Science.gov

Sample records for hpge detector efficiencies

  1. Optimization of geometric parameters for Marinelli beaker to maximize the detection efficiency of an HPGe detector

    NASA Astrophysics Data System (ADS)

    Ahmed, Asm Sabbir; Capello, Kevin; Chiang, Albert; Cardenas-Mendez, Erick; Kramer, Gary H.

    2009-11-01

    This paper describes the optimization of the geometric parameters of a Marinelli beaker to maximize the detection efficiency of sample measurement with a High Purity Germanium (HPGe) detector. A Monte Carlo model was developed and the detector pulse spectrum was studied for different beaker geometries with an HPGe detector. The results show that good sample measurement with an HPGe detector can be obtained by appropriate selection of the sample height over the top of the detector cap and the beaker radius surrounding the detector. Optimum sample heights and beaker radii are recommended for different sample volumes for a given detector specification.

  2. A software for simulation of efficiency of HPGe detectors

    NASA Astrophysics Data System (ADS)

    Khiem, L. H.; Trong, T. D.

    2015-05-01

    Computer software named GE_EFF for calculation of detection efficiency of High Purity Ge detectors recently developed by us is presented. A Monte-Carlo method has been used for simulation. The software has been written in Visual Basic language. The calculated efficiencies for our detectors are in agreement with the measured values using a standard ?-ray sources. The software has been used at our laboratory of Institute of Physics for gamma radiation measurements.

  3. A software package using a mesh-grid method for simulating HPGe detector efficiencies

    SciTech Connect

    Gritzo, Russell E; Jackman, Kevin R; Biegalski, Steven R

    2009-01-01

    Traditional ways of determining the absolute full-energy peak efficiencies of high-purity germanium (HPGe) detectors are often time consuming, cost prohibitive, or not feasible. A software package, KMESS (Kevin's Mesh Efficiency Simulator Software), was developed to assist in predicting these efficiencies. It uses a semiempirical mesh-grid method and works for arbitrary source shapes and counting geometries. The model assumes that any gamma-ray source shape can be treated as a large enough collection of point sources. The code is readily adaptable, has a web-based graphical front-end. and could easily be coupled to a 3D scanner. As will be shown. this software can estimate absolute full-energy peak efficiencies with good accuracy in reasonable computation times. It has applications to the field of gamma-ray spectroscopy because it is a quick and accurate way to assist in performing quantitative analyses using HPGe detectors.

  4. A Software Package Using a Mesh-grid Method for Simulating HPGe Detector Efficiencies

    SciTech Connect

    Kevin Jackman

    2009-10-01

    Traditional ways of determining the absolute full-energy peak efficiencies of high-purity germanium (HPGe) detectors are often time consuming, cost prohibitive, or not feasible. A software package, KMESS (Kevin’s Mesh Efficiency Simulator Software), was developed to assist in predicting these efficiencies. It uses a semiempirical mesh-grid method and works for arbitrary source shapes and counting geometries. The model assumes that any gamma-ray source shape can be treated as a large enough collection of point sources. The code is readily adaptable, has a web-based graphical front-end, and could easily be coupled to a 3D scanner. As will be shown, this software can estimate absolute full-energy peak efficiencies with good accuracy in reasonable computation times. It has applications to the field of gamma-ray spectroscopy because it is a quick and accurate way to assist in performing quantitative analyses using HPGe detectors.

  5. New approach for calibration the efficiency of HpGe detectors

    NASA Astrophysics Data System (ADS)

    Alnour, I. A.; Wagiran, H.; Ibrahim, N.; Hamzah, S.; Siong, W. B.; Elias, M. S.

    2014-02-01

    This work evaluates the efficiency calibrating of HpGe detector coupled with Canberra GC3018 with Genie 2000 software and Ortec GEM25-76-XLB-C with Gamma Vision software; available at Neutron activation analysis laboratory in Malaysian Nuclear Agency (NM). The efficiency calibration curve was constructed from measurement of an IAEA, standard gamma-point sources set composed by 214Am, 57Co, 133Ba, 152Eu, 137Cs and 60Co. The efficiency calibrations were performed for three different geometries: 5, 10 and 15 cm distances from the end cap detector. The polynomial parameters functions were simulated through a computer program, MATLAB in order to find an accurate fit to the experimental data points. The efficiency equation was established from the known fitted parameters which allow for the efficiency evaluation at particular energy of interest. The study shows that significant deviations in the efficiency, depending on the source-detector distance and photon energy.

  6. Evaluation of ANGLE(R), a code for calculating HPGe detector efficiencies

    SciTech Connect

    Homan, Victoria M

    2010-10-25

    This paper evaluates the ANGLE(reg sign) software package, an advanced efficiency calibration software for high purity germanium detectors that is distributed by ORTEC(reg sign). ANGLE(reg sign) uses a semi-empirical approach, by way of the efficiency transfer method, based on the calculated effective solid angle. This approach would have an advantage over the traditional relative and stochastic methods by decreasing the chances for systematic errors and reducing sensitivity to uncertainties in detector parameters. For experimental confirmation, a closed-end coaxial HPGe detector was used with sample geometries frequently encountered at the Los Alamos National Laboratory. The results obtained were sufficient for detector-source configurations which included intercepting layers of plexiglass and carbon graphite, but somewhat insufficient for bare source configurations.

  7. New approach for calibration the efficiency of HpGe detectors

    SciTech Connect

    Alnour, I. A.; Wagiran, H.; Ibrahim, N.; Hamzah, S.; Siong, W. B.; Elias, M. S.

    2014-02-12

    This work evaluates the efficiency calibrating of HpGe detector coupled with Canberra GC3018 with Genie 2000 software and Ortec GEM25-76-XLB-C with Gamma Vision software; available at Neutron activation analysis laboratory in Malaysian Nuclear Agency (NM). The efficiency calibration curve was constructed from measurement of an IAEA, standard gamma–point sources set composed by {sup 214}Am, {sup 57}Co, {sup 133}Ba, {sup 152}Eu, {sup 137}Cs and {sup 60}Co. The efficiency calibrations were performed for three different geometries: 5, 10 and 15 cm distances from the end cap detector. The polynomial parameters functions were simulated through a computer program, MATLAB in order to find an accurate fit to the experimental data points. The efficiency equation was established from the known fitted parameters which allow for the efficiency evaluation at particular energy of interest. The study shows that significant deviations in the efficiency, depending on the source-detector distance and photon energy.

  8. Using lattice tools and unfolding methods for hpge detector efficiency simulation with the Monte Carlo code MCNP5

    NASA Astrophysics Data System (ADS)

    Querol, A.; Gallardo, S.; Ródenas, J.; Verdú, G.

    2015-11-01

    In environmental radioactivity measurements, High Purity Germanium (HPGe) detectors are commonly used due to their excellent resolution. Efficiency calibration of detectors is essential to determine activity of radionuclides. The Monte Carlo method has been proved to be a powerful tool to complement efficiency calculations. In aged detectors, efficiency is partially deteriorated due to the dead layer increasing and consequently, the active volume decreasing. The characterization of the radiation transport in the dead layer is essential for a realistic HPGe simulation. In this work, the MCNP5 code is used to calculate the detector efficiency. The F4MESH tally is used to determine the photon and electron fluence in the dead layer and the active volume. The energy deposited in the Ge has been analyzed using the *F8 tally. The F8 tally is used to obtain spectra and to calculate the detector efficiency. When the photon fluence and the energy deposition in the crystal are known, some unfolding methods can be used to estimate the activity of a given source. In this way, the efficiency is obtained and serves to verify the value obtained by other methods.

  9. Characterization of HPGe detectors using Computed Tomography

    NASA Astrophysics Data System (ADS)

    Hedman, A.; Bahar Gogani, J.; Granström, M.; Johansson, L.; Andersson, J. S.; Ramebäck, H.

    2015-06-01

    Computed Tomography (CT) high-resolution imaging have been used to investigate if there is a significant change in the crystal-to-window distance, i.e. the air gap thickness, in a small n-type detector cooled to 77 K, and in a medium sized p-type HPGe detector when cooled to 100 K. The findings were compared to detector dimension data made available by the manufacturer. The air gap thickness increased by (0.38ą0.07) mm for the n-type detector and by (0.40ą0.15) mm for the p-type detector when the detectors were cooled to 77 resp. 100 K compared to at room temperature. Monte Carlo calculations indicate that these differences have a significant impact on the efficiency in close geometries (<5 cm). In the energy range of 40-700 keV with a source placed directly on endcap, the change in detector efficiency with temperature is 1.9-2.9% for the n-type detector and 0.3-2.1% for the p-type detector. The measured air gap thickness when cooling the detector was 1.1 mm thicker than manufacturer data for the n-type detector and 0.2 mm thicker for the p-type detector. In the energy range of 40-700 keV and with a source on endcap, this result in a change in detector efficiency of 5.2-7.1% for the n-type detector and 0.2-1.0% for the p-type detector, i.e. the detector efficiency is overestimated using data available by the manufacturer.

  10. A method for establishing absolute full-energy peak efficiency and its confidence interval for HPGe detectors

    NASA Astrophysics Data System (ADS)

    Rizwan, U.; Chester, A.; Domingo, T.; Starosta, K.; Williams, J.; Voss, P.

    2015-12-01

    A method is proposed for establishing the absolute efficiency calibration of a HPGe detector including the confidence interval in the energy range of 79.6-3451.2 keV. The calibrations were accomplished with the 133Ba, 60Co, 56Co and 152Eu point-like radioactive sources with only the 60Co source being activity calibrated to an accuracy of 2% at the 90% confidence level. All data sets measured from activity calibrated and uncalibrated sources were fit simultaneously using the linearized least squares method. The proposed fit function accounts for scaling of the data taken with activity uncalibrated sources to the data taken with the high accuracy activity calibrated source. The confidence interval for the fit was found analytically using the covariance matrix. Accuracy of the fit was below 3.5% at the 90% confidence level in the 79.6-3451.2 keV energy range.

  11. A study for improving detection efficiency of an HPGe detector based gamma spectrometer using Monte Carlo simulation and genetic algorithms.

    PubMed

    Huy, Ngo Quang; Binh, Do Quang; An, Vo Xuan

    2012-12-01

    This work aims at improving the detection efficiency of an HPGe detector based gamma spectrometer for measurements of environmental radioactivity sample. Application of a simple genetic algorithm and the Monte Carlo simulation computer code MCNP5 allows to search for optimal dimensions of the Marinelli beaker typed source geometry that maximizes the detector efficiency for a fixed configuration of the gamma spectrometer. The interested gamma energies are in the range of 255-1926 keV. Optimization calculation was repeated several times to deduce average dimensions of an optimal Marinelli beaker typed sample with a volume of 450 cm(3). Effects of gamma energy, sample chemical composition and sample density on the optimal dimensions were also investigated. Calculated results showed that the effects were negligible. A validated experiment with arrangements using an optimal beaker and three other ones was carried out to verify calculated results. It is shown that experimental and calculated results of the detector efficiency are in a good agreement. PMID:23037923

  12. Development of an absolute method for efficiency calibration of a coaxial HPGe detector for large volume sources

    NASA Astrophysics Data System (ADS)

    Ortiz-Ramírez, Pablo C.

    2015-09-01

    In this work an absolute method for the determination of the full energy peak efficiency of a gamma spectroscopy system for voluminous sources is presented. The method was tested for a high-resolution coaxial HPGe detector and cylindrical homogeneous volume source. The volume source is represented by a set of point sources filling its volume. We found that the absolute efficiency of a volume source can be determined as the average over its volume of the absolute efficiency of each point source. Experimentally, we measure the intrinsic efficiency as a function upon source-detector position. Then, considering the solid angle and the attenuations of the gamma rays emitted to the detector by each point source, considered as embedded in the source matrix, the absolute efficiency for each point source inside of the volume was determined. The factor associate with the solid angle and the self-attenuation of photons in the sample was deduced from first principles without any mathematical approximation. The method was tested by determining the specific activity of 137Cs in cylindrical homogeneous sources, using IAEA reference materials with specific activities between 14.2 Bq/kg and 9640 Bq/kg at the moment of the experimentation. The results obtained shown a good agreement with the expected values. The relative difference was less than 7% in most of the cases. The main advantage of this method is that it does not require of the use of expensive and hard to produce standard materials. In addition it does not require of matrix effect corrections, which are the main cause of error in this type of measurements, and it is easy to implement in any nuclear physics laboratory.

  13. Monte Carlo calculations of the HPGe detector efficiency for radioactivity measurement of large volume environmental samples.

    PubMed

    Azbouche, Ahmed; Belgaid, Mohamed; Mazrou, Hakim

    2015-08-01

    A fully detailed Monte Carlo geometrical model of a High Purity Germanium detector with a (152)Eu source, packed in Marinelli beaker, was developed for routine analysis of large volume environmental samples. Then, the model parameters, in particular, the dead layer thickness were adjusted thanks to a specific irradiation configuration together with a fine-tuning procedure. Thereafter, the calculated efficiencies were compared to the measured ones for standard samples containing (152)Eu source filled in both grass and resin matrices packed in Marinelli beaker. From this comparison, a good agreement between experiment and Monte Carlo calculation results was obtained highlighting thereby the consistency of the geometrical computational model proposed in this work. Finally, the computational model was applied successfully to determine the (137)Cs distribution in soil matrix. From this application, instructive results were achieved highlighting, in particular, the erosion and accumulation zone of the studied site. PMID:25982445

  14. Performance of HPGe Detectors in High Magnetic Fields

    E-print Network

    A. Sanchez Lorente; P. Achenbach; M. Agnello; T. Bressani; S. Bufalino; B. Cederwall; A. Feliciello; F. Ferro; J. Gerl; F. Iazzi; M. Kavatsyuk; I. Kojouharov; L. Majling; A. Pantaleo; M. Palomba; J. Pochodzalla; G. Raciti; N. Saito; T. R. Saito; H. Schaffner; C. Sfienti; K. Szymanska; P. -E. Tegnér

    2006-12-18

    A new generation of high-resolution hypernuclear gamma$-spectroscopy experiments with high-purity germanium detectors (HPGe) are presently designed at the FINUDA spectrometer at DAPhiNE, the Frascati phi-factory, and at PANDA, the antiproton proton hadron spectrometer at the future FAIR facility. Both, the FINUDA and PANDA spectrometers are built around the target region covering a large solid angle. To maximise the detection efficiency the HPGe detectors have to be located near the target, and therefore they have to be operated in strong magnetic fields B ~ 1 T. The performance of HPGe detectors in such an environment has not been well investigated so far. In the present work VEGA and EUROBALL Cluster HPGe detectors were tested in the field provided by the ALADiN magnet at GSI. No significant degradation of the energy resolution was found, and a change in the rise time distribution of the pulses from preamplifiers was observed. A correlation between rise time and pulse height was observed and is used to correct the measured energy, recovering the energy resolution almost completely. Moreover, no problems in the electronics due to the magnetic field were observed.

  15. Measurement of ?-decay end point energy with planar HPGe detector

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, T.; Pandit, Deepak; Das, S. K.; Chowdhury, A.; Das, P.; Banerjee, D.; Saha, A.; Mukhopadhyay, S.; Pal, S.; Banerjee, S. R.

    2014-12-01

    The ? - ? coincidence measurement has been performed with a segmented planar Hyper-Pure Germanium (HPGe) detector and a single coaxial HPGe detector to determine the end point energies of nuclear ?-decays. The experimental end point energies have been determined for some of the known ?-decays in 106Rh ?106Pd. The end point energies corresponding to three weak branches in 106Rh ?106Pd decay have been measured for the first time. The ? ray and ? particle responses for the planar HPGe detector were simulated using the Monte Carlo based code GEANT3. The experimentally obtained ? spectra were successfully reproduced with the simulation.

  16. Gamma-ray imaging with coaxial HPGe detector

    SciTech Connect

    Niedermayr, T; Vetter, K; Mihailescu, L; Schmid, G J; Beckedahl, D; Kammeraad, J; Blair, J

    2005-04-12

    We report on the first experimental demonstration of Compton imaging of gamma rays with a single coaxial high-purity germanium (HPGe) detector. This imaging capability is realized by two-dimensional segmentation of the outside contact in combination with digital pulse-shape analysis, which enables to image gamma rays in 4{pi} without employing a collimator. We are able to demonstrate the ability to image the 662keV gamma ray from a {sup 137}Cs source with preliminary event selection with an angular accuracy of 5 degree with an relative efficiency of 0.2%. In addition to the 4{pi} imaging capability, such a system is characterized by its excellent energy resolution and can be implemented in any size possible for Ge detectors to achieve high efficiency.

  17. Initial Field Measurements with the Multisensor Airborne Radiation Survey (MARS) High Purity Germanium (HPGe) Detector Array

    SciTech Connect

    Fast, James E.; Bonebrake, Christopher A.; Dorow, Kevin E.; Glasgow, Brian D.; Jensen, Jeffrey L.; Morris, Scott J.; Orrell, John L.; Pitts, W. Karl; Rohrer, John S.; Todd, Lindsay C.

    2010-06-29

    Abstract: The Multi-sensor Airborne Radiation Survey (MARS) project has developed a new single cryostat detector array design for high purity germanium (HPGe) gamma ray spectrometers that achieves the high detection efficiency required for stand-off detection and actionable characterization of radiological threats. This approach is necessary since a high efficiency HPGe detector can only be built as an array due to limitations in growing large germanium crystals. The system is ruggedized and shock mounted for use in a variety of field applications. This paper reports on results from initial field measurements conducted in a truck and on two different boats.

  18. Application of PHOTON simulation software on calibration of HPGe detectors

    NASA Astrophysics Data System (ADS)

    Nikolic, J.; Puzovic, J.; Todorovic, D.; Rajacic, M.

    2015-11-01

    One of the major difficulties in gamma spectrometry of voluminous environmental samples is the efficiency calibration of the detectors used for the measurement. The direct measurement of different calibration sources, containing isolated ?-ray emitters within the energy range of interest, and subsequent fitting to a parametric function, is the most accurate and at the same time most complicated and time consuming method of efficiency calibration. Many other methods are developed in time, some of them using Monte Carlo simulation. One of such methods is a dedicated and user-friendly program PHOTON, developed to simulate the passage of photons through different media with different geometries. This program was used for efficiency calibration of three HPGe detectors, readily used in Laboratory for Environment and Radiation Protection of the Institute for Nuclear Sciences Vinca, Belgrade, Serbia. The simulation produced the spectral response of the detectors for fixed energy and for different sample geometries and matrices. Thus obtained efficiencies were compared to the values obtained by the measurement of the secondary reference materials and to the results obtained by GEANT4 simulation, in order to establish whether the simulated values agree with the experimental ones. To further analyze the results, a realistic measurement of the materials provided by the IAEA within different interlaboratory proficiency tests, was performed. The activities obtained using simulated efficiencies were compared to the reference values provided by the organizer. A good agreement in the mid energy section of the spectrum was obtained, while for low energies the lack of some parameters in the simulation libraries proved to produce unacceptable discrepancies.

  19. Support of low-level instrument background for HPGe detectors

    SciTech Connect

    Sokolov, A. D.; Starostin, A. S.; Kuzmenko, V. I.; Rozite, A. R.

    2011-07-01

    The development results for the cryostats with the low-level of instrument background supported by special design, the reduction of mass of the materials surrounding detector and application of the materials with very low content of radiation impurities are presented. The development results for HPGe detector with ultra low-level of instrument background for gamma spectrometer under the GEMMA project for investigation of the neutrino magnetic moment are presented. (authors)

  20. Performance revaluation of a N-type coaxial HPGe detector with front edges crystal using MCNPX.

    PubMed

    Azli, Tarek; Chaoui, Zine-El-Abidine

    2015-03-01

    The MCNPX code was used to determine the efficiency of a N-type HPGe detector after two decades of operation. Accounting for the roundedness of the crystal`s front edges and an inhomogeneous description of the detector's dead layers were shown to achieve better agreement between measurements and simulation efficiency determination. The calculations were experimentally verified using point sources in the energy range from 50keV to 1400keV, and an overall uncertainty less than 2% was achieved. In order to use the detector for different matrices and geometries in radioactivity, the suggested model was validated by changing the counting geometry and by using multi-gamma disc sources. The introduced simulation approach permitted the revaluation of the performance of an HPGe detector in comparison of its initial condition, which is a useful tool for precise determination of the thickness of the inhomogeneous dead layer. PMID:25569199

  1. Development of the MCNPX model for the portable HPGe detector

    NASA Astrophysics Data System (ADS)

    Koleska, Michal; Viererbl, Ladislav; Marek, Milan

    2014-11-01

    The portable HPGe coaxial detector Canberra Big MAC is used in LVR-15 research reactor for spectrometric measurement of spent nuclear fuel. The fuel is measured in the dedicated system located in the spent fuel pool situated near the reactor. For the purpose of the spectrometric system calibration, the detector was precisely modeled with the MCNPX code. This model was constructed with the data acquired from the technical specification provided by the manufacturer and from the data obtained by the radiography of the crystal. The detector model was verified on the experimental data measured with available standard radionuclide sources and on-site prepared 110mAg source.

  2. A repair station for HpGe detectors

    NASA Astrophysics Data System (ADS)

    Shearman, Robert; Lister, Christopher; Mitchell, A. J.; Copp, Patrick; Jepeal, Steven; Chowdhury, Partha

    2013-10-01

    Hyper-pure Germanium detectors (HpGe) offer the highest energy resolution for gamma-ray nuclear spectroscopy (about 1.5 keV @ 1 MeV), and are used in all the world's leading detector arrays such as GammaSphere, AGATA and GRETINA. The detector crystals are operated in cryostats at 100 K to reduce thermal noise. To maintain low leakage current and low operating temperatures, cryostat hygiene is very important. Detectors must be regularly maintained by using a high-vacuum, oil-free annealing station. At elevated temperatures above 373 K the process of pumping and baking can also anneal away neutron damage to the detector crystals. This poster will show the design and building of a new HpGe repair station at U. Mass Lowell, and make comparisons of results obtained from this new station to the Gammasphere annealing factory at Argonne. This research is funded by the DOE National Nuclear Safety Administration and the Office of Science.

  3. HPGe detectors for low-temperature nuclear orientation

    NASA Astrophysics Data System (ADS)

    Zákoucký, D.; Srnka, D.; Vénos, D.; Golovko, V.; Kraev, I.; Phalet, T.; Schuurmans, P.; Severijns, N.; Vereecke, B.; Versyck, S.; Nicole; Isolde Collaboration

    2004-03-01

    Using the Low-Temperature Nuclear Orientation (LTNO) technique one can study various interesting properties of atomic nuclei and nuclear decay which can be deduced from the measurements of the angular distributions of charged particles emitted during the decay. However, the use of particle detectors working in conditions of LTNO devices (which are generally not available commercially) is a necessary precondition for the realization of these experiments. Planar HPGe detectors for detection of charged particles at “liquid helium” temperatures were developed and produced at NPI ?ež. Relatively simple technology using vacuum evaporation and diffusion was employed. The performance of detectors at low temperatures was tested and their characteristics measured in a testing cryostat before using them in real experiments. The HPGe detectors were extensively used in a whole range of LTNO experiments with various physical objectives - in offline (IKS Leuven) as well as online (CERN-ISOLDE, Louvain-la-Neuve - LISOL) experiments. In frame of the project “Meson-Exchange Enhancement of First-Forbidden Beta Transitions in the Lead Region”, the measurements of angular distribution of emitted ?-particles allowed to determine experimentally the “meson-exchange currents” contribution to the ?-decay. In the project “Isospin Mixing in N?Z nuclei”, the isospin-forbidden ?-transitions of the nuclei in region (A=50-100) were studied in order to obtain information on the isospin structure of the nuclear states. A new project looking for the possible presence of the tensor currents contribution to the ?-decay is being prepared for the CERN-ISOLDE facility.

  4. Efficiency transfer using the GEANT4 code of CERN for HPGe gamma spectrometry.

    PubMed

    Chagren, S; Tekaya, M Ben; Reguigui, N; Gharbi, F

    2016-01-01

    In this work we apply the GEANT4 code of CERN to calculate the peak efficiency in High Pure Germanium (HPGe) gamma spectrometry using three different procedures. The first is a direct calculation. The second corresponds to the usual case of efficiency transfer between two different configurations at constant emission energy assuming a reference point detection configuration and the third, a new procedure, consists on the transfer of the peak efficiency between two detection configurations emitting the gamma ray in different energies assuming a "virtual" reference point detection configuration. No pre-optimization of the detector geometrical characteristics was performed before the transfer to test the ability of the efficiency transfer to reduce the effect of the ignorance on their real magnitude on the quality of the transferred efficiency. The obtained and measured efficiencies were found in good agreement for the two investigated methods of efficiency transfer. The obtained agreement proves that Monte Carlo method and especially the GEANT4 code constitute an efficient tool to obtain accurate detection efficiency values. The second investigated efficiency transfer procedure is useful to calibrate the HPGe gamma detector for any emission energy value for a voluminous source using one point source detection efficiency emitting in a different energy as a reference efficiency. The calculations preformed in this work were applied to the measurement exercise of the EUROMET428 project. A measurement exercise where an evaluation of the full energy peak efficiencies in the energy range 60-2000keV for a typical coaxial p-type HpGe detector and several types of source configuration: point sources located at various distances from the detector and a cylindrical box containing three matrices was performed. PMID:26623928

  5. FRAM isotopic analysis of uranium in thick-walled containers using high energy gamma rays and planar HPGe detectors.

    SciTech Connect

    Sampson, Thomas E.; Hypes, P. A.; Vo, Duc T.

    2002-01-01

    We describe the use of the Los Alamos FRAM isotopic analysis software to make the first reported measurements on thick-walled UF{sub 6} cylinders using small planar HPGe detectors of the type in common use at the IAEA. Heretofore, planar detector isotopic analysis measurements on uranium have used the 100-keV region and can be defeated by 10 mm of steel absorber. The analysis of planar detector measurements through 13-16 mm of steel shows that FRAM can successfully carry out these measurements and analysis in the 120-1024 keV energy range, a range previously thought to be the sole province of more efficient coaxial detectors. This paper describes the measurement conditions and results and also compares the results to other FRAM measurements with coaxial HPGe detectors. The technique of gamma-ray isotopic analysis of arbitrary samples is desirable for measuring the isotopic composition of uranium in UF{sub 6} cylinders because it does not require calibration with standards or knowledge of the cylinder wall thickness. The International Atomic Energy Agency (IAEA) uses the MGAU (Multi Group Analysis Uranium) uranium isotopic analysis software with planar high purity germanium (HPGe) detectors to measure the isotopic composition of uranium. Measurements on UF{sub 6} cylinders with 13-16-mm thick steel walls are usually unsuccessful because of the strong absorption of the 89-100 keV gamma rays and x-rays that MGAU requires for the measurement. This paper describes the use of the Los Alamos FRAM isotopic analysis software to make these measurements on UF{sub 6} cylinders. Uranium measurements with FRAM typically cover the energy range from 120-1001 keV and can easily be made through the walls of UF{sub 6} cylinders. While these measurements are usually performed with efficient coaxial HPGe detectors, this paper reports the first successful measurements using small planar HPGe detectors of the type in common use at the IAEA.

  6. Phenomenological Model for Predicting the Energy Resolution of Neutron-Damaged Coaxial HPGe Detectors

    SciTech Connect

    C. DeW. Van Siclen; E. H. Seabury; C. J. Wharton; A. J. Caffrey

    2012-10-01

    The peak energy resolution of germanium detectors deteriorates with increasing neutron fluence. This is due to hole capture at neutron-created defects in the crystal which prevents the full energy of the gamma-ray from being recorded by the detector. A phenomenological model of coaxial HPGe detectors is developed that relies on a single, dimensionless parameter that is related to the probability for immediate trapping of a mobile hole in the damaged crystal. As this trap parameter is independent of detector dimensions and type, the model is useful for predicting energy resolution as a function of neutron fluence.

  7. Pulse shape simulation for segmented true-coaxial HPGe detectors

    E-print Network

    I. Abt; A. Caldwell; D. Lenz; J. Liu; X. Liu; B. Majorovits

    2010-04-06

    A new package to simulate the formation of electrical pulses in segmented true-coaxial high purity germanium detectors is presented. The computation of the electric field and weighting potentials inside the detector as well as of the trajectories of the charge carriers is described. In addition, the treatment of bandwidth limitations and noise are discussed. Comparison of simulated to measured pulses, obtained from an 18-fold segmented detector operated inside a cryogenic test facility, are presented.

  8. Comparison of the NDA of HEU Oxide between the AWCC and the HPGe Detector

    SciTech Connect

    Chiang, L. G.; Oberer, R. B.; Gunn, C. A.; Dukes, E. E.; Akin, J. A.

    2009-12-01

    This paper compares the performance of the Active Well Coincidence Counter (AWCC) with the performance of high resolution gamma spectrometry using an HPGe detector to nondestructively assay highly enriched (HEU) oxide. Traditionally the AWCC was considered to be the more appropriate instrument for this measurement. Although the AWCC had a high degree of precision, the HPGe provided the more accurate measurement of this material. The AWCC determines mass of U-235 from the coincident pairs of neutron detections, or doubles rate. The HPGe determines the mass of both U-235 and U238, the enrichment, and the quantity of other radioisotopes. The Tl-208 gamma rays were used to verify the amount of attenuation for the HPGe analysis. Fifty-four cans of enriched U3O8 were shipped to the Y-12 National Security Complex from Los Alamos National Laboratory (LANL) under Scrap Declaration LANL-45. The declared values for net weight, mass of uranium, mass of U-235, and enrichment (percent mass of U-235 to total uranium) are shown in Table A-1. The masses of U-235 range from 104g to 2404g and the enrichment varies from 20% to 98%.

  9. Fabrication and Performance Tests of a Segmented P-Type HPGe Detector

    E-print Network

    George S. King III; Frank T. Avignone III; Christopher E. Cox; Todd W. Hossbach; Wayne Jennings; James H. Reeves

    2007-05-31

    A p-type HPGe detector has been segmented by cutting, with a diamond saw, and etching six circumferential grooves through the Li-diffused dead layer. The degree of segmentation was tested with the 88 keV gamma rays from a well-collimated source of 109Cd. The fraction of events, recognized as occurring in more than one segment, and rejected from the energy interval 2038 +/- 5 keV, was measured as 0.59.

  10. Gamma-ray Full Spectrum Analysis for Environmental Radioactivity by HPGe Detector

    NASA Astrophysics Data System (ADS)

    Jeong, Meeyoung; Lee, Kyeong Beom; Kim, Kyeong Ja; Lee, Min-Kie; Han, Ju-Bong

    2014-12-01

    Odyssey, one of the NASAĄŻs Mars exploration program and SELENE (Kaguya), a Japanese lunar orbiting spacecraft have a payload of Gamma-Ray Spectrometer (GRS) for analyzing radioactive chemical elements of the atmosphere and the surface. In these days, gamma-ray spectroscopy with a High-Purity Germanium (HPGe) detector has been widely used for the activity measurements of natural radionuclides contained in the soil of the Earth. The energy spectra obtained by the HPGe detectors have been generally analyzed by means of the Window Analysis (WA) method. In this method, activity concentrations are determined by using the net counts of energy window around individual peaks. Meanwhile, an alternative method, the so-called Full Spectrum Analysis (FSA) method uses count numbers not only from full-absorption peaks but from the contributions of Compton scattering due to gamma-rays. Consequently, while it takes a substantial time to obtain a statistically significant result in the WA method, the FSA method requires a much shorter time to reach the same level of the statistical significance. This study shows the validation results of FSA method. We have compared the concentration of radioactivity of 40K, 232Th and 238U in the soil measured by the WA method and the FSA method, respectively. The gamma-ray spectrum of reference materials (RGU and RGTh, KCl) and soil samples were measured by the 120% HPGe detector with cosmic muon veto detector. According to the comparison result of activity concentrations between the FSA and the WA, we could conclude that FSA method is validated against the WA method. This study implies that the FSA method can be used in a harsh measurement environment, such as the gamma-ray measurement in the Moon, in which the level of statistical significance is usually required in a much shorter data acquisition time than the WA method.

  11. Matrix formalism and singular-value decomposition for the location of gamma interactions in segmented HPGe detectors

    E-print Network

    P. Desesquelles; T. M. H. Ha; K. Hauschild; A. Korichi; F. Le Blanc; A. Lopez-Martens; A. Olariu; C. M. Petrache

    2009-06-06

    Modern coaxial and planar HPGe detectors allow a precise determination of the energies and trajectories of the impinging gamma-rays. This entails the location of the gamma interactions inside the crystal from the shape of the delivered signals. This paper reviews the state of the art of the analysis of the HPGe response function and proposes methods that lead to optimum signal decomposition. The generic matrix method allows fast location of the interactions even when the induced signals strongly overlap.

  12. Search for double beta decay with HPGe detectors at the Gran Sasso underground laboratory

    NASA Astrophysics Data System (ADS)

    Chkvorets, Oleg

    2008-12-01

    Neutrinoless double-beta decay is practically the only way to establish the Majorana nature of the neutrino mass and its decay rate provides a probe of an effective neutrino mass. Double beta experiments are long-running underground experiments with specific challenges concerning the background reduction and the long term stability. These problems are addressed in this work for the Heidelberg-Moscow (HdM), GENIUS Test Facility (TF) and GERDA experiments. The HdM experiment collected data with enriched 76Ge high purity (HPGe) detectors from 1990 to 2003. An improved analysis of HdM data is presented, exploiting new calibration and spectral shape measurements with the HdM detectors. GENIUS-TF was a test-facility that verified the feasibility of using bare germanium detectors in liquid nitrogen. The first year results of this experiment are discussed. The GERDA experiment has been designed to further increase the sensitivity by operating bare germanium detectors in a high purity cryogenic liquid, which simultaneously serves as a shielding against background and as a cooling media. In the preparatory stage of GERDA, an external background gamma flux measurement was done at the experimental site in the Hall A of the Gran Sasso laboratory. The characterization of the enriched detectors from the HdM and IGEX experiments was performed in the underground detector laboratory for the GERDA collaboration. Long term stability measurements of a bare HPGe detector in liquid argon were carried out. Based on these measurements, the first lower limit on the half-life of neutrinoless double electron capture of 36Ar was established to be 1.85*10^18 years at 68% C.L.

  13. Cosmic-ray-induced background intercomparison with actively shielded HPGe detectors at underground locations

    NASA Astrophysics Data System (ADS)

    Szücs, T.; Bemmerer, D.; Reinhardt, T. P.; Schmidt, K.; Takács, M. P.; Wagner, A.; Wagner, L.; Weinberger, D.; Zuber, K.

    2015-03-01

    The main background above 3MeV for in-beam nuclear astrophysics studies with -ray detectors is caused by cosmic-ray-induced secondaries. The two commonly used suppression methods, active and passive shielding, against this kind of background were formerly considered only as alternatives in nuclear astrophysics experiments. In this work the study of the effects of active shielding against cosmic-ray-induced events at a medium deep location is performed. Background spectra were recorded with two actively shielded HPGe detectors. The experiment was located at 148m below the surface of the Earth in the Reiche Zeche mine in Freiberg, Germany. The results are compared to data with the same detectors at the Earth's surface, and at depths of 45m and 1400m, respectively.

  14. Cosmic-ray induced background intercomparison with actively shielded HPGe detectors at underground locations

    E-print Network

    T. Szücs; D. Bemmerer; T. P. Reinhardt; K. Schmidt; M. P. Takács; A. Wagner; L. Wagner; D. Weinberger; K. Zuber

    2015-03-24

    The main background above 3\\,MeV for in-beam nuclear astrophysics studies with $\\gamma$-ray detectors is caused by cosmic-ray induced secondaries. The two commonly used suppression methods, active and passive shielding, against this kind of background were formerly considered only as alternatives in nuclear astrophysics experiments. In this work the study of the effects of active shielding against cosmic-ray induced events at a medium deep location is performed. Background spectra were recorded with two actively shielded HPGe detectors. The experiment was located at 148\\,m below the surface of the Earth in the Reiche Zeche mine in Freiberg, Germany. The results are compared to data with the same detectors at the Earth's surface, and at depths of 45\\,m and 1400\\,m, respectively.

  15. True coincidence summing corrections for an extended energy range HPGe detector

    NASA Astrophysics Data System (ADS)

    Venegas-Argumedo, Y.; Montero-Cabrera, M. E.

    2015-07-01

    True coincidence summing (TCS) effect for natural radioactive families of U-238 and Th-232 represents a problem when an environmental sample with a close source-detector geometry measurement is performed. By using a certified multi-nuclide standard source to calibrate an energy extended range (XtRa) HPGe detector, it is possible to obtain an intensity spectrum slightly affected by the TCS effect with energies from 46 to 1836 keV. In this work, the equations and some other considerations required to calculate the TCS correction factor for isotopes of natural radioactive chains are described. It is projected a validation of the calibration, performed with the IAEA-CU-2006-03 samples (soil and water).

  16. Field analyses of (238)U and (226)Ra in two uranium mill tailings piles from Niger using portable HPGe detector.

    PubMed

    Déjeant, Adrien; Bourva, Ludovic; Sia, Radia; Galoisy, Laurence; Calas, Georges; Phrommavanh, Vannapha; Descostes, Michael

    2014-11-01

    The radioactivities of (238)U and (226)Ra in mill tailings from the U mines of COMINAK and SOMAĎR in Niger were measured and quantified using a portable High-Purity Germanium (HPGe) detector. The (238)U and (226)Ra activities were measured under field conditions on drilling cores with 600s measurements and without any sample preparation. Field results were compared with those obtained by Inductive Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and emanometry techniques. This comparison indicates that gamma-ray absorption by such geological samples does not cause significant deviations. This work shows the feasibility of using portable HPGe detector in the field as a preliminary method to observe variations of radionuclides concentration with the aim of identifying samples of interest. The HPGe is particularly useful for samples with strong secular disequilibrium such as mill tailings. PMID:25036918

  17. Operation of bare HPGe detectors in LAr/LN2 for the GERDA experiment

    NASA Astrophysics Data System (ADS)

    Barnabé Heider, M.; Cattadori, C.; Chkvorets, O.; di Vacri, A.; Gusev, K.; Schönert, S.; Shirchenko, M.

    2008-11-01

    GERDA is designed to search for 0???-decay of 76Ge using high purity germanium detectors (HPGe), enriched (~ 85%) in 76Ge, directly immersed in LAr which acts both as shield against ? radiation and as cooling medium. The cryostat is located in a stainless steel water tank providing an additional shield against external background. The GERDA experiment aims at a background (b) lessapprox10-3 cts/(kg-y-keV) and energy resolution (FWHM) <= 4 keV at Q?? = 2039 keV. GERDA experiment is foreseen to proceed in two phases. For Phase I, eight reprocessed enriched HPGe detectors from the past HdM [C Balysh et al., Phys. Rev. D 66 (1997) 54] and IGEX [C E Aalseth et al., Phys. of Atomic Nuclei 63 (2000) 1225] experiments (~ 18 kg) and six reprocessed natural HPGe detectors (~ 15 kg) from the Genius Test-Facility [H V Klapdor et al., HIM A 481 (2002) 149] will be deployed in strings. GERDA aims at b lessapprox 10-2 cts/(kgˇkeVˇy). With an exposure of ~ 15 kgˇy of 76Ge and resolution ~ 3.6 keV, the sensitivity on the half-life will be T0?1/2 3 ˇ 1025 y (90 % C.L.) corresponding to mee < 270 meV [V A Rodin et al., Nucl. Phys. A 766 (2006) 107]. In Phase II, new diodes, able to discriminate between single- and multi-site events, will be added (~ 20 kg of 76Ge with intrinsic b ~ 10-2 cts/(kgˇkeVˇy). With an exposure of ~ 120 kgˇy, it is expected T0?1/2 > 1.5 ˇ 1026 y (90% C.L.) corresponding to mee < 110 meV [V A Rodin et al., Nucl. Phys. A 766 (2006) 107]. Three natural p-type HPGe prototypes (different passivation layer designs) are available in the GERDA underground facility at LNGS to investigate the effect of the detector assembly (low-mass low-activity holder), of the handling procedure and of the refurbishment technology on long term stability and spectroscopy performance. The study started on prototype 1 (fully passivated on the borehole side). 60Co ?-irradiation of the detector in LAr resulted in an increase of the leakage current (LC), depending on the rate of LAr ionization which however is reversible. The radiation induced LC is believed to produce pairs of Ar+/e- that are drifted towards the passivation layer by the diode bias electric field (E) dispersed in LAr. In fact, E, numerically calculated by the Maxwell 2D code, resulted strong enough to drift charges before recombination, in the volume surrounding the passivation layer. Charges collected and trapped at the passivation layer cause a decrease of the its resistivity, i.e. an increase of the surface LC. The increase rate depends on the charge collection rate, on the density of trapped charge and on the starting value of the passivation layer resistivity. To study this mechanism two other detector configurations were tested. They have been irradiated in LAr to investigate the influence of both geometry and extension of the passivation layer and measurements with prototype 1 have been also repeated in LN2: prototype 2 (passivation layer only in the groove) shows a ~30 times lower LC increase rate than the case of prototype 1; prototype 3 (no passivation layer) does not show any increase of LC and prototype 1 operated in LN2 does not show any increase. The observed LC is cured by irradiation without HV, explained either by ? ionization of the passivation layer or by effect of the UV LAr scintillation light.

  18. Scoping measurements of radionuclides in L Lake with an underwater HPGe detector

    SciTech Connect

    Dunn, D.L.; Win, W.G.; Bresnahan, P.J.

    1996-06-01

    This study of L Lake was conducted to determine whether the distribution of man-made radiation levels had changed from the time preceding the filling of the newly created lake in 1985. Overflight gamma measurements by EG&G in 1985 mapped the man-made radiation levels, indicating that significant levels were only detected from former stream beds that were to be covered by the lake. the present scoping gamma measurements were consistent with these earlier findings, indicating no major evidence of movement of the radioactivity. These results will be available to guide decisions concerning future plans for the lake. Gamma-emitting radionuclides of L Lake were examined in situ with an underwater HPGe detector and further studied by retrieving various sediment samples for analysis by HPGe gamma spectrometry in the Underground Counting Facility. The predominant man-made radionuclide detected was {sup 137}Cs; it had about 100 times greater activity than {sup 60}Co, which was the only other man-made radionuclide that was detected above trace levels.

  19. Estimation of background spectrum in a shielded HPGe detector using Monte Carlo simulations.

    PubMed

    Medhat, M E; Wang, Yifang

    2014-02-01

    Monte Carlo simulations are powerful tools used to estimate the background ?-radiation detected by high-resolution gamma-ray spectrometry systems with a HPGe (high purity germanium) detector contained inside a lead shield. The purpose of this work was to examine the applicability of Monte Carlo simulations to predict the optimal lead thickness necessary to reduce the background effect in spectrometer measurements. GEANT4 code was applied to simulate the background radiation spectrum at different thicknesses of lead. The simulated results were compared with experimental measurements of background radiation taken at the same shielding thickness. The results show that the background radiation detected depends on the thickness, size and lining of the shield. Simulation showed that 12 cm lead thick is the optimal shielding thickness. PMID:24292007

  20. Evaluation of radioactive background rejection in 76Ge neutrino-lessdouble-beta decay experiments using a highly segmented HPGe detector

    SciTech Connect

    Chan, Yuen-Dat; Campbell, D.B.; Vetter, K.; Henning, R.; Lesko, K.; Chan, Y.D.; Poon, A.W.P.; Perry, M.; Hurley, D.; Smith, A.R.

    2007-02-05

    A highly segmented coaxial HPGe detector was operated in a low background counting facility for over 1 year to experimentally evaluate possible segmentation strategies for the proposed Majorana neutrino-less double-beta decay experiment. Segmentation schemes were evaluated on their ability to reject multi-segment events while retaining single-segment events. To quantify a segmentation scheme's acceptance efficiency the percentage of peak area due to single segment events was calculated for peaks located in the energy region 911-2614 keV. Single interaction site events were represented by the double-escape peak from the 2614 keV decay in {sup 208}Tl located at 1592 keV. In spite of its prototypical nature, the detector performed well under realistic operating conditions and required only minimal human interaction. Though the energy resolution for events with interactions in multiple segments was impacted by inter-segment cross-talk, the implementation of a cross-talk correlation matrix restored acceptable resolution. Additionally, simulations utilizing the MaGe simulation package were performed and found to be in good agreement with experimental observations verifying the external nature of the background radiation.

  1. Double {beta} experiments with the help of scintillation and HPGe detectors at Gran Sasso

    SciTech Connect

    Barabash, A.; Konovalov, S. I.; Umatov, V. I.; Belli, P.; D'Angelo, S.; Di Marco, A.; Bernabei, R.; Boiko, R. S.; Chernyak, D. M.; Danevich, F. A.; Kobychev, V. V.; Kropivyansky, B. N.; Kudovbenko, V. M.; Nagorny, S. S.; Podviyanuk, R. B.; Polischuk, O. G.; Tretyak, V. I.; Vyshnevskyi, I. M.; Yurchenko, S. S.; Brudanin, V. B.; and others

    2011-12-16

    A search for double beta decay of {sup 64,70}Zn, {sup 180,186}W was carried out by using low background ZnWO{sub 4} crystal scintillators, while a CeCl{sub 3} scintillation detector was applied to investigate 2{beta} processes in {sup 136,138,142}Ce. A search for 2{beta} decay of {sup 96,104}Ru, {sup 156,158}Dy, {sup 190,198}Pt and study of 2{nu}2{beta} decay of {sup 100}Mo to the first excited 0{sup +} level of {sup 100}Ru were realized by ultra-low background HPGe {gamma} spectrometry. Moreover, CdWO{sub 4} crystal scintillators from enriched {sup 106}Cd and {sup 116}Cd isotopes were developed to search for 2{beta} decay of {sup 106}Cd and {sup 116}Cd. Finally, experiments aimed to investigate {sup 96,104}Ru and {sup 116}Cd are in progress and a new phase of the experiment to search for 2{beta} processes in {sup 106}Cd is in preparation.

  2. Identification of single events in the HPGe detector: Comparison of various methods based on the analysis of simulated pulse shapes

    E-print Network

    A. M. Bakalyarov; A. Ya. Balysh; S. T. Belyaev; V. I. Lebedev; S. V. Zhukov

    2002-03-12

    Various methods of identification of single events in the HPGe detector are compared on the basis of a program especially designed to simulate pulse shape in a semi-conductor germanium detector. Capabilities of three following methods are shown: (1) an application of the library of single pulse shapes, (2) the single-parameter method, and (3) a separation on the basis of artificial neural networks. The analysis was done in the context of an application of all above-mentioned techniques in the energy interval around the expected neutrino less double beta decay of Ge-76 in the Heidelberg-Moscow experiment.

  3. Low background HPGe spectrometer in investigations of 2? decay

    SciTech Connect

    Rukhadze, Ekaterina [Institute of Experimental and Applied Physics, CTU in Prague, Horska 3a Collaboration: OBELIX Collaboration; TGV Collaboration; SuperNEMO Collaboration; and others

    2013-08-08

    The low background high sensitive HPGe spectrometer called OBELIX is briefly described. The calibration measurements using {sup 152}Eu, {sup 133}Ba and La{sub 2}O{sub 3} sources in different geometries, the obtained efficiency curves for OBELIX HPGe detector, the results of measurements of radioactivity of the NEMO-3 sources ({sup 100}Mo, {sup 150}Nd) as well as future plans for OBELIX detector (e.g. 0?EC/EC decay of {sup 106}Cd) are presented.

  4. Characterization of different surface passivation routes applied to a planar HPGe detector

    NASA Astrophysics Data System (ADS)

    Maggioni, G.; Napoli, D. R.; Eberth, J.; Gelain, M.; Carturan, S.; Grimaldi, M. G.; Tatě, S.

    2015-11-01

    The effects of different passivation methods applied to the same planar high-purity germanium gamma radiation detector have been studied. By means of the scanning with a low-energy collimated gamma source, it has been found that the surface passivation gives rise to a dead layer below the intrinsic Ge surface, whose thickness and distribution are strongly dependent on the passivation type. Measured bulk detector properties like the peak-to-Compton ratio and efficiency have shown a dependence on the passivation and an influence of the passivation type on the depletion voltage, whilst the optimal energy resolution has been the same for all the passivations.

  5. Uncertainty analysis of in-situ gamma spectrometry measurements of air cleaning filter cartridges and 200 L drums by a HPGe detector.

    PubMed

    Slaninka, Alojz; Slávik, Ondrej; Necas, Vladimír

    2010-01-01

    This work deals with most significant sources of uncertainty in determination of radionuclides massic activity in 200 L drums with radioactive waste (RAW) from decommissioning of nuclear power plant (NPP) A1 and operational air cleaning filters coming from different parts of NPP's ventilation system. It turned out that the most significant source of uncertainty is determination of photo peak detection efficiency, in particular measurement geometry. The detection efficiency of HPGe detector has been determined by calculation using ISOCS software (In Situ Object Counting System) and detector characteristics delivered by the manufacturer (LABSOCS). The detector efficiency is influenced by various factors like measurement geometry, deviation from standard geometry, environmental characteristics, sample properties (density, material composition), used collimator etc. Mentioned factors and their contributions to the uncertainty of detection efficiency and thus to the total uncertainty of massic activity determination have been individually evaluated in the paper. The main part of the work consists of evaluation of maximum uncertainty factor due to presence of hypothetical point source in measurement volume for both types of measurement geometry. PMID:19945884

  6. Towards a deep characterization of a 64-fold-pixelated position sensitive detector for a new {gamma}-scanning system of HPGe segmented detectors

    SciTech Connect

    Hernandez-Prieto, A.; Quintana, B.

    2011-07-01

    Characterization of the electrical response of the HPGe segmented detectors is one of the current goals for the Nuclear Physics community in order to perform {gamma}-ray tracking or even imaging with these detectors. For this purpose, scanning devices have to be developed to achieve the signal-position association with the highest precision. In this laboratory, a new scanning system, SALSA (Salamanca Lyso-based Scanning Array), consisting on a high spatial resolution {gamma} camera, is a under development. In this work the whole scanning system is presented and first results for the characterization of the {gamma} camera are shown. (authors)

  7. Response of AGATA Segmented HPGe Detectors to Gamma Rays up to 15.1 MeV

    E-print Network

    F. C. L. Crespi; R. Avigo; F. Camera; S. Akkoyun; A. Atac; D. Bazzacco; M. Bellato; G. Benzoni; N. Blasi; D. Bortolato; S. Bottoni; A. Bracco; S. Brambilla; B. Bruyneel; S. Cerutia; M. Ciemala; S. Coelli; J. Eberth; C. Fanin; E. Farnea; A. Gadea; A. Giaz; A. Gottardo; H. Hess; M. Kmiecik; S. Leoni; A. Maj; D. Mengoni; C. Michelagnoli; B. Million; D. Montanari; L. Pellegri; F. Recchia; P. Reiter; S. Riboldi; C. A. Ur; V. Vandone; J. J. Valiente-Dobon; O. Wieland; A. Wiens; The AGATA Collaboration

    2012-09-06

    The response of AGATA segmented HPGe detectors to gamma rays in the energy range 2-15 MeV was measured. The 15.1 MeV gamma rays were produced using the reaction d(11B,ng)12C at Ebeam = 19.1 MeV, while gamma-rays between 2 to 9 MeV were produced using an Am-Be-Fe radioactive source. The energy resolution and linearity were studied and the energy-to-pulse-height conversion resulted to be linear within 0.05%. Experimental interaction multiplicity distributions are discussed and compared with the results of Geant4 simulations. It is shown that the application of gamma-ray tracking allows a suppression of background radiation following neutron capture by Ge nuclei. Finally the Doppler correction for the 15.1 MeV gamma line, performed using the position information extracted with Pulse-shape Analysis, is discussed.

  8. Signal recognition efficiencies of artificial neural-network pulse-shape discrimination in HPGe -decay searches

    NASA Astrophysics Data System (ADS)

    Caldwell, A.; Cossavella, F.; Majorovits, B.; Palioselitis, D.; Volynets, O.

    2015-07-01

    A pulse-shape discrimination method based on artificial neural networks was applied to pulses simulated for different background, signal and signal-like interactions inside a germanium detector. The simulated pulses were used to investigate variations of efficiencies as a function of used training set. It is verified that neural networks are well-suited to identify background pulses in true-coaxial high-purity germanium detectors. The systematic uncertainty on the signal recognition efficiency derived using signal-like evaluation samples from calibration measurements is estimated to be 5 %. This uncertainty is due to differences between signal and calibration samples.

  9. Reconstruction of a Radiation Point Source's Radial Location Using Goodness-of-Fit Test on Spectra Obtained from an HPGe Detector

    E-print Network

    L. T. Evans; K. Andre; R. De; R. Henning; E. D. Morgan

    2009-08-16

    High purity germanium (HPGe) detectors are ubiquitous in nuclear physics experiments and are also used in numerous low radioactive background detectors. The effect of the position of $^{60}$Co and $^{137}$Cs point sources on the shape of spectra were studied with Monte Carlo and HPGe detector measurements. We briefly confirm previous work on the position dependence of relative heights of peaks. Spectra taken with the radiation sources placed at locations around the detector were then compared using the Kolmogorov-Smirnov (K-S) goodness-of-fit test. We demonstrate that with this method the Compton continuum spectral shape has good sensitivity to the radial location of a point-source, but poor angular resolution. We conclude with a study of the position reconstruction accuracy as a function of the number of counts from the source.

