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Sample records for hybrid germanium detector

  1. Calibration of germanium detectors

    International Nuclear Information System (INIS)

    Debertin, K.

    1983-01-01

    The process of determining the energy-dependent detection probability with measurements using Ge (Li) and high-grade germanium detectors is described. The paper explains which standards are best for a given purpose and given requirements as to accuracy, and how to assess measuring geometry variations and summation corrections. (DG) [de

  2. Calibration of germanium detectors

    International Nuclear Information System (INIS)

    Bjurman, B.; Erlandsson, B.

    1985-01-01

    This paper describes problems concerning the calibration of germanium detectors for the measurement of gamma-radiation from environmental samples. It also contains a brief description of some ways of reducing the uncertainties concerning the activity determination. These uncertainties have many sources, such as counting statistics, full energy peak efficiency determination, density correction and radionuclide specific-coincidence effects, when environmental samples are investigated at close source-to-detector distances

  3. Lithium germanium detectors reactivation

    International Nuclear Information System (INIS)

    Nicolai, J.A.; Marti, G.V.; Riso, J.M.; Gimenez, C.R.

    1981-01-01

    A convenient method to regenerate the characteristics of damaged Ge(li) detectors, that has been applied in the authors' laboratory, is described. The procedure consists in warming-up the crystal in its cryostat to temperatures between 10 deg C and 30 deg C above room temperature, in order to clean its surface. Subsequent cooling down to liquid nitrogen temperature, followed by one or more clean-up drifting processes, are applied to the crystals. This paper summarizes the results obtained with several detectors; this method was applied successfully to 15 detectors more. (author) [es

  4. Array of germanium detectors for nuclear safeguards

    International Nuclear Information System (INIS)

    Moss, C.E.; Bernard, W.; Dowdy, E.J.; Garcia, C.; Lucas, M.C.; Pratt, J.C.

    1983-01-01

    Our gamma-ray spectrometer system, designed for field use, offers high efficiency and high resolution for safeguards applications. The system consists of three 40% high-purity germanium detectors and a LeCroy 3500 data-acquisition system that calculates a composite spectrum for the three detectors. The LeCroy 3500 mainframe can be operated remotely from the detector array with control exercised through moderns and the telephone system. System performance with a mixed source of 125 Sb, 154 Eu, and 155 Eu confirms the expected efficiency of 120% with an overall resolution that is between the resolution of the best detector and that of the worst

  5. Modeling an array of encapsulated germanium detectors

    International Nuclear Information System (INIS)

    Kshetri, R

    2012-01-01

    A probability model has been presented for understanding the operation of an array of encapsulated germanium detectors generally known as composite detector. The addback mode of operation of a composite detector has been described considering the absorption and scattering of γ-rays. Considering up to triple detector hit events, we have obtained expressions for peak-to-total and peak-to-background ratios of the cluster detector, which consists of seven hexagonal closely packed encapsulated HPGe detectors. Results have been obtained for the miniball detectors comprising of three and four seven hexagonal closely packed encapsulated HPGe detectors. The formalism has been extended to the SPI spectrometer which is a telescope of the INTEGRAL satellite and consists of nineteen hexagonal closely packed encapsulated HPGe detectors. This spectrometer comprises of twelve detector modules surrounding the cluster detector. For comparison, we have considered a spectrometer comprising of nine detector modules surrounding the three detector configuration of miniball detector. In the present formalism, the operation of these sophisticated detectors could be described in terms of six probability amplitudes only. Using experimental data on relative efficiency and fold distribution of cluster detector as input, the fold distribution and the peak-to-total, peak-to-background ratios have been calculated for the SPI spectrometer and other composite detectors at 1332 keV. Remarkable agreement between experimental data and results from the present formalism has been observed for the SPI spectrometer.

  6. Electromechanically cooled germanium radiation detector system

    International Nuclear Information System (INIS)

    Lavietes, Anthony D.; Joseph Mauger, G.; Anderson, Eric H.

    1999-01-01

    We have successfully developed and fielded an electromechanically cooled germanium radiation detector (EMC-HPGe) at Lawrence Livermore National Laboratory (LLNL). This detector system was designed to provide optimum energy resolution, long lifetime, and extremely reliable operation for unattended and portable applications. For most analytical applications, high purity germanium (HPGe) detectors are the standard detectors of choice, providing an unsurpassed combination of high energy resolution performance and exceptional detection efficiency. Logistical difficulties associated with providing the required liquid nitrogen (LN) for cooling is the primary reason that these systems are found mainly in laboratories. The EMC-HPGe detector system described in this paper successfully provides HPGe detector performance in a portable instrument that allows for isotopic analysis in the field. It incorporates a unique active vibration control system that allows the use of a Sunpower Stirling cycle cryocooler unit without significant spectral degradation from microphonics. All standard isotopic analysis codes, including MGA and MGA++, GAMANL, GRPANL and MGAU, typically used with HPGe detectors can be used with this system with excellent results. Several national and international Safeguards organisations including the International Atomic Energy Agency (IAEA) and U.S. Department of Energy (DOE) have expressed interest in this system. The detector was combined with custom software and demonstrated as a rapid Field Radiometric Identification System (FRIS) for the U.S. Customs Service . The European Communities' Safeguards Directorate (EURATOM) is field-testing the first Safeguards prototype in their applications. The EMC-HPGe detector system design, recent applications, and results will be highlighted

  7. Detector materials: germanium and silicon

    International Nuclear Information System (INIS)

    Haller, E.E.

    1981-11-01

    This article is a summary of a short course lecture given in conjunction with the 1981 Nuclear Science Symposium. The basic physical properties of elemental semiconductors are reviewed. The interaction of energetic radiation with matter is discussed in order to develop a feeling for the appropriate semiconductor detector dimensions. The extremely low net dopant concentrations which are required are derived directly from the detector dimensions. A survey of the more recent techniques which have been developed for the analysis of detector grade semiconductor single crystals is presented

  8. Experience from operating germanium detectors in GERDA

    Science.gov (United States)

    Palioselitis, Dimitrios; GERDA Collaboration

    2015-05-01

    Phase I of the Germanium Detector Array (GERDA) experiment, searching for the neutrinoless double beta (0νββ) decay of 76Ge, was completed in September 2013. The most competitive half-life lower limit for the 0νββ decay of 76Ge was set (T-0ν1/2 > 2.1 · 1025 yr at 90% C.L.). GERDA operates bare Ge diodes immersed in liquid argon. During Phase I, mainly refurbished semi-coaxial high purity Ge detectors from previous experiments were used. The experience gained with handling and operating bare Ge diodes in liquid argon, as well as the stability and performance of the detectors during GERDA Phase I are presented. Thirty additional new enriched BEGe-type detectors were produced and will be used in Phase II. A subgroup of these detectors has already been used successfully in GERDA Phase I. The present paper gives an overview of the production chain of the new germanium detectors, the steps taken to minimise the exposure to cosmic radiation during manufacturing, and the first results of characterisation measurements in vacuum cryostats.

  9. Experience from operating germanium detectors in GERDA

    International Nuclear Information System (INIS)

    Palioselitis, Dimitrios

    2015-01-01

    Phase I of the Germanium Detector Array (GERDA) experiment, searching for the neutrinoless double beta (0νββ) decay of 76 Ge, was completed in September 2013. The most competitive half-life lower limit for the 0νββ decay of 76 Ge was set (T- 0ν 1/2 > 2.1 · 10 25 yr at 90% C.L.). GERDA operates bare Ge diodes immersed in liquid argon. During Phase I, mainly refurbished semi-coaxial high purity Ge detectors from previous experiments were used. The experience gained with handling and operating bare Ge diodes in liquid argon, as well as the stability and performance of the detectors during GERDA Phase I are presented. Thirty additional new enriched BEGe-type detectors were produced and will be used in Phase II. A subgroup of these detectors has already been used successfully in GERDA Phase I. The present paper gives an overview of the production chain of the new germanium detectors, the steps taken to minimise the exposure to cosmic radiation during manufacturing, and the first results of characterisation measurements in vacuum cryostats. (paper)

  10. Cryogenic readout techniques for germanium detectors

    Energy Technology Data Exchange (ETDEWEB)

    Benato, G. [University of Zurich, (Switzerland); Cattadori, C. [INFN - Milano Bicocca, (Italy); Di Vacri, A. [INFN LNGS, (Italy); Ferri, E. [Universita Milano Bicocca/INFN Milano Bicocca, (Italy); D' Andrea, V.; Macolino, C. [GSSI/INFN LNGS, (Italy); Riboldi, S. [Universita degli Studi di Milano/INFN Milano, (Italy); Salamida, F. [Universita Milano Bicocca/INFN Milano Bicocca, (Italy)

    2015-07-01

    High Purity Germanium detectors are used in many applications, from nuclear and astro-particle physics, to homeland security or environment protection. Although quite standard configurations are often used, with cryostats, charge sensitive amplifiers and analog or digital acquisition systems all commercially available, it might be the case that a few specific applications, e.g. satellites, portable devices, cryogenic physics experiments, etc. also require the development of a few additional or complementary techniques. An interesting case is for sure GERDA, the Germanium Detector Array experiment, searching for neutrino-less double beta decay of {sup 76}Ge at the Gran Sasso National Laboratory of INFN - Italy. In GERDA the entire detector array, composed of semi-coaxial and BEGe naked crystals, is operated suspended inside a cryostat filled with liquid argon, that acts not only as cooling medium and but also as an active shield, thanks to its scintillation properties. These peculiar circumstances, together with the additional requirement of a very low radioactive background from all the materials adjacent to the detectors, clearly introduce significant constraints on the design of the Ge front-end readout electronics. All the Ge readout solutions developed within the framework of the GERDA collaboration, for both Phase I and Phase II, will be briefly reviewed, with their relative strength and weakness compared together and with respect to ideal Ge readout. Finally, the digital processing techniques developed by the GERDA collaboration for energy estimation of Ge detector signals will be recalled. (authors)

  11. Germanium detectors and natural radioactivity in food

    Energy Technology Data Exchange (ETDEWEB)

    Garbini, Lucia [Max-Planck-Institut fuer Physik, Muenchen (Germany); Collaboration: GeDet-Collaboration

    2013-07-01

    Potassium is a very important mineral for many physiological processes, like fluid balance, protein synthesis and signal transmission in nerves. Many aliments like raisins, bananas or chocolate contain potassium. Natural potassium contains 0.012% of the radioactive isotope Potassium 40. This isotope decays via β{sup +} decay into a metastable state of Argon 40, which reaches its ground state emitting a gamma of 1460 keV. A commercially produced Germanium detector has been used to measure the energy spectra of different selected food samples. It was calibrated with KCl and potassium contents were extracted. Results verify the high potassium content of commonly recommended food samples. However, the measurement quantitatively differ from the expectations in several cases. One of the most interesting results concerns chocolate bars with different percentages of cacao.

  12. Development of revitalisation technique for impaired lithium doped germanium detector

    International Nuclear Information System (INIS)

    Singh, N.S.B.; Rafi Ahmed, A.G.; Balasubramanian, G.R.

    1994-01-01

    Semiconductor detectors play very significant role in photon detection and are important tools in the field of gamma spectroscopy. Lithium doped germanium detectors belong to this category. The development of revitalisation technique for these impaired detectors are discussed in this report

  13. Pulse shapes and surface effects in segmented germanium detectors

    International Nuclear Information System (INIS)

    Lenz, Daniel

    2010-01-01

    It is well established that at least two neutrinos are massive. The absolute neutrino mass scale and the neutrino hierarchy are still unknown. In addition, it is not known whether the neutrino is a Dirac or a Majorana particle. The GERmanium Detector Array (GERDA) will be used to search for neutrinoless double beta decay of 76 Ge. The discovery of this decay could help to answer the open questions. In the GERDA experiment, germanium detectors enriched in the isotope 76 Ge are used as source and detector at the same time. The experiment is planned in two phases. In the first, phase existing detectors are deployed. In the second phase, additional detectors will be added. These detectors can be segmented. A low background index around the Q value of the decay is important to maximize the sensitivity of the experiment. This can be achieved through anti-coincidences between segments and through pulse shape analysis. The background index due to radioactive decays in the detector strings and the detectors themselves was estimated, using Monte Carlo simulations for a nominal GERDA Phase II array with 18-fold segmented germanium detectors. A pulse shape simulation package was developed for segmented high-purity germanium detectors. The pulse shape simulation was validated with data taken with an 19-fold segmented high-purity germanium detector. The main part of the detector is 18-fold segmented, 6-fold in the azimuthal angle and 3-fold in the height. A 19th segment of 5mm thickness was created on the top surface of the detector. The detector was characterized and events with energy deposited in the top segment were studied in detail. It was found that the metalization close to the end of the detector is very important with respect to the length of the of the pulses observed. In addition indications for n-type and p-type surface channels were found. (orig.)

  14. Pulse shapes and surface effects in segmented germanium detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lenz, Daniel

    2010-03-24

    It is well established that at least two neutrinos are massive. The absolute neutrino mass scale and the neutrino hierarchy are still unknown. In addition, it is not known whether the neutrino is a Dirac or a Majorana particle. The GERmanium Detector Array (GERDA) will be used to search for neutrinoless double beta decay of {sup 76}Ge. The discovery of this decay could help to answer the open questions. In the GERDA experiment, germanium detectors enriched in the isotope {sup 76}Ge are used as source and detector at the same time. The experiment is planned in two phases. In the first, phase existing detectors are deployed. In the second phase, additional detectors will be added. These detectors can be segmented. A low background index around the Q value of the decay is important to maximize the sensitivity of the experiment. This can be achieved through anti-coincidences between segments and through pulse shape analysis. The background index due to radioactive decays in the detector strings and the detectors themselves was estimated, using Monte Carlo simulations for a nominal GERDA Phase II array with 18-fold segmented germanium detectors. A pulse shape simulation package was developed for segmented high-purity germanium detectors. The pulse shape simulation was validated with data taken with an 19-fold segmented high-purity germanium detector. The main part of the detector is 18-fold segmented, 6-fold in the azimuthal angle and 3-fold in the height. A 19th segment of 5mm thickness was created on the top surface of the detector. The detector was characterized and events with energy deposited in the top segment were studied in detail. It was found that the metalization close to the end of the detector is very important with respect to the length of the of the pulses observed. In addition indications for n-type and p-type surface channels were found. (orig.)

  15. Program LEPS to addition of gamma spectra from germanium detectors

    International Nuclear Information System (INIS)

    Romero, L.

    1986-01-01

    The LEP program, written in FORTRAN IV, performs the addition of two spectra, collected with different detectors, from the same sample. This application, adds the two gamma spectra obtained from two opposite LEPS Germanium Detectors (Low Energy Photon Spectrometer), correcting the differences (channel/energy) between both two spectra, and fitting them before adding. The total-spectrum is recorded at the computer memory as a single spectrum. The necessary equipment, to run this program is: - Two opposite germanium detectors, with their associate electronics. - Multichannel analyzer (2048 memory channel minimum) - Computer on-line interfacing to multichannel analyzer. (Author) 4 refs

  16. Event timing in high purity germanium coaxial detectors

    International Nuclear Information System (INIS)

    El-Ibiary, M.Y.

    1979-08-01

    The timing of gamma ray radiation in systems using high purity coaxial germanium detectors is analyzed and compared to that of systems using Ge(Li) detectors. The analysis takes into account the effect of the residual impurities on the electric field distribution, and hence on the rate of rise of the electrical pulses delivered to the timing module. Conditions under which the electric field distribution could lead to an improvement in timing performance, are identified. The results of the analysis confirm the experimental results published elsewhere and when compared with those for Ge(Li) detectors, which usually operate under conditions of charge carrier velocity saturation, confirm that high purity germanium detectors need not have inferior timing characteristics. A chart is given to provide a quantitative basis on which the trade off between the radius of the detector and its time resolution may be made

  17. Germanium detector studies in the framework of the GERDA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Budjas, Dusan

    2009-05-06

    The GERmanium Detector Array (GERDA) is an ultra-low background experiment under construction at Laboratori Nazionali del Gran Sasso. GERDA will search for {sup 76}Ge neutrinoless double beta decay with an aim for 100-fold reduction in background compared to predecessor experiments. This ambition necessitates innovative design approaches, strict selection of low-radioactivity materials, and novel techniques for active background suppression. The core feature of GERDA is its array of germanium detectors for ionizing radiation, which are enriched in {sup 76}Ge. Germanium detectors are the central theme of this dissertation. The first part describes the implementation, testing, and optimisation of Monte Carlo simulations of germanium spectrometers, intensively involved in the selection of low-radioactivity materials. The simulations are essential for evaluations of the gamma ray measurements. The second part concerns the development and validation of an active background suppression technique based on germanium detector signal shape analysis. This was performed for the first time using a BEGe-type detector, which features a small read-out electrode. As a result of this work, BEGe is now one of the two detector technologies included in research and development for the second phase of the GERDA experiment. A suppression of major GERDA backgrounds is demonstrated, with (0.93{+-}0.08)% survival probability for events from {sup 60}Co, (21{+-}3)% for {sup 226}Ra, and (40{+-}2)% for {sup 228}Th. The acceptance of {sup 228}Th double escape events, which are analogous to double beta decay, was kept at (89{+-}1)%. (orig.)

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

    Science.gov (United States)

    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.

  19. Mechanically-cooled germanium detector using two stirling refrigerators

    International Nuclear Information System (INIS)

    Katagiri, Masaki; Kobayashi, Yoshii; Takahashi, Koji

    1996-01-01

    In this paper, we present a developed mechanically-cooled germanium gamma-ray detector using Stirling refrigerators. Two Stirling refrigerators having cooling faculty of 1.5W at 80K were used to cool down a germanium detector element to 77K instead of a dewar containing liquid nitrogen. An 145cm 3 (56.0mmf x 59.1 mml) closed-end Ge(I) detector having relative detection efficiency of 29.4% was attached at the refrigerators. The size of the detector was 60cml x 15cmh x 15cmw. The lowest cooling temperature, 70K was obtained after 8 hours operation. The energy resolutions for 1.33MeV gamma-rays and for pulser signals were 2.43keV and 1.84keV at an amplifier shaping time of 2μsec, respectively

  20. The germanium wall of the GEM detector system GEM Collaboration

    International Nuclear Information System (INIS)

    Betigeri, M.; Biakowski, E.; Bojowald, H.; Budzanowski, A.; Chatterjee, A.; Drochner, M.; Ernst, J.; Foertsch, S.; Freindl, L.; Frekers, D.; Garske, W.; Grewer, K.; Hamacher, A.; Igel, S.; Ilieva, J.; Jarczyk, L.; Jochmann, M.; Kemmerling, G.; Kilian, K.; Kliczewski, S.; Klimala, W.; Kolev, D.; Kutsarova, T.; Lieb, J.; Lippert, G.; Machner, H.; Magiera, A.; Nann, H.; Pentchev, L.; Plendl, H.S.; Protic, D.; Razen, B.; Rossen, P. von; Roy, B.J.; Siudak, R.; Smyrski, J.; Srikantiah, R.V.; Strzakowski, A.; Tsenov, R.; Zolnierczuk, P.A.; Zwoll, K.

    1999-01-01

    A stack of annular detectors made of high-purity germanium was developed. The detectors are position sensitive with radial structures. The first one ('Quirl') is double-sided position sensitive defining 40,000 pixels, the following three (E1, E2 and E3) have 32 wedges each. The Quirl acts as tracker while the other three act as calorimeter. The stack was successfully operated in meson production reactions close to threshold

  1. Performance of a Small Anode Germanium Well detector

    International Nuclear Information System (INIS)

    Adekola, A.S.; Colaresi, J.; Douwen, J.; Mueller, W.F.; Yocum, K.M.

    2015-01-01

    The performance of Small Anode Germanium (SAGe) Well detector [1] has been evaluated for a range of sample sizes and geometries counted inside the well, on the end cap or in Marinelli beakers. The SAGe Well is a new type of low capacitance germanium well detector manufactured using small anode technology. The detector has similar energy resolution performance to semi-planar detectors, and offers significant improvement over the Coaxial and existing Well detectors. Resolution performance of 0.75 keV Full Width at Half Maxiumum (FWHM) at 122 keV γ-ray energy and resolution of 2.0–2.3 keV FWHM at 1332 keV γ-ray energy are guaranteed. Such outstanding resolution performance will benefit environmental applications in revealing the detailed radionuclide content of samples, particularly at low energy, and will enhance the detection sensitivity resulting in reduced counting time. This paper reports the counting performance of SAGe Well detector for range of sample sizes and geometries and how it compares to other detector types

  2. Performance of a Small Anode Germanium Well detector

    Energy Technology Data Exchange (ETDEWEB)

    Adekola, A.S., E-mail: aderemi.adekola@canberra.com; Colaresi, J.; Douwen, J.; Mueller, W.F.; Yocum, K.M.

    2015-06-01

    The performance of Small Anode Germanium (SAGe) Well detector [1] has been evaluated for a range of sample sizes and geometries counted inside the well, on the end cap or in Marinelli beakers. The SAGe Well is a new type of low capacitance germanium well detector manufactured using small anode technology. The detector has similar energy resolution performance to semi-planar detectors, and offers significant improvement over the Coaxial and existing Well detectors. Resolution performance of 0.75 keV Full Width at Half Maxiumum (FWHM) at 122 keV γ-ray energy and resolution of 2.0–2.3 keV FWHM at 1332 keV γ-ray energy are guaranteed. Such outstanding resolution performance will benefit environmental applications in revealing the detailed radionuclide content of samples, particularly at low energy, and will enhance the detection sensitivity resulting in reduced counting time. This paper reports the counting performance of SAGe Well detector for range of sample sizes and geometries and how it compares to other detector types.

  3. Characterisation of the SmartPET planar Germanium detectors

    Energy Technology Data Exchange (ETDEWEB)

    Boston, H.C. [Department of Physics, University of Liverpool, Oliver Lodge Laboratory, Liverpool L69 7ZE (United Kingdom)], E-mail: H.C.Boston@liverpool.ac.uk; Boston, A.J.; Cooper, R.J.; Cresswell, J.; Grint, A.N.; Mather, A.R.; Nolan, P.J.; Scraggs, D.P.; Turk, G. [Department of Physics, University of Liverpool, Oliver Lodge Laboratory, Liverpool L69 7ZE (United Kingdom); Hall, C.J.; Lazarus, I. [CCLRC Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Berry, A.; Beveridge, T.; Gillam, J.; Lewis, R. [School of Physics and Materials Engineering, Monash University, Melbourne (Australia)

    2007-08-21

    Small Animal Reconstruction PET (SmartPET) is a project funded by the UK medical research council (MRC) to demonstrate proof of principle that Germanium can be utilised in Positron Emission Tomography (PET). The SmartPET demonstrator consists of two orthogonal strip High Purity Germanium (HPGe) planar detectors manufactured by ORTEC. The aim of the project is to produce images of an internal source with sub mm{sup 3} spatial resolution. Before this image can be achieved the detectors have to be fully characterised to understand the response at any given location to a {gamma}-ray interaction. This has been achieved by probing the two detectors at a number of specified points with collimated sources of various energies and strengths. A 1 mm diameter collimated beam of photons was raster scanned in 1 mm steps across the detector. Digital pulse shape data were recorded from all the detector channels and the performance of the detector for energy and position determination has been assessed. Data will be presented for the first SmartPET detector.

  4. Modeling the Efficiency of a Germanium Detector

    Science.gov (United States)

    Hayton, Keith; Prewitt, Michelle; Quarles, C. A.

    2006-10-01

    We are using the Monte Carlo Program PENELOPE and the cylindrical geometry program PENCYL to develop a model of the detector efficiency of a planar Ge detector. The detector is used for x-ray measurements in an ongoing experiment to measure electron bremsstrahlung. While we are mainly interested in the efficiency up to 60 keV, the model ranges from 10.1 keV (below the Ge absorption edge at 11.1 keV) to 800 keV. Measurements of the detector efficiency have been made in a well-defined geometry with calibrated radioactive sources: Co-57, Se-75, Ba-133, Am-241 and Bi-207. The model is compared with the experimental measurements and is expected to provide a better interpolation formula for the detector efficiency than simply using x-ray absorption coefficients for the major constituents of the detector. Using PENELOPE, we will discuss several factors, such as Ge dead layer, surface ice layer and angular divergence of the source, that influence the efficiency of the detector.

  5. Special Cryostats for Lithium Compensated Germanium Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lauber, A; Malmsten, B; Rosencrantz, B

    1968-05-15

    In many applications of Ge(Li) detectors an extreme design of the cryostat is desirable. One example is a coincidence or anticoincidence setup where the Ge(Li) detector is surrounded by one or several other detectors, usually Nal(Tl) crystals or plastic scintillators. To be usable in this arrangement the part of the cryostat containing the Ge(Li) detector should have the form of a long hood, with the detector placed at its very end. The diameter of the hood should be as small as detector dimensions permit. Excellent energy resolution and reasonably low liquid nitrogen consumption must be retained. Two cryostats fulfilling these conditions will be described. For the first cryostat emphasis lay on the reduction of the hood diameter to an absolute minimum; for the other incorporation of a device regulating the temperature of the cryostat surface was required. The difficulties encountered will be discussed; they were primarily connected with the necessity of combining minimum temperature loss at the detector position with extreme cryostat compactness and cold finger length. The incorporation of a cooled FET transistor in the cryostat will also be described. The gamma spectrometers using the cryostats gave resolutions down to 2.8 keV FWHM for the 1173 keV gamma line from Co 60 and 1.2 keV FWHM for the 122 keV line from Co 57.

  6. Environmental applications for an intrinsic germanium well detector

    International Nuclear Information System (INIS)

    Stegnar, P.; Eldridge, J.S.; Teasley, N.A.; Oakes, T.W.

    1984-01-01

    The overall performance of an intrinsic germanium well detector for 125 I measurements was investigated in a program of environmental surveillance. Concentrations of 125 I and 131 I were determined in thyroids of road-killed deer showing the highest activities of 125 I in the animals from the near vicinity of Oak Ridge National Laboratory. This demonstrates the utility of road-killed deer as a bioindicator for radioiodine around nuclear facilities

  7. Environmental applications for an intrinsic germanium well detector

    International Nuclear Information System (INIS)

    Stegnar, P.; Eldridge, J.S.; Teasley, N.A.; Oakes, T.W.

    1984-01-01

    The overall performance of an intrinsic germanium well detector for 125 I measurements was investigated in a program of environmental surveillance. Concentrations of 125 I and 131 I were determined in thyroids of road-killed deer showing the highest activities of 125 I in the animals from the near vicinity of Oak Ridge National Laboratory. This demonstrates the utility of road-killed deer as a bionindicator for radioiodine around nuclear facilities. 6 refs., 2 figs., 3 tabs

  8. Environmental applications for an intrinsic germanium well detector

    International Nuclear Information System (INIS)

    Stegnar, P.; Eldridge, J.S.; Teasley, N.A.; Oakes, T.W.

    1983-01-01

    The overall performance of an intrinsic germanium well detector for 125 I measurements was investigated in a program of environmental surveillance. Concentrations of 125 I and 131 I were determined in thyroids of road-killed deer showing the highest activities of 125 I in the animals from the near vicinity of Oak Ridge National Laboratory. This demonstrates the utility of road-killed deer as a bioindicator for radioiodine around nuclear facilities. 6 refs., 2 figs., 3 tabs

  9. Trace radioactive measurement in foodstuffs using high purity germanium detector

    International Nuclear Information System (INIS)

    Morco, Ryan P.; Racho, Joseph Michael D.; Castaneda, Soledad S.; Almoneda, Rosalina V.; Pabroa, Preciosa Corazon B.; Sucgang, Raymond J.

    2010-01-01

    Trace radioactivity in food has been seriously considered sources of potential harm after the accidental radioactive releases in the last decades which led to contamination of the food chain. Countermeasures are being used to reduce the radiological health risk to the population and to ensure that public safety and international commitments are met. Investigation of radioactive traces in foods was carried out by gamma-ray spectrometry. The radionuclides being measured were fission products 1 37Cs and 1 34Cs and naturally occurring 4 0Κ. Gamma-ray measurements were performed using a hybrid gamma-ray counting system with coaxial p-type Tennelec High Purity Germanium (HPGe) detector with relative efficiency of 18.4%. Channels were calibrated to energies using a standard check source with 1 37Cs and 6 0Co present. Self-shielding within samples was taken into account by comparing directly with reference standards of similar matrix and geometry. Efficiencies of radionuclides of interests were accounted in calculating the activity concentrations in the samples. Efficiency calibration curve was generated using an in-house validated program called FINDPEAK, a least-square method that fits a polynomial up to sixth-order of equation. Lower Limits of Detection (LLD) obtained for both 1 37Cs and 1 34Cs ranges from 1-6 Bq/Kg depending on the sample matrix. In the last five years, there have been no foodstuffs analyzed exceeded the local and international regulatory limit of 1000Bq/Kg for the summed activities of 1 37Cs and 1 34Cs. (author)

  10. Germanium blocked impurity band far infrared detectors

    International Nuclear Information System (INIS)

    Rossington, C.S.

    1988-04-01

    The infrared portion of the electromagnetic spectrum has been of interest to scientist since the eighteenth century when Sir William Herschel discovered the infrared as he measured temperatures in the sun's spectrum and found that there was energy beyond the red. In the late nineteenth century, Thomas Edison established himself as the first infrared astronomer to look beyond the solar system when he observed the star Arcturus in the infrared. Significant advances in infrared technology and physics, long since Edison's time, have resulted in many scientific developments, such as the Infrared Astronomy Satellite (IRAS) which was launched in 1983, semiconductor infrared detectors for materials characterization, military equipment such as night-vision goggles and infrared surveillance equipment. It is now planned that cooled semiconductor infrared detectors will play a major role in the ''Star Wars'' nuclear defense scheme proposed by the Reagan administration

  11. Fast neutron damage in germanium detectors

    International Nuclear Information System (INIS)

    Kraner, H.W.

    1979-10-01

    The effects of fast neutron radiation damage on the performance of both Ge(Li) and Ge(HP) detectors have been studied during the past decade and will be summarized. A review of the interaction processes leading to the defect structures causing trapping will be made. The neutron energy dependence of observable damage effects will be considered in terms of interaction and defect production cross sections

  12. The Future of Low Temperature Germanium as Dark Matter Detectors

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    The Weakly Interactive Massive Particles (WIMPs) represent one of the most attractive candidates for the dark matter in the universe. With the combination of experiments attempting to detect WIMP scattering in the laboratory, of searches for their annihilation in the cosmos and of their potential production at the LHC, the next five years promise to be transformative. I will review the role played so far by low temperature germanium detectors in the direct detection of WIMPs. Because of its high signal to noise ratio, the simultaneous measurement of athermal phonons and ionization is so far the only demonstrated approach with zero-background. I will argue that this technology can be extrapolated to a target mass of the order of a tonne at reasonable cost and can keep playing a leading role, complementary to noble liquid technologies. I will describe in particular GEODM, the proposed Germanium Observatory for Dark Matter at the US Deep Underground Science and Engineering Laboratory (DUSEL).

  13. Gamma ray polarimetry using a position sensitive germanium detector

    CERN Document Server

    Kroeger, R A; Kurfess, J D; Phlips, B F

    1999-01-01

    Imaging gamma-ray detectors make sensitive polarimeters in the Compton energy regime by measuring the scatter direction of gamma rays. The principle is to capitalize on the angular dependence of the Compton scattering cross section to polarized gamma rays and measure the distribution of scatter directions within the detector. This technique is effective in a double-sided germanium detector between roughly 50 keV and 1 MeV. This paper reviews device characteristics important to the optimization of a Compton polarimeter, and summarizes measurements we have made using a device with a 5x5 cm active area, 1 cm thickness, and strip-electrodes on a 2 mm pitch.

  14. Self-absorption corrections for well-type germanium detectors

    International Nuclear Information System (INIS)

    Appleby, P.G.; Richardson, N.; Nolan, P.J.

    1992-01-01

    Corrections for self-absorption are of vital importance to accurate determination by gamma spectrometry of radionuclides such as 210 Pb, 241 Am and 234 Th which emit low energy gamma radiation. A simple theoretical model for determining the necessary corrections for well-type germanium detectors is presented. In this model, self-absorption factors are expressed in terms of the mass attenuation coefficient of the sample and a parameter characterising the well geometry. Experimental measurements of self-absorption are used to evaluate the model and to determine a semi-empirical algorithm for improved estimates of the geometrical parameter. (orig.)

  15. Automation of the Characterization of High Purity Germanium Detectors

    Science.gov (United States)

    Dugger, Charles ``Chip''

    2014-09-01

    Neutrinoless double beta decay is a rare hypothesized process that may yield valuable insight into the fundamental properties of the neutrino. Currently there are several experiments trying to observe this process, including the Majorana DEMONSTRAOR experiment, which uses high purity germanium (HPGe) detectors to generate and search for these events. Because the event happens internally, it is essential to have the lowest background possible. This is done through passive detector shielding, as well as event discrimination techniques that distinguish between multi-site events characteristic of gamma-radiation, and single-site events characteristic of neutrinoless double beta decay. Before fielding such an experiment, the radiation response of the detectors must be characterized. A robotic arm is being tested for future calibration of HPGe detectors. The arm will hold a source at locations relative to the crystal while data is acquired. Several radioactive sources of varying energy levels will be used to determine the characteristics of the crystal. In this poster, I will present our work with the robot, as well as the characterization of data we took with an underground HPGe detector at the WIPP facility in Carlsbad, NM (2013). Neutrinoless double beta decay is a rare hypothesized process that may yield valuable insight into the fundamental properties of the neutrino. Currently there are several experiments trying to observe this process, including the Majorana DEMONSTRAOR experiment, which uses high purity germanium (HPGe) detectors to generate and search for these events. Because the event happens internally, it is essential to have the lowest background possible. This is done through passive detector shielding, as well as event discrimination techniques that distinguish between multi-site events characteristic of gamma-radiation, and single-site events characteristic of neutrinoless double beta decay. Before fielding such an experiment, the radiation response of

  16. Performance of a 6x6 segmented germanium detector for {gamma}-ray tracking

    Energy Technology Data Exchange (ETDEWEB)

    Valiente-Dobon, J.J. E-mail: j.valiente-dobon@surrey.ac.uk; Pearson, C.J.; Regan, P.H.; Sellin, P.J.; Gelletly, W.; Morton, E.; Boston, A.; Descovich, M.; Nolan, P.J.; Simpson, J.; Lazarus, I.; Warner, D

    2003-06-01

    A 36 fold segmented germanium coaxial detector has been supplied by EURISYS MESURES. The outer contact is segmented both radially and longitudinally. The signals from the fast preamplifiers have been digitised by 12 bit, 40 MHz ADCs. In this article we report preliminary results obtained using this detector and their relevance for future germanium {gamma}-ray tracking arrays.

  17. Charge Spreading and Position Sensitivity in a Segmented Planar Germanium Detector (Preprint)

    National Research Council Canada - National Science Library

    Kroeger, R. A; Gehrels, N; Johnson, W. N; Kurfess, J. D; Phlips, B. P; Tueller, J

    1998-01-01

    The size of the charge cloud collected in a segmented germanium detector is limited by the size of the initial cloud, uniformity of the electric field, and the diffusion of electrons and holes through the detector...

  18. Germanium microstrip detectors with 50 and 100 μm pitch

    International Nuclear Information System (INIS)

    Amendolia, S.R.; Bedeschi, F.; Bertolucci, E.; Bettoni, D.; Bosisio, L.; Bottigli, U.; Bradaschia, C.; Dell'Orso, M.; Fidecaro, F.; Foa, L.; Focardi, E.; Giannetti, P.; Giorgi, M.A.; Marrocchesi, P.S.; Menzione, A.; Raso, G.; Ristori, L.; Scribano, A.; Stefanini, A.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Haller, E.E.; Hansen, W.L.; Luke, P.N.

    1984-01-01

    Multi-electrode germanium detectors are being used as an active target for decay path measurements of charmed mesons. The procedure used to fabricate such detectors is described and a brief analysis of their performance is given. (orig.)

  19. Induced Radioactivity Measured in a Germanium Detector After a Long Duration Balloon Flight

    Science.gov (United States)

    Starr, R.; Evans, L. G.; Floyed, S. R.; Drake, D. M.; Feldman, W. C.; Squyres, S. W.; Rester, A. C.

    1997-01-01

    A 13-day long duration balloon flight carrying a germanium detector was flown from Williams Field, Antartica in December 1992. After recovery of the payload the activity induced in the detector was measured.

  20. Strip interpolation in silicon and germanium strip detectors

    International Nuclear Information System (INIS)

    Wulf, E. A.; Phlips, B. F.; Johnson, W. N.; Kurfess, J. D.; Lister, C. J.; Kondev, F.; Physics; Naval Research Lab.

    2004-01-01

    The position resolution of double-sided strip detectors is limited by the strip pitch and a reduction in strip pitch necessitates more electronics. Improved position resolution would improve the imaging capabilities of Compton telescopes and PET detectors. Digitizing the preamplifier waveform yields more information than can be extracted with regular shaping electronics. In addition to the energy, depth of interaction, and which strip was hit, the digitized preamplifier signals can locate the interaction position to less than the strip pitch of the detector by looking at induced signals in neighboring strips. This allows the position of the interaction to be interpolated in three dimensions and improve the imaging capabilities of the system. In a 2 mm thick silicon strip detector with a strip pitch of 0.891 mm, strip interpolation located the interaction of 356 keV gamma rays to 0.3 mm FWHM. In a 2 cm thick germanium detector with a strip pitch of 5 mm, strip interpolation of 356 keV gamma rays yielded a position resolution of 1.5 mm FWHM

  1. HEROICA: A fast screening facility for the characterization of germanium detectors

    Energy Technology Data Exchange (ETDEWEB)

    Andreotti, Erica [Universität Tübingen, Auf der Morgenstelle 14, 72076 Tübingen (Germany); Collaboration: GERDA Collaboration

    2013-08-08

    In the course of 2012, a facility for the fast screening of germanium detectors called HEROICA (Hades Experimental Research Of Intrinsic Crystal Appliances) has been installed at the HADES underground laboratory in the premises of the Belgian Nuclear Research Centre SCK•CEN, in Mol (Belgium). The facility allows performing a complete characterization of the critical germanium detectors' operational parameters with a rate of about two detectors per week.

  2. TIGRESS highly-segmented high-purity germanium clover detector

    Science.gov (United States)

    Scraggs, H. C.; Pearson, C. J.; Hackman, G.; Smith, M. B.; Austin, R. A. E.; Ball, G. C.; Boston, A. J.; Bricault, P.; Chakrawarthy, R. S.; Churchman, R.; Cowan, N.; Cronkhite, G.; Cunningham, E. S.; Drake, T. E.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hyland, B.; Jones, B.; Leslie, J. R.; Martin, J.-P.; Morris, D.; Morton, A. C.; Phillips, A. A.; Sarazin, F.; Schumaker, M. A.; Svensson, C. E.; Valiente-Dobón, J. J.; Waddington, J. C.; Watters, L. M.; Zimmerman, L.

    2005-05-01

    The TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS) will consist of twelve units of four high-purity germanium (HPGe) crystals in a common cryostat. The outer contacts of each crystal will be divided into four quadrants and two lateral segments for a total of eight outer contacts. The performance of a prototype HPGe four-crystal unit has been investigated. Integrated noise spectra for all contacts were measured. Energy resolutions, relative efficiencies for both individual crystals and for the entire unit, and peak-to-total ratios were measured with point-like sources. Position-dependent performance was measured by moving a collimated source across the face of the detector.

  3. Timing of gamma rays in coaxial germanium detector systems

    International Nuclear Information System (INIS)

    El-Ibiary, M.Y.

    1979-01-01

    A study is reported on the timing uncertainty in gamma ray coaxial germanium detector systems. The work deals with the zero cross over method which is widely used to reduce the dependence of the instant of timing on the radiation energy absorbed and on the position within the detector at which absorption takes place. It is found that the amplitude risetime compensated (ARC) method gives, under normal conditions, the best resolution at a specific energy. For higher energies, the resolution improves and there is no shift of the mean instant of timing. The method is therefore well suited for wide energy coverage. The parameters involved in implementing an ARC system for optimum performance at a specific energy are identified in terms of the preamplifier noise level and risetime. A trade off can be made between the resolutions at high and at low energies. The time resolution attained is given by means of a series of charts which use normalized dimensionless variables for ready application to any given case. Lithium compensated Ge detectors which normally operate under conditions of velocity saturation of the charge carriers by applying sufficient bias voltage create an electric field in excess of 1 kV/cm throughout the depleted region. High purity Ge detectors where velocity saturation may not be reached within certain parts of the depleted region are studied. Special attention is given to the probability of pulses being incorrectly timed because of their slow rise or small magnitude. Such incorrect timing is energy-dependent and results in a noticeable distortion of the timing spectrum that relates to a wide energy range. Limitations on system parameters to keep the probability of incorrect timing below a specified fraction are given

  4. An Implant-Passivated Blocked Impurity Band Germanium Detector for the Far Infrared, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to investigate the feasibility of fabricating a germanium blocked-impurity-band (BIB) detector using a novel process which will enable us to: 1- fabricate...

  5. An Implant-Passivated Blocked Impurity Band Germanium Detector for the Far Infrared, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to fabricate a germanium blocked-impurity-band (BIB) detector using a novel process which will enable us to: 1- fabricate a suitably-doped active layer...

  6. PREFACE: 2nd Workshop on Germanium Detectors and Technologies

    Science.gov (United States)

    Abt, I.; Majorovits, B.; Keller, C.; Mei, D.; Wang, G.; Wei, W.

    2015-05-01

    The 2nd workshop on Germanium (Ge) detectors and technology was held at the University of South Dakota on September 14-17th 2014, with more than 113 participants from 8 countries, 22 institutions, 15 national laboratories, and 8 companies. The participants represented the following big projects: (1) GERDA and Majorana for the search of neutrinoless double-beta decay (0νββ) (2) SuperCDMS, EDELWEISS, CDEX, and CoGeNT for search of dark matter; (3) TEXONO for sub-keV neutrino physics; (4) AGATA and GRETINA for gamma tracking; (5) AARM and others for low background radiation counting; (5) as well as PNNL and LBNL for applications of Ge detectors in homeland security. All participants have expressed a strong desire on having better understanding of Ge detector performance and advancing Ge technology for large-scale applications. The purpose of this workshop was to leverage the unique aspects of the underground laboratories in the world and the germanium (Ge) crystal growing infrastructure at the University of South Dakota (USD) by brining researchers from several institutions taking part in the Experimental Program to Stimulate Competitive Research (EPSCoR) together with key leaders from international laboratories and prestigious universities, working on the forefront of the intensity to advance underground physics focusing on the searches for dark matter, neutrinoless double-beta decay (0νββ), and neutrino properties. The goal of the workshop was to develop opportunities for EPSCoR institutions to play key roles in the planned world-class research experiments. The workshop was to integrate individual talents and existing research capabilities, from multiple disciplines and multiple institutions, to develop research collaborations, which includes EPSCor institutions from South Dakota, North Dakota, Alabama, Iowa, and South Carolina to support multi-ton scale experiments for future. The topic areas covered in the workshop were: 1) science related to Ge

  7. Segmentation of the Outer Contact on P-Type Coaxial Germanium Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Hull, Ethan L.; Pehl, Richard H.; Lathrop, James R.; Martin, Gregory N.; Mashburn, R. B.; Miley, Harry S.; Aalseth, Craig E.; Hossbach, Todd W.

    2006-09-21

    Germanium detector arrays are needed for low-level counting facilities. The practical applications of such user facilities include characterization of low-level radioactive samples. In addition, the same detector arrays can also perform important fundamental physics measurements including the search for rare events like neutrino-less double-beta decay. Coaxial germanium detectors having segmented outer contacts will provide the next level of sensitivity improvement in low background measurements. The segmented outer detector contact allows performance of advanced pulse shape analysis measurements that provide additional background reduction. Currently, n-type (reverse electrode) germanium coaxial detectors are used whenever a segmented coaxial detector is needed because the outer boron (electron barrier) contact is thin and can be segmented. Coaxial detectors fabricated from p-type germanium cost less, have better resolution, and are larger than n-type coaxial detectors. However, it is difficult to reliably segment p-type coaxial detectors because thick (~1 mm) lithium-diffused (hole barrier) contacts are the standard outside contact for p-type coaxial detectors. During this Phase 1 Small Business Innovation Research (SBIR) we have researched the possibility of using amorphous germanium contacts as a thin outer contact of p-type coaxial detectors that can be segmented. We have developed amorphous germanium contacts that provide a very high hole barrier on small planar detectors. These easily segmented amorphous germanium contacts have been demonstrated to withstand several thousand volts/cm electric fields with no measurable leakage current (<1 pA) from charge injection over the hole barrier. We have also demonstrated that the contact can be sputter deposited around and over the curved outside surface of a small p-type coaxial detector. The amorphous contact has shown good rectification properties on the outside of a small p-type coaxial detector. These encouraging

  8. Overview of multi-element monolithic germanium detectors for XAFS experiments at diamond light source

    International Nuclear Information System (INIS)

    Chatterji, S.; Dennis, G. J.; Dent, A.; Diaz-Moreno, S.; Cibin, G.; Tartoni, N.; Helsby, W. I.

    2016-01-01

    An overview of multi-element monolithic germanium detectors being used at the X-ray absorption spectroscopy (XAS) beam lines at Diamond Light Source (DLS) is being reported. The hardware details and a summary of the performance of these detectors have also been provided. Recent updates about various ongoing projects being worked on to improve the performance of these detectors are summarized.

  9. Overview of multi-element monolithic germanium detectors for XAFS experiments at diamond light source

    Energy Technology Data Exchange (ETDEWEB)

    Chatterji, S.; Dennis, G. J.; Dent, A.; Diaz-Moreno, S.; Cibin, G.; Tartoni, N. [Diamond Light Source Ltd, Oxfordshire (United Kingdom); Helsby, W. I. [STFC Daresbury Laboratory, Warrington (United Kingdom)

    2016-07-27

    An overview of multi-element monolithic germanium detectors being used at the X-ray absorption spectroscopy (XAS) beam lines at Diamond Light Source (DLS) is being reported. The hardware details and a summary of the performance of these detectors have also been provided. Recent updates about various ongoing projects being worked on to improve the performance of these detectors are summarized.

  10. Germanium detectors for nuclear spectroscopy: Current research and development activity at LNL

    Energy Technology Data Exchange (ETDEWEB)

    Napoli, D. R., E-mail: daniel.r.napoli@lnl.infn.it [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro, Padova (Italy); Maggioni, G., E-mail: maggioni@lnl.infn.it; Carturan, S.; Gelain, M. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro, Padova (Italy); Department of Physics and Astronomy “G. Galilei”, University of Padova, Via Marzolo 8, 35121 Padova (Italy); Eberth, J. [Institut für Kernphysik, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln (Germany); Grimaldi, M. G.; Tatí, S. [Department of Physics and Astronomy, University of Catania (Italy); Riccetto, S. [University of Camerino and INFN of Perugia (Italy); Mea, G. Della [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro, Padova (Italy); University of Trento (Italy)

    2016-07-07

    High-purity Germanium (HPGe) detectors have reached an unprecedented level of sophistication and are still the best solution for high-resolution gamma spectroscopy. In the present work, we will show the results of the characterization of new surface treatments for the production of these detectors, studied in the framework of our multidisciplinary research program in HPGe detector technologies.

  11. Using of germanium detectors in nuclear experiments with photon beams

    International Nuclear Information System (INIS)

    Kapitonov, I.M.; Tutin, I.A.

    1995-01-01

    Full text: The study of atomic nuclei with real photons is very important source of the information about nuclear structure. In such experiments the basic electromagnetic interaction between the photon and the target nuclei is well known. Experiments with photon beams become especially valuable when outcoming particles are also photons. In these cases completely model-independent information on nuclear structure can be extracted. The use of semiconductor Ge-spectrometers with excellent resolution and large sensitive volumes for recording outcoming photons gives us such an additional important advantage as possibility to observe individual closely spaced levels of the final nuclei. In the report an experience of using Ge-detectors in two types of nuclear experiments is described. Both of them - nuclear resonance fluorescence (NRF) and nuclear photodisintegration - are carried out in beams of bremsstrahlung gamma radiation. The central element of the setup recording gamma quanta in these experiments is germanium detector. NRF is unique method for studying low-lying excited nuclear states. The spins of the states can be determined easily from the measured angular distributions of scattered photons. Model independent parity assignments in NRF can be achieved by measuring polarization observables. There are two experimental possibilities: the use of linearly polarized photons (off-axis bremsstrahlung) in the entrance channel and the measurement of the linear polarization of the scattered photons using Compton polarimeters. For both methods several germanium detectors (3-5) must be used simultaneously. Nowadays Compton polarimeter can also be done from single large Ge-crystal by segmenting the outer electrode. Advantages and drawbacks of the methods and background conditions are discussed and requirements to Ge-crystals are formulated. The importance of using a new generation of electron accelerators with continuous wave (cw) beams for NRF-measurements is stressed. The

  12. High bit rate germanium single photon detectors for 1310nm

    Science.gov (United States)

    Seamons, J. A.; Carroll, M. S.

    2008-04-01

    There is increasing interest in development of high speed, low noise and readily fieldable near infrared (NIR) single photon detectors. InGaAs/InP Avalanche photodiodes (APD) operated in Geiger mode (GM) are a leading choice for NIR due to their preeminence in optical networking. After-pulsing is, however, a primary challenge to operating InGaAs/InP single photon detectors at high frequencies1. After-pulsing is the effect of charge being released from traps that trigger false ("dark") counts. To overcome this problem, hold-off times between detection windows are used to allow the traps to discharge to suppress after-pulsing. The hold-off time represents, however, an upper limit on detection frequency that shows degradation beginning at frequencies of ~100 kHz in InGaAs/InP. Alternatively, germanium (Ge) single photon avalanche photodiodes (SPAD) have been reported to have more than an order of magnitude smaller charge trap densities than InGaAs/InP SPADs2, which allowed them to be successfully operated with passive quenching2 (i.e., no gated hold off times necessary), which is not possible with InGaAs/InP SPADs, indicating a much weaker dark count dependence on hold-off time consistent with fewer charge traps. Despite these encouraging results suggesting a possible higher operating frequency limit for Ge SPADs, little has been reported on Ge SPAD performance at high frequencies presumably because previous work with Ge SPADs has been discouraged by a strong demand to work at 1550 nm. NIR SPADs require cooling, which in the case of Ge SPADs dramatically reduces the quantum efficiency of the Ge at 1550 nm. Recently, however, advantages to working at 1310 nm have been suggested which combined with a need to increase quantum bit rates for quantum key distribution (QKD) motivates examination of Ge detectors performance at very high detection rates where InGaAs/InP does not perform as well. Presented in this paper are measurements of a commercially available Ge APD

  13. Techniques to distinguish between electron and photon induced events using segmented germanium detectors

    International Nuclear Information System (INIS)

    Kroeninger, K.

    2007-01-01

    Two techniques to distinguish between electron and photon induced events in germanium detectors were studied: (1) anti-coincidence requirements between the segments of segmented germanium detectors and (2) the analysis of the time structure of the detector response. An 18-fold segmented germanium prototype detector for the GERDA neutrinoless double beta-decay experiment was characterized. The rejection of photon induced events was measured for the strongest lines in 60 Co, 152 Eu and 228 Th. An accompanying Monte Carlo simulation was performed and the results were compared to data. An overall agreement with deviations of the order of 5-10% was obtained. The expected background index of the GERDA experiment was estimated. The sensitivity of the GERDA experiment was determined. Special statistical tools were developed to correctly treat the small number of events expected. The GERDA experiment uses a cryogenic liquid as the operational medium for the germanium detectors. It was shown that germanium detectors can be reliably operated through several cooling cycles. (orig.)

  14. Techniques to distinguish between electron and photon induced events using segmented germanium detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kroeninger, K.

    2007-06-05

    Two techniques to distinguish between electron and photon induced events in germanium detectors were studied: (1) anti-coincidence requirements between the segments of segmented germanium detectors and (2) the analysis of the time structure of the detector response. An 18-fold segmented germanium prototype detector for the GERDA neutrinoless double beta-decay experiment was characterized. The rejection of photon induced events was measured for the strongest lines in {sup 60}Co, {sup 152}Eu and {sup 228}Th. An accompanying Monte Carlo simulation was performed and the results were compared to data. An overall agreement with deviations of the order of 5-10% was obtained. The expected background index of the GERDA experiment was estimated. The sensitivity of the GERDA experiment was determined. Special statistical tools were developed to correctly treat the small number of events expected. The GERDA experiment uses a cryogenic liquid as the operational medium for the germanium detectors. It was shown that germanium detectors can be reliably operated through several cooling cycles. (orig.)

  15. Amorphous germanium as an electron or hole blocking contact on high-purity germanium detectors

    International Nuclear Information System (INIS)

    Hansen, W.L.; Haller, E.E.

    1976-10-01

    Experiments were performed in an attempt to make thin n + contacts on high-purity germanium by the solid phase/sup 1)/ epitaxial regrowth of arsenic doped amorphous germanium. After cleaning the crystal surface with argon sputtering and trying many combinations of layers, it was not found possible to induce recrystallization below 400 0 C. However, it was found that simple thermally evaporated amorphous Ge made fairly good electron or hole blocking contacts. Excellent spectrometers have been made with amorphous Ge replacing the n + contact. As presently produced, the amorphous Ge contact diodes show a large variation in high-voltage leakage current

  16. Analysis of the dead layer of a detector of germanium with code ultrapure Monte Carlo SWORD-GEANT; Analisis del dead layer de un detector de germanio ultrapuro con el codigo de Monte Carlo SWORDS-GEANT

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, S.; Querol, A.; Ortiz, J.; Rodenas, J.; Verdu, G.

    2014-07-01

    In this paper the use of Monte Carlo code SWORD-GEANT is proposed to simulate an ultra pure germanium detector High Purity Germanium detector (HPGe) detector ORTEC specifically GMX40P4, coaxial geometry. (Author)

  17. X-ray radiometric analysis of lead and zinc concentrates using germanium radiation detector

    International Nuclear Information System (INIS)

    Vajgachev, A.A.; Mamysh, V.A.; Mil'chakov, V.I.; Shchekin, K.I.; Berezkin, V.V.

    1975-01-01

    The results of determination of lead, zinc and iron in lead and zinc concentrates by the X-ray-radiometric method with the use of germanium semiconductor detector are presented. In the experiments the 57 Co source and tritium-zirconium target were used. The activity of 57 Co was 2 mc. The area of the germanium detector employed was 5g mm 2 , its thickness - 2.3 mm. In lead concentrates zinc and iron were determined from the direct intensity of K-series radiation. In the analysis of zinc concentrates the same conditions of recording and excitation were used as in the case of lead concentrates, but the measurements were conducted in saturated layers. It is demonstrated that the use of germanium semiconductor detectors in combination with the suggested methods of measurements makes it possible to perform determination of iron, zinc and lead in zinc and lead concentrates with permissible error

  18. Segmented Monolithic Germanium Detector Arrays for X-ray Absorption Spectroscopy. Final Report

    International Nuclear Information System (INIS)

    Hull, Ethan L.

    2011-01-01

    The experimental results from the Phase I effort were extremely encouraging. During Phase I PHDs Co. made the first strides toward a new detector technology that could have great impact on synchrotron x-ray absorption (XAS) measurements, and x-ray detector technology in general. Detector hardware that allowed critical demonstration measurements of our technology was designed and fabricated. This new technology allows good charge collection from many pixels on a single side of a multi-element monolithic germanium planar detector. The detector technology provides 'dot-like' collection electrodes having very low capacitance. The detector technology appears to perform as anticipated in the Phase I proposal. In particular, the 7-pixel detector studied showed remarkable properties; making it an interesting example of detector physics. The technology is enabled by the use of amorphous germanium contact technology on germanium planar detectors. Because of the scalability associated with the fabrication of these technologies at PHDs Co., we anticipate being able to supply larger detector systems at significantly lower cost than systems made in the conventional manner.

  19. Focusing of a new germanium counter type : the composite detector. Uses of the TREFLE detector in the EUROGAM multidetector

    International Nuclear Information System (INIS)

    Han, L.

    1995-05-01

    The aim of this thesis is the development of new types of germanium detectors: the composite detectors. Two types of prototypes are then conceived: the stacked planar detector (EDP) and the assembly of coaxial diodes (TREFLE). They are designed for the multidetector EUROGAM destined to the research of nuclear structure at high angular momentum. The four planar diodes of EDP detector were of 7 cm diameter and of 15 to 20 mm thick. The difference between the calculated and measured photopic efficiency is observed. The importance of surface channel induces a weak resistance of neutron damages. The sputtering method for the surface treatment reducing the germanium dead layer as well as a rule of selection concerning the impurity concentration and the thickness of crystal is helpful for the later production of germanium detector. The CLOVER detector consist of for mean size crystals in the same cryostat. The photopic efficiency is much larger than that of the greatest monocrystal detector. And the granulation of composite detector allowed the Doppler broadening correction of gamma ray observed in the nuclear reaction where the recoil velocity is very high. This new type of detector enable the linear polarization measurement of gamma ray. Twenty-four CLOVER detector are actually mounted in the EUROGAM array. The characteristics measured in source as well as in beam, reported in this thesis, meet exactly the charge account. (author). 47 refs., 61 figs., 18 tabs

  20. High-resolution imaging gamma-ray spectroscopy with externally segmented germanium detectors

    Science.gov (United States)

    Callas, J. L.; Mahoney, W. A.; Varnell, L. S.; Wheaton, W. A.

    1993-01-01

    Externally segmented germanium detectors promise a breakthrough in gamma-ray imaging capabilities while retaining the superb energy resolution of germanium spectrometers. An angular resolution of 0.2 deg becomes practical by combining position-sensitive germanium detectors having a segment thickness of a few millimeters with a one-dimensional coded aperture located about a meter from the detectors. Correspondingly higher angular resolutions are possible with larger separations between the detectors and the coded aperture. Two-dimensional images can be obtained by rotating the instrument. Although the basic concept is similar to optical or X-ray coded-aperture imaging techniques, several complicating effects arise because of the penetrating nature of gamma rays. The complications include partial transmission through the coded aperture elements, Compton scattering in the germanium detectors, and high background count rates. Extensive electron-photon Monte Carlo modeling of a realistic detector/coded-aperture/collimator system has been performed. Results show that these complicating effects can be characterized and accounted for with no significant loss in instrument sensitivity.

  1. Position resolution simulations for the inverted-coaxial germanium detector, SIGMA

    Science.gov (United States)

    Wright, J. P.; Harkness-Brennan, L. J.; Boston, A. J.; Judson, D. S.; Labiche, M.; Nolan, P. J.; Page, R. D.; Pearce, F.; Radford, D. C.; Simpson, J.; Unsworth, C.

    2018-06-01

    The SIGMA Germanium detector has the potential to revolutionise γ-ray spectroscopy, providing superior energy and position resolving capabilities compared with current large volume state-of-the-art Germanium detectors. The theoretical position resolution of the detector as a function of γ-ray interaction position has been studied using simulated detector signals. A study of the effects of RMS noise at various energies has been presented with the position resolution ranging from 0.33 mm FWHM at Eγ = 1 MeV, to 0.41 mm at Eγ = 150 keV. An additional investigation into the effects pulse alignment have on pulse shape analysis and in turn, position resolution has been performed. The theoretical performance of SIGMA operating in an experimental setting is presented for use as a standalone detector and as part of an ancillary system.

  2. A variable temperature cryostat that produces in situ clean-up germanium detector surfaces

    International Nuclear Information System (INIS)

    Pehl, R.H.; Madden, N.W.; Malone, D.F.; Cork, C.P.; Landis, D.A.; Xing, J.S.; Friesel, D.L.

    1988-11-01

    Variable temperature cryostats that can maintain germanium detectors at temperatures from 82 K to about 400 K while the thermal shield surrounding the detectors remains much colder when the detectors are warmed have been developed. Cryostats such as these offer the possibility of cryopumping material from the surface of detectors to the colder thermal shield. The diode characteristics of several detectors have shown very significant improvement following thermal cycles up to about 150 K in these cryostats. Important applications for cryostats having this attribute are many. 4 figs

  3. Dark Matter Search with sub-keV Germanium Detectors at the China Jinping Underground Laboratory

    International Nuclear Information System (INIS)

    Yue Qian; Wong, Henry T

    2012-01-01

    Germanium detectors with sub-keV sensitivities open a window to search for low-mass WIMP dark matter. The CDEX-TEXONO Collaboration is conducting the first research program at the new China Jinping Underground Laboratory with this approach. The status and plans of the laboratory and the experiment are discussed.

  4. Neutrino and dark matter physics with sub-keV germanium detectors

    Indian Academy of Sciences (India)

    2014-11-04

    Nov 4, 2014 ... Germanium detectors with sub-keV sensitivities open a window to study neutrino physics to search for light weakly interacting massive particle (WIMP) dark matter. We summarize the recent results on spin-independent couplings of light WIMPs from the TEXONO experiment at the Kuo-Sheng Reactor ...

  5. Fabrication and research of high purity germanium detectors with abrupt and thin diffusion layer

    International Nuclear Information System (INIS)

    Rodriguez Cabal, A. E.; Diaz Garcia, A.

    1997-01-01

    A different high purity germanium detector's fabrication method is described. A very thin diffusion film with an abrupt change of the type of conductivity is obtained. The fine diffusion layer thickness makes possibly their utilization in experimental systems in which all the data are elaborated directly on the computer. (author) [es

  6. Calibration of Single High Purity Germanium Detector for Whole Body Counter

    International Nuclear Information System (INIS)

    Taha, T.M.; Morsi, T.M.

    2009-01-01

    A new Accuscan II single germanium detector for whole body counter was installed in NRC (Egypt). The current paper concerned on calibration of single high purity germanium detector for whole body counter. Physical parameters affecting on performance of whole body counter such as linearity, minimum detectable activity and source detector distance, SDD were investigated. Counting efficiencies for the detector have been investigated in rear wall, fixed diagnostic position in air. Counting efficiencies for organ compartments such as thyroid, lung, upper and lower gastrointestinal tract have been investigated using transfer phantom in fixed diagnostic and screening positions respectively. The organ compartment efficiencies in screening geometry were higher than that value of diagnostic geometry by a factor of three. The committed dose equivalents of I-131 in thyroid were ranged from 0.073 ± 0.004 to 1.73±0.09 mSv and in lung was 0.02±0.001 mSv

  7. Bibliographical study on the high-purity germanium radiation detectors used in gamma and X spectrometry

    International Nuclear Information System (INIS)

    Bornand, Bernard; Friant, Alain

    1979-03-01

    The germanium or silicon lithium-drifted detectors, Ge(Li) or Si(Li), and high-purity germanium detectors, HP Ge (impurity concentration approximately 10 10 cm -3 ), are the most commonly used at the present time as gamma and X-ray spectrometers. The HP Ge detectors for which room temperature storage is the main characteristic can be obtained with a large volume and a thin window, and are used as the Ge(Li) in γ ray spectrometry or the Si(Li) in X-ray spectrometry. This publication reviews issues from 1974 to 1978 on the state of the art and applications of the HP Ge semiconductor detectors. 101 bibliographical notices with French summaries are presented. An index for authors, documents and periodicals, and subjects is included [fr

  8. Perfomance of a high purity germanium multi-detector telescope for long range particles

    International Nuclear Information System (INIS)

    Riepe, G.; Protic, D.; Suekoesd, C.; Didelez, J.P.; Frascaria, N.; Gerlic, E.; Hourani, E.; Morlet, M.

    1980-01-01

    A telescope of stacked high purity germanium detectors designed for long range charged particles was tested using medium energy protons. Particle identification and the rejection of the low energy tail could be accomplished on-line allowing the measurement of complex spectra. The efficiency of the detector stack for protons was measured up to 156 MeV incoming energy. The various factors affecting the energy resolution are discussed and their estimated contributions are compared with the experimental results

  9. Charge collection performance of a segmented planar high-purity germanium detector

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, R.J. [Department of Physics, The University of Liverpool, Oliver Lodge Laboratory, Liverpool Merseyside L69 7ZE (United Kingdom)], E-mail: R.Cooper@liverpool.ac.uk; Boston, A.J.; Boston, H.C.; Cresswell, J.R.; Grint, A.N.; Harkness, L.J.; Nolan, P.J.; Oxley, D.C.; Scraggs, D.P. [Department of Physics, The University of Liverpool, Oliver Lodge Laboratory, Liverpool Merseyside L69 7ZE (United Kingdom); Lazarus, I.; Simpson, J. [STFC Daresbury Laboratory, Warrington, Cheshire WA4 4AD (United Kingdom); Dobson, J. [Rosemere Cancer Centre, Royal Preston Hospital, Preston PR2 9HT (United Kingdom)

    2008-10-01

    High-precision scans of a segmented planar high-purity germanium (HPGe) detector have been performed with a range of finely collimated gamma ray beams allowing the response as a function of gamma ray interaction position to be quantified. This has allowed the development of parametric pulse shape analysis (PSA) techniques and algorithms for the correction of imperfections in performance. In this paper we report on the performance of this detector, designed for use in a positron emission tomography (PET) development system.

  10. On the timing properties of germanium detectors: The centroid diagrams of prompt photopeaks and Compton events

    International Nuclear Information System (INIS)

    Penev, I.; Andrejtscheff, W.; Protochristov, Ch.; Zhelev, Zh.

    1987-01-01

    In the applications of the generalized centroid shift method with germanium detectors, the energy dependence of the time centroids of prompt photopeaks (zero-time line) and of Compton background events reveal a peculiar behavior crossing each other at about 100 keV. The effect is plausibly explained as associated with the ratio of γ-quanta causing the photoeffect and Compton scattering, respectively, at the boundaries of the detector. (orig.)

