and holes in substrate regions. Because the electrodes may be formed entirely through the substrate thickness, the released charges will be a relatively small distance from at least a portion of such an electrode, e.g., a distance less than the substrate thickness. The electrons and/or holes traverse the small distance and are collected by said electrodes, thus promoting rapid detection of the radiation. By providing one or more electrodes with a dopant profile radially graded in a direction parallel to a substrate surface, an electric field results that promotes rapid collection of released electrons and said holes. Monolithic combinations of such detectors may be fabricated including CMOS electronics to process radiation signals. 45 figs.

  1. Examination results of the Three Mile Island radiation detector HP-R-212

    SciTech Connect

    Mueller, G.M.

    1983-12-01

    Area radiation detector HP-R-212 was removed from the Three Mile Island containment building on November 13, 1981. The detector apparently started to fail during November 1979 and by the first part of December 1979 the detector readings had degraded from 1 R/hr to 20 mR/hr. This report discusses the cause of failure, detector radiation measurement characteristics, and our estimates of the total gamma radiation dose received by the detector electronics.

  2. Multi-directional radiation detector using photographic film

    NASA Astrophysics Data System (ADS)

    Junet, L. K.; Majid, Z. A. Abdul; Sapuan, A. H.; Sayed, I. S.; Pauzi, N. F.

    2014-11-01

    Ionising radiation has always been part of our surrounding and people are continuously exposed to it. Ionising radiation is harmful to human health, thus it is vital to monitor the radiation. To monitor radiation, there are three main points that should be observed cautiously, which are energy, quantity, and direction of the radiation sources. A three dimensional (3D) dosimeter is an example of a radiation detector that provide these three main points. This dosimeter is able to record the radiation dose distribution in 3D. Applying the concept of dose detection distribution, study has been done to design a multi-directional radiation detector of different filter thicknesses. This is obtained by designing a cylinder shaped aluminum filter with several layers of different thickness. Black and white photographic material is used as a radiation-sensitive material and a PVC material has been used as the enclosure. The device is then exposed to a radiation source with different exposure factors. For exposure factor 70 kVp, 16 mAs; the results have shown that optical density (OD) value at 135° is 1.86 higher compared with an OD value at 315° which is 0.71 as the 135° area received more radiation compare to 315° region. Furthermore, with an evidence of different angle of film give different value of OD shows that this device has a multidirectional ability. Materials used to develop this device are widely available in the market, thus reducing the cost of development and making it suitable for commercialisation.

  3. Advanced technology lunar telescopes III. Radiation resistant detectors

    SciTech Connect

    Payne, L.J.; Kimble, R.A.; Smith, A.M.; Haas, J.P.; Sturgell, C.C. Jr.; Wentink, R.E.; Carbone, J.; Chen, P.C.

    1993-01-01

    A practical lunar telescope requires high resolution imaging array detectors that are immune to (or can be easily shielded from) solar flare particle radiation and cosmic rays. Charge-coupled devices (CCDs), the detectors of choice for ground-based applications, fall short in this respect because of their high susceptibility to radiation induced bulk traps and loss of charge transfer efficiency (CTE). Blooming in CCDs also limits the dynamic range and degrades resolution, while the well known red leak problem hinders observations in the ultraviolet. The authors describe an ongoing program at NASA GSFC to develop intensified random-access Charge-Injection Devices (CIDs), a new generation of space uv detectors which do not have the shortcomings of CCDs. CIDs, like CCDs, are silicon array detectors. Unlike CCDs, however, CIDs have more than 100x greater tolerance to ionizing particle radiation. Since CIDs do not transfer charge, CTE degradation has very little effect on the overall sensitivity and noise level. CIDs can perform extremely fast windowing of selected regions of interest with high signal levels (e.g. bright cores of galaxies or strong emission lines, etc) while monitoring the remainder of the array at lower rates. This selective readout ability plus the lack of blooming give CIDs a high dynamic range of operation but with minimal demands on the memory storage and telemetry data bandwidth. The authors demonstrate the operation of a row-windowing CID and discuss the potential applications of these devices to astronomical research from the moon.

  4. Device for detachably securing a collimator to a radiation detector

    SciTech Connect

    Hanz, G.J.; Jung, G.; Pflaum, M.

    1986-12-16

    A device is described for detachably securing a collimator to a radiation detector, comprising: (a) a first annular groove means secured to the radiation detector; (b) a second annular groove means secured to the collimator; (c) a split ring having a first and second ring ends, the ring being received in the first annular groove means; and (d) a ring diameter control system, including (d1) a first lever system having two ends; (d2) a second lever system having two ends; and (d3) a rotating hub being rotatably secured to the detector head; wherein the first lever system is rotatably mounted with one end linked to the first ring end and with the other end linked to the rotating hub. The second lever system is rotatably mounted with one end linked to the second ring end and with the other end linked to the rotating hub, such that rotation of the rotating hub moves the first and second lever systems in opposite directions thereby moving the first and second ring ends between a first position, in which the split ring is positioned only in the first annular groove means, and a second position, in which the split ring is located in both the first annular groove means and the second annular groove means, thus attaching the collimator to the radiation detector.

  5. Transactions ACA: Volume 34 (1999) 11-25. SYNCHROTRON RADIATION AND DETECTORS: SYNERGISTS IN A DANCE

    E-print Network

    Gruner, Sol M.

    1 Transactions ACA: Volume 34 (1999) 11-25. SYNCHROTRON RADIATION AND DETECTORS: SYNERGISTS in the use of synchrotron radiation for crystallography has been driven as much by advances in detectors days or weeks to mere hours. Synchrotron radiation and better detectors together catalyzed advances

  6. Testing and Evaluation Protocol for Alarming Personal Radiation Detectors for Homeland Security

    E-print Network

    Perkins, Richard A.

    Testing and Evaluation Protocol for Alarming Personal Radiation Detectors for Homeland Security T Radiation Detectors for Homeland Security EFF. DATE 2010-11-09 REV. 2.02 PAGE 1 of 74 Testing and Evaluation Protocol Alarming Personal Radiation Detectors for use in Homeland Security 1. Scope This document

  7. Novel Radiation Detector Wins R&D 100 Award Brookhaven Lab recently

    E-print Network

    Novel Radiation Detector Wins R&D 100 Award Brookhaven Lab recently won an R&D 100 Award for Gamma-zinc-telluride (CZT) radiation detector that is coupled with novel low-noise pulse processing electron- ics and high of the Lab's Radiation Detector and Nonprliferation R&D Group, examine the components of Gamma

  8. Testing and Evaluation Protocol for Spectroscopic Personal Radiation Detectors (SPRDs) for Homeland

    E-print Network

    Perkins, Richard A.

    Testing and Evaluation Protocol for Spectroscopic Personal Radiation Detectors (SPRDs) for Homeland Radiation Detectors (SPRDs) for Homeland Security. EFF. DATE 2010-11-09 REV. 1.02 PAGE 1 of 94 Testing and Evaluation Protocol Alarming Personal Radiation Detectors for use in Homeland Security 1. Scope This document

  9. Subnanosecond ellipticity detector for laser radiation S. D. Ganichev,a

    E-print Network

    Ganichev, Sergey

    Subnanosecond ellipticity detector for laser radiation S. D. Ganichev,a J. Kiermaier, W. Weber, S online 27 August 2007 A room temperature detector of terahertz laser radiation ellipticity has been- biased semiconductor detector elements in response to laser radiation. The first element provides

  10. Detector measures power in 50 to 30,000 GHz radiation band

    NASA Technical Reports Server (NTRS)

    Arams, F. R.; Wang, M. T.

    1966-01-01

    Broadband power detector assembly measures electromagnetic radiation in the 50 to 30,000 GHz band. The assembly includes a matched pair of detectors which incorporate thin-film radiation absorbers. The detector is effective with either coherent or incoherent radiation.

  11. Testing and Evaluation Protocol for Alarming Personal Radiation Detectors for Homeland Security

    E-print Network

    Testing and Evaluation Protocol for Alarming Personal Radiation Detectors for Homeland Security T Radiation Detectors for Homeland Security EFF. DATE 2013-05-17 REV. 3.00 PAGE 1 of 5 Testing and Evaluation Protocol Alarming Personal Radiation Detectors for use in Homeland Security 1. Scope This document

  12. Testing and Evaluation Protocol for Spectroscopic Personal Radiation Detectors (SPRDs) for Homeland

    E-print Network

    Testing and Evaluation Protocol for Spectroscopic Personal Radiation Detectors (SPRDs) for Homeland Radiation Detectors (SPRDs) for Homeland Security. EFF. DATE 2013-05-30 REV. 2.00 PAGE 1 of 5 Testing and Evaluation Protocol Alarming Personal Radiation Detectors for use in Homeland Security 1. Scope This document

  13. Optimization of efficiency and response time of diffusion-based nuclear radiation detectors

    Microsoft Academic Search

    S. E. Wouters; T. Otaredian; E. M. Schooneveld

    1991-01-01

    The charge collection process in a diffusion-based silicon nuclear radiation detector was investigated by illuminating the detector at the backside with optical radiation. The results are compared to calculations and show good agreement. The collection mechanism is characterized, and the detector response to nuclear radiation and its optimum with respect to efficiency and response time are calculated. Efficiency and response

  14. IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 57, NO. 6, DECEMBER 2010 3795 Femtosecond Radiation Experiment Detector

    E-print Network

    Gruner, Sol M.

    IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 57, NO. 6, DECEMBER 2010 3795 Femtosecond Radiation, radiation detectors, semicon- ductor device measurement, silicon radiation detectors, X-ray de- tector, X Experiment Detector for X-Ray Free-Electron Laser (XFEL) Coherent X-Ray Imaging Hugh T. Philipp, Lucas J

  15. Radiation Particle Assessment with Pixel Detectors for Tissue Interpretation

    NASA Astrophysics Data System (ADS)

    Saganti, Premkumar

    Most recently, we have started radiation particle assessment studies making use of CMOS detec-tor systems as a collaborative project between Prairie View AM University and NASA Johnson Space Center. These imaging detectors are being developed at NASA-JSC by Holland et al., (2007-2009) and preliminary data collection with primary neutron beam and secondary particles are being obtained at Los Alamos National Laboratory (LANL) by Saganti et al., (2007-2009). Interpretation of the radiation data at pixel level and particle trajectory is expected to provide additional information for more precise understanding of the radiation damage at tissue level. Such developments and applications provide promise to be used and implemented for several space exploration objectives in characterizing the radiation environment and their influence on biological tissue samples at micron level (current prototypes are about 4-6 microns). We present our preliminary research protocols and results from these studies and introduce the detector systems for 3D-tissue damage interpretation with neutrons (100-800 MeV).

  16. Variable-Temperature Cryostat For Radiation-Damage Testing Of Germanium Detectors

    NASA Technical Reports Server (NTRS)

    Floyd, Samuel R.; Puc, Bernard P.

    1992-01-01

    Variable-temperature cryostats developed to study radiation damage to, and annealing of, germanium gamma-ray detectors. Two styles: one accommodates large single detector and one accommodates two medium-sized detectors. New cryostats allow complete testing of large-volume germanium gamma-ray detectors without breaking cryostat vacuum and removing detectors for annealing.

  17. Examination system utilizing ionizing radiation and a flexible, miniature radiation detector probe

    Microsoft Academic Search

    Stanislaw Majewski; Brian J. Kross; Carl J. Zorn; Lukasz A. Majewski

    1996-01-01

    An optimized examination system and method based on the Reverse Geometry X-Ray.RTM. (RGX.RTM.) radiography technique are presented. The examination system comprises a radiation source, at least one flexible, miniature radiation detector probe positioned in appropriate proximity to the object to be examined and to the radiation source with the object located between the source and the probe, a photodetector device

  18. Examination system utilizing ionizing radiation and a flexible, miniature radiation detector probe

    Microsoft Academic Search

    S. Majewski; B. J. Kross; C. J. Zorn; L. A. Majewski

    1996-01-01

    An optimized examination system and method based on the Reverse Geometry X-Ray{trademark} (RGX{trademark}) radiography technique are presented. The examination system comprises a radiation source, at least one flexible, miniature radiation detector probe positioned in appropriate proximity to the object to be examined and to the radiation source with the object located between the source and the probe, a photodetector device

  19. Charge transport properties of CdMnTe radiation detectors

    NASA Astrophysics Data System (ADS)

    Rafiei, R.; Boardman, D.; Reinhard, M. I.; Sarbutt, A.; Kim, K.; Watt, G. C.; Uxa, S.; Prokopovich, D. A.; Belas, E.; Bolotnikov, A. E.; James, R. B.

    2012-10-01

    Growth, fabrication and characterization of indium-doped cadmium manganese telluride (CdMnTe) radiation detectors have been described. Alpha-particle spectroscopy measurements and time resolved current transient measurements have yielded an average charge collection efficiency approaching 100 %. Spatially resolved charge collection efficiency maps have been produced for a range of detector bias voltages. Inhomogeneities in the charge transport of the CdMnTe crystals have been associated with chains of tellurium inclusions within the detector bulk. Further, it has been shown that the role of tellurium inclusions in degrading charge collection is reduced with increasing values of bias voltage. The electron drift velocity was calculated from the rise time distribution of the preamplifier output pulses at each measured bias. From the dependence of drift velocity on applied electric field the electron mobility was found to be ?n = (718 ± 55) cm2/Vs at room temperature.

  20. Charge transport properties of CdMnTe radiation detectors

    SciTech Connect

    Kim K.; Rafiel, R.; Boardman, M.; Reinhard, I.; Sarbutt, A.; Watt, G.; Watt, C.; Uxa, S.; Prokopovich, D.A.; Belas, E.; Bolotnikov, A.E.; James, R.B.

    2012-04-11

    Growth, fabrication and characterization of indium-doped cadmium manganese telluride (CdMnTe)radiation detectors have been described. Alpha-particle spectroscopy measurements and time resolved current transient measurements have yielded an average charge collection efficiency approaching 100 %. Spatially resolved charge collection efficiency maps have been produced for a range of detector bias voltages. Inhomogeneities in the charge transport of the CdMnTe crystals have been associated with chains of tellurium inclusions within the detector bulk. Further, it has been shown that the role of tellurium inclusions in degrading chargecollection is reduced with increasing values of bias voltage. The electron transit time was determined from time of flight measurements. From the dependence of drift velocity on applied electric field the electron mobility was found to be n = (718 55) cm2/Vs at room temperature.

  1. Super-thin single crystal diamond membrane radiation detectors

    SciTech Connect

    Pomorski, Michal; Caylar, Benoit; Bergonzo, Philippe [CEA-LIST, Diamond Sensors Laboratory, Gif-sur-Yvette F-91191 (France)] [CEA-LIST, Diamond Sensors Laboratory, Gif-sur-Yvette F-91191 (France)

    2013-09-09

    We propose to use the non-electronic grade (nitrogen content 5 ppb < [N] < 5 ppm) single crystal (sc) chemical vapour deposited (CVD) diamond as a thin-membrane radiation detector. Using deep Ar/O{sub 2} plasma etching it is possible to produce self-supported few micrometres thick scCVD membranes of a size approaching 7 mm × 7 mm, with a very good surface quality. After metallization and contacting, electrical properties of diamond membrane detectors were probed with 5.486 MeV ?-particles as an ionization source. Despite nitrogen impurity, scCVD membrane detectors exhibit stable operation, charge collection efficiency close to 100%, with homogenous response, and extraordinary dielectric strength up to 30 V/?m.

  2. Modeling radiation loads to detectors in a SNAP mission

    SciTech Connect

    Nikolai V. Mokhov et al.

    2004-05-12

    In order to investigate degradation of optical detectors of the Supernova Acceleration Project (SNAP) space mission due to irradiation, a three-dimensional model of the satellite has been developed. Realistic radiation environment at the satellite orbit, including both galactic and trapped in radiation belts cosmic rays, has been taken into account. The modeling has been performed with the MARS14 Monte Carlo code. In a current design, the main contribution to dose accumulated in the photodetectors is shown to be due to trapped protons. A contribution of primary {alpha}-particles is estimated. Predicted performance degradation for the photo-detector for a 4-year space mission is 40% and can be reduced further by means of shielding optimization.

  3. Synchrotron radiation computed laminography using an inclined detector.

    PubMed

    Zhang, Jie; Li, Gang; Yi, Qiru; Chen, Yu; Gao, Zhenhua; Jiang, Xiaoming

    2015-01-01

    Synchrotron radiation computed laminography (SR-CL) has been in use in three-dimensional non-destructive imaging of flat objects for several years. A new set-up is proposed based on the traditional SR-CL method but with the detector inclined at the same angle as the sample inclination to collect projections. The results of computer simulations and real-sample experiments demonstrate that reconstructions acquired using an inclined detector are of better quality compared with those acquired using ordinary detecting methods, especially for the situation of few projections and small difference of attenuation ratio of the sample. This method could be applied to obtain high-quality images of weak-contrast samples with short measurement time and mild radiation damage. PMID:25537599

  4. Experiences with radiation portal detectors for international rail transport

    NASA Astrophysics Data System (ADS)

    Stromswold, D. C.; McCormick, K.; Todd, L.; Ashbaker, E. D.; Evans, J. C.

    2006-08-01

    Radiation detectors monitored trains at two international borders to evaluate the performance of NaI(Tl) and plastic (polyvinyltoluene: PVT) gamma-ray detectors to characterize rail cargo. The detectors included a prototype NaI(Tl) radiation-portal-monitor panel having four large detectors (10-cm × 10-cm × 41-cm) and a PVT panel with a 41 cm × 173 cm × 3.8-cm detector. Spectral data from the NaI(Tl) and PVT detectors were recorded. Of particular emphasis was the identification of naturally occurring radioactive material (NORM) and the resultant frequency of nuisance alarms. For rail monitoring, the difficulty in stopping trains to perform secondary inspection on alarming cars creates a need for reliable identification of NORM during initial screening. Approximately 30 trains were monitored, and the commodities in individual railcars were ascertained from manifest information. At one test site, the trains carried inter-modal containers that had been unloaded from ships, and at the other site, the trains contained bulk cargo in tanker cars and hopper cars or individual items in boxcars or flatbeds. NORM encountered included potash, liquefied petroleum gas, fireworks, televisions, and clay-based products (e.g., pottery). Analysis of the spectral data included the use of the template-fitting portion of the program GADRAS developed at Sandia National Laboratories. For most of the NORM, the NaI(Tl) data produced a correct identification of the radionuclides present in the railcars. The same analysis was also used for PVT data in which the spectral information (no peaks but only gradual spectral changes including Compton edges) was limited. However, the PVT analysis provided correct identification of 40K and 226Ra in many cases.

  5. Experiences with radiation portal detectors for international rail transport

    SciTech Connect

    Stromswold, David C.; McCormick, Kathleen R.; Todd, Lindsay C.; Ashbaker, Eric D.; Evans, J. C.

    2006-08-30

    Radiation detectors monitored trains at two international borders to evaluate the performance of NaI(Tl) and plastic (polyvinyltoluene: PVT) gamma-ray detectors to characterize rail cargo. The detectors included a prototype NaI(Tl) radiation-portal-monitor panel having four large detectors (10-cm × 10-cm × 41-cm) and a PVT panel with a 41 cm × 173 cm × 3.8-cm detector. Spectral data from the NaI(Tl) and PVT detectors were recorded. Of particular emphasis was the identification of naturally occurring radioactive material (NORM) and the resultant frequency of nuisance alarms. For rail monitoring, the difficulty in stopping trains to perform secondary inspection on alarming cars creates a need for reliable identification of NORM during initial screening. Approximately 30 trains were monitored, and the commodities in individual railcars were ascertained from manifest information. At one test site the trains carried inter-modal containers that had been unloaded from ships, and at the other site the trains contained bulk cargo or individual items in boxcars or flatbeds. NORM encountered included potash, liquefied petroleum gas, fireworks, televisions, and clay-based products (e.g., pottery). Analysis of the spectral data included the use of the template-fitting program GADRAS/FitToDB from Sandia National Laboratories. For much of the NORM the NaI(Tl) data produced a correct identification of the radionuclides present in the railcars. The same analysis was also used for PVT data in which the spectral information (no peaks but only gradual spectral changes including Compton edges) was limited. However, the PVT analysis provided correct identification of 40K and 226Ra in many cases.

  6. A precision synchrotron radiation detector using phosphorescent screens

    SciTech Connect

    Jung, C.K.; Lateur, M.; Nash, J.; Tinsman, J. (Stanford Linear Accelerator Center, Menlo Park, CA (USA)); Butler, J. (Fermi National Accelerator Lab., Batavia, IL (USA)); Wormser, G. (Paris-11 Univ., 91 - Orsay (France). Lab. de l'Accelerateur Lineaire); Levi, M.; Rouse, F. (Lawrence Berkeley Lab., CA (USA))

    1990-01-01

    A precision detector to measure synchrotron radiation beam positions has been designed and installed as part of beam energy spectrometers at the Stanford Linear Collider (SLC). The distance between pairs of synchrotron radiation beams is measured absolutely to better than 28 {mu}m on a pulse-to-pulse basis. This contributes less than 5 MeV to the error in the measurement of SLC beam energies (approximately 50 GeV). A system of high-resolution video cameras viewing precisely aligned fiducial wire arrays overlaying phosphorescent screens has achieved this accuracy. 3 refs., 5 figs., 1 tab.

  7. Performance of the AMS-02 Transition Radiation Detector

    E-print Network

    P. v. Doetinchem; S. Fopp; W. Karpinski; T. Kirn; K. Luebelsmeyer; J. Orboeck; S. Schael; A. Schultz von Dratzig; G. Schwering; T. Siedenburg; R. Siedling; W. Wallraff; U. Becker; J. Burger; R. Henning; A. Kounine; V. Koutsenko; J. Wyatt

    2006-08-29

    For cosmic particle spectroscopy on the International Space Station the AMS experiment will be equipped with a Transition Radiation Detector (TRD) to improve particle identification. The TRD has 20 layers of fleece radiator with Xe/CO2 proportional mode straw tube chambers. They are supported in a conically shaped octagon structure made of CFC-Al-honeycomb. For low power consumption VA analog multiplexers are used as front-end readout. A 20 layer prototype built from final design components has achieved proton rejections from 100 to 2000 at 90% electron efficiency for proton beam energies up to 250 GeV with cluster counting, likelihood and neural net selection algorithms.

  8. Calibration of the active radiation detector for Spacelab-One

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The flight models of the active radiation detector (ARD) for the ENV-01 environmental monitor were calibrated using gamma radiation. Measured sensitivities of the ion chambers were 6.1 + or - 0.3 micron rad per count for ARD S/N1, and 10.4 + or - 0.5 micron rad per count for ARD S/N2. Both were linear over the measured range 0.10 to 500 m/rad hour. The particle counters (proportional counters) were set to respond to approximately 85% of minimum ionizing particles of unit charge passing through them. These counters were also calibrated in the gamma field.

  9. CMOS sensor as charged particles and ionizing radiation detector

    NASA Astrophysics Data System (ADS)

    Cruz-Zaragoza, E.; Piña López, I.

    2015-01-01

    This paper reports results of CMOS sensor suitable for use as charged particles and ionizing radiation detector. The CMOS sensor with 640 × 480 pixels area has been integrated into an electronic circuit for detection of ionizing radiation and it was exposed to alpha particle (Am-241, Unat), beta (Sr-90), and gamma photons (Cs-137). Results show after long period of time (168 h) irradiation the sensor had not loss of functionality and also the energy of the charge particles and photons were very well obtained.

  10. Radiation damage of the HEAO C-1 germanium detectors

    NASA Technical Reports Server (NTRS)

    Mahoney, W. A.; Ling, J. C.; Jacobson, A. S.

    1981-01-01

    The effects of radiation damage from proton bombardment of the four HEAO C-1 high purity germanium detectors have been measured and compared to predictions. Because of the presence of numerous gamma-ray lines in the detector background spectra and because of the relatively long exposure time of the HEAO 3 satellite to cosmic-ray and trapped protons, it has been possible to measure both the energy and time dependence of radiation damage. After 100 d in orbit, each of the four detectors has been exposed to approximately 3 x 10 to the 7th protons/sq cm, and the average energy resolution at 1460 keV had degraded from 3.2 keV fwhm to 8.6 keV fwhm. The lines were all broadened to the low energy side although the line profile was different for each of the four detectors. The damage-related contribution to the degradation in energy resolution was found to be linear in energy and proton influence.

  11. Improved spectrometric characteristics of thallium bromide nuclear radiation detectors

    Microsoft Academic Search

    K. Hitomi; T. Murayama; T. Shoji; T. Suehiro; Y. Hiratate

    1999-01-01

    Thallium bromide (TlBr) is a compound semiconductor with a high atomic number and wide band gap. In this study, nuclear radiation detectors have been fabricated from the TlBr crystals. The TlBr crystals were grown by the horizontal travelling molten zone (TMZ) method using the materials purified by many pass zone refining. The crystals were characterized by measuring the resistivity, the

  12. Protective surface coatings on semiconductor nuclear radiation detectors

    Microsoft Academic Search

    W. L. Hansen; E. E. Haller; G. S. Hubbard

    1980-01-01

    Surface states on germanium p-i-n junctions have been investigated using deep level transient spectroscopy (DLTS) and collimated beams of 60 keV gamma-rays. The DLTS spectra have a characteristic signature for each surface treatment but the spectra are complex and not readily interpretable as to suitability for radiation detectors. Collimated gamma-ray beams give a direct measure of surface channel effects and

  13. Protective surface coatings on semiconductor nuclear radiation detectors

    Microsoft Academic Search

    W. L. Hansen; E. E. Haller; G. S. Hubbard

    1979-01-01

    Surface states on germanium p-i-n junctions have been investigated using deep level transient spectroscopy (DLTS) and collimated beams of 60 keV gamma-rays. The DLTS spectra have a characteristic signature for each surface treatment but the spectra are complex and not readily interpretable as to suitability for radiation detectors. Collimated gamma-ray beams give a direct measure of surface channel effects and

  14. Double gated-integrator for shaping nuclear radiation detector signals

    Microsoft Academic Search

    J. Gál

    2001-01-01

    A new shaper, the double gated-integrator, for shaping nuclear radiation detector signals is investigated both theoretically and experimentally. The double gated-integrator consists of a pre-filter and two cascaded gated integrators. Two kinds of pre-filters were considered: a rectangular one and an exponential one. The results of the theoretical calculation show that the best figure of demerit for the double gated-integrator

  15. Simple classical model for Fano statistics in radiation detectors

    NASA Astrophysics Data System (ADS)

    Jordan, David V.; Renholds, Andrea S.; Jaffe, John E.; Anderson, Kevin K.; René Corrales, L.; Peurrung, Anthony J.

    2008-02-01

    A simple classical model that captures the essential statistics of energy partitioning processes involved in the creation of information carriers (ICs) in radiation detectors is presented. The model pictures IC formation from a fixed amount of deposited energy in terms of the statistically analogous process of successively sampling water from a large, finite-volume container ("bathtub") with a small dipping implement ("shot or whiskey glass"). The model exhibits sub-Poisson variance in the distribution of the number of ICs generated (the "Fano effect"). Elementary statistical analysis of the model clarifies the role of energy conservation in producing the Fano effect and yields Fano's prescription for computing the relative variance of the IC number distribution in terms of the mean and variance of the underlying, single-IC energy distribution. The partitioning model is applied to the development of the impact ionization cascade in semiconductor radiation detectors. It is shown that, in tandem with simple assumptions regarding the distribution of energies required to create an (electron, hole) pair, the model yields an energy-independent Fano factor of 0.083, in accord with the lower end of the range of literature values reported for silicon and high-purity germanium. The utility of this simple picture as a diagnostic tool for guiding or constraining more detailed, "microscopic" physical models of detector material response to ionizing radiation is discussed.

  16. Radiation tests for a single-GEM-loaded gaseous detector

    NASA Astrophysics Data System (ADS)

    Lee, Kyong Sei; Hong, Byungsik; Park, Sung Keun; Kim, Sang Yeol

    2014-11-01

    We report on a systematic study of a single-gas-electron-multiplier (GEM)-loaded gaseous detector developed for precision measurements of high-energy particle beams and for dose verification in particle therapy. In the present study, a 256-channel prototype detector having an active area of 16 × 16 cm2 and operating using a continuous current-integration-mode signal-processing method was manufactured and tested with X-rays emitted from a 70-kV X-ray generator and 43-MeV protons provided by the MC50 proton cyclotron at the Korea Institute of Radiological and Medical Science (KIRAMS). The amplified detector response was measured for X-rays with an intensity of about 5 × 106 Hz cm-2. The linearity of the detector response to the particle flux was examined and validated by using 43-MeV proton beams. The non-uniform development of the amplification for the gas electrons in space was corrected by applying a proper calibration to the channel responses of the measured beam-profile data. We conclude from the radiation tests that the detector developed in the present study will allow us to perform quality measurements of various high-energy particle beams and to apply the technology to dose-verification measurements in particle therapy.

  17. Study of contacts to CdZnTe radiation detectors

    NASA Astrophysics Data System (ADS)

    Nemirovsky, Y.; Ruzin, A.; Asa, G.; Gorelik, Y.; Li, L.

    1997-06-01

    This study characterizes, for the first time, contacts to CdZnTe radiation detectors by measuring the dark noise spectra as a function of the applied bias. The noise currents are correlated with the dc dark current-voltage characteristics of CdZnTe x-ray and gamma-ray detectors. In order to identify and separate the role of the contacts in the overall performance, the measured noise phenomena is correlated with detector configuration and contact design as well as the growth method of the CdZnTe crystals, contact technology, and passivation. Several contact technologies (electroless gold, and a number of evaporated metallic contacts including gold, indium, zinc, titanium, aluminum, and platinum contacts) are compared. Contacts to CdZnTe crystals grown by high pressure Bridgman are compared with contacts to CdZnTe crystals grown by modified Bridgman. Contacts of resistive detectors as well as of Schottky detectors are reported. Large area symmetric contacts are compared with small area pixelized contacts. The role of the metallization used for contacts, the role of surface effects and passivation, and the role of contact design are discussed.

  18. Distinguishing Neutrons and Gammas with MSL's Radiation Assessment Detector (RAD)

    NASA Astrophysics Data System (ADS)

    Guo, J.; Hassler, D.; Wimmer-Schweingruber, R. F.; Zeitlin, C.; Boettcher, S.; Martin, C.; Brinza, D.; Koehler, J.; Böhm, E.; Kharytonov, A.; Ehresmann, B.

    2012-12-01

    The radiation environment on the Martian surface is a complex mixture of charged primary and secondary radiation and of neutral secondary radiation. This neutral component amounts to a significant fraction of the surface radiation field and consists of neutrons and gamma rays. The neutron component is especially important from a radiation protection point of view, but is experimentally difficult to distinguish from the gamma rays. The Radiation Assessment Detector (RAD) on Mars Science Laboratory's (MSL's) rover Curiosity measures both neutrons and gammas. It consists of a compact arrangement of a dense, more gamma-sensitive CsI sctintillator, and a high-proton-content plastic scintillator, which in turn is more sensitive to neutrons. Using sophisticated inversion techniques, the RAD measurements can be inverted to provide reliable estimates for the neutron and gamma spectra on Mars. In this work we will discuss the status of the inversion techniques and calibration data, and relate them with predictions for the neutral component of the Martian surface radiation field.

  19. System for determining the type of nuclear radiation from detector output pulse shape

    DOEpatents

    Miller, William H. (Columbia, MO); Berliner, Ronald R. (Columbia, MO)

    1994-01-01

    A radiation detection system determines the type of nuclear radiation received in a detector by producing a correlation value representative of the statistical cross correlation between the shape of the detector signal and pulse shape data previously stored in memory and characteristic of respective types of radiation. The correlation value is indicative of the type of radiation. The energy of the radiation is determined from the detector signal and is used to produce a spectrum of radiation energies according to radiation type for indicating the nature of the material producing the radiation.

  20. System for determining the type of nuclear radiation from detector output pulse shape

    DOEpatents

    Miller, W.H.; Berliner, R.R.

    1994-09-13

    A radiation detection system determines the type of nuclear radiation received in a detector by producing a correlation value representative of the statistical cross correlation between the shape of the detector signal and pulse shape data previously stored in memory and characteristic of respective types of radiation. The correlation value is indicative of the type of radiation. The energy of the radiation is determined from the detector signal and is used to produce a spectrum of radiation energies according to radiation type for indicating the nature of the material producing the radiation. 2 figs.

  1. Field Testing of a Portable Radiation Detector and Mapping System

    SciTech Connect

    Hofstetter, K.J. [Westinghouse Savannah River Company, AIKEN, SC (United States); Hayes, D.W.; Eakle, R.F.

    1998-03-01

    Researchers at the Savannah River Site (SRS) have developed a man- portable radiation detector and mapping system (RADMAPS) which integrates the accumulation of radiation information with precise ground locations. RADMAPS provides field personnel with the ability to detect, locate, and characterize nuclear material at a site or facility by analyzing the gamma or neutron spectra and correlating them with position. the man-portable field unit records gamma or neutron count rate information and its location, along with date and time, using an embedded Global Positioning System (GPS). RADMAPS is an advancement in data fusion, integrating several off-the-shelf technologies with new computer software resulting in a system that is simple to deploy and provides information useful to field personnel in an easily understandable form. Decisions on subsequent actions can be made in the field to efficiently use available field resources. The technologies employed in this system include: recording GPS, radiation detection (typically scintillation detectors), pulse height analysis, analog-to-digital converters, removable solid-state (Flash or SRAM) memory cards, Geographic Information System (GIS) software and personal computers with CD-ROM supporting digital base maps. RADMAPS includes several field deployable data acquisition systems designed to simultaneously record radiation and geographic positions. This paper summarizes the capabilities of RADMAPS and some of the results of field tests performed with the system.

  2. Investigation of radiation doses in open space using TLD detectors.

    PubMed

    Reitz, G; Facius, R; Bilski, P; Olko, P

    2002-01-01

    The low energy component of the cosmic radiation field is strongly modified by the shielding of the spacecraft and it is time and location dependent. Thermoluminescent lithium fluoride detectors have been applied to determine the radiation doses inside the ESA-Facility BIOPAN. The BIOPAN facility was mounted outside and launched on a Foton spacecraft and opened to space to allow exposure of several experiments to open space. Standard TLD-600. TLD-700 chips, two layers MTS-Ns sintered pellets with different effective thickness of the sensitive layer and MTS-N of different thickness have been exposed with different shielding thicknesses in front of them. The measured TL signal in the 0.1 mm thick detector just shielded by an aluminised Kapton foil of 25 microm thickness in front yielded a dose of 29.8 Gy (calibrated with 137Cs gamma rays) for an exposure time of 12.7 days: after 2.5 g.cm(-2) shielding the doses dropped to 3 mGy. The monitoring of radiation doses and its depth dose distribution outside the spacecraft are of great interest for radiation protection of astronauts working in open space. The knowledge of depth-dose distribution is a prerequisite to determine the organ doses an astronaut will receive during an extravehicular activity (EVA). The BIOPAN experiments are to be continued in the future. PMID:12382937

  3. Experimental comparison of discrete and CMOS charge sensitive preamplifiers for CZT radiation detectors

    Microsoft Academic Search

    Guillaume Montémont; Jean-Pierre Rostaing; Loïck Verger

    2003-01-01

    During recent years, many readout integrated circuits for CdZnTe (CZT) radiation detectors have been studied particularly for use on pixellated detectors in imaging applications. The fundamental challenge is to keep noise performance similar to discrete preamplifiers, even with lower power. This paper presents an experimental evaluation of CMOS integrated charge sensitive preamplifiers intended for CZT radiation detectors using a comparison

  4. Reliability aspects of a radiation detector fabricated by post-processing a standard CMOS chip

    Microsoft Academic Search

    Cora Salm; Victor M. Blanco Carballo; Joost Melai; Jurriaan Schmitz

    2008-01-01

    This paper describes various reliability concerns of the newly developed INGRID detector. This radiation detector is fabricated by waferscale CMOS post-processing; fresh detectors show excellent performance. Since the microsystems will be used unpackaged they are susceptible to all kinds of environmental con- ditions. The device passed tests of micro-ESD, radiation hardness, dielectric strength; but humidity tests show one weakness of

  5. The role of the false events on the DQE measurement of the radiation detectors

    E-print Network

    Giovanni Zanella

    2012-11-12

    The efficiency of a radiation detector, intended as probability of detection of an incident quantum, depends on various factors: the detected fraction of quanta ascribed to the noise-less detector, the intrinsic noise of the detector, the false events introduced by the detection process and the false events generated by the detector itself. In this paper is treated the role of the false events on the measurement of the detective quantum efficiency (DQE) of the radiation detectors, indifferently for counting detectors and imaging detectors.

  6. PERDaix -Proton Electron Radiation Detector Aix-la-Chapelle

    NASA Astrophysics Data System (ADS)

    Schug, David; Schael, Stefan; Yearwood Roper, Gregorio; Bachlechner, Andreas; Beischer, Bastian; Deckenhoff, Mirco; Greim, Roman; Jenniches, Laura; Kucirek, Philipp; Lewke, Ronja; Mai, Carsten; Schug, David; Shchutska, Lesya; Tholen, Heiner; Ulrich, Jascha; Wienkenhoever, Jens; Zimmermann, Nikolas

    For the purpose of understanding recent cosmic ray measurements in the energy region below 10 GeV it is important to obtain good knowledge of the charge-sign dependent modulation caused by interplanetary magnetic fields. Existing three-dimensional time-dependent models of the heliosphere can be constrained further using series of measurements of the low-energy cosmic ray fluxes over the course of a solar cycle. Following the measurements of the positron fraction from AESOP in 2006 and 2009, we present a new light-weighted spectrometer which is under construction in Aachen for measuring helium, proton, positron and electron fluxes. The detector is designed to measure in the energy range between 0.5 GeV and 5 GeV and identify helium, protons, electrons and positrons. The detector consists of a spectrometer made up of a permanent magnet and a scintillating fiber tracking detector, a transition radiation detector and a time of flight system with a total weight of approximately 30kg. We applied successfully for a flight on a stratosphere balloon in late 2010 as part of the German-Swedish Balloon-Borne Experiments for University Students (BEXUS) Program.

  7. Cadmium-zinc telluride detector arrays for synchrotron radiation applications

    NASA Astrophysics Data System (ADS)

    Kakuno, Edson M.; Camarda, Giuseppe S.; Siddons, D. P.