  10. Experimental Determination of the HPGe Spectrometer Efficiency Calibration Curves for Various Sample Geometry for Gamma Energy from 50 keV to 2000 keV

    NASA Astrophysics Data System (ADS)

    Saat, Ahmad; Hamzah, Zaini; Yusop, Mohammad Fariz; Zainal, Muhd Amiruddin

    2010-07-01

    Detection efficiency of a gamma-ray spectrometry system is dependent upon among others, energy, sample and detector geometry, volume and density of the samples. In the present study the efficiency calibration curves of newly acquired (August 2008) HPGe gamma-ray spectrometry system was carried out for four sample container geometries, namely Marinelli beaker, disc, cylindrical beaker and vial, normally used for activity determination of gamma-ray from environmental samples. Calibration standards were prepared by using known amount of analytical grade uranium trioxide ore, homogenized in plain flour into the respective containers. The ore produces gamma-rays of energy ranging from 53 keV to 1001 keV. Analytical grade potassium chloride were prepared to determine detection efficiency of 1460 keV gamma-ray emitted by potassium isotope K-40. Plots of detection efficiency against gamma-ray energy for the four sample geometries were found to fit smoothly to a general form of ? = A?a+B?b, where ? is efficiency, ? is energy in keV, A, B, a and b are constants that are dependent on the sample geometries. All calibration curves showed the presence of a "knee" at about 180 keV. Comparison between the four geometries showed that the efficiency of Marinelli beaker is higher than cylindrical beaker and vial, while cylindrical disk showed the lowest.

  11. Experimental Determination of the HPGe Spectrometer Efficiency Calibration Curves for Various Sample Geometry for Gamma Energy from 50 keV to 2000 keV

    SciTech Connect

    Saat, Ahmad; Hamzah, Zaini; Yusop, Mohammad Fariz; Zainal, Muhd Amiruddin

    2010-07-07

    Detection efficiency of a gamma-ray spectrometry system is dependent upon among others, energy, sample and detector geometry, volume and density of the samples. In the present study the efficiency calibration curves of newly acquired (August 2008) HPGe gamma-ray spectrometry system was carried out for four sample container geometries, namely Marinelli beaker, disc, cylindrical beaker and vial, normally used for activity determination of gamma-ray from environmental samples. Calibration standards were prepared by using known amount of analytical grade uranium trioxide ore, homogenized in plain flour into the respective containers. The ore produces gamma-rays of energy ranging from 53 keV to 1001 keV. Analytical grade potassium chloride were prepared to determine detection efficiency of 1460 keV gamma-ray emitted by potassium isotope K-40. Plots of detection efficiency against gamma-ray energy for the four sample geometries were found to fit smoothly to a general form of {epsilon} = A{Epsilon}{sup a}+B{Epsilon}{sup b}, where {epsilon} is efficiency, {Epsilon} is energy in keV, A, B, a and b are constants that are dependent on the sample geometries. All calibration curves showed the presence of a ''knee'' at about 180 keV. Comparison between the four geometries showed that the efficiency of Marinelli beaker is higher than cylindrical beaker and vial, while cylindrical disk showed the lowest.

  12. A Multi-Contact, Low Capacitance HPGe Detector for High Rate Gamma Spectroscopy

    SciTech Connect

    Cox, Christopher

    2014-12-04

    The detection, identification and non-destructive assay of special nuclear materials and nuclear fission by-products are critically important activities in support of nuclear non-proliferation programs. Both national and international nuclear safeguard agencies recognize that current accounting methods for spent nuclear fuel are inadequate from a safeguards perspective. Radiation detection and analysis by gamma-ray spectroscopy is a key tool in this field, but no instrument exists that can deliver the required performance (energy resolution and detection sensitivity) in the presence of very high background count rates encountered in the nuclear safeguards arena. The work of this project addresses this critical need by developing a unique gamma-ray detector based on high purity germanium that has the previously unachievable property of operating in the 1 million counts-per-second range while achieving state-of-the-art energy resolution necessary to identify and analyze the isotopes of interest. The technical approach was to design and fabricate a germanium detector with multiple segmented electrodes coupled to multi-channel high rate spectroscopy electronics. Dividing the germanium detector’s signal electrode into smaller sections offers two advantages; firstly, the energy resolution of the detector is potentially improved, and secondly, the detector is able to operate at higher count rates. The design challenges included the following; determining the optimum electrode configuration to meet the stringent energy resolution and count rate requirements; determining the electronic noise (and therefore energy resolution) of the completed system after multiple signals are recombined; designing the germanium crystal housing and vacuum cryostat; and customizing electronics to perform the signal recombination function in real time. In this phase I work, commercial off-the-shelf electrostatic modeling software was used to develop the segmented germanium crystal geometry, which underwent several iterations before an optimal electrode configuration was found. The model was tested and validated against real-world measurements with existing germanium detectors. Extensive modeling of electronic noise was conducted using established formulae, and real-world measurements were performed on candidate front-end electronic components. This initial work proved the feasibility of the design with respect to expected high count rate and energy resolution performance. Phase I also delivered the mechanical design of the detector housing and vacuum cryostat to be built in Phase II. Finally, a Monte Carlo simulation was created to show the response of the complete design to a Cs-137 source. This development presents a significant advance for nuclear safeguards instrumentation with increased speed and accuracy of detection and identification of special nuclear materials. Other significant applications are foreseen for a gamma-ray detector that delivers high energy resolution (1keV FWHM noise) at high count rate (1 Mcps), especially in the areas of physics research and materials analysis.

  13. High efficiency photoionization detector

    DOEpatents

    Anderson, David F. (3055 Trinity, Los Alamos, NM 87544)

    1984-01-01

    A high efficiency photoionization detector using tetraaminoethylenes in a gaseous state having a low ionization potential and a relative photoionization cross section which closely matches the emission spectrum of xenon gas. Imaging proportional counters are also disclosed using the novel photoionization detector of the invention. The compound of greatest interest is TMAE which comprises tetrakis(dimethylamino)ethylene which has a measured ionization potential of 5.36.+-.0.02 eV, and a vapor pressure of 0.35 torr at 20.degree. C.

  14. High efficiency photoionization detector

    DOEpatents

    Anderson, D.F.

    1984-01-31

    A high efficiency photoionization detector is described using tetraaminoethylenes in a gaseous state having a low ionization potential and a relative photoionization cross section which closely matches the emission spectrum of xenon gas. Imaging proportional counters are also disclosed using the novel photoionization detector of the invention. The compound of greatest interest is TMAE which comprises tetrakis(dimethylamino)ethylene which has a measured ionization potential of 5.36 [+-] 0.02 eV, and a vapor pressure of 0.35 torr at 20 C. 6 figs.

  15. Gamma-ray multiplicity measurement of the spontaneous fission decay of 252Cf in a segmented HPGe/BGO detector array

    SciTech Connect

    Bleuel, D L; Bernstein, L A; Burke, J T; Gibelin, J; Heffner, M D; Mintz, J; Norman, E B; Phair, L; Scielzo, N D; Sheets, S A; Snyderman, N J; Stoyer, M A; Wiedeking, M

    2008-04-23

    Coincident {gamma} rays from a {sup 252}Cf source were measured using an array of six segmented high-purity germanium (HPGe) Clover detectors each enclosed by 16 bismuth-germanate (BGO) detectors. The detectors were arranged in a cubic pattern around a 1 {micro}Ci {sup 252}Cf source to cover a large solid angle for {gamma}-ray measurement with a reasonable reconstruction of the multiplicity. Neutron multiplicity was determined in certain cases by identifying the prompt {gamma} rays from individual fission fragment pairs. Multiplicity distributions from previous experiments and theoretical models were convolved with the response function of the array and compared to the present results. These results suggest a {gamma}-ray multiplicity spectrum broader than previous measurements and models, and provide no evidence of correlation with neutron multiplicity.

  16. Efficiencies of Quantum Optical Detectors

    E-print Network

    Daniel Hogg; Dominic W. Berry; A. I. Lvovsky

    2014-12-15

    We propose a definition for the efficiency that can be universally applied to all classes of quantum optical detectors. This definition is based on the maximum amount of optical loss that a physically plausible device can experience while still replicating the properties of a given detector. We prove that detector efficiency cannot be increased using linear optical processing. That is, given a set of detectors, as well as arbitrary linear optical elements and ancillary light sources, it is impossible to construct detection devices that would exhibit higher efficiencies than the initial set.

  17. Accurate calculation of well-type detector geometrical efficiency using sources with different shapes and geometries

    NASA Astrophysics Data System (ADS)

    Badawi, M. S.

    2015-10-01

    The well-type detectors are widely used to determine the low level activity in small samples, thus the absolute detector efficiency is required. The calculation of the absolute efficiency of well-type HPGe or NaI(Tl) detectors depends mainly on the value of the geometrical efficiency. The geometrical efficiency depends on the solid angle subtended by various sources situated at different locations from the detector surface. The present work is essentially concerned to introduce a numerical simulation method (NSM) to calculate the geometrical efficiency and give the ability to use it in the theoretical calibration process of ?-ray well-type detectors for using isotropic radiating ?-ray (point, disk or volumetric) sources. The results are compared with some published data to show the approach validity and shows how much this work is important in the efficiency calibration process for the complicated ?-ray detection system.

  18. Signal recognition efficiencies of artificial neural-network pulse-shape discrimination in HPGe $0???$-decay searches

    E-print Network

    A. Caldwell; F. Cossavella; B. Majorovits; D. Palioselitis; O. Volynets

    2015-07-21

    A pulse-shape discrimination method based on artificial neural networks was applied to pulses simulated for different background, signal and signal-like interactions inside a germanium detector. The simulated pulses were used to investigate variations of efficiencies as a function of used training set. It is verified that neural networks are well-suited to identify background pulses in true-coaxial high-purity germanium detectors. The systematic uncertainty on the signal recognition efficiency derived using signal-like evaluation samples from calibration measurements is estimated to be 5\\%. This uncertainty is due to differences between signal and calibration samples.

  19. Study of the real part (f') of anomalous scattering factors for the elements of atomic number from Z = 64 to 73 using HPGe detector

    NASA Astrophysics Data System (ADS)

    Hosur, Savita B.; Naik, L. R.; Badiger, N. M.

    2013-05-01

    The real part ( f') of the anomalous scattering factors for the targets of atomic number ranging from Z = 64 to 73 (Gd, Dy, Yb, Hf and Ta) are determined using low-energy external bremsstrahlung (EB) radiations. In this method, the EB photons are produced by beta particles from a weak beta source of 90Sr - 90Y in a nickel foil. The emitted EB photons are incident on the elemental targets of our study and the transmitted spectrum of the emerging photons from the target is measured using an ORTEC-made High-Purity Germanium (HPGe) detector coupled to an 8 K multichannel analyzer. The transmitted spectra show a sharp decrease in intensity at the K shell binding energies of the target atoms. The regions around the decreased portion have been used to determine the real part of the anomalous scattering factors. The experimentally measured values are found to be in good agreement with the available theoretical values.

  20. Applying a low energy HPGe detector gamma ray spectrometric technique for the evaluation of Pu/Am ratio in biological samples.

    PubMed

    Singh, I S; Mishra, Lokpati; Yadav, J R; Nadar, M Y; Rao, D D; Pradeepkumar, K S

    2015-10-01

    The estimation of Pu/(241)Am ratio in the biological samples is an important input for the assessment of internal dose received by the workers. The radiochemical separation of Pu isotopes and (241)Am in a sample followed by alpha spectrometry is a widely used technique for the determination of Pu/(241)Am ratio. However, this method is time consuming and many times quick estimation is required. In this work, Pu/(241)Am ratio in the biological sample was estimated with HPGe detector based measurements using gamma/X-rays emitted by these radionuclides. These results were compared with those obtained from alpha spectroscopy of sample after radiochemical analysis and found to be in good agreement. PMID:26141295

  1. Tests of HPGe- and scintillation-based backpack ?-radiation survey systems.

    PubMed

    Nilsson, Jonas M C; Östlund, Karl; Söderberg, Joakim; Mattsson, Sören; Rääf, Christopher

    2014-09-01

    The performance of three different backpack-mounted ?-radiation survey systems has been investigated. The systems are based on a LaBr3:Ce detector and a NaI(Tl) detector both with active volume dimensions of 76.2 mm in diameter and 76.2 mm length and a 123% relative efficiency HPGe detector. The detection limits of the systems were tested in a controlled outdoor environment in Sweden, followed by field tests of the HPGe- and LaBr3:Ce-based systems at the site of a radioactive waste repository in Georgia (in the Caucasus region of Eurasia). The results showed that the high efficiency HPGe detector performed significantly better than similar sized LaBr3:Ce and NaI(Tl) detectors, however, the HPGe detector was significantly heavier than the other systems. The use of different analysis methods revealed that creating maps of the survey area was the best method for offline analysis of survey data collected from a large area. Using off-site personnel for analysis of the data proved to be beneficial. PMID:24776755

  2. Experimentally determined vs. Monte Carlo simulated peak-to-valley ratios for a well-characterised n-type HPGe detector.

    PubMed

    Ostlund, Karl; Samuelsson, Christer; Rääf, Christopher L

    2014-10-23

    Measurements and simulations to investigate the contributing factors to the peak-to-valley (PTV) ratio have been both experimentally determined as well as Monte Carlo simulated for a well-characterised HPGe n-type detector together with a Cs-137 gamma source encapsulated in thin polystyrene. Measurements were carried out in a low-background gamma counting facility at Lund University. The results of the PTV ratio have been compared to distinguish what components or variables in the setup that significantly influence the ratio. In addition to manufacture specifications, the detector components have been examined using planar X-ray, source scanning and computer tomography in order to determine and verify component dimensions when necessary. In spite of these efforts a discrepancy of approximately 25% for thin absorbers in the PTV ratio between measurements and calculations is observed. However, this discrepancy becomes less significant for larger absorbing layers of copper (>1mm). This indicates that it would be difficult to achieve a field calibration for in-situ gamma spectrometry using the PTV ratio that could position a Cs-137 source in soil depth shallower than corresponding 1mm layer of copper. The results also showed that when building a detector in simulations part by part, the inner dead layer, and the contact pin are of great importance for the accuracy of the PTV ratio simulations. PMID:25464184

  3. Determination of absolute detection efficiencies for detectors of interest in homeland security

    NASA Astrophysics Data System (ADS)

    Ayaz-Maierhafer, Birsen; DeVol, Timothy A.

    2007-08-01

    The absolute total and absolute peak detection efficiencies of gamma ray detector materials NaI:Tl, CdZnTe, HPGe, HPXe, LaBr 3:Ce and LaCl 3:Ce were simulated and compared to that of polyvinyltoluene (PVT). The dimensions of the PVT detector were 188.82 cm×60.96 cm×5.08 cm, which is a typical size for a single-panel portal monitor. The absolute total and peak detection efficiencies for these detector materials for the point, line and spherical source geometries of 60Co (1332 keV), 137Cs (662 keV) and 241Am (59.5 keV) were simulated at various source-to-detector distances using the Monte Carlo N-Particle software (MCNP5-V1.30). The comparison of the absolute total detection efficiencies for a point, line and spherical source geometry of 60Co and 137Cs at different source-to-detector distance showed that the absolute detection efficiency for PVT is higher relative to the other detectors of typical dimensions for that material. However, the absolute peak detection efficiency of some of these detectors are higher relative to PVT, for example the absolute peak detection efficiency of NaI:Tl (7.62 cm diameter×7.62 cm long), HPGe (7.62 cm diameter×7.62 cm long), HPXe (11.43 cm diameter×60.96 cm long), and LaCl 3:Ce (5.08 cm diameter×5.08 cm long) are all greater than that of a 188.82 cm×60.96 cm×5.08 cm PVT detector for 60Co and 137Cs for all geometries studied. The absolute total and absolute peak detection efficiencies of a right circular cylinder of NaI:Tl with various diameters and thicknesses were determined for a point source. The effect of changing the solid angle on the NaI:Tl detectors showed that with increasing solid angle and detector thickness, the absolute efficiency increases. This work establishes a common basis for differentiating detector materials for passive portal monitoring of gamma ray radiation.

  4. Efficient scalable solid-state neutron detector

    NASA Astrophysics Data System (ADS)

    Moses, Daniel

    2015-06-01

    We report on scalable solid-state neutron detector system that is specifically designed to yield high thermal neutron detection sensitivity. The basic detector unit in this system is made of a 6Li foil coupled to two crystalline silicon diodes. The theoretical intrinsic efficiency of a detector-unit is 23.8% and that of detector element comprising a stack of five detector-units is 60%. Based on the measured performance of this detector-unit, the performance of a detector system comprising a planar array of detector elements, scaled to encompass effective area of 0.43 m2, is estimated to yield the minimum absolute efficiency required of radiological portal monitors used in homeland security.

  5. Efficient scalable solid-state neutron detector.

    PubMed

    Moses, Daniel

    2015-06-01

    We report on scalable solid-state neutron detector system that is specifically designed to yield high thermal neutron detection sensitivity. The basic detector unit in this system is made of a (6)Li foil coupled to two crystalline silicon diodes. The theoretical intrinsic efficiency of a detector-unit is 23.8% and that of detector element comprising a stack of five detector-units is 60%. Based on the measured performance of this detector-unit, the performance of a detector system comprising a planar array of detector elements, scaled to encompass effective area of 0.43 m(2), is estimated to yield the minimum absolute efficiency required of radiological portal monitors used in homeland security. PMID:26133869

  6. DETEFF: An improved Monte Carlo computer program for evaluating the efficiency in coaxial gamma-ray detectors

    NASA Astrophysics Data System (ADS)

    Díaz, N. Cornejo; Vargas, M. Jurado

    2008-02-01

    We present the new improved version of our Monte Carlo program DETEFF for detector efficiency calibration in gamma-ray spectrometry. It can be applied to a wide range of sample geometries commonly used for measurements with coaxial gamma-ray detectors: point, rectangular, disk, cylindrical, and Marinelli sources (the last being newly included in this version). The program is a dedicated code, designed specifically for computation of gamma-ray detector efficiency. Therefore, it is more user-friendly and less time consuming than most multi-purpose programs that are intended for a wide range of applications. The comparison of efficiency values obtained with DETEFF and MCNP4C for a typical HpGe detector and for energies between 40 and 1800 keV for point, cylindrical, and Marinelli geometries gave acceptable results, with relative deviations <2% for most energies. The validity of the program was also tested by comparing the DETEFF-calculated efficiency values with those obtained experimentally using a coaxial HpGe detector for different sources (point, disk, and 250 mL Marinelli beaker) which contain 241Am, 109Cd, 57Co, 139Ce, 85Sr, 137Cs, 88Y, and 60Co. The calculated values were in good agreement with the experimental efficiencies for the three geometries considered, with the relative deviations generally being below 3.0%. These results and those obtained during the application of the previous versions indicate the program's suitability as a tool for the efficiency calibration of coaxial gamma-ray detectors, especially in routine measurements such as environmental monitoring.

  7. Determination of Barium and selected rare-earth elements in geological materials employing a HpGe detector by radioisotope excited x-ray fluorescence

    SciTech Connect

    LaBrecque, J.J.; Preiss, I.L.

    1984-01-01

    The laterite material (geological) from Cerro Impacto was first studied by air radiometric techniques in the 1970's and was found to have an abnormally high radioactive background. Further studies showed this deposit to be rich in thorium, columbium, barium and rare-earth elements (mostly La, Ce, Pr and Nd). A similar work has been reported for the analysis of Brazil's lateritic material from Morro do Ferro to determine elemental compositions (including barium and rare-earth elements) and its relationship to the mobilization of thorium from the deposit using a Co-57 radioisotope source. The objective of this work was to develop an analytical method to determine barium and rare-earth element present in Venezuelan lateritic material from Cerro Impacto. We have employed a method before, employing a Si(Li) detector, but due to the low detection efficiencies in the rare-earth K-lines region (about 30 KeV - 40 KeV), we have decided to study the improvement in sensitivities and detection limits using an hyperpure germanium detector.

  8. Efficient nucleus detector in histopathology images.

    PubMed

    Vink, J P; Van Leeuwen, M B; Van Deurzen, C H M; De Haan, G

    2013-02-01

    In traditional cancer diagnosis, (histo)pathological images of biopsy samples are visually analysed by pathologists. However, this judgment is subjective and leads to variability among pathologists. Digital scanners may enable automated objective assessment, improved quality and reduced throughput time. Nucleus detection is seen as the corner stone for a range of applications in automated assessment of (histo)pathological images. In this paper, we propose an efficient nucleus detector designed with machine learning. We applied colour deconvolution to reconstruct each applied stain. Next, we constructed a large feature set and modified AdaBoost to create two detectors, focused on different characteristics in appearance of nuclei. The proposed modification of AdaBoost enables inclusion of the computational cost of each feature during selection, thus improving the computational efficiency of the resulting detectors. The outputs of the two detectors are merged by a globally optimal active contour algorithm to refine the border of the detected nuclei. With a detection rate of 95% (on average 58 incorrectly found objects per field-of-view) based on 51 field-of-view images of Her2 immunohistochemistry stained breast tissue and a complete analysis in 1 s per field-of-view, our nucleus detector shows good performance and could enable a range of applications in automated assessment of (histo)pathological images. PMID:23252774

  9. Obelix, a new low-background HPGe at Modane Underground Laboratory

    NASA Astrophysics Data System (ADS)

    Loaiza, P.; Brudanin, V.; Piquemal, F.; Rukhadze, E.; Rukhadze, N.; Stekl, I.; Warot, G.; Zampaolo, M.

    2015-08-01

    An ultra-low background coaxial HPGe detector for gamma-ray spectrometry with a relative efficiency of 160%, corresponding to a 600 cm3 Ge crystal, was installed at the Laboratoire Souterrain de Modane, France (4800 m.w.e). To reduce the instrinsic detector background, all parts involved in the detector cryostat were selected for their low radioactivity contamination. A shielding, composed of an inner layer of roman lead and an external layer of regular lead was installed, together with a system to reduce the Rn level inside the sample chamber. The shielding was designed to allow the measurement of Marinelli-shaped samples. We present the constructional details which lead to a remarkable low detector background of 73 cts/kg.d in [40, 3000] keV. Measured samples showed that sensitivities about 100 ?Bq/kg in 226Ra and 228Th are reached for samples of some kg and 30 days of lifetime.

  10. Evaluation of the neutron background in an HPGe target for WIMP direct detection when using a reactor neutrino detector as a neutron veto system

    SciTech Connect

    Ji, Xiangpan; Xu, Ye Lin, Junsong; Feng, Yulong; Li, Haolin

    2013-11-15

    A direct WIMP (weakly interacting massive particle) detector with a neutron veto system is designed to better reject neutrons. The experimental configuration is studied in this paper involves 984 Ge modules placed inside a reactor-neutrino detector. The neutrino detector is used as a neutron veto device. The neutron background for the experimental design is estimated using the Geant4 simulation. The results show that the neutron background can decrease to O(0.01) events per year per tonne of high-purity germanium and it can be ignored in comparison with electron recoils.

  11. Feasibility studies on the burnup measurement of fuel pebbles with HPGe gamma spectrometer

    NASA Astrophysics Data System (ADS)

    Yan, Wei-Hua; Zhang, Li-Guo; Zhang, Zhao; Xiao, Zhi-Gang

    2013-06-01

    The feasibility of utilizing a High Purity Germanium (HPGe) detector for the fuel element burnup measurement in a future Modular Pebble Bed Reactor (MPBR) was studied. First, the HPGe spectrometer was set-up for running the detector at high count rates while keeping the energy resolution adequately high to discriminate the Cs-137 peak from other interfering peaks. Based on these settings, the geometrical conditions are settled. Next, experiments were performed with Co-60 and Cs-137 sources to mimic the counting rates in real applications. With the aid of KORIGEN and MCNP/G4 simulations, it was demonstrated that the uncertainty of the Cs-137 counting rate can be well controlled within 3.5%. Finally, a full size prototype was tested in comparison with detailed Monte Carlo simulation and the efficiency transfer method was further utilized for efficiency calibration. To reduce the uncertainty in the efficiency transfer process, a standard point source embedded in a graphite sphere was used for efficiency calibration. The correction factor due to pebble self-attenuation was carefully studied.

  12. Simulation of background reduction and Compton depression in low-background HPGe spectrometer at a surface laboratory

    E-print Network

    ShunLi Niu; Xiao Cai; ZhenZhong Wu; YuGuang Xie; BoXiang Yu; ZhiGang Wang; Jian Fang; XiLei Sun; LiJun Sun; YingBiao Liu; Long Gao; Xuan Zhang; Hang Zhao; Li Zhou; JunGuang Lv; Tao Hu

    2014-10-16

    High-purity germanium detectors are well suited to analysis the radioactivity of samples. In order to reduce the environmental background, low-activity lead and oxygen free copper are installed outside of the probe to shield gammas, outmost is a plastic scintillator to veto the cosmic rays, and an anti-Compton detector can improve the Peak-to-Compton ratio. Using the GEANT4 tools and taking into account a detailed description of the detector, we optimize the sizes of the detectors to reach the design indexes. A group of experimental data from a HPGe spectrometer in using were used to compare with the simulation. As to new HPGe Detector simulation, considering the different thickness of BGO crystals and anti-coincidence efficiency, the simulation results show that the optimal thickness is 5.5cm, and the Peak-to-Compton ratio of 40K is raised to 1000 when the anti-coincidence efficiency is 0.85. As the background simulation, 15 cm oxygen-free copper plus 10 cm lead can reduce the environmental gamma rays to 0.0024 cps/100 cm3 Ge (50keV~2.8MeV), which is about 10-5 of environmental background.

  13. Development of compact high efficiency microstructured semiconductor neutron detectors

    NASA Astrophysics Data System (ADS)

    McGregor, D. S.; Bellinger, S. L.; Fronk, R. G.; Henson, L.; Huddleston, D.; Ochs, T.; Shultis, J. K.; Sobering, T. J.; Taylor, R. D.

    2015-11-01

    Semiconductor diode detectors coated with neutron reactive materials are generally fashioned as planar diodes coated with 10B, 6LiF, or Gd. Planar detectors coated with 10B or 6LiF are limited to less than 5% intrinsic thermal neutron detection efficiency. Detectors coated with Gd can achieve higher efficiencies, but the low-energy signatures are problematic in the presence of background radiations. Microstructured semiconductor neutron detectors (MSNDs) can now achieve a tenfold increase in neutron detection efficiency over the planar diode designs. These semiconductor neutron detectors are fashioned with a matrix of microstructured patterns etched deeply into the semiconductor substrate and, subsequently, backfilled with neutron reactive materials. Intrinsic thermal-neutron detection efficiencies exceeding 35% have been achieved with devices no thicker than 1 mm while operating on less than 5 V, now allowing for instrumentation to be realized with similar performance as 3He gas-filled detectors.

  14. Efficiency calibration of the 4?--DANCE detector at LANSCE

    NASA Astrophysics Data System (ADS)

    Esch, E.-I.; Haight, R. C.; O'Donnell, J. M.; Reifarth, R.; Bredeweg, T. A.; Rundberg, R. S.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.; Alpizar-Vicente, A. M.; Greife, U.; Hatarik, R.

    2003-10-01

    The DANCE detector is a 4? BaF detector sphere to measure neutron capture cross-sections at the Los Alamos Neutron Science Center (LANSCE). The detector ball is designed to hold 160 BaF crystals. The first assembly of the detector was done with 148 crystals. A series of double coincidence measurements was conducted to determine the gamma-efficiency of the detector ball. Different sources were used for the task. The results of the different measurements will be displayed here.

  15. Using Back-Scattering to Enhance Efficiency in Neutron Detectors

    E-print Network

    Thomas Kittelmann; Esben Klinkby; Xiao Xiao Cai; Kalliopi Kanaki; Carsten P Cooper-Jensen; Richard Hall-Wilton

    2015-09-10

    The principle of using strongly scattering materials to recover efficiency in neutron detectors, via back-scattering of unconverted thermal neutrons, is discussed in general. Feasibility of the method is illustrated through Geant4-based simulations of a specific setup involving a moderator-like material placed behind a single layered boron-10 thin film gaseous detector.

  16. GRABGAM: A Gamma Analysis Code for Ultra-Low-Level HPGe SPECTRA

    SciTech Connect

    Winn, W.G.

    1999-07-28

    The GRABGAM code has been developed for analysis of ultra-low-level HPGe gamma spectra. The code employs three different size filters for the peak search, where the largest filter provides best sensitivity for identifying low-level peaks and the smallest filter has the best resolution for distinguishing peaks within a multiplet. GRABGAM basically generates an integral probability F-function for each singlet or multiplet peak analysis, bypassing the usual peak fitting analysis for a differential f-function probability model. Because F is defined by the peak data, statistical limitations for peak fitting are avoided; however, the F-function does provide generic values for peak centroid, full width at half maximum, and tail that are consistent with a Gaussian formalism. GRABGAM has successfully analyzed over 10,000 customer samples, and it interfaces with a variety of supplementary codes for deriving detector efficiencies, backgrounds, and quality checks.

  17. Absolute efficiency measurements with the 10B based Jalousie detector

    NASA Astrophysics Data System (ADS)

    Modzel, G.; Henske, M.; Houben, A.; Klein, M.; Köhli, M.; Lennert, P.; Meven, M.; Schmidt, C. J.; Schmidt, U.; Schweika, W.

    2014-04-01

    The 10B based Jalousie detector is a replacement for 3He counter tubes, which are nowadays less affordable for large area detectors due to the 3He crisis. In this paper we investigate and verify the performance of the new 10B based detector concept and its adoption for the POWTEX diffractometer, which is designed for the detection of thermal neutrons with predicted detection efficiencies of 75-50% for neutron energies of 10-100 meV, respectively. The predicted detection efficiency has been verified by absolute measurements using neutrons with a wavelength of 1.17 Ĺ (59 meV).

  18. Hit efficiency study of CMS prototype forward pixel detectors

    SciTech Connect

    Kim, Dongwook; /Johns Hopkins U.

    2006-01-01

    In this paper the author describes the measurement of the hit efficiency of a prototype pixel device for the CMS forward pixel detector. These pixel detectors were FM type sensors with PSI46V1 chip readout. The data were taken with the 120 GeV proton beam at Fermilab during the period of December 2004 to February 2005. The detectors proved to be highly efficient (99.27 {+-} 0.02%). The inefficiency was primarily located near the corners of the individual pixels.

  19. Testing the Ge detectors for the MAJORANA DEMONSTRATOR

    SciTech Connect

    Xu, W.; Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Byram, D.; Caldwell, A. S.; Chan, Y. -D.; Christofferson, C. D.; Combs, D. C.; Cuesta, C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; 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, J.; MacMullin, S.; Martin, R. D.; Meijer, S.; Mertens, S.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G.; Poon, A. W.P.; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G.H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Suriano, A. M.; Thompson, J.; Timkin, V.; Tornow, W.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Yakushev, E.; Young, A. R.; Yu, C. -H.; Yumatov, V.

    2015-03-24

    High purity germanium (HPGe) crystals will be used for the MAJORANA DEMONSTRATOR, where they serve as both the source and the detector for neutrinoless double beta decay. It is crucial for the experiment to understand the performance of the HPGe crystals. A variety of crystal properties are being investigated, including basic properties such as energy resolution, efficiency, uniformity, capacitance, leakage current and crystal axis orientation, as well as more sophisticated properties, e.g. pulse shapes and dead layer and transition layer distributions. In this talk, we will present our measurements that characterize the HPGe crystals. We will also discuss the our simulation package for the detector characterization setup, and show that additional information can be extracted from data-simulation comparisons.

  20. Testing the Ge Detectors for the MAJORANA DEMONSTRATOR

    NASA Astrophysics Data System (ADS)

    Xu, W.; Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Combs, D. C.; Cuesta, C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; 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, J.; MacMullin, S.; Martin, R. D.; Meijer, S.; Mertens, S.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G.; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Suriano, A. M.; Thompson, J.; Timkin, V.; Tornow, W.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.

    High purity germanium (HPGe) crystals will be used for the MAJORANA DEMONSTRATOR, where they serve as both the source and the detector for neutrinoless double beta decay. It is crucial for the experiment to understand the performance of the HPGe crystals. A variety of crystal properties are being investigated, including basic properties such as energy resolution, efficiency, uniformity, capacitance, leakage current and crystal axis orientation, as well as more sophisticated properties, e.g. pulse shapes and dead layer and transition layer distributions. In this talk, we will present our measurements that characterize the HPGe crystals. We will also discuss the our simulation package for the detector characterization setup, and show that additional information can be extracted from data-simulation comparisons.

  1. Testing the Ge detectors for the MAJORANA DEMONSTRATOR

    DOE PAGESBeta

    Xu, W.; Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Byram, D.; et al

    2015-03-24

    High purity germanium (HPGe) crystals will be used for the MAJORANA DEMONSTRATOR, where they serve as both the source and the detector for neutrinoless double beta decay. It is crucial for the experiment to understand the performance of the HPGe crystals. A variety of crystal properties are being investigated, including basic properties such as energy resolution, efficiency, uniformity, capacitance, leakage current and crystal axis orientation, as well as more sophisticated properties, e.g. pulse shapes and dead layer and transition layer distributions. In this talk, we will present our measurements that characterize the HPGe crystals. We will also discuss the ourmore ťsimulation package for the detector characterization setup, and show that additional information can be extracted from data-simulation comparisons.Ť less

  2. Random Variation of Detector Efficiency: A Countermeasure against Detector Blinding Attacks for Quantum Key Distribution

    E-print Network

    Charles Ci Wen Lim; Nino Walenta; Matthieu Legre; Nicolas Gisin; Hugo Zbinden

    2015-01-30

    In the recent decade, it has been discovered that QKD systems are extremely vulnerable to side-channel attacks. In particular, by exploiting the internal working knowledge of practical detectors, it is possible to bring them to an operating region whereby only certain target detectors are sensitive to detections. Crucially, the adversary can use this loophole to learn everything about the secret key without introducing any error to the quantum channel. In this work, as a step towards overcoming detector blinding attacks, we focus on an experimentally convenient countermeasure, where the efficiency of the detectors is randomly varied.

  3. Absolute detector quantum-efficiency measurements using correlated photons

    E-print Network

    Migdall, Alan

    metrologia Absolute detector quantum-efficiency measurements using correlated photons A. L. Migdall correlated photons for radiometric purposes has been set up at the National Institute of Standards and Technology (NIST). We use pairs of correlated photons to produce spatial maps of the absolute efficiency

  4. Efficiency and Gamma Sensitivity of a Lithium Glass Neutron Detector

    NASA Astrophysics Data System (ADS)

    Wallace, Adam; Rees, Lawrence; Czirr, Bart; Hoggan, Margarita

    2010-10-01

    Neutron detectors are used in national security applications for detecting potential radioactive material entering the country. Due to the shortage of Helium-3 for neutron detectors, Lithium-6 glass scintillators could be a good material for a replacement detector. Lithium-6 has a large neutron capture cross section, which gives high neutron detection rates. Our detector is based on the fact that neutrons are captured by Lithium-6 which rapidly decays into an alpha particle and triton. Those particles induce scintillation in the glass scintillator and are detected in a photomultiplier tube. The orientation of the plastic and Lithium-6 glass changes the efficiency of the detector. Monte Carlo for Neutral Particles (MCNP) calculations have shown that increasing amounts of plastic provide more efficient neutron detection and that placing a layer of glass in the front of the detector is the ideal configuration. Homeland Security requires that a replacement for Helium-3 detectors must have low gamma sensitivity and high neutron detection efficiency. We are measuring the absolute gamma sensitivity of various arrangements of glass and plastic scintillator. Our goal is to meet the Department of Homeland Security requirement for gamma sensitivity of one part in 10,000.

  5. High efficiency proportional neutron detector with solid liner internal structures

    DOEpatents

    Kisner, Roger Allen; Holcomb, David Eugene; Brown, Gilbert M.

    2014-08-05

    A tube-style neutron detector, a panel-style neutron detector incorporating a plurality of tube-style neutron detectors, and a panel-style neutron detector including a plurality of anode wires are provided. A plurality of channels is provided in a neutron detector such that each channel has an inner surface of a coating layer including a neutron-absorbing material. A wire anode is provided at end of each channel so that electrons generated by a charged daughter particle generated by a neutron are collected to detect a neutron-matter interaction. Moderator units can be incorporated into a neutron detector to provide improved detection efficiencies and/or to determine neutron energy spectrum. Gas-based proportional response from the neutron detectors can be employed for special nuclear material (SNM) detection. This neutron detector can provide similar performance to .sup.3He-based detectors without requiring .sup.3He and without containing toxic, flammable, or high-pressure materials.

  6. Existing NaI detectors; an efficient alternative to He-3 detectors

    NASA Astrophysics Data System (ADS)

    Metwally, Walid A.

    2014-11-01

    Neutron detectors are important in various fields of research, safeguards, security, medicine, and industry. The most common methods for detecting neutrons involve utilization of the 10B(n,?), 6Li(n,?), or 3He(n,p) reactions; with the He-3 filled proportional counters being the most widely used because of their high detection efficiency and good gamma ray discrimination. However these counters have severe drawbacks in terms of detector size and scarcity of He-3. The aim of this work is to investigate an alternative neutron detection method by using a boron lining with existing NaI detectors and compare the results with those obtained from a He-3 detector. The results show a good sensitivity of the boron-lined NaI detector to neutrons at different source locations and a considerable improvement in efficiency compared to He-3 detectors. On top of this the NaI detectors are used to detect the gamma rays from the surrounding source and interacting media.

  7. Improved photon counting efficiency calibration using superconducting single photon detectors

    NASA Astrophysics Data System (ADS)

    Gan, Haiyong; Xu, Nan; Li, Jianwei; Sun, Ruoduan; Feng, Guojin; Wang, Yanfei; Ma, Chong; Lin, Yandong; Zhang, Labao; Kang, Lin; Chen, Jian; Wu, Peiheng

    2015-10-01

    The quantum efficiency of photon counters can be measured with standard uncertainty below 1% level using correlated photon pairs generated through spontaneous parametric down-conversion process. Normally a laser in UV, blue or green wavelength range with sufficient photon energy is applied to produce energy and momentum conserved photon pairs in two channels with desired wavelengths for calibration. One channel is used as the heralding trigger, and the other is used for the calibration of the detector under test. A superconducting nanowire single photon detector with advantages such as high photon counting speed (<20 MHz), low dark count rate (<50 counts per second), and wideband responsivity (UV to near infrared) is used as the trigger detector, enabling correlated photons calibration capabilities into shortwave visible range. For a 355nm single longitudinal mode pump laser, when a superconducting nanowire single photon detector is used as the trigger detector at 1064nm and 1560nm in the near infrared range, the photon counting efficiency calibration capabilities can be realized at 532nm and 460nm. The quantum efficiency measurement on photon counters such as photomultiplier tubes and avalanche photodiodes can be then further extended in a wide wavelength range (e.g. 400-1000nm) using a flat spectral photon flux source to meet the calibration demands in cutting edge low light applications such as time resolved fluorescence and nonlinear optical spectroscopy, super resolution microscopy, deep space observation, and so on.

  8. Resonant infrared detector with substantially unit quantum efficiency

    NASA Technical Reports Server (NTRS)

    Farhoomand, Jam (inventor); Mcmurray, Robert E., Jr. (inventor)

    1994-01-01

    A resonant infrared detector includes an infrared-active layer which has first and second parallel faces and which absorbs radiation of a given wavelength. The detector also includes a first tuned reflective layer, disposed opposite the first face of the infrared-active layer, which reflects a specific portion of the radiation incident thereon and allows a specific portion of the incident radiation at the given wavelength to reach the infrared-active layer. A second reflective layer, disposed opposite the second face of the infrared-active layer, reflects back into the infrared-active layer substantially all of the radiation at the given wavelength which passes through the infrared-active layer. The reflective layers have the effect of increasing the quantum efficiency of the infrared detector relative to the quantum efficiency of the infrared-active layer alone.

  9. Determination of the Quantum Efficiency of a Light Detector

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2008-01-01

    The "quantum efficiency" (QE) is an important property of a light detector. This quantity can be determined in the undergraduate physics laboratory. The experimentally determined QE of a silicon photodiode appeared to be in reasonable agreement with expected values. The experiment confirms the quantum properties of light and seems to be a useful…

  10. High-efficiency neutron detectors and methods of making same

    DOEpatents

    McGregor, Douglas S.; Klann, Raymond

    2007-01-16

    Neutron detectors, advanced detector process techniques and advanced compound film designs have greatly increased neutron-detection efficiency. One embodiment of the detectors utilizes a semiconductor wafer with a matrix of spaced cavities filled with one or more types of neutron reactive material such as 10B or 6LiF. The cavities are etched into both the front and back surfaces of the device such that the cavities from one side surround the cavities from the other side. The cavities may be etched via holes or etched slots or trenches. In another embodiment, the cavities are different-sized and the smaller cavities extend into the wafer from the lower surfaces of the larger cavities. In a third embodiment, multiple layers of different neutron-responsive material are formed on one or more sides of the wafer. The new devices operate at room temperature, are compact, rugged, and reliable in design.

  11. Germanium detectors in homeland security at PNNL

    DOE PAGESBeta

    Stave, S.

    2015-05-01

    Neutron and gamma-ray detection is used for non-proliferation and national security applications. While lower energy resolution detectors such as NaI(Tl) have their place, high purity germanium (HPGe) also has a role to play. A detection with HPGe is often a characterization due to the very high energy resolution. However, HPGe crystals remain small and expensive leaving arrays of smaller crystals as an excellent solution. PNNL has developed two similar HPGe arrays for two very different applications. One array, the Multisensor Aerial Radiation Survey (MARS) detector is a fieldable array that has been tested on trucks, boats, and helicopters. The CASCADESmore ťHPGe array is an array designed to assay samples in a low background environment. The history of HPGe arrays at PNNL and the development of MARS and CASCADES will be detailed in this paper along with some of the other applications of HPGe at PNNL.Ť less

  12. Germanium detectors in homeland security at PNNL

    SciTech Connect

    Stave, S.

    2015-05-01

    Neutron and gamma-ray detection is used for non-proliferation and national security applications. While lower energy resolution detectors such as NaI(Tl) have their place, high purity germanium (HPGe) also has a role to play. A detection with HPGe is often a characterization due to the very high energy resolution. However, HPGe crystals remain small and expensive leaving arrays of smaller crystals as an excellent solution. PNNL has developed two similar HPGe arrays for two very different applications. One array, the Multisensor Aerial Radiation Survey (MARS) detector is a fieldable array that has been tested on trucks, boats, and helicopters. The CASCADES HPGe array is an array designed to assay samples in a low background environment. The history of HPGe arrays at PNNL and the development of MARS and CASCADES will be detailed in this paper along with some of the other applications of HPGe at PNNL.

  13. Germanium Detectors in Homeland Security at PNNL

    SciTech Connect

    Stave, Sean C.

    2015-05-01

    Neutron and gamma-ray detection is used for non-proliferation and national security applications. While lower energy resolution detectors such as NaI(Tl) have their place, high purity germanium (HPGe) also has a role to play. A detection with HPGe is often a characterization due to the very high energy resolution. However, HPGe crystals remain small and expensive leaving arrays of smaller crystals as an excellent solution. PNNL has developed two similar HPGe arrays for two very different applications. One array, the Multisensor Aerial Radiation Survey (MARS) detector is a fieldable array that has been tested on trucks, boats, and helicopters. The CASCADES HPGe array is an array designed to assay samples in a low background environment. The history of HPGe arrays at PNNL and the development of MARS and CASCADES will be detailed in this paper along with some of the other applications of HPGe at PNNL.

  14. Investigation of the quantum efficiency of optical heterodyne detectors

    NASA Technical Reports Server (NTRS)

    Batchman, T. E.

    1984-01-01

    The frequency response and quantum efficiency of optical photodetectors for heterodyne receivers is investigated. The measurements utilized two spectral lines from the output of two lasers as input to the photodetectors. These lines are easily measurable in power and frequency and hence serve as known inputs. By measuring the output current of the photodetector the quantum efficiency is determined as a function of frequency separation between the two input signals. An investigation of the theoretical basis and accuracy of this type of measurement relative to similar measurements utilizing risetime is undertaken. A theoretical study of the heterodyne process in photodetectors based on semiconductor physics is included so that higher bandwidth detectors may be designed. All measurements are made on commercially available detectors and manufacturers' specifications for normal photodetector operation are compared to the measured heterodyne characteristics.

  15. Monte Carlo simulation accuracy for calibrating germanium detector photon efficiency

    SciTech Connect

    Kamboj, Sunita; Kahn, B.

    1997-08-01

    Over the past 30 years, Monte Carlo simulation of photons interacting with matter has gradually improved to the extent that it now appears suitable for calibrating germanium detectors for counting efficiency in gamma-ray spectral analysis. The process is particularly useful because it can be applied for a variety of source shapes and spatial relations between source and detector by simply redefining the geometry, whereas calibration with radioactive standards requires a separate set of measurements for each source shape and location relative to the detector. Simulation accuracy was evaluated for two large (126% and 110%) and one medium-sized (20%) detectors with radioactive point sources at distances of 10 m, 1.6 m, and 0.50 m and with aqueous solutions in a 0.5-L reentrant beaker and in jars of similar volume but various dimensions. The sensitivity in comparing measured and simulated results was limited by a combined uncertainty of about 3% in the radioactive standards and experimental conditions. Simulation was performed with the MCNP-4 code.

  16. Pure sources and efficient detectors for optical quantum information processing

    NASA Astrophysics Data System (ADS)

    Zielnicki, Kevin

    Over the last sixty years, classical information theory has revolutionized the understanding of the nature of information, and how it can be quantified and manipulated. Quantum information processing extends these lessons to quantum systems, where the properties of intrinsic uncertainty and entanglement fundamentally defy classical explanation. This growing field has many potential applications, including computing, cryptography, communication, and metrology. As inherently mobile quantum particles, photons are likely to play an important role in any mature large-scale quantum information processing system. However, the available methods for producing and detecting complex multi-photon states place practical limits on the feasibility of sophisticated optical quantum information processing experiments. In a typical quantum information protocol, a source first produces an interesting or useful quantum state (or set of states), perhaps involving superposition or entanglement. Then, some manipulations are performed on this state, perhaps involving quantum logic gates which further manipulate or entangle the intial state. Finally, the state must be detected, obtaining some desired measurement result, e.g., for secure communication or computationally efficient factoring. The work presented here concerns the first and last stages of this process as they relate to photons: sources and detectors. Our work on sources is based on the need for optimized non-classical states of light delivered at high rates, particularly of single photons in a pure quantum state. We seek to better understand the properties of spontaneous parameteric downconversion (SPDC) sources of photon pairs, and in doing so, produce such an optimized source. We report an SPDC source which produces pure heralded single photons with little or no spectral filtering, allowing a significant rate enhancement. Our work on detectors is based on the need to reliably measure single-photon states. We have focused on optimizing the detection efficiency of visible light photon counters (VLPCs), a single-photon detection technology that is also capable of resolving photon number states. We report a record-breaking quantum efficiency of 91 +/- 3% observed with our detection system. Both sources and detectors are independently interesting physical systems worthy of study, but together they promise to enable entire new classes and applications of information based on quantum mechanics.

  17. On the efficient operation of a CsI-coated GEM photon detector

    E-print Network

    On the efficient operation of a CsI-coated GEM photon detector D. M¨ormann , A. Breskin, R. Chechik Abstract We report on the efficient operation of a CsI-coated GEM photon detector. We describe its. Conditions for obtaining full efficiency of photoelectron extraction and their focusing into the GEM

  18. Position-Dependent Local Detection Efficiency in a Nanowire Superconducting Single-Photon Detector

    E-print Network

    Renema, Jelmer J; Gaudio, Rosalinda; Komen, Irina; Hoog, Koen op 't; Sahin, Dondu; Schilling, Andreas; van Exter, Martin P; Fiore, Andrea; Engel, Andreas; de Dood, Michiel J A

    2015-01-01

    We probe the local detection efficiency in a nanowire superconducting single-photon detector along the cross-section of the wire with a spatial resolution of 10 nm. We experimentally find a strong variation in the local detection efficiency of the device. We demonstrate that this effect explains previously observed variations in NbN detector efficiency as function of device geometry.

  19. DESIGN OF A THERMOSIPHON FOR COOLING LOW-BACKGROUND HPGE ARRAYS

    SciTech Connect

    Aguayo Navarrete, Estanislao; Fast, James E.; Reid, Douglas J.

    2012-11-26

    ABSTRACT A two-phase nitrogen thermosiphon was developed for the new generation of low-background high-purity germanium (HPGe) arrays. The cooling system for these arrays has to be able to handle the heat load (>20 W) presented by a large detector mass while meeting stringent requirements necessary for low-background systems. The HPGe detector modules should operate as close to liquid nitrogen temperature (<80K) as possible to provide adequate operating conditions for a full range of HPGe impurity concentrations. In addition, exceptional temperature stability (<1 K) is needed to reduce electronic gain shifts due to changes in the front-end electronics operating temperature. In order to meet the background requirements of state-of-the-art systems these arrays are enclosed in passive lead and copper shielding up to 1 m thick. In this paper we present a cooling system for low-background experiments that complies with these stringent geometrical restrictions. Active cooling was integrated via a horizontal thermosiphon that can be fabricated using ultra-pure electroformed copper. It was charged with nitrogen to 434 kPa (63 PSIA) at 292 K, which provided a fill ratio of 10%. The results showed that the thermosiphon can effectively remove in excess of 25 W of heat load.

  20. Development of a stochastic detection efficiency calibration procedure for studying collimation effects on a broad energy germanium detector

    NASA Astrophysics Data System (ADS)

    Altavilla, Massimo; Remetti, Romolo

    2013-06-01

    ISPRA, the Italian nuclear safety regulatory body, has started a measurement campaign for validating the performances of in situ gamma-ray spectrometry based on BEGe detectors and ISOCS software. The goal of the validation program is to verify if the mathematical algorithms used by Canberra to account for collimation effects of HpGe detectors continue to work well also for BEGe detectors. This has required the development of a calibration methodology, based on MCNPX code, which, by avoiding any mathematical algorithm utilization, is purely stochastic.Experimental results obtained by such a new procedure, were generally found to be 5% of the reference values. While, in the case of gamma-ray energies greater than 400 keV and small angles collimation, results given by ISOCS software produced larger deviations, around 20%. This work presents a detailed description of the simulation procedure and of the first experimental results.

  1. Determining the absolute efficiency of a delay line microchannel-plate detector using molecular dissociation

    SciTech Connect

    Gaire, B.; Sayler, A. M.; Wang, P. Q.; Johnson, Nora G.; Leonard, M.; Parke, E.; Carnes, K. D.; Ben-Itzhak, I.

    2007-02-15

    We present a method to measure the absolute detection efficiency of a delay-line microchannel-plate detector using the breakup of diatomic molecular ions. This method provides the absolute total detection efficiency, as well as the individual efficiency for each signal of the detector. The method is based on the fact that molecular breakup always yields two hits on the detector, but due to finite detection efficiency some of these events are recorded as single particles while others are detected in pairs. We demonstrate the method by evaluating the detection efficiency for both timing and position signals of a delay-line detector using laser-induced dissociation of molecular ions. In addition, the detection efficiency as a function of position has been determined by dividing the detector into sectors.

  2. Development of A Self Biased High Efficiency Solid-State Neutron Detector for MPACT Applications

    SciTech Connect

    Danon, Yaron; Bhat, Ishwara; Jian-Qiang Lu, James

    2013-09-03

    Neutron detection is an important aspect of materials protection, accounting, and control for transmutation (MPACT). Currently He-3 filled thermal neutron detectors are utilized in many applications; these detectors require high-voltage bias for operation, which complicates the system when multiple detectors are used. In addition, due to recent increase in homeland security activity and the nuclear renaissance, there is a shortage of He-3, and these detectors become more expensive. Instead, cheap solid-state detectors that can be mass produced like any other computer chips will be developed. The new detector does not require a bias for operation, has low gamma sensitivity, and a fast response. The detection system is based on a honeycomb-like silicon device, which is filled with B-10 as the neutron converter; while a silicon p-n diode (i.e., solar cell type device) formed on the thin silicon wall of the honeycomb structure detects the energetic charged particles emitted from the B-10 conversion layer. Such a detector has ~40% calculated thermal neutron detection efficiency with an overall detector thickness of about 200 ?m. Stacking of these devices allows over 90% thermal neutron detection efficiency. The goal of the proposed research is to develop a high-efficiency, low-noise, self-powered solid-state neutron detector system based on the promising results of the existing research program. A prototype of this solid-state neutron detector system with sufficient detector size (up to 8-inch diam., but still portable and inexpensive) and integrated with interface electronics (e.g., preamplifier) will be designed, fabricated, and tested as a coincidence counter for MPACT applications. All fabrications proposed are based on silicon-compatible processing; thus, an extremely cheap detector system could be massively produced like any other silicon chips. Such detectors will revolutionize current neutron detection systems by providing a solid-state alternative to traditional gas-based neutron detectors.