  11. Development of segmented germanium detectors for neutrinoless double beta decay experiments

    International Nuclear Information System (INIS)

    Liu, Jing

    2009-01-01

    The results from neutrino oscillation experiments indicate that at least two neutrinos have mass. However, the value of the masses and whether neutrinos and anti-neutrinos are identical, i.e., Majorana particles, remain unknown. Neutrinoless double beta decay experiments can help to improve our understanding in both cases and are the only method currently possible to tackle the second question. The GERmanium Detector Array (GERDA) experiment, which will search for the neutrinoless double beta decay of 76 Ge, is currently under construction in Hall A of the INFN Gran Sasso National Laboratory (LNGS), Italy. In order to achieve an extremely low background level, segmented germanium detectors are considered to be operated directly in liquid argon which serves simultaneously as cooling and shielding medium. Several test cryostats were built at the Max-Planck-Institut fuer Physik in Muenchen to operate segmented germanium detectors both in vacuum and submerged in cryogenic liquid. The performance and the background discrimination power of segmented germanium detectors were studied in detail. It was proven for the first time that segmented germanium detectors can be operated stably over long periods submerged in a cryogenic liquid. It was confirmed that the segmentation scheme employed does well in the identification of photon induced background and demonstrated for the first time that also neutron interactions can be identified. The C++ Monte Carlo framework, MaGe (Majorana-GERDA), is a joint development of the Majorana and GERDA collaborations. It is based on GEANT4, but tailored especially to simulate the response of ultra-low background detectors to ionizing radiation. The predictions of the simulation were veri ed to be accurate for a wide range of conditions. Some shortcomings were found and corrected. Pulse shape analysis is complementary to segmentation in identifying background events. Its efficiency can only be correctly determined using reliable pulse shape

  12. Development of segmented germanium detectors for neutrinoless double beta decay experiments

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jing

    2009-06-09

    The results from neutrino oscillation experiments indicate that at least two neutrinos have mass. However, the value of the masses and whether neutrinos and anti-neutrinos are identical, i.e., Majorana particles, remain unknown. Neutrinoless double beta decay experiments can help to improve our understanding in both cases and are the only method currently possible to tackle the second question. The GERmanium Detector Array (GERDA) experiment, which will search for the neutrinoless double beta decay of {sup 76}Ge, is currently under construction in Hall A of the INFN Gran Sasso National Laboratory (LNGS), Italy. In order to achieve an extremely low background level, segmented germanium detectors are considered to be operated directly in liquid argon which serves simultaneously as cooling and shielding medium. Several test cryostats were built at the Max-Planck-Institut fuer Physik in Muenchen to operate segmented germanium detectors both in vacuum and submerged in cryogenic liquid. The performance and the background discrimination power of segmented germanium detectors were studied in detail. It was proven for the first time that segmented germanium detectors can be operated stably over long periods submerged in a cryogenic liquid. It was confirmed that the segmentation scheme employed does well in the identification of photon induced background and demonstrated for the first time that also neutron interactions can be identified. The C++ Monte Carlo framework, MaGe (Majorana-GERDA), is a joint development of the Majorana and GERDA collaborations. It is based on GEANT4, but tailored especially to simulate the response of ultra-low background detectors to ionizing radiation. The predictions of the simulation were veri ed to be accurate for a wide range of conditions. Some shortcomings were found and corrected. Pulse shape analysis is complementary to segmentation in identifying background events. Its efficiency can only be correctly determined using reliable pulse

  13. Germanium nitride and oxynitride films for surface passivation of Ge radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Maggioni, G., E-mail: maggioni@lnl.infn.it [Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Viale dell’Universita’2, I-35020 Legnaro, Padova (Italy); Carturan, S. [Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Viale dell’Universita’2, I-35020 Legnaro, Padova (Italy); Fiorese, L. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Viale dell’Universita’2, I-35020 Legnaro, Padova (Italy); Dipartimento di Ingegneria dei Materiali e delle Tecnologie Industriali, Università di Trento, Via Mesiano 77, I-38050 Povo, Trento (Italy); Pinto, N.; Caproli, F. [Scuola di Scienze e Tecnologie, Sezione di Fisica, Università di Camerino, Via Madonna delle Carceri 9, Camerino (Italy); INFN, Sezione di Perugia, Perugia (Italy); Napoli, D.R. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Viale dell’Universita’2, I-35020 Legnaro, Padova (Italy); Giarola, M.; Mariotto, G. [Dipartimento di Informatica—Università di Verona, Strada le Grazie 15, I-37134 Verona (Italy)

    2017-01-30

    Highlights: • A surface passivation method for HPGe radiation detectors is proposed. • Highly insulating GeNx- and GeOxNy-based layers are deposited at room temperature. • Deposition parameters affect composition and electrical properties of the layers. • The improved performance of a GeNx-coated HPGe diode is assessed. - Abstract: This work reports a detailed investigation of the properties of germanium nitride and oxynitride films to be applied as passivation layers to Ge radiation detectors. All the samples were deposited at room temperature by reactive RF magnetron sputtering. A strong correlation was found between the deposition parameters, such as deposition rate, substrate bias and atmosphere composition, and the oxygen and nitrogen content in the film matrix. We found that all the films were very poorly crystallized, consisting of very small Ge nitride and oxynitride nanocrystallites, and electrically insulating, with the resistivity changing from three to six orders of magnitude as a function of temperature. A preliminary test of these films as passivation layers was successfully performed by depositing a germanium nitride film on the intrinsic surface of a high-purity germanium (HPGe) diode and measuring the improved performance, in terms of leakage current, with respect to a reference passivated diode. All these interesting results allow us to envisage the application of this coating technology to the surface passivation of germanium-based radiation detectors.

  14. High-precision efficiency calibration of a high-purity co-axial germanium detector

    Energy Technology Data Exchange (ETDEWEB)

    Blank, B., E-mail: blank@cenbg.in2p3.fr [Centre d' Etudes Nucléaires de Bordeaux Gradignan, UMR 5797, CNRS/IN2P3, Université de Bordeaux, Chemin du Solarium, BP 120, 33175 Gradignan Cedex (France); Souin, J.; Ascher, P.; Audirac, L.; Canchel, G.; Gerbaux, M.; Grévy, S.; Giovinazzo, J.; Guérin, H.; Nieto, T. Kurtukian; Matea, I. [Centre d' Etudes Nucléaires de Bordeaux Gradignan, UMR 5797, CNRS/IN2P3, Université de Bordeaux, Chemin du Solarium, BP 120, 33175 Gradignan Cedex (France); Bouzomita, H.; Delahaye, P.; Grinyer, G.F.; Thomas, J.C. [Grand Accélérateur National d' Ions Lourds, CEA/DSM, CNRS/IN2P3, Bvd Henri Becquerel, BP 55027, F-14076 CAEN Cedex 5 (France)

    2015-03-11

    A high-purity co-axial germanium detector has been calibrated in efficiency to a precision of about 0.15% over a wide energy range. High-precision scans of the detector crystal and γ-ray source measurements have been compared to Monte-Carlo simulations to adjust the dimensions of a detector model. For this purpose, standard calibration sources and short-lived online sources have been used. The resulting efficiency calibration reaches the precision needed e.g. for branching ratio measurements of super-allowed β decays for tests of the weak-interaction standard model.

  15. Comparison of Response Characteristics of High-Purity Germanium Detectors using Analog Versus Digital Processing

    International Nuclear Information System (INIS)

    Luke, S J; Raschke, K

    2004-01-01

    In this article we will discuss some of the results of the response characteristics of High Purity germanium detectors using analog versus digital processing of the signals that are outputted from the detector. The discussion will focus on whether or not there is a significant difference in the response of the detector with digital electronics that it limits the ability of the detection system to get reasonable gamma ray spectrometric results. Particularly, whether or not the performance of the analysis code Pu600 is compromised

  16. Dual germanium detector system for the routine assay of low level transuranics in soil

    International Nuclear Information System (INIS)

    Crowell, J.M.

    1980-01-01

    As an outgrowth of previous on soil radioassay, we have developed an automated assay system for determining the transuranic radionuclide content of soils, with particular interest in Pu. The system utilizes two commercial planar intrinsic germanium detectors in opposition. The large area of the detectors (2100 mm 2 ) and the thinness of the detector crystals (7 mm) permit sensitive analysis of the L x ray emission region of the transuranics (13 to 21 keV). With counting times of 5 hours, we obtain detection limits of 241 Am

  17. CDEX-1 1 kg point-contact germanium detector for low mass dark matter searches

    International Nuclear Information System (INIS)

    Kang Kejun; Yue Qian; Wu Yucheng

    2013-01-01

    The CDEX collaboration has been established for direct detection of light dark matter particles, using ultra-low energy threshold point-contact p-type germanium detectors, in China JinPing underground Laboratory (CJPL). The first 1 kg point-contact germanium detector with a sub-keV energy threshold has been tested in a passive shielding system located in CJPL. The outputs from both the point-contact P + electrode and the outside N + electrode make it possible to scan the lower energy range of less than 1 keV and at the same time to detect the higher energy range up to 3 MeV. The outputs from both P + and N + electrode may also provide a more powerful method for signal discrimination for dark matter experiment. Some key parameters, including energy resolution, dead time, decay times of internal X-rays, and system stability, have been tested and measured. The results show that the 1 kg point-contact germanium detector, together with its shielding system and electronics, can run smoothly with good performances. This detector system will be deployed for dark matter search experiments. (authors)

  18. The GALATEA test facility and a first study of α-induced surface events in a germanium detector

    Energy Technology Data Exchange (ETDEWEB)

    Irlbeck, Sabine

    2014-01-30

    Germanium detectors are a choice technology in fundamental research. They are suitable for the search for rare events due to their high sensitivity and excellent energy resolution. As an example, the GERDA (GERmanium Detector Array) experiment searching for neutrinoless double beta decay is described. The observation of this decay would resolve the fundamental question whether the neutrino is its own antiparticle. Especially adapted detector technologies and low background rates needed to detect very rare events such as neutrinoless double beta decays are discussed. The identification of backgrounds originating from the interaction of radiation, especially α-particles, is a focus of this thesis. Low background experiments face problems from α-particles due to unavoidable surface contaminations of the germanium detectors. The segmentation of detectors is used to obtain information about the special characteristics of selected events. The high precision test stand GALATEA was especially designed for surface scans of germanium detectors. As part of this work, GALATEA was completed and commissioned. The final commissioning required major upgrades of the original design which are described in detail. Collimator studies with two commercial germanium detectors are presented. Different collimation levels for a β-source were investigated and crystal axis effects were examined. The first scan with an α-source of the passivated end-plate of a special 19-fold segmented prototype detector mounted in GALATEA is described. The α-induced surface events were studied and characterized. Crosstalk and mirror pulses seen in the segments of the germanium detector were analyzed. The detector studies presented in this thesis will help to further improve the design of germanium detectors for low background experiments.

  19. The GALATEA test facility and a first study of α-induced surface events in a germanium detector

    International Nuclear Information System (INIS)

    Irlbeck, Sabine

    2014-01-01

    Germanium detectors are a choice technology in fundamental research. They are suitable for the search for rare events due to their high sensitivity and excellent energy resolution. As an example, the GERDA (GERmanium Detector Array) experiment searching for neutrinoless double beta decay is described. The observation of this decay would resolve the fundamental question whether the neutrino is its own antiparticle. Especially adapted detector technologies and low background rates needed to detect very rare events such as neutrinoless double beta decays are discussed. The identification of backgrounds originating from the interaction of radiation, especially α-particles, is a focus of this thesis. Low background experiments face problems from α-particles due to unavoidable surface contaminations of the germanium detectors. The segmentation of detectors is used to obtain information about the special characteristics of selected events. The high precision test stand GALATEA was especially designed for surface scans of germanium detectors. As part of this work, GALATEA was completed and commissioned. The final commissioning required major upgrades of the original design which are described in detail. Collimator studies with two commercial germanium detectors are presented. Different collimation levels for a β-source were investigated and crystal axis effects were examined. The first scan with an α-source of the passivated end-plate of a special 19-fold segmented prototype detector mounted in GALATEA is described. The α-induced surface events were studied and characterized. Crosstalk and mirror pulses seen in the segments of the germanium detector were analyzed. The detector studies presented in this thesis will help to further improve the design of germanium detectors for low background experiments.

  20. Germanium cryogenic detectors: Alpha surface events rejection capabilities

    International Nuclear Information System (INIS)

    Fiorucci, S.; Broniatowski, A.; Chardin, G.; Censier, B.; Lesquen, A. de; Deschamps, H.; Fesquet, M.; Jin, Y.

    2006-01-01

    Alpha surface events and multiple compton gamma interactions are the two major background components in Ge detectors for double-beta decay investigations. Two different methods have been studied to identify such type of events, using cryogenic Ge detectors developed primarily for dark matter search: (i) combined heat and ionization measurements, and (ii) pulse-shape analysis of the charge collection signals. Both methods show strong separation between electron recoil events and surface alphas. Cryogenic heat-ionization detectors therefore appear able to reject virtually all surface alpha interactions

  1. A high resolution germanium detector array for hypernuclear studies at PANDA

    Energy Technology Data Exchange (ETDEWEB)

    Bleser, Sebastian; Sanchez Lorente, Alicia; Steinen, Marcell [Helmholtz-Institut Mainz (Germany); Gerl, Juergen; Kojouharov, Ivan [GSI, Darmstadt (Germany); Iazzi, Felice [Politecnico, Torino, Turin (Italy); INFN, Torino, Turin (Italy); Pochodzalla, Josef; Rittgen, Kai; Sahin, Cihan [Institute for Nuclear Physics, JGU Mainz (Germany); Collaboration: PANDA-Collaboration

    2013-07-01

    The PANDA experiment, planned at the FAIR facility in Darmstadt, aims at the high resolution γ-spectroscopy of double Λ hypernuclei. For this purpose a devoted detector setup is required, consisting of a primary nuclear target, an active secondary target and a germanium detector array for the γ-spectroscopy. Due to the limited space within the PANDA detector a compact design is required. In particular the conventional LN{sub 2} cooling system must be replaced by an electro-mechanical device and a new arrangement of the crystals is needed. This poster shows the ongoing development of the germanium detectors. Test measurements of a single crystal prototype with an improved cooling concept are shown. Thermal simulations for a triple crystal detector are presented. Aditionally studies of the optimization of the detector arrangement inside the PANDA barrel spectrometer are shown. Finally the status on digital pulse shape analysis is presented which will be necessary to deal with high counting rates and to recover the high original energy resolution in case of neutron damage.

  2. Ultra low energy-ultra low background high purity germanium detectors for studies on dark matter

    International Nuclear Information System (INIS)

    Soma, A.K.; Singh, V.; Singh, L.; Singh, M.K.; Wong, H.T.

    2009-01-01

    Weakly Interacting Massive Particles (WIMP) are the leading DM candidates. Super symmetric particles (SUSY) are one of the leading WIMP candidates. To probe this least explored region Taiwan EXperiments On NeutrinO collaboration is pursuing research and development program by using High Purity Germanium detectors (HPGe). These detectors offer a matured technology to scale up the detectors and achieve sub-keV level threshold i.e. few hundreds of eV, economically. The various detectors developed by the collaboration is shown in the below figure. The current goal of the collaboration is to develop detectors of kg-scale target mass, ∼100 eV threshold and low-background specification for the studies on WIMPs, μ v and neutrino - nucleus coherent scattering

  3. Gamma-ray escape peak characteristics of radiation-damaged reverse-electrode germanium coaxial detectors

    International Nuclear Information System (INIS)

    Pehl, R.H.; Hull, E.L.; Madden, N.W.; Xing Jingshu; Friesel, D.L.

    1996-01-01

    A comparison of the characteristics of full-energy gamma-ray peaks and their corresponding escape peaks when high energy photons interact in radiation damaged reverse-electrode (n-type) germanium coaxial detectors is presented. Coaxial detector geometry is the dominant factor, causing charge collection to be dramatically better for interactions occurring near the outer periphery of the detector as well as increasing of the probability of escape events occurring in this region. It follows that the resolution of escape peaks is better than that of ordinary gamma-ray peaks. This is experimentally verified. A nearly identical but undamaged detector exhibited significant Doppler broadening of single escape peaks. Because double escape events preferentially occur at outer radii, energy shifts of double escape reflect extremely small amounts of charge trapping in undamaged detectors. (orig.)

  4. CERN manufactured hybrid photon detectors

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    These hybrid photon detectors (HPDs) produce an electric signal from a single photon. An electron is liberated from a photocathode and accelerated to a silicon pixel array allowing the location of the photon on the cathode to be recorded. The electronics and optics for these devices have been developed in close collaboration with industry. HPDs have potential for further use in astrophysics and medical imaging.

  5. Bulk and surface event identification in p-type germanium detectors

    Science.gov (United States)

    Yang, L. T.; Li, H. B.; Wong, H. T.; Agartioglu, M.; Chen, J. H.; Jia, L. P.; Jiang, H.; Li, J.; Lin, F. K.; Lin, S. T.; Liu, S. K.; Ma, J. L.; Sevda, B.; Sharma, V.; Singh, L.; Singh, M. K.; Singh, M. K.; Soma, A. K.; Sonay, A.; Yang, S. W.; Wang, L.; Wang, Q.; Yue, Q.; Zhao, W.

    2018-04-01

    The p-type point-contact germanium detectors have been adopted for light dark matter WIMP searches and the studies of low energy neutrino physics. These detectors exhibit anomalous behavior to events located at the surface layer. The previous spectral shape method to identify these surface events from the bulk signals relies on spectral shape assumptions and the use of external calibration sources. We report an improved method in separating them by taking the ratios among different categories of in situ event samples as calibration sources. Data from CDEX-1 and TEXONO experiments are re-examined using the ratio method. Results are shown to be consistent with the spectral shape method.

  6. In-beam measurement of the position resolution of a highly segmented coaxial germanium detector

    International Nuclear Information System (INIS)

    Descovich, M.; Lee, I.Y.; Fallon, P.; Cromaz, M.; Macchiavelli, A.O.; Radford, D.C.; Vetter, K.; Clark, R.M.; Deleplanque, M.A.; Stephens, F.S.; Ward, D.

    2005-01-01

    The position resolution of a highly segmented coaxial germanium detector was determined by analyzing the 2055keV γ-ray transition of Zr90 excited in a fusion-evaporation reaction. The high velocity of the Zr90 nuclei imparted large Doppler shifts. Digital analysis of the detector signals recovered the energy and position of individual γ-ray interactions. The location of the first interaction in the crystal was used to correct the Doppler energy shift. Comparison of the measured energy resolution with simulations implied a position resolution (root mean square) of 2mm in three-dimensions

  7. Measuring Pu in a glove box using portable NaI and germanium detectors

    International Nuclear Information System (INIS)

    Hankins, D.E.

    1984-01-01

    A NaI crystal or germanium detector inside a portable lead shield can determine the amount of plutonium in a glove box. The number of counts required are defined and the locations outside the box where the detector needs to be positioned are given. The calculated accuracy for measuring the Pu when these locations are used is within +/-30% for most glove boxes. Other factors that may affect this accuracy, such as γ-ray absorption by glove-box materials, self-absorption by Pu, absorption by equipment in the glove box, and the limits of the counting equipment are also discussed

  8. Diffusion of interstitial oxygen in silicon and germanium: a hybrid functional study

    International Nuclear Information System (INIS)

    Colleoni, Davide; Pasquarello, Alfredo

    2016-01-01

    The minimum-energy paths for the diffusion of an interstitial O atom in silicon and germanium are studied through the nudged-elastic-band method and hybrid functional calculations. The reconsideration of the diffusion of O in silicon primarily serves the purpose of validating the procedure for studying the O diffusion in germanium. Our calculations show that the minimum energy path goes through an asymmetric transition state in both silicon and germanium. The stability of these transition states is found to be enhanced by the generation of unpaired electrons in the highest occupied single-particle states. Calculated energy barriers are 2.54 and 2.14 eV for Si and Ge, in very good agreement with corresponding experimental values of 2.53 and 2.08 eV, respectively. (paper)

  9. A novel iterative energy calibration method for composite germanium detectors

    International Nuclear Information System (INIS)

    Pattabiraman, N.S.; Chintalapudi, S.N.; Ghugre, S.S.

    2004-01-01

    An automatic method for energy calibration of the observed experimental spectrum has been developed. The method presented is based on an iterative algorithm and presents an efficient way to perform energy calibrations after establishing the weights of the calibration data. An application of this novel technique for data acquired using composite detectors in an in-beam γ-ray spectroscopy experiment is presented

  10. A novel iterative energy calibration method for composite germanium detectors

    Energy Technology Data Exchange (ETDEWEB)

    Pattabiraman, N.S.; Chintalapudi, S.N.; Ghugre, S.S. E-mail: ssg@alpha.iuc.res.in

    2004-07-01

    An automatic method for energy calibration of the observed experimental spectrum has been developed. The method presented is based on an iterative algorithm and presents an efficient way to perform energy calibrations after establishing the weights of the calibration data. An application of this novel technique for data acquired using composite detectors in an in-beam {gamma}-ray spectroscopy experiment is presented.

  11. Methods to improve and understand the sensitivity of high purity germanium detectors for searches of rare events

    International Nuclear Information System (INIS)

    Volynets, Oleksandr

    2012-01-01

    Observation of neutrinoless double beta-decay could answer fundamental questions on the nature of neutrinos. High purity germanium detectors are well suited to search for this rare process in germanium. Successful operation of such experiments requires a good understanding of the detectors and the sources of background. Possible background sources not considered before in the presently running GERDA high purity germanium detector experiment were studied. Pulse shape analysis using artificial neural networks was used to distinguish between signal-like and background-like events. Pulse shape simulation was used to investigate systematic effects influencing the efficiency of the method. Possibilities to localize the origin of unwanted radiation using Compton back-tracking in a granular detector system were examined. Systematic effects in high purity germanium detectors influencing their performance have been further investigated using segmented detectors. The behavior of the detector response at different operational temperatures was studied. The anisotropy effects due to the crystallographic structure of germanium were facilitated in a novel way to determine the orientation of the crystallographic axes.

  12. Methods to improve and understand the sensitivity of high purity germanium detectors for searches of rare events

    Energy Technology Data Exchange (ETDEWEB)

    Volynets, Oleksandr

    2012-07-27

    Observation of neutrinoless double beta-decay could answer fundamental questions on the nature of neutrinos. High purity germanium detectors are well suited to search for this rare process in germanium. Successful operation of such experiments requires a good understanding of the detectors and the sources of background. Possible background sources not considered before in the presently running GERDA high purity germanium detector experiment were studied. Pulse shape analysis using artificial neural networks was used to distinguish between signal-like and background-like events. Pulse shape simulation was used to investigate systematic effects influencing the efficiency of the method. Possibilities to localize the origin of unwanted radiation using Compton back-tracking in a granular detector system were examined. Systematic effects in high purity germanium detectors influencing their performance have been further investigated using segmented detectors. The behavior of the detector response at different operational temperatures was studied. The anisotropy effects due to the crystallographic structure of germanium were facilitated in a novel way to determine the orientation of the crystallographic axes.

  13. Experimental test of the background rejection, through imaging capability, of a highly segmented AGATA germanium detector

    International Nuclear Information System (INIS)

    Doncel, M.; Recchia, F.; Quintana, B.; Gadea, A.; Farnea, E.

    2010-01-01

    The development of highly segmented germanium detectors as well as the algorithms to identify the position of the interaction within the crystal opens the possibility to locate the γ-ray source using Compton imaging algorithms. While the Compton-suppression shield, coupled to the germanium detector in conventional arrays, works also as an active filter against the γ rays originated outside the target, the new generation of position sensitive γ-ray detector arrays has to fully rely on tracking capabilities for this purpose. In specific experimental conditions, as the ones foreseen at radioactive beam facilities, the ability to discriminate background radiation improves the sensitivity of the gamma spectrometer. In this work we present the results of a measurement performed at the Laboratori Nazionali di Legnaro (LNL) aiming the evaluation of the AGATA detector capabilities to discriminate the origin of the γ rays on an event-by-event basis. It will be shown that, exploiting the Compton scattering formula, it is possible to track back γ rays coming from different positions, assigning them to specific emitting locations. These imaging capabilities are quantified for a single crystal AGATA detector.

  14. A high resolution germanium detector array for hypernuclear studies at PANDA

    Energy Technology Data Exchange (ETDEWEB)

    Bleser, Sebastian; Sanchez Lorente, Alicia; Steinen, Marcell [Helmholtz-Institut Mainz (Germany); Gerl, Juergen; Kojouharova, Jasmina; Kojouharov, Ivan [GSI Darmstadt (Germany); Iazzi, Felice [Politecnico, Torino (Italy); INFN, Torino (Italy); Pochodzalla, Josef; Rittgen, Kai; Sahin, Cihan [Institute for Nuclear Physics, JGU Mainz (Germany)

    2014-07-01

    The PANDA experiment, planned at the FAIR facility in Darmstadt, aims at the high resolution γ-spectroscopy of double Λ hypernuclei. For this purpose a devoted detector setup is required, consisting of a primary nuclear target, an active secondary target and a germanium detector array for the γ-spectroscopy. Due to the limited space within the PANDA detector a compact design is required. In particular the conventional LN{sub 2} cooling system must be replaced by an electro mechanical device and a new arrangement of the crystals is needed. This presentation shows the progress in the development of the germanium detectors. First results of in-beam measurements at COSY with a new electro mechanically cooled single crystal prototype are presented. Digital pulse shape analysis is used to disentangle pile up events due to the high event rate. This analysis technique also allows to recover the high original energy resolution in case of neutron damage. Finally the status of the new triple crystal detector prototype is given.

  15. Characterization of segmented large volume, high purity germanium detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bruyneel, B. [Koeln Univ. (Germany). Inst. fuer Kernphysik

    2006-07-01

    {gamma}-ray tracking in future HPGe arrays like AGATA will rely on pulse shape analysis (PSA) of multiple {gamma}-interactions. For this purpose, a simple and fast procedure was developed which enabled the first full characterization of a segmented large volume HPGe detector. An analytical model for the hole mobility in a Ge crystal lattice was developed to describe the hole drift anisotropy with experimental velocity values along the crystal axis as parameters. The new model is based on the drifted Maxwellian hole distribution in Ge. It is verified by reproducing successfully experimental longitudinal hole anisotropy data. A comparison between electron and hole mobility shows large differences for the longitudinal and tangential velocity anisotropy as a function of the electrical field orientation. Measurements on a 12 fold segmented, n-type, large volume, irregular shaped HPGe detector were performed in order to determine the parameters of anisotropic mobility for electrons and holes as charge carriers created by {gamma}-ray interactions. To characterize the electron mobility the complete outer detector surface was scanned in small steps employing photopeak interactions at 60 keV. A precise measurement of the hole drift anisotropy was performed with 356 keV rays. The drift velocity anisotropy and crystal geometry cause considerable rise time differences in pulse shapes depending on the position of the spatial charge carrier creation. Pulse shapes of direct and transient signals are reproduced by weighting potential calculations with high precision. The measured angular dependence of rise times is caused by the anisotropic mobility, crystal geometry, changing field strength and space charge effects. Preamplified signals were processed employing digital spectroscopy electronics. Response functions, crosstalk contributions and averaging procedures were taken into account implying novel methods due to the segmentation of the Ge-crystal and the digital electronics

  16. Characterization of segmented large volume, high purity germanium detectors

    International Nuclear Information System (INIS)

    Bruyneel, B.

    2006-01-01

    γ-ray tracking in future HPGe arrays like AGATA will rely on pulse shape analysis (PSA) of multiple γ-interactions. For this purpose, a simple and fast procedure was developed which enabled the first full characterization of a segmented large volume HPGe detector. An analytical model for the hole mobility in a Ge crystal lattice was developed to describe the hole drift anisotropy with experimental velocity values along the crystal axis as parameters. The new model is based on the drifted Maxwellian hole distribution in Ge. It is verified by reproducing successfully experimental longitudinal hole anisotropy data. A comparison between electron and hole mobility shows large differences for the longitudinal and tangential velocity anisotropy as a function of the electrical field orientation. Measurements on a 12 fold segmented, n-type, large volume, irregular shaped HPGe detector were performed in order to determine the parameters of anisotropic mobility for electrons and holes as charge carriers created by γ-ray interactions. To characterize the electron mobility the complete outer detector surface was scanned in small steps employing photopeak interactions at 60 keV. A precise measurement of the hole drift anisotropy was performed with 356 keV rays. The drift velocity anisotropy and crystal geometry cause considerable rise time differences in pulse shapes depending on the position of the spatial charge carrier creation. Pulse shapes of direct and transient signals are reproduced by weighting potential calculations with high precision. The measured angular dependence of rise times is caused by the anisotropic mobility, crystal geometry, changing field strength and space charge effects. Preamplified signals were processed employing digital spectroscopy electronics. Response functions, crosstalk contributions and averaging procedures were taken into account implying novel methods due to the segmentation of the Ge-crystal and the digital electronics. The results are

  17. A segmented, enriched N-type germanium detector for neutrinoless double beta-decay experiments

    Science.gov (United States)

    Leviner, L. E.; Aalseth, C. E.; Ahmed, M. W.; Avignone, F. T.; Back, H. O.; Barabash, A. S.; Boswell, M.; De Braeckeleer, L.; Brudanin, V. B.; Chan, Y.-D.; Egorov, V. G.; Elliott, S. R.; Gehman, V. M.; Hossbach, T. W.; Kephart, J. D.; Kidd, M. F.; Konovalov, S. I.; Lesko, K. T.; Li, Jingyi; Mei, D.-M.; Mikhailov, S.; Miley, H.; Radford, D. C.; Reeves, J.; Sandukovsky, V. G.; Umatov, V. I.; Underwood, T. A.; Tornow, W.; Wu, Y. K.; Young, A. R.

    2014-01-01

    We present data characterizing the performance of the first segmented, N-type Ge detector, isotopically enriched to 85% 76Ge. This detector, based on the Ortec PT6×2 design and referred to as SEGA (Segmented, Enriched Germanium Assembly), was developed as a possible prototype for neutrinoless double beta-decay measurements by the MAJORANA collaboration. We present some of the general characteristics (including bias potential, efficiency, leakage current, and integral cross-talk) for this detector in its temporary cryostat. We also present an analysis of the resolution of the detector, and demonstrate that for all but two segments there is at least one channel that reaches the MAJORANA resolution goal below 4 keV FWHM at 2039 keV, and all channels are below 4.5 keV FWHM.

  18. Amorphous Silicon-Germanium Films with Embedded Nanocrystals for Thermal Detectors with Very High Sensitivity

    Directory of Open Access Journals (Sweden)

    Cesar Calleja

    2016-01-01

    Full Text Available We have optimized the deposition conditions of amorphous silicon-germanium films with embedded nanocrystals in a plasma enhanced chemical vapor deposition (PECVD reactor, working at a standard frequency of 13.56 MHz. The objective was to produce films with very large Temperature Coefficient of Resistance (TCR, which is a signature of the sensitivity in thermal detectors (microbolometers. Morphological, electrical, and optical characterization were performed in the films, and we found optimal conditions for obtaining films with very high values of thermal coefficient of resistance (TCR = 7.9% K−1. Our results show that amorphous silicon-germanium films with embedded nanocrystals can be used as thermosensitive films in high performance infrared focal plane arrays (IRFPAs used in commercial thermal cameras.

  19. Characterization of a high-purity germanium detector for small-animal SPECT.

    Science.gov (United States)

    Johnson, Lindsay C; Campbell, Desmond L; Hull, Ethan L; Peterson, Todd E

    2011-09-21

    We present an initial evaluation of a mechanically cooled, high-purity germanium double-sided strip detector as a potential gamma camera for small-animal SPECT. It is 90 mm in diameter and 10 mm thick with two sets of 16 orthogonal strips that have a 4.5 mm width with a 5 mm pitch. We found an energy resolution of 0.96% at 140 keV, an intrinsic efficiency of 43.3% at 122 keV and a FWHM spatial resolution of approximately 1.5 mm. We demonstrated depth-of-interaction estimation capability through comparison of pinhole acquisitions with a point source on and off axes. Finally, a flood-corrected flood image exhibited a strip-level uniformity of less than 1%. This high-purity germanium offers many desirable properties for small-animal SPECT.

  20. Amorphous Silicon-Germanium Films with Embedded Nano crystals for Thermal Detectors with Very High Sensitivity

    International Nuclear Information System (INIS)

    Calleja, C.; Torres, A.; Rosales-Quintero, P.; Moreno, M.

    2016-01-01

    We have optimized the deposition conditions of amorphous silicon-germanium films with embedded nano crystals in a plasma enhanced chemical vapor deposition (PECVD) reactor, working at a standard frequency of 13.56 MHz. The objective was to produce films with very large Temperature Coefficient of Resistance (TCR), which is a signature of the sensitivity in thermal detectors (micro bolometers). Morphological, electrical, and optical characterization were performed in the films, and we found optimal conditions for obtaining films with very high values of thermal coefficient of resistance (TCR = 7.9%K -1 ). Our results show that amorphous silicon-germanium films with embedded nano crystals can be used as thermo sensitive films in high performance infrared focal plane arrays (IRFPAs) used in commercial thermal cameras.

  1. Pulse shape analysis for germanium detectors used in DM searches

    International Nuclear Information System (INIS)

    Sagdeev, I.R.; Drukier, A.K.; Welsh, D.J.; Klimenko, A.A.; Osetrov, S.B.; Smolnikov, A.A.

    1994-01-01

    Progress in Ge detector technology has resulted in ultralow backgrounds of less than 0.3 countskeV -1 kg -1 d -1 at energies between 6 and 9keV and from 12 to 20keV. Between 4 and 6keV it is less than 2 countskeV -1 kg -1 d -1 . Coupled with good energy resolution, 0.4keV FWHM at 10keV, this allows searches for DM particles with m≥qslant8GeV/c 2 .Electromagnetic interference (EMI) and acoustical pick-up are the main sources of background in the best Ge detectors. A PC-based on-line pulse shape analysis system is presented which permits rejection of large fraction of the EMI/acoustical background. The hardware uses a low cost, commercially available digital storage oscilloscope (DSO). The software consists of about 40000 lines of code in Pascal and assembly language. We tested this system using a low radioactive background Ge-system at the Baksan observatory. For low energy events (<100keV) this system permits improvement in the background by about 20-30%. ((orig.))

  2. Consistency check of pulse shape discrimination for broad energy germanium detectors using double beta decay data

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Heng-Ye [Max-Planck-Institut fuer Physik, Muenchen (Germany); Collaboration: GERDA-Collaboration

    2013-07-01

    The Gerda (GERmanium Detector Array) experiment was built to study fundamental neutrino properties via neutrinoless double beta decay (0νββ). 0νββ events are single-site events (SSE) confined to a scale about millimeter. However, most of backgrounds are multi-site events (MSE). Broad Energy Germanium detectors (BEGes) offer the potential merits of improved pulse shape recognition efficiencies of SSE/MSE. They allow us to reach the goal of Phase II with a background index of 10{sup -3} cts/(keV.kg.yr) in the ROI. BEGe detectors with a total target mass of 3.63 kg have been installed to the Gerda setup in the Laboratori Nazionali del Gran Sasso (LNGS) in July 2012 and are collecting data since. A consistency check of the pulse shape discrimination (PSD) efficiencies by comparison of calibration data and 2νββ data will be presented. The PSD power of these detectors is demonstrated.

  3. Astroparticle physics with a customized low-background broad energy Germanium detector

    Energy Technology Data Exchange (ETDEWEB)

    Aalseth, Craig E.; Amman, M.; Avignone, Frank T.; Back, Henning O.; Barabash, Alexander S.; Barbeau, P. S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Bugg, William; Burritt, Tom H.; Busch, Matthew; Capps, Greg L.; Chan, Yuen-Dat; Collar, J. I.; Cooper, R. J.; Creswick, R.; Detwiler, Jason A.; Diaz, J.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, Steven R.; Ely, James H.; Esterline, James H.; Farach, H. A.; Fast, James E.; Fields, N.; Finnerty, P.; Fujikawa, Brian; Fuller, Erin S.; Gehman, Victor M.; Giovanetti, G. K.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Harper, Gregory; Hazama, R.; Henning, Reyco; Hime, Andrew; Hoppe, Eric W.; Hossbach, Todd W.; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, Mary; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; Leviner, L.; Loach, J. C.; Luke, P.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Miley, Harry S.; Miller, M. L.; Mizouni, Leila; Myers, Allan W.; Nomachi, Masaharu; Orrell, John L.; Peterson, David; Phillips, D.; Poon, Alan; Prior, Gersende; Qian, J.; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Rodriguez, Larry; Rykaczewski, Krzysztof P.; Salazar, Harold; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Steele, David; Strain, J.; Swift, Gary; Thomas, K.; Timkin, V.; Tornow, W.; Van Wechel, T. D.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Wilkerson, J. F.; Wolfe, B. A.; Xiang, W.; Yakushev, E.; Yaver, Harold; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C.; Zimmerman, S.

    2011-10-01

    The Majorana Collaboration is building the Majorana Demonstrator, a 60 kg array of high purity germanium detectors housed in an ultra-low background shield at the Sanford Underground Laboratory in Lead, SD. The Majorana Demonstrator will search for neutrinoless double-beta decay of 76Ge while demonstrating the feasibility of a tonne-scale experiment. It may also carry out a dark matter search in the 1-10 GeV/c² mass range. We have found that customized Broad Energy Germanium (BEGe) detectors produced by Canberra have several desirable features for a neutrinoless double-beta decay experiment, including low electronic noise, excellent pulse shape analysis capabilities, and simple fabrication. We have deployed a customized BEGe, the Majorana Low-Background BEGe at Kimballton (MALBEK), in a low-background cryostat and shield at the Kimballton Underground Research Facility in Virginia. This paper will focus on the detector characteristics and measurements that can be performed with such a radiation detector in a low-background environment.

  4. Evaluation of Segmented Amorphous-Contact Planar Germanium Detectors for Heavy-Element Research

    Science.gov (United States)

    Jackson, Emily G.

    The challenge of improving our understanding of the very heaviest nuclei is at the forefront of contemporary low-energy nuclear physics. In the last two decades, "in-beam" spectroscopy experiments have advanced from Z=98 to Z=104, Rutherfordium, allowing insights into the dynamics of the fission barrier, high-order deformations, and pairing correlations. However, new detector technologies are needed to advance to even heavier nuclei. This dissertation is aimed at evaluating one promising new technology; large segmented planar germanium wafers for this area of research. The current frontier in gamma-ray spectroscopy involves large-volume (>9 cm thick) coaxial detectors that are position sensitive and employ gamma-ray "tracking". In contrast, the detectors assessed in this dissertation are relatively thin (~1 cm) segmented planar wafers with amorphous-germanium strip contacts that can tolerate extremely high gamma-ray count rates, and can accommodate hostile neutron fluxes. They may be the only path to heavier "in-beam" spectroscopy with production rates below 1 nanobarn. The resiliency of these detectors against neutron-induced damage is examined. Two detectors were deliberately subjected to a non-uniform neutron fluence leading to considerable degradation of performance. The neutrons were produced using the 7Li(p, n)7Be reaction at the UMass Lowell Van-de-Graaff accelerator with a 3.7-MeV proton beam incident on a natural Li target. The energy of the neutrons emitted at zero degrees was 2.0 MeV, close to the mean energy of the fission neutron spectrum, and each detector was exposed to a fluence >3.6 x109 n/cm2. A 3-D software "trap-corrector" gain-matching algorithm considerably restored the overall performance. Other neutron damage mitigation tactics were explored including over biasing the detector and flooding the detector with a high gamma-ray count rate. Various annealing processes to remove neutron damage were investigated. An array of very large diameter

  5. High-Resolution Gamma-Ray Imaging Measurements Using Externally Segmented Germanium Detectors

    Science.gov (United States)

    Callas, J.; Mahoney, W.; Skelton, R.; Varnell, L.; Wheaton, W.

    1994-01-01

    Fully two-dimensional gamma-ray imaging with simultaneous high-resolution spectroscopy has been demonstrated using an externally segmented germanium sensor. The system employs a single high-purity coaxial detector with its outer electrode segmented into 5 distinct charge collection regions and a lead coded aperture with a uniformly redundant array (URA) pattern. A series of one-dimensional responses was collected around 511 keV while the system was rotated in steps through 180 degrees. A non-negative, linear least-squares algorithm was then employed to reconstruct a 2-dimensional image. Corrections for multiple scattering in the detector, and the finite distance of source and detector are made in the reconstruction process.

  6. Feasibility study for use of a germanium detector in the LOFT gamma-ray densitometer

    International Nuclear Information System (INIS)

    Swierkowski, S.P.

    1976-01-01

    The primary aim of this study is to predict the performance of a gamma-ray densitometer system using computer modeling techniques. The system consists of a collimated 137 Cs source, a pipe containing a variable amount of water absorber, and a shielded and collimated germanium detector system. The gamma-ray energy spectrum (number of photon counts as a function of energy) has been computed for several sources at the detector. The response for combined sourceconfigurations has been obtained by linear superposition. The signal essentially consists of the counts in an energy window centered on the 137 Cs source at 662 keV that originate from this source. The noise is the background counts in the signal energy window that originate from 16 N scatter radiation and direct and shield tank activation gammas. The detector signal has been computed for 0, 50, and 100 percent water in the pipe

  7. Direct measurement of homogeneously distributed radioactive air contamination with germanium detectors

    International Nuclear Information System (INIS)

    Sowa, W.

    1990-01-01

    Air contamination by γ emitting radionuclides was measured with a vertically arranged germanium detector, laterally shielded by a lead ring, and calibration factors and detection limits of a number of fission products determined. The possibility of measuring simultaneously existing air and soil contamination by measurements with and without lead shield is described. The change of detection limit of air contamination is presented for different soil contamination levels by the same radionuclide. Calibration factors are given to determine the dose rate on the ground due to air contamination by different radionuclides. (author)

  8. Determination of surface recombination velocity and bulk lifetime in detector grade silicon and germanium crystals

    International Nuclear Information System (INIS)

    Derhacobian, N.; Fine, P.; Walton, J.T.; Wong, Y.K.; Rossington, C.S.; Luke, P.N.

    1993-10-01

    Utility of a noncontact photoconductive decay (PCD) technique is demonstrated in measuring bulk lifetime, τ B , and surface recombination velocity, S, in detector grade silicon and germanium crystals. We show that the simple analytical equations which relate the observed effective lifetimes in PCD transients to τ B and S have a limited range of applicability. The noncontact PCD technique is used to determine the effect of several surface treatments on the observed effective lifetimes in Si and Ge. A degradation of the effective lifetime in Si is reported as result of the growth of a thin layer of native oxide at room temperature under atmospheric conditions

  9. Evaluations of the commercial spectrometer systems for safeguards applications using the germanium detectors

    International Nuclear Information System (INIS)

    Vo, D.T.

    1998-01-01

    Safeguards applications require the best spectrometer systems with excellent resolution, stability, and throughput. Instruments must perform well in all the situations and environments. Data communication to the computer should be convenient, fast, and reliable. The software should have all the necessary tools and be ease to use. Portable systems should be small in size, lightweight, and have a long battery life. Nine commercially available spectrometer systems are tested with both the planar and coaxial germanium detectors. Considering the performance of the Digital Signal Processors (DSP), digital-based spectroscopy may be the future of gamma-ray spectroscopy

  10. CDMS Detector Fabrication Improvements and Low Energy Nuclear Recoil Measurements in Germanium

    Energy Technology Data Exchange (ETDEWEB)

    Jastram, Andrew [Texas A & M Univ., College Station, TX (United States)

    2015-12-01

    As the CDMS (Cryogenic Dark Matter Search) experiment is scaled up to tackle new dark matter parameter spaces (lower masses and cross-sections), detector production efficiency and repeatability becomes ever more important. A dedicated facility has been commissioned for SuperCDMS detector fabrication at Texas A&M University (TAMU). The fabrication process has been carefully tuned using this facility and its equipment. Production of successfully tested detectors has been demonstrated. Significant improvements in detector performance have been made using new fabrication methods, equipment, and tuning of process parameters. This work has demonstrated the capability for production of next generation CDMS SNOLAB detectors. Additionally, as the dark matter parameter space is probed further, careful calibrations of detector response to nuclear recoil interactions must be performed in order to extract useful information (in relation to dark matter particle characterzations) from experimental results. A neutron beam of tunable energy is used in conjunction with a commercial radiation detector to characterize ionization energy losses in germanium during nuclear recoil events. Data indicates agreement with values predicted by the Lindhard equation, providing a best-t k-value of 0.146.

  11. Program LEP to addition of gamma spectra from germanium detectors; Programa LEPS para suma de espectros gammas de detectores de germanio

    Energy Technology Data Exchange (ETDEWEB)

    Romero, L

    1986-07-01

    The LEP program, written in FORTRAN IV, performs the addition of two spectra, collected with different detectors, from the same sample. This application, adds the two gamma spectra obtained from two opposite LEPS Germanium Detectors (Low Energy Photon Spectrometer), correcting the differences (channel/energy) between both two spectra, and fitting them before adding. The total-spectrum is recorded at the computer memory as a single spectrum. The necessary equipment, to run this program is: - Two opposite germanium detectors, with their associate electronics. - Multichannel analyzer (2048 memory channel minimum) - Computer on-line interfacing to multichannel analyzer. (Author) 4 refs.

  12. Surface passivation of high-purity germanium gamma-ray detector

    International Nuclear Information System (INIS)

    Alexiev, D.; Butcher, K.S.A.; Edmondson, M.; Lawson, E.M.

    1993-01-01

    The experimental work consists of two parts. The first involves fabrication of hyper-pure germanium gamma ray detectors using standard surface treatment, chemical etchings and containment in a suitable cryostat. Then, after cooling the detectors to 77 K, γ-ray emissions from radioisotopes are resolved, resolution, depletion depth, V R versus I R characteristics and /N A -N D / of the germanium are measured. The second part of the work involves investigation of surface states in an effort to achieve long-term stability of operating characteristics. Several methods are used: plasma hydrogenation, a-Si and a-Ge pinch-off effect and simple oxidation. A-Ge and a-Si thicknesses were measured using Rutherford backscattering techniques; surface states were measured with deep level transient spectroscopy and diode reverse current versus reverse voltage plots. Some scanning electron microscope measurements were used in determining major film contaminants during backscattering of a-Si and a-Ge films. Surface passivation studies revealed unexpected hole trapping defects generated when a-Ge:H film is applied. The a-Si:H films were found to be mechanically strong, no defect traps were found and preliminary results suggest that such films will be good passivants. 14 refs., 2 tabs., 7 figs., 13 ills

  13. An Experimental Study of the Accuracy of Compensation in Lithium Drifted Germanium Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lauber, A; Malmsten, B

    1969-10-15

    The nature and magnitude of the space charge existing in the compensated layer of lithium drifted germanium detectors has been studied as a function of drifted depth and of the electric field applied during drift. Experimental values were obtained from the dependence of detector capacitance on applied bias. In most cases there was a linear space charge gradient in the compensated layer. When small electric fields were applied to deep compensated layers, the space charge became constant throughout a large part of the compensated layer. There is some evidence for a strong decrease of mobile carrier recombination lifetime with increasing drifted depth, possibly down to a few microseconds for drifted depths of the order of 7 mm. The experimental results of the investigation are to a large extent in good agreement with theory.

  14. The position response of a large-volume segmented germanium detector

    International Nuclear Information System (INIS)

    Descovich, M.; Nolan, P.J.; Boston, A.J.; Dobson, J.; Gros, S.; Cresswell, J.R.; Simpson, J.; Lazarus, I.; Regan, P.H.; Valiente-Dobon, J.J.; Sellin, P.; Pearson, C.J.

    2005-01-01

    The position response of a large-volume segmented coaxial germanium detector is reported. The detector has 24-fold segmentation on its outer contact. The output from each contact was sampled with fast digital signal processing electronics in order to determine the position of the γ-ray interaction from the signal pulse shape. The interaction position was reconstructed in a polar coordinate system by combining the radial information, contained in the rise-time of the pulse leading edge, with the azimuthal information, obtained from the magnitude of the transient charge signals induced on the neighbouring segments. With this method, a position resolution of 3-7mm is achieved in both the radial and the azimuthal directions

  15. The position response of a large-volume segmented germanium detector

    Energy Technology Data Exchange (ETDEWEB)

    Descovich, M. [Oliver Lodge Laboratory, Physics Department, University of Liverpool, Liverpool L69 7ZE (United Kingdom)]. E-mail: mdescovich@lbl.gov; Nolan, P.J. [Oliver Lodge Laboratory, Physics Department, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Boston, A.J. [Oliver Lodge Laboratory, Physics Department, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Dobson, J. [Oliver Lodge Laboratory, Physics Department, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Gros, S. [Oliver Lodge Laboratory, Physics Department, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Cresswell, J.R. [Oliver Lodge Laboratory, Physics Department, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Simpson, J. [CCLRC Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom); Lazarus, I. [CCLRC Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom); Regan, P.H. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Valiente-Dobon, J.J. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Sellin, P. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Pearson, C.J. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2005-11-21

    The position response of a large-volume segmented coaxial germanium detector is reported. The detector has 24-fold segmentation on its outer contact. The output from each contact was sampled with fast digital signal processing electronics in order to determine the position of the {gamma}-ray interaction from the signal pulse shape. The interaction position was reconstructed in a polar coordinate system by combining the radial information, contained in the rise-time of the pulse leading edge, with the azimuthal information, obtained from the magnitude of the transient charge signals induced on the neighbouring segments. With this method, a position resolution of 3-7mm is achieved in both the radial and the azimuthal directions.

  16. Hybrid anode for semiconductor radiation detectors

    Science.gov (United States)

    Yang, Ge; Bolotnikov, Aleksey E; Camarda, Guiseppe; Cui, Yonggang; Hossain, Anwar; Kim, Ki Hyun; James, Ralph B

    2013-11-19

    The present invention relates to a novel hybrid anode configuration for a radiation detector that effectively reduces the edge effect of surface defects on the internal electric field in compound semiconductor detectors by focusing the internal electric field of the detector and redirecting drifting carriers away from the side surfaces of the semiconductor toward the collection electrode(s).

  17. First 10 kg of naked Germanium detectors in liquid nitrogen installed in the GENIUS-Test-Facility

    International Nuclear Information System (INIS)

    Klapdor-Kleingrothaus, H.V.; Chkvorets, O.; Krivosheina, I.V.; Strecker, H.; Tomei, C.

    2003-01-01

    The first four naked high-purity Germanium detectors were installed successfully in liquid nitrogen in the GENIUS-Test-Facility in the GRAN SASSO Underground Laboratory on May 5, 2003. This is the first time ever that this novel technique aiming at extreme background reduction in search for rare decays is going to be tested underground. First operational parameters are presented

  18. Background intercomparison with escape-suppressed germanium detectors in underground mines

    Energy Technology Data Exchange (ETDEWEB)

    Szuecs, Tamas; Bemmerer, Daniel [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany)

    2014-07-01

    A key requirement for underground nuclear astrophysics experiments is the very low background level in germanium detectors underground. The reference for these purposes is the world's so far only underground accelerator laboratory for nuclear astrophysics, LUNA. LUNA is located deep underground in the Gran Sasso laboratory in Italy, shielded from cosmic rays by 1400 m of rock. The background at LUNA was studied in detail using an escape-suppressed Clover-type HPGe detector. Exactly the same detector was subsequently transported to the Felsenkeller underground laboratory in Dresden, shielded by 45 m of rock, and the background was shown to be only a factor of three higher than at LUNA when comparing the escape-suppressed spectra, with interesting consequences for underground nuclear astrophysics. As the next step of a systematic study of the effects of a combination of active and passive shielding on the cosmic ray induced background, this detector is now being brought to the ''Reiche Zeche'' mine in Freiberg/Sachsen, shielded by 150 m of rock. The data from the Freiberg measurement are shown and discussed.

  19. High Purity Germanium Detector as part of Health Canada's Mobile Nuclear Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Stocki, Trevor J.; Bouchard, Claude; Rollings, John; Boudreau, Marc-Oliver; McCutcheon- Wickham, Rory; Bergman, Lauren [Radiation Protection Bureau, Health Canada, AL6302D, 775 Brookfield Road, Ottawa, K1A 0K9 (Canada)

    2014-07-01

    In the event of a nuclear emergency on Canadian soil, Health Canada has designed and equipped two Mobile Nuclear Labs (MNLs) which can be deployed near a radiological accident site to provide radiological measurement capabilities. These measurements would help public authorities to make informed decisions for radiation protection recommendations. One of the MNLs has been outfitted with a High Purity Germanium (HPGe) detector within a lead castle, which can be used for identification as well as quantification of gamma emitting radioisotopes in contaminated soil, water, and other samples. By spring 2014, Health Canada's second MNL will be equipped with a similar detector to increase sample analysis capacity and also provide redundancy if one of the detectors requires maintenance. The Mobile Nuclear Lab (MNL) with the HPGe detector has been successfully deployed in the field for various exercises. One of these field exercises was a dirty bomb scenario where an unknown radioisotope required identification. A second exercise was an inter-comparison between the measurements of spiked soil and water samples, by two field teams and a certified laboratory. A third exercise was the deployment of the MNL as part of a full scale nuclear exercise simulating an emergency at a Canadian nuclear power plant. The lessons learned from these experiences will be discussed. (authors)

  20. First results of neutrinoless double beta decay search with the GERmanium Detector Array "GERDA"

    Science.gov (United States)

    Janicskó Csáthy, József

    2014-06-01

    The study of neutrinoless double beta decay is the most powerful approach to the fundamental question if the neutrino is a Majorana particle, i.e. its own anti-particle. The observation of the lepton number violating neutrinoless double beta decay would establish the Majorana nature of the neutrino. Until now neutrinoless double beta decay was not observed. The GERmanium Detector Array, GERDA is a double beta decay experiment located at the INFN Gran Sasso National Laboratory, Italy. GERDA operates bare Ge diodes enriched in 76Ge in liquid argon supplemented by a water shield. The exposure accumulated adds up to 21.6 kg· yr with a background level of 1.8 · 10-2 cts/(keV·kg·yr). The results of the Phase I of the experiment are presented and the preparation of the Phase II is briefly discussed.

  1. Characterization system for Germanium detectors dedicated to gamma spectroscopy applied to nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Roccaz, J.; Portella, C.; Saurel, N. [CEA, DAM, VALDUC, F-21120 Is-sur-Tille (France)

    2009-07-01

    CEA-Valduc produces some radioactive waste (mainly alpha emitters). Legislation requires producers to sort their waste by activity and type of isotopes, and to package them in order to forward them to the appropriate reprocessing or storage facility. Our lab LMDE (laboratory for measurements on nuclear wastes and valuation) is in charge of the characterization of the majority of waste produced by CEA-Valduc. Among non-destructive methods to characterize a radioactive object, gamma-spectroscopy is one of the most efficient. We present to this conference the method we use to characterize nuclear waste and the system we developed to characterize our germanium detectors. The goal of this system is to obtain reliable numerical models of our detectors and calculate their efficiency curves. Measurements are necessary to checks models and improve them. These measurements are made on a bench using pinpoint sources ({sup 133}Ba, {sup 152}Eu) from 60 keV to 1500 keV, with distances from 'on contact' to a few meters from the diode and variable angles between the source and the detector axis. We have demonstrated that we are able to obtain efficiency curves

  2. The Influence Of Dead Layer Effect On The Characteristics Of The High Purity Germanium P-Type Detector

    International Nuclear Information System (INIS)

    Ngo Quang Huy

    2011-01-01

    The present work aims at reviewing the studies of the influence of dead layer effect on the characteristics of a high purity germanium (HPGe) p-type detector, obtained by the author and his colleagues in the recent years. The object for study was the HPGe GC1518 detector-based gamma spectrometer of the Center for Nuclear Techniques, Ho Chi Minh City. The studying problems were: The modeling of an HPGe detector-based gamma spectrometer with using the MCNP code; the method of determining the thickness of dead layer by experimental measurements of gamma spectra and the calculations using MCNP code; the influence of material parameters and dead layer on detector efficiency; the increase of dead layer thickness over the operating time of the GC1518 detector; the influence of dead layer thickness increase on the decrease of detector efficiency; the dead layer effect for the gamma spectra measured in the GC1518 detector. (author)

  3. Performance and stability tests of bare high purity germanium detectors in liquid argon for the GERDA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Barnabe Heider, Marik

    2009-05-27

    GERDA will search for neutrinoless double beta decay of {sup 76}Ge by using a novel approach of bare germanium detectors in liquid argon (LAr). Enriched germanium detectors from the previous Heidelberg-Moscow and IGEX experiments have been reprocessed and will be deployed in GERDA Phase-I. At the center of this thesis project is the study of the performance of bare germanium detectors in cryogenic liquids. Identical detector performance as in vacuum cryostats (2.2 keV FWHM at 1.3 MeV) was achieved in cryogenic liquids with a new low-mass detector assembly and contacts. One major result is the discovery of a radiation induced leakage current (LC) increase when operating bare detectors with standard passivation layers in LAr. Charge collection and build-up on the passivation layer were identified as the origin of the LC increase. It was found that diodes without passivation do not exhibit this feature. Three month-long stable operation in LAr at {proportional_to} 5 pA LC under periodic gamma irradiation demonstrated the suitability of the modi ed detector design. Based on these results, all Phase-I detectors were reprocessed without passivation layer and subsequently successfully characterized in LAr in the GERDA underground Detector Laboratory. The mass loss during the reprocessing was {proportional_to}300 g out of 17.9 kg and the exposure above ground {proportional_to} 5 days. This results in a negligible cosmogenic background increase of {proportional_to} 5.10{sup -4} cts/(keV.kg.y) at {sup 76}Ge Q{sub {beta}}{sub {beta}} for {sup 60}Co and {sup 68}Ge. (orig.)

  4. Characterization and performance of germanium detectors with sub-keV sensitivities for neutrino and dark matter experiments

    International Nuclear Information System (INIS)

    Soma, A.K.; Singh, M.K.; Singh, L.; Kumar, G. Kiran; Lin, F.K.; Du, Q.; Jiang, H.; Liu, S.K.; Ma, J.L.; Sharma, V.; Wang, L.; Wu, Y.C.; Yang, L.T.; Zhao, W.; Agartioglu, M.; Asryan, G.; Chang, Y.Y.; Chen, J.H.; Chuang, Y.C.

    2016-01-01

    Germanium ionization detectors with sensitivities as low as 100 eV_e_e (electron-equivalent energy) open new windows for studies on neutrino and dark matter physics. The relevant physics subjects are summarized. The detectors have to measure physics signals whose amplitude is comparable to that of pedestal electronic noise. To fully exploit this new detector technique, various experimental issues including quenching factors, energy reconstruction and calibration, signal triggering and selection as well as evaluation of their associated efficiencies have to be attended. The efforts and results of a research program to address these challenges are presented.

  5. Monte Carlo simulation of the X-ray response of a germanium microstrip detector with energy and position resolution

    CERN Document Server

    Rossi, G; Fajardo, P; Morse, J

    1999-01-01

    We present Monte Carlo computer simulations of the X-ray response of a micro-strip germanium detector over the energy range 30-100 keV. The detector consists of a linear array of lithographically defined 150 mu m wide strips on a high purity monolithic germanium crystal of 6 mm thickness. The simulation code is divided into two parts. We first consider a 10 mu m wide X-ray beam striking the detector surface at normal incidence and compute the interaction processes possible for each photon. Photon scattering and absorption inside the detector crystal are simulated using the EGS4 code with the LSCAT extension for low energies. A history of events is created of the deposited energies which is read by the second part of the code which computes the energy histogram for each detector strip. Appropriate algorithms are introduced to account for lateral charge spreading occurring during charge carrier drift to the detector surface, and Fano and preamplifier electronic noise contributions. Computed spectra for differen...

  6. Efficiency for close geometries and extended sources of a p-type germanium detector with low-energy sensitivity

    International Nuclear Information System (INIS)

    Keyser, R.M.; Twomey, T.R.

    2007-01-01

    Typically, germanium detectors designed to have good sensitivity to low-energy photons and good efficiency at high energies are constructed from n-type crystals with a boron-implanted outer contact. These detectors usually exhibit inferior resolution and peak shape compared to ones made from p-type crystals. To overcome the resolution and peak-shape deficiencies, a new method of construction of a germanium detector element was developed. This has resulted in a gamma-ray detector with high sensitivity to photon energies from 14 keV to 2 MeV, while maintaining good resolution and peak shape over this energy range. Efficiency measurements, done according to the draft IEEE 325-2004 standard, show efficiencies typical of a GMX or n-type detector at low energies. The detectors are of large diameter suitable for counting extended samples such as filter papers. The Gaussian peak shape and good resolution typical of a GEM or p-type are maintained for the high count rates and peak separation needed for activation analysis. (author)

  7. Performance of A Compact Multi-crystal High-purity Germanium Detector Array for Measuring Coincident Gamma-ray Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Howard, Chris [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Daigle, Stephen [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Buckner, Matt [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Erikson, Luke E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Runkle, Robert C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stave, Sean C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Champagne, Art [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Cooper, Andrew [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Downen, Lori [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Glasgow, Brian D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kelly, Keegan [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Sallaska, Anne [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States)

    2015-02-18

    The Multi-sensor Airborne Radiation Survey (MARS) detector is a 14-crystal array of high-purity germanium (HPGe) detectors housed in a single cryostat. The array was used to measure the astrophysical S-factor for the 14N(p,γ)15O* reaction for several transition energies at an effective center of mass energy of 163 keV. Owing to the segmented nature of the MARS detector, the effect of gamma-ray summing was greatly reduced in comparison to past experiments which utilized large, single-crystal detectors. The new S-factor values agree within the uncertainties with the past measurements. Details of the analysis and detector performance will be presented.

  8. Performance of a compact multi-crystal high-purity germanium detector array for measuring coincident gamma-ray emissions

    Energy Technology Data Exchange (ETDEWEB)

    Howard, Chris; Daigle, Stephen; Buckner, Matt [University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Erikson, Luke E.; Runkle, Robert C. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Stave, Sean C., E-mail: Sean.Stave@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Champagne, Arthur E.; Cooper, Andrew; Downen, Lori [University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Glasgow, Brian D. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Kelly, Keegan; Sallaska, Anne [University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States)

    2015-05-21

    The Multi-sensor Airborne Radiation Survey (MARS) detector is a 14-crystal array of high-purity germanium (HPGe) detectors housed in a single cryostat. The array was used to measure the astrophysical S-factor for the {sup 14}N(p,γ){sup 15}O{sup ⁎} reaction for several transition energies at an effective center-of-mass energy of 163 keV. Owing to the granular nature of the MARS detector, the effect of gamma-ray summing was greatly reduced in comparison to past experiments which utilized large, single-crystal detectors. The new S-factor values agree within their uncertainties with the past measurements. Details of the analysis and detector performance are presented.

  9. Improvements in Applied Gamma-Ray Spectrometry with Germanium Semiconductor Detector

    Energy Technology Data Exchange (ETDEWEB)

    Brune, D; Hellstroem, S [AB Atomenergi, Nykoeping (Sweden); Dubois, J [Chalmers University of Technology, Goeteborg (Sweden)

    1965-01-15

    A germanium semi-conductor detector has in the present investigation been used in four cases of applied gamma-ray spectrometry. In one case the weak-activity contribution of Cs{sup 134} in Cs{sup 137} standard sources has been determined. The second case concerns the determination of K{sup 42} in samples of biological origin containing strong Na{sup 24} activities. In the third case the Nb{sup 94} and Nb{sup 95} activities from neutron-irradiated niobium foils used in the dosimetry of high neutron fluxes with long exposure times have been completely resolved and it has been possible to determine the ratio of the two activities with a high degree of accuracy. Finally, a Zr{sup 95} - Nb{sup 95} source has been analysed in a similar way with respect to its radiochemical composition. The resolution obtained also made possible a determination of the branching ratio of the two gamma-transitions in Zr{sup 95} and of the energies of the gamma-transitions of both nuclides.

  10. Measurement of energy transitions for the decay radiations of 75Ge and 69Ge in a high purity germanium detector

    Science.gov (United States)

    Aydın, Güral; Usta, Metin; Oktay, Adem

    2018-06-01

    Photoactivation experiments have a wide range of application areas in nuclear, particle physics, and medical physics such as measuring energy levels and half-lifes of nuclei, experiments for understanding imaging methods in medicine, isotope production for patient treatment, radiation security and transportation, radiation therapy, and astrophysics processes. In this study, some energy transition values of the decay radiations of 75Ge and 69Ge, which are the products of photonuclear reactions (γ, n) with germanium isotopes (75Ge and 69Ge), were measured. The gamma spectrum as a result of atomic transitions were analysed by using a high purity semiconductor germanium detector and the energy transition values which are presented here were compared with the ones which are the best in literature. It was observed that the results presented are in agreement with literature in error range and some results have better precisions.

  11. Execution of a cooperative test by means of 'in-situ-gamma spectrometry' using HP-germanium detectors

    International Nuclear Information System (INIS)

    Steger, F.; Lovranich, E.; Urbanich, E.; Streit, S.

    1995-06-01

    A cooperative test was carried out in Salzburg, Austria, in order to determine the activity of Cs-137 and other radio nuclides from the Tschernobyl fallout 1986 and from tests of nuclear weapons in the 1960s. 24 groups from 9 countries of Europe took part. The measurements were performed by means of gamma spectrometry using HP-germanium detectors. Most of the groups had excellent results. The groups became acquainted with each other. The personal contact makes it possible to get information quickly in case of accidents of nuclear power stations in the neighbourhood of Austria

  12. Rare earth substitutional impurities in germanium: A hybrid density functional theory study

    Science.gov (United States)

    Igumbor, E.; Omotoso, E.; Tunhuma, S. M.; Danga, H. T.; Meyer, W. E.

    2017-10-01

    The Heyd, Scuseria, and Ernzerhof (HSE06) hybrid functional by means of density functional theory has been used to model the electronic and structural properties of rare earth (RE) substitutional impurities in germanium (REGe) . The formation and charge state transition energies for the REGe (RE = Ce, Pr, Er and Eu) were calculated. The energy of formation for the neutral charge state of the REGe lies between -0.14 and 3.13 eV. The formation energy result shows that the Pr dopant in Ge (PrGe) has the lowest formation energy of -0.14 eV, and is most energetically favourable under equilibrium conditions. The REGe induced charge state transition levels within the band gap of Ge. Shallow acceptor levels were induced by both the Eu (EuGe) and Pr (PrGe) dopants in Ge. The CeGe and ErGe exhibited properties of negative-U ordering with effective-U values of -0.85 and -1.07 eV, respectively.

  13. GIOVE: a new detector setup for high sensitivity germanium spectroscopy at shallow depth

    International Nuclear Information System (INIS)

    Heusser, G.; Weber, M.; Hakenmüller, J.; Laubenstein, M.; Lindner, M.; Maneschg, W.; Simgen, H.; Stolzenburg, D.; Strecker, H.

    2015-01-01

    We report on the development and construction of the high-purity germanium spectrometer setup GIOVE (Germanium Inner Outer VEto), recently built and now operated at the shallow underground laboratory of the Max-Planck-Institut für Kernphysik, Heidelberg. Particular attention was paid to the design of a novel passive and active shield, aiming at efficient rejection of environmental and muon induced radiation backgrounds. The achieved sensitivity level of ≤100 μBq kg -1 for primordial radionuclides from U and Th in typical γ ray sample screening measurements is unique among instruments located at comparably shallow depths and can compete with instruments at far deeper underground sites

  14. GIOVE: a new detector setup for high sensitivity germanium spectroscopy at shallow depth

    Energy Technology Data Exchange (ETDEWEB)

    Heusser, G.; Weber, M.; Hakenmueller, J.; Lindner, M.; Maneschg, W.; Simgen, H.; Stolzenburg, D.; Strecker, H. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Laubenstein, M. [Laboratori Nazionali del Gran Sasso, Assergi (Italy)

    2015-11-15

    We report on the development and construction of the high-purity germanium spectrometer setup GIOVE (Germanium Inner Outer VEto), recently built and now operated at the shallow underground laboratory of the Max-Planck-Institut fuer Kernphysik, Heidelberg. Particular attention was paid to the design of a novel passive and active shield, aiming at efficient rejection of environmental and muon induced radiation backgrounds. The achieved sensitivity level of ≤ 100μBq kg{sup -1} for primordial radionuclides from U and Th in typical γ ray sample screening measurements is unique among instruments located at comparably shallow depths and can compete with instruments at far deeper underground sites. (orig.)