    2004-01-01

    We have begun a program to develop CZT-based detectors optimized for Synchrotron Radiation (SR) applications. SR provides high brightness beams of hard x-rays, typically in the range 5-100keV. Below 10keV, Peltier-cooled silicon detector arrays can provide high throughput with good spectroscopic resolution. At higher energies, only cryo-cooled germanium detectors or scintillation counters are available. Neither are easily available in large arrays, and scintillation counters lack energy resolution. CZT offers a solution to both these problems. Our development has focused on surface preparation and contact definition technologies which minimize device leakage currents while allowing high-definition contact patterns suitable for SR applications. We have used SR also for diagnostic purposes in these developments, both for detector testing and material characterization. X-ray diffraction, Infrared microscopy and photoemission are all relevant SR-based tools which we are using in our work. As an example, we have observed that bromine remains attached to the CZT surface after chemical etching, and is remarkably persistent in the face of surface cleaning and argon ion sputtering, as revealed by photoemission spectroscopy and x-ray absorption spectroscopy.

  8. 3D — A proposed new architecture for solid-state radiation detectors

    Microsoft Academic Search

    S. I. Parker; C. J. Kenney; J. Segal

    1997-01-01

    A proposed new architecture for solid-state radiation detectors using a three-dimensional array of electrodes that penetrate into the detector bulk is described. Proposed fabrication steps are listed. Collection distances and calculated collection times are about one order of magnitude less than those of planar technology strip and pixel detectors with electrodes confined to the detector surface, and depletion voltages are

  9. Intrinsic Radiation in Lutetium Based PET Detector: Advantages and Disadvantages

    E-print Network

    Wei, Qingyang

    2015-01-01

    Lutetium (Lu) based scintillators such as LSO and LYSO, are widely used in modern PET detectors due to their high stopping power for 511 keV gamma rays, high light yield and short decay time. However, 2.6% of naturally occurring Lu is 176Lu, a long-lived radioactive element including a beta decay and three major simultaneous gamma decays. This phenomenon introduces random events to PET systems that affects the system performance. On the other hand, the advantages of intrinsic radiation of 176Lu (IRL) continues to be exploited. In this paper, research literatures about IRL in PET detectors are reviewed. Details about the adverse effects of IRL to PET and their solutions, as well as the useful applications are presented and discussed.

  10. On the radiation tolerance of SU8, a new material for gaseous microstructure radiation detector fabrication

    Microsoft Academic Search

    M. J. Key; V. Cindro; M. Lozano

    2004-01-01

    SU-8 photosensitive epoxy resin was developed for the fabrication of high-aspect ratio microstructures in MEMS and microengineering applications, and has potential for use in the construction of novel gaseous micropattern radiation detectors. However, little is known of the behaviour of the cured material under irradiation. Mechanical properties of SU-8 film have been measured as a function of neutron exposure and

  11. Scintillation Detectors for Radiation-Hard Electromagnetic Calorimeters

    NASA Astrophysics Data System (ADS)

    Löhner, H.

    2005-02-01

    For the application in the compact and radiation hard electromagnetic (EM) calorimeter in the PANDA detection system at the new GSI facility, we have started to advance scintillation crystals and the light detection technique. PANDA is the universal internal-target detection system for charmonium spectroscopy and the search for glue-balls and hybrid states in antiproton annihilations. In particular, the large dynamic range from several GeV down to a detection threshold of some MeV for EM radiation and the expected high background rate of neutrons and ions will impose severe requirements on crystals and light sensors. In the magnetic environment of tracking devices the use of Avalanche Photodiodes (APD's) is preferred. In order to achieve suitable resolution for low energy hadrons and photons, the light output of crystals will have to be improved by special production techniques, activation and doping. These procedures might have implications for the radiation hardness. We report on measurements of signal response and radiation damage in crystals of PbWO4 and BGO both from the BTCP (Russia) and SICCAS (China) production sites. Beams of protons, electrons and photons have been applied while detectors with either phototube or APD readout were operated in the range from room temperature to -20°C. Results on light yield and energy resolution are presented. We report on the reduction of light transmission after proton irradiation and results from electron-spin resonance studies on irradiated crystals to analyse the cause of radiation damage.

  12. Measuring the radiation field and radiation hard detectors at JET: Recent developments

    NASA Astrophysics Data System (ADS)

    Murari, A.; Edlington, T.; Angelone, M.; Bertalot, L.; Bolshakova, I.; Bonheure, G.; Brzozowski, J.; Coccorese, V.; Holyaka, R.; Kiptily, V.; Lengar, I.; Morgan, P.; Pillon, M.; Popovichev, S.; Prior, P.; Prokopowicz, R.; Quercia, A.; Rubel, M.; Santala, M.; Shevelev, A.; Syme, B.; Vagliasindi, G.; Villari, R.; Zoita, V. L.; JET-EFDA Contributors

    2008-08-01

    Since in ITER the radiation field will be much more demanding than that of present day devices, research programmes at JET are aimed at developing radiation hard diagnostics and related components. Initially, significant efforts are devoted to determining the radiation field of both the plasma and in the immediate environment with better accuracy. New developments in MCNP calculations and dedicated measurements provide useful information about the radiation field in the Torus Hall, even during non-operational periods. The effect of using Beryllium in the near future for JET first wall, is being assessed. New materials for activation samples are under consideration and will be tested to improve the calibration accuracy of JET neutron diagnostics. The long-term goal of this work is to obtain spectrometric information from an appropriate combination of different materials. Several studies are under way to modify the radiation field at the detectors by using LiH or pure water as neutron filters, to alleviate the problem of the background in ?-ray measurements. A suite of radiation hard detectors for neutrons, magnetic field and charged particles are being developed. Super-heated fluid neutron detectors, used for yield and imaging, are being upgraded, in order to provide a broad-band spectrometric capability. Chemical vapour deposited diamond diodes are being qualified as counters and as spectrometers. Prototypes of Hall probes made of InSb have been installed on the machine and have provided some preliminary results. Si-on-insulator detectors are under development for use in neutral particle analysers and are currently being bench-tested. Some attention is being devoted to optical components, fibres and mirrors, and to investigating radiation hard electronics using reconfigurable Field Programmable Gate Arrays.

  13. IceCube: A Cubic Kilometer Radiation Detector

    SciTech Connect

    IceCube Collaboration; Klein, Spencer R; Klein, S.R.

    2008-06-01

    IceCube is a 1 km{sup 3} neutrino detector now being built at the Amudsen-Scott South Pole Station. It consists of 4800 Digital Optical Modules (DOMs) which detect Cherenkov radiation from the charged particles produced in neutrino interactions. IceCube will observe astrophysical neutrinos with energies above about 100 GeV. IceCube will be able to separate {nu}{sub {mu}}, {nu}{sub t}, and {nu}{sub {tau}} interactions because of their different topologies. IceCube construction is currently 50% complete.

  14. Nuclear Instruments and Methods in Physics Research A 477 (2002) 299303 Radiation hard cryogenic silicon detectors

    E-print Network

    Zavrtanik, Marko

    increase of the depletion voltage. When the radiation fluence approaches 1015 n=cm2 ; standard detectors the radiation hardness of silicon detectors is their operation at cryogenic temperatures. Indeed, it has beenNuclear Instruments and Methods in Physics Research A 477 (2002) 299­303 Radiation hard cryogenic

  15. Particle identification with the ALICE transition radiation detector

    NASA Astrophysics Data System (ADS)

    Pachmayer, Yvonne

    2014-12-01

    The Transition Radiation Detector (TRD) provides particle identification in the ALICE central barrel. In particular, it allows electron identification via the measurement of transition radiation for p > 1 GeV / c, where pions can no longer be rejected sufficiently via specific energy loss in the ALICE Time Projection Chamber. The ALICE TRD is uniquely designed to record the time evolution of the signal, which allows even better electron/pion separation. In addition, the electron identification capability of the TRD can be used on-line to trigger at level 1. The particle identification and its performance in pp, p-Pb and Pb-Pb collisions employing various methods, such as truncated mean signal, one- and two-dimensional likelihood on integrated charge and neural network, will be presented. The measurement of J/? mesons in Pb-Pb collisions is given as a case study to show how well the TRD contributes to physics analyses due to its excellent pion suppression.

  16. High field CdS detector for infrared radiation

    NASA Technical Reports Server (NTRS)

    Tyagi, R. C.; Robertson, J. B.; Boer, K. W.; Hadley, H. C., Jr. (inventors)

    1974-01-01

    An infrared radiation detector including a cadmium sulfide platelet having a cathode formed on one of its ends and an anode formed on its other end is presented. The platelet is suitably doped such that stationary high-field domains are formed adjacent the cathode when based in the negative differential conductivity region. A negative potential is applied to the cathode such that a high-field domain is formed adjacent to the cathode. A potential measuring probe is located between the cathode and the anode at the edge of the high-field domain and means are provided for measuring the potential at the probe whereby this measurement is indicative of the infrared radiation striking the platelet.

  17. From Vacuum Fluctuations to Radiation: Accelerated Detectors and Black Holes

    E-print Network

    S. Massar; R. Parentani

    1994-06-03

    The vacuum fluctuations that induce the transitions and the thermalisation of a uniformly accelerated two level atom are studied in detail. Their energy content is revealed through the weak measurement formalism of Aharonov et al. It is shown that each time the detector makes a transition it radiates a Minkowski photon. The same analysis is then applied to the conversion of vacuum fluctuations into real quanta in the context of black hole radiation. Initially these fluctuations are located around the light like geodesic that shall generate the horizon and carry zero total energy. However upon exiting from the star they break up into two pieces one of which gradually acquires positive energy and becomes a Hawking quantum, the other, its ''partner", ends up in the singularity. As time goes by the vacuum fluctuations generating Hawking quanta have exponentially large energy densities. This implies that back reaction effects are large.

  18. Low Energy Electron Detector for Space Radiation Measurements

    NASA Astrophysics Data System (ADS)

    Hajdas, Wojtek

    Low Energy Electron Detector LEED is a miniature particle monitor for measurements in space. It is based on the MYTHEN Si-microstrip system made at Paul Scherrer Institut PSI for X-ray detection at the Synchrotron Light Source SLS. It was designed in collaboration with the European Space Agency ESA in order to provide a new instrument covering an unexplored energy range of space electrons below few tens of keV. A lack of measurements and realtime data both at low and high energies of particle as well as difficulties in radiation belts modeling are still persisting even after 40 years from their discovery. In particular the low energy electrons, up to few hundred keV are particularly poorly studied. Such electrons can shed a new light on the acceleration and trapping processes and on the dynamics of radiation belts. Measurements of electrons in wide range of energies can provide a link between hot plasma and trapped higher energy particles. The long term observations can probe and verify a coupling between Sun and Earth magnetosphere. On the spacecraft environment side, the electrons with energies of tens of keV can create radiation hazard for on-board instruments, induce spacecraft charging and increase the background in precise X-ray observations. Therefore the requirements put on monitors devoted for above studies are very demanding and often opposing. A special care in construction of LEED - the space version of MYTHEN was optimizing it for very high fluxes and harsh radiation environment. The device aims to monitor Space Weather, map planetary Radiation Belts and study hot plasmas and particle acceleration. It will detect electrons with energies from few up to few hundred keV with energy resolution of several keV. The detector is characterized by ability to deal with very high counting rate of up to 1.4 million counts per second per strip. Its core is a PSI developed radiation hard ASIC read-out chip serving for 128 detection channels. The main design features of LEED are small size and weight as well as minimized power consumption. This makes it also very beneficial for radiation detection at remote locations like peripheries of other planets of the solar system. The LEED demonstration model has been constructed and first qualification measurements with electron beams are being performed. In parallel, the radiation hardness tests of electronic components are prepared at the PSI Proton Irradiation Facility PIF to qualify its critical parts for the flight version. The full computer model of the detector was constructed using GEANT4 package from CERN. It allowed for improvement of the detector response and study background rejection methods. Development of LEED is supported by the Swiss Space Office and ESA. Future possible implementation on-board of the International Space Station and on micro-satellites is currently investigated.

  19. Processing and characterization of epitaxial GaAs radiation detectors

    E-print Network

    Wu, X; Arsenovich, T; Gädda, A; Härkönen, J; Junkes, A; Karadzhinova, A; Kostamo, P; Lipsanen, H; Luukka, P; Mattila, M; Nenonen, S; Riekkinen, T; Tuominen, E; Winkler, A

    2015-01-01

    GaAs devices have relatively high atomic numbers (Z=31, 33) and thus extend the X-ray absorption edge beyond that of Si (Z=14) devices. In this study, radiation detectors were processed on GaAs substrates with 110 $\\mu\\textrm{m}$ - 130 $\\mu\\textrm{m}$ thick epitaxial absorption volume. Thick undoped and heavily doped p$^+$ epitaxial layers were grown using a custom-made horizontal Chloride Vapor Phase Epitaxy (CVPE) reactor, the growth rate of which was about 10 $\\mu\\textrm{m}$/h. The GaAs p$^+$/i/n$^+$ detectors were characterized by Capacitance Voltage ($CV$), Current Voltage ($IV$), Transient Current Technique (TCT) and Deep Level Transient Spectroscopy (DLTS) measurements. The full depletion voltage ($V_{\\textrm{fd}}$) of the detectors with 110 $\\mu\\textrm{m}$ epi-layer thickness is in the range of 8 V - 15 V and the leakage current density is about 10 nA/cm$^2$. The signal transit time determined by TCT is about 5 ns when the bias voltage is well above the value that produces the peak saturation drift ve...

  20. Electrical delay line multiplexing for pulsed mode radiation detectors.

    PubMed

    Vinke, Ruud; Yeom, Jung Yeol; Levin, Craig S

    2015-04-01

    Medical imaging systems are composed of a large number of position sensitive radiation detectors to provide high resolution imaging. For example, whole-body Positron Emission Tomography (PET) systems are typically composed of thousands of scintillation crystal elements, which are coupled to photosensors. Thus, PET systems greatly benefit from methods to reduce the number of data acquisition channels, in order to reduce the system development cost and complexity. In this paper we present an electrical delay line multiplexing scheme that can significantly reduce the number of readout channels, while preserving the signal integrity required for good time resolution performance. We experimented with two 4 × 4 LYSO crystal arrays, with crystal elements having 3 mm × 3 mm × 5 mm and 3 mm × 3 mm × 20 mm dimensions, coupled to 16 Hamamatsu MPPC S10931-050P SiPM elements. Results show that each crystal could be accurately identified, even in the presence of scintillation light sharing and inter-crystal Compton scatter among neighboring crystal elements. The multiplexing configuration degraded the coincidence timing resolution from ?243 ps FWHM to ?272 ps FWHM when 16 SiPM signals were combined into a single channel for the 4 × 4 LYSO crystal array with 3 mm × 3 mm × 20 mm crystal element dimensions, in coincidence with a 3 mm × 3 mm × 5 mm LYSO crystal pixel. The method is flexible to allow multiplexing configurations across different block detectors, and is scalable to an entire ring of detectors. PMID:25768002

  1. Ambient temperature cadmium zinc telluride radiation detector and amplifier circuit

    DOEpatents

    McQuaid, J.H.; Lavietes, A.D.

    1998-05-26

    A low noise, low power consumption, compact, ambient temperature signal amplifier for a Cadmium Zinc Telluride (CZT) radiation detector is disclosed. The amplifier can be used within a larger system (e.g., including a multi-channel analyzer) to allow isotopic analysis of radionuclides in the field. In one embodiment, the circuit stages of the low power, low noise amplifier are constructed using integrated circuit (IC) amplifiers , rather than discrete components, and include a very low noise, high gain, high bandwidth dual part preamplification stage, an amplification stage, and an filter stage. The low noise, low power consumption, compact, ambient temperature amplifier enables the CZT detector to achieve both the efficiency required to determine the presence of radionuclides and the resolution necessary to perform isotopic analysis to perform nuclear material identification. The present low noise, low power, compact, ambient temperature amplifier enables a CZT detector to achieve resolution of less than 3% full width at half maximum at 122 keV for a Cobalt-57 isotope source. By using IC circuits and using only a single 12 volt supply and ground, the novel amplifier provides significant power savings and is well suited for prolonged portable in-field use and does not require heavy, bulky power supply components. 9 figs.

  2. Electrical delay line multiplexing for pulsed mode radiation detectors

    NASA Astrophysics Data System (ADS)

    Vinke, Ruud; Yeom, Jung Yeol; Levin, Craig S.

    2015-04-01

    Medical imaging systems are composed of a large number of position sensitive radiation detectors to provide high resolution imaging. For example, whole-body Positron Emission Tomography (PET) systems are typically composed of thousands of scintillation crystal elements, which are coupled to photosensors. Thus, PET systems greatly benefit from methods to reduce the number of data acquisition channels, in order to reduce the system development cost and complexity. In this paper we present an electrical delay line multiplexing scheme that can significantly reduce the number of readout channels, while preserving the signal integrity required for good time resolution performance. We experimented with two 4 × 4 LYSO crystal arrays, with crystal elements having 3 mm × 3 mm × 5 mm and 3 mm × 3 mm × 20 mm dimensions, coupled to 16 Hamamatsu MPPC S10931-050P SiPM elements. Results show that each crystal could be accurately identified, even in the presence of scintillation light sharing and inter-crystal Compton scatter among neighboring crystal elements. The multiplexing configuration degraded the coincidence timing resolution from ?243 ps FWHM to ?272 ps FWHM when 16 SiPM signals were combined into a single channel for the 4 × 4 LYSO crystal array with 3 mm × 3 mm × 20 mm crystal element dimensions, in coincidence with a 3 mm × 3 mm × 5 mm LYSO crystal pixel. The method is flexible to allow multiplexing configurations across different block detectors, and is scalable to an entire ring of detectors.

  3. Methodology for Assessing Radiation Detectors Used by Emergency Responders

    SciTech Connect

    Piotr Wasiolek; April Simpson

    2008-03-01

    The threat of weapons of mass destruction terrorism resulted in the U.S. Department of Homeland Security deploying large quantities of radiation detectors throughout the emergency responder community. However, emergency responders specific needs were not always met by standard health physics instrumentation used in radiation facilities. Several American National Standards Institute standards were developed and approved to evaluate the technical capabilities of detection equipment. Establishing technical capability is a critical step, but it is equally important to emergency responders that the instruments are easy to operate and can withstand the rugged situations they encounter. The System Assessment and Validation for Emergency Responders (SAVER) Program (managed by the U.S. Department of Homeland Security, Office of Grants and Training, Systems Support Division) focuses predominantly on the usability, ergonomics, readability, and other features of the detectors, rather than performance controlled by industry standards and the manufacturers. National Security Technologies, LLC, as a SAVER Technical Agent, conducts equipment evaluations using active emergency responders who are familiar with the detection equipment and knowledgeable of situations encountered in the field, which provides more relevant data to emergency responders.

  4. Single charge carrier type sensing with a parallel strip pseudo-Frisch-grid CdZnTe semiconductor radiation detector

    E-print Network

    He, Zhong

    radiation detector D. S. McGregor,a) Z. He, H. A. Seifert, and D. K. Wehe Department of Nuclear Engineering temperature operated ra- diation detectors. The most common semiconductor radiation detector design CdZnTe semiconductor detector that incorporates a parallel strip pseudo-Frisch-grid detector design

  5. Radiation Hard Hybrid Pixel Detectors, and a bbbar Cross Section Measurement at the CMS Experiment

    E-print Network

    Sibille, Jennifer Ann

    2013-05-31

    is placed on the effects of the high radiation environment on the detector operation. Measurements of the charge collection efficiency, interpixel capacitance, and other properties of the pixel sensors as a function of the radiation damage are presented...

  6. Charged Particle Measurements with the Radiation Assessment Detector on Board the Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Ehresmann, B.; Hassler, D. M.; Zeitlin, C.; Wimmer-Schweingruber, R. F.; Koehler, J.; Appel, J. K.; Boehm, E.; Boettcher, S.; Brinza, D. E.; Burmeister, S.; Guo, J.; Lohf, H.; Martin, C.; Posner, A.; Rafkin, S.; Reitz, G.

    2014-07-01

    The Radiation Assessment Detector (RAD) on board the MSL Curiosity rover is conducting the first-ever radiation measurements on the martian surface. Here, we present measurement results of charged particle fluxes and their temporal evolution.

  7. Field Deployable Gamma Radiation Detectors for DHS Use

    SciTech Connect

    Sanjoy Mukhopadhyay

    2007-08-31

    Recently, the U.S. Department of Homeland Security (DHS) has integrated all nuclear detection research, development, testing, evaluation, acquisition, and operational support into a single office: the Domestic Nuclear Detection Office (DNDO). The DNDO has specific requirements set for all commercial and government off-the-shelf radiation detection equipment and data acquisition systems. This article would investigate several recent developments in field deployable gamma radiation detectors that are attempting to meet the DNDO specifications. Commercially available, transportable, handheld radio isotope identification devices (RIID) are inadequate for DHS’s requirements in terms of sensitivity, resolution, response time and reach back capability. The leading commercial vendor manufacturing handheld gamma spectrometer in the United States is Thermo Electron Corporation. Thermo Electron’s identiFINDER™, which primarily uses sodium iodide crystals (3.18-cm x 2.54-cm cylinders) as gamma detector, has a Full-Width-at-Half-Maximum energy resolution of 7 percent at 662 keV. Thermo Electron has just recently come up with a reach-back capability patented as RadReachBack™ that enables emergency personnel to obtain real-time technical analysis of radiation samples they find in the field. The current project has the goal to build a prototype handheld gamma spectrometer, equipped with a digital camera and an embedded cell phone to be used as an RIID with higher sensitivity (comparable to that of a 7.62-cm x 7.62-cm sodium iodide crystal at low gamma energy ranging from 30 keV to 3,000 keV), better resolution (< 3.0 percent at 662 keV), faster response time (able to detect the presence of gamma-emitting radio isotopes within 5 seconds of approach), which will make it useful as a field deployable tool. The handheld equipment continuously monitors the ambient gamma radiation and, if it comes across any radiation anomalies with higher than normal gamma gross counts, it sets an alarm condition. When a substantial alarm level is reached, the system auto triggers saving of relevant spectral data and software-triggers the digital camera to take a snapshot. The spectral data including in situ analysis and the imagery data will be packaged in a suitable format and sent to a command post using an imbedded cell phone.

  8. Examination system utilizing ionizing radiation and a flexible, miniature radiation detector probe

    DOEpatents

    Majewski, Stanislaw (Grafton, VA); Kross, Brian J. (Yorktown, VA); Zorn, Carl J. (Yorktown, VA); Majewski, Lukasz A. (Grafton, VA)

    1996-01-01

    An optimized examination system and method based on the Reverse Geometry X-Ray.RTM. (RGX.RTM.) radiography technique are presented. The examination system comprises a radiation source, at least one flexible, miniature radiation detector probe positioned in appropriate proximity to the object to be examined and to the radiation source with the object located between the source and the probe, a photodetector device attachable to an end of the miniature radiation probe, and a control unit integrated with a display device connected to the photodetector device. The miniature radiation detector probe comprises a scintillation element, a flexible light guide having a first end optically coupled to the scintillation element and having a second end attachable to the photodetector device, and an opaque, environmentally-resistant sheath surrounding the flexible light guide. The probe may be portable and insertable, or may be fixed in place within the object to be examined. An enclosed, flexible, liquid light guide is also presented, which comprises a thin-walled flexible tube, a liquid, preferably mineral oil, contained within the tube, a scintillation element located at a first end of the tube, closures located at both ends of the tube, and an opaque, environmentally-resistant sheath surrounding the flexible tube. The examination system and method have applications in non-destructive material testing for voids, cracks, and corrosion, and may be used in areas containing hazardous materials. In addition, the system and method have applications for medical and dental imaging.

  9. Examination system utilizing ionizing radiation and a flexible, miniature radiation detector probe

    DOEpatents

    Majewski, S.; Kross, B.J.; Zorn, C.J.; Majewski, L.A.

    1996-10-22

    An optimized examination system and method based on the Reverse Geometry X-Ray{trademark} (RGX{trademark}) radiography technique are presented. The examination system comprises a radiation source, at least one flexible, miniature radiation detector probe positioned in appropriate proximity to the object to be examined and to the radiation source with the object located between the source and the probe, a photodetector device attachable to an end of the miniature radiation probe, and a control unit integrated with a display device connected to the photodetector device. The miniature radiation detector probe comprises a scintillation element, a flexible light guide having a first end optically coupled to the scintillation element and having a second end attachable to the photodetector device, and an opaque, environmentally-resistant sheath surrounding the flexible light guide. The probe may be portable and insertable, or may be fixed in place within the object to be examined. An enclosed, flexible, liquid light guide is also presented, which comprises a thin-walled flexible tube, a liquid, preferably mineral oil, contained within the tube, a scintillation element located at a first end of the tube, closures located at both ends of the tube, and an opaque, environmentally-resistant sheath surrounding the flexible tube. The examination system and method have applications in non-destructive material testing for voids, cracks, and corrosion, and may be used in areas containing hazardous materials. In addition, the system and method have applications for medical and dental imaging. 5 figs.

  10. Personal Radiation Detector Field Test and Evaluation Campaign

    SciTech Connect

    Chris A. Hodge, Ding Yuan, Raymond P. Keegan, Michael A. Krstich

    2007-07-09

    Following the success of the Anole test of portable detection system, the U.S. Department of Homeland Security (DHS) Domestic Nuclear Detection Office organized a test and evaluation campaign for personal radiation detectors (PRDs), also known as 'Pagers'. This test, 'Bobcat', was conducted from July 17 to August 8, 2006, at the Nevada Test Site. The Bobcat test was designed to evaluate the performance of PRDs under various operational scenarios, such as pedestrian surveying, mobile surveying, cargo container screening, and pedestrian chokepoint monitoring. Under these testing scenarios, many operational characteristics of the PRDs, such as gamma and neutron sensitivities, positive detection and false alarm rates, response delay times, minimum detectable activities, and source localization errors, were analyzed. This paper will present the design, execution, and methodologies used to test this equipment for the DHS.

  11. A general purpose multichannel readout system for radiation detectors

    NASA Astrophysics Data System (ADS)

    Kulis, S.; Matoga, A.; Idzik, M.; Swientek, K.; Fiutowski, T.; Przyborowski, D.

    2012-01-01

    The design and performance of a multichannel readout system for radiation detectors are presented. The developed 32-channel prototype system comprises fast, low-noise, front-end followed by a 10-bit multichannel digitizer and on-board FPGA data concentrator, processing the stream of digitized data with up to 6.4 Gbps rate. The operation of the whole system is managed by a microcontroller. The system can work in self-triggering mode or can be triggered externally. The implemented trigger mechanism allows for elaborate event filtering and selection of data to be transmitted to the host through the USB interface. A wide spectrum of measurements showing and quantifying the key system parameters like data transmission rate and event rate, noise, and gain are presented to prove the correct system performance. To increase the power efficiency in experiments with a non-continuous beam structure, a power pulsing mechanism is implemented and verified experimentally.

  12. BOBCAT Personal Radiation Detector Field Test and Evaluation Campaign

    SciTech Connect

    Chris Hodge

    2008-03-01

    Following the success of the Anole test of portable detection system, the U.S. Department of Homeland Security (DHS) Domestic Nuclear Detection Office organized a test and evaluation campaign for personal radiation detectors (PRDs), also known as “Pagers.” This test, “Bobcat,” was conducted from July 17 to August 8, 2006, at the Nevada Test Site. The Bobcat test was designed to evaluate the performance of PRDs under various operational scenarios, such as pedestrian surveying, mobile surveying, cargo container screening, and pedestrian chokepoint monitoring. Under these testing scenarios, many operational characteristics of the PRDs, such as gamma and neutron sensitivities, positive detection and false alarm rates, response delay times, minimum detectable activities, and source localization errors, were analyzed. This paper will present the design, execution, and methodologies used to test this equipment for the DHS.

  13. Multiple cell radiation detector system, and method, and submersible sonde

    DOEpatents

    Johnson, Larry O. (Island Park, ID); McIsaac, Charles V. (Idaho Falls, ID); Lawrence, Robert S. (Shelley, ID); Grafwallner, Ervin G. (Arco, ID)

    2002-01-01

    A multiple cell radiation detector includes a central cell having a first cylindrical wall providing a stopping power less than an upper threshold; an anode wire suspended along a cylindrical axis of the central cell; a second cell having a second cylindrical wall providing a stopping power greater than a lower threshold, the second cylindrical wall being mounted coaxially outside of the first cylindrical wall; a first end cap forming a gas-tight seal at first ends of the first and second cylindrical walls; a second end cap forming a gas-tight seal at second ends of the first and second cylindrical walls; and a first group of anode wires suspended between the first and second cylindrical walls.

  14. Electrically calibrated pyroelectric detector for high-accuracy calibration of UV radiation

    Microsoft Academic Search

    Xiumei Shao; Jieying Ding; Yuehua Yu; Jiaxiong Fang

    2008-01-01

    A pyroelectric detector with special structure was developed for calibration of UV radiation. A new relaxor-based ferroelectric single crystal with high pyroelectric coefficient was selected as the detector material. The detector is free of substrate and a black coating film was deposited on the surface of the sensitive area. The reflectance of the coating film is less than 1% in

  15. Multielement silicon detectors for registration of charged particles, x-rays and gamma-radiation

    Microsoft Academic Search

    D. O. Frolov; O. S. Frolov; A. A. Sadovnichiy; O. F. Nimets; V. A. Shevchenko

    2001-01-01

    A novel type multi-sectional detector consisting of separate sections has been developed. Signals from each section pass through a shaping amplifier channel and then are mixed in a special manner. This principle allows reduction of detector's and amplifier's electrical noise in many times, and due to this allows one to develop detectors and spectrometers for various types of radiation with

  16. Study of multi-electrodes structure in CdTe nuclear radiation detectors

    Microsoft Academic Search

    Madan Niraula; Yasunori Agata; Kazuhito Yasuda

    2004-01-01

    We studied CdTe nuclear radiation detectors with multi-electrodes structure. The detector consists of a common cathode, while the anode has been separated into three electrodes: the central collecting anode, a guard ring electrode, and a guiding electrode. The detector was biased in such a way that the central anode collects electrons while the guiding electrode repel electrons and guide them

  17. AN EVALUATION OF CADMIUM SULFIDE AS A NUCLEAR RADIATION DETECTOR (thesis)

    Microsoft Academic Search

    1962-01-01

    Solid state radiation detectors were constructed using crystal platelets ; of CdS. Both intrinsic and p-n junction detectors were made and evaluated. ; Although alpha particles were detected by both types of detectors, the mobility-; lifetime product of the charge carriers resulted in the pulse response not being ; proportional to the energy of the incident particle. The best experimental

  18. Gas mixtures for gas-filled radiation detectors

    DOEpatents

    Christophorou, Loucas G. (Oak Ridge, TN); McCorkle, Dennis L. (Knoxville, TN); Maxey, David V. (Knoxville, TN); Carter, James G. (Knoxville, TN)

    1982-01-05

    Improved binary and ternary gas mixtures for gas-filled radiation detectors are provided. The components are chosen on the basis of the principle that the first component is one molecular gas or mixture of two molecular gases having a large electron scattering cross section at energies of about 0.5 eV and higher, and the second component is a noble gas having a very small cross section at and below about 1.0 eV, whereby fast electrons in the gaseous mixture are slowed into the energy range of about 0.5 eV where the cross section for the mixture is small and hence the electron mean free path is large. The reduction in both the cross section and the electron energy results in an increase in the drift velocity of the electrons in the gas mixtures over that for the separate components for a range of E/P (pressure-reduced electric field) values. Several gas mixtures are provided that provide faster response in gas-filled detectors for convenient E/P ranges as compared with conventional gas mixtures.

  19. Improved gas mixtures for gas-filled radiation detectors

    DOEpatents

    Christophorou, L.G.; McCorkle, D.L.; Maxey, D.V.; Carter, J.G.

    1980-03-28

    Improved binary and ternary gas mixtures for gas-filled radiation detectors are provided. The components are chosen on the basis of the principle that the first component is one molecular gas or mixture of two molecular gases having a large electron scattering cross section at energies of about 0.5 eV and higher, and the second component is a noble gas having a very small cross section at and below about 1.0 eV, whereby fast electrons in the gaseous mixture are slowed into the energy range of about 0.5 eV where the cross section for the mixture is small and hence the electron mean free path is large. The reduction in both the cross section and the electron energy results in an increase in the drift velocity of the electrons in the gas mixtures over that for the separate components for a range of E/P (pressure-reduced electric field) values. Several gas mixtures are provided that provide faster response in gas-filled detectors for convenient E/P ranges as compared with conventional gas mixtures.

  20. Seismic restraint means for a nuclear radiation detector mounted in a tubular thimble

    Microsoft Academic Search

    R. H. Underwood; W. H. Todt

    1985-01-01

    Seismic restraint means are provided for mounting an elongated, generally cylindrical nuclear radiation detector within a tubular thimble. The restraint means permits longitudinal movement of the restraint means and the radiation detector into and out of the thimble. The restraint means includes spring bias means and thimble constant means whereby the contact means engage the thimble with a constant predetermined

  1. Wire-chamber radiation detector with discharge control

    DOEpatents

    Perez-Mendez, V.; Mulera, T.A.

    1982-03-29

    A wire chamber; radiation detector has spaced apart parallel electrodes and grids defining an ignition region in which charged particles or other ionizing radiations initiate brief localized avalanche discharges and defining an adjacent memory region in which sustained glow discharges are initiated by the primary discharges. Conductors of the grids at each side of the memory section extend in orthogonal directions enabling readout of the X-Y coordinates of locations at which charged particles were detected by sequentially transmitting pulses to the conductors of one grid while detecting transmissions of the pulses to the orthogonal conductors of the other grid through glow discharges. One of the grids bounding the memory region is defined by an array of conductive elements each of which is connected to the associated readout conductor through a separate resistance. The wire chamber avoids ambiguities and imprecisions in the readout of coordinates when large numbers of simultaneous or; near simultaneous charged particles have been detected. Down time between detection periods and the generation of radio frequency noise are also reduced.

  2. Particle Identification with the ALICE Transition Radiation Detector

    E-print Network

    Yvonne Pachmayer for the ALICE Collaboration

    2014-02-14

    The Transition Radiation Detector (TRD) provides particle identification in the ALICE central barrel. In particular, it allows electron identification via the measurement of transition radiation for $\\rm p >$ 1 GeV/$c$, where pions can no longer be rejected sufficiently via specific energy loss in the ALICE Time Projection Chamber. The ALICE TRD is uniquely designed to record the time evolution of the signal, which allows even better electron/pion separation. In addition, the electron identification capability of the TRD can be used on-line to trigger at level 1. The particle identification and its performance in pp, p-Pb and Pb-Pb collisions employing various methods, such as truncated mean signal, one- and two-dimensional likelihood on integrated charge and neural network, will be presented. The measurement of J/$\\psi$ mesons in Pb-Pb collisions is given as a case study to show how well the TRD contributes to physics analyses due to its excellent pion suppression.

  3. Method and system for determining depth distribution of radiation-emitting material located in a source medium and radiation detector system for use therein

    DOEpatents

    Benke, Roland R.; Kearfott, Kimberlee J.; McGregor, Douglas S.

    2004-04-27

    A radiation detector system includes detectors having different properties (sensitivity, energy resolution) which are combined so that excellent spectral information may be obtained along with good determinations of the radiation field as a function of position.

  4. Development of CdTe nuclear radiation detectors for spectroscopy and imaging applications

    Microsoft Academic Search

    M. Niraula; K. Yasuda; Y. Agata; A. Nakamura; T. Aoki; Y. Hatanaka

    2003-01-01

    CdTe nuclear radiation detectors were developed for spectroscopy and imaging applications. Detectors were fabricated in two different techniques in order to alleviate the poor hole charge transport property in CdTe semiconductor. The first type comprises an M-?-n diode type detector fabricated by growing an n-type CdTe epitaxial layer on the p-like high resistivity CdTe crystal wafer. This detector is operated

  5. Gallium Arsenide Radiation Detectors for the ATLAS Experiment

    E-print Network

    Glasgow, University of

    detector. The pad detector was used to investigate the electrical and charge collection characteristics of the device both before and after neutron and charged particle irradiation. The microstrip detectors enabled of ¸ 1 ¯m/V. The charge collection of the SI­U detectors were measured to be less than 100% due

  6. SEMICONDUCTOR NUCLEAR-RADIATION DETECTORS. SILICON JUNCTION DETECTORS OF GOOD RESOLUTION, LONG-TERM STABILITY AND FAST RISE TIME SUITABLE FOR NUCLEAR RESEARCH

    Microsoft Academic Search

    J. Terada; Y. Ebara; J. Yoshida; T. Kobayashi

    1963-01-01

    Characteristics of the silicon junction detector and some examples of ; its applications to radiation detection are described. The range of effective ; detection was improved and its application to BETA and gamma measurements was ; expanded. Work was carried out toward the development of a series of radiation ; detectors including a lithium-ion drifted silicon (germanium) detector. (auth);

  7. Cross-Fertilization between Spallation Neutron Source and Third Generation Synchrotron Radiation Detectors

    SciTech Connect

    Gebauer, B.; Schulz, Ch.; Alimov, S.S.; Wilpert, Th. [Hahn-Meitner-Instiut Berlin, Glienicker Str. 100, 14109 Berlin (Germany); Levchanovsky, F.V. [Hahn-Meitner-Instiut Berlin, Glienicker Str. 100, 14109 Berlin (Germany); Frank Laboratory of Neutron Physics, Joint Institute of Nuclear Research, 141980 Dubna (Russian Federation); Litvinenko, E.I.; Nikiforov, A.S. [Frank Laboratory of Neutron Physics, Joint Institute of Nuclear Research, 141980 Dubna (Russian Federation)

    2004-05-12

    Suffering presently from relatively low source strengths compared to synchrotron radiation investigations, neutron scattering methods will greatly benefit from the increase of instantaneous flux attained at the next generation of pulsed spallation neutron sources. In particular at ESS, the strongest projected source, the counting rate load on the detectors will rise by factors of up to 50-150 in comparison with present generic instruments. For these sources the detector requirements overlap partly with those for modern synchrotron radiation detectors as far as counting rate capability and two-dimensional position resolution are concerned. In this paper, examples of the current and forthcoming detector development, comprising e.g. novel solutions for low-pressure micro-strip gas chamber detectors, for silicon micro-strip detectors and for the related front-end ASICs and data acquisition (DAQ) systems, are summarized, which will be of interest for detection of synchrotron radiation as well.