  3. Non-streaming high-efficiency perforated semiconductor neutron detectors, methods of making same and measuring wand and detector modules utilizing same

    DOEpatents

    McGregor, Douglas S. (Riley, KS); Shultis, John K. (Manhattan, KS); Rice, Blake B. (Manhattan, KS); McNeil, Walter J. (Winnfield, KS); Solomon, Clell J. (Wichita, KS); Patterson, Eric L. (Manhattan, KS); Bellinger, Steven L. (Manhattan, KS)

    2010-12-21

    Non-streaming high-efficiency perforated semiconductor neutron detectors, method of making same and measuring wands and detector modules utilizing same are disclosed. The detectors have improved mechanical structure, flattened angular detector responses, and reduced leakage current. A plurality of such detectors can be assembled into imaging arrays, and can be used for neutron radiography, remote neutron sensing, cold neutron imaging, SNM monitoring, and various other applications.

  4. Energy resolution and efficiency of phonon-mediated Kinetic Inductance Detectors for light detection

    E-print Network

    L. Cardani; I. Colantoni; A. Cruciani; S. Di Domizio; M. Vignati; F. Bellini; N. Casali; M. G. Castellano; A. Coppolecchia; C. Cosmelli; C. Tomei

    2015-09-14

    The development of sensitive cryogenic light detectors is of primary interest for bolometric experiments searching for rare events like dark matter interactions or neutrino-less double beta decay. Thanks to their good energy resolution and the natural multiplexed read-out, Kinetic Inductance Detectors (KIDs) are particularly suitable for this purpose. To efficiently couple KIDs-based light detectors to the large crystals used by the most advanced bolometric detectors, active surfaces of several cm$^2$ are needed. For this reason, we are developing phonon-mediated detectors. In this paper we present the results obtained with a prototype consisting of four 40 nm thick aluminum resonators patterned on a 2$\\times$2 cm$^2$ silicon chip, and calibrated with optical pulses and X-rays. The detector features a noise resolution $\\sigma_E=154\\pm7$ eV and an (18$\\pm$2)$\\%$ efficiency.

  5. Energy resolution and efficiency of phonon-mediated kinetic inductance detectors for light detection

    NASA Astrophysics Data System (ADS)

    Cardani, L.; Colantoni, I.; Cruciani, A.; Di Domizio, S.; Vignati, M.; Bellini, F.; Casali, N.; Castellano, M. G.; Coppolecchia, A.; Cosmelli, C.; Tomei, C.

    2015-08-01

    The development of sensitive cryogenic light detectors is of primary interest for bolometric experiments searching for rare events like dark matter interactions or neutrino-less double beta decay. Thanks to their good energy resolution and the natural multiplexed read-out, Kinetic Inductance Detectors (KIDs) are particularly suitable for this purpose. To efficiently couple KIDs-based light detectors to the large crystals used by the most advanced bolometric detectors, active surfaces of several cm2 are needed. For this reason, we are developing phonon-mediated detectors. In this paper, we present the results obtained with a prototype consisting of four 40 nm thick aluminum resonators patterned on a 2 × 2 cm2 silicon chip, and calibrated with optical pulses and X-rays. The detector features a noise resolution ?E = 154 ą 7 eV and an (18 ą 2)% efficiency.

  6. Efficiency of TTAC's ORTEC IDM

    SciTech Connect

    Livesay, Jake; Combs, Jason C; Margrave, Timothy E; Miller, Ian J

    2012-08-01

    ORNL's Technical Testing and Analysis Center (TTAC) acquired a High Purity Germanium Detector (HPGe) from ORTEC - a variant called an Interchangeable Detection Module (IDM). This detector has excellent energy resolution as well as high intrinsic efficiency. The purpose of this report is to detail the determination of the efficiency curve of the IDM, so future measurements can quantify the (otherwise unknown) activity of sources. Without such a curve, the activity cannot be directly reported by use of the IDM alone - a separate device such as an ion chamber would be required. This builds upon the capability of TTAC. The method for determining the energy-dependent intrinsic efficiency is laid-out in this report. It's noteworthy that this basic technique can be applied to any spectroscopic radiation detector, independent of the specific type (e.g. NaI, CzT, ClYC).

  7. Efficiently Coupling Light to Superconducting Nanowire Single-Photon Detectors

    E-print Network

    Hu, Xiaolong

    We designed superconducting nanowire single-photon detectors (SNSPDs) integrated with silver optical antennae for free-space coupling and a dielectric waveguide for fiber coupling. According to our finite-element simulation, ...

  8. Development of an underground HPGe array facility for ultra low radioactivity measurements

    NASA Astrophysics Data System (ADS)

    Sala, E.; Hahn, I. S.; Kang, W. G.; Kim, G. W.; Kim, Y. D.; Lee, M. H.; Leonard, D. S.; Park, S. Y.

    2015-08-01

    Low Level Counting techniques using low background facilities are continuously under development to increase the possible sensitivity needed for rare physics events experiments. The CUP (Center for Underground Physics) group of IBS is developing, in collaboration with Canberra, a ultra low background instrument composed of two arrays facing each other with 7 HPGe detectors each. The low radioactive background of each detector has been evaluated and improved by the material selection of the detector components. Samples of all the building materials have been provided by the manufacturer and the contaminations had been measured using an optimized low background 100% HPGe with a dedicated shielding. The evaluation of the intrinsic background has been performed using MonteCarlo simulations and considering the contribution of each material with the measured contamination. To further reduce the background, the instrument will be placed in the new underground laboratory at YangYang exploiting the 700m mountain coverage and radon-free air supplying system. The array has been designed to perform various Ultra Low background measurements; the sensitivity we are expecting will allow not only low level measurements of Ra and Th contaminations in Copper or other usually pure materials, but also the search for rare decays. In particular some possible candidates and configurations to detect the 0?ECEC (for example 106Cd and 156Dy) and rare ? decays (96Zr, 180mTa , etc ) are under study.

  9. Evaluation of HPGe spectrometric devices in monitoring the level of radioactive contamination in metallurgical industry

    NASA Astrophysics Data System (ADS)

    Petrucci, A.; Arnold, D.; Burda, O.; De Felice, P.; Garcia-Torańo, E.; Mejuto, M.; Peyres, V.; Šolc, J.; Vodenik, B.

    2015-10-01

    This paper presents the results of the tests of High Purity Germanium (HPGe) based gamma spectrometers employed for radioactivity control carried out on a daily basis in steel factories. This new application of this type of detector is part of the Joint Research Project (JRP) MetroMETAL supported by the European Metrology Research Programme (EMRP). The final purpose of the project was the improvement and standardisation of the measurement methods and systems for the control of radioactivity of recycled metal scraps at the beginning of the working process and for the certification of the absence of any radioactive contamination above the clearance levels (IAEA-TECDOC-8S5) in final steel products, Clearance levels for radionuclides in solid materials: application of exemption principles). Two prototypes based on HPGe detectors were designed and assembled to suit the needs of steel mills which had been examined previously. The evaluation of the two prototypes, carried out at three steel factories with standard sources of 60Co, 137Cs, 192Ir, 226Ra and 241Am in three different matrices (slag, fume dust and cast steel) and with samples provided on-site by the factories, was successful. The measurements proved the superiority of the prototypes over the scintillation detectors now commonly used regarding energy resolution and multi-nuclide identification capability. The detection limits were assessed and are presented as well.

  10. Efficient superconducting-nanowire single-photon detectors and their applications in quantum optics

    E-print Network

    Hu, Xiaolong, Ph. D. Massachusetts Institute of Technology

    2011-01-01

    Superconducting-nanowire single-photon detectors (SNSPDs) are an emerging technology for infrared photon counting and detection. Their advantages include good device efficiency, fast operating speed, low dark-count rate, ...

  11. True coincidence summing correction and mathematical efficiency modeling of a well detector

    NASA Astrophysics Data System (ADS)

    Jäderström, H.; Mueller, W. F.; Atrashkevich, V.; Adekola, A. S.

    2015-06-01

    True coincidence summing (TCS) occurs when two or more photons are emitted from the same decay of a radioactive nuclide and are detected within the resolving time of the gamma ray detector. TCS changes the net peak areas of the affected full energy peaks in the spectrum and the nuclide activity is rendered inaccurate if no correction is performed. TCS is independent of the count rate, but it is strongly dependent on the peak and total efficiency, as well as the characteristics of a given nuclear decay. The TCS effects are very prominent for well detectors because of the high efficiencies, and make accounting for TCS a necessity. For CANBERRA's recently released Small Anode Germanium (SAGe) well detector, an extension to CANBERRA's mathematical efficiency calibration method (In Situ Object Calibration Software or ISOCS, and Laboratory SOurceless Calibration Software or LabSOCS) has been developed that allows for calculation of peak and total efficiencies for SAGe well detectors. The extension also makes it possible to calculate TCS corrections for well detectors using the standard algorithm provided with CANBERRAS's Spectroscopy software Genie 2000. The peak and total efficiencies from ISOCS/LabSOCS have been compared to MCNP with agreements within 3% for peak efficiencies and 10% for total efficiencies for energies above 30 keV. A sample containing Ra-226 daughters has been measured within the well and analyzed with and without TCS correction and applying the correction factor shows significant improvement of the activity determination for the energy range 46-2447 keV. The implementation of ISOCS/LabSOCS for well detectors offers a powerful tool for efficiency calibration for these detectors. The automated algorithm to correct for TCS effects in well detectors makes nuclide specific calibration unnecessary and offers flexibility in carrying out gamma spectral analysis.

  12. NEUTRON DETECTION EFFICIENCY OF THE CLAS12 DETECTOR

    E-print Network

    Gilfoyle, Jerry

    , and probing new and exciting features of the fundamental constituents of matter. The current detector housed]. The new CLAS12 will rely on layers of drift chambers, Cherenkov counters, time-of-flight scintillators particles. Scintillators are a layer of material that release light when a particle travels through it

  13. Efficient Soft-Input Soft-Output MIMO Chase Detectors for Arbitrary Number of Streams

    NASA Astrophysics Data System (ADS)

    Gomaa, Ahmad; Jalloul, Louay M.-A.

    2015-08-01

    We present novel soft-input soft-output (SISO) multiple-input multiple-output (MIMO) detectors based on the Chase detection principle [1] in the context of iterative and decoding (IDD). The proposed detector complexity is linear in the signal modulation constellation size and the number of spatial streams. Two variants of the SISO detector are developed, referred to as SISO B-Chase and SISO L-Chase. An efficient method is presented that uses the decoder output to modulate the signal constellation decision boundaries inside the detector leading to the SISO detector architecture. The performance of these detectors significantly improves with just a few number of IDD iterations. The effect of transmit and receive antenna correlation is simulated. For the high-correlation case, the superiority of SISO B-Chase over the SISO L-Chase is demonstrated.

  14. Note: Fast neutron efficiency in CR-39 nuclear track detectors

    SciTech Connect

    Cavallaro, S.

    2015-03-15

    CR-39 samples are commonly employed for fast neutron detection in fusion reactors and in inertial confinement fusion experiments. The literature reported efficiencies are strongly depending on experimental conditions and, in some cases, highly dispersed. The present note analyses the dependence of efficiency as a function of various parameters and experimental conditions in both the radiator-assisted and the stand-alone CR-39 configurations. Comparisons of literature experimental data with Monte Carlo calculations and optimized efficiency values are shown and discussed.

  15. Quantum efficiency test set up performances for NIR detector characterization at ESTEC

    NASA Astrophysics Data System (ADS)

    Crouzet, P.-E.; Duvet, L.; De Wit, F.; Beaufort, T.; Blommaert, S.; Butler, B.; Van Duinkerken, G.; ter Haar, J.; Heijnen, J.; van der Luijt, K.; Smit, H.; Viale, T.

    2014-07-01

    The Payload Technology Validation Section (Future mission preparation Office) at ESTEC is in charge of specific mission oriented validation activities, for science and robotic exploration missions, aiming at reducing development risks in the implementation phase. These activities take place during the early mission phases or during the implementation itself. In this framework, a test set up to characterize the quantum efficiency of near infrared detectors has been developed. The first detector to be tested will an HAWAII-2RG detector with a 2.5?m cut off, it will be used as commissioning device in preparation to the tests of prototypes European detectors developed under ESA funding. The capability to compare on the same setup detectors from different manufacturers will be a unique asset for the future mission preparation office. This publication presents the performances of the quantum efficiency test bench to prepare measurements on the HAWAII-2RG detector. A SOFRADIR Saturn detector has been used as a preliminary test vehicle for the bench. A test set up with a lamp, chopper, monochromator, pinhole and off axis mirrors allows to create a spot of 1mm diameter between 700nm and 2.5?m.The shape of the beam has been measured to match the rms voltage read by the Merlin Lock -in amplifier and the amplitude of the incoming signal. The reference detectors have been inter-calibrated with an uncertainty up to 3 %. For the measurement with HAWAII-2RG detector, the existing cryostat [1] has been modified to adapt cold black baffling, a cold filter wheel and a sapphire window. An statistic uncertainty of +/-2.6% on the quantum efficiency on the detector under test measurement is expected.

  16. High-speed and high-efficiency superconducting nanowire single photon detector array.

    PubMed

    Rosenberg, D; Kerman, A J; Molnar, R J; Dauler, E A

    2013-01-28

    Superconducting nanowire single photon detectors (SNSPDs) have separately demonstrated high efficiency, low noise, and extremely high speed when detecting single photons. However, achieving all of these simultaneously has been limited by detector subtleties and tradeoffs. Here, we report an SNSPD system with <80 ps timing resolution, kHz noise count rates, and 76% fiber-coupled system detection efficiency in the low-flux limit at 1550 nm. We present a model for determining the detection efficiency penalty due to the detection recovery time, and we validate our method using experimental data obtained at high count rates. We demonstrate improved performance tradeoffs, such as 68% system detection efficiency, including losses due to detector recovery time, when coupled to a Poisson source emitting 100 million photons per second. Our system can provide limited photon number resolution, continuous cryogen-free operation, and scalability to future imaging and GHz-count-rate applications. PMID:23389125

  17. Note: fast neutron efficiency in CR-39 nuclear track detectors.

    PubMed

    Cavallaro, S

    2015-03-01

    CR-39 samples are commonly employed for fast neutron detection in fusion reactors and in inertial confinement fusion experiments. The literature reported efficiencies are strongly depending on experimental conditions and, in some cases, highly dispersed. The present note analyses the dependence of efficiency as a function of various parameters and experimental conditions in both the radiator-assisted and the stand-alone CR-39 configurations. Comparisons of literature experimental data with Monte Carlo calculations and optimized efficiency values are shown and discussed. PMID:25832287

  18. Coincidence summing corrections for a clover detector

    NASA Astrophysics Data System (ADS)

    Agarwal, Chhavi; Danu, L. S.; Gathibandhe, M.; Goswami, A.; Biswas, D. C.

    2014-11-01

    The true coincidence summing effect on the full energy peak efficiency calibration of a clover HPGe detector for point sources has been determined as a function of sample-to-detector distance using mono-energetic and multi-energetic gamma ray sources. The coincidence summing effect has been observed to increase at closer distances with the correction factors as high as 1.25 at closest distance studied. The correction factors for the total and the photopeak efficiencies have been obtained using the analytical method. The clover detector response has been simulated using MCNP code, taking care of the bevels and the flat surfaces of the clover detector. The geometry of the clover detector has been optimized to match the experimental and the theoretical efficiencies. The true coincidence summing correction factors (kTCS) have also been experimentally obtained by taking the ratio of corresponding mono-energetic extrapolated efficiencies to multi-energetic efficiencies. The kTCS obtained from analytical method has been found to match with the experimental kTCS with the simulated values within 1-5%.

  19. Efficiency of Moderated Neutron Lithium Glass Detectors Using Monte Carlo Techniques

    NASA Astrophysics Data System (ADS)

    James, Brian

    2011-10-01

    Due to national security concerns over the smuggling of special nuclear materials and the small supply of He-3 for use in neutron detectors, there is a great need for a new kind of neutron detector. Using Monte Carlo techniques I have been studying the use of lithium glass in varying configurations for neutron detectors. My research has included the effects of using a detector with two thin sheets of lithium at varying distances apart. I have also researched the effects of varying amounts of shielding a californium source with varying amounts of water. This is important since shielding would likely be used to make nuclear material more difficult to detect. The addition of one sheet of lithium-6 glass on the front surface of the detector significantly improves the efficiency for the detection of neutrons from a moderated fission source.

  20. High-temperature characteristics of charge collection efficiency using single CVD diamond detectors

    NASA Astrophysics Data System (ADS)

    Tsubota, Masakatsu; Kaneko, Junichi H.; Miyazaki, Daijirou; Shimaoka, Takehiro; Ueno, Katsunori; Tadokoro, Takahiro; Chayahara, Akiyoshi; Watanabe, Hideyuki; Kato, Yukako; Shikata, Shin-ichi; Kuwabara, Hitoshi

    2015-07-01

    We synthesized single-crystal diamonds using microwave assisted plasma chemical vapor deposition and evaluated the temperature dependence of the diamond radiation detectors. We achieved charge collection efficiency of the hole of 96.9% with 3.0% energy resolution at 473 K. In the case of electrons, they became undetectable at temperatures higher than 373 K. It is possible that carrier trapping generated with frequency or the leakage current increased. The detector produced by the diamond in Diamond Detector Ltd. detector, operates normally at 523 K. Electrons can be measured at 573 K. We discussed the characteristics of charge carrier transport in the diamond detector to prepare for future use at higher temperatures.

  1. CHANTI: a Fast and Efficient Charged Particle Veto Detector for the NA62 Experiment at CERN

    E-print Network

    Ambrosino, F; Di Filippo, D; Massarotti, P; Mirra, M; Napolitano, M; Palladino, V; Saracino, G; Roscilli, L; Vanzanella, A; Corradi, G; Tagnani, D; Paglia, U

    2015-01-01

    The design, construction and test of a charged particle detector made of scintillation counters read by Silicon Photomultipliers (SiPM) is described. The detector, which operates in vacuum and is used as a veto counter in the NA62 experiment at CERN, has a single channel time resolution of 1.14 ns, a spatial resolution of ~2.5 mm and an efficiency very close to 1 for penetrating charged particles.

  2. Bell inequalities violated using detectors of low efficiency

    NASA Astrophysics Data System (ADS)

    Pál, Károly F.; Vértesi, Tamás

    2015-11-01

    We define a family of binary-outcome n -party m ?n settings per party Bell inequalities whose members require the least detection efficiency for their violation among all known inequalities of the same type. This gives upper bounds for the minimum value of the critical efficiency—below which no violation is possible—achievable for such inequalities. For m =2 , our family reduces to the one given by Larsson and Semitecolos in 2001 [Phys. Rev. A 63, 022117 (2001), 10.1103/PhysRevA.63.022117]. For m >2 , a gap remains between these bounds and the best lower bounds. The violating state near the threshold efficiency always approaches a product state of n qubits.

  3. Efficient data transmission from silicon wafer strip detectors

    SciTech Connect

    Cooke, B.J.; Lackner, K.S.; Palounek, A.P.T.; Sharp, D.H.; Winter, L.; Ziock, H.J.

    1991-12-31

    An architecture for on-wafer processing is proposed for central silicon-strip tracker systems as they are currently designed for high energy physics experiments at the SSC, and for heavy ion experiments at RHIC. The data compression achievable with on-wafer processing would make it possible to transmit all data generated to the outside of the detector system. A set of data which completely describes the state of the wafer for low occupancy events and which contains important statistical information for more complex events can be transmitted immediately. This information could be used in early trigger decisions. Additional data packages which complete the description of the state of the wafer vary in size and are sent through a second channel. By buffering this channel the required bandwidth can be kept far below the peak data rates which occur in rate but interesting events. 18 refs.

  4. Practical Attacks on Decoy State Quantum Key Distribution Systems with Detector Efficiency Mismatch

    E-print Network

    Fei Yangyang; Gao Ming; Wang Weilong; Li Chaobo; Ma Zhi

    2015-07-23

    To the active basis choice decoy state quantum key distribution systems with detector efficiency mismatch, we present a modified attack strategy, which is based on faked states attack, with quantum nondemolition measurement ability to restress the threat of detector efficiency mismatch. Considering that perfect quantum nondemolition measurement ability dose not exist in real life, we also propose a practical attack strategy using photon number resolving detectors. Theoretical analysis and numerical simulation results show that, without changing the channel, our attack strategies are serious threats to decoy state quantum key distribution systems. The eavesdropper may get some information ab out the secret key without causing any alarms. Besides, the lower bound of detector efficiency mismatch to run our modified faked states attack successfully with perfect quantum nondemolition measurement ability is also given out, which provides the producers of quantum key distribution systems with a reference and can be treated as the approximate secure bound of detector efficiency mismatch in decoy state quantum key distribution systems.

  5. Practical attacks on decoy-state quantum-key-distribution systems with detector efficiency mismatch

    NASA Astrophysics Data System (ADS)

    Fei, Yangyang; Gao, Ming; Wang, Weilong; Li, Chaobo; Ma, Zhi

    2015-05-01

    To the active-basis-choice decoy-state quantum-key-distribution systems with detector efficiency mismatch, we present a modified attack strategy, which is based on the faked states attack, with quantum nondemolition measurement ability to restress the threat of detector efficiency mismatch. Considering that perfect quantum nondemolition measurement ability doesn't exist in real life, we also propose a practical attack strategy using photon number resolving detectors. Theoretical analysis and numerical simulation results show that, without changing the channel, our attack strategies are serious threats to decoy-state quantum-key-distribution systems. The eavesdropper may get some information about the secret key without causing any alarms. Besides, the lower bound of detector efficiency mismatch to run our modified faked states attack successfully with perfect quantum nondemolition measurement ability is also given out, which provides the producers of quantum-key-distribution systems with a reference and can be treated as the approximate secure bound of detector efficiency mismatch in decoy-state quantum-key-distribution systems.

  6. Efficient nanoplasmonic antennas for fabricating single protein molecule detector

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sharmistha; Dantham, Venkata Ramanaiah; Hussain, Sahid

    2015-06-01

    Real time (label-free) detection and sizing of single protein molecule at its natural state is "holy grail" in biosensing field. This non-destructive technique is useful for predicting the dangerous diseases at very early-stage. Herein, we report the synthesis and characterization of efficient nanoplasmonic antennas, which could be useful to fabricate an ultrasensitive nanoplasmonic-whispering gallery mode hybrid microresonator for the real time detection and sizing of single protein molecule. This hybrid microresonator could be easily converted as an ultrasensitive single molecule biosensor by anchoring suitable anti-bodies on the surface of the plasmonic nanoantenna.

  7. Impact of geometry on light collection efficiency of scintillation detectors for cryogenic rare event searches

    E-print Network

    F. A. Danevich; V. V. Kobychev; R. V. Kobychev; H. Kraus; V. B. Mikhailik; V. M. Mokina; I. M. Solsky

    2014-04-30

    Simulations of photon propagation in scintillation detectors were performed with the aim to find the optimal scintillator geometry, surface treatment, and shape of external reflector in order to achieve maximum light collection efficiency for detector configurations that avoid direct optical coupling, a situation that is commonly found in cryogenic scintillating bolometers in experimental searches for double beta decay and dark matter. To evaluate the light collection efficiency of various geometrical configurations we used the ZEMAX ray-tracing software. It was found that scintillators in the shape of a triangular prism with an external mirror shaped as truncated cone gives the highest light collection efficiency. The results of the simulations were confirmed by carrying out measurements of the light collection efficiencies of CaWO4 crystal scintillators. A comparison of simulated and measured values of light output shows good agreement

  8. Detectors

    DOEpatents

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

    2002-01-01

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

  9. Waveguide integrated superconducting single-photon detectors with high internal quantum efficiency at telecom wavelengths

    PubMed Central

    Kahl, Oliver; Ferrari, Simone; Kovalyuk, Vadim; Goltsman, Gregory N.; Korneev, Alexander; Pernice, Wolfram H. P.

    2015-01-01

    Superconducting nanowire single-photon detectors (SNSPDs) provide high efficiency for detecting individual photons while keeping dark counts and timing jitter minimal. Besides superior detection performance over a broad optical bandwidth, compatibility with an integrated optical platform is a crucial requirement for applications in emerging quantum photonic technologies. Here we present SNSPDs embedded in nanophotonic integrated circuits which achieve internal quantum efficiencies close to unity at 1550?nm wavelength. This allows for the SNSPDs to be operated at bias currents far below the critical current where unwanted dark count events reach milli-Hz levels while on-chip detection efficiencies above 70% are maintained. The measured dark count rates correspond to noise-equivalent powers in the 10?19?W/Hz?1/2 range and the timing jitter is as low as 35?ps. Our detectors are fully scalable and interface directly with waveguide-based optical platforms. PMID:26061283

  10. Waveguide integrated superconducting single-photon detectors with high internal quantum efficiency at telecom wavelengths.

    PubMed

    Kahl, Oliver; Ferrari, Simone; Kovalyuk, Vadim; Goltsman, Gregory N; Korneev, Alexander; Pernice, Wolfram H P

    2015-01-01

    Superconducting nanowire single-photon detectors (SNSPDs) provide high efficiency for detecting individual photons while keeping dark counts and timing jitter minimal. Besides superior detection performance over a broad optical bandwidth, compatibility with an integrated optical platform is a crucial requirement for applications in emerging quantum photonic technologies. Here we present SNSPDs embedded in nanophotonic integrated circuits which achieve internal quantum efficiencies close to unity at 1550 nm wavelength. This allows for the SNSPDs to be operated at bias currents far below the critical current where unwanted dark count events reach milli-Hz levels while on-chip detection efficiencies above 70% are maintained. The measured dark count rates correspond to noise-equivalent powers in the 10(-19) W/Hz(-1/2) range and the timing jitter is as low as 35 ps. Our detectors are fully scalable and interface directly with waveguide-based optical platforms. PMID:26061283

  11. Efficient one-pair experimental system for spatial resolution demonstration of prototype PET detectors.

    PubMed

    Tashima, Hideaki; Yoshida, Eiji; Hirano, Yoshiyuki; Nishikido, Fumihiko; Inadama, Naoko; Murayama, Hideo; Yamaya, Taiga

    2014-07-01

    In the development of depth-of-interaction (DOI)-positron emission tomography (PET) detectors, one of the important steps toward their practical use is an evaluation of their imaging performance, such as the spatial resolution as measured by use of a point source and a one-pair experimental system which simulates actual PET geometries. The DOI-PET detectors have a broad field of view providing good imaging performance compared with conventional detectors. Therefore, evaluation including the region from the center to the periphery close to the detector ring is required in an effort to show their advanced performance regarding uniform spatial resolution. In this study, we aimed to develop and evaluate an efficient one-pair experimental system for demonstration of the DOI-PET detector performance. For this purpose, we propose a one-pair experimental system that can simulate an arbitrary ring diameter and acquire projection data efficiently by skipping unnecessary combinations according to the position of the point source. As a result, the proposed system and our measuring scheme could significantly reduce the total measurement time, especially for a large ring size such as that used in brain PET scanners and whole-body PET scanners. We used the system to evaluate the X'tal cube PET detector with a 2-mm cubic crystal array arranged in simulated PET geometries with ring diameters of 8.2 and 14.6 cm for 12 and 18 detector blocks, respectively. The results showed that a uniform spatial resolution was achieved even in the peripheral region, and measurements were obtained semi-automatically in a short time. PMID:24938490

  12. Real time method and computer system for identifying radioactive materials from HPGe gamma-ray spectroscopy

    DOEpatents

    Rowland, Mark S. (Alamo, CA); Howard, Douglas E. (Livermore, CA); Wong, James L. (Dublin, CA); Jessup, James L. (Tracy, CA); Bianchini, Greg M. (Livermore, CA); Miller, Wayne O. (Livermore, CA)

    2007-10-23

    A real-time method and computer system for identifying radioactive materials which collects gamma count rates from a HPGe gamma-radiation detector to produce a high-resolution gamma-ray energy spectrum. A library of nuclear material definitions ("library definitions") is provided, with each uniquely associated with a nuclide or isotope material and each comprising at least one logic condition associated with a spectral parameter of a gamma-ray energy spectrum. The method determines whether the spectral parameters of said high-resolution gamma-ray energy spectrum satisfy all the logic conditions of any one of the library definitions, and subsequently uniquely identifies the material type as that nuclide or isotope material associated with the satisfied library definition. The method is iteratively repeated to update the spectrum and identification in real time.

  13. Comparison of two HPGe counting system used in activation studies for nuclear astrophysics

    SciTech Connect

    Szücs, T.; Kiss, G. G.; Fülöp, Zs.

    2014-05-09

    The activation method is a widely used technique to measure charged-particle induced cross sections for astrophys-ical applications. This two step technique is used for example to measure alpha-induced cross sections in ?-process related studies. The first step – in which a target is irradiated with a proton/alpha beam – is followed by the determination of the produced activity. Especially in p-process related studies in the heavier mass range, the produced radioactive nuclei decays mainly with electron-capture, resulting intense x-rays. The activity of the reaction products hence can be determine via the counting of these x-rays, and not only by counting the usually much weaker ?-rays. In this paper we compare the minimum detectable activity (MDA) of two High Purity Germanium (HPGe) detectors used for x- and ?-ray counting in activation experiments.

  14. Bragg Magnifier: High-efficiency, High-resolution X-ray Detector

    SciTech Connect

    Stampanoni, Marco; Groso, Amela; Abela, Rafael; Borchert, Gunther

    2007-01-19

    X-ray computer microtomography is a powerful tool for non-destructive examinations in medicine, biology, and material sciences. The resolution of the presently used detector systems is restricted by scintillator properties, optical light transfer, and charge-coupled-device (CCD) granularity, which impose a practical limit of about one micrometer spatial resolution at detector efficiencies of a few percent. A recently developed detector, called Bragg Magnifier, achieves a breakthrough in this respect, satisfying the research requirements of an efficient advance towards the submicron range. The Bragg Magnifier uses the properties of asymmetric Bragg diffraction to increase the cross section of the diffracted X-ray beam. Magnifications up to 100x100 can be achieved even at hard X-rays energies (>20 keV). In this way the influence of the detector resolution can be reduced accordingly and the efficiency increased. Such a device has been developed and successfully integrated into the Tomography Station of the Materials Science Beamline of the Swiss Light Source (SLS). The device can be operated at energies ranging from 17.5 keV up to 22.75 keV, reaching theoretical pixel sizes of 140 nm.

  15. High optical efficiency and photon noise limited sensitivity of microwave kinetic inductance detectors using phase readout

    NASA Astrophysics Data System (ADS)

    Janssen, R. M. J.; Baselmans, J. J. A.; Endo, A.; Ferrari, L.; Yates, S. J. C.; Baryshev, A. M.; Klapwijk, T. M.

    2013-11-01

    We demonstrate photon noise limited performance in both phase and amplitude readout in microwave kinetic inductance detectors (MKIDs) consisting of NbTiN and Al, down to 100 fW of optical power. We simulate the far field beam pattern of the lens-antenna system used to couple radiation into the MKID and derive an aperture efficiency of 75%. This is close to the theoretical maximum of 80% for a single-moded detector. The beam patterns are verified by a detailed analysis of the optical coupling within our measurement setup.

  16. High optical efficiency and photon noise limited sensitivity of microwave kinetic inductance detectors using phase readout

    SciTech Connect

    Janssen, R. M. J. Endo, A.; Baselmans, J. J. A.; Ferrari, L.; Yates, S. J. C.; Baryshev, A. M.; Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen ; Klapwijk, T. M.; Physics Department, Moscow State Pedagogical University, Moscow 119991

    2013-11-11

    We demonstrate photon noise limited performance in both phase and amplitude readout in microwave kinetic inductance detectors (MKIDs) consisting of NbTiN and Al, down to 100 fW of optical power. We simulate the far field beam pattern of the lens-antenna system used to couple radiation into the MKID and derive an aperture efficiency of 75%. This is close to the theoretical maximum of 80% for a single-moded detector. The beam patterns are verified by a detailed analysis of the optical coupling within our measurement setup.

  17. A Mechanically-Cooled, Highly-Portable, HPGe-Based, Coded-Aperture Gamma-Ray Imager

    SciTech Connect

    Ziock, Klaus-Peter; Boehnen, Chris Bensing; Hayward, Jason P; Raffo-Caiado, Ana Claudia

    2010-01-01

    Coded-aperture gamma-ray imaging is a mature technology that is capable of providing accurate and quantitative images of nuclear materials. Although it is potentially of high value to the safeguards and arms-control communities, it has yet to be fully embraced by those communities. One reason for this is the limited choice, high-cost, and low efficiency of commercial instruments; while instruments made by research organizations are frequently large and / or unsuitable for field work. In this paper we present the results of a project that mates the coded-aperture imaging approach with the latest in commercially-available, position-sensitive, High Purity Germanium (HPGe) detec-tors. The instrument replaces a laboratory prototype that, was unsuitable for other than demonstra-tions. The original instrument, and the cart on which it is mounted to provide mobility and pointing capabilities, has a footprint of ~ 2/3 m x 2 m, weighs ~ 100 Kg, and requires cryogen refills every few days. In contrast, the new instrument is tripod mounted, weighs of order 25 Kg, operates with a laptop computer, and is mechanically cooled. The instrument is being used in a program that is ex-ploring the use of combined radiation and laser scanner imaging. The former provides information on the presence, location, and type of nuclear materials while the latter provides design verification information. To align the gamma-ray images with the laser scanner data, the Ge imager is fitted and aligned to a visible-light stereo imaging unit. This unit generates a locus of 3D points that can be matched to the precise laser scanner data. With this approach, the two instruments can be used completely independently at a facility, and yet the data can be accurately overlaid based on the very structures that are being measured.

  18. Detective quantum efficiency model of single-X-ray-photon counting hybrid pixel detectors

    NASA Astrophysics Data System (ADS)

    Marchal, Julien; Medjoubi, Kadda

    2012-11-01

    A Detective Quantum Efficiency (DQE) model of single-X-ray-Photon Counting Hybrid Pixel Detectors (PC-HPDs) is presented. It applies to PC-HPDs based on semiconductor sensors such as silicon and CdTe pixel sensors. Charge-sharing effects are introduced in the expressions of imaging performance parameters such as large-area gain factor, presampling modulation transfer function and digital noise power spectrum, using the concept of threshold-dependent effective fill-factor. A simple X-ray induced charge distribution approximation is used to derive a practical formula for the threshold-dependent large-area gain factor, i.e. the integral X-ray spectrum which can be indirectly measured with a PC-HPD. This detector model was applied to standard synchrotron X-ray PC-HPDs: MEDIPIX3, PILATUS and XPAD detectors.

  19. Development of a high efficiency personal/environmental radon dosimeter using polycarbonate detectors.

    PubMed

    Taheri, M; Jafarizadeh, M; Baradaran, S; Zainali, Gh

    2006-12-01

    Passive radon dosimeters, based on alpha particle etched track detectors, are widely used for the assessment of radon exposure. These methods are often applied in radon dosimetry for long periods of time. In this research work, we have developed a highly efficient method of personal/environmental radon dosimetry that is based upon the detection of alpha particles from radon daughters, (218)Po and (214)Po, using a polycarbonate detector (PC). The radon daughters are collected on the filter surface by passing a fixed flow of air through it and the PC detector, placed at a specified distance from the filter, is simultaneously exposed to alpha particles. After exposure, the latent tracks on the detector are made to appear by means of an electrochemical etching process; these are proportional to the radon dose. The air flow rate and the detector-filter distance are the major factors that can affect the performance of the dosimeter. The results obtained in our experimental investigations have shown that a distance of 1.5 cm between the detector and the filter, an absorber layer of Al with a thickness of 12 microm and an air flow rate of 4 l min(-1) offer the best design parameters for a high efficiency radon dosimeter. Then, the designed dosimeter was calibrated against different values of radon exposures and the obtained sensitivity was found to be 2.1 (tracks cm(-2)) (kBq h m(-3))(-1). The most important advantages of this method are that it is reliable, fast and convenient when used for radon dose assessment. In this paper, the optimized parameters of the dosimeter structure and its calibration procedure are presented and discussed. PMID:17146123

  20. Accurate and efficient modeling of the detector response in small animal multi-head PET systems

    NASA Astrophysics Data System (ADS)

    Cecchetti, Matteo; Moehrs, Sascha; Belcari, Nicola; Del Guerra, Alberto

    2013-10-01

    In fully three-dimensional PET imaging, iterative image reconstruction techniques usually outperform analytical algorithms in terms of image quality provided that an appropriate system model is used. In this study we concentrate on the calculation of an accurate system model for the YAP-(S)PET II small animal scanner, with the aim to obtain fully resolution- and contrast-recovered images at low levels of image roughness. For this purpose we calculate the system model by decomposing it into a product of five matrices: (1) a detector response component obtained via Monte Carlo simulations, (2) a geometric component which describes the scanner geometry and which is calculated via a multi-ray method, (3) a detector normalization component derived from the acquisition of a planar source, (4) a photon attenuation component calculated from x-ray computed tomography data, and finally, (5) a positron range component is formally included. This system model factorization allows the optimization of each component in terms of computation time, storage requirements and accuracy. The main contribution of this work is a new, efficient way to calculate the detector response component for rotating, planar detectors, that consists of a GEANT4 based simulation of a subset of lines of flight (LOFs) for a single detector head whereas the missing LOFs are obtained by using intrinsic detector symmetries. Additionally, we introduce and analyze a probability threshold for matrix elements of the detector component to optimize the trade-off between the matrix size in terms of non-zero elements and the resulting quality of the reconstructed images. In order to evaluate our proposed system model we reconstructed various images of objects, acquired according to the NEMA NU 4-2008 standard, and we compared them to the images reconstructed with two other system models: a model that does not include any detector response component and a model that approximates analytically the depth of interaction as detector response component. The comparisons confirm previous research results, showing that the usage of an accurate system model with a realistic detector response leads to reconstructed images with better resolution and contrast recovery at low levels of image roughness.

  1. An efficient, movable single-particle detector for use in cryogenic ultra-high vacuum environments.

    PubMed

    Spruck, Kaija; Becker, Arno; Fellenberger, Florian; Grieser, Manfred; von Hahn, Robert; Klinkhamer, Vincent; Novotný, Old?ich; Schippers, Stefan; Vogel, Stephen; Wolf, Andreas; Krantz, Claude

    2015-02-01

    A compact, highly efficient single-particle counting detector for ions of keV/u kinetic energy, movable by a long-stroke mechanical translation stage, has been developed at the Max-Planck-Institut für Kernphysik (Max Planck Institute for Nuclear Physics, MPIK). Both, detector and translation mechanics, can operate at ambient temperatures down to ?10 K and consist fully of ultra-high vacuum compatible, high-temperature bakeable, and non-magnetic materials. The set-up is designed to meet the technical demands of MPIK's Cryogenic Storage Ring. We present a series of functional tests that demonstrate full suitability for this application and characterise the set-up with regard to its particle detection efficiency. PMID:25725832

  2. Validation of Pulse Shape Simulation for Ge detectors in the MAJORANA DEMONSTRATOR

    NASA Astrophysics Data System (ADS)

    Shanks, Benjamin; Majorana Collaboration

    2015-04-01

    The MAJORANA DEMONSTRATOR expects to begin searching for neutrinoless double beta decay using 76 Ge-enriched detectors in 2015. The DEMONSTRATOR high purity germanium (HPGe) detectors are built in the p-type point contact (PPC) geometry. The electrode of a PPC detector is small and shallow, resulting in low intrinsic capacitance and bulk field strengths compared to the traditional coaxial HPGe configuration. These characteristics allow for discrimination of signal event candidates from background using pulse shape analysis (PSA). In order to fully understand the systematics and efficiencies of PSA cuts, the MAJORANA collaboration has developed a software package to simulate signal generation in PPC detectors. This code has been validated by comparing simulated pulses to the pulse shapes generated for given detectors using an external source. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics Program of the National Science Foundation, and the Sanford Underground Research Facility.

  3. Direct-Reaction Studies by Particle-Gamma Coincidence Spectroscopy Using HPGe-CsI and HPGe-Si Arrays

    SciTech Connect

    Allmond, James M

    2013-01-01

    Particle- and particle- - coincidence spectroscopy has several advantages in the study of direct reactions(particularly in inverse kinematics) since it can generally allow determination of: decay paths; high-precision level energies; multipolarities of transitions; and cross sections. Techniques for studying direct reactions by particle- coincidence spectroscopy are presented for two cases: (1) heavy-ion reactions with HPGe-CsI, and (2) light-ion reactions with HPGe-Si. Future direct-reaction studies with radioactive ion beams (RIBs) will mostly involve low beam intensities and inverse kinematics (i.e., Abeam>Atarget), which eliminates the traditional use of magnetic spectrometers. Particle- coincidence spectroscopy currently provides the most viable method to study direct reactions with nuclei of any level density. In the present study, the capabilities and limitations of the technique are explored.

  4. Direct-reaction studies by particle-{gamma} coincidence spectroscopy using Csi-Hpge and Si-Hpge arrays

    SciTech Connect

    Allmond, J. M.

    2013-04-19

    Particle-{gamma} and particle-{gamma}-{gamma} coincidence spectroscopy has several advantages in the study of direct reactions (particularly in inverse kinematics) since it can generally allow determination of: decay paths; high-precision level energies; multipolarities of transitions; and cross sections. Techniques for studying direct reactions by particle-{gamma} coincidence spectroscopy are presented for two cases: (1) heavy-ion reactions with CsI-HPGe, and (2) light-ion reactions with Si-HPGe. Future direct-reaction studies with radioactive ion beams (RIBs) will mostly involve low beam intensities and inverse kinematics (i.e., A{sub beam}>A{sub target}), which eliminates the traditional use of magnetic spectrometers. Particle-{gamma} coincidence spectroscopy currently provides the most viable method to study direct reactions with nuclei of any level density. In the present study, the capabilities and limitations of the technique are explored.

  5. A new measurement of the neutron detection efficiency for the NaI Crystal Ball detector

    NASA Astrophysics Data System (ADS)

    Martemianov, M.; Kulikov, V.; Demissie, B. T.; Marinides, Z.; Akondi, C. S.; Annand, J. R. M.; Arends, H. J.; Beck, R.; Borisov, N.; Braghieri, A.; Briscoe, W. J.; Cherepnya, S.; Collicott, C.; Costanza, S.; Downie, E. J.; Dieterle, M.; Ferretti Bondy, M. I.; Fil'kov, L. V.; Garni, S.; Glazier, D. I.; Glowa, D.; Gradl, W.; Gurevich, G.; Hornidge, D.; Huber, G. M.; Kaeser, A.; Kashevarov, V. L.; Keshelashvili, I.; Kondratiev, R.; Korolija, M.; Krusche, B.; Lazarev, A.; Linturi, J. M.; Lisin, V.; Livingston, K.; MacGregor, I. J. D.; Manley, D. M.; Martel, P. P.; Middleton, D. G.; Miskimen, R.; Mushkarenkov, A.; Neganov, A.; Neiser, A.; Oberle, M.; Ostrick, M.; Ott, P.; Otte, P. B.; Oussena, B.; Pedroni, P.; Polonski, A.; Prakhov, S.; Ron, G.; Rostomyan, T.; Sarty, A.; Schott, D. M.; Schumann, S.; Sokhoyan, V.; Steffen, O.; Strakovsky, I. I.; Strub, Th.; Supek, I.; Thiel, M.; Thomas, A.; Unverzagt, M.; Usov, Yu. A.; Wagner, S.; Watts, D. P.; Wettig, J.; Werthmüller, D.; Witthauer, L.; Wolfes, M.

    2015-04-01

    We report on a measurement of the neutron detection efficiency in NaI crystals in the Crystal Ball detector obtained from a study of single ?0 photoproduction on deuterium using the tagged photon beam at the Mainz Microtron. The results were obtained up to a neutron energy of 400 MeV . They are compared to previous measurements made more than 15 years ago at the pion beam at the BNL AGS.

  6. A Bell Theorem Without Inequalities for Two Particles, Using Efficient Detectors

    E-print Network

    Daniel M. Greenberger; Michael Horne; Anton Zeilinger

    2008-08-01

    We consider an entangled two-particle state that is produced from two independent down-conversion sources by the process of "entanglement-swapping", so that the particles have never met. We prove a Greenberger-Horne-Zeilinger (GHZ) type theorem, showing that the quantum mechanical perfect correlations for such a state are inconsistent with any deterministic, local, realistic theory. This theorem holds for individual events with no inequalities, for detectors of 100% efficiency.

  7. A new measurement of the neutron detection efficiency for the NaI Crystal Ball detector

    E-print Network

    M. Martemianov; V. Kulikov; B. T. Demissie; Z. Marinides; C. S. Akondi; J. R. M. Annand; H. J. Arends; R. Beck; N. Borisov; A. Braghieri; W. J. Briscoe; S. Cherepnya; C. Collicott; S. Costanza; E. J. Downie; M. Dieterle; M. I. Ferretti Bondy; L. V. Filkov; S. Garni; D. I. Glazier; D. Glowa; W. Gradl; G. Gurevich; D. Hornidge; G. M. Huber; A. Kaeser; V. L. Kashevarov; I. Keshelashvili; R. Kondratiev; M. Korolija; B. Krusche; A. Lazarev; J. M. Linturi; V. Lisin; K. Livingston; I. J. D. MacGregor; D. M. Manley; P. P. Martel; D. G. Middleton; R. Miskimen; A. Mushkarenkov; A. Neganov; A. Neiser; M. Oberle; M. Ostrick; P. Ott; P. B. Otte; B. Oussena; P. Pedroni; A. Polonski; S. Prakhov; G. Ron; T. Rostomyan; A. Sarty; D. M. Schott; S. Schumann; V. Sokhoyan; O. Steffen; I. I. Strakovsky; Th. Strub; I. Supek; M. Thiel; A. Thomas; M. Unverzagt; Yu. A. Usov; S. Wagner; D. P. Watts; J. Wettig; D. Werthmuller; L. Witthauer; M. Wolfes

    2015-02-25

    We report on a measurement of the neutron detection efficiency in NaI crystals in the Crystal Ball detector obtained from a study of single p0 photoproduction on deuterium using the tagged photon beam at the Mainz Microtron. The results were obtained up to a neutron energy of 400 MeV. They are compared to previous measurements made more than 15 years ago at the pion beam at the BNL AGS.

  8. High-efficiency WSi superconducting nanowire single-photon detectors operating at 2.5?K

    SciTech Connect

    Verma, V. B.; Horansky, R. D.; Lita, A. E.; Mirin, R. P.; Nam, S. W.; Korzh, B.; Bussičres, F.; Zbinden, H.; Marsili, F.; Shaw, M. D.

    2014-09-22

    We investigate the operation of WSi superconducting nanowire single-photon detectors (SNSPDs) at 2.5?K, a temperature which is ?70% of the superconducting transition temperature (T{sub C}) of 3.4?K. We demonstrate saturation of the system detection efficiency at 78?ą?2% at a wavelength of 1310?nm, with a jitter of 191 ps. We find that the jitter at 2.5?K is limited by the noise of the readout and can be improved through the use of cryogenic amplifiers. Operation of SNSPDs with high efficiency at temperatures very close to T{sub C} appears to be a unique property of amorphous WSi.

  9. Detective quantum efficiency of photon-counting x-ray detectors

    SciTech Connect

    Tanguay, Jesse; Yun, Seungman; Kim, Ho Kyung; Cunningham, Ian A.

    2015-01-15

    Purpose: Single-photon-counting (SPC) x-ray imaging has the potential to improve image quality and enable novel energy-dependent imaging methods. Similar to conventional detectors, optimizing image SPC quality will require systems that produce the highest possible detective quantum efficiency (DQE). This paper builds on the cascaded-systems analysis (CSA) framework to develop a comprehensive description of the DQE of SPC detectors that implement adaptive binning. Methods: The DQE of SPC systems can be described using the CSA approach by propagating the probability density function (PDF) of the number of image-forming quanta through simple quantum processes. New relationships are developed to describe PDF transfer through serial and parallel cascades to accommodate scatter reabsorption. Results are applied to hypothetical silicon and selenium-based flat-panel SPC detectors including the effects of reabsorption of characteristic/scatter photons from photoelectric and Compton interactions, stochastic conversion of x-ray energy to secondary quanta, depth-dependent charge collection, and electronic noise. Results are compared with a Monte Carlo study. Results: Depth-dependent collection efficiency can result in substantial broadening of photopeaks that in turn may result in reduced DQE at lower x-ray energies (20–45 keV). Double-counting interaction events caused by reabsorption of characteristic/scatter photons may result in falsely inflated image signal-to-noise ratio and potential overestimation of the DQE. Conclusions: The CSA approach is extended to describe signal and noise propagation through photoelectric and Compton interactions in SPC detectors, including the effects of escape and reabsorption of emission/scatter photons. High-performance SPC systems can be achieved but only for certain combinations of secondary conversion gain, depth-dependent collection efficiency, electronic noise, and reabsorption characteristics.

  10. Quantum teleportation over 100 km of fiber using highly-efficient superconducting nanowire single photon detectors

    E-print Network

    Hiroki Takesue; Shellee D. Dyer; Martin J. Stevens; Varun Verma; Richard P. Mirin; Sae Woo Nam

    2015-10-02

    Quantum teleportation is an essential quantum operation by which we can transfer an unknown quantum state to a remote location with the help of quantum entanglement and classical communication. Since the first experimental demonstrations using photonic qubits and continuous variables, the distance of photonic quantum teleportation over free space channels has continued to increase and has reached >100 km. On the other hand, quantum teleportation over optical fiber has been challenging, mainly because the multi-fold photon detection that inevitably accompanies quantum teleportation experiments has been very inefficient due to the relatively low detection efficiencies of typical telecom-band single photon detectors. Here, we report efficient quantum teleportation over optical fiber using four high-detection efficiency superconducting nanowire superconducting single-photon detectors (SNSPD) based on MoSi. These SNSPDs make it possible to perform highly-efficient multi-fold photon measurements, allowing us to confirm that the quantum states of input photons were successfully teleported over 100 km of fiber.

  11. Quantum efficiency of Si Hybrid CMOS detectors in the soft X-ray band

    NASA Astrophysics Data System (ADS)

    Prieskorn, Zachary; Bongiorno, Stephen; Burrows, David; Falcone, Abraham; Griffith, Christopher; Nikoleyczik, Jonathan; Wells, Mark; PSU X-ray Instrumentation Group Team

    2015-04-01

    X-ray sensitive Si Hybrid CMOS detectors (HCDs) will potentially replace X-ray CCDs in the focal planes of future X-ray observatories. HCDs improve on the performance of CCDs in numerous areas: faster read out time, windowed read out mode, less susceptibility to radiation & micrometeoroid damage, and lower power consumption. Understanding the detector quantum efficiency (QE) is critical for estimating the sensitivity of an X-ray instrument. We report on the QE for multiple energies in the soft X-ray band of four HCDs based on the Teledyne Imaging Sensors HyViSITM detectors. These detectors have Al optical blocking filters deposited directly on the Si substrate; these filters vary in thickness from 180 - 1000 Ĺ. We estimate the QE with a 1D slab absorption model and find good agreement between the model and our results across an energy range from 0.677 - 8.05 keV. This work was supported by NASA Grants NNG05WC10G, NNX08AI64G, and NNX11AF98G.

  12. Analysis of the Texas A&M impact lightning detector to determine detection efficiency and site error corrections 

    E-print Network

    Leahy, Frank Byron

    1999-01-01

    The Texas A&M IMProved Accuracy from Combined Technology (IMPACT) lightning detector has been analyzed for 1997 and 1998-99 to determine detection characteristics. These characteristics include stroke detection efficiency as a function of range...

  13. High-speed and high-efficiency travelling wave single-photon detectors embedded in nanophotonic circuits

    PubMed Central

    Pernice, W.H.P.; Schuck, C.; Minaeva, O.; Li, M.; Goltsman, G.N.; Sergienko, A.V.; Tang, H.X.