  15. Characteristics of an intrinsic germanium detector for measurement of soft x-rays from high-temperature plasmas

    International Nuclear Information System (INIS)

    Kumagai, Katsuaki; Matoba, Tohru; Funahashi, Akimasa; Kawakami, Tomohide

    1976-09-01

    An intrinsic germanium (Ge(I)) detector has been prepared for measurement of soft X-ray spectra from high-temperature tokamak plasmas. Its characteristics of photo-peak efficiency, escape-peak and Compton scattering were calibrated with standard radioisotopes and soft X-rays from the JFT-2a plasma, and compared with those of a lithium-drifted silicon (Si(Li)) detector. Features of the Ge(I) detector are as follows: (i) high detection efficiency in the high energy range, (ii) wide energy range for measurement of soft X-ray spectra, and (iii) low Compton scattering effect in measurement of continuous spectra. Its dead-layer depth is about 0.06μm, and the minimum detectable energies in the Ge(I) detector are similar to those in the Si(Li) detector. The Ge(I) detector is effective for measuring soft X-ray spectra from high-temperature tokamak plasmas. (auth.)

  16. GERDA, a GERmanium Detector Array for the search for neutrinoless ββ decay in 76Ge

    International Nuclear Information System (INIS)

    Pandola, L.; Tomei, C.

    2006-01-01

    The GERDA project, searching for neutrinoless double beta-decay of 76Ge with enriched germanium detectors submerged in a cryogenic bath, has been approved for installation at the Gran Sasso National Laboratory (LNGS), Italy. The GERDA technique is aiming at a dramatic reduction of the background due to radioactive contaminations of the materials surrounding the detectors. This will lead to a sensitivity of about 1026 years on the half-life of neutrinoless double beta decay. Already in the first phase of the experiment, GERDA will be able to investigate with high statistical significance the claimed evidence for neutrinoless double beta decay of 76Ge based on the data of the Heidelberg-Moscow experiment

  17. Large-aperture hybrid photo-detector

    International Nuclear Information System (INIS)

    Kawai, Y.; Nakayama, H.; Kusaka, A.; Kakuno, H.; Abe, T.; Iwasaki, M.; Aihara, H.; Tanaka, M.; Shiozawa, M.; Kyushima, H.; Suyama, M.

    2007-01-01

    We have developed the first complete large-aperture (13-inch diameter) hybrid photo-detector (HPD). The withstanding voltage problem has been overcome and we were able to attain an HPD operating voltage of +20 kV. Adoption of our newly developed backside illumination avalanche diode (AD) was also critical in successfully countering the additional problem of an increase in AD leakage after the activation process. We observed single photon signal timing jitter of under 450 ps in FWHM, electron transit time of ∼12 ns, and clear pulse height separation up to several photoelectron peaks, all greatly superior to the performance of any conventional large-aperture photomultiplier tubes (PMTs). In addition, our HPD has a much simpler structure than conventional large-aperture PMTs, which simplifies mass production and lowers manufacturing cost. We believe that these attributes position our HPD as the most suitable photo-detector for the next generation mega-ton class water-Cherenkov detector, which is expected to be more than 20x larger than the Super-Kamiokande (SK) detector

  18. GIOVE: a new detector setup for high sensitivity germanium spectroscopy at shallow depth

    Energy Technology Data Exchange (ETDEWEB)

    Heusser, G., E-mail: gerd.heusser@mpi-hd.mpg.de; Weber, M., E-mail: marc.weber@mpi-hd.mpg.de; Hakenmüller, J. [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg (Germany); Laubenstein, M. [Laboratori Nazionali del Gran Sasso, Via G. Acitelli 22, 67100, Assergi, AQ (Italy); Lindner, M.; Maneschg, W.; Simgen, H.; Stolzenburg, D.; Strecker, H. [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg (Germany)

    2015-11-09

    We report on the development and construction of the high-purity germanium spectrometer setup GIOVE (Germanium Inner Outer VEto), recently built and now operated at the shallow underground laboratory of the Max-Planck-Institut für Kernphysik, Heidelberg. Particular attention was paid to the design of a novel passive and active shield, aiming at efficient rejection of environmental and muon induced radiation backgrounds. The achieved sensitivity level of ≤100 μBq kg{sup -1} for primordial radionuclides from U and Th in typical γ ray sample screening measurements is unique among instruments located at comparably shallow depths and can compete with instruments at far deeper underground sites.

  19. High resolution gamma-ray spectroscopy at high count rates with a prototype High Purity Germanium detector

    Science.gov (United States)

    Cooper, R. J.; Amman, M.; Vetter, K.

    2018-04-01

    High-resolution gamma-ray spectrometers are required for applications in nuclear safeguards, emergency response, and fundamental nuclear physics. To overcome one of the shortcomings of conventional High Purity Germanium (HPGe) detectors, we have developed a prototype device capable of achieving high event throughput and high energy resolution at very high count rates. This device, the design of which we have previously reported on, features a planar HPGe crystal with a reduced-capacitance strip electrode geometry. This design is intended to provide good energy resolution at the short shaping or digital filter times that are required for high rate operation and which are enabled by the fast charge collection afforded by the planar geometry crystal. In this work, we report on the initial performance of the system at count rates up to and including two million counts per second.

  20. Utilization of concurrently gathered pulser data for complete spectral validation of gamma-ray spectra from germanium detectors

    International Nuclear Information System (INIS)

    Johnson, L.O.; Killian, E.W.; Helmer, R.G.; Coates, R.A.

    1980-01-01

    Some of the capabilities and limitations of using concurrently gathered pulser data for energy calibration, dead time correction, and pile-up loss correction of gamma ray spectra from germanium detectors have been investigated. This report deals with the pulser, charge injection into the charge sensitive preamplifier, hardware separation of gamma and pulser events, and analysis techniques to improve the accuracy of gamma peak area corrections from pulser data. Data are presented indicating achievable short and long term energy calibration stability of better than .01% and accuracy and rate dependent peak area loss corrections of +-1% up to 50,000 pulses per second (pps) and +-2.5% up to 100,000 pps, energy independent

  1. Machine-operated low temperature system for cooling a germanium detector at great depths of the sea

    International Nuclear Information System (INIS)

    Bruederle, F.; Hain, K.; Huebener, J.; Schloss, F.

    1978-07-01

    The report outlines the conceptual design and technical implementation phases of a very reliable low temperature system for long-time cooling of a germanium detector at great depths of the sea. The approach chosen as the solution involves the choise of a proven commercial small-scale refrigeration unit operation by the Gifford-Mc Mahon process, which is modified so as to suit special requirements. Testing for the severe conditions of use is carried out on a jarring table for the critical components and on a rolling test rig for the whole low temperature machine so as to simulate the stresses imposed by ships and high seas. The cooling system designed in this way has demonstrated its full functioning capability in a test conducted at sea. (orig.) 891 HP [de

  2. Focusing of a new germanium counter type : the composite detector. Uses of the TREFLE detector in the EUROGAM multidetector; Mise au point d`un nouveau type de compteur germanium: le detecteur composite. Utilisation du detecteur TREFLE dans le multidetecteur EUROGAM

    Energy Technology Data Exchange (ETDEWEB)

    Han, L

    1995-05-01

    The aim of this thesis is the development of new types of germanium detectors: the composite detectors. Two types of prototypes are then conceived: the stacked planar detector (EDP) and the assembly of coaxial diodes (TREFLE). They are designed for the multidetector EUROGAM destined to the research of nuclear structure at high angular momentum. The four planar diodes of EDP detector were of 7 cm diameter and of 15 to 20 mm thick. The difference between the calculated and measured photopic efficiency is observed. The importance of surface channel induces a weak resistance of neutron damages. The sputtering method for the surface treatment reducing the germanium dead layer as well as a rule of selection concerning the impurity concentration and the thickness of crystal is helpful for the later production of germanium detector. The CLOVER detector consist of for mean size crystals in the same cryostat. The photopic efficiency is much larger than that of the greatest monocrystal detector. And the granulation of composite detector allowed the Doppler broadening correction of gamma ray observed in the nuclear reaction where the recoil velocity is very high. This new type of detector enable the linear polarization measurement of gamma ray. Twenty-four CLOVER detector are actually mounted in the EUROGAM array. The characteristics measured in source as well as in beam, reported in this thesis, meet exactly the charge account. (author). 47 refs., 61 figs., 18 tabs.

  3. First observation of Cherenkov ring images using hybrid photon detectors

    International Nuclear Information System (INIS)

    Albrecht, E.; Wilkinson, G.; Bibby, J.H.; Giles, R.; Harnew, N.; Smale, N.; Brook, N.H.; Halley, A.W.; O'Shea, V.; French, M.; Gibson, V.; Wotton, S.A.; Schomaker, R.

    1998-01-01

    A ring-imaging Cherenkov detector, equipped with hybrid photon detectors, has been operated in a charged-particle beam. Focussed ring images from various particle types were detected using silica aerogel, air and C 4 F 10 gas radiators. The detector, a prototype for the CERN LHC-B experiment, is described and first observations are reported. (orig.)

  4. First observation of Cherenkov ring images using hybrid photon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, E.; Wilkinson, G. [European Organization for Nuclear Research, Geneva (Switzerland). Div. Particle Physics Experiments; Barber, G.; Duane, A.; John, M.; Miller, D.G.; Websdale, D. [Imperial College of Science Technology and Medicine, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Bibby, J.H.; Giles, R.; Harnew, N.; Smale, N. [University of Oxford, Department of Nuclear Physics, Keble Road, Oxford OX1 3RH (United Kingdom); Brook, N.H.; Halley, A.W.; O`Shea, V. [University of Glasgow, Department of Physics, Glasgow G12 8QQ (United Kingdom); French, M. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Gibson, V.; Wotton, S.A. [University of Cambridge, Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE (United Kingdom); Schomaker, R. [Delft Electronic Products BV, 9300 AB Roden (Netherlands)

    1998-07-11

    A ring-imaging Cherenkov detector, equipped with hybrid photon detectors, has been operated in a charged-particle beam. Focussed ring images from various particle types were detected using silica aerogel, air and C{sub 4}F{sub 10} gas radiators. The detector, a prototype for the CERN LHC-B experiment, is described and first observations are reported. (orig.)

  5. Position sensitivity of the proposed segmented germanium detectors for the DESPEC project

    International Nuclear Information System (INIS)

    Khaplanov, A.; Tashenov, S.; Cederwall, B.

    2009-01-01

    The DESPEC HPGe array is a part of the NuSTAR project at FAIR, Germany. It is aimed at the spectroscopy of the stopped decaying exotic nuclei. Segmented γ-ray tracking detectors are proposed for this array in order to maximize detection efficiency and background suppression when searching for very rare events. Two types of detector modules-stacks of three 16-fold segmented planar crystals and 12- and 16-fold segmented clover detectors-have been investigated and compared from the point of view of the achievable position resolution using pulse shape analysis (PSA). To this end, detector signals from realistic γ-ray interactions have been calculated. These signals were treated by PSA in order to reconstruct the photon interaction locations. Comparing the initial interaction locations to the reconstructed ones, it was found that the double-sided strip planar detector yielded position reconstruction errors at least a factor 2 lower than the other detectors considered.

  6. Status report on the International Germanium Experiment

    International Nuclear Information System (INIS)

    Brodzinski, R.L.; Avignone, F.T.; Collar, J.I.; Courant, H.; Garcia, E.; Guerard, C.K.; Hensley, W.K.; Kirpichnikov, I.V.; Miley, H.S.; Morales, A.; Morales, J.; Nunez-Lagos, R.; Osetrov, S.B.; Pogosov, V.S.; Pomansky, A.A.; Puimedon, J.; Reeves, J.H.; Ruddick, K.; Saenz, C.; Salinas, A.; Sarsa, M.L.; Smolnikov, A.A.; Starostin, A.S.; Tamanyan, A.G.; Vasiliev, S.I.; Villar, J.A.

    1993-01-01

    Phase II detector fabrication for the International Germanium Experiment is in progress. Sources of background observed during Phase I are discussed. Cosmogenic 7 Be is measured in germanium. Radium contamination, presumably in electroformed copper, is reported. (orig.)

  7. Status report on the International Germanium Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Brodzinski, R L; Avignone, F.T.; Collar, J I; Courant, H; Garcia, E; Guerard, C K; Hensley, W K; Kirpichnikov, I V; Miley, H S; Morales, A; Morales, J; Nunez-Lagos, R; Osetrov, S B; Pogosov, V S; Pomansky, A A; Puimedon, J; Reeves, J H; Ruddick, K; Saenz, C; Salinas, A; Sarsa, M L; Smolnikov, A A; Starostin, A S; Tamanyan, A G; Vasiliev, S I; Villar, J A [Pacific Northwest Lab., Richland, WA (United States) Univ. of South Carolina, Columbia, SC (United States) Univ. of Minnesota, Minneapolis, MN (United States) Univ. of Zaragoza (Spain) Inst. for Theoretical and Experimental Physics, Moscow (Russian Federation) Inst. for Nuclear Research, Baksan Neutrino Observatory (Russian Federation) Yerevan Physical Inst., Yerevan (Armenia)

    1993-04-01

    Phase II detector fabrication for the International Germanium Experiment is in progress. Sources of background observed during Phase I are discussed. Cosmogenic [sup 7]Be is measured in germanium. Radium contamination, presumably in electroformed copper, is reported. (orig.)

  8. Search for Pauli exclusion principle violating atomic transitions and electron decay with a p-type point contact germanium detector

    Energy Technology Data Exchange (ETDEWEB)

    Abgrall, N.; Bradley, A.W.; Chan, Y.D.; Mertens, S.; Poon, A.W.P. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Arnquist, I.J.; Hoppe, E.W.; Kouzes, R.T.; LaFerriere, B.D.; Orrell, J.L. [Pacific Northwest National Laboratory, Richland, WA (United States); Avignone, F.T. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); Barabash, A.S.; Konovalov, S.I.; Yumatov, V. [National Research Center ' ' Kurchatov Institute' ' Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Bertrand, F.E.; Galindo-Uribarri, A.; Radford, D.C.; Varner, R.L.; White, B.R.; Yu, C.H. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Brudanin, V.; Shirchenko, M.; Vasilyev, S.; Yakushev, E.; Zhitnikov, I. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Busch, M. [Duke University, Department of Physics, Durham, NC (United States); Triangle Universities Nuclear Laboratory, Durham, NC (United States); Buuck, M.; Cuesta, C.; Detwiler, J.A.; Gruszko, J.; Guinn, I.S.; Leon, J.; Robertson, R.G.H. [University of Washington, Department of Physics, Center for Experimental Nuclear Physics and Astrophysics, Seattle, WA (United States); Caldwell, A.S.; Christofferson, C.D.; Dunagan, C.; Howard, S.; Suriano, A.M. [South Dakota School of Mines and Technology, Rapid City, SD (United States); Chu, P.H.; Elliott, S.R.; Goett, J.; Massarczyk, R.; Rielage, K. [Los Alamos National Laboratory, Los Alamos, NM (United States); Efremenko, Yu. [University of Tennessee, Department of Physics and Astronomy, Knoxville, TN (United States); Ejiri, H. [Osaka University, Research Center for Nuclear Physics, Ibaraki, Osaka (Japan); Finnerty, P.S.; Gilliss, T.; Giovanetti, G.K.; Henning, R.; Howe, M.A.; MacMullin, J.; Meijer, S.J.; O' Shaughnessy, C.; Rager, J.; Shanks, B.; Trimble, J.E.; Vorren, K.; Xu, W. [Triangle Universities Nuclear Laboratory, Durham, NC (United States); University of North Carolina, Department of Physics and Astronomy, Chapel Hill, NC (United States); Green, M.P. [North Carolina State University, Department of Physics, Raleigh, NC (United States); Oak Ridge National Laboratory, Oak Ridge, TN (United States); Triangle Universities Nuclear Laboratory, Durham, NC (United States); Guiseppe, V.E.; Tedeschi, D.; Wiseman, C. [University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); Jasinski, B.R. [University of South Dakota, Department of Physics, Vermillion, SD (United States); Keeter, K.J. [Black Hills State University, Department of Physics, Spearfish, SD (United States); Kidd, M.F. [Tennessee Tech University, Cookeville, TN (United States); Martin, R.D. [Queen' s University, Department of Physics, Engineering Physics and Astronomy, Kingston, ON (Canada); Romero-Romero, E. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Tennessee, Department of Physics and Astronomy, Knoxville, TN (United States); Vetter, K. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); University of California, Department of Nuclear Engineering, Berkeley, CA (United States); Wilkerson, J.F. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Triangle Universities Nuclear Laboratory, Durham, NC (United States); University of North Carolina, Department of Physics and Astronomy, Chapel Hill, NC (United States)

    2016-11-15

    A search for Pauli-exclusion-principle-violating K{sub α} electron transitions was performed using 89.5 kg-d of data collected with a p-type point contact high-purity germanium detector operated at the Kimballton Underground Research Facility. A lower limit on the transition lifetime of 5.8 x 10{sup 30} s at 90% C.L. was set by looking for a peak at 10.6 keV resulting from the X-ray and Auger electrons present following the transition. A similar analysis was done to look for the decay of atomic K-shell electrons into neutrinos, resulting in a lower limit of 6.8 x 10{sup 30} s at 90% C.L. It is estimated that the Majorana Demonstrator, a 44 kg array of p-type point contact detectors that will search for the neutrinoless double-beta decay of {sup 76}Ge, could improve upon these exclusion limits by an order of magnitude after three years of operation. (orig.)

  9. Germanium junction detectors. Theoretical and practical factors governing their use in radiation spectrometry

    International Nuclear Information System (INIS)

    Hors, M.; Philis, C.

    1967-01-01

    Semi-conductor detectors have recently greatly increased the possibilities available to nuclear spectroscopists for the study of α, β and γ radiations. Their use in radio-chemistry has encouraged us to study their principle, their mechanism and also the conditions under which they can be used. The first part, which is theoretical, consists of a summary of what should be known concerning the best use of junction detectors, in particular Ge (Li) detectors. The second part, which is experimental, summarizes the laboratory work carried out over a period of one year on Ge (Li) detectors. Stress is laid on the possibilities presented by the use of these detectors as photo-electric spectrometers, and also on the precautions required. Amongst the numerous results presented, the resolution of 2.52 keV obtained for the γ radiation of 145.5 keV for 141 Ce may be particularly noted. (authors) [fr

  10. Advanced far infrared blocked impurity band detectors based on germanium liquid phase epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Christopher Sean [Univ. of California, Berkeley, CA (United States)

    1998-05-01

    This research has shown that epilayers with residual impurity concentrations of 5 x 1013 cm-3 can be grown by producing the purest Pb available in the world. These epilayers have extremely low minority acceptor concentrations, which is ideal for fabrication of IR absorbing layers. The Pb LPE growth of Ge also has the advantageous property of gettering Cu from the epilayer and the substrate. Epilayers have been grown with intentional Sb doping for IR absorption on lightly doped substrates. This research has proven that properly working Ge BIB detectors can be fabricated from the liquid phase as long as pure enough solvents are available. The detectors have responded at proper wavelengths when reversed biased even though the response did not quite reach minimum wavenumbers. Optimization of the Sb doping concentration should further decrease the photoionization energy of these detectors. Ge BIB detectors have been fabricated that respond to 60 cm-1 with low responsivity. Through reduction of the minority residual impurities, detector performance has reached responsivities of 1 A/W. These detectors have exhibited quantum efficiency and NEP values that rival conventional photoconductors and are expected to provide a much more sensitive tool for new scientific discoveries in a number of fields, including solid state studies, astronomy, and cosmology.

  11. Small Pixel Hybrid CMOS X-ray Detectors

    Science.gov (United States)

    Hull, Samuel; Bray, Evan; Burrows, David N.; Chattopadhyay, Tanmoy; Falcone, Abraham; Kern, Matthew; McQuaide, Maria; Wages, Mitchell

    2018-01-01

    Concepts for future space-based X-ray observatories call for a large effective area and high angular resolution instrument to enable precision X-ray astronomy at high redshift and low luminosity. Hybrid CMOS detectors are well suited for such high throughput instruments, and the Penn State X-ray detector lab, in collaboration with Teledyne Imaging Sensors, has recently developed new small pixel hybrid CMOS X-ray detectors. These prototype 128x128 pixel devices have 12.5 micron pixel pitch, 200 micron fully depleted depth, and include crosstalk eliminating CTIA amplifiers and in-pixel correlated double sampling (CDS) capability. We report on characteristics of these new detectors, including the best read noise ever measured for an X-ray hybrid CMOS detector, 5.67 e- (RMS).

  12. Improving axion detection sensitivity in high purity germanium detector based experiments

    Science.gov (United States)

    Xu, Wenqin; Elliott, Steven

    2015-04-01

    Thanks to their excellent energy resolution and low energy threshold, high purity germanium (HPGe) crystals are widely used in low background experiments searching for neutrinoless double beta decay, e.g. the MAJORANA DEMONSTRATOR and the GERDA experiments, and low mass dark matter, e.g. the CDMS and the EDELWEISS experiments. A particularly interesting candidate for low mass dark matter is the axion, which arises from the Peccei-Quinn solution to the strong CP problem and has been searched for in many experiments. Due to axion-photon coupling, the postulated solar axions could coherently convert to photons via the Primakeoff effect in periodic crystal lattices, such as those found in HPGe crystals. The conversion rate depends on the angle between axions and crystal lattices, so the knowledge of HPGe crystal axis is important. In this talk, we will present our efforts to improve the HPGe experimental sensitivity to axions by considering the axis orientations in multiple HPGe crystals simultaneously. We acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program.

  13. Gamma-ray observations of SN 1987A with an array of high-purity germanium detectors

    International Nuclear Information System (INIS)

    Sandie, W.G.; Nakano, G.H.; Chase, L.F. Jr.; Fishman, G.J.; Meegan, C.A.; Wilson, R.B.; Paciesas, W.

    1988-01-01

    A balloon borne gamma-ray spectrometer comprising an array of high-purity n-type germanium (HPGe) detectors having geometric area 119 cm 2 , resolution 2.5 keV at 1.0 MeV, surrounded by an active NaI (Tl) collimator and Compton suppressing anticoincidence shield nominally 10 cm thick, was flown from Alice Springs, Northern Territory, Australia, on May 29--30, 1987, 96 days after the observed neutrino pulse. The average column depth of residual atmosphere in the direction of SN 1987A at float altitude was 6.3 g cm-2 during the observation. SN 1987A was within the 22-deg full-width-half-maximum (FWHM) field of view for about 3300 s during May 29.9--30.3 UT. No excess gamma rays were observed at energies appropriate to the Ni(56)-Co(56) decay chain or from other lines in the energy region from 0.1 to 3.0 MeV. With 80% of the data analyzed, the 3-sigma upper limit obtained for the 1238-keV line from Co(56) at the instrument resolution (about 3 keV) is 1.3 x 10-3 photons cm-2 s-1

  14. Charge Division Readout of a Two-Dimensional Germanium Strip Detector

    National Research Council Canada - National Science Library

    Kroeger, R. A; Inderhees, S. E; Johnson, W. N; Kinzer, R. L; Kurfess, J. D; Gehrels, N

    1993-01-01

    .... The four data channels are stored as an event list for subsequent processing. We form a response map over the detector surface in order to locate the position of each interaction with the spatial resolution of the strip pitch, in our case 9 mm...

  15. Cryogenic germanium detectors for dark matter search: Surface events rejection by charge measurements

    International Nuclear Information System (INIS)

    Broniatowski, A.; Censier, B.; Juillard, A.; Berge, L.

    2006-01-01

    Test experiments have been performed on a Ge detector of the Edelweiss collaboration, combining time-resolved acquisition of the ionization signals with heat measurements. Pulse-shape analysis of the charge signals demonstrates the capability to reject surface events of poor charge collection with energies larger than 50 keV in ionization

  16. Temperature cycling test of planar hyper-pure germanium radiation detector

    International Nuclear Information System (INIS)

    Sakai, Eiji

    1976-01-01

    If a Ge (Li) detector is left at the normal temperature, generally it does not recover its original performance even when it is cooled again with liquid nitrogen, as Li ions in the compensated i zone precipitate by Li drift and it returns to p type which is the state before drift. One of the devices that overcomes this shortcoming is the p-n junction Ge detector, which required the production of high purity Ge single crystals to obtain the thick depletion layer. The planar or coaxial type detectors were produced using the Ge single crystals with impurity concentration of 10 10 /cm 3 and it was recognized that they showed the gamma detecting characteristic nearly equal to Ge (Li) detectors. They are now commercially available from a few companies. The author carried out the temperature-cycling test of the planar type hyperpure Ge detector sold by Nuclear Radiation Developments, Canada. First, applying liquid nitrogen, the leakage current, static capacity, gamma ray-detecting efficiency and energy resolution were measured. Then it was returned to room temperature. Since then, irregular cycling tests were carried out 15 times. The results didn't show any significant change in the gamma ray-detecting efficiency, energy resolution and static capacity. Though leakage current changed between 9.3 and 33 pA, it does not influence on the energy resolution because of small absolute values. It may be said that it is sufficiently stable in the temperature cycling from room temperature to 77 K. (Wakatsuki, Y.)

  17. Investigation of the operational quality of germanium gamma detectors. Estimation of Ge:Li detector survival rates

    International Nuclear Information System (INIS)

    Zerbib, J.-C.

    1980-01-01

    A working group has produced tables of information on gamma semiconductor Ge detectors: Ge(Li) or intrinsic Ge. The information was obtained as a result of enquirres addressed to various laboratories, and concerns 228-sources in France and Belgium [fr

  18. Results of monte Carlo calibrations of a low energy germanium detector

    International Nuclear Information System (INIS)

    Brettner-Messler, R.; Brettner-Messler, R.; Maringer, F.J.

    2006-01-01

    Normally, measurements of the peak efficiency of a gamma ray detector are performed with calibrated samples which are prepared to match the measured ones in all important characteristics like its volume, chemical composition and density. Another way to determine the peak efficiency is to calculate it with special monte Carlo programs. In principle the program 'Pencyl' from the source code 'P.E.N.E.L.O.P.E. 2003' can be used for peak efficiency calibration of a cylinder symmetric detector however exact data for the geometries and the materials is needed. The interpretation of the simulation results is not clear but we found a way to convert the data into values which can be compared to our measurement results. It is possible to find other simulation parameters which perform the same or better results. Further improvements can be expected by longer simulation times and more simulations in the questionable ranges of densities and filling heights. (N.C.)

  19. Gamma ray spectrum of Am 241 in a backscattering geometry using a high purity germanium detector

    International Nuclear Information System (INIS)

    Chong Chon Sing; Ibrahim Salih Elyaseery; Ahmad Shukri Mustapa Kamal; Abdul Aziz Tajuddin

    1997-01-01

    In back scattering geometry using an annular Am-241 source and a HPGE detector has been set up to study both the coherent and incoherent scattering of photon emissions of Am-241 from medium-Z and high-Z elements. Besides the coherent and incoherent scattered peaks of the emissions from the source, the gamma ray spectrum from the different target elements obtained using a microcomputer based multichannel analyser showed the presence of several other peaks. These peaks have been identified to arise from the fluorescence of the targets, the fluorescence of the shielding material Pb, and also as fluorescence sum peaks and X-ray escape peaks of the detector material Ge. The spectra are presented for three target elements viz. Mo, Zn and W

  20. Low background germanium detectors: From environmental laboratory to underground counting facility

    Energy Technology Data Exchange (ETDEWEB)

    Ceuppens, M [Canberra Semiconductor N.V., Geel (Belgium); [Canberra Industries, Inc., Meriden (United States); Verplancke, J [Canberra Semiconductor N.V., Geel (Belgium); [Canberra Industries, Inc., Meriden (United States); Tench, O [Canberra Semiconductor N.V., Geel (Belgium); [Canberra Industries, Inc., Meriden (United States)

    1997-03-01

    Presentation and overview of different Low Level measuring systems ranging from the environmental lab to low-background detection systems and to the deep underground counting facility. Examples and performances for each of these will be given. Attention will be given to the standardised ultra low-background detectors and shields which provide excellent performance without the high cost in time and money associated with custom designed systems. (orig./DG)

  1. Low background germanium detectors: From environmental laboratory to underground counting facility

    International Nuclear Information System (INIS)

    Ceuppens, M.; Verplancke, J.; Tench, O.

    1997-01-01

    Presentation and overview of different Low Level measuring systems ranging from the environmental lab to low-background detection systems and to the deep underground counting facility. Examples and performances for each of these will be given. Attention will be given to the standardised ultra low-background detectors and shields which provide excellent performance without the high cost in time and money associated with custom designed systems. (orig./DG)

  2. A liquid-nitrogen monitor for lithium-drifted germanium detectors

    International Nuclear Information System (INIS)

    Andeweg, A.H.

    1977-11-01

    An instrument has been developed that makes use of a load cell to monitor the liquid nitrogen in the Dewar flask of a lithium-drifted germaniun detector. The contents are recorded on a chart recorder, and an alarm is sounded when the previously set content has been reached. A signal switches off the high-voltage power supply 30 minutes after the alarm is triggered. The calibration of the load-cell monitor is described in an appendix [af

  3. 18F half-life measurement using a high-purity germanium detector

    International Nuclear Information System (INIS)

    Han, Jubong; Lee, K.B.; Park, T.S.; Lee, J.M.; Oh, P.J.; Lee, S.H.; Kang, Y.S.; Ahn, J.K.

    2012-01-01

    The half-life of 18 F has been measured using HPGe detectors with a 137 Cs reference source. The counting ratio of 511 keV γ-rays from 18 F to 622 keV γ-rays from 137 Cs was fitted for the half-life with a weighted least-square method. Uncertainties due to the systematic effects arising from the measurement of a high activity 18 F source were studied in detail. The half-life of 18 F was found to be (109.72±0.19) min. The result is in a good agreement with the recommended value of (109.728±0.019) min evaluated at the Laborotaire National Henri Becquerel (LNHB). - Highlights: ► The 18 F half-life was measured with a reference source and without it using HPGe detectors. ► We found the systematic effect ‘activity dynamic range effect’ by monitoring the counts of the reference source. ► This activity dynamic range effect was corrected by using the reference source method. ► The 18 F half-life using the reference source method was in a good agreement with the recommended value of LNHB.

  4. Development of ultra pure germanium epi layers for blocked impurity band far infrared detectors

    International Nuclear Information System (INIS)

    Lutz, M.P.

    1991-05-01

    The main goals of this paper are: (1) To develop a low-pressure CVD (LPCVD) process that allows epitaxial growth at lower temperatures. Lower temperatures will allow the achievement of a sharp dopant profile at the substrate/epi-layer interface. Less out-diffusion from the substrate would allow the use of thinner epitaxial layers, which would lead to a larger depletion width in the photoactive region. LPCVD also avoids, to a great extent, gas-phase nucleation, which would cause Ge particulates to fall onto the wafer surface during growth. (2) To reduce high levels of oxygen and copper present at the wafer interface, as observed by secondary ion mass spectroscopy (SIMS). In order to achieve high-quality epitaxial layers, it is imperative that the substrate surface be of excellent quality. (3) To make and test detectors, after satisfactory epitaxial layers have been made

  5. A Trigger-less Acquisition System for the EXILL Large Germanium Detectors Array

    International Nuclear Information System (INIS)

    Mutti, Paolo; Blanc, Aurelian; Jentschel, Michael; Koester, Ulli; Ruiz Martinez, Emilio; Soldner, Torsten; France, Gilles de; Simpson, Gary; Ur, Calin A.; Urban, Waldemar

    2013-06-01

    The combination of the intense cold neutron beam available at the PF1b beam position of the Institute Laue- Langevin (ILL) in Grenoble, together with the high detection efficiency of a large array of high purity Ge detectors (HPGe) has offered a unique opportunity for a set of experiments devoted to nuclear spectroscopy on stable isotopes as well as on exotic nuclei produced in the fission process of uranium and plutonium samples. The emitted γ -rays from neutron capture on stable targets as well as from the decay of fission fragments have been acquired in a trigger-less mode to preserve a maximum of information for further off-line treatment. A dedicated fully digital acquisition system using a combination of a 14-bit 100 MS/s digitizers with a Power PC-based VME single board computer has been developed to ensure data collection and real-time processing capabilities. The present article will describe the experimental setup as well as the specific electronic configuration used during the EXILL campaign of measurements with particular emphasis on the technical achievements as well as on the preliminary results obtained in the various experiments. (authors)

  6. Search for neutrinoless double beta decay of Ge-76 with the GERmanium Detector Array '' GERDA ''

    International Nuclear Information System (INIS)

    Brugnera, R.

    2009-01-01

    The study of neutrinoless double beta decay (DBD) is the most powerful approach to the fundamental question if the neutrino is a Majorana particle, i.e. its own anti-particle. The observation of neutrinoless DBD would not only establish the Majorana nature of the neutrino but also represent a determination of its effective mass if the nuclear matrix element is given. So far, the most sensitive results have been obtained with Ge-76, and the group of Klapdor-Kleingrothaus has made a claim of discovery. Future experiments have to reduce radioactive backgrounds to increase the sensitivity. '' GERDA '' is a new double beta-decay experiment which is currently under construction in the INFN Gran Sasso National Laboratory, Italy. It is implementing a new shielding concept by operating bare Ge diodes - enriched in Ge-76 - in high purity liquid argon supplemented by a water shield. The aim of '' GERDA '' is to verify or refute the recent claim of discovery, and, in a second phase, to achieve a two orders of magnitude lower background index than recent experiments, increasing the sensitive mass and reaching exposure of 100 kg yr. It be will discuss design, physics reach, and status of construction of '' GERDA '', and present results from various R efforts including long term stability of bare Ge diodes in cryogenic liquids, material screening, cryostat performance, detector segmentation, cryogenic precision electronics, safety aspects, and Monte Carlo simulations. (author)

  7. Germanium detector calibration according to the standard NF M 60-810 without using radioactive sources

    Energy Technology Data Exchange (ETDEWEB)

    Duda, J. M.; Garell, I.; Losset, Y.; Vichot, L. [CEA de Valduc, Service de Protection Contre Les Rayonnements, 21110 Is sur Tille (France); Chazalet, J.; Tauvel, Y.; Poulet, F. [IUP Genie des Systemes Industriels, Universite Blaise Pascal, Departement de Physique, 24 avenue des Landais, 63177 Aubiere Cedex (France)

    2009-07-01

    In-situ gamma ray spectrometry is used to determine the specific activities of natural and artificial radioactive nuclides in the soil with a good accuracy. This method is very interesting for environmental measurements and leads to soil determination activity. It is a cheaper method than analysis of great amounts of soil samples in the laboratory. As there is no standard soil, detection efficiency can be estimated using either statistical tools or combination of radioactive point sources calibration thanks to mathematical models of NF-M-60-810 standard representing the radionuclide distribution in soil. Experimental determination of detection efficiency requires a large number of operations involving the handling of radioactive standards in the energy range from 0.06 - 2 MeV. For these reasons, detection efficiency model has been determined without using radioactive sources. In order to reduce analytical time and to simplify the efficiency detector calibration, it is possible to associate numerical and deterministic methods and to get a relative accuracy below 25 per cent

  8. Robust hybrid pitch detector for pathologic voice analysis

    OpenAIRE

    Boyanov, B.; Hadjitodorov, S.; Teston, B.; Doskov, D.

    1997-01-01

    International audience; A hybrid speech period (To) detector characterizided by parallel analyses of three speech signals in temporal spectral and cepstral domains and preprocessing for periodic/aperiodic (unvoiced) separation (PAS) is proposed. The preprocessing is realized by analysis in these three domains and PAS by multi layer Perceptron neural network.Two phonations of the wowel "a" of 40 speakers and 62 patients were analyzed. For the proposed detector errors were significantly minimized.

  9. Application of the Broad Energy Germanium detector: A technique for elucidating β-decay schemes which involve daughter nuclei with very low energy excited states

    Energy Technology Data Exchange (ETDEWEB)

    Venhart, M., E-mail: martin.venhart@savba.sk [Institute of Physics, Slovak Academy of Sciences, SK-84511 Bratislava (Slovakia); Wood, J.L. [Department of Physics, Georgia Institute of Technology, Atlanta GA 30332 (United States); Boston, A.J. [Institute of Physics, Slovak Academy of Sciences, SK-84511 Bratislava (Slovakia); Cocolios, T.E. [School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom); KU Leuven, Instituut voor Kern, en Stralingsfysica, B-3001 Leuven (Belgium); Harkness-Brennan, L.J.; Herzberg, R.-D.; Joss, D.T.; Judson, D.S. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Kliman, J.; Matoušek, V. [Institute of Physics, Slovak Academy of Sciences, SK-84511 Bratislava (Slovakia); Motyčák, Š. [Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, SK-812 19 Bratislava (Slovakia); Page, R.D.; Patel, A. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Petrík, K.; Sedlák, M.; Veselský, M. [Institute of Physics, Slovak Academy of Sciences, SK-84511 Bratislava (Slovakia)

    2017-03-21

    A technique for elucidating β-decay schemes of isotopes with a large density of states at low excitation energy has been developed, in which a Broad Energy Germanium (BEGe) detector is used in conjunction with coaxial hyper-pure germanium detectors. The power of this technique is demonstrated using the example of {sup 183}Hg decay. Mass-separated samples of {sup 183}Hg were produced by a deposition of the low-energy radioactive-ion beam delivered by the ISOLDE facility at CERN. The excellent energy resolution of the BEGe detector allowed γ-ray energies to be determined with a precision of a few tens of eV, which was sufficient for the analysis of the Rydberg-Ritz combinations (in conjunction with γ-γ coincidences) in the level scheme. The timestamped structure of the data was used for unambiguous separation of γ rays arising from the decay of {sup 183}Hg from those due to the daughter decays.

  10. Heavy ion radiative capture. A study of the 12C(12C,γ) reaction using a large germanium detector array

    International Nuclear Information System (INIS)

    Jenkins, D.G.; Lister, C.J.; Carpenter, M.P.

    2002-01-01

    A new technique has been developed to investigate the little-explored phenomenon of heavy ion radiative capture. Employing a state-of-the-art germanium detector array (GAMMASPHERE) in a novel fashion as a sum energy calorimeter it is possible to separate the radiative capture channel from overwhelming competition from particle emission channels with exquisite sensitivity. By studying in detail the decay pathways and the intermediate states populated in the decay, it is possible to learn information relevant to the hypothesis of nuclear molecular states. (author)

  11. Monte Carlo modelling of Germanium detectors for the measurement of low energy photons in internal dosimetry: Results of an international comparison

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Ros, J.M. [CIEMAT, Av. Complutense 22, E-28040 Madrid (Spain)], E-mail: jm.gomezros@ciemat.es; Carlan, L. de [CEA DRT/LIST/DETECS/LNHB/LMD, Bat 534, F-91191 Gif sur Yvette, Cedex (France); IRSN DRPH/SDI/LEDI, BP6, F-92262, Fontenay-aux-Roses, Cedex (France); Franck, D. [IRSN DRPH/SDI/LEDI, BP6, F-92262, Fontenay-aux-Roses, Cedex (France); Gualdrini, G. [ENEA ION-IRP, Via dei Colli 16, I-40136 Bologna (Italy); Lis, M.; Lopez, M.A.; Moraleda, M. [CIEMAT, Av. Complutense 22, E-28040 Madrid (Spain); Zankl, M. [GSF - National Research Center for Environment and Health, D-85764 Neuherberg (Germany); Badal, A. [Institut de Tecniques Energetiques, UPC, Diagonal 647, 08028 Barcelona (Spain); Capello, K. [Human Monitoring Laboratory (Canada); Cowan, P. [Serco Assurance, Bld. A32, Winfrith Tech. Centre Winfrith, Dorchester, Dorset DT2 8DH (United Kingdom); Ferrari, P. [ENEA ION-IRP, Via dei Colli 16, I-40136 Bologna (Italy); Heide, B. [Forschungszentrum Karlsruhe, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Henniger, J. [Technical University of Dresden, 01062 Dresden (Germany); Hooley, V. [Serco Assurance, Bld. A32, Winfrith Tech. Centre Winfrith, Dorchester, Dorset DT2 8DH (United Kingdom); Hunt, J. [IRD, Av. Salvador Allende, s/n, Recreio, Rio de Janeiro (Brazil); Kinase, S. [Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Kramer, G.H. [Human Monitoring Laboratory (Canada); Loehnert, D. [Technical University of Dresden, 01062 Dresden (Germany); Lucas, S. [LARN Laboratory, University of Namur, Rue de Bruxelles 61, B-5000 Namur (Belgium)] (and others)

    2008-02-15

    This communication summarizes the results concerning the Monte Carlo (MC) modelling of Germanium detectors for the measurement of low energy photons arising from the 'International comparison on MC modelling for in vivo measurement of Americium in a knee phantom' organized within the EU Coordination Action CONRAD (Coordinated Network for Radiation Dosimetry) as a joint initiative of EURADOS working groups 6 (computational dosimetry) and 7 (internal dosimetry). MC simulations proved to be an applicable way to obtain the calibration factor that needs to be used for in vivo measurements.

  12. Sensitive method for the determination of rare earth elements by radioisotope-excited XRF employing a high purity germanium detector in optimized geometry

    International Nuclear Information System (INIS)

    Lal, M.; Joseph, D.; Patra, P.K.; Bajpal, H.N.

    1993-01-01

    A close-coupled side-source geometrical configuration is proposed for obtaining a high detection sensitivity for rare earth elements (57 ≤ Z ≤ 69) by radioisotope-excited energy-dispersive x-ray fluorescence spectrometry. In this configuration a disc source of 241 Am (100 mCi), a high-purity germanium detector and thin samples of rare earth elements on a Mylar backing are employed in an optimized geometry to achieve detection limits in the range 20-50 ng for these elements in a counting time of 1 h. (author)

  13. Monte Carlo simulation of gamma-ray interactions in an over-square high-purity germanium detector for in-vivo measurements

    Science.gov (United States)

    Saizu, Mirela Angela

    2016-09-01

    The developments of high-purity germanium detectors match very well the requirements of the in-vivo human body measurements regarding the gamma energy ranges of the radionuclides intended to be measured, the shape of the extended radioactive sources, and the measurement geometries. The Whole Body Counter (WBC) from IFIN-HH is based on an “over-square” high-purity germanium detector (HPGe) to perform accurate measurements of the incorporated radionuclides emitting X and gamma rays in the energy range of 10 keV-1500 keV, under conditions of good shielding, suitable collimation, and calibration. As an alternative to the experimental efficiency calibration method consisting of using reference calibration sources with gamma energy lines that cover all the considered energy range, it is proposed to use the Monte Carlo method for the efficiency calibration of the WBC using the radiation transport code MCNP5. The HPGe detector was modelled and the gamma energy lines of 241Am, 57Co, 133Ba, 137Cs, 60Co, and 152Eu were simulated in order to obtain the virtual efficiency calibration curve of the WBC. The Monte Carlo method was validated by comparing the simulated results with the experimental measurements using point-like sources. For their optimum matching, the impact of the variation of the front dead layer thickness and of the detector photon absorbing layers materials on the HPGe detector efficiency was studied, and the detector’s model was refined. In order to perform the WBC efficiency calibration for realistic people monitoring, more numerical calculations were generated simulating extended sources of specific shape according to the standard man characteristics.

  14. Quantum Efficiency of Hybrid Photon Detectors for the LHCb RICH

    CERN Document Server

    Lambert, R W

    2008-01-01

    The production of Hybrid Photon Detectors to be used as the single-photon sensors for the RICH detectors of the LHCb experiment has recently finished. We present the quantum efficiency measurements of the entire sample of 550 tubes. The manufacturer has succeeded in consistently improving the quantum efficiency of the employed S20-type multi-alkali photocathode above our expectations, by a relative 27 % integrated over the energy spectrum. We also report measurements of the vacuum quality using the photocurrent of the device as a monitor for possible vacuum degradation.

  15. Test Beam Results of Geometry Optimized Hybrid Pixel Detectors

    CERN Document Server

    Becks, K H; Grah, C; Mättig, P; Rohe, T

    2006-01-01

    The Multi-Chip-Module-Deposited (MCM-D) technique has been used to build hybrid pixel detector assemblies. This paper summarises the results of an analysis of data obtained in a test beam campaign at CERN. Here, single chip hybrids made of ATLAS pixel prototype read-out electronics and special sensor tiles were used. They were prepared by the Fraunhofer Institut fuer Zuverlaessigkeit und Mikrointegration, IZM, Berlin, Germany. The sensors feature an optimized sensor geometry called equal sized bricked. This design enhances the spatial resolution for double hits in the long direction of the sensor cells.

  16. Hybrid Detectors for Neutrons Combining Phenyl- Polysiloxanes with 3D Silicon Detectors

    International Nuclear Information System (INIS)

    Dalla Palma, Matteo; Quaranta, Alberto; Collazuol, Gianmaria; Carturan, Sara; Cinausero, Marco; Gramegna, Fabiana; Marchi, Tommaso; Dalla Betta, Gian-Franco; Mendicino, Roberto; Povoli, Marco; Boscardin, Maurizio; Giacomini, Gabriele; Ronchin, Sabina; Zorzi, Nicola

    2013-06-01

    We report on the initial results of a research project aimed at the development hybrid detectors for fast neutrons by combining a phenyl-polysiloxane-based converter with a 3D silicon detector. To this purpose, new 3D sensor structures have been designed, fabricated and electrically tested, showing low depletion voltage and good leakage current. Moreover, the radiation detection capability of 3D sensors was tested by measuring the signals recorded from alpha particles, gamma rays, and pulsed lasers. The converter has been poured into the 3D cavities with excellent coupling, as confirmed by cross-section SEM analyses. Preliminary tests with neutrons have been carried out on the first hybrid detector prototypes at the CN accelerator of INFN LNL. The device design and technology are discussed, along with the first results from the electrical and functional characterization. (authors)

  17. Ab‐initio study of germanium di-interstitial using a hybrid functional (HSE)

    Energy Technology Data Exchange (ETDEWEB)

    Igumbor, E., E-mail: elgumuk@gmail.com [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa); Department of Mathematics and Physical Sciences, Samuel Adegboyega University, Km 1 Ogwa/Ehor Rd, Ogwa, Edo State (Nigeria); Ouma, C.N.M.; Webb, G. [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa); Meyer, W.E., E-mail: wmeyer@up.ac.za [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa)

    2016-01-01

    In this work, we present ab‐initio calculation results of Ge di-interstitials (I{sub 2(Ge)}) in the framework of the density functional theory (DFT) using the Heyd, Scuseria, and Ernzerhof (HSE) hybrid functional. The formation energy, transition levels and minimum energy configurations were obtained for I{sub 2(Ge)} −2, −1, 0, +1 and +2 charge states. The calculated formation energies show that for all charge states of I{sub 2(Ge)}, the double tetrahedral (T) configuration formed the most stable defect with a binding energy of 1.24 eV in the neutral state. We found the (+2/+1) charge state transition level for the T lying below the conduction band minimum and (+2/+1) for the split[110]-tetrahedral configuration lying deep at 0.41 eV above the valence band maximum. The di-interstitials in Ge exhibited the properties of both shallow and deep donor levels at (+2/+1) within the band gap and depending on the configurations. I{sub 2(Ge)} gave rise to negative-U, with effective-U values of −0.61 and −1.6 eV in different configurations. We have compared our results with calculations of di-interstitials in silicon and available experimental data.

  18. Imaging Hybrid Photon Detectors with a Reflective Photocathode

    CERN Document Server

    Ferenc, D

    2000-01-01

    Modern epitaxially grown photocathodes, like GaAsP, bring a very high inherent quantum efficiency, but are rather expensive due to the complicated manufacturing and mounting process. We argue that such photocathodes could be used in reflective mode, in order to avoid the risky and expensive removal of the epitaxial growth substrate. Besides that the quantum efficiency should increase considerably. In this paper we present results of the development of large imaging Hybrid Photon Detectors (HPDs), particularly designed for such reflective photocathodes.

  19. Characterizing Subpixel Spatial Resolution of a Hybrid CMOS Detector

    Science.gov (United States)

    Bray, Evan; Burrows, Dave; Chattopadhyay, Tanmoy; Falcone, Abraham; Hull, Samuel; Kern, Matthew; McQuaide, Maria; Wages, Mitchell

    2018-01-01

    The detection of X-rays is a unique process relative to other wavelengths, and allows for some novel features that increase the scientific yield of a single observation. Unlike lower photon energies, X-rays liberate a large number of electrons from the silicon absorber array of the detector. This number is usually on the order of several hundred to a thousand for moderate-energy X-rays. These electrons tend to diffuse outward into what is referred to as the charge cloud. This cloud can then be picked up by several pixels, forming a specific pattern based on the exact incident location. By conducting the first ever “mesh experiment" on a hybrid CMOS detector (HCD), we have experimentally determined the charge cloud shape and used it to characterize responsivity of the detector with subpixel spatial resolution.

  20. Fission-product yields for thermal-neutron fission of 243Cm determined from measurements with a high-resolution low-energy germanium gamma-ray detector

    International Nuclear Information System (INIS)

    Merriman, L.D.

    1984-04-01

    Cumulative fission-product yields have been determined for 13 gamma rays emitted during the decay of 12 fission products created by thermal-neutron fission of 243 Cm. A high-resolution low-energy germanium detector was used to measure the pulse-height spectra of gamma rays emitted from a 77-nanogram sample of 243 Cm after the sample had been irradiated by thermal neutrons. Analysis of the data resulted in the identification and matching of gamma-ray energies and half-lives to individual radioisotopes. From these results, 12 cumulative fission product yields were deduced for radionuclides with half-lives between 4.2 min and 84.2 min. 7 references

  1. Electron imaging with Medipix2 hybrid pixel detector

    International Nuclear Information System (INIS)

    McMullan, G.; Cattermole, D.M.; Chen, S.; Henderson, R.; Llopart, X.; Summerfield, C.; Tlustos, L.; Faruqi, A.R.

    2007-01-01

    The electron imaging performance of Medipix2 is described. Medipix2 is a hybrid pixel detector composed of two layers. It has a sensor layer and a layer of readout electronics, in which each 55 μmx55 μm pixel has upper and lower energy discrimination and MHz rate counting. The sensor layer consists of a 300 μm slab of pixellated monolithic silicon and this is bonded to the readout chip. Experimental measurement of the detective quantum efficiency, DQE(0) at 120 keV shows that it can reach ∼85% independent of electron exposure, since the detector has zero noise, and the DQE(Nyquist) can reach ∼35% of that expected for a perfect detector (4/π 2 ). Experimental measurement of the modulation transfer function (MTF) at Nyquist resolution for 120 keV electrons using a 60 keV lower energy threshold, yields a value that is 50% of that expected for a perfect detector (2/π). Finally, Monte Carlo simulations of electron tracks and energy deposited in adjacent pixels have been performed and used to calculate expected values for the MTF and DQE as a function of the threshold energy. The good agreement between theory and experiment allows suggestions for further improvements to be made with confidence. The present detector is already very useful for experiments that require a high DQE at very low doses

  2. Development of hybrid low-pressure MSGC neutron detectors

    International Nuclear Information System (INIS)

    Gebauer, B.; Alimov, S.S.; Klimov, A.Yu.; Levchanovski, F.V.; Litvinenko, E.I.; Nikiforov, A.S.; Prikhodko, V.I.; Richter, G.; Rogov, V.; Schulz, Ch.; Shashkin, V.I.; Wilhelm, M.; Wilpert, Th.

    2004-01-01

    For very high rate and resolution time-resolved experiments at next generation pulsed spallation neutron sources like ESS large-area hybrid low-pressure micro-strip gas chamber detectors are being developed. Due to their thin composite converter foil and exponential gas multiplication commencing at the converter surfaces the detectors are free of parallax, and according to detailed modeling the very high transverse and longitudinal localization accuracies in the conversion and gas multiplication processes allow position and time resolutions of ∼100 μm and 8 cps. This will open up novel applications based on time-of-flight (TOF) and single-event detection with very high dynamic range, replacing integrating CCD and image plate detectors, e.g. in radiography/tomography, TOF Laue diffraction, single crystal diffraction and focusing low-Q SANS. In this conference report new results concerning the technical realization of this detector system are reported in conjunction with a brief summary of the detector principle and with reference to earlier results

  3. Electron imaging with Medipix2 hybrid pixel detector.

    Science.gov (United States)

    McMullan, G; Cattermole, D M; Chen, S; Henderson, R; Llopart, X; Summerfield, C; Tlustos, L; Faruqi, A R

    2007-01-01

    The electron imaging performance of Medipix2 is described. Medipix2 is a hybrid pixel detector composed of two layers. It has a sensor layer and a layer of readout electronics, in which each 55 microm x 55 microm pixel has upper and lower energy discrimination and MHz rate counting. The sensor layer consists of a 300 microm slab of pixellated monolithic silicon and this is bonded to the readout chip. Experimental measurement of the detective quantum efficiency, DQE(0) at 120 keV shows that it can reach approximately 85% independent of electron exposure, since the detector has zero noise, and the DQE(Nyquist) can reach approximately 35% of that expected for a perfect detector (4/pi(2)). Experimental measurement of the modulation transfer function (MTF) at Nyquist resolution for 120 keV electrons using a 60 keV lower energy threshold, yields a value that is 50% of that expected for a perfect detector (2/pi). Finally, Monte Carlo simulations of electron tracks and energy deposited in adjacent pixels have been performed and used to calculate expected values for the MTF and DQE as a function of the threshold energy. The good agreement between theory and experiment allows suggestions for further improvements to be made with confidence. The present detector is already very useful for experiments that require a high DQE at very low doses.

  4. Performance of a thermal imager employing a hybrid pyroelectric detector array with MOSFET readout

    International Nuclear Information System (INIS)

    Watton, R.; Mansi, M.V.

    1988-01-01

    A thermal imager employing a two-dimensional hybrid array of pyroelectric detectors with MOSFET readout has been built. The design and theoretical performance of the detector are discussed, and the results of performance measurements are presented. 8 references

  5. Electron imaging with Medipix2 hybrid pixel detector

    CERN Document Server

    McMullan, G; Chen, S; Henderson, R; Llopart, X; Summerfield, C; Tlustos, L; Faruqi, A R

    2007-01-01

    The electron imaging performance of Medipix2 is described. Medipix2 is a hybrid pixel detector composed of two layers. It has a sensor layer and a layer of readout electronics, in which each 55 μm×55 μm pixel has upper and lower energy discrimination and MHz rate counting. The sensor layer consists of a 300 μm slab of pixellated monolithic silicon and this is bonded to the readout chip. Experimental measurement of the detective quantum efficiency, DQE(0) at 120 keV shows that it can reach 85% independent of electron exposure, since the detector has zero noise, and the DQE(Nyquist) can reach 35% of that expected for a perfect detector (4/π2). Experimental measurement of the modulation transfer function (MTF) at Nyquist resolution for 120 keV electrons using a 60 keV lower energy threshold, yields a value that is 50% of that expected for a perfect detector (2/π). Finally, Monte Carlo simulations of electron tracks and energy deposited in adjacent pixels have been performed and used to calculate expected v...

  6. Detection of secondary electrons with pixelated hybrid semiconductor detectors

    International Nuclear Information System (INIS)

    Gebert, Ulrike Sonja

    2011-01-01

    Within the scope of this thesis, secondary electrons were detected with a pixelated semiconductor detector named Timepix. The Timepix detector consists of electronics and a sensor made from a semiconductor material. The connection of sensor and electronics is done for each pixel individually using bump bonds. Electrons with energies above 3 keV can be detected with the sensor. One electron produces a certain amount of electron-hole pairs according to its energy. The charge then drifts along an electric field to the pixel electronics, where it induces an electric signal. Even without a sensor it is possible to detect an electric signal from approximately 1000 electrons directly in the pixel electronics. Two different detector systems to detect secondary electrons using the Timepix detector were investigated during this thesis. First of all, a hybrid photon detector (HPD) was used to detect single photoelectrons. The HPD consists of a vacuum vessel with an entrance window and a cesium iodine photocathode at the inner surface of the window. Photoelectrons are released from the photocathode by incident light and are accelerated in an electric field towards the Timepix detector, where the point of interaction and the arrival time of the electron is determined. With a proximity focusing setup, a time resolution of 12 ns (with an acceleration voltage of 20 kV between photocathode and Timepix detector) was obtained. The HPD examined in this thesis showed a strong dependence of the dark rate form the acceleration voltage and the pressure in the vacuum vessel. At a pressure of few 10 -5 mbar and an acceleration voltage of 20 kV, the dark rate was about 800 Hz per mm 2 area of the read out photocathode. One possibility to reduce the dark rate is to identify ion feedback events. With a slightly modified setup it was possible to reduce the dark rate to 0.5 Hz/mm 2 . To achieve this, a new photocathode was mounted in a shorter distance to the detector. The measurements where

  7. Tunable conductivity in mesoporous germanium

    Science.gov (United States)

    Beattie, Meghan N.; Bioud, Youcef A.; Hobson, David G.; Boucherif, Abderraouf; Valdivia, Christopher E.; Drouin, Dominique; Arès, Richard; Hinzer, Karin

    2018-05-01

    Germanium-based nanostructures have attracted increasing attention due to favourable electrical and optical properties, which are tunable on the nanoscale. High densities of germanium nanocrystals are synthesized via electrochemical etching, making porous germanium an appealing nanostructured material for a variety of applications. In this work, we have demonstrated highly tunable electrical conductivity in mesoporous germanium layers by conducting a systematic study varying crystallite size using thermal annealing, with experimental conductivities ranging from 0.6 to 33 (×10‑3) Ω‑1 cm‑1. The conductivity of as-prepared mesoporous germanium with 70% porosity and crystallite size between 4 and 10 nm is shown to be ∼0.9 × 10‑3 Ω‑1 cm‑1, 5 orders of magnitude smaller than that of bulk p-type germanium. Thermal annealing for 10 min at 400 °C further reduced the conductivity; however, annealing at 450 °C caused a morphological transformation from columnar crystallites to interconnecting granular crystallites and an increase in conductivity by two orders of magnitude relative to as-prepared mesoporous germanium caused by reduced influence of surface states. We developed an electrostatic model relating the carrier concentration and mobility of p-type mesoporous germanium to the nanoscale morphology. Correlation within an order of magnitude was found between modelled and experimental conductivities, limited by variation in sample uniformity and uncertainty in void size and fraction after annealing. Furthermore, theoretical results suggest that mesoporous germanium conductivity could be tuned over four orders of magnitude, leading to optimized hybrid devices.

  8. Germanium soup

    Science.gov (United States)

    Palmer, Troy A.; Alexay, Christopher C.

    2006-05-01

    This paper addresses the variety and impact of dispersive model variations for infrared materials and, in particular, the level to which certain optical designs are affected by this potential variation in germanium. This work offers a method for anticipating and/or minimizing the pitfalls such potential model variations may have on a candidate optical design.

  9. Recent X-ray hybrid CMOS detector developments and measurements

    Science.gov (United States)

    Hull, Samuel V.; Falcone, Abraham D.; Burrows, David N.; Wages, Mitchell; Chattopadhyay, Tanmoy; McQuaide, Maria; Bray, Evan; Kern, Matthew

    2017-08-01

    The Penn State X-ray detector lab, in collaboration with Teledyne Imaging Sensors (TIS), have progressed their efforts to improve soft X-ray Hybrid CMOS detector (HCD) technology on multiple fronts. Having newly acquired a Teledyne cryogenic SIDECARTM ASIC for use with HxRG devices, measurements were performed with an H2RG HCD and the cooled SIDECARTM. We report new energy resolution and read noise measurements, which show a significant improvement over room temperature SIDECARTM operation. Further, in order to meet the demands of future high-throughput and high spatial resolution X-ray observatories, detectors with fast readout and small pixel sizes are being developed. We report on characteristics of new X-ray HCDs with 12.5 micron pitch that include in-pixel CDS circuitry and crosstalk-eliminating CTIA amplifiers. In addition, PSU and TIS are developing a new large-scale array Speedster-EXD device. The original 64 × 64 pixel Speedster-EXD prototype used comparators in each pixel to enable event driven readout with order of magnitude higher effective readout rates, which will now be implemented in a 550 × 550 pixel device. Finally, the detector lab is involved in a sounding rocket mission that is slated to fly in 2018 with an off-plane reflection grating array and an H2RG X-ray HCD. We report on the planned detector configuration for this mission, which will increase the NASA technology readiness level of X-ray HCDs to TRL 9.

  10. Compton scatter in germanium and its effect on imaging with gamma-ray position-sensitive detectors

    International Nuclear Information System (INIS)

    Sherman, I.S.; Strauss, M.G.; Brenner, R.

    1978-01-01

    The spatial spread due to Compton scatter in Ge was measured to study the reduction in image contrast and signal-to-noise ratio (S/N) resulting from erroneous readout in Ge position-sensitive detectors. The step response revealing this spread was obtained by scanning with a 122 keV γ-ray beam across a boundary of two sectors of a slotted coaxial Ge(Li) detector that is 40 mm diameter by 22 mm long. The derived line-spread function at 140 keV (/sup 99m/Tc) exhibits much shorter but thicker tails than those due to scatter in tissue as observed with a NaI detector through 5.5 cm of scattering material. Convolutions of rectangular profiles of voids with the Ge(Li) line-spread function show marked deterioration in contrast for voids less than 10 mm across, which in turn results in even greater deterioration of the S/N. As a result, the contrast for voids in Ge images is only 20 to 30 percent higher than that in NaI and the S/N is only comparable for equal detector areas. The degradation in image contrast due to scatter in Ge detectors can be greatly reduced by either using thin detectors (approximately 5 mm), where scatter virtually does not exist, or by using thicker detectors and rejecting scatter electronically. To reduce the effects of scatter on the S/N as well as on contrast, the erroneous position readouts must actually be corrected. A more realizable approach to achieving the ultimate potential of Ge detectors may be a scanning array of discrete detectors (not position sensitive) in which readout is not affected by scatter

  11. A search for particle dark matter using cryogenic germanium and silicon detectors in the one- and two- tower runs of CDMS-II at Soudan

    International Nuclear Information System (INIS)

    Ogburn, Reuben Walter IV

    2008-01-01

    Images of the Bullet Cluster of galaxies in visible light, X-rays, and through gravitational lensing confirm that most of the matter in the universe is not composed of any known form of matter. The combined evidence from the dynamics of galaxies and clusters of galaxies, the cosmic microwave background, big bang nucleosynthesis, and other observations indicates that 80% of the universe's matter is dark, nearly collisionless, and cold. The identify of the dar, matter remains unknown, but weakly interacting massive particles (WIMPs) are a very good candidate. They are a natural part of many supersymmetric extensions to the standard model, and could be produced as a nonrelativistic, thermal relic in the early universe with about the right density to account for the missing mass. The dark matter of a galaxy should exist as a spherical or ellipsoidal cloud, called a 'halo' because it extends well past the edge of the visible galaxy. The Cryogenic Dark Matter Search (CDMS) seeks to directly detect interactions between WIMPs in the Milky Way's galactic dark matter halo using crystals of germanium and silicon. Our Z-sensitive ionization and phonon ('ZIP') detectors simultaneously measure both phonons and ionization produced by particle interactions. In order to find very rare, low-energy WIMP interactions, they must identify and reject background events caused by environmental radioactivity, radioactive contaminants on the detector,s and cosmic rays. In particular, sophisticated analysis of the timing of phonon signals is needed to eliminate signals caused by beta decays at the detector surfaces. This thesis presents the firs two dark matter data sets from the deep underground experimental site at the Soudan Underground Laboratory in Minnesota. These are known as 'Run 118', with six detectors (1 kg Ge, 65.2 live days before cuts) and 'Run 119', with twelve detectors (1.5 kg Ge, 74.5 live days before cuts). They have analyzed all data from the two runs together in a single

  12. Capacitively coupled hybrid pixel assemblies for the CLIC vertex detector

    CERN Document Server

    AUTHOR|(SzGeCERN)734627; Benoit, Mathieu; Dannheim, Dominik; Dette, Karola; Hynds, Daniel; Kulis, Szymon; Peric, Ivan; Petric, Marko; Redford, Sophie; Sicking, Eva; Valerio, Pierpaolo

    2016-01-01

    The vertex detector at the proposed CLIC multi-TeV linear e+e- collider must have minimal material content and high spatial resolution, combined with accurate time-stamping to cope with the expected high rate of beam-induced backgrounds. One of the options being considered is the use of active sensors implemented in a commercial high-voltage CMOS process, capacitively coupled to hybrid pixel ASICs. A prototype of such an assembly, using two custom designed chips (CCPDv3 as active sensor glued to a CLICpix readout chip), has been characterised both in the lab and in beam tests at the CERN SPS using 120 GeV/c positively charged hadrons. Results of these characterisation studies are presented both for single and dual amplification stages in the active sensor. Pixel cross-coupling results are also presented, showing the sensitivity to placement precision and planarity of the glue layer.

  13. Final results of the EDELWEISS-II WIMP search using a 4-kg array of cryogenic germanium detectors with interleaved electrodes

    International Nuclear Information System (INIS)

    Armengaud, E.; Augier, C.; Benoit, A.; Berge, L.; Bluemer, J.; Broniatowski, A.; Brudanin, V.; Censier, B.; Chardin, G.; Chapellier, M.; Charlieux, F.; Coulter, P.; Cox, G.A.; Defay, X.; De Jesus, M.; Dolgorouki, Y.; Domange, J.; Dumoulin, L.

    2011-01-01

    The EDELWEISS-II Collaboration has completed a direct search for WIMP dark matter with an array of ten 400-g cryogenic germanium detectors in operation at the Laboratoire Souterrain de Modane. The combined use of thermal phonon sensors and charge collection electrodes with an interleaved geometry enables the efficient rejection of γ-induced radioactivity as well as near-surface interactions. A total effective exposure of 384 kg d has been achieved, mostly coming from fourteen months of continuous operation. Five nuclear recoil candidates are observed above 20 keV, while the estimated background is 3.0 events. The result is interpreted in terms of limits on the cross-section of spin-independent interactions of WIMPs and nucleons. A cross-section of 4.4x10 -8 pb is excluded at 90%CL for a WIMP mass of 85 GeV. New constraints are also set on models where the WIMP-nucleon scattering is inelastic.