  8. Radiation damage effects by 25 MeV protons and thermal annealing effects on thallium bromide nuclear radiation detectors

    Microsoft Academic Search

    K. Hitomi; T. Shoji; T. Suehiro; Y. Hiratate

    1999-01-01

    In this study, TlBr detectors were irradiated with 25 MeV protons accelerated by an AVF cyclotron. Isothermal annealing was performed to restore the performance of the detectors. In order to characterize the radiation damage and thermal annealing effects on the TlBr detectors, we measured current-voltage (I-V) characteristics, mobility-lifetime (??) products and spectrometric responses. The I-V and ?? measurements suggest that

  9. Performance of an LPD prototype detector at MHz frame rates under Synchrotron and FEL radiation

    NASA Astrophysics Data System (ADS)

    Koch, A.; Hart, M.; Nicholls, T.; Angelsen, C.; Coughlan, J.; French, M.; Hauf, S.; Kuster, M.; Sztuk-Dambietz, J.; Turcato, M.; Carini, G. A.; Chollet, M.; Herrmann, S. C.; Lemke, H. T.; Nelson, S.; Song, S.; Weaver, M.; Zhu, D.; Meents, A.; Fischer, P.

    2013-11-01

    A MHz frame rate X-ray area detector (LPD — Large Pixel Detector) is under development by the Rutherford Appleton Laboratory for the European XFEL. The detector will have 1 million pixels and allows analogue storage of 512 images taken at 4.5 MHz in the detector front end. The LPD detector has 500 ?m thick silicon sensor tiles that are bump bonded to a readout ASIC. The ASIC's preamplifier provides relatively low noise at high speed which results in a high dynamic range of 105 photons over an energy range of 5-20 keV. Small scale prototypes of 32 × 256 pixels (LPD 2-Tile detector) and 256 × 256 pixels (LPD supermodule detector) are now available for X-ray tests. The performance of prototypes of the detector is reported for first tests under synchrotron radiation (PETRA III at DESY) and Free-Electron-Laser radiation (LCLS at SLAC). The initial performance of the detector in terms of signal range and noise, radiation hardness and spatial and temporal response are reported. The main result is that the 4.5 MHz sampling detection chain is reliably working, including the analogue on-chip memory concept. The detector is at least radiation hard up to 5 MGy at 12 keV. In addition the multiple gain concept has been demonstrated over a dynamic range to 104 at 12 keV with a readout noise equivalent to < 1 photon rms in its most sensitive mode.

  10. Plural-wavelength flame detector that discriminates between direct and reflected radiation

    NASA Technical Reports Server (NTRS)

    Hall, Gregory H. (Inventor); Barnes, Heidi L. (Inventor); Medelius, Pedro J. (Inventor); Simpson, Howard J. (Inventor); Smith, Harvey S. (Inventor)

    1997-01-01

    A flame detector employs a plurality of wavelength selective radiation detectors and a digital signal processor programmed to analyze each of the detector signals, and determine whether radiation is received directly from a small flame source that warrants generation of an alarm. The processor's algorithm employs a normalized cross-correlation analysis of the detector signals to discriminate between radiation received directly from a flame and radiation received from a reflection of a flame to insure that reflections will not trigger an alarm. In addition, the algorithm employs a Fast Fourier Transform (FFT) frequency spectrum analysis of one of the detector signals to discriminate between flames of different sizes. In a specific application, the detector incorporates two infrared (IR) detectors and one ultraviolet (UV) detector for discriminating between a directly sensed small hydrogen flame, and reflections from a large hydrogen flame. The signals generated by each of the detectors are sampled and digitized for analysis by the digital signal processor, preferably 250 times a second. A sliding time window of approximately 30 seconds of detector data is created using FIFO memories.

  11. Nuclear Instruments and Methods in Physics Research A 565 (2006) 650656 Semiconductor high-energy radiation scintillation detector

    E-print Network

    Luryi, Serge

    -energy radiation scintillation detector A. Kastalskya , S. Luryia,�, B. Spivakb a University at Stony Brook, ECE scintillation-type detector in which high-energy radiation generates electron­hole pairs in a direct semiconductor scintillator combines the best properties of currently existing radiation detectors and can

  12. X-ray diffuse scattering for evaluation of wide bandgap semiconductor nuclear radiation detectors

    NASA Astrophysics Data System (ADS)

    Goorsky, M. S.; Yoon, H.; Schieber, M.; James, R. B.; McGregor, D. S.; Natarajan, M.

    The crystalline perfection of solid state radiation detectors was examined using triple axis x-ray diffraction. Triple axis techniques provide a means to analyze the origin of diffraction peak broadening: the effects of strain (due to deviations in alloy composition or stoichiometry) and lattice tilts (mosaic structure) can be separated. Cd 1 - xZn xTe ( x ? 0.1), HgI 2, and GaAs detector materials were studied. In the cases of Cd 1 - xZn xTe and HgI 2 the crystalline properties of detectors with different spectral responses to ?-radiation were determined. Increased mosaicity was universally found to be related to deteriorated detector properties. For Cd 1 - xZn xTe, detectors with poor performance possessed greater levels of diffuse scatter due to lattice tilts than did high quality detectors. For GaAs, low angle grain boundaries were attributed to impaired detector performance. Additionally, in large HgI 2 detectors, deviations from stoichiometry were also related to reduced performance. Interestingly, HgI 2 detectors which possessed a sharp spectral response to ?-radiation but also showed polarization were of comparable crystallinity to those detectors which did not exhibit polarization effects. This initial analysis suggests that polarization is related to native point defects or chemical impurities which do not significantly alter the crystallinity of the material. Overall, within a given class of materials, improved detector performance (better spectral response) always correlated with better material quality.

  13. Temperature dependence of radiation damage and its annealing in silicon detectors

    SciTech Connect

    Ziock, H.J.; Boissevain, J.G.; Holzscheiter, K.; Kapustinsky, J.S.; Palounek, A.P.T.; Sondheim, W.E. (Los Alamos National Lab., NM (United States)); Barberis, E.; Cartiglia, N.; Leslie, J.; Pitzl, D.; Rowe, W.A.; Sadrozinski, H.F.W.; Seiden, A.; Spencer, E.; Wilder, M. (Univ. of California, Santa Cruz, CA (United States). Santa Cruz Inst. for Particle Physics); Ellison, J.A.; Fleming, J.K.; Jerger, S.; Joyce, D.; Lietzke, C.; Reed, E.; Wimpenny, S.J. (Univ. of California, Riverside, CA (United States)); Ferguson, P. (Univ. of Missouri, Rolla, MO (United States)); Frautschi, M.A.; Matthews, J.A.J.; Skinner, D. (Univ. of New Mexico, Albuquerque, NM (United States))

    1993-08-01

    The radiation damage resulting from the large particle fluences predicted at the Superconducting Super Collider will induce significant leakage currents in silicon detectors. In order to limit those currents, the authors plan to operate the detectors at reduced temperatures ([approximately] 0 C). In this paper, they present the results of a study of temperature effects on both the initial radiation damage and the long-term annealing of that damage in silicon PIN detectors. Depletion voltage results are reported. The detectors were exposed to approximately 10[sup 14]/cm[sup 2] 650 MeV protons. Very pronounced temperature dependencies were observed.

  14. A liquid radiation detector with high spatial resolution

    NASA Technical Reports Server (NTRS)

    Alvarez, L.

    1972-01-01

    Detector, using point anode, minimizes problem of oblique tracks by permitting construction of very thin counter. Detector is useful in cosmic ray and high energy physics research and X-ray and neutron diffraction technology.

  15. The effects of large signals on charge collection in radiation detectors: Application to amorphous selenium detectors

    NASA Astrophysics Data System (ADS)

    Kabir, M. Zahangir; Emelianova, E. V.; Arkhipov, V. I.; Yunus, M.; Kasap, S. O.; Adriaenssens, G.

    2006-06-01

    Analytical and numerical models for studying the effects of large signals on charge collection efficiency in radiation detectors are described by considering bimolecular recombination between drifting charge carriers, carrier trapping, and space charge effects. First, an analytical solution is obtained by assuming that the field remains relatively uniform. Then the continuity equations for both holes and electrons, and Poisson's equation across the photoconductor for a short pulse irradiation are simultaneously solved by the finite difference method, without any assumptions. There is a very good agreement between the approximate analytical and numerical solutions for the charge collection efficiency. The numerical results are also compared with Monte Carlo simulations of carrier transport. The charge collection efficiency model is applied to amorphous selenium x-ray image detectors. The bimolecular-recombination-limited charge collection efficiency depends on the total photogenerated carrier density rather than on its spatial distribution. It is found that the recombination plays practically no role up to the total instantaneous carrier generation Q0 of 109 EHPs/cm2 at the applied electric field of 10 V/?m. The effect of recombination on charge collection increases with decreasing applied electric field strength. For high carrier generation (e.g., Q0 of 1012 EHPs/cm2 for an applied field of 10 V/?m), the electric field distributions vary widely across the photoconductor thickness during the travel of charge carriers towards the electrodes. However, the effect of bimolecular recombination on charge collection efficiency is almost independent of bias polarity and the field distribution. The numerical results are also compared with recent experimental data available in the literature.

  16. Radiation induced polarization in CdTe detectors

    Microsoft Academic Search

    D. Vartsky; M. Goldberg; Y. Eisen; Y. Shamai; R. Dukhan; P. Siffert; J. M. Koebel; R. Regal; J. Gerber

    1988-01-01

    Polarization induced by irradiation with intense gamma ray sources has been studied in chlorine-compensated CdTe detectors. The influence of several parameters, such as applied field strength, temperature and incident photon flux, on the polarization effect have been investigated. A relationship was found between the degree of polarization, detector efficiency and detector leakage current.

  17. Charged Particle Induced Radiation damage of Germanium Detectors in Space: Two Mars Observer Gamma-Ray Detectors

    NASA Technical Reports Server (NTRS)

    Bruekner, J.; Koenen, M.; Evans, L. G.; Starr, R.; Bailey, S. H.; Boynton W. V.

    1997-01-01

    The Mars Observer Gamma-Ray Spectrometer (MO GRS) was designed to measure gamma-rays emitted by the Martian surface. This gamma-ray emission is induced by energetic cosmic-ray particles penetrating the Martian surface and producing many secondary particles and gamma rays. The MO GRS consisted of an high-purity germanium (HPGe) detector with a passive cooler. Since radiation damage due to permanent bombardment of energetic cosmic ray particles (with energies up to several GeV) was expected for the MO GRS HPGe crystal, studies on radiation damage effects of HPGe crystals were carried on earth. One of the HPGe crystals (paradoxically called FLIGHT) was similar to the MO GRS crystal. Both detectors, MO GRS and FLIGHT, contained closed-end coaxial n-type HPGe crystals and had the same geometrical dimensions (5.6 x 5.6 cm). Many other parameters, such as HV and operation temperature, differed in space and on earth, which made it somewhat difficult to directly compare the performance of both detector systems. But among other detectors, detector FLIGHT provided many useful data to better understand radiation damage effects.

  18. Accelerated Detector - Quantum Field Correlations: From Vacuum Fluctuations to Radiation Flux

    E-print Network

    Shih-Yuin Lin; B. L. Hu

    2006-06-21

    In this paper we analyze the interaction of a uniformly accelerated detector with a quantum field in (3+1)D spacetime, aiming at the issue of how kinematics can render vacuum fluctuations the appearance of thermal radiance in the detector (Unruh effect) and how they engender flux of radiation for observers afar. Two basic questions are addressed in this study: a) How are vacuum fluctuations related to the emitted radiation? b) Is there emitted radiation with energy flux in the Unruh effect? We adopt a method which places the detector and the field on an equal footing and derive the two-point correlation functions of the detector and of the field separately with full account of their interplay. From the exact solutions, we are able to study the complete process from the initial transient to the final steady state, keeping track of all activities they engage in and the physical effects manifested. We derive a quantum radiation formula for a Minkowski observer. We find that there does exist a positive radiated power of quantum nature emitted by the detector, with a hint of certain features of the Unruh effect. We further verify that the total energy of the dressed detector and a part of the radiated energy from the detector is conserved. However, this part of the radiation ceases in steady state. So the hint of the Unruh effect in radiated power is actually not directly from the energy flux that the detector experiences in Unruh effect. Since all the relevant quantum and statistical information about the detector (atom) and the field can be obtained from the results presented here, they are expected to be useful, when appropriately generalized, for addressing issues of quantum information processing in atomic and optical systems, such as quantum decoherence, entanglement and teleportation.

  19. Dynamic Electrothermal Model of a Sputtered Thermopile Thermal Radiation Detector for Earth Radiation Budget Applications

    NASA Technical Reports Server (NTRS)

    Weckmann, Stephanie

    1997-01-01

    The Clouds and the Earth's Radiant Energy System (CERES) is a program sponsored by the National Aeronautics and Space Administration (NASA) aimed at evaluating the global energy balance. Current scanning radiometers used for CERES consist of thin-film thermistor bolometers viewing the Earth through a Cassegrain telescope. The Thermal Radiation Group, a laboratory in the Department of Mechanical Engineering at Virginia Polytechnic Institute and State University, is currently studying a new sensor concept to replace the current bolometer: a thermopile thermal radiation detector. This next-generation detector would consist of a thermal sensor array made of thermocouple junction pairs, or thermopiles. The objective of the current research is to perform a thermal analysis of the thermopile. Numerical thermal models are particularly suited to solve problems for which temperature is the dominant mechanism of the operation of the device (through the thermoelectric effect), as well as for complex geometries composed of numerous different materials. Feasibility and design specifications are studied by developing a dynamic electrothermal model of the thermopile using the finite element method. A commercial finite element-modeling package, ALGOR, is used.

  20. Investigation of voltages and electric fields in silicon radiation detectors using a scanning electron microscope

    NASA Astrophysics Data System (ADS)

    Leinonen, Kari

    2005-12-01

    The paper describes qualitative and quantitative methods to measure voltages and electric fields in a biased silicon p +/n -/n + radiation detector with a scanning electron microscope using voltage-contrast phenomenon. The contrast is converted to voltage mathematically using simple equations. After splitting the detector, voltages and electric fields inside the detector can be imaged and measured. The results are compared with capacitance-voltage measurements and 2D electrical simulations.

  1. Spectroscopic performance and long-term stability of thallium bromide radiation detectors

    Microsoft Academic Search

    Toshiyuki Onodera; Keitato Hitomi; Tadayoshi Shoji

    2006-01-01

    Thallium bromide (TlBr) is a very promising detector material used for X- and gamma-ray spectroscopy due to its high atomic number (Tl: 81 and Br: 35), high density (7.56g\\/cm3) and wide band gap (2.68eV). This paper reports results of research on spectroscopic performance and long-term stability of TlBr radiation detectors. TlBr detectors with simple planar structure have been fabricated from

  2. Study of the charge collection efficiency of CdZnTe radiation detectors

    Microsoft Academic Search

    Y. Nemirovsky; A. Ruzin; G. Asa; J. Gorelik

    1996-01-01

    The charge collection efficiency of CdZnTe radiation detectors with two different configurations: aSchottky diode detector and aresistive detector are compared. The average charge collection efficiencies for three different directions of irradiation (negative electrode,\\u000a positive electrode and perpendicular to the electric field) are calculated. The mobility-lifetime product of the CdZnTe substrates\\u000a is evaluated from the dependence of the measured spectra upon

  3. CdZnTe semiconductor parallel strip Frisch grid radiation detectors

    Microsoft Academic Search

    D. S. McGregor; Z. He; H. A. Seifert; R. A. Rojeski; D. K. Wehe

    1998-01-01

    CdZnTe wide band gap compound semiconducting material offers promise as a room temperature operated gamma ray spectrometer. Position-dependent free charge carrier losses during transport can prevent efficient charge carrier extraction from semiconductor detectors and severely reduce energy resolution. Hole trapping losses in CdZnTe radiation detectors are far worse than electron trapping losses and resolution degradation in CdZnTe detectors results primarily

  4. The design and application of lithium drift silicon diodes as nuclear radiation detectors

    Microsoft Academic Search

    P. E. Gibbons; N. G. Blamires

    1965-01-01

    A range of lithium-drifted silicon radiation detectors is described. Areas up to 8 cm2 and thicknesses up to 0.6 cm have been achieved. At - 20°C, a resolution of 8 kev full width half maximum was obtained on 661 kev beta particles using a 1 cm2 detector 0.1 cm thick. The performance of the detectors is discussed in relation to

  5. Radiation damage in silicon detectors for high-energy physics experiments

    Microsoft Academic Search

    Mara Bruzzi

    2001-01-01

    Radiation effects in silicon detectors are discussed in view of their application in future high-energy physics experiments. An overview is given of the major changes in the operational parameters due to radiation damage and their origin in the radiation-induced microscopic disorder in the silicon bulk. The principal radiation hardening technologies are described that have been adopted by the high-energy physics

  6. Development of bulk GaAs room temperature radiation detectors

    Microsoft Academic Search

    D. S. McGregor; G. F. Knoll; Y. Eisen; R. Brake

    1992-01-01

    Various configurations of Schottky diode detectors were fabricated with bulk crystals of liquid encapsulated Czochralski (LEC) semi-insulating undoped GaAs material. Basic detector construction utilized one Ti\\/Au Schottky contact and one Au\\/Ge\\/Ni alloyed ohmic contact. Pulsed X-ray analysis indicated pulse decay times dependent on bias voltage. Pulse height analysis disclosed nonuniform electric field distributions across the detectors tentatively explained as a

  7. Radiation tolerant design of RLBCS system for RPC detector in LHC experiment

    Microsoft Academic Search

    Wojciech M. Zabolotny; Ignacy M. Kudla; Krzysztof T. Pozniak; Karol Bunkowski; Krzysztof Kierzkowski; Grzegorz Wrochna; Jan Krolikowski

    2005-01-01

    This paper describes the design of the Link Box Control System for the RPC Detector (RLBCS), emphasizing the features needed to assure reliable operation in the irradiated environment of the RPC detector and its neighbourhood. The development process required to balance different factors - radiation hardness, reliability, flexibility, firmware upgrade possibilities, diagnostic features. The final design presented in the paper

  8. Terahertz spectroscopy with a holographic Fourier transform spectrometer plus array detector using coherent synchrotron radiation

    SciTech Connect

    Nikolay I. Agladz, John Klopf, Gwyn Williams, Albert J. Sievers

    2010-06-01

    By use of coherent terahertz synchrotron radiation, we experimentally tested a holographic Fourier transform spectrometer coupled to an array detector to determine its viability as a spectral device. Somewhat surprisingly, the overall performance strongly depends on the absorptivity of the birefringent lithium tantalate pixels in the array detector.

  9. Growth and characterization of CdTe single crystals for radiation detectors

    Microsoft Academic Search

    Minoru Funaki; Tsutomu Ozaki; Kazuyuki Satoh; Ryoichi Ohno

    1999-01-01

    To improve the productivity of CdTe radiation detectors, the crystal growth by traveling heater method (THM) as well as the quality of the fabricated detectors were investigated. In the THM growth, optimization of the solvent volume was found to be essential because it affects the shape of the growth interface. The use of the slightly tilted seed from ?111?B was

  10. Radiation-detector optical-imaging device is of simplified construction

    NASA Technical Reports Server (NTRS)

    1965-01-01

    A simplified radiation detector was designed which employs an activated continuous front surface consisting of either the diffused or barrier type of semiconducting material with a grid structure on the nonactivated side of the detector. Its form may be either a rectangular coordinate or a polar coordinate system.

  11. Evaluating the performance of semiconductor radiation detectors through static charge analysis

    Microsoft Academic Search

    C. L. Lingren; J. F. Butler

    1998-01-01

    This paper presents a new approach to analyzing semiconductor radiation detectors based on considering: (1) static charge when all free charge has been collected and (2) capacitances between electrodes and trapped charge within the crystal. It avoids any direct consideration of free charge motion in the detector. The validity of this “static charge” approach is established by using it to

  12. A simple detector for locating radiography and radiotherapy gamma emitting radiation sources

    Microsoft Academic Search

    P H Burgess

    1983-01-01

    The author provides a simple design of collimated Geiger-Muller tube detector which is simple to construct and would be useful in the recovery of lost gamma radiation sources. The detector is compatible with the majority of ratemeters in present use.

  13. An investigation of the use of semiconductors as detectors of nuclear radiation

    E-print Network

    Ivy, Edward Weber

    1960-01-01

    AN INVESTIGATION OF THE USE OF SEMICONDUCTORS AS DETECTORS OF NUCLEAR RADIATION A Thesis By EDWARD WEBER IVY Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August l960 Major Subject: Electrical Engineering AN INVESTIGATION OF THE USE OF SEMICONDUCTORS AS DETECTORS OF NUCLEAR RADIATION A Thesis By EDWARD WEBER IVY Approved as to style and content by: (Chai man of Co ittee...

  14. Preliminary studies and tests of semiconductors for their use as nuclear radiation detectors

    E-print Network

    Willis, Giles Whitehurst

    1960-01-01

    PRELIMINARY STUDIES AND TESTS OF SEMICONDUCTORS FOR THEIR USE AS NUCLEAR RADIATION DETECTORS A Thesis By Giles Whi tehurst Will is, Jr ~ Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE January 1960 Major Subject: Electrical Engineering PRELIMINARY STUDIES AND TESTS OF SEMI CONDUCTORS FOR THEIR USE AS NUCLEAR RADIATION DETECTORS A Thesis By Giles Whitehurst Willi s& Jr ~ Approved...

  15. Characterizing the radiation response of Cherenkov glass detectors with isotopic sources

    SciTech Connect

    Hayward, J P [University of Tennessee, Knoxville (UTK); Hobbs, C. L. [University of Tennessee, Knoxville (UTK); Bell, Zane W [ORNL; Boatner, Lynn A [ORNL; Johnson, Rose E [ORNL; Ramey, Joanne Oxendine [ORNL; Jellison Jr, Gerald Earle [ORNL; Lillard, Cole R [ORNL; Ramey, Lucas A [ORNL

    2012-01-01

    Abstract Cherenkov detectors are widely used for particle identification and threshold detectors in high-energy physics. Glass Cherenkov detectors that are sensitive to beta emissions originating from neutron activation have been demonstrated recently as a potential replacement for activation foils. In this work, we set the groundwork to evaluate large Cherenkov glass detectors for sensitivity to MeV photons through first understanding the measured response of small Cherenkov glass detectors to isotopic gamma-ray sources. Counting and pulse height measurements are acquired with reflected glass Cherenkov detectors read out with a photomultiplier tube. Simulation was used to inform our understanding of the measured results. This simulation included radioactive source decay, radiation interaction, Cherenkov light generation, optical ray tracing, and photoelectron production. Implications for the use of Cherenkov glass detectors to measure low energy gammaray response are discussed.

  16. Terahertz and Infrared Uncooled Detector Based on a Microcantilever as a Radiation Pressure Sensor

    E-print Network

    Gennady P. Berman; Boris M. Chernobrod; Alan R. Bishop; Vyacheslav N. Gorshkov

    2007-03-05

    We consider a far infrared (terahertz), room-temperature detector based on a microcantilever sensor of the radiation pressure. This system has a significantly higher sensitivity than existing uncooled detectors in the far infrared (terahertz) spectral region. The significant enhancement of sensitivity is due the combination non-absorption detection method and high quality optical microcavity. Our theoretical analysis of the detector sensitivity and numerical simulations demonstrate that the narrowband heterodyne detector with the band width 30 MHz has a minimal measurable intensity by three orders of magnitude less than conventional uncooled detectors. In the case of the broadband detector, the noise equivalent temperature difference (NETD) is 7.6 mK, which is significantly smaller than for conventional uncooled thermal detectors.

  17. Diurnal Variations of Energetic Particle Radiation Dose Measured by the Mars Science Laboratory Radiation Assessment Detector

    NASA Astrophysics Data System (ADS)

    Rafkin, Scot; Zeitlin, Cary; Ehresmann, Bent; Köhler, Jan; Guo, Jingnan; Kahanpää, Henrik; Hassler, Don; -Gomez, Javier E.; Wimmer-Schweingruber, Robert; Brinza, David; Böttcher, Stephan; Böhm, Eckhard; Burmeister, Sonka; Martin, Cesar; Müller-Mellin, Robert; Appel, Jan; Posner, Arik; Reitz, Gunter; Kharytonov, Aliksandr; Cucinotta, Francis

    2013-04-01

    The Radiation Assessment Detector (RAD) on board the Mars Science Laboratory (MSL) rover Curiosity has collected data on the interplanetary radiation environment during cruise from Earth to Mars and at the surface of Mars since its landing in August 2012. RAD's particle detection capabilities are achieved with a solid-state detector (SSD) stack (A, B, C), a CsI(Tl) scintillator (D), and a plastic scintillator (E) for neutron detection. The D and E detectors are surrounded by an anticoincidence shield (F), also made of plastic scintillator. All scintillators are optically coupled to silicon diodes which convert scintillation light to electrons. RAD is capable of measuring both Galactic Cosmic Rays (GCRs) thought to be produced by supernovae outside the heliosphere and Solar Energetic Particles (SEPs). GCRs are relativistic particles (100 MeV/nuc to >10 GeV/nuc) composed of roughly 89% protons, 10% alpha particles (He), and 1% heavier nuclei [1]. Because of their high energies and continuous nature, GCRs are the dominant source of background radiation at the Martian surface, and are responsible for the production of secondary particles (notably neutrons) via complex interactions in the atmosphere and regolith. SEPs are produced by coronal mass ejections. These intermittent storms are most likely to occur near solar maximum and typical fluxes are dominated by protons with energies lower than 100 MeV/nuc. Unlike the GCR flux, the SEP flux can vary by five or more orders of magnitude over timescales of a day. Even under a constant flux of energetic particle radiation at the top of the atmosphere, the radiation dose at the surface should vary as a function of surface elevation [2]. This variation is directly related to the change in the shielding provided by the total atmospheric mass column, which is to a very good approximation directly related to surface pressure. Thus, the flux of primary energetic particles should increase with altitude, all other things being equal. At present, MSL has been at a nearly constant altitude of ~-4.4 km MOLA so that no elevation-induced changes are expected and none have been observed. However, any process that changes the column mass of atmosphere should change the dose at the surface. On Mars there are two major processes that substantially change column atmospheric mass. The first is the seasonal condensation cycle during which ~25% of the dominant atmospheric constituent (CO2) condenses onto the winter pole. This seasonal signal is very strong and has been observed by surface pressure measurements from the Viking Landers up through MSL [3,4]. The second major process is related to the thermal tide. The direct heating of the Martian atmosphere by the Sun produces global scale waves that redistribute mass [5]. The two most dominant tidal modes are the diurnal and semidiurnal tide. Together, the thermal tide can produce a variation of 10-15% over a Martian day (sol). Here, we report on the dose measured by the RAD E detector and the variation of this dose over the diurnal cycle. Further, we show that the variation in the E dose rate is very likely due to the variation of column mass, as measured by the pressure sensor on the Rover Environmental Monitoring Station (REMS), driven by the thermal tide. While changes in dose were expected from changes in altitude or season, the discovery of a diurnal variation was not anticipated, although it should have been reasonably expected in hindsight.

  18. Generic data acquisition system for multi-dimensional radiation detectors

    Microsoft Academic Search

    Adam W. Lynch; Andrew Berry; Goran Panjkovic; Rob Lewis

    2007-01-01

    The instrumentation group at the Monash Centre for Synchrotron Science have developed a low cost generic data acquisition system. This system is to be used in a variety of applications and to assist in the design and testing of emerging detectors. The system utilises a desktop PC which interfaces to a detector via one or more custom 64-bit PCI cards,

  19. Method for mapping charge pulses in semiconductor radiation detectors

    Microsoft Academic Search

    T. H. Prettyman

    1999-01-01

    An efficient method for determining the distribution of charge pulses produced by semiconductor detectors is presented. The method is based on a quasi-steady-state model for semiconductor detector operation. A complete description of the model and the underlying assumptions are given. Mapping of charge pulses is accomplished by solving an adjoint carrier continuity equation. The solution of the adjoint equation yields

  20. Radiation detectors based on microchannel plates for free-electron lasers

    NASA Astrophysics Data System (ADS)

    Syresin, E.; Brovko, O.; Grebentsov, A.; Zamjatin, N.; Shabunov, A.; Yurkov, M.; Gruenert, J.; Freund, W.; Novikov, D.; Basta, R.; Fiala, T.; Hedbavny, P.

    2014-11-01

    Detectors based on microchannel plates are used to detect the radiation of free-electron lasers operating in short-wavelength ranges. We present descriptions of radiation detectors for the FLASH free-electron laser (DESY, Hamburg) that operates in vacuum ultraviolet and soft X-ray wavelength ranges (4-100 nm) and detectors for the European X-ray free electron laser that is being constructed in Hamburg and is designed to operate in the X-ray wavelength range from 0.05 to 4.3 nm.

  1. Nuclear Instruments and Methods in Physics Research A 419 (1998) 556--569 Radiation damage of silicon strip detectors in the NA50 experiment

    E-print Network

    Ramello, Luciano

    to 20 Mrad, with a very non-uniform radiation spatial distribution. Radiation effects in the detectors; Radiation damage 1. Introduction The multiplicity detector in the NA50 experi- ment [1] is one of very few detectors working in a real experiment where silicon detectors are ex- posed to radiation fluences and doses

  2. DEVELOPMENT OF CdZnTe RADIATION DETECTORS

    SciTech Connect

    BOLOTNIKOV, A.; CAMARDA, G.; HOSSAIN, A.; KIM, K.H.; YANG, G.; GUL, R.; CUI, Y.; AND JAMES, R.B.

    2011-10-23

    Cadmium Zinc Telluride (CdZnTe or CZT) is a very attractive material for room-temperature semiconductor detectors because of its wide band-gap and high atomic number. Despite these advantages, CZT still presents some material limitations and poor hole mobility. In the past decade most of the developing CZT detectors focused on designing different electrode configurations, mainly to minimize the deleterious effect due to the poor hole mobility. A few different electrode geometries were designed and fabricated, such as pixelated anodes and Frisch-grid detectors developed at Brookhaven National Lab (BNL). However, crystal defects in CZT materials still limit the yield of detector-grade crystals, and, in general, dominate the detector's performance. In the past few years, our group's research extended to characterizing the CZT materials at the micro-scale, and to correlating crystal defects with the detector's performance. We built a set of unique tools for this purpose, including infrared (IR) transmission microscopy, X-ray micro-scale mapping using synchrotron light source, X-ray transmission- and reflection-topography, current deep level transient spectroscopy (I-DLTS), and photoluminescence measurements. Our most recent work on CZT detectors was directed towards detailing various crystal defects, studying the internal electrical field, and delineating the effects of thermal annealing on improving the material properties. In this paper, we report our most recent results.

  3. Radiation Measurements in Cruise and on Mars by the MSL Radiation Assessment Detector

    NASA Astrophysics Data System (ADS)

    Zeitlin, C. J.; Hassler, D.; Wimmer-Schweingruber, R. F.; Appel, J. K.; Boehm, E.; Boettcher, S.; Brinza, D.; Burmeister, S.; Cucinotta, F.; Ehresmann, B.; Guo, J.; Kohler, J.; Lohf, H.; Martin, C.; Posner, A.; Rafkin, S. C.; Reitz, G.; Team, M.

    2013-12-01

    The Radiation Assessment Detector (RAD) is one of ten science instruments on the Curiosity rover. The RAD team's science objectives include the measurement of radiation dose (a purely physical quantity) and dose equivalent (a derived quantity that can be related to cancer risk) on the surface of Mars. In addition, RAD acquired data for most of the cruise to Mars, from Dec. 2011 through July 2012, providing a measurement of the radiation environment under conditions similar to those expected on a human trip to Mars or other deep space destinations. The dose and dose equivalent measurements made during cruise have been published, but are presented in more detail here. Rates measured in cruise are compared to similar measurements made during Curiosity's first 269 sols on the surface of Mars. In the simplest picture, one expects rates to be a factor of two lower on the surface of a large airless body compared to free space, owing to the two-pi shielding geometry. The situation on Mars is complicated by the non-negligible shielding effects of the atmosphere, particularly in Gale Crater where diurnal variations in atmospheric column depth are significant. The diurnal variations - caused by the well-known thermal tides on Mars - result in reduced shielding of the surface in the afternoon as compared to the night and early morning hours. A major challenge in analyzing the surface data is the treatment of the background radiation dose coming from Curiosity's Radioisotope Thermoelectric Generator (RTG). Prior to launch, RAD acquired data in the full cruise configuration so that this background could be measured with only sea-level cosmic ray muons present - that is, almost all of what was measured was due to the RTG. Those effects could therefore be subtracted from the cruise measurements in a straightforward way. However, the situation on the surface is somewhat different than in cruise, in that the mass that was present above RAD - and caused scattering of particles into the detector - is no longer there. The RTG-induced dose rate in the surface configuration must therefore be less than it was in the cruise configuration, but there is no way to get a direct measurement of the background. Quantifying the change in RTG background is difficult but essential, as the subtraction affects every aspect of the dosimetry. Two approaches have been developed and yield roughly similar results. The differences allow us to estimate the uncertainties arising from the RTG subtraction, and propagate those into the dosimetry results.

  4. Methods for radiation detection and characterization using a multiple detector probe

    DOEpatents

    Akers, Douglas William; Roybal, Lyle Gene

    2014-11-04

    Apparatuses, methods, and systems relating to radiological characterization of environments are disclosed. Multi-detector probes with a plurality of detectors in a common housing may be used to substantially concurrently detect a plurality of different radiation activities and types. Multiple multi-detector probes may be used in a down-hole environment to substantially concurrently detect radioactive activity and contents of a buried waste container. Software may process, analyze, and integrate the data from the different multi-detector probes and the different detector types therein to provide source location and integrated analysis as to the source types and activity in the measured environment. Further, the integrated data may be used to compensate for differential density effects and the effects of radiation shielding materials within the volume being measured.

  5. Radiation hardness trends in new microelectronic technologies for the readout of semiconductor detectors

    NASA Astrophysics Data System (ADS)

    Re, Valerio

    2013-12-01

    The semiconductor detector community is taking advantage of the most recent developments in the field of microelectronics for the design of high performance readout chips. Commercial CMOS foundries are progressing towards an aggressive scaling of the device feature size; 3D integration of two or more CMOS layers might provide an alternative or additional way to increase functional density and improve the performance of the detector system. On the other hand, advanced applications of semiconductor detectors in high energy physics, photon science and space experiments require that sensors and front-end electronics stand high levels of radiation. This paper reviews the main mechanisms that influence the radiation tolerance of nanoscale CMOS devices. This provides the basis for a discussion of the impact of radiation hardness criteria on the design and technology choices for microelectronic chips in new semiconductor detector systems.

  6. Radiation damage study of GaAs detectors irradiated by fast neutrons

    NASA Astrophysics Data System (ADS)

    Linhart, V.; Bém, P.; Götz, M.; Honusek, M.; Mareš, J. J.; Slaví?ek, T.; Sopko, B.; Šime?ková, E.

    2006-07-01

    We investigated the radiation hardness of GaAs pad detectors irradiated by fast neutrons. The main goal was to determine the degradation of the charge collection efficiency (CCE) of the irradiated detectors and to measure the charge transport properties in terms of the ??-product. Several GaAs pad detectors have been irradiated by fast neutrons (2-37 MeV) with varying fluence (10 12-10 15 n/cm 2). Neutrons were produced at a cyclotron by means of the (p,n) reaction on a thick beryllium target. Alpha spectra and I- V curves were obtained before and after irradiation. Basic parameters for description of charge-carrier transport were determined as dependent on radiation damage. The measurements prove a degradation of the CCE and the disappearance of the rectifying junctions of the detectors as result of radiation damage.

  7. The effect of oxygen impurities on radiation hardness of FZ silicon detectors for HEP after neutron, proton and gamma irradiation

    Microsoft Academic Search

    B. Dezillie; Z. Li; V. Eremin; W. Chen; L. J. Zhao

    2000-01-01

    The radiation hardness for fast neutrons, high energy protons and 60Co gamma rays of planar detectors processed from highly oxygenated silicon detectors obtained by using high temperature (1200°C), long time (> 200 hours) oxidation technology, are compared with standard silicon detectors. For fast neutron irradiation it is found that there is no advantage of using highly oxygenated silicon FZ detectors

  8. The effect of oxygen impurities on radiation hardness of FZ silicon detectors for HEP after neutron, proton and gamma irradiation

    Microsoft Academic Search

    B. Dezillie; Z. Li; V. Eremin; W. Chen; L. J. Zhao

    1999-01-01

    Radiation hardness for fast neutrons, high energy protons and 60Co gamma rays of planar detectors processed from highly oxygenated silicon detectors obtained by using the high temperature (1200°C), long time (>200 hours) oxidation technology, are compared with standard silicon detectors. For fast neutron irradiation it is found that there is no advantage of using highly oxygenated silicon FZ detectors as

  9. Developments in gas detectors for synchrotron x-ray radiation

    SciTech Connect

    Fischer, J.; Radeka, V.; Smith, G.C.

    1985-09-01

    New results on the physical limitations to position resolution in gas detectors for x-rays (approx. =3 to 20 keV) due to the range of photoelectrons and Auger electrons are discussed. These results were obtained with a small gap detector in which position readout was accomplished by using a very low noise centroid finding technique. A description is given of position sensitive detectors for medium rates (a few x 10/sup 5/ photons per second), using delay line readout, and for very high rates (approx. =10/sup 8/ photons per second), using fast signal shaping on the output of each anode wire.

  10. Low radioactivity material for use in mounting radiation detectors

    NASA Technical Reports Server (NTRS)

    Fong, Marshall; Metzger, Albert E.; Fox, Richard L.

    1988-01-01

    Two materials, sapphire and synthetic quartz, have been found for use in Ge detector mounting assemblies. These materials combine desirable mechanical, thermal, and electrical properties with the radioactive cleanliness required to detect minimal amounts of K, Th, and U.