    2012-01-01

    Ultrafast, high-efficiency single-photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. However, imperfect modal matching and finite photon absorption rates have usually limited their maximum attainable detection efficiency. Here we demonstrate superconducting nanowire detectors atop nanophotonic waveguides, which enable a drastic increase of the absorption length for incoming photons. This allows us to achieve high on-chip single-photon detection efficiency up to 91% at telecom wavelengths, repeatable across several fabricated chips. We also observe remarkably low dark count rates without significant compromise of the on-chip detection efficiency. The detectors are fully embedded in scalable silicon photonic circuits and provide ultrashort timing jitter of 18?ps. Exploiting this high temporal resolution, we demonstrate ballistic photon transport in silicon ring resonators. Our direct implementation of a high-performance single-photon detector on chip overcomes a major barrier in integrated quantum photonics. PMID:23271658

  14. High-speed and high-efficiency travelling wave single-photon detectors embedded in nanophotonic circuits.

    PubMed

    Pernice, W H P; Schuck, C; Minaeva, O; Li, M; Goltsman, G N; Sergienko, A V; Tang, H X

    2012-01-01

    Ultrafast, high-efficiency single-photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. However, imperfect modal matching and finite photon absorption rates have usually limited their maximum attainable detection efficiency. Here we demonstrate superconducting nanowire detectors atop nanophotonic waveguides, which enable a drastic increase of the absorption length for incoming photons. This allows us to achieve high on-chip single-photon detection efficiency up to 91% at telecom wavelengths, repeatable across several fabricated chips. We also observe remarkably low dark count rates without significant compromise of the on-chip detection efficiency. The detectors are fully embedded in scalable silicon photonic circuits and provide ultrashort timing jitter of 18 ps. Exploiting this high temporal resolution, we demonstrate ballistic photon transport in silicon ring resonators. Our direct implementation of a high-performance single-photon detector on chip overcomes a major barrier in integrated quantum photonics. PMID:23271658

  15. Use of the WNR spallation neutron source at LAMPF to determine the absolute efficiency of a neutron scintillation detector

    SciTech Connect

    Staples, P.A.; Egan, J.J.; Kegel, G.H.R.; Woodring, M.L.; DeSimone, D.J.; Lisowski, P.W.

    1994-06-01

    Prompt fission neutron spectrum measurements at the University of Massachusetts Lowell 5.5 MV Van de Graaff accelerator laboratory require that the neutron detector efficiency be well known over a neutron energy range of 100 keV to 20 MeV. The efficiency of the detector, has been determined for energies greater than 5.0 MeV using the Weapons Neutron Research (WNR) white neutron source at the Los Alamos Meson Physics Facility (LAMPF) in a pulsed beam, time-of-flight (TOF) experiment. Carbon matched polyethylene and graphite scatterers were used to obtain a hydrogen spectrum. The detector efficiency was determined using the well known H(n,n) scattering cross section. Results are compared to the detector efficiency calculation program SCINFUL available from the Radiation Shielding Information Center at Oak Ridge National Laboratory.

  16. Heterodyne detection at 300 GHz using glow discharge detectors with efficient quasi-optical design

    NASA Astrophysics Data System (ADS)

    Aharon Akram, Avihai; Rozban, Daniel; Levanon, Assaf; Abramovich, A.; Kopeika, N. S.

    2013-05-01

    A miniature neon indicator lamp, also known as a Glow Discharge Detector (GDD), costing about 50 cents, was found to be an excellent room temperature THz radiation detector. A proof of concept of 300 GHz heterodyne detection using GDD is demonstrated in this paper. Furthermore, a comparison to direct detection was carried-out and polarization effects on heterodyne detection were investigated. Preliminary results at 300 GHz showed better sensitivity by a factor of 20 with only 56 microwatt local oscillator power using heterodyne compared to direct detection. Further improvement of the detection sensitivity can be achieved if the Local Oscillator (LO) power (Plo) is increased. Effects of orthogonal polarizations of signal and local oscillator powers on heterodyne sensitivity were found to be surprisingly weak. More efficient quasi optical design for heterodyne detection is presented in this study, experimental results showed above 50% better performance compared to conventional ones.

  17. GRABGAM Analysis of Ultra-Low-Level HPGe Gamma Spectra

    SciTech Connect

    Winn, W.G.

    1999-07-28

    The GRABGAM code has been used successfully for ultra-low level HPGe gamma spectrometry analysis since its development in 1985 at Savannah River Technology Center (SRTC). Although numerous gamma analysis codes existed at that time, reviews of institutional and commercial codes indicated that none addressed all features that were desired by SRTC. Furthermore, it was recognized that development of an in-house code would better facilitate future evolution of the code to address SRTC needs based on experience with low-level spectra. GRABGAM derives its name from Gamma Ray Analysis BASIC Generated At MCA/PC.

  18. Ultra-Low Noise Mechanically Cooled Germanium Detector

    E-print Network

    Barton, Paul; Martin, Ryan; Vetter, Kai

    2015-01-01

    Low capacitance, large volume, high purity germanium (HPGe) radiation detectors have been successfully employed in low-background physics experiments. However, some physical processes may not be detectable with existing detectors whose energy thresholds are limited by electronic noise. In this paper, methods are presented which can lower the electronic noise of these detectors. Through ultra-low vibration mechanical cooling and wire bonding of a CMOS charge sensitive preamplifier to a sub-pF p-type point contact HPGe detector, we demonstrate electronic noise levels below 40 eV-FWHM.

  19. Numerical Simulations of Pillar Structured Solid State Thermal Neutron Detector Efficiency and Gamma Discrimination

    SciTech Connect

    Conway, A; Wang, T; Deo, N; Cheung, C; Nikolic, R

    2008-06-24

    This work reports numerical simulations of a novel three-dimensionally integrated, {sup 10}boron ({sup 10}B) and silicon p+, intrinsic, n+ (PIN) diode micropillar array for thermal neutron detection. The inter-digitated device structure has a high probability of interaction between the Si PIN pillars and the charged particles (alpha and {sup 7}Li) created from the neutron - {sup 10}B reaction. In this work, the effect of both the 3-D geometry (including pillar diameter, separation and height) and energy loss mechanisms are investigated via simulations to predict the neutron detection efficiency and gamma discrimination of this structure. The simulation results are demonstrated to compare well with the measurement results. This indicates that upon scaling the pillar height, a high efficiency thermal neutron detector is possible.

  20. Measuring the X-ray quantum efficiency of a hybrid CMOS detector with 55Fe

    NASA Astrophysics Data System (ADS)

    Bongiorno, S. D.; Falcone, A. D.; Prieskorn, Z.; Griffith, C.; Burrows, D. N.

    2015-06-01

    Charge coupled devices (CCDs) are currently the workhorse focal plane arrays operating aboard many orbiting astrophysics X-ray telescopes, e.g. Chandra, XMM-Newton, Swift, and Suzaku. In order to meet the count rate, power, and mission duration requirements defined by next-generation X-ray telescopes, future detectors will need to be read out faster, consume less power, and be more resistant to radiation and micrometeoroid damage than current-generation devices. The hybrid CMOS detector (HCD), a type of active pixel sensor, is currently being developed to meet these requirements. With a design architecture that involves bump bonding two semiconductor substrates together at the pixel level, these devices exhibit both the high read speed and low power consumption of CMOS readout circuitry and the high quantum efficiency (QE) of a deeply depleted silicon absorber. These devices are expected to exhibit the same excellent, high-energy quantum efficiency (QE) as deep-depletion CCDs (QE > 0.9 at 6 keV), while at the same time exhibiting superior readout flexibility, power consumption, and radiation hardness than CCDs. In this work we present a QE model for a Teledyne Imaging Sensors HyViSI HCD, which predicts QE=96% at 55Fe source energies (5.89 and 6.49 keV). We then present a QE measurement of the modeled device at the same energies, which shows QE=97ą5% and is in good agreement with the model.

  1. Minimum length Pb/SCIN detector for efficient cosmic ray identification

    NASA Technical Reports Server (NTRS)

    Snyder, H. David

    1989-01-01

    A study was made of the performance of a minimal length cosmic ray shower detector that would be light enough for space flight and would provide efficient identification of positions and protons. Cosmic ray positions are mainly produced in the decay chain of: Pion yields Muon yields Positron and they provide a measure of the matter density traversed by primary protons. Present positron flux measurements are consistent with the Leaky Box and Halo models for sources of cosmic rays. Abundant protons in the space environment are a significant source of background that would wash out the positron signal. Protons and positrons produced very distictive showers of particles when they enter matter; many studies have been published on their behavior on large calorimeter detectors. The challenge is to determine the minimal material necessary (minimal calorimeter depth) for positive particles identification. The primary instrument for the investigation is the Monte Carlo code GEANT, a library of programs from CERN that can be used to model experimental geometry, detector responses and particle interaction processes. The use of the Monte Carlo approach is crucial since statistical fluctuations in shower shape are significant. Studies conducted during the 1988 summer program showed that straightforward approaches to the problem achieved 85 to 90 percent correct identification, but left a residue of 10 to 15 percent misidentified particles. This percentage improved to a few percent when multiple shower-cut criteria were applied to the data. This summer, the same study was extended to employ several physical and statistical methods of identifying response of the calorimeter and the efficiency of the optimal shower cuts to off-normal incidence particle was determined.

  2. HAND-HELD GAMMA-RAY SPECTROMETER BASED ON HIGH-EFFICIENCY FRISCH-RING CdZnTe DETECTORS.

    SciTech Connect

    CUI,Y.

    2007-05-01

    Frisch-ring CdZnTe detectors have demonstrated good energy resolution, el% FWHM at 662 keV, and good efficiency for detecting gamma rays. This technique facilitates the application of CdZnTe materials for high efficiency gamma-ray detection. A hand-held gamma-ray spectrometer based on Frisch-ring detectors is being designed at Brookhaven National Laboratory. It employs an 8x8 CdZnTe detector array to achieve a high volume of 19.2 cm3, so that detection efficiency is significantly improved. By using the front-end ASICs developed at BNL, this spectrometer has a small profile and high energy resolution. The spectrometer includes signal processing circuit, digitization and storage circuit, high-voltage module, and USB interface. In this paper, we introduce the details of the system structure and report our test results with it.

  3. A high efficiency, low background neutron and gamma detector for cold fusion experiments

    NASA Astrophysics Data System (ADS)

    Stella, B.; Celani, F.; Corradi, M.; Ferrarotto, F.; Iucci, N.; Milone, V.; Spallone, A.; Villoresi, G.

    1995-02-01

    The present apparatus (named by the acrostic "FERMI" also to celebrate the 60 yr of the discovery, by Enrico Fermi and collaborators at Rome University, of the effects of moderation of neutrons) is mainly a moderated neutron detector developed for the search of cold fusion events. It is based on 7 BF 3 and 2 3He proportional counters with detection efficiency for neutrons 40%-8% in the range 1 keV-20 MeV, pulse shape acquisition and good time resolution for neutron bursts; it also allows us to perform a good reconstruction of the average original neutron energy. The neutron background measured in the Gran Sasso INFN underground laboratory is about 0.09 Hz. Gamma rays are revealed mostly by a complementary low background NaI detector with 26% solid angle coverage. The performances are controlled by a full MC simulation, experimentally tested. A high multiplicity (up to ˜ 100) neutrons' event has been detected during background runs. The system is being upgraded by the detection and identification of charged hadrons.

  4. Comparison of MCNP and Experimental Measurements for an HPGe-based Spectroscopy Portal Monitor.

    SciTech Connect

    Keyser, Ronald M.; Hensley, Walter K.; Twomey, Timothy R.; UPP, Daniel L.

    2008-05-15

    The necessity to monitor international commercial transportation for illicit nuclear materials resulted in the installation of many nuclear radiation detection systems in Portal Monitors. These were mainly gross counters which alarmed at any indication of high radioactivity in the shipment, the vehicle or even the driver. The innocent alarm rate, due to legal shipments of sources and NORM, or medical isotopes in patients, caused interruptions and delays in commerce while the legality of the shipment was verified. To overcome this difficulty, Department of Homeland Security (DHS) supported the writing of the ANSI N42.38 standard (Performance Criteria for Spectroscopy-Based Portal Monitors used for Homeland Security) to define the performance of a Portal Monitor with nuclide identification capabilities, called a Spectroscopy Portal Monitor. This standard defines detection levels and response characteristics for the system for energies from 25 keV to3. MeV. To accomplish the necessary performance, several different HPGe detector configurations were modeled using MCNP for the horizontal field of view (FOV) and vertical linearity of response over the detection zone of 5 meters by 4.5 meters for 661 keV as representative of the expected nuclides of interest. The configuration with the best result was built and tested. The results for the FOV as a function of energy and the linearity show good agreement with the model and performance exceeding the requirements of N42.38.

  5. Scintillation Efficiency for Low-Energy Nuclear Recoils in Liquid-Xenon Dark Matter Detectors

    E-print Network

    Wei Mu; Xiaonu Xiong; Xiangdong Ji

    2013-10-09

    We perform a theoretical study of the scintillation efficiency in the low-energy region crucial for liquid-xenon dark-matter detectors. We develop a computer program to simulate the cascading process of the recoiling xenon nucleus in liquid xenon and calculate the nuclear quenching effect due to atomic collisions. We use the electronic stopping power extrapolated from the experimental data to the low-energy region, and take into account the effects of electrons escaping from the electron-ion pair recombination using the generalized Thomas-Imel model fitted to scintillation data. Our result agrees well with the experiments from neutron scattering and vanishes rapidly as the recoiling energy drops below 3 keV.

  6. Three-dimensional diamond detectors: Charge collection efficiency of graphitic electrodes

    SciTech Connect

    Lagomarsino, S. Parrini, G.; Sciortino, S.; Department of Physics and Astronomy, University of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino ; Bellini, M.; Gorelli, F.; Santoro, M.; Istituto Nazionale di Ottica , Largo Enrico Fermi 6, 50125 Firenze ; Corsi, C.

    2013-12-02

    Implementation of 3D-architectures in diamond detectors promises to achieve unreached performances in the radiation-harsh environment of future high-energy physics experiments. This work reports on the collection efficiency under ?-irradiation of graphitic 3D-electrodes, created by laser pulses in the domains of nanoseconds (ns-made-sensors) and femtoseconds (fs-made-sensors). Full collection is achieved with the fs-made-sensors, while a loss of 25%–30% is found for the ns-made-sensors. The peculiar behaviour of ns-made sensors has been explained by the presence of a nano-structured sp{sup 3}-carbon layer around the graphitic electrodes, evidenced by micro-Raman imaging, by means of a numerical model of the charge transport near the electrodes.

  7. High efficiency photon counting detectors for the FAUST Spacelab far ultraviolet astronomy payload

    NASA Technical Reports Server (NTRS)

    Siegmund, O. H. W.; Lampton, M.; Bixler, J.; Vallerga, J.; Bowyer, S.

    1987-01-01

    The performances of sealed tube microchannel-plate position sensitive detectors having transmission CsI photocathodes or opaque CsI photocathodes are compared. These devices were developed for the FAUST Spacelab payload to accomplish imaging surveys in the band between 1300 A and 1800 A. It is demonstrated that photocathode quantum efficiencies in excess of 40 percent at 1216 A have been achieved with the transmission and the opaque CsI photocathodes. The effect of the photoelectron trajectory on the spatial resolution is assessed. Spatial resolution of less than 70 microns FWHM has been obtained and is maintained up to event rates of 50,000/sec. Background rates of 0.55 events sq cm per sec have been achieved and low distortion (less than 1 percent) imaging has been demonstrated.

  8. 4D STEM: High efficiency phase contrast imaging using a fast pixelated detector

    NASA Astrophysics Data System (ADS)

    Yang, H.; Jones, L.; Ryll, H.; Simson, M.; Soltau, H.; Kondo, Y.; Sagawa, R.; Banba, H.; MacLaren, I.; Nellist, P. D.

    2015-10-01

    Phase contrast imaging is widely used for imaging beam sensitive and weak phase objects in electron microscopy. In this work we demonstrate the achievement of high efficient phase contrast imaging in STEM using the pnCCD, a fast direct electron pixelated detector, which records the diffraction patterns at every probe position with a speed of 1000 to 4000 frames per second, forming a 4D STEM dataset simultaneously with the incoherent Z-contrast imaging. Ptychographic phase reconstruction has been applied and the obtained complex transmission function reveals the phase of the specimen. The results using GaN and Ti, Nd- doped BiFeO3 show that this imaging mode is especially powerful for imaging light elements in the presence of much heavier elements.

  9. Measurement of the Charge Collection Efficiency After Heavy Non-Uniform Irradiation in BABAR Silicon Detectors

    SciTech Connect

    Bettarini, S.; Bondioli, M.; Calderini, G.; Forti, F.; Marchiori, G.; Rizzo, G.; Giorgi, M.A.; Bosisio, L.; Dittongo, S.; Campagnari, C.; /UC, Santa Barbara

    2006-03-01

    We have investigated the depletion voltage changes, leakage current increase and charge collection efficiency of a silicon microstrip detector identical to those used in the inner layers of the BABAR Silicon Vertex Tracker (SVT) after heavy nonuniform irradiation. A full SVT module with the front-end electronics connected has been irradiated with a 0.9 GeV electron beam up to a peak fluence of 3.5 x 10{sup 14} e{sup -}/cm{sup 2}, well beyond the level causing substrate type inversion. We have irradiated the silicon with a nonuniform profile having {sigma} = 1.4 mm that simulates the conditions encountered in the BABAR experiment by the modules intersecting the horizontal machine plane. The position dependence of the charge collection properties and the depletion voltage have been investigated in detail using a 1060 nm LED and an innovative measuring technique based only on the digital output of the chip.

  10. Large-sensitive-area superconducting nanowire single-photon detector at 850 nm with high detection efficiency

    E-print Network

    Li, Hao; You, Lixing; Yang, Xiaoyan; Zhang, Weijun; Liu, Xiaoyu; Chen, Sijing; Wang, Zhen; Xie, Xiaoming

    2015-01-01

    Satellite-ground quantum communication requires single-photon detectors of 850-nm wavelength with both high detection efficiency and large sensitive area. We developed superconducting nanowire single-photon detectors (SNSPDs) on one-dimensional photonic crystals, which acted as optical cavities to enhance the optical absorption, with a sensitive-area diameter of 50 um. The fabricated multimode fiber coupled NbN SNSPDs exhibited a maximum system detection efficiency (DE) of up to 82% and a DE of 78% at a dark count rate of 100 Hz at 850-nm wavelength as well as a system jitter of 105 ps.

  11. Large-sensitive-area superconducting nanowire single-photon detector at 850 nm with high detection efficiency.

    PubMed

    Li, Hao; Zhang, Lu; You, Lixing; Yang, Xiaoyan; Zhang, Weijun; Liu, Xiaoyu; Chen, Sijing; Wang, Zhen; Xie, Xiaoming

    2015-06-29

    Satellite-ground quantum communication requires single-photon detectors of 850-nm wavelength with both high detection efficiency and large sensitive area. We developed superconducting nanowire single-photon detectors (SNSPDs) on one-dimensional photonic crystals, which acted as optical cavities to enhance the optical absorption, with a sensitive-area diameter of 50 ?m. The fabricated multimode fiber coupled NbN SNSPDs exhibited a maximum system detection efficiency (DE) of up to 82% and a DE of 78% at a dark count rate of 100 Hz at 850-nm wavelength as well as a system jitter of 105 ps. PMID:26191739

  12. Large-sensitive-area superconducting nanowire single-photon detector at 850 nm with high detection efficiency

    E-print Network

    Hao Li; Lu Zhang; Lixing You; Xiaoyan Yang; Weijun Zhang; Xiaoyu Liu; Sijing Chen; Zhen Wang; Xiaoming Xie

    2015-06-25

    Satellite-ground quantum communication requires single-photon detectors of 850-nm wavelength with both high detection efficiency and large sensitive area. We developed superconducting nanowire single-photon detectors (SNSPDs) on one-dimensional photonic crystals, which acted as optical cavities to enhance the optical absorption, with a sensitive-area diameter of 50 um. The fabricated multimode fiber coupled NbN SNSPDs exhibited a maximum system detection efficiency (DE) of up to 82% and a DE of 78% at a dark count rate of 100 Hz at 850-nm wavelength as well as a system jitter of 105 ps.

  13. Study of interstrip gap effects and efficiency for full energy detection of Double Sided Silicon Strip Detectors

    NASA Astrophysics Data System (ADS)

    Torresi, D.; Forneris, J.; Grassi, L.; Acosta, L.; Di Pietro, A.; Figuera, P.; Grilj, L.; Jaksi?, M.; Lattuada, M.; Mijatovi?, T.; Milin, M.; Prepolec, L.; Skukan, N.; Soi?, N.; Stanko, D.; Toki?, V.; Uroi?, M.; Zadro, M.

    2015-04-01

    In this work is reported a study on the response of double sided silicon strip detectors. In order to investigate the effect of the electrode segmentation on the detector response, two experiments were performed aimed to measure the efficiency for full energy detection. Results show that the efficiency for full energy detection, that is directly related to effective width of the inter-strip region, varies with both detected ion energy and bias voltage. The experimental results are qualitatively reproduced by a simplified model based on the Shockley-Ramo-Gunn framework.

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

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  15. Hand-Held Gamma-Ray Spectrometer Based on High-Efficiency Frisch-Ring Cdznte Detectors

    SciTech Connect

    Cui, Y.; Bolotnikov, A; Camarda, G; Hossain, A; James, R; DeGeronimo, G; Fried, J; O'Connor, P; Kargar, A; et. al.

    2008-01-01

    Frisch-ring CdZnTe detectors have demonstrated both good energy resolution, <1% FWHM at 662 keV, and good efficiency in detecting gamma rays, highlighting the strong potential of CdZnTe materials for such applications. We are designing a hand-held gamma-ray spectrometer based on Frisch-ring detectors at Brookhaven National Laboratory. It employs an 8 times 8 CdZnTe detector array to achieve a high volume of 19.2 cm3, so greatly improving detection efficiency. By using the front-end application-specific integrated circuits (ASICs) developed at BNL, this spectrometer has a small profile and high energy-resolution. It includes a signal processing circuit, digitization and storage circuits, a high-voltage module, and a universal serial bus (USB) interface. In this paper, we detail the system's structure and report the results of our tests with it.

  16. High efficiency microfluidic beta detector for pharmacokinetic studies in small animals

    NASA Astrophysics Data System (ADS)

    Convert, Laurence; Girard-Baril, Frédérique; Renaudin, Alan; Grondin, Étienne; Jaouad, Abdelatif; Aimez, Vincent; Charette, Paul; Lecomte, Roger

    2011-10-01

    New radiotracers are continuously being developed to improve diagnostic efficiency using Single Photon Emission Computed Tomography (SPECT) or Positron Emission Tomography (PET). The characterization of their pharmacokinetics requires blood radioactivity monitoring over time during the scan and is very challenging in small animals because of the low volume of blood available. In this work, a prototype microfluidic blood counter made of a microchannel atop a silicon substrate containing PIN photodiodes is proposed to improve beta detection efficiency in a small volume by eliminating unnecessary interfaces between fluid and detector. A flat rectangular-shaped epoxy channel, 36 ?m×1.26 mm cross section and 31.5 mm in length, was microfabricated over a die containing an array of 2×2 mm 2 PIN photodiodes, leaving only a few micrometers of epoxy floor layer between the fluid and the photodiode sensitive surface. This geometry leads to a quasi 2D source, optimizing geometrical detection efficiency that was estimated at 41% using solid angle calculation. CV- IV measurements were made at each fabrication step to confirm that the microchannel components had no significant effects on the diodes' electrical characteristics. The chip was wire-bonded to a PCB and connected to charge sensitive preamplifier and amplifier modules for pulse shaping. Energy spectra recorded for different isotopes showed continuous beta distribution for PET isotopes and monoenergetic conversion electron peaks for 99mTc. Absolute sensitivity was determined for the most popular PET and SPECT radioisotopes and ranged from 26% to 33% for PET tracers ( 18F, 13N, 11C, 68Ga) and more than 2% for 99mTc. Input functions were successfully simulated with 18F, confirming the setup's suitability for pharmacokinetic modeling of PET and SPECT radiotracers in animal experiments. By using standard materials and procedures, the fabrication process is well suited to on-chip microfluidic functionality, allowing full characterization of new radiotracers.

  17. HST/WFC3 UVIS Detector: Dark, Charge Transfer Efficiency, and Point Spread Function Calibrations

    NASA Astrophysics Data System (ADS)

    Bourque, Matthew; Anderson, Jay; Baggett, Sylvia; Bowers, Ariel; MacKenty, John W.; Sahu, Kailash C.

    2015-08-01

    Wide Field Camera 3 (WFC3) is a fourth-generation imaging instrument on board the Hubble Space Telescope (HST) that was installed during Servicing Mission 4 in May 2009. As one of two channels available on WFC3, the UVIS detector is comprised of two e2v CCDs and is sensitive to ultraviolet and visible light. Here we provide updates to the characterization and monitoring of the UVIS performance and stability. We present the long-term growth of the dark current and the hot pixel population, as well as the evolution of Charge Transfer Efficiency (CTE). We also discuss updates to the UVIS dark calibration products, which are used to correct for dark current in science images. We examine the impacts of CTE losses and outline some techniques to mitigate CTE effects during and after observation by use of post-flash and pixel-based CTE corrections. Finally, we summarize an investigation of WFC3/UVIS Point Spread Functions (PSFs) and their potential use for characterizing the focus of the instrument.

  18. A precise method to determine the activity of a weak neutron source using a germanium detector

    E-print Network

    M. J. M. Duke; A. L. Hallin; C. B. Krauss; P. Mekarski; L. Sibley

    2015-06-17

    A standard high purity germanium detector (HPGe) was used to determine the neutron activity of a weak americium-beryllium (AmBe) neutron source. Gamma rays were created through 27Al(n,n'), 27Al(n,gamma) and 1H(n,gamma) reactions induced by the neutrons on aluminum and acrylic disks. A Monte Carlo simulation was developed to model the efficiency of the detector system. The activity of our neutron source was determined to be 305.6 +/- 4.9 n/s. The result is consistent for the different gamma rays and was verified using additional simulations and measurements of the 4483 keV gamma ray produced directly from the AmBe source.

  19. A precise method to determine the activity of a weak neutron source using a germanium detector

    E-print Network

    Duke, M J M; Krauss, C B; Mekarski, P; Sibley, L

    2015-01-01

    A standard high purity germanium detector (HPGe) was used to determine the neutron activity of a weak americium-beryllium (AmBe) neutron source. Gamma rays were created through 27Al(n,n'), 27Al(n,gamma) and 1H(n,gamma) reactions induced by the neutrons on aluminum and acrylic disks. A Monte Carlo simulation was developed to model the efficiency of the detector system. The activity of our neutron source was determined to be 305.6 +/- 4.9 n/s. The result is consistent for the different gamma rays and was verified using additional simulations and measurements of the 4483 keV gamma ray produced directly from the AmBe source.

  20. High-purity germanium detector ionization pulse shapes of nuclear recoils, gamma interactions and microphonism

    E-print Network

    L. Baudis; J. Hellmig; H. V. Klapdor-Kleingrothaus; Y. Ramachers; J. W. Hammer; A. Mayer

    1999-01-19

    Nuclear recoil measurements with high-purity Germanium detectors are very promising to directly detect dark matter candidates. The main background sources in such experiments are natural radioactivity and microphonic noise. Digital pulse shape analysis is an encouraging approach to reduce the background originating from the latter. To study the pulse shapes of nuclear recoil events we performed a neutron scattering experiment, which covered the ionization energy range from 20 to 80 keV. We have measured ionization efficiencies as well and found an excellent agreement with the theory of Lindhard. In a further experiment we measured pulse shapes of a radioactive gamma-source and found no difference to nuclear recoil pulse shapes. Pulse shapes originating from microphonics of a HPGe-detector are presented for the first time. A microphonic noise suppression method, crucial for dark matter direct detection experiments, can therefore be calibrated with pulse shapes from gamma-sources.

  1. High quantum efficiency megavoltage imaging with thick scintillator detectors for image guided radiation therapy

    NASA Astrophysics Data System (ADS)

    Gopal, Arun

    In image guided radiation therapy (IGRT), imaging devices serve as guidance systems to aid patient set-up and tumor volume localization. Traditionally, 2-D megavoltage x-ray imagers, referred to as electronic portal imaging devices (EPIDs), have been used for planar target localization, and have recently been extended to perform 3-D volumetric reconstruction via cone-beam computed tomography (CBCT). However, current EPIDs utilize thin and inefficient phosphor screen detectors and are subsequently limited by poor soft tissue visualization, which limits their use for CBCT. Therefore, the use of thick scintillation media as megavoltage x-ray detectors for greater x-ray sensitivity and enhanced image quality has recently been of significant interest. In this research, two candidates for thick scintillators: CsI(Tl) and terbium doped scintillation glass were investigated in separate imaging configurations. In the first configuration, a thick scintillation crystal (TSC) consisting of a thick, monolithic slab of CsI(Tl) was coupled to a mirror-lens-camera system. The second configuration is based on a fiber-optic scintillation glass array (FOSGA), wherein the scintillation glass is drawn into long fiber-optic conduits, inserted into a grid-type housing constructed out of polymer-tungsten alloy, and coupled to an array of photodiodes for digital read-out. The imaging prototypes were characterized using theoretical studies and imaging measurements to obtain fundamental metrics of imaging performance. Spatial resolution was measured based on a modulation transfer function (MTF), noise was evaluated in terms of a noise power spectrum (NPS), and overall contrast was characterized in the form of detective quantum efficiency (DQE). The imaging studies were used to optimize the TSC and FOSGA imagers and propose prototype configurations for order-of-magnitude improvements in overall image quality. In addition, a fast and simple technique was developed to measure the MTF, NPS, and DQE metrics for clinical EPID and CBCT systems based on a novel adaptation of a traditional line-pair resolution bar-pattern. This research provides two significant benefits to radiotherapy: the characterization of a new generation of thick scintillator based megavoltage x-ray imagers for CBCT based IGRT, and the novel adaptation of fundamental imaging metrics from imaging research to routine clinical performance monitoring.

  2. Monte Carlo simulation of the BEGe detector response function for in vivo measurements of 241Am in the skull

    NASA Astrophysics Data System (ADS)

    Fantínová, K.; Fojtík, P.

    2014-11-01

    This paper reports on the procedure of the BEGe detector characterization for the Monte Carlo calibrations. A project is under way to improve the counting and operating capabilities of the Whole Body Counter (WBC) installed in SÚRO, v.v.i. (NRPI) Prague, Czech Republic. Possible emergency monitoring should mainly benefit from the rapid, safe and flexible operation of the WBC. The system of the WBC for the detection of low energy X and gamma radiation comprises four HPGe detectors intended for the routine, emergency, and research measurements of persons internally contaminated with low-energy photon emitters, mainly actinides. Among them, 241Am is the main subject of interest. A precise detection efficiency calibration of the detector is required for the measurement of activity in individual organs and tissues. The use of physical phantoms in the calibrations is often supplemented with the application of voxel phantoms and a Monte Carlo technique that are used for the calculation of the detector response function and the full energy peak efficiency. Both experimental and computational approaches have been used for the calibration of the BEGe (Broad Energy Germanium) detector. In this paper, the process of the Monte Carlo simulation of the detector response function and the peak efficiency calculation is described. Results of the simulations are provided in the paper and discussed.

  3. Calculation of the absolute detection efficiency of a moderated /sup 235/U neutron detector on the Tokamak Fusion Test Reactor

    SciTech Connect

    Ku, L.P.; Hendel, H.W.; Liew, S.L.

    1989-02-01

    Neutron transport simulations have been carried out to calculate the absolute detection efficiency of a moderated /sup 235/U neutron detector which is used on the TFTR as a part of the primary fission detector diagnostic system for measuring fusion power yields. Transport simulations provide a means by which the effects of variations in various shielding and geometrical parameters can be explored. These effects are difficult to study in calibration experiments. The calculational model, benchmarked against measurements, can be used to complement future detector calibrations, when the high level of radioactivity resulting from machine operation may severely restrict access to the tokamak. We present a coupled forward-adjoint algorithm, employing both the deterministic and Monte Carlo sampling methods, to model the neutron transport in the complex tokamak and detector geometries. Sensitivities of the detector response to the major and minor radii, and angular anisotropy of the neutron emission are discussed. A semi-empirical model based on matching the calculational results with a small set of experiments produces good agreement (+-15%) for a wide range of source energies and geometries. 20 refs., 6 figs., 4 tabs.

  4. Self-powered micro-structured solid state neutron detector with very low leakage current and high efficiency

    SciTech Connect

    Dahal, R.; Huang, K. C.; LiCausi, N.; Lu, J.-Q.; Bhat, I.; Clinton, J.; Danon, Y.

    2012-06-11

    We report on the design, fabrication, and performance of solid-state neutron detector based on three-dimensional honeycomb-like silicon micro-structures. The fabricated detectors use boron filled deep holes with aspect ratio of over 12 and showed a very low leakage current density of {approx}7 Multiplication-Sign 10{sup -7} A/cm{sup 2} at -1 V for device sizes varying from 2 Multiplication-Sign 2 to 5 Multiplication-Sign 5 mm{sup 2}. A thermal neutron detection efficiency of 4.5% {+-} 0.5% with discrimination setting of 500 keV and gamma to neutron sensitivity of (1.1 {+-} 0.1) Multiplication-Sign 10{sup -5} for single layer was measured without external bias for these devices. Monte-Carlo simulation predicts a maximum efficiency of 45% for such devices filled with 95% enriched {sup 10}boron.

  5. High efficiency and rapid response superconducting NbN nanowire single photon detector based on asymmetric split ring metamaterial

    SciTech Connect

    Li, Guanhai; Chen, Xiaoshuang; Wang, Shao-Wei Lu, Wei

    2014-06-09

    With asymmetric split ring metamaterial periodically placed on top of the niobium nitride (NbN) nanowire meander, we theoretically propose a kind of metal-insulator-metallic metamaterial nanocavity to enhance absorbing efficiency and shorten response time of the superconducting NbN nanowire single photon detector (SNSPD) operating at wavelength of 1550?nm. Up to 99.6% of the energy is absorbed and 96.5% dissipated in the nanowire. Meanwhile, taking advantage of this high efficiency absorbing cavity, we implement a more sparse arrangement of the NbN nanowire of the filling factor 0.2, which significantly lessens the nanowire and crucially boosts the response time to be only 40% of reset time in previous evenly spaced meander design. Together with trapped mode resonance, a standing wave oscillation mechanism is presented to explain the high efficiency and broad bandwidth properties. To further demonstrate the advantages of the nanocavity, a four-pixel SNSPD on 10??m?×?10??m area is designed to further reduce 75% reset time while maintaining 70% absorbing efficiency. Utilizing the asymmetric split ring metamaterial, we show a higher efficiency and more rapid response SNSPD configuration to contribute to the development of single photon detectors.

  6. High-efficiency superconducting nanowire single-photon detectors fabricated from MoSi thin-films

    E-print Network

    Verma, V B; Bussičres, F; Horansky, R D; Dyer, S D; Lita, A E; Vayshenker, I; Marsili, F; Shaw, M D; Zbinden, H; Mirin, R P; Nam, S W

    2015-01-01

    We demonstrate high-efficiency superconducting nanowire single-photon detectors (SNSPDs) fabricated from MoSi thin-films. We measure a maximum system detection efficiency (SDE) of 87 +- 0.5 % at 1542 nm at a temperature of 0.7 K, with a jitter of 76 ps, maximum count rate approaching 10 MHz, and polarization dependence as low as 3.4 +- 0.7 % The SDE curves show saturation of the internal efficiency similar to WSi-based SNSPDs at temperatures as high as 2.3 K. We show that at similar cryogenic temperatures, MoSi SNSPDs achieve efficiencies comparable to WSi-based SNSPDs with nearly a factor of two reduction in jitter.

  7. Development of a portable instrument for automated measurements of the detective quantum efficiency of x-ray detectors

    NASA Astrophysics Data System (ADS)

    Cunningham, I. A.; Lazarev, S.; Sattarivand, M.; Jankovic, N. D.

    2007-03-01

    The scientific community has generally adopted use of the modulation transfer function (MTF) and detective quantum efficiency (DQE) as primary measures of performance of radiographic detectors. However, measurement of these parameters is generally restricted to experts in laboratory environments due to the required x-ray physics knowledge, specialized instrumentation and computational analyses. We have developed a prototype instrument that automates both the physical measurement and subsequent image analysis to determine the MTF, noise power spectrum (NPS) and DQE of radiographic and mammographic systems. The instrument is placed in the x-ray path directly in front of the detector. A series of images are acquired, saved in "raw" DICOM format and then used to determine the MTF (using the slanted-edge method) and NPS. The number of incident quanta is calculated from measurements of the incident exposure including corrections for air temperature and pressure and ionization chamber spectral response. The primary sources of error are backscatter from the detector and scatter generated within the instrument. These have been minimized to achieve an incident exposure measurement within 2% of a calibrated electrometer and chamber in free space. The MTF and DQE of a commercial CsI-based flat-panel detector were measured over a range of incident exposures from 20 uR to 20 mR per image. Results agreed with both our own laboratory measurements and previously published measurements performed elsewhere with a similar detector within 2% for the MTF and 5% for the DQE. A complete DQE analysis of a clinical digital flat-panel detector is completed in 30 minutes and requires no system modifications.

  8. Using surface plasmons to enhance the speed and efficiency of superconducting nanowire single-photon detectors

    E-print Network

    Hu, Xiaolong

    We report our design and fabrication of superconducting nanowire single-photon detectors integrated with gold plasmonic nanostructures, which can enhance the absorption of TM-polarized light, and can enlarge the effective ...

  9. Simulation study comparing high-purity germanium and cadmium zinc telluride detectors for breast imaging

    PubMed Central

    Campbell, DL; Peterson, TE

    2014-01-01

    We conducted simulations to compare the potential imaging performance for breast cancer detection with High-Purity Germanium (HPGe) and Cadmium Zinc Telluride (CZT) systems with 1% and 3.8% energy resolution at 140 keV, respectively. Using the Monte Carlo N-Particle (MCNP5) simulation package, we modelled both 5 mm-thick CZT and 10 mm-thick HPGe detectors with the same parallel-hole collimator for the imaging of a breast/torso phantom. Simulated energy spectra were generated, and planar images were created for various energy windows around the 140-keV photopeak. Relative sensitivity and scatter and the torso fractions were calculated along with tumour contrast and signal-to-noise ratios (SNR). Simulations showed that utilizing a ą1.25% energy window with an HPGe system better suppressed torso background and small-angle scattered photons than a comparable CZT system using a ?5%/+10% energy window. Both systems provided statistically similar contrast and SNR, with HPGe providing higher relative sensitivity. Lowering the counts of HPGe images to match CZT count density still yielded equivalent contrast between HPGe and CZT. Thus, an HPGe system may provide equivalent breast imaging capability at lower injected radioactivity levels when acquiring for equal imaging time. PMID:25360792

  10. Simulation study comparing high-purity germanium and cadmium zinc telluride detectors for breast imaging

    NASA Astrophysics Data System (ADS)

    Campbell, D. L.; Peterson, T. E.

    2014-11-01

    We conducted simulations to compare the potential imaging performance for breast cancer detection with High-Purity Germanium (HPGe) and Cadmium Zinc Telluride (CZT) systems with 1% and 3.8% energy resolution at 140?keV, respectively. Using the Monte Carlo N-Particle (MCNP5) simulation package, we modelled both 5?mm-thick CZT and 10?mm-thick HPGe detectors with the same parallel-hole collimator for the imaging of a breast/torso phantom. Simulated energy spectra were generated, and planar images were created for various energy windows around the 140?keV photopeak. Relative sensitivity and scatter and the torso fractions were calculated along with tumour contrast and signal-to-noise ratios (SNR). Simulations showed that utilizing a ą1.25% energy window with an HPGe system better suppressed torso background and small-angle scattered photons than a comparable CZT system using a -5%/+10% energy window. Both systems provided statistically similar contrast and SNR, with HPGe providing higher relative sensitivity. Lowering the counts of HPGe images to match CZT count density still yielded equivalent contrast between HPGe and CZT. Thus, an HPGe system may provide equivalent breast imaging capability at lower injected radioactivity levels when acquiring for equal imaging time.

  11. A detector module with highly efficient surface-alpha event rejection operated in CRESST-II Phase 2

    NASA Astrophysics Data System (ADS)

    Strauss, R.; Angloher, G.; Bento, A.; Bucci, C.; Canonica, L.; Erb, A.; von Feilitzsch, F.; Ferreiro, N.; Gorla, P.; Gütlein, A.; Hauff, D.; Jochum, J.; Kiefer, M.; Kluck, H.; Kraus, H.; Lanfranchi, J.-C.; Loebell, J.; Münster, A.; Petricca, F.; Potzel, W.; Pröbst, F.; Reindl, F.; Roth, S.; Rottler, K.; Sailer, C.; Schäffner, K.; Schieck, J.; Scholl, S.; Schönert, S.; Seidel, W.; von Sivers, M.; Stanger, M.; Stodolsky, L.; Strandhagen, C.; Tanzke, A.; Uffinger, M.; Ulrich, A.; Usherov, I.; Wawoczny, S.; Willers, M.; Wüstrich, M.; Zöller, A.

    2015-08-01

    The cryogenic dark matter experiment CRESST-II aims at the direct detection of WIMPs via elastic scattering off nuclei in scintillating CaWO crystals. We present a new, highly improved, detector design installed in the current run of CRESST-II Phase 2 with an efficient active rejection of surface-alpha backgrounds. Using CaWO sticks instead of metal clamps to hold the target crystal, a detector housing with fully-scintillating inner surface could be realized. The presented detector (TUM40) provides an excellent threshold of keV and a resolution of keV (at 2.60 keV). With significantly reduced background levels, TUM40 sets stringent limits on the spin-independent WIMP-nucleon scattering cross section and probes a new region of parameter space for WIMP masses below 3 GeV/c. In this paper, we discuss the novel detector design and the surface-alpha event rejection in detail.

  12. Free-running InGaAs single photon detector with 1 dark count per second at 10% efficiency

    E-print Network

    Boris Korzh; Nino Walenta; Tommaso Lunghi; Nicolas Gisin; Hugo Zbinden

    2014-12-03

    We present a free-running single photon detector for telecom wavelengths based on a negative feedback avalanche photodiode (NFAD). A dark count rate as low as 1 cps was obtained at a detection efficiency of 10%, with an afterpulse probability of 2.2% for 20 {\\mu}s of deadtime. This was achieved by using an active hold-off circuit and cooling the NFAD with a free-piston stirling cooler down to temperatures of -110${^o}$C. We integrated two detectors into a practical, 625 MHz clocked quantum key distribution system. Stable, real-time key distribution in presence of 30 dB channel loss was possible, yielding a secret key rate of 350 bps.

  13. Free-running InGaAs single photon detector with 1 dark count per second at 10% efficiency

    SciTech Connect

    Korzh, B. Walenta, N.; Lunghi, T.; Gisin, N.; Zbinden, H.

    2014-02-24

    We present a free-running single photon detector for telecom wavelengths based on a negative feedback avalanche photodiode (NFAD). A dark count rate as low as 1?cps was obtained at a detection efficiency of 10%, with an afterpulse probability of 2.2% for 20??s of deadtime. This was achieved by using an active hold-off circuit and cooling the NFAD with a free-piston stirling cooler down to temperatures of ?110?°C. We integrated two detectors into a practical, 625?MHz clocked quantum key distribution system. Stable, real-time key distribution in the presence of 30?dB channel loss was possible, yielding a secret key rate of 350?bps.

  14. Improvements in the Low Energy Collection Efficiency of Si(Li) X-ray Detectors

    SciTech Connect

    Cox,C.; Fischer, D.; Schwartz, W.; Song, Y.

    2005-01-01

    Soft X-ray beam-line applications are of fundamental importance to material research, and commonly employ high-resolution Si(Li) detectors for energy dispersive spectroscopy. However, the measurement of X-rays below 1 keV is compromised by absorption in the material layers in front of the active crystal and a dead layer at the crystal surface. Various Schottky barrier type contacts were investigated resulting in a 40% reduction of the dead-layer thickness and a factor of two increased sensitivity at carbon K{sub {alpha}} compared to the standard Si(Li) detector. Si(Li) detectors were tested on the U7A soft X-ray beam-line at the National Synchrotron Light Source and on a scanning electron microscope (SEM).

  15. Search for rare nuclear decays with HPGe detectors at the STELLA facility of the LNGS

    SciTech Connect

    Belli, P.; Di Marco, A.; Bernabei, R.; D'Angelo, S.; Cappella, F.; D'Angelo, A.; Incicchitti, A.; Cerulli, R.; Di Vacri, M. L.; Laubenstein, M.; Nisi, S.; Danevich, F. A.; Kobychev, V. V.; Poda, D. V.; Tretyak, V. I.; Kovtun, G. P.; Kovtun, N. G.; Shcherban, A. P.; Solopikhin, D. A.; Polischuk, O. G.; and others

    2013-12-30

    Results on the search for rare nuclear decays with the ultra low background facility STELLA at the LNGS using gamma ray spectrometry are presented. In particular, the best T{sub 1/2} limits were obtained for double beta processes in {sup 96}Ru and {sup 104}Ru. Several isotopes, which potentially decay through different 2? channels, including also possible resonant double electron captures, were investigated for the first time ({sup 156}Dy, {sup 158}Dy, {sup 184}Os, {sup 192}Os, {sup 190}Pt, {sup 198}Pt). Search for resonant absorption of solar {sup 7}Li axions in a LiF crystal gave the best limit for the mass of {sup 7}Li axions (< 8.6 keV). Rare alpha decay of {sup 190}Pt to the first excited level of {sup 186}Os(E{sub exc}?=?137.2keV) was observed for the first time.

  16. Systematic Effects in Pulse Shape Analysis of HPGe Detector Signals for Neutrinoless Double-Beta Decay

    E-print Network

    Victor M Gehman; Steven R Elliott; Dongming Mei

    2010-03-05

    Pulse shape analysis is an important background reduction and signal identification technique for next generation of neutrinoless double-beta decay experiments examining 76Ge. We present a study of the systematic uncertainties in one such parametric pulse-shape analysis technique for separating multi-site backgrounds from single-site signal events. We examined systematic uncertainties for events in full-energy gamma peaks (predominantly multi-site), double escape peaks (predominantly single-site) and the Compton continuum near double-beta decay endpoint (which will be the dominant background for most neutrinoless double-beta decay searches). In short, we find total (statistical plus systematic) fractional uncertainties in the pulse shape cut survival probabilities of: 6.6%, 1.5% and 3.8% for double-escape, continuum and gamma-ray events respectively.

  17. Low ? activity measurement of meteorites using HPGe-NaI detector system

    NASA Astrophysics Data System (ADS)

    Colombetti, P.; Taricco, C.; Bhandari, N.; Sinha, N.; Di Martino, M.; Cora, A.; Vivaldo, G.

    2013-08-01

    The radioactivity in natural samples like cosmogenic isotopes in meteorites, in Moon samples, in earth and ice in Antarctica, produced by protons, neutrons, ? mesons and other charged particles, is very low, usually below 0.001 disintegration per minute per gram. Therefore, very special techniques are required, particularly if the sample cannot be destroyed for chemical separation and system must have possibility of counting large amount of sample. For this purpose we have developed a highly selective Ge-NaI coincidence spectrometer, operating in the underground Laboratory of Monte dei Cappuccini (INAF) in Torino. We have then improved it by developing a multiparametric acquisition system, which allows better selectivity of the coincidence windows (e.g., in meteorites, to disentangle cosmogenic 44Ti signal from overlapping 214Bi, originated by naturally occurring 238U). Applications of this system to the study of meteorites (chondrite, achondrite and iron samples) are described.

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

    SciTech Connect

    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. Proton-induced radiation damage in germanium detectors

    SciTech Connect

    Bruckner, J.; Korfer, M.; Wanke, H. , Mainz ); Schroeder, A.N.F. ); Figes, D.; Dragovitsch, P. ); Englert, P.A.J. ); Starr, R.; Trombka, J.I. . Goddard Space Flight Center); Taylor, I. ); Drake, D.M.; Shunk, E.R. )

    1991-04-01

    High-purity germanium (HPGe) detectors will be used in future space missions for gamma-ray measurements and will be subject to interactions with energetic particles. To simulate this process several large-volume n-type HPGe detectors were incrementally exposed to a particle fluence of up to 10{sub 8} protons cm{sup {minus}2} (proton energy: 1.5 GeV) at different operating temperatures (90 to 120 K) to induce radiation damage. Basic scientific as well as engineering data on detector performance were collected. During the incremental irradiation, the peak shape produced by the detectors showed a significant change from a Gaussian shape to a broad complex structure. After the irradiation all detectors were thoroughly characterized by measuring many parameters. To remove the accumulated radiation damage the detectors were stepwise annealed at temperatures T {le} 110{degrees}C while staying specially designed cryostats. This paper shows that n-type HPGe detectors can be used in charged particles environments as high-energy resolution devices until a certain level of radiation damage is accumulated and that the damage can be removed at moderate annealing temperatures and the detector returned to operating condition.

  20. Signal and charge collection efficiency of n-in-p strip detectors after mixed irradiation to HL-LHC fluences

    NASA Astrophysics Data System (ADS)

    Kuehn, Susanne; Barber, Thomas; Casse, Gianluigi; Dervan, Paul; Driewer, Adrian; Forshaw, Dean; Huse, Torkjell; Jakobs, Karl; Parzefall, Ulrich

    2013-12-01

    For the year 2020, an upgrade of the LHC with a factor ten increase in luminosity is planned. The resulting severe radiation doses for the ATLAS tracker demand extremely radiation tolerant detectors. In this study six planar n-in-p strip sensors produced by Hamamatsu Photonics were irradiated in consecutive irradiation steps with pions of 280 Mev/c, protons of 25 Mev/c and reactor neutrons resulting in a combined fluence of up to 3×1015 1 MeV neutron equivalent particles per square centimeter (neq /cm2). This particle composition and fluence corresponds to the qualification limit specified by the ATLAS experiment for the outer pixel layers (assuming an integrated luminosity of 3000 fb-1). The 320 ?m thick devices are investigated using electrons from a 90Sr source. After each irradiation step both charge collection efficiency and noise measurements have been performed using the ALIBAVA readout system, which is based on analogue Beetle ASICs clocked at 40 MHz. Measurements of the signal and signal-to-noise ratio of detectors will be given after the sensors were exposed to radiation that both in fluence and composition are corresponding to the expectations for the HL-LHC trackers. Conclusions will be drawn on their operation in the ATLAS inner detector upgrade.

  1. Enhanced quantum efficiency of high-purity silicon imaging detectors by ultralow temperature surface modification using Sb doping

    NASA Technical Reports Server (NTRS)

    Blacksberg, Jordana; Hoenk, Michael E.; Elliott, S. Tom; Holland, Stephen E.; Nikzad, Shouleh

    2005-01-01

    A low temperature process for Sb doping of silicon has been developed as a backsurface treatment for high-purity n-type imaging detectors. Molecular beam epitaxy (MBE) is used to achieve very high dopant incorporation in a thin, surface-confined layer. The growth temperature is kept below 450 (deg)C for compatibility with Al-metallized devices. Imaging with MBE-modified 1kx1k charge coupled devices (CCDs) operated in full depletion has been demonstrated. Dark current is comparable to the state-of-the-art process, which requires a high temperature step. Quantum efficiency is improved, especially in the UV, for thin doped layers placed closer to the backsurface. Near 100% internal quantum efficiency has been demonstrated in the ultraviolet for a CCD with a 1.5 nm silicon cap layer.

  2. First demonstration of plasmonic GaN quantum cascade detectors with enhanced efficiency at normal incidence.

    PubMed

    Pesach, Asaf; Sakr, Salam; Giraud, Etienne; Sorias, Ofir; Gal, Lior; Tchernycheva, Maria; Orenstein, Meir; Grandjean, Nicolas; Julien, Francois H; Bahir, Gad

    2014-08-25

    We have designed, fabricated and measured the first plasmon-assisted normal incidence GaN/AlN quantum cascade detector (QCD) making use of the surface plasmon resonance of a two-dimensional nanohole Au array integrated on top of the detector absorption region. The spectral response of the detector at room temperature is peaked at the plasmon resonance of 1.82 ?m. We show that the presence of the nanohole array induces an absolute enhancement of the responsivity by a factor of ~30 over that of the bare device at normal incidence and by a factor of 3 with respect to illumination by the 45° polished side facet. We show that this significant improvement arises from two phenomena, namely, the polarization rotation of the impinging light from tangential to normal induced by the plasmonic structure and from the enhancement of the absorption cross-section per quantum well due to the near-field optical intensity of the plasmonic wave. PMID:25321307

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

    DOEpatents

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

    1989-01-01

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

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

    DOEpatents

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

    1987-02-27

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

  5. Automation of the Characterization of High Purity Germanium Detectors

    NASA Astrophysics Data System (ADS)

    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 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). Los Alamos National Laboratory and New Mexico Institute of Mining and Technology.

  6. Comparison of two methods for high purity germanium detector efficiency calibration for charcoal canister radon measurement.