  14. Hard X-ray polarimetry with position sensitve germanium detectors. Studies of the recombination transitions into highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Tashenov, Stanislav

    2005-07-01

    In this work a first study of the photon polarization for the process of radiative recombination has been performed. This was done at the ESR storage ring at GSI for uranium ions colliding with N2 at various collision energies. For this measurement a high purity Ge Pixel Detector with a 4 x 4 segmentation matrix was applied. The investigation was performed at the Gas-jet target of the ESR. The detector was placed at 60 and 90 observation angles. The sensitivity of the Compton scattering effect to the linear polarization of the X-Ray radiation was employed for the polarization measurement. Detailed investigations of the scattering and geometrical effects inside the detector were performed in order to develop a method to interpret the experimental data and extract the degree of the linear polarization in the hard X-Ray regime with a high precision. A special emphasis was given to the geometry of the detector and it's influence on the measured pixel-to-pixel Compton scattering intensities. The developed method enabled to achieve a precision of the order of 10% with the Pixel Detector which is dominated by the statistical uncertainties. The obtained results show a good agreement with the theoretical values derived from the exact relativistic calculations. For the case of the linear polarization of the K-REC photons, the measured data con rm the theoretical prediction that strong depolarization effects occur for high projectile charges in the forward hemisphere. The latter is in disagreement with the nonrelativistic theory which predicts a 100 % polarization regardless of the emission angle. (orig.)

  15. Hard X-ray polarimetry with position sensitve germanium detectors. Studies of the recombination transitions into highly charged ions

    International Nuclear Information System (INIS)

    Tashenov, Stanislav

    2005-01-01

    In this work a first study of the photon polarization for the process of radiative recombination has been performed. This was done at the ESR storage ring at GSI for uranium ions colliding with N2 at various collision energies. For this measurement a high purity Ge Pixel Detector with a 4 x 4 segmentation matrix was applied. The investigation was performed at the Gas-jet target of the ESR. The detector was placed at 60 and 90 observation angles. The sensitivity of the Compton scattering effect to the linear polarization of the X-Ray radiation was employed for the polarization measurement. Detailed investigations of the scattering and geometrical effects inside the detector were performed in order to develop a method to interpret the experimental data and extract the degree of the linear polarization in the hard X-Ray regime with a high precision. A special emphasis was given to the geometry of the detector and it's influence on the measured pixel-to-pixel Compton scattering intensities. The developed method enabled to achieve a precision of the order of 10% with the Pixel Detector which is dominated by the statistical uncertainties. The obtained results show a good agreement with the theoretical values derived from the exact relativistic calculations. For the case of the linear polarization of the K-REC photons, the measured data con rm the theoretical prediction that strong depolarization effects occur for high projectile charges in the forward hemisphere. The latter is in disagreement with the nonrelativistic theory which predicts a 100 % polarization regardless of the emission angle. (orig.)

  16. A simple methodology for characterization of germanium coaxial detectors by using Monte Carlo simulation and evolutionary algorithms

    International Nuclear Information System (INIS)

    Guerra, J.G.; Rubiano, J.G.; Winter, G.; Guerra, A.G.; Alonso, H.; Arnedo, M.A.; Tejera, A.; Gil, J.M.; Rodríguez, R.; Martel, P.; Bolivar, J.P.

    2015-01-01

    The determination in a sample of the activity concentration of a specific radionuclide by gamma spectrometry needs to know the full energy peak efficiency (FEPE) for the energy of interest. The difficulties related to the experimental calibration make it advisable to have alternative methods for FEPE determination, such as the simulation of the transport of photons in the crystal by the Monte Carlo method, which requires an accurate knowledge of the characteristics and geometry of the detector. The characterization process is mainly carried out by Canberra Industries Inc. using proprietary techniques and methodologies developed by that company. It is a costly procedure (due to shipping and to the cost of the process itself) and for some research laboratories an alternative in situ procedure can be very useful. The main goal of this paper is to find an alternative to this costly characterization process, by establishing a method for optimizing the parameters of characterizing the detector, through a computational procedure which could be reproduced at a standard research lab. This method consists in the determination of the detector geometric parameters by using Monte Carlo simulation in parallel with an optimization process, based on evolutionary algorithms, starting from a set of reference FEPEs determined experimentally or computationally. The proposed method has proven to be effective and simple to implement. It provides a set of characterization parameters which it has been successfully validated for different source-detector geometries, and also for a wide range of environmental samples and certified materials. - Highlights: • A computational method for characterizing an HPGe spectrometer has been developed. • Detector characterized using as reference photopeak efficiencies obtained experimentally or by Monte Carlo calibration. • The characterization obtained has been validated for samples with different geometries and composition. • Good agreement

  17. Cosmogenically-produced isotopes in natural and enriched high-purity germanium detectors for the MAJORANA DEMONSTRATOR

    Science.gov (United States)

    Gilliss, Thomas; MAJORANA DEMONSTRATOR Collaboration

    2017-01-01

    The MAJORANA DEMONSTRATOR advances toward measurements of the neutrinoless double-beta decay of 76Ge. Detectors employed in the DEMONSTRATOR are subject to cosmogenic spallation during production and processing, resulting in activation of certain long-lived radioisotopes. Activation of these cosmogenic isotopes is mitigated by shielded storage of detectors and through underground operation of the DEMONSTRATOR at the 4850 ft level of the Sanford Underground Research Facility. In this work, we explore the appearance and reduction of cosmogenic contributions to the DEMONSTRATOR background spectrum. This work is supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics and Nuclear Physics Programs of the National Science Foundation, and the Sanford Underground Research Facility.

  18. Fast neutron detection with germanium detectors: computation of response functions for the 692 keV inelastic scattering peak

    International Nuclear Information System (INIS)

    Fehrenbacher, G.; Meckbach, R.; Paretzke, H.G.

    1996-01-01

    The dependence of the shape of the right-sided broadening of the inelastic scattering peak at 692 keV in the pulse-height distribution measured with a Ge detector in fast neutron fields on the energy of the incident neutrons has been analyzed. A model incorporating the process contributing to the energy deposition that engender the peak, including the partitioning of the energy deposition by the Ge recoils, was developed. With a Monte Carlo code based on this model, the detector response associated with this peak was computed and compared with results of measurements with quasi-monoenergetic neutrons for energies between 0.88 and 2.1 MeV. A set of 80 response functions for neutron energies in the range from the reaction threshold at 0.7 to 6 MeV was computed, which will serve as a starting point for methods, which aim at obtaining information on the spectral distribution of fast neutron fields for this energy range from measurements with a Ge detector. (orig.)

  19. Development of an external readout electronics for a hybrid photon detector

    CERN Document Server

    Uyttenhove, Simon; Tichon, Jacques; Garcia, Salvador

    The pixel hybrid photon detectors currently installed in the LHCb Cherenkov system encapsulate readout electronics in the vacuum tube envelope. The LHCb upgrade and the new trigger system will require their replacement with new photon detectors. The baseline photon detector candidate is the multi-anode photomultiplier. A hybrid photon detector with external readout electronics has been proposed as a backup option. This master thesis covers a R & D phase to investigate this latter concept. Extensive studies of the initial electronics system underlined the noise contributions from the Beetle chip used as front-end readout ASIC and from the ceramic carrier of the photon detector. New front-end electronic boards have been developed and made fully compatible with the existing LHCb-RICH infrastructure. With this compact readout system, Cherenkov photons have been successfully detected in a real particle beam environment. The proof-of-concept of a hybrid photon detector with external readout electronics was val...

  20. First 10 kg of naked germanium detectors installed in liquid nitrogen in GENIUS Test-Facility in GRAN-SASSO

    Energy Technology Data Exchange (ETDEWEB)

    Klapdor-Kleingrothaus, H.V. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

    2004-07-01

    The GENIUS Test Facility has come into operation in Gran Sasso on May 5, 2003 with its first ten kg of naked Ge detectors in liquid nitrogen. This is the first time that this novel technique for extreme background reduction in search for rare decays is applied under the background conditions of an underground laboratory. GENIUS-TF has the potential to check the DAMA evidence for cold dark matter by modulation, and possibly, to improve the accuracy of the recently observed first signal for neutrinoless double beta decay. (orig.)

  1. First 10 kg of naked germanium detectors installed in liquid nitrogen in GENIUS Test-Facility in GRAN-SASSO

    International Nuclear Information System (INIS)

    Klapdor-Kleingrothaus, H.V.

    2004-01-01

    The GENIUS Test Facility has come into operation in Gran Sasso on May 5, 2003 with its first ten kg of naked Ge detectors in liquid nitrogen. This is the first time that this novel technique for extreme background reduction in search for rare decays is applied under the background conditions of an underground laboratory. GENIUS-TF has the potential to check the DAMA evidence for cold dark matter by modulation, and possibly, to improve the accuracy of the recently observed first signal for neutrinoless double beta decay. (orig.)

  2. Determination of the germanium detector efficiency for measurements of the radionuclide activity contained in a radioactive waste drum

    International Nuclear Information System (INIS)

    Rodenas, J.; Gallardo, S.; Ballester, S.; Hoyler, F.

    2006-01-01

    One of the features in the characterization of a drum containing radioactive wastes is to verify the activity of radionuclides contained in the drum. An H.P. Ge detector can be used for this measurement. However, it is necessary to perform an efficiency calibration for all geometries involved. In the framework of a joint project between the Departamento de Ingenieria Quimica y Nuclear (Universidad Politecnica de Valencia, Spain) and the Fachbereich Angewandte Naturwissenschaften und Technik (Fachhochschule Aachen, Abteilung Julich, Germany), different configurations for a drum containing radioactive sources have been implemented in the laboratory. A cylindrical drum of 850 mm height, a diameter equal to 560 mm and 3 mm of steel thickness has been used in the experimental measurements. The drum contains a clay ceramic matrix whose chemical composition is 55% SiO 2 , 40% of Al 2 O 3 and 5% of TiO 2 . Several vertical PVC tubes having a diameter of 30 mm are inserted in the drum at different distances from the central axis. In the experiment, a pack of point sources with 133 Ba, 60 Co and 137 Cs is introduced into each one of the tubes. A ring-shape distributed source is generated by rotating the drum around its axis during the measurement. The detector efficiency is determined experimentally for these configurations. On the other hand, a Monte Carlo model, using the M.C.N.P. code, has been developed to simulate the drum, the clay matrix and the PVC tubes. The effect of the drum spinning has been reproduced simulating a ring source with different diameters. The model also includes detailed detector geometry. Using this Monte Carlo model, the detector efficiency is calculated for each configuration implemented in the laboratory. Comparison of results from Monte Carlo simulation and experimental measurements should permit the validation of the M.C.N.P. model. Consequently it will be possible to obtain efficiency curves without experimental measurements. Therefore, these

  3. Comparison of experimental pulse-height distributions in germanium detectors with integrated-tiger-series-code predictions

    International Nuclear Information System (INIS)

    Beutler, D.E.; Halbleib, J.A.; Knott, D.P.

    1989-01-01

    This paper reports pulse-height distributions in two different types of Ge detectors measured for a variety of medium-energy x-ray bremsstrahlung spectra. These measurements have been compared to predictions using the integrated tiger series (ITS) Monte Carlo electron/photon transport code. In general, the authors find excellent agreement between experiments and predictions using no free parameters. These results demonstrate that the ITS codes can predict the combined bremsstrahlung production and energy deposition with good precision (within measurement uncertainties). The one region of disagreement observed occurs for low-energy (<50 keV) photons using low-energy bremsstrahlung spectra. In this case the ITS codes appear to underestimate the produced and/or absorbed radiation by almost an order of magnitude

  4. Development of a 13-in. Hybrid Avalanche Photo-Detector (HAPD) for a next generation water Cherenkov detector

    International Nuclear Information System (INIS)

    Nakayama, H.; Kusaka, A.; Kakuno, H.; Abe, T.; Iwasaki, M.; Aihara, H.; Shiozawa, M.; Tanaka, M.; Kyushima, H.; Suyama, M.; Kawai, Y.

    2006-01-01

    We have developed a 13-in. Hybrid Avalanche Photo-Detector (HAPD) for photosensors in next generation water Cherenkov type detectors. We study the performance of the HAPD and the results show good time resolution better than σ=1ns, good sensitivity for single photon detection, wide dynamic range, and good uniformity on the photocathode. The HAPD is also expected to be less expensive than large PMTs because of its simpler structure without dynodes

  5. A new hybrid photomultiplier tube as detector for scintillating crystals

    International Nuclear Information System (INIS)

    De Notaristefani, F.; Vittori, F.; Puertolas, D.

    2002-01-01

    In this work, we have attentively studied the performance of a new hybrid photomultiplier tube (HPMT) as detector for photons from scintillating crystals. The HPMT is equipped with a YAP window in order to improve light collection and increase measured light response from scintillating crystals. Several measurements have been performed on BGO, LSO, CsI(Tl) and NaI(Tl) planar crystals having three different surface treatments as well as on YAP : Ce and CsI(Tl) matrices. Such crystals have been coupled to two HPMTs, one equipped with a YAP window (Y-HPMT) and the other with a conventional quartz window (Q-HPMT). Measurements on crystals coupled to the Y-HPMT have shown a consistent improvement of the light response, thanks to the presence of the YAP window. Indeed, the light response measured with the Y-HPMT was on average equal to 1.5, 2.1 and 2.6 times that obtained with the Q-HPMT for planar crystals with white painted (diffusive), fine ground and polished rear surfaces, respectively. With regards to crystal matrices, we measured a light response increase of about 1.2 times

  6. The exposure of the hybrid detector of the Pierre Auger Observatory

    OpenAIRE

    The Pierre Auger Collaboration

    2010-01-01

    Abstract The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays. It consists of a surface array to measure secondary particles at ground level and a fluorescence detector to measure the development of air showers in the atmosphere above the array. The ?hybrid? detection mode combines the information from the two subsystems. We describe the determination of the hybrid exposure for events observed by the fluorescence telescopes in coincidence with at least one w...

  7. Performance of hybrid photon detector prototypes with encapsulated silicon pixel detector and readout for the RICH counters of LHCb

    International Nuclear Information System (INIS)

    Campbell, M.; George, K.A.; Girone, M.; Gys, T.; Jolly, S.; Piedigrossi, D.; Riedler, P.; Rozema, P.; Snoeys, W.; Wyllie, K.

    2003-01-01

    These proceedings report on the performance of the latest prototype pixel hybrid photon detector in preparation for the LHCb Ring Imaging Cherenkov detectors. The prototype encapsulates a silicon pixel detector bump-bonded to a binary read-out chip with short (25 ns) peaking time and low ( - ) detection threshold. A brief description of the prototype is given, followed by the preliminary results of the characterisation of the prototype behaviour when tested using a low intensity pulsed light emitting diode. The results obtained are in good agreement with those obtained using previous prototypes. The proceedings conclude with a summary of the current status and future plans

  8. A Prototype RICH Detector Using Multi-Anode Photo Multiplier Tubes and Hybrid Photo-Diodes

    CERN Document Server

    Albrecht, E; Bibby, J H; Brook, N H; Doucas, G; Duane, A; Easo, S; Eklund, L; French, M; Gibson, V; Gys, Thierry; Halley, A W; Harnew, N; John, M; Piedigrossi, D; Rademacker, J; Simmons, B; Smale, N J; Teixeira-Dias, P; Toudup, L W; Websdale, David M; Wilkinson, G R; Wotton, S A

    2001-01-01

    The performance of a prototype Ring Imaging Cherenkov Detector is studied using a charged particle beam. The detector performance, using CF4 and air as radiators, is described. Cherenkov angle precision and photoelectron yield using hybrid photo-diodes and multi-anode PMTs agree with simulations and are assessed in terms of the requirements of the LHCb experiment.

  9. LHCb: Quantum Efficiency of Hybrid Photon Detectors for the LHCb RICH

    CERN Multimedia

    Lambert, Robert W

    2007-01-01

    The production of 550 hybrid photon detectors to be used within the LHCb RICH detectors has recently finished. Photonis-DEP have succeeded in consistently improving the tube quantum efficiency, by a relative 27,% with respect to preseries and prototype tubes, when integrated over the energy spectrum.

  10. Test-beam Results from a RICH Detector Prototype Using Aerogel Radiator and Pixel Hybrid Photon Detectors

    CERN Document Server

    Aglieri-Rinella, G; Van Lysebetten, A; Piedigrossi, D; Wyllie, K; Bellunato, T F; Calvi, M; Matteuzzi, C; Musy, M; Perego, D L; Somerville, L P; Newby, C; Easo, S; Wotton, S

    2006-01-01

    A test-beam study was performed at CERN with a Ring Imaging Cherenkov (RICH) prototype using three pixel Hybrid Photon Detectors. Results on the photon yield and Cherenkov angle resolution are presented here, for the Aerogel radiator and also for reference runs taken with Nitrogen radiator.

  11. The hybridized front end electronics of the Central Drift Chamber in the Stanford Linear Collider Detector

    International Nuclear Information System (INIS)

    Lo, C.C.; Kirsten, F.A.; Nakamura, M.

    1987-10-01

    In order to accommodate the high packaging density requirements for the front end electronics of the Central Drift Chamber (CDC) in the SLAC Linear Collider Detector (SLD), the CDC front end electronics has been hybridized. The hybrid package contains eight channels of amplifiers together with all the associated circuits for calibration, event recognition and power economy switching functions. A total of 1280 such hybrids are used in the CDC

  12. Liquid argon as active shielding and coolant for bare germanium detectors. A novel background suppression method for the GERDA 0νββ experiment

    International Nuclear Information System (INIS)

    Peiffer, J.P.

    2007-01-01

    Two of the most important open questions in particle physics are whether neutrinos are their own anti-particles (Majorana particles) as required by most extensions of the StandardModel and the absolute values of the neutrino masses. The neutrinoless double beta (0νββ) decay, which can be investigated using 76 Ge (a double beta isotope), is the most sensitive probe for these properties. There is a claim for an evidence for the 0νββ decay in the Heidelberg-Moscow (HdM) 76 Ge experiment by a part of the HdM collaboration. The new 76 Ge experiment Gerda aims to check this claim within one year with 15 kg.y of statistics in Phase I at a background level of ≤10 -2 events/(kg.keV.y) and to go to higher sensitivity with 100 kg.y of statistics in Phase II at a background level of ≤10 -3 events/(kg.keV.y). In Gerda bare germanium semiconductor detectors (enriched in 76 Ge) will be operated in liquid argon (LAr). LAr serves as cryogenic coolant and as high purity shielding against external background. To reach the background level for Phase II, new methods are required to suppress the cosmogenic background of the diodes. The background from cosmogenically produced 60 Co is expected to be ∝2.5.10 -3 events/(kg.keV.y). LAr scintillates in UV (λ=128 nm) and a novel concept is to use this scintillation light as anti-coincidence signal for background suppression. In this work the efficiency of such a LAr scintillation veto was investigated for the first time. In a setup with 19 kg active LAr mass a suppression of a factor 3 has been achieved for 60 Co and a factor 17 for 232 Th around Q ββ = 2039 keV. This suppression will further increase for a one ton active volume (factor O(100) for 232 Th and 60 Co). LAr scintillation can also be used as a powerful tool for background diagnostics. For this purpose a new, very stable and robust wavelength shifter/reflector combination for the light detection has been developed, leading to a photo electron (pe) yield of as much as

  13. Liquid argon as active shielding and coolant for bare germanium detectors. A novel background suppression method for the GERDA 0{nu}{beta}{beta} experiment

    Energy Technology Data Exchange (ETDEWEB)

    Peiffer, J.P.

    2007-07-25

    Two of the most important open questions in particle physics are whether neutrinos are their own anti-particles (Majorana particles) as required by most extensions of the StandardModel and the absolute values of the neutrino masses. The neutrinoless double beta (0{nu}{beta}{beta}) decay, which can be investigated using {sup 76}Ge (a double beta isotope), is the most sensitive probe for these properties. There is a claim for an evidence for the 0{nu}{beta}{beta} decay in the Heidelberg-Moscow (HdM) {sup 76}Ge experiment by a part of the HdM collaboration. The new {sup 76}Ge experiment Gerda aims to check this claim within one year with 15 kg.y of statistics in Phase I at a background level of {<=}10{sup -2} events/(kg.keV.y) and to go to higher sensitivity with 100 kg.y of statistics in Phase II at a background level of {<=}10{sup -3} events/(kg.keV.y). In Gerda bare germanium semiconductor detectors (enriched in {sup 76}Ge) will be operated in liquid argon (LAr). LAr serves as cryogenic coolant and as high purity shielding against external background. To reach the background level for Phase II, new methods are required to suppress the cosmogenic background of the diodes. The background from cosmogenically produced {sup 60}Co is expected to be {proportional_to}2.5.10{sup -3} events/(kg.keV.y). LAr scintillates in UV ({lambda}=128 nm) and a novel concept is to use this scintillation light as anti-coincidence signal for background suppression. In this work the efficiency of such a LAr scintillation veto was investigated for the first time. In a setup with 19 kg active LAr mass a suppression of a factor 3 has been achieved for {sup 60}Co and a factor 17 for {sup 232}Th around Q{sub {beta}}{sub {beta}} = 2039 keV. This suppression will further increase for a one ton active volume (factor O(100) for {sup 232}Th and {sup 60}Co). LAr scintillation can also be used as a powerful tool for background diagnostics. For this purpose a new, very stable and robust wavelength

  14. Manufacturing P-N junctions in germanium bodies

    International Nuclear Information System (INIS)

    Hall, R.N.

    1980-01-01

    A method of producing p-n junctions in Ge so as to facilitate their use as radiation detectors involves forming a body of high purity p-type germanium, diffusing lithium deep into the body, in the absence of electrolytic processes, to form a junction between n-type and p-type germanium greater than 1 mm depth. (UK)

  15. Status report on the International Germanium Experiment

    International Nuclear Information System (INIS)

    Brodzinski, R.L.; Hensley, W.K.; Miley, H.S.; Reeves, J.H.; Avignone, F.T.; Collar, J.I.; Guerard, C.K.; Courant, H.; Ruddick, K.; Kirpichnikov, I.V.; Starostin, A.S.; Osetrov, S.B.; Pomansky, A.A.; Smolnikov, A.A.; Vasiliev, S.I.

    1992-06-01

    Phase II detector fabrication for the International Germanium Experiment is awaiting resolution of technical details observed during Phase I. Measurements of fiducial volume, configuration of the tansistor-reset preamplifier stage, and sources of background are discussed. Cosmogenic 7 Be is measured in germanium. Radium contamination in electroformed copper reported. The 2ν double- beta decay half-life of 76 Ge measured with a Phase I detector is in reasonable agreement with previously reported values. No events are observed in the vicinity of the Oν double-beta decay energy

  16. Preliminary test of an imaging probe for nuclear medicine using hybrid pixel detectors

    International Nuclear Information System (INIS)

    Bertolucci, E.; Maiorino, M.; Mettivier, G.; Montesi, M.C.; Russo, P.

    2002-01-01

    We are investigating the feasibility of an intraoperative imaging probe for lymphoscintigraphy with Tc-99m tracer, for sentinel node radioguided surgery, using the Medipix series of hybrid detectors coupled to a collimator. These detectors are pixelated semiconductor detectors bump-bonded to the Medipix1 photon counting read-out chip (64x64 pixel, 170 μm pitch) or to the Medipix2 chip (256x256 pixel, 55 μm pitch), developed by the European Medipix collaboration. The pixel detector we plan to use in the final version of the probe is a semi-insulating GaAs detector or a 1-2 mm thick CdZnTe detector. For the preliminary tests presented here, we used 300-μm thick silicon detectors, hybridized via bump-bonding to the Medipix1 chip. We used a tungsten parallel-hole collimator (7 mm thick, matrix array of 64x64 100 μm circular holes with 170 μm pitch), and a 22, 60 and 122 keV point-like (1 mm diameter) radioactive sources, placed at various distances from the detector. These tests were conducted in order to investigate the general feasibility of this imaging probe and its resolving power. Measurements show the high resolution but low efficiency performance of the detector-collimator set, which is able to image the 122 keV source with <1 mm FWHM resolution

  17. Long-lived Hybrid Incore Detector for Core Monitoring and Protection

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Kyoon Ho [KEPCO Research Institute, Daejeon (Korea, Republic of)

    2010-10-15

    The signal production mechanism in a rhodium (Rh) fixed in-core detector emitter relies primarily on the beta particles resulting from neutron absorptions in either of two Rh isotopes to produce an electric current. As the neutron transmutation process depletes the Rh isotopes, the signal output per unit neutron flux from an Rh detector emitter will decrease. A vanadium detector is primarily sensitive to neutrons, but with a somewhat slower reaction time as that of a Rh detector. The benefit of vanadium over rhodium is its low depletion rate, which is a factor of 7 times less than that of rhodium. Platinum detectors are very sensitive to gamma flux, but only mildly sensitive to neutron flux. Because the depletion rate of platinum is very small, it can be neglected. Generally, both gamma and neutron signals are proportional to the assembly power. The characteristics of a new detector are the long life time due to the low depletion of emitter materials and the capability of reactor protection as well as reactor monitoring. The new detector uses vanadium and platinum as the emitter materials to meet the long life time and reactor protection capability. Vanadium detector is used for reactor monitoring and platinum detector is used for reactor protection. To determine the number of emitter strings, a comparative study of the power peaking factor monitoring accuracy for various self-powered fixed in-core detector geometries was made, and the configuration of the optimal detector design was also established and verified. The design of a new detector consists of five-string vanadium detector elements, and three-string platinum detector elements. The detector assembly also contains a background wire for compensation of noise signal and a thermocouple for use in the post-accident monitoring system. This new hybrid detector can be used for both reactor Monitoring And reactor Protection (MAP)

  18. Hybrid organic/inorganic position-sensitive detectors based on PEDOT:PSS/n-Si

    Science.gov (United States)

    Javadi, Mohammad; Gholami, Mahdiyeh; Torbatiyan, Hadis; Abdi, Yaser

    2018-03-01

    Various configurations like p-n junctions, metal-semiconductor Schottky barriers, and metal-oxide-semiconductor structures have been widely used in position-sensitive detectors. In this report, we propose a PEDOT:PSS/n-Si heterojunction as a hybrid organic/inorganic configuration for position-sensitive detectors. The influence of the thickness of the PEDOT:PSS layer, the wavelength of incident light, and the intensity of illumination on the device performance are investigated. The hybrid PSD exhibits very high sensitivity (>100 mV/mm), excellent nonlinearity (0.995) with a response time of heterojunction are very promising for developing a new class of position-sensitive detectors based on the hybrid organic/inorganic junctions.

  19. Research and Development Supporting a Next Generation Germanium Double Beta Decay Experiment

    Science.gov (United States)

    Rielage, Keith; Elliott, Steve; Chu, Pinghan; Goett, Johnny; Massarczyk, Ralph; Xu, Wenqin

    2015-10-01

    To improve the search for neutrinoless double beta decay, the next-generation experiments will increase in source mass and continue to reduce backgrounds in the region of interest. A promising technology for the next generation experiment is large arrays of Germanium p-type point contact detectors enriched in 76-Ge. The experience, expertise and lessons learned from the MAJORANA DEMONSTRATOR and GERDA experiments naturally lead to a number of research and development activities that will be useful in guiding a future experiment utilizing Germanium. We will discuss some R&D activities including a hybrid cryostat design, background reduction in cabling, connectors and electronics, and modifications to reduce assembly time. We acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program.

  20. Study of statistical properties of hybrid statistic in coherent multi-detector compact binary coalescences Search

    OpenAIRE

    Haris, K; Pai, Archana

    2015-01-01

    In this article, we revisit the problem of coherent multi-detector search of gravitational wave from compact binary coalescence with Neutron stars and Black Holes using advanced interferometers like LIGO-Virgo. Based on the loss of optimal multi-detector signal-to-noise ratio (SNR), we construct a hybrid statistic as a best of maximum-likelihood-ratio(MLR) statistic tuned for face-on and face-off binaries. The statistical properties of the hybrid statistic is studied. The performance of this ...

  1. Development of Hybrid and Monolithic Silicon Micropattern Detectors

    CERN Multimedia

    Beker, H; Snoeys, W; Campbell, M; Lemeilleur, F; Ropotar, I

    2002-01-01

    %RD-19 \\\\ \\\\ In a collaborative effort between particle physics institutes and microelectronics industry we are undertaking the development of true 2-dimensional semiconductor particle detectors with on-chip signal processing and information extraction: the so-called micropattern detector. This detector is able to cope in a robust way with high multiplicity events at high rates, while allowing for a longer detector lifetime under irradiation and a thinner sensitive depletion region. Therefore, it will be ideally suited for the complicated events in the LHC p-p collider experiments. Following a $^{\\prime}$stepping stone$^{\\prime}$ approach several telescopes of pixel planes, totalling now 600 cm$^{2}$ with \\(>\\)~1~M elements have been used in the WA97, NA50 and NA57 lead ion experiments. This new technology has facilitated the tracking considerably (see Fig.1). Not only Si but also GaAs and possibly diamond matrices can be connected to the readout matrix. Tests with GaAs pixel detectors with the RD-19 readout ...

  2. Prospects for hybrid pixel detectors in electron microscopy

    International Nuclear Information System (INIS)

    Faruqi, A.R.

    2001-01-01

    The current status of CCD-based detectors for cryo-electron microscopy of membrane and other proteins is described briefly, highlighting the strengths and weaknesses of the technique. Over the past few years CCD detectors have been used extensively in electron crystallography of membrane proteins, and in particular, in the study of the molecular transitions which take place during the photo-cycle of the light-driven proton pump bacteriorhodopsin. Direct-detection methods, which avoid the intermediate stages of converting the electron energy into light, offer the possibility of improved spatial resolution compared to CCD detectors; in addition, photon counting and noise-free readout should improve the signal-to-noise ratio

  3. Performance study of hybrid photon detectors for the LHCb RICH

    CERN Document Server

    Kanaya, N; Gys, Thierry; Piedigrossi, D; Wyllie, K

    2005-01-01

    The LHCb experiment is designed to study CP violation and rare phenomena of B mesons with very high accuracy. The LHCb RICH detectors are essential for positive kaon identification, and several strict demands are required of its photon detectors to achieve excellent particle identification performance. In particular, they should have good single photon sensitivity for visible and UV wavelengths and large coverage with fine granularity. HPDs have been developed to meet these requirements in collaboration with industry. They have now been chosen as the photon detector for LHCb, and pre-series tubes are under test prior to mass production. At the same time, more detailed studies are on-going to understand more deeply their characteristics. The result of various performance tests of these tubes as well as the fraction of light reflection in the HPD are described in this paper.

  4. Solution processable organic/inorganic hybrid ultraviolet photovoltaic detector

    Directory of Open Access Journals (Sweden)

    Xiaopeng Guo

    2016-05-01

    Full Text Available Ultraviolet (UV photodetector is a kind of important optoelectronic device which can be widely used in scientific and engineering fields including astronomical research, environmental monitoring, forest-fire prevention, medical analysis, and missile approach warning etc. The development of UV detector is hindered by the acquirement of stable p-type materials, which makes it difficult to realize large array, low-power consumption UV focal plane array (FPA detector. Here, we provide a novel structure (Al/Poly(9,9-di-n-octylfuorenyl-2,7-diyl(PFO/ZnO/ITO to demonstrate the UV photovoltaic (PV response. A rather smooth surface (RMS roughness: 0.28 nm may be reached by solution process, which sheds light on the development of large-array, light-weight and low-cost UV FPA detectors.

  5. Prototype of a hybrid cosmic ray detector at the Pico de Orizaba: First stage

    International Nuclear Information System (INIS)

    Ponce, E.; Perez, E.; Villasenor, L.; Garipov, G.; Salazar, H.; Martinez, O.; Moreno, E.; Pedraza, I.; Cotzomi, J.; Khrenov, B.

    2003-01-01

    In this work we present a progress report of the project of a high energy cosmic ray observatory located at Pico de Orizaba mountain. One of the goals of this facility will be to contribute to the understanding of the origin of the cosmic rays at energies around the feature known as the knee. To achieve this goal we plan to use a hybrid detector composed of a surface detector array and a fluorescence telescope. The design and expected performance of the fluorescent detector is presented

  6. Characterization and first experimental application of space-resolving, energy-dispersive germanium detectors for the precision spectroscopy on heavy ions; Charakterisierung und erster experimenteller Einsatz von ortsaufloesenden, energiedispersiven Germanium-Detektoren zur Praezisionsspektroskopie an schweren Ionen

    Energy Technology Data Exchange (ETDEWEB)

    Spillmann, Uwe

    2009-02-15

    First the actual status of the research for the 1s Lamb shift on heaviest systems as well as studies on the polarization of the radiative recombination radiation into the K shell of uranium are presented. On this base future precision experiments at storage rings are discussed. then follows a survey presentation of the GSI accelerator facility. Especially the experimental storage ring ESR is described, at which the experiments mentioned above were performed. Then an introduction to the fundamental understanding of the physical processes in the detection of X-radiation in semiconductor detectors is given. The following chapter discusses the detection technique of the Compton polarimetry and some experimental concepts for this. Then by means of a 4 x 4 pixel Ge(i) detector system, by which for the first time the K-REC radiation from uranium was measured at the ESR, an overview about the Monte-Carlo software EGS4 is given, which was applied to the efficiency correction in the evaluation phase and for the estimation of the detector behaviour during the planning phase of the new detectors. A presentation of the 1D and 2D microstrip detector system as well as the performed laboratory measurements follows. The results for the characterization of the 2D microstrip detector system at the synchrotron-radiation source ESRF in view of its application with the FOCAL spectrometer are thereafter described. The results of first test measurement on the Compton polarimetry, which were also performed at the ESRF, are then presented. Finally first experimental results, which wer obtained by the novel planar structured Ge(i) detectors, are shown.

  7. MSM-Metal Semiconductor Metal Photo-detector Using Black Silicon Germanium (SiGe) for Extended Wavelength Near Infrared Detection

    Science.gov (United States)

    2012-09-01

    its effect on the optical beam. Computer Tunable optical source Detectors Test MSM detector Lock-in- amplifier Multiplexer Transimpedance ... amplifier Three-way beam splitter L3 sample L1 Light source L4 L2 Reference Detector Reflectance Detector

  8. Extensive tests of Hybrid Photon Detectors (HPD) used to collect Cherenkov light

    International Nuclear Information System (INIS)

    Borsato, E.; Buccheri, A.; DalCorso, F.; Ferroni, F.; Iacovella, F.; Mazzoni, M.A.; Morandin, M.; Morganti, S.; Piredda, G.; Posocco, M.; Santacesaria, R.; Stroili, R.; Torassa, E.; Voci, C.

    1997-01-01

    The principle of operation of a newly developed proximity focused Hybrid Photon Detector is described. The HPD characteristics, performance and calibration are reported. Results from beam tests of aerogel threshold counters read out by HPD and the particle identification performance are presented. (orig.)

  9. A 'LEGO' Hybrid Photon Detector - assembled from standard mass-produced vacuum components

    International Nuclear Information System (INIS)

    Ferenc, Daniel; Lorenz, Eckart; Mirzoyan, Razmik

    2000-01-01

    Motivated primarily by the MAGIC atmospheric Cherenkov telescope project, we have developed a 'LEGO' Hybrid Photon Detector (HPD) comprising excellent focusing properties and protection against positive ion feedback. LEGO-HPD is supposed to be assembled from standard high vacuum components, which insures simplicity in the assembly procedure and reliability of operation

  10. Investigating the Inverse Square Law with the Timepix Hybrid Silicon Pixel Detector: A CERN [at] School Demonstration Experiment

    Science.gov (United States)

    Whyntie, T.; Parker, B.

    2013-01-01

    The Timepix hybrid silicon pixel detector has been used to investigate the inverse square law of radiation from a point source as a demonstration of the CERN [at] school detector kit capabilities. The experiment described uses a Timepix detector to detect the gamma rays emitted by an [superscript 241]Am radioactive source at a number of different…

  11. 2D dose distribution images of a hybrid low field MRI-γ detector

    Energy Technology Data Exchange (ETDEWEB)

    Abril, A., E-mail: ajabrilf@unal.edu.co; Agulles-Pedrós, L., E-mail: lagullesp@unal.edu.co [Medical Physics Group, Physics department, Universidad Nacional de Colombia, Bogotá (Colombia)

    2016-07-07

    The proposed hybrid system is a combination of a low field MRI and dosimetric gel as a γ detector. The readout system is based on the polymerization process induced by the gel radiation. A gel dose map is obtained which represents the functional part of hybrid image alongside with the anatomical MRI one. Both images should be taken while the patient with a radiopharmaceutical is located inside the MRI system with a gel detector matrix. A relevant aspect of this proposal is that the dosimetric gel has never been used to acquire medical images. The results presented show the interaction of the {sup 99m}Tc source with the dosimetric gel simulated in Geant4. The purpose was to obtain the planar γ 2D-image. The different source configurations are studied to explore the ability of the gel as radiation detector through the following parameters; resolution, shape definition and radio-pharmaceutical concentration.

  12. 2D dose distribution images of a hybrid low field MRI-γ detector

    International Nuclear Information System (INIS)

    Abril, A.; Agulles-Pedrós, L.

    2016-01-01

    The proposed hybrid system is a combination of a low field MRI and dosimetric gel as a γ detector. The readout system is based on the polymerization process induced by the gel radiation. A gel dose map is obtained which represents the functional part of hybrid image alongside with the anatomical MRI one. Both images should be taken while the patient with a radiopharmaceutical is located inside the MRI system with a gel detector matrix. A relevant aspect of this proposal is that the dosimetric gel has never been used to acquire medical images. The results presented show the interaction of the "9"9"mTc source with the dosimetric gel simulated in Geant4. The purpose was to obtain the planar γ 2D-image. The different source configurations are studied to explore the ability of the gel as radiation detector through the following parameters; resolution, shape definition and radio-pharmaceutical concentration.

  13. 2D dose distribution images of a hybrid low field MRI-γ detector

    Science.gov (United States)

    Abril, A.; Agulles-Pedrós, L.

    2016-07-01

    The proposed hybrid system is a combination of a low field MRI and dosimetric gel as a γ detector. The readout system is based on the polymerization process induced by the gel radiation. A gel dose map is obtained which represents the functional part of hybrid image alongside with the anatomical MRI one. Both images should be taken while the patient with a radiopharmaceutical is located inside the MRI system with a gel detector matrix. A relevant aspect of this proposal is that the dosimetric gel has never been used to acquire medical images. The results presented show the interaction of the 99mTc source with the dosimetric gel simulated in Geant4. The purpose was to obtain the planar γ 2D-image. The different source configurations are studied to explore the ability of the gel as radiation detector through the following parameters; resolution, shape definition and radio-pharmaceutical concentration.

  14. Characterization of hybrid self-powered neutron detector under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nakamichi, M. E-mail: masaru@oarai.jaeri.go.jp; Nagao, Y.; Yamamura, C.; Nakazawa, M.; Kawamura, H

    2000-11-01

    To evaluate the irradiation behaviour of a blanket mock-up on in-pile functional test, it is necessary to measure the neutron flux change in the in-pile mock-up by a neutron detector, such as the self-powered neutron detector (SPND). With its small-sized emitter, which has high sensitivity and fast response time, SPND is an indispensable tool in order to measure the local neutron flux change. In the case of an in-pile functional test, it is necessary that response time is less than 1s and ratio of SPND output current is more than 0.3 of output current of SPND with Rh emitter. Therefore, a hybrid SPND with high sensitivity and fast response time was developed. This hybrid SPND used a hybrid emitter, i.e. Co cladded Pt-13%R000.

  15. Characterization of hybrid self-powered neutron detector under neutron irradiation

    CERN Document Server

    Nakamichi, M; Yamamura, C; Nakazawa, M; Kawamura, H

    2000-01-01

    To evaluate the irradiation behaviour of a blanket mock-up on in-pile functional test, it is necessary to measure the neutron flux change in the in-pile mock-up by a neutron detector, such as the self-powered neutron detector (SPND). With its small-sized emitter, which has high sensitivity and fast response time, SPND is an indispensable tool in order to measure the local neutron flux change. In the case of an in-pile functional test, it is necessary that response time is less than 1s and ratio of SPND output current is more than 0.3 of output current of SPND with Rh emitter. Therefore, a hybrid SPND with high sensitivity and fast response time was developed. This hybrid SPND used a hybrid emitter, i.e. Co cladded Pt-13%Rh.

  16. Germanium junction detectors. Theoretical and practical factors governing their use in radiation spectrometry; Detecteurs a jonction au germanium. Elements theoriques et pratiques pour l'utilisation en spectrometrie de rayonnements

    Energy Technology Data Exchange (ETDEWEB)

    Hors, M; Philis, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    Semi-conductor detectors have recently greatly increased the possibilities available to nuclear spectroscopists for the study of {alpha}, {beta} and {gamma} radiations. Their use in radio-chemistry has encouraged us to study their principle, their mechanism and also the conditions under which they can be used. The first part, which is theoretical, consists of a summary of what should be known concerning the best use of junction detectors, in particular Ge (Li) detectors. The second part, which is experimental, summarizes the laboratory work carried out over a period of one year on Ge (Li) detectors. Stress is laid on the possibilities presented by the use of these detectors as photo-electric spectrometers, and also on the precautions required. Amongst the numerous results presented, the resolution of 2.52 keV obtained for the {gamma} radiation of 145.5 keV for {sup 141}Ce may be particularly noted. (authors) [French] Les detecteurs a semi-conducteurs ont recemment accru les possibilites offertes aux spectroscopistes nucleaires pour l'etude des radiations {alpha}, {beta}, {gamma}. Leurs utilisations en radiochimie nous ont incite a en etudier le principe, le mecanisme et d'autre part les conditions d'emploi. La premiere partie, theorique, rappelle l'essentiel de ce qu'il est utile de connaitre pour une utilisation optimale des detecteurs a jonctions et en particulier des detecteurs Ge (Li). La deuxieme partie, experimentale, resume les travaux realises au laboratoire pendant un an avec des detecteurs Ge (Li). Nous insistons sur les possibilites offertes et les precautions a prendre dans l'utilisation de ces detecteurs comme spectrometres photoelectriques. Parmi les nombreux resultats presentes, citons la resolution de 2,52 keV obtenue pour le rayonnement {gamma} de 145 f5 keV du {sup 141}Ce. (auteurs)

  17. Radiation Effects of n-type, Low Resistivity, Spiral Silicon Drift Detector Hybrid Systems

    International Nuclear Information System (INIS)

    Chen, W.; De Geronimo, G.; Carini, G.A.; Gaskin, J.A.; Keister, J.W.; Li, S.; Li, Z.; Ramsey, B.D.; Siddons, D.P.; Smith, G.C.; Verbitskaya, E.

    2011-01-01

    We have developed a new thin-window, n-type, low-resistivity, spiral silicon drift detector (SDD) array - to be used as an extraterrestrial X-ray spectrometer (in varying environments) for NASA. To achieve low-energy response, a thin SDD entrance window was produced using a previously developed method. These thin-window devices were also produced on lower resistivity, thinner, n-type, silicon material, effectively ensuring their radiation hardness in anticipation of operation in potentially harsh radiation environments (such as found around the Jupiter system). Using the Indiana University Cyclotron Facility beam line RERS1, we irradiated a set of suitable diodes up to 5 Mrad and the latest iteration of our ASICs up to 12 Mrad. Then we irradiated two hybrid detectors consisting of newly, such-produced in-house (BNL) SDD chips bonded with ASICs with doses of 0.25 Mrad and 1 Mrad. Also we irradiated another hybrid detector consisting of previously produced (by KETEK) on n-type, high-resistivity SDD chip bonded with BNL's ASICs with a dose of 1 Mrad. The measurement results of radiated diodes (up to 5 Mrad), ASICs (up to 12 Mrad) and hybrid detectors (up to 1 Mrad) are presented here.

  18. An overview of current developments in position-sensitive hybrid photon detectors and photo-multiplier tubes

    CERN Document Server

    Gys, Thierry

    1999-01-01

    Current developments in position-sensitive hybrid photon detectors and photo-multiplier tubes have stimulated increased interest from a variety of fields such as astronomy, biomedical imaging and high- energy physics. These devices are sensitive to single photons over a photon energy spectrum defined by the transmission of the optical entrance window and the photo-cathode type. Their spatial resolution ranges from a few millimeters for pad hybrid photon detectors and multi-anode photo-multiplier tubes down to a few tens of microns for pixel hybrid photon detectors and electron-bombarded charge-coupled devices. Basic technological and design aspects are assessed in this paper. (21 refs).

  19. Evaluation of a hybrid photon counting pixel detector for X-ray polarimetry

    International Nuclear Information System (INIS)

    Michel, T.; Durst, J.

    2008-01-01

    It has already been shown in literature that X-ray sensitive CCDs can be used to measure the degree of linear polarization of X-rays using the effect that photoelectrons are emitted with a non-isotropic angular distribution in respect to the orientation of the electric field vector of impinging photons. Up to now hybrid semiconductor pixel detectors like the Timepix-detector have never been used for X-ray polarimetry. The main reason for this is that the pixel pitch is large compared to CCDs which results in a much smaller analyzing power. On the other hand, the active thickness of the sensor layer can be larger than in CCDs leading to an increased efficiency. Therefore hybrid photon counting pixel detectors may be used for imaging and polarimetry at higher photon energies. For irradiation with polarized X-ray photons we were able to measure an asymmetry between vertical and horizontal double hit events in neighboring pixels of the hybrid photon counting Timepix-detector at room temperature. For the specific spectrum used in our experiment an average polarization asymmetry of (0.96±0.02)% was measured. Additionally, the Timepix-detector with its spectroscopic time-over-threshold-mode was used to measure the dependence of the polarization asymmetry on energy deposition in the detector. Polarization asymmetries between 0.2% at 29 keV and 3.4% at 78 keV energy deposition were determined. The results can be reproduced with our EGS4-based Monte-Carlo simulation

  20. X-ray Imaging Using a Hybrid Photon Counting GaAs Pixel Detector

    CERN Document Server

    Schwarz, C; Göppert, R; Heijne, Erik H M; Ludwig, J; Meddeler, G; Mikulec, B; Pernigotti, E; Rogalla, M; Runge, K; Smith, K M; Snoeys, W; Söldner-Rembold, S; Watt, J

    1999-01-01

    The performance of hybrid GaAs pixel detectors as X-ray imaging sensors were investigated at room temperature. These hybrids consist of 300 mu-m thick GaAs pixel detectors, flip-chip bonded to a CMOS Single Photon Counting Chip (PCC). This chip consists of a matrix of 64 x 64 identical square pixels (170 mu-m x 170 mu-m) and covers a total area of 1.2 cm**2. The electronics in each cell comprises a preamplifier, a discriminator with a 3-bit threshold adjust and a 15-bit counter. The detector is realized by an array of Schottky diodes processed on semi-insulating LEC-GaAs bulk material. An IV-charcteristic and a detector bias voltage scan showed that the detector can be operated with voltages around 200 V. Images of various objects were taken by using a standard X-ray tube for dental diagnostics. The signal to noise ratio (SNR) was also determined. The applications of these imaging systems range from medical applications like digital mammography or dental X-ray diagnostics to non destructive material testing (...

  1. Neutrino Interactions in a Hybrid Emulsion - Bubble Chamber Detector

    Energy Technology Data Exchange (ETDEWEB)

    Rosenbladt, Robert Ludwig [Univ. of Washington, Seattle, WA (United States)

    1981-05-01

    target consisting of 22 - 1 liter stacks of cryogenically sensitive nuclear emulsion has been exposed inside the 15 Foot Bubble Chamber to the Fermilab wide-band neutrino beam. A hybrid system of emulsion plus bubble chamber was used to find and analyze neutrino interactions with nuclei in the emulsion target. The average multiplicity of charged minimum ionization tracks of the 45 events was found to be 6.8 ± 0.5. The normalized multiplicity with respect to neutrino - proton interactions at the same average hadronic center of mass energy was found to be 1.3 ± 0.2. When compared to neutrino - proton interactions, the rapidity distribution shows a clear signal for intranuclear cascading in the target fragmentation region. Measured rapidity and multiplicity distributions are compared with predictions of the Growth of Longitudinal Distances Model of Nikolaev and the Coherent Tube Model.

  2. The high-voltage system for the LHCb RICH hybrid photon detectors

    International Nuclear Information System (INIS)

    Arnaboldi, C.; Bellunato, T.; De Lucia, A.; Fanchini, E.; Perego, D.L.; Pessina, G.

    2009-01-01

    We describe the characterization of the high-voltage (HV) distribution system designed and produced for the pixel hybrid photon detectors of the ring imaging Cherenkov counters of the LHCb experiment. The HV system consists of a series of printed circuit boards with a specific layout designed to prevent any discharge arising from high electric fields. The system has dedicated monitoring and control features to supervise HV set-up during data taking. The full production of the HV system has been now completed and all the boards have been fully characterized and installed in the detector, which is currently being commissioned.

  3. Performance Studies of Pixel Hybrid Photon Detectors for the LHCb RICH Counters

    CERN Document Server

    Aglieri Rinella, G; Piedigrossi, D; Van Lysebetten, A

    2004-01-01

    The Pixel Hybrid Photon Detector is a vacuum tube with a multi-alkali photo cathode, high voltage cross-focused electron optics and an anode consisting of a silicon pixel detector bump-bonded to a readout CMOS electronic chip fully encapsulated in the device. The Pixel HPD fulfils the requirements of the Ring Imaging Cherenkov counters of the LHCb experiment at LHC. The performances of the Pixel HPD will be discussed with reference to laboratory measurements, Cherenkov light imaging in recent beam tests, image distortions due to a magnetic field.

  4. Hybrid metal organic scintillator materials system and particle detector

    Science.gov (United States)

    Bauer, Christina A.; Allendorf, Mark D.; Doty, F. Patrick; Simmons, Blake A.

    2011-07-26

    We describe the preparation and characterization of two zinc hybrid luminescent structures based on the flexible and emissive linker molecule, trans-(4-R,4'-R') stilbene, where R and R' are mono- or poly-coordinating groups, which retain their luminescence within these solid materials. For example, reaction of trans-4,4'-stilbenedicarboxylic acid and zinc nitrate in the solvent dimethylformamide (DMF) yielded a dense 2-D network featuring zinc in both octahedral and tetrahedral coordination environments connected by trans-stilbene links. Similar reaction in diethylformamide (DEF) at higher temperatures resulted in a porous, 3-D framework structure consisting of two interpenetrating cubic lattices, each featuring basic to zinc carboxylate vertices joined by trans-stilbene, analogous to the isoreticular MOF (IRMOF) series. We demonstrate that the optical properties of both embodiments correlate directly with the local ligand environments observed in the crystal structures. We further demonstrate that these materials produce high luminescent response to proton radiation and high radiation tolerance relative to prior scintillators. These features can be used to create sophisticated scintillating detection sensors.

  5. Development of hybrid track detector using CR39 and photographic plate

    International Nuclear Information System (INIS)

    Kuge, K.; Endo, Y.; Hayashi, K.; Iwakiri, S.; Hasegawa, A.; Yasuda, N.; Kumagai, H.

    2005-01-01

    To improve the hybrid track detector using both CR39 and silver halide photography the gold deposition development technique was applied to this. Nuclear tracks composed of gold clusters were obtained. This method has several advantages; 1. no filament formation, 2. easy control of the cluster size owing to the independence of the size of silver halide grain, 3. easy treatment of the waste solution of developer. (author)

  6. Development of hybrid track detector using CR39 and photographic plate

    International Nuclear Information System (INIS)

    Kuge, Kenichi; Endo, Yusuke; Hayashi, Kentaro; Hasegawa, Akira; Kumagai, Hiroshi

    2004-01-01

    Hybrid track detector using CR39 and color photography was prepared by coating multi-layered color photographic emulsions on one side of CR39. Etch pits and color tracks were observed at the same time. Photographic plate with different sensitivity emulsions and couplers were exposed to light, α-, β- and γ-rays. We observed sensitivity difference to the radiation by color changes on one plate. (authors)

  7. One dimensional spatial resolution optimization on a hybrid low field MRI-gamma detector

    Energy Technology Data Exchange (ETDEWEB)

    Agulles-Pedrós, L., E-mail: lagullesp@unal.edu.co; Abril, A., E-mail: ajabrilf@unal.edu.co [Medical Physics Group, Physics Department, Universidad Nacional de Colombia, Bogotá (Colombia)

    2016-07-07

    Hybrid systems like Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) and MRI/gamma camera, offer advantages combining the resolution and contrast capability of MRI with the better contrast and functional information of nuclear medicine techniques. However, the radiation detectors are expensive and need an electronic set-up, which can interfere with the MRI acquisition process or viceversa. In order to improve these drawbacks, in this work it is presented the design of a low field NMR system made up of permanent magnets compatible with a gamma radiation detector based on gel dosimetry. The design is performed using the software FEMM for estimation of the magnetic field, and GEANT4 for the physical process involved in radiation detection and effect of magnetic field. The homogeneity in magnetic field is achieved with an array of NbFeB magnets in a linear configuration with a separation between the magnets, minimizing the effect of Compton back scattering compared with a no-spacing linear configuration. The final magnetic field in the homogeneous zone is ca. 100 mT. In this hybrid proposal, although the gel detector do not have spatial resolution per se, it is possible to obtain a dose profile (1D image) as a function of the position by using a collimator array. As a result, the gamma detector system described allows a complete integrated radiation detector within the low field NMR (lfNMR) system. Finally we present the better configuration for the hybrid system considering the collimator parameters such as height, thickness and distance.

  8. Characterisation of the NA62 GigaTracker End of Column Demonstrator Hybrid Pixel Detector

    Science.gov (United States)

    Noy, M.; Aglieri Rinella, G.; Cotta Ramusino, A.; Fiorini, M.; Jarron, P.; Kaplon, J.; Kluge, A.; Martin, E.; Morel, M.; Perktold, L.; Poltorak, K.; Riedler, P.

    2011-11-01

    The architecture and characterisation of the NA62 GigaTracker End of Column Demonstrator Hybrid Pixel Detector (HPD) are presented. This detector must perform time stamping to 200 ps (RMS) or better, provide 300 μm pitch position information and operate with a dead time of 1% or less for 800 MHz-1 GHz beam rate. The demonstrator HPD Assembly comprises a readout chip with a test column of 45 pixels, alongside other test structures, bump bonded to a p-in-n detector 200 μm in thickness. Validation of the performance of the HPD and the time-over-threshold timewalk compensation mechanism with both beam particles and a high precision laser system was performed and is presented. Confirmation of better than the required time stamping precision has been demonstrated and subsequent work on the design of the full-scale ASIC, dubbed TDCPix, is underway. An overview of the TDCPix architecure is given.

  9. Low mass hybrid pixel detectors for the high luminosity LHC upgrade

    CERN Document Server

    Gonella, Laura; Desch, Klaus

    2013-11-11

    Reducing material in silicon trackers is of major importance for a good overall detector performance, and poses severe challenges to the design of the tracking system. To match the low mass constraints for trackers in High Energy Physics experiments at high luminosity, dedicated technological developments are required. This dissertation presents three technologies to design low mass hybrid pixel detectors for the high luminosity upgrades of the LHC. The work targets specifically the reduction of the material from the detector services and modules, with novel powering schemes, flip chip and interconnection technologies. A serial powering scheme is prototyped, featuring a new regulator concept, a control and protection element, and AC-coupled data transmission. A modified flip chip technology is developed for thin, large area Front-End chips, and a via last Through Silicon Via process is demonstrated on existing pixel modules. These technologies, their developments, and the achievable material reduction are dis...

  10. The germination of germanium

    Science.gov (United States)

    Burdette, Shawn C.; Thornton, Brett F.

    2018-02-01

    Shawn C. Burdette and Brett F. Thornton explore how germanium developed from a missing element in Mendeleev's periodic table to an enabler for the information age, while retaining a nomenclature oddity.

  11. A new PET detector concept for compact preclinical high-resolution hybrid MR-PET

    Science.gov (United States)

    Berneking, Arne; Gola, Alberto; Ferri, Alessandro; Finster, Felix; Rucatti, Daniele; Paternoster, Giovanni; Jon Shah, N.; Piemonte, Claudio; Lerche, Christoph

    2018-04-01

    This work presents a new PET detector concept for compact preclinical hybrid MR-PET. The detector concept is based on Linearly-Graded SiPM produced with current FBK RGB-HD technology. One 7.75 mm x 7.75 mm large sensor chip is coupled with optical grease to a black coated 8 mm x 8 mm large and 3 mm thick monolithic LYSO crystal. The readout is obtained from four readout channels with the linear encoding based on integrated resistors and the Center of Gravity approach. To characterize the new detector concept, the spatial and energy resolutions were measured. Therefore, the measurement setup was prepared to radiate a collimated beam to 25 different points perpendicular to the monolithic scintillator crystal. Starting in the center point of the crystal at 0 mm / 0 mm and sampling a grid with a pitch of 1.75 mm, all significant points of the detector were covered by the collimator beam. The measured intrinsic spatial resolution (FWHM) was 0.74 +/- 0.01 mm in x- and 0.69 +/- 0.01 mm in the y-direction at the center of the detector. At the same point, the measured energy resolution (FWHM) was 13.01 +/- 0.05 %. The mean intrinsic spatial resolution (FWHM) over the whole detector was 0.80 +/- 0.28 mm in x- and 0.72 +/- 0.19 mm in y-direction. The energy resolution (FWHM) of the detector was between 13 and 17.3 % with an average energy resolution of 15.7 +/- 1.0 %. Due to the reduced thickness, the sensitivity of this gamma detector is low but still higher than pixelated designs with the same thickness due to the monolithic crystals. Combining compact design, high spatial resolution, and high sensitivity, the detector concept is particularly suitable for applications where the scanner bore size is limited and high resolution is required - as is the case in small animal hybrid MR-PET.

  12. 3D track reconstruction capability of a silicon hybrid active pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    Bergmann, Benedikt; Pichotka, Martin; Pospisil, Stanislav; Vycpalek, Jiri [Czech Technical University in Prague, Institute of Experimental and Applied Physics, Praha (Czech Republic); Burian, Petr; Broulim, Pavel [Czech Technical University in Prague, Institute of Experimental and Applied Physics, Praha (Czech Republic); University of West Bohemia, Faculty of Electrical Engineering, Pilsen (Czech Republic); Jakubek, Jan [Advacam s.r.o., Praha (Czech Republic)

    2017-06-15

    Timepix3 detectors are the latest generation of hybrid active pixel detectors of the Medipix/Timepix family. Such detectors consist of an active sensor layer which is connected to the readout ASIC (application specific integrated circuit), segmenting the detector into a square matrix of 256 x 256 pixels (pixel pitch 55 μm). Particles interacting in the active sensor material create charge carriers, which drift towards the pixelated electrode, where they are collected. In each pixel, the time of the interaction (time resolution 1.56 ns) and the amount of created charge carriers are measured. Such a device was employed in an experiment in a 120 GeV/c pion beam. It is demonstrated, how the drift time information can be used for ''4D'' particle tracking, with the three spatial dimensions and the energy losses along the particle trajectory (dE/dx). Since the coordinates in the detector plane are given by the pixelation (x,y), the x- and y-resolution is determined by the pixel pitch (55 μm). A z-resolution of 50.4 μm could be achieved (for a 500 μm thick silicon sensor at 130 V bias), whereby the drift time model independent z-resolution was found to be 28.5 μm. (orig.)

  13. 3D track reconstruction capability of a silicon hybrid active pixel detector

    Science.gov (United States)

    Bergmann, Benedikt; Pichotka, Martin; Pospisil, Stanislav; Vycpalek, Jiri; Burian, Petr; Broulim, Pavel; Jakubek, Jan

    2017-06-01

    Timepix3 detectors are the latest generation of hybrid active pixel detectors of the Medipix/Timepix family. Such detectors consist of an active sensor layer which is connected to the readout ASIC (application specific integrated circuit), segmenting the detector into a square matrix of 256 × 256 pixels (pixel pitch 55 μm). Particles interacting in the active sensor material create charge carriers, which drift towards the pixelated electrode, where they are collected. In each pixel, the time of the interaction (time resolution 1.56 ns) and the amount of created charge carriers are measured. Such a device was employed in an experiment in a 120 GeV/c pion beam. It is demonstrated, how the drift time information can be used for "4D" particle tracking, with the three spatial dimensions and the energy losses along the particle trajectory (dE/dx). Since the coordinates in the detector plane are given by the pixelation ( x, y), the x- and y-resolution is determined by the pixel pitch (55 μm). A z-resolution of 50.4 μm could be achieved (for a 500 μm thick silicon sensor at 130 V bias), whereby the drift time model independent z-resolution was found to be 28.5 μm.

  14. Characterization and first experimental application of space-resolving, energy-dispersive germanium detectors for the precision spectroscopy on heavy ions

    International Nuclear Information System (INIS)

    Spillmann, Uwe

    2009-02-01

    First the actual status of the research for the 1s Lamb shift on heaviest systems as well as studies on the polarization of the radiative recombination radiation into the K shell of uranium are presented. On this base future precision experiments at storage rings are discussed. then follows a survey presentation of the GSI accelerator facility. Especially the experimental storage ring ESR is described, at which the experiments mentioned above were performed. Then an introduction to the fundamental understanding of the physical processes in the detection of X-radiation in semiconductor detectors is given. The following chapter discusses the detection technique of the Compton polarimetry and some experimental concepts for this. Then by means of a 4 x 4 pixel Ge(i) detector system, by which for the first time the K-REC radiation from uranium was measured at the ESR, an overview about the Monte-Carlo software EGS4 is given, which was applied to the efficiency correction in the evaluation phase and for the estimation of the detector behaviour during the planning phase of the new detectors. A presentation of the 1D and 2D microstrip detector system as well as the performed laboratory measurements follows. The results for the characterization of the 2D microstrip detector system at the synchrotron-radiation source ESRF in view of its application with the FOCAL spectrometer are thereafter described. The results of first test measurement on the Compton polarimetry, which were also performed at the ESRF, are then presented. Finally first experimental results, which wer obtained by the novel planar structured Ge(i) detectors, are shown

  15. The large-area hybrid-optics CLAS12 RICH detector: Tests of innovative components

    International Nuclear Information System (INIS)

    Contalbrigo, M.; Baltzell, N.; Benmokhtar, F.; Barion, L.; Cisbani, E.; El Alaoui, A.; Hafidi, K.; Hoek, M.; Kubarovsky, V.; Lagamba, L.; Lucherini, V.; Malaguti, R.; Mirazita, M.; Montgomery, R.; Movsisyan, A.; Musico, P.; Orecchini, D.; Orlandi, A.; Pappalardo, L.L.; Pereira, S.

    2014-01-01

    A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Lab to study the 3D nucleon structure in the yet poorly explored valence region by deep-inelastic scattering, and to perform precision measurements in hadronization and hadron spectroscopy. The adopted solution foresees a novel hybrid optics design based on an aerogel radiator, composite mirrors and densely packed and highly segmented photon detectors. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). The preliminary results of individual detector component tests and of the prototype performance at test-beams are reported here. - Highlights: • A novel hybrid-optics configuration was proven to work with a large RICH prototype. • Innovative RICH components were studied both in laboratory tests and test-beams. • Aerogel of large Rayleigh scattering length at n=1.05 was characterized. • Novel vs commercially available multi-anode photomultipliers were compared. • The response of SiPM matrices to Cherenkov light was tested at various temperatures

  16. The large-area hybrid-optics CLAS12 RICH detector: Tests of innovative components

    Energy Technology Data Exchange (ETDEWEB)

    Contalbrigo, M., E-mail: contalbrigo@fe.infn.it [INFN Sezione di Ferrara and University of Ferrara (Italy); Baltzell, N. [Argonne National Laboratory, IL (United States); Benmokhtar, F. [Christopher Newport University, VA (United States); Duquesne University, PA (United States); Barion, L. [INFN Sezione di Ferrara and University of Ferrara (Italy); Cisbani, E. [INFN Sezione di Roma – Gruppo Collega to Sanità (Italy); Italian National Institute of Health (Italy); El Alaoui, A. [Universidad Tecnica Federico Santa Maria, Valparaiso (Chile); Argonne National Laboratory, IL (United States); Hafidi, K. [Argonne National Laboratory, IL (United States); Hoek, M. [Glasgow University (United Kingdom); J. Gutenberg Universität, Mainz (Germany); Kubarovsky, V. [Thomas Jefferson National Laboratory, VA (United States); Lagamba, L. [INFN Sezione di Bari, University of Bari (Italy); Lucherini, V. [INFN Laboratori Nazionali di Frascati (Italy); Malaguti, R. [INFN Sezione di Ferrara and University of Ferrara (Italy); Mirazita, M. [INFN Laboratori Nazionali di Frascati (Italy); Montgomery, R. [Glasgow University (United Kingdom); INFN Laboratori Nazionali di Frascati (Italy); Movsisyan, A. [INFN Sezione di Ferrara and University of Ferrara (Italy); Musico, P. [INFN Sezione di Genova (Italy); Orecchini, D.; Orlandi, A. [INFN Laboratori Nazionali di Frascati (Italy); Pappalardo, L.L. [INFN Sezione di Ferrara and University of Ferrara (Italy); Pereira, S. [INFN Laboratori Nazionali di Frascati (Italy); and others

    2014-12-01

    A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Lab to study the 3D nucleon structure in the yet poorly explored valence region by deep-inelastic scattering, and to perform precision measurements in hadronization and hadron spectroscopy. The adopted solution foresees a novel hybrid optics design based on an aerogel radiator, composite mirrors and densely packed and highly segmented photon detectors. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). The preliminary results of individual detector component tests and of the prototype performance at test-beams are reported here. - Highlights: • A novel hybrid-optics configuration was proven to work with a large RICH prototype. • Innovative RICH components were studied both in laboratory tests and test-beams. • Aerogel of large Rayleigh scattering length at n=1.05 was characterized. • Novel vs commercially available multi-anode photomultipliers were compared. • The response of SiPM matrices to Cherenkov light was tested at various temperatures.

  17. Precipitation of lithium in germanium

    International Nuclear Information System (INIS)

    Masaik, M.; Furgolle, B.

    1969-01-01

    The precipitation of Lithium in Germanium was studied. Taking account of the interactions Ga LI, LiO, we calculated the oxygen content in germanium samples from the resistivity measurements. (authors)

  18. An X-ray scanner prototype based on a novel hybrid gaseous detector

    CERN Document Server

    Iacobaeus, C; Lund-Jensen, B; Peskov, Vladimir

    2007-01-01

    We have developed a prototype of a new type of hybrid X-ray detector. It contains a thin wall (few μm) edge- illuminated lead glass capillary plate (acting as a converter of X-rays photons to primary electrons) combined with a microgap parallel-plate avalanche chamber operating in various gas mixtures at 1 atm. The operation of these converters was studied in a wide range of X-ray energies (from 6 to 60 keV) at incident angles varying from 0° to 90°. The detection efficiency, depending on the geometry, photon's energy, incident angle and the mode of operation, was between a few and 40%. The position resolution achieved was 50 μm in digital form and was practically independent of the photon's energy or gas mixture. The developed detector may open new possibilities for medical imaging, for example in mammography, portal imaging, radiography (including security devices), crystallography and many other applications.