  11. Calibration of VUV spectrometer-detector system using synchrotron radiation

    Microsoft Academic Search

    Armon McPherson; Ned Rouze; W. B. Westerveld; John S. Risley

    1986-01-01

    A new technique and apparatus have been developed for the measurement of absolute electron impact photoemission cross sections in the 30--150-nm wavelength range. Synchrotron light is used as the primary intensity standard for the calibration of the detection efficiency of a vacuum ultraviolet (VUV) spectrometer-detector system. A multiadjustable manipulator was used to position precisely a Seya-Namioka-type spectrometer-detector system with respect

  12. Operation and radiation resistance of a FOXFET biasing structure for silicon strip detectors

    SciTech Connect

    Laakso, M. [Fermi National Accelerator Lab., Batavia, IL (United States)]|[Helsinki Univ. (Finland). Dept. of High Energy Physics; Singh, P.; Engels, E. Jr.; Shepard, P. [Pittsburgh Univ., PA (United States). Dept. of Physics and Astronomy

    1992-02-01

    AC-coupled strip detectors biased with a FOXFET transistor structure have been studied. Measurement results for the basic operational characteristics of the FOXFET are presented together with a brief description of the physics underlying its operation. Radiation effects were studied using photons from a {sup 137}Cs source. Changes in the FOXFET characteristics as a function of radiation dose up to 1 MRad are reported. Results about the effect of radiation on the noise from a FOXFET biased detector are described. 13 refs.

  13. Simulation of ion beam induced current in radiation detectors and microelectronic devices.

    SciTech Connect

    Vizkelethy, Gyorgy

    2009-10-01

    Ionizing radiation is known to cause Single Event Effects (SEE) in a variety of electronic devices. The mechanism that leads to these SEEs is current induced by the radiation in these devices. While this phenomenon is detrimental in ICs, this is the basic mechanism behind the operation of semiconductor radiation detectors. To be able to predict SEEs in ICs and detector responses we need to be able to simulate the radiation induced current as the function of time. There are analytical models, which work for very simple detector configurations, but fail for anything more complex. On the other end, TCAD programs can simulate this process in microelectronic devices, but these TCAD codes costs hundreds of thousands of dollars and they require huge computing resources. In addition, in certain cases they fail to predict the correct behavior. A simulation model based on the Gunn theorem was developed and used with the COMSOL Multiphysics framework.

  14. A program in detector development for the US synchrotron radiation community

    SciTech Connect

    Thompson, A.; Mills, D.; Naday, S.; Gruner, S.; Siddons, P.; Arthur, J.; Wehlitz, R.; Padmore, H.

    2001-07-14

    There is a clear gulf between the capabilities of modern synchrotrons to deliver high photon fluxes, and the capabilities of detectors to measure the resulting photon, electron or ion signals. While a huge investment has been made in storage ring technology, there has not to date been a commensurate investment in detector systems. With appropriate detector technology, gains in data rates could be 3 to 4 orders of magnitude in some cases. The US community working in detector technology is under-funded and fragmented and works without the long term funding commitment required for development of the most advanced detector systems. It is becoming apparent that the US is falling behind its international competitors in provision of state-of-the-art detector technology for cutting edge synchrotron radiation based experiments.

  15. Over-response of synthetic microDiamond detectors in small radiation fields.

    PubMed

    Ralston, Anna; Tyler, Madelaine; Liu, Paul; McKenzie, David; Suchowerska, Natalka

    2014-10-01

    The recently commercialized PTW microDiamond detector (T60019) has been designed for use in small radiation fields. Here we report on the measurement of relative output ratios for small fields using five microDiamond detectors. All of the microDiamond detectors over-responded in fields smaller than 20?mm, by up to 9.3% for a 4?mm field. The over-response was independent of accelerator type and choice of collimation. The over-response was slightly larger than that observed in silicon diodes. Since all five microDiamond detectors showed the same over-response the corrections presented here should be transferable to other examples of the microDiamond detector, provided that the detector meets the manufacturing specifications and the beam characteristics are comparable. PMID:25211368

  16. Coupled Deterministic/Monte Carlo Simulation of Radiation Transport and Detector Response

    SciTech Connect

    Gesh, Christopher J.; Meriwether, George H.; Pagh, Richard T.; Smith, Leon E.

    2005-09-01

    The analysis of radiation sensor systems used to detect and identify nuclear and radiological weapons materials requires detailed radiation transport calculations. Two basic steps are required to solve radiation detection scenario analysis (RDSA) problems. First, the radiation field produced by the source must be calculated. Second, the response that the radiation field produces in a detector must be determined. RDSA problems are characterized by complex geometries, the presence of shielding materials, and large amounts of scattering (or absorption/re-emission). In this paper, we will discuss the use of the Attila code [2] for RDSA.

  17. Electromagnetic and nuclear radiation detector using micromechanical sensors

    DOEpatents

    Thundat, Thomas G. (Knoxville, TN); Warmack, Robert J. (Knoxville, TN); Wachter, Eric A. (Oak Ridge, TN)

    2000-01-01

    Electromagnetic and nuclear radiation is detected by micromechanical sensors that can be coated with various interactive materials. As the micromechanical sensors absorb radiation, the sensors bend and/or undergo a shift in resonance characteristics. The bending and resonance changes are detected with high sensitivity by any of several detection methods including optical, capacitive, and piezoresistive methods. Wide bands of the electromagnetic spectrum can be imaged with picoJoule sensitivity, and specific absorptive coatings can be used for selective sensitivity in specific wavelength bands. Microcantilevers coated with optical cross-linking polymers are useful as integrating optical radiation dosimeters. Nuclear radiation dosimetry is possible by fabricating cantilevers from materials that are sensitive to various nuclear particles or radiation. Upon exposure to radiation, the cantilever bends due to stress and its resonance frequency shifts due to changes in elastic properties, based on cantilever shape and properties of the coating.

  18. Radiation Hard AlGaN Detectors and Imager

    SciTech Connect

    None

    2012-05-01

    Radiation hardness of AlGaN photodiodes was tested using a 65 MeV proton beam with a total proton fluence of 3x10{sup 12} protons/cm{sup 2}. AlGaN Deep UV Photodiode have extremely high radiation hardness. These new devices have mission critical applications in high energy density physics (HEDP) and space explorations. These new devices satisfy radiation hardness requirements by NIF. NSTec is developing next generation AlGaN optoelectronics and imagers.

  19. A hollow sphere as a detector of gravitational radiation

    E-print Network

    E. Coccia; V. Fafone; G. Frossati; J. A. Lobo; J. A. Ortega

    1997-07-30

    The most important features of the proposed spherical gravitational wave detectors are closely linked with their symmetry. Hollow spheres share this property with solid ones, considered in the literature so far, and constitute an interesting alternative for the realization of an omnidirectional gravitational wave detector. In this paper we address the problem of how a hollow elastic sphere interacts with an incoming gravitational wave and find an analytical solution for its normal mode spectrum and response, as well as for its energy absorption cross sections. It appears that this shape can be designed having relatively low resonance frequencies (about 200 Hz) yet keeping a large cross section, so its frequency range overlaps with the projected large interferometers. We also apply the obtained results to discuss the performance of a hollow sphere as a detector for a variety of gravitational wave signals.

  20. Time dependence of the behaviour of silicon detectors in intense radiation fields and the role of primary point defects

    E-print Network

    Sorina Lazanu; Ionel Lazanu

    2006-11-08

    The bulk displacement damage in the detector, produces effects at the device level that limits the long time utilisation of detectors as position sensitive devices and thus the lifetime of detector systems. So, the prediction of time behaviour of detectors in hostile radiation environments represents a very useful tool. In this contribution we predict the time degradation of silicon detectors in the radiation environments expected in the LHC machine upgrade in luminosity and energy as SLHC, for detectors fabricated from silicon crystals obtained by different growth technologies, in the frame of the model developed by the authors, and which takes into account the contribution of primary defects.

  1. Electromagnetic and nuclear radiation detector using micromechanical sensors

    Microsoft Academic Search

    Thomas G. Thundat; Robert J. Warmack; Eric A. Wachter

    2000-01-01

    Electromagnetic and nuclear radiation is detected by micromechanical sensors that can be coated with various interactive materials. As the micromechanical sensors absorb radiation, the sensors bend and\\/or undergo a shift in resonance characteristics. The bending and resonance changes are detected with high sensitivity by any of several detection methods including optical, capacitive, and piezoresistive methods. Wide bands of the electromagnetic

  2. Preparation and Characteristics of Natural Diamond Nuclear Radiation Detectors

    Microsoft Academic Search

    S. F. Kozlov; R. Stuck; M. Hage-Ali; P. Siffert

    1975-01-01

    It is shown that natural diamond can be used as a homogeneous conduction counter with near complete charge collection, even over a long period of time. Indeed, polarization effects have been suppressed by making the back contact of the detector injecting under the influence of the applied field in order to compensate for trapped charge carriers. The electric and detection

  3. Radiation-hard semiconductor detectors for SuperLHC

    Microsoft Academic Search

    M. Bruzzi; J. Adey; A. Al-Ajili; P. Alexandrov; G. Alfieri; P. P. Allport; A. Andreazza; M. Artuso; S. Assouak; B. S. Avset; L. Barabash; E. Baranova; A. Barcz; A. Basile; R. Bates; N. Belova; S. F. Biagi; G. M. Bilei; D. Bisello; A. Blue; A. Blumenau; V. Boisvert; G. Bolla; G. Bondarenko; E. Borchi; L. Borrello; D. Bortoletto; M. Boscardin; L. Bosisio; T. J. V. Bowcock; T. J. Brodbeck; J. Broz; A. Brukhanov; A. Brzozowski; M. Buda; P. Buhmann; C. Buttar; F. Campabadal; D. Campbell; A. Candelori; G. Casse; A. Cavallini; A. Chilingarov; D. Chren; V. Cindro; M. Citterio; P. Collins; R. Coluccia; D. Contarato; J. Coutinho; D. Creanza; W. Cunningham; V. Cvetkov; G.-F. Dalla Betta; G. Davies; I. Dawson; W. de Boer; M. De Palma; R. Demina; P. Dervan; A. Dierlamm; S. Dittongo; L. Dobrzanski; Z. Dolezal; A. Dolgolenko; T. Eberlein; V. Eremin; C. Fall; F. Fasolo; T. Ferbel; F. Fizzotti; C. Fleta; E. Focardi; E. Forton; S. Franchenko; E. Fretwurst; F. Gamaz; C. Garcia; J. E. Garcia-Navarro; E. Gaubas; M.-H. Genest; K. A. Gill; K. Giolo; M. Glaser; C. Goessling; V. Golovine; S. González Sevilla; I. Gorelov; J. Goss; A. Gouldwell; G. Grégoire; P. Gregori; E. Grigoriev; C. Grigson; A. Grillo; A. Groza; J. Guskov; L. Haddad; J. Härkönen; R. Harding; F. Hauler; S. Hayama; M. Hoeferkamp; F. Hönniger; T. Horazdovsky; R. Horisberger; M. Horn; A. Houdayer; B. Hourahine; A. Hruban; G. Hughes; I. Ilyashenko; K. Irmscher; A. Ivanov; K. Jarasiunas; T. Jin; B. K. Jones; R. Jones; C. Joram; L. Jungermann; E. Kalinina; P. Kaminski; A. Karpenko; A. Karpov; V. Kazlauskiene; V. Kazukauskas; V. Khivrich; V. Khomenkov; J. Kierstead; J. Klaiber-Lodewigs; M. Kleverman; R. Klingenberg; P. Kodys; Z. Kohout; S. Korjenevski; A. Kowalik; R. Kozlowski; M. Kozodaev; G. Kramberger; O. Krasel; A. Kuznetsov; S. Kwan; S. Lagomarsino; T. Lari; K. Lassila-Perini; V. Lastovetsky; G. Latino; S. Latushkin; S. Lazanu; I. Lazanu; C. Lebel; K. Leinonen; C. Leroy; Z. Li; G. Lindström; L. Lindstrom; V. Linhart; A. Litovchenko; P. Litovchenko; V. Litvinov; A. Lo Giudice; M. Lozano; Z. Luczynski; P. Luukka; A. Macchiolo; A. Mainwood; L. F. Makarenko; I. Mandi?; C. Manfredotti; S. Marti i Garcia; S. Marunko; K. Mathieson; A. Mozzanti; J. Melone; D. Menichelli; C. Meroni; A. Messineo; S. Miglio; M. Mikuz; J. Miyamoto; M. Moll; E. Monakhov; F. Moscatelli; L. Murin; F. Nava; D. Naoumov; E. Nossarzewska-Orlowska; S. Nummela; J. Nysten; P. Olivero; V. Oshea; T. Palviainen; C. Paolini; C. Parkes; D. Passeri; U. Pein; G. Pellegrini; L. Perera; M. Petasecca; B. Piatkowski; C. Piemonte; G. U. Pignatel; N. Pinho; I. Pintilie; L. Pintilie; L. Polivtsev; P. Polozov; A. I. Popa; J. Popule; S. Pospisil; G. Pucker; V. Radicci; J. M. Rafí; F. Ragusa; M. Rahman; R. Rando; R. Roeder; T. Rohe; S. Ronchin; C. Rott; P. Roy; A. Roy; A. Ruzin; A. Ryazanov; H. F. W. Sadrozinski; S. Sakalauskas; M. Scaringella; L. Schiavulli; S. Schnetzer; B. Schumm; S. Sciortino; A. Scorzoni; G. Segneri; S. Seidel; A. Seiden; G. Sellberg; P. Sellin; D. Sentenac; I. Shipsey; P. Sicho; T. Sloan; M. Solar; S. Son; B. Sopko; N. Spencer; J. Stahl; I. Stavitski; D. Stolze; R. Stone; J. Storasta; N. Strokan; W. Strupinski; M. Sudzius; B. Surma; J. Suuronen; A. Suvorov; B. G. Svensson; P. Tipton; M. Tomasek; C. Troncon; A. Tsvetkov; E. Tuominen; E. Tuovinen; T. Tuuva; M. Tylchin; H. Uebersee; J. Uher; M. Ullán; J. V. Vaitkus; P. Vanni; J. Velthuis; G. Verzellesi; E. Verbitskaya; V. Vrba; G. Wagner; I. Wilhelm; S. Worm; V. Wright; R. Wunstorf; P. Zabierowski; A. Zaluzhny; M. Zavrtanik; M. Zen; V. Zhukov; N. Zorzi

    2005-01-01

    An option of increasing the luminosity of the Large Hadron Collider (LHC) at CERN to 1035cm?2s?1 has been envisaged to extend the physics reach of the machine. An efficient tracking down to a few centimetres from the interaction point will be required to exploit the physics potential of the upgraded LHC. As a consequence, the semiconductor detectors close to the

  4. Active noise canceling system for mechanically cooled germanium radiation detectors

    DOEpatents

    Nelson, Karl Einar; Burks, Morgan T

    2014-04-22

    A microphonics noise cancellation system and method for improving the energy resolution for mechanically cooled high-purity Germanium (HPGe) detector systems. A classical adaptive noise canceling digital processing system using an adaptive predictor is used in an MCA to attenuate the microphonics noise source making the system more deployable.

  5. Radiation pressure induced instabilities in laser interferometric detectors of gravitational waves

    Microsoft Academic Search

    A. Pai; S. V. Dhurandhar; P. Hello; J.-Y. Vinet

    2000-01-01

    The large scale interferometric gravitational wave detectors consist of Fabry-Perot cavities operating at very high powers\\u000a ranging from tens of kW to MW for next generations. The high powers may result in several nonlinear effects which would affect\\u000a the performance of the detector. In this paper, we investigate the effects of radiation pressure, which tend to displace the\\u000a mirrors from

  6. Purification and preparation of TlBr crystals for room temperature radiation detector applications

    Microsoft Academic Search

    Icimone B. Oliveira; Fábio E. Costa; José F. D. Chubaci; Margarida M. Hamada

    2004-01-01

    Thallium bromide (TlBr) is a semiconductor compound with a high atomic number and a wide bandgap, being a very promising material to be used as room temperature radiation detectors. In this work, commercial TlBr powder was used for growing crystals for detector applications. To reduce impurities, this material was purified by the zone refining technique. Trace impurities at ppb\\/ppm level

  7. Cumulative effects of Te precipitates in CdZnTe radiation detectors

    Microsoft Academic Search

    A. E. Bolotnikov; G. S. Camarda; G. A. Carini; Y. Cui; L. Li; R. B. James

    2007-01-01

    High-quality radiation detector-grade CdZnTe material is free from large-scale defects, such as grain boundaries, twins, and large Te or Cd inclusions (>50?m), although it usually contains high concentrations of uniformly distributed Te inclusions and precipitates, typically of ?20-?m-diameter size or smaller. We address the effects of the small-size Te precipitates on charge collection in CZT detectors, the significance of which

  8. Radiation hard silicon detectors—developments by the RD48 (ROSE) collaboration

    Microsoft Academic Search

    G. Lindström; M. Ahmed; S. Albergo; P. Allport; D. Anderson; L. Andricek; M. M. Angarano; V. Augelli; N. Bacchetta; P. Bartalini; R. Bates; U. Biggeri; G. M. Bilei; D. Bisello; D. Boemi; E. Borchi; T. Botila; T. J. Brodbeck; M. Bruzzi; T. Budzynski; P. Burger; F. Campabadal; G. Casse; E. Catacchini; A. Chilingarov; P. Ciampolini; V. Cindro; M. J. Costa; D. Creanza; P. Clauws; C Da Via; G. Davies; W De Boer; R Dell’Orso; M De Palma; B. Dezillie; V. Eremin; O. Evrard; G. Fallica; G. Fanourakis; H. Feick; E. Fretwurst; L. Fonseca; J. Fuster; K. Gabathuler; M. Glaser; P. Grabiec; E. Grigoriev; G. Hall; M. Hanlon; F. Hauler; S. Heising; A. Holmes-Siedle; R. Horisberger; G. Hughes; M. Huhtinen; I. Ilyashenko; A. Ivanov; B. K Jones; L. Jungermann; A. Kaminsky; Z. Kohout; G. Kramberger; M. Kuhnke; S. Kwan; F. Lemeilleur; C. Leroy; M. Letheren; Z. Li; T. Ligonzo; V. Linhart; P. Litovchenko; D. Loukas; M. Lozano; Z. Luczynski; G. Lutz; B. MacEvoy; S. Manolopoulos; A. Markou; C. Martinez; A. Messineo; M. Mikuz; M. Moll; E. Nossarzewska; G. Ottaviani; V. Oshea; G. Parrini; D. Passeri; D. Petre; A. Pickford; I. Pintilie; L. Pintilie; S. Pospisil; R. Potenza; C. Raine; J. M Rafi; P. N Ratoff; R. H Richter; P. Riedler; S. Roe; P. Roy; A. Ruzin; A. I. Ryazanov; A. Santocchia; L. Schiavulli; P. Sicho; I. Siotis; T. Sloan; W. Slysz; K. Smith; M. Solanky; B. Sopko; K. Stolze; B Sundby Avset; B. Svensson; C. Tivarus; G. Tonelli; A. Tricomi; S. Tzamarias; G. Valvo; A. Vasilescu; A. Vayaki; E. Verbitskaya; P. Verdini; V. Vrba; S. Watts; E. R Weber; M. Wegrzecki; I. Wegrzecka; P. Weilhammer; R. Wheadon; C. Wilburn; I. Wilhelm; R. Wunstorf; J. Wüstenfeld; J. Wyss; K. Zankel; P. Zabierowski; D Žontar

    2001-01-01

    The RD48 (ROSE) collaboration has succeeded to develop radiation hard silicon detectors, capable to withstand the harsh hadron fluences in the tracking areas of LHC experiments. In order to reach this objective, a defect engineering technique was employed resulting in the development of Oxygen enriched FZ silicon (DOFZ), ensuring the necessary O-enrichment of about 2×1017 O\\/cm3 in the normal detector

  9. Novel p-JFET embedded in silicon radiation detectors that avoids preamplifier feedback resistor

    Microsoft Academic Search

    M. Sampietro; L. Fasoli; P. Rehak; L. Struder

    1995-01-01

    The paper describes the design and the performance of an original p-channel JFET embedded in the collecting anode of a silicon radiation detector. The choice of a p-channel transistor, whose gate-to-channel junction is forward biased by the leakage current from the detector, avoids the preamplifier feedback resistor and performs a continuous dc reset of the collected charge. The reported design,

  10. Coaxial nuclear radiation detector with deep junction and radial field gradient

    Microsoft Academic Search

    Hall

    1979-01-01

    Germanium radiation detectors are manufactured by diffusion lithium into high purity p-type germanium. The diffusion is most readily accomplished from a lithium-lead-bismuth alloy at approximately 430° and is monitored by a quartz half cell containing a standard composition of this alloy. Detectors having n-type cores may be constructed by converting high purity p-type germanium to n-type by a lithium diffusion

  11. X-ray diffuse scattering for evaluation of wide bandgap semiconductor nuclear radiation detectors

    Microsoft Academic Search

    M. S Goorsky; H. Yoon; M. Schieber; R. B James; D. S McGregor; M. Natarajan

    1996-01-01

    The crystalline perfection of solid state radiation detectors was examined using triple axis x-ray diffraction. Triple axis techniques provide a means to analyze the origin of diffraction peak broadening: the effects of strain (due to deviations in alloy composition or stoichiometry) and lattice tilts (mosaic structure) can be separated. Cd1 ? xZnxTe (x ? 0.1), HgI2, and GaAs detector materials

  12. Structural properties of cadmium zinc telluride and their effects on nuclear radiation detector performance

    Microsoft Academic Search

    Hojun Yoon

    1998-01-01

    Structural properties of cadmium zinc telluride, Cdsb{1-x}Znsb{x}Te, used as room temperature nuclear radiation detectors are characterized in relation to various detector properties. Alloy (zinc) composition variation is determined by triple axis diffraction lattice parameter measurements and its effects on the material resistivity are examined. Structural defects including cracks, grain\\/twin boundaries, mosaic structure, small angle tilt boundaries, and dislocations are characterized

  13. Picosecond YBa2Cu3O(7-delta) detector for far-infrared radiation

    Microsoft Academic Search

    R. S. Nebosis; R. Steinke; P. T. Lang; W. Schatz; M. A. Heusinger; K. F. Renk; G. N. Gol'Tsman; B. S. Karasik; A. D. Semenov; E. M. Gershenzon

    1992-01-01

    We report on a picosecond YBa2Cu3O(7-delta) detector for far-infrared radiation. The detector, consisting of a current carrying structure cooled to liquid-nitrogen temperature, was studied by use of ultrashort laser pulses from an optically pumped far-infrared laser in the frequency range from 25 to 215\\/cm. We found that the sensitivity (1 mV\\/W) was almost constant in this frequency range. We estimated

  14. Characterization of Semi-Insulating 4H Silicon Carbide for Radiation Detectors

    Microsoft Academic Search

    Krishna C. Mandal; Ramesh M. Krishna; Peter G. Muzykov; Sandip Das; Tangali S. Sudarshan

    2011-01-01

    Radiation detectors have been fabricated on 8 mm 8 mm substrates, m in thickness, diced from a (0001) 4H-SiC semi-insulating (SI) wafer ( Ohm-cm). The crystals used for detector fabrication have been character- ized by x-ray diffraction (XRD), electron beam induced current (EBIC), chemical etching, cross-polarized imaging, and Raman spectroscopy. Current-voltage (I-V) characteristics showed very low leakage current ( pA

  15. A transition radiation detector for RHIC featuring accurate tracking and dE/dx particle identification

    SciTech Connect

    O`Brien, E.; Lissauer, D.; McCorkle, S.; Polychronakos, V.; Takai, H. [Brookhaven National Lab., Upton, NY (United States); Chi, C.Y.; Nagamiya, S.; Sippach, W.; Toy, M.; Wang, D.; Wang, Y.F.; Wiggins, C.; Willis, W. [Columbia Univ., New York, NY (United States); Cherniatin, V.; Dolgoshein, B. [Moscow Institute of Physics and Engineering, (Russian Federation); Bennett, M.; Chikanian, A.; Kumar, S.; Mitchell, J.T.; Pope, K. [Yale Univ., New Haven, CT (United States)

    1991-12-31

    We describe the results of a test ran involving a Transition Radiation Detector that can both distinguish electrons from pions which momenta greater titan 0.7 GeV/c and simultaneously track particles passing through the detector. The particle identification is accomplished through a combination of the detection of Transition Radiation from the electron and the differences in electron and pion energy loss (dE/dx) in the detector. The dE/dx particle separation is most, efficient below 2 GeV/c while particle ID utilizing Transition Radiation effective above 1.5 GeV/c. Combined, the electron-pion separation is-better than 5 {times} 10{sup 2}. The single-wire, track-position resolution for the TRD is {approximately}230 {mu}m.

  16. Review on the characteristics of radiation detectors for dosimetry and imaging

    NASA Astrophysics Data System (ADS)

    Seco, Joao; Clasie, Ben; Partridge, Mike

    2014-10-01

    The enormous advances in the understanding of human anatomy, physiology and pathology in recent decades have led to ever-improving methods of disease prevention, diagnosis and treatment. Many of these achievements have been enabled, at least in part, by advances in ionizing radiation detectors. Radiology has been transformed by the implementation of multi-slice CT and digital x-ray imaging systems, with silver halide films now largely obsolete for many applications. Nuclear medicine has benefited from more sensitive, faster and higher-resolution detectors delivering ever-higher SPECT and PET image quality. PET/MR systems have been enabled by the development of gamma ray detectors that can operate in high magnetic fields. These huge advances in imaging have enabled equally impressive steps forward in radiotherapy delivery accuracy, with 4DCT, PET and MRI routinely used in treatment planning and online image guidance provided by cone-beam CT. The challenge of ensuring safe, accurate and precise delivery of highly complex radiation fields has also both driven and benefited from advances in radiation detectors. Detector systems have been developed for the measurement of electron, intensity-modulated and modulated arc x-ray, proton and ion beams, and around brachytherapy sources based on a very wide range of technologies. The types of measurement performed are equally wide, encompassing commissioning and quality assurance, reference dosimetry, in vivo dosimetry and personal and environmental monitoring. In this article, we briefly introduce the general physical characteristics and properties that are commonly used to describe the behaviour and performance of both discrete and imaging detectors. The physical principles of operation of calorimeters; ionization and charge detectors; semiconductor, luminescent, scintillating and chemical detectors; and radiochromic and radiographic films are then reviewed and their principle applications discussed. Finally, a general discussion of the application of detectors for x-ray nuclear medicine and ion beam imaging and dosimetry is presented.

  17. Review on the characteristics of radiation detectors for dosimetry and imaging.

    PubMed

    Seco, Joao; Clasie, Ben; Partridge, Mike

    2014-10-21

    The enormous advances in the understanding of human anatomy, physiology and pathology in recent decades have led to ever-improving methods of disease prevention, diagnosis and treatment. Many of these achievements have been enabled, at least in part, by advances in ionizing radiation detectors. Radiology has been transformed by the implementation of multi-slice CT and digital x-ray imaging systems, with silver halide films now largely obsolete for many applications. Nuclear medicine has benefited from more sensitive, faster and higher-resolution detectors delivering ever-higher SPECT and PET image quality. PET/MR systems have been enabled by the development of gamma ray detectors that can operate in high magnetic fields. These huge advances in imaging have enabled equally impressive steps forward in radiotherapy delivery accuracy, with 4DCT, PET and MRI routinely used in treatment planning and online image guidance provided by cone-beam CT. The challenge of ensuring safe, accurate and precise delivery of highly complex radiation fields has also both driven and benefited from advances in radiation detectors. Detector systems have been developed for the measurement of electron, intensity-modulated and modulated arc x-ray, proton and ion beams, and around brachytherapy sources based on a very wide range of technologies. The types of measurement performed are equally wide, encompassing commissioning and quality assurance, reference dosimetry, in vivo dosimetry and personal and environmental monitoring. In this article, we briefly introduce the general physical characteristics and properties that are commonly used to describe the behaviour and performance of both discrete and imaging detectors. The physical principles of operation of calorimeters; ionization and charge detectors; semiconductor, luminescent, scintillating and chemical detectors; and radiochromic and radiographic films are then reviewed and their principle applications discussed. Finally, a general discussion of the application of detectors for x-ray nuclear medicine and ion beam imaging and dosimetry is presented. PMID:25229250

  18. Fabrication process development for high-purity germanium radiation detectors with amorphous semiconductor contacts

    NASA Astrophysics Data System (ADS)

    Looker, Quinn

    High-purity germanium (HPGe) radiation detectors are well established as a valuable tool in nuclear science, astrophysics, and nuclear security applications. HPGe detectors excel in gamma-ray spectroscopy, offering excellent energy resolution with large detector sizes for high radiation detection efficiency. Although a robust fabrication process has been developed, improvement is needed, especially in developing electrical contact and surface passivation technology for position-sensitive detectors. A systematic study is needed to understand how the detector fabrication process impacts detector performance and reliability. In order to provide position sensitivity, the electrical contacts are segmented to form multiple electrodes. This segmentation creates new challenges in the fabrication process and warrants consideration of additional detector effects related to the segmentation. A key area of development is the creation of the electrical contacts in a way that enables reliable operation, provides low electronic noise, and allows fine segmentation of electrodes, giving position sensitivity for radiation interactions in the detector. Amorphous semiconductor contacts have great potential to facilitate new HPGe detector designs by providing a thin, high-resistivity surface coating that is the basis for electrical contacts that block both electrons and holes and can easily be finely segmented. Additionally, amorphous semiconductor coatings form a suitable passivation layer to protect the HPGe crystal surface from contamination. This versatility allows a simple fabrication process for fully passivated, finely segmented detectors. However, the fabrication process for detectors with amorphous semiconductors is not as highly developed as for conventional technologies. The amorphous semiconductor layer properties can vary widely based on how they are created and these can translate into varying performance of HPGe detectors with these contacts. Some key challenges include minimizing charge injection leakage current, increasing the long-term stability of the contacts, and achieving good charge collection properties in segmented detectors. A systematic study of contact characteristics is presented where amorphous germanium (a-Ge) and amorphous silicon (a-Si) contacts are sputtered with varying sputter gas hydrogen content, sputter gas pressure, and amorphous film thickness. A set of about 45 detectors fabricated from 11 different crystal samples were analyzed for electron barrier height and effective Richardson constant. Most of these detectors were subjected to as many as 10 temperature cycles over a period of up to several months in order to assess their long-term stability. Additionally, 6 double-sided strip detectors were fabricated with a-Ge and a-Si contacts in order to study their inter-electrode charge collection properties. An attempt is made to relate fabrication process parameters such as hydrogen content, sputter pressure, and film thickness to changes observed in detector performance and assess the level of reproducibility using the current methods. Several important results and conclusions were found that enable more reliable and highly performing detectors with amorphous semiconductor contacts. Utilizing the new information should enable consistent production of finely segmented detectors with excellent energy resolution that can be operated reliably for a long period of time. The passivation process could impact planar detectors as well as other designs, such as the p-type point contact detector. It is demonstrated that the long-term stability of amorphous semiconductor contacts is primarily dependent on the time the detector is at room temperature rather than the number of temperature cycles. For a-Ge contacts, higher sputter pressure yields a more stable process that changes little with time, giving a reliable hole-blocking contact. The a-Si contacts form a good electron-blocking contact with decreasing leakage current over time. Both materials, when 7% hydrogen is included in the argon sputter gas, show acceptab

  19. Internal Electric Field Behavior of Cadmium Zinc Telluride Radiation Detectors Under High Carrier Injection

    SciTech Connect

    Yang, G.; Bolotnikov, A.E.; Camarda, G.S.; Cui, Y.; Hossain, A.; Kim, K.H.; Gul, R.; and James, R.B.

    2010-10-26

    The behavior of the internal electric-field of nuclear-radiation detectors substantially affects the detector's performance. We investigated the distribution of the internal field in cadmium zinc telluride (CZT) detectors under high carrier injection. We noted the build-up of a space charge region near the cathode that produces a built-in field opposing the applied field. Its presence entails the collapse of the electric field in the rest of detector, other than the portion near the cathode. Such a space-charge region originates from serious hole-trapping in CZT. The device's operating temperature greatly affects the width of the space-charge region. With increasing temperature from 5 C to 35 C, its width expanded from about 1/6 to 1/2 of the total depth of the detector.

  20. High-resolution detectors for medical applications and synchrotron radiation research

    NASA Astrophysics Data System (ADS)

    Babichev, E. A.; Baru, S. E.; Grigoriev, D. N.; Groshev, V. R.; Leonov, V. V.; Papushev, P. A.; Porosev, V. V.; Savinov, G. A.; Shayakhmetov, V. R.; Shekhtman, L. I.; Tikhonov, Yu. A.; Ukraintsev, Yu. G.; Yurchenko, Yu. B.

    2011-02-01

    In the present report, we summarize our experience in the development of high-resolution position sensitive gas detectors for medicine and synchrotron radiation experiments at Budker Institute of Nuclear Physics for the last years. We have designed several versions of Multistrip Ionisation Chambers with a channel pitch varying from 0.4 down to 0.1 mm. The high quantum efficiency (>65%) of these detectors allow its application in high quality diagnostic imaging. The detector with 0.1 mm strip pitch and 20 atm pressure of Xe demonstrates the best possible DQE and spatial resolution for gaseous detectors in a wide range of X-ray energies. Additionally, the initial results of feasibility study of the detector for beam position monitoring for Heavy Ion Therapy System are presented too.

  1. High-energy cosmic-ray electrons - A new measurement using transition-radiation detectors

    NASA Technical Reports Server (NTRS)

    Hartmann, G.; Mueller, D.; Prince, T.

    1977-01-01

    A new detector for cosmic-ray electrons, consisting of a combination of a transition-radiation detector and a shower detector, has been constructed, calibrated at accelerator beams, and exposed in a balloon flight under 5 g/sq cm of atmosphere. The design of this instrument and the methods of data analysis are described. Preliminary results in the energy range 9-300 GeV are presented. The energy spectrum of electrons is found to be significantly steeper than that of protons, consistent with a long escape lifetime of cosmic rays in the galaxy.

  2. Radiation damage due to NIEL in GaAs particle detectors

    NASA Astrophysics Data System (ADS)

    Chilingarov, A.; Meyer, J. S.; Sloan, T.

    1997-08-01

    The Non-Ionizing Energy Loss (NIEL) for fast neutrons, protons and pions in GaAs has been estimated from published calculations. The values are then used to search for a correlation between the observed reduction of charge collection efficiency (CCE) in GaAs particle detectors with the radiation dose from NIEL. A correlation is demonstrated to be present for detectors made from a wide range of material. The implications for the performance of GaAs detectors at the Large Hadron Collider (LHC) are discussed.

  3. Development of passive radiation detectors of improved sensitivity

    NASA Technical Reports Server (NTRS)

    Chakrabarty, M. R.

    1986-01-01

    The future development of a solid track high energy particle detector is discussed. The goal is to improve the sensitivity and lower the threshold of the detector. One most widely used material for such purpose is a plastic commercially known as CR-39. A scheme is presented which involves changing the formula of the monomer, diethylene glycol-bis-allyl carbonate. This is to be accomplished by substituting some heteroatoms for H and substituting sulfur atoms for oxygen in the ether linkages. Use of a new plasticizer to make the etched surface clearer than what has been accomplished as of today is suggested. Possible improvement in acquiring better tracks and increasing the ratio of V sub T/V sub B was planned. This is to be accomplished by changing the composition of the etchants, etching time, and etching temperature.

  4. An advanced SiC nuclear radiation detector

    Microsoft Academic Search

    S. Seshadri; A. R. Dulloo; F. H. Ruddy

    1997-01-01

    This paper reports low noise, high charge collection efficiency, resolution, room temperature, self-biased operation of 3-8 ?m thick, epitaxially grown, SiC Schottky and pn junction diode detectors fabricated on n+ 4H-SiC substrates. These devices are also shown, for the first time, to have a linear gamma ray response. The thin active region used not only eliminates the problems with material

  5. Dosimetric characterization of a synthetic single crystal diamond detector in clinical radiation therapy small photon beams

    SciTech Connect

    Ciancaglioni, I.; Marinelli, Marco; Milani, E.; Prestopino, G.; Verona, C.; Verona-Rinati, G.; Consorti, R.; Petrucci, A.; De Notaristefani, F. [INFN-Dipartimento di Ingegneria Industriale, Universita di Roma 'Tor Vergata',Via del Politecnico 1, I-00133 Roma (Italy); U.O. Fisica Sanitaria, Ospedale San Filippo Neri, Via G. Martinotti 20, 00135 Roma (Italy); INFN-Dipartimento di Fisica, Universita Roma 3, Via della Vasca Navale 84, 00146 Roma (Italy)

    2012-07-15

    Purpose: To determine the potentialities of synthetic single crystal diamond Schottky diodes for accurate dose measurements in radiation therapy small photon beams. Methods: The dosimetric properties of a diamond-based detector were assessed by comparison with a reference microionization chamber. The diamond device was operated at zero bias voltage under irradiation with high-energy radiotherapic photon beams. The stability of the detector response and its dose and dose rate dependence were measured. Different square field sizes ranging from 1 Multiplication-Sign 1 cm{sup 2} to 10 Multiplication-Sign 10 cm{sup 2} were used during comparative dose distribution measurements by means of percentage depth dose curves (PDDs), lateral beam profiles, and output factors. The angular and temperature dependence of the diamond detector response were also studied. Results: The detector response shows a deviation from linearity of less than {+-}0.5% in the 0.01-7 Gy range and dose rate dependence below {+-}0.5% in the 1-6 Gy/min range. PDDs and output factors are in good agreement with those measured by the reference ionization chamber within 1%. No angular dependence is observed by rotating the detector along its axis, while {approx}3.5% maximum difference is measured by varying the radiation incidence angle in the polar direction. The temperature dependence was investigated as well and a {+-}0.2% variation of the detector response is found in the 18-40 Degree-Sign C range. Conclusions: The obtained results indicate the investigated synthetic diamond-based detector as a candidate for small field clinical radiation dosimetry in advanced radiation therapy techniques.

  6. Physical design and Monte Carlo simulations of a space radiation detector onboard the SJ-10 satellite

    NASA Astrophysics Data System (ADS)

    Liu, Ya-Qing; Wang, Huan-Yu; Cui, Xing-Zhu; Peng, Wen-Xi; Fan, Rui-Rui; Liang, Xiao-Hua; Gao, Ming; Zhang, Yun-Long; Zhang, Cheng-Mo; Zhang, Jia-Yu; Yang, Jia-Wei; Wang, Jin-Zhou; Zhang, Fei; Dong, Yi-Fan; Guo, Dong-Ya; Zhou, Da-Wei

    2015-01-01

    A radiation gene box (RGB) onboard the SJ-10 satellite is a device carrying mice and drosophila cells to determine the biological effects of space radiation environment. The shielded fluxes of different radioactive sources were calculated and the linear energy transfers of ?-rays, electrons, protons and ?-particles in the tissue were acquired using A-150 tissue-equivalent plastic. Then, a conceptual model of a space radiation instrument employing three semiconductor sub-detectors for deriving the charged and uncharged radiation environment of the RGB was designed. The energy depositions in the three sub-detectors were classified into 15 channels (bins) in an algorithm derived from the Monte Carlo method. The physical feasibility of the conceptual instrument was also verified by Monte Carlo simulations.