    PubMed

    Nikolic, J; Pantelic, G; Zivanovic, M; Rajacic, M; Todorovic, D

    2014-11-01

    The charcoal canister method of radon measurement according to US Environment Protection Agency protocol 520/5-87-005 is widely used for screening. This method is based on radon adsorption on coal and measurement of gamma radiation of radon daughters. For the purpose of gamma spectrometry, appropriate efficiency calibration of the measuring system must be performed. The most usual method of calibration is using standard canister, a sealed canister with the same matrix and geometry as the canisters used for measurements, but with the known activity of radon. In the absence of standard canister, a different method of efficiency calibration has to be implemented. This study presents the results of efficiency calibration using the EFFTRAN efficiency transfer software. Efficiency was calculated using a soil matrix cylindrical secondary reference material as a starting point. Calculated efficiency is then compared with the one obtained using standard canister and applied to a realistic measurement in order to evaluate the results of the efficiency transfer. PMID:25377751

  7. Calibration Analyses and Efficiency Studies for the Anti Coincidence Detector on the Fermi Gamma Ray Space Telescope

    SciTech Connect

    Kachulis, Chris; /Yale U. /SLAC

    2011-06-22

    The Anti Coincidence Detector (ACD) on the Fermi Gamma Ray Space Telescope provides charged particle rejection for the Large Area Telescope (LAT). We use two calibrations used by the ACD to conduct three studies on the performance of the ACD. We examine the trending of the calibrations to search for damage and find a timescale over which the calibrations can be considered reliable. We also calculated the number of photoelectrons counted by a PMT on the ACD from a normal proton. Third, we calculated the veto efficiencies of the ACD for two different veto settings. The trends of the calibrations exhibited no signs of damage, and indicated timescales of reliability for the calibrations of one to two years. The number of photoelectrons calculated ranged from 5 to 25. Large errors in the effect of the energy spectrum of the charged particles caused these values to have very large errors of around 60 percent. Finally, the veto efficiencies were found to be very high at both veto values, both for charged particles and for the lower energy backsplash spectrum. The Anti Coincidence Detector (ACD) on the Fermi Gamma Ray Space Telescope is a detector system built around the silicon strip tracker on the Large Area Telescope (LAT). The purpose of the ACD is to provide charged particle rejection for the LAT. To do this, the ACD must be calibrated correctly in flight, and must be able to efficiently veto charged particle events while minimizing false vetoes due to 'backsplash' from photons in the calorimeter. There are eleven calibrations used by the ACD. In this paper, we discuss the use of two of these calibrations to preform three studies on the performance of the ACD. The first study examines trending of the calibrations to check for possible hardware degradation. The second study uses the calibrations to explore the efficiency of an on-board hardware veto. The third study uses the calibrations to calculate the number of photoelectrons seen by each PMT when a minimum ionizing particle is detected, which is a useful value for performing simulations.

  8. A DC-coupling area-efficiency readout circuit for CdZnTe detectors

    NASA Astrophysics Data System (ADS)

    Wang, J.; Su, L.; Wei, X.; Zheng, R.; Hu, Y.

    2015-09-01

    In this paper, a DC-coupling readout circuit is presented in order to readout the signal from CdZnTe detectors. A differential stage is added in CSA to compensate the leakage current introduced by the CdZnTe crystal. A compact shaper is designed to achieve low area with wide range of adjustable peaking time from 3 ? s to 10 ? s. The area of proposed circuit is about 130 ? m × 1100 ? m. The experimental results show that the ENC is 70 e- + 14 e-/pF and the gain is about 152 mV/fC at the peaking time of 4 ? s.

  9. Neutron Damage in Mechanically-Cooled High-Purity Germanium Detectors for Field-Portable Prompt Gamma Neutron Activation Analysis (PGNAA) Systems

    SciTech Connect

    E.H. Seabury; C.J. Wharton; A.J. Caffrey; J.B. McCabe; C. DeW. Van Siclen

    2013-10-01

    Prompt Gamma Neutron Activation (PGNAA) systems require the use of a gamma-ray spectrometer to record the gamma-ray spectrum of an object under test and allow the determination of the object’s composition. Field-portable systems, such as Idaho National Laboratory’s PINS system, have used standard liquid-nitrogen-cooled high-purity germanium (HPGe) detectors to perform this function. These detectors have performed very well in the past, but the requirement of liquid-nitrogen cooling limits their use to areas where liquid nitrogen is readily available or produced on-site. Also, having a relatively large volume of liquid nitrogen close to the detector can impact some assessments, possibly leading to a false detection of explosives or other nitrogen-containing chemical. Use of a mechanically-cooled HPGe detector is therefore very attractive for PGNAA applications where nitrogen detection is critical or where liquid-nitrogen logistics are problematic. Mechanically-cooled HPGe detectors constructed from p-type germanium, such as Ortec’s trans-SPEC, have been commercially available for several years. In order to assess whether these detectors would be suitable for use in a fielded PGNAA system, Idaho National Laboratory (INL) has been performing a number of tests of the resistance of mechanically-cooled HPGe detectors to neutron damage. These detectors have been standard commercially-available p-type HPGe detectors as well as prototype n-type HPGe detectors. These tests compare the performance of these different detector types as a function of crystal temperature and incident neutron fluence on the crystal.

  10. Spatial resolution and efficiency of microchannel plate detectors with neutron converter films

    NASA Astrophysics Data System (ADS)

    Cazalas, Edward; Trivelpiece, Cory; Jovanovic, Igor

    2014-12-01

    An investigation into the potential neutron detection efficiency gains that could be made to microchannel plates (MCPs) has been conducted by a GEANT4 simulation. Thin-film neutron converters are coupled to the upstream-side of the MCP. MCPs with and without pre-existing neutron sensitivity were examined. A study into potential film materials favors a Gd2O3 converter film utilized in thin-film and pillar geometries for straight-channel MCPs. The objective was to increase thermal neutron detection efficiency without sacrificing the spatial resolution of the system by studying (1) the balance between capture efficiency and charged particle product production and range to optimize detection efficiency, and (2) the extent of radial straggling that the reaction products undergo as they are transmitted through the neutron converter and MCP, which affects spatial resolution. Our investigation reveals that an increase in efficiency of 9.9% can be achieved for an MCP without preexisting neutron sensitivity using a film geometry neutron converter of 4-?m thickness. An increase in efficiency of 4.3% can be achieved for a neutron-sensitive MCP using a pillar-type converter of 4-?m thickness. Degradation of spatial resolution is not significant for either film or pillar geometries with thicknesses in the range 0.5-10 ?m.

  11. Approaching the Ultimate Limits of Communication Efficiency with a Photon-Counting Detector

    NASA Technical Reports Server (NTRS)

    Erkmen, Baris; Moision, Bruce; Dolinar, Samuel J.; Birnbaum, Kevin M.; Divsalar, Dariush

    2012-01-01

    Coherent states achieve the Holevo capacity of a pure-loss channel when paired with an optimal measurement, but a physical realization of this measurement is as of yet unknown, and it is also likely to be of high complexity. In this paper, we focus on the photon-counting measurement and study the photon and dimensional efficiencies attainable with modulations over classical- and nonclassical-state alphabets. We first review the state-of-the-art coherent on-off-keying (OOK) with a photoncounting measurement, illustrating its asymptotic inefficiency relative to the Holevo limit. We show that a commonly made Poisson approximation in thermal noise leads to unbounded photon information efficiencies, violating the conjectured Holevo limit. We analyze two binary-modulation architectures that improve upon the dimensional versus photon efficiency tradeoff achievable with conventional OOK. We show that at high photon efficiency these architectures achieve an efficiency tradeoff that differs from the best possible tradeoff--determined by the Holevo capacity--by only a constant factor. The first architecture we analyze is a coherent-state transmitter that relies on feedback from the receiver to control the transmitted energy. The second architecture uses a single-photon number-state source.

  12. Quantitative Analysis and Efficiency Study of PSD Methods for a LaBr3:Ce Detector

    E-print Network

    Ming Zeng; Jirong Cang; Zhi Zeng; Xiaoguang Yue; Jianping Cheng; Yinong Liu; Junli Li

    2015-08-17

    The LaBr3:Ce scintillator has been widely studied for nuclear spectroscopy because of its optimal energy resolution (algorithm parameters and discrimination efficiency are calculated for each method. Moreover, for the CCM, the correlation between the CCM feature value distribution and the total charge (energy) is studied, and a fitting equation for the correlation is inferred and experimentally verified. Using the equations, an energy-dependent threshold can be chosen to optimize the discrimination efficiency. Additionally, the experimental results show a potential application in low-activity high-energy {\\gamma} measurement by suppressing the alpha background.

  13. Improving photon detector efficiency using a high-fidelity optical controlled-not gate

    NASA Astrophysics Data System (ADS)

    Brown, Katherine L.; Singh, Robinjeet; Plaskus, Joshua H. Mendez; Broadus, Hanna E.; Dowling, Jonathan P.

    2015-02-01

    A significant problem for optical quantum computing is inefficient or inaccurate photodetectors. It is possible to use controlled-not (cnot) gates to improve a detector by making a large cat state, then measuring every qubit in that state. In this paper we develop a code that compares five different schemes for making multiple measurements, some of which are capable of detecting loss and some of which are not. We explore how each of these schemes performs in the presence of different errors, and derive a formula to find at what probability of qubit loss it is worth detecting loss, and at what probability does this just lead to further errors than the loss introduces.

  14. Patient-dependent count-rate adaptive normalization for PET detector efficiency with delayed-window coincidence events

    NASA Astrophysics Data System (ADS)

    Niu, Xiaofeng; Ye, Hongwei; Xia, Ting; Asma, Evren; Winkler, Mark; Gagnon, Daniel; Wang, Wenli

    2015-07-01

    Quantitative PET imaging is widely used in clinical diagnosis in oncology and neuroimaging. Accurate normalization correction for the efficiency of each line-of- response is essential for accurate quantitative PET image reconstruction. In this paper, we propose a normalization calibration method by using the delayed-window coincidence events from the scanning phantom or patient. The proposed method could dramatically reduce the ‘ring’ artifacts caused by mismatched system count-rates between the calibration and phantom/patient datasets. Moreover, a modified algorithm for mean detector efficiency estimation is proposed, which could generate crystal efficiency maps with more uniform variance. Both phantom and real patient datasets are used for evaluation. The results show that the proposed method could lead to better uniformity in reconstructed images by removing ring artifacts, and more uniform axial variance profiles, especially around the axial edge slices of the scanner. The proposed method also has the potential benefit to simplify the normalization calibration procedure, since the calibration can be performed using the on-the-fly acquired delayed-window dataset.

  15. High quantum efficiency and low dark count rate in multi-layer superconducting nanowire single-photon detectors

    SciTech Connect

    Jafari Salim, A. Eftekharian, A.; Hamed Majedi, A.

    2014-02-07

    In this paper, we theoretically show that a multi-layer superconducting nanowire single-photon detector (SNSPD) is capable of approaching characteristics of an ideal SNSPD in terms of the quantum efficiency, dark count, and band-width. A multi-layer structure improves the performance in two ways. First, the potential barrier for thermally activated vortex crossing, which is the major source of dark counts and the reduction of the critical current in SNSPDs is elevated. In a multi-layer SNSPD, a vortex is made of 2D-pancake vortices that form a stack. It will be shown that the stack of pancake vortices effectively experiences a larger potential barrier compared to a vortex in a single-layer SNSPD. This leads to an increase in the experimental critical current as well as significant decrease in the dark count rate. In consequence, an increase in the quantum efficiency for photons of the same energy or an increase in the sensitivity to photons of lower energy is achieved. Second, a multi-layer structure improves the efficiency of single-photon absorption by increasing the effective optical thickness without compromising the single-photon sensitivity.

  16. The detective quantum efficiency of photon-counting x-ray detectors using cascaded-systems analyses

    SciTech Connect

    Tanguay, Jesse; Yun, Seungman; Kim, Ho Kyung; Cunningham, Ian A.

    2013-04-15

    Purpose: Single-photon counting (SPC) x-ray imaging has the potential to improve image quality and enable new advanced energy-dependent methods. The purpose of this study is to extend cascaded-systems analyses (CSA) to the description of image quality and the detective quantum efficiency (DQE) of SPC systems. Methods: Point-process theory is used to develop a method of propagating the mean signal and Wiener noise-power spectrum through a thresholding stage (required to identify x-ray interaction events). The new transfer relationships are used to describe the zero-frequency DQE of a hypothetical SPC detector including the effects of stochastic conversion of incident photons to secondary quanta, secondary quantum sinks, additive noise, and threshold level. Theoretical results are compared with Monte Carlo calculations assuming the same detector model. Results: Under certain conditions, the CSA approach can be applied to SPC systems with the additional requirement of propagating the probability density function describing the total number of image-forming quanta through each stage of a cascaded model. Theoretical results including DQE show excellent agreement with Monte Carlo calculations under all conditions considered. Conclusions: Application of the CSA method shows that false counts due to additive electronic noise results in both a nonlinear image signal and increased image noise. There is a window of allowable threshold values to achieve a high DQE that depends on conversion gain, secondary quantum sinks, and additive noise.

  17. Normalization in 3D PET: Comparison of Detector Efficiencies Obtained from Uniform Planar and Cylindrical Sources

    E-print Network

    Oakes, Terry

    and Cylindrical Sources T.R.Oakes, V.Sossi, and T.J.Ruth University of British Columbia/TRIUMF PET Centre 4004 Normalization Factors (NFs) obtained from a uniform planar source and a uniform cylindrical phantom. The NFs-scattering planar distribution. NFs derived from 3D planar and 3D cylindrical efficiency data were applied

  18. Characterization measurement of a thick CdTe detector for BNCT-SPECT - detection efficiency and energy resolution.

    PubMed

    Murata, Isao; Nakamura, Soichiro; Manabe, Masanobu; Miyamaru, Hiroyuki; Kato, Itsuro

    2014-06-01

    Author?s group is carrying out development of BNCT-SPECT with CdTe device, which monitors the therapy effect of BNCT in real-time. From the design calculations, the dimensions were fixed to 1.5×2×30mm(3). For the collimator it was confirmed that it would have a good spatial resolution and simultaneously the number of counts would be acceptably large. After producing the CdTe crystal, the characterization measurement was carried out. For the detection efficiency an excellent agreement between calculation and measurement was obtained. Also, the detector has a very good energy resolution so that gamma-rays of 478keV and 511keV could be distinguished in the spectrum. PMID:24581600

  19. The effect of the displacement damage on the Charge Collection Efficiency in Silicon Drift Detectors for the LOFT satellite

    E-print Network

    Del Monte, E; Bozzo, E; Cadoux, F; Rachevski, A; Zampa, G; Zampa, N; Feroci, M; Pohl, M; Vacchi, A

    2015-01-01

    The technology of Silicon Drift Detectors (SDDs) has been selected for the two instruments aboard the Large Observatory For X-ray Timing (LOFT) space mission. LOFT underwent a three year long assessment phase as candidate for the M3 launch opportunity within the "Cosmic Vision 2015 -- 2025" long-term science plan of the European Space Agency. During the LOFT assessment phase, we studied the displacement damage produced in the SDDs by the protons trapped in the Earth's magnetosphere. In a previous paper we discussed the effects of the Non Ionising Energy Losses from protons on the SDD leakage current. In this paper we report the measurement of the variation of Charge Collection Efficiency produced by displacement damage caused by protons and the comparison with the expected damage in orbit.

  20. Fabrication of multi-layered absorption structure for high quantum efficiency photon detectors

    SciTech Connect

    Fujii, Go; Fukuda, Daiji; Numata, Takayuki; Yoshizawa, Akio; Tsuchida, Hidemi; Fujino, Hidetoshi; Ishii, Hiroyuki; Itatani, Taro; Zama, Tatsuya; Inoue, Shuichiro

    2009-12-16

    We report on some efforts to improve a quantum efficiency of titanium-based optical superconducting transition edge sensors using the multi-layered absorption structure for maximizing photon absorption in the Ti layer. Using complex refractive index values of each film measured by a Spectroscopic Ellipsometry, we designed and optimized by a simulation code. An absorption measurement of fabricated structure was in good agreement with the design and was higher than 99% at optimized wavelength of 1550 nm.

  1. Development of a CZT drift ring detector for X and ? ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Alruhaili, A.; Sellin, P. J.; Lohstroh, A.; Boothman, V.; Veeramani, P.; Veale, M. C.; Sawhney, K. J. S.; Kachkanov, V.

    2015-04-01

    CdTe and CZT detectors are considered better choices for high energy ? and X-ray spectroscopy in comparison to Si and HPGe detectors due to their good quantum efficiency and room temperature operation. The performance limitations in CdTe and CZT detectors are mainly associated with poor hole transport and trapping phenomena. Among many techniques that can be used to eliminate the effect of the poor charge transport properties of holes in CdTe and CZT material, the drift ring technique shows promising results. In this work, the performance of a 2.3 mm thick CZT drift ring detector is investigated. Spatially resolved measurements were carried out with an X-ray microbeam (25 and 75 keV) at the Diamond Light Source synchrotron to study the response uniformity and extent of the active area. Higher energy photon irradiation was also carried out at up to 662 keV using different radioisotopes to complement the microbeam data. Different biasing schemes were investigated in terms of biasing the cathode rear electrode (bulk field) and the ring electrodes (lateral fields). The results show that increasing the bulk field with fixed-ratio ring biases and lateral fields with fixed bulk fields increase the active area of the device significantly, which contrasts with previous studies in CdTe, where only an increasing lateral field resulted in an improvement of device performance. This difference is attributed to the larger thickness of the CZT device reported here.

  2. An efficient procedure for tomotherapy treatment plan verification using the on-board detector

    NASA Astrophysics Data System (ADS)

    Pisaturo, O.; Miéville, F.; Tercier, P.-A.; Allal, A. S.

    2015-02-01

    In this work, a fast and simple procedure for tomotherapy treatment plan verification using the on-board detector (OBD) has been developed. This procedure allows verification of plans with static and dynamic jaws (TomoEDGE). A convolution-based calculation model has been derived in order to link the leaf control sinogram from the treatment planning system to the data acquired by the OBD during a static couch procedure. The convolution kernel has been optimized using simple plans calculated in the Tomotherapy Cheese phantom. The optimal kernel has been found to be a lorentzian function, whose parameter ? is 0.186 for the 1 cm jaw opening, 0.232 for the 2.5 cm jaw opening and 0.373 for the 5 cm jaw opening. The evaluation has been performed with a ?-index analysis. The dose criterion was 3% of the 95th percentile of the dose distribution and the distance-to-agreement criterion is 2 mm. In order to validate the procedure, it has been applied to around 50 clinical treatment plans, which had already been validated by the Delta4 phantom (Scandidos, Sweden). 96% of the tested plans have passed the criteria. Concerning the other 4%, significant discrepancies between the leaf pattern in the leaf control sinogram and the OBD data have been shown, which might be due to differences in the leaf open time. This corresponds also to a higher sensitivity of this method over the Delta4, adding the possibility of better monitoring the treatment delivery.

  3. Large-area NbN superconducting nanowire avalanche photon detectors with saturated detection efficiency

    NASA Astrophysics Data System (ADS)

    Murphy, Ryan P.; Grein, Matthew E.; Gudmundsen, Theodore J.; McCaughan, Adam; Najafi, Faraz; Berggren, Karl K.; Marsili, Francesco; Dauler, Eric A.

    2015-05-01

    Superconducting circuits comprising SNSPDs placed in parallel—superconducting nanowire avalanche photodetectors, or SNAPs—have previously been demonstrated to improve the output signal-to-noise ratio (SNR) by increasing the critical current. In this work, we employ a 2-SNAP superconducting circuit with narrow (40 nm) niobium nitride (NbN) nanowires to improve the system detection efficiency to near-IR photons while maintaining high SNR. Additionally, while previous 2-SNAP demonstrations have added external choke inductance to stabilize the avalanching photocurrent, we show that the external inductance can be entirely folded into the active area by cascading 2-SNAP devices in series to produce a greatly increased active area. We fabricated series-2-SNAP (s2-SNAP) circuits with a nanowire length of 20 ?m with cascades of 2-SNAPs providing the choke inductance necessary for SNAP operation. We observed that (1) the detection efficiency saturated at high bias currents, and (2) the 40 nm 2-SNAP circuit critical current was approximately twice that for a 40 nm non-SNAP configuration.

  4. FOUR PI CALIBRATION AND MODELING OF A BARE GERMANIUM DETECTOR IN A CYLINDRICAL FIELD SOURCE

    SciTech Connect

    Dewberry, R.; Young, J.

    2011-04-29

    In reference 1 the authors described {gamma}-ray holdup assay of a Mossbauer spectroscopy instrument where they utilized two axial symmetric cylindrical shell acquisitions and two disk source acquisitions to determine Am-241 and Np-237 contamination. The measured contents of the two species were determined using a general detector efficiency calibration taken from a 12-inch point source.2 The authors corrected the raw spectra for container absorption as well as for geometry corrections to transform the calibration curve to the applicable axial symmetric cylindrical source - and disk source - of contamination. The authors derived the geometry corrections with exact calculus that are shown in equations (1) and (2) of our Experimental section. A cylindrical shell (oven source) acquisition configuration is described in reference 3, where the authors disclosed this configuration to gain improved sensitivity for holdup measure of U-235 in a ten-chamber oven. The oven was a piece of process equipment used in the Savannah River Plant M-Area Uranium Fuel Fabrication plant for which a U-235 holdup measurement was necessary for its decontamination and decommissioning in 2003.4 In reference 4 the authors calibrated a bare NaI detector for these U-235 holdup measurements. In references 5 and 6 the authors calibrated a bare HpGe detector in a cylindrical shell configuration for improved sensitivity measurements of U-235 in other M-Area process equipment. Sensitivity was vastly improved compared to a close field view of the sample, with detection efficiency of greater than 1% for the 185.7-keV {gamma}-ray from U-235. In none of references 3 - 7 did the authors resolve the exact calculus descriptions of the acquisition configurations. Only the empirical efficiency for detection of the 185.7-keV photon from U-235 decay was obtained. Not until the 2010 paper of reference 1 did the authors derive a good theoretical description of the flux of photons onto the front face of a detector from an axially symmetric cylindrical shell. Subsequent to publication of 1, the theoretical treatment of the cylindrical shell and disk source acquisition sources was recognized by the Los Alamos National Laboratory as suitable for including in the Safeguards Training Program.8 Therefore, we felt it was important to accurately demonstrate the calculus describing the cylindrical shell configuration for the HpGe detector and to theoretically account for the observed bare-detector efficiencies measured in references (3-6). In this paper we demonstrate the applicability of the cylindrical shell derivation to a flexible planar sheet of known Am-241, Eu-152, and Cs-137 activity that we rolled into a symmetrical cylindrical shell of radioactivity. Using the geometry correction equation of reference 1, we calculate geometry correction values using the known detector and source dimensions combined with source to detector distances. We then compare measured detection efficiencies from a cylindrical shell of activity for the 185.7-keV photon (U-235) and for the 414.3-keV photon (Pu-239) with those determined for a 12-inch point source(2,7) to demonstrate agreement between experiment and the theoretically calculated values derived by the Savannah River National Laboratory (SRNL) authors of reference 1. We demonstrate this geometry correction first for the 185.7- and 414.3-keV {gamma}-rays. But because the detector was point source calibrated at 12 inches for the energy range (60 -1700) keV (using two distinct sources) to map its intrinsic efficiency, the geometry correction for any acquisition configuration holds for all photon energies.2 We demonstrate that for ten photon energies in the range 121 keV to 967 keV. The good agreement between experiment and calculation is demonstrated at five source to detector distances using the identical shielded HpGe detector of references 4-7 as well as with a separate HpGe detector. We then extend the measurement to include a single acquisition where the flexible source is wrapped around the bare detector in a symmetrical cylinder tha

  5. Small Scale Assessment of Spatial and Vertical Redistribution of Fukushima Fallouts Radiocaesium in Contaminated Soil Using in-situ HPGe Gamma Ray Spectrometry

    NASA Astrophysics Data System (ADS)

    Patin, J.; Onda, Y.; Yoda, H.; Kato, H.

    2011-12-01

    After Tohoku earthquake on March 11th 2011, the subsequent tsunami and the resulting Fukushima Daiichi Nuclear Power Plant disaster, gamma emitting particles, first release into the atmosphere, were quickly deposited on the soil surface, with potentially harmful level in the surroundings of the nuclear power plant. Thus, the evaluation of soil deposition pattern, depth migration and afterward radionuclides redistribution and export by erosion and hydrological processes is fundamental for contamination assessments and to plan future actions. Our study site is located 37km from Fukushima power plant, inside the evacuated zone. In this study, we used a bounded erosion plot of 22.1m x 5m to assess global export of sediments and 137Cs. This plot, previously cropped with tobacco, is morphologically divided into inter-rill areas separated by rills that formed into former wheel tracks. The bottom of the plot is subject to deposition of sediments. In order to determine and quantify the internal processes responsible of the export of sediment, the depth distribution of 137Cs is estimated using a portable High Purity Germanium (HPGe) detector. Such a portable device, associated to the high radiation levels, allow an acquisition of spatially distributed data within the plot in a reasonable time (1 min/sample). At the same time, depth distribution of 137Cs are measured using the scrapper plate technique, adapted to obtain a fine resolution in the first, highly contaminated, centimeters of soil. Finally, 137Cs depth profiles, associated with in situ and laboratory gamma spectrums acquired with the portable detector, allow for the detector calibration. Although the initial deposit can reasonably be supposed homogeneous at the plot scale, the dataset obtained 3 months later shows high spatial and temporal variability due to erosion processes. Measurements with the portable HPGe detector proved to be useful at this small scale, avoiding the needs of a large number of soil samples, and our results are promising to understand erosion at larger scale where horizontal patterns of deposition and redistribution are usually supposed homogeneous over quite larger areas.

  6. Towards high efficiency solid-state thermal and fast neutron detectors This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-print Network

    Danon, Yaron

    Towards high efficiency solid-state thermal and fast neutron detectors This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2012 JINST 7 C03014 (http://iopscience.iop.org/1748-0221/7/03/C03014) Download details: IP Address: 128.113.44.9 The article was downloaded on 27

  7. High detection efficiency micro-structured solid-state neutron detector with extremely low leakage current fabricated with continuous p-n junction

    E-print Network

    Danon, Yaron

    voltage to be $26%. These results are very encouraging for fabrication of large area solid-state neutron-state neutron detectors possessing high neu- tron detection efficiency, large detection area, and low gamma formation in honeycomb structured Si diode by in situ boron deposition and diffusion process using low

  8. Strategy of HPGe screening measurements in the SuperNEMO experiment

    SciTech Connect

    Perrot, Frédéric [Université de Bordeaux, Centre d'Etudes Nucléaires de Bordeaux Gradignan, UMR 5797, Chemin du Solarium, Le Haut-Vigneau, BP120, F-33175 Gradignan, France and CNRS Collaboration: SuperNEMO Collaboration

    2013-08-08

    SuperNEMO is a double beta decay experiment that will use a tracko-calorimeter technique. The goal is to reach a sensitivity of T{sub 1/2}(0?)>10{sup 26} y corresponding to an effective Majorana neutrino mass of 0.04-0.11 eV with 100 kg of {sup 82}Se. The general strategy of the HPGe screening measurements is described for the materials of the SuperNEMO demonstrator, regarding their radiopurity and their location. The two platforms, PRISNA and LSM, used for this screening are also briefly described.

  9. High Throughput, High Yield Fabrication of High Quantum Efficiency Back-Illuminated Photon Counting, Far UV, UV, and Visible Detector Arrays

    NASA Technical Reports Server (NTRS)

    Nikzad, Shouleh; Hoenk, M. E.; Carver, A. G.; Jones, T. J.; Greer, F.; Hamden, E.; Goodsall, T.

    2013-01-01

    In this paper we discuss the high throughput end-to-end post fabrication processing of high performance delta-doped and superlattice-doped silicon imagers for UV, visible, and NIR applications. As an example, we present our results on far ultraviolet and ultraviolet quantum efficiency (QE) in a photon counting, detector array. We have improved the QE by nearly an order of magnitude over microchannel plates (MCPs) that are the state-of-the-art UV detectors for many NASA space missions as well as defense applications. These achievements are made possible by precision interface band engineering of Molecular Beam Epitaxy (MBE) and Atomic Layer Deposition (ALD).

  10. Operation of a GERDA Phase I prototype detector in liquid argon and nitrogen

    E-print Network

    M. Barnabé Heider; A. Bakalyarov; L. Bezrukov; C. Cattadori; O. Chkvorets; K. Gusev; M. Hult; I. Kirpichnikov; V. Lebedev; G. Marissens; P. Peiffer; S. Schönert; M. Shirchenko; A. Smolnikov; A. Vasenko; S. Vasiliev; S. Zhukov

    2008-12-20

    The GERDA (GERmanium Detector Array) experiment aiming to search for the neutrinoless double beta decay of 76Ge at the Laboratori Nazionali Del Gran Sasso (LNGS), Italy, will operate bare enriched high-purity germanium (HPGe) detectors in liquid argon. GERDA Phase I will use the enriched diodes from the previous Heidelberg-Moscow (HdM) and IGEX experiments. With the HPGe detectors mounted in a low-mass holder, GERDA aims at an excellent energy resolution and extremely low background. The goal is to check the claim for the neutrinoless double beta decay evidence in the HdM 76Ge experiment within one year of data taking. Before dismounting the enriched diodes from their cryostat, the performance parameters of the HdM and the IGEX detectors have been measured. The diodes have been removed from their cryostats, their dimensions measured and they have been put under va-cuum in a transportation container. They are now being refurbished for GERDA Phase I at Canberra Semiconductor NV. Before operating the enriched diodes, a non-enriched HPGe p-type detector mounted in a low-mass holder is operated in the liquid argon test facility of the GERDA Detector Laboratory (GDL) at LNGS. Since January 2006, the testing of the prototype detector is being carried out in the GDL as well as at the site of the detector manufacturer.

  11. High detection efficiency micro-structured solid-state neutron detector with extremely low leakage current fabricated with continuous p-n junction

    SciTech Connect

    Huang, Kuan-Chih; Lu, James J.-Q.; Bhat, Ishwara B.; Dahal, Rajendra; Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180-3522 ; Danon, Yaron

    2013-04-15

    We report the continuous p-n junction formation in honeycomb structured Si diode by in situ boron deposition and diffusion process using low pressure chemical vapor deposition for solid-state thermal neutron detection applications. Optimized diffusion temperature of 800 Degree-Sign C was obtained by current density-voltage characteristics for fabricated p{sup +}-n diodes. A very low leakage current density of {approx}2 Multiplication-Sign 10{sup -8} A/cm{sup 2} at -1 V was measured for enriched boron filled honeycomb structured neutron detector with a continuous p{sup +}-n junction. The neutron detection efficiency for a Maxwellian spectrum incident on the face of the detector was measured under zero bias voltage to be {approx}26%. These results are very encouraging for fabrication of large area solid-state neutron detector that could be a viable alternative to {sup 3}He tube based technology.

  12. Cascaded-systems analyses and the detective quantum efficiency of single-Z x-ray detectors including photoelectric, coherent and incoherent interactions

    SciTech Connect

    Yun, Seungman; Tanguay, Jesse; Cunningham, Ian A.; Kim, Ho Kyung

    2013-04-15

    Purpose: Theoretical models of the detective quantum efficiency (DQE) of x-ray detectors are an important step in new detector development by providing an understanding of performance limitations and benchmarks. Previous cascaded-systems analysis (CSA) models accounted for photoelectric interactions only. This paper describes an extension of the CSA approach to incorporate coherent and incoherent interactions, important for low-Z detectors such as silicon and selenium. Methods: A parallel-cascade approach is used to describe the three types of x-ray interactions. The description of incoherent scatter required developing expressions for signal and noise transfer through an 'energy-labeled reabsorption' process where the parameters describing reabsorption are random functions of the scatter photon energy. The description of coherent scatter requires the use of scatter form factors that may not be accurate for some crystalline detector materials. The model includes the effects of scatter reabsorption and escape, charge collection, secondary quantum sinks, noise aliasing, and additive noise. Model results are validated by Monte Carlo calculations for Si and Se detectors assuming free-atom atomic form factors. Results: The new signal and noise transfer expressions were validated by showing agreement with Monte Carlo results. Coherent and incoherent scatter can degrade the DQE of Si and sometimes Se detectors depending on detector thickness and incident-photon energy. Incoherent scatter can produce a substantial low-frequency drop in the modulation transfer function and DQE. Conclusions: A generally useful CSA model of the DQE is described that is believed valid for any single-Z material up to 10 cycles/mm at both mammographic and radiographic energies within the limitations of Fourier-based linear-systems models and the use of coherent-scatter form factors. The model describes a substantial low-frequency drop in the DQE of Si systems due to incoherent scatter above 20-40 keV.

  13. Neutrino Detectors: Challenges and Opportunities

    SciTech Connect

    Soler, F. J. P.

    2011-10-06

    This paper covers possible detector options suitable at future neutrino facilities, such as Neutrino Factories, Super Beams and Beta Beams. The Magnetised Iron Neutrino Detector (MIND), which is the baseline detector at a Neutrino Factory, will be described and a new analysis which improves the efficiency of this detector at low energies will be shown. Other detectors covered include the Totally Active Scintillating Detectors (TASD), particularly relevant for a low energy Neutrino Factory, emulsion detectors for tau detection, liquid argon detectors and megaton scale water Cherenkov detectors. Finally the requirements of near detectors for long-baseline neutrino experiments will be demonstrated.

  14. Theoretical investigation of very high quantum efficiency, segmented, crystalline detectors for low-contrast visualization in megavoltage cone-beam CT

    NASA Astrophysics Data System (ADS)

    Wang, Yi; Antonuk, Larry E.; El-Mohri, Youcef; Sawant, Amit; Zhao, Qihua; Du, Hong; Li, Yixin

    2006-03-01

    Megavoltage cone-beam computed tomography (CBCT) using active matrix flat-panel imagers (AMFPIs) is a promising candidate for providing image guidance in radiation therapy. Unfortunately, the practical clinical implementation of this technique is limited by the relatively low detective quantum efficiency (DQE) of conventional megavoltage AMFPIs. This limitation is due to the modest thickness of the phosphor screen employed to convert incident x-rays to optical photons and the trade-off that exists between phosphor thickness and spatial resolution. Recently, our group has begun pursuing the development of thick crystalline segmented scintillating detectors as x-ray converters for AMFPIs so as to circumvent this limitation. In order to examine the potential of such detectors for providing soft-tissue visualization by means of CBCT at megavoltage energies, a Monte Carlo-based method was used to simulate the acquisition of projection images of a contrast phantom. These images were used to perform CT reconstructions by means of a Feldkamp-based algorithm. In this study, various detector configurations involving CsI and BGO scintillators at thicknesses of 10 mm and 40 mm were evaluated. In addition, since the simulations only considered energy deposition, and did not include optical phenomena, both segmented and non-segmented (continuous) detector configurations were evaluated. For the segmented CsI detectors, septal wall materials with densities lower, equivalent and higher than that of the scintillator were considered. Performance was quantified in terms of the contrast-to-noise ratio obtained for lowcontrast, soft-tissue-equivalent objects (i.e., liver, brain, and breast) embedded in the phantom. The results obtained from these early studies suggest that such segmented converters can provide visualization of soft-tissue contrast in tomographic images at clinically practical doses. It is anticipated that the realization of optimized segmented detector designs will lead to clinically useful megavoltage AMFPIs exhibiting impressive performance.

  15. Gamma-ray detection efficiency of the microchannel plate installed as an ion detector in the low energy particle instrument onboard the GEOTAIL satellite

    SciTech Connect

    Tanaka, Y. T.; Yoshikawa, I.; Yoshioka, K.; Terasawa, T.; Saito, Y.; Mukai, T.

    2007-03-15

    A microchannel plate (MCP) assembly has been used as an ion detector in the low energy particle (LEP) instrument onboard the magnetospheric satellite GEOTAIL. Recently the MCP assembly has detected gamma rays emitted from an astronomical object and has been shown to provide unique information of gamma rays if they are intense enough. However, the detection efficiency for gamma rays was not measured before launch, and therefore we could not analyze the LEP data quantitatively. In this article, we report the gamma-ray detection efficiency of the MCP assembly. The measured efficiencies are 1.29%{+-}0.71% and 0.21%{+-}0.14% for normal incidence 60 and 662 keV gamma rays, respectively. The incident angle dependence is also presented. Our calibration is crucial to study high energy astrophysical phenomena by using the LEP.

  16. Efficiency of the cross-correlation statistic for gravitational wave stochastic background signals with non-Gaussian noise and heterogeneous detector sensitivities

    NASA Astrophysics Data System (ADS)

    Martellini, Lionel; Regimbau, Tania

    2015-11-01

    Under standard assumptions including stationary and serially uncorrelated Gaussian gravitational wave stochastic background signal and noise distributions, as well as homogenous detector sensitivities, the standard cross-correlation detection statistic is known to be optimal in the sense of minimizing the probability of a false dismissal at a fixed value of the probability of a false alarm. The focus of this paper is to analyze the comparative efficiency of this statistic, vs a simple alternative statistic obtained by cross-correlating the squared measurements, in situations that deviate from such standard assumptions. We find that differences in detector sensitivities have a large impact on the comparative efficiency of the cross-correlation detection statistic, which is dominated by the alternative statistic when these differences reach 1 order of magnitude. This effect holds even when both the signal and noise distributions are Gaussian. While the presence of non-Gaussian signals has no material impact for reasonable parameter values, the relative inefficiency of the cross-correlation statistic is less prominent for fat-tailed noise distributions, but it is magnified in case noise distributions have skewness parameters of opposite signs. Our results suggest that introducing an alternative detection statistic can lead to noticeable sensitivity gains when noise distributions are possibly non-Gaussian and/or when detector sensitivities exhibit substantial differences, a situation that is expected to hold in joint detections from Advanced LIGO and Advanced Virgo, in particular in the early phases of development of the detectors, or in joint detections from Advanced LIGO and the Einstein Telescope.

  17. Enhanced Detection Efficiency of Direct Conversion X-ray Detector Using Polyimide as Hole-Blocking Layer

    NASA Astrophysics Data System (ADS)

    Abbaszadeh, Shiva; Scott, Christopher C.; Bubon, Oleksandr; Reznik, Alla; Karim, Karim S.

    2013-11-01

    In this article we demonstrate the performance of a direct conversion amorphous selenium (a-Se) X-ray detector using biphenyldisnhydride/1,4 phenylenediamine (BPDA/PPD) polyimide (PI) as a hole-blocking layer. The use of a PI layer with a-Se allows detector operation at high electric fields (>=10 V/?m) while maintaining low dark current, without deterioration of transient performance. The hole mobility of the PI/a-Se device is measured by the time-of-flight method at different electric fields to investigate the effect of the PI layer on detector performance. It was found that hole mobility as high as 0.75 cm2/Vs is achievable by increasing the electric field in the PI/a-Se device structure. Avalanche multiplication is also shown to be achievable when using PI as a blocking layer. Increasing the electric field within a-Se reduces the X-ray ionization energy, increases hole mobility, and improves the dynamic range and sensitivity of the detector.

  18. Shaped detector

    SciTech Connect

    Carlson, R.W.

    1981-09-29

    A radiation detector or detector array which has a non-constant spatial response, is disclosed individually and in combination with a tomographic scanner. The detector has a first dimension which is oriented parallel to the plane of the scan circle in the scanner. Along the first dimension, the detector is most responsive to radiation received along a centered segment of the dimension and less responsive to radiation received along edge segments. This non-constant spatial response can be achieved in a detector comprised of a scintillation crystal and a photoelectric transducer. The scintillation crystal in one embodiment is composed of three crystals arranged in layers, with the center crystal having the greatest light conversion efficiency. In another embodiment, the crystal is covered with a reflective substance around the center segment and a less reflective substance around the remainder. In another embodiment, an optical coupling which transmits light from adjacent the center segment with the greatest intensity couples the scintillation crystal and the photoelectric transducer. In yet another embodiment, the photoelectric transducer comprises three photodiodes, one receiving light produced adjacent the central segment and the other two receiving light produced adjacent the edge segments. The outputs of the three photodiodes are combined with a differential amplifier.

  19. Empirical assessment of the detection efficiency of CR-39 at high proton fluence and a compact, proton detector for high-fluence applications

    SciTech Connect

    Rosenberg, M. J.; Séguin, F. H.; Waugh, C. J.; Rinderknecht, H. G.; Orozco, D.; Frenje, J. A.; Johnson, M. Gatu; Sio, H.; Zylstra, A. B.; Sinenian, N.; Li, C. K.; Petrasso, R. D.; Glebov, V. Yu.; Stoeckl, C.; Hohenberger, M.; Sangster, T. C.; LePape, S.; Mackinnon, A. J.; Bionta, R. M.; Landen, O. L.; Zacharias, R. A.; Kim, Y.; Herrmann, H. W.; Kilkenny, J. D.

    2014-04-14

    CR-39 solid-state nuclear track detectors are widely used in physics and in many inertial confinement fusion (ICF) experiments, and under ideal conditions these detectors have 100% detection efficiency for ~0.5–8 MeV protons. When the fluence of incident particles becomes too high, the overlap of particle tracks leads to under-counting at typical processing conditions (5h etch in 6N NaOH at 80°C). Short etch times required to avoid overlap can cause under-counting as well, as tracks are not fully developed. Experiments have determined the minimum etch times for 100% detection of 1.7–4.3-MeV protons and established that for 2.4-MeV protons, relevant for detection of DD protons, the maximum fluence that can be detected using normal processing techniques is ?3 ×106 cm-2. A CR-39-based proton detector has been developed to mitigate issues related to high particle fluences on ICF facilities. Using a pinhole and scattering foil several mm in front of the CR-39, proton fluences at the CR-39 are reduced by more than a factor of ~50, increasing the operating yield upper limit by a comparable amount.

  20. Empirical assessment of the detection efficiency of CR-39 at high proton fluence and a compact, proton detector for high-fluence applications

    DOE PAGESBeta

    Rosenberg, M. J.; Séguin, F. H.; Waugh, C. J.; Rinderknecht, H. G.; Orozco, D.; Frenje, J. A.; Johnson, M. Gatu; Sio, H.; Zylstra, A. B.; Sinenian, N.; et al

    2014-04-14

    CR-39 solid-state nuclear track detectors are widely used in physics and in many inertial confinement fusion (ICF) experiments, and under ideal conditions these detectors have 100% detection efficiency for ~0.5–8 MeV protons. When the fluence of incident particles becomes too high, the overlap of particle tracks leads to under-counting at typical processing conditions (5h etch in 6N NaOH at 80°C). Short etch times required to avoid overlap can cause under-counting as well, as tracks are not fully developed. Experiments have determined the minimum etch times for 100% detection of 1.7–4.3-MeV protons and established that for 2.4-MeV protons, relevant for detectionmore ťof DD protons, the maximum fluence that can be detected using normal processing techniques is ?3 ×106 cm-2. A CR-39-based proton detector has been developed to mitigate issues related to high particle fluences on ICF facilities. Using a pinhole and scattering foil several mm in front of the CR-39, proton fluences at the CR-39 are reduced by more than a factor of ~50, increasing the operating yield upper limit by a comparable amount.Ť less

  1. High-resolution gamma-ray measurement systems using a compact electro- mechanically cooled detector system and intelligent software

    SciTech Connect

    Buckley, W.M.; Carlson, J.B.; Neufeld, K.W.

    1995-09-27

    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{sub 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.

  2. Investigation of quantum efficiency in mid-wave infrared (MWIR) InAs/GaSb type-II strained layer superlattice (T2SL) detectors

    NASA Astrophysics Data System (ADS)

    Acosta, Lilian; Klein, Brianna; Tian, Zhao-Bing; Frantz, Eric; Myers, Stephen; Gautam, Nutan; Schuler-Sandy, Ted; Plis, Elena; Krishna, Sanjay

    2014-02-01

    The objective of this study is to optimize the absorption in the active region of InAs/GaSb T2SL photodetectors for the realization of high-performance MWIR devices. Two sets of MWIR (?100% cut-off ~ 5.5?m at 77K) T2SL detectors were realized; one set with varied detector absorber thickness, the other set with varied T2SL period. The T2SL material quality was evaluated on the basis of room temperature photoluminescence (RTPL) and the high-resolution X-ray diffraction (HRXRD) data. Then the device performance was compared using spectral response, dark current and responsivity measurements. Finally, quantum efficiency was calculated and employed as a metric for the definition of the optimal T2SL period and active region thickness. For the first part of the study, a homojunction pin architecture based on 8 monolayers (MLs) InAs/8MLs GaSb T2SL was used. The thickness of the non-intentionally doped absorber layers were 1.5?m, 2.5?m, and 3.5?m. For the second part of the study, unipolar barrier (pBiBn) devices were grown. The thickness of the absorber region and the T2SL constituent InAs layer thicknesses were kept the same (1.5 ?m and 8 MLs, respectively) whereas the T2SL constituent GaSb thickness was varied as 6 MLs, 8 MLs, and 10 MLs. We have found that the pin detector with 2.5 ?m thick absorber and the pBiBn detector with 8 ML InAs/ 8 ML GaSb T2SL composition are, within the scope of this study, optimal for the realization of MWIR single-element devices and FPAs with corresponding architectures.

  3. 4{\\pi}{\\beta} (LS)-{\\gamma} (HPGe) Digital Coincidence System Based on Synchronous High-Speed Multichannel Data Acquisition

    E-print Network

    Chen, Jifeng; Liang, Juncheng; Liu, Jiacheng

    2015-01-01

    A dedicated 4{\\pi}{\\beta} (LS)-{\\gamma} (HPGe)digital coincidence system has been developed in this work, which includes five acquisition channels. Three analog-to-digital converter (ADC) acquisition channels with an acquisition resolution of 8 bits and acquisition rate of 1GSPS (sample per second) are utilized to collect the signals from three Photo multiplier tubes (PMTs) which are adopted to detect {\\beta} decay, and two acquisition channels with an acquisition resolution of 16 bits and acquisition rate of 50MSPS are utilized to collect the signals from high-purity germanium (HPGe) which are adopted to detect {\\gamma} decay. In order to increase the accuracy of the coincidence system, all the five acquisition channels are synchronous within 500ps. The data collected by the five acquisition channels will be transmitted to the host PC through PCI bus and saved as a file. Off-line software is applied for the 4{\\pi}{\\beta} (LS)-{\\gamma} (HPGe) coincidence and data analysis as needed in practical application. W...

  4. Experimental investigation of gamma-ray attenuation in Jordanian building materials using HPGe-spectrometer.

    PubMed

    Awadallah, Mohammad I; Imran, Mousa M A

    2007-01-01

    The capabilities of some building materials used in Jordan to attenuate gamma radiation were tested. Measurements of the attenuation coefficients of limestone, bricks and concrete have been carried out using a HPGe-spectrometer. Narrow beam technique was used, with a multiple gamma radiation source of different energy lines. Results indicate that variations in the attenuation coefficient for all limestone samples, at the same energy line, are within the experimental uncertainties. On the basis of the results achieved, an empirical formula mu(m)=AE(-0.44) was proposed to calculate attenuation at various incident energies. Limestone of average thickness 7cm was found to stop 75% of a gamma beam of energy 662keV. Meanwhile a brick of effective thickness 7cm was found to stop 60% of the same beam. The total attenuation coefficient of concrete calculated at 1333keV was 11.2m(-1), which is less than that of limestone and bricks. PMID:17368884

  5. The high-efficiency ?-ray spectroscopy setup ?3 at HI?S

    NASA Astrophysics Data System (ADS)

    Löher, B.; Derya, V.; Aumann, T.; Beller, J.; Cooper, N.; Duchęne, M.; Endres, J.; Fiori, E.; Isaak, J.; Kelley, J.; Knörzer, M.; Pietralla, N.; Romig, C.; Savran, D.; Scheck, M.; Scheit, H.; Silva, J.; Tonchev, A.; Tornow, W.; Weller, H.; Werner, V.; Zilges, A.

    2013-09-01

    The existing Nuclear Resonance Fluorescence (NRF) setup at the HI?S facility at the Triangle Universities Nuclear Laboratory at Duke University has been extended in order to perform ?-? coincidence experiments. The new setup combines large volume LaBr3 : Ce detectors and high resolution HPGe detectors in a very close geometry to offer high efficiency, high energy resolution as well as high count rate capabilities at the same time. The combination of a highly efficient ?-ray spectroscopy setup with the mono-energetic high-intensity photon beam of HI?S provides a worldwide unique experimental facility to investigate the ?-decay pattern of dipole excitations in atomic nuclei. The performance of the new setup has been assessed by studying the nucleus 32S at 8.125 MeV beam energy. The relative ?-decay branching ratio from the 1+ level at 8125.4 keV to the first excited 2+ state was determined to 15.7(3)%.

  6. The high-efficiency ?-ray spectroscopy setup ?3 at HI?S

    E-print Network

    Bastian Löher; Vera Derya; Thomas Aumann; Jacob Beller; Nathan Cooper; Marc Duchene; Janis Endres; Enrico Fiori; Johann Isaak; John Kelley; Michael Knörzer; Norbert Pietralla; Christopher Romig; Marcus Scheck; Heiko Scheit; Joel Silva; Anton P. Tonchev; Werner Tornow; Henry Weller; Volker Werner; Andreas Zilges

    2013-04-23

    The existing Nuclear Resonance Fluorescence (NRF) setup at the HI{\\gamma}S facility at the Triangle Universities Nuclear Laboratory at Duke University has been extended in order to perform {\\gamma}-{\\gamma} coincidence experiments. The new setup combines large volume LaBr3:Ce detectors and high resolution HPGe detectors in a very close geometry to offer high efficiency, high energy resolution as well as high count rate capabilities at the same time. The combination of a highly efficient {\\gamma}-ray spectroscopy setup with the mono-energetic high-intensity photon beam of HI{\\gamma}S provides a worldwide unique experimental facility to investigate the {\\gamma}-decay pattern of dipole excitations in atomic nuclei. The performance of the new setup has been assessed by studying the nucleus \\sulfur at 8.125 MeV beam energy. The {\\gamma}-decay branching ratio from the $1^+$ level at 8125.4 keV to the first excited $2^+$ state was determined to 15.7(3)%.

  7. Segmented crystalline scintillators: Empirical and theoretical investigation of a high quantum efficiency EPID based on an initial engineering prototype CsI(Tl) detector

    SciTech Connect

    Sawant, Amit; Antonuk, Larry E.; El-Mohri, Youcef; Zhao Qihua; Wang Yi; Li Yixin; Du Hong; Perna, Louis

    2006-04-15

    Modern-day radiotherapy relies on highly sophisticated forms of image guidance in order to implement increasingly conformal treatment plans and achieve precise dose delivery. One of the most important goals of such image guidance is to delineate the clinical target volume from surrounding normal tissue during patient setup and dose delivery, thereby avoiding dependence on surrogates such as bony landmarks. In order to achieve this goal, it is necessary to integrate highly efficient imaging technology, capable of resolving soft-tissue contrast at very low doses, within the treatment setup. In this paper we report on the development of one such modality, which comprises a nonoptimized, prototype electronic portal imaging device (EPID) based on a 40 mm thick, segmented crystalline CsI(Tl) detector incorporated into an indirect-detection active matrix flat panel imager (AMFPI). The segmented detector consists of a matrix of 160x160 optically isolated, crystalline CsI(Tl) elements spaced at 1016 {mu}m pitch. The detector was coupled to an indirect detection-based active matrix array having a pixel pitch of 508 {mu}m, with each detector element registered to 2x2 array pixels. The performance of the prototype imager was evaluated under very low-dose radiotherapy conditions and compared to that of a conventional megavoltage AMFPI based on a Lanex Fast-B phosphor screen. Detailed quantitative measurements were performed in order to determine the x-ray sensitivity, modulation transfer function, noise power spectrum, and detective quantum efficiency (DQE). In addition, images of a contrast-detail phantom and an anthropomorphic head phantom were also acquired. The prototype imager exhibited approximately 22 times higher zero-frequency DQE ({approx}22%) compared to that of the conventional AMFPI ({approx}1%). The measured zero-frequency DQE was found to be lower than theoretical upper limits ({approx}27%) calculated from Monte Carlo simulations, which were based solely on the x-ray energy absorbed in the detector--indicating the presence of optical Swank noise. Moreover, due to the nonoptimized nature of this prototype, the spatial resolution was observed to be significantly lower than theoretical expectations. Nevertheless, due to its high quantum efficiency ({approx}55%), the prototype imager exhibited significantly higher DQE than that of the conventional AMFPI across all spatial frequencies. In addition, the frequency-dependent DQE was observed to be relatively invariant with respect to the amount of incident radiation, indicating x-ray quantum limited behavior. Images of the contrast-detail phantom and the head phantom obtained using the prototype system exhibit good visualization of relatively large, low-contrast features, and appear significantly less noisy compared to similar images from a conventional AMFPI. Finally, Monte Carlo-based theoretical calculations indicate that, with proper optimization, further, significant improvements in the DQE performance of such imagers could be achieved. It is strongly anticipated that the realization of optimized versions of such very high-DQE EPIDs would enable megavoltage projection imaging at very low doses, and tomographic imaging from a 'beam's eye view' at clinically acceptable doses.

  8. Effect of the wire width on the intrinsic detection efficiency of superconducting-nanowire single-photon detectors

    SciTech Connect

    Lusche, R. Semenov, A.; Ilin, K.; Siegel, M.; Korneeva, Y.; Trifonov, A.; Korneev, A.; Goltsman, G.; Vodolazov, D.; Hübers, H.-W.