  19. TSV last for hybrid pixel detectors: Application to particle physics and imaging experiments

    CERN Document Server

    Henry, D; Berthelot, A; Cuchet, R; Chantre, C; Campbell, M

    Hybrid pixel detectors are now widely used in particle physics experiments and at synchrotron light sources. They have also stimulated growing interest in other fields and, in particular, in medical imaging. Through the continuous pursuit of miniaturization in CMOS it has been possible to increase the functionality per pixel while maintaining or even shrinking pixel dimensions. The main constraint on the more extensive use of the technology in all fields is the cost of module building and the difficulty of covering large areas seamlessly [1]. On another hand, in the field of electronic component integration, a new approach has been developed in the last years, called 3D Integration. This concept, based on using the vertical axis for component integration, allows improving the global performance of complex systems. Thanks to this technology, the cost and the form factor of components could be decreased and the performance of the global system could be enhanced. In the field of radiation imaging detectors the a...

  20. Nuclear Characteristics of SPNDs and Preliminary Calculation of Hybrid Fixed Incore Detector with Monte Carlo Code

    International Nuclear Information System (INIS)

    Koo, Bon Seung; Lee, Kyung Hoon; Song, Jae Seung; Park, Sang Yoon

    2013-01-01

    In this paper, the basic nuclear characteristics of major emitter materials were surveyed. In addition, preliminary calculations of Cobalt-Vanadium fixed incore detector were performed using the Monte Carlo code. Calculational results were cross-checked by KARMA. KARMA is a two-dimensional multigroup transport theory code developed by the KAERI and approved by Korean regularity agency to be employed as a nuclear design tool for a Korean commercial pressurizer water reactor. The nuclear characteristics of the major emitter materials were surveyed, and preliminary calculations of the hybrid fixed incore detector were performed with the MCNP code. The eigenvalue and pin-by-pin fission power distributions were calculated and showed good agreement with the KARMA calculation results. As future work, gamma power distributions as well as several types of XS of the emitter, insulator, and collector regions for a Co-V ICI assembly will be evaluated and compared

  1. Hybrid Detector for the Measurement of Properties of Secondary Cosmic Rays

    International Nuclear Information System (INIS)

    Chavez, N.; Pasaye, E.; Salazar, H.; Villasenor, L.

    2003-01-01

    We report on the measurement of the lifetimes of pions, kaons and muons in the secondary cosmic-ray radiation by using a hybrid detector. The detector consists of a container filled with liquid scintillator that produces scintillation light when crossed by charged particles; this container is located atop a water tank that produces Cherenkov light when crossed by charged particles. Both containers have one phototube inside to detect the light produced. The electronics used consists of NIM modules, two digital oscilloscopes and one PC. This equipment is multipurpose and can be conventionally found in any modern physics laboratory. The results obtained for the muon, pion and kaon lifetimes are the following: τμ =2.120±0.02 μs, τπ =24.63±3 ns y τK = 12.52±2 ns in good agreement with the literature

  2. Low mass hybrid pixel detectors for the high luminosity LHC upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Gonella, Laura

    2013-10-15

    Reducing material in silicon trackers is of major importance for a good overall detector performance, and poses severe challenges to the design of the tracking system. To match the low mass constraints for trackers in High Energy Physics experiments at high luminosity, dedicated technological developments are required. This dissertation presents three technologies to design low mass hybrid pixel detectors for the high luminosity upgrades of the LHC. The work targets specifically the reduction of the material from the detector services and modules, with novel powering schemes, flip chip and interconnection technologies. A serial powering scheme is prototyped, featuring a new regulator concept, a control and protection element, and AC-coupled data transmission. A modified flip chip technology is developed for thin, large area Front-End chips, and a via last Through Silicon Via process is demonstrated on existing pixel modules. These technologies, their developments, and the achievable material reduction are discussed using the upgrades of the ATLAS pixel detector as a case study.

  3. Low mass hybrid pixel detectors for the high luminosity LHC upgrade

    International Nuclear Information System (INIS)

    Gonella, Laura

    2013-10-01

    Reducing material in silicon trackers is of major importance for a good overall detector performance, and poses severe challenges to the design of the tracking system. To match the low mass constraints for trackers in High Energy Physics experiments at high luminosity, dedicated technological developments are required. This dissertation presents three technologies to design low mass hybrid pixel detectors for the high luminosity upgrades of the LHC. The work targets specifically the reduction of the material from the detector services and modules, with novel powering schemes, flip chip and interconnection technologies. A serial powering scheme is prototyped, featuring a new regulator concept, a control and protection element, and AC-coupled data transmission. A modified flip chip technology is developed for thin, large area Front-End chips, and a via last Through Silicon Via process is demonstrated on existing pixel modules. These technologies, their developments, and the achievable material reduction are discussed using the upgrades of the ATLAS pixel detector as a case study.

  4. Characterization of an x-ray hybrid CMOS detector with low interpixel capacitive crosstalk

    OpenAIRE

    Griffith, Christopher V.; Bongiorno, Stephen D.; Burrows, David N.; Falcone, Abraham D.; Prieskorn, Zachary R.

    2012-01-01

    We present the results of x-ray measurements on a hybrid CMOS detector that uses a H2RG ROIC and a unique bonding structure. The silicon absorber array has a 36{\\mu}m pixel size, and the readout array has a pitch of 18{\\mu}m; but only one readout circuit line is bonded to each 36x36{\\mu}m absorber pixel. This unique bonding structure gives the readout an effective pitch of 36{\\mu}m. We find the increased pitch between readout bonds significantly reduces the interpixel capacitance of the CMOS ...

  5. Quality Assurance of Pixel Hybrid Photon Detectors for the LHCb Ring Imaging Cherenkov Counters

    CERN Document Server

    Carson, Laurence

    Pion/kaon discrimination in the LHCb experiment will be provided by two Ring Imaging Cherenkov (RICH) counters. These use arrays of 484 Hybrid Photon Detectors (HPDs) to detect the Cherenkov photons emitted by charged particles traversing the RICH. The results from comprehensive quality assurance tests on the 550 HPDs manufactured for LHCb are described. Leakage currents, dead channel probabilities, dark count rates and ion feedback rates are reported. Furthermore, measurements carried out on a sample of tubes to determine the efficiency of the HPD pixel chip by measuring the summed analogue response from the backplane of the silicon sensor are described.

  6. Mesostructured metal germanium sulfides

    Energy Technology Data Exchange (ETDEWEB)

    MacLachlan, M.J.; Coombs, N.; Bedard, R.L.; White, S.; Thompson, L.K.; Ozin, G.A.

    1999-12-29

    A new class of mesostructured metal germanium sulfide materials has been prepared and characterized. The synthesis, via supramolecular assembly of well-defined germanium sulfide anionic cluster precursors and transition-metal cations in formamide, represents a new strategy for the formation of this class of solids. A variety of techniques were employed to examine the structure and composition of the materials. Structurally, the material is best described as a periodic mesostructured metal sulfide-based coordination framework akin to periodic hexagonal mesoporous silica, MCM-41. At the molecular scale, the materials strongly resemble microstructured metal germanium sulfides, in which the structure of the [Ge{sub 4}S{sub 10}]{sup 4{minus}} cluster building-blocks are intact and linked via {mu}-S-M-S bonds. Evidence for a metal-metal bond in mesostructured Cu/Ge{sub 4}S{sub 10} is also provided.

  7. Detection of secondary electrons with pixelated hybrid semiconductor detectors; Sekundaerelektronennachweis mit pixelierten hybriden Halbleiterdetektoren

    Energy Technology Data Exchange (ETDEWEB)

    Gebert, Ulrike Sonja

    2011-09-14

    Within the scope of this thesis, secondary electrons were detected with a pixelated semiconductor detector named Timepix. The Timepix detector consists of electronics and a sensor made from a semiconductor material. The connection of sensor and electronics is done for each pixel individually using bump bonds. Electrons with energies above 3 keV can be detected with the sensor. One electron produces a certain amount of electron-hole pairs according to its energy. The charge then drifts along an electric field to the pixel electronics, where it induces an electric signal. Even without a sensor it is possible to detect an electric signal from approximately 1000 electrons directly in the pixel electronics. Two different detector systems to detect secondary electrons using the Timepix detector were investigated during this thesis. First of all, a hybrid photon detector (HPD) was used to detect single photoelectrons. The HPD consists of a vacuum vessel with an entrance window and a cesium iodine photocathode at the inner surface of the window. Photoelectrons are released from the photocathode by incident light and are accelerated in an electric field towards the Timepix detector, where the point of interaction and the arrival time of the electron is determined. With a proximity focusing setup, a time resolution of 12 ns (with an acceleration voltage of 20 kV between photocathode and Timepix detector) was obtained. The HPD examined in this thesis showed a strong dependence of the dark rate form the acceleration voltage and the pressure in the vacuum vessel. At a pressure of few 10{sup -5} mbar and an acceleration voltage of 20 kV, the dark rate was about 800 Hz per mm{sup 2} area of the read out photocathode. One possibility to reduce the dark rate is to identify ion feedback events. With a slightly modified setup it was possible to reduce the dark rate to 0.5 Hz/mm{sup 2}. To achieve this, a new photocathode was mounted in a shorter distance to the detector. The

  8. Characterisation of two AGATA asymmetric high purity germanium capsules

    International Nuclear Information System (INIS)

    Colosimo, S.J.; Moon, S.; Boston, A.J.; Boston, H.C.; Cresswell, J.R.; Harkness-Brennan, L.; Judson, D.S.; Lazarus, I.H.; Nolan, P.J.; Simpson, J.; Unsworth, C.

    2015-01-01

    The AGATA spectrometer is an array of highly segmented high purity germanium detectors. The spectrometer uses pulse shape analysis in order to track Compton scattered γ-rays to increase the efficiency of nuclear spectroscopy studies. The characterisation of two high purity germanium detector capsules for AGATA of the same A-type has been performed at the University of Liverpool. This work will examine the uniformity of performance of the two capsules, including a comparison of the resolution and efficiency as well as a study of charge collection. The performance of the capsules shows good agreement, which is essential for the efficient operation of the γ-ray tracking array

  9. Characterisation of two AGATA asymmetric high purity germanium capsules

    Energy Technology Data Exchange (ETDEWEB)

    Colosimo, S.J., E-mail: sjc@ns.ph.liv.ac.uk [Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Moon, S.; Boston, A.J.; Boston, H.C.; Cresswell, J.R.; Harkness-Brennan, L.; Judson, D.S. [Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Lazarus, I.H. [STFC Daresbury, Daresbury, Warrington WA4 4AD (United Kingdom); Nolan, P.J. [Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Simpson, J. [STFC Daresbury, Daresbury, Warrington WA4 4AD (United Kingdom); Unsworth, C. [Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom)

    2015-02-11

    The AGATA spectrometer is an array of highly segmented high purity germanium detectors. The spectrometer uses pulse shape analysis in order to track Compton scattered γ-rays to increase the efficiency of nuclear spectroscopy studies. The characterisation of two high purity germanium detector capsules for AGATA of the same A-type has been performed at the University of Liverpool. This work will examine the uniformity of performance of the two capsules, including a comparison of the resolution and efficiency as well as a study of charge collection. The performance of the capsules shows good agreement, which is essential for the efficient operation of the γ-ray tracking array.

  10. Design and Analysis of a Collision Detector for Hybrid Robotic Machine Tools

    Directory of Open Access Journals (Sweden)

    Dan ZHANG

    2015-10-01

    Full Text Available Capacitive sensing depends on the physical parameter changing either the spacing between the two plates or the dielectric constant. Based on this idea, a capacitive based collision detection sensor is proposed and designed in this paper for the purpose of detecting any collision between the end effector and peripheral equipment (e.g., fixture for the three degrees of freedom hybrid robotic machine tools when it is in operation. One side of the finger-like capacitor is attached to the moving platform of the hybrid robotic manipulator and the other side of the finger-like capacitor is attached to the tool. When the tool accidently hits the peripheral equipment, the vibration will make the distance of the capacitor change and therefore trigger the machine to stop. The new design is illustrated and modelled. The capacitance, sensitivity and frequency response of the detector are analyzed in detail, and finally, the fabrication process is presented. The proposed collision detector can also be applied to other machine tools.

  11. Response of a hybrid pixel detector (MEDIPIX3) to different radiation sources for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Chumacero, E. Miguel; De Celis Alonso, B.; Martínez Hernández, M. I.; Vargas, G.; Moreno Barbosa, E., E-mail: emoreno.emb@gmail.com [Facultad de Ciencias Físico Matemáticas, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y Rio Verde, Puebla (Mexico); Moreno Barbosa, F. [Hospital General del Sur Hospital de la Mujer, Puebla (Mexico)

    2014-11-07

    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.

  12. Determination of soil, sand and ore primordial radionuclide concentrations by full-spectrum analyses of high-purity germanium detector spectra

    International Nuclear Information System (INIS)

    Newman, R.T.; Lindsay, R.; Maphoto, K.P.; Mlwilo, N.A.; Mohanty, A.K.; Roux, D.G.; Meijer, R.J. de; Hlatshwayo, I.N.

    2008-01-01

    The full-spectrum analysis (FSA) method was used to determine primordial activity concentrations (ACs) in soil, sand and ore samples, in conjunction with a HPGe detector. FSA involves the least-squares fitting of sample spectra by linear combinations of 238 U, 232 Th and 40 K standard spectra. The differences between the FSA results and those from traditional windows analyses (using regions-of-interest around selected photopeaks) are less than 10% for all samples except zircon ore, where FSA yielded an unphysical 40 K AC

  13. Performance of hybrid photon detector prototypes with 80% active area for the rich counters of LHCB

    International Nuclear Information System (INIS)

    Albrecht, E.; Alemi, M.; Barber, G.; Bibby, J.; Campbell, M.; Duane, A.; Gys, T.; Montenegro, J.; Piedigrossi, D.; Schomaker, R.; Snoeys, W.; Wotton, S.; Wyllie, K.

    2000-01-01

    We report on the ongoing work towards a hybrid photon detector with integrated silicon pixel readout for the ring imaging Cherenkov detectors of the LHCb experiment at the Large Hadron Collider at CERN. The photon detector is based on an electrostatically focussed image intensifier tube geometry where the image is de-magnified by a factor of ∼5. The anode consists of a silicon pixel array, bump-bonded to a binary readout chip with matching pixel electronics. The performance of full-scale prototypes equipped with 61-pixel anodes and external analogue readout is presented. The average signal-to-noise ratio is ∼11 with a peaking time of 1.2 μs. The tube active-to-total surface ratio is 81.7%, which meets the LHCb requirements. The spatial precision is measured to be better than 90 μm. A cluster of three such tubes has been installed in the LHCb RICH 1 prototype where Cherenkov gas rings have been successfully detected. Progress towards the encapsulation of new pixel electronics into a tube is also reported. In particular, the status of the development of a binary readout chip with a peaking time of 25 ns and a low and uniform detection threshold is summarized

  14. Performance of hybrid photon detector prototypes with 80% active area for the rich counters of LHCB

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, E.; Alemi, M.; Barber, G.; Bibby, J.; Campbell, M.; Duane, A.; Gys, T. E-mail: thierry.gys@cern.ch; Montenegro, J.; Piedigrossi, D.; Schomaker, R.; Snoeys, W.; Wotton, S.; Wyllie, K

    2000-03-11

    We report on the ongoing work towards a hybrid photon detector with integrated silicon pixel readout for the ring imaging Cherenkov detectors of the LHCb experiment at the Large Hadron Collider at CERN. The photon detector is based on an electrostatically focussed image intensifier tube geometry where the image is de-magnified by a factor of {approx}5. The anode consists of a silicon pixel array, bump-bonded to a binary readout chip with matching pixel electronics. The performance of full-scale prototypes equipped with 61-pixel anodes and external analogue readout is presented. The average signal-to-noise ratio is {approx}11 with a peaking time of 1.2 {mu}s. The tube active-to-total surface ratio is 81.7%, which meets the LHCb requirements. The spatial precision is measured to be better than 90 {mu}m. A cluster of three such tubes has been installed in the LHCb RICH 1 prototype where Cherenkov gas rings have been successfully detected. Progress towards the encapsulation of new pixel electronics into a tube is also reported. In particular, the status of the development of a binary readout chip with a peaking time of 25 ns and a low and uniform detection threshold is summarized.

  15. A segmented Hybrid Photon Detector with integrated auto-triggering front-end electronics for a PET scanner

    CERN Document Server

    Chesi, Enrico Guido; Joram, C; Mathot, S; Séguinot, Jacques; Weilhammer, P; Ciocia, F; De Leo, R; Nappi, E; Vilardi, I; Argentieri, A; Corsi, F; Dragone, A; Pasqua, D

    2006-01-01

    We describe the design, fabrication and test results of a segmented Hybrid Photon Detector with integrated auto-triggering front-end electronics. Both the photodetector and its VLSI readout electronics are custom designed and have been tailored to the requirements of a recently proposed novel geometrical concept of a Positron Emission Tomograph. Emphasis is put on the PET specific features of the device. The detector has been fabricated in the photocathode facility at CERN.

  16. Recent Results with a segmented Hybrid Photon Detector for a novel parallax-free PET Scanner for Brain Imaging

    CERN Document Server

    Braem, André; Joram, Christian; Mathot, Serge; Séguinot, Jacques; Weilhammer, Peter; Ciocia, F; De Leo, R; Nappi, E; Vilardi, I; Argentieri, A; Corsi, F; Dragone, A; Pasqua, D

    2007-01-01

    We describe the design, fabrication and test results of a segmented Hybrid Photon Detector with integrated auto-triggering front-end electronics. Both the photodetector and its VLSI readout electronics are custom designed and have been tailored to the requirements of a recently proposed novel geometrical concept of a Positron Emission Tomograph. Emphasis is laid on the PET specific features of the device. The detector has been fabricated in the photocathode facility at CERN.

  17. modern utilization of accurate methods for gamma-ray spectral analysis detected by high pure germanium (HPGE) detectors through different applications

    International Nuclear Information System (INIS)

    El-Sayed, M.M.

    2006-01-01

    this thesis presents a novel way for application of wavelet transform theory in gamma-ray spectroscopy . this technique was applied for searching real and weak peaks, solving problem of multiplets, smoothing and de-noising gamma-ray spectra, and using artificial neural network for identifying peaks. a brief description about gamma-ray spectrum analysis is presented. we discussed the necessary formulas and algorithms of wavelet theory to solve these main problems in gamma -ray spectrum analysis. the algorithm of peak search was applied on different types of spectra, IAEA spectra and other sources of gamma spectra. the algorithm of multiplets algorithm was applied successfully on different types of multiplets. the algorithm of de noising was applied successfully on different sources of spectra.finally, a database for neutron activation laboratory is created. this data base consists of five routines, wavelet gamma spectrum analysis, peak identification, elemental concentration , neutron flux determination,and detector efficiency calculation

  18. Germanium and indium

    Science.gov (United States)

    Shanks, W.C. Pat; Kimball, Bryn E.; Tolcin, Amy C.; Guberman, David E.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

    2017-12-19

    Germanium and indium are two important elements used in electronics devices, flat-panel display screens, light-emitting diodes, night vision devices, optical fiber, optical lens systems, and solar power arrays. Germanium and indium are treated together in this chapter because they have similar technological uses and because both are recovered as byproducts, mainly from copper and zinc sulfides.The world’s total production of germanium in 2011 was estimated to be 118 metric tons. This total comprised germanium recovered from zinc concentrates, from fly ash residues from coal burning, and from recycled material. Worldwide, primary germanium was recovered in Canada from zinc concentrates shipped from the United States; in China from zinc residues and coal from multiple sources in China and elsewhere; in Finland from zinc concentrates from the Democratic Republic of the Congo; and in Russia from coal.World production of indium metal was estimated to be about 723 metric tons in 2011; more than one-half of the total was produced in China. Other leading producers included Belgium, Canada, Japan, and the Republic of Korea. These five countries accounted for nearly 95 percent of primary indium production.Deposit types that contain significant amounts of germanium include volcanogenic massive sulfide (VMS) deposits, sedimentary exhalative (SEDEX) deposits, Mississippi Valley-type (MVT) lead-zinc deposits (including Irish-type zinc-lead deposits), Kipushi-type zinc-lead-copper replacement bodies in carbonate rocks, and coal deposits.More than one-half of the byproduct indium in the world is produced in southern China from VMS and SEDEX deposits, and much of the remainder is produced from zinc concentrates from MVT deposits. The Laochang deposit in Yunnan Province, China, and the VMS deposits of the Murchison greenstone belt in Limpopo Province, South Africa, provide excellent examples of indium-enriched deposits. The SEDEX deposits at Bainiuchang, China (located in

  19. Attenuated total internal reflection infrared microspectroscopic imaging using a large-radius germanium internal reflection element and a linear array detector.

    Science.gov (United States)

    Patterson, Brian M; Havrilla, George J

    2006-11-01

    The number of techniques and instruments available for Fourier transform infrared (FT-IR) microspectroscopic imaging has grown significantly over the past few years. Attenuated total internal reflectance (ATR) FT-IR microspectroscopy reduces sample preparation time and has simplified the analysis of many difficult samples. FT-IR imaging has become a powerful analytical tool using either a focal plane array or a linear array detector, especially when coupled with a chemometric analysis package. The field of view of the ATR-IR microspectroscopic imaging area can be greatly increased from 300 x 300 microm to 2500 x 2500 microm using a larger internal reflection element of 12.5 mm radius instead of the typical 1.5 mm radius. This gives an area increase of 70x before aberrant effects become too great. Parameters evaluated include the change in penetration depth as a function of beam displacement, measurements of the active area, magnification factor, and change in spatial resolution over the imaging area. Drawbacks such as large file size will also be discussed. This technique has been successfully applied to the FT-IR imaging of polydimethylsiloxane foam cross-sections, latent human fingerprints, and a model inorganic mixture, which demonstrates the usefulness of the method for pharmaceuticals.

  20. 3D integration technology for hybrid pixel detectors designed for particle physics and imaging experiments

    International Nuclear Information System (INIS)

    Henry, D.; Berthelot, A.; Cuchet, R.; Chantre, C.; Campbell, M.; Tick, T.

    2012-01-01

    Hybrid pixel detectors are now widely used in particle physics experiments and are becoming established at synchrotron light sources. They have also stimulated growing interest in other fields and, in particular, in medical imaging. Through the continuous pursuit of miniaturization in CMOS it has been possible to increase the functionality per pixel while maintaining or even shrinking pixel dimensions. The main constraint on the more extensive use of the technology in all fields is the cost of module building and the difficulty of covering large areas seamlessly. On another hand, in the field of electronic component integration, a new approach has been developed in the last years, called 3D Integration. This concept, based on using the vertical axis for component integration, allows improving the global performance of complex systems. Thanks to this technology, the cost and the form factor of components could be decreased and the performance of the global system could be enhanced. In the field of radiation imaging detectors the advantages of 3D Integration come from reduced inter chip dead area even on large surfaces and from improved detector construction yield resulting from the use of single chip 4-side buttable tiles. For many years, numerous R and centres and companies have put a lot of effort into developing 3D integration technologies and today, some mature technologies are ready for prototyping and production. The core technology of the 3D integration is the TSV (Through Silicon Via) and for many years, LETI has developed those technologies for various types of applications. In this paper we present how one of the TSV approaches developed by LETI, called TSV last, has been applied to a readout wafer containing readout chips intended for a hybrid pixel detector assembly. In the first part of this paper, the 3D design adapted to the read-out chip will be described. Then the complete process flow will be explained and, finally, the test strategy adopted and

  1. Visualisation of Radioactivity in Real-Time on a Tablet Measured by a Hybrid Pixel Detector

    CERN Document Server

    AUTHOR|(SzGeCERN)749233; Bantel, Michael; Grünhaupt, Ulrich

    This work explores a method to visualise and interact with radioactivity over time and space by means of augmented reality on a screen. A prototype, iPadPix, was built to demonstrate use as an intuitive new tool for educative and training purposes. Measured by a hybrid pixel detector, Timepix, traces of radioactive decays are displayed in real- time on a mobile device. Its detection principle and properties are detailed as well as the calibration of the sensor. An embedded board is used to process and forward the sensor data to a tablet over a wireless network connection. Software was developed to processes and overlay signatures of ionising radiation and particles on a live camera feed. It is described here and published as open source.

  2. First images of a digital autoradiography system based on a Medipix2 hybrid silicon pixel detector.

    Science.gov (United States)

    Mettivier, Giovanni; Montesi, Maria Cristina; Russo, Paolo

    2003-06-21

    We present the first images of beta autoradiography obtained with the high-resolution hybrid pixel detector consisting of the Medipix2 single photon counting read-out chip bump-bonded to a 300 microm thick silicon pixel detector. This room temperature system has 256 x 256 square pixels of 55 microm pitch (total sensitive area of 14 x 14 mm2), with a double threshold discriminator and a 13-bit counter in each pixel. It is read out via a dedicated electronic interface and control software, also developed in the framework of the European Medipix2 Collaboration. Digital beta autoradiograms of 14C microscale standard strips (containing separate bands of increasing specific activity in the range 0.0038-32.9 kBq g(-1)) indicate system linearity down to a total background noise of 1.8 x 10(-3) counts mm(-2) s(-1). The minimum detectable activity is estimated to be 0.012 Bq for 36,000 s exposure and 0.023 Bq for 10,800 s exposure. The measured minimum detection threshold is less than 1600 electrons (equivalent to about 6 keV Si). This real-time system for beta autoradiography offers lower pixel pitch and higher sensitive area than the previous Medipix1-based system. It has a 14C sensitivity better than that of micro channel plate based systems, which, however, shows higher spatial resolution and sensitive area.

  3. Development of an ultra-fast X-ray camera using hybrid pixel detectors

    International Nuclear Information System (INIS)

    Dawiec, A.

    2011-05-01

    The aim of the project whose work described in this thesis is part, was to design a high-speed X-ray camera using hybrid pixels applied to biomedical imaging and for material science. As a matter of fact the hybrid pixel technology meets the requirements of these two research fields, particularly by providing energy selection and low dose imaging capabilities. In this thesis, high frame rate X-ray imaging based on the XPAD3-S photons counting chip is presented. Within a collaboration between CPPM, ESRF and SOLEIL, three XPAD3 cameras were built. Two of them are being operated at the beamline of the ESRF and SOLEIL synchrotron facilities and the third one is embedded in the PIXSCAN II irradiation setup of CPPM. The XPAD3 camera is a large surface X-ray detector composed of eight detection modules of seven XPAD3-S chips each with a high-speed data acquisition system. The readout architecture of the camera is based on the PCI Express interface and on programmable FPGA chips. The camera achieves a readout speed of 240 images/s, with maximum number of images limited by the RAM memory of the acquisition PC. The performance of the device was characterized by carrying out several high speed imaging experiments using the PIXSCAN II irradiation setup described in the last chapter of this thesis. (author)

  4. A Hybrid Readout Solution for GaN-Based Detectors Using CMOS Technology

    Directory of Open Access Journals (Sweden)

    Preethi Padmanabhan

    2018-02-01

    Full Text Available Gallium nitride (GaN and its alloys are becoming preferred materials for ultraviolet (UV detectors due to their wide bandgap and tailorable out-of-band cutoff from 3.4 eV to 6.2 eV. GaN based avalanche photodiodes (APDs are particularly suitable for their high photon sensitivity and quantum efficiency in the UV region and for their inherent insensitivity to visible wavelengths. Challenges exist however for practical utilization. With growing interests in such photodetectors, hybrid readout solutions are becoming prevalent with CMOS technology being adopted for its maturity, scalability, and reliability. In this paper, we describe our approach to combine GaN APDs with a CMOS readout circuit, comprising of a linear array of 1 × 8 capacitive transimpedance amplifiers (CTIAs, implemented in a 0.35 µm high voltage CMOS technology. Further, we present a simple, yet sustainable circuit technique to allow operation of APDs under high reverse biases, up to ≈80 V with verified measurement results. The readout offers a conversion gain of 0.43 µV/e−, obtaining avalanche gains up to 103. Several parameters of the CTIA are discussed followed by a perspective on possible hybridization, exploiting the advantages of a 3D-stacked technology.

  5. A Hybrid Readout Solution for GaN-Based Detectors Using CMOS Technology †

    Science.gov (United States)

    Hancock, Bruce; Nikzad, Shouleh; Bell, L. Douglas; Kroep, Kees; Charbon, Edoardo

    2018-01-01

    Gallium nitride (GaN) and its alloys are becoming preferred materials for ultraviolet (UV) detectors due to their wide bandgap and tailorable out-of-band cutoff from 3.4 eV to 6.2 eV. GaN based avalanche photodiodes (APDs) are particularly suitable for their high photon sensitivity and quantum efficiency in the UV region and for their inherent insensitivity to visible wavelengths. Challenges exist however for practical utilization. With growing interests in such photodetectors, hybrid readout solutions are becoming prevalent with CMOS technology being adopted for its maturity, scalability, and reliability. In this paper, we describe our approach to combine GaN APDs with a CMOS readout circuit, comprising of a linear array of 1 × 8 capacitive transimpedance amplifiers (CTIAs), implemented in a 0.35 µm high voltage CMOS technology. Further, we present a simple, yet sustainable circuit technique to allow operation of APDs under high reverse biases, up to ≈80 V with verified measurement results. The readout offers a conversion gain of 0.43 µV/e−, obtaining avalanche gains up to 103. Several parameters of the CTIA are discussed followed by a perspective on possible hybridization, exploiting the advantages of a 3D-stacked technology. PMID:29401655

  6. A Hybrid Readout Solution for GaN-Based Detectors Using CMOS Technology.

    Science.gov (United States)

    Padmanabhan, Preethi; Hancock, Bruce; Nikzad, Shouleh; Bell, L Douglas; Kroep, Kees; Charbon, Edoardo

    2018-02-03

    Gallium nitride (GaN) and its alloys are becoming preferred materials for ultraviolet (UV) detectors due to their wide bandgap and tailorable out-of-band cutoff from 3.4 eV to 6.2 eV. GaN based avalanche photodiodes (APDs) are particularly suitable for their high photon sensitivity and quantum efficiency in the UV region and for their inherent insensitivity to visible wavelengths. Challenges exist however for practical utilization. With growing interests in such photodetectors, hybrid readout solutions are becoming prevalent with CMOS technology being adopted for its maturity, scalability, and reliability. In this paper, we describe our approach to combine GaN APDs with a CMOS readout circuit, comprising of a linear array of 1 × 8 capacitive transimpedance amplifiers (CTIAs), implemented in a 0.35 µm high voltage CMOS technology. Further, we present a simple, yet sustainable circuit technique to allow operation of APDs under high reverse biases, up to ≈80 V with verified measurement results. The readout offers a conversion gain of 0.43 µV/e - , obtaining avalanche gains up to 10³. Several parameters of the CTIA are discussed followed by a perspective on possible hybridization, exploiting the advantages of a 3D-stacked technology.

  7. Behaviour of Belle II ARICH Hybrid Avalanche Photo-Detector in magnetic field

    Science.gov (United States)

    Kindo, H.; Adachi, I.; Dolenec, R.; Hataya, K.; Iori, S.; Iwata, S.; Kakuno, H.; Kataura, R.; Kawai, H.; Kobayashi, T.; Konno, T.; Korpar, S.; Kriz˘an, P.; Kumita, T.; Mrvar, M.; Nishida, S.; Ogawa, K.; Ogawa, S.; Pestotnik, R.; Šantelj, L.; Sumiyoshi, T.; Tabata, M.; Yonenaga, M.; Yusa, Y.

    2017-12-01

    The proximity-focusing Aerogel Ring-Imaging Cherenkov detector (ARICH) has been designed to separate kaons from pions in the forward end-cap of the Belle II spectrometer. The detector will be placed in 1.5 T magnetic field and must have immunity to it. In ARICH R&D, we solve the problem with new equipment called Hybrid Avalanche Photo-Detector (HAPD) which developed by Hamamatsu Photonics. Recently the production of about 500 HAPDs was completed. We test HAPDs in magnetic field in KEK. We found some HAPDs have significant amount of dead time, which reaches up to 30% in the worst case. The dead time is caused by very large (more than 10,000 times larger than a single photon signal) and frequent (∼5 Hz) signals, which make electronics paralysed. The huge signals are observed in about 30% of HAPDs. To identify the origin and understand the mechanism, we perform some extra test of HAPDs. We find a strange dependence of the huge signals to the APD bias voltage. If we reduce the bias voltage applied to one of the 4 APDs by 10 V, the frequency of the huge signals is much reduced. On the other hand, if we reduce the voltage of all the 4 HAPDs, huge signals do not decrease, or even increase in some case. We also find the huge signals seems to be related to the vacuum inside HAPD. We present about the observation of the huge signals of HAPDs in the magnetic field, and our strategy to manage it.

  8. High rate particle tracking and ultra-fast timing with a thin hybrid silicon pixel detector

    Science.gov (United States)

    Fiorini, M.; Aglieri Rinella, G.; Carassiti, V.; Ceccucci, A.; Cortina Gil, E.; Cotta Ramusino, A.; Dellacasa, G.; Garbolino, S.; Jarron, P.; Kaplon, J.; Kluge, A.; Marchetto, F.; Mapelli, A.; Martin, E.; Mazza, G.; Morel, M.; Noy, M.; Nuessle, G.; Perktold, L.; Petagna, P.; Petrucci, F.; Poltorak, K.; Riedler, P.; Rivetti, A.; Statera, M.; Velghe, B.

    2013-08-01

    The Gigatracker (GTK) is a hybrid silicon pixel detector designed for the NA62 experiment at CERN. The beam spectrometer, made of three GTK stations, has to sustain high and non-uniform particle rate (∼ 1 GHz in total) and measure momentum and angles of each beam track with a combined time resolution of 150 ps. In order to reduce multiple scattering and hadronic interactions of beam particles, the material budget of a single GTK station has been fixed to 0.5% X0. The expected fluence for 100 days of running is 2 ×1014 1 MeV neq /cm2, comparable to the one foreseen in the inner trackers of LHC detectors during 10 years of operation. To comply with these requirements, an efficient and very low-mass (< 0.15 %X0) cooling system is being constructed, using a novel microchannel cooling silicon plate. Two complementary read-out architectures have been produced as small-scale prototypes: one is based on a Time-over-Threshold circuit followed by a TDC shared by a group of pixels, while the other makes use of a constant-fraction discriminator followed by an on-pixel TDC. The read-out ASICs are produced in 130 nm IBM CMOS technology and will be thinned down to 100 μm or less. An overview of the Gigatracker detector system will be presented. Experimental results from laboratory and beam tests of prototype bump-bonded assemblies will be described as well. These results show a time resolution of about 170 ps for single hits from minimum ionizing particles, using 200 μm thick silicon sensors.

  9. X-ray Hybrid CMOS Detectors : Recent progress in development and characterization

    Science.gov (United States)

    Chattopadhyay, Tanmoy; Falcone, Abraham; Burrows, David N.

    2017-08-01

    PennState high energy astronomy laboratory has been working on the development and characterization of Hybrid CMOS Detectors (HCDs) for last few years in collaboration with Teledyne Imaging Sensors (TIS). HCDs are preferred over X-ray CCDs due to their higher and flexible read out rate, radiation hardness and low power which make them more suitable for next generation large area X-ray telescopic missions. An H2RG detector with 36 micron pixel pitch and 18 micron ROIC, has been selected for a sounding rocket flight in 2018. The H2RG detector provides ~2.5 % energy resolution at 5.9 keV and ~7 e- read noise when coupled to a cryo-SIDECAR. We could also detect a clear Oxygen line (~0.5 keV) from the detector implying a lower energy threshold of ~0.3 keV. Further improvement in the energy resolution and read noise is currently under progress. We have been working on the characterization of small pixel HCDs (12.5 micron pixel; smallest pixel HCDs developed so far) which is important for the development of next generation high resolution X-ray spectroscopic instrument based on HCDs. Event recognition in HCDs is another exciting prospect which have been successfully shown to work with a 64 X 64 pixel prototype SPEEDSTAR-EXD which use comparators at each pixel to read out only those pixels having detectable signal, thereby providing an order of magnitude improvement in the read out rate. Currently, we are working on the development of a large area SPEEDSTAR-EXD array for the development of a full fledged instrument. HCDs due to their fast read out, can also be explored as a large FOV instrument to study GRB afterglows and variability and spectroscopic study of other astrophysical transients. In this context, we are characterizing a Lobster-HCD system at multiple energies and multiple off-axis angles for future rocket or CubeSate experiments. In this presentation, I will briefly present these new developments and experiments with HCDs and the analysis techniques.

  10. A hybrid, broadband, low noise charge preamplifier for simultaneous high resolution energy and time information with large capacitance semiconductor detector

    International Nuclear Information System (INIS)

    Goyot, M.

    1975-05-01

    A broadband and low noise charge preamplifier was developed in hybrid form, for a recoil spectrometer requiring large capacitance semiconductor detectors. This new hybrid and low cost preamplifier permits good timing information without compromising energy resolution. With a 500 pF external input capacity, it provides two simultaneous outputs: (i) the faster, current sensitive, with a rise time of 9 nsec and 2 mV/MeV on 50 ohms load, (ii) the lower, charge sensitive, with an energy resolution of 14 keV (FWHM Si) using a RC-CR ungated filter of 2 μsec and a FET input protection [fr

  11. Structure of compensating centers in neutron irradiated n-type germanium

    International Nuclear Information System (INIS)

    Erchak, D.P.; Kosobutskij, V.S.; Stel'makh, V.F.

    1989-01-01

    Structural model of one of the main compensating defects of Ge-M1, Ge-M5, Ge-M6 in neutron irradiated (10 18 -10 20 cm -2 ) germanium, strongly alloyed (2x10 18 -3x10 19 cm -3 ) with antimony, phosphorus and arsenic respectively, is suggested. The above mentioned compensating centers are paramagnetic in a positive charge state and represent a vacancy, two nearby germanium atoms of which are replaced with two atoms of corresponding fine donor impurity. It is mainly contributed (63%- for Ge-M5 centers, 56% - for Ge-M6 centers) by orbitals of two germanium atoms neighbouring the vacancy. The angle of the bonds of each of two mentioned germanium atoms with its three neighbours and orientation of maximum electron density of hybride orbital, binding both germanium atoms, is approximately by 5 deg greater the tetrahedral one

  12. High-purity germanium crystal growing

    International Nuclear Information System (INIS)

    Hansen, W.L.; Haller, E.E.

    1982-10-01

    The germanium crystals used for the fabrication of nuclear radiation detectors are required to have a purity and crystalline perfection which is unsurpassed by any other solid material. These crystals should not have a net electrically active impurity concentration greater than 10 10 cm - 3 and be essentially free of charge trapping defects. Such perfect crystals of germanium can be grown only because of the highly favorable chemical and physical properties of this element. However, ten years of laboratory scale and commercial experience has still not made the production of such crystals routine. The origin and control of many impurities and electrically active defect complexes is now fairly well understood but regular production is often interrupted for long periods due to the difficulty of achieving the required high purity or to charge trapping in detectors made from crystals seemingly grown under the required conditions. The compromises involved in the selection of zone refining and crystal grower parts and ambients is discussed and the difficulty in controlling the purity of key elements in the process is emphasized. The consequences of growing in a hydrogen ambient are discussed in detail and it is shown how complexes of neutral defects produce electrically active centers

  13. Semiconductor ionizino. radiation detectors

    International Nuclear Information System (INIS)

    1982-01-01

    Spectrometric semiconductor detectors of ionizing radiation with the electron-hole junction, based on silicon and germanium are presented. The following parameters are given for the individual types of germanium detectors: energy range of detected radiation, energy resolution given as full width at half maximum (FWHM) and full width at one tenth of maximum (FWTM) for 57 Co and 60 Co, detection sensitivity, optimal voltage, and electric capacitance at optimal voltage. For silicon detectors the value of FWHM for 239 Pu is given, the sensitive area and the depth of the sensitive area. (E.S.)

  14. Studies of a hybrid avalanche photo-detector in magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Šantelj, L., E-mail: luka.santelj@kek.jp [High Energy Accelerator Research Organization (KEK) (Japan); Adachi, I. [High Energy Accelerator Research Organization (KEK) (Japan); Sokendai University (Japan); Hataya, K. [Tokyo Metropolitan University (Japan); Iori, S. [Toho University (Japan); Iwata, S.; Kakuno, H. [Tokyo Metropolitan University (Japan); Kataura, R. [Niigata University (Japan); Kawai, H. [Chiba University (Japan); Kindo, H. [Sokendai University (Japan); Korpar, S. [University of Maribor (Slovenia); Jožef Stefan Institute, Ljubljana (Slovenia); Križan, P. [Jožef Stefan Institute, Ljubljana (Slovenia); University of Ljubljana (Slovenia); Mrvar, M. [Jožef Stefan Institute, Ljubljana (Slovenia); Nath, K. [Indian Institute of Technology Guwahati (India); Nishida, S. [High Energy Accelerator Research Organization (KEK) (Japan); Sokendai University (Japan); Ogawa, S. [Niigata University (Japan); Pestotnik, R.; Stanovnik, A.; Seljak, A. [Jožef Stefan Institute, Ljubljana (Slovenia); Sumiyoshi, T. [Tokyo University of Science, Tokyo (Japan); Tabata, M. [Chiba University (Japan); and others

    2017-02-11

    For the Belle II spectrometer a proximity focusing RICH counter with an aerogel radiator (ARICH) will be employed as a PID system in the forward endcap region of the spectrometer. The main challenge was the development of a reliable multichannel sensor for single photons that operates in the high magnetic field of the spectrometer (1.5 T) and withstands the radiation levels expected at the experiment. A 144-channel Hybrid Avalanche Photo-Detector (HAPD) was developed with Hamamatsu Photonics K.K. and the mass production of ∼480 HAPDs was completed recently. While our first tests of HAPD performance in the magnetic field (before mass production) showed no issues, we lately observed a presence of very large signal pulses (∼5000× single photon signal), generated internally within about 20% of HAPDs, while operating in the magnetic field. The rate of these pulses varies from sample to sample. These pulses impact the HAPD performance in two ways: they introduce periods of dead time and, in some cases, damage to the front-end electronics was observed. Here we present conditions under which such large pulses are generated, their properties and impact on HAPD performance, and discuss possible mechanism of their origin.

  15. Design and expected performance of a novel hybrid detector for very-high-energy gamma-ray astrophysics

    Science.gov (United States)

    Assis, P.; Barres de Almeida, U.; Blanco, A.; Conceição, R.; D'Ettorre Piazzoli, B.; De Angelis, A.; Doro, M.; Fonte, P.; Lopes, L.; Matthiae, G.; Pimenta, M.; Shellard, R.; Tomé, B.

    2018-05-01

    Current detectors for Very-High-Energy γ-ray astrophysics are either pointing instruments with a small field of view (Cherenkov telescopes), or large field-of-view instruments with relatively large energy thresholds (extensive air shower detectors). In this article, we propose a new hybrid extensive air shower detector sensitive in an energy region starting from about 100 GeV. The detector combines a small water-Cherenkov detector, able to provide a calorimetric measurement of shower particles at ground, with resistive plate chambers which contribute significantly to the accurate shower geometry reconstruction. A full simulation of this detector concept shows that it is able to reach better sensitivity than any previous gamma-ray wide field-of-view experiment in the sub-TeV energy region. It is expected to detect with a 5σ significance a source fainter than the Crab Nebula in one year at 100 GeV and, above 1 TeV a source as faint as 10% of it. As such, this instrument is suited to detect transient phenomena making it a very powerful tool to trigger observations of variable sources and to detect transients coupled to gravitational waves and gamma-ray bursts.

  16. Use of SRIM and Garfield with Geant4 for the characterization of a hybrid 10B/3He neutron detector

    Science.gov (United States)

    van der Ende, B. M.; Rand, E. T.; Erlandson, A.; Li, L.

    2018-06-01

    This paper describes a method for more complete neutron detector characterization using Geant4's Monte Carlo methods for characterizing overall detector response rate and Garfield interfaced with SRIM for the simulation of the detector's raw pulses, as applied to a hybrid 10B/3He detector. The Geant4 models characterizing the detector's interaction with a 252Cf point source and parallel beams of mono-energetic neutrons (assuming ISO 8529 reference energy values) compare and agree well with calibrated 252Cf measurements to within 6.4%. Validated Geant4 model outputs serve as input to Garfield+SRIM calculations to provide meaningful pulse height spectra. Modifications to Garfield for this work were necessary to account for simultaneous tracking of electrons resulting from proton and triton reaction products from a single 3He neutron capture event, and it was further necessary to interface Garfield with the energy loss, range, and straggling calculations provided by SRIM. Individual raw pulses generated by Garfield+SRIM are also observed to agree well with experimentally measured raw pulses from the detector.

  17. Germanium geochemistry and mineralogy

    Science.gov (United States)

    Bernstein, L.R.

    1985-01-01

    Germanium is enriched in the following geologic environments: 1. (1) iron meteorites and terrestrial iron-nickel; 2. (2) sulfide ore deposits, particularly those hosted by sedimentary rocks; 3. (3) iron oxide deposits; 4. (4) oxidized zones of Ge-bearing sulfide deposits; 5. (5) pegmatites, greisens, and skarns; and 6. (6) coal and lignitized wood. In silicate melts, Ge is highly siderophile in the presence of native iron-nickel; otherwise, it is highly lithophile. Among silicate minerals, Ge is concentrated in those having less polymerized silicate tetrahedra such as olivine and topaz. In deposits formed from hydrothermal solutions, Ge tends to be enriched mostly in either sulfides or in fluorine-bearing phases; it is thus concentrated both in some hydrothermal sulfide deposits and in pegmatites, greisens, and skarns. In sulfide deposits that formed from solutions having low to moderate sulfur activity, Ge is concentrated in sphalerite in amounts up to 3000 ppm. Sulfide deposits that formed from solutions having higher sulfur activity allowed Ge to either form its own sulfides, particularly with Cu, or to substitute for As, Sn, or other metals in sulfosalts. The Ge in hydrothermal fluids probably derives from enrichment during the fractional crystallization of igneous fluids, or is due to the incorporation of Ge from the country rocks, particularly from those containing organic material. Germanium bonds to lignin-derivative organic compounds that are found in peat and lignite, accounting for its common concentration in coals and related organic material. Germanium is precipitated from water together with iron hydroxide, accounting for its concentration in some sedimentary and supergene iron oxide deposits. It also is able to substitute for Fe in magnetite in a variety of geologic environments. In the oxidized zone of Ge-bearing sulfide deposits, Ge is concentrated in oxides, hydroxides, and hydroxy-sulfates, sometimes forming its own minerals. It is particularly

  18. New hydrogen donors in germanium

    International Nuclear Information System (INIS)

    Pokotilo, Yu.M.; Petukh, A.N.; Litvinov, V.V.

    2003-01-01

    The electrophysical properties of the n-type conductivity germanium, irradiated through protons, is studied by the volt-farad method. It is shown that the heat treatment of the implanted germanium at the temperature of 200-300 deg C leads to formation of the fast-diffusing second-rate donors. It is established that the diffusion coefficient of the identified donors coincides with the diffusion coefficient of the atomic hydrogen with an account of the capture on the traps. The conclusion is made, that the atomic hydrogen is the second-rate donor center in germanium [ru

  19. Electrical characteristics of hybrid detector based Gd2O2S:Tb-Selenium for digital radiation imaging

    International Nuclear Information System (INIS)

    Kang, Sang-Sik; Park, Ji-Koon; Choi, Jang-Yong; Cha, Byung-Yul; Cho, Sung-Ho; Nam, Sang-Hee

    2005-01-01

    Fine Gd 2 O 2 S:Tb powders were synthesized by using a solution-combustion method for a high-resolution digital X-ray imaging detector. The PL spectrum showed that the phosphor was fully crystallized and that the Tb 3+ ions substituted well for the Gd 3+ sites. To investigate the X-ray response of the phosphor, a uniform Gd 2 O 2 S:Tb film was grown using a screen-printing method. The X-ray sensitivities of the 100 μm-Gd 2 O 2 S:Tb/30 μm -Se and 200 μm -Se detector were 470 and 420 pC/cm 2 /mR, respectively, at an electric field of 10 V/μm. The results of the study suggest that the hybrid detector has a significant potential in the application of digital radiography and fluoroscopy systems

  20. Investigations of the response of hybrid particle detectors for the Space Environmental Viewing and Analysis Network (SEVAN

    Directory of Open Access Journals (Sweden)

    A. Chilingarian

    2008-02-01

    Full Text Available A network of particle detectors located at middle to low latitudes known as SEVAN (Space Environmental Viewing and Analysis Network is being created in the framework of the International Heliophysical Year (IHY-2007. It aims to improve the fundamental research of the particle acceleration in the vicinity of the Sun and space environment conditions. The new type of particle detectors will simultaneously measure the changing fluxes of most species of secondary cosmic rays, thus turning into a powerful integrated device used for exploration of solar modulation effects. Ground-based detectors measure time series of secondary particles born in cascades originating in the atmosphere by nuclear interactions of protons and nuclei accelerated in the galaxy. During violent solar explosions, sometimes additional secondary particles are added to this "background" flux. The studies of the changing time series of secondary particles shed light on the high-energy particle acceleration mechanisms. The time series of intensities of high energy particles can also provide highly cost-effective information on the key characteristics of interplanetary disturbances. The recent results of the detection of the solar extreme events (2003–2005 by the monitors of the Aragats Space-Environmental Center (ASEC illustrate the wide possibilities provided by new particle detectors measuring neutron, electron and muon fluxes with inherent correlations. We present the results of the simulation studies revealing the characteristics of the SEVAN networks' basic measuring module. We illustrate the possibilities of the hybrid particle detector to measure neutral and charged fluxes of secondary CR, to estimate the efficiency and purity of detection; corresponding median energies of the primary proton flux, the ability to distinguish between neutron and proton initiated GLEs and some other important properties of hybrid particle detectors.

  1. Success and failure of dead-time models as applied to hybrid pixel detectors in high-flux applications

    International Nuclear Information System (INIS)

    Sobott, B. A.; Broennimann, Ch.; Schmitt, B.; Trueb, P.; Schneebeli, M.; Lee, V.; Peake, D. J.; Elbracht-Leong, S.; Schubert, A.; Kirby, N.; Boland, M. J.; Chantler, C. T.; Barnea, Z.; Rassool, R. P.

    2013-01-01

    Detector response functionals are found to have useful but also limited application to synchrotron studies where bunched fills are becoming common. By matching the detector response function to the source temporal structure, substantial improvements in efficiency, count rate and linearity are possible. The performance of a single-photon-counting hybrid pixel detector has been investigated at the Australian Synchrotron. Results are compared with the body of accepted analytical models previously validated with other detectors. Detector functionals are valuable for empirical calibration. It is shown that the matching of the detector dead-time with the temporal synchrotron source structure leads to substantial improvements in count rate and linearity of response. Standard implementations are linear up to ∼0.36 MHz pixel −1 ; the optimized linearity in this configuration has an extended range up to ∼0.71 MHz pixel −1 ; these are further correctable with a transfer function to ∼1.77 MHz pixel −1 . This new approach has wide application both in high-accuracy fundamental experiments and in standard crystallographic X-ray fluorescence and other X-ray measurements. The explicit use of data variance (rather than N 1/2 noise) and direct measures of goodness-of-fit (χ r 2 ) are introduced, raising issues not encountered in previous literature for any detector, and suggesting that these inadequacies of models may apply to most detector types. Specifically, parametrization of models with non-physical values can lead to remarkable agreement for a range of count-rate, pulse-frequency and temporal structure. However, especially when the dead-time is near resonant with the temporal structure, limitations of these classical models become apparent. Further, a lack of agreement at extreme count rates was evident

  2. 18k Channels single photon counting readout circuit for hybrid pixel detector

    International Nuclear Information System (INIS)

    Maj, P.; Grybos, P.; Szczygiel, R.; Zoladz, M.; Sakumura, T.; Tsuji, Y.

    2013-01-01

    We have performed measurements of an integrated circuit named PXD18k designed for hybrid pixel semiconductor detectors used in X-ray imaging applications. The PXD18k integrated circuit, fabricated in CMOS 180 nm technology, has dimensions of 9.64 mm×20 mm and contains approximately 26 million transistors. The core of the IC is a matrix of 96×192 pixels with 100 μm×100 μm pixel size. Each pixel works in a single photon counting mode. A single pixel contains two charge sensitive amplifiers with Krummenacher feedback scheme, two shapers, two discriminators (with independent thresholds A and B) and two 16-bit ripple counters. The data are read out via eight low voltage differential signaling (LVDS) outputs with 100 Mbps rate. The power consumption is dominated by analog blocks and it is about 23 μW/pixel. The effective peaking time at the discriminator input is 30 ns and is mainly determined by the time constants of the charge sensitive amplifier (CSA). The gain is equal to 42.5 μV/e − and the equivalent noise charge is 168 e − rms (with bump-bonded silicon pixel detector). Thanks to the use of trim DACs in each pixel, the effective threshold spread at the discriminator input is only 1.79 mV. The dead time of the front end electronics for a standard setting is 172 ns (paralyzable model). In the standard readout mode (when the data collection time is separated from the time necessary to readout data from the chip) the PXD18k IC works with two energy thresholds per pixel. The PXD18k can also be operated in the continuous readout mode (with a zero dead time) where one can select the number of bits readout from each pixel to optimize the PXD18k frame rate. For example, for reading out 16 bits/pixel the frame rate is 2.7 kHz and for 4 bits/pixel it rises to 7.1 kHz.

  3. 18k Channels single photon counting readout circuit for hybrid pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    Maj, P., E-mail: piotr.maj@agh.edu.pl [AGH University of Science and Technology, Department of Measurements and Electronics, Al. Mickiewicza 30, 30-059 Krakow (Poland); Grybos, P.; Szczygiel, R.; Zoladz, M. [AGH University of Science and Technology, Department of Measurements and Electronics, Al. Mickiewicza 30, 30-059 Krakow (Poland); Sakumura, T.; Tsuji, Y. [X-ray Analysis Division, Rigaku Corporation, Matsubara, Akishima, Tokyo 196-8666 (Japan)

    2013-01-01

    We have performed measurements of an integrated circuit named PXD18k designed for hybrid pixel semiconductor detectors used in X-ray imaging applications. The PXD18k integrated circuit, fabricated in CMOS 180 nm technology, has dimensions of 9.64 mm Multiplication-Sign 20 mm and contains approximately 26 million transistors. The core of the IC is a matrix of 96 Multiplication-Sign 192 pixels with 100 {mu}m Multiplication-Sign 100 {mu}m pixel size. Each pixel works in a single photon counting mode. A single pixel contains two charge sensitive amplifiers with Krummenacher feedback scheme, two shapers, two discriminators (with independent thresholds A and B) and two 16-bit ripple counters. The data are read out via eight low voltage differential signaling (LVDS) outputs with 100 Mbps rate. The power consumption is dominated by analog blocks and it is about 23 {mu}W/pixel. The effective peaking time at the discriminator input is 30 ns and is mainly determined by the time constants of the charge sensitive amplifier (CSA). The gain is equal to 42.5 {mu}V/e{sup -} and the equivalent noise charge is 168 e{sup -} rms (with bump-bonded silicon pixel detector). Thanks to the use of trim DACs in each pixel, the effective threshold spread at the discriminator input is only 1.79 mV. The dead time of the front end electronics for a standard setting is 172 ns (paralyzable model). In the standard readout mode (when the data collection time is separated from the time necessary to readout data from the chip) the PXD18k IC works with two energy thresholds per pixel. The PXD18k can also be operated in the continuous readout mode (with a zero dead time) where one can select the number of bits readout from each pixel to optimize the PXD18k frame rate. For example, for reading out 16 bits/pixel the frame rate is 2.7 kHz and for 4 bits/pixel it rises to 7.1 kHz.

  4. Flip chip assembly of thinned chips for hybrid pixel detector applications

    International Nuclear Information System (INIS)

    Fritzsch, T; Zoschke, K; Rothermund, M; Oppermann, H; Woehrmann, M; Ehrmann, O; Lang, K D; Huegging, F

    2014-01-01

    There is a steady trend to ultra-thin microelectronic devices. Especially for future particle detector systems a reduced readout chip thickness is required to limit the loss of tracking precision due to scattering. The reduction of silicon thickness is performed at wafer level in a two-step thinning process. To minimize the risk of wafer breakage the thinned wafer needs to be handled by a carrier during the whole process chain of wafer bumping. Another key process is the flip chip assembly of thinned readout chips onto thin sensor tiles. Besides the prevention of silicon breakage the minimization of chip warpage is one additional task for a high yield and reliable flip chip process. A new technology using glass carrier wafer will be described in detail. The main advantage of this technology is the combination of a carrier support during wafer processing and the chip support during flip chip assembly. For that a glass wafer is glue-bonded onto the backside of the thinned readout chip wafer. After the bump deposition process the glass-readout chip stack is diced in one step. Finally the glass carrier chip is released by laser illumination after flip chip assembly of the readout chip onto sensor tile. The results of the flip chip assembly process development for the ATLAS IBL upgrade are described more in detail. The new ATLAS FEI4B chip with a size of 20 × 19 mm 2 is flip chip bonded with a thickness of only 150 μm, but the capability of this technology has been demonstrated on hybrid modules with a reduced readout chip thickness of down to 50 μm which is a major step for ultra-thin electronic systems

  5. Circular-detector array hybrid emission computed tomograph, HEADTOME-II

    Energy Technology Data Exchange (ETDEWEB)

    Uemura, Kazuo; Kanno, Iwao; Miura, Yuko; Miura, Syuichi [Research Inst. of Brain and Blood Vessels, Akita (Japan); Hattori, Hiroyuki; Hirose, Yoshiharu; Nagata, Takashi; Higashi, Yoshihumi

    1982-08-01

    The HEADTOME-II is a successor of the original hybrid ECT, the HEADTOME-I, which was built and used in Research Institute of Brain and Blood Vessels, Akita. The new machine has three detector rings comprising 64 Nal crystals each, the axial length of which is 30 mm, 100 mm in total for three rings including 5 mm lead shield between the rings, and is long enough to examine most of the brain at a given time. The system sensitivity for positrons is 27.5 kcps/..mu..Ci/ml for intra-ring coincidence and 36.5 kcps for inter-ring coincidence. Spatial resolution is 10 mm FWHM at the center of the field of view. For single photon ECT study, new ''Turbofan'' rotating collimators, high sensitivity H.S. and high resolution H.R., are adopted. The collimators for single photons and positrons can be selected by manual operation. The system sensitivity for sup(99m)Tc is, 52.5 kcps/..mu..Ci/ml by H.S. and 13.8 kcps by H.R. collimator. Spatial resolution at the center of the field of view is 20 mm for H.S. and 11 mm for H.R. respectively. High quality images have been obtained by sup(99m)Tc, /sup 81/mKr, /sup 111/In and /sup 11/C. The regional cerebral blood flow study by /sup 133/Xe inhalation or intra-venous injection has been tried and good results are obtained.

  6. A circular-detector array hybrid emission computed tomograph, HEADTOME-II

    International Nuclear Information System (INIS)

    Uemura, Kazuo; Kanno, Iwao; Miura, Yuko; Miura, Syuichi; Hattori, Hiroyuki; Hirose, Yoshiharu; Nagata, Takashi; Higashi, Yoshihumi.

    1982-01-01

    The HEADTOME-II is a successor of the original hybrid ECT, the HEADTOME-I, which was built and used in Research Institute of Brain and Blood Vessels, Akita. The new machine has three detector rings comprising 64 Nal crystals each, the axial length of which is 30 mm, 100 mm in total for three rings including 5 mm lead shield between the rings, and is long enought to examine the most part of the brain at a time. The system sensitivity for positrons is 27.5 kcps/μCi/ml for intra-ring coincidence and 36.5 kcps for inter-ring coincidence. Spatial resolution is 10 mm FWHM at the center of the field of view. For single photon ECT study, new ''Turbofan'' rotaing collimators, high sensitivity H.S. and high resolution H.R., are adopted. The collimators for single photons and positrons can be selected by manual operation. The system sensitivity for sup(99m)Tc is, 52.5 kcps/μCi/ml by H.S. and 13.8 kcps by H.R. collimator. Spatial resolution at the center of the field of view is 20 mm for H.S. and 11 mm for H.R. respectively. High quality images have been obtained by sup(99m)Tc, 81 mKr, 111 In and 11 C. The regional cerebral blood flow study by 133 Xe inhalation or intra-venous injection has been tried and good results are obtained. (author)

  7. Shimming with permanent magnets for the x-ray detector in a hybrid x-ray∕MR system

    Science.gov (United States)

    Wen, Zhifei; Fahrig, Rebecca; Williams, Scott T.; Pelc, Norbert J.

    2008-01-01

    In this x-ray∕MR hybrid system an x-ray flat panel detector is placed under the patient cradle, close to the MR volume of interest (VOI), where the magnetic field strength is ∼0.5 T. Immersed in this strong field, several electronic components inside the detector become magnetized and create an additional magnetic field that is superimposed on the original field of the MR scanner. Even after linear shimming, the field homogeneity of the MR scanner remains disrupted by the detector. The authors characterize the field due to the detector with the field of two magnetic dipoles and further show that two sets of permanent magnets (NdFeB) can withstand the main magnetic field and compensate for the nonlinear components of the additional field. The ideal number of magnets and their locations are calculated based on a field map measured with the detector in place. Experimental results demonstrate great promise for this technique, which may be useful in many settings where devices with magnetic components need to be placed inside or close to an MR scanner. PMID:18841840

  8. First operation of a hybrid photon detector prototype with electrostatic cross-focussing and integrated silicon pixel readout

    International Nuclear Information System (INIS)

    Alemi, M.; Campbell, M.; Gys, T.; Mikulec, B.; Piedigrossi, D.; Puertolas, D.; Rosso, E.; Schomaker, R.; Snoeys, W.; Wyllie, K.

    2000-01-01

    We report on the first operation of a hybrid photon detector prototype with integrated silicon pixel readout for the ring imaging Cherenkov detectors of the LHCb experiment. The photon detector is based on a cross-focussed image intensifier tube geometry where the image is de-magnified by a factor of 4. The anode consists of a silicon pixel array, bump-bonded to a binary readout chip with matching pixel electronics. The prototype has been characterized using a low-intensity light-emitting diode operated in pulsed mode. Its performance in terms of single-photoelectron detection efficiency and imaging properties is presented. A model of photoelectron detection is proposed, and is shown to be in good agreement with the experimental data. It includes an estimate of the charge signal generated in the silicon detector, and the combined effects of the comparator threshold spread of the pixel readout chip, charge sharing at the pixel boundaries and back-scattering of the photoelectrons at the silicon detector surface

  9. First operation of a hybrid photon detector prototype with electrostatic cross-focussing and integrated silicon pixel readout

    Energy Technology Data Exchange (ETDEWEB)

    Alemi, M.; Campbell, M.; Gys, T. E-mail: thierry.gys@cern.ch; Mikulec, B.; Piedigrossi, D.; Puertolas, D.; Rosso, E.; Schomaker, R.; Snoeys, W.; Wyllie, K

    2000-07-11

    We report on the first operation of a hybrid photon detector prototype with integrated silicon pixel readout for the ring imaging Cherenkov detectors of the LHCb experiment. The photon detector is based on a cross-focussed image intensifier tube geometry where the image is de-magnified by a factor of 4. The anode consists of a silicon pixel array, bump-bonded to a binary readout chip with matching pixel electronics. The prototype has been characterized using a low-intensity light-emitting diode operated in pulsed mode. Its performance in terms of single-photoelectron detection efficiency and imaging properties is presented. A model of photoelectron detection is proposed, and is shown to be in good agreement with the experimental data. It includes an estimate of the charge signal generated in the silicon detector, and the combined effects of the comparator threshold spread of the pixel readout chip, charge sharing at the pixel boundaries and back-scattering of the photoelectrons at the silicon detector surface.

  10. Long-term radiation damage to a spaceborne germanium spectrometer

    CERN Document Server

    Kurczynski, P; Hull, E L; Palmer, D; Harris, M J; Seifert, H; Teegarden, B J; Gehrels, N; Cline, T L; Ramaty, R; Sheppard, D; Madden, N W; Luke, P N; Cork, C P; Landis, D A; Malone, D F; Hurley, K

    1999-01-01

    The Transient Gamma-Ray Spectrometer aboard the Wind spacecraft in deep space has observed gamma-ray bursts and solar events for four years. The germanium detector in the instrument has gradually deteriorated from exposure to the approx 10 sup 8 p/cm sup 2 /yr(>100 MeV) cosmic-ray flux. Low-energy tailing and loss of efficiency, attributed to hole trapping and conversion of the germanium from n- to p-type as a result of crystal damage, were observed. Raising the detector bias voltage ameliorated both difficulties and restored the spectrometer to working operation. Together, these observations extend our understanding of the effects of radiation damage to include the previously unsuccessfully studied regime of long-term operation in space. (author)

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

    International Nuclear Information System (INIS)

    Hall, R.N.

    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 0 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 and subsequently diffusing some of the lithium back out through the surface to create a deep p-n junction. Production of coaxial germanium detectors comprising deep p-n junctions by the lithium diffusion process is described

  12. Development of a 144-channel Hybrid Avalanche Photo-Detector for Belle II ring-imaging Cherenkov counter with an aerogel radiator

    Energy Technology Data Exchange (ETDEWEB)

    Nishida, S., E-mail: shohei.nishida@kek.jp [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan); Adachi, I. [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan); Hamada, N. [Toho University, Funabashi (Japan); Hara, K. [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan); Iijima, T. [Nagoya University, Nagoya (Japan); Iwata, S.; Kakuno, H. [Tokyo Metropolitan University, Hachioji (Japan); Kawai, H. [Chiba University, Chiba (Japan); Korpar, S.; Krizan, P. [Jozef Stefan Institute, Ljubljana (Slovenia); Ogawa, S. [Toho University, Funabashi (Japan); Pestotnik, R.; Ŝantelj, L.; Seljak, A. [Jozef Stefan Institute, Ljubljana (Slovenia); Sumiyoshi, T. [Tokyo Metropolitan University, Hachioji (Japan); Tabata, M. [Chiba University, Chiba (Japan); Tahirovic, E. [Jozef Stefan Institute, Ljubljana (Slovenia); Yoshida, K. [Tokyo Metropolitan University, Hachioji (Japan); Yusa, Y. [Niigata University, Niigata (Japan)

    2015-07-01

    The Belle II detector, a follow up of the very successful Belle experiment, is under construction at the SuperKEKB electron–positron collider at KEK in Japan. For the PID system in the forward region of the spectrometer, a proximity-focusing ring-imaging Cherenkov counter with an aerogel radiator is being developed. For the position sensitive photon sensor, a 144-channel Hybrid Avalanche Photo-Detector has been developed with Hamamatsu Photonics K.K. In this report, we describe the specification of the Hybrid Avalanche Photo-Detector and the status of the mass production.