  7. Information-Based Development of New Radiation Detectors

    SciTech Connect

    Ferris, Kim F.; Webb-Robertson, Bobbie-Jo M.; Jones, Dumont M.

    2006-12-31

    With our present concern for a secure environment, the development of new radiation detection materials has focused on the capability of identifying potential radiation sources at increased sensitivity levels. As the initial framework for a materials-informatics approach to radiation detection materials, we have explored the use of both supervised (Support Vector Machines – SVM and Linear Discriminant Analysis – LDA) and unsupervised (Principal Component Analysis – PCA) learning methods for the development of structural signature models. Application of these methods yields complementary results, both of which are necessary to reduce parameter space and variable degeneracy. Using a crystal structure classification test, the use of the nonlinear SVM significantly increases predictive performance, suggesting trade-offs between smaller descriptor spaces and simpler linear models.

  8. Radiation tolerance of epitaxial silicon detectors at very large proton fluences

    Microsoft Academic Search

    G. Lindström; E. Fretwurst; F. Hönniger; G. Kramberger; M. Möller-Ivens; I. Pintilie; A. Schramm

    2006-01-01

    Detectors processed on epitaxial silicon are a promising solution for the extreme radiation levels in the innermost tracking layers at future particle physics experiments as in the upgraded (S-LHC). In order to systematically investigate their radiation tolerance, sets of 25 and 50-?m-thick diodes had been irradiated with 24GeV\\/c protons up to fluences of ?eq=1016cm?2. The full depletion voltage was measured

  9. Comprehensive modeling of bulk-damage effects in silicon radiation detectors

    Microsoft Academic Search

    Daniele Passeri; Paolo Ciampolini; Gian Mario Bilei; Francesco Moscatelli

    2001-01-01

    In this paper, the issue of numerical modeling of radiation-damaged silicon devices is discussed, with reference to radiation detectors employed in high-energy physics experiments. Since the actual physical picture is far too complex to be accounted for at a first-principle (i.e., defect kinetics) level and not yet fully understood, a hierarchical approach has been followed looking for a suitable approximation

  10. Capture of carriers by impurity clouds in germanium nuclear-radiation detectors

    Microsoft Academic Search

    V. V. Voronkov; G. I. Voronkova; S. G. Danengirsh; B. V. Zubov; V. P. Kalinushkin; T. M. Murina; E. A. Petrova; A. M. Prokhorov; N. B. Strokan; O. P. Chikalova-Luzina

    1982-01-01

    A correlation between the intensity of low-angle scattering of COâ laser radiation by impurity clouds of radius a = 6--9 ..mu.. and with an average charge loss factor lambda-bar was observed in nuclear-radiation detectors made of high-purity germanium. The nature of this effect was explained by considering the interaction of an impurity cloud with carriers drifting in the electric field

  11. MOS-transistor radiation detectors and X-ray dose-enhancement effects

    Microsoft Academic Search

    L. D. Posey; T. F. Wrobel; D. C. Evans; W. Beezhold; J. G. Kelly; C. J. MacCallum; F. N. Coppage; T. F. Luera; A. J. Smith

    1985-01-01

    Sandia National Laboratory (SNL) CMOS IC dose detectors and 3N161 MOS Transistors were evaluated as pulsed X-radiation dosimeters and used as monitors to measure dose-enhancement effects. Measurements were made in the photon environments from the HydraMITE II, SPR III, MBS and PITHON radiation sources. The dosimetric evaluation data suggest that the 3N161 MOS transistors are useful dosimeters for measuring flash

  12. MOS-transistor radiation detectors and x-ray dose-enhancement effects

    Microsoft Academic Search

    L. D. Posey; T. F. Wrobel; D. C. Evans; W. Beezhold; J. G. Kelly; C. J. MacCallum; F. N. Coppage; T. F. Luera; A. J. Smith

    1985-01-01

    Sandia National Laboratory (SNL) CMOS IC dose detectors and 3N161 MOS Transistors were evaluated as pulsed x-radiation dosimeters and used as monitors to measure dose-enhancement effects. Measurements were made in the photon environments from the HydraMITE II, SPR III, MBS and PITHON radiation sources. The dosimetric evaluation data suggest that the 3N161 MOS transistors are useful dosimeters for measuring flash

  13. Scintillation fibers and nanoscintillators for improving the spatial, spectrometric, and time resolution of radiation detectors

    Microsoft Academic Search

    N. V. Klassen; V. N. Kurlov; S. N. Rossolenko; O. A. Krivko; A. D. Orlov; S. Z. Shmurak

    2009-01-01

    Experimental examples demonstrate a significant improvement of the most important parameters (sensitivity; spatial, spectrometric,\\u000a and time resolution; and radiation hardness) of radiation detectors with sensitive elements based on fiber and nanocrystalline\\u000a scintillators instead of conventional bulk single crystals. This improvement is related to several specific features of the\\u000a new scintillator types: improved homogeneity of activator distribution, larger soft X-ray component

  14. Applied Radiation and Isotopes 56 (2002) 953956 Sensitivity of LR115 detector in diffusion chamber to 222

    E-print Network

    Yu, K.N.

    Applied Radiation and Isotopes 56 (2002) 953­956 Sensitivity of LR115 detector in diffusion chamber state nuclear track detector (SSNTD), LR115. In use of the cellulose nitrate material LR115, alpha Determination has been made of the sensitivity of LR115 type 2-track detectors (in units of m) to 222 Rn

  15. On the problem of the radiation hardness of SiC nuclear radiation detectors at high working temperatures

    SciTech Connect

    Ivanov, A. M., E-mail: Alexandr.Ivanov@mail.ioffe.ru; Sadokhin, A. V.; Strokan, N. B.; Lebedev, A. A. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation)

    2011-10-15

    Owing to the radiation-induced pronounced conductivity compensation in silicon carbide, carrier localization (trapping) prevails over recombination in capture of nonequilibrium carriers. This makes it possible, by raising the temperature, to reduce the time of carrier retention by a trapping center to values shorter than the duration of signal shaping by electronic circuits. For structural defects created by 6.5-MeV protons, the temperature excluding degradation of the detector signal via carrier localization is estimated. The values of the appearing generation current the noise of which can restrict the operation of a detector in the spectrometric mode are determined.

  16. A Cherenkov Radiation Detector with High Density Aerogels

    E-print Network

    Cremaldi, Lucien; Sonnek, Peter; Summers, Donald J; Reidy, Jim

    2009-01-01

    We have designed a threshold Cherenkov detector at the Rutherford-Appleton Laboratory to identify muons with momenta between 230 and 350 MeV/c. We investigated the properties of three aerogels for the design. The nominal indexes of refraction were n = 1.03, 1.07, 1.12, respectively. Two of the samples are of high density aerogel not commonly used for Cherenkov light detection. We present results of an examination of some optical properties of the aerogel samples and present basic test beam results.

  17. Innovative uses for conventional radiation detectors via pulse shape analysis

    SciTech Connect

    Beckedahl, D; Blair, J; Friensehner, A; Kammeraad, J E; Schmid, G

    1999-03-03

    In this report we have discussed two applications for digital pulse shape analysis in Ge detectors: Compton suppression and {gamma}-ray imaging. The Compton suppression aspect has been thoroughly studied during the past few years, and a real-time, laboratory-prototype system has been fielded. A summary of results from that set up have been discussed here. The {gamma}-ray imaging aspect, while not yet developed experimentally, looks very promising theoretically as the simulations presented here have shown. Experimental work currently underway at Berkeley (as discussed in section 4.3) should help further guide us towards the proper developmental path.

  18. High-efficiency scintillation detector for combined detection of thermal and fast neutrons and gamma radiation

    DOEpatents

    Chiles, M.M.; Mihalczo, J.T.; Blakeman, E.D.

    1987-02-27

    A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation event count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

  19. High-efficiency scintillation detector for combined of thermal and fast neutrons and gamma radiation

    DOEpatents

    Chiles, Marion M. (Knoxville, TN); Mihalczo, John T. (Oak Ridge, TN); Blakeman, Edward D. (Oak Ridge, TN)

    1989-01-01

    A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation even count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

  20. Method and system for determining depth distribution of radiation-emitting material located in a source medium and radiation detector system for use therein

    DOEpatents

    Benke, Roland R. (Helotes, TX); Kearfott, Kimberlee J. (Ann Arbor, MI); McGregor, Douglas S. (Ann Arbor, MI)

    2003-03-04

    A method, system and a radiation detector system for use therein are provided for determining the depth distribution of radiation-emitting material distributed in a source medium, such as a contaminated field, without the need to take samples, such as extensive soil samples, to determine the depth distribution. The system includes a portable detector assembly with an x-ray or gamma-ray detector having a detector axis for detecting the emitted radiation. The radiation may be naturally-emitted by the material, such as gamma-ray-emitting radionuclides, or emitted when the material is struck by other radiation. The assembly also includes a hollow collimator in which the detector is positioned. The collimator causes the emitted radiation to bend toward the detector as rays parallel to the detector axis of the detector. The collimator may be a hollow cylinder positioned so that its central axis is perpendicular to the upper surface of the large area source when positioned thereon. The collimator allows the detector to angularly sample the emitted radiation over many ranges of polar angles. This is done by forming the collimator as a single adjustable collimator or a set of collimator pieces having various possible configurations when connected together. In any one configuration, the collimator allows the detector to detect only the radiation emitted from a selected range of polar angles measured from the detector axis. Adjustment of the collimator or the detector therein enables the detector to detect radiation emitted from a different range of polar angles. The system further includes a signal processor for processing the signals from the detector wherein signals obtained from different ranges of polar angles are processed together to obtain a reconstruction of the radiation-emitting material as a function of depth, assuming, but not limited to, a spatially-uniform depth distribution of the material within each layer. The detector system includes detectors having different properties (sensitivity, energy resolution) which are combined so that excellent spectral information may be obtained along with good determinations of the radiation field as a function of position.

  1. Measurement of thermal radiation using regular glass optics and short-wave infrared detectors.

    PubMed

    Yoon, H W; Eppeldauer, G P

    2008-01-21

    The measurement of thermal radiation from ambient-temperature objects using short-wave infrared detectors and regular glass optics is described. The detectors are chosen to operate in the 2.0 microm to 2.5 microm atmospheric window. Selection of detectors with high shunt resistance along with the 4-stage thermo-electric cooling of the detectors to -85 degrees C results in detectivity, D*, of 4 x 10(13) cm Hz(1/2)/W which is near the background limited performance at 295 K. Furthermore, the use of regular-glass commercial optics to collect the thermal radiation results in diffraction-limited imaging. The use of a radiation thermometer constructed with these elements for the measurement of a blackbody from 20 degrees C to 50 degrees C results in noise-equivalent temperature difference (NETD) of < 3 mK at 50 degrees C. The operation at shorter wavelengths than traditional thermal sensors also leads to lower sensitivity to the emissivity of the object in determining the temperature of the object. These elements are used to construct a calibrator for an infrared collimator, and such a system demonstrates noise-equivalent irradiances of < 5 fW/cm(2). These results indicate that radiometers using short-wave infrared sensors could be constructed utilizing commercial glass optics with possible better performance and lower NETD than existing radiometers using cryogenically-cooled mid-infrared or thermal infrared detectors. PMID:18542168

  2. Spectral and temperature correction of silicon photovoltaic solar radiation detectors

    Microsoft Academic Search

    J. J. Michalsky; R. Perez; L. Harrison; B. A. LeBaron

    1991-01-01

    Silicon photovoltaic sensors are an inexpensive alternative to standard thermopile sensors for the measurement of solar radiation. However, their temperature and spectral response render them less accurate for global horizontal irradiance and unsuitable for direct beam and diffuse horizontal irradiance unless they can be reliably corrected. A correction procedure for the rotating shadowband radiometer, which measures all three components, based

  3. Evaluation of high density DRAMs as a nuclear radiation detector

    Microsoft Academic Search

    H. P. Chou; T. C. Chou; T. H. Hau

    1997-01-01

    The research is based on the nuclear radiation induced soft error phenomenon associated with dynamic random access memory devices (DRAMs). Samples of 256 kbit and 1 Mbit decapped DRAMs from several manufacturers were exposed to standard alpha sources and showed a linear response with an intrinsic detection efficiency approaching 10%. Sensitivity studies were performed to evaluate the effects of DRAM

  4. Scintillation Detectors for Radiation-Hard Electromagnetic Calorimeters

    Microsoft Academic Search

    H. Löhner

    2005-01-01

    For the application in the compact and radiation hard electromagnetic (EM) calorimeter in the PANDA detection system at the new GSI facility, we have started to advance scintillation crystals and the light detection technique. PANDA is the universal internal-target detection system for charmonium spectroscopy and the search for glue-balls and hybrid states in antiproton annihilations. In particular, the large dynamic

  5. Radiation detectors and sources enhanced with micro/nanotechnology

    NASA Astrophysics Data System (ADS)

    Whitney, Chad Michael

    The ongoing threat of nuclear terrorism presents major challenges to maintaining national security. Currently, only a small percentage of the cargo containers that enter America are searched for fissionable bomb making materials. This work reports on a multi-channel radiation detection platform enabled with nanoparticles that is capable of detecting and discriminating all types of radiation emitted from fissionable bomb making materials. Typical Geiger counters are limited to detecting only beta and gamma radiation. The micro-Geiger counter reported here detects all species of radiation including beta particles, gamma/X-rays, alpha particles, and neutrons. The multi-species detecting micro-Geiger counter contains a hermetically sealed and electrically biased fill gas. Impinging radiation interacts with tailored nanoparticles to release secondary charged particles that ionize the fill gas. The ionized particles collect on respectively biased electrodes resulting in a characteristic electrical pulse. Pulse height spectroscopy and radiation energy binning techniques can then be used to analyze the pulses to determine the specific radiation isotope. The ideal voltage range of operation for energy discrimination was found to be in the proportional region at 1000VDC. In this region, specific pulse heights for different radiation species resulted. The amplification region strength which determines the device sensitivity to radiation energy can be tuned with the electrode separation distance. Considerable improvements in count rates were achieved by using the charge conversion nanoparticles with the highest cross sections for particular radiation species. The addition of tungsten nanoparticles to the microGeiger counter enabled the device to be four times more efficient at detecting low level beta particles with a dose rate of 3.2uR/hr (micro-Roentgen per hour) and just under three times more efficient than an off the shelf Geiger counter. The addition of lead nanoparticles enabled the gamma/X-ray microGeiger counter channel to be 28 times more efficient at detecting low level gamma rays with a dose rate of 10uR/hr when compared to a device without nanoparticles. The addition of 10B nanoparticles enabled the neutron microGeiger counter channel to be 17 times more efficient at detecting neutrons. The device achieved a neutron count rate of 9,866 counts per minute when compared to a BF3 tube which resulted in a count rate of 9,000 counts per minute. By using a novel micro-injection ceramic molding and low temperature (950°C) silver paste metallizing process, the batch fabrication of essentially disposable micro-devices can be achieved. This novel fabrication technique was then applied to a MEMS neutron gun and water spectroscopy device that also utilizes the high voltage/temperature insulating packaging.

  6. Preliminary Results from an Investigation into Nanostructured Nuclear Radiation Detectors for Non-Proliferation Applications

    SciTech Connect

    ,

    2012-10-01

    In recent years, the concept of embedding composite scintillators consisting of nanosized inorganic crystals in an organic matrix has been actively pursued. Nanocomposite detectors have the potential to meet many of the homeland security, non-proliferation, and border and cargo-screening needs of the nation and, by virtue of their superior nuclear identification capability over plastic, at roughly the same cost as plastic, have the potential to replace all plastic detectors. Nanocomposites clearly have the potential of being a gamma ray detection material that would be sensitive yet less expensive and easier to produce on a large scale than growing large, whole crystals of similar sensitivity. These detectors would have a broad energy range and a sufficient energy resolution to perform isotopic identification. The material can also be fabricated on an industrial scale, further reducing cost. This investigation focused on designing and fabricating prototype core/shell and quantum dot (QD) detectors. Fourteen core/shell and four QD detectors, all with the basic consistency of a mixture of nanoparticles in a polymer matrix with different densities of nanoparticles, were prepared. Nanoparticles with sizes <10 nm were fabricated, embedded in a polystyrene matrix, and the resultant scintillators’ radiation detector properties were characterized. This work also attempted to extend the gamma energy response on both low- and high-energy regimes by demonstrating the ability to detect low-energy and high-energy gamma rays. Preliminary results of this investigation are consistent with a significant response of these materials to nuclear radiation.

  7. Intercomparison of luminescence detectors for space radiation dosimetry within Proton-ICCHIBAN experiments

    NASA Astrophysics Data System (ADS)

    Uchihori, Yukio; Ploc, Ondrej; Yasuda, Nakahiro; Berger, Thomas; Hajek, Michael; Kodaira, Satoshi; Benton, Eric; Ambrozova, Iva; Kitamura, Hisashi

    2012-07-01

    Luminescence detectors for space radiation dosimetry are frequently used to estimate personal and environmental doses in the International Space Station and other space vehicles. Detector responses for cosmic rays and their secondaries were investigated for a long time and it is well-known that luminescence detectors have dependencies of response on LET (Linear Energy Transfer). Some of luminescence detectors show over-response to gamma rays (used for routine calibration) and others have similar responses to gamma rays. But, because of lack of sufficient and reliable calibration data in the low LET region (about 1 keV/?m), it is the responses of these detectors at LET is poorly known. Protons make up the dominant portion of the fluence from space radiation, so the LET region corresponding to energetic protons must be characterized very well. For that purpose, calibration and intercomparison experiments were performed using relatively low energy (30 to 80 MeV) proton beams at the National Institute of Radiological Sciences, Chiba, Japan. In this paper, the results of these intercomparison experiments, including high energy protons and light ions, are reported and illustrate the response of luminescence detectors in the low LET region. This research will help improve our understanding of space dosimeters and reliable dose measurement for astronauts and cosmonauts in low earth orbit.

  8. Optimum Design of DACs for Threshold Correction in Multichannel Processors for Radiation Detectors

    Microsoft Academic Search

    Lodovico Ratti; Alessia Manazza

    2012-01-01

    This work is intended to provide a set of guidelines for the design of digital-to-analog converters enabling the reduction of threshold dispersion in multichannel readout circuits for radiation detectors. The design criteria are first established through a theoretical approach and then confirmed by means of a simulation tool based on Monte Carlo methods. This latter tool provides a fast and

  9. Performance of CdZnTe geometrically weighted semiconductor Frisch grid radiation detectors

    Microsoft Academic Search

    D. S. McGregor; R. A. Rojeski

    1999-01-01

    Semiconductor Frisch grid radiation detectors have been manufactured and tested with encouraging results. Resolution enhancement occurs as a result of combining the geometric weighting effect, the “small pixel” effect and the Frisch grid effect. The devices are operated at ambient temperature without any pulse shape correction, rejection and compensation techniques. The new devices are manufactured from CdZnTe and do not

  10. Spacecraft to Spacecraft Coherent Laser Tracking as a Xylophone Interferometer Detector of Gravitational Radiation

    NASA Technical Reports Server (NTRS)

    Tinto, M.

    1998-01-01

    Searches for gravitational radiation can be performed in space with two spacecraft tracking each other with coherent laser light. This experimental technique could be implemented with two spacecraft carrying an appropriate optical payload, or with the proposed broad-band, space-based laser interferometer detectors of gravitational waves operated in this non-interferometric mode.

  11. Influence of zone purification process on TlBr crystals for radiation detector fabrication

    Microsoft Academic Search

    Keitaro Hitomi; Toshiyuki Onodera; Tadayoshi Shoji

    2007-01-01

    Thallium bromide (TlBr) is a wide gap compound semiconductor and is a promising material for fabrication of nuclear radiation detectors. In this study, the conventional zone refining method was employed to reduce the concentration of impurities in the TlBr crystals. In order to evaluate the efficiency of the zone purification, the zone purification process was repeated up to 300 times.

  12. Recent Results Obtained with High Field, Internally Amplifying Semiconductor Radiation Detectors

    Microsoft Academic Search

    Gerald C. Huth

    1966-01-01

    Characterization of the gallium diffused junctions found useful as amplifying radiation detectors indicate a rather surprising window-junction depth relationship. The window, at only the self bias of the junction, has been measured to be a micron or so although the junction depth is ~50 microns. This is a result of the unusual diffusion process used - diffusion to 75 microns

  13. A new thermal radiation detector using optical heterodyne detection of absorbed energy

    NASA Technical Reports Server (NTRS)

    Davis, C. C.; Petuchowski, S. J.

    1983-01-01

    The operating principles of a new kind of room-temperature thermal radiation detector are described. In this device modulated light heats a gas, either directly or by conduction from a thin absorbing membrane, and the resultant change in density of the gas is detected by optical heterodyning. The performance of a membrane device of this kind agrees well with the predictions of theory.

  14. Developing Si(Li) nuclear radiation detectors by pulsed electric field treatment

    Microsoft Academic Search

    R. A. Muminov; S. A. Radzhapov; A. K. Saimbetov

    2009-01-01

    Fabrication of Si(Li) nuclear radiation detectors using lithium ion drift under the action of a pulsed electric field is considered. Optimum treatment regime parameters are determined, including the pulse amplitude, duration, and repetition rate. Experimental data are presented, which show that the ion drift in a pulsed electric field decreases the semiconductor bulk compensation time by a factor of two

  15. Simple method for measuring the energy equivalent of the noise of semiconductor nuclear radiation detectors

    Microsoft Academic Search

    O. V. Zakharchuk; A. A. Ilin

    1973-01-01

    Translated from Prib. Tekn. Eksp.; 16: No. 4, 75-77(1973). A method ; is considered for determining the energy equivalent of the noise of semiconductor ; nuclear-radiation detectors which is based on calibrating a simplified ; measurement device consisting solely of a spectrometric preamplifier and a vacuum-; tube voltmeter. The method allows a considerable increase in the speed of the ;

  16. Using Ionizing Radiation Detectors. Module 11. Vocational Education Training in Environmental Health Sciences.

    ERIC Educational Resources Information Center

    Consumer Dynamics Inc., Rockville, MD.

    This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on using ionizing radiation detectors. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) naming and telling the function…

  17. Low-cost cadmium zinc telluride radiation detectors based on electron-transport-only designs

    SciTech Connect

    B. A. Brunett; J. C. Lund; J. M. Van Scyoc; N. R. Hilton; E. Y. Lee; R. B. James

    1999-01-01

    The goal of this project was to utilize a novel device design to build a compact, high resolution, room temperature operated semiconductor gamma ray sensor. This sensor was constructed from a cadmium zinc telluride (CZT) crystal. It was able to both detect total radiation intensity and perform spectroscopy on the detected radiation. CZT detectors produced today have excellent electron charge carrier collection, but suffer from poor hole collection. For conventional gamma-ray spectrometers, both the electrons and holes must be collected with high efficiency to preserve energy resolution. The requirement to collect the hole carriers, which have relatively low lifetimes, limits the efficiency and performance of existing experimental devices. By implementing novel device designs such that the devices rely only on the electron signal for energy information, the sensitivity of the sensors for detecting radiation can be increased substantially. In this report the authors describe a project to develop a new type of electron-only CZT detector. They report on their successful efforts to design, implement and test these new radiation detectors. In addition to the design and construction of the sensors the authors also report, in considerable detail, on the electrical characteristics of the CZT crystals used to make their detectors.

  18. An Electronically-collimated Gamma-ray Detector for Localization of Radiation Sources

    Microsoft Academic Search

    Blair Smith; Kenneth L. Matthews II; Adam Lackie; W. H. Hill; Wei-Hsung Wang; M. L. Cherry

    2006-01-01

    Small hand-held radiation detectors that can image a gamma-ray source and yet can be transported by a single operator could have numerous applications, either in medical intraoperative procedures or in nuclear security field work. We report on the design of a device intended for such applications and we present results of simulations that indicate expected performance for such a compact

  19. Investigations on radiation hardness of DEPFET sensors for the Belle II detector

    NASA Astrophysics Data System (ADS)

    Ritter, Andreas; Andricek, Ladislav; Kleinohl, Tobias; Koffmane, Christian; Lütticke, Florian; Marinas, Carlos; Moser, Hans-Günther; Ninkovic, Jelena; Richter, Rainer; Schaller, Gerhard; Schnecke, Martina; Schopper, Florian

    2013-12-01

    In the upgrade of the Belle detector at KEK (Tsukuba, Japan) the two innermost layers of the vertex detector will be realized by a pixel detector (PXD) consisting of DEPFET (DEpleted P-channel Field Effect Transistor) matrices. As the position of the detector will be very close to the beam pipe, it will suffer from intense radiation levels. The main radiation background is the luminosity related 4-fermion final state radiation, which damages the silicon bulk material and the silicon dioxide from the gate contacts. With the dose expected at Belle II, the DEPFET suffers mainly from additional leakage current and increase in noise. In addition, defects in the silicon dioxide change transistor parameters, e.g. the threshold voltage. We will show results on the hardness factor of electrons after a 10 MeV electron irradiation which was performed in the dose and energy range relevant for the PXD. In addition, we present X-ray irradiations of DEPFET equivalent test structures and compare radiation hardness for different oxide parameters in the prototype production.

  20. Applied Radiation and Isotopes 62 (2005) 631634 Peripheral dose measurement with a MOSFET detector

    E-print Network

    Yu, K.N.

    2005-01-01

    Applied Radiation and Isotopes 62 (2005) 631­634 Peripheral dose measurement with a MOSFET detector September 2004; accepted 8 September 2004 Abstract The accuracy of a MOSFET dosimetry system with respect, the MOSFET system in the high-sensitivity mode produces reproducibility of dose measurement with relative

  1. THE AMS-02 TRANSITION RADIATION DETECTOR FOR THE INTERNATIONAL SPACE STATION

    E-print Network

    Roma "La Sapienza", Università di

    1 THE AMS-02 TRANSITION RADIATION DETECTOR FOR THE INTERNATIONAL SPACE STATION A. BARTOLONI I The Alpha Magnetic Spectrometer (AMS-02) is a large experiment in the International Space Station (ISS on the International Space Station (ISS) to measure primary cosmic ray spectra in space [1]. A key element for dark

  2. Calibration of a VUV spectrometer-detector system using synchrotron radiation

    Microsoft Academic Search

    A. McPherson; N. Rouze; W. B. Westerveld; J. S. Risley

    1986-01-01

    Synchrotron light is presently used as the primary intensity standard for the calibration of the detection efficiency of a VUV spectrometer detector system, in a novel apparatus for the measurement of absolute electron impact photoemission cross sections in the 30-150 nm range. By scanning the beam of synchrotron radiation across the surface of the spectrometer grating, a precise simulation of

  3. Silicon field-effect transistors as radiation detectors for the Sub-THz range

    SciTech Connect

    But, D. B., E-mail: but.dmitry@gmail.com; Golenkov, O. G.; Sakhno, N. V.; Sizov, F. F.; Korinets, S. V.; Gumenjuk-Sichevska, J. V.; Reva, V. P.; Bunchuk, S. G. [National Academy of Sciences of Ukraine, Lashkaryov Institute of Semiconductor Physics (Ukraine)

    2012-05-15

    The nonresonance response of silicon metal-oxide-semiconductor field-effect transistors (Si-MOSFETs) with a long channel (1-20 {mu}m) to radiation in the frequency range 43-135 GHz is studied. The transistors are fabricated by the standard CMOS technology with 1-{mu}m design rules. The volt-watt sensitivity and the noise equivalent power (NEP) for such detectors are estimated with the calculated effective area of the detecting element taken into account. It is shown that such transistors can operate at room temperature as broadband direct detectors of sub-THz radiation. In the 4-5 mm range of wavelengths, the volt-watt sensitivity can be as high as tens of kV/W and the NEP can amount to 10{sup -11} - 10{sup -12}W/{radical}Hz . The parameters of detectors under study can be improved by the optimization of planar antennas.

  4. Dichroic filters to protect milliwatt far-infrared detectors from megawatt ECRH radiation.

    PubMed

    Bertschinger, G; Endres, C P; Lewen, F; Oosterbeek, J W

    2008-10-01

    Dichroic filters have been used to shield effectively the far infrared (FIR) detectors at the interferometer/polarimeter on TEXTOR. The filters consist of metal foils with regular holes, the hole diameter, the mutual spacing and the thickness of the foils are chosen to transmit radiation at the design frequency with transmission >90%. The attenuation at the low frequency end of the bandpass filter is about 30 dB per octave, the high frequency transmission is between 20% and 40%. The filters have been used to block the stray radiation from the megawatt microwave heating beam to the detectors of the FIR interferometer, operating with power on the detector in the milliwatt range. If required, the low frequency attenuation can be still enhanced, without compromising the transmission in the passband. The FIR interferometer used for plasma density and position control is no longer disturbed by electromagnetic waves used for plasma heating. PMID:19044527

  5. Detectors

    DOEpatents

    Orr, Christopher Henry (Calderbridge, GB); Luff, Craig Janson (Calderbridge, GB); Dockray, Thomas (Calderbridge, GB); Macarthur, Duncan Whittemore (Los Alamos, NM); Bounds, John Alan (Los Alamos, NM); Allander, Krag (Los Alamos, NM)

    2002-01-01

    The apparatus and method provide techniques through which both alpha and beta emission determinations can be made simultaneously using a simple detector structure. The technique uses a beta detector covered in an electrically conducting material, the electrically conducting material discharging ions generated by alpha emissions, and as a consequence providing a measure of those alpha emissions. The technique also offers improved mountings for alpha detectors and other forms of detectors against vibration and the consequential effects vibration has on measurement accuracy.

  6. EFFECT OF SURFACE PREPARATION TECHNIQUE ON THE RADIATION DETECTOR PERFORMANCEOF CDZNTE

    SciTech Connect

    Duff, M

    2007-05-23

    Synthetic CdZnTe (CZT) semiconducting crystals are highly suitable for the room temperature-based detection of gamma radiation. The surface preparation of Au contacts on surfaces of CZT detectors is typically conducted after (1) polishing to remove artifacts from crystal sectioning and (2) chemical etching, which removes residual mechanical surface damage however etching results in a Te rich surface layer that is prone to oxidize. Our studies show that CZT surfaces that are only polished (as opposed to polished and etched) can be contacted with Au and will yield lower surface currents. Due to their decreased dark currents, these as-polished surfaces can be used in the fabrication of gamma detectors exhibiting a higher performance than polished and etched surfaces with relatively less peak tailing and greater energy resolution. CdZnTe or ''CZT'' crystals are attractive to use in homeland security applications because they detect radiation at room temperature and do not require low temperature cooling as with silicon- and germanium-based detectors. Relative to germanium and silicon detectors, CZT is composed of higher Z elements and has a higher density, which gives it greater ''stopping power'' for gamma rays making a more efficient detector. Single crystal CZT materials with high bulk resistivity ({rho}>10{sup 10} {Omega} x cm) and good mobility-lifetime products are also required for gamma-ray spectrometric applications. However, several factors affect the detector performance of CZT are inherent to the as grown crystal material such as the presence of secondary phases, point defects and the presence of impurities (as described in a literature review by R. James and researchers). These and other factors can limit radiation detector performance such as low resistivity, which causes a large electronic noise and the presence of traps and other heterogeneities, which result in peak tailing and poor energy resolution.

  7. Weakly superconducting, thin-film structures as radiation detectors.

    NASA Technical Reports Server (NTRS)

    Kirschman, R. K.

    1972-01-01

    Measurements were taken with weakly superconducting quantum structures of the Notarys-Mercereau type, representing a thin superconductor film with a short region that is weakened in the sense that its transition temperature is lower than in the remaining portion of the film. The structure acts as a superconducting relaxation oscillator in which the supercurrent increases with time until the critical current of the weakened section is attained, at which moment the supercurrent decays and the cycle repeats. Under applied radiation, a series of constant-voltage steps appears in the current-voltage curve, and the size of the steps varies periodically with the amplitude of applied radiation. Measurements of the response characteristics were made in the frequency range of 10 to 450 MHz.

  8. Quantum limits on resonant-mass gravitational-radiation detectors

    Microsoft Academic Search

    James Hollenhorst

    1979-01-01

    The methods of quantum detection theory are applied to a resonant-mass gravitational-radiation antenna. Quantum sensitivity limits are found which depend strongly on the quantum state in which the antenna is prepared. Optimum decision strategies and their corresponding sensitivities are derived for some important initial states. The linear detection limit (E\\/sub min\\/ approx. h..omega..) is shown to apply when the antenna

  9. Digital configurable instrument for emulation of signals from radiation detectors

    SciTech Connect

    Abba, A.; Caponio, F.; Geraci, A. [Politecnico di Milano, Department of Electronics, Information and Bioengineering-DEIB, Milan 20133 (Italy)] [Politecnico di Milano, Department of Electronics, Information and Bioengineering-DEIB, Milan 20133 (Italy)

    2014-01-15

    The paper presents a digital instrument characterized by a specially designed architecture that is able to emulate in real time signals from a generic radiation detection system. The instrument is not a pulse generator of recorded shapes but a synthesizer of random pulses compliant to programmable statistics for height and starting time of events. Completely programmable procedures for emulation of noise, disturbances, and reference level variation are implemented.

  10. Characterisation of vertical gradient freeze semi-insulating InP for use as a nuclear radiation detector

    Microsoft Academic Search

    H. El-Abbassi; S. Rath; P. J. Sellin

    2001-01-01

    The performance of a nuclear radiation detector fabricated from Vertical Gradient Freeze (VGF) semi-insulating Fe-doped InP was investigated. Pulse height spectra were acquired when the detector was irradiated with alpha particles from 241Am, as a function of temperature and detector bias voltage. The spectroscopic performance of the detector was limited at room temperature due to the presence of a high

  11. Simulation Studies of Delta-ray Backgrounds in a Compton-Scatter Transition Radiation Detector

    E-print Network

    Krizmanic, J F; Streitmatter, R E; Krizmanic, John F.; Cherry, Michael L.; Streitmatter, Robert E.

    2006-01-01

    In order to evaluate the response to cosmic-ray nuclei of a Compton-Scatter Transition Radiation Detector in the proposed ACCESS space-based mission, a hybrid Monte Carlo simulation using GEANT3 and an external transition radiation (TR) generator routine was constructed. This simulation was employed to study the effects of delta-ray production induced by high-energy nuclei and to maximize the ratio of TR to delta-ray background. The results demonstrate the ability of a Compton-Scatter Transition Radiation Detector to measure nuclei from boron to iron up to Lorentz factors ~ 10^5 taking into account the steeply falling power-law cosmic ray spectra.

  12. Evaluation of high density DRAMs as a nuclear radiation detector.

    PubMed

    Chou, H P; Chou, T C; Hau, T H

    1997-01-01

    The research is based on the nuclear radiation induced soft error phenomenon associated with dynamic random access memory devices (DRAMs). Samples of 256 kbit and 1 Mbit decapped DRAMs from several manufactures were exposed to standard alpha sources and showed a linear response with an intrinsic detection efficiency approaching 10%. Sensitivity studies were performed to evaluate the effects of DRAM operating voltage, refresh frequency and the data pattern stored prior to irradiation. The associated mechanism of soft error phenomenon is discussed. Samples were also exposed to gamma rays up to 10(5) rad to examine the total dose effect. The annealing phenomenon after gamma exposure is also presented. PMID:9463880

  13. Development of an alpha/beta/gamma detector for radiation monitoring

    SciTech Connect

    Yamamoto, Seiichi [Kobe City College of Technology, 8-3, Gakuen-Higashi-machi, Nishi-ku, Kobe, 651-2194 (Japan); Hatazawa, Jun [Osaka University of Graduate School of Medicine, 2-2, Yamadaoka, Suita-shi, Osaka, 565-0871 (Japan)

    2011-11-15

    For radiation monitoring at the site of nuclear power plant accidents such as Fukushima Daiichi, radiation detectors not only for gamma photons but also for alpha and beta particles are needed because some nuclear fission products emit beta particles and gamma photons and some nuclear fuels contain plutonium that emits alpha particles. We developed a radiation detector that can simultaneously monitor alpha and beta particles and gamma photons for radiation monitoring. The detector consists of three-layered scintillators optically coupled to each other and coupled to a photomultiplier tube. The first layer, which is made of a thin plastic scintillator (decay time: 2.4 ns), detects alpha particles. The second layer, which is made of a thin Gd{sub 2}SiO{sub 5} (GSO) scintillator with 1.5 mol.% Ce (decay time: 35 ns), detects beta particles. The third layer made of a thin GSO scintillator with 0.4 mol.% Ce (decay time: 70 ns) detects gamma photons. By using pulse shape discrimination, the count rates of these layers can be separated. With individual irradiation of alpha and beta particles and gamma photons, the count rate of the first layer represented the alpha particles, the second layer represented the beta particles, and the third layer represented the gamma photons. Even with simultaneous irradiation of the alpha and beta particles and the gamma photons, these three types of radiation can be individually monitored using correction for the gamma detection efficiency of the second and third layers. Our developed alpha, beta, and gamma detector is simple and will be useful for radiation monitoring, especially at nuclear power plant accident sites or other applications where the simultaneous measurements of alpha and beta particles and gamma photons are required.