    2014-07-28

    A thorough spectral study of the intrinsic single-photon detection efficiency in superconducting TaN and NbN nanowires with different widths has been performed. The experiment shows that the cut-off of the intrinsic detection efficiency at near-infrared wavelengths is most likely controlled by the local suppression of the barrier for vortex nucleation around the absorption site. Beyond the cut-off quasi-particle diffusion in combination with spontaneous, thermally activated vortex crossing explains the detection process. For both materials, the reciprocal cut-off wavelength scales linearly with the wire width where the scaling factor agrees with the hot-spot detection model.

  9. Measurement and calculation of the efficiency of fission detectors designed to monitor the time dependence of the neutron production of JET

    NASA Astrophysics Data System (ADS)

    Swinhoe, M. T.; Jarvis, O. N.

    1985-05-01

    Three pairs of fission counters (each pair one 235U and one 238U) are used at the Joint European Torus to determine the time dependence of the neutron production. In order to determine the absolute value of the neutron flux at the detector location it is necessary to know the neutron detection efficiency of the counter assemblies. This was measured using monoenergetic neutrons (at 2.5 and 14 MeV) and Cf and Am/Be sources. The fraction of fissions detected was determined by extrapolation of the pulse-height spectrum to zero pulse height. The calculation of efficiency was made with the Monte-Carlo neutron transport code MORSE. It was found that the detailed structure of the counter significantly affected the calculated efficiency and that the thermal cross-section values of the DLC37F nuclear data library had to be replaced with room-temperature values. The mean difference between calculation and experiment is (5.5ą6.3)%.

  10. Intelligent Detector Design

    SciTech Connect

    Graf, N.A.; /SLAC

    2012-06-11

    As the complexity and resolution of imaging detectors increases, the need for detailed simulation of the experimental setup also becomes more important. Designing the detectors requires efficient tools to simulate the detector response and reconstruct the events. We have developed efficient and flexible tools for detailed physics and detector response simulation as well as event reconstruction and analysis. The primary goal has been to develop a software toolkit and computing infrastructure to allow physicists from universities and labs to quickly and easily conduct physics analyses and contribute to detector research and development. The application harnesses the full power of the Geant4 toolkit without requiring the end user to have any experience with either Geant4 or C++, thereby allowing the user to concentrate on the physics of the detector system.

  11. Neutron detector

    DOEpatents

    Stephan, Andrew C. (Knoxville, TN); Jardret; Vincent D. (Powell, TN)

    2011-04-05

    A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

  12. Method for manufacturing solid-state thermal neutron detectors with simultaneous high thermal neutron detection efficiency (>50%) and neutron to gamma discrimination (>1.0E4)

    DOEpatents

    Nikolic, Rebecca J.; Conway, Adam M.; Heineck, Daniel; Voss, Lars F.; Wang, Tzu Fang; Shao, Qinghui

    2013-10-15

    Methods for manufacturing solid-state thermal neutron detectors with simultaneous high thermal neutron detection efficiency (>50%) and neutron to gamma discrimination (>10.sup.4) are provided. A structure is provided that includes a p+ region on a first side of an intrinsic region and an n+ region on a second side of the intrinsic region. The thickness of the intrinsic region is minimized to achieve a desired gamma discrimination factor of at least 1.0E+04. Material is removed from one of the p+ region or the n+ region and into the intrinsic layer to produce pillars with open space between each pillar. The open space is filed with a neutron sensitive material. An electrode is placed in contact with the pillars and another electrode is placed in contact with the side that is opposite of the intrinsic layer with respect to the first electrode.

  13. Efficient implementation of multiple scattering Monte Carlo estimates in time-of-flight neutron spectrometry exploiting wide-area detectors

    NASA Astrophysics Data System (ADS)

    De Francesco, Alessio; Bafile, Ubaldo; Formisano, Ferdinando; Guarini, Eleonora

    2012-02-01

    The substantial upgrade in new-generation reactor-based time-of-flight spectrometers lies in their hugely increased detection area ensuring high neutron-collection power and remarkably good count statistics in relatively short times. Dealing with thousands of time channels and several tens of thousands of detection pixels is, however, quite punishing for data handling and correction. Real-geometry multiple scattering evaluation, even in an approximate way, is often the most demanding step in the treatment of inelastic neutron data, and becomes a very hard task in widely-extended detection geometries, as those of spectrometers like BRISP, IN4 or IN5 at the Institut Laue Langevin in Grenoble. We refreshed our approach to multiple scattering calculations, in order to obtain reasonably accurate real-geometry results in nearly real-time conditions. Our new code, originating from a long standing experience in the application of Monte Carlo (MC) integration techniques to multiple scattering calculations, is now made particularly efficient in computing time both by a careful application of the MC importance sampling method, and by the use of programming languages allowing for an efficient use of matrix algebra to avoid the far slower nested-loop logic of more traditional languages. The concepts at the basis of the algorithm and several implementation details are presented, together with the application to a real experimental test case.

  14. Detective quantum efficiency for photon-counting hybrid pixel detectors in the tender X-ray domain: application to Medipix3RX.

    PubMed

    Rinkel, Jean; Magalhăes, Debora; Wagner, Franz; Meneau, Florian; Cesar Vicentin, Flavio

    2016-01-01

    Synchrotron-radiation-based X-ray imaging techniques using tender X-rays are facing a growing demand, in particular to probe the K absorption edges of low-Z elements. Here, a mathematical model has been developed for estimating the detective quantum efficiency (DQE) at zero spatial frequency in the tender X-ray energy range for photon-counting detectors by taking into account the influence of electronic noise. The experiments were carried out with a Medipix3RX ASIC bump-bonded to a 300?ľm silicon sensor at the Soft X-ray Spectroscopy beamline (D04A-SXS) of the Brazilian Synchrotron Light Laboratory (LNLS, Campinas, Brazil). The results show that Medipix3RX can be used to develop new imaging modalities in the tender X-ray range for energies down to 2?keV. The efficiency and optimal DQE depend on the energy and flux of the photons. The optimal DQE values were found in the 7.9-8.6?keV photon energy range. The DQE deterioration for higher energies due to the lower absorption efficiency of the sensor and for lower energies due to the electronic noise has been quantified. The DQE for 3?keV photons and 1 × 10(4)?photons pixel(-1) s(-1) is similar to that obtained with 19?keV photons. Based on our model, the use of Medipix3RX could be extended down to 2?keV which is crucial for coming applications in imaging techniques at modern synchrotron sources. PMID:26698065

  15. New electronically black neutron detectors

    SciTech Connect

    Drake, D.M.; Feldman, W.C.; Hurlbut, C.

    1986-03-01

    Two neutron detectors are described that can function in a continuous radiation background. Both detectors identify neutrons by recording a proton recoil pulse followed by a characteristic capture pulse. This peculiar signature indicates that the neutron has lost all its energy in the scintillator. Resolutions and efficiencies have been measured for both detectors.

  16. GLAS 532nm Optical Detector

    NASA Technical Reports Server (NTRS)

    LaRue, Ross A.

    1997-01-01

    This report documents fabrication and testing of 532nm optical detectors. Testing procedures included 532nm quantum efficiency, detector gain, and photon counting performance, in particular, photon counting efficiency. 532nm quantum efficiency was measured to be 36% to 39% for the detectors fabricated. Detectors with a GaAs APD anode had measured gains of 12,000 to 15,000 maximum. Photon counting efficiency for the detector with an APD anode was measured to be approximately 80% with a detector gain of 11,000. Measurements made on an identical detector, not fabricated under this contract, had a photon counting efficiency exceeding 90% with a gain of 13,000. A formula is derived in which the photon counting efficiency is determined by the system preamp noise and the peak single photon pulse height which is proportional to detector gain. This formula agrees well with the measured results and indicates that a detector gain of 15,000 is sufficient to provide a counting efficiency of 99.6%.

  17. A simultaneous measurement of the $b$-tagging efficiency scale factor and the $t\\bar{t}$ Production Cross Section at the Collider Detector at Fermilab

    SciTech Connect

    Hussain, Nazim; /McGill U.

    2011-07-01

    The ability to compare results between Monte Carlo and data is imperative in modern experimental high-energy physics analyses. The b-tagging efficiency Scale Factor (SF) allows for an accurate comparison of b quark identification in data samples and Monte Carlo. This thesis presents a simultaneous measurement of the SF for the SecVtx algorithm and the t{bar t} production cross section using 5.6 fb{sup -1} of p{bar p} collision data at {radical}s = 1.96 TeV collected by the Collider Detector at Fermilab (CDF) experiment. The t{bar t} cross section was measured to be 7.26 {+-} 0.47 pb, consistent with prior CDF analyses. The tight SF value was measured to be 0.925 {+-} 0.032 and the loose SF value was measured at 0.967 {+-} 0.033. These are the most precise SF SecVtx measurements to be performed at CDF to date.

  18. Capabilities of germanium detectors. [gamma ray spectoscopy

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

    The gamma ray detection efficiency and energy resolution of germanium detectors is reviewed. A general sensitivity equation for gamma-ray detectors is presented and calculated sensitvity curves are shown for a large volume balloon-borne spectrometer using germanium detectors. Improvement anticipated from a planned satellite experiment using germanium detectors is discussed.

  19. LEDs for Efficient Energy

    ERIC Educational Resources Information Center

    Guerin, David A.

    1978-01-01

    Light-emitting diodes (LEDs) are described and three classroom experiments are given, one to prove the, low power requirements and efficiency of LEDs, an LED on-off detector circuit, and the third an LED photoelectric smoke detector. (BB)

  20. Gamma photon techniques for detection of nucleation in superheated emulsion detectors for neutron dosimetry.

    PubMed

    Priyada, P; Ramar, R; Krishnan, H; Viswanathan, S; Shivaramu

    2014-01-01

    Application of transmission and scattering gamma photon techniques for calibration of superheated emulsion detectors used for neutron dosimetry is described. The bubbles nucleated in the detector due to neutron exposure generate detectable changes in both attenuation and scattering properties of the medium, and the magnitude of change in properties depends on population density of bubbles nucleated and in turn is proportional to neutron dose. The experimental set-up consists of (137)Cs and (241)Am sources and an HPGe detector-based gamma-ray spectrometer. An indigenously developed bubble detector and a commercially available one (BTI, Canada) are used in the present study. Theoretical models for the variation in transmitted and scattered intensities through the bubble detector as a function of neutron dose are formulated, and the experimental results obtained are found to be in good agreement with the models. In the neutron dose region studied, the transmission technique shows better sensitivity than scattering technique. PMID:23864644

  1. Layered semiconductor neutron detectors

    DOEpatents

    Mao, Samuel S; Perry, Dale L

    2013-12-10

    Room temperature operating solid state hand held neutron detectors integrate one or more relatively thin layers of a high neutron interaction cross-section element or materials with semiconductor detectors. The high neutron interaction cross-section element (e.g., Gd, B or Li) or materials comprising at least one high neutron interaction cross-section element can be in the form of unstructured layers or micro- or nano-structured arrays. Such architecture provides high efficiency neutron detector devices by capturing substantially more carriers produced from high energy .alpha.-particles or .gamma.-photons generated by neutron interaction.

  2. HIgh Rate X-ray Fluorescence Detector

    SciTech Connect

    Grudberg, Peter Matthew

    2013-04-30

    The purpose of this project was to develop a compact, modular multi-channel x-ray detector with integrated electronics. This detector, based upon emerging silicon drift detector (SDD) technology, will be capable of high data rate operation superior to the current state of the art offered by high purity germanium (HPGe) detectors, without the need for liquid nitrogen. In addition, by integrating the processing electronics inside the detector housing, the detector performance will be much less affected by the typically noisy electrical environment of a synchrotron hutch, and will also be much more compact than current systems, which can include a detector involving a large LN2 dewar and multiple racks of electronics. The combined detector/processor system is designed to match or exceed the performance and features of currently available detector systems, at a lower cost and with more ease of use due to the small size of the detector. In addition, the detector system is designed to be modular, so a small system might just have one detector module, while a larger system can have many â?? you can start with one detector module, and add more as needs grow and budget allows. The modular nature also serves to simplify repair. In large part, we were successful in achieving our goals. We did develop a very high performance, large area multi-channel SDD detector, packaged with all associated electronics, which is easy to use and requires minimal external support (a simple power supply module and a closed-loop water cooling system). However, we did fall short of some of our stated goals. We had intended to base the detector on modular, large-area detectors from Ketek GmbH in Munich, Germany; however, these were not available in a suitable time frame for this project, so we worked instead with pnDetector GmbH (also located in Munich). They were able to provide a front-end detector module with six 100 m^2 SDD detectors (two monolithic arrays of three elements each) along with associated preamplifiers; these detectors surpassed the performance we expected to get from the Ketek detectors, however they are housed in a sealed module, which does not offer the ease of repair and expandability weâ??d hoped to achieve with the Ketek SDDâ??s. Our packaging efforts were quite successful, as we came up with a very compact way to mount the detector and to house the associated electronics, as well as a very effective way to reliably take out the heat (from the electronics as well as the detectorâ??s Peltier coolers) without risk of condensation and without external airflow or vibration, which could create problems for the target applications. While we were able to design compact processing electronics that fit into the detector assembly, they are still at the prototype stage, and would require a significant redesign to achieve product status. We have not yet tested this detector at a synchrotron facility; we do still plan on working with some close contacts at the nearby Stanford Synchrotron Radiation Laboratory (SSRL) to get some testing with the beam (using existing commercial electronics for readout, as the integrated processor is not ready for use).

  3. Particle Detectors

    NASA Astrophysics Data System (ADS)

    Grupen, Claus; Shwartz, Boris

    2008-03-01

    Preface to the first edition; Preface to the second edition; Introduction; 1. Interactions of particles and radiation with matter; 2. Characteristic properties of detectors; 3. Units of radiation measurements and radiation sources; 4. Accelerators; 5. Main physical phenomena used for particle detection and basic counter types; 6. Historical track detectors; 7. Track detectors; 8. Calorimetry; 9. Particle identification; 10. Neutrino detectors; 11. Momentum measurement and muon detection; 12. Ageing and radiation effects; 13. Example of a general-purpose detector: Belle; 14. Electronics; 15. Data analysis; 16. Applications of particle detectors outside particle physics; 17. Glossary; 18. Solutions; 19. Resumé; Appendixes; Index.

  4. Particle Detectors

    NASA Astrophysics Data System (ADS)

    Grupen, Claus; Shwartz, Boris

    2011-09-01

    Preface to the first edition; Preface to the second edition; Introduction; 1. Interactions of particles and radiation with matter; 2. Characteristic properties of detectors; 3. Units of radiation measurements and radiation sources; 4. Accelerators; 5. Main physical phenomena used for particle detection and basic counter types; 6. Historical track detectors; 7. Track detectors; 8. Calorimetry; 9. Particle identification; 10. Neutrino detectors; 11. Momentum measurement and muon detection; 12. Ageing and radiation effects; 13. Example of a general-purpose detector: Belle; 14. Electronics; 15. Data analysis; 16. Applications of particle detectors outside particle physics; 17. Glossary; 18. Solutions; 19. Resumé; Appendixes; Index.

  5. Photon detectors with gaseous amplification

    SciTech Connect

    Va`vra, J.

    1996-08-01

    Gaseous photon detectors, including very large 4{pi}-devices such as those incorporated in SLD and DELPHI, are finally delivering physics after many years of hard work. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photoelectrons. Among detector builders, there is hardly anybody who did not make mistakes in this area, and who does not have a healthy respect for the problems involved. This point is stressed in this paper, and it is suggested that only a very small operating phase space is available for running gaseous photon detectors in a very large system with good efficiency and few problems. In this paper the authors discuss what was done correctly or incorrectly in first generation photon detectors, and what would be their recommendations for second generation detectors. 56 refs., 11 figs.

  6. Performance of bare high-purity germanium detectors in liquid argon for the GERDA experiment

    E-print Network

    Marik Barnabé Heider; Carla Cattadori; Oleg Chkvorets; Assunta Di Vacri; Konstantin Gusev; Stefan Schönert; Mark Shirchenko

    2008-12-10

    The GERmanium Detector Array, GERDA, will search for neutrinoless double beta decay in 76Ge at the National Gran Sasso Laboratory of the INFN. Bare high-purity germanium detectors enriched in 76Ge will be submerged in liquid argon serving simultaneously as a shield against external radioactivity and as a cooling medium. In GERDA Phase-I, reprocessed enriched-Ge detectors, which were previously operated by the Heidelberg-Moscow and IGEX collaborations, will be redeployed. Before operating the enriched detectors, tests are performed with non-enriched bare HPGe detectors in the GERDA underground Detector Laboratory to test the Phase-I detector assembly, the detector handling protocols, the refurbishment technology and to study the long-term stability in liquid argon. The leakage currents in liquid argon and liquid nitrogen have been extensively studied under varying gamma irradiation conditions. In total three non-enriched high-purity p-type prototype germanium detectors have been operated successfully. The detector performance is stable over the long-term measurements. For the first time, performance of bare high-purity germanium detectors in liquid argon is reported.

  7. Pocked surface neutron detector

    DOEpatents

    McGregor, Douglas (Whitmore Lake, MI); Klann, Raymond (Bolingbrook, IL)

    2003-04-08

    The detection efficiency, or sensitivity, of a neutron detector material such as of Si, SiC, amorphous Si, GaAs, or diamond is substantially increased by forming one or more cavities, or holes, in its surface. A neutron reactive material such as of elemental, or any compound of, .sup.10 B, .sup.6 Li, .sup.6 LiF, U, or Gd is deposited on the surface of the detector material so as to be disposed within the cavities therein. The portions of the neutron reactive material extending into the detector material substantially increase the probability of an energetic neutron reaction product in the form of a charged particle being directed into and detected by the neutron detector material.

  8. A Feasibility Study to Determine Cooling Time and Burnup of ATR Fuel Using a Nondestructive Technique and Three Types of Gamma-ray Detectors

    SciTech Connect

    Jorge Navarro; Rahmat Aryaeinejad,; David W. Nigg

    2011-05-01

    A Feasibility Study to Determine Cooling Time and Burnup of ATR Fuel Using a Nondestructive Technique1 Rahmat Aryaeinejad, Jorge Navarro, and David W Nigg Idaho National Laboratory Abstract Effective and efficient Advanced Test Reactor (ATR) fuel management require state of the art core modeling tools. These new tools will need isotopic and burnup validation data before they are put into production. To create isotopic, burn up validation libraries and to determine the setup for permanent fuel scanner system a feasibility study was perform. The study consisted in measuring short and long cooling time fuel elements at the ATR canal. Three gamma spectroscopy detectors (HPGe, LaBr3, and HPXe) and two system configurations (above and under water) were used in the feasibility study. The first stage of the study was to investigate which detector and system configuration would be better suited for different scenarios. The second stage of the feasibility study was to create burnup and cooling time calibrations using experimental isotopic data collected and ORIGEN 2.2 burnup data. The results of the study establish that a better spectra resolution is achieve with an above the water configuration and that three detectors can be used in the permanent fuel scanner system for different situations. In addition it was conclude that a number of isotopic ratios and absolute measurements could be used to predict ATR fuel burnup and cooling times. 1This work was supported by the U.S. DepartŹment of Energy (DOE) under Battelle Energy Alliance, LLC Contract No. DE-AC07-05ID14517.

  9. Characterization of naturally occurring radioactive materials in Libyan oil pipe scale using a germanium detector and Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Habib, A. S.; Shutt, A. L.; Regan, P. H.; Matthews, M. C.; Alsulaiti, H.; Bradley, D. A.

    2014-02-01

    Radioactive scale formation in various oil production facilities is acknowledged to pose a potential significant health and environmental issue. The presence of such an issue in Libyan oil fields was recognized as early as 1998. The naturally occurring radioactive materials (NORM) involved in this matter are radium isotopes (226Ra and 228Ra) and their decay products, precipitating into scales formed on the surfaces of production equipment. A field trip to a number of onshore Libyan oil fields has indicated the existence of elevated levels of specific activity in a number of locations in some of the more mature oil fields. In this study, oil scale samples collected from different parts of Libya have been characterized using gamma spectroscopy through use of a well shielded HPGe spectrometer. To avoid potential alpha-bearing dust inhalation and in accord with safe working practices at this University, the samples, contained in plastic bags and existing in different geometries, are not permitted to be opened. MCNP, a Monte Carlo simulation code, is being used to simulate the spectrometer and the scale samples in order to obtain the system absolute efficiency and then to calculate sample specific activities. The samples are assumed to have uniform densities and homogeneously distributed activity. Present results are compared to two extreme situations that were assumed in a previous study: (i) with the entire activity concentrated at a point on the sample surface proximal to the detector, simulating the sample lowest activity, and; (ii) with the entire activity concentrated at a point on the sample surface distal to the detector, simulating the sample highest activity.

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

    SciTech Connect

    Howard, Chris; Daigle, Stephen; Buckner, Matt; Erikson, Luke E.; Runkle, Robert C.; Stave, Sean C.; Champagne, Art; Cooper, Andrew; Downen, Lori; Glasgow, Brian D.; Kelly, Keegan; Sallaska, Anne

    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 14N(p,?)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.

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

    NASA Astrophysics Data System (ADS)

    Howard, Chris; Daigle, Stephen; Buckner, Matt; Erikson, Luke E.; Runkle, Robert C.; Stave, Sean C.; Champagne, Arthur E.; Cooper, Andrew; Downen, Lori; Glasgow, Brian D.; Kelly, Keegan; Sallaska, Anne

    2015-05-01

    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,?)15O* 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.

  12. Smoke Detector

    NASA Technical Reports Server (NTRS)

    1979-01-01

    In the photo, Fire Chief Jay Stout of Safety Harbor, Florida, is explaining to young Richard Davis the workings of the Honeywell smoke and fire detector which probably saved Richard's life and that of his teen-age brother. Alerted by the detector's warning, the pair were able to escape their burning home. The detector in the Davis home was one of 1,500 installed in Safety Harbor residences in a cooperative program conducted by the city and Honeywell Inc.

  13. PET detector modules based on novel detector technologies

    SciTech Connect

    Moses, W.W.; Derenzo, S.E.; Budinger, T.F.

    1994-05-01

    A successful PET detector module must identify 511 keV photons with: high efficiency (>85%), high spatial resolution (<5 mm fwhm), low cost (<$600 / in{sup 2}), low dead time (<4 {mu}s in{sup 2}), good timing resolution (<5 ns fwhm for conventional PET, <200 ps fwhm for time of flight), and good energy resolution (<100 keV fwhm), where these requirements are listed in decreasing order of importance. The ``high efficiency`` requirement also implies that the detector modules must pack together without inactive gaps. Several novel and emerging radiation detector technologies could improve the performance of PET detectors. Avalanche photodiodes, PIN photodiodes, metal channel dynode photomultiplier tubes, and new scintillators all have the potential to improve PET detectors significantly.

  14. Spectrum correction algorithm for detectors in airborne radioactivity monitoring equipment NH-UAV based on a ratio processing method

    NASA Astrophysics Data System (ADS)

    Cao, Ye; Tang, Xiao-Bin; Wang, Peng; Meng, Jia; Huang, Xi; Wen, Liang-Sheng; Chen, Da

    2015-10-01

    The unmanned aerial vehicle (UAV) radiation monitoring method plays an important role in nuclear accidents emergency. In this research, a spectrum correction algorithm about the UAV airborne radioactivity monitoring equipment NH-UAV was studied to measure the radioactive nuclides within a small area in real time and in a fixed place. The simulation spectra of the high-purity germanium (HPGe) detector and the lanthanum bromide (LaBr3) detector in the equipment were obtained using the Monte Carlo technique. Spectrum correction coefficients were calculated after performing ratio processing techniques about the net peak areas between the double detectors on the detection spectrum of the LaBr3 detector according to the accuracy of the detection spectrum of the HPGe detector. The relationship between the spectrum correction coefficient and the size of the source term was also investigated. A good linear relation exists between the spectrum correction coefficient and the corresponding energy (R2=0.9765). The maximum relative deviation from the real condition reduced from 1.65 to 0.035. The spectrum correction method was verified as feasible.

  15. A mobile antineutrino detector with plastic scintillators

    E-print Network

    Yasuhiro Kuroda; Shugo Oguri; Yo Kato; Ryoko Nakata; Yoshizumi Inoue; Chikara Ito; Makoto Minowa

    2012-06-28

    We propose a new type segmented antineutrino detector made of plastic scintillators for the nuclear safeguard application. A small prototype was built and tested to measure background events. A satisfactory unmanned field operation of the detector system was demonstrated. Besides, a detailed Monte Carlo simulation code was developed to estimate the antineutrino detection efficiency of the detector.

  16. Lanthanum Bromide Detectors for Safeguards Measurements

    SciTech Connect

    Wright, J.

    2011-05-25

    Lanthanum bromide has advantages over other popular inorganic scintillator detectors. Lanthanum bromide offers superior resolution, and good efficiency when compared to sodium iodide and lanthanum chloride. It is a good alternative to high purity germanium detectors for some safeguards applications. This paper offers an initial look at lanthanum bromide detectors. Resolution of lanthanum bromide will be compared lanthanum chloride and sodium-iodide detectors through check source measurements. Relative efficiency and angular dependence will be looked at. Nuclear material spectra, to include plutonium and highly enriched uranium, will be compared between detector types.

  17. Characterization of prototype perforated semiconductor neutron detectors

    NASA Astrophysics Data System (ADS)

    Henderson, C. M.; Jahan, Q. M.; Dunn, W. L.; Shultis, J. K.; McGregor, D. S.

    2010-02-01

    Semiconductor detectors whose surfaces are coated with neutron-reactive material can be made to detect thermal neutrons, but with efficiencies only of a few percent. However, perforating the semiconductor material, filling the perforations with neutron-reactive material, and then coating the detector surface can lead to neutron detectors of much higher thermal neutron detection efficiencies, perhaps approaching or exceeding 50%. Several perforated semiconductor neutron detectors have been constructed, both for dosimetry and for position-sensitive neutron detection. The characterization of prototype devices based on these detectors is described.

  18. Fire Detector

    NASA Technical Reports Server (NTRS)

    1978-01-01

    An early warning fire detection sensor developed for NASA's Space Shuttle Orbiter is being evaluated as a possible hazard prevention system for mining operations. The incipient Fire Detector represents an advancement over commercially available smoke detectors in that it senses and signals the presence of a fire condition before the appearance of flame and smoke, offering an extra margin of safety.

  19. Vapor Detector

    NASA Technical Reports Server (NTRS)

    Waddell, H. M.; Garrard, G. C.; Houston, D. W.

    1982-01-01

    Detector eliminates need for removing covers to take samples. Detector is canister consisting of screw-in base and clear plastic tube that contains two colors of silica gel. Monoethylhydrazine and nitrogen tetroxide vapors are visually monitored with canister containing color-changing gels.

  20. Analysis of Cadmium Based Neutron Detector Configurations

    NASA Astrophysics Data System (ADS)

    James, Brian; Rees, Lawrence; Czirr, J. Bart

    2012-10-01

    Due to national security concerns pertaining to the smuggling of special nuclear materials and a small supply of He-3 for use in neutron detectors, there is currently a need for a new kind of neutron detector. Using Monte Carlo techniques I have studied the neutron capture efficiency of an array of cadmium wedge detectors in the presence of a californium source. By using varying numbers of wedges and comparing their capture ratios we will be better able to design future detectors.

  1. Pulse shape analysis of a two fold clover detector with empirical mode decomposition based algorithm

    NASA Astrophysics Data System (ADS)

    Siwal, Davinder; Mandal, S.; Palit, R.; Schaffner, H.; Adamczewski, J.; Kurz, N.; Naidu, B. S.; Wollersheim, H. J.; Singh, R.

    2014-08-01

    A study of Second-Generation HPGe detectors, which aim at high resolution gamma spectroscopy are underway. The study will utilize the concept of Compton imaging in semiconductors, which will be probed by the Pulse Shape Analysis (PSA) and Gamma-Ray Tracking (GRT) algorithms. The ?-ray track vertices inside the detector volume can be found by analyzing the core and mirror signals which result from different kinds of couplings among the electrodes. The energy accuracy of the reconstructed tracks will depend on the accuracy of the co-ordinate reconstruction. In the present investigation such co-ordinate reconstruction has been done under Empirical Mode Decomposition (EMD) based algorithm. The implications of EMD on pulse shapes of signals from a two fold clover detector has been studied.

  2. Ionization-based detectors for gas chromatography.

    PubMed

    Poole, Colin F

    2015-11-20

    The gas phase ionization detectors are the most widely used detectors for gas chromatography. The column and makeup gases commonly used in gas chromatography are near perfect insulators. This facilitates the detection of a minute number of charge carriers facilitating the use of ionization mechanisms of low efficiency while providing high sensitivity. The main ionization mechanism discussed in this report are combustion in a hydrogen diffusion flame (flame ionization detector), surface ionization in a plasma (thermionic ionization detector), photon ionization (photoionization detector and pulsed discharge helium ionization detector), attachment of thermal electrons (electron-capture detector), and ionization by collision with metastable helium species (helium ionization detector). The design, response characteristics, response mechanism, and suitability for fast gas chromatography are the main features summarized in this report. Mass spectrometric detection and atomic emission detection, which could be considered as ionization detectors of a more sophisticated and complex design, are not discussed in this report. PMID:25757823

  3. Characteristics of signals originating near the lithium-diffused N+ contact of high purity germanium p-type point contact detectors

    NASA Astrophysics Data System (ADS)

    Aguayo, E.; Amman, M.; Avignone, F. T.; Barabash, A. S.; Barton, P. J.; Beene, J. R.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Chan, Y.-D.; Christofferson, C. D.; Collar, J. I.; Combs, D. C.; Cooper, R. J.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J. E.; Fields, N.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Gehman, V. M.; Giovanetti, G. K.; Green, M. P.; Guiseppe, V. E.; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hoppe, E. W.; Horton, M.; Howard, S.; Howe, M. A.; Johnson, R. A.; Keeter, K. J.; Kidd, M. F.; Knecht, A.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; Laferriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; Looker, Q.; Luke, P. N.; Macmullin, S.; Marino, M. G.; Martin, R. D.; Merriman, J. H.; Miller, M. L.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; Overman, N. R.; Perumpilly, G.; Phillips, D. G.; Poon, A. W. P.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Ronquest, M. C.; Schubert, A. G.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Steele, D.; Strain, J.; Timkin, V.; Tornow, W.; Varner, R. L.; Vetter, K.; Vorren, K.; Wilkerson, J. F.; Yakushev, E.; Yaver, H.; Young, A. R.; Yu, C.-H.; Yumatov, V.; Majorana Collaboration

    2013-02-01

    A study of signals originating near the lithium-diffused n+ contact of p-type point contact (PPC) high purity germanium detectors (HPGe) is presented. The transition region between the active germanium and the fully dead layer of the n+ contact is examined. Energy depositions in this transition region are shown to result in partial charge collection. This provides a mechanism for events with a well defined energy to contribute to the continuum of the energy spectrum at lower energies. A novel technique to quantify the contribution from this source of background is introduced. Experiments that operate germanium detectors with a very low energy threshold may benefit from the methods presented herein.

  4. Characteristics of Signals Originating Near the Lithium-Diffused N+ Contact of High Purity Germanium P-Type Point Contact Detectors

    E-print Network

    The MAJORANA Collaboration; E. Aguayo; M. Amman; F. T. Avignone III; A. S. Barabash; P. J. Barton; J. R. Beene; F. E. Bertrand; M. Boswell; V. Brudanin; M. Busch; Y-D. Chan; C. D. Christofferson; J. I. Collar; D. C. Combs; R. J. Cooper; J. A. Detwiler; P. J. Doe; Yu. Efremenko; V. Egorov; H. Ejiri; S. R. Elliott; J. Esterline; J. E. Fast; N. Fields; P. Finnerty; F. M. Fraenkle; A. Galindo-Uribarri; V. M. Gehman; G. K. Giovanetti; M. P. Green; V. E. Guiseppe; K. Gusey; A. L. Hallin; R. Hazama; R. Henning; E. W. Hoppe; M. Horton; S. Howard; M. A. Howe; R. A. Johnson; K. J. Keeter; M. F. Kidd; A. Knecht; O. Kochetov; S. I. Konovalov; R. T. Kouzes; B. D. LaFerriere; J. Leon; L. E. Leviner; J. C. Loach; Q. Looker; P. N. Luke; S. MacMullin; M. G. Marino; R. D. Martin; J. H. Merriman; M. L. Miller; L. Mizouni; M. Nomachi; J. L. Orrell; N. R. Overman; G. Perumpilly; D. G. Phillips II; A. W. P. Poon; D. C. Radford; K. Rielage; R. G. H. Robertson; M. C. Ronquest; A. G. Schubert; T. Shima; M. Shirchenko; K. J. Snavely; D. Steele; J. Strain; V. Timkin; W. Tornow; R. L. Varner; K. Vetter; K. Vorren; J. F. Wilkerson; E. Yakushev; H. Yaver; A. R. Young; C. -H. Yu; V. Yumatov

    2012-07-28

    A study of signals originating near the lithium-diffused n+ contact of p-type point contact (PPC) high purity germanium detectors (HPGe) is presented. The transition region between the active germanium and the fully dead layer of the n+ contact is examined. Energy depositions in this transition region are shown to result in partial charge collection. This provides a mechanism for events with a well defined energy to contribute to the continuum of the energy spectrum at lower energies. A novel technique to quantify the contribution from this source of background is introduced. Experiments that operate germanium detectors with a very low energy threshold may benefit from the methods presented herein.

  5. Characteristics of Signals Originating Near the Lithium-Diffused N+ Contact of High Purity Germanium P-Type Point Contact Detectors

    SciTech Connect

    Aguayo Navarrete, Estanislao; Amman, M.; Avignone, F. T.; Barabash, A.; Barton, P. J.; Beene, Jim; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Collar, Juan; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Galindo-Uribarri, A.; Gehman, Victor M.; Giovanetti, G. K.; Green, Matthew P.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, Reyco; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, Mark; Johnson, R. A.; Keeter, K.; Kidd, Mary; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; Looker, Ron L.; Luke, P.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila K.; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Perumpilly, Gopakumar; Phillips, D.; Poon, Alan; Radford, Davis; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Steele, David; Strain, J.; Timkin, V.; Tornow, W.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Yakushev, E.; Yaver, Harold; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2013-02-11

    A study of signals originating near the lithium-diffused n+ contact of p-type point contact (PPC) high purity germanium detectors (HPGe) is presented. The transition region between the active germanium and the fully dead layer of the n+ contact is examined. Energy depositions in this transition region are shown to result in partial charge collection. This provides a mechanism for events with a well defined energy to contribute to the continuum of the energy spectrum at lower energies. A novel technique to quantify the contribution from this source of background is introduced. Experiments that operate germanium detectors with a very low energy threshold may benefit from the methods presented herein.

  6. Characteristics of Signals Originating near the Lithium-Diffused N+ Contact of High Purity Germanium P-Type Point Contact Detectors

    SciTech Connect

    Aguayo, E.; Amman, M.; Avignone, F. T.; Barton, P. J.; Beene, James R; Bertrand Jr, Fred E; Boswell, M.; Brudanin, V.; Busch, M.; Chan, Y-D; Christofferson, C. D.; Collar, Juan I.; Combs, D. C.; Detwiler, J.A.; Doe, P. J.; Efremenko, Yuri; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J.E.; Fields, N.; Finnerty, P.; Gehman, V. M.; Giovanetti, G. K.; Green, M. P.; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hoppe, E.W.; Horton, M.; Howard, S.; Howe, M. A.; Keeter, K.J.; Kidd, M. F.; Knecht, A.; Kochetov, O.; Konovalov, S.I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Looker, Q.; Luke, P.N.; MacMullin, S.; Martin, R.D.; Merriman, J. H.; Miller, M. L.; Mizouni, L.; Orrell, John L.; Overman, N. R.; Perumpilly, G.; Phillips II, D. G.; et al.

    2013-01-01

    A study of signals originating near the lithium-diffused n+ contact of p-type point contact (PPC) high purity germanium detectors (HPGe) is presented. The transition region between the active germanium and the fully dead layer of the n+ contact is examined. Energy depositions in this transition region are shown to result in partial charge collection. This provides a mechanism for events with a well defined energy to contribute to the continuum of the energy spectrum at lower energies. A novel technique to quantify the contribution from this source of background is introduced. Experiments that operate germanium detectors with a very low energy threshold may benefit from the methods presented herein.

  7. New detectors for the kaon and hypernuclear experiments with KaoS at MAMI and with PANDA at GSI

    E-print Network

    P. Achenbach; C. Ayerbe Gayoso; R. Böhm; M. O. Distler; J. Friedrich; K. W. Krygier; H. Merkel; U. Müller; R. Neuhausen; L. Nungesser; J. Pochodzalla; A. Sanchez Lorente; S. Sánchez Majos; Th. Walcher; J. Gerl; M. Kavatsyuk; I. Kojouhavorv; N. Saito; T. R. Saito; H. Schaffner; T. Bressani; S. Bufalino; A. Feliciello; A. Pantaleo; M. Palomba; G. Raciti; C. Sfienti; M. Agnello; F. Ferro; F. Iazzi; K. Szymanska; P. -E. Tegnér; B. Cederwall; L. Majling

    2006-05-31

    The KaoS spectrometer at the Mainz Microtron MAMI, Germany, is perceived as the ideal candidate for a dedicated spectrometer in kaon and hypernuclei electroproduction. KaoS will be equipped with new read-out electronics, a completely new focal plane detector package consisting of scintillating fibres, and a new trigger system. First prototypes of the fibre detectors and the associated new front-end electronics are shown in this contribution. The Mainz hypernuclei research program will complement the hypernuclear experiments at the planned FAIR facility at GSI, Germany. At the proposed antiproton storage ring the spectroscopy of double Lambda hypernuclei is one of the four main topics which will be addressed by the PANDA Collaboration. The experiments require the operation of high purity germanium (HPGe) detectors in high magnetic fields (B= 1T) in the presence of a large hadronic background. The performance of high resolution Ge detectors in such an environment has been investigated.

  8. Laue Diffraction Using Scintillator Detectors

    NASA Astrophysics Data System (ADS)

    Iles, Gail N.; Peetermans, Steven; Schorr, Susan; Lehmann, Eberhard

    The Fast Acquisition Laue Camera for Neutrons (FALCON) is a thermal neutron Laue diffractometer at HZB in Berlin. The instrument comprises two scintillator plate detectors coupled to four iCCD cameras each. One detector is placed in the backscattering position, enabling neutrons to pass through the centre of the detector box. The second detector is free to be placed either in the direct transmission position, or rotated to positions around the sample. The image-intensified CCDs, supplied by Photonic Science Ltd as components of the detector units, are capable of obtaining 20-bit digitization Laue images in under ten seconds. Whilst our instrument will be used as a diffractometer primarily for crystal structure determination, the configuration of the detectors is similar to ICON at PSI in Switzerland, especially in their 'double detector set-up'. In 2015 FALCON enters the commissioning phase whereby one of our activities will be to calibrate the detector units using CONRAD, the cold neutron imaging instrument of HZB. CONRAD will be used to characterise those factors which affect the total efficiency of the detectors i.e. cameras, lenses, CCD chips and the scintillators themselves e.g. homogeneity of the scintillator plate thickness.

  9. Spatial resolution attainable in germanium detectors by pulse shape analysis

    SciTech Connect

    Blair, J., Bechtel, NV; Beckedahl, D.; Kammeraad, J.; Schmid, G., LLNL

    1998-05-01

    There are several applications for which it is desirable to calculate the locations and energies of individual gamma-ray interactions within a high purity germanium (HPGe) detector. These include gamma-ray imaging and Compton suppression. With a segmented detector this can be accomplished by analyzing the pulse shapes of the signals from the various segments. We examine the fundamental limits to the spatial resolution attainable with this approach. The primary source of error is the series noise of the field effect transistors (FETs) at the inputs of the charge amplifiers. We show how to calculate the noise spectral density at the output of the charge amplifiers due to an optimally selected FET. This calculation is based only on the detector capacitance and a noise constant for the FET technology. We show how to use this spectral density to calculate the uncertainties in parameters, such as interaction locations and energies, that are derived from pulse shape analysis using maximum likelihood estimation (MLE) applied to filtered and digitized recordings of the charge signals. Example calculations are given to illustrate our approach. Experimental results are given that demonstrate that one can construct complete systems, from detector through data analysis, that come near the theoretical limits.

  10. Neutron detectors comprising boron powder

    DOEpatents

    Wang, Zhehui; Morris, Christopher; Bacon, Jeffrey Darnell; Makela, Mark F; Spaulding, Randy Jay

    2013-05-21

    High-efficiency neutron detector substrate assemblies comprising a first conductive substrate, wherein a first side of the substrate is in direct contact with a first layer of a powder material comprising .sup.10boron, .sup.10boron carbide or combinations thereof, and wherein a conductive material is in proximity to the first layer of powder material; and processes of making said neutron detector substrate assemblies.

  11. Microwave detector

    DOEpatents

    Meldner, Heiner W. (Moss Beach, CA); Cusson, Ronald Y. (Chapel Hill, NC); Johnson, Ray M. (San Ramon, CA)

    1986-01-01

    A microwave detector (10) is provided for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations. A biased ferrite (26, 28) produces a magnetization field flux that links a B-dot loop (16, 20). The magnetic field of the microwave pulse participates in the formation of the magnetization field flux. High-frequency insensitive means (18, 22) are provided for measuring electric voltage or current induced in the B-dot loop. The recorded output of the detector is proportional to the time derivative of the square of the envelope shape of the microwave pulse.

  12. Hydrogen detector

    DOEpatents

    Kanegae, Naomichi (Mito, JP); Ikemoto, Ichiro (Mito, JP)

    1980-01-01

    A hydrogen detector of the type in which the interior of the detector is partitioned by a metal membrane into a fluid section and a vacuum section. Two units of the metal membrane are provided and vacuum pipes are provided independently in connection to the respective units of the metal membrane. One of the vacuum pipes is connected to a vacuum gauge for static equilibrium operation while the other vacuum pipe is connected to an ion pump or a set of an ion pump and a vacuum gauge both designed for dynamic equilibrium operation.

  13. Microwave detector

    DOEpatents

    Meldner, H.W.; Cusson, R.Y.; Johnson, R.M.

    1985-02-08

    A microwave detector is provided for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations. A biased ferrite produces a magnetization field flux that links a B-dot loop. The magnetic field of the microwave pulse participates in the formation of the magnetization field flux. High-frequency insensitive means are provided for measuring electric voltage or current induced in the B-dot loop. The recorded output of the detector is proportional to the time derivative of the square of the envelope shape of the microwave pulse.

  14. Silicon Detectors

    NASA Astrophysics Data System (ADS)

    Sadrozinski, Hartmut

    2014-03-01

    The use of silicon detectors has experienced an exponential growth in accelerator and space based experiments, similar to trends in the semiconductor industry as a whole, usually paraphrased as ``Moore's Law.'' Some of the essentials for this phenomenon will be presented, together with examples of the exciting science results which it enabled. With the establishment of a ``semiconductor culture'' in universities and laboratories around the world, an increased understanding of the sensors results in thinner, faster, more radiation-resistant detectors, spawning an amazing wealth of new technologies and applications, which will be the main subject of the presentation.

  15. Efficiency corrections in determining the (137)Cs inventory of environmental soil samples by using relative measurement method and GEANT4 simulations.

    PubMed

    Li, Gang; Liang, Yongfei; Xu, Jiayun; Bai, Lixin

    2015-08-01

    The determination of (137)Cs inventory is widely used to estimate the soil erosion or deposition rate. The generally used method to determine the activity of volumetric samples is the relative measurement method, which employs a calibration standard sample with accurately known activity. This method has great advantages in accuracy and operation only when there is a small difference in elemental composition, sample density and geometry between measuring samples and the calibration standard. Otherwise it needs additional efficiency corrections in the calculating process. The Monte Carlo simulations can handle these correction problems easily with lower financial cost and higher accuracy. This work presents a detailed description to the simulation and calibration procedure for a conventionally used commercial P-type coaxial HPGe detector with cylindrical sample geometry. The effects of sample elemental composition, density and geometry were discussed in detail and calculated in terms of efficiency correction factors. The effect of sample placement was also analyzed, the results indicate that the radioactive nuclides and sample density are not absolutely uniform distributed along the axial direction. At last, a unified binary quadratic functional relationship of efficiency correction factors as a function of sample density and height was obtained by the least square fitting method. This function covers the sample density and height range of 0.8-1.8 g/cm(3) and 3.0-7.25 cm, respectively. The efficiency correction factors calculated by the fitted function are in good agreement with those obtained by the GEANT4 simulations with the determination coefficient value greater than 0.9999. The results obtained in this paper make the above-mentioned relative measurements more accurate and efficient in the routine radioactive analysis of environmental cylindrical soil samples. PMID:25973538

  16. The Watchman Detector Design

    NASA Astrophysics Data System (ADS)

    Dazeley, Steven

    2014-03-01

    The Watchman collaboration is proposing a kiloton scale antineutrino detector of reactor-based antineutrinos for non-proliferation purposes. As an added bonus the detector will also have the capability to search for evidence of sterile neutrino oscillation, super-nova antineutrinos and, in a second phase, measure the neutrino mass hierarchy. Despite that fact that KamLAND demonstrated the feasibility of kiloton scale, long distance antineutrino detection with liquid scintillator, similar detectors at the megaton scale remain problematic for environmental, cost and light attenuation reasons. Water, with gadolinium added for neutron sensitivity, may be the detection medium of choice if its efficiency can be shown to be competitive with scintillator. The goal of the Watchman project, therefore, is to demonstrate medium distance reactor antineutrino detection, and thus demonstrate the feasibility of moving to water-based megaton scale antineutrino detectors in the future. In this talk I will describe the scope of the experiment, the physics and engineering challenges involved, the proposed design and the predicted performance of the experimental non-proliferation and high-energy physics program. Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy, National Nuclear Security Administration under Contract DE-AC52-07NA27344. Release number LLNL-ABS-648381.

  17. Terahertz sources and detectors

    NASA Astrophysics Data System (ADS)

    Crowe, Thomas W.; Porterfield, David W.; Hesler, Jeffrey L.; Bishop, William L.; Kurtz, David S.; Hui, Kai

    2005-05-01

    Through the support of the US Army Research Office we are developing terahertz sources and detectors suitable for use in the spectroscopy of chemical and biological materials as well as for use in imaging systems to detect concealed weapons. Our technology relies on nonlinear diodes to translate the functionality achieved at microwave frequencies to the terahertz band. Basic building blocks that have been developed for this application include low-noise mixers, frequency multipliers, sideband generators and direct detectors. These components rely on planar Schottky diodes and integrated diode circuits and are therefore easy to assemble and robust. They require no mechanical tuners to achieve high efficiency and broad bandwidth. This paper will review the range of performance that has been achieved with these terahertz components and briefly discuss preliminary results achieved with a spectroscopy system and the development of sources for imaging systems.

  18. Physics and Detector Response Simulations

    NASA Astrophysics Data System (ADS)

    Graf, Norman A.; McCormick, Jeremy

    As the complexity and resolution of modern detectors increases, the need for detailed simulation of the experimental setup also becomes more important. Designing detector systems composed of many disparate subsystems requires efficient tools to simulate the detector response and reconstruct the events. Comparisons of different technology options, or geometric layouts, are facilitated if the results can be obtained with a common simulation and reconstruction framework. We have developed efficient and flexible tools for detailed physics and detector response simulation as well as event reconstruction and analysis. The primary goal has been to develop a software toolkit and computing infrastructure to allow physicists from universities and labs to quickly and easily conduct physics analyses and contribute to detector research and development with a minimal investment of time and effort. The application harnesses the full power of the Geant4 toolkit without requiring the end user to have any experience with either Geant4 or C++, thereby allowing the user to concentrate on the physics of the detector system. The reconstruction software and analysis environment are written in Java, providing a modern, object-oriented platform which is independent of the computing operating system.

  19. Long-range alpha detector

    SciTech Connect

    MacArthur, D.W.; McAtee, J.L. )

    1991-01-01

    Historically, alpha-particle and alpha-contamination detectors have been limited by the very short range of alpha particles in air and by relatively poor sensitivity even if the particles are intercepted. Alpha detectors have had to be operated in a vacuum or in close proximity to the source if reasonable efficiency is desired. Alpha particles interact with the ambient air, producing ionization in the air at the rate of {approximately}30,000 ion pairs per mega-electron-volt of alpha energy. These charges can be transported over significant distances (several meters) in a moving current of air generated by a small fan. An ion chamber located in front of the fan measures the current carried by the moving ions. The long-range alpha detector (LRAD) offers several advantages over more traditional alpha detectors. First and foremost, it can operate efficiently even if the contamination is not easily accessible. Second, ions generated by contamination in crevices and other unmonitorable locations can be detected if the airflow penetrates those areas. Third, all of the contamination on a large surface will generate ions that can be detected in a single detector; hence, the detector's sensitivity to distributed sources is not limited by the size of the probe. Finally, a simple ion chamber can detect very small electric currents, making this technique potentially quite sensitive.

  20. Flame Detector

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Scientific Instruments, Inc. has now developed a second generation, commercially available instrument to detect flames in hazardous environments, typically refineries, chemical plants and offshore drilling platforms. The Model 74000 detector incorporates a sensing circuit that detects UV radiation in a 100 degree conical field of view extending as far as 250 feet from the instrument. It operates in a bandwidth that makes it virtually 'blind' to solar radiation while affording extremely high sensitivity to ultraviolet flame detection. A 'windowing' technique accurately discriminates between background UV radiation and ultraviolet emitted from an actual flame, hence the user is assured of no false alarms. Model 7410CP is a combination controller and annunciator panel designed to monitor and control as many as 24 flame detectors. *Model 74000 is no longer being manufactured.

  1. Neutrino Detectors

    NASA Astrophysics Data System (ADS)

    von Feilitzsch, Franz; Lanfranchi, Jean-Côme; Wurm, Michael

    The neutrino was postulated by Wolfgang Pauli in the early 1930s, but could only be detected for the first time in the 1950s. Ever since scientists all around the world have worked on the detection and understanding of this particle which so scarcely interacts with matter. Depending on the origin and nature of the neutrino, various types of experiments have been developed and operated. In this entry, we will review neutrino detectors in terms of neutrino energy and associated detection technique as well as the scientific outcome of some selected examples. After a brief historical introduction, the detection of low-energy neutrinos originating from nuclear reactors or from the Earth is used to illustrate the principles and difficulties which are encountered in detecting neutrinos. In the context of solar neutrino spectroscopy, where the neutrino is used as a probe for astrophysics, three different types of neutrino detectors are presented - water ?erenkov, radiochemical, and liquid-scintillator detectors. Moving to higher neutrino energies, we discuss neutrinos produced by astrophysical sources and from accelerators. The entry concludes with an overview of a selection of future neutrino experiments and their scientific goals.

  2. SuperCDMS Detector Fabrication Advances

    NASA Astrophysics Data System (ADS)

    Brink, P. L.; Ahmed, Z.; Akerib, D. S.; Bailey, C. N.; Balakishiyeva, D.; Bauer, D. A.; Beaty, J.; Bunker, R.; Cabrera, B.; Caldwell, D. O.; Cooley, J.; do Couto e Silva, E.; Cushman, P.; Daal, M.; DeJongh, F.; Dragowsky, M. R.; Duong, L.; Figueroa-Feliciano, E.; Filippini, J.; Fritts, M.; Golwala, S. R.; Grant, D. R.; Hall, J.; Hennings-Yeomans, R.; Hertel, S.; Hojem, A.; Holmgren, D.; Hsu, L.; Huber, M. E.; Irwin, K. D.; Kamaev, O.; Kos, M.; Kiveni, M.; Leman, S. W.; Mahapatra, R.; Mandic, V.; McCarthy, K. A.; Moore, D.; Mirabolfathi, N.; Nelson, H.; Novak, L.; Ogburn, R. W.; Pyle, M.; Qiu, X.; Ramberg, E.; Rau, W.; Reisetter, A.; Saab, T.; Sadoulet, B.; Sander, J.; Schmitt, R.; Schnee, R. W.; Seitz, D. N.; Serfass, B.; Sundqvist, K. M.; Tomada, A.; Wang, G.; Wikus, P.; Yellin, S.; Yoo, J.; Young, B. A.

    2009-12-01

    For its dark matter search the SuperCDMS collaboration has developed new Ge detectors using the same athermal phonon sensors and ionization measurement technology of CDMS II but with larger mass, superior sensor performance and increased fabrication efficiency. The improvements in fabrication are described, a comparison of CDMS II and SuperCDMS detector production yield is reported, and future scalability addressed.

  3. Detector requirements for space infrared astronomy

    NASA Technical Reports Server (NTRS)

    Wright, E. L.

    1986-01-01

    Requirements for background-limited (BLIP) detectors are discussed in terms of number of photons falling on each pixel, dark current, high detective quantum efficiencies, large numbers of pixels, and array size.