  13. Design and realization of a fast low noise electronics for a hybrid pixel X-ray detector dedicated to small animal imaging

    International Nuclear Information System (INIS)

    Chantepie, Benoit

    2008-01-01

    Since the invention of computerized tomography (CT), charge integration detector were widely employed for X-ray biomedical imaging applications. Nevertheless, other options exist. A new technology of direct detection using semiconductors has been developed for high energy physics instrumentation. This new technology, called hybrid pixel detector, works in photon counting mode and allows for selecting the minimum energy of the counted photons. The imXgam research team at CPPM develops the PIXSCAN demonstrator, a CT-scanner using the hybrid pixel detector XPAD. The aim of this project is to evaluate the improvement on image quality and on dose delivered during X-ray examinations of a small animal. After a first prototype of hybrid pixel detector XPAD1 proving the feasibility of the project, a complete imager XPAD2 was designed and integrated in the PIXSCAN demonstrator. Since then, with the evolution of microelectronic industry, important improvements are conceivable. To reducing the size of pixels and to improving the energy resolution of detectors, a third design XPAD3 was conceived and will be soon integrated in a second generation of PIXSCAN demonstrator. In this project, my thesis's work consisted in taking part to the design of the detector readout electronics, to the characterization of the chips and of the hybrid pixel detectors, and also to the definition of an auto-zeroing architecture for pixels. (author) [fr

  14. Porous germanium multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Garralaga Rojas, Enrique; Hensen, Jan; Brendel, Rolf [Institut fuer Solarenergieforschung Hameln (ISFH), Emmerthal (Germany); Carstensen, Juergen; Foell, Helmut [Chair for General Materials Science, Faculty of Engineering, Christian-Albrechts-University of Kiel (Germany)

    2011-06-15

    We present the reproducible fabrication of porous germanium (PGe) single- and multilayers. Mesoporous layers form on heavily doped 4'' p-type Ge wafers by electrochemical etching in highly concentrated HF-based electrolytes with concentrations in a range of 30-50 wt.%. Direct PGe formation is accompanied by a constant dissolution of the already-formed porous layer at the electrolyte/PGe interface, hence yielding a thinner substrate after etching. This effect inhibits multilayer formation as the starting layer is etched while forming the second layer. We avoid dissolution of the porous layer by alternating the etching bias from anodic to cathodic. PGe formation occurs during anodic etching whereas the cathodic step passivates pore walls with H-atoms and avoids electropolishing. The passivation lasts a limited time depending on the etching current density and electrolyte concentration, necessitating a repetition of the cathodic step at suitable intervals. With optimized alternating bias mesoporous multilayer production is possible. We control the porosity of each single layer by varying the etching current density and the electrolyte (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Calculation of total counting efficiency of a NaI(Tl) detector by hybrid Monte-Carlo method for point and disk sources

    Energy Technology Data Exchange (ETDEWEB)

    Yalcin, S. [Education Faculty, Kastamonu University, 37200 Kastamonu (Turkey)], E-mail: yalcin@gazi.edu.tr; Gurler, O.; Kaynak, G. [Department of Physics, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey); Gundogdu, O. [Department of Physics, School of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2007-10-15

    This paper presents results on the total gamma counting efficiency of a NaI(Tl) detector from point and disk sources. The directions of photons emitted from the source were determined by Monte-Carlo techniques and the photon path lengths in the detector were determined by analytic equations depending on photon directions. This is called the hybrid Monte-Carlo method where analytical expressions are incorporated into the Monte-Carlo simulations. A major advantage of this technique is the short computation time compared to other techniques on similar computational platforms. Another advantage is the flexibility for inputting detector-related parameters (such as source-detector distance, detector radius, source radius, detector linear attenuation coefficient) into the algorithm developed, thus making it an easy and flexible method to apply to other detector systems and configurations. The results of the total counting efficiency model put forward for point and disc sources were compared with the previous work reported in the literature.

  16. Calculation of total counting efficiency of a NaI(Tl) detector by hybrid Monte-Carlo method for point and disk sources

    International Nuclear Information System (INIS)

    Yalcin, S.; Gurler, O.; Kaynak, G.; Gundogdu, O.

    2007-01-01

    This paper presents results on the total gamma counting efficiency of a NaI(Tl) detector from point and disk sources. The directions of photons emitted from the source were determined by Monte-Carlo techniques and the photon path lengths in the detector were determined by analytic equations depending on photon directions. This is called the hybrid Monte-Carlo method where analytical expressions are incorporated into the Monte-Carlo simulations. A major advantage of this technique is the short computation time compared to other techniques on similar computational platforms. Another advantage is the flexibility for inputting detector-related parameters (such as source-detector distance, detector radius, source radius, detector linear attenuation coefficient) into the algorithm developed, thus making it an easy and flexible method to apply to other detector systems and configurations. The results of the total counting efficiency model put forward for point and disc sources were compared with the previous work reported in the literature

  17. Analysis of test-beam data with hybrid pixel detector prototypes for the Compact LInear Collider (CLIC) vertex detectors

    CERN Document Server

    Pequegnot, Anne-Laure

    2013-01-01

    The LHC is currently the most powerful accelerator in the world. This proton-proton collider is now stoppped to increase significantly its luminosity and energy, which would provide a larger discovery potential in 2014 and beyond. A high-energy $e^{+}e^{-}$ collider, such as CLIC, is an option to complement and to extend the LHC physics programme. Indeed, a lepton collider gives access to additional physics processes, beyond those observable at the LHC, and therefore provides new discovery potential. It can also provide complementary and/or more precise information about new physics uncovered at the LHC. Many essential features of a detector are required to deliver the full physics potential of this CLIC machine. In this present report, I present my work on the vertex detector R\\&D for this future linear collider, which aims at developping highly granular and ultra-thin position sensitive detection devices with very low power consumption and fast time-stamping capability. We tested here thin silicon pixel...

  18. Carbon in high-purity germanium

    International Nuclear Information System (INIS)

    Haller, E.E.; Hansen, W.L.; Luke, P.; McMurray, R.; Jarrett, B.

    1981-10-01

    Using 14 C-spiked pyrolytic graphite-coated quartz crucibles for the growth of nine ultra-pure germanium single crystals, we have determined the carbon content and distribution in these crystals. Using autoradiography, we observe a rapidly decreasing carbon cluster concentration in successively grown crystals. Nuclear radiation detectors made from the crystals measure the betas from the internally decaying 14 C nuclei with close to 100% efficiency. An average value for the total carbon concentration [ 14 C + 12 C] is approx. 2 x 10 14 cm -3 , a value substantially larger than expected from earlier metallurgical studies. Contrary to the most recent measurement, we find the shape of the beta spectrum to agree very well with the statistical shape predicted for allowed transitions

  19. Design and construction of a small animal PET/CT scanner combining scintillation Phoswich modules and hybrid pixels detectors

    International Nuclear Information System (INIS)

    Nicol, St.

    2010-07-01

    The pathway that has been followed by the imXgam team at CPPM was to combine on a single rotating device the detector modules of the small animal PET scanner ClearPET with a photon counting X-ray detector in order to perform simultaneous acquisition of images from the anatomy (X-ray CT) and from the metabolic function (PET) of the common field-of-view. A preliminary study of the hybrid imaging system ClearPET/XPAD3 carried out using Gate led us to form a new PET detection assembly based on 21 Phoswich modules, to fix the design of the PET/CT device, as well as to study and solve the difficulties arising from simultaneous hybrid imaging. Last but not least, the simulation tool also allowed us for thinking how well such a system could judiciously use the spatial and temporal correlations between anatomic and functional information. From an instrumentation point of view, we succeeded to set up the ClearPET/XPAD3 prototype. Once both imaging systems were operational individually, we demonstrated on one side that the ClearPET prototype was perfectly capable of performing correctly in simultaneous acquisition conditions, providing that the detector modules were appropriately shielded. On the other side, the new generation of the hybrid pixel camera using the XPAD3-S chip proved to be quite promising given the good quality of the first reconstructed images. Finally, the proof of concept of simultaneous PET/CT data acquisition was made using a sealed positron source and an X-ray tube. (author)

  20. Silicon PIN diode hybrid arrays for charged particle detection: Building blocks for vertex detectors at the SSC

    International Nuclear Information System (INIS)

    Kramer, G.; Gaalema, S.; Shapiro, S.L.; Dunwoodie, W.M.; Arens, J.F.; Jernigan, J.G.

    1989-05-01

    Two-dimensional arrays of solid state detectors have long been used in visible and infrared systems. Hybrid arrays with separately optimized detector and readout substrates have been extensively developed for infrared sensors. The characteristics and use of these infrared readout chips with silicon PIN diode arrays produced by MICRON SEMICONDUCTOR for detecting high-energy particles are reported. Some of these arrays have been produced in formats as large as 512 /times/ 512 pixels; others have been radiation hardened to total dose levels beyond 1 Mrad. Data generation rates of 380 megasamples/second have been achieved. Analog and digital signal transmission and processing techniques have also been developed to accept and reduce these high data rates. 9 refs., 15 figs., 2 tabs

  1. CdTe hybrid pixel detector for imaging with thermal neutrons

    Czech Academy of Sciences Publication Activity Database

    Jakůbek, J.; Mettivier, G.; Montesi, M.C.; Pospíšil, S.; Russo, P.; Vacík, Jiří

    2006-01-01

    Roč. 563, č. 1 (2006), s. 238-241 ISSN 0168-9002 R&D Pro jects: GA MŠk 1P04LA211 Institutional research plan: CEZ:AV0Z10480505 Keywords : neutronography * pixel detector * semiconductor detector Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.185, year: 2006

  2. Physics studies with ICARUS and a hybrid ionization and scintillation fiber detector

    International Nuclear Information System (INIS)

    Cline, D.B.

    1992-01-01

    We discuss the physics possibilities for the ICARUS detector currently being tested at CERN. The physics potential goes from a massive proton decay detector to the study of solar neutrinos. In addition, the detection of ν μ → ν τ and ν e → ν τ will be possible with such a detector. One major topic involves the possibility of a complete determination of the MSW solar neutrino parameters with the ICARUS. The possibility of detecting WIMPS with a scintillating fiber liquid Argon (Ar) detector or fiber Xenon (Xe) detector doped with Ar is also described. Some comments on the measurement of the 42 Ar level from an experiment at the Gran Sasso will be made

  3. γ-ray tracking in germanium: the backtracking method

    International Nuclear Information System (INIS)

    Marel, J. van der; Cederwall, B.

    2002-01-01

    In the framework of a European TMR network project the concept for a γ-ray tracking array is being developed for nuclear physics spectroscopy in the energy range of ∼10 keV up to several MeV. The tracking array will consist of a large number of position-sensitive germanium detectors in a spherical geometry around a target. Due to the high segmentation, a Compton scattered γ-ray will deposit energy in several different segments. A method has been developed to reconstruct the tracks of multiple coincident γ-rays and to find their initial energies. By starting from the final point the track can be reconstructed backwards to the origin with the help of the photoelectric and Compton cross-sections and the Compton scatter formula. Every reconstructed track is given a figure of merit, thus allowing suppression of wrongly reconstructed tracks and γ-rays that have scattered out of the detector system. This so-called backtracking method has been tested on simulated events in a shell-like geometry for germanium and in planar geometries for silicon, germanium and CdTe

  4. A review of the developments of radioxenon detectors for nuclear explosion monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Sivels, Ciara B.; McIntyre, Justin I.; Bowyer, Theodore W.; Kalinowski, Martin B.; Pozzi, Sara A.

    2017-09-27

    Developments in radioxenon monitoring since the implementation of the International Monitoring System are reviewed with emphasis on the most current technologies to improve detector sensitivity and resolution. The nuclear detectors reviewed include combinations of plastic and NaI(Tl) detectors, high purity germanium detectors, silicon detectors, and phoswich detectors. The minimum detectable activity and calibration methods for the various detectors are also discussed.

  5. A detector insert based on continuous scintillators for hybrid MR–PET imaging of the human brain

    Energy Technology Data Exchange (ETDEWEB)

    Rato Mendes, P., E-mail: pedro.rato@ciemat.es [CIEMAT, Avenida Complutense 40, 28040 Madrid (Spain); Cuerdo, R.; Sarasola, I.; García de Acilu, P.; Navarrete, J.; Vela, O.; Oller, J.C.; Cela, J.M. [CIEMAT, Avenida Complutense 40, 28040 Madrid (Spain); Núñez, L.; Pastrana, M. [Hospital Universitario Puerta de Hierro Majadahonda, Manuel de Falla 1, 28222 Majadahonda (Spain); Romero, L.; Willmott, C. [CIEMAT, Avenida Complutense 40, 28040 Madrid (Spain)

    2013-02-21

    We are developing a positron emission tomography (PET) insert for existing magnetic resonance (MR) equipment, aiming at hybrid MR–PET imaging. Our detector block design is based on trapezoid-shaped LYSO:Ce monolithic scintillators coupled to magnetically compatible Hamamatsu S8550-02 silicon avalanche photodiode (APD) matrices with a dedicated ASIC front-end readout from GammaMedica-Ideas (Fornebu, Norway). The detectors are position sensitive, capable of determining the incidence point of 511 keV gammas with an intrinsic spatial resolution on the order of 2 mm by means of supervised learning neural-network (NN) algorithms. These algorithms, apart from providing continuous coordinates, are also intrinsically corrected for depth of interaction effects and thus parallax-free. Recently we have implemented an advanced prototype featuring two heads with four detector blocks each and final front-end and readout electronics, improving the spatial resolution of reconstructed point source images down to 1.7 mm full width at half maximum (FWHM). Presently we are carrying out operational tests of components and systems under magnetic fields using a 3 T MR scanner. In this paper we present a description of our project, a summary of the results obtained with laboratory prototypes, and the strategy to build and install the complete system at the nuclear medicine department of a collaborating hospital.

  6. A detector insert based on continuous scintillators for hybrid MR–PET imaging of the human brain

    International Nuclear Information System (INIS)

    Rato Mendes, P.; Cuerdo, R.; Sarasola, I.; García de Acilu, P.; Navarrete, J.; Vela, O.; Oller, J.C.; Cela, J.M.; Núñez, L.; Pastrana, M.; Romero, L.; Willmott, C.

    2013-01-01

    We are developing a positron emission tomography (PET) insert for existing magnetic resonance (MR) equipment, aiming at hybrid MR–PET imaging. Our detector block design is based on trapezoid-shaped LYSO:Ce monolithic scintillators coupled to magnetically compatible Hamamatsu S8550-02 silicon avalanche photodiode (APD) matrices with a dedicated ASIC front-end readout from GammaMedica-Ideas (Fornebu, Norway). The detectors are position sensitive, capable of determining the incidence point of 511 keV gammas with an intrinsic spatial resolution on the order of 2 mm by means of supervised learning neural-network (NN) algorithms. These algorithms, apart from providing continuous coordinates, are also intrinsically corrected for depth of interaction effects and thus parallax-free. Recently we have implemented an advanced prototype featuring two heads with four detector blocks each and final front-end and readout electronics, improving the spatial resolution of reconstructed point source images down to 1.7 mm full width at half maximum (FWHM). Presently we are carrying out operational tests of components and systems under magnetic fields using a 3 T MR scanner. In this paper we present a description of our project, a summary of the results obtained with laboratory prototypes, and the strategy to build and install the complete system at the nuclear medicine department of a collaborating hospital

  7. The TDCpix readout ASIC: A 75ps resolution timing front-end for the NA62 Gigatracker hybrid pixel detector

    CERN Document Server

    Kluge, A; Bonacini, S; Jarron, P; Kaplon, J; Morel, M; Noy, M; Perktold, L; Poltorak, K

    2013-01-01

    The TDCpix is a novel pixel readout ASIC for the NA62 Gigatracker detector. NA62 is a new experiment being installed at the CERN Super Proton Synchrotron. Its Gigatracker detector shall provide on-beam tracking and time stamping of individual particles with a time resolution of 150 ps rms. It will consist of three tracking stations, each with one hybrid pixel sensor. The peak fl ow of particles crossing the detector modules reaches 1.27 MHz/mm 2 for a total rate of about 0.75 GHz. Ten TDCpix chips will be bump-bonded to every silicon pixel sensor. Each chip shall perform time stamping of 100 M particle hits per second with a detection ef fi ciency above 99% and a timing accuracy better than 200 ps rms for an overall three-station-setup time resolution of better than 150 ps. The TDCpix chip has been designed in a 130 nm CMOS technology. It will feature 45 40 square pixels of 300 300 μ m 2 and a complex End of Column peripheral region including an array of TDCs based on DLLs, four high speed serializers, a low...

  8. Pixel readout ASIC for an APD based 2D X-ray hybrid pixel detector with sub-nanosecond resolution

    Energy Technology Data Exchange (ETDEWEB)

    Thil, Ch., E-mail: christophe.thil@ziti.uni-heidelberg.d [Heidelberg University, Institute of Computer Engineering, B6, 26, 68161 Mannheim (Germany); Baron, A.Q.R. [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Fajardo, P. [ESRF, Polygone Scientifique Louis Neel, 6, rue Jules Horowitz, 38000 Grenoble (France); Fischer, P. [Heidelberg University, Institute of Computer Engineering, B6, 26, 68161 Mannheim (Germany); Graafsma, H. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Rueffer, R. [ESRF, Polygone Scientifique Louis Neel, 6, rue Jules Horowitz, 38000 Grenoble (France)

    2011-02-01

    The fast response and the short recovery time of avalanche photodiodes (APDs) in linear mode make those devices ideal for direct X-ray detection in applications requiring high time resolution or counting rate. In order to provide position sensitivity, the XNAP project aims at creating a hybrid pixel detector with nanosecond time resolution based on a monolithic APD sensor array with 32 x32 pixels covering about 1 cm{sup 2} active area. The readout is implemented in a pixelated front-end ASIC suited for the readout of such arrays, matched to pixels of 280{mu}mx280{mu}m size. Every single channel features a fast transimpedance amplifier, a discriminator with locally adjustable threshold and two counters with high dynamic range and counting speed able to accumulate X-ray hits with no readout dead time. Additionally, the detector can be operated in list mode by time-stamping every single event with sub-nanosecond resolution. In a first phase of the project, a 4x4 pixel test module is built to validate the conceptual design of the detector. The XNAP project is briefly presented and the performance of the readout ASIC is discussed.

  9. Pixel readout ASIC for an APD based 2D X-ray hybrid pixel detector with sub-nanosecond resolution

    International Nuclear Information System (INIS)

    Thil, Ch.; Baron, A.Q.R.; Fajardo, P.; Fischer, P.; Graafsma, H.; Rueffer, R.

    2011-01-01

    The fast response and the short recovery time of avalanche photodiodes (APDs) in linear mode make those devices ideal for direct X-ray detection in applications requiring high time resolution or counting rate. In order to provide position sensitivity, the XNAP project aims at creating a hybrid pixel detector with nanosecond time resolution based on a monolithic APD sensor array with 32 x32 pixels covering about 1 cm 2 active area. The readout is implemented in a pixelated front-end ASIC suited for the readout of such arrays, matched to pixels of 280μmx280μm size. Every single channel features a fast transimpedance amplifier, a discriminator with locally adjustable threshold and two counters with high dynamic range and counting speed able to accumulate X-ray hits with no readout dead time. Additionally, the detector can be operated in list mode by time-stamping every single event with sub-nanosecond resolution. In a first phase of the project, a 4x4 pixel test module is built to validate the conceptual design of the detector. The XNAP project is briefly presented and the performance of the readout ASIC is discussed.

  10. Measurements on a prototype segmented Clover detector

    CERN Document Server

    Shepherd, S L; Cullen, D M; Appelbe, D E; Simpson, J; Gerl, J; Kaspar, M; Kleinböhl, A; Peter, I; Rejmund, M; Schaffner, H; Schlegel, C; France, G D

    1999-01-01

    The performance of a segmented Clover germanium detector has been measured. The segmented Clover detector is a composite germanium detector, consisting of four individual germanium crystals in the configuration of a four-leaf Clover, housed in a single cryostat. Each crystal is electrically segmented on its outer surface into four quadrants, with separate energy read-outs from nine crystal zones. Signals are also taken from the inner contact of each crystal. This effectively produces a detector with 16 active elements. One of the purposes of this segmentation is to improve the overall spectral resolution when detecting gamma radiation emitted following a nuclear reaction, by minimising Doppler broadening caused by the opening angle subtended by each detector element. Results of the tests with sources and in beam will be presented. The improved granularity of the detector also leads to an improved isolated hit probability compared with an unsegmented Clover detector. (author)

  11. Computational studies of BEGe detectors

    Energy Technology Data Exchange (ETDEWEB)

    Salathe, Marco [Max Planck Institut fuer Kernphysik, Heidelberg (Germany)

    2013-07-01

    The GERDA experiment searches for the neutrinoless double beta decay within the active volume of germanium detectors. Simulations of the physical processes within such detectors are vital to gain a better understanding of the measurements. The simulation procedure follows three steps: First it calculates the electric potential, next it simulates the electron and hole drift within the germanium crystal and finally it generates a corresponding signal. The GERDA collaboration recently characterized newly produced Broad Energy Germanium Detectors (BEGe) in the HADES underground laboratory in Mol, Belgium. A new pulse shape simulation library was established to examine the results of these measurements. The library has also proven to be a very powerful tool for other applications such as detector optimisation studies. The pulse shape library is based on ADL 3.0 (B. Bruyneel, B. Birkenbach, http://www.ikp.uni-koeln.de/research/agata/download.php) and m3dcr (D. Radford, http://radware.phy.ornl.gov/MJ/m3dcr).

  12. PantherPix hybrid pixel γ-ray detector for radio-therapeutic applications

    Science.gov (United States)

    Neue, G.; Benka, T.; Havránek, M.; Hejtmánek, M.; Janoška, Z.; Kafka, V.; Korchak, O.; Lednický, D.; Marčišovská, M.; Marčišovský, M.; Popule, J.; Şmarhák, J.; Şvihra, P.; Tomášek, L.; Vrba, V.; Konček, O.; Semmler, M.

    2018-02-01

    This work focuses on the design of a semiconductor pixelated γ-ray camera with a pixel size of 1 mm2. The cost of semiconductor manufacturing is mainly driven by economies of scale, which makes silicon the cheapest semiconductor material due to its widespread utilization. The energy of γ-photons used in radiation therapy are in a range, in which the dominant interaction mechanism is Compton scattering in every conceivable sensor material. Since the Compton scattering cross section is linearly dependent upon Z, it is less rewarding to utilize high Z sensor materials, than it is in the case of X-ray detectors (X-rays interact also via the photoelectric effect whose cross section scales proportional to Zn, where n is ≈ 4,5). For the stated reasons it was decided to use the low Z material silicon (Z = 14) despite its worse detection efficiency. The proposed detector is designed as a portal detector to be used in radiation cancer therapy. The purpose of the detector is to ensure correct patient alignment, spatial dose monitoring and to provide the feedback necessary for an emergency shutdown should the spatial dose rate profile deviate from the treatment plan. Radiation therapy equipment is complex and thus failure prone and the consequences of malfunction are often life threatening. High spatial resolution and high detection efficiency are not a high design priority. The detector design priorities are focused up on radiation hardness, robustness and the ability to cover a large area cost efficiently. The quintessential idea of the PanterPix detector exploits the relaxed spatial resolution requirement to achieve the stated goals. The detector is composed of submodules, each submodule consisting of a Si sensor with an array of fully depleted detection diodes and 8 miniature custom design readout ASICs collecting and measuring the minuscule charge packets generated due to ionization in the PN junctions.

  13. Radiation damage in semiconductor detectors

    International Nuclear Information System (INIS)

    Kraner, H.W.

    1981-12-01

    A survey is presented of the important damage-producing interactions in semiconductor detectors and estimates of defect numbers are made for MeV protons, neutrons and electrons. Damage effects of fast neutrons in germanium gamma ray spectrometers are given in some detail. General effects in silicon detectors are discussed and damage constants and their relationship to leakage current is introduced

  14. Two-Dimensional Spatial Imaging of Charge Transport in Germanium Crystals at Cryogenic Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Moffatt, Robert [Stanford Univ., CA (United States)

    2016-03-01

    In this dissertation, I describe a novel apparatus for studying the transport of charge in semiconductors at cryogenic temperatures. The motivation to conduct this experiment originated from an asymmetry observed between the behavior of electrons and holes in the germanium detector crystals used by the Cryogenic Dark Matter Search (CDMS). This asymmetry is a consequence of the anisotropic propagation of electrons in germanium at cryogenic temperatures. To better model our detectors, we incorporated this effect into our Monte Carlo simulations of charge transport. The purpose of the experiment described in this dissertation is to test those models in detail. Our measurements have allowed us to discover a shortcoming in our most recent Monte Carlo simulations of electrons in germanium. This discovery would not have been possible without the measurement of the full, two-dimensional charge distribution, which our experimental apparatus has allowed for the first time at cryogenic temperatures.

  15. X-ray imaging with photon counting hybrid semiconductor pixel detectors

    CERN Document Server

    Manolopoulos, S; Campbell, M; Snoeys, W; Heijne, Erik H M; Pernigotti, E; Raine, C; Smith, K; Watt, J; O'Shea, V; Ludwig, J; Schwarz, C

    1999-01-01

    Semiconductor pixel detectors, originally developed for particle physics experiments, have been studied as X-ray imaging devices. The performance of devices using the OMEGA 3 read-out chip bump-bonded to pixellated silicon semiconductor detectors is characterised in terms of their signal-to-noise ratio when exposed to 60 kVp X-rays. Although parts of the devices achieve values of this ratio compatible with the noise being photon statistics limited, this is not found to hold for the whole pixel matrix, resulting in the global signal-to-noise ratio being compromised. First results are presented of X-ray images taken with a gallium arsenide pixel detector bump-bonded to a new read-out chip, (MEDIPIX), which is a single photon counting read-out chip incorporating a 15-bit counter in every pixel. (author)

  16. Radiation hardness assessment of the charge-integrating hybrid pixel detector JUNGFRAU 1.0 for photon science

    Energy Technology Data Exchange (ETDEWEB)

    Jungmann-Smith, J. H., E-mail: jsmith@magnet.fsu.edu; Bergamaschi, A.; Brückner, M.; Dinapoli, R.; Greiffenberg, D.; Jaggi, A.; Maliakal, D.; Mayilyan, D.; Mezza, D.; Mozzanica, A.; Ramilli, M.; Ruder, Ch.; Schädler, L.; Schmitt, B.; Shi, X.; Tinti, G. [Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Cartier, S. [Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Institute for Biomedical Engineering, University and ETHZ, 8092 Zürich (Switzerland); Medjoubi, K. [Synchrotron Soleil, L’Orme des Merisiers, Saint-Aubin–BP 48, 91192 GIF-sur-Yvette Cedex (France)

    2015-12-15

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications in free electron lasers, particularly SwissFEL, and synchrotron light sources. JUNGFRAU is an automatic gain switching, charge-integrating detector which covers a dynamic range of more than 10{sup 4} photons of an energy of 12 keV with a good linearity, uniformity of response, and spatial resolving power. The JUNGFRAU 1.0 application-specific integrated circuit (ASIC) features a 256 × 256 pixel matrix of 75 × 75 μm{sup 2} pixels and is bump-bonded to a 320 μm thick Si sensor. Modules of 2 × 4 chips cover an area of about 4 × 8 cm{sup 2}. Readout rates in excess of 2 kHz enable linear count rate capabilities of 20 MHz (at 12 keV) and 50 MHz (at 5 keV). The tolerance of JUNGFRAU to radiation is a key issue to guarantee several years of operation at free electron lasers and synchrotrons. The radiation hardness of JUNGFRAU 1.0 is tested with synchrotron radiation up to 10 MGy of delivered dose. The effect of radiation-induced changes on the noise, baseline, gain, and gain switching is evaluated post-irradiation for both the ASIC and the hybridized assembly. The bare JUNGFRAU 1.0 chip can withstand doses as high as 10 MGy with minor changes to its noise and a reduction in the preamplifier gain. The hybridized assembly, in particular the sensor, is affected by the photon irradiation which mainly shows as an increase in the leakage current. Self-healing of the system is investigated during a period of 11 weeks after the delivery of the radiation dose. Annealing radiation-induced changes by bake-out at 100 °C is investigated. It is concluded that the JUNGFRAU 1.0 pixel is sufficiently radiation-hard for its envisioned applications at SwissFEL and synchrotron beam lines.

  17. The design of the detector and collimators for a hybrid scanner

    International Nuclear Information System (INIS)

    Vauramo, E.; Virjo, A.

    1977-01-01

    The hybrid scanner is a scanning device in which a long crystal with two or more photomultiplier (PM) tubes acts as a gamma camera along the crystal axis; the device acts as a linear scanner in a direction perpendicular to the crystal axis. A detailed analysis of the intrinsic resolution and uniformity is given for a two-PM-tube hybrid scanner (with one PM tube at each end) and the expressions derived should help the designer to choose the best crystal system. Collimation theory is discussed for the general hybrid scanner. Expressions and graphs are given to help in the design of a collimator with the best balance between the conflicting requirements of resolution, sensitivity, depth independence and freedom from artifacts (collimator holes may be seen in the image at high energy). Examples of practical collimators are given for energies of 80 to 140, 364, 511, 662 and 840 keV. (author)

  18. Development of high data readout rate pixel module and detector hybridization at Fermilab

    International Nuclear Information System (INIS)

    Zimmermann, Sergio

    2001-01-01

    This paper describes the baseline design and a variation of the pixel module to handle the data rate required for the BTeV experiment at Fermilab. The present prototype has shown good electrical performance characteristics. Indium bump bonding is proven to be capable of successful fabrication at 50 micron pitch on real detectors. For solder bumps at 50 micron pitch, much better results have been obtained with the fluxless PADS processed detectors. The results are adequate for our needs and our tests have validated it as a viable technology

  19. Design and realization of a fast low noise electronics for a hybrid pixel X-ray detector dedicated to small animal imaging

    International Nuclear Information System (INIS)

    Chantepie, B.

    2008-12-01

    Since the invention of computerized tomography (CT), charge integration detector were widely employed for X-ray biomedical imaging applications. Nevertheless, other options exist. A new technology of direct detection using semiconductors has been developed for high energy physics instrumentation. This new technology, called hybrid pixel detector, works in photon counting mode and allows for selecting the minimum energy of the counted photons. The ImXgam research team at CPPM develops the PIXSCAN demonstrator, a CT-scanner using the hybrid pixel detector XPAD. The aim of this project is to evaluate the improvement in image quality and in dose delivered during X-ray examinations of a small animal. After a first prototype of a hybrid pixel detector XPAD1 proving the feasibility of the project, a complete imager XPAD2 was designed and integrated in the PIXSCAN demonstrator. Since then, with the evolution of microelectronic industry, important improvements are conceivable. To reducing the size of pixels and to improving the energy resolution of detectors, a third design XPAD3 was conceived and will be soon integrated in a second generation of PIXSCAN demonstrator. In this project, my thesis work consisted in taking part to the design of the detector readout electronics, to the characterization of the chips and of the hybrid pixel detectors, and also to the definition of a auto-zeroing architecture for pixels. The first and second chapters present X-ray medical imaging and particle detection with semi-conductors and its modelling. The third chapter deals with the specifications of electronic circuits for imaging applications first for analog pixels then for digital pixels and describes the general architecture of the integrated circuits. The validation tests are presented in the fourth chapter while the last chapter gives an account of expected changes in pixel electronics

  20. A GEANT4 based simulation for pixelated X-ray hybrid detectors

    International Nuclear Information System (INIS)

    Marinho, F.; Akiba, K.

    2015-01-01

    In this letter we present a detailed Monte Carlo approach to simulate pixelated detectors for X-ray applications. It allows us to fully characterize quantities such as interaction probability and reconstructed energy deposits according to beam energy as to evaluate energy and position resolution for comparisons with experimental results. The implementation and use of Monte Carlo truth information is also discussed

  1. Hall mobility of free charge carriers in highly compensated p-Germanium

    International Nuclear Information System (INIS)

    Gavrilyuk, V.Yi.; Kirnas, Yi.G.; Balakyin, V.D.

    2000-01-01

    Hall mobility of free charge carriers in initial detectors Ge (Ga) is studied. It is established that an increase in the compensation factor results in the enlargement of Hall mobility in germanium highly compensated by introduction of Li ions during their drift in an electrical field

  2. The TDCpix readout ASIC: A 75 ps resolution timing front-end for the NA62 Gigatracker hybrid pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    Kluge, A., E-mail: alexander.kluge@cern.ch; Aglieri Rinella, G.; Bonacini, S.; Jarron, P.; Kaplon, J.; Morel, M.; Noy, M.; Perktold, L.; Poltorak, K.

    2013-12-21

    The TDCpix is a novel pixel readout ASIC for the NA62 Gigatracker detector. NA62 is a new experiment being installed at the CERN Super Proton Synchrotron. Its Gigatracker detector shall provide on-beam tracking and time stamping of individual particles with a time resolution of 150 ps rms. It will consist of three tracking stations, each with one hybrid pixel sensor. The peak flow of particles crossing the detector modules reaches 1.27 MHz/mm{sup 2} for a total rate of about 0.75 GHz. Ten TDCpix chips will be bump-bonded to every silicon pixel sensor. Each chip shall perform time stamping of 100 M particle hits per second with a detection efficiency above 99% and a timing accuracy better than 200 ps rms for an overall three-station-setup time resolution of better than 150 ps. The TDCpix chip has been designed in a 130 nm CMOS technology. It will feature 45×40 square pixels of 300×300μm{sup 2} and a complex End of Column peripheral region including an array of TDCs based on DLLs, four high speed serializers, a low-jitter PLL, readout and control circuits. This contribution will describe the complete design of the final TDCpix ASIC. It will discuss design choices, the challenges faced and some of the lessons learned. Furthermore, experimental results from the testing of circuit prototypes will be presented. These demonstrate the achievement of key performance figures such as a time resolution of the processing chain of 75 ps rms with a laser sent to the center of the pixel and the capability of time stamping charged particles with an overall resolution below 200 ps rms. -- Highlights: • Feasibility demonstration of a silicon pixel detector with sub-ns time tagging capability. • Demonstrator detector assembly with a time resolution of 75 ps RMS with laser charge injection; 170 ps RMS with particle beam. • Design of trigger-less TDCpix ASIC with 1800 pixels, 720 TDC channels and 4 3.2 Gbit/s serializers.

  3. Harmonic Lattice Dynamics of Germanium

    Energy Technology Data Exchange (ETDEWEB)

    Nelin, G

    1974-07-01

    The phonon dispersion relations of the DELTA-, LAMBDA-, and SIGMA-directions of germanium at 80 K are analysed in terms of current harmonic lattice dynamical models. On the basis of this experience, a new model is proposed which gives a unified account of the strong points of the previous models. The principal elements of the presented theory are quasiparticle bond charges combined with a valence force field.

  4. Harmonic Lattice Dynamics of Germanium

    International Nuclear Information System (INIS)

    Nelin, G.

    1974-01-01

    The phonon dispersion relations of the Δ-, Λ-, and Σ-directions of germanium at 80 K are analysed in terms of current harmonic lattice dynamical models. On the basis of this experience, a new model is proposed which gives a unified account of the strong points of the previous models. The principal elements of the presented theory are quasiparticle bond charges combined with a valence force field

  5. Recent advances with a hybrid micro-pattern gas detector operated in low pressure H2 and He, for AT-TPC applications

    Directory of Open Access Journals (Sweden)

    Cortesi Marco

    2018-01-01

    Full Text Available In view of a possible application as a charge-particle track readout for an Active-Target Time Projection Chamber (AT-TPC, the operational properties and performances of a hybrid Micro-Pattern Gaseous Detector (MPGD were investigated in pure low-pressure Hydrogen (H2 and Helium (He. The detector consists of a MICROMEsh GAseous Structure (MICROMEGAS coupled to a two-cascade THick Gaseous Electron Multiplier (THGEM as a pre-amplification stage. This study reports the effective gain dependence of the hybrid-MPGD at relevant pressure (in the range of 200-760 torr for different detector arrangements. The results of this work are relevant in the field of avalanche mechanism in low-pressure, low-mass noble gases, in particularly for applications of MPGD end-cap readout for active-target Time Projection Chambers (TPC in the field of nuclear physics and nuclear astrophysics.

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

    International Nuclear Information System (INIS)

    Hall, R.N.

    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 0 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 and subsequently diffusing some of the lithium back out through the surface to create a deep p-n junction. Coaxial germanium detectors comprising deep p-n junctions are produced by the lithium diffusion process

  7. Development of a hybrid MSGC detector for thermal neutron imaging with a MHz data acquisition and histogramming system

    CERN Document Server

    Gebauer, B; Richter, G; Levchanovsky, F V; Nikiforov, A

    2001-01-01

    For thermal neutron imaging at the next generation of high-flux pulsed neutron sources a large area and fourfold segmented, hybrid, low-pressure, two-dimensional position sensitive, microstrip gas chamber detector, fabricated in a multilayer technology on glass substrates, is presently being developed, which utilizes a thin composite sup 1 sup 5 sup 7 Gd/CsI neutron converter. The present article focusses on the readout scheme and the data acquisition (DAQ) system. For position encoding, interpolating and fast multihit delay line based electronics is applied with up to eightfold sub-segmentation per geometrical detector segment. All signals, i.e. position, time-of-flight and pulse-height signals, are fed into deadtime-less 8-channel multihit TDC chips with 120 ps LSB via constant fraction and time-over-threshold discriminators, respectively. The multihit capability is utilized to raise the count rate limit in combination with a sum check algorithm for disentangling pulses from different events. The first vers...

  8. Review of the hybrid photo diode tube (HPD) an advanced light detector for physics

    International Nuclear Information System (INIS)

    Anzivino, G.; Baillon, P.; Benetti, P.; Boskma, L.; Burger, P.; Contin, A.; DeSalvo, R.; Gorodetzky, P.; Grassi, D.; Hao, W.; He, H.; Liu, L.; Lundin, M.; Mondardini, M.R.; Paolucci, S.; Rossella, M.; Santiard, J.C.; Schomaker, R.; You, K.; Wang, K.; Wang, Y.; Xia, X.; Xu, C.; Yang, C.; Zhao, M.

    1995-01-01

    The HPD is a nonmultiplicative light detector with typical gain of 1000 to 5000. Its development project, mainly supported by the CERN LAA project and by the INFN group V, was originally intended to find a replacement for the photo multiplier (PM) tubes for scintillating fibre calorimeter readout. After five years of development the HPD has become a versatile light detector, commercially available for everyday use, that can outperform PM tubes in photon counting efficiency and resolution, multi tesla magnetic field operation, uniformity of response, fast pulse dynamic range, and gain stability. The HPD has also a wide edge on PMs on pixelization potential and it is getting more and more competitive on timing properties. A review of the HPD performances and its latest advances are reported. (orig.)

  9. Review of the hybrid photo diode tube (HPD) an advanced light detector for physics

    Energy Technology Data Exchange (ETDEWEB)

    Anzivino, G. [Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati; Arnaudon, H. [Universite` L. Pasteur, 4, rue B. Pascal, F-67000 Strasbourg (France); Baillon, P. [CERN, CH-1211 Geneva 23 (Switzerland); Benetti, P. [INFN Sezione di Pavia and Universita` di Pavia, via A. Bassi 6, I-27100 Pavia (Italy); Boskma, L. [DEP, P.O. box 60, NL-9300 AB Roden (Netherlands); Burger, P. [Canberra, Lammerdries 25, B-2250 Olen (Belgium); Contin, A. [CERN, CH-1211 Geneva 23 (Switzerland)]|[INFN Sezione di Bologna and Universita` di Bologna, via Irnerio 46, I-40126 Bologna (Italy); DeSalvo, R. [CERN, CH-1211 Geneva 23 (Switzerland); Gorodetzky, P. [CNRS, Strasbourg (France); Grassi, D. [INFN Sezione di Pavia and Universita` di Pavia, via A. Bassi 6, I-27100 Pavia (Italy); Hao, W. [IHEP, Beijing (China); He, H. [IHEP, Beijing (China); Liu, L. [IHEP, Beijing (China); Lundin, M. [Cornell University, Ithaca, NY 14853 (United States); Mondardini, M.R. [Cornell University, Ithaca, NY 14853 (United States); Paolucci, S. [INFN Sezione di Pavia and Universita` di Pavia, via A. Bassi 6, I-27100 Pavia (Italy); Rossella, M. [INFN Sezione di Pavia and Universita` di Pavia, via A. Bassi 6, I-27100 Pavia (Italy); Santiard, J.C. [CERN, CH-1211 Geneva 23 (Switzerland); Schomaker, R. [DEP, P.O. box 60, NL-9300 AB Roden (Netherlands); You, K. [IHEP, Beijing (China); Wang, K. [IHEP, Beijing (China); Wang, Y. [IHEP, Beijing (China); Xia, X. [IHEP, Beijing (China); Xu, C. [IHEP, Beijing (China); Yang, C. [IHEP, Beijing (China); Zhao, M. [IHEP, Beijing (China)

    1995-11-01

    The HPD is a nonmultiplicative light detector with typical gain of 1000 to 5000. Its development project, mainly supported by the CERN LAA project and by the INFN group V, was originally intended to find a replacement for the photo multiplier (PM) tubes for scintillating fibre calorimeter readout. After five years of development the HPD has become a versatile light detector, commercially available for everyday use, that can outperform PM tubes in photon counting efficiency and resolution, multi tesla magnetic field operation, uniformity of response, fast pulse dynamic range, and gain stability. The HPD has also a wide edge on PMs on pixelization potential and it is getting more and more competitive on timing properties. A review of the HPD performances and its latest advances are reported. (orig.).

  10. Superconductivity of tribolayers formed on germanium by friction between germanium and lead

    Energy Technology Data Exchange (ETDEWEB)

    Dukhovskoi, A.; Karapetyan, S.S.; Morozov, Y.G.; Onishchenko, A.S.; Petinov, V.I.; Ponomarev, A.N.; Silin, A.A.; Stepanov, B.M.; Tal' roze, V.L.

    1978-04-05

    A superconducting state was observed for the first time in tribolayers of germanium produced by friction of germanium with lead at 42 K. The maximum value of T/sub c/ obtained in the experiment was 19 K, which is much higher than T/sub c/ of bulk lead itself or of lead films sputtered on germanium.

  11. Positron imaging with multiwire proportional chamber-gamma converter hybrid detectors

    International Nuclear Information System (INIS)

    Chu, D.Y.H.

    1976-09-01

    A large area positron camera was developed using multiwire proportional chambers as detectors and electromagnetic delay lines for coordinate readout. Honeycomb structured gamma converters made of lead are coupled to the chambers for efficient gamma detection and good spatial resolution. Two opposing detectors, each having a sensitive area of 48 cm x 48 cm, are operated in coincidence for the detection of annihilation gammas (511 keV) from positron emitters. Detection efficiency of 4.2 percent per detector and spatial resolution of 6 to 7 mm FWHM at the mid-plane were achieved. The present camera operates at a maximum count rate of 24 K counts/min, limited by accidental coincidence. The theory for the gamma converter is presented along with a review of the operation of the multiwire proportional chamber and delay line readout. Calculated gamma converter efficiencies are compared with the measured results using a prototype test chamber. The characteristics of the positron camera system is evaluated, and the performance is shown to be consistent with calculation

  12. Liquid-helium scintillation detection with germanium photodiodes

    International Nuclear Information System (INIS)

    Luke, P.N.; Haller, E.E.; Steiner, H.M.

    1982-05-01

    Special high-purity germanium photodiodes have been developed for the direct detection of vacuum ultraviolet scintillations in liquid helium. The photodiodes are immersed in the liquid helium, and scintillations are detected through one of the bare sides of the photodiodes. Test results with scintillation photons produced by 5.3-MeV α particles are presented. The use of these photodiodes as liquid-helium scintillation detectors may offer substantial improvements over the alternate detection method requiring the use of wavelength shifters and photomultiplier tubes

  13. Point defect engineering strategies to retard phosphorous diffusion in germanium

    KAUST Repository

    Tahini, H. A.; Chroneos, Alexander I.; Grimes, Robin W.; Schwingenschlö gl, Udo; Bracht, Hartmut A.

    2013-01-01

    The diffusion of phosphorous in germanium is very fast, requiring point defect engineering strategies to retard it in support of technological application. Density functional theory corroborated with hybrid density functional calculations are used to investigate the influence of the isovalent codopants tin and hafnium in the migration of phosphorous via the vacancy-mediated diffusion process. The migration energy barriers for phosphorous are increased significantly in the presence of oversized isovalent codopants. Therefore, it is proposed that tin and in particular hafnium codoping are efficient point defect engineering strategies to retard phosphorous migration. © the Owner Societies 2013.

  14. Novel Hybrid CMOS X-ray Detector Developments for Future Large Area and High Resolution X-ray Astronomy Missions

    Science.gov (United States)

    Falcone, Abe

    In the coming years, X-ray astronomy will require new soft X-ray detectors that can be read very quickly with low noise and can achieve small pixel sizes over a moderately large focal plane area. These requirements will be present for a variety of X-ray missions that will attempt to address science that was highly ranked by the 2010 Decadal Survey, including missions with science that overlaps with that of IXO and Athena, as well as other missions addressing science topics beyond those of IXO and Athena. An X-ray Surveyor mission was recently chosen by NASA for study by a Science & Technology Definition Team (STDT) so it can be considered as an option for an upcom-ing flagship mission. A mission such as this was endorsed by the NASA long term planning document entitled "Enduring Quests, Daring Visions," and a detailed description of one possible reali-zation of such a mission has been referred to as SMART-X, which was described in a recent NASA RFI response. This provides an example of a future mission concept with these requirements since it has high X-ray throughput and excellent spatial resolution. We propose to continue to modify current active pixel sensor designs, in particular the hybrid CMOS detectors that we have been working with for several years, and implement new in-pixel technologies that will allow us to achieve these ambitious and realistic requirements on a timeline that will make them available to upcoming X-ray missions. This proposal is a continuation of our program that has been work-ing on these developments for the past several years. The first 3 years of the program led to the development of a new circuit design for each pixel, which has now been shown to be suitable for a larger detector array. The proposed activity for the next four years will be to incorporate this pixel design into a new design of a full detector array (2k×2k pixels with digital output) and to fabricate this full-sized device so it can be thoroughly tested and

  15. Atomic ionization of germanium by neutrinos from an ab initio approach

    International Nuclear Information System (INIS)

    Chen, Jiunn-Wei; Chi, Hsin-Chang; Huang, Keh-Ning; Liu, C.-P.; Shiao, Hao-Tse; Singh, Lakhwinder; Wong, Henry T.; Wu, Chih-Liang; Wu, Chih-Pan

    2014-01-01

    An ab initio calculation of atomic ionization of germanium by neutrinos was carried out in the framework of multiconfiguration relativistic random phase approximation and benchmarked by related atomic structure and photoabsorption data. This improves over the conventional approach based on scattering off free electrons whose validity at sub-keV energy transfer is questionable. Limits on neutrino magnetic moments are derived using reactor neutrino data taken with low threshold germanium detectors. Future applications of these atomic techniques will greatly reduce the atomic uncertainties in low-energy neutrino and dark matter detections.

  16. Theoretical Investigations of the Hexagonal Germanium Carbonitride

    Directory of Open Access Journals (Sweden)

    Xinhai Yu

    2018-04-01

    Full Text Available The structural, mechanical, elastic anisotropic, and electronic properties of hexagonal germanium carbonitride (h-GeCN are systematically investigated using the first-principle calculations method with the ultrasoft pseudopotential scheme in the frame of generalized gradient approximation in the present work. The h-GeCN are mechanically and dynamically stable, as proved by the elastic constants and phonon spectra, respectively. The h-GeCN is brittle because the ratio B/G and Poisson’s ratio v of the h-GeCN are less than 1.75 and 0.26, respectively. For h-GeCN, from brittleness to ductility, the transformation pressures are 5.56 GPa and 5.63 GPa for B/G and Poisson’s ratio v, respectively. The h-GeCN exhibits the greater elastic anisotropy in Young’s modulus and the sound velocities. In addition, the calculated band structure of h-GeCN reveals that there is no band gap for h-GeCN with the HSE06 hybrid functional, so the h-GeCN is metallic.

  17. Test beam analysis of ultra-thin hybrid pixel detector assemblies with Timepix readout ASICs

    CERN Document Server

    Alipour Tehrani, Niloufar; Dannheim, Dominik; Firu, Elena; Kulis, Szymon; Redford, Sophie; Sicking, Eva

    2016-01-01

    The requirements for the vertex detector at the proposed Compact Linear Collider imply a very small material budget: less than 0.2% of a radiation length per detection layer including services and mechanical supports. We present here a study using Timepix readout ASICs hybridised to pixel sensors of 50 − 500 μm thickness, including assemblies with 100 μm thick sensors bonded to thinned 100μm thick ASICs. Sensors from three producers (Advacam, Micron Semiconductor Ltd, Canberra) with different edge termination technologies (active edge, slim edge) were bonded to Timepix ASICs. These devices were characterised with the EUDET telescope at the DESY II test beam using 5.6 GeV electrons. Their performance for the detection and tracking of minimum ionising particles was evaluated in terms of charge sharing, detection efficiency, single-point resolution and energy deposition.

  18. The MAJORANA DEMONSTRATOR: A Search for Neutrinoless Double-beta Decay of Germanium-76

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, Alexis G.; Aguayo, Estanislao; Avignone, F. T.; Zhang, C.; Back, Henning O.; Barabash, Alexander S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Collar, J. I.; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Leon, Jonathan D.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor M.; Giovanetti, G. K.; Green, M.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, Reyco; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, Mark; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; LaRoque, B. H.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Phillips, D.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Sobolev, V.; Steele, David; Strain, J.; Thomas, K.; Timkin, V.; Tornow, Werner; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Wolfe, B. A.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2012-09-28

    The observation of neutrinoless double-beta decay would determine whether the neutrino is a Majorana particle and provide information on the absolute scale of neutrino mass. The MAJORANA Collaboration is constructing the DEMONSTRATOR, an array of germanium detectors, to search for neutrinoless double-beta decay of 76Ge. The DEMONSTRATOR will contain 40 kg of germanium; up to 30 kg will be enriched to 86% in 76Ge. The DEMONSTRATOR will be deployed deep underground in an ultra-low-background shielded environment. Operation of the DEMONSTRATOR aims to determine whether a future tonne-scale germanium experiment can achieve a background goal of one count per tonne-year in a 4-keV region of interest around the 76Ge neutrinoless double-beta decay Q-value of 2039 keV.

  19. Flip chip assembly of thinned chips for hybrid pixel detector applications

    CERN Document Server

    Fritzsch, T; Woehrmann, M; Rothermund, M; Huegging, F; Ehrmann, O; Oppermann, H; Lang, K.D

    2014-01-01

    There is a steady trend to ultra-thin microelectronic devices. Especially for future particle detector systems a reduced readout chip thickness is required to limit the loss of tracking precision due to scattering. The reduction of silicon thickness is performed at wafer level in a two-step thinning process. To minimize the risk of wafer breakage the thinned wafer needs to be handled by a carrier during the whole process chain of wafer bumping. Another key process is the flip chip assembly of thinned readout chips onto thin sensor tiles. Besides the prevention of silicon breakage the minimization of chip warpage is one additional task for a high yield and reliable flip chip process. A new technology using glass carrier wafer will be described in detail. The main advantage of this technology is the combination of a carrier support during wafer processing and the chip support during flip chip assembly. For that a glass wafer is glue-bonded onto the backside of the thinned readout chip wafer. After the bump depo...

  20. In situ micro-focused X-ray beam characterization with a lensless camera using a hybrid pixel detector

    International Nuclear Information System (INIS)

    Kachatkou, Anton; Marchal, Julien; Silfhout, Roelof van

    2014-01-01

    Position and size measurements of a micro-focused X-ray beam, using an X-ray beam imaging device based on a lensless camera that collects radiation scattered from a thin foil placed in the path of the beam at an oblique angle, are reported. Results of studies on micro-focused X-ray beam diagnostics using an X-ray beam imaging (XBI) instrument based on the idea of recording radiation scattered from a thin foil of a low-Z material with a lensless camera are reported. The XBI instrument captures magnified images of the scattering region within the foil as illuminated by the incident beam. These images contain information about beam size, beam position and beam intensity that is extracted during dedicated signal processing steps. In this work the use of the device with beams for which the beam size is significantly smaller than that of a single detector pixel is explored. The performance of the XBI device equipped with a state-of-the-art hybrid pixel X-ray imaging sensor is analysed. Compared with traditional methods such as slit edge or wire scanners, the XBI micro-focused beam characterization is significantly faster and does not interfere with on-going experiments. The challenges associated with measuring micrometre-sized beams are described and ways of optimizing the resolution of beam position and size measurements of the XBI instrument are discussed

  1. Hydrogen concentration and distribution in high-purity germanium crystals

    International Nuclear Information System (INIS)

    Hansen, W.L.; Haller, E.E.; Luke, P.N.

    1981-10-01

    High-purity germanium crystals used for making nuclear radiation detectors are usually grown in a hydrogen ambient from a melt contained in a high-purity silica crucible. The benefits and problems encountered in using a hydrogen ambient are reviewed. A hydrogen concentration of about 2 x 10 15 cm -3 has been determined by growing crystals in hydrogen spiked with tritium and counting the tritium β-decays in detectors made from these crystals. Annealing studies show that the hydrogen is strongly bound, either to defects or as H 2 with a dissociation energy > 3 eV. This is lowered to 1.8 eV when copper is present. Etching defects in dislocation-free crystals grown in hydrogen have been found by etch stripping to have a density of about 1 x 10 7 cm -3 and are estimated to contain 10 8 H atoms each

  2. Background recognition in Ge detectors by pulse shape analysis

    International Nuclear Information System (INIS)

    Petry, F.; Piepke, A.; Strecker, H.; Klapdor-Kleingrothaus, H.V.; Balysh, A.; Belyaev, S.T.; Demehin, A.; Gurov, A.; Kondratenko, I.; Kotel'nikov, D.; Lebedev, V.I.; Landis, D.; Madden, N.; Pehl, R.H.

    1993-01-01

    A method of event identification that distinguishes single and multiple-site events by determining the number of interactions in a high purity germanium detector is reported. The selectivity of the method has been experimentally verified. (orig.)

  3. Status and problems of semiconductor detectors

    International Nuclear Information System (INIS)

    Walton, J.T.; Goulding, F.S.; Haller, E.E.; Pehl, R.H.

    1981-03-01

    A brief review is given of the types of silicon and germanium detectors used or presently being developed for nuclear experiments. Large-area silicon and germanium detector telescopes for use in long-range particle detection and identification are emphasized. Large area position-sensitive detectors are also described. Some results are presented regarding radiation damage and damage repair by annealing. Evidence is also presented for the importance of producing large area silicon crystals of adequate quality to reduce trapping problems to negligible proportions

  4. Status and problems of semiconductor detectors

    Energy Technology Data Exchange (ETDEWEB)

    Walton, J.T.; Goulding, F.S.; Haller, E.E.; Pehl, R.H.

    1981-03-01

    A brief review is given of the types of silicon and germanium detectors used or presently being developed for nuclear experiments. Large-area silicon and germanium detector telescopes for use in long-range particle detection and identification are emphasized. Large area position-sensitive detectors are also described. Some results are presented regarding radiation damage and damage repair by annealing. Evidence is also presented for the importance of producing large area silicon crystals of adequate quality to reduce trapping problems to negligible proportions.

  5. The Design and Implementation in $0.13\\mu m$ CMOS of an Algorithm Permitting Spectroscopic Imaging with High Spatial Resolution for Hybrid Pixel Detectors

    CERN Document Server

    Ballabriga, Rafael; Vilasís-Cardona, Xavier

    2009-01-01

    Advances in pixel detector technology are opening up new possibilities in many fields of science. Modern High Energy Physics (HEP) experiments use pixel detectors in tracking systems where excellent spatial resolution, precise timing and high signal-to-noise ratio are required for accurate and clean track reconstruction. Many groups are working worldwide to adapt the hybrid pixel technology to other fields such as medical X-ray radiography, protein structure analysis or neutron imaging. The Medipix3 chip is a 256x256 channel hybrid pixel detector readout chip working in Single Photon Counting Mode. It has been developed with a new front-end architecture aimed at eliminating the spectral distortion produced by charge diffusion in highly segmented semiconductor detectors. In the new architecture neighbouring pixels communicate with one another. Charges can be summed event-by-event and the incoming quantum can be assigned as a single hit to the pixel with the biggest charge deposit. In the case where incoming X-...

  6. Zone refining high-purity germanium

    International Nuclear Information System (INIS)

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

    1977-10-01

    The effects of various parameters on germanium purification by zone refining have been examined. These parameters include the germanium container and container coatings, ambient gas and other operating conditions. Four methods of refining are presented which reproducibly yield 3.5 kg germanium ingots from which high purity (vertical barN/sub A/ - N/sub D/vertical bar less than or equal to2 x 10 10 cm -3 ) single crystals can be grown. A qualitative model involving binary and ternary complexes of Si, O, B, and Al is shown to account for the behavior of impurities at these low concentrations

  7. Measurements of gamma (γ)-emitting radionuclides with a high-purity germanium detector: the methods and reliability of our environmental assessments on the Fukushima 1 Nuclear Power Plant accident.

    Science.gov (United States)

    Mimura, Tetsuro; Mimura, Mari; Komiyama, Chiyo; Miyamoto, Masaaki; Kitamura, Akira

    2014-01-01

    The severe accident of Fukushima 1 Nuclear Power Plant due to the Tohoku Region Pacific Coast Earthquake in 11 March 2011 caused wide contamination and pollution by radionuclides in Fukushima and surrounding prefectures. In the current JPR symposium, a group of plant scientists attempted to examine the impact of the radioactive contamination on wild and cultivated plants. Measurements of gamma (γ) radiation from radionuclides in "Fukushima samples", which we called and collected from natural and agricultural areas in Fukushima prefecture were mostly done with a high-purity Ge detector in the Graduate School of Maritime Sciences, Kobe University. In this technical note, we describe the methods of sample preparation and measurements of radioactivity of the samples and discuss the reliability of our data in regards to the International Atomic Energy Agency (IAEA) Interlaboratory comparisons and proficiency test (IAEA proficiency test).

  8. A fitting algorithm based on simulated annealing techniques for efficiency calibration of HPGe detectors using different mathematical functions

    Energy Technology Data Exchange (ETDEWEB)

    Hurtado, S. [Servicio de Radioisotopos, Centro de Investigacion, Tecnologia e Innovacion (CITIUS), Universidad de Sevilla, Avda. Reina Mercedes s/n, 41012 Sevilla (Spain)], E-mail: shurtado@us.es; Garcia-Leon, M. [Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Fisica, Universidad de Sevilla, Aptd. 1065, 41080 Sevilla (Spain); Garcia-Tenorio, R. [Departamento de Fisica Aplicada II, E.T.S.A. Universidad de Sevilla, Avda, Reina Mercedes 2, 41012 Sevilla (Spain)

    2008-09-11

    In this work several mathematical functions are compared in order to perform the full-energy peak efficiency calibration of HPGe detectors using a 126cm{sup 3} HPGe coaxial detector and gamma-ray energies ranging from 36 to 1460 keV. Statistical tests and Monte Carlo simulations were used to study the performance of the fitting curve equations. Furthermore the fitting procedure of these complex functional forms to experimental data is a non-linear multi-parameter minimization problem. In gamma-ray spectrometry usually non-linear least-squares fitting algorithms (Levenberg-Marquardt method) provide a fast convergence while minimizing {chi}{sub R}{sup 2}, however, sometimes reaching only local minima. In order to overcome that shortcoming a hybrid algorithm based on simulated annealing (HSA) techniques is proposed. Additionally a new function is suggested that models the efficiency curve of germanium detectors in gamma-ray spectrometry.

  9. Solution synthesis of germanium nanocrystals

    Science.gov (United States)

    Gerung, Henry [Albuquerque, NM; Boyle, Timothy J [Kensington, MD; Bunge, Scott D [Cuyahoga Falls, OH

    2009-09-22

    A method for providing a route for the synthesis of a Ge(0) nanometer-sized material from. A Ge(II) precursor is dissolved in a ligand heated to a temperature, generally between approximately 100.degree. C. and 400.degree. C., sufficient to thermally reduce the Ge(II) to Ge(0), where the ligand is a compound that can bond to the surface of the germanium nanomaterials to subsequently prevent agglomeration of the nanomaterials. The ligand encapsulates the surface of the Ge(0) material to prevent agglomeration. The resulting solution is cooled for handling, with the cooling characteristics useful in controlling the size and size distribution of the Ge(0) materials. The characteristics of the Ge(II) precursor determine whether the Ge(0) materials that result will be nanocrystals or nanowires.

  10. Compound Semiconductor Radiation Detectors

    CERN Document Server

    Owens, Alan

    2012-01-01

    Although elemental semiconductors such as silicon and germanium are standard for energy dispersive spectroscopy in the laboratory, their use for an increasing range of applications is becoming marginalized by their physical limitations, namely the need for ancillary cooling, their modest stopping powers, and radiation intolerance. Compound semiconductors, on the other hand, encompass such a wide range of physical and electronic properties that they have become viable competitors in a number of applications. Compound Semiconductor Radiation Detectors is a consolidated source of information on all aspects of the use of compound semiconductors for radiation detection and measurement. Serious Competitors to Germanium and Silicon Radiation Detectors Wide-gap compound semiconductors offer the ability to operate in a range of hostile thermal and radiation environments while still maintaining sub-keV spectral resolution at X-ray wavelengths. Narrow-gap materials offer the potential of exceeding the spectral resolutio...

  11. Hybrid PET/MRI insert: B0 field optimization by applying active and passive shimming on PET detector level

    Energy Technology Data Exchange (ETDEWEB)

    Wehner, Jakob [Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen (Germany); Weissler, Bjoern [Philips Research Europe, Aachen (Germany); Schulz, Volkmar [Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen (Germany); Philips Research Europe, Aachen (Germany)

    2014-07-29

    Combining PET and MRI into a hybrid device is challenging since both systems might influence each other. A typical interference problem of such a combined device is the distortion of the MRI’s B{sub 0} field distribution due to the material brought inside the MRI’s FOV which is in particular challenging for small-bore PET-systems. High field homogeneity is needed for a good MRI acquisition in general as well as in certain applications. Typically, active shimming using dedicated coils is applied to improve the field homogeneity. However, these techniques are limited especially for localized distortion profiles with higher-order characteristics caused by PET/MRI inserts. As a consequence, we are exploring the potential application of shimming on PET detector level (for the Hyperion-II{sup D} PET/MRI insert), meaning that the distortion profile caused by PET modules is compensated using additional magnetic materials (passive shimming) and DC coils (active shimming). To explore the technique, B{sub 0} field measurements have been performed using a whole-body phantom in combination with the MRI body coil. An FFE sequence was used to measure distortion maps of DC loops and small magnetic objects (capacitors, ferrites). These distortion maps served as input for a software framework which has been written to perform the field optimization. The implementation was verified by measurements and fits were performed to extract characteristic parameters of the tested objects. Finally, the implemented software framework was used to homogenize a measured distortion map produced by a single PET module by superimposing distortion corrections from additional simulated materials. The resulting superimposed distortion map showed a significantly improved B{sub 0} field map quality (reduced spectral width and improved homogeneity). The simulated susceptibility distribution will be applied on PET module level and tested in experiments. Results and details about this study will be

  12. Metal induced crystallization of silicon germanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gjukic, M.

    2007-05-15

    In the framework of this thesis the applicability of the aluminium-induced layer exchange on binary silicon germanium alloys was studied. It is here for the first time shown that polycrstalline silicon-germanium layers can be fabricated over the whole composition range by the aluminium-induced layer exchange. The experimental results prove thet the resulting material exhibits a polycrystalline character with typocal grain sizes of 10-100 {mu}m. Raman measurements confirm that the structural properties of the resulting layers are because of the large crystallites more comparable with monocrystalline than with nano- or microcrystalline silicon-germanium. The alloy ratio of the polycrystalline layer correspondes to the chemical composition of the amorphous starting layer. The polycrystalline silicon-germanium layers possess in the range of the interband transitions a reflection spectrum, as it is otherwise only known from monocrystalline reference layers. The improvement of the absorption in the photovoltaically relevant spectral range aimed by the application of silicon-germanium could be also proved by absorption measurments. Strongly correlated with the structural properties of the polycrystalline layers and the electronic band structure resulting from this are beside the optical properties also the electrical properties of the material, especially the charge-carrier mobility and the doping concentration. For binary silicon-germanium layers the hole concentration of about 2 x 10{sup 18} cm{sup -3} for pure silicon increrases to about 5 x 10{sup 20} cm{sub -3} for pure germanium. Temperature-resolved measurements were applied in order to detect doping levels respectively semiconductor-metal transitions. In the last part of the thesis the hydrogen passivation of polycrystalline thin silicon-germanium layers, which were fabricated by means of aluminium-induced layer exchange, is treated.

  13. Keeping the Background Low: Production and Testing of the GERDA Phase II Detectors

    International Nuclear Information System (INIS)

    Hemmer, Sabine

    2013-06-01

    The Germanium Detector Array (GERDA) experiment at the INFN Laboratori Nazionali del Gran Sasso searches for neutrinoless double beta decay of 76 Ge. The first phase using ∼15 kg of coaxial germanium detectors is ongoing. In a second phase, additional ∼20 kg of newly produced Broad Energy Germanium (BEGe) detectors will be deployed. To limit the generation of cosmogenically induced radioisotopes, the exposure of the germanium to cosmic radiation during the detector production and testing was minimized. An acceptance and characterization campaign of the newly produced detectors was carried out at the HEROICA facility in the HADES underground laboratory in Mol, Belgium. An overview over the complete production process, from isotopic enrichment of the material to the detector testing protocol, is given. (authors)

  14. An ultralow background germanium gamma-ray spectrometer

    International Nuclear Information System (INIS)

    Reeves, R.H.; Brodzinski, R.L.; Hensley, W.K.; Ryge, P.