  14. Regional myocardial radiotracer kinetics in dogs using miniature radiation detectors.

    PubMed

    Jacobs, M L; Okada, R D; Daggett, W M; Fowler, B N; Strauss, H W; Geffin, G; Pohost, G M

    1982-05-01

    An implantable device for continuous measurement of regional myocardial radioisotope activity was designed and validated. The probe consists of a 2-mm3 cadmium telluride crystal surrounded by lead foil housed in a 4.5-mm outer diameter steel cylinder. Activity in serial dilutions of thallium-201 measured by this miniature gamma detector correlated well with activity measured in the well counter (r = 0.99). In vivo probe measurements of regional myocardial thallium-201 activity in a canine model were compared with activity in punch biopsies, again with excellent correlation (r = 0.90). The crystal was mounted on a modified arterial clamp, which was inserted into the left ventricle through, the apex and situated on the endocardial surface of the anterior or posterior wall. It was thus possible to measure regional isotope activity without excessive background from the blood pool and opposite heart wall. The probe was found best suited for monitoring activities of isotopes with energies between 60 and 250 keV. With a pair of these devices, dynamic studies of the myocardial kinetics of radioisotopes such as thallium-201 in normal and ischemic myocardium are now possible. PMID:7081457

  15. The AMS-02 transition radiation detector (TRD) gas control system

    NASA Astrophysics Data System (ADS)

    Bartoloni, Alessandro

    2004-02-01

    The Alpha Magnetic Spectrometer (AMS-02) is a large experiment in the International Space Station (ISS) intended to measure primary cosmic ray spectra in space. It sits outside of the station, looking out into space. High-energy particles pass through it, interacting with different detectors on the way. They all travel at about the speed of light, so the TOF and the RICH cannot distinguish them. The TRD, thought, is sensitive to = E/ m, the energy divided by the mass. This quantity is very different for electrons and protons so the TRD can tell them apart. In particular this is important for dark-matter search, for which we need a good signature for positrons. To reach its physics goals a TRD was designed to identify positrons with a rejection factor of 10 3 against protons from 1.5 to 300 GeV. The gas control system of the TRD is an essential item for its performance. To obtain the required discriminating power, a stringent control of gas parameters is necessary.

  16. Effects of Te inclusions on the performance of CdZnTe radiation detectors

    SciTech Connect

    Bolotnikov,A.E.; Abdul-Jabber, N. M.; Babalola, O. S.; Camarda, G. S.; Cui, Y.; Hossain, A. M.; Jackson, E. M.; Jackson, H. C.; James, J. A.; Kohman, K. T.; Luryi, A. L.; James, R. B.

    2008-10-19

    Te inclusions existing at high concentrations in CdZnTe (CZT) material can degrade the performance of CZT detectors. These microscopic defects trap the free electrons generated by incident radiation, so entailing significant fluctuations in the total collected charge and thereby strongly affecting the energy resolution of thick (long-drift) detectors. Such effects were demonstrated in thin planar detectors, and, in many cases, they proved to be the dominant cause of the low performance of thick detectors, wherein the fluctuations in the charge losses accumulate along the charge's drift path. We continued studying this effect using different tools and techniques. We employed a dedicated beamline recently established at BNL's National Synchrotron Light Source for characterizing semiconductor radiation detectors, along with an IR transmission microscope system, the combination of which allowed us to correlate the concentration of defects with the devices performances. We present here our new results from testing over 50 CZT samples grown by different techniques. Our goals are to establish tolerable limits on the size and concentrations of these detrimental Te inclusions in CZT material, and to provide feedback to crystal growers to reduce their numbers in the material.

  17. Electrically calibrated pyroelectric detector for high-accuracy calibration of UV radiation

    NASA Astrophysics Data System (ADS)

    Shao, Xiumei; Ding, Jieying; Yu, Yuehua; Fang, Jiaxiong

    2008-03-01

    A pyroelectric detector with special structure was developed for calibration of UV radiation. A new relaxor-based ferroelectric single crystal with high pyroelectric coefficient was selected as the detector material. The detector is free of substrate and a black coating film was deposited on the surface of the sensitive area. The reflectance of the coating film is less than 1% in the spectral range 200nm to 400nm, and its sheet resistance is near 100 Ohm. Both the UV radiation absorption and the electrically heating in the coating film can result in temperature change. Accordingly, the film can work both as optical absorber and electric heater. By this means, the measurement of UV radiation power can be converted to the measurement of electrical power. The direction of the heat flow is same in both cases, but the mechanism of heat transport has tiny differences. A finite element model was set up by ANSYS software to simulate the thermal diffusivity. The factors which may bring errors to the optical-electrical equivalence were measured and analyzed in detail. The detectors were used to establish UV electrically calibrated system with uncertainty less than 4% in the spectral range from 200nm to 400nm at room temperature.

  18. Prototype Radiation Detector Positioning System For The Automated Nondestructive Assay Of Uf6 Cylinders

    SciTech Connect

    Hatchell, Brian K.; Valdez, Patrick LJ; Orton, Christopher R.; Mace, Emily K.

    2011-08-07

    International Atomic Energy Agency (IAEA) inspectors currently perform periodic inspections at uranium enrichment plants to verify UF6 cylinder enrichment declarations. Measurements are typically performed with handheld high-resolution sensors on a sampling of cylinders taken to be representative of the facility’s entire cylinder inventory. These measurements are time-consuming, expensive, and assay only a small fraction of the total cylinder volume. An automated nondestructive assay system capable of providing enrichment measurements over the full volume of the cylinder could improve upon current verification practices in terms of efficiency and assay accuracy. This paper describes an approach denoted the Integrated Cylinder Verification Station (ICVS) that supports 100% cylinder verification, provides volume-averaged cylinder enrichment assay, and reduces inspector manpower needs. To allow field measurements to be collected to validate data collection algorithms, a prototype radiation detector positioning system was constructed. The system was designed to accurately position an array of radiation detectors along the length of a cylinder to measure UF6 enrichment. A number of alternative radiation shields for the detectors were included with the system. A collimated gamma-ray spectrometer module that allows translation of the detectors in the surrounding shielding to adjust the field of view, and a collimating plug in the end to further reduce the low-energy field of view, were also developed. Proof-of-principle measurements of neutron and high-energy gamma-ray signatures, using moderated neutron detectors and large-volume spectrometers in a fixed-geometry, portal-like configuration, supported an early assessment of the viability of the concept. The system has been used successfully on two testing campaigns at an AREVA fuel fabrication plant to scan over 30 product cylinders. This paper will describe the overall design of the detector positioning system and provide an overview of the Integrated Cylinder Verification Station (ICVS) approach.

  19. The simulation of the LANFOS-H food radiation contamination detector using Geant4 package

    NASA Astrophysics Data System (ADS)

    Piotrowski, Lech Wiktor; Casolino, Marco; Ebisuzaki, Toshikazu; Higashide, Kazuhiro

    2015-02-01

    Recent incident in the Fukushima power plant caused a growing concern about the radiation contamination and resulted in lowering the Japanese limits for the permitted amount of 137Cs in food to 100 Bq/kg. To increase safety and ease the concern we are developing LANFOS (Large Food Non-destructive Area Sampler)-a compact, easy to use detector for assessment of radiation in food. Described in this paper LANFOS-H has a 4 ? coverage to assess the amount of 137Cs present, separating it from the possible 40K food contamination. Therefore, food samples do not have to be pre-processed prior to a test and can be consumed after measurements. It is designed for use by non-professionals in homes and small institutions such as schools, showing safety of the samples, but can be also utilized by specialists providing radiation spectrum. Proper assessment of radiation in food in the apparatus requires estimation of the ? conversion factor of the detectors-how many ? photons will produce a signal. In this paper we show results of the Monte Carlo estimation of this factor for various approximated shapes of fish, vegetables and amounts of rice, performed with Geant4 package. We find that the conversion factor combined from all the detectors is similar for all food types and is around 37%, varying maximally by 5% with sample length, much less than for individual detectors. The different inclinations and positions of samples in the detector introduce uncertainty of 1.4%. This small uncertainty validates the concept of a 4 ? non-destructive apparatus.

  20. A Leakage Current-based Measurement of the Radiation Damage in the ATLAS Pixel Detector

    E-print Network

    The ATLAS collaboration

    2014-01-01

    A measurement has been made of the radiation damage incurred by the ATLAS Pixel Detector barrel silicon modules from the beginning of operations through the end of 2012. This translates to hadronic fluence received over the full period of operation at energies up to and including 8 TeV. The measurement is based on a per-module measurement of the silicon sensor leakage current. The results are presented as a function of integrated luminosity and compared to predictions by the Hamburg Model. This information can be used to predict the lifetime of the Pixel Detector for various operating scenarios.

  1. A Leakage Current-based Measurement of the Radiation Damage in the ATLAS Pixel Detector

    E-print Network

    Gorelov, Igor; The ATLAS collaboration

    2014-01-01

    A measurement has been made of the radiation damage incurred by the ATLAS Pixel Detector barrel silicon modules from the beginning of operations through the end of 2012. This translates to hadronic fluence received over the full period of operation at energies up to and including 8 TeV. The measurement is based on a per-module measurement of the silicon sensor leakage current. The results are presented as a function of integrated luminosity and compared to predictions by the Hamburg Model. This information can be used to predict limits on the lifetime of the Pixel Detector due to current, for various operating scenarios.

  2. Laser instrumentation for one-phonon sensitivity and wide bandwidth with multimode gravitational radiation detectors

    SciTech Connect

    Richard, J.

    1988-08-15

    In a multimode detector of gravitational radiation, the displacements induced in the antenna by the gravitational field can be amplified by many orders at the last resonator. Detection of the displacements of that resonator with a Fabry--Perot interferometer is considered. Quantum and classical sources of noise are analyzed and specifications for laser instrumented massive wideband systems operating at the level of deltah = 2.6 x 10/sup -20/ and 3 x 10/sup -22//(Hz)/sup 1/2/ are given. Three detectors could be used to cover the frequency range approx. =400--approx. =1200 Hz with approximately uniform sensitivity.

  3. Gamma spectroscopic measurements using the PID350 pixelated CdTe radiation detector

    E-print Network

    K. Karafasoulis; K. Zachariadou; S. Seferlis; I. Papadakis; D. Loukas; C. Lambropoulos; C. Potiriadis

    2010-11-15

    Spectroscopic measurements are presented using the PID350 pixelated gamma radiation detectors. A high-speed data acquisition system has been developed in order to reduce the data loss during the data reading in case of a high flux of photons. A data analysis framework has been developed in order to improve the resolution of the acquired energy spectra, using specific calibration parameters for each PID350's pixel. Three PID350 detectors have been used to construct a stacked prototype system and spectroscopic measurements have been performed in order to test the ability of the prototype to localize radioactive sources.

  4. Earth radiation budget measurement from a spinning satellite: Conceptual design of detectors

    NASA Technical Reports Server (NTRS)

    Sromovsky, L. A.; Revercomb, H. E.; Suomi, V. E.

    1975-01-01

    The conceptual design, sensor characteristics, sensor performance and accuracy, and spacecraft and orbital requirements for a spinning wide-field-of-view earth energy budget detector were investigated. The scientific requirements for measurement of the earth's radiative energy budget are presented. Other topics discussed include the observing system concept, solar constant radiometer design, plane flux wide FOV sensor design, fast active cavity theory, fast active cavity design and error analysis, thermopile detectors as an alternative, pre-flight and in-flight calibration plane, system error summary, and interface requirements.

  5. Initial Field Measurements with the Multisensor Airborne Radiation Survey (MARS) High Purity Germanium (HPGe) Detector Array

    SciTech Connect

    Fast, James E.; Bonebrake, Christopher A.; Dorow, Kevin E.; Glasgow, Brian D.; Jensen, Jeffrey L.; Morris, Scott J.; Orrell, John L.; Pitts, W. Karl; Rohrer, John S.; Todd, Lindsay C.

    2010-06-29

    Abstract: The Multi-sensor Airborne Radiation Survey (MARS) project has developed a new single cryostat detector array design for high purity germanium (HPGe) gamma ray spectrometers that achieves the high detection efficiency required for stand-off detection and actionable characterization of radiological threats. This approach is necessary since a high efficiency HPGe detector can only be built as an array due to limitations in growing large germanium crystals. The system is ruggedized and shock mounted for use in a variety of field applications. This paper reports on results from initial field measurements conducted in a truck and on two different boats.

  6. A Leakage Current-based Measurement of the Radiation Damage in the ATLAS Pixel Detector

    E-print Network

    Igor V. Gorelov; for the ATLAS Collaboration

    2015-02-12

    A measurement has been made of the radiation damage incurred by the ATLAS Pixel Detector barrel silicon modules from the beginning of operations through the end of 2012. This translates to hadronic fluence received over the full period of operation at energies up to and including 8 TeV. The measurement is based on a per-module measurement of the silicon sensor leakage current. The results are presented as a function of integrated luminosity and compared to predictions by the Hamburg Model. This information can be used to predict limits on the lifetime of the Pixel Detector due to current, for various operating scenarios.

  7. Evidence for field enhanced electron capture by EL2 centers in semi-insulating GaAs and the effect on GaAs radiation detectors

    E-print Network

    Terry, Fred L.

    on GaAs radiation detectors Douglas S. McGregor, a) Ronald A. Rojeski, and Glenn F. Knoll Department semiconductor radiation detectors fabricated from semi-insulating GaAs is highly sensitive to charged impurities with experimental alpha particle pulse height measurements. I. INTRODUCTION Schottky contact radiation detectors

  8. arXiv:0707.4642v1[cond-mat.mtrl-sci]31Jul2007 Subnanosecond Ellipticity Detector for Laser Radiation

    E-print Network

    Ganichev, Sergey

    temperature detector of terahertz laser radiation ellipticity has been developed based on the simultaneous detector elements in response to laser radiation. The first element provides information about, including visible, in this paper we present the detector for terahertz (THz) laser radiation

  9. Radiation damage effects on detectors and eletronic devices in harsh radiation environment

    E-print Network

    Fiore, S

    2015-01-01

    Radiation damage effects represent one of the limits for technologies to be used in harsh radiation environments as space, radiotherapy treatment, high-energy phisics colliders. Different technologies have known tolerances to different radiation fields and should be taken into account to avoid unexpected failures which may lead to unrecoverable damages to scientific missions or patient health.

  10. Super-Cerenkov Radiation: A new phenomenon useful for RICH Detectors

    E-print Network

    D. B. Ion; M. L. Ion

    2004-12-11

    In this contribution the Super-Cerenkov radiation (SCR) as a new phenomenon which includes in a more general and exact form the usual Cerenkov effect is presented. The Super-Cerenkov effect at Cerenkov threshold in the radiators of RICH detectors is investigated. The results on the experimental test of the super- Cerenkov coherence conditions are presented. The SCR-predictions are verified experimentally with high accuracy chi/n_{dof}=1.47 by the data on the Cerenkov ring radii of electron, muon, pion and kaon, all measured with RICH detector. Moreover, it is shown that the Super-Cerenkov phenomenon can explain not only subthreshold CR but also the observed secondary rings (or anomalous Cerenkov radiation) observed at CERN SPS accelerator. The influence of medium on the particle propagation properties is also estimated and the refractive properties of electrons, muons, pions, in the radiator C4F10Ar are obtained. So, we proved that the refractive indices of the charged elementary particles in medium are also very important for the RICH detectors, especially at low and intermediate energies.

  11. Evaluation of radiation interference in the Voyager Sun Sensor's cadmium sulfide detector

    NASA Technical Reports Server (NTRS)

    Clarke, T. C.; Divita, E. L.

    1978-01-01

    The simulation of radiation interference effects and the results of a radiation interference test on two Voyager Sun Sensor prototype detector assemblies are reported. The derivation of test levels and requirements are discussed and show that cobalt 60 gamma radiation is an effective and practical simulator of the ionization dose rate effects induced by high-energy electron flux incident on the spacecraft at a rate of 3.7 x 10 to the 8th e/sq cm-sec (10 rad(Si)/s) during closest approach to Jupiter. The test results provide information that is used to confirm an analytic correlation, and to predict satisfactory performance of a spacecraft sun sensing device having stringent angular resolution requirements. The measured detector response shows that at dose rates incident on the detector elements of 2 rad(Si)/sec, which is four times that expected during Jupiter encounter, the radiation-induced angle error is almost an order of magnitude less than that allowed by the acceptance criteria.

  12. Electrodrift purification of materials for room temperature radiation detectors

    DOEpatents

    James, Ralph B. (5420 Lenore Ave., Livermore, Alameda County, CA 94550); Van Scyoc, III, John M. (P.O. Box 93, 65 Main St., Apt. 1, Plainfield, Cumberland County, PA 17081); Schlesinger, Tuviah E. (8 Carleton Dr., Mt. Lebanon, Allegheny County, PA 15243)

    1997-06-24

    A method of purifying nonmetallic, crystalline semiconducting materials useful for room temperature radiation detecting devices by applying an electric field across the material. The present invention discloses a simple technology for producing purified ionic semiconducting materials, in particular PbI.sub.2 and preferably HgI.sub.2, which produces high yields of purified product, requires minimal handling of the material thereby reducing the possibility of introducing or reintroducing impurities into the material, is easy to control, is highly selective for impurities, retains the stoichiometry of the material and employs neither high temperatures nor hazardous materials such as solvents or liquid metals. An electric field is applied to a bulk sample of the material causing impurities present in the sample to drift in a preferred direction. After all of the impurities have been transported to the ends of the sample the current flowing through the sample, a measure of the rate of transport of mobile impurities, falls to a low, steady state value, at which time the end sections of the sample where the impurities have concentrated are removed leaving a bulk sample of higher purity material. Because the method disclosed here only acts on the electrically active impurities, the stoichiometry of the host material remains substantially unaffected.

  13. Electrodrift purification of materials for room temperature radiation detectors

    DOEpatents

    James, R.B.; Van Scyoc, J.M. III; Schlesinger, T.E.

    1997-06-24

    A method of purifying nonmetallic, crystalline semiconducting materials useful for room temperature radiation detecting devices by applying an electric field across the material is disclosed. The present invention discloses a simple technology for producing purified ionic semiconducting materials, in particular PbI{sub 2} and preferably HgI{sub 2}, which produces high yields of purified product, requires minimal handling of the material thereby reducing the possibility of introducing or reintroducing impurities into the material, is easy to control, is highly selective for impurities, retains the stoichiometry of the material and employs neither high temperatures nor hazardous materials such as solvents or liquid metals. An electric field is applied to a bulk sample of the material causing impurities present in the sample to drift in a preferred direction. After all of the impurities have been transported to the ends of the sample the current flowing through the sample, a measure of the rate of transport of mobile impurities, falls to a low, steady state value, at which time the end sections of the sample where the impurities have concentrated are removed leaving a bulk sample of higher purity material. Because the method disclosed here only acts on the electrically active impurities, the stoichiometry of the host material remains substantially unaffected. 4 figs.

  14. Gamma-ray CdTe and CdZnTe detectors: investigations and applications in radiation control devices

    NASA Astrophysics Data System (ADS)

    Korbutyak, Dmytro V.; Krylyuk, Sergiy G.; Kryuchenko, Yurii V.; Kupchak, Igor; Komar, Vitaliy K.; Nalivaiko, Dmitriy; Smuk, Rostyslav; Storonskii, Yurii

    2001-12-01

    In this paper we present results of our investigations on the technology improvement for high-grade CdTe and CdZnTe single-crystals growth as well as results of the obtained materials testing by photoluminescence method. Perspectives for the materials utilization in detectors and devices of radiation control are discussed. Design features and characteristics of the developed personal (gamma) - and X-radiation dosimeters on the base of CdTe detectors and (gamma) -radiation spectrometers on the base of CdZnTe detectors are presented and discussed as well.

  15. A high spatial resolution computerized electro-optic radiation detector array

    SciTech Connect

    Kearfott, K.J.; Murty, K.N. (Georgia Institute of Technology, Atlanta (USA))

    1990-01-01

    A novel computerized electro-optic detector was designed, constructed, and characterized. The results of the experiments performed were as follows: (1) To obtain a maximum SNR when operating at any radiation intensity, the designed detector must be operated at the lowest temperature-- -5 degrees C in this configuration. This temperature permits a maximum integration time of 9.7 s without signal distortion. (2) The detector was found to be linear in the range of operation studied, 2.8 X 10(-3) to 2.0 X 10(-2) C kg-1 h-1 (11-78 R h-1), with a sensitivity of 4.2 X 10(4) mV per C kg-1 h-1 (10.8 mV per R h-1). (3) A simulated stepped phantom was imaged, illustrating the possibility of positional measurements. (4) Very little blooming was noticed.

  16. Coherent sychrotron radiation detector for a non-invasive subpicosecond bunch length monitor

    SciTech Connect

    Krafft, G.A.; Wang, D.; Price, E.; Feldl, E. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Porterfield, D.; Wood, P.; Crowe, T. [Virginia Univ., Charlottesville, VA (United States)

    1995-12-31

    This CSR detector was developed to monitor nondestructively the length of a subpicosecond bunch with high sensitivity. The monitor uses a state of the art GaAs Schottky whisker diode which is operated at room temperature at a wavelength of a few hundred microns. The detector is capable of detecting radiation power as low as 10 nW, depending on wavelength. This paper describes design specifications, parameter ranges, and monitor features and also reports its performance and comparison between measurement and calculation. The measurement results are cross-compared with an independent bunch length measurement using phase modulation. It was found that the output power varies with bunch length and that detectors at shorter wavelengths are preferred.

  17. The performance and radiation hardness of the Outer Tracker detector for LHCb

    NASA Astrophysics Data System (ADS)

    Gersabeck, E.

    2014-06-01

    The LHCb experiment is designed to study B and D-meson decays at the LHC, in the forward region. It is crucial to accurately and efficiently detect the charged decay particles in the high-density particle environment of the LHC. For this, the Outer Tracker (OT) has been constructed. The detector has operated reliably under the challenging LHC conditions in 2011 and 2012. The performance of the detector is discussed in terms of high voltage stability, noise rate and single hit efficiency. New results on the hit resolution are presented. Finally, latest results on the radiation tolerance of this sensitive gas detector are discussed, after having received a total dose corresponding to about 100 mC/cm in the hottest region, and having operated with proton-ion collisions in 2013.

  18. Single-detector searches for a stochastic background of gravitational radiation

    E-print Network

    Massimo Tinto; J. W. Armstrong

    2012-05-21

    We propose a data processing technique that allows searches for a stochastic background of gravitational radiation with data from a single detector. Our technique exploits the difference between the coherence time of the gravitational wave (GW) signal and that of the instrumental noise affecting the measurements. By estimating the auto-correlation function of the data at an off-set time that is longer than the coherence time of the noise {\\underbar {but}} shorter than the coherence time of the GW signal, we can effectively enhance the power signal-to-noise ratio (SNR) by the square-root of the integration time. The resulting SNR is comparable in magnitude to that achievable by cross-correlating the data from two co-located and co-aligned detectors whose noises are uncorrelated. Our method is general and it can be applied to data from ground- and space-based detectors, as well as from pulsar timing experiments.

  19. Measurement of the energy spectrum of underground muons at Gran Sasso with a transition radiation detector

    E-print Network

    The MACRO Collaboration; M. Ambrosio et al

    1998-07-09

    We have measured directly the residual energy of cosmic ray muons crossing the MACRO detector at the Gran Sasso Laboratory. For this measurement we have used a transition radiation detector consisting of three identical modules, each of about 12 m^2 area, operating in the energy region from 100 GeV to 1 TeV. The results presented here were obtained with the first module collecting data for more than two years. The average single muon energy is found to be 320 +/- 4 (stat.) +/- 11 (syst.) GeV in the rock depth range 3000-6500 hg/cm^2. The results are in agreement with calculations of the energy loss of muons in the rock above the detector.

  20. Single crystal chemical vapor deposited diamond detectors for intensity-modulated radiation therapy applications

    SciTech Connect

    Rebisz-Pomorska, M.; Tromson, D.; Bergonzo, P. [CEA, LIST, Diamond Sensors Laboratory, F-91191 Gif-sur-Yvette (France); Isambert, A. [Institut Gustave Roussy (IGR), 94805 Villejuif (France); Marczewska, B. [Institute of Nuclear Physics, Polish Academy of Sciences (IFJ PAN), 31-342 Krakow (Poland)

    2009-10-15

    We report here on first intensity-modulated radiation therapy (IMRT) clinical tests performed at the Gustave Roussy Institute in France using one small (0.117 mm{sup 3}) synthetic single crystal diamond detector (SCDD). We report the comparison between the point doses evaluated with our detector, with a PTW semiflex air ionization chamber (0.125 cm{sup 3}) and calculated with the treatment planning system (TPS), respectively. The obtained results show a maximum difference of 2.3% for the diamond detector and of 4.6% for the ionization chamber, as compared with the TPS calculations. These very promising results show the potentiality of chemical vapor deposited SCDD for dosimetry of IMRT fields and opens up the field for diamond dosimeters toward novel applications such as very small beam monitoring.

  1. Current-driven detection of terahertz radiation using a dual-grating-gate plasmonic detector

    SciTech Connect

    Boubanga-Tombet, S., E-mail: stephanealbon@hotmail.com; Tanimoto, Y.; Satou, A.; Suemitsu, T.; Otsuji, T. [Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai 980-8577 (Japan); Wang, Y.; Minamide, H.; Ito, H. [RIKEN Sendai, 519-1399 Aramaki Aoba, Aoba-ku, Sendai 980-0845 (Japan); Fateev, D. V.; Popov, V. V. [Kotelnikov Institute of Radio Engineering and Electronics (Saratov Branch), 410019 Saratov (Russian Federation); Saratov State University, 410012 Saratov (Russian Federation)

    2014-06-30

    We report on the detection of terahertz radiation by an on-chip planar asymmetric plasmonic structure in the frequency region above one terahertz. The detector is based on a field-effect transistor that has a dual grating gate structure with an asymmetric unit cell, which provides a geometrical asymmetry within the structure. Biasing the detector with a dc source-to-drain current in the linear region of the current-voltage characteristic introduces an additional asymmetry (electrical asymmetry) that enhances the detector responsivity by more than one order of magnitude (by a factor of 20) as compared with the unbiased case due to the cooperative effect of the geometrical and electrical asymmetries. In addition to the responsivity enhancement, we report a relatively low noise equivalent power and a peculiar non-monotonic dependence of the responsivity on the frequency, which results from the multi-plasmonic-cavity structure of the device.

  2. Development of CdTe pixel detector for synchrotron radiation experiments

    NASA Astrophysics Data System (ADS)

    Hirono, T.; Toyokawa, H.; Furukawa, Y.; Kawase, M.; Ohata, T.; Wu, S.; Ikeda, H.; Sato, G.; Takahashi, T.; Watanabe, S.

    2013-12-01

    This study describes the development of a CdTe pixel detector for high-energy X-ray diffraction experiments at synchrotron radiation facilities. We have developed three prototypes. The third prototype detector (SP8-02B) was designed with a pixel size of 200 ?m×200 ?m and a matrix of 20×50 pixels. The sensor was bonded to an application-specific integrated circuit with a preamplifier, shaper, window-type discriminator, and a 20-bit counter for each pixel. The SP8-02B detector improved the uniformity between pixels in one chip in comparison with the previous prototypes. The long-term stability was measured at various temperatures. A moderate cooling achieved good stability that was not affected by the polarization effect.

  3. Deconvolving the temporal response of photoelectric x-ray detectors for the diagnosis of pulsed radiations

    NASA Astrophysics Data System (ADS)

    Zou, Shiyang; Song, Peng; Guo, Liang; Pei, Wenbing

    2013-09-01

    Based on the conjugate gradient method, a simple algorithm is presented for deconvolving the temporal response of photoelectric x-ray detectors (XRDs) to reconstruct the resolved time-dependent x-ray fluxes. With this algorithm, we have studied the impact of temporal response of XRD on the radiation diagnosis of hohlraum heated by a short intense laser pulse. It is found that the limiting temporal response of XRD not only postpones the rising edge and peak position of x-ray pulses but also smoothes the possible fluctuations of radiation fluxes. Without a proper consideration of the temporal response of XRD, the measured radiation flux can be largely misinterpreted for radiation pulses of a hohlraum heated by short or shaped laser pulses.

  4. Radiation-damage studies, irradiations and high-dose dosimetry for LHC detectors

    E-print Network

    Coninckx, F; León-Florián, E; Leutz, H; Schönbacher, Helmut; Sonderegger, P; Tavlet, Marc; Sopko, B; Henschel, H; Schmidt, H U; Boden, A; Bräunig, D; Wulf, F; Cramariuc, R; Ilie, D; Fattibene, P; Onori, S; Miljanic, S; Paic, G; Razen, B; Razem, D; Rendic, D; CERN. Geneva. Detector Research and Development Committee

    1991-01-01

    The proposal is divided into a main project and special projects. The main project consists of a service similar to the one given in the past to accelerator construction projects at CERN (ISR,SPS,LEP) on high-dose dosimetry, material irradiations, irradiations tests, standardization of test procedures and data compilations. Large experience in this field and numerous radiation damage test data of insulating and structural materials are available. The special projects cover three topics which are of specific interest for LHC detector physicists and engineers at CERN and in other high energy physics institutes, namely: Radiation effects in scintillators; Selection of radiation hard optical fibres for data transmission; and Selection and testing of radiation hard electronic components.

  5. Micro-Fabricated Solid-State Radiation Detectors for Active Personal Dosimetry

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Wrbanek, Susan Y.; Fralick, Gustave C.; Chen, Liang-Yu

    2007-01-01

    Active radiation dosimetry is important to human health and equipment functionality for space applications outside the protective environment of a space station or vehicle. This is especially true for long duration missions to the moon, where the lack of a magnetic field offers no protection from space radiation to those on extravehicular activities. In order to improve functionality, durability and reliability of radiation dosimeters for future NASA lunar missions, single crystal silicon carbide devices and scintillating fiber detectors are currently being investigated for applications in advanced extravehicular systems. For many years, NASA Glenn Research Center has led significant efforts in silicon carbide semiconductor technology research and instrumentation research for sensor applications under extreme conditions. This report summarizes the technical progress and accomplishments toward characterization of radiation-sensing components for the recommendation of their fitness for advanced dosimetry development.

  6. Deconvolving the temporal response of photoelectric x-ray detectors for the diagnosis of pulsed radiations

    SciTech Connect

    Zou, Shiyang; Song, Peng; Pei, Wenbing [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)] [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Guo, Liang [Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-986, Mianyang 621900 (China)] [Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-986, Mianyang 621900 (China)

    2013-09-15

    Based on the conjugate gradient method, a simple algorithm is presented for deconvolving the temporal response of photoelectric x-ray detectors (XRDs) to reconstruct the resolved time-dependent x-ray fluxes. With this algorithm, we have studied the impact of temporal response of XRD on the radiation diagnosis of hohlraum heated by a short intense laser pulse. It is found that the limiting temporal response of XRD not only postpones the rising edge and peak position of x-ray pulses but also smoothes the possible fluctuations of radiation fluxes. Without a proper consideration of the temporal response of XRD, the measured radiation flux can be largely misinterpreted for radiation pulses of a hohlraum heated by short or shaped laser pulses.

  7. Determination of tolerances of mirror displacement and radiator gas impurity for the CBM RICH detector

    NASA Astrophysics Data System (ADS)

    Adamczewski-Musch, J.; Becker, K.-H.; Belogurov, S.; Boldyreva, N.; Chernogorov, A.; Deveaux, C.; Dobyrn, V.; Dürr, M.; Eom, J.; Eschke, J.; Höhne, C.; Kampert, K.-H.; Kleipa, V.; Kochenda, L.; Kolb, B.; Kopfer, J.; Kravtsov, P.; Lebedev, S.; Lebedeva, E.; Leonova, E.; Linev, S.; Mahmoud, T.; Michel, J.; Miftakhov, N.; Nam, Y.; Niebur, W.; Oh, K.; Ovcharenko, E.; Pauly, C.; Pouryamout, J.; Querchfeld, S.; Rautenberg, J.; Reinecke, S.; Riabov, Y.; Roshchin, E.; Samsonov, V.; Song, J.; Tarasenkova, O.; Torres de Heidenreich, T.; Traxler, M.; Ugur, C.; Vznuzdaev, E.; Vznuzdaev, M.; Yi, J.; Yoo, I.-K.

    2014-12-01

    The CBM experiment at the future FAIR facility will explore nuclear matter at high net-baryon densities. One of the key observables is di-leptons as they penetrate the created matter without further strong interactions. A gaseous RICH detector in a standard projective geometry using spherical mirrors is one of two detector elements for the required electron identification. The mirror system consists of about 72 trapezoidal mirror tiles. Any misalignment between the tiles relative to the nominal common spherical surface leads to reduction of the reconstruction efficiency of Cherenkov rings and deterioration of their resolution. To determine tolerances in mirror misalignment extensive simulation and measurement studies were carried out. Pure CO2 will be used as radiator gas. Gas contamination, mainly moisture and Oxygen, reduces the number of detected photons per ring and worsens the quality of reconstructed Cherenkov rings. Therefore a study was carried out to determine tolerances in radiator gas contamination.

  8. Infrared response measurements on radiation-damaged Si/Li/ detectors.

    NASA Technical Reports Server (NTRS)

    Sher, A. H.; Liu, Y. M.; Keery, W. J.

    1972-01-01

    The improved infrared response (IRR) technique has been used to qualitatively compare radiation effects on Si(Li) detectors with energy levels reported for silicon in the literature. Measurements have been made on five commercial silicon detectors and one fabricated in-house, both before and after irradiation with fast neutrons, 1.9-MeV protons, and 1.6-MeV electrons. Effects dependent upon the extent of radiation damage have been observed. It seems likely that the photo-EMF, or photo-voltage, effect is the basic mechanism for the observation of IRR in p-i-n diodes with a wide i-region. Experimental characteristics of the IRR measurement are in agreement with those of the photovoltage effect.

  9. The SNAP 27 gamma radiation spectrum obtained with a Ge/Li/ detector

    NASA Technical Reports Server (NTRS)

    Taherzadeh, M.

    1976-01-01

    The pulse height distribution, obtained experimentally using a Ge(Li) detector, was employed to determine the photon emission rate characteristic of a PuO2 fuel source known as the SNAP 27 heat source. The selfshielding parameters of the photon emitter, the efficiency of the detector and the geometry of the experiment were utilized to determine the unscattered photon emission rate of the source and the unscattered flux spectrum at a certain specified distance from the source. For the scattered part of the flux spectrum a Monte Carlo technique was employed so that the total flux spectrum could be determined at any point in the radiation field. As a result of this work, a technique was developed to obtain the unfolded radiation spectrum of the SNAP 27 heat source.

  10. Radiation-hard ASICs for optical data transmission in the ATLAS pixel detector

    E-print Network

    K. K. Gan

    2003-03-13

    We have developed two radiation-hard ASICs for optical data transmission in the ATLAS pixel detector at the LHC at CERN: a driver chip for a Vertical Cavity Surface Emitting Laser (VCSEL) diode for 80 Mbit/s data transmission from the detector, and a Bi-Phase Mark decoder chip to recover the control data and 40 MHz clock received optically by a PIN diode. We have successfully implemented both ASICs in 0.25 um CMOS technology using enclosed layout transistors and guard rings for increased radiation hardness. We present results from prototype circuits and from irradiation studies with 24 GeV protons up to 57 Mrad (1.9 x 10e15 p/cm2).

  11. A 2D DNA lattice as an ultrasensitive detector for beta radiations.

    PubMed

    Dugasani, Sreekantha Reddy; Kim, Jang Ah; Kim, Byeonghoon; Joshirao, Pranav; Gnapareddy, Bramaramba; Vyas, Chirag; Kim, Taesung; Park, Sung Ha; Manchanda, Vijay

    2014-02-26

    There is growing demand for the development of efficient ultrasensitive radiation detectors to monitor the doses administered to individuals during therapeutic nuclear medicine which is often based on radiopharmaceuticals, especially those involving beta emitters. Recently biological materials are used in sensors in the nanobio disciplines due to their abilities to detect specific target materials or sites. Artificially designed two-dimensional (2D) DNA lattices grown on a substrate were analyzed after exposure to pure beta emitters, (90)Sr-(90)Y. We studied the Raman spectra and reflected intensities of DNA lattices at various distances from the source with different exposure times. Although beta particles have very low linear energy transfer values, the significant physical and chemical changes observed throughout the extremely thin, ?0.6 nm, DNA lattices suggested the feasibility of using them to develop ultrasensitive detectors of beta radiations. PMID:24476415

  12. Development of a new radiation detector utilizing carbon nanotube as anode

    NASA Astrophysics Data System (ADS)

    Kotani, T.; Ueno, M.; Kawai, N.; Kitamoto, S.

    2007-12-01

    A new gas-multiplication radiation detector utilizing carbon nanotube (CNT) as anode is proposed. With CNT anode, a very compact radiation counter with a good spatial resolution might be built. Two test chambers have been built and are being tested. Each detector body, a chamber with a volume of 100 cm-3, is purged of air beforehand and then supplied with argon gas. At room temperature, the chamber works as a traditional proportional counter filled with argon gas. The chamber can be dipped in an open bath of liquid argon (LAr) and cooled to the vapor point of argon, 87 K. Within 1 h of deposition, the chamber will be filled with LAr. The background noise has been reduced to a level that the charge produced by 60 keV photons from 241Am is successfully detected, although a gas-multiplication around CNT is not yet confirmed.

  13. Comparison of direct normal irradiance derived from silicon and thermopile global hemispherical radiation detectors

    NASA Astrophysics Data System (ADS)

    Myers, Daryl R.

    2010-08-01

    Concentrating solar applications utilize direct normal irradiance (DNI) radiation, a measurement rarely available. The solar concentrator industry has begun to deploy numerous measurement stations to prospect for suitable system deployment sites. Rotating shadowband radiometers (RSR) using silicon photodiodes as detectors are typically deployed. This paper compares direct beam estimates from RSR to a total hemispherical measuring radiometer (SPN1) multiple fast thermopiles. These detectors simultaneously measure total and diffuse radiation from which DNI can be computed. Both the SPN1 and RSR-derived DNI are compared to DNI measured with thermopile pyrheliometers. Our comparison shows that the SPN1 radiometer DNI estimated uncertainty is somewhat greater than, and on the same order as, the RSR DNI estimates for DNI magnitudes useful to concentrator technologies.

  14. Comparison of Direct Normal Irradiance Derived from Silicon and Thermopile Global Hemispherical Radiation Detectors: Preprint

    SciTech Connect

    Myers, D. R.

    2010-01-01

    Concentrating solar applications utilize direct normal irradiance (DNI) radiation, a measurement rarely available. The solar concentrator industry has begun to deploy numerous measurement stations to prospect for suitable system deployment sites. Rotating shadowband radiometers (RSR) using silicon photodiodes as detectors are typically deployed. This paper compares direct beam estimates from RSR to a total hemispherical measuring radiometer (SPN1) multiple fast thermopiles. These detectors simultaneously measure total and diffuse radiation from which DNI can be computed. Both the SPN1 and RSR-derived DNI are compared to DNI measured with thermopile pyrheliometers. Our comparison shows that the SPN1 radiometer DNI estimated uncertainty is somewhat greater than, and on the same order as, the RSR DNI estimates for DNI magnitudes useful to concentrator technologies.