  4. Flexible composite radiation detector

    DOEpatents

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

    2006-12-05

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

  5. Pillar Structured Thermal Neutron Detector

    SciTech Connect

    Nikolic, R; Conway, A; Reinhardt, C; Graff, R; Wang, T; Deo, N; Cheung, C

    2008-06-10

    This work describes an innovative solid state device structure that leverages advanced semiconductor fabrication technology to produce an efficient device for thermal neutron detection which we have coined the 'Pillar Detector'. State-of-the-art thermal neutron detectors have shortcomings in simultaneously achieving high efficiency, low operating voltage while maintaining adequate fieldability performance. By using a three dimensional silicon PIN diode pillar array filled with isotopic {sup 10}boron ({sup 10}B), a high efficiency device is theoretically possible. Here we review the design considerations for going from a 2-D to 3-D device and discuss the materials trade-offs. The relationship between the geometrical features and efficiency within our 3-D device is investigated by Monte Carlo radiation transport method coupled with finite element drift-diffusion carrier transport simulations. To benchmark our simulations and validate the predicted efficiency scaling, experimental results of a prototype device are illustrated. The fabricated pillar structures reported in this work are composed of 2 {micro}m diameter silicon pillars with a 2 {micro}m spacing and pillar height of 12 {micro}m. The pillar detector with a 12 {micro}m height achieved a thermal neutron detection efficiency of 7.3% at a reverse bias of -2 V.

  6. Ion detector

    DOEpatents

    Tullis, Andrew M. (Livermore, CA)

    1987-01-01

    An improved ion detector device of the ionization detection device chamber ype comprises an ionization chamber having a central electrode therein surrounded by a cylindrical electrode member within the chamber with a collar frictionally fitted around at least one of the electrodes. The collar has electrical contact means carried in an annular groove in an inner bore of the collar to contact the outer surface of the electrode to provide electrical contact between an external terminal and the electrode without the need to solder leads to the electrode.

  7. High efficiency photodetection below the quantum noise limit

    E-print Network

    Bullard, Elizabeth Caryn

    2005-01-01

    Two low-noise, high quantum efficiency, high bandwidth photodetectors have constructed to form a balanced homodyne detector to detect squeezed light. The detectors have quantum efficiencies of 85% and 90%, a bandwidth of ...

  8. Advanced Thermal Neutron Detectors

    NASA Astrophysics Data System (ADS)

    Smith, Graham; Fried, Jack; de Geronimo, Gianluigi; Mahler, George; Makowiecki, Don; Mead, Joe; Radeka, Veljko; Schaknowski, Neil; Vernon, Emerson; Yu, Bo

    2012-02-01

    With the advent of new high intensity spallation sources, there is a vital need for development of advanced position sensitive detectors. Using neutron conversion in helium 3, which yields a large signal with excellent background rejection capability, our research program focuses on improving the rate capability, resolution, efficiency and long term stability of detectors for neutron scattering studies. We have developed a suite of detectors using proportional chambers, the latest being an array of curved, multi-wire segments with interpolating cathode strip electrodes operating simultaneously and seamlessly in a single gas volume. With rate capability of nearly 1 million per sec, this instrument has significantly advanced the state-of-the-art for protein crystallography. To attain even higher count rates, a new concept based on operation in the ionization mode is being explored, in which direct ionization from a neutron conversion is collected with unity gain on one of many pads that form the anode plane. Each pad is implemented with charge sensitive electronics, using purpose-designed application specific integrated circuits. A prototype device with 48 by 48 pads has been successfully developed. Examples of measurements at major neutron user facilities will be presented.

  9. Neutron detector characterization for SCINTIA array

    SciTech Connect

    Matei, C.; Hambsch, F. J.; Oberstedt, S.

    2011-07-01

    SCINTIA is a new detector array of organic scintillators under development at the Inst. for Reference Materials and Measurements (IRMM). The present design of SCINTIA includes NE213, p-terphenyl and Li glass neutron detectors positioned in a spherical configuration around the target. The properties of a novel p-terphenyl neutron detector to be used with SCINTIA have been investigated using photon sources and neutrons from a time tagged {sup 252}Cf(sf) source. The results show that the p-terphenyl crystal has better energy resolution, increased proton light output and neutron efficiency when compared to a similar size NE213 equivalent neutron detector. (authors)

  10. Efficiency corrections in low-energy gamma spectrometry

    NASA Astrophysics Data System (ADS)

    Isakar, K.; Realo, K.; Kiisk, M.; Realo, E.

    2007-09-01

    In HPGe gamma spectrometric analysis of 210Pb in aerosol filter samples, the activity concentrations were corrected for self-attenuation and sample heights. Corrections were evaluated using the Monte Carlo simulation toolkit Geant4 and the Gespecor software. Calculations were made for 46.5 keV gamma line of 210Pb in Petryanoff (FPP) and fiberglass aerosol filters of varying heights. The IAEA RGU-1 reference material of different heights in a similar beaker served as a standard source. As a result, the approximations were found to calculate corrected efficiencies for samples with different heights. The method was applied for the study of 210Pb content in air in Estonia.

  11. Oscillator detector

    SciTech Connect

    Potter, B.M.

    1980-05-13

    An alien liquid detector employs a monitoring element and an oscillatory electronic circuit for maintaining the temperature of the monitoring element substantially above ambient temperature. The output wave form, eg., frequency of oscillation or wave shape, of the oscillatory circuit depends upon the temperaturedependent electrical characteristic of the monitoring element. A predetermined change in the output waveform allows water to be discriminated from another liquid, eg., oil. Features of the invention employing two thermistors in two oscillatory circuits include positioning one thermistor for contact with water and the other thermistor above the oil-water interface to detect a layer of oil if present. Unique oscillatory circuit arrangements are shown that achieve effective thermistor action with an economy of parts and energizing power. These include an operational amplifier employed in an astable multivibrator circuit, a discrete transistor-powered tank circuit, and use of an integrated circuit chip.

  12. Nuclear resonance fluorescence in U-238 using LaBr detectors for nuclear security

    NASA Astrophysics Data System (ADS)

    Hayakawa, Takehito; Negm, Hani; Ohgaki, Hideaki; Daito, Izuru; Kii, Toshiteru; Zen, Heishun; Omer, Mohamed; Shizuma, Toshiyuki; Hajima, Ryoichi

    2014-09-01

    Recently, a nondestructive measurement method of shielded fissional isotopes such as 235U or 239Pu has been proposed for the nuclear security. These isotopes are measured by using nuclear resonance fluorescence (NRF) with monochromatic energy gamma-ray beams generated by laser Compton-scattering (LCS). We have proposed that one measure scattered gamma-rays from NRF with LCS gamma-ray beams using the LaBr3(Ce) detectors. The LaBr3(Ce) crystals include internal radioisotopes of a meta-stable isotope 138La and alpha decay chains from some actinides as 227Ac. There is a broad pump at about 2 MeV. This pump is considered to be an overlap of alpha-rays from decay chains of some actinides but its detailed structure has not been established. Here we have measured NRF spectra of 238U using the LCS gamma-rays with energy of about 2.5 MeV at the HIgS facility of the Duke University. The background has been evaluated using a simulation code GEAT4. The 9 peaks, 8 NRF gamma-rays plus the Compton scattered gamma-ray of the incident beam, are finally assigned in an energy range of about 200 keV at about 2.5 MeV. The 8 integrated NRF cross-sections measured by LaBr3(Ce) have been consistent with results by an HPGe detector. The three levels are newly assigned using the HPGe detector. Two of them are also measured by LaBr3(Ce).

  13. Microradiography with Semiconductor Pixel Detectors

    NASA Astrophysics Data System (ADS)

    Jakubek, Jan; Cejnarova, Andrea; Dammer, Ji?í; Holý, Tomáš; Platkevi?, Michal; Pospíšil, Stanislav; Vav?ík, Daniel; Vykydal, Zden?k

    2007-11-01

    High resolution radiography (with X-rays, neutrons, heavy charged particles, …) often exploited also in tomographic mode to provide 3D images stands as a powerful imaging technique for instant and nondestructive visualization of fine internal structure of objects. Novel types of semiconductor single particle counting pixel detectors offer many advantages for radiation imaging: high detection efficiency, energy discrimination or direct energy measurement, noiseless digital integration (counting), high frame rate and virtually unlimited dynamic range. This article shows the application and potential of pixel detectors (such as Medipix2 or TimePix) in different fields of radiation imaging.

  14. Future of Semiconductor Based Thermal Neutron Detectors

    SciTech Connect

    Nikolic, R J; Cheung, C L; Reinhardt, C E; Wang, T F

    2006-02-22

    Thermal neutron detectors have seen only incremental improvements over the last decades. In this paper we overview the current technology of choice for thermal neutron detection--{sup 3}He tubes, which suffer from, moderate to poor fieldability, and low absolute efficiency. The need for improved neutron detection is evident due to this technology gap and the fact that neutrons are a highly specific indicator of fissile material. Recognizing this need, we propose to exploit recent advances in microfabrication technology for building the next generation of semiconductor thermal neutron detectors for national security requirements, for applications requiring excellent fieldability of small devices. We have developed an innovative pathway taking advantage of advanced processing and fabrication technology to produce the proposed device. The crucial advantage of our Pillar Detector is that it can simultaneously meet the requirements of high efficiency and fieldability in the optimized configuration, the detector efficiency could be higher than 70%.

  15. Southwest Research Institute intensified detector development capability

    NASA Astrophysics Data System (ADS)

    Wilkinson, Erik; Vincent, Michael; Kofoed, Christopher; Andrews, John; Brownsberger, Judith; Siegmund, Oswald

    2012-09-01

    Imaging detectors for wavelengths between 10 nm and 105 nm generally rely on microchannel plates (MCPs) to provide photon detection (via the photo-electric effect) and charge amplification. This is because silicon-based detectors (CCD or APS) have near zero quantum detection efficiency (QDE) over this wavelength regime. Combining a MCP based intensifier tube with a silicon detector creates a detector system that can be tuned to the wavelength regime of interest for a variety of applications. Intensified detectors are used in a variety of scientific (e.g. Solar Physics) and commercial applications (spectroscopic test instrumentation, night vision goggles, low intensity cameras, etc.). Building an intensified detector requires the mastery of a variety of technologies involved in integrating and testing of these detector systems. We report on an internally funded development program within the Southwest Research Institute to architect, design, integrate, and test intensified imaging detectors for space-based applications. Through a rigorous hardware program the effort is developing and maturing the technologies necessary to build and test a large format (2k × 2k) UV intensified CCD detector. The intensified CCD is designed around a commercially available CCD that is optically coupled to a UV Intensifier Tube from Sensor Sciences, LLC. The program aims to demonstrate, through hardware validation, the ability to architect and execute the integration steps necessary to produce detector systems suitable for space-based applications.

  16. Microwave characteristics of GaAs MMIC integratable optical detectors

    NASA Technical Reports Server (NTRS)

    Claspy, Paul C.; Hill, Scott M.; Bhasin, Kul B.

    1989-01-01

    Interdigitated photoconductive detectors were fabricated on microwave device structures, making them easily integratable with Monolithic Microwave Integrated Circuits (MMIC). Detector responsivity as high as 2.5 A/W and an external quantum efficiency of 3.81 were measured. Response speed was nearly independent of electrode geometry, and all detectors had usable response at frequencies to 6 GHz. A small signal model of the detectors based on microwave measurements was also developed.

  17. Large-Mass Ultra-Low Noise Germanium Detectors: Performance and Applications in Neutrino and Astroparticle Physics

    E-print Network

    P. S. Barbeau; J. I. Collar; O. Tench

    2007-01-07

    A new type of radiation detector, a p-type modified electrode germanium diode, is presented. The prototype displays, for the first time, a combination of features (mass, energy threshold and background expectation) required for a measurement of coherent neutrino-nucleus scattering in a nuclear reactor experiment. The device hybridizes the mass and energy resolution of a conventional HPGe coaxial gamma spectrometer with the low electronic noise and threshold of a small x-ray semiconductor detector, also displaying an intrinsic ability to distinguish multiple from single-site particle interactions. The present performance of the prototype and possible further improvements are discussed, as well as other applications for this new type of device in neutrino and astroparticle physics (double-beta decay, neutrino magnetic moment and WIMP searches).

  18. Important detector parameters: 1. Quantum efficiency

    E-print Network

    Peletier, Reynier

    photography dominated astronomical detection for more than a century: ~1870-1980 pro's and con of photography first sky object photographs (daguerrotypes): 1840 Moon J.W. Draper 1843 Solar spectrum ,, 1845 Sun Foucault +Fizeau 1870 invention of dry gelatine emulsions this enabled astronomical applications

  19. SU-E-I-62: Assessing Radiation Dose Reduction and CT Image Optimization Through the Measurement and Analysis of the Detector Quantum Efficiency (DQE) of CT Images Using Different Beam Hardening Filters

    SciTech Connect

    Collier, J; Aldoohan, S; Gill, K

    2014-06-01

    Purpose: Reducing patient dose while maintaining (or even improving) image quality is one of the foremost goals in CT imaging. To this end, we consider the feasibility of optimizing CT scan protocols in conjunction with the application of different beam-hardening filtrations and assess this augmentation through noise-power spectrum (NPS) and detector quantum efficiency (DQE) analysis. Methods: American College of Radiology (ACR) and Catphan phantoms (The Phantom Laboratory) were scanned with a 64 slice CT scanner when additional filtration of thickness and composition (e.g., copper, nickel, tantalum, titanium, and tungsten) had been applied. A MATLAB-based code was employed to calculate the image of noise NPS. The Catphan Image Owl software suite was then used to compute the modulated transfer function (MTF) responses of the scanner. The DQE for each additional filter, including the inherent filtration, was then computed from these values. Finally, CT dose index (CTDIvol) values were obtained for each applied filtration through the use of a 100 mm pencil ionization chamber and CT dose phantom. Results: NPS, MTF, and DQE values were computed for each applied filtration and compared to the reference case of inherent beam-hardening filtration only. Results showed that the NPS values were reduced between 5 and 12% compared to inherent filtration case. Additionally, CTDIvol values were reduced between 15 and 27% depending on the composition of filtration applied. However, no noticeable changes in image contrast-to-noise ratios were noted. Conclusion: The reduction in the quanta noise section of the NPS profile found in this phantom-based study is encouraging. The reduction in both noise and dose through the application of beam-hardening filters is reflected in our phantom image quality. However, further investigation is needed to ascertain the applicability of this approach to reducing patient dose while maintaining diagnostically acceptable image qualities in a clinical setting.

  20. Detector simulation needs for detector designers

    SciTech Connect

    Hanson, G.G.

    1987-11-01

    Computer simulation of the components of SSC detectors and of the complete detectors will be very important for the designs of the detectors. The ratio of events from interesting physics to events from background processes is very low, so detailed understanding of detector response to the backgrounds is needed. Any large detector for the SSC will be very complex and expensive and every effort must be made to design detectors which will have excellent performance and will not have to undergo major rebuilding. Some areas in which computer simulation is particularly needed are pattern recognition in tracking detectors and development of shower simulation code which can be trusted as an aid in the design and optimization of calorimeters, including their electron identification performance. Existing codes require too much computer time to be practical and need to be compared with test beam data at energies of several hundred GeV. Computer simulation of the processing of the data, including electronics response to the signals from the detector components, processing of the data by microprocessors on the detector, the trigger, and data acquisition will be required. In this report we discuss the detector simulation needs for detector designers.

  1. Detector developments at DESY.

    PubMed

    Wunderer, Cornelia B; Allahgholi, Aschkan; Bayer, Matthias; Bianco, Laura; Correa, Jonathan; Delfs, Annette; Göttlicher, Peter; Hirsemann, Helmut; Jack, Stefanie; Klyuev, Alexander; Lange, Sabine; Marras, Alessandro; Niemann, Magdalena; Pithan, Florian; Reza, Salim; Sheviakov, Igor; Smoljanin, Sergej; Tennert, Maximilian; Trunk, Ulrich; Xia, Qingqing; Zhang, Jiaguo; Zimmer, Manfred; Das, Dipayan; Guerrini, Nicola; Marsh, Ben; Sedgwick, Iain; Turchetta, Renato; Cautero, Giuseppe; Giuressi, Dario; Menk, Ralf; Khromova, Anastasiya; Pinaroli, Giovanni; Stebel, Luigi; Marchal, Julien; Pedersen, Ulrik; Rees, Nick; Steadman, Paul; Sussmuth, Mark; Tartoni, Nicola; Yousef, Hazem; Hyun, HyoJung; Kim, KyungSook; Rah, Seungyu; Dinapoli, Roberto; Greiffenberg, Dominic; Mezza, Davide; Mozzanica, Aldo; Schmitt, Bernd; Shi, Xintian; Krueger, Hans; Klanner, Robert; Schwandt, Joem; Graafsma, Heinz

    2016-01-01

    With the increased brilliance of state-of-the-art synchrotron radiation sources and the advent of free-electron lasers (FELs) enabling revolutionary science with EUV to X-ray photons comes an urgent need for suitable photon imaging detectors. Requirements include high frame rates, very large dynamic range, single-photon sensitivity with low probability of false positives and (multi)-megapixels. At DESY, one ongoing development project - in collaboration with RAL/STFC, Elettra Sincrotrone Trieste, Diamond, and Pohang Accelerator Laboratory - is the CMOS-based soft X-ray imager PERCIVAL. PERCIVAL is a monolithic active-pixel sensor back-thinned to access its primary energy range of 250?eV to 1?keV with target efficiencies above 90%. According to preliminary specifications, the roughly 10?cm × 10?cm, 3.5k × 3.7k monolithic sensor will operate at frame rates up to 120?Hz (commensurate with most FELs) and use multiple gains within 27?ľm pixels to measure 1 to ?100000 (500?eV) simultaneously arriving photons. DESY is also leading the development of the AGIPD, a high-speed detector based on hybrid pixel technology intended for use at the European XFEL. This system is being developed in collaboration with PSI, University of Hamburg, and University of Bonn. The AGIPD allows single-pulse imaging at 4.5?MHz frame rate into a 352-frame buffer, with a dynamic range allowing single-photon detection and detection of more than 10000 photons at 12.4?keV in the same image. Modules of 65k pixels each are configured to make up (multi)megapixel cameras. This review describes the AGIPD and the PERCIVAL concepts and systems, including some recent results and a summary of their current status. It also gives a short overview over other FEL-relevant developments where the Photon Science Detector Group at DESY is involved. PMID:26698052

  2. Spiral silicon drift detectors

    SciTech Connect

    Rehak, P.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Lutz, G.; Kemmer, J.; Prechtel, U.; Ziemann, T.

    1988-01-01

    An advanced large area silicon photodiode (and x-ray detector), called Spiral Drift Detector, was designed, produced and tested. The Spiral Detector belongs to the family of silicon drift detectors and is an improvement of the well known Cylindrical Drift Detector. In both detectors, signal electrons created in silicon by fast charged particles or photons are drifting toward a practically point-like collection anode. The capacitance of the anode is therefore kept at the minimum (0.1pF). The concentric rings of the cylindrical detector are replaced by a continuous spiral in the new detector. The spiral geometry detector design leads to a decrease of the detector leakage current. In the spiral detector all electrons generated at the silicon-silicon oxide interface are collected on a guard sink rather than contributing to the detector leakage current. The decrease of the leakage current reduces the parallel noise of the detector. This decrease of the leakage current and the very small capacities of the detector anode with a capacitively matched preamplifier may improve the energy resolution of Spiral Drift Detectors operating at room temperature down to about 50 electrons rms. This resolution is in the range attainable at present only by cooled semiconductor detectors. 5 refs., 10 figs.

  3. Development of {gamma}-ray detectors for {sup 16}O(p,p'{gamma}) experiment

    SciTech Connect

    Mori, T.; Izumi, T.; Ou, I.; Yano, T.; Sakuda, M.; Tamii, A.; Suzuki, T.; Yosoi, M.

    2012-11-12

    The {gamma} ray production in neutral-current (NC) neutrino-oxygen interaction is very important to the detection of neutrinos from supernova explosion in a neutrino experiment, since those {gamma} rays can become extra signals or unexpected background in the energy region from 5 MeV to 30 MeV. We propose the experiment to measure {gamma} rays in {sup 16}O(p,p') reaction at Research Center for Nuclear Physics (RCNP, Osaka) to provide good information on the {gamma}-ray emission spectra in neutrino-oxygen reactions. We present the design of {gamma}-ray detectors (NaI, CsI, HPGe), which will be used in proposed experiment.

  4. Neutron spectrometer for ITER using silicon detectors

    SciTech Connect

    Conroy, Sean W.; Weiszflog, Matthias; Andersson-Sunden, Erik; Ericsson, Goran; Gatu-Johnson, Maria; Hellesen, Carl; Ronchi, Emanuel; Sjostrand, Henrik

    2008-10-15

    High resolution neutron spectrometers provide information about plasma parameters at existing fusion experiments. Such a system may also be employed at ITER. Proton recoil telescopes have classically been used to detect neutrons with good energy resolution but poor efficiency. Using annular silicon detectors, it is possible to greatly increase the solid angle coverage and hence improve efficiency. Based on a simulation (MCNPX) study, the scaling of energy resolution, efficiency, and time to determine an ion temperature to 10% accuracy on foil thickness and detector location is shown. The latter quantity is used to determine the optimum foil thickness and detector geometry for specific plasma temperatures. For a 20 keV deuterium-tritium (DT) plasma, 5.3% resolution with efficiency of 2.9x10{sup -4} n cm{sup 2} is attainable using the available detectors. This gives a temperature measurement with 10% accuracy in 1.1 ms for a neutron flux of 2x10{sup 9} n cm{sup -2}. Multiple detectors can be used to further increase the efficiency if needed. A system of this kind could be tested in a future DT campaign at, for example, JET.

  5. Large area liquid argon detectors for interrogation systems

    SciTech Connect

    Gary, Charles; Kane, Steve; Firestone, Murray I.; Smith, Gregory; Gozani, Tsahi; Brown, Craig; Kwong, John; King, Michael J.; Nikkel, James A.; McKinsey, Dan

    2013-04-19

    Measurements of the efficiency, pulse shape, and energy and time resolution of liquid argon (LAr) detectors are presented. Liquefied noble gas-based (LNbG) detectors have been developed for the detection of dark matter and neutrinoless double-beta decay. However, the same qualities that make LNbG detectors ideal for these applications, namely their size, cost, efficiency, pulse shape discrimination and resolution, make them promising for portal screening and the detection of Special Nuclear Materials (SNM). Two 18-liter prototype detectors were designed, fabricated, and tested, one with pure LAr and the other doped with liquid Xe (LArXe). The LArXe detector presented the better time and energy resolution of 3.3 ns and 20% at 662 KeV, respectively. The total efficiency of the detector was measured to be 35% with 4.5% of the total photons detected in the photopeak.

  6. Photoelectron yield in the prototype of the liquid argon detector for CDEX-10

    E-print Network

    Chen, Qing-Hao; Cheng, Jian-Ping; Kang, Ke-Jun; Li, Yuan-Jing; Lin, Shin-Ted; Tang, Chang-Jian; Xing, Hao-Yang; Yu, Xun-Zhen; Zeng, Ming

    2015-01-01

    The China Dark Matter Experiment (CDEX) is a low background experiment at China Jinping Underground Laboratory (CJPL) designed to directly detect dark matter with a high-purity germanium (HPGe) detector. In the second phase CDEX-10 with 10 kg germanium array detector system, the liquid argon (LAr) anti-Compton active shielding and cooling system is proposed. For purpose of studying the properties of LAr detector, a prototype with an active volume of 7 liters of liquid argon was built and operated. The photoelectron yields, as a critically important parameter for the LAr detector, have been measured to be 0.051-0.079 p.e./keV for 662 keV gamma lines at different positions. The good agreement between the experimental and simulation results has provided a quite reasonable understanding and determination of the important parameters such as the Surviving Fraction of the $Ar_{2}^{*}$ excimers, the absorption length for 128 nm photons in liquid argon, the reflectivity of Teflon and so on.

  7. Photoelectron yield in the prototype of the liquid argon detector for CDEX-10

    E-print Network

    Qing-Hao Chen; Qian Yue; Jian-Ping Cheng; Ke-Jun Kang; Yuan-Jing Li; Shin-Ted Lin; Chang-Jian Tang; Hao-Yang Xing; Xun-Zhen Yu; Ming Zeng

    2015-12-14

    The China Dark Matter Experiment (CDEX) is a low background experiment at China Jinping Underground Laboratory (CJPL) designed to directly detect dark matter with a high-purity germanium (HPGe) detector. In the second phase CDEX-10 with 10 kg germanium array detector system, the liquid argon (LAr) anti-Compton active shielding and cooling system is proposed. For purpose of studying the properties of LAr detector, a prototype with an active volume of 7 liters of liquid argon was built and operated. The photoelectron yields, as a critically important parameter for the LAr detector, have been measured to be 0.051-0.079 p.e./keV for 662 keV gamma lines at different positions. The good agreement between the experimental and simulation results has provided a quite reasonable understanding and determination of the important parameters such as the Surviving Fraction of the $Ar_{2}^{*}$ excimers, the absorption length for 128 nm photons in liquid argon, the reflectivity of Teflon and so on.

  8. Photoconductors for X-Ray Image Detectors

    NASA Astrophysics Data System (ADS)

    Kabir, M.; Kasap, Safa; Rowlands, John

    Recent flat-panel X-ray imaging detectors have been shown to be able to replace present-day X-ray film/screen cassettes; they capture an X-ray image electronically and hence enable a clinical transition to digital radiography. This chapter critically discusses the material, transport and imaging detector properties (e.g., dark current) of several potential X-ray photoconductors and compares them with an ideal photoconductor for use in direct-conversion imaging detectors. The present chapter also considers various metrics of detector performances including sensitivity, detective quantum efficiency, resolution in terms of the modulation transfer function, image lag and ghosting; and examines how these metrics depend on the photoconductor, and detector structure and design.

  9. Detectors don’t fear neutrons

    E-print Network

    Del Rosso, A

    2013-01-01

    High-intensity pulsed neutron fields are produced at particle accelerators such as CERN’s PS and LHC. The efficient detection of this stray pulsed radiation is technically difficult and standard detectors show strong limitations when measuring such fields. A new test performed at the HiRadMat facility has recently shed light on the performance of various neutron detectors exposed to extreme conditions.

  10. Single photon detector with high polarization sensitivity

    PubMed Central

    Guo, Qi; Li, Hao; You, LiXing; Zhang, WeiJun; Zhang, Lu; Wang, Zhen; Xie, XiaoMing; Qi, Ming

    2015-01-01

    Polarization is one of the key parameters of light. Most optical detectors are intensity detectors that are insensitive to the polarization of light. A superconducting nanowire single photon detector (SNSPD) is naturally sensitive to polarization due to its nanowire structure. Previous studies focused on producing a polarization-insensitive SNSPD. In this study, by adjusting the width and pitch of the nanowire, we systematically investigate the preparation of an SNSPD with high polarization sensitivity. Subsequently, an SNSPD with a system detection efficiency of 12% and a polarization extinction ratio of 22 was successfully prepared. PMID:25875225

  11. Operation and performance of new NIR detectors from SELEX

    NASA Astrophysics Data System (ADS)

    Atkinson, D.; Bezawada, N.; Hipwood, L. G.; Shorrocks, N.; Milne, H.

    2012-07-01

    The European Space Agency (ESA) has funded SELEX Galileo, Southampton, UK to develop large format near infrared (NIR) detectors for its future space and ground based programmes. The UKATC has worked in collaboration with SELEX Galileo to test and characterise the new detectors produced during phase-1 of the development. In order to demonstrate the detector material performance, the HgCdTe (MCT) detector diodes (grown on GaAs substrate through MOVPE process in small 320×256, 24?m pixel format) are hybridised to the existing SELEX Galileo SWALLOW CMOS readout chip. The substrate removed and MCT thinned detector arrays were then tested and evaluated at the UKATC following screening tests at SELEX. This paper briefly describes the test setup, the operational aspects of the readout multiplexer and presents the performance parameters of the detector arrays including: conversion gain, detector dark current, read noise, linearity, quantum efficiency and persistence for various detector temperatures between 80K and 140K.

  12. Noise performance of the D0 layer 0 silicon detector

    SciTech Connect

    Johnson, M.; /Fermilab

    2006-11-01

    A new inner detector called Layer 0 has been added to the existing silicon detector for the DZero colliding beams experiment. This detector has an all carbon fiber support structure that employs thin copper clad Kapton sheets embedded in the surface of the carbon fiber structure to improve the grounding of the structure and a readout system that fully isolates the local detector ground from the rest of the detector. Initial measurements show efficiencies greater than 90% and 0.3 ADC count common mode contribution to the signal noise.

  13. Microstructured silicon neutron detectors for security applications

    NASA Astrophysics Data System (ADS)

    Esteban, S.; Fleta, C.; Guardiola, C.; Jumilla, C.; Pellegrini, G.; Quirion, D.; Rodriguez, J.; Lozano, M.

    2014-12-01

    In this paper we present the design and performance of a perforated thermal neutron silicon detector with a 6LiF neutron converter. This device was manufactured within the REWARD project workplace whose aim is to develop and enhance technologies for the detection of nuclear and radiological materials. The sensor perforated structure results in a higher efficiency than that obtained with an equivalent planar sensor. The detectors were tested in a thermal neutron beam at the nuclear reactor at the Instituto Superior Técnico in Lisbon and the intrinsic detection efficiency for thermal neutrons and the gamma sensitivity were obtained. The Geant4 Monte Carlo code was used to simulate the experimental conditions, i.e. thermal neutron beam and the whole detector geometry. An intrinsic thermal neutron detection efficiency of 8.6%ą0.4% with a discrimination setting of 450 keV was measured.

  14. The ANTARES detector: background sources and effects on detector performance

    E-print Network

    ANTARES Collaboration; S. Escoffier

    2007-10-02

    The ANTARES Collaboration is deploying a large neutrino detector at a depth of 2475 m in the Mediterranean Sea, 40 km off shore from La Seyne-sur-Mer in South France. The construction of this 12-line detector with 75 phototubes per line will be completed early 2008. Data taking has begun since April 2005 with an instrumentation line also equipped with optical modules. The first 5 detector lines are operational since January 2007. The telescope is aimed to observe high energy cosmic neutrinos through the detection of the Cerenkov light produced by up-going induced muons. Background sources are due to atmospheric neutrinos as well as misreconstructed atmospheric muons. Additional backgrounds inherent to the sea water environment come from 40K decay and marine organisms' luminescence. While the contribution of the former is expected to be constant at a level of about 45 kHz, the bioluminescence has shown large time variations, with periods of very high activity, up to several hundred kHz. Description of these background sources will be reported, and effects on detector performance will be described. Methods recently developed to improve the detection efficiency in high background periods will be described, together with some of the results obtained.

  15. GADRAS Detector Response Function.

    SciTech Connect

    Mitchell, Dean J.; Harding, Lee; Thoreson, Gregory G; Horne, Steven M.

    2014-11-01

    The Gamma Detector Response and Analysis Software (GADRAS) applies a Detector Response Function (DRF) to compute the output of gamma-ray and neutron detectors when they are exposed to radiation sources. The DRF is fundamental to the ability to perform forward calculations (i.e., computation of the response of a detector to a known source), as well as the ability to analyze spectra to deduce the types and quantities of radioactive material to which the detectors are exposed. This document describes how gamma-ray spectra are computed and the significance of response function parameters that define characteristics of particular detectors.

  16. Test vehicle detector characterization system for the Boeing YAL-1 airborne laser

    E-print Network

    Steininger-Holmes, Jason Thomas

    2008-01-01

    The test vehicle detector characterization system provides a convenient and efficient tool for rapidly evaluating the optical sensitivity of the GAP6012, GAP100, GAP300, and GAP1000 indium gallium arsenide detectors used ...

  17. Improving the spectral resolution of a highly pixelated detector by applying a pixel-by-pixel energy calibration for investigating the spectral properties of the anode heel effect

    NASA Astrophysics Data System (ADS)

    Sievers, P.; Klammer, J.; Michel, T.; Hupe, O.; Anton, G.

    2012-07-01

    The energy deposition spectrum measured with highly pixelated photon-counting pixel detectors with a semiconductor sensor layer (e.g. silicon) differs significantly from the impinging X-ray spectrum. This is the main disadvantage compared to commonly known X-ray spectrometers, e.g. high purity Germanium (hpGe) detector. On the other hand, those hpGe-detectors have a lack of spatial resolution and can not be used for energy-resolved imaging. In case of measurements with highly pixelated detectors, a set of monoenergetic detector response functions is needed for the deconvolution of the measured distribution into the impinging spectrum. We have investigated the possibility of applying a pixel-by-pixel calibration on a highly pixelated detector for gaining a higher energy resolution and for lowering the minimal flux needed for the deconvolution. As a result it is now possible to utilize small ROIs of the pixel matrix for the deconvolution. With this analysis method the detector enables spectral X-ray imaging of high photon rates. This is in particular shown for the angular dependency of the anode heel effect on the emitted spectrum.

  18. Cosmic muon detector using proportional chambers

    NASA Astrophysics Data System (ADS)

    Varga, Dezs?; Gál, Zoltán; Hamar, Gerg?; Sára Molnár, Janka; Oláh, Éva; Pázmándi, Péter

    2015-11-01

    A set of classical multi-wire proportional chambers was designed and constructed with the main purpose of efficient cosmic muon detection. These detectors are relatively simple to construct, and at the same time are low cost, making them ideal for educational purposes. The detector layers have efficiencies above 99% for minimum ionizing cosmic muons, and their position resolution is about 1 cm, that is, particle trajectories are clearly observable. Visualization of straight tracks is possible using an LED array, with the discriminated and latched signal driving the display. Due to the exceptional operating stability of the chambers, the design can also be used for cosmic muon telescopes.

  19. Cosmic Muon Detector Using Proportional Chambers

    E-print Network

    Dezs? Varga; Zoltán Gál; Gerg? Hamar; Janka Sára Molnár; Éva Oláh; Péter Pázmándi

    2015-07-28

    A set of classical multi-wire proportional chambers were designed and constructed with the main purpose of efficient cosmic muon detection. These detectors are relatively simple to construct, and at the same time are low cost, making them ideal for educational purposes. The detector layers have efficiencies above 99% for minimum ionizing cosmic muons, and their position resolution is about 1 cm, that is, particle trajectories are clearly observable. Visualization of straight tracks is possible using an LED array, with the discriminated and latched signal driving the display. Due to the exceptional operating stability of the chambers, the design can also be used for cosmic muon telescopes.

  20. Trustworthiness of detectors in quantum key distribution with untrusted detectors

    NASA Astrophysics Data System (ADS)

    Qi, Bing

    2015-02-01

    Measurement-device-independent quantum key distribution (MDI-QKD) protocol has been demonstrated as a viable solution to detector side-channel attacks. Recently, to bridge the strong security of MDI-QKD with the high efficiency of conventional QKD, the detector-device-independent (DDI) QKD has been proposed. One crucial assumption made in DDI-QKD is that the untrusted Bell state measurement (BSM) located inside the receiver's laboratory cannot send any unwanted information to the outside. Here, we show that if the BSM is completely untrusted, a simple scheme would allow the BSM to send information to the outside. Combined with Trojan horse attacks, this scheme could allow an eavesdropper to gain information of the quantum key without being detected. To prevent the above attack, either countermeasures to Trojan horse attacks or some trustworthiness to the "untrusted" BSM device is required.

  1. Tin Can Radiation Detector.

    ERIC Educational Resources Information Center

    Crull, John L.

    1986-01-01

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

  2. Asynchronous Failure Detectors

    E-print Network

    Cornejo, Alejandro

    2013-10-10

    Failure detectors -- oracles that provide information about process crashes -- are an important abstraction for crash tolerance in distributed systems. The generality of failure-detector theory, while providing great ...

  3. LGB neutron detector

    NASA Astrophysics Data System (ADS)

    Quist, Nicole

    2012-10-01

    The double pulse signature of the Gadolinium Lithium Borate Cerium doped plastic detector suggests its effectiveness for analyzing neutrons while providing gamma ray insensitivity. To better understand this detector, a californium gamma/neutron time of flight facility was constructed in our lab. Reported here are efforts to understand the properties and applications of the LGB detector with regards to neutron spectroscopy.

  4. Tevatron detector upgrades

    SciTech Connect

    Lipton, R.; /Fermilab

    2005-01-01

    The D0 and CDF experiments are in the process of upgrading their detectors to cope with the high luminosities projected for the remainder of Tevatron Run II. They discuss the expected Tevatron environment through 2009, the detector challenges due to increasing luminosity in this period, and the solutions undertaken by the two experiments to mitigate detector problems and maximize physics results.

  5. Gamma ray detector shield

    DOEpatents

    Ohlinger, R.D.; Humphrey, H.W.

    1985-08-26

    A gamma ray detector shield comprised of a rigid, lead, cylindrical-shaped vessel having upper and lower portions with an pneumatically driven, sliding top assembly. Disposed inside the lead shield is a gamma ray scintillation crystal detector. Access to the gamma detector is through the sliding top assembly.

  6. Coated Fiber Neutron Detector Test

    SciTech Connect

    Lintereur, Azaree T.; Ely, James H.; Kouzes, Richard T.; Stromswold, David C.

    2009-10-23

    Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world, and thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Reported here are the results of tests of the 6Li/ZnS(Ag)-coated non-scintillating plastic fibers option. This testing measured the required performance for neutron detection efficiency and gamma ray rejection capabilities of a system manufactured by Innovative American Technology (IAT).

  7. The ATLAS Detector Control System

    NASA Astrophysics Data System (ADS)

    Lantzsch, K.; Arfaoui, S.; Franz, S.; Gutzwiller, O.; Schlenker, S.; Tsarouchas, C. A.; Mindur, B.; Hartert, J.; Zimmermann, S.; Talyshev, A.; Oliveira Damazio, D.; Poblaguev, A.; Braun, H.; Hirschbuehl, D.; Kersten, S.; Martin, T.; Thompson, P. D.; Caforio, D.; Sbarra, C.; Hoffmann, D.; Nemecek, S.; Robichaud-Veronneau, A.; Wynne, B.; Banas, E.; Hajduk, Z.; Olszowska, J.; Stanecka, E.; Bindi, M.; Polini, A.; Deliyergiyev, M.; Mandic, I.; Ertel, E.; Marques Vinagre, F.; Ribeiro, G.; Santos, H. F.; Barillari, T.; Habring, J.; Huber, J.; Arabidze, G.; Boterenbrood, H.; Hart, R.; Iakovidis, G.; Karakostas, K.; Leontsinis, S.; Mountricha, E.; Ntekas, K.; Filimonov, V.; Khomutnikov, V.; Kovalenko, S.; Grassi, V.; Mitrevski, J.; Phillips, P.; Chekulaev, S.; D'Auria, S.; Nagai, K.; Tartarelli, G. F.; Aielli, G.; Marchese, F.; Lafarguette, P.; Brenner, R.

    2012-12-01

    The ATLAS experiment is one of the multi-purpose experiments at the Large Hadron Collider (LHC) at CERN, constructed to study elementary particle interactions in collisions of high-energy proton beams. Twelve different sub detectors as well as the common experimental infrastructure are controlled and monitored by the Detector Control System (DCS) using a highly distributed system of 140 server machines running the industrial SCADA product PVSS. Higher level control system layers allow for automatic control procedures, efficient error recognition and handling, manage the communication with external systems such as the LHC controls, and provide a synchronization mechanism with the ATLAS data acquisition system. Different databases are used to store the online parameters of the experiment, replicate a subset used for physics reconstruction, and store the configuration parameters of the systems. This contribution describes the computing architecture and software tools to handle this complex and highly interconnected control system.

  8. Superconducting nano-strip particle detectors

    NASA Astrophysics Data System (ADS)

    Cristiano, R.; Ejrnaes, M.; Casaburi, A.; Zen, N.; Ohkubo, M.

    2015-12-01

    We review progress in the development and applications of superconducting nano-strip particle detectors. Particle detectors based on superconducting nano-strips stem from the parent devices developed for single photon detection (SSPD) and share with them ultra-fast response times (sub-nanosecond) and the ability to operate at a relatively high temperature (2–5 K) compared with other cryogenic detectors. SSPDs have been used in the detection of electrons, neutral and charged ions, and biological macromolecules; nevertheless, the development of superconducting nano-strip particle detectors has mainly been driven by their use in time-of-flight mass spectrometers (TOF-MSs) where the goal of 100% efficiency at large mass values can be achieved. Special emphasis will be given to this case, reporting on the great progress which has been achieved and which permits us to overcome the limitations of existing mass spectrometers represented by low detection efficiency at large masses and charge/mass ambiguity. Furthermore, such progress could represent a breakthrough in the field. In this review article we will introduce the device concept and detection principle, stressing the peculiarities of the nano-strip particle detector as well as its similarities with photon detectors. The development of parallel strip configuration is introduced and extensively discussed, since it has contributed to the significant progress of TOF-MS applications.

  9. Plastic neutron detectors.

    SciTech Connect

    Wilson, Tiffany M.S; King, Michael J.; Doty, F. Patrick

    2008-12-01

    This work demonstrated the feasibility and limitations of semiconducting {pi}-conjugated organic polymers for fast neutron detection via n-p elastic scattering. Charge collection in conjugated polymers in the family of substituted poly(p-phenylene vinylene)s (PPV) was evaluated using band-edge laser and proton beam ionization. These semiconducting materials can have high H/C ratio, wide bandgap, high resistivity and high dielectric strength, allowing high field operation with low leakage current and capacitance noise. The materials can also be solution cast, allowing possible low-cost radiation detector fabrication and scale-up. However, improvements in charge collection efficiency are necessary in order to achieve single particle detection with a reasonable sensitivity. The work examined processing variables, additives and environmental effects. Proton beam exposure was used to verify particle sensitivity and radiation hardness to a total exposure of approximately 1 MRAD. Conductivity exhibited sensitivity to temperature and humidity. The effects of molecular ordering were investigated in stretched films, and FTIR was used to quantify the order in films using the Hermans orientation function. The photoconductive response approximately doubled for stretch-aligned films with the stretch direction parallel to the electric field direction, when compared to as-cast films. The response was decreased when the stretch direction was orthogonal to the electric field. Stretch-aligned films also exhibited a significant sensitivity to the polarization of the laser excitation, whereas drop-cast films showed none, indicating improved mobility along the backbone, but poor {pi}-overlap in the orthogonal direction. Drop-cast composites of PPV with substituted fullerenes showed approximately a two order of magnitude increase in photoresponse, nearly independent of nanoparticle concentration. Interestingly, stretch-aligned composite films showed a substantial decrease in photoresponse with increasing stretch ratio. Other additives examined, including small molecules and cosolvents, did not cause any significant increase in photoresponse. Finally, we discovered an inverse-geometric particle track effect wherein increased track lengths created by tilting the detector off normal incidence resulted in decreased signal collection. This is interpreted as a trap-filling effect, leading to increased carrier mobility along the particle track direction. Estimated collection efficiency along the track direction was near 20 electrons/micron of track length, sufficient for particle counting in 50 micron thick films.

  10. Explosives (and other threats) detection using pulsed neutron interrogation and optimized detectors

    NASA Astrophysics Data System (ADS)

    Strellis, Dan A.; Elsalim, Mashal; Gozani, Tsahi

    2011-06-01

    We have previously reported results from a human-portable system using neutron interrogation to detect contraband and explosives. We summarized our methodology for distinguishing threat materials such as narcotics, C4, and mustard gas in the myriad of backgrounds present in the maritime environment. We are expanding our mission for the Domestic Nuclear Detection Office (DNDO) to detect Special Nuclear Material (SNM) through the detection of multiple fission signatures without compromising the conventional threat detection performance. This paper covers our initial investigations into using neutrons from compact pulsed neutron generators via the d(D,n)3He or d(T,n)? reactions with energies of ~2.5 and 14 MeV, respectively, for explosives (and other threats) detection along with a variety of gamma-ray detectors. Fast neutrons and thermal neutrons (after successive collisions) can stimulate the emission of various threat detection signatures. For explosives detection, element-specific gamma-ray signatures via the (n,n'?) inelastic scattering reaction and the (n,'?) thermal capture reaction are detected. For SNM, delayed gamma-rays following fission can be measured with the same detector. Our initial trade-off investigations of several gamma-ray detectors types (NaI, CsI, LaBr3, HPGe) for measuring gamma-ray signatures in a pulsed neutron environment for potential application in a human-portable active interrogation system are covered in this paper.

  11. Can scintillation detectors with low spectral resolution accurately determine radionuclides content of building materials?

    PubMed

    Kovler, K; Prilutskiy, Z; Antropov, S; Antropova, N; Bozhko, V; Alfassi, Z B; Lavi, N

    2013-07-01

    The current paper makes an attempt to check whether the scintillation NaI(Tl) detectors, in spite of their poor energy resolution, can determine accurately the content of NORM in building materials. The activity concentrations of natural radionuclides were measured using two types of detectors: (a) NaI(Tl) spectrometer equipped with the special software based on the matrix method of least squares, and (b) high-purity germanium spectrometer. Synthetic compositions with activity concentrations varying in a wide range, from 1/5 to 5 times median activity concentrations of the natural radionuclides available in the earth crust and the samples of popular building materials, such as concrete, pumice and gypsum, were tested, while the density of the tested samples changed in a wide range (from 860 up to 2,410 kg/m(3)). The results obtained in the NaI(Tl) system were similar to those obtained with the HPGe spectrometer, mostly within the uncertainty range. This comparison shows that scintillation spectrometers equipped with a special software aimed to compensate for the lower spectral resolution of NaI(Tl) detectors can be successfully used for the radiation control of mass construction products. PMID:23542118

  12. The vertex detector for the Lepton/Photon collaboration

    SciTech Connect

    Sullivan, J.P.; Boissevain, J.G.; Fox, D.; Hecke, H. van; Jacak, B.V.; Kapustinsky, J.S.; Leitch, M.J.; McGaughey, P.L.; Moss, J.M.; Sondheim, W.E.

    1991-12-31

    The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two con- centric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity ({nu}) distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed.

  13. Fabrication and Characterization of Superconducting NbN Nanowire Single Photon Detectors

    NASA Technical Reports Server (NTRS)

    Stern, Jeffrey A.; Farr, William H.

    2006-01-01

    We report on the fabrication and characterization of high-speed, single photon detectors using superconducting NbN nanowires at a wavelength of 1064 nm. A 15 by 15 micron detector with a detector efficiency of 40% has been measured. Due to kinetic inductance, the recovery time of such large area detectors is longer than that of smaller or single wire detectors. The recovery time of our detectors (50 ns) has been characterized by measuring the inter-arrival time statistics of our detector.

  14. High-energy detector

    DOEpatents

    Bolotnikov, Aleksey E. (South Setauket, NY); Camarda, Giuseppe (Farmingville, NY); Cui, Yonggang (Upton, NY); James, Ralph B. (Ridge, NY)

    2011-11-22

    The preferred embodiments are directed to a high-energy detector that is electrically shielded using an anode, a cathode, and a conducting shield to substantially reduce or eliminate electrically unshielded area. The anode and the cathode are disposed at opposite ends of the detector and the conducting shield substantially surrounds at least a portion of the longitudinal surface of the detector. The conducting shield extends longitudinally to the anode end of the detector and substantially surrounds at least a portion of the detector. Signals read from one or more of the anode, cathode, and conducting shield can be used to determine the number of electrons that are liberated as a result of high-energy particles impinge on the detector. A correction technique can be implemented to correct for liberated electron that become trapped to improve the energy resolution of the high-energy detectors disclosed herein.

  15. Monolithic short wave infrared (SWIR) detector array

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A monolithic self-scanned linear detector array was developed for remote sensing in the 1.1- 2.4-micron spectral region. A high-density IRCCD test chip was fabricated to verify new design approaches required for the detector array. The driving factors in the Schottky barrier IRCCD (Pdsub2Si) process development are the attainment of detector yield, uniformity, adequate quantum efficiency, and lowest possible dark current consistent with radiometric accuracy. A dual-band module was designed that consists of two linear detector arrays. The sensor architecture places the floating diffusion output structure in the middle of the chip, away from the butt edges. A focal plane package was conceptualized and includes a polycrystalline silicon substrate carrying a two-layer, thick-film interconnecting conductor pattern and five epoxy-mounted modules. A polycrystalline silicon cover encloses the modules and bond wires, and serves as a radiation and EMI shield, thermal conductor, and contamination seal.

  16. A multilayer surface detector for ultracold neutrons

    NASA Astrophysics Data System (ADS)

    Wang, Zhehui; Hoffbauer, M. A.; Morris, C. L.; Callahan, N. B.; Adamek, E. R.; Bacon, J. D.; Blatnik, M.; Brandt, A. E.; Broussard, L. J.; Clayton, S. M.; Cude-Woods, C.; Currie, S.; Dees, E. B.; Ding, X.; Gao, J.; Gray, F. E.; Hickerson, K. P.; Holley, A. T.; Ito, T. M.; Liu, C.-Y.; Makela, M.; Ramsey, J. C.; Pattie, R. W.; Salvat, D. J.; Saunders, A.; Schmidt, D. W.; Schulze, R. K.; Seestrom, S. J.; Sharapov, E. I.; Sprow, A.; Tang, Z.; Wei, W.; Wexler, J.; Womack, T. L.; Young, A. R.; Zeck, B. A.

    2015-10-01

    A multilayer surface detector for ultracold neutrons (UCNs) is described. The top 10B layer is exposed to vacuum and directly captures UCNs. The ZnS:Ag layer beneath the 10B layer is a few microns thick, which is sufficient to detect the charged particles from the 10B(n,?)7Li neutron-capture reaction, while thin enough that ample light due to ? and 7Li escapes for detection by photomultiplier tubes. A 100-nm thick 10B layer gives high UCN detection efficiency, as determined by the mean UCN kinetic energy, detector materials, and other parameters. Low background, including negligible sensitivity to ambient neutrons, has also been verified through pulse-shape analysis and comparison with other existing 3He and 10B detectors. This type of detector has been configured in different ways for UCN flux monitoring, development of UCN guides and neutron lifetime research.

  17. Suitability of detectors for imaging applications

    NASA Astrophysics Data System (ADS)

    Sanders, Jill M.; Spyrou, Nicholas M.

    Interest in computer assisted tomography has seen in recent years an increase in applications on a wider basis extending beyond medical investigations. Technological developments have made available a larger selection of detectors which may be employed in imaging studies. Limited resources in a university research group and the fact that some of the types of detectors are still at the research stage of production, e.g. cadmium telluride, demanded the investigation of parameters by which detectors may be selected for specific applications. Experiments using a scanning rig were carried out to measure efficiency, energy resolution, scatter, spatial resolution and detection limit for sodium iodide, bismuth germanate, caesium fluoride, cadmium telluride and intrinsic germanium detectors.

  18. Special Nuclear Material Detection with a Water Cherenkov based Detector

    SciTech Connect

    Sweany, M; Bernstein, A; Bowden, N; Dazeley, S; Svoboda, R

    2008-11-10

    Fission events from Special Nuclear Material (SNM), such as highly enriched uranium or plutonium, produce a number of neutrons and high energy gamma-rays. Assuming the neutron multiplicity is approximately Poissonian with an average of 2 to 3, the observation of time correlations between these particles from a cargo container would constitute a robust signature of the presence of SNM inside. However, in order to be sensitive to the multiplicity, one would require a high total efficiency. There are two approaches to maximize the total efficiency; maximizing the detector efficiency or maximizing the detector solid angle coverage. The advanced detector group at LLNL is investigating one way to maximize the detector size. We are designing and building a water Cerenkov based gamma and neutron detector for the purpose of developing an efficient and cost effective way to deploy a large solid angle car wash style detector. We report on our progress in constructing a larger detector and also present preliminary results from our prototype detector that indicates detection of neutrons.

  19. Detectors, sampling, shielding, and electronics for positron emission tomography

    SciTech Connect

    Derenzo, S.E.

    1981-08-01

    A brief discussion of the important design elements for positron emission tomographs is presented. The conclusions are that the instrumentation can be improved by the use of larger numbers of small, efficient detectors closely packed in many rings, the development of new detector materials, and novel electronic designs to reduce the deadtime and increase maximum event rates. (ACR)

  20. Design and Performance of Neutron Detector N*

    NASA Astrophysics Data System (ADS)

    Pawelczak, Iwona; Toke, Jan; Tsai, Yun-Tse; Udo Schröder, W.

    2008-04-01

    The design of the N* Detector (``Neutron Sandwich Transmuter/Activation-? Radiator'') and its response to neutrons are described. The N* is a high efficiency plastic-scintillation detector with sensitivity to neutrons in a wide energy range and multi-hit information. The device consists of a stack of plastic scintillator slabs (Saint Gobain BC-408) alternating with thin radiator films (PDMS), which are loaded with 0.5% (by weight) of Gd. The stack is coupled to a photomultiplier tube. The scintillator plays the dual role of a neutron moderator and a ?-radiation detector. Scintillation light is produced in response to both, the prompt moderation process and the delayed emission of Gd-capture ?-rays. The design and experimental results with respect to light response, energy and time resolution, and detection efficiency will be discussed, along with comparison to Monte Carlo simulations.