    1984-01-01

    The monitoring of minimum detectable activity is becoming increasingly important as environmental concerns and regulations require more sensitive measurement of the radioactivity levels in the workplace and the home. In measuring this activity, however, the background becomes one of the limiting factors. Anticoincidence systems utilizing both NaI(T1) and plastic scintillators have proven effective in reducing some components of the background, but radiocontaminants in the various regions of these systems have limited their effectiveness, and their cost is often prohibitive. In order to obtain a genuinely low background detector system, all components must be free of detectable radioactivity, and the cosmic ray produced contribution must be significantly reduced. Current efforts by the authors to measure the double beta decay of Germanium 76 as predicted by Grand Unified Theories have resulted in the development of a high resolution germanium diode gamma spectrometer with an exceptionally low background. This paper describes the development of this system, outlines the configuration and operation of its preamplifier, linear amplifier, analog-to-digital converter, 4096-channel analyzer, shielding consisting of lead-sandwiched plastic scintillators wrapped in cadmium foil, photomultiplier, and its pulse generator and discriminator, and then discusses how the system can be utilized to significantly reduce the background in high resolution photon spectrometers at only moderate cost

  15. Study and characterization of porous germanium for radiometric measurements

    Energy Technology Data Exchange (ETDEWEB)

    Akkari, E.; Benachour, Z.; Touayar, O.; Benbrahim, J. [Activites de Recherche, Metrologie des Rayonnements, Institut National des Sciences Appliquees et de Technologie, INSAT, Tunis (Tunisia); Aouida, S.; Bessais, B. [Laboratoire de Nanomateriaux et des Systemes de l' Energie, LaNSE, Centre de Recherche et des Technologies de l' Energie, CRTEn, Hammam-Lif (Tunisia)

    2009-07-15

    The aim of this article is to study and realize a new detector based on a porous germanium (pGe) photodiode to be used as a standard for radiometric measurement in the wavelength region between 800 nm and 1700 nm. We present the development and characterization of a porous structure realized on a single-crystal substrate of p-type germanium (Ga doped) and of crystallographic orientation (100). The obtained structure allows, on the one hand, to trap the incident radiation, and on the other hand, to minimize the fluctuations of the front-face reflection coefficient of the photodiode. The first studies thus made show that it is possible to optimize, respectively, the electrical current density and the electrochemical operation time necessary for obtaining exploitable porous structures. The obtained results show that for 50 mA/cm{sup 2} and 5 min as operational parameters, we obtain a textured aspect of the porous samples that present a pyramidal form. The reflectivity study of the front surface shows a constant value of around 38% in a spectral range between 800 nm and 1700 nm approximately. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Calibration curve for germanium spectrometers from solutions calibrated by liquid scintillation counting

    International Nuclear Information System (INIS)

    Grau, A.; Navarro, N.; Rodriguez, L.; Alvarez, A.; Salvador, S.; Diaz, C.

    1996-01-01

    The beta-gamma emitters ''60Co, ''137 Cs, ''131 I, ''210 Pb y ''129 Iare radionuclides for which the calibration by the CIEMAT/NIST method ispossible with uncertainties less than 1%. We prepared, from standardized solutions of these radionuclides, samples in vials of 20 ml. We obtained the calibration curves, efficiency as a function of energy, for two germanium detectors. (Author) 5 refs

  17. Radiation detectors laboratory

    International Nuclear Information System (INIS)

    Ramirez J, F.J.

    1996-01-01

    The National Institute for Nuclear Research has established a Radiation detector laboratory that has the possibility of providing to the consultants on the handling and applications of the nuclear radiation detectors. It has special equipment to repair the radiation detectors used in spectroscopy as the hyper pure Germanium for gamma radiation and the Lithium-silica for X-rays. There are different facilities in the laboratory that can become useful for other institutions that use radiation detectors. This laboratory was created to satisfy consultant services, training and repairing of the radiation detectors both in national and regional levels for Latin America. The laboratory has the following sections: Nuclear Electronic Instrumentation; where there are all kind of instruments for the measurement and characterization of detectors like multichannel analyzers of pulse height, personal computers, amplifiers and nuclear pulse preamplifiers, nuclear pulses generator, aleatories, computer programs for radiation spectra analysis, etc. High vacuum; there is a vacuum escape measurer, two high vacuum pumps to restore the vacuum of detectors, so the corresponding measurers and the necessary tools. Detectors cleaning; there is an anaerobic chamber for the detectors handling at inert atmosphere, a smoke extraction bell for cleaning with the detector solvents. Cryogenic; there are vessels and tools for handling liquid nitrogen which is used for cooling the detectors when they required it. (Author)

  18. Germanium content in Polish hard coals

    Directory of Open Access Journals (Sweden)

    Makowska Dorota

    2016-01-01

    Full Text Available Due to the policy of the European Union, it is necessary to search for new sources of scarce raw materials. One of these materials is germanium, listed as a critical element. This semi-metal is widely used in the electronics industry, for example in the production of semiconductors, fibre optics and solar cells. Coal and fly ash from its combustion and gasification for a long time have been considered as a potential source of many critical elements, particularly germanium. The paper presents the results of germanium content determination in the Polish hard coal. 23 coal samples of various coal ranks were analysed. The samples were collected from 15 mines of the Upper Silesian Coal Basin and from one mine of the Lublin Coal Basin. The determination of germanium content was performed with the use of Atomic Absorption Spectrometry with Electrothermal Atomization (GFAAS. The investigation showed that germanium content in the analysed samples was at least twice lower than the average content of this element in the hard coals analysed so far and was in the range of 0.08 ÷ 1.28 mg/kg. Moreover, the content of Ge in the ashes from the studied coals does not exceed 15 mg/kg, which is lower than the average value of Ge content in the coal ashes. The highest content of this element characterizes coals of the Lublin Coal Basin and young coals type 31 from the Vistula region. The results indicate a low utility of the analysed coal ashes as a source of the recovery of germanium. On the basis of the analyses, the lack of the relationship between the content of the element and the ash content in the tested coals was noted. For coals of the Upper Silesian Coal Basin, the relationship between the content of germanium in the ashes and the depth of the seam was observed.

  19. Long-wavelength germanium photodetectors by ion implantation

    International Nuclear Information System (INIS)

    Wu, I.C.; Beeman, J.W.; Luke, P.N.; Hansen, W.L.; Haller, E.E.

    1990-11-01

    Extrinsic far-infrared photoconductivity in thin high-purity germanium wafers implanted with multiple-energy boron ions has been investigated. Initial results from Fourier transform spectrometer(FTS) measurements have demonstrated that photodetectors fabricated from this material have an extended long-wavelength threshold near 192μm. Due to the high-purity substrate, the ability to block the hopping conduction in the implanted IR-active layer yields dark currents of less than 100 electrons/sec at temperatures below 1.3 K under an operating bias of up to 70 mV. Optimum peak responsivity and noise equivalent power (NEP) for these sensitive detectors are 0.9 A/W and 5 x 10 -16 W/Hz 1/2 at 99 μm, respectively. The dependence of the performance of devices on the residual donor concentration in the implanted layer will be discussed. 12 refs., 4 figs

  20. Method of beryllium implantation in germanium substrate

    International Nuclear Information System (INIS)

    Kagawa, S.; Baba, Y.; Kaneda, T.; Shirai, T.

    1983-01-01

    A semiconductor device is disclosed, as well as a method for manufacturing it in which ions of beryllium are implanted into a germanium substrate to form a layer containing p-type impurity material. There after the substrate is heated at a temperature in the range of 400 0 C. to 700 0 C. to diffuse the beryllium ions into the substrate so that the concentration of beryllium at the surface of the impurity layer is in the order of 10 17 cm- 3 or more. In one embodiment, a p-type channel stopper is formed locally in a p-type germanium substrate and an n-type active layer is formed in a region surrounded by, and isolated from, the channel stopper region. In another embodiment, a relatively shallow p-type active layer is formed at one part of an n-type germanium substrate and p-type guard ring regions are formed surrounding, and partly overlapping said p-type active layer. In a further embodiment, a p-type island region is formed at one part of an n-type germanium substrate, and an n-type region is formed within said p-type region. In these embodiments, the p-type channel stopper region, p-type guard ring regions and the p-type island region are all formed by implanting ions of beryllium into the germanium substrate

  1. Experimental Search for Solar Axions via Coherent Primakoff Conversion in a Germanium Spectrometer

    CERN Document Server

    Avignone, F T; Brodzinski, R; Collar, J I; Creswick, R J; Di Gregorio, D E; Farach, H A; Gattone, A O; Guérard, C K; Hasenbalg, F; Huck, H; Miley, H S; Morales, A; Morales, J; Nussinov, S; De Solorzano, A O; Reeves, J H; Villar, J; Zioutas, Konstantin

    1998-01-01

    Results are reported of an experimental search for the unique, rapidly varying temporal pattern of solar axions coherently converting into photons via the Primakoff effect in a single crystal germanium detector. This conversion is predicted when axions are incident at a Bragg angle with a crystalline plane. The analysis of approximately 1.94 kg.yr of data from the 1 kg DEMOS detector in Sierra Grande, Argentina, yields a new laboratory bound on axion-photon coupling of $g_{a\\gamma \\gamma} < 2.7\\cdot 10^{-9}$ GeV$^{-1}$, independent of axion mass up to ~ 1 keV.

  2. Advanced radiation detector development mercuric iodide, silicon with internal gain, hybrid scintillator/semiconductor detectors. Comprehensive summary report, 1976-1985

    International Nuclear Information System (INIS)

    Huth, G.C.; Dabrowski, A.J.

    1985-01-01

    Accomplishments are reported in the development of a compound semi-insulator mercuric iodide (HgI 2 ) for nuclear radiation detection and spectroscopy, early lung cancer detection and localization in the uranium miner/worker population, computer digital image processing and image reconstruction research, and a concept for multiple, filtered x-ray computed tomography scanning to reveal chemical compositional information. Another area of interest is the study of new advances in the area of silicon detectors with internal gain (''avalanche'')

  3. Neutron-transmutation-doped germanium bolometers

    International Nuclear Information System (INIS)

    Palaio, N.P.; Rodder, M.; Haller, E.E.; Kreysa, E.

    1983-02-01

    Six slices of ultra-pure germanium were irradiated with thermal neutron fluences between 7.5 x 10 16 and 1.88 x 10 18 cm - 2 . After thermal annealing the resistivity was measured down to low temperatures ( 0 exp(δ/T) in the hopping conduction regime. Also, several junction FETs were tested for noise performance at room temperature and in an insulating housing in a 4.2K cryostat. These FETs will be used as first stage amplifiers for neutron-transmutation-doped germanium bolometers

  4. Neutron-transmutation-doped germanium bolometers

    Science.gov (United States)

    Palaio, N. P.; Rodder, M.; Haller, E. E.; Kreysa, E.

    1983-01-01

    Six slices of ultra-pure germanium were irradiated with thermal neutron fluences between 7.5 x 10 to the 16th and 1.88 x 10 to the 18th per sq cm. After thermal annealing the resistivity was measured down to low temperatures (less than 4.2 K) and found to follow the relationship rho = rho sub 0 exp(Delta/T) in the hopping conduction regime. Also, several junction FETs were tested for noise performance at room temperature and in an insulating housing in a 4.2 K cryostat. These FETs will be used as first stage amplifiers for neutron-transmutation-doped germanium bolometers.

  5. Germanium-overcoated niobium Dayem bridges

    International Nuclear Information System (INIS)

    Holdeman, L.B.; Peters, P.N.

    1976-01-01

    Overcoating constriction microbridges with semiconducting germanium provides additional thermal conductivity at liquid-helium temperatures to reduce the effects of self-heating in these Josephson junctions. Microwave-induced steps were observed in the I-V characteristics of an overcoated Dayem bridge fabricated in a 15-nm-thick niobium film; at 4.2 K (T/sub c/-T=2.6 K), at least 20 steps could be counted. No steps were observed in the I-V characteristics of the bridge prior to overcoating. In addition, the germanium overcoat can protect against electrical disturbances at room temperature

  6. P.I.X.S.C.A.N.: a micro-CT scanner for small animal based on hybrid pixel detectors

    International Nuclear Information System (INIS)

    Khoury, R.

    2008-03-01

    Since more than a dozen years, efforts were led in the field of X-ray tomography for small animals, principally for the improvement of spatial resolution and the diminution of the absorbed dose. The C.P.P.M. developed the micro-CT P.I.X.S.C.A.N. based on the hybrid pixel detector X.P.A.D.2. In this context, my thesis work consists in studying the demonstrator P.I.X.S.C.A.N./X.P.A.D.2 and the contribution of the hybrid pixels in the imaging of small animals. A fast analytical simulation, FastSimu, was developed. An extrapolation of the performance of the demonstrator P.I.X.S.C.A.N, as well as the validation of the results obtained with the measured data, were led by means of the analytical simulator FastSimu. The demonstrator P.I.X.S.C.A.N./X.P.A.D.2 allowed to obtain reconstructed images with a rather good quality for a relatively weak absorbed dose. Its spatial resolution is degraded by the high number of defective pixels of the detector X.P.A.D.2. Beyond this study, a new version of the demonstrator P.I.X.S.C.A.N./X.P.A.D.2 is under construction. This latter, characterized by two and a half times smaller pixels and about no defective pixels will bring a considerable improvement on spatial resolution. (author)

  7. P.I.X.S.C.A.N.: a micro-CT scanner for small animal based on hybrid pixel detectors; PIXSCAN: micro-tomodensitrometre a pixels hybrides pour le petit animal

    Energy Technology Data Exchange (ETDEWEB)

    Khoury, R

    2008-03-15

    Since more than a dozen years, efforts were led in the field of X-ray tomography for small animals, principally for the improvement of spatial resolution and the diminution of the absorbed dose. The C.P.P.M. developed the micro-CT P.I.X.S.C.A.N. based on the hybrid pixel detector X.P.A.D.2. In this context, my thesis work consists in studying the demonstrator P.I.X.S.C.A.N./X.P.A.D.2 and the contribution of the hybrid pixels in the imaging of small animals. A fast analytical simulation, FastSimu, was developed. An extrapolation of the performance of the demonstrator P.I.X.S.C.A.N, as well as the validation of the results obtained with the measured data, were led by means of the analytical simulator FastSimu. The demonstrator P.I.X.S.C.A.N./X.P.A.D.2 allowed to obtain reconstructed images with a rather good quality for a relatively weak absorbed dose. Its spatial resolution is degraded by the high number of defective pixels of the detector X.P.A.D.2. Beyond this study, a new version of the demonstrator P.I.X.S.C.A.N./X.P.A.D.2 is under construction. This latter, characterized by two and a half times smaller pixels and about no defective pixels will bring a considerable improvement on spatial resolution. (author)

  8. The establishment of bed type germanium-based whole body counters

    International Nuclear Information System (INIS)

    Chen, M.C.; Sun, C.L.; Yeh, W.W.

    1996-01-01

    A coaxial germanium detector was installed in a shadow-shield counter for the in-vivo measurement of γ emitters in the body. It is divided into two subparts, automatic liquid nitrogen transfer system and the Ge-based counting system. The automatic liquid nitrogen transfer system and a complete gamma spectroscopy software package were manufactured by EG and G ORTEC company. Some experiments were finished to get the optimum three setting parameters for how to operate the auto liquid nitrogen transfer system in good conditions. The filling interval should be setting at eight hours, the filling time should be setting at ten minutes, and the pressure of dewar should operate in a range from 14 to 26 PSI. The RMC-II phantom that is designed by Canberra company is used as standard man for all kinds of calibrations. The detector has resolutions that are less than 2.5 keV with an average of 1.87 keV for the 60 Co 1.33-MeV γ-ray peak. The efficiency value of thyroid geometry for four different organs is highest in the phantom. The resolution of the Germanium detector for measuring radioactivity in the body that is better than the sodium iodide detector is used to measure the internal depositions of radionuclide mixtures. So, the advantage of the germanium counter can just compensate the disadvantage of the NaI(TI) detector. The qualitative and quantitative analysis for whole body counting can keep in the best conditions if both whole body counters are operated at the same time for routine measurement purpose in the laboratory

  9. Boron doping compensation of hydrogenated amorphous and polymorphous germanium thin films for infrared detection applications

    International Nuclear Information System (INIS)

    Moreno, M.; Delgadillo, N.; Torres, A.; Ambrosio, R.; Rosales, P.; Kosarev, A.; Reyes-Betanzo, C.; Hidalga-Wade, J. de la; Zuniga, C.; Calleja, W.

    2013-01-01

    In this work we have studied boron doping of hydrogenated amorphous germanium a-Ge:H and polymorphous germanium (pm-Ge:H) in low regimes, in order to compensate the material from n-type (due to oxygen contamination that commonly occurs during plasma deposition) to intrinsic, and in this manner improve the properties that are important for infrared (IR) detection, as activation energy (E a ) and temperature coefficient of resistance (TCR). Electrical, structural and optical characterization was performed on the films produced. Measurements of the temperature dependence of conductivity, room temperature conductivity (σ RT ), E a and current–voltage characteristics under IR radiation were performed in the compensated a-Ge:H and pm-Ge:H films. Our results demonstrate that, effectively, the values of E a , TCR and IR detection are improved on the a-Ge:H/pm-Ge:H films, using boron doping in low regimes, which results of interest for infrared detectors. - Highlights: • We reported boron doping compensation of amorphous and polymorphous germanium. • The films were deposited by plasma enhanced chemical vapor deposition. • The aim is to use the films as thermo-sensing elements in un-cooled microbolometers. • Those films have advantages over boron doped a-Si:H used in commercial detectors

  10. Boron doping compensation of hydrogenated amorphous and polymorphous germanium thin films for infrared detection applications

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, M., E-mail: mmoreno@inaoep.mx [National Institute of Astrophysics, Optics and Electronics, INAOE, P.O. Box 51 and 216, Puebla, Z. P. 72840 Puebla (Mexico); Delgadillo, N. [Universidad Autónoma de Tlaxcala, Av. Universidad No. 1, Z. P. 90006 Tlaxcala (Mexico); Torres, A. [National Institute of Astrophysics, Optics and Electronics, INAOE, P.O. Box 51 and 216, Puebla, Z. P. 72840 Puebla (Mexico); Ambrosio, R. [Technology and Engineering Institute, Ciudad Juarez University UACJ, Av. Del Charro 450N, Z. P. 32310 Chihuahua (Mexico); Rosales, P.; Kosarev, A.; Reyes-Betanzo, C.; Hidalga-Wade, J. de la; Zuniga, C.; Calleja, W. [National Institute of Astrophysics, Optics and Electronics, INAOE, P.O. Box 51 and 216, Puebla, Z. P. 72840 Puebla (Mexico)

    2013-12-02

    In this work we have studied boron doping of hydrogenated amorphous germanium a-Ge:H and polymorphous germanium (pm-Ge:H) in low regimes, in order to compensate the material from n-type (due to oxygen contamination that commonly occurs during plasma deposition) to intrinsic, and in this manner improve the properties that are important for infrared (IR) detection, as activation energy (E{sub a}) and temperature coefficient of resistance (TCR). Electrical, structural and optical characterization was performed on the films produced. Measurements of the temperature dependence of conductivity, room temperature conductivity (σ{sub RT}), E{sub a} and current–voltage characteristics under IR radiation were performed in the compensated a-Ge:H and pm-Ge:H films. Our results demonstrate that, effectively, the values of E{sub a}, TCR and IR detection are improved on the a-Ge:H/pm-Ge:H films, using boron doping in low regimes, which results of interest for infrared detectors. - Highlights: • We reported boron doping compensation of amorphous and polymorphous germanium. • The films were deposited by plasma enhanced chemical vapor deposition. • The aim is to use the films as thermo-sensing elements in un-cooled microbolometers. • Those films have advantages over boron doped a-Si:H used in commercial detectors.

  11. Electron, hole and exciton self-trapping in germanium doped silica glass from DFT calculations with self-interaction correction

    International Nuclear Information System (INIS)

    Du Jincheng; Rene Corrales, L.; Tsemekhman, Kiril; Bylaska, Eric J.

    2007-01-01

    Density functional theory (DFT) calculations were employed to understand the refractive index change in germanium doped silica glasses for the trapped states of electronic excitations induced by UV irradiation. Local structure relaxation and excess electron density distribution were calculated upon self-trapping of an excess electron, hole, and exciton in germanium doped silica glass. The results show that both the trapped exciton and excess electron are highly localized on germanium ion and, to some extent, on its oxygen neighbors. Exciton self-trapping is found to lead to the formation of a Ge E' center and a non-bridging hole center. Electron trapping changes the GeO 4 tetrahedron structure into trigonal bi-pyramid with the majority of the excess electron density located along the equatorial line. The self-trapped hole is localized on bridging oxygen ions that are not coordinated to germanium atoms that lead to elongation of the Si-O bonds and change of the Si-O-Si bond angles. We carried out a comparative study of standard DFT versus DFT with a hybrid PBE0 exchange and correlation functional. The results show that the two methods give qualitatively similar relaxed structure and charge distribution for electron and exciton trapping in germanium doped silica glass; however, only the PBE0 functional produces the self-trapped hole

  12. GRAN SASSO: Enriched germanium in action

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1991-12-15

    Two large crystals of carefully enriched germanium, one weighing 1 kilogram and the other 2.9 kilograms, and worth many millions of dollars, are being carefully monitored in the Italian Gran Sasso Laboratory in the continuing search for neutrinoless double beta decay.

  13. GRAN SASSO: Enriched germanium in action

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Two large crystals of carefully enriched germanium, one weighing 1 kilogram and the other 2.9 kilograms, and worth many millions of dollars, are being carefully monitored in the Italian Gran Sasso Laboratory in the continuing search for neutrinoless double beta decay

  14. Filtering microphonics in dark matter germanium experiments

    International Nuclear Information System (INIS)

    Morales, J.; Garcia, E.; Ortiz de Solorzano, A.; Morales, A.; Nunz-Lagos, R.; Puimedon, J.; Saenz, C.; Villar, J.A.

    1992-01-01

    A technique for reducing the microphonic noise in a germanium spectrometer used in dark matter particles searches is described. Filtered energy spectra, corresponding to 48.5 kg day of data in a running experiment in the Canfranc tunnel are presented. Improvements of this filtering procedure with respect to the method of rejecting those events not distributed evenly in time are also discussed. (orig.)

  15. Neutron Transmission of Germanium Poly- and Monocrystals

    International Nuclear Information System (INIS)

    Habib, N.

    2009-01-01

    The measured total neutron cross-sections of germanium poly- and mono-crystals were analyzed using an additive formula. The formula takes into account the germanium crystalline structure and its physical parameters. Computer programs have developed in order to provide the required analyses. The calculated values of the total cross-section of polycrystalline germanium in the neutron wavelength range from 0.001 up to 0.7 nm were fitted to the measured ones at ETRR-1. From the fitting the main constants of the additive formula were determined. The experimental data measured at ETRR-1 of the total cross-section of high quality Ge single crystal at 4400 K, room, and liquid nitrogen temperatures, in the wavelength range between 0.028 nm and 0.64 nm, were also compared with the calculated values using the formula having the same constants. An overall agreement is noticed between the formula fits and experimental data. A feasibility study is done for the use of germanium in poly-crystalline form, as cold neutron filter, and in mono-crystalline one as an efficient filter for thermal neutrons. The filtering efficiency of Ge single crystal is detailed in terms of its isotopic abundance, crystal thickness, mosaic spread, and temperature. It can be concluded that the 7.5 cm thick 76 Ge single crystal (0.10 FWHM mosaic spread) cooled at liquid nitrogen temperature is an efficient thermal neutron filter.

  16. Mesostructured germanium with cubic pore symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Armatas, G S; Kanatzidis, M G [Michigan State Univ., Michigan (United States), Dept. of Chemistry

    2006-11-15

    Regular mesoporous oxide materials have been widely studied and have a range of potential applications, such as catalysis, absorption and separation. They are not generally considered for their optical and electronic properties. Elemental semiconductors with nanopores running through them represent a different form of framework material with physical characteristics contrasting with those of the more conventional bulk, thin film and nanocrystalline forms. Here we describe cubic meso structured germanium, MSU-Ge-l, with gyroidal channels containing surfactant molecules, separated by amorphous walls that lie on the gyroid (G) minimal surface as in the mesoporous silica MCM-48. Although Ge is a high-meltin covalent semiconductor that is difficult to prepare from solution polymerization, we succeeded in assembling a continuous Ge network using a suitable precursor for Ge{sup 4-} atoms. Our results indicate that elemental semiconductors from group 14 of the periodic table can be made to adopt meso structured forms such as MSU-Ge-1, which features two three-dimensional labyrinthine tunnels obeying la3d space group symmetry and separated by a continuous germanium minimal surface that is otherwise amorphous. A consequence of this new structure for germanium, which has walls only one nanometre thick, is a wider electronic energy bandgap (1.4 eV versus 0.66 eV) than has crystalline or amorphous Ge. Controlled oxidation of MSU-Ge-1 creates a range of germanium suboxides with continuously varying Ge:O ratio and a smoothly increasing energy gap. (author)

  17. Characterization of nanocrystalline silicon germanium film and ...

    African Journals Online (AJOL)

    The nanocrystalline silicon-germanium films (Si/Ge) and Si/Ge nanotubes have low band gaps and high carrier mobility, thus offering appealing potential for absorbing gas molecules. Interaction between hydrogen molecules and bare as well as functionalized Si/Ge nanofilm and nanotube was investigated using Monte ...

  18. Imaging of gamma rays with the WINKLER high-resolution germanium spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, T.R.; Hamilton, T.W.; Hawley, J.D.; Kilner, J.R.; Murphy, M.J.; Nakano, G.H. (Luckheed Palo Alto Research Lab., Palo Alto, CA (US))

    1990-06-01

    The WINKLER spectrometer is a matrix of nine high-purity {ital n}-type germanium detectors developed for astrophysical observations and terrestrial radiation monitoring. The spectrometer has been fitted with a set of modulation collimator grids designed for imaging hard x-ray and gamma-ray sources by the Mertz, Nakano, and Kilner method. This technique employs a pair of gridded collimators in front of each detector with the number of grid bars varying from one to {ital N}, where {ital N} is the number of detectors. When the collimator pairs are rotated through a full 360-degree angular range, the detector signals provide the information for a two-dimensional band-limited Fourier reconstruction of order {ital N}. Tests of the spectrometer with single and multiple point sources as well as continuous source distributions are reported.

  19. Deformation potentials for band-to-band tunneling in silicon and germanium from first principles

    Science.gov (United States)

    Vandenberghe, William G.; Fischetti, Massimo V.

    2015-01-01

    The deformation potentials for phonon-assisted band-to-band tunneling (BTBT) in silicon and germanium are calculated using a plane-wave density functional theory code. Using hybrid functionals, we obtain: DTA = 4.1 × 108 eV/cm, DTO = 1.2 × 109 eV/cm, and DLO = 2.2 × 109 eV/cm for BTBT in silicon and DTA = 7.8 × 108 eV/cm and DLO = 1.3 × 109 eV/cm for BTBT in germanium. These values agree with experimentally measured values and we explain why in diodes, the TA/TO phonon-assisted BTBT dominates over LO phonon-assisted BTBT despite the larger deformation potential for the latter. We also explain why LO phonon-assisted BTBT can nevertheless dominate in many practical applications.

  20. Development of a Schottky CdTe Medipix3RX hybrid photon counting detector with spatial and energy resolving capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Gimenez, E.N., E-mail: Eva.Gimenez@diamond.ac.uk [Diamond Light Source, Harwell Campus, Oxforshire OX11 0DE (United Kingdom); Astromskas, V. [University of Surrey (United Kingdom); Horswell, I.; Omar, D.; Spiers, J.; Tartoni, N. [Diamond Light Source, Harwell Campus, Oxforshire OX11 0DE (United Kingdom)

    2016-07-11

    A multichip CdTe-Medipix3RX detector system was developed in order to bring the advantages of photon-counting detectors to applications in the hard X-ray range of energies. The detector head consisted of 2×2 Medipix3RX ASICs bump-bonded to a 28 mm×28 mm e{sup −} collection Schottky contact CdTe sensor. Schottky CdTe sensors undergo performance degrading polarization which increases with temperature, flux and the longer the HV is applied. Keeping the temperature stable and periodically refreshing the high voltage bias supply was used to minimize the polarization and achieve a stable and reproducible detector response. This leads to good quality images and successful results on the energy resolving capabilities of the system. - Highlights: • A high atomic number (CdTe sensor based) photon-counting detector was developed. • Polarization effects affected the image were minimized by regularly refreshing the bias voltage and stabilizing the temperature. • Good spatial resolution and image quality was achieved following this procedure.

  1. The Development of a Hybrid-Type Radiation Detector with SiC for a Reactor Robot

    International Nuclear Information System (INIS)

    Lee, Nam Ho; Cho, Jai Wan; Kim, Seung Ho

    2005-01-01

    For a robot working in a harsh environment such as a nuclear reactor environment or a space environment, requirements of on-board radiation detectors are not the same as those for environments around human. SiC devices with the wide band-gap are less dependent on temperature than Si counterparts and the can be the better candidate for the high radiation environment. With this background, radiation performance of a commercial SiC detector in a Co-60 gamma-ray environment has been evaluated. In addition to the SiC detector, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) detector has been incorporated as a backup. With this MOSFET sensor the dosimeter can keep its radiation exposure history even with loss of power. It is not only a redundant feature but also a diverse feature. The dosimetry module can be attached to mobile robot for high radiation environment was developed. This module has both SiC diode and pMOSFET mentioned above. The monitoring program which receives the radiation information from them and gives out the alarm signal when the difference of the two values from them is over the preset level was constructed. Because both the SiC pulse-type detector and the MOSFET dosimeter are small and light weight, they can be easily accommodated on a small printcircuit board for a tight space on a robot arm or for a small spacecraft

  2. Comparison of experimental and theoretical efficiency of HPGe X-ray detector

    International Nuclear Information System (INIS)

    Mohanty, B.P.; Balouria, P.; Garg, M.L.; Nandi, T.K.; Mittal, V.K.; Govil, I.M.

    2008-01-01

    The low energy high purity germanium (HPGe) detectors are being increasingly used for the quantitative estimation of elements using X-ray spectrometric techniques. The softwares used for quantitative estimation normally evaluate model based efficiency of detector using manufacturer supplied detector physical parameters. The present work shows that the manufacturer supplied detector parameters for low energy HPGe detectors need to be verified by comparing model based efficiency with the experimental ones. This is particularly crucial for detectors with ion implanted P type contacts

  3. Active volume studies with depleted and enriched BEGe detectors

    Energy Technology Data Exchange (ETDEWEB)

    Sturm, Katharina von [Eberhard Karls Universitaet Tuebingen (Germany); Universita degli Studi di Padova, Padua (Italy); Collaboration: GERDA-Collaboration

    2013-07-01

    The Gerda experiment is currently taking data for the search of the 0νββ decay in {sup 76}Ge. In 2013, 30 newly manufactured Broad Energy Germanium (BEGe) diodes will be deployed which will double the active mass within Gerda. These detectors were fabricated from high-purity germanium enriched in {sup 76}Ge and tested in the HADES underground laboratory, owned by SCK.CEN, in Mol, Belgium. As the BEGes are source and detector at the same time, one crucial parameter is their active volume which directly enters into the evaluation of the half-life. This talk illustrates the dead layer and active volume determination of prototype detectors from depleted germanium as well as the newly produced detectors from enriched material, using gamma spectroscopy methods and comparing experimental results to Monte-Carlo simulations. Recent measurements and their results are presented, and systematic effects are discussed.

  4. hybrid\\scriptsize{{MANTIS}}: a CPU-GPU Monte Carlo method for modeling indirect x-ray detectors with columnar scintillators

    Science.gov (United States)

    Sharma, Diksha; Badal, Andreu; Badano, Aldo

    2012-04-01

    The computational modeling of medical imaging systems often requires obtaining a large number of simulated images with low statistical uncertainty which translates into prohibitive computing times. We describe a novel hybrid approach for Monte Carlo simulations that maximizes utilization of CPUs and GPUs in modern workstations. We apply the method to the modeling of indirect x-ray detectors using a new and improved version of the code \\scriptsize{{MANTIS}}, an open source software tool used for the Monte Carlo simulations of indirect x-ray imagers. We first describe a GPU implementation of the physics and geometry models in fast\\scriptsize{{DETECT}}2 (the optical transport model) and a serial CPU version of the same code. We discuss its new features like on-the-fly column geometry and columnar crosstalk in relation to the \\scriptsize{{MANTIS}} code, and point out areas where our model provides more flexibility for the modeling of realistic columnar structures in large area detectors. Second, we modify \\scriptsize{{PENELOPE}} (the open source software package that handles the x-ray and electron transport in \\scriptsize{{MANTIS}}) to allow direct output of location and energy deposited during x-ray and electron interactions occurring within the scintillator. This information is then handled by optical transport routines in fast\\scriptsize{{DETECT}}2. A load balancer dynamically allocates optical transport showers to the GPU and CPU computing cores. Our hybrid\\scriptsize{{MANTIS}} approach achieves a significant speed-up factor of 627 when compared to \\scriptsize{{MANTIS}} and of 35 when compared to the same code running only in a CPU instead of a GPU. Using hybrid\\scriptsize{{MANTIS}}, we successfully hide hours of optical transport time by running it in parallel with the x-ray and electron transport, thus shifting the computational bottleneck from optical to x-ray transport. The new code requires much less memory than \\scriptsize{{MANTIS}} and, as a result

  5. Experimental MRI-SPECT insert system with Hybrid Semiconductor detectors Timepix for MR animal scanner Bruker 47/20

    Czech Academy of Sciences Publication Activity Database

    Zajíček, J.; Burian, M.; Soukup, P.; Novák, Vladimír; Macko, M.; Jakůbek, J.

    2017-01-01

    Roč. 12, January (2017), č. článku P01015. ISSN 1748-0221 Institutional support: RVO:68378297 Keywords : Gamma camera * SPECT * PET PET /CT * coronary CT angiography (CTA) * Gamma detectors (scintillators, CZT, HPG, HgI etc) * multi-modality systems * pixelated detectors and associated VLSI electronics Subject RIV: JB - Sensors, Measurment, Regulation OBOR OECD: Electrical and electronic engineering Impact factor: 1.220, year: 2016 http://iopscience.iop.org/article/10.1088/1748-0221/12/01/P01015

  6. Comparison of the NaI-CsI phoswich and a hyperpure germanium array for in vivo detection of the actinides

    Energy Technology Data Exchange (ETDEWEB)

    Berger, C D; Goans, R E [Oak Ridge National Lab., TN (USA)

    1981-04-01

    An array of hyperpure germanium detectors has recently been employed at ORNL for the identification and quantification of internally deposited actinides. Its advantages over the phoswich detector - the current state-of-the-art for detection of the actinides - were found to be improved background reduction and superior energy resolution. The germanium system and the currently operating phoswich system are discussed and compared. The improvement in performance of the germanium system over the phoswich system (a factor of 2.5 for /sup 239/Pu and 15.3 for /sup 241/Am) appears to justify the financial investment, particularly when /sup 241/Am is used as an indirect means of detection and measurement of /sup 239/Pu.

  7. gamma-ray tracking in germanium the backtracking method

    CERN Document Server

    Marel, J V D

    2002-01-01

    In the framework of a European TMR network project the concept for a gamma-ray tracking array is being developed for nuclear physics spectroscopy in the energy range of approx 10 keV up to several MeV. The tracking array will consist of a large number of position-sensitive germanium detectors in a spherical geometry around a target. Due to the high segmentation, a Compton scattered gamma-ray will deposit energy in several different segments. A method has been developed to reconstruct the tracks of multiple coincident gamma-rays and to find their initial energies. By starting from the final point the track can be reconstructed backwards to the origin with the help of the photoelectric and Compton cross-sections and the Compton scatter formula. Every reconstructed track is given a figure of merit, thus allowing suppression of wrongly reconstructed tracks and gamma-rays that have scattered out of the detector system. This so-called backtracking method has been tested on simulated events in a shell-like geometry ...

  8. The ACCUSCAN-II vertical scanning germanium whole body counter

    International Nuclear Information System (INIS)

    Bronson, F.L.

    1987-01-01

    The ACCUSCAN-II is manufactured by Canberra Industries, and represents a new generation of WBC systems. One or two Germanium detectors are used for precise nuclide identification. The detectors scan the total body and can accurately quantify radioactive material anywhere in the body. The shield is a full 4'' thick steel or 2'' lead and weighs about 9000 lbs. The subject can be counted standing for full body scans, or seated for longer counting times of limited portions of the body. Optional electronics also generate a count rate vs. body position profile, as an aid to interpretation of the dose implications of the count. Typical LLD's are 5 - 10 nCi for a 5 minute total body count and 0.5 - 0.7 nCi for a 5 minute long screening count. The system is available in several flavors. The manual version is an inexpensive system intended for universities, hospitals and small industrial facilities. The automatic system includes a MicroVAX-II computer and runs ABACOS0-II Body Burden Software, and is ideal for facilities with large numbers of people to count and where automated analysis of the data is desirable

  9. Simulation results for PLATO: a prototype hybrid X-ray photon counting detector with a low energy threshold for fusion plasma diagnostics

    International Nuclear Information System (INIS)

    Habib, A.; Menouni, M.; Pangaud, P.; Morel, C.; Fenzi, C.; Colledani, G.; Moureau, G.; Escarguel, A.

    2017-01-01

    PLATO is a prototype hybrid X-ray photon counting detector that has been designed to meet the specifications for plasma diagnostics for the WEST tokamak platform (Tungsten (W) Environment in Steady-state Tokamak) in southern France, with potential perspectives for ITER. PLATO represents a customized solution that fulfills high sensitivity, low dispersion and high photon counting rate. The PLATO prototype matrix is composed of 16 × 18 pixels with a 70 μm pixel pitch. New techniques have been used in analog sensitive blocks to minimize noise coupling through supply rails and substrate, and to suppress threshold dispersion across the matrix. The PLATO ASIC is designed in CMOS 0.13 μm technology and was submitted for a fabrication run in June 2016. The chip is designed to be bump-bonded to a silicon sensor. This paper presents pixel architecture as well as simulation results while highlighting novel solutions.

  10. The processing of enriched germanium for the MAJORANA DEMONSTRATOR and R&D for a next generation double-beta decay experiment

    Science.gov (United States)

    Abgrall, N.; Arnquist, I. J.; Avignone, F. T., III; Barabash, A. S.; Bertrand, F. E.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Caja, J.; Caja, M.; Caldwell, T. S.; Christofferson, C. D.; Chu, P.-H.; Cuesta, C.; Detwiler, J. A.; Dunagan, C.; Dunstan, D. T.; Efremenko, Yu.; Ejiri, H.; Elliott, S. R.; Gilliss, T.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Haufe, C. R. S.; Henning, R.; Hoppe, E. W.; Jasinski, B. R.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; Lopez, A. M.; MacMullin, J.; Martin, R. D.; Massarczyk, R.; Meijer, S. J.; Mertens, S.; Meyer, J. H.; Myslik, J.; O'Shaughnessy, C.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Reine, A. L.; Reising, J. A.; Rielage, K.; Robertson, R. G. H.; Shanks, B.; Shirchenko, M.; Suriano, A. M.; Tedeschi, D.; Toth, L. M.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.; Zhitnikov, I.; Zhu, B. X.

    2018-01-01

    The MAJORANA DEMONSTRATOR is an array of point-contact Ge detectors fabricated from Ge isotopically enriched to 88% in 76 Ge to search for neutrinoless double beta decay. The processing of Ge for germanium detectors is a well-known technology. However, because of the high cost of Ge enriched in 76 Ge special procedures were required to maximize the yield of detector mass and to minimize exposure to cosmic rays. These procedures include careful accounting for the material; shielding it to reduce cosmogenic generation of radioactive isotopes; and development of special reprocessing techniques for contaminated solid germanium, shavings, grindings, acid etchant and cutting fluids from detector fabrication. Processing procedures were developed that resulted in a total yield in detector mass of 70%. However, none of the acid-etch solution and only 50% of the cutting fluids from detector fabrication were reprocessed. Had they been processed, the projections for the recovery yield would be between 80% and 85%. Maximizing yield is critical to justify a possible future ton-scale experiment. A process for recovery of germanium from the acid-etch solution was developed with yield of about 90%. All material was shielded or stored underground whenever possible to minimize the formation of 68Ge by cosmic rays, which contributes background in the double-beta decay region of interest and cannot be removed by zone refinement and crystal growth. Formation of 68Ge was reduced by a significant factor over that in natural abundance detectors not protected from cosmic rays.

  11. Subpixel mapping and test beam studies with a HV2FEI4v2 CMOS-Sensor-Hybrid Module for the ATLAS inner detector upgrade

    Science.gov (United States)

    Bisanz, T.; Große-Knetter, J.; Quadt, A.; Rieger, J.; Weingarten, J.

    2017-08-01

    The upgrade to the High Luminosity Large Hadron Collider will increase the instantaneous luminosity by more than a factor of 5, thus creating significant challenges to the tracking systems of all experiments. Recent advancement of active pixel detectors designed in CMOS processes provide attractive alternatives to the well-established hybrid design using passive sensors since they allow for smaller pixel sizes and cost effective production. This article presents studies of a high-voltage CMOS active pixel sensor designed for the ATLAS tracker upgrade. The sensor is glued to the read-out chip of the Insertable B-Layer, forming a capacitively coupled pixel detector. The pixel pitch of the device under test is 33× 125 μm2, while the pixels of the read-out chip have a pitch of 50× 250 μm2. Three pixels of the CMOS device are connected to one read-out pixel, the information of which of these subpixels is hit is encoded in the amplitude of the output signal (subpixel encoding). Test beam measurements are presented that demonstrate the usability of this subpixel encoding scheme.

  12. Technology CAD for germanium CMOS circuit

    Energy Technology Data Exchange (ETDEWEB)

    Saha, A.R. [Department of Electronics and ECE, IIT Kharagpur, Kharagpur-721302 (India)]. E-mail: ars.iitkgp@gmail.com; Maiti, C.K. [Department of Electronics and ECE, IIT Kharagpur, Kharagpur-721302 (India)

    2006-12-15

    Process simulation for germanium MOSFETs (Ge-MOSFETs) has been performed in 2D SILVACO virtual wafer fabrication (VWF) suite towards the technology CAD for Ge-CMOS process development. Material parameters and mobility models for Germanium were incorporated in simulation via C-interpreter function. We also report on the device design issues along with the DC and RF characterization of the bulk Ge-MOSFETs, AC parameter extraction and circuit simulation of Ge-CMOS. Simulation results are compared with bulk-Si devices. Simulations predict a cut-off frequency, f {sub T} of about 175 GHz for Ge-MOSFETs compared to 70 GHz for a similar gate-length Si MOSFET. For a single stage Ge-CMOS inverter circuit, a GATE delay of 0.6 ns is predicted.

  13. Technology CAD for germanium CMOS circuit

    International Nuclear Information System (INIS)

    Saha, A.R.; Maiti, C.K.

    2006-01-01

    Process simulation for germanium MOSFETs (Ge-MOSFETs) has been performed in 2D SILVACO virtual wafer fabrication (VWF) suite towards the technology CAD for Ge-CMOS process development. Material parameters and mobility models for Germanium were incorporated in simulation via C-interpreter function. We also report on the device design issues along with the DC and RF characterization of the bulk Ge-MOSFETs, AC parameter extraction and circuit simulation of Ge-CMOS. Simulation results are compared with bulk-Si devices. Simulations predict a cut-off frequency, f T of about 175 GHz for Ge-MOSFETs compared to 70 GHz for a similar gate-length Si MOSFET. For a single stage Ge-CMOS inverter circuit, a GATE delay of 0.6 ns is predicted

  14. Germanium films by polymer-assisted deposition

    Science.gov (United States)

    Jia, Quanxi; Burrell, Anthony K.; Bauer, Eve; Ronning, Filip; McCleskey, Thomas Mark; Zou, Guifu

    2013-01-15

    Highly ordered Ge films are prepared directly on single crystal Si substrates by applying an aqueous coating solution having Ge-bound polymer onto the substrate and then heating in a hydrogen-containing atmosphere. A coating solution was prepared by mixing water, a germanium compound, ethylenediaminetetraacetic acid, and polyethyleneimine to form a first aqueous solution and then subjecting the first aqueous solution to ultrafiltration.

  15. Vacancy-indium clusters in implanted germanium

    KAUST Repository

    Chroneos, Alexander I.

    2010-04-01

    Secondary ion mass spectroscopy measurements of heavily indium doped germanium samples revealed that a significant proportion of the indium dose is immobile. Using electronic structure calculations we address the possibility of indium clustering with point defects by predicting the stability of indium-vacancy clusters, InnVm. We find that the formation of large clusters is energetically favorable, which can explain the immobility of the indium ions. © 2010 Elsevier B.V. All rights reserved.

  16. Vacancy-indium clusters in implanted germanium

    KAUST Repository

    Chroneos, Alexander I.; Kube, R.; Bracht, Hartmut A.; Grimes, Robin W.; Schwingenschlö gl, Udo

    2010-01-01

    Secondary ion mass spectroscopy measurements of heavily indium doped germanium samples revealed that a significant proportion of the indium dose is immobile. Using electronic structure calculations we address the possibility of indium clustering with point defects by predicting the stability of indium-vacancy clusters, InnVm. We find that the formation of large clusters is energetically favorable, which can explain the immobility of the indium ions. © 2010 Elsevier B.V. All rights reserved.

  17. Next Generation Germanium Systems for Safeguards Applications

    International Nuclear Information System (INIS)

    Dreyer, J.; Burks, M.; Hull, E.

    2015-01-01

    We are developing the latest generation of highly portable, mechanically cooled germanium systems for safeguard applications. In collaboration with our industrial partner, Ph.D.s Co, we have developed the Germanium Gamma Ray Imager (GeGI), an imager with a 2π field of view. This instrument has been thoroughly field tested in a wide range of environments and have performed reliably even in the harshest conditions. The imaging capability of GeGI complements existing safeguards techniques by allowing for the spatial detection, identification, and characterization of nuclear material. Additionally, imaging can be used in design information verification activities to address potential material diversions. Measurements conducted at the Paducah Gaseous Diffusion Plant highlight the advantages this instrument offers in the identification and localization of LEU, HEU and Pu holdup. GeGI has also been deployed to the Savannah River Site for the measurement of radioactive waste canisters, providing information valuable for waste characterization and inventory accountancy. Measuring 30 x 15 x 23 cm and weighing approximately 15 kg, this instrument is the first portable germanium-based imager. GeGI offers high reliability with the convenience of mechanical cooling, making this instrument ideal for the next generation of safeguards instrumentation. (author)

  18. Non-local electrical spin injection and detection in germanium at room temperature

    Science.gov (United States)

    Rortais, F.; Vergnaud, C.; Marty, A.; Vila, L.; Attané, J.-P.; Widiez, J.; Zucchetti, C.; Bottegoni, F.; Jaffrès, H.; George, J.-M.; Jamet, M.

    2017-10-01

    Non-local carrier injection/detection schemes lie at the very foundation of information manipulation in integrated systems. This paradigm consists in controlling with an external signal the channel where charge carriers flow between a "source" and a well separated "drain." The next generation electronics may operate on the spin of carriers in addition to their charge and germanium appears as the best hosting material to develop such a platform for its compatibility with mainstream silicon technology and the predicted long electron spin lifetime at room temperature. In this letter, we demonstrate injection of pure spin currents (i.e., with no associated transport of electric charges) in germanium, combined with non-local spin detection at 10 K and room temperature. For this purpose, we used a lateral spin valve with epitaxially grown magnetic tunnel junctions as spin injector and spin detector. The non-local magnetoresistance signal is clearly visible and reaches ≈15 mΩ at room temperature. The electron spin lifetime and diffusion length are 500 ps and 1 μm, respectively, the spin injection efficiency being as high as 27%. This result paves the way for the realization of full germanium spintronic devices at room temperature.

  19. Smooth germanium nanowires prepared by a hydrothermal deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Pei, L.Z., E-mail: lzpei1977@163.com [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Laboratory of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China); Zhao, H.S. [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Laboratory of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China); Tan, W. [Henkel Huawei Electronics Co. Ltd., Lian' yungang, Jiangsu 222006 (China); Yu, H.Y. [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Laboratory of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China); Chen, Y.W. [Department of Materials Science, Fudan University, Shanghai 200433 (China); Fan, C.G. [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Laboratory of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China); Zhang, Qian-Feng, E-mail: zhangqf@ahut.edu.cn [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Laboratory of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China)

    2009-11-15

    Smooth germanium nanowires were prepared using Ge and GeO{sub 2} as the starting materials and Cu sheet as the substrate by a simple hydrothermal deposition process. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterizations show that the germanium nanowires are smooth and straight with uniform diameter of about 150 nm in average and tens of micrometers in length. X-ray diffraction (XRD) and Raman spectrum of the germanium nanowires display that the germanium nanowires are mainly composed of cubic diamond phase. PL spectrum shows a strong blue light emission at 441 nm. The growth mechanism is also discussed.

  20. Smooth germanium nanowires prepared by a hydrothermal deposition process

    International Nuclear Information System (INIS)

    Pei, L.Z.; Zhao, H.S.; Tan, W.; Yu, H.Y.; Chen, Y.W.; Fan, C.G.; Zhang, Qian-Feng

    2009-01-01

    Smooth germanium nanowires were prepared using Ge and GeO 2 as the starting materials and Cu sheet as the substrate by a simple hydrothermal deposition process. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterizations show that the germanium nanowires are smooth and straight with uniform diameter of about 150 nm in average and tens of micrometers in length. X-ray diffraction (XRD) and Raman spectrum of the germanium nanowires display that the germanium nanowires are mainly composed of cubic diamond phase. PL spectrum shows a strong blue light emission at 441 nm. The growth mechanism is also discussed.

  1. Simulation of core-level binding energy shifts in germanium-doped lead telluride crystals

    International Nuclear Information System (INIS)

    Zyubin, A.S.; Dedyulin, S.N.; Yashina, L.V.; Shtanov, V.I.

    2007-01-01

    To simulate the changes in core-level binding energies in germanium-doped lead telluride, cluster calculations of the changes in the electrostatic potential at the corresponding centers have been performed. Different locations of the Ge atom in the crystal bulk have been considered: near vacancies, near another dopant site, and near the surface. For calculating the potential in the clusters that model the bulk and the surface of the lead telluride crystal (c-PbTe), the electron density obtained in the framework of the Hartree-Fock and hybrid density functional theory (DFT) methods has been used [ru

  2. The ATLAS Pixel Detector

    CERN Document Server

    Huegging, Fabian

    2006-06-26

    The contruction of the ATLAS Pixel Detector which is the innermost layer of the ATLAS tracking system is prgressing well. Because the pixel detector will contribute significantly to the ATLAS track and vertex reconstruction. The detector consists of identical sensor-chip-hybrid modules, arranged in three barrels in the centre and three disks on either side for the forward region. The position of the detector near the interaction point requires excellent radiation hardness, mechanical and thermal robustness, good long-term stability for all parts, combined with a low material budget. The final detector layout, new results from production modules and the status of assembly are presented.

  3. High-resolution gamma-ray measurement systems using a compact electro- mechanically cooled detector system and intelligent software

    International Nuclear Information System (INIS)

    Buckley, W.M.; Carlson, J.B.; Neufeld, K.W.

    1995-01-01

    Obtaining high-resolution gamma-ray measurements using high-purity germanium (HPGe) detectors in the field has been of limited practicality due to the need to use and maintain a supply of liquid nitrogen (LN 2 ). This same constraint limits high-resolution gamma measurements in unattended safeguards or treaty Verification applications. We are developing detectors and software to greatly extend the applicability of high-resolution germanium-based measurements for these situations

  4. iPadPix—A novel educational tool to visualise radioactivity measured by a hybrid pixel detector

    CERN Document Server

    Keller, O; Müller, A; Benoit, M

    2016-01-01

    With the ability to attribute signatures of ionising radiation to certain particle types, pixel detectors offer a unique advantage over the traditional use of Geiger-Müller tubes also in educational settings. We demonstrate in this work how a Timepix readout chip combined with a standard 300 μ m pixelated silicon sensor can be used to visualise radioactivity in real-time and by means of augmented reality. The chip family is the result of technology transfer from High Energy Physics at CERN and facilitated by the Medipix Collaboration. This article summarises the development of a prototype based on an iPad mini and open source software detailed in ref. [1]. Appropriate experimental activities that explore natural radioactivity and everyday objects are given to demonstrate the use of this new tool in educational settings.

  5. iPadPix—A novel educational tool to visualise radioactivity measured by a hybrid pixel detector

    International Nuclear Information System (INIS)

    Keller, O.; Schmeling, S.; Müller, A.; Benoit, M.

    2016-01-01

    With the ability to attribute signatures of ionising radiation to certain particle types, pixel detectors offer a unique advantage over the traditional use of Geiger-Müller tubes also in educational settings. We demonstrate in this work how a Timepix readout chip combined with a standard 300μm pixelated silicon sensor can be used to visualise radioactivity in real-time and by means of augmented reality. The chip family is the result of technology transfer from High Energy Physics at CERN and facilitated by the Medipix Collaboration. This article summarises the development of a prototype based on an iPad mini and open source software detailed in ref. [1]. Appropriate experimental activities that explore natural radioactivity and everyday objects are given to demonstrate the use of this new tool in educational settings.

  6. Ge Detector Data Classification with Neural Networks

    Science.gov (United States)

    Wilson, Carly; Martin, Ryan; Majorana Collaboration

    2014-09-01

    The Majorana Demonstrator experiment is searching for neutrinoless double beta-decay using p-type point contact PPC germanium detectors at the Sanford Underground Research Facility, in South Dakota. Pulse shape discrimination can be used in PPC detectors to distinguish signal-like events from backgrounds. This research program explored the possibility of building a self-organizing map that takes data collected from germanium detectors and classifies the events as either signal or background. Self organizing maps are a type of neural network that are self-learning and less susceptible to being biased from imperfect training data. We acknowledge support from the Office of Nuclear Physics in the DOE Office of Science, the Particle and Nuclear Astrophysics Program of the National Science Foundation and the Russian Foundation for Basic Research.

  7. Nanoscale resonant-cavity-enhanced germanium photodetectors with lithographically defined spectral response for improved performance at telecommunications wavelengths.

    Science.gov (United States)

    Balram, Krishna C; Audet, Ross M; Miller, David A B

    2013-04-22

    We demonstrate the use of a subwavelength planar metal-dielectric resonant cavity to enhance the absorption of germanium photodetectors at wavelengths beyond the material's direct absorption edge, enabling high responsivity across the entire telecommunications C and L bands. The resonant wavelength of the detectors can be tuned linearly by varying the width of the Ge fin, allowing multiple detectors, each resonant at a different wavelength, to be fabricated in a single-step process. This approach is promising for the development of CMOS-compatible devices suitable for integrated, high-speed, and energy-efficient photodetection at telecommunications wavelengths.

  8. Effects of electronically neutral impurities on muonium in germanium

    International Nuclear Information System (INIS)

    Clawson, C.W.; Crowe, K.M.; Haller, E.E.; Rosenblum, S.S.; Brewer, J.H.

    1983-04-01

    Low-temperature measurements of muonium parameters in various germanium crystals have been performed. We have measured crystals with different levels of neutral impurities, with and without dislocations, and with different annealing histories. The most striking result is the apparent trapping of Mu by silicon impurities in germanium

  9. Imaging capabilities of germanium gamma cameras

    International Nuclear Information System (INIS)

    Steidley, J.W.

    1977-01-01

    Quantitative methods of analysis based on the use of a computer simulation were developed and used to investigate the imaging capabilities of germanium gamma cameras. The main advantage of the computer simulation is that the inherent unknowns of clinical imaging procedures are removed from the investigation. The effects of patient scattered radiation were incorporated using a mathematical LSF model which was empirically developed and experimentally verified. Image modifying effects of patient motion, spatial distortions, and count rate capabilities were also included in the model. Spatial domain and frequency domain modeling techniques were developed and used in the simulation as required. The imaging capabilities of gamma cameras were assessed using low contrast lesion source distributions. The results showed that an improvement in energy resolution from 10% to 2% offers significant clinical advantages in terms of improved contrast, increased detectability, and reduced patient dose. The improvements are of greatest significance for small lesions at low contrast. The results of the computer simulation were also used to compare a design of a hypothetical germanium gamma camera with a state-of-the-art scintillation camera. The computer model performed a parametric analysis of the interrelated effects of inherent and technological limitations of gamma camera imaging. In particular, the trade-off between collimator resolution and collimator efficiency for detection of a given low contrast lesion was directly addressed. This trade-off is an inherent limitation of both gamma cameras. The image degrading effects of patient motion, camera spatial distortions, and low count rate were shown to modify the improvements due to better energy resolution. Thus, based on this research, the continued development of germanium cameras to the point of clinical demonstration is recommended

  10. Tensile strain mapping in flat germanium membranes

    International Nuclear Information System (INIS)

    Rhead, S. D.; Halpin, J. E.; Myronov, M.; Patchett, D. H.; Allred, P. S.; Wilson, N. R.; Leadley, D. R.; Shah, V. A.; Kachkanov, V.; Dolbnya, I. P.; Reparaz, J. S.; Sotomayor Torres, C. M.

    2014-01-01

    Scanning X-ray micro-diffraction has been used as a non-destructive probe of the local crystalline quality of a thin suspended germanium (Ge) membrane. A series of reciprocal space maps were obtained with ∼4 μm spatial resolution, from which detailed information on the strain distribution, thickness, and crystalline tilt of the membrane was obtained. We are able to detect a systematic strain variation across the membranes, but show that this is negligible in the context of using the membranes as platforms for further growth. In addition, we show evidence that the interface and surface quality is improved by suspending the Ge

  11. Tensile strain mapping in flat germanium membranes

    Energy Technology Data Exchange (ETDEWEB)

    Rhead, S. D., E-mail: S.Rhead@warwick.ac.uk; Halpin, J. E.; Myronov, M.; Patchett, D. H.; Allred, P. S.; Wilson, N. R.; Leadley, D. R. [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Shah, V. A. [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Department of Engineering, University of Warwick, Coventry, CV4 7AL (United Kingdom); Kachkanov, V.; Dolbnya, I. P. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE (United Kingdom); Reparaz, J. S. [ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona) (Spain); Sotomayor Torres, C. M. [ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona) (Spain)

    2014-04-28

    Scanning X-ray micro-diffraction has been used as a non-destructive probe of the local crystalline quality of a thin suspended germanium (Ge) membrane. A series of reciprocal space maps were obtained with ∼4 μm spatial resolution, from which detailed information on the strain distribution, thickness, and crystalline tilt of the membrane was obtained. We are able to detect a systematic strain variation across the membranes, but show that this is negligible in the context of using the membranes as platforms for further growth. In addition, we show evidence that the interface and surface quality is improved by suspending the Ge.

  12. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed

    2014-07-29

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  13. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed; Rubin, Andrew; Refaat, Mohamed; Sedky, Sherif; Abdo, Mohammad

    2014-01-01

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  14. Detector for atomic particles and ionizing radiations

    International Nuclear Information System (INIS)

    Mallet, Georges; Ythier, Christian.

    1976-01-01

    The aim of this invention is to provide improved detectors of atomic particles and of ionising radiations, having maximum sensitivity, by virtually suppressing all absorption of the radiation scattered by the main detector, so that these detectors are particularly suitable for fitting to anti-Compton spectrometers. Reference is particularly made to detectors of the Ge(Li) type, lithium compensated germanium, which are the most used. It is however made clear that this choice is not restrictive and that this invention not only applies to all known types of detectors and particularly to scintillator detectors, for instance to detectors such as NaI (Tl), composed of a monocrystal of a thallium activated alkaline halogenide, but also to gas, ionisation chamber and luminescent chamber type detectors and in general to all the known devices that convert the energy of particles into electric signals. Owing to the fact that the walls of the enclosure containing the main detector are composed, in the part around this detector, of an auxiliary detector, the latter detects virtually all the radiations scattered by the main detector. It does so without any loss due to the absorption of these radiations (a) by the metal walls of the enclosure usually containing the main detector and (b) by the walls of the auxiliary detector casing. It results from this that the detectors of the invention enable coincidence or anti-coincidence spectrometers with a very high performance to be made [fr

  15. Double hypernuclei experiment with hybrid emulsion method at J-PARC

    International Nuclear Information System (INIS)

    Ekawa, Hiroyuki

    2015-01-01

    Double hypernuclei are important probes to study the system with strangeness S = -2. Several emulsion experiments had been performed to search for them. We are planning a new experiment to search for double hypernuclei at the K1.8 beam line in the Hadron Experimental Facility (J-PARC E07 experiment). Ξ"- tracks in the emulsion plates and SSD will be automatically connected by a hybrid method. The estimated Ξ"- stopped statistics is 10 times as high as that of the KEK E373 experiment. Discoveries of 10 new double hypernuclear species are expected, which enable us to discuss binding energy in terms of mass number dependence. On the other hand, we will also observe X rays from Ξ"- atoms with a germanium detector array installed close to the emulsion plates by tagging Ξ"- stopped events. This will be the first measurement to give information on the Ξ"- potential at the nuclear surface region. (author)

  16. Simulation of single-event energy-deposition spreading in a hybrid pixellated detector for gamma imaging

    CERN Document Server

    Manach, E

    2002-01-01

    In the framework of the Medipix2 Collaboration, a new photon-counting chip is being developed made of a 256x256 array of 55 mu m-side square pixels. Although the chip was primarily developed for semiconductor X-ray imagers, we think that this type of device could be used in applications such as decommissioning of nuclear facilities where typical sources have gamma-ray energies in the range of a few hundred keV. In order to enhance the detection efficiency in this energy range, we envisage connecting the Medipix2 chip to a CdTe or CdZnTe substrate (at least 1 mm thick). The small pixel size, the thickness of the Cd(Zn)Te substrate and the high photon energy motivate us to estimate first the spatial energy spreading following a photon interaction inside the detector. Estimations were made using the MCNP Monte Carlo package by simulating the individual energy distribution for each primary photon interaction. As an illustration of our results, simulating a 660 keV gamma source, we found that there are two pixels ...

  17. Design and Characterization of a Gradient-Transparent RF Copper Shield for PET Detector Modules in Hybrid MR-PET Imaging

    Science.gov (United States)

    Berneking, Arne; Trinchero, Riccardo; Ha, YongHyun; Finster, Felix; Cerello, Piergiorgio; Lerche, Christoph; Shah, Nadim Jon

    2017-05-01

    This paper focuses on the design and the characterization of a frequency-selective shield for positron emission tomography (PET) detector modules of hybrid magnetic resonance-PET scanners, where the shielding of the PET cassettes is located close to the observed object. The proposed shielding configuration is designed and optimized to guarantee a high shielding effectiveness (SE) of up to 60 dB for B1-fields at the Larmor frequency of 64 MHz, thus preventing interactions between the radio-frequency (RF) coil and PET electronics. On the other hand, the shield is transparent to the gradient fields with the consequence that eddy-current artifacts in the acquired EPI images are significantly reduced with respect to the standard solid-shield configuration. The frequency-selective behavior of the shield is characterized and validated via simulation studies with CST MICROWAVE STUDIO in the megahertz and kilohertz range. Bench measurements with an RF coil built in-house demonstrated the high SE at the Larmor frequency. Moreover, measurements on a 4-T human scanner confirmed the abolishment of eddy current artifact and also provided an understanding of where the eddy currents occur with respect to the sequence parameters. Simulations and measurements for the proposed shielding concept were compared with a solid copper shielding configuration.

  18. Doping of germanium telluride with bismuth tellurides

    International Nuclear Information System (INIS)

    Abrikosov, N.Kh.; Karpinskij, O.G.; Makalatiya, T.Sh.; Shelimova, L.E.

    1981-01-01

    Effect of germanium telluride doping with bismuth fellurides (Bi 2 Te 3 ; BiTe; Bi 2 Te) on phase transition temperature, lattice parameters and electrophysical properties of alloys is studied. It is shown that in alloys of GeTe-Bi 2 Te 3 (BiTe)(Bi 2 Te) cross sections solid solution of GeTe with Bi 2 Te 3 , characterized by deviation from stoichiometry, and germanium in the second phase the quantity of which increases during the transition from GeTe-Bi 2 Te 3 cross section to GeTe-Bi 2 Te are in equilibrium. Lower values of holes concentration and of electric conductivity and higher values of thermo e.m.f. coefficient in comparison with alloys of GeTe-Bi 2 Te 3 cross section with the same bismuth content are characterized for GeTe-Bi 2 Te cross section alloys. It is shown that in the range of GeTe-base solid solution the α→γ phase transformation which runs trough the two-phase region (α→γ) is observed with tellurium content increase. Extension of α-phase existence region widens with the bismuth content increase. Peculiarities of interatomic interaction in GeTe-base solid solutions with isovalent and heterovalent cation substitution are considered [ru

  19. GeMini: The Next Generation Mechanically-Cooled Germanium Spectrometer

    International Nuclear Information System (INIS)

    Burks, M.

    2008-01-01

    The next-generation mechanically-cooled germanium spectrometer has been developed. GeMini (GErmanium MINIature spectrometer) has been designed to bring high-resolution gamma-ray spectroscopy to a range of demanding field environments. Intended applications include short-notice and surprise inspections where positive nuclide identification of radioactive materials is required. GeMini weighs 2.75 kg (6 lbs) total including the detector, cryostat, cryocooler, batteries, electronics and readout. It is very low power allowing it to operate for 10 hours on a single set of rechargeable batteries. This instrument employs technology adapted from the gamma-ray spectrometer currently flying on NASA's Mercury MESSENGER spacecraft. Specifically, infrared shielding techniques allow for a vast reduction of thermal load. This in turn allows for a smaller, lighter-weight design, well-suited for a hand-held instrument. Two working prototypes have been built and tested in the lab. The target energy resolution is 3 keV fwhm or better for 1332 keV gamma-rays. The detectors currently achieve around 4.5 keV resolution, which is slightly higher than our goal due to microphonic noise. Our present work focuses on improving the resolution through mechanical and electronic means of reducing the microphonic noise. This paper will focus on the performance of the instrument and its applicability for inspectors in the field

  20. Improved performance of photoconductive gain hybrid UV detector by trap state engineering of ZnO nanoparticles

    Science.gov (United States)

    Azadinia, M.; Fathollahi, M. R.; Mosadegh, M.; Boroumand, F. A.; Mohajerani, E.

    2017-10-01

    With the purpose of examining the impact of donor polymer on the performance of nanocomposite photodetectors (PDs) and to better understand the underlying physics, different wide-bandgap semiconducting polymers, poly(N-vinylcarbazole), poly(9, 9-di-n-octylfluorenyl-2, 7-diyl) , and [9,9'-dioctyl-fluorene-2,7-diyl]-copoly[diphenyl-p-tolyl-amine-4,4'-diyl] (BFE), are mixed with ZnO nanoparticles (NPs) to fabricate hybrid UV PDs. Three different polymer matrix nanocomposites were investigated that differ in the electron-trap depth in the nanocomposite and also the carrier tunneling energy at the interface. All the fabricated PDs exhibit strong photoconductive gain characteristics which can be attributed to trapped electron accumulation and band bending at the cathode interface. Experimental results show that the manipulation of the photoactive nanocomposite improves the PD properties simultaneously, namely, the external quantum efficiency (EQE, ˜104%), the maximum detectivity (D*, ˜1013 Jones), and the linear dynamic range (LDR, ˜85 dB). In addition, the gain bandwidth product of the device improves more than 50 times. Furthermore, the effect of the photogenerated carrier profile within the active layer is investigated experimentally by changing the direction of the incident light using a transparent cathode. Interestingly, under illumination through the Al cathode, faster photocurrent response, wider spectral range toward the deep UV region, and higher EQE in relatively low voltages are observed. These considerations might provide a general strategy to fabricate low-cost photoconductive PDs with a reasonably good combination of gain, response speed, LDR, and selectivity.