  15. Temperature dependence of the radiation induced change of depletion voltage in silicon PIN detectors

    SciTech Connect

    Ziock, H.J.; Holzscheiter, K.; Morgan, A.; Palounek, A.P.T. [Los Alamos National Lab., NM (United States); Ellison, J.; Heinson, A.P.; Mason, M.; Wimpenny, S.J. [Univ. of California, Riverside, CA (United States); Barberis, E.; Cartiglia, N.; Grillo, A.; O`Shaughnessy, K.; Rahn, J.; Rinaldi, P.; Rowe, W.A.; Sadrozinski, H.F.W.; Seiden, A.; Spencer, E.; Webster, A.; Wichmann, R.; Wilder, M. [Univ. of California, Santa Cruz, CA (United States). Santa Cruz Inst. for Particle Physics; Frautschi, M.A.; Matthews, J.A.J.; McDonald, D.; Skinner, D. [Univ. of New Mexico, Albuquerque, NM (United States); Coupal, D.; Pal, T. [Superconducting Super Collider Lab., Dallas, TX (United States)

    1993-11-01

    The silicon microstrip detectors that will be used in the SDC experiment at the Superconducting Super Collider (SSC) will be exposed to very large fluences of charged particles, neutrons, and gammas. The authors present a study of how temperature affects the change in the depletion voltage of silicon PIN detectors damaged by radiation. They study the initial radiation damage and the short-term and long-term annealing of that damage as a function of temperature in the range from {minus}10{degrees}C to +50{degrees}C, and as a function of 800 MeV proton fluence up to 1.5 {times} 10{sup 14} p/cm{sup 2}. They express the pronounced temperature dependencies in a simple model in terms of two annealing time constants which depend exponentially on the temperature.

  16. Signal and noise of Diamond Pixel Detectors at High Radiation Fluences

    E-print Network

    Jieh-Wen Tsung; Miroslav Havranek; Fabian Hügging; Harris Kagan; Hans Krüger; Norbert Wermes

    2012-08-13

    CVD diamond is an attractive material option for LHC vertex detectors because of its strong radiation-hardness causal to its large band gap and strong lattice. In particular, pixel detectors operating close to the interaction point profit from tiny leakage currents and small pixel capacitances of diamond resulting in low noise figures when compared to silicon. On the other hand, the charge signal from traversing high energy particles is smaller in diamond than in silicon by a factor of about 2.2. Therefore, a quantitative determination of the signal-to-noise ratio (S/N) of diamond in comparison with silicon at fluences in excess of 10$^{15}$ n$_{eq}$ cm$^{-2}$, which are expected for the LHC upgrade, is important. Based on measurements of irradiated diamond sensors and the FE-I4 pixel readout chip design, we determine the signal and the noise of diamond pixel detectors irradiated with high particle fluences. To characterize the effect of the radiation damage on the materials and the signal decrease, the change of the mean free path $\\lambda_{e/h}$ of the charge carriers is determined as a function of irradiation fluence. We make use of the FE-I4 pixel chip developed for ATLAS upgrades to realistically estimate the expected noise figures: the expected leakage current at a given fluence is taken from calibrated calculations and the pixel capacitance is measured using a purposely developed chip (PixCap). We compare the resulting S/N figures with those for planar silicon pixel detectors using published charge loss measurements and the same extrapolation methods as for diamond. It is shown that the expected S/N of a diamond pixel detector with pixel pitches typical for LHC, exceeds that of planar silicon pixels at fluences beyond 10$^{15}$ particles cm$^{-2}$, the exact value only depending on the maximum operation voltage assumed for irradiated silicon pixel detectors.

  17. Radiation detector using a bulk high T[sub c] superconductor

    DOEpatents

    Artuso, J.F.; Franks, L.A.; Hull, K.L.; Symko, O.G.

    1993-12-07

    A radiation detector is provided, wherein a bulk high T[sub c] superconducting sample is placed in a magnetic field and maintained at a superconducting temperature. Photons of incident radiation will cause localized heating in superconducting loops of the sample destroying trapped flux and redistributing the fluxons, and reducing the critical current of the loops. Subsequent cooling of the sample in the magnetic field will cause trapped flux redistributed Abrikosov fluxons and trapped Josephson fluxons. The destruction and trapping of the fluxons causes changes in the magnetization of the sample inducing currents in opposite directions in a pickup coil which is coupled by an input coil to an rf SQUID. 4 figures.

  18. Cosmic radiation dose in aircraft--a neutron track etch detector.

    PubMed

    Vukovi?, B; Radoli?, V; Miklavci?, I; Poje, M; Varga, M; Planini?, J

    2007-01-01

    Cosmic radiation bombards us at high altitude by ionizing particles. The radiation environment is a complex mixture of charged particles of solar and galactic origin, as well as of secondary particles produced in interaction of the galactic cosmic particles with the nuclei of atmosphere of the Earth. The radiation field at aircraft altitude consists of different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The non-neutron component of cosmic radiation dose aboard ATR 42 and A 320 aircrafts (flight level of 8 and 11 km, respectively) was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter. The estimated occupational effective dose for the aircraft crew (A 320) working 500 h per year was 1.64 mSv. Other experiments, or dose rate measurements with the neutron dosimeter, consisting of LR-115 track detector and boron foil BN-1 or 10B converter, were performed on five intercontinental flights. Comparison of the dose rates of the non-neutron component (low LET) and the neutron one (high LET) of the radiation field at the aircraft flight level showed that the neutron component carried about 50% of the total dose. The dose rate measurements on the flights from the Middle Europe to the South and Middle America, then to Korea and Japan, showed that the flights over or near the equator region carried less dose rate; this was in accordance with the known geomagnetic latitude effect. PMID:17600597

  19. Charged Particle Measurements on Mars and during Cruise with the Radiation Assessment Detector (MSL/RAD)

    NASA Astrophysics Data System (ADS)

    Ehresmann, B.; Hassler, D.; Zeitlin, C. J.; Wimmer-Schweingruber, R. F.; Appel, J. K.; Brinza, D.; Burmeister, S.; Boehm, E.; Boettcher, S.; Guo, J.; Kohler, J.; Lohf, H.; Martin-Garcia, C.; Rafkin, S. C.; Reitz, G.

    2013-12-01

    The Radiation Assessment Detector (RAD), part of the Mars Science Laboratory (MSL), has been successfully measuring the energetic particle radiation on the Martian surface since the landing of the Curiosity rover in Gale crater. Furthermore, RAD was already operating for large parts of the ~250-day cruise to Mars, measuring the radiation environment inside the spacecraft. Detailed knowledge of particle-type-dependent energy spectra is important for several reasons. E.g., for one measured differential particle fluxes can be used to validate and evaluate transport models currently used to estimate the radiation exposure on the Martian surface. Another important point of knowing the energy spectra of individual ion species is their differing biological effectiveness in terms of assessing radiation exposure risks for future manned missions to Mars. Here, we will present differential fluxes for different ion species, both for the cruise and the surface phase. As the energy range of these spectra is limited by the maximum energy with that a particle can stop in one of RAD's detectors, we will show integral fluxes for energies above these upper limits where the total energy of the detected particle is not known.

  20. High-speed, multi-channel detector readout electronics for fast radiation detectors

    SciTech Connect

    Hennig, Wolfgang

    2012-06-22

    In this project, we are developing a high speed digital spectrometer that a) captures detector waveforms at rates up to 500 MSPS b) has upgraded event data acquisition with additional data buffers for zero dead time operation c) moves energy calculations to the FPGA to increase spectrometer throughput in fast scintillator applications d) uses a streamlined architecture and high speed data interface for even faster readout to the host PC These features are in addition to the standard functions in our existing spectrometers such as digitization, programmable trigger and energy filters, pileup inspection, data acquisition with energy and time stamps, MCA histograms, and run statistics. In Phase I, we upgraded one of our existing spectrometer designs to demonstrate the key principle of fast waveform capture using a 500 MSPS, 12 bit ADC and a Xilinx Virtex-4 FPGA. This upgraded spectrometer, named P500, performed well in initial tests of energy resolution, pulse shape analysis, and timing measurements, thus achieving item (a) above. In Phase II, we are revising the P500 to build a commercial prototype with the improvements listed in items (b)-(d). As described in the previous report, two devices were built to pursue this goal, named the Pixie-500 and the Pixie-500 Express. The Pixie-500 has only minor improvements from the Phase I prototype and is intended as an early commercial product (its production and part of its development were funded outside the SBIR). It also allows testing of the ADC performance in real applications.The Pixie-500 Express (or Pixie-500e) includes all of the improvements (b)-(d). At the end of Phase II of the project, we have tested and debugged the hardware, firmware and software of the Pixie-500 Express prototype boards delivered 12/3/2010. This proved substantially more complex than anticipated. At the time of writing, all hardware bugs have been fixed, the PCI Express interface is working, the SDRAM has been successfully tested and the SHARC DSP has been booted with preliminary code. All new ICs and circuitry on the prototype are working properly, however some of the planned firmware and software functions have not yet been completely implemented and debugged. Overall, due to the unanticipated complexity of the PCI Express interface, some aspects of the project could not be completed with the time and funds available in Phase II. These aspects will be completed in self-funded Phase III.

  1. Radiation damage effects on X- and gamma-ray N+NPP+ silicon detectors

    Microsoft Academic Search

    V. Cimpoca; M. Petris; R. Ruscu; R. Moraru; M. Breten; M. Cimpoca

    1997-01-01

    The paper describes some results concerning technology and behaviour of Xand gamma-ray N+PP+ silicon detectors used in physics research, industrial and medical radiography, and non-destructive testing. Devices manufactured under this technology proved to be stable after an exposure in high intensity gamma field with the dose range of 10 krad-5 Mrad. Nuclear radiation resistance was studied by irradiation with 60Co

  2. A low noise FET with integrated charge restoration for radiation detectors

    Microsoft Academic Search

    T. Nashoishibi; G. White

    1990-01-01

    A novel pulsed, nonoptical, reset technique for use in charge-sensitive amplifiers and radiation detectors is described. The first-stage FET and charge restoration are integrated into one five-terminal device called the Pentafet. A pulse of minority carriers is injected directly into the channel of the FET. The technique is fast, and there are no aftereffects on the operation of the FET.

  3. Silicon PIN radiation detectors with on-chip front-end junction field effect transistors

    Microsoft Academic Search

    G. F. Dalla Betta; G. Verzellesi; M. Boscardin; L. Bosisio; G. U. Pignatel; L. Ferrario; M. Zen; G. Soncini

    1998-01-01

    We report on the latest results obtained from the development of a fabrication technology for PIN radiation detectors with on-chip front-end junction field effect transistors (JFETs) integrated on high-resistivity, FZ silicon. P-doped polysilicon back-side gettering prevented carrier lifetime degradation in spite of the relatively high thermal budget characterizing the fabrication process, allowing very low leakage currents (?1nA\\/cm2 at full depletion)

  4. Effect of surface preparation technique on the radiation detector performance of CdZnTe

    Microsoft Academic Search

    M. C. Duff; D. B. Hunter; A. Burger; M. Groza; V. Buliga; D. R. Black

    2008-01-01

    Synthetic CdZnTe (CZT) semiconducting crystals are highly suitable for the room temperature-based detection of gamma radiation. The surface preparation of Au contacts on surfaces of CZT detectors is typically conducted after (1) polishing to remove artifacts from crystal sectioning and (2) chemical etching, which removes residual mechanical surface damage however etching results in a Te rich surface layer that is

  5. Developing Si(Li) nuclear radiation detectors by pulsed electric field treatment

    Microsoft Academic Search

    R. A. Muminov; S. A. Radzhapov; A. K. Saimbetov

    2009-01-01

    Fabrication of Si(Li) nuclear radiation detectors using lithium ion drift under the action of a pulsed electric field is considered.\\u000a Optimum treatment regime parameters are determined, including the pulse amplitude, duration, and repetition rate. Experimental\\u000a data are presented, which show that the ion drift in a pulsed electric field decreases the semiconductor bulk compensation\\u000a time by a factor of two

  6. Performance of lead iodide nuclear radiation detectors with the introduction of rare earth elements

    Microsoft Academic Search

    Mahmoud Hassan; Marie Matuchova; Karel Zdansky

    2006-01-01

    Lead iodide has been recognized as a promising material for room temperature radiation detectors. It has a wide band-gap (?\\u000a 2.3 eV), high atomic numbers (82, 53) and it is environmentally very stable compared to mercuric iodide. Electrical and optical\\u000a properties of lead iodide grown crystals purified under the influence of selected rare earth elements have been investigated.\\u000a Photo-luminescence and

  7. Study of the radiation hardness of CsI(Tl) crystals for the BELLE detector

    Microsoft Academic Search

    K. Kazui; A. Watanabe; S. Osone; B. G Cheon; M. Fukushima; H. Hayashii; X. Q Hu; S. Ichizawa; S. Igarashi; H. Ikeda; K. Kaneyuki; M. H Lee; K. Miyabayashi; S. Noguchi; H. Sagawa; A. Satpathy; R. Suzuki; K. Tamai; T. Tsukamoto; Y. Watanabe; X. C Zhong

    1997-01-01

    The radiation hardness of prototype CsI(Tl) crystals has been tested for the barrel electromagnetic calorimeter for the BELLE detector of the KEK B factory. Although samples made by one of the producers were found to be soft under irradiation, the problem was quickly improved when this information was fed back. All the tested crystals were found to meet our requirement.The

  8. Transition Radiation Detector in the D0 colliding beam experiment at Fermilab

    SciTech Connect

    Piekarz, H.

    1995-04-01

    The construction, operation and response of the Transition Radiation Detector (TRD) at DO colliding beam experiment at Fermilab are presented. The use of the TRD signal to enhance electron identification and hadronic rejection in the multiparticle background characteristic for the antiproton-proton interactions at the center-of-mass energy of 1.8 TeV is also described and results are discussed.

  9. Reconstruction of charged particle fluxes detected by the Radiation Assessment Detector onboard of MSL

    NASA Astrophysics Data System (ADS)

    Guo, J.; Wimmer-Schweingruber, R. F.; Hassler, D.; Zeitlin, C. J.; Ehresmann, B.; Kohler, J.; Boehm, E.; Appel, J. K.; Lohf, H.; Boettcher, S.; Burmeister, S.; Rafkin, S. C.; Kharytonov, A.; Martin-Garcia, C.; Matthiae, D.; Reitz, G.

    2013-12-01

    One of the main science objectives of the Mars Science Laboratory (MSL) is to help planning future human exploration to Mars by constraining the radiation environment during the cruise phase and on the planet's surface. During the 253-day, 560 million km cruise to Mars, the Radiation Assessment Detector, RAD made detailed measurements of the energy spectrum deposited by energetic particles from space and scattered within the spacecraft. Two types of radiation pose potential health risks to astronauts in deep space: a prolonged low-dose exposure to Galactic Cosmic Rays (GCRs) and short-term exposures to the Solar Energetic Particles (SEPs). On the surface of Mars such energetic particles penetrate through its thin atmosphere and generate secondary particles that can also result harms to humans. In order to interpret the energetic charged particle flux coming into the detector, we have developed the Detector Response Function (DRF) using GEANT 4 simulations and employed a Maximum likelihood inversion technique to invert the detected energy spectrum. This method has been applied to RAD detection of GCRs and secondary charged particles on the Martian surface, giving us an unique insight into their energy fluxes. The spectra of the stopping particle fluxes (hydrogen and helium) are also directly obtained from RAD observations and compared with the inversion results.

  10. High-energy proton radiation damage of high-purity germanium detectors

    NASA Technical Reports Server (NTRS)

    Pehl, R. H.; Varnell, L. S.; Metzger, A. E.

    1978-01-01

    Quantitative studies of radiation damage in high-purity germanium gamma-ray detectors due to high-energy charged particles have been carried out; two 1.0 cm thick planar detectors were irradiated by 6 GeV/c protons. Under proton bombardment, degradation in the energy resolution was found to begin below 7 x 10 to the 7th protons/sq cm and increased proportionately in both detectors until the experiment was terminated at a total flux of 5.7 x 10 to the 8th protons/sq cm, equivalent to about a six year exposure to cosmic-ray protons in space. At the end of the irradiation, the FWHM resolution measured at 1332 keV stood at 8.5 and 13.6 keV, with both detectors of only marginal utility as a spectrometer due to the severe tailing caused by charge trapping. Annealing these detectors after proton damage was found to be much easier than after neutron damage.

  11. Radiation Hardness of Silicon Detectors Manufactured on Epitaxial Material and FZ Bulk Enriched with Oxygen, Carbon, Tin and Platinum

    NASA Astrophysics Data System (ADS)

    Ruzin, A.; Casse, G.; Glaser, M.; Lemeilleur, F.; Talamonti, R.; Watts, S.; Zanet, A.; ROSE Collaboration-RD48

    1999-08-01

    Recent results on the radiation hardness of silicon detectors fabricated on epitaxial and float zone bulk silicon enriched by various impurities, such as carbon, oxygen, tin and platinum are reported. A new methodology of measurements of electrical properties of the devices has been utilized in the experiment. It has been shown that in the case of irradiation by protons, oxygen enriched silicon has better radiation hardness than standard float zone silicon. The carbon enriched silicon detectors, on the other hand, exhibited significantly inferior radiation hardness compared to standard detectors. This study shows for the first time, a violation of the widely used narmalization technique of the various particle irradiations by NIEL coefficients. The study has been carried out in the framework of the RD48 (ROSE) collaboration, which studies the radiation hardening of silicon detectors.

  12. Measurements of mechanical dissipation in high sound velocity materials: implications for resonant-mass gravitational radiation detectors

    Microsoft Academic Search

    En-Ke Hu; C. Zhou; L. Mann; P. F. Michelson; J. C. Price

    1991-01-01

    The sensitivity of resonant-mass gravitational radiation detectors depends on both the antenna cross-section and the detector noise. The cross-section is determined by the sound velocity vs and density varrho of the antenna material, while the principal detector noise sources are thermal Nyquist noise and noise due to the readout electromechanical amplifier. The thermal noise is proportional to T\\/Q, where T

  13. Collisional, radiative and total electron interaction in compound semiconductor detectors and solid state nuclear track detectors: Effective atomic number and electron density.

    PubMed

    Kurudirek, Murat; Kurudirek, Sinem V

    2015-05-01

    Effective atomic numbers, Zeff and electron densities, Ne are widely used for characterization of interaction processes in radiation related studies. A variety of detectors are employed to detect different types of radiations i.e. photons and charged particles. In the present work, some compound semiconductor detectors (CSCD) and solid state nuclear track detectors (SSNTD) were investigated with respect to the partial as well as total electron interactions. Zeff and Ne of the given detectors were calculated for collisional, radiative and total electron interactions in the kinetic energy region 10keV-1GeV. Maximum values of Zeff and Ne were observed at higher kinetic energies of electrons. Significant variations in Zeff and Ne up to ?20-25% were noticed for the detectors, GaN, ZnO, Amber and CR-39 for total electron interaction. Moreover, the obtained Zeff and Ne for electrons were compared to those obtained for photons in the entire energy region. Significant variations in Zeff were also noted not only for photons (up to ?40% for GaN) but also between photons and electrons (up to ?60% for CR-39) especially at lower energies. Except for the lower energies, Zeff and Ne keep more or less constant values for the given materials. The energy regions where Zeff and Ne keep constant clearly show the availability of using these parameters for characterization of the materials with respect to the radiation interaction processes. PMID:25702888

  14. Single charge carrier type sensing with a parallel strip pseudo-Frisch-grid CdZnTe semiconductor radiation detector

    Microsoft Academic Search

    D. S. McGregor; H. A. Seifert; D. K. Wehe; R. A. Rojeski

    Wide band gap compound semiconducting materials of- fer great promise for use as room temperature operated ra- diation detectors. The most common semiconductor radiation detector design incorporates the use of a semiconducting block of material with metal contacts applied at opposite ends of the block. A voltage is applied across the block, which produces an internal electric field capable of

  15. Development of a fast radiation detector based on barium fluoride scintillation crystal

    SciTech Connect

    Han, Hetong [Northwest Institute of Nuclear Technology, NINT, Xi'an 710024, Shaanxi (China) [Northwest Institute of Nuclear Technology, NINT, Xi'an 710024, Shaanxi (China); School of Nuclear Science and Technology, Xi'an Jiaotong University, XJTU, Xi'an 710049, Shaanxi (China); Zhang, Zichuan; Weng, Xiufeng; Liu, Junhong; Zhang, Kan; Li, Gang [Northwest Institute of Nuclear Technology, NINT, Xi'an 710024, Shaanxi (China)] [Northwest Institute of Nuclear Technology, NINT, Xi'an 710024, Shaanxi (China); Guan, Xingyin [School of Nuclear Science and Technology, Xi'an Jiaotong University, XJTU, Xi'an 710049, Shaanxi (China)] [School of Nuclear Science and Technology, Xi'an Jiaotong University, XJTU, Xi'an 710049, Shaanxi (China)

    2013-07-15

    Barium fluoride (BaF{sub 2}) is an inorganic scintillation material used for the detection of X/gamma radiation due to its relatively high density, equivalent atomic number, radiation hardness, and high luminescence. BaF{sub 2} has a potential capacity to be used in gamma ray timing experiments due to the prompt decay emission components. It is known that the light output from BaF{sub 2} has three decay components: two prompt of those at approximately 195 nm and 220 nm with a decay constant around 600-800 ps and a more intense, slow component at approximately 310 nm with a decay constant around 630 ns which hinders fast timing experiments. We report here the development of a fast radiation detector based on a BaF{sub 2} scintillation crystal employing a special optical filter device, a multiple reflection multi-path ultraviolet region short-wavelength pass light guides (MRMP-short pass filter) by using selective reflection technique, for which the intensity of the slow component is reduced to less than 1%. The methods used for this study provide a novel way to design radiation detector by utilizing scintillation crystal with several emission bands.

  16. Development of 2D imaging of SXR plasma radiation by means of GEM detectors

    NASA Astrophysics Data System (ADS)

    Chernyshova, M.; Czarski, T.; Jab?o?ski, S.; Kowalska-Strzeciwilk, E.; Po?niak, K.; Kasprowicz, G.; Zabo?otny, W.; Woje?ski, A.; Byszuk, A.; Burza, M.; Juszczyk, B.; Zienkiewicz, P.

    2014-11-01

    Presented 2D gaseous detector system has been developed and designed to provide energy resolved fast dynamic plasma radiation imaging in the soft X-Ray region with 0.1 kHz exposure frequency for online, made in real time, data acquisition (DAQ) mode. The detection structure is based on triple Gas Electron Multiplier (GEM) amplification structure followed by the pixel readout electrode. The efficiency of detecting unit was adjusted for the radiation energy region of tungsten in high-temperature plasma, the main candidate for the plasma facing material for future thermonuclear reactors. Here we present preliminary laboratory results and detector parameters obtained for the developed system. The operational characteristics and conditions of the detector were designed to work in the X-Ray range of 2-17 keV. The detector linearity was checked using the fluorescence lines of different elements and was found to be sufficient for good photon energy reconstruction. Images of two sources through various screens were performed with an X-Ray laboratory source and 55Fe source showing a good imaging capability. Finally offline stream-handling data acquisition mode has been developed for the detecting system with timing down to the ADC sampling frequency rate (~13 ns), up to 2.5 MHz of exposure frequency, which could pave the way to invaluable physics information about plasma dynamics due to very good time resolving ability. Here we present results of studied spatial resolution and imaging properties of the detector for conditions of laboratory moderate counting rates and high gain.

  17. The effects of proton-induced radiation damage on compound-semiconductor X-ray detectors

    NASA Astrophysics Data System (ADS)

    Owens, Alan; Alha, Lauri; Andersson, Hans; Bavdaz, Marcos; Brammertz, Guy; Helariutta, Kerttuli; Peacock, Anthony; Lämsä, V.; Nenonen, Seppo A. A.

    2004-09-01

    We report the results of a series of experiments designed to assess the relative radiation hardness of a range of compound semiconductor X-ray detectors. The specific compounds tested were GaAs, InP, CdZnTe, HgI2 and TlBr, along with an elemental Si device. To allow meaningful comparisons, all devices were of a similar size and, with the exception of the InP detector, had sub-keV energy resolution at 5.9 keV. The irradiations were carried out using the University of Helsinki"s Cyclone 10/5 10 MeV proton cyclotron. Each detector was given six consecutive exposures - the integral fluences being; 2.66 x 109 p cm-2, 7.98 x 109 p cm-2, 2.65 x 1010 p cm-2, 7.97 x 1010 p cm-2, 1.59 x 1011 p cm-2, and 2.65 x 1011 p cm-2, respectively. In Si, these correspond to absorbed radiation doses of 2, 6, 20, 60, 120 and 200 krads. During the exposures, the detectors were kept unbiased and at room temperature. After each irradiation, the effects of the exposure were assessed, both at room temperature and at a reduced temperature using 55Fe, 109Cd and 241Am radioactive sources. It was found that with the exception of the HgI2 and TlBr detectors all materials showed varying degrees of damage effects.

  18. Radiation Hard Hybrid Pixel Detectors, and a bb¯ Cross-Section Measurement at the CMS Experiment

    NASA Astrophysics Data System (ADS)

    Sibille, Jennifer A.

    Measurements of heavy flavor quark production at hadron colliders provide a good test of the perturbative quantum chromodynamics (pQCD) theory. It is also essential to have a good understanding of the heavy quark production in the search for new physics. Heavy quarks contribute to backgrounds and signals in measurements of higher mass objects, such as the Higgs boson. A key component to each of these measurements is good vertex resolution. In order to ensure reliable operation of the pixel detector, as well as confidence in the results of analyses utilizing it, it is important to study the effects of the radiation on the detector. In the first part of this dissertation, the design of the CMS silicon pixel detector is described. Emphasis is placed on the effects of the high radiation environment on the detector operation. Measurements of the charge collection efficiency, interpixel capacitance, and other properties of the pixel sensors as a function of the radiation damage are presented. In the second part, a measurement of the inclusive bb¯ production cross section using the b ? muD 0X, D0 ? Kpi decay chain with data from the CMS experiment at the LHC is presented. The data were recorded with the CMS experiment at the Large Hadron Collider (CERN) in 2010 using unprescaled single muon triggers corresponding to a total luminosity of 25 pb-1. The differential cross section is measured for pD0mT > 6 GeV/c and |eta| < 2.4 corresponding to a total cross section of 4.36+/-0.54(stat.) +0.28-0.25 (sys.)+/-0.17( B )+/-0.23( L ) mu b.

  19. Scattered radiation in flat-detector based cone-beam CT: analysis of voxelized patient simulations

    NASA Astrophysics Data System (ADS)

    Wiegert, Jens; Bertram, Matthias

    2006-03-01

    This paper presents a systematic assessment of scattered radiation in flat-detector based cone-beam CT. The analysis is based on simulated scatter projections of voxelized CT images of different body regions allowing to accurately quantify scattered radiation of realistic and clinically relevant patient geometries. Using analytically computed primary projection data of high spatial resolution in combination with Monte-Carlo simulated scattered radiation, practically noise-free reference data sets are computed with and without inclusion of scatter. The impact of scatter is studied both in the projection data and in the reconstructed volume for the head, thorax, and pelvis regions. Currently available anti-scatter grid geometries do not sufficiently compensate scatter induced cupping and streak artifacts, requiring additional software-based scatter correction. The required accuracy of scatter compensation approaches increases with increasing patient size.

  20. The iQID camera: An ionizing-radiation quantum imaging detector

    NASA Astrophysics Data System (ADS)

    Miller, Brian W.; Gregory, Stephanie J.; Fuller, Erin S.; Barrett, Harrison H.; Bradford Barber, H.; Furenlid, Lars R.

    2014-12-01

    We have developed and tested a novel, ionizing-radiation Quantum Imaging Detector (iQID). This scintillation-based detector was originally developed as a high-resolution gamma-ray imager, called BazookaSPECT, for use in single-photon emission computed tomography (SPECT). Recently, we have investigated the detector's response and imaging potential with other forms of ionizing radiation including alpha, neutron, beta, and fission fragment particles. The confirmed response to this broad range of ionizing radiation has prompted its new title. The principle operation of the iQID camera involves coupling a scintillator to an image intensifier. The scintillation light generated by particle interactions is optically amplified by the intensifier and then re-imaged onto a CCD/CMOS camera sensor. The intensifier provides sufficient optical gain that practically any CCD/CMOS camera can be used to image ionizing radiation. The spatial location and energy of individual particles are estimated on an event-by-event basis in real time using image analysis algorithms on high-performance graphics processing hardware. Distinguishing features of the iQID camera include portability, large active areas, excellent detection efficiency for charged particles, and high spatial resolution (tens of microns). Although modest, iQID has energy resolution that is sufficient to discriminate between particles. Additionally, spatial features of individual events can be used for particle discrimination. An important iQID imaging application that has recently been developed is real-time, single-particle digital autoradiography. We present the latest results and discuss potential applications.

  1. Light scattering apparatus and method for determining radiation exposure to plastic detectors

    DOEpatents

    Hermes, Robert E. (White Rock, NM)

    2002-01-01

    An improved system and method of analyzing cumulative radiation exposure registered as pits on track etch foils of radiation dosimeters. The light scattering apparatus and method of the present invention increases the speed of analysis while it also provides the ability to analyze exposure levels beyond that which may be properly measured with conventional techniques. Dosimeters often contain small plastic sheets that register accumulated damage when exposed to a radiation source. When the plastic sheet from the dosimeter is chemically etched, a track etch foil is produced wherein pits or holes are created in the plastic. The number of these pits, or holes, per unit of area (pit density) correspond to the amount of cumulative radiation exposure which is being optically measured by the apparatus. To measure the cumulative radiation exposure of a track etch foil a high intensity collimated beam is passed through foil such that the pits and holes within the track etch foil cause a portion of the impinging light beam to become scattered upon exit. The scattered light is focused with a lens, while the primary collimated light beam (unscattered light) is blocked. The scattered light is focused by the lens onto an optical detector capable of registering the optical power of the scattered light which corresponds to the cumulative radiation to which the track etch foil has been exposed.

  2. Signal and noise analysis of a-Si:H radiation detector-amplifier system

    SciTech Connect

    Cho, Gyuseong

    1992-03-01

    Hydrogenated amorphous silicon (a-Si:H) has potential advantages in making radiation detectors for many applications because of its deposition capability on a large-area substrate and its high radiation resistance. Position-sensitive radiation detectors can be made out of a 1d strip or a 2-d pixel array of a Si:H pin diodes. In addition, signal processing electronics can be made by thin-film transistors on the same substrate. The calculated radiation signal, based on a simple charge collection model agreed well with results from various wave length light sources and 1 MeV beta particles on sample diodes. The total noise of the detection system was analyzed into (a) shot noise and (b) 1/f noise from a detector diode, and (c) thermal noise and (d) 1/f noise from the frontend TFT of a charge-sensitive preamplifier. the effective noise charge calculated by convoluting these noise power spectra with the transfer function of a CR-RC shaping amplifier showed a good agreement with the direct measurements of noise charge. The derived equations of signal and noise charge can be used to design an a-Si:H pixel detector amplifier system optimally. Signals from a pixel can be readout using switching TFTs, or diodes. Prototype tests of a double-diode readout scheme showed that the storage time and the readout time are limited by the resistances of the reverse-biased pixel diode and the forward biased switching diodes respectively. A prototype charge-sensitive amplifier was made using poly-Si TFTs to test the feasibility of making pixel-level amplifiers which would be required in small-signal detection. The measured overall gain-bandwidth product was {approximately}400 MHz and the noise charge {approximately}1000 electrons at a 1 {mu}sec shaping time. When the amplifier is connected to a pixel detector of capacitance 0.2 pF, it would give a charge-to-voltage gain of {approximately}0.02 mV/electron with a pulse rise time less than 100 nsec and a dynamic range of 48 dB.

  3. New BNL 3D-Trench Electrode Si Detectors for Radiation Hard Detectors for sLHC and for X-ray Applications

    SciTech Connect

    Li Z.

    2011-05-11

    A new international-patent-pending (PCT/US2010/52887) detector type, named here as 3D-Trench electrode Si detectors, is proposed in this work. In this new 3D electrode configuration, one or both types of electrodes are etched as trenches deep into the Si (fully penetrating with SOI or supporting wafer, or non-fully penetrating into 50-90% of the thickness), instead of columns as in the conventional ('standard') 3D electrode Si detectors. With trench etched electrodes, the electric field in the new 3D electrode detectors are well defined without low or zero field regions. Except near both surfaces of the detector, the electric field in the concentric type 3D-Trench electrode Si detectors is nearly radial with little or no angular dependence in the circular and hexangular (concentric-type) pixel cell geometries. In the case of parallel plate 3D trench pixels, the field is nearly linear (like the planar 2D electrode detectors), with simple and well-defined boundary conditions. Since each pixel cell in a 3D-Trench electrode detector is isolated from others by highly doped trenches, it is an electrically independent cell. Therefore, an alternative name 'Independent Coaxial Detector Array', or ICDA, is assigned to an array of 3D-Trench electrode detectors. The electric field in the detector can be reduced by a factor of nearly 10 with an optimal 3D-Trench configuration where the junction is on the surrounding trench side. The full depletion voltage in this optimal configuration can be up to 7 times less than that of a conventional 3D detector, and even a factor of two less than that of a 2D planar detector with a thickness the same as the electrode spacing in the 3D-Trench electrode detector. In the case of non-fully penetrating trench electrodes, the processing is true one-sided with backside being unprocessed. The charge loss due to the dead space associated with the trenches is insignificant as compared to that due to radiation-induced trapping in sLHC environment. Since the large electrode spacing (up to 500 {micro}m) can be realized in the 3D-Trench electrode detector due to their advantage of greatly reduced full depletion voltage, detectors with large pixel cells (therefore small dead volume) can be made for applications in photon science (e.g. X-ray).

  4. New BNL 3D-Trench electrode Si detectors for radiation hard detectors for sLHC and for X-ray applications

    NASA Astrophysics Data System (ADS)

    Li, Zheng

    2011-12-01

    A new international-patent-pending (PCT/US2010/52887) detector type, named here as 3D-Trench electrode Si detectors, is proposed in this work. In this new 3D electrode configuration, one or both types of electrodes are etched as trenches deep into the Si (fully penetrating with SOI or supporting wafer, or non-fully penetrating into 50-90% of the thickness), instead of columns as in the conventional ("standard") 3D electrode Si detectors. With trench etched electrodes, the electric field in the new 3D electrode detectors are well defined without low or zero field regions. Except near both surfaces of the detector, the electric field in the concentric type 3D-Trench electrode Si detectors is nearly radial with little or no angular dependence in the circular and hexangular (concentric-type) pixel cell geometries. In the case of parallel plate 3D trench pixels, the field is nearly linear (like the planar 2D electrode detectors), with simple and well-defined boundary conditions. Since each pixel cell in a 3D-Trench electrode detector is isolated from others by highly doped trenches, it is an electrically independent cell. Therefore, an alternative name "Independent Coaxial Detector Array", or ICDA, is assigned to an array of 3D-Trench electrode detectors. The electric field in the detector can be reduced by a factor of nearly 10 with an optimal 3D-Trench configuration where the junction is on the surrounding trench side. The full depletion voltage in this optimal configuration can be up to 7 times less than that of a conventional 3D detector, and even a factor of two less than that of a 2D planar detector with a thickness the same as the electrode spacing in the 3D-Trench electrode detector. In the case of non-fully penetrating trench electrodes, the processing is true one-sided with backside being unprocessed. The charge loss due to the dead space associated with the trenches is insignificant as compared to that due to radiation-induced trapping in sLHC environment. Since the large electrode spacing (up to 500 ?m) can be realized in the 3D-Trench electrode detector due to their advantage of greatly reduced full depletion voltage, detectors with large pixel cells (therefore small dead volume) can be made for applications in photon science (e.g. X-ray).

  5. Particle Detectors

    NASA Astrophysics Data System (ADS)

    Grupen, Claus; Shwartz, Boris

    2008-03-01

    Preface to the first edition; Preface to the second edition; Introduction; 1. Interactions of particles and radiation with matter; 2. Characteristic properties of detectors; 3. Units of radiation measurements and radiation sources; 4. Accelerators; 5. Main physical phenomena used for particle detection and basic counter types; 6. Historical track detectors; 7. Track detectors; 8. Calorimetry; 9. Particle identification; 10. Neutrino detectors; 11. Momentum measurement and muon detection; 12. Ageing and radiation effects; 13. Example of a general-purpose detector: Belle; 14. Electronics; 15. Data analysis; 16. Applications of particle detectors outside particle physics; 17. Glossary; 18. Solutions; 19. Resumé; Appendixes; Index.

  6. Particle Detectors

    NASA Astrophysics Data System (ADS)

    Grupen, Claus; Shwartz, Boris

    2011-09-01

    Preface to the first edition; Preface to the second edition; Introduction; 1. Interactions of particles and radiation with matter; 2. Characteristic properties of detectors; 3. Units of radiation measurements and radiation sources; 4. Accelerators; 5. Main physical phenomena used for particle detection and basic counter types; 6. Historical track detectors; 7. Track detectors; 8. Calorimetry; 9. Particle identification; 10. Neutrino detectors; 11. Momentum measurement and muon detection; 12. Ageing and radiation effects; 13. Example of a general-purpose detector: Belle; 14. Electronics; 15. Data analysis; 16. Applications of particle detectors outside particle physics; 17. Glossary; 18. Solutions; 19. Resumé; Appendixes; Index.