  1. High-purity germanium detection system for the in vivo measurement of americium and plutonium

    International Nuclear Information System (INIS)

    Tyree, W.H.; Falk, R.B.; Wood, C.B.; Liskey, R.W.

    1976-01-01

    A high-purity germanium (HPGe) array, photon-counting system has been developed for the Rocky Flats Plant Body-Counter Medical Facility. The newly improved system provides exceptional resolutions of low-energy X-ray and gamma-ray spectra associated with the in vivo deposition of plutonium and americium. Described are the operational parameters of the system and some qualitative results illustrating detector performance for the photon emissions produced from the decay of plutonium and americium between energy ranges from 10 to 100 kiloelectron volts. Since large amounts of data are easily generated with the system, data storage, analysis, and computer software developments continue to be an essential ingredient for processing spectral data obtained from the detectors. Absence of quantitative data is intentional. The primary concern of the study was to evaluate the effects of the various physical and electronic operational parameters before adding those related entirely to a human subject

  2. Production, characterization and operation of {sup 76}Ge enriched BEGe detectors in GERDA

    Energy Technology Data Exchange (ETDEWEB)

    Agostini, M.; Bode, T.; Budjas, D.; Janicsko Csathy, J.; Lazzaro, A.; Schoenert, S. [Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); Allardt, M.; Barros, N.; Domula, A.; Lehnert, B.; Wester, T.; Wilsenach, H.; Zuber, K. [Technische Universitaet Dresden, Institut fuer Kern- und Teilchenphysik, Dresden (Germany); Andreotti, E. [Institute for Reference Materials and Measurements, Geel (Belgium); Eberhard Karls Universitaet Tuebingen, Physikalisches Institut, Tuebingen (Germany); Bakalyarov, A.M.; Belyaev, S.T.; Lebedev, V.I.; Zhukov, S.V. [National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Balata, M.; D' Andrea, V.; Ioannucci, L.; Junker, M.; Laubenstein, M.; Macolino, C.; Nisi, S.; Zavarise, P. [INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi (Italy); Barabanov, I.; Bezrukov, L.; Gurentsov, V.; Inzhechik, L.V.; Kazalov, V.; Kuzminov, V.V.; Lubsandorzhiev, B.; Yanovich, E. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Baudis, L.; Benato, G.; Walter, M. [Physik Institut der Universitaet Zuerich, Zurich (Switzerland); Bauer, C.; Heisel, M.; Heusser, G.; Hofmann, W.; Kihm, T.; Kirsch, A.; Knoepfle, K.T.; Lindner, M.; Maneschg, W.; Salathe, M.; Schreiner, J.; Schwingenheuer, B.; Simgen, H.; Smolnikov, A.; Strecker, H.; Wagner, V.; Wegmann, A. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Becerici-Schmidt, N.; Caldwell, A.; Liao, H.Y.; Majorovits, B.; O' Shaughnessy, C.; Palioselitis, D.; Schulz, O.; Vanhoefer, L. [Max-Planck-Institut fuer Physik, Munich (Germany); Bellotti, E.; Pessina, G. [Universita Milano Bicocca, Dipartimento di Fisica, Milan (Italy); INFN Milano Bicocca, Milan (Italy); Belogurov, S.; Kornoukhov, V.N. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Bettini, A.; Brugnera, R.; Garfagnini, A.; Hemmer, S.; Sada, C.; Von Sturm, K. [Dipartimento di Fisica e Astronomia dell' Universita di Padova, Padua (Italy); INFN Padova, Padua (Italy); Borowicz, D. [Jagiellonian University, Institute of Physics, Cracow (Poland); Joint Institute for Nuclear Research, Dubna (Russian Federation); Brudanin, V.; Egorov, V.; Kochetov, O.; Nemchenok, I.; Rumyantseva, N.; Shevchik, E.; Zhitnikov, I.; Zinatulina, D. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Cattadori, C.; Gotti, C. [INFN Milano Bicocca, Milan (Italy); Chernogorov, A.; Demidova, E.V.; Kirpichnikov, I.V.; Vasenko, A.A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Falkenstein, R.; Freund, K.; Grabmayr, P.; Hegai, A.; Jochum, J.; Schmitt, C.; Schuetz, A.K. [Eberhard Karls Universitaet Tuebingen, Physikalisches Institut, Tuebingen (Germany); Frodyma, N.; Misiaszek, M.; Pelczar, K.; Wojcik, M.; Zuzel, G. [Jagiellonian University, Institute of Physics, Cracow (Poland); Gangapshev, A. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Gusev, K. [Joint Institute for Nuclear Research, Dubna (Russian Federation); National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); Hult, M.; Lutter, G. [Institute for Reference Materials and Measurements, Geel (Belgium); Klimenko, A.; Lubashevskiy, A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Lippi, I.; Stanco, L.; Ur, C.A. [INFN Padova, Padua (Italy); Pandola, L. [INFN Laboratori Nazionali del Sud, Catania (Italy); Pullia, A.; Riboldi, S. [Universita degli Studi di Milano, Dipartimento di Fisica, Milan (Italy); INFN Milano (Italy); Shirchenko, M. [Joint Institute for Nuclear Research, Dubna (Russian Federation); National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Collaboration: GERDA Collaboration

    2015-02-01

    The GERmanium Detector Array (GERDA) at the Gran Sasso Underground Laboratory (LNGS) searches for the neutrinoless double beta decay (0νββ) of {sup 76}Ge. Germanium detectors made of material with an enriched {sup 76}Ge fraction act simultaneously as sources and detectors for this decay. During Phase I of the experiment mainly refurbished semi-coaxial Ge detectors from former experiments were used. For the upcoming Phase II, 30 new {sup 76}Ge enriched detectors of broad energy germanium (BEGe)- type were produced. A subgroup of these detectors has already been deployed in GERDA during Phase I. The present paper reviews the complete production chain of these BEGe detectors including isotopic enrichment, purification, crystal growth and diode production. The efforts in optimizing the mass yield and in minimizing the exposure of the {sup 76}Ge enriched germanium to cosmic radiation during processing are described. Furthermore, characterization measurements in vacuum cryostats of the first subgroup of seven BEGe detectors and their long-term behavior in liquid argon are discussed. The detector performance fulfills the requirements needed for the physics goals of GERDA Phase II. (orig.)

  3. Production, characterization and operation of {sup 76}Ge enriched BEGe detectors in GERDA

    Energy Technology Data Exchange (ETDEWEB)

    Agostini, M. [Physik Department and Excellence Cluster Universe, Technische Universität München, Munich (Germany); Allardt, M. [Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Dresden (Germany); Andreotti, E. [Institute for Reference Materials and Measurements, Geel (Belgium); Physikalisches Institut, Eberhard Karls Universität Tübingen, Tübingen (Germany); Bakalyarov, A. M. [National Research Centre “Kurchatov Institute”, Moscow (Russian Federation); Balata, M. [INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi (Italy); and others

    2015-02-03

    The GERmanium Detector Array (Gerda) at the Gran Sasso Underground Laboratory (LNGS) searches for the neutrinoless double beta decay (0νββ) of {sup 76}Ge. Germanium detectors made of material with an enriched {sup 76}Ge fraction act simultaneously as sources and detectors for this decay. During Phase I of theexperiment mainly refurbished semi-coaxial Ge detectors from former experiments were used. For the upcoming Phase II, 30 new {sup 76}Ge enriched detectors of broad energy germanium (BEGe)-type were produced. A subgroup of these detectors has already been deployed in Gerda during Phase I. The present paper reviews the complete production chain of these BEGe detectors including isotopic enrichment, purification, crystal growth and diode production. The efforts in optimizing the mass yield and in minimizing the exposure of the {sup 76}Ge enriched germanium to cosmic radiation during processing are described. Furthermore, characterization measurements in vacuum cryostats of the first subgroup of seven BEGe detectors and their long-term behavior in liquid argon are discussed. The detector performance fulfills the requirements needed for the physics goals of Gerda Phase II.

  4. Production, characterization and operation of Ge enriched BEGe detectors in GERDA

    Science.gov (United States)

    Agostini, M.; Allardt, M.; Andreotti, E.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Domula, A.; Egorov, V.; Falkenstein, R.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gotti, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Misiaszek, M.; Nemchenok, I.; Nisi, S.; O'Shaughnessy, C.; Palioselitis, D.; Pandola, L.; Pelczar, K.; Pessina, G.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salathe, M.; Schmitt, C.; Schreiner, J.; Schulz, O.; Schütz, A.-K.; Schwingenheuer, B.; Schönert, S.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Strecker, H.; Ur, C. A.; Vanhoefer, L.; Vasenko, A. A.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wilsenach, H.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2015-02-01

    The GERmanium Detector Array ( Gerda) at the Gran Sasso Underground Laboratory (LNGS) searches for the neutrinoless double beta decay () of Ge. Germanium detectors made of material with an enriched Ge fraction act simultaneously as sources and detectors for this decay. During Phase I of theexperiment mainly refurbished semi-coaxial Ge detectors from former experiments were used. For the upcoming Phase II, 30 new Ge enriched detectors of broad energy germanium (BEGe)-type were produced. A subgroup of these detectors has already been deployed in Gerda during Phase I. The present paper reviews the complete production chain of these BEGe detectors including isotopic enrichment, purification, crystal growth and diode production. The efforts in optimizing the mass yield and in minimizing the exposure of the Ge enriched germanium to cosmic radiation during processing are described. Furthermore, characterization measurements in vacuum cryostats of the first subgroup of seven BEGe detectors and their long-term behavior in liquid argon are discussed. The detector performance fulfills the requirements needed for the physics goals of Gerda Phase II.

  5. Oxygen defect processes in silicon and silicon germanium

    KAUST Repository

    Chroneos, A.; Sgourou, E. N.; Londos, C. A.; Schwingenschlö gl, Udo

    2015-01-01

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  6. Oxygen defect processes in silicon and silicon germanium

    KAUST Repository

    Chroneos, A.

    2015-06-18

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  7. Interactions of germanium atoms with silica surfaces

    International Nuclear Information System (INIS)

    Stanley, Scott K.; Coffee, Shawn S.; Ekerdt, John G.

    2005-01-01

    GeH 4 is thermally cracked over a hot filament depositing 0.7-15 ML Ge onto 2-7 nm SiO 2 /Si(1 0 0) at substrate temperatures of 300-970 K. Ge bonding changes are analyzed during annealing with X-ray photoelectron spectroscopy. Ge, GeH x , GeO, and GeO 2 desorption is monitored through temperature programmed desorption in the temperature range 300-1000 K. Low temperature desorption features are attributed to GeO and GeH 4 . No GeO 2 desorption is observed, but GeO 2 decomposition to Ge through high temperature pathways is seen above 750 K. Germanium oxidization results from Ge etching of the oxide substrate. With these results, explanations for the failure of conventional chemical vapor deposition to produce Ge nanocrystals on SiO 2 surfaces are proposed

  8. Investigation about semiconductor gamma ray detector - Evaluation of Ge(Li) detectors life expectation

    International Nuclear Information System (INIS)

    1980-06-01

    A list of germanium lithium gamma ray detectors has been drawn up by a working group after investigations in various laboratories. Authors analyse the historical account of each detector and try to give an answer about some questions as: - detectors life expectation, - deficiencies and death reasons, - influence of detector type and volume. Differents parameters are also collected by the working group for future works (standard geometry, low level measurements, etc.). In the list, the characteristics of 228 detectors, collected between january 1965 and december 1977 are put together. The principal conclusions of the authors are: - with a probability of 95%, half of the detectors is dead before 6.1 years, - the average age of dead population (33% of detectors) is 3.9 years, - resolution and efficiency evolution are good indicators of possible deficiency, - the fiability of vertical cryostat is better than the other systems [fr

  9. Radiation-electromagnetic effect in germanium monocrystals

    International Nuclear Information System (INIS)

    Kikoin, I.K.; Kikoin, L.I.; Lazarev, S.D.

    1980-01-01

    Experimentally investigated is the radiation-electromagnetic effect (REM) in germanium monocrystals on excitation of excess current carriers by α particles, protons and X-rays in magnetic fields up to 8 kOe. A cyclotron was used as an α particle source, and a standard X-ray tube with a copper anode - as an X-ray source. The e.m.f. of the REM effect linearly increases with the increase of the magnetic field and is proportional to the charged particle flux at small flux values, saturation occurs at great flux values (approximately 5x10 11 part./cm 2 xs). In the 4-40 MeV energy range the e.m.f. of the REM effect practically does not depend on the α particle energy. On irradiation of the samples with a grinding front surface the REM e.m.f. changes its sign. The REM and Hall effect measurement on α particle irradiated samples has shown that during irradiation a p-n transition is formed in the samples, which must be taken into account while studying the REM effect. The e.m.f. measured for the even REM effect quadratically increases with the magnetic field increase. The barrier radiation-voltaic effect (the effect e.m.f. is measured between the irradiated and nonirradiated sample faces) is studied. Using special masks the samples with a set of consecutive p-n transitions are produced by irradiation of germanium crystals by α particles. Investigation of the photovoltaic and photoelectromagnetic effects on such samples has shown that using this method the efficiency of the REM devices can be increased

  10. Reduction of Defects in Germanium-Silicon

    Science.gov (United States)

    2003-01-01

    Crystals grown without contact with a container have far superior quality to otherwise similar crystals grown in direct contact with a container. In addition to float-zone processing, detached- Bridgman growth is a promising tool to improve crystal quality, without the limitations of float zoning or the defects introduced by normal Bridgman growth. Goals of this project include the development of the detached Bridgman process to be reproducible and well understood and to quantitatively compare the defect and impurity levels in crystals grown by these three methods. Germanium (Ge) and germanium-silicon (Ge-Si) alloys are being used. At MSFC, we are responsible for the detached Bridgman experiments intended to differentiate among proposed mechanisms of detachment, and to confirm or refine our understanding of detachment. Because the contact angle is critical to determining the conditions for detachment, the sessile drop method was used to measure the contact angles as a function of temperature and composition for a large number of substrates made of potential ampoule materials. Growth experiments have used pyrolytic boron nitride (pBN) and fused silica ampoules with the majority of the detached results occurring predictably in the pBN. Etch pit density (EPD) measurements of normal and detached Bridgman-grown Ge samples show a two order of magnitude improvement in the detached-grown samples. The nature and extent of detachment is determined by using profilometry in conjunction with optical and electron microscopy. The stability of detachment has been analyzed, and an empirical model for the conditions necessary to achieve sufficient stability to maintain detached growth for extended periods has been developed. We have investigated the effects on detachment of ampoule material, pressure difference above and below the melt, and Si concentration; samples that are nearly completely detached can be grown repeatedly in pBN. Current work is concentrated on developing a

  11. Silicon and Germanium (111) Surface Reconstruction

    Science.gov (United States)

    Hao, You Gong

    Silicon (111) surface (7 x 7) reconstruction has been a long standing puzzle. For the last twenty years, various models were put forward to explain this reconstruction, but so far the problem still remains unsolved. Recent ion scattering and channeling (ISC), scanning tunneling microscopy (STM) and transmission electron diffraction (TED) experiments reveal some new results about the surface which greatly help investigators to establish better models. This work proposes a silicon (111) surface reconstruction mechanism, the raising and lowering mechanism which leads to benzene -like ring and flower (raised atom) building units. Based on these building units a (7 x 7) model is proposed, which is capable of explaining the STM and ISC experiment and several others. Furthermore the building units of the model can be used naturally to account for the germanium (111) surface c(2 x 8) reconstruction and other observed structures including (2 x 2), (5 x 5) and (7 x 7) for germanium as well as the (/3 x /3)R30 and (/19 x /19)R23.5 impurity induced structures for silicon, and the higher temperature disordered (1 x 1) structure for silicon. The model is closely related to the silicon (111) surface (2 x 1) reconstruction pi-bonded chain model, which is the most successful model for the reconstruction now. This provides an explanation for the rather low conversion temperature (560K) of the (2 x 1) to the (7 x 7). The model seems to meet some problems in the explanation of the TED result, which is explained very well by the dimer, adatom and stacking fault (DAS) model proposed by Takayanagi. In order to explain the TED result, a variation of the atomic scattering factor is proposed. Comparing the benzene-like ring model with the DAS model, the former needs more work to explain the TED result and the later has to find a way to explain the silicon (111) surface (1 x 1) disorder experiment.

  12. Search for photons with energies above 10{sup 18} eV using the hybrid detector of the Pierre Auger Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Aab, A. [Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud Universiteit, Nijmegen (Netherlands); Abreu, P.; Andringa, S. [Laboratório de Instrumentação e Física Experimental de Partículas—LIP and Instituto Superior Técnico—IST, Universidade de Lisboa—UL (Portugal); Aglietta, M. [Osservatorio Astrofisico di Torino (INAF), Torino (Italy); Samarai, I. Al [Laboratoire de Physique Nucléaire et de Hautes Energies (LPNHE), Universités Paris 6 et Paris 7, CNRS-IN2P3 (France); Albuquerque, I.F.M. [Universidade de São Paulo, Inst. de Física, São Paulo (Brazil); Allekotte, I. [Centro Atómico Bariloche and Instituto Balseiro (CNEA-UNCuyo-CONICET) (Argentina); Almela, A.; Andrada, B. [Instituto de Tecnologías en Detección y Astropartículas (CNEA, CONICET, UNSAM), Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica (Argentina); Castillo, J. Alvarez [Universidad Nacional Autónoma de México, México (Mexico); Alvarez-Muñiz, J. [Universidad de Santiago de Compostela (Spain); Anastasi, G.A. [Gran Sasso Science Institute (INFN), L' Aquila (Italy); Anchordoqui, L., E-mail: auger_spokespersons@fnal.gov [Department of Physics and Astronomy, Lehman College, City University of New York (United States); and others

    2017-04-01

    A search for ultra-high energy photons with energies above 1 EeV is performed using nine years of data collected by the Pierre Auger Observatory in hybrid operation mode. An unprecedented separation power between photon and hadron primaries is achieved by combining measurements of the longitudinal air-shower development with the particle content at ground measured by the fluorescence and surface detectors, respectively. Only three photon candidates at energies 1–2 EeV are found, which is compatible with the expected hadron-induced background. Upper limits on the integral flux of ultra-high energy photons of 0.027, 0.009, 0.008, 0.008 and 0.007 km{sup −2} sr{sup −1} yr{sup −1} are derived at 95% C.L. for energy thresholds of 1, 2, 3, 5 and 10 EeV. These limits bound the fractions of photons in the all-particle integral flux below 0.1%, 0.15%, 0.33%, 0.85% and 2.7%. For the first time the photon fraction at EeV energies is constrained at the sub-percent level. The improved limits are below the flux of diffuse photons predicted by some astrophysical scenarios for cosmogenic photon production. The new results rule-out the early top-down models − in which ultra-high energy cosmic rays are produced by, e.g., the decay of super-massive particles − and challenge the most recent super-heavy dark matter models.

  13. Gamma radiation detectors for safeguards applications

    International Nuclear Information System (INIS)

    Carchon, R.; Moeslinger, M.; Bourva, L.; Bass, C.; Zendel, M.

    2007-01-01

    The IAEA uses extensively a variety of gamma radiation detectors to verify nuclear material. These detectors are part of standardized spectrometry systems: germanium detectors for High-Resolution Gamma Spectrometry (HRGS); Cadmium Zinc Telluride (CZT) detectors for Room Temperature Gamma Spectrometry (RTGS); and NaI(Tl) detectors for Low Resolution Gamma Spectrometry (LRGS). HRGS with high-purity Germanium (HpGe) detectors cooled by liquid nitrogen is widely used in nuclear safeguards to verify the isotopic composition of plutonium or uranium in non-irradiated material. Alternative cooling systems have been evaluated and electrically cooled HpGe detectors show a potential added value, especially for unattended measurements. The spectrometric performance of CZT detectors, their robustness and simplicity are key to the successful verification of irradiated materials. Further development, such as limiting the charge trapping effects in CZT to provide improved sensitivity and energy resolution are discussed. NaI(Tl) detectors have many applications-specifically in hand-held radioisotope identification devices (RID) which are used to detect the presence of radioactive material where a lower resolution is sufficient, as they benefit from a generally higher sensitivity. The Agency is also continuously involved in the review and evaluation of new and emerging technologies in the field of radiation detection such as: Peltier-cooled CdTe detectors; semiconductor detectors operating at room temperature such as HgI 2 and GaAs; and, scintillator detectors using glass fibres or LaBr 3 . A final conclusion, proposing recommendations for future action, is made

  14. SiGe Intersubband Detectors for Terahertz Communication and Sensing

    National Research Council Canada - National Science Library

    Kolodzey, James

    2003-01-01

    We report on the design and fabrication of THz detectors based on silicon germanium nanostructures grown by MBE to obtain intersubband transitions in the energy range from 4.1 meV to 4.1 meV (1 to 10 THz...

  15. Lattice site and thermal stability of transition metals in germanium

    CERN Document Server

    Augustyns, Valérie; Pereira, Lino

    Although the first transistor was based on germanium, current chip technology mainly uses silicon due to its larger abundance, a lower price and higher quality silicon-oxide. However, a very important goal in microelectronics is to obtain faster integrated circuits. The advantages of germanium compared to silicon (e.g. a higher mobility of the charge carriers) motivates further research on germanium based materials. Semiconductor doping (e.g. introducing impurities into silicon and germanium in order to alter - and control - their properties) can be done by ion implantation or by in situ doping, whereby the host material is doped during growth. This thesis focuses on introducing dopants by ion implantation. The implantation as well as the subsequent measurements were performed in ISOLDE (CERN) using the emission channeling technique. Although ion implantation generates undesired defects in the host material (e.g. vacancies), such damage can be reduced by performing the implantation at an elevated temperature....

  16. Vacancy-acceptor complexes in germanium produced by ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Feuser, U.; Vianden, R. (Inst. fuer Strahlen- und Kernphysik, Univ. Bonn (Germany)); Alves, E.; Silva, M.F. da (Dept. de Fisica, ICEN/LNETI, Sacavem (Portugal)); Szilagyi, E.; Paszti, F. (Central Research Inst. for Physics, Hungarian Academy of Sciences, Budapest (Hungary)); Soares, J.C. (Centro de Fisica Nuclear, Univ. Lisbon (Portugal))

    1991-07-01

    Combining results obtained by the {gamma}-{gamma} perturbed angular correlation method, Rutherford backscattering and elastic recoil detection of hydrogen, a defect complex formed in germanium by indium implantation is identified as a vacancy trapped by the indium probe. (orig.).

  17. Radiation Hardening of Silicon Detectors

    CERN Multimedia

    Leroy, C; Glaser, M

    2002-01-01

    %RD48 %title\\\\ \\\\Silicon detectors will be widely used in experiments at the CERN Large Hadron Collider where high radiation levels will cause significant bulk damage. In addition to increased leakage current and charge collection losses worsening the signal to noise, the induced radiation damage changes the effective doping concentration and represents the limiting factor to long term operation of silicon detectors. The objectives are to develop radiation hard silicon detectors that can operate beyond the limits of the present devices and that ensure guaranteed operation for the whole lifetime of the LHC experimental programme. Radiation induced defect modelling and experimental results show that the silicon radiation hardness depends on the atomic impurities present in the initial monocrystalline material.\\\\ \\\\ Float zone (FZ) silicon materials with addition of oxygen, carbon, nitrogen, germanium and tin were produced as well as epitaxial silicon materials with epilayers up to 200 $\\mu$m thickness. Their im...

  18. Near-infrared emission from mesoporous crystalline germanium

    Energy Technology Data Exchange (ETDEWEB)

    Boucherif, Abderraouf; Aimez, Vincent; Arès, Richard, E-mail: richard.ares@usherbrooke.ca [Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, J1K OA5, Québec (Canada); Laboratoire Nanotechnologies Nanosystèmes (LN2)-CNRS UMI-3463, Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, J1K OA5, Québec (Canada); Korinek, Andreas [Canadian Centre for Electron Microscopy, Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada)

    2014-10-15

    Mesoporous crystalline germanium was fabricated by bipolar electrochemical etching of Ge wafer in HF-based electrolyte. It yields uniform mesoporous germanium layers composed of high density of crystallites with an average size 5-7 nm. Subsequent extended chemical etching allows tuning of crystallites size while preserving the same chemical composition. This highly controllable nanostructure exhibits photoluminescence emission above the bulk Ge bandgap, in the near-infrared range (1095-1360nm) with strong evidence of quantum confinement within the crystallites.

  19. A small diameter, flexible, all attitude, self-contained germanium spectrometer. Operator's manual

    International Nuclear Information System (INIS)

    Bordzindki, R.L.; Lepel, E.A.; Reeves, J.H.; Kohli, R.

    1997-05-01

    The end of the Cold War has brought about tremendous changes in the nuclear complex of the Department of Energy. One of the many changes has been the shutdown or decommissioning of many facilities that performed nuclear work. One of the steps in the process of decommissioning a facility involves the decontamination or removal of drain lines or pipes that may have carried radioactive materials at one time. The removal of all these pipes and drain lines to a nuclear disposal facility could be quite costly. It was suggested by Pacific Northwest National Laboratory (PNNL) that a germanium spectrometer could be built that could fit through straight pipes with a diameter as small as 5.08 cm (2 inches) and pass through curved pipes with a diameter as small as 7.6 cm (3 inches) such as that of a 3-inch p-trap in a drain line. The germanium spectrometer could then be used to simultaneously determine all gamma-ray emitting radionuclides in or surrounding the pipe. By showing the absence of any gamma-ray emitting radionuclides, the pipes could then be reused in place or disposed of as non-radioactive material, thus saving significantly in disposal costs. A germanium spectrometer system has been designed by PNNL and fabricated by Princeton Gamma Tech (PGT) that consists of three segments, each 4.84 cm in diameter and about 10 cm in length. Flexible stainless steel bellows were used to connect the segments. Segment 1 is a small liquid nitrogen reservoir. The reservoir is filled with a sponge-like material which enables the detector to be used in any orientation. A Stirling cycle refrigerator is under development which can replace the liquid nitrogen reservoir to provide continuous cooling and operation

  20. Depth of Ultra High Energy Cosmic Ray Induced Air Shower Maxima Measured by the Telescope Array Black Rock and Long Ridge FADC Fluorescence Detectors and Surface Array in Hybrid Mode

    Science.gov (United States)

    Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; di Matteo, A.; Fujii, T.; Fujita, K.; Fukushima, M.; Furlich, G.; Goto, T.; Hanlon, W.; Hayashi, M.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jeong, H. M.; Jeong, S. M.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kishigami, S.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kuznetsov, M.; Kwon, Y. J.; Lee, K. H.; Lubsandorzhiev, B.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuyama, T.; Matthews, J. N.; Mayta, R.; Minamino, M.; Mukai, K.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, R.; Nakamura, T.; Nonaka, T.; Oda, H.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Okuda, T.; Omura, Y.; Ono, M.; Onogi, R.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sahara, R.; Saito, K.; Saito, Y.; Sakaki, N.; Sakurai, N.; Scott, L. M.; Seki, T.; Sekino, K.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takagi, Y.; Takahashi, Y.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Wong, T.; Yamamoto, M.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zhezher, Y.; Zundel, Z.; Telescope Array Collaboration

    2018-05-01

    The Telescope Array (TA) observatory utilizes fluorescence detectors and surface detectors (SDs) to observe air showers produced by ultra high energy cosmic rays in Earth’s atmosphere. Cosmic-ray events observed in this way are termed hybrid data. The depth of air shower maximum is related to the mass of the primary particle that generates the shower. This paper reports on shower maxima data collected over 8.5 yr using the Black Rock Mesa and Long Ridge fluorescence detectors in conjunction with the array of SDs. We compare the means and standard deviations of the observed {X}\\max distributions with Monte Carlo {X}\\max distributions of unmixed protons, helium, nitrogen, and iron, all generated using the QGSJet II-04 hadronic model. We also perform an unbinned maximum likelihood test of the observed data, which is subjected to variable systematic shifting of the data {X}\\max distributions to allow us to test the full distributions, and compare them to the Monte Carlo to see which elements are not compatible with the observed data. For all energy bins, QGSJet II-04 protons are found to be compatible with TA hybrid data at the 95% confidence level after some systematic {X}\\max shifting of the data. Three other QGSJet II-04 elements are found to be compatible using the same test procedure in an energy range limited to the highest energies where data statistics are sparse.

  1. Radiation detectors

    International Nuclear Information System (INIS)

    2013-01-01

    This sixth chapter presents the operational principles of the radiation detectors; detection using photographic emulsions; thermoluminescent detectors; gas detectors; scintillation detectors; liquid scintillation detectors; detectors using semiconductor materials; calibration of detectors; Bragg-Gray theory; measurement chain and uncertainties associated to measurements

  2. Pulse shape analysis and position determination in segmented HPGe detectors: The AGATA detector library

    Energy Technology Data Exchange (ETDEWEB)

    Bruyneel, B. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); Service de Physique Nucleaire, CEA Saclay, Gif-sur-Yvette (France); Birkenbach, B.; Reiter, P. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany)

    2016-03-15

    The AGATA Detector Library (ADL) was developed for the calculation of signals from highly segmented large volume high-purity germanium (HPGe) detectors. ADL basis sets comprise a huge amount of calculated position-dependent detector pulse shapes. A basis set is needed for Pulse Shape Analysis (PSA). By means of PSA the interaction position of a γ -ray inside the active detector volume is determined. Theoretical concepts of the calculations are introduced and cover the relevant aspects of signal formation in HPGe. The approximations and the realization of the computer code with its input parameters are explained in detail. ADL is a versatile and modular computer code; new detectors can be implemented in this library. Measured position resolutions of the AGATA detectors based on ADL are discussed. (orig.)

  3. Electrodeposition of germanium from supercritical fluids.

    Science.gov (United States)

    Ke, Jie; Bartlett, Philip N; Cook, David; Easun, Timothy L; George, Michael W; Levason, William; Reid, Gillian; Smith, David; Su, Wenta; Zhang, Wenjian

    2012-01-28

    Several Ge(II) and Ge(IV) compounds were investigated as possible reagents for the electrodeposition of Ge from liquid CH(3)CN and CH(2)F(2) and supercritical CO(2) containing as a co-solvent CH(3)CN (scCO(2)) and supercritical CH(2)F(2) (scCH(2)F(2)). For Ge(II) reagents the most promising results were obtained using [NBu(n)(4)][GeCl(3)]. However the reproducibility was poor and the reduction currents were significantly less than the estimated mass transport limited values. Deposition of Ge containing films was possible at high cathodic potential from [NBu(n)(4)][GeCl(3)] in liquid CH(3)CN and supercritical CO(2) containing CH(3)CN but in all cases they were heavily contaminated by C, O, F and Cl. Much more promising results were obtained using GeCl(4) in liquid CH(2)F(2) and supercritical CH(2)F(2). In this case the reduction currents were consistent with mass transport limited reduction and bulk electrodeposition produced amorphous films of Ge. Characterisation by XPS showed the presence of low levels of O, F and C, XPS confirmed the presence of Ge together with germanium oxides, and Raman spectroscopy showed that the as deposited amorphous Ge could be crystallised by the laser used in obtaining the Raman measurements.

  4. Tunnel current across linear homocatenated germanium chains

    International Nuclear Information System (INIS)

    Matsuura, Yukihito

    2014-01-01

    The electronic transport properties of germanium oligomers catenating into linear chains (linear Ge chains) have been theoretically studied using first principle methods. The conduction mechanism of a Ge chain sandwiched between gold electrodes was analyzed based on the density of states and the eigenstates of the molecule in a two-probe environment. Like that of silicon chains (Si chains), the highest occupied molecular orbital of Ge chains contains the extended σ-conjugation of Ge 4p orbitals at energy levels close to the Fermi level; this is in contrast to the electronic properties of linear carbon chains. Furthermore, the conductance of a Ge chain is expected to decrease exponentially with molecular length L. The decay constant β, which is defined as e −βL , of a Ge chain is similar to that of a Si chain, whereas the conductance of the Ge chains is higher than that of Si chains even though the Ge–Ge bond length is longer than the Si–Si bond length

  5. The hyperion particle-γ detector array

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.O.; Burke, J.T.; Casperson, R.J.; Ota, S. [Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Fisher, S.; Parker, J. [Science, Technology and Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Beausang, C.W. [Department of Physics, University of Richmond, 28 Westhampton Way, Richmond, VA 23173 (United States); Dag, M. [Cyclotron Institute, Texas A& M University, College Station, TX 77840 (United States); Humby, P. [Department of Physics, University of Richmond, 28 Westhampton Way, Richmond, VA 23173 (United States); Department of Physics, University of Surrey, Surrey GU27XH (United Kingdom); Koglin, J. [Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); McCleskey, E.; McIntosh, A.B.; Saastamoinen, A. [Cyclotron Institute, Texas A& M University, College Station, TX 77840 (United States); Tamashiro, A.S. [Department of Nuclear Science and Engineering, Oregon State University, Corvallis, OR 97331 (United States); Wilson, E. [Department of Physics, University of Richmond, 28 Westhampton Way, Richmond, VA 23173 (United States); Wu, T.C. [Department of Physics and Astronomy, University of Utah, Salt Lake City UT 84112-0830 (United States)

    2017-06-01

    Hyperion is a new high-efficiency charged-particle γ-ray detector array which consists of a segmented silicon telescope for charged-particle detection and up to fourteen high-purity germanium clover detectors for the detection of coincident γ rays. The array will be used in nuclear physics measurements and Stockpile Stewardship studies and replaces the STARLiTeR array. This article discusses the features of the array and presents data collected with the array in the commissioning experiment.

  6. Determination of the Wetting Angle of Germanium and Germanium-Silicon Melts on Different Substrate Materials

    Science.gov (United States)

    Kaiser, Natalie; Croell, Arne; Szofran, F. R.; Cobb. S. D.; Dold, P.; Benz, K. W.

    1999-01-01

    During Bridgman growth of semiconductors detachment of the crystal and the melt meniscus has occasionally been observed, mainly under microgravity (microg) conditions. An important factor for detached growth is the wetting angle of the melt with the crucible material. High contact angles are more likely to result in detachment of the growing crystal from the ampoule wall. In order to achieve detached growth of germanium (Ge) and germanium-silicon (GeSi) crystals under 1g and microg conditions, sessile drop measurements were performed to determine the most suitable ampoule material as well as temperature dependence of the surface tension for GeSi. Sapphire, fused quartz, glassy carbon, graphite, SiC, pyrolytic Boron Nitride (pBN), AIN, and diamond were used as substrates. Furthermore, different cleaning procedures and surface treatments (etching, sandblasting, etc.) of the same substrate material and their effect on the wetting behavior were studied during these experiments. pBN and AIN substrates exhibited the highest contact angles with values around 170 deg.

  7. Monte Carlo modelling of germanium crystals that are tilted and have rounded front edges

    International Nuclear Information System (INIS)

    Gasparro, Joel; Hult, Mikael; Johnston, Peter N.; Tagziria, Hamid

    2008-01-01

    Gamma-ray detection efficiencies and cascade summing effects in germanium detectors are often calculated using Monte Carlo codes based on a computer model of the detection system. Such a model can never fully replicate reality and it is important to understand how various parameters affect the results. This work concentrates on quantifying two issues, namely (i) the effect of having a Ge-crystal that is tilted inside the cryostat and (ii) the effect of having a model of a Ge-crystal with rounded edges (bulletization). The effect of the tilting is very small (in the order of per mille) when the tilting angles are within a realistic range. The effect of the rounded edges is, however, relatively large (5-10% or higher) particularly for gamma-ray energies below 100 keV

  8. Monte Carlo modelling of germanium crystals that are tilted and have rounded front edges

    Energy Technology Data Exchange (ETDEWEB)

    Gasparro, Joel [EC-JRC-IRMM, Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel (Belgium); Hult, Mikael [EC-JRC-IRMM, Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel (Belgium)], E-mail: mikael.hult@ec.europa.eu; Johnston, Peter N. [Applied Physics, Royal Melbourne Institute of Technology, GPO Box 2476V, Melbourne 3001 (Australia); Tagziria, Hamid [EC-JRC-IPSC, Institute for the Protection and the Security of the Citizen, Via E. Fermi 1, I-21020 Ispra (Vatican City State, Holy See,) (Italy)

    2008-09-01

    Gamma-ray detection efficiencies and cascade summing effects in germanium detectors are often calculated using Monte Carlo codes based on a computer model of the detection system. Such a model can never fully replicate reality and it is important to understand how various parameters affect the results. This work concentrates on quantifying two issues, namely (i) the effect of having a Ge-crystal that is tilted inside the cryostat and (ii) the effect of having a model of a Ge-crystal with rounded edges (bulletization). The effect of the tilting is very small (in the order of per mille) when the tilting angles are within a realistic range. The effect of the rounded edges is, however, relatively large (5-10% or higher) particularly for gamma-ray energies below 100 keV.

  9. Reaction studies of hot silicon, germanium and carbon atoms

    International Nuclear Information System (INIS)

    Gaspar, P.P.

    1990-01-01

    The goal of this project was to increase the authors understanding of the interplay between the kinetic and electronic energy of free atoms and their chemical reactivity by answering the following questions: (1) what is the chemistry of high-energy carbon silicon and germanium atoms recoiling from nuclear transformations; (2) how do the reactions of recoiling carbon, silicon and germanium atoms take place - what are the operative reaction mechanisms; (3) how does the reactivity of free carbon, silicon and germanium atoms vary with energy and electronic state, and what are the differences in the chemistry of these three isoelectronic atoms? This research program consisted of a coordinated set of experiments capable of achieving these goals by defining the structures, the kinetic and internal energy, and the charge states of the intermediates formed in the gas-phase reactions of recoiling silicon and germanium atoms with silane, germane, and unsaturated organic molecules, and of recoiling carbon atoms with aromatic molecules. The reactions of high energy silicon, germanium, and carbon atoms created by nuclear recoil were studied with substrates chosen so that their products illuminated the mechanism of the recoil reactions. Information about the energy and electronic state of the recoiling atoms at reaction was obtained from the variation in end product yields and the extent of decomposition and rearrangement of primary products (usually reactive intermediates) as a function of total pressure and the concentration of inert moderator molecules that remove kinetic energy from the recoiling atoms and can induce transitions between electronic spin states. 29 refs

  10. Transport in silicon-germanium heterostructures

    International Nuclear Information System (INIS)

    Chrastina, Daniel

    2001-01-01

    The work presented here describes the electrical characterization of n- and p-type strained silicon-germanium systems. Theories of quantum transport m low magnetic fields at low temperature are discussed m terms of weak-localization: the traditional theory is shown not to account for the dephasing in a 2-dimensional hole gas behaving in a metallic manner and emergent alternative theories, while promising, require refinement. The mobility as a function of sheet density is measured in a p-type pseudomorphic Si 0.5 Ge 0.5 across the temperature range 350mK-282K; it is shown that calculations of the mobility based on semi-classical scattering mechanisms fail below 10K where quantum transport effects become relevant. A room temperature Hall scattering factor has been extracted. A new functional form has been presented to fit the resistivity as a function of temperature, below 20K: traditional theories of screening and weak localization appear not to be applicable. It is also demonstrated that simple protection circuitry is essential if commercial-scale devices are to be meaningfully investigated. Mobility spectrum analysis is performed on an n-type strained-silicon device. Established analysis methods are discussed and a new method is presented based on the Bryan's Algorithm approach to maximum entropy. The breakdown of the QHE is also investigated: the critical current density compares well to that predicted by an existing theory. Finally, devices in which both electron and hole gases can be induced are investigated. However, it is shown that the two cannier species never co-exist. Design rules are presented which may allow more successful structures to be created. Results are presented which demonstrate the success and the utility of implanted contacts which selectively reach different regions of the structure. (author)

  11. Pulse shape discrimination studies of Phase I Ge-detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kirsch, Andrea [MPI fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Collaboration: GERDA-Collaboration

    2013-07-01

    The GERmanium Detector Array experiment aims to search for the neutrinoless double beta decay (0νββ) of {sup 76}Ge by using isotopically enriched germanium crystals as source and detector simultaneously. The bare semiconductor diodes are operated in liquid argon at cryogenic temperatures in an ultra-low background environment. In addition, Gerda applies different active background reduction techniques, one of which is pulse shape discrimination studies of the current Phase I germanium detectors. The analysis of the signal time structure provides an important tool to distinguish single site events (SSE) of the ββ-decay from multi site events (MSE) of common gamma-ray background or surface events. To investigate the correlation between the signal shape and the interaction position, a new, also to the predominantly deployed closed-ended coaxial HPGe detectors applicable analysis technique has been developed. A summary of the used electronic/detector assembly is given and followed by a discussion of the performed classification procedure by means of accurate pulse shape simulations of 0νββ-like signals. Finally, the obtained results are presented along with an evaluation of the relevance for the Gerda experiment.

  12. Silver-compensated germanium center in α-quartz

    International Nuclear Information System (INIS)

    Laman, F.C.; Weil, J.A.

    1977-01-01

    A synthetic germanium-doped crystal of α-quartz was subjected to an electro-diffusion process (ca. 600 V/cm, 625 0 K), in which Ag + ions were introduced along the crystal's optic axis (c). A 9800 MHz electron paramagnetic resonance spectrum at room temperature, taken after room temperature X-irradiation, revealed the presence of a silver-compensated germanium center Asub(Ge-Ag) with large, almost isotropic 107 Ag and 109 Ag hyperfine splittings. Measurement of the spin-Hamiltonian discloses that a suitable model for the observed center utilizes germanium, substituted for silicon, with the accompanying silver interstitial in a nearby c-axis channel, and with electronic structure in which an appreciable admixture Ge 4+ - Ag 0 to Ge 3+ - Ag + exists. Estimates of the unpaired electron orbital are presented. (author)

  13. Modeling of dislocation dynamics in germanium Czochralski growth

    Science.gov (United States)

    Artemyev, V. V.; Smirnov, A. D.; Kalaev, V. V.; Mamedov, V. M.; Sidko, A. P.; Podkopaev, O. I.; Kravtsova, E. D.; Shimansky, A. F.

    2017-06-01

    Obtaining very high-purity germanium crystals with low dislocation density is a practically difficult problem, which requires knowledge and experience in growth processes. Dislocation density is one of the most important parameters defining the quality of germanium crystal. In this paper, we have performed experimental study of dislocation density during 4-in. germanium crystal growth using the Czochralski method and comprehensive unsteady modeling of the same crystal growth processes, taking into account global heat transfer, melt flow and melt/crystal interface shape evolution. Thermal stresses in the crystal and their relaxation with generation of dislocations within the Alexander-Haasen model have been calculated simultaneously with crystallization dynamics. Comparison to experimental data showed reasonable agreement for the temperature, interface shape and dislocation density in the crystal between calculation and experiment.

  14. Analytical product study of germanium-containing medicine by different ICP-MS applications

    NARCIS (Netherlands)

    Krystek, Petra; Ritsema, Rob

    2004-01-01

    For several years organo-germanium containing medicine has been used for special treatments of e.g. cancer and AIDS. The active substances contain germanium as beta-carboxyethylgermanium sesquioxide ((GeCH2CH 2COO-H)2O3/"Ge-132"), spirogermanium, germanium-lactate-citrate or unspecified forms. For

  15. A dual-PIXE tomography setup for reconstruction of Germanium in ICF target

    Science.gov (United States)

    Guo, N.; Lu, H. Y.; Wang, Q.; Meng, J.; Gao, D. Z.; Zhang, Y. J.; Liang, X. X.; Zhang, W.; Li, J.; Ma, X. J.; Shen, H.

    2017-08-01

    Inertial Confinement Fusion (ICF) is one type of fusion energy research which could initiate nuclear fusion reactions through heating and compressing thermonuclear fuel. Compared to a pure plastic target, Germanium doping into the CH ablator layer by Glow Discharge Polymer (GDP) technique can increase the ablation velocity and the standoff distance between the ablation front and laser-deposition region. During target fabrication process, quantitative doping of Ge should be accurately controlled. Particle Induced X-ray Emission Tomography (PIXE-T) can make not only quantification of the concentration, but also reconstruction of the spatial distribution of doped element. The Si (Li) detector for PIXE tomography technique had a disadvantage of low counting rate. To make up this deficiency, another detector of Si (Li) with the same configuration positioned at the opposite side with the same detective angle 135° have been implemented. Simultaneously acquired elemental maps of Ge obtained using two detectors may be different because of the X-ray absorption along the X-ray exit route in the target. In this paper, the X-ray detection efficiency is drastically improved by this dual-PIXE tomography system.

  16. Ultra-Low Noise Germanium Neutrino Detection system (ULGeN).

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera-Palmer, Belkis [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Barton, Paul [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-07-01

    Monitoring nuclear power plant operation by measuring the antineutrino flux has become an active research field for safeguards and non-proliferation. We describe various efforts to demonstrate the feasibility of reactor monitoring based on the detection of the Coherent Neutrino Nucleus Scattering (CNNS) process with High Purity Germanium (HPGe) technology. CNNS detection for reactor antineutrino energies requires lowering the electronic noise in low-capacitance kg-scale HPGe detectors below 100 eV as well as stringent reduction in other particle backgrounds. Existing state- of-the-art detectors are limited to an electronic noise of 95 eV-FWHM. In this work, we employed an ultra-low capacitance point-contact detector with a commercial integrated circuit preamplifier- on-a-chip in an ultra-low vibration mechanically cooled cryostat to achieve an electronic noise of 39 eV-FWHM at 43 K. We also present the results of a background measurement campaign at the Spallation Neutron Source to select the area with sufficient low background to allow a successful first-time measurement of the CNNS process.

  17. Ultra-Low Noise Germanium Neutrino Detection system (ULGeN)

    International Nuclear Information System (INIS)

    Cabrera-Palmer, Belkis; Barton, Paul

    2017-01-01

    Monitoring nuclear power plant operation by measuring the antineutrino flux has become an active research field for safeguards and non-proliferation. We describe various efforts to demonstrate the feasibility of reactor monitoring based on the detection of the Coherent Neutrino Nucleus Scattering (CNNS) process with High Purity Germanium (HPGe) technology. CNNS detection for reactor antineutrino energies requires lowering the electronic noise in low-capacitance kg-scale HPGe detectors below 100 eV as well as stringent reduction in other particle backgrounds. Existing state- of-the-art detectors are limited to an electronic noise of 95 eV-FWHM. In this work, we employed an ultra-low capacitance point-contact detector with a commercial integrated circuit preamplifier- on-a-chip in an ultra-low vibration mechanically cooled cryostat to achieve an electronic noise of 39 eV-FWHM at 43 K. We also present the results of a background measurement campaign at the Spallation Neutron Source to select the area with sufficient low background to allow a successful first-time measurement of the CNNS process.

  18. Niobium nitride Josephson junctions with silicon and germanium barriers

    International Nuclear Information System (INIS)

    Cukauskas, E.J.; Carter, W.L.

    1988-01-01

    Niobium nitride based junctions with silicon, germanium, and composite silicon/germanium barriers were fabricated and characterized for several barrier compositions. The current-voltage characteristics were analyzed at several temperatures using the Simmons model and numerical integration of the WKB approximation for the average barrier height and effective thickness. The zero voltage conductance was measured from 1.5 K to 300 K and compared to the Mott hopping conductivity model and the Stratton tunneling temperature dependence. Conductivity followed Mott conductivity at temperatures above 60 K for junctions with less than 100 angstrom thick barriers

  19. In vitro binding of germanium to proteins of rice shoots

    International Nuclear Information System (INIS)

    Matsumoto, Hideaki; Takahashi, Eiichi

    1976-01-01

    The possibility of in vitro binding between proteins of rice shoots and germanium (Ge) was investigated. The proteins in mixtures of aqueous extracts of rice shoots and radioactive germanium ( 68 GeO 2 ) were fractionated. The binding of radioactivity to the proteins was observed even after 5 successive fractionation steps from the original mixtures. At the final fractionation step using polyacrylamide gel electrophoresis, a constant proportionality between protein concentration and associated radioactivity was found in most samples although not all. These results indicate that the binding of 68 Ge to proteins is not due to the simple adsorption by proteins. (auth.)

  20. Quantitative spectrographic determination of traces of germanium in lignite

    International Nuclear Information System (INIS)

    Martin, M.; Roca, M.

    1972-01-01

    A burning technique in a d.c. arc at 10 amp has been employed. The standards have been prepared from a natural lignite with a low germanium content. In order to enhance sensitivity, AgCl, K 2 SO 4 , CuF 2 , Sb 2 S 3 and Bi 2 S 3 have been tested as sweeping materials. Using 2% CuF 2 a detection limit of 1 ppm germanium is attainable. Bi, Cu, Sb and Sn have been studied as internal standards: the former leads to the, highest precision (1 6%. Results show good agreement with those obtained by the addition method. (Author) 6 refs

  1. The Gerda Phase II detector assembly

    Energy Technology Data Exchange (ETDEWEB)

    Bode, Tobias; Schoenert, Stefan [Physik-Department E15, Technische Universitaet Muenchen (Germany); Schwingenheuer, Bernhard [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Collaboration: GERDA-Collaboration

    2013-07-01

    Phase II of the Gerda (Germanium Detector Array) experiment will continue the search for the neutrinoless double beta decay (0νββ) of {sup 76}Ge. Prerequisites for Phase II are an increased target mass and a reduced background index of < 10 {sup -3} cts/(keV.kg.yr). Major hardware upgrades to achieve these requirements are scheduled for 2013. They include the deployment of a new radio pure low mass detector assembly. The structural properties of available radio-pure materials and reduction of mass necessitate a change of the electrical contacting used to bias and read-out the detectors. The detector assembly design and the favored contacting solution are presented.

  2. Detached Bridgman Growth of Germanium and Germanium-Silicon Alloy Crystals

    Science.gov (United States)

    Szofran, F. R.; Volz, M. P.; Schweizer, M.; Cobb, S. D.; Motakef, S.; Croell, A.; Dold, P.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Earth based experiments on the science of detached crystal growth are being conducted on germanium and germanium-silicon alloys (2 at% Si average composition) in preparation for a series of experiments aboard the International Space Station (ISS). The purpose of the microgravity experiments includes differentiating among proposed mechanisms contributing to detachment, and confirming or refining our understanding of the detachment mechanism. Because large contact angle are critical to detachment, sessile drop measurements were used to determine the contact angles as a function of temperature and composition for a large number of substrates made of potential ampoule materials. Growth experiments have used pyrolytic boron nitride (pBN) and fused silica ampoules with the majority of the detached results occurring predictably in the pBN. The contact angles were 173 deg (Ge) and 165 deg (GeSi) for pBN. For fused silica, the contact angle decreases from 150 deg to an equilibrium value of 117 deg (Ge) or from 129 deg to an equilibrium value of 100 deg (GeSi) over the duration of the experiment. The nature and extent of detachment is determined by using profilometry in conjunction with optical and electron microscopy. The stability of detachment has been analyzed, and an empirical model for the conditions necessary to achieve sufficient stability to maintain detached growth for extended periods has been developed. Results in this presentation will show that we have established the effects on detachment of ampoule material, pressure difference above and below the melt, and silicon concentration; samples that are nearly completely detached can be grown repeatedly in pBN.

  3. Ionization detector

    International Nuclear Information System (INIS)

    Steele, D.S.

    1987-01-01

    An ionization detector having an array of detectors has, for example, grounding pads positioned in the spaces between some detectors (data detectors) and other detectors (reference detectors). The grounding pads are kept at zero electric potential, i.e. grounded. The grounding serves to drain away electrons and thereby prevent an unwanted accumulation of charge in the spaces, and cause the electric field lines to be more perpendicular to the detectors in regions near the grounding pads. Alternatively, no empty space is provided there being additional, grounded, detectors provided between the data and reference detectors. (author)

  4. Design and hybridization of spectrometric amplification line with low background noise; Conception et hybridisation d`une chaine d`amplification spectrometrique a bas bruit de fond

    Energy Technology Data Exchange (ETDEWEB)

    Sun, S

    1992-07-01

    The work of this thesis must be associated with the realization of EUROGAM detector. This device will be composed in a first time of 45 Germanium gamma radiation detectors (each being surrounded with 10 BGO detectors). The purpose of this thesis was the design and the miniaturization of the amplification line which must be associated with each Germanium detector (are also included the circuit of ballistic shortage correction). The design and study of amplifier has been effected with the help of computer-aided design in using SPICE software. The details are explained widely but in another part, the author studies the theoretical interpretation of disturbing phenomena.

  5. Experimental Characterization of Space Charge in IZIP Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Doughty, T; /UC, Berkeley; Pyle, M.; /Stanford U.; Mirabolfathi, N.; Serfass, B.; /UC, Berkeley; Kamaev, O.; /Queen' s U., Kingston; Hertel, S.; Leman, S.W.; /MIT; Brink, P.; /SLAC; Cabrera, B.; /Stanford U.; Sadoulet, B.; /UC, Berkeley

    2012-06-12

    Interleaved ionization electrode geometries offer the possibility of efficient rejection of near-surface events. The CDMS collaboration has recently implemented this interleaved approach for the charge and phonon readout for our germanium detectors. During a recent engineering run, the detectors were found to lose ionization stability quickly. This paper summarizes studies done in order to determine the underlying cause of the instability, as well as possible running modes that maintain stability without unacceptable loss of livetime. Additionally, results are shown for the new version IZIP mask which attempts to improve the overall stability of the detectors.

  6. Direct observations of the vacancy and its annealing in germanium

    DEFF Research Database (Denmark)

    Slotte, J.; Kilpeläinen, S.; Tuomisto, F.

    2011-01-01

    Weakly n-type doped germanium has been irradiated with protons up to a fluence of 3×1014 cm-2 at 35 K and 100 K in a unique experimental setup. Positron annihilation measurements show a defect lifetime component of 272±4 ps at 35 K in in situ positron lifetime measurements after irradiation at 100...

  7. Radiation-enhanced self- and boron diffusion in germanium

    DEFF Research Database (Denmark)

    Schneider, S.; Bracht, H.; Klug, J.N.

    2013-01-01

    We report experiments on proton radiation-enhanced self- and boron (B) diffusion in germanium (Ge) for temperatures between 515 ∘ C and 720 ∘ C. Modeling of the experimental diffusion profiles measured by means of secondary ion mass spectrometry is achieved on the basis of the Frenkel pair reaction...

  8. Synthesis and characterization of germanium monosulphide (GeS)

    Indian Academy of Sciences (India)

    This paper reports the growth of germanium monosulphide (GeS) single crystals by vapour phase technique using different transporting agents. The single crystallinity and composition of the grown crystals have been verified by transmission electron microscopy (TEM) and energy dispersive analysis of X-rays (EDAX) ...

  9. Dislocation multiplication rate in the early stage of germanium plasticity

    Czech Academy of Sciences Publication Activity Database

    Fikar, J.; Dupas, Corinne; Kruml, Tomáš; Jacques, A.; Martin, J. L.

    400-401, - (2005), s. 431-434 ISSN 0921-5093. [Dislocations 2004. La Colle-sur-Loup, 13.09.2004-17.09.2004] Institutional research plan: CEZ:AV0Z2041904 Keywords : dislocation multiplication * germanium * constitutive modelling Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.347, year: 2005

  10. Effect of normal processes on thermal conductivity of germanium ...

    Indian Academy of Sciences (India)

    Abstract. The effect of normal scattering processes is considered to redistribute the phonon momentum in (a) the same phonon branch – KK-S model and (b) between differ- ent phonon branches – KK-H model. Simplified thermal conductivity relations are used to estimate the thermal conductivity of germanium, silicon and ...

  11. Composite germanium monochromators - results for the TriCS

    Energy Technology Data Exchange (ETDEWEB)

    Schefer, J.; Fischer, S.; Boehm, M.; Keller, L.; Horisberger, M.; Medarde, M.; Fischer, P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Composite germanium monochromators are in the beginning of their application in neutron diffraction. We show here the importance of the permanent quality control with neutrons on the example of the 311 wafers which will be used on the single crystal diffractometer TriCS at SINQ. (author) 2 figs., 3 refs.

  12. Silicon detectors

    International Nuclear Information System (INIS)

    Klanner, R.

    1984-08-01

    The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters. (orig.)

  13. Wilcoxon signed-rank-based technique for the pulse-shape analysis of HPGe detectors

    Science.gov (United States)

    Martín, S.; Quintana, B.; Barrientos, D.

    2016-07-01

    The characterization of the electric response of segmented-contact high-purity germanium detectors requires scanning systems capable of accurately associating each pulse with the position of the interaction that generated it. This process requires an algorithm sensitive to changes above the electronic noise in the pulse shapes produced at different positions, depending on the resolution of the Ge crystal. In this work, a pulse-shape comparison technique based on the Wilcoxon signed-rank test has been developed. It provides a method to distinguish pulses coming from different interaction points in the germanium crystal. Therefore, this technique is a necessary step for building a reliable pulse-shape database that can be used later for the determination of the position of interaction for γ-ray tracking spectrometry devices such as AGATA, GRETA or GERDA. The method was validated by comparison with a χ2 test using simulated and experimental pulses corresponding to a Broad Energy germanium detector (BEGe).

  14. Wilcoxon signed-rank-based technique for the pulse-shape analysis of HPGe detectors

    International Nuclear Information System (INIS)

    Martín, S.; Quintana, B.; Barrientos, D.

    2016-01-01

    The characterization of the electric response of segmented-contact high-purity germanium detectors requires scanning systems capable of accurately associating each pulse with the position of the interaction that generated it. This process requires an algorithm sensitive to changes above the electronic noise in the pulse shapes produced at different positions, depending on the resolution of the Ge crystal. In this work, a pulse-shape comparison technique based on the Wilcoxon signed-rank test has been developed. It provides a method to distinguish pulses coming from different interaction points in the germanium crystal. Therefore, this technique is a necessary step for building a reliable pulse-shape database that can be used later for the determination of the position of interaction for γ-ray tracking spectrometry devices such as AGATA, GRETA or GERDA. The method was validated by comparison with a χ"2 test using simulated and experimental pulses corresponding to a Broad Energy germanium detector (BEGe).

  15. Euromet action 428: transfer of ge detectors efficiency calibration from point source geometry to other geometries; Action euromet 428: transfert de l'etalonnage en rendement de detecteurs au germanium pour une source ponctuelle vers d'autres geometries

    Energy Technology Data Exchange (ETDEWEB)

    Lepy, M.Ch

    2000-07-01

    The EUROMET project 428 examines efficiency transfer computation for Ge gamma-ray spectrometers when the efficiency is known for a reference point source geometry in the 60 keV to 2 MeV energy range. For this, different methods are used, such as Monte Carlo simulation or semi-empirical computation. The exercise compares the application of these methods to the same selected experimental cases to determine the usage limitations versus the requested accuracy. For carefully examining these results and trying to derive information for improving the computation codes, this study was limited to a few simple cases, from an experimental efficiency calibration for point source at 10-cm source-to-detector distance. The first part concerns the simplest case of geometry transfer, i.e., using point sources for 3 source-to-detector distances: 2,5 and 20 cm; the second part deals with transfer from point source geometry to cylindrical geometry with three different matrices. The general results show that the deviations between the computed results and the measured efficiencies are for the most part within 10%. The quality of the results is rather inhomogeneous and shows that these codes cannot be used directly for metrological purposes. However, most of them are operational for routine measurements when efficiency uncertainties of 5-10% can be sufficient. (author)

  16. Hybrid XRF

    International Nuclear Information System (INIS)

    Heckel, J.

    2002-01-01

    Full text: In the last 10 years significant innovations of EDXRF, e.g. total reflection XRF or polarized beam XRF, were utilized in different industrial applications. The decrease of background within the spectra was the goal of these developments. Excellent detection limits and sensitivities demonstrate the success of these new techniques. Nevertheless, further improvements are possible by using Si drift detectors. These detectors allow the processing of input count rates up to 10 6 cps in comparison to 10 5 of Si(Li) detectors. New excitation optics are necessary to produce such count rates. One possibility is the use of doubly curved crystals between tube and sample. These crystals enable the reflection of the primary beam within the given solid angle (0.4π) of an end window tube to the sample. Using such brightness optics excellent sensitivities mainly for light elements are achievable. The combination of a BRAGG crystal as a wavelength dispersive component and a solid state detector as an energy dispersive component creates a new technique: hybrid XRF. Copyright (2002) Australian X-ray Analytical Association Inc. Copyright (2002) Australian X-ray Analytical Association Inc

  17. The Majorana Demonstrator: A search for neutrinoless double-beta decay of germanium-76

    Science.gov (United States)

    Elliott, S. R.; Abgrall, N.; Aguayo, E.; Avignone, F. T., III; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Combs, D. C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Esterline, J.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, S.; Martin, R. D.; Mertens, S.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G., II; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Soin, A.; Strain, J.; Suriano, A. M.; Timkin, V.; Tornow, W.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.

    2013-12-01

    The Majorana collaboration is searching for neutrinoless double beta decay using 76Ge, which has been shown to have a number of advantages in terms of sensitivities and backgrounds. The observation of neutrinoless double-beta decay would show that lepton number is violated and that neutrinos are Majorana particles and would simultaneously provide information on neutrino mass. Attaining sensitivities for neutrino masses in the inverted hierarchy region, 15 - 50 meV, will require large, tonne-scale detectors with extremely low backgrounds, at the level of ˜1 count/t-y or lower in the region of the signal. The Majorana collaboration, with funding support from DOE Office of Nuclear Physics and NSF Particle Astrophysics, is constructing the Demonstrator, an array consisting of 40 kg of p-type point-contact high-purity germanium (HPGe) detectors, of which ˜30 kg will be enriched to 87% in 76Ge. The Demonstrator is being constructed in a clean room laboratory facility at the 4850' level (4300 m.w.e.) of the Sanford Underground Research Facility (SURF) in Lead, SD. It utilizes a compact graded shield approach with the inner portion consisting of ultra-clean Cu that is being electroformed and machined underground. The primary aim of the Demonstrator is to show the feasibility of a future tonne-scale measurement in terms of backgrounds and scalability.

  18. Electrically Cooled Germanium System for Measurements of Uranium Enrichments in UF6 Cylinders

    International Nuclear Information System (INIS)

    Dvornyak, P.; Koestlbauer, M.; Lebrun, A.; Murray, M.; Nizhnik, V.; Saidler, C.; Twomey, T.

    2010-01-01

    Measurements of Uranium enrichment in UF6 cylinders is a significant part of the IAEA Safeguards verification activities at enrichment and conversion plants. Nowadays, one of the main tools for verification of Uranium enrichment in UF6 cylinders used by Safeguards inspectors is the gamma spectroscopy system with HPGe detector cooled with liquid nitrogen. Electrically Cooled Germanium System (ECGS) is a new compact and portable high resolution gamma spectrometric system free from liquid nitrogen cooling, which can be used for the same safeguards applications. It consists of the ORTEC Micro-trans-SPEC HPGe Portable Spectrometer, a special tungsten collimator and UF6 enrichment measurement software. The enrichment of uranium is determined by of quantifying the area of the 185.7 keV peak provided that the measurement is performed with a detector viewing an infinite thickness of material. Prior starting the verification of uranium enrichment at the facility, the ECGS has to be calibrated with a sample of known uranium enrichment, material matrix, container wall thickness and container material. Evaluation of the ECGS capabilities was performed by carrying out a field test on actual enrichment verification of uranium in UF6 cylinder or other forms of uranium under infinite thickness conditions. The results of these evaluations allow to say that the use of ECGS will enhance practicality of the enrichment measurements and support unannounced inspection activities at enrichment and conversion plants. (author)

  19. Matching Ge detector element geometry to sample size and shape: One does not fit all exclamation point

    International Nuclear Information System (INIS)

    Keyser, R.M.; Twomey, T.R.; Sangsingkeow, P.

    1998-01-01

    For 25 yr, coaxial germanium detector performance has been specified using the methods and values specified in Ref. 1. These specifications are the full-width at half-maximum (FWHM), FW.1M, FW.02M, peak-to-Compton ratio, and relative efficiency. All of these measurements are made with a 60 Co source 25 cm from the cryostat endcap and centered on the axis of the detector. These measurements are easy to reproduce, both because they are simple to set up and use a common source. These standard tests have been useful in guiding the user to an appropriate detector choice for the intended measurement. Most users of germanium gamma-ray detectors do not make measurements in this simple geometry. Germanium detector manufacturers have worked over the years to make detectors with better resolution, better peak-to-Compton ratios, and higher efficiency--but all based on measurements using the IEEE standard. Advances in germanium crystal growth techniques have made it relatively easy to provide detector elements of different shapes and sizes. Many of these different shapes and sizes can give better results for a specific application than other shapes and sizes. But, the detector specifications must be changed to correspond to the actual application. Both the expected values and the actual parameters to be specified should be changed. In many cases, detection efficiency, peak shape, and minimum detectable limit for a particular detector/sample combination are valuable specifications of detector performance. For other situations, other parameters are important, such as peak shape as a function of count rate. In this work, different sample geometries were considered. The results show the variation in efficiency with energy for all of these sample and detector geometries. The point source at 25 cm from the endcap measurement allows the results to be compared with the currently given IEEE criteria. The best sample/detector configuration for a specific measurement requires more and

  20. GERDA phase II detectors: Behind the production and characterisation at low background conditions

    Energy Technology Data Exchange (ETDEWEB)

    Maneschg, Werner [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Collaboration: GERDA Collaboration; and others

    2013-08-08

    The low background GERmanium Detector Array (GERDA) at Laboratori Nazionali del Gran Sasso (LNGS) is designed to search for the rare neutrinoless double beta decay (0νββ) in {sup 76}Ge. Bare germanium diodes are operated in liquid argon which is used as coolant, as passive and soon active as well shield against external radiation. Currently, Phase I of the experiment is running using ∼15 kg of co-axial High Purity Germanium diodes. In order to increase the sensitivity of the experiment 30 Broad Energy Germanium (BEGe) diodes will be added within 2013. This presentation reviews the production chain of the new BEGe detectors from isotopic enrichment to diode production and testing. As demonstrated all steps were carefully planned in order to minimize the exposure of the enriched germanium to cosmic radiation. Following this premise, acceptance and characterisation measurement of the newly produced diodes have been performed within the HEROICA project in the Belgian underground laboratory HADES close to the diode manufacturer. The test program and the results from a subset of the recently terminated GERDA Phase II BEGe survey will be presented.