  7. Mon. Not. R. Astron. Soc. 391, 617623 (2008) doi:10.1111/j.1365-2966.2008.13941.x Smart detectors for Monte Carlo radiative transfer

    E-print Network

    Baes, Maarten

    that is inherent in Monte Carlo radiative transfer simulations. As the typical detectors used in Monte Carlo negligible, we recommend the use of smart detectors in Monte Carlo radiative transfer simulations. Key wordsMon. Not. R. Astron. Soc. 391, 617­623 (2008) doi:10.1111/j.1365-2966.2008.13941.x Smart detectors

  8. Comparison of Martian Surface Radiation Predictions to the Measurements of Mars Science Laboratory Radiation Assessment Detector (MSL/RAD)

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Cucinotta, Francis A.; Zeitlin, Cary; Hassler, Donald M.; Ehresmann, Bent; Rafkin, Scot C. R.; Wimmer-Schweingruber, Robert F; Boettcher, Stephan; Boehm, Eckart; Guo, Jingnan; Koehler, Jan; Martin, Cesar; Reitz, Guenther; Posner, Erik

    2014-01-01

    For the analysis of radiation risks to astronauts and planning exploratory space missions, detailed knowledge of particle spectra is an important factor. Detailed measurements of the energetic particle radiation environment on the surface of Mars have been made by the Mars Science Laboratory Radiation Assessment Detector (MSL-RAD) on the Curiosity rover since August 2012, and particle fluxes for a wide range of ion species (up to several hundred MeV/u) and high energy neutrons (8 - 1000 MeV) have been available for the first 200 sols. Although the data obtained on the surface of Mars for 200 sols are limited in the narrow energy spectra, the simulation results using the Badhwar-O'Neill galactic cosmic ray (GCR) environment model and the high-charge and energy transport (HZETRN) code are compared to the data. For the nuclear interactions of primary GCR through Mars atmosphere and Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation (QMSFRG) is used, which includes direct knockout, evaporation and nuclear coalescence. Daily atmospheric pressure measurements at Gale Crater by the MSL Rover Environmental Monitoring Station are implemented into transport calculations for describing the daily column depth of atmosphere. Particles impinging on top of the Martian atmosphere reach the RAD after traversing varying depths of atmosphere that depend on the slant angles, and the model accounts for shielding of the RAD by the rest of the instrument. Calculations of stopping particle spectra are in good agreement with the RAD measurements for the first 200 sols by accounting changing heliospheric conditions and atmospheric pressure. Detailed comparisons between model predictions and spectral data of various particle types provide the validation of radiation transport models, and thus increase the accuracy of the predictions of future radiation environments on Mars. These contributions lend support to the understanding of radiation health risks to astronauts for the planning of various mission scenarios.

  9. Next Generation Semiconductor-Based Radiation Detectors Using Cadmium Magnesium Telluride

    SciTech Connect

    Trivedi, Sudhir B [Brimrose Technology Corporation; Kutcher, Susan W [Brimrose Technology Corporation; Berding, Martha . [SRI International; Burger, Arnold . [Independent Consultant; Palosz, Witold . [Brimrose Technology Corporation

    2014-11-17

    The primary objective of Phase I was to perform extensive studies on the purification, crystal growth and annealing procedures of CdMgTe to gain a clear understanding of the basic material properties to enable production of detector material with performance comparable to that of CdZnTe. Brimrose utilized prior experience in the growth and processing of II-VI crystals and produced high purity material and good quality single crystals of CdMgTe. Processing techniques for these crystals including annealing, mechanical and chemical polishing, surface passivation and electrode fabrication were developed. Techniques to characterize pertinent electronic characteristics were developed and gamma ray detectors were fabricated. Feasibility of the development of comprehensive defect modeling in this new class of material was demonstrated by our partner research institute SRI International, to compliment the experimental work. We successfully produced a CdMgTe detector that showed 662 keV gamma response with energy resolution of 3.4% (FWHM) at room temperature, without any additional signal correction. These results are comparable to existing CdZnTe (CZT) technology using the same detector size and testing conditions. We have successfully demonstrated detection of gamma-radiation from various isotopes/sources, using CdMgTe thus clearly proving the feasibility that CdMgTe is an excellent, low-cost alternative to CdZnTe.

  10. Radiation effects on the silicon semiconductor detectors for the ASTRO-H mission

    NASA Astrophysics Data System (ADS)

    Hayashi, Katsuhiro; Park, InChun; Dotsu, Kyohei; Ueno, Issei; Nishino, Sho; Matsuoka, Masayuki; Yasuda, Hajimu; Fukazawa, Yasushi; Ohsugi, Takashi; Mizuno, Tsunefumi; Takahashi, Hiromitsu; Ohno, Masanori; Endo, Satoru; Tanaka, Takaaki; Tajima, Hiroyasu; Kokubun, Motohide; Watanabe, Shin; Takahashi, Tadayuki; Nakazawa, Kazuhiro; Uchihori, Yukio; Kitamura, Hisashi

    2013-01-01

    Hard X-ray Imager (HXI) and Soft Gamma-ray Detector (SGD) onboard the 6th Japanese X-ray satellite, ASTRO-H, utilize double-sided silicon strip detectors (DSSD) and pixel array-type silicon sensors (Si-pad), respectively. The DSSD with a 3.4 cm×3.4 cm area has an imaging capability in the lower energy band for the HXI covering 5-80 keV. The Si-pad consists of 16×16 pixels with a 5.4 cm×5.4 cm area and measures a photon direction with the Compton kinematics in 10-600 keV. Since the ASTRO-H will be operated in a low earth orbit, these detectors will be damaged by irradiation of cosmic-ray protons mainly in the South Atlantic Anomaly. In order to evaluate damage effects of the sensors, we have carried out irradiation tests with 150 MeV proton beams and 60Co gamma-rays with a total dose of 10-20 years irradiation level. In both experiments, the leakage current has increased by ˜0.2--1.1 nA/cm2 under an expected operation temperature at -15 °C, which resulted in the noise level within a tolerance of 20 years. In this report, we present a summary of the basic performance of silicon detectors, and radiation effects on them by the irradiation tests.

  11. Design, fabrication and performance optimization of bi-polar blocking planar HPGe radiation detector

    NASA Astrophysics Data System (ADS)

    Khizar, Muhammad; Wang, Guojian; Mei, Dongming

    2013-03-01

    A prototype planar radiation detector is designed, fabricated and characterized using bi-polar contact deposited on high purity single crystal germanium (HPGe). Performances of planar and semi-planar detectors are carried out for their low background counting and high absolute efficiency for high-energy photons applications. For this study, 40mm ? 15mm (diameter to vertical height) p-type HPGe samples with dislocation density EPD 3000 cm-2 are taken from HPGe ingots grown by Czochralski method. After a successful mechanical preparation, and standard cleaning and polishing procedure, samples are chemically etched by using a mixture of highly concentrated acids HF:HNO3 (1:4) in order to remove the surface oxides. A bi-polar blocking layer of amorphous germanium (a-Ge) is deposited on both the samples using low temperature RF sputtering plasma in a pre-mix precursor of H2 (15%) and Ar. For this, an optimized dose of the plasma power and chamber pressure is used for a controlled low temperature. The process was completed with the evaporation of Ohmic contacts using electron beam evaporator. This is worth noticing that special care is introduced during the handling of these samples, especially for the bi-polar blocking and metal contact layers deposition. Finally, the fabricated detectors are characterized at 77K temperature. In this paper, we show the results from the first prototype detector made of home grown crystals at USD.

  12. Detector control system for the ATLAS Transition Radiation Tracker: architecture and development techniques

    NASA Astrophysics Data System (ADS)

    Bana?, El?bieta; Hajduk, Zbigniew; Olszowska, Jolanta

    2012-05-01

    The ATLAS Transition Radiation Tracker (TRT) is the outermost of the three sub-systems of the ATLAS Inner Detector at the Large Hadron Collider at CERN. With ~300000 drift tube proportional counters (straws) filled with stable gas mixture and high voltage biased it provides precise quasi-continuous tracking and particles identification. Safe, coherent and efficient operation of the TRT is fulfilled with the help of the Detector Control System (DCS) running on 11 computers as PVSS (industrial SCADA) projects. Standard industrial and custom developed server applications and protocols are used for reading hardware parameters. Higher level control system layers based on the CERN JCOP framework allow for automatic control procedures, efficient error recognition and handling and provide a synchronization mechanism with the ATLAS data acquisition system. Different data bases are used to store the detector online parameters, the configuration parameters and replicate a subset of them used to flag data quality for physics reconstruction. The TRT DCS is fully integrated with the ATLAS Detector Control System.

  13. Traceable calibration of a fibre-coupled superconducting nano-wire single photon detector using characterized synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Müller, Ingmar; Klein, Roman M.; Werner, Lutz

    2014-12-01

    Radiometric calibrations of fibre-coupled single photon detectors are experiencing growing demand, especially at the telecommunication wavelengths. In this paper, the radiometric calibration of a fibre-coupled superconducting nano-wire single photon detector at the telecom wavelength 1.55 µm by means of well-characterized synchrotron radiation is described. This substitution method is based on the unique properties of synchrotron radiation and the Metrology Light Source, the dedicated electron storage ring of the Physikalisch-Technische Bundesanstalt, and is suitable for fibre-coupled single photon detectors. The Metrology Light Source is used as a light source with a high dynamic range of the radiant power to bridge the radiometric gap occurring in the transition from radiant power measurements and the counting of photons with single photon detectors. Very low uncertainties below 2% have been achieved in the measurement of the detection efficiency of a fibre-coupled superconducting nano-wire single photon detector.

  14. Bidimensional polycrystalline CVD diamond detector for Intensity Modulated Radiation Therapy pre-treatment verifications

    NASA Astrophysics Data System (ADS)

    Zani, M.; Scaringella, M.; Talamonti, C.; De Sio, A.; Pace, E.; Tozzetti, L.; Baldi, A.; Bucciolini, M.; Bruzzi, M.

    2015-03-01

    This study aims at investigating the possible employment for pre-treatment verifications in Intensity Modulated Radiation Therapy (IMRT) of a polycrystalline Chemical Vapour Deposited (pCVD) diamond bidimensional detector. The pCVD device, with an area of 2.5 × 2.5 cm2 (12 × 12 pixels), has been used to measure dose maps of a 10 MVRX prostatic IMRT field. Its response was compared both with a commercial bi-dimensional detector made with silicon and with Treatment Planning System (TPS) calculations.Measurement provided promising results on a map of 1.8 × 12.6 cm2. Absorbed doses measured along IMRT profiles by our device are consistent with the ones acquired with the commercial device and an overall good agreement with respect to the TPS was found for the diamond dosimeter.

  15. Radiation Pressure Induced Instabilities in Laser Interferometric Detectors of Gravitational Waves

    E-print Network

    A. Pai; S. V. Dhurandhar; P. Hello; J-Y. Vinet

    2000-11-28

    The large scale interferometric gravitational wave detectors consist of Fabry-Perot cavities operating at very high powers ranging from tens of kW to MW for next generations. The high powers may result in several nonlinear effects which would affect the performance of the detector. In this paper, we investigate the effects of radiation pressure, which tend to displace the mirrors from their resonant position resulting in the detuning of the cavity. We observe a remarkable effect, namely, that the freely hanging mirrors gain energy continuously and swing with increasing amplitude. It is found that the `time delay', that is, the time taken for the field to adjust to its instantaneous equilibrium value, when the mirrors are in motion, is responsible for this effect. This effect is likely to be important in the optimal operation of the full-scale interferometers such as VIRGO and LIGO.

  16. Measurement of a high electrical quality factor in a niobium resonator for a gravitational radiation detector

    NASA Technical Reports Server (NTRS)

    Folkner, W. M.; Moody, M. V.; Richard, J.-P.

    1989-01-01

    The mechanical and electrical quality factors of a 10-g niobium resonator were measured at 4.4 K and were found to be 8.1 x 10 to the 6th, and 3.8 x 10 to the 6th, respectively. The value for the electrical quality factor is high enough for a system operating at 50 mK at a sensitivity level of one phonon. The resonator's low damping properties make it suitable for use as a transducer for a cryogenic three-mode gravitational radiation detector. A practical design is given for the mounting of the resonator on a 2400-kg aluminum-bar detector. Projections are made for the sensitivity of a 2400-kg bar instrumented as a three-mode system with this resonator inductively coupled to a SQUID.

  17. Response of a hybrid pixel detector (MEDIPIX3) to different radiation sources for medical applications

    NASA Astrophysics Data System (ADS)

    Chumacero, E. Miguel; De Celis Alonso, B.; Martínez Hernández, M. I.; Vargas, G.; Moreno Barbosa, F.; Moreno Barbosa, E.

    2014-11-01

    The development in semiconductor CMOS technology has enabled the creation of sensitive detectors for a wide range of ionizing radiation. These devices are suitable for photon counting and can be used in imaging and tomography X-ray diagnostics. The Medipix[1] radiation detection system is a hybrid silicon pixel chip developed for particle tracking applications in High Energy Physics. Its exceptional features (high spatial and energy resolution, embedded ultra fast readout, different operation modes, etc.) make the Medipix an attractive device for applications in medical imaging. In this work the energy characterization of a third-generation Medipix chip (Medipix3) coupled to a silicon sensor is presented. We used different radiation sources (strontium 90, iron 55 and americium 241) to obtain the response curve of the hybrid detector as a function of energy. We also studied the contrast of the Medipix as a measure of pixel noise. Finally we studied the response to fluorescence X rays from different target materials (In, Pd and Cd) for the two data acquisition modes of the chip; single pixel mode and charge summing mode.

  18. Radiation-hard active CMOS pixel sensors for HL-LHC detector upgrades

    NASA Astrophysics Data System (ADS)

    Backhaus, Malte

    2015-02-01

    The luminosity of the Large Hadron Collider (LHC) will be increased during the Long Shutdown of 2022 and 2023 (LS3) in order to increase the sensitivity of its experiments. A completely new inner detector for the ATLAS experiment needs to be developed to withstand the extremely harsh environment of the upgraded, so-called High-Luminosity LHC (HL-LHC). High radiation hardness as well as granularity is mandatory to cope with the requirements in terms of radiation damage as well as particle occupancy. A new silicon detector concept that uses commercial high voltage and/or high resistivity full complementary metal-oxide-semiconductor (CMOS) processes as active sensor for pixel and/or strip layers has risen high attention, because it potentially provides high radiation hardness and granularity and at the same time reduced price due to the commercial processing and possibly relaxed requirements for the hybridization technique. Results on the first prototypes characterized in a variety of laboratory as well as test beam environments are presented.

  19. A Compact Combinatorial Device for Measurement of Nonlinearity of Radiation Detectors

    NASA Astrophysics Data System (ADS)

    Saunders, P.; White, D. R.; Edgar, H.

    2015-03-01

    A new compact computer-controlled device using a combinatorial technique for measuring the nonlinearity of radiation detectors is described. The device consists of two sets of four beam-splitter cubes optically cemented together and arranged so that radiation from a single source is split into four separate paths, then recombined after passing through one of five neutral density filters placed in each path. This allows for the measurement of 625 approximately equi-spaced inter-related flux levels based on only 16 unknown transmittance values. These can be solved for by least-squares fitting, leaving 609 degrees of freedom remaining to determine the nonlinearity of the detector. A novel aspect of the design is the use of neutral density glass plates optically cemented along all the external faces of the beam-splitter cubes, which act as beam dumps for any reflected or scattered radiation. The cube faces in the desired beam paths have clear glass plates with an anti-reflection coating applied at the wavelength of interest optically cemented to them. Operation at other wavelengths is achieved by simply replacing these plates with plates coated for the new wavelength. The performance of the device has been tested using a silicon photodiode with a collimated 650 nm LED as the source. The results demonstrate that the device is able to measure linearity to better than 1 part in.

  20. A broadband plasma radiation detector with spatial resolution based on the optical scanning of the fluorescence of a phosphor

    Microsoft Academic Search

    B. Zurro

    1991-01-01

    A detector which converts the line-integrated plasma radiation profile to visible light within a selected spectral range, by means of a film of sodium salicylate, is presented. The phosphor fluorescent emission is spatially scanned by a rapidly vibrating mirror and detected by a filtered photomultiplier, allowing one to measure the time evolution of plasma radiation profiles in real time. A

  1. Development of High Energy Particle Detector for the Study of Space Radiation Storm

    NASA Astrophysics Data System (ADS)

    Jo, Gyeong-Bok; Sohn, Jongdae; Choi, Cheong Rim; Yi, Yu; Min, Kyoung-Wook; Kang, Suk-Bin; Na, Go Woon; Shin, Goo-Hwan

    2014-09-01

    Next Generation Small Satellite-1 (NEXTSat-1) is scheduled to launch in 2017 and Instruments for the Study of Space Storm (ISSS) is planned to be onboard the NEXTSat-1. High Energy Particle Detector (HEPD) is one of the equipment comprising ISSS and the main objective of HEPD is to measure the high energy particles streaming into the Earth radiation belt during the event of a space storm, especially, electrons and protons, to obtain the flux information of those particles. For the design of HEPD, the Geometrical Factor was calculated to be 0.05 to be consistent with the targets of measurement and the structure of telescope with field of view of 33.4°? was designed using this factor. In order to decide the thickness of the detector sensor and the classification of the detection channels, a simulation was performed using GEANT4. Based on the simulation results, two silicon detectors with 1 mm thickness were selected and the aluminum foil of 0.05 mm is placed right in front of the silicon detectors to shield low energy particles. The detection channels are divided into an electron channel and two proton channels based on the measured LET of the particle. If the measured LET is less than 0.8 MeV, the particle belongs to the electron channel, otherwise it belongs to proton channels. HEPD is installed in the direction of 0°?,45°?,90°? against the along-track of a satellite to enable the efficient measurement of high energy particles. HEPD detects electrons with the energy of 0.1 MeV to several MeV and protons with the energy of more than a few MeV. Thus, the study on the dynamic mechanism of these particles in the Earth radiation belt will be performed.

  2. Photodiode radiation hardness, lyman-alpha emitting galaxies and photon detection in liquid argon neutrino detectors

    NASA Astrophysics Data System (ADS)

    Baptista, Brian

    My dissertation is comprised of three projects: 1) studies of Lyman-alpha Emitting galaxies (LAEs), 2) radiation hardness studies of InGaAs photodiodes (PDs), and 3) scintillation photon detection in liquid argon (LAr) neutrino detectors. I began work on the project that has now become WFIRST, developing a science case that would use WFIRST after launch for the observation of LAEs. The radiation hardness of PDs was as an effort to support the WFIRST calibration team. When WFIRST was significantly delayed, I joined an R&D effort that applied my skills to work on photon detection in LAr neutrino detectors. I report results on a broadband selection method developed to detect high equivalent width (EW) LAEs. Using photometry from the CFHT-Legacy Survey Deep 2 and 3 fields, I have spectroscopically confirmed 63 z=2.5-3.5 LAEs using the WIYN/Hydra spectrograph. Using UV continuum-fitting techniques I computed properties such as EWs, internal reddening and star formation rates. 62 of my LAEs show evidence to be normal dust-free LAEs. Second, I present an investigation into the effects of ionizing proton radiation on commercial off-the-shelf InGaAs PDs. I developed a monochromator-based test apparatus that utilized NIST-calibrated reference PDs. I tested the PDs for changes to their dark current, relative responsivity as a function of wavelength, and absolute responsivity. I irradiated the test PDs using 30, 52, and 98 MeV protons at the IU Cyclotron Facility. I found the InGaAs PDs showed increased dark current as the fluence increased with no evidence of broadband response degradation at the fluences expected at an L2 orbit and a 10-year mission lifetime. Finally, I detail my efforts on technology development of both optical detector technologies and waveshifting light guide construction for LAr vacuum UV scintillation light. Cryogenic neutrino detectors use photon detection for both accelerator based science and for SNe neutrino detection and proton decay. I have developed waveshifter doped cast acrylic light guides that convert scintillation light and guide the waveshifted light to SiPMs detectors.

  3. Wide Band-Gap Semiconductor Radiation Detectors: Science Fiction, Horror Story, or Headlines (460th Brookhaven Lecture)

    SciTech Connect

    James, Ralph (BNL Nonproliferation and National Security Department) [BNL Nonproliferation and National Security Department

    2010-08-18

    With radiation constantly occurring from natural sources all around us -- from food, building materials, and rays from the sun, to name a few -- detecting radiotracers for medical procedures and other radiation to keep people safe is not easy. In order to make better use of radiation to diagnose or treat certain health conditions, or to track radiological materials being transported, stored, and used, the quest is on to develop improved radiation detectors. James gives a brief introduction on radiation detection and explain how it is used in applications ranging from medical to homeland security. He then discusses how new materials and better ways to analyze them here at the National Synchrotron Light Source (NSLS) and the future NSLS-II will lead to a new class of radiation detectors that will provide unprecedented advances in medical and industrial imaging, basic science, and the nonproliferation of nuclear materials.

  4. Cryogenic and radiation hard ASIC design for large format NIR/SWIR detector

    NASA Astrophysics Data System (ADS)

    Gao, Peng; Dupont, Benoit; Dierickx, Bart; Müller, Eric; Verbruggen, Geert; Gielis, Stijn; Valvekens, Ramses

    2014-10-01

    An ASIC is developed to control and data quantization for large format NIR/SWIR detector arrays. Both cryogenic and space radiation environment issue are considered during the design. Therefore it can be integrated in the cryogenic chamber, which reduces significantly the vast amount of long wires going in and out the cryogenic chamber, i.e. benefits EMI and noise concerns, as well as the power consumption of cooling system and interfacing circuits. In this paper, we will describe the development of this prototype ASIC for image sensor driving and signal processing as well as the testing in both room and cryogenic temperature.

  5. Post-growth Annealing of Cadmium Zinc Telluride Crystals for Room-Temperature Radiation Detectors

    NASA Astrophysics Data System (ADS)

    Yang, G.; Bolotnikov, A. E.; Fochuk, P. M.; Cui, Y.; Camarda, G. S.; Hossain, A.; Kim, K. H.; Horace, J.; McCall, B.; Gul, R.; Kopach, O. V.; Egarievwe, S. U.; James, R. B.

    2012-10-01

    We investigated the effects of post-growth annealing on cadmium zinc telluride crystals intended for use as room-temperature radiation detectors. Annealing under Cd vapor effectively eliminated Te inclusions. The material's resistivity was lowered, and loss of Zn component was observed. Annealing under Cd + Zn vapors similarly removed Te inclusions. Furthermore, after exposure to the two vapors, we noted a change in the crystal surface morphology, i.e., formation of patterns of parallel lines. In contrast to annealing under Cd vapor alone, high resistivity was maintained after suitably controlling the Cd and Zn pressures.

  6. Evaluating Zn2SiO4:Mn phosphor for use in medical imaging radiation detectors

    Microsoft Academic Search

    I. Kandarakis; D. Cavouras; P. Prassopoulos; E. Kanellopoulos; C. D. Nomicos; G. S. Panayiotakis

    1998-01-01

    2  SiO4:Mn phosphor was evaluated for use in radiation detectors of medical imaging systems. Zn2SiO4:Mn was used in the form of laboratory-prepared fluorescent layers (screens) with coating weights from 18 to 150 mg\\/cm2. The phosphor was excited to luminescence by low-energy X-raysusing X-raytube voltages ranging from 15 to 50 kVp. The number\\u000a of emitted optical photons per incident X-rayquantum was thus determined for

  7. State of the art of wide-bandgap semiconductor nuclear radiation detectors

    Microsoft Academic Search

    M. Schieber; R. B. James; J. C. Lund; D. S. McGregor; T. S. Gilbert; J. M. Van Scyoc; R. W. Olsen; A. E. Pontau; T. S. Schlesinger; J. Toney

    1996-01-01

    Summary  The leading materials which operate as room temperature nuclear radiation detectors are HgI2, CdTe, and Cd1?x\\u000a Zn\\u000a x\\u000a Te (0.05>x>0.25). However, additional materials have also been developed, such as semi-insulating GaAs and PbI2. A comparison of the charge transport properties of all these materials will be made, followed by a discussion of each of\\u000a the materials separately. Crystal growth methods

  8. Method and device for demounting in a radiation detector a photomultiplier tube

    SciTech Connect

    Persyk, D.E.; Stoub, E.W.

    1986-03-11

    A device is described for demounting in a radiation detector a photomultiplier tube which is bonded with its scintillation crystal assembly by means of an elastic light transparent adhesive, comprising: (a) a music wire of about 0.01 to 0.03 inch diameter which forms a noose between its wire ends, the noose being provided for being placed aroung the bond; and (b) twisting means connected with both wire ends for twisting them such that the noose becomes smaller thereby sharing the bond.

  9. Research progress in radiation detectors, pattern recognition programs, and radiation damage determination in DNA

    NASA Technical Reports Server (NTRS)

    Baily, N. A.

    1973-01-01

    The radiological implications of statistical variations in energy deposition by ionizing radiation were investigated in the conduct of the following experiments: (1) study of the production of secondary particles generated by the passage of the primary radiation through bone and muscle; (2) the study of the ratio of nonreparable to reparable damage in DNA as a function of different energy deposition patterns generated by X rays versus heavy fast charged particles; (3) the use of electronic radiography systems for direct fluoroscopic tomography and for the synthesis of multiple planes and; (4) the determination of the characteristics of systems response to split fields having different contrast levels, and of minimum detectable contrast levels between the halves under realistic clinical situations.

  10. Gadolinium-doped water cerenkov-based neutron and high energy gamma-ray detector and radiation portal monitoring system

    DOEpatents

    Dazeley, Steven A; Svoboda, Robert C; Bernstein, Adam; Bowden, Nathaniel

    2013-02-12

    A water Cerenkov-based neutron and high energy gamma ray detector and radiation portal monitoring system using water doped with a Gadolinium (Gd)-based compound as the Cerenkov radiator. An optically opaque enclosure is provided surrounding a detection chamber filled with the Cerenkov radiator, and photomultipliers are optically connected to the detect Cerenkov radiation generated by the Cerenkov radiator from incident high energy gamma rays or gamma rays induced by neutron capture on the Gd of incident neutrons from a fission source. The PMT signals are then used to determine time correlations indicative of neutron multiplicity events characteristic of a fission source.

  11. Transient current analysis of a GaN radiation detector by TCAD

    NASA Astrophysics Data System (ADS)

    Wang, Jinghui; Mulligan, Padhraic L.; Cao, Lei R.

    2014-10-01

    A gallium nitride (GaN) Schottky diode radiation detector has been fabricated with a successfully demonstrated radiation response to alpha particles and neutrons when using Li as a convertor. In order to understand the charge collection process for further device modification, the Sentaurus TCAD software package is employed to quantitatively study the transient current produced by energetic charge particles. By comparing the simulation and experimental results, especially the capacitance-voltage relationship and charge collection efficiency, the device parameters and physics models used for the simulation are validated. The time behavior of the transient current is studied, and the carrier generation/loss by impact ionization, recombination, and trapping are discussed. The total collected charge contributed by various components, such as drift, funneling, and diffusion are also analyzed.

  12. Radiation detector using a bulk high T.sub.c superconductor

    DOEpatents

    Artuso, Joseph F. (Santa Barbara, CA); Franks, Larry A. (Santa Barbara, CA); Hull, Kenneth L. (Ventura, CA); Symko, Orest G. (Salt Lake City, UT)

    1993-01-01

    A radiation detector (10) is provided, wherein a bulk high T.sub.c superconducting sample (11) is placed in a magnetic field and maintained at a superconducting temperature. Photons of incident radiation will cause localized heating in superconducting loops of the sample destroying trapped flux and redistributing the fluxons, and reducing the critical current of the loops. Subsequent cooling of the sample in the magnetic field will cause trapped flux redistributed Abrikosov fluxons and trapped Josephson fluxons. The destruction and trapping of the fluxons causes changes in the magnetization of the sample inducing currents in opposite directions in a pickup coil (12) which is coupled by an input coil (15) to an rf SQUID (16).

  13. Characterization of CdMnTe radiation detectors using current and charge transients

    NASA Astrophysics Data System (ADS)

    Rafiei, R.; Reinhard, M. I.; Sarbutt, A.; Uxa, S.; Boardman, D.; Watt, G. C.; Belas, E.; Kim, K.; Bolotnikov, A. E.; James, R. B.

    2013-07-01

    Charge transport characteristics of Cd0.95Mn0.05Te: In radiation detectors have been evaluated by combining time resolved current transient measurements with time of flight charge transient measurements. The shapes of the measured current pulses have been interpreted with respect to a concentration of net positive space-charge, which has resulted in an electric field gradient across the detector bulk. From the recorded current pulses the charge collection efficiency of the detector was found to approach 100%. From the evolution of the charge collection efficiency with applied bias, the electron mobility-lifetime product of ?n?n = (8.5 ± 0.4) × 10-4 cm2/V has been estimated. The electron transit time was determined using both transient current technique and time of flight measurements in the bias range of 100-1900 V From the dependence of drift velocity on applied electric field the electron mobility was found to be ?n = (718 ± 55) cm2/(V.s) at room temperature.

  14. Material analysis of the CZT crystal grown for a radiation detector

    NASA Astrophysics Data System (ADS)

    Kim, Han Soo; Jeong, Manhee; Kim, Young Soo; Kim, Dong Jin; Choi, Hyo Jeong

    2015-01-01

    Room-temperature semiconductor radiation detectors, such as CdZnTe (CZT) and CdTe detectors, are being developed and grown worldwide owing to their high performances as a gamma-ray detector. A 2? CZT ingot was grown using a 6-zone low-pressure (LP) Bridgman furnace at the Korea Atomic Energy Research Institute (KAERI). To increase the resistivity, indium (In) was doped at 5 ppm and 7 ppm, respectively. Material analysis results obtained by using inductively coupled plasma mass spectrometry (ICP-MS), X-ray diffractometry (XRD), and an infrared (IR) scope system were compared with the I-V results with respect to the location on the grown ingots and doping concentration. A (1,1,1) orientation and 1.41 × 1011 ?·cm resistivity were measured in the middle part of the ingot. In addition, Te inclusions were also homogeneously shown. The variation in the I-V characteristics with respect to the preparation conditions of the crystals was also addressed.

  15. Radiation tolerance of prototype BTeV pixel detector readout chips

    SciTech Connect

    Gabriele Chiodini et al.

    2002-07-12

    High energy and nuclear physics experiments need tracking devices with increasing spatial precision and readout speed in the face of ever-higher track densities and increased radiation environments. The new generation of hybrid pixel detectors (arrays of silicon diodes bump bonded to arrays of front-end electronic cells) is the state of the art technology able to meet these challenges. We report on irradiation studies performed on BTeV pixel readout chip prototypes exposed to a 200 MeV proton beam at Indiana University Cyclotron Facility. Prototype pixel readout chip preFPIX2 has been developed at Fermilab for collider experiments and implemented in standard 0.25 micron CMOS technology following radiation tolerant design rules. The tests confirmed the radiation tolerance of the chip design to proton total dose up to 87 MRad. In addition, non destructive radiation-induced single event upsets have been observed in on-chip static registers and the single bit upset cross section has been extensively measured.

  16. Thermodynamics of post-growth annealing of cadmium zinc telluride nuclear radiation detectors

    NASA Astrophysics Data System (ADS)

    Adams, Aaron Lee

    Nuclear Radiation Detectors are used for detecting, tracking, and identifying radioactive materials which emit high-energy gamma and X-rays. The use of Cadmium Zinc Telluride (CdZnTe) detectors is particularly attractive because of the detector's ability to operate at room temperature and measure the energy spectra of gamma-ray sources with a high resolution, typically less than 1% at 662 keV. While CdZnTe detectors are acceptable imperfections in the crystals limit their full market potential. One of the major imperfections are Tellurium inclusions generated during the crystal growth process by the retrograde solubility of Tellurium and Tellurium-rich melt trapped at the growth interface. Tellurium inclusions trap charge carriers generated by gamma and X-ray photons and thus reduce the portion of generated charge carriers that reach the electrodes for collection and conversion into a readable signal which is representative of the ionizing radiation's energy and intensity. One approach in resolving this problem is post-growth annealing which has the potential of removing the Tellurium inclusions and associated impurities. The goal of this project is to use experimental techniques to study the thermodynamics of Tellurium inclusion migration in post-growth annealing of CdZnTe nuclear detectors with the temperature gradient zone migration (TGZM) technique. Systematic experiments will be carried out to provide adequate thermodynamic data that will inform the engineering community of the optimum annealing parameters. Additionally, multivariable correlations that involve the Tellurium diffusion coefficient, annealing parameters, and CdZnTe properties will be analyzed. The experimental approach will involve systematic annealing experiments (in Cd vapor overpressure) on different sizes of CdZnTe crystals at varying temperature gradients ranging from 0 to 60°C/mm (used to migrate the Tellurium inclusion to one side of the crystal), and at annealing temperatures ranging from 500 to 800°C. The characterization techniques that will be used to quantify the effects of the post-growth annealing experiments include: 1) 3D infrared transmission microscopy to measure the size, distribution, and concentration of Tellurium inclusions; 2) current-voltage measurements to determine the effect of post-growth annealing on the resistivity of CdZnTe crystals; and 3) X-ray diffraction topography, available at the National Synchrotron Light Source (NSLS) facilities at Brookhaven National Laboratory (BNL), to measure the correlation between device performance and annealing conditions

  17. Radiation damage to neutron and proton irradiated GaAs particle detectors

    E-print Network

    M. Rogalla; Th. Eich; N. Evans; S. Joost; M. Kienzle; R. Geppert; R. Goeppert; R. Irsigler; J. Ludwig; K. Runge; Th. Schmid

    1997-04-04

    The radiation damage in 200 um thick Schottky diodes made on semi-insulating (SI) undoped GaAs Liquid Encapsulated Czochralski (LEC) bulk material with resistivities between 0.4 and 8.9*10E7 Ohm*cm were studied using alpha-spectroscopy, signal response to minimum ionising particles (MIP), I-V and CV-measurements. The results have been analysed to investigate the influence of the substrate resistivity on the detector performance after neutron and proton irradiation. The leakage current density, signal response to alpha-particles and MIPs show a strong dependence on the resistivity before and after irradiation. An observed decrease of the electron mean free drift length before and after irradiation with increasing substrate resistivity can be explained by a model involving the different ionisation ratios of defects, which are introduced by the irradiation. Comparison of the radiation damage due to neutrons and protons gives a hardness factor of 7+-0.9 for 24 GeV/c protons. The best detectors show a response to MIPs of 5250 e- at 200 V reverse bias after a irradiation level of 2*10E14 p/cm^2.

  18. Scintillation detectors based on poly-2,4-dimethylstyrene: Structure peculiarities and radiation damage

    SciTech Connect

    Gunder, O.A.; Voronkina, N.I.; Kopina, I.V. [Institute for Single Crystals, Kharkov (Ukraine)] [Institute for Single Crystals, Kharkov (Ukraine)

    1995-08-01

    Scintillation detectors based on poly-2,4-dimethyl styrene (P-2,4-DMS) are studied. Investigated is the influence of two methyl groups present in the benzene ring on the energy, spectral and structural characteristics of the polymer. The said factors are assumed to result in the detectors high light output and radiation resistance. It is shown that under radiolysis (77 K) the radiation yield of the paramagnetic centers of P-2,4-DMS exceeds that of polystyrene (PST) by {approximately} 1.5. Unlike PST film, the luminescence spectra of P-2,4-DMS are characterized by the presence of both excimer (320-340 nm) and monomer (292 nm) bands. Revealed are the distinction in the nature of the optical characteristics of macroradicals and the efficiency of energy transfer in gamma-irradiated PST and P-2,4-DMS scintillators. The relation between the super-molecular structure of the polymers and the interaction of their macroradicals with molecular O{sub 2} is stated.

  19. High purity liquid phase epitaxial GaAs for radiation detectors

    SciTech Connect

    Wynne, D.I.; Haller, E.E. [Lawrence Berkeley National Lab., CA (United States); [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering; Rossington Tull, C.S. [Lawrence Berkeley National Lab., CA (United States)

    1998-12-31

    The authors report on the growth of high purity n-GaAs using Liquid Phase Epitaxy (LPE) and the fabrication of room temperature p-i-n radiation detectors. The epilayers are grown from a Ga solvent in a graphite boat in a pure hydrogen atmosphere. Growth is started at a temperature of approximately 800 C. The best epilayers show a net-residual-donor concentration of 2 {times} 10{sup 13} cm{sup {minus}3}, confirmed by Hall effect measurements. The residual donors have been analyzed by far infrared spectroscopy and found to be sulfur and silicon. Epilayers with thicknesses of up to 120 {micro}m have been deposited on 650 {micro}m thick semi-insulating GaAs substrates and on 500 {micro}m thick n{sup +}-type GaAs substrates. The authors report the results obtained with Schottky barrier diodes fabricated from these high purity n-type GaAs epilayers and operated as X-ray detectors. The Schottky barrier contacts consisted of evaporated circular gold contacts on epilayers on n{sup +} substrates. The ohmic contacts were formed by evaporated and alloyed Ni-Ge-Au films on the back of the substrate. Several of the diodes exhibit currents of the order of 1 to 10 nA at reverse biases depleting approximately 50 {micro}m of the epilayer. This very encouraging result, demonstrating the possibility for fabricating GaAs p-i-n diodes with depletion layers in high purity GaAs instead of semi-insulating GaAs, is supported by similar results obtained by several other groups. The consequences of using high purity instead of semi-insulating GaAs will be much reduced charge carrier trapping. Diode electrical characteristics and detector performance results using {sup 55}Fe and {sup 241}Am radiation will be discussed.

  20. Development of radiation detectors based on hydrogenated amorphous silicon and its alloys

    SciTech Connect

    Hong, Wan-Shick

    1995-04-01

    Hydrogenated amorphous silicon and related materials have been applied to radiation detectors, utilizing their good radiation resistance and the feasibility of making deposits over a large area at low cost. Effects of deposition parameters on various material properties of a-Si:H have been studied to produce a material satisfying the requirements for specific detection application. Thick(-{approximately}50 {mu}m), device quality a-Si:H p-i-n diodes for direct detection of minimum ionizing particles have been prepared with low internal stress by a combination of low temperature growth, He-dilution of silane, and post annealing. The structure of the new film contained voids and tiny crystalline inclusions and was different from the one observed in conventional a-Si:H. Deposition on patterned substrates was attempted as an alternative to controlling deposition parameters to minimize substrate bending and delamination of thick a-Si:H films. Growth on an inversed-pyramid pattern reduced the substrate bending by a factor of 3{approximately}4 for the same thickness film. Thin (0.1 {approximately} 0.2 {mu}m) films of a-Si:H and a-SiC:H have been applied to microstrip gas chambers to control gain instabilities due to charges on the substrate. Light sensitivity of the a-Si:H sheet resistance was minimized and the surface resistivity was successfully` controlled in the range of 10{sup 12} {approximately} 10{sup 17} {Omega}/{four_gradient} by carbon alloying and boron doping. Performance of the detectors with boron-doped a-Si:C:H layers was comparable to that of electronic-conducting glass. Hydrogen dilution of silane has been explored to improve electrical transport properties of a-Si:H material for high speed photo-detectors and TFT applications.