  1. Multi-layer boron thin-film detectors for neutrons

    SciTech Connect

    Wang, Zhehui; Morris, Christopher L

    2010-01-01

    Intrinsic efficiencies of the multilayer boron detectors have been examined both theoretically and experimentally. It is shown that due to the charge loss in the boron layers, the practical efficiencies of most multi-layer {sup 10}B detectors are limited up to about 42%, much less than 77% of the 2 bar 2-inch diameter {sup 3}He detectors. It is suggested that the same charge loss mechanism will prevent essentially all substrate-based boron detectors from ever reaching the efficiencies of high-pressure {sup 3}He tubes, independent of the substrate geometry and material composition (including silicon). Meanwhile, the experimental data indicate that the multi-layer approach can increase the efficiencies up to the theoretical limit. Good n/{gamma} discrimination has also achieved using the ionization charnber technique.

  2. Timing performance of superconducting nanowire single-photon detectors

    E-print Network

    Najafi, Faraz

    2015-01-01

    Superconducting nanowire single-photon detectors (SNSPDs) are becoming increasingly popular for applications in quantum information and long-distance communication. While the detection efficiency of SNSPDs has significantly ...

  3. SNM Detection with a Large Water Cerenkov Detector

    SciTech Connect

    Dazeley, S; Bernstein, A; Bowden, N; Ouedraogo, S; Svoboda, R; Sweeny, M

    2009-06-04

    Special Nuclear Material (SNM) can either spontaneously fission, or be induced to do so. Either case results in neutron emission. Since neutrons are highly penetrating and difficult to shield, they could, potentially, be detected escaping even a well shielded cargo container. Obviously, if the shielding is sophisticated, detecting it would require a highly efficient detector with close to 4{pi} solid angle coverage. Water Cerenkov detectors may be a cost effective way to achieve that goal if it can be shown that the neutron capture signature is large enough and if sufficient background rejection can be employed as detectors get larger. In 2008 the LLNL Advanced Detector Group reported the successful detection of neutrons with a 1/4 ton gadolinium doped water Cerenkov prototype. We have now built a 4 ton version. This detector is not only bigger, it was designed with photon detection efficiency in mind from the beginning. We are employing increased photocathode coverage and more reflective walls, coated with PTFE. The increased efficiency should allow better energy resolution. We expect that the better diffusive wall reflectivity will reduce the overall dependence of the detector response on particle direction, again producing a more consistent response. We also believe that as detectors get larger, both uncorrelated and correlated backgrounds due to gamma-rays and cosmic ray interactions near the detector will increase. To prove the effectiveness of the technology we must develop new ways to reject these backgrounds while maintaining our sensitivity to SNM neutrons. Better energy resolution will enable us to reject more of the low energy gamma-ray backgrounds on this basis. Overcoming cosmic ray induced neutrons is perhaps an even larger concern as detectors get larger. Our detector is designed so that we can test various segmentation schemes - effectively dividing the detector up into smaller ones. In this presentation, we will describe our detector in detail.

  4. The DŘ detector

    NASA Astrophysics Data System (ADS)

    Abachi, S.; Abolins, M.; Acharya, B. S.; Adam, I.; Ahn, S.; Aihara, H.; Alvarez, G.; Alves, G. A.; Amos, N.; Anderson, W.; Antipov, Yu.; Aronson, S. H.; Astur, R.; Avery, R. E.; Baden, A.; Balderston, J.; Baldin, B.; Bantly, J.; Barasch, E.; Bartlett, J. F.; Bazizi, K.; Behnke, T.; Bezzubov, V.; Bhat, P. C.; Blazey, G.; Blessing, S.; Boehnlein, A.; Borcherding, F.; Borders, J.; Bozko, N.; Brandt, A.; Brock, R.; Bross, A.; Buchholz, D.; Burtovoy, V.; Butler, J. M.; Callot, O.; Chakraborty, D.; Chekulaev, S.; Chen, J.; Chen, L.-P.; Chen, W.; Choudhary, B. C.; Christenson, J. H.; Claes, D.; Clark, A. R.; Cobau, W. G.; Cochran, J.; Cooper, W. E.; Cretsinger, C.; Cullen-Vidal, D.; Cummings, M.; Cutts, D.; Dahl, O. I.; Daniels, B.; De, K.; Demarteau, M.; Denisenko, K.; Denisenko, N.; Denisov, D.; Denisov, S.; Dharmaratna, W.; Diehl, H. T.; Diesburg, M.; Dixon, R.; Draper, P.; Ducros, Y.; Durston-Johnson, S.; Eartly, D.; Eberhard, P. H.; Edmunds, D.; Efimov, A.; Ellison, J.; Elvira, V. D.; Engelmann, R.; Eroshin, O.; Evdokimov, V.; Fahey, S.; Fanourakis, G.; Fatyga, M.; Featherly, J.; Feher, S.; Fein, D.; Ferbel, T.; Finley, D.; Finocchiaro, G.; Fisk, H. E.; Flattum, E.; Forden, G. E.; Fortner, M.; Franzini, P.; Fuess, S.; Gallas, E.; Gao, C. S.; Geld, T. L.; Genser, K.; Gerber, C. E.; Gibbard, B.; Glebov, V.; Glicenstein, J. F.; Gobbi, B.; Goforth, M.; Good, M. L.; Goozen, F.; Gordon, H.; Graf, N.; Grannis, P. D.; Green, D. R.; Green, J.; Greenlee, H.; Grossman, N.; Grudberg, P.; Guida, J. A.; Guida, J. M.; Guryn, W.; Hadley, N. J.; Haggerty, H.; Hagopian, S.; Hagopian, V.; Hall, R. E.; Hansen, S.; Hauptman, J.; Hedin, D.; Heinson, A. P.; Heintz, U.; Heuring, T.; Hirosky, R.; Hodel, K.; Hoftun, J. S.; Hubbard, J. R.; Huehn, T.; Huson, R.; Igarashi, S.; Ito, A. S.; James, E.; Jiang, J.; Johns, K.; Johnson, C. R.; Johnson, M.; Jonckheere, A.; Jones, M.; Jöstlein, H.; Jung, C. K.; Kahn, S.; Kanekal, S.; Kernan, A.; Kerth, L.; Kirunin, A.; Klatchko, A.; Klima, B.; Klochkov, B.; Klopfenstein, C.; Klyukhin, V.; Kochetkov, V.; Kohli, J. M.; Kononenko, W.; Kotcher, J.; Kotov, I.; Kourlas, J.; Kozelov, A.; Kozlovsky, E.; Krafczyk, G.; Krempetz, K.; Krishnaswamy, M. R.; Kroon, P.; Krzywdzinski, S.; Kunori, S.; Lami, S.; Landsberg, G.; Lanou, R. E.; Laurens, P.; Lee-Franzini, J.; Li, J.; Li, R.; Li-Demarteau, Q. Z.; Lima, J. G. R.; Linn, S. L.; Linnemann, J.; Lipton, R.; Liu, Y.-C.; Lloyd-Owen, D.; Lobkowicz, F.; Loken, S. C.; Lokos, S.; Lueking, L.; Maciel, A. K. A.; Madaras, R. J.; Madden, R.; Malamud, E.; Mangeot, Ph.; Manning, I.; Mansoulié, B.; Manzella, V.; Mao, H.-S.; Marcin, M.; Markosky, L.; Marshall, T.; Martin, H. J.; Martin, M. I.; Martin, P. S.; Marx, M.; May, B.; Mayorov, A.; McCarthy, R.; McKinley, J.; Mendoza, D.; Meng, X.-C.; Merritt, K. W.; Milder, A.; Mincer, A.; Mondal, N. K.; Montag, M.; Mooney, P.; Mudan, M.; Mulholland, G. T.; Murphy, C.; Murphy, C. T.; Nang, F.; Narain, M.; Narasimham, V. S.; Neal, H. A.; Nemethy, P.; Neši?, D.; Ng, K. K.; Norman, D.; Oesch, L.; Oguri, V.; Oltman, E.; Oshima, N.; Owen, D.; Pang, M.; Para, A.; Park, C. H.; Partridge, R.; Paterno, M.; Peryshkin, A.; Peters, M.; Pi, B.; Piekarz, H.; Pischalnikov, Yu.; Pizzuto, D.; Pluquet, A.; Podstavkov, V.; Pope, B. G.; Prosper, H. B.; Protopopescu, S.; Que, Y.-K.; Quintas, P. Z.; Rahal-Callot, G.; Raja, R.; Rajagopalan, S.; Rao, M. V. S.; Rasmussen, L.; Read, A. L.; Regan, T.; Repond, S.; Riadovikov, V.; Rijssenbeek, M.; Roe, N. A.; Rubinov, P.; Rutherfoord, J.; Santoro, A.; Sawyer, L.; Schamberger, R. D.; Sculli, J.; Selove, W.; Shea, M.; Shkurenkov, A.; Shupe, M.; Singh, J. B.; Sirotenko, V.; Smart, W.; Smith, A.; Smith, D.; Smith, R. P.; Snow, G. R.; Snyder, S.; Sosebee, M.; Souza, M.; Spadafora, A. L.; Stampke, S.; Stephens, R.; Stevenson, M. L.; Stewart, D.; Stocker, F.; Stoyanova, D.; Stredde, H.; Streets, K.; Strovink, M.; Suhanov, A.; Taketani, A.; Tartaglia, M.; Taylor, J. D.; Teiger, J.; Theodosiou, G.; Thompson, J.; Tisserant, S.; Trippe, T. G.; Tuts, P. M.; Van Berg, R.; Vaz, M.; Vishwanath, P. R.; Volkov, A.; Vorobiev, A.; Wahl, H. D.; Wang, D.-C.; Wang, L.-Z.; Weerts, H.; Wenzel, W. A.; White, A.; White, J. T.; Wightman, J.; Willis, S.; Wimpenny, S. J.; Wolf, Z.; Womersley, J.; Wood, D. R.; Xia, Y.; Xiao, D.; Xie, P.; Xu, H.; Yamada, R.; Yamin, P.; Yanagisawa, C.; Yang, J.; Yang, M.-J.; Yoshikawa, C.; Youssef, S.; Yu, J.; Zeller, R.; Zhang, S.; Zhou, Y. H.; Zhu, Q.; Zhu, Y.-S.; Zieminska, D.; Zieminski, A.; Zinchenko, A.; Zylberstejn, A.; DŘ Collaboration

    1994-01-01

    The DŘ detector is a large general purpose detector for the study of short-distance phenomena in high energy antiproton-proton collisions, now in operation at the Fermilab Tevatron collider. The detector focusses upon the detection of electrons, muons, jets and missing transverse momentum. We describe the design and performance of the major elements of the detector, including the tracking chambers, transition radiation detector, liquid argon calorimetry and muon detection. The associated electronics, triggering systems and data acquisition systems are presented. The global mechanical, high voltage, and experiment monitoring and control systems which support the detector are described. We also discuss the design and implementation of software and software support systems that are specific to DŘ.

  5. Lumped Element Kinetic Inductance Detectors

    NASA Astrophysics Data System (ADS)

    Doyle, S.; Mauskopf, P.; Naylon, J.; Porch, A.; Duncombe, C.

    2008-04-01

    Kinetic Inductance Detectors (KIDs) provide a promising solution to the problem of producing large format arrays of ultra sensitive detectors for astronomy. Traditionally KIDs have been constructed from superconducting quarter-wave resonant elements capacitively coupled to a co-planar feed line [1]. Photon detection is achieved by measuring the change in quasi-particle density caused by the splitting of Cooper pairs in the superconducting resonant element. This change in quasi-particle density alters the kinetic inductance, and hence the resonant frequency of the resonant element. This arrangement requires the quasi-particles generated by photon absorption to be concentrated at positions of high current density in the resonator. This is usually achieved through antenna coupling or quasi-particle trapping. For these detectors to work at wavelengths shorter than around 500 ?m where antenna coupling can introduce a significant loss of efficiency, then a direct absorption method needs to be considered. One solution to this problem is the Lumped Element KID (LEKID), which shows no current variation along its length and can be arranged into a photon absorbing area coupled to free space and therefore requiring no antennas or quasi-particle trapping. This paper outlines the relevant microwave theory of a LEKID, along with theoretical and measured performance for these devices.

  6. Radiation Effect On Gas Electron Multiplier Detector Performance

    SciTech Connect

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

    2011-06-01

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

  7. Radiation Effect On Gas Electron Multiplier Detector Performance

    NASA Astrophysics Data System (ADS)

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

    2011-06-01

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

  8. Background studies for NaI(Tl) detectors in the ANAIS dark matter project

    SciTech Connect

    Amaré, J.; Borjabad, S.; Cebrián, S.; Cuesta, C.; Fortuńo, D.; García, E.; Ginestra, C.; Gómez, H.; Martínez, M.; Oliván, M. A.; Ortigoza, Y.; Solórzano, A. Ortiz de; Pobes, C.; Puimedón, J.; Sarsa, M. L.; Villar, J. A.; Villar, P.

    2013-08-08

    Several large NaI(Tl) detectors, produced by different companies, have been operated in the Canfranc Underground Laboratory (LSC) in the frame of the ANAIS (Annual modulation with NaI Scintillators) project devoted to the direct detection of dark matter. A complete background model has been developed for a 9.6 kg detector (referred as ANAIS-0 prototype) after a long data taking at LSC. Activities from the natural chains of {sup 238}U and {sup 232}Th, and {sup 40}K in the NaI(Tl) crystal were evaluated applying different methods: discrimination of alpha particles vs beta/gamma background by Pulse Shape Analysis for quantifying the content of the natural chains and coincidence techniques for {sup 40}K. Radioactive contaminations in the detector and shielding components were also determined by HPGe spectrometry. Monte Carlo simulations using Geant4 package were carried out to evaluate their contribution. At high energies, most of the measured background is nicely reproduced; at low energy some non-explained components are still present, although some plausible background sources have been analyzed. The {sup 40}K content of the NaI(Tl) crystal has been confirmed to be the dominant contributor to the measured background with this detector. In addition, preliminary results of the background characterization, presently underway at the LSC, of two recently produced NaI(Tl) detectors, with 12.5 kg mass each, will be presented: cosmogenic induced activity has been clearly observed and is being quantified, and {sup 40}K activity at a level ten times lower than in ANAIS-0 has been determined.

  9. History of infrared detectors

    NASA Astrophysics Data System (ADS)

    Rogalski, A.

    2012-09-01

    This paper overviews the history of infrared detector materials starting with Herschel's experiment with thermometer on February 11th, 1800. Infrared detectors are in general used to detect, image, and measure patterns of the thermal heat radiation which all objects emit. At the beginning, their development was connected with thermal detectors, such as thermocouples and bolometers, which are still used today and which are generally sensitive to all infrared wavelengths and operate at room temperature. The second kind of detectors, called the photon detectors, was mainly developed during the 20th Century to improve sensitivity and response time. These detectors have been extensively developed since the 1940's. Lead sulphide (PbS) was the first practical IR detector with sensitivity to infrared wavelengths up to ˜3 ?m. After World War II infrared detector technology development was and continues to be primarily driven by military applications. Discovery of variable band gap HgCdTe ternary alloy by Lawson and co-workers in 1959 opened a new area in IR detector technology and has provided an unprecedented degree of freedom in infrared detector design. Many of these advances were transferred to IR astronomy from Departments of Defence research. Later on civilian applications of infrared technology are frequently called "dual-use technology applications." One should point out the growing utilisation of IR technologies in the civilian sphere based on the use of new materials and technologies, as well as the noticeable price decrease in these high cost technologies. In the last four decades different types of detectors are combined with electronic readouts to make detector focal plane arrays (FPAs). Development in FPA technology has revolutionized infrared imaging. Progress in integrated circuit design and fabrication techniques has resulted in continued rapid growth in the size and performance of these solid state arrays.

  10. Cherenkov water detector NEVOD

    NASA Astrophysics Data System (ADS)

    Petrukhin, A. A.

    2015-05-01

    A unique multipurpose Cherenkov water detector, the NEVOD facility, uses quasispherical measuring modules to explore all the basic components of cosmic rays on Earth's surface, including neutrinos. Currently, the experimental complex includes the Cherenkov water detector, a calibration telescope system, and a coordinate detector. This paper traces the basic development stages of NEVOD, examines research directions, presents the results obtained, including the search for the solution to the 'muon puzzle', and discusses possible future development prospects.

  11. Detectors (4/5)

    ScienceCinema

    None

    2011-10-06

    This lecture will serve as an introduction to particle detectors and detection techniques. In the first lecture, a historic overview of particle detector development will be given. In the second lecture, some basic techniques and concepts for particle detection will be discussed. In the third lecture, the interaction of particles with matter, the basis of particle detection, will be presented. The fourth and fifth lectures will discuss different detector types used for particle tracking, energy measurement and particle identification.

  12. Detectors (5/5)

    ScienceCinema

    None

    2011-10-06

    This lecture will serve as an introduction to particle detectors and detection techniques. In the first lecture, a historic overview of particle detector development will be given. In the second lecture, some basic techniques and concepts for particle detection will be discussed. In the third lecture, the interaction of particles with matter, the basis of particle detection, will be presented. The fourth and fifth lectures will discuss different detector types used for particle tracking, energy measurement and particle identification.

  13. Status of the D0 fiber tracker and preshower detectors

    SciTech Connect

    Smirnov, Dmitri; ,

    2009-01-01

    In this report we focus on the performance of the D0 central fiber tracker and preshower detectors during the high luminosity p{bar p} collisions at {radical}s = 1.96 GeV delivered by the Tevatron collider at Fermilab (Run IIb). Both fiber tracker and preshower detectors utilize a similar readout system based on high quantum efficiency solid state photo-detectors capable of converting light into electrical signals. We also give a brief description of the D0 detector and the central track trigger, and conclude with a summary on the central tracker performance.

  14. Scintillation detectors in gamma spectral logging; geometry, absorption and calibration

    USGS Publications Warehouse

    Schimschal, Ulrich

    1980-01-01

    The theory for the evaluation of the effects of geometry in gamma ray absorption is developed for cylindrical scintillation detectors as applicable to borehole gamma spectrometry. The results of a laboratory experiment are shown for comparison. A calibration procedure to determine detector efficiency is given for application to borehole probes. It is shown that the response of a crystal can be separated in terms of geometric effects and instrumentation effects. It is also shown that approximating crystal detectors with point detectors in mathematical theory is grossly oversimplified. (USGS)

  15. Plasmonic lens enhanced mid-infrared quantum cascade detector

    NASA Astrophysics Data System (ADS)

    Harrer, Andreas; Schwarz, Benedikt; Gansch, Roman; Reininger, Peter; Detz, Hermann; Zederbauer, Tobias; Andrews, Aaron Maxwell; Schrenk, Werner; Strasser, Gottfried

    2014-10-01

    We demonstrate monolithic integrated quantum cascade detectors enhanced by plasmonic lenses. Surface normal incident mid-infrared radiation is coupled to surface plasmon polaritons guided to and detected by the active region of the detector. The lens extends the optical effective active area of the device up to a 5 times larger area than for standard mesa detectors or pixel devices while the electrical active region stays the same. The extended optical area increases the absorption efficiency of the presented device as well as the room temperature performance while it offers a flexible platform for various detector geometries. A photocurrent response increase at room temperature up to a factor of 6 was observed.

  16. Plasmonic lens enhanced mid-infrared quantum cascade detector

    SciTech Connect

    Harrer, Andreas Schwarz, Benedikt; Gansch, Roman; Reininger, Peter; Detz, Hermann; Zederbauer, Tobias; Andrews, Aaron Maxwell; Schrenk, Werner; Strasser, Gottfried

    2014-10-27

    We demonstrate monolithic integrated quantum cascade detectors enhanced by plasmonic lenses. Surface normal incident mid-infrared radiation is coupled to surface plasmon polaritons guided to and detected by the active region of the detector. The lens extends the optical effective active area of the device up to a 5 times larger area than for standard mesa detectors or pixel devices while the electrical active region stays the same. The extended optical area increases the absorption efficiency of the presented device as well as the room temperature performance while it offers a flexible platform for various detector geometries. A photocurrent response increase at room temperature up to a factor of 6 was observed.

  17. The ATLAS Inner Detector operation, data quality and tracking performance

    E-print Network

    Ewa Stanecka; on behalf of the ATLAS Collaboration

    2013-03-14

    The ATLAS Inner Detector is responsible for particle tracking in ATLAS experiment at CERN Large Hadron Collider (LHC) and comprises silicon and gas based detectors. The combination of both silicon and gas based detectors provides high precision impact parameter and momentum measurement of charged particles, with high efficiency and small fake rate. The ID has been used to exploit fully the physics potential of the LHC since the first proton-proton collisions at 7 TeV were delivered in 2009. The performance of track and vertex reconstruction is presented, as well as the operation aspects of the Inner Detector and the data quality during the many months of data taking.

  18. Operational experience with the CDF Run II Silicon Detector

    SciTech Connect

    Mondragon, Miguel N.; /Fermilab

    2010-01-01

    The CDF Run II Silicon Detector is the largest operating silicon detector in High Energy Physics. Its 722,000 channels spread over 7 m{sup 2} of silicon micro-strip sensors allow precision tracking and vertexing. The CDF silicon detector played a critical role in the discovery of B{sub s} mixing and is used extensively for the current Higgs Boson searches. Over the last 7 years, the detector efficiency has remained stable at 95% after the Run II commissioning period. The infrastructure (cooling, power supplies) problems dealt with are discussed.

  19. ALFA Detector Control System

    E-print Network

    Oleiro Seabra, Luis Filipe; The ATLAS collaboration

    2015-01-01

    ALFA (Absolute Luminosity For ATLAS) is one of the sub-detectors of ATLAS/LHC. The ALFA system is composed by two stations installed in the LHC tunnel 240 m away from each side of the ATLAS interaction point. Each station has a vacuum and ventilation system, movement control and all the required electronic for signal processing. The Detector Control System (DCS) provides control and monitoring of several components and ensures the safe operation of the detector contributing to good Data Quality. This paper describes the ALFA DCS system including a detector overview, operation aspects and hardware control through a SCADA system, WinCC OA.

  20. ALFA Detector Control System

    E-print Network

    Oleiro Seabra, Luis Filipe; The ATLAS collaboration

    2015-01-01

    ALFA (Absolute Luminosity For ATLAS) is one of the sub-detectors of ATLAS (A Toroidal LHC Apparatus). The ALFA system is composed by four stations installed in the LHC tunnel 240 m away from the ATLAS interaction point. Each station has a vacuum and ventilation system, movement control and all the required electronics for signal processing. The Detector Control System (DCS) provides control and monitoring of several components and ensures the safe operation of the detector contributing to good Data Quality. This paper describes the ALFA DCS system including a detector overview, operation aspects and hardware control through a SCADA system, WinCC OA.

  1. Adaptors for radiation detectors

    SciTech Connect

    Livesay, Ronald Jason

    2014-04-22

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

  2. Adaptors for radiation detectors

    DOEpatents

    Livesay, Ronald Jason

    2015-07-28

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

  3. The CDFII Silicon Detector

    SciTech Connect

    Julia Thom

    2004-07-23

    The CDFII silicon detector consists of 8 layers of double-sided silicon micro-strip sensors totaling 722,432 readout channels, making it one of the largest silicon detectors in present use by an HEP experiment. After two years of data taking, we report on our experience operating the complex device. The performance of the CDFII silicon detector is presented and its impact on physics analyses is discussed. We have already observed measurable effects from radiation damage. These results and their impact on the expected lifetime of the detector are briefly reviewed.

  4. Neutron beam imaging with GEM detectors

    NASA Astrophysics Data System (ADS)

    Albani, G.; Croci, G.; Cazzaniga, C.; Cavenago, M.; Claps, G.; Muraro, A.; Murtas, F.; Pasqualotto, R.; Perelli Cippo, E.; Rebai, M.; Tardocchi, M.; Gorini, G.

    2015-04-01

    Neutron GEM-based detectors represent a new frontier of devices in neutron physics applications where a very high neutron flux must be measured such as future fusion experiments (e.g. ITER Neutral beam Injector) and spallation sources (e.g. the European Spallation source). This kind of detectors can be properly adapted to be used both as beam monitors but also as neutron diffraction detectors that could represent a valid alternative for the 3He detectors replacement. Fast neutron GEM detectors (nGEM) feature a cathode composed by one layer of polyethylene and one of aluminium (neutron scattering on hydrogen generates protons that are detected in the gas) while thermal neutron GEM detectors (bGEM) are equipped with a borated aluminium cathode (charged particles are generated through the 10B(n,?)7Li reaction). GEM detectors can be realized in large area (1 m2) and their readout can be pixelated. Three different prototypes of nGEM and one prototype of bGEM detectors of different areas and equipped with different types of readout have been built and tested. All the detectors have been used to measure the fast and thermal neutron 2D beam image at the ISIS-VESUVIO beamline. The different kinds of readout patterns (different areas of the pixels) have been compared in similar conditions. All the detectors measured a width of the beam profile consitent with the expected one. The imaging property of each detector was then tested by inserting samples of different material and shape in the beam. All the samples were correctly reconstructed and the definition of the reconstruction depends on the type of readout anode. The fast neutron beam profile reconstruction was then compared to the one obtained by diamond detectors positioned on the same beamline while the thermal neutron one was compared to the imaged obtained by cadmium-coupled x-rays films. Also efficiency and the gamma background rejection have been determined. These prototypes represent the first step towards the realization of new neutron beam monitors for fusion experiments and spallation sources.

  5. Enabling photon counting detectors with dynamic attenuators

    NASA Astrophysics Data System (ADS)

    Hsieh, Scott S.; Pelc, Norbert J.

    2014-03-01

    Photon-counting x-ray detectors (PCXDs) are being investigated as a replacement for conventional x-ray detectors because they promise several advantages, including better dose efficiency, higher resolution and spectral imaging. However, many of these advantages disappear when the x-ray flux incident on the detector is too high. We recently proposed a dynamic, piecewise-linear attenuator (or beam shaping filter) that can control the flux incident on the detector. This can restrict the operating range of the PCXD to keep the incident count rate below a given limit. We simulated a system with the piecewise-linear attenuator and a PCXD using raw data generated from forward projected DICOM files. We investigated the classic paralyzable and nonparalyzable PCXD as well as a weighted average of the two, with the weights chosen to mimic an existing PCXD (Taguchi et al, Med Phys 2011). The dynamic attenuator has small synergistic benefits with the nonparalyzable detector and large synergistic benefits with the paralyzable detector. Real PCXDs operate somewhere between these models, and the weighted average model still shows large benefits from the dynamic attenuator. We conclude that dynamic attenuators can reduce the count rate performance necessary for adopting PCXDs.

  6. Tracking Performance of the ATLAS Inner Detector

    NASA Astrophysics Data System (ADS)

    Lauren, Tompkins; Heinemann, Beate

    2009-05-01

    The ATLAS experiment is one of the large scale experiments designed to explore high energy collisions at the Large Hadron Collider, a proton-proton accelerator with a center of mass energy of 14 TeV. Tracking of the individual particle trajectories in the ATLAS experiment is provided by the Inner Detector. It consists of three layers of silicon pixel detectors, four layers of silicon strip detectors, and a transition radiation tracker comprised of straw proportional tubes, which provides both tracking and transition radiation detection. In preparation for collision data the ATLAS experiment has taken large amounts of cosmic ray data that have been used to calibrate and align the tracking detectors. In this presentation we will show the observed tracking performance of the Inner Detector in cosmic ray data and compare it to the expected performance for collisions using simulated data. We will examine resolutions, efficiencies and mis-identification rates to paint a picture of the tracking performance in both early data and at the detector's design luminosity.

  7. 6Li foil thermal neutron detector

    SciTech Connect

    Ianakiev, Kiril D; Swinhoe, Martyn T; Favalli, Andrea; Chung, Kiwhan; Macarthur, Duncan W

    2010-01-01

    In this paper we report on the design of a multilayer thermal neutron detector based on {sup 6}Li reactive foil and thin film plastic scintillators. The {sup 6}Li foils have about twice the intrinsic efficiency of {sup 10}B films and about four times higher light output due to a unique combination of high energy of reaction particles, low self absorption, and low ionization density of tritons. The design configuration provides for double sided readout of the lithium foil resulting in a doubling of the efficiency relative to a classical reactive film detector and generating a pulse height distribution with a valley between neutron and gamma signals similar to {sup 3}He tubes. The tens of microns thickness of plastic scintillator limits the energy deposited by gamma rays, which provides the necessary neutron/gamma discrimination. We used MCNPX to model a multilayer Li foil detector design and compared it with the standard HLNCC-II (18 {sup 3}He tubes operated at 4 atm). The preliminary results of the {sup 6}Li configuration show higher efficiency and one third of the die-away time. These properties, combined with the very short dead time of the plastic scintillator, offer the potential of a very high performance detector.

  8. Measurement of terrestrial gamma radiation dose-rate (TGRD) level in soil samples from the district of Rembau, Malaysia, using high-purity Germanium detectors

    NASA Astrophysics Data System (ADS)

    Norbani, N. E.; Abdullah Salim, N. A.; Rahman, A. T. Abdul

    2014-11-01

    This study assesses the gamma radiation levels and associated dose rates from the naturally occurring radionuclides 232Th, 238U and 40K in soil samples collected from the district of Rembau, Malaysia using High-purity Germanium (HPGe) Detectors. A 105 measurement were performed on surface soil using NaI (Tl) gamma-ray detector with crystal size 1"x1", covering about 83% land of the Rembau district. The concentration of the naturally occurring radionuclides 232Th, 238U and 40K in soil samples collected were determined by using HPGe detector based on high-resolution gamma spectrometry system at Malaysia Nuclear Agency. The range of natural gamma radiation measured was from 114ą14 nGy h-1 to 857ą14 nGy h-1. The range of activity concentrations of U, Th and °K in soil from the studied areas varies from 151-401 Bq kg-1, 113-342 Bq kg-1 and 674-1526 Bq kg-1 with mean values of 245 Bq kg-1, 186 Bq kg-1 and 1152 Bq kg1 respectively. The mean values of terrestrial gamma radiation dose rate measured in Rembau district is 383ą18 nGy h-1 compared to the Malaysian average is 92 nGy h-1 and world average is 59 nGy h-1 (UNSCEAR, 2000). The average annual dose from such terrestrial gamma radiation dose rates to an individual in Rembau district, assuming a tropical rural setting is estimated to be 0.78 mSv per year, which is considered to be within the normal range for doses from natural sources. An isodose map for the Rembau district has been plotted.

  9. Advances in Detector Technology for Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    McCreight, Craig; Cheng, P. L. (Technical Monitor)

    1995-01-01

    Progress in semiconductor materials and processing technology has allowed the development of infrared detector arrays with unprecedented sensitivity, for imaging and spectroscopic applications in astronomy. The earlier discrete-detector approach has been replaced by large-element (up to 1024 x 1024 pixel), multiplexed devices. Progress has been made against a number of key limiting factors, such as quantum efficiency, noise, spectral response, linearity, and dark current. Future developments will focus on the need for even larger arrays, which operate at higher temperatures.

  10. SOLAR SYSTEM OBJECTS AS COSMIC RAYS DETECTORS

    SciTech Connect

    Privitera, P.; Motloch, P.

    2014-08-10

    In a recent Letter, Jupiter is presented as an efficient detector for Ultra-High Energy Cosmic Rays (UHECRs), through measurement by an Earth-orbiting satellite of gamma rays from UHECRs showers produced in Jupiter's atmosphere. We show that this result is incorrect, due to erroneous assumptions on the angular distribution of shower particles. We evaluated other solar system objects as potential targets for UHECRs detection, and found that the proposed technique is either not viable or not competitive with traditional ground-based UHECRs detectors.

  11. Self consistent, absolute calibration technique for photon number resolving detectors

    E-print Network

    Avella, A; Degiovanni, I P; Genovese, M; Gramegna, M; Lolli, L; Monticone, E; Portesi, C; Rajteri, M; Rastello, M L; Taralli, E; Traina, P; White, M; 10.1364/OE.19.023249

    2011-01-01

    Well characterized photon number resolving detectors are a requirement for many applications ranging from quantum information and quantum metrology to the foundations of quantum mechanics. This prompts the necessity for reliable calibration techniques at the single photon level. In this paper we propose an innovative absolute calibration technique for photon number resolving detectors, using a pulsed heralded photon source based on parametric down conversion. The technique, being absolute, does not require reference standards and is independent upon the performances of the heralding detector. The method provides the results of quantum efficiency for the heralded detector as a function of detected photon numbers. Furthermore, we prove its validity by performing the calibration of a Transition Edge Sensor based detector, a real photon number resolving detector that has recently demonstrated its effectiveness in various quantum information protocols.

  12. Self consistent, absolute calibration technique for photon number resolving detectors

    E-print Network

    A. Avella; G. Brida; I. P. Degiovanni; M. Genovese; M. Gramegna; L. Lolli; E. Monticone; C. Portesi; M. Rajteri; M. L. Rastello; E. Taralli; P. Traina; M. White

    2011-11-16

    Well characterized photon number resolving detectors are a requirement for many applications ranging from quantum information and quantum metrology to the foundations of quantum mechanics. This prompts the necessity for reliable calibration techniques at the single photon level. In this paper we propose an innovative absolute calibration technique for photon number resolving detectors, using a pulsed heralded photon source based on parametric down conversion. The technique, being absolute, does not require reference standards and is independent upon the performances of the heralding detector. The method provides the results of quantum efficiency for the heralded detector as a function of detected photon numbers. Furthermore, we prove its validity by performing the calibration of a Transition Edge Sensor based detector, a real photon number resolving detector that has recently demonstrated its effectiveness in various quantum information protocols.

  13. Proton Recoil Detectors and Fission Ionization Chambers for Neutron Dosimetry

    NASA Astrophysics Data System (ADS)

    Wilson, Brent; McMahan, Peggy; Barquest, Brad; Johnson, Mike

    2006-10-01

    This research involved the creation and development of detectors for the measurement of neutron flux. These detectors will be utilized to obtain dose information for fast neutron irradiations of electronic components, materials, and biological samples in the new neutron beamline at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. As a first step, we have developed two well-established neutron detectors -- the proton recoil detector and the fission ionization chamber -- for the energy range of the neutrons at our facility, 5 to 30 MeV. Using activation foil measurements (to obtain absolute neutron flux) and time-of-flight measurements with a Stilbene detector (to obtain the neutron energy spectra), we can calculate the efficiency of our detectors for both monoenergetic and white spectrum neutrons in this energy range.

  14. Alkali ionization detector

    DOEpatents

    Hrizo, John (Monroeville, PA); Bauerle, James E. (Plum Borough, PA); Witkowski, Robert E. (West Mifflin, PA)

    1982-01-01

    A calibration filament containing a sodium-bearing compound is included in combination with the sensing filament and ion collector plate of a sodium ionization detector to permit periodic generation of sodium atoms for the in-situ calibration of the detector.

  15. The TESLA Detector

    E-print Network

    Klaus Moenig

    2001-11-05

    For the superconducting linear collider TESLA a multi purpose detector has been designed. This detector is optimised for the important physics processes expected at a next generation linear collider up to around 1 TeV and is designed for the specific environment of a superconducting collider.

  16. Particle impact location detector

    NASA Technical Reports Server (NTRS)

    Auer, S. O.

    1974-01-01

    Detector includes delay lines connected to each detector surface strip. When several particles strike different strips simultaneously, pulses generated by each strip are time delayed by certain intervals. Delay time for each strip is known. By observing time delay in pulse, it is possible to locate strip that is struck by particle.

  17. Cable-splice detector

    NASA Technical Reports Server (NTRS)

    Lee, R. D.; Iufer, E. J.; Giovannetti, A.

    1980-01-01

    Detector has possible uses in aerial cable-car systems, equipment handling in mines, boreholes, and undersea operations, and other applications where moving steel cable must be measured, monitored, or controlled. Detector consists of Hall-effect magnetic sensor located close to cable. Magnetic markings on cable are converted to electrical signals. Signals are filtered, amplified, and can actuate alarm.

  18. The CLAS Cherenkov detector

    SciTech Connect

    G. Adams; V. Burkert; R. Carl; T. Carstens; V. Frolov; L. Houghtlin; G. Jacobs; M. Kossov; M. Klusman; B. Kross; M. Onuk; J. Napolitano; J. W. Price; C. Riggs; Y. Sharabian; A. Stavinsky; L. C. Smith; W. A. Stephens; P. Stoler; W. Tuzel; K. Ullrich; A. Vlassovc; A. Weisenberger; M. Witkowski; B. Wojtekhowski; P. F. Yergin; C. Zorn

    2001-06-01

    The design, construction, and performance of the CLAS Cerenkov threshold gas detector at Jefferson Lab is described. The detector consists of 216 optical modules. Each module consists of 3 adjustable mirrors, of lightweight composite construction, a Winston light collecting cone, a 5-inch photomultiplier tube, and specially designed magnetic shielding.

  19. Arsenic activation neutron detector

    DOEpatents

    Jacobs, Eddy L. (Albuquerque, NM)

    1981-01-01

    A detector of bursts of neutrons from a deuterium-deuteron reaction includes a quantity of arsenic adjacent a gamma detector such as a scintillator and photomultiplier tube. The arsenic is activated by the 2.5 Mev neutrons to release gamma radiation which is detected to give a quantitative representation of detected neutrons.

  20. Arsenic activation neutron detector

    DOEpatents

    Jacobs, E.L.

    1980-01-28

    A detector of bursts of neutrons from a deuterium-deuteron reaction includes a quantity of arsenic adjacent a gamma detector such as a scintillator and photomultiplier tube. The arsenic is activated by the 2.5-MeV neutrons to release gamma radiation which is detected to give a quantitative representation of detected neutrons.

  1. Smoke Detectors and Legislation.

    ERIC Educational Resources Information Center

    National Fire Prevention and Control Administration (DOC), Washington, DC.

    This manual, one of a series for use in public education, provides an in-depth review of the current status of state and local smoke detector legislation. First, for the community considering a smoke detector law or ordinance, six decision points are discussed: which residential occupancy sub-classes will be affected; what the time factors are for…

  2. Graphene vertical hot-electron terahertz detectors

    SciTech Connect

    Ryzhii, V.; Satou, A.; Otsuji, T.; Ryzhii, M.; Mitin, V.; Shur, M. S.

    2014-09-21

    We propose and analyze the concept of the vertical hot-electron terahertz (THz) graphene-layer detectors (GLDs) based on the double-GL and multiple-GL structures with the barrier layers made of materials with a moderate conduction band off-set (such as tungsten disulfide and related materials). The operation of these detectors is enabled by the thermionic emissions from the GLs enhanced by the electrons heated by incoming THz radiation. Hence, these detectors are the hot-electron bolometric detectors. The electron heating is primarily associated with the intraband absorption (the Drude absorption). In the frame of the developed model, we calculate the responsivity and detectivity as functions of the photon energy, GL doping, and the applied voltage for the GLDs with different number of GLs. The detectors based on the cascade multiple-GL structures can exhibit a substantial photoelectric gain resulting in the elevated responsivity and detectivity. The advantages of the THz detectors under consideration are associated with their high sensitivity to the normal incident radiation and efficient operation at room temperature at the low end of the THz frequency range. Such GLDs with a metal grating, supporting the excitation of plasma oscillations in the GL-structures by the incident THz radiation, can exhibit a strong resonant response at the frequencies of several THz (in the range, where the operation of the conventional detectors based on A{sub 3}B{sub 5} materials, in particular, THz quantum-well detectors, is hindered due to a strong optical phonon radiation absorption in such materials). We also evaluate the characteristics of GLDs in the mid- and far-infrared ranges where the electron heating is due to the interband absorption in GLs.

  3. Pyroelectric detector arrays

    NASA Technical Reports Server (NTRS)

    Fripp, A. L.; Robertson, J. B.; Breckenridge, R. A. (inventors)

    1982-01-01

    A pryoelectric detector array and the method for making it are described. A series of holes formed through a silicon dioxide layer on the surface of a silicon substrate forms the mounting fixture for the pyroelectric detector array. A series of nontouching strips of indium are formed around the holes to make contact with the backside electrodes and form the output terminals for individual detectors. A pyroelectric detector strip with front and back electrodes, respectively, is mounted over the strip. Biasing resistors are formed on the surface of the silicon dioxide layer and connected to the strips. A metallized pad formed on the surface of the layer is connected to each of the biasing resistors and to the film to provide the ground for the pyroelectric detector array.

  4. Pyroelectric detector arrays

    NASA Technical Reports Server (NTRS)

    Fripp, A. L.; Robertson, J. B.; Breckenridge, R. (inventors)

    1982-01-01

    A pyroelectric detector array and the method for using it are described. A series of holes formed through a silicon dioxide layer on the surface of a silicon substrate forms the mounting fixture for the pyroelectric detector array. A series of nontouching strips of indium are formed around the holes to make contact with the backside electrodes and form the output terminals for individual detectors. A pyroelectric detector strip with front and back electrodes, respectively, is mounted over the strips. Biasing resistors are formed on the surface of the silicon dioxide layer and connected to the strips. A metallized pad formed on the surface of layer is connected to each of the biasing resistors and to the film to provide the ground for the pyroelectric detector array.

  5. Optimal optoacoustic detector design

    NASA Technical Reports Server (NTRS)

    Rosengren, L.-G.

    1975-01-01

    Optoacoustic detectors are used to measure pressure changes occurring in enclosed gases, liquids, or solids being excited by intensity or frequency modulated electromagnetic radiation. Radiation absorption spectra, collisional relaxation rates, substance compositions, and reactions can be determined from the time behavior of these pressure changes. Very successful measurements of gaseous air pollutants have, for instance, been performed by using detectors of this type together with different lasers. The measuring instrument consisting of radiation source, modulator, optoacoustic detector, etc. is often called spectrophone. In the present paper, a thorough optoacoustic detector optimization analysis based upon a review of its theory of operation is introduced. New quantitative rules and suggestions explaining how to design detectors with maximal pressure responsivity and over-all sensitivity and minimal background signal are presented.

  6. Advanced far infrared detectors

    SciTech Connect

    Haller, E.E.

    1993-05-01

    Recent advances in photoconductive and bolometric semiconductor detectors for wavelength 1 mm > {lambda} > 50 {mu}m are reviewed. Progress in detector performance in this photon energy range has been stimulated by new and stringent requirements for ground based, high altitude and space-borne telescopes for astronomical and astrophysical observations. The paper consists of chapters dealing with the various types of detectors: Be and Ga doped Ge photoconductors, stressed Ge:Ga devices and neutron transmutation doped Ge thermistors. Advances in the understanding of basic detector physics and the introduction of modern semiconductor device technology have led to predictable and reliable fabrication techniques. Integration of detectors into functional arrays has become feasible and is vigorously pursued by groups worldwide.

  7. Nanomechanical resonance detector

    DOEpatents

    Grossman, Jeffrey C; Zettl, Alexander K

    2013-10-29

    An embodiment of a nanomechanical frequency detector includes a support structure and a plurality of elongated nanostructures coupled to the support structure. Each of the elongated nanostructures has a particular resonant frequency. The plurality of elongated nanostructures has a range of resonant frequencies. An embodiment of a method of identifying an object includes introducing the object to the nanomechanical resonance detector. A resonant response by at least one of the elongated nanostructures of the nanomechanical resonance detector indicates a vibrational mode of the object. An embodiment of a method of identifying a molecular species of the present invention includes introducing the molecular species to the nanomechanical resonance detector. A resonant response by at least one of the elongated nanostructures of the nanomechanical resonance detector indicates a vibrational mode of the molecular species.

  8. Arc detector uses fiber optics

    NASA Technical Reports Server (NTRS)

    Finnegan, E. J.; Leech, R. A.

    1979-01-01

    Arc detector for protecting high-power microwave klystron oscillators uses fiber optics connected to remote solid-state light-sensing circuits. Detector is more reliable, smaller, and sensitive than other systems that locate detector in waveguide.

  9. Recent developments in GEM-based neutron detectors

    NASA Astrophysics Data System (ADS)

    Saenboonruang, K.

    2015-05-01

    The gas electron multiplier (GEM) detector is a relatively new gaseous detector that has been utilized for less than 20 years. Since the discovery in 1997 by F. Sauli, the GEM detector has shown excellent properties including high rate capability, excellent resolution, low discharge probability, and excellent radiation hardness. These promising properties have led the GEM detector to gain popularity and attention amongst physicists and researchers. In particular, the GEM detector can also be modified to be used as a neutron detector by adding appropriate neutron converters. With properties stated above and the need to replace the previous expensive 3He-based neutron detectors, the GEM-based neutron detector could be one of the most powerful and affordable neutron detectors. Applications of the GEM-based neutron detectors vary from researches in nuclear and particle physics, neutron imaging, and national security. Although several promising progresses and results have been shown and published in the past few years, further improvement is still needed in order to improve the low neutron detection efficiency (only a few percent) and to widen the possibilities for other uses.

  10. Fabrication and Characterization of Superconducting NbN Nanowire Single Photon Detectors

    NASA Technical Reports Server (NTRS)

    Stern, Jeffrey A.; Farr, William H.

    2006-01-01

    This viewgraph presentation describes the fabrication of large area superconducting Niobium Nitride nanowire single photon detectors. The topics include: 1) Introduction and Motivation; 2) Operation of SNSPD Detectors; 3) NbTiN Deposition; 4) Fabrication Details; 5) Backside Coupled SNSPD; 6) Measurement Apparatus; 7) Electrical Response of a 15x15 micrometer SNSPD to 1064nm radiation; 8) Detector Efficiency vs Bias Current; 9) Interarrival Time Plot; 10) Detector Linearity; and 11) Conclusion.

  11. Detectors for Tomorrow's Instruments

    NASA Technical Reports Server (NTRS)

    Moseley, Harvey

    2009-01-01

    Cryogenically cooled superconducting detectors have become essential tools for a wide range of measurement applications, ranging from quantum limited heterodyne detection in the millimeter range to direct searches for dark matter with superconducting phonon detectors operating at 20 mK. Superconducting detectors have several fundamental and practical advantages which have resulted in their rapid adoption by experimenters. Their excellent performance arises in part from reductions in noise resulting from their low operating temperatures, but unique superconducting properties provide a wide range of mechanisms for detection. For example, the steep dependence of resistance with temperature on the superconductor/normal transition provides a sensitive thermometer for calorimetric and bolometric applications. Parametric changes in the properties of superconducting resonators provides a mechanism for high sensitivity detection of submillimeter photons. From a practical point of view, the use of superconducting detectors has grown rapidly because many of these devices couple well to SQUID amplifiers, which are easily integrated with the detectors. These SQUID-based amplifiers and multiplexers have matured with the detectors; they are convenient to use, and have excellent noise performance. The first generation of fully integrated large scale superconducting detection systems are now being deployed. I will discuss the prospects for a new generation of instruments designed to take full advantage of the revolution in detector technology.

  12. Advanced Gravitational Wave Detectors

    NASA Astrophysics Data System (ADS)

    Blair, D. G.; Howell, E. J.; Ju, L.; Zhao, C.

    2012-02-01

    Part I. An Introduction to Gravitational Wave Astronomy and Detectors: 1. Gravitational waves D. G. Blair, L. Ju, C. Zhao and E. J. Howell; 2. Sources of gravitational waves D. G. Blair and E. J. Howell; 3. Gravitational wave detectors D. G. Blair, L. Ju, C. Zhao, H. Miao, E. J. Howell, and P. Barriga; 4. Gravitational wave data analysis B. S. Sathyaprakash and B. F. Schutz; 5. Network analysis L. Wen and B. F. Schutz; Part II. Current Laser Interferometer Detectors: Three Case Studies: 6. The Laser Interferometer Gravitational-Wave Observatory P. Fritschel; 7. The VIRGO detector S. Braccini; 8. GEO 600 H. Lück and H. Grote; Part III. Technology for Advanced Gravitational Wave Detectors: 9. Lasers for high optical power interferometers B. Willke and M. Frede; 10. Thermal noise, suspensions and test masses L. Ju, G. Harry and B. Lee; 11. Vibration isolation: Part 1. Seismic isolation for advanced LIGO B. Lantz; Part 2. Passive isolation J-C. Dumas; 12. Interferometer sensing and control P. Barriga; 13. Stabilizing interferometers against high optical power effects C. Zhao, L. Ju, S. Gras and D. G. Blair; Part IV. Technology for Third Generation Gravitational Wave Detectors: 14. Cryogenic interferometers J. Degallaix; 15. Quantum theory of laser-interferometer GW detectors H. Miao and Y. Chen; 16. ET. A third generation observatory M. Punturo and H. Lück; Index.

  13. Beam Test of a Large Area nonn Silicon Strip Detector with Fast Binary Readout Electronics

    E-print Network

    Beam Test of a Large Area n­on­n Silicon Strip Detector with Fast Binary Readout Electronics Y test was carried out for the non­irradiated and the irradiated detector modules. Efficiency, noise occupancy and performance in the edge regions were analyzed using the beam test data. High efficiency

  14. Extrinsic germanium Blocked Impurity Bank (BIB) detectors

    NASA Technical Reports Server (NTRS)

    Krabach, Timothy N.; Huffman, James E.; Watson, Dan M.

    1989-01-01

    Ge:Ga blocked-impurity-band (BIB) detectors with long wavelength thresholds greater than 190 microns and peak quantum efficiencies of 4 percent, at an operating temperature of 1.8 K, have been fabricated. These proof of concept devices consist of a high purity germanium blocking layer epitaxially grown on a Ga-doped Ge substrate. This demonstration of BIB behavior in germanium enables the development of far infrared detector arrays similar to the current silicon-based devices. Present efforts are focussed on improving the chemical vapor deposition process used to create the blocking layer and on the lithographic processing required to produce monolithic detector arrays in germanium. Approaches to test the impurity levels in both the blocking and active layers are considered.

  15. The Particle-Gamma Detector GODDESS

    NASA Astrophysics Data System (ADS)

    Ratkiewicz, A.; Cizewski, J. A.; Baugher, T.; Burcher, S.; Hardy, S.; Lonsdale, S.; Shand, C.; Pain, S. D.; Marsh, I.; Jones, K. L.; Peters, W. A.; Carpenter, M. P.; Seweryniak, D.; Zhu, S.; Kozub, R. L.; Afanasieva, L.; Blackmon, J. C.

    2014-09-01

    Transfer reactions in inverse kinematics provide a powerful probe of the single-particle structure of nuclei far from stability. The Californium Rare Isotope Breeder (CARIBU) at ATLAS produces exotic nuclei near possible r-process paths and makes them available for study. Gammasphere ORRUBA: Dual Detectors for Experimental Structure Studies (GODDESS) employs the large internal geometry of the high-resolution ?-ray detector Gammasphere to instrument the large-area position-sensitive particle detector ORRUBA. This coupling of Gammasphere and ORRUBA allows high-efficiency, high-resolution measurements of surrogate reactions for neutron capture, collective excitations via inelastic scattering, pickup reactions (such as (d,t)), and stripping reactions (e.g. (d,p)). Results from commissioning measurements and plans for future experiments will be presented. This work is supported in part by the U.S. Department of Energy and the National Science Foundation.

  16. The fine grained detector readout electronics

    NASA Astrophysics Data System (ADS)

    Retičre, F.; T2K/FGD Collaboration

    2010-11-01

    The Fine Grained Detector (FGD) readout electronics was designed to record a snapshot of the detector activity before, during and after the neutrino beam spill produced by the J-PARC accelerator complex in Tokai, Japan. The FGD is a key element of T2K near detector currently being constructed. It will act as an active target detecting charged particles produced within its scintillator bars. The original feature of the FGD electronics is to readout Multi-Pixel Photon Counters by recording waveforms using Switch Capacitor Array chips (AFTER ASIC) designed for T2K Time Projection Chamber. In these proceedings, we describe the architecture of the FGD electronics. Beam results show that the physics requirements are met or exceeded. The relatively slow sampling frequency of the AFTER ASIC does not impair the timing resolution significantly. In addition, the very good efficiency of the system for detecting Michel electrons produced by pions or muons decay has been demonstrated.

  17. Long-range alpha detector (LRAD)

    SciTech Connect

    MacArthur, D.W.; McAtee, J.L.

    1991-01-01

    Historically, alpha detectors have been limited by the very short range of alpha particles in air and by relatively poor sensitivity, even if the particles are intercepted. Of necessity, these detectors are operated in a vacuum or in close proximity to the source if reasonable efficiency is desired. In our new long-range alpha detector (LRAD), alpha particles interact with the ambient air, producing ionization in the air at the rate of about 30,000 ion pairs per MeV of alpha energy. These charges can be transported over significant distances (several meters) in a moving current of air generated by a small fan. An ion chamber located in front of the fan measures the current carried by the moving ions. The LRAD-based monitor is more sensitive and more thorough than conventional monitors. We present current LRAD sensitivity limits and results, practical monitor designs, and proposed uses for LRAD monitors. 4 refs., 7 figs.

  18. Background reduction of a spherical gaseous detector

    NASA Astrophysics Data System (ADS)

    Fard, Ali Dastgheibi; Loaiza, Pia; Piquemal, Fabrice; Giomataris, Ioannis; Gray, David; Gros, Michel; Magnier, Patrick; Navick, Xavier-François; Savvidis, Ilias

    2015-08-01

    The Spherical gaseous detector (or Spherical Proportional Counter, SPC) is a novel type of detector. It consists of a large spherical volume filled with gas, using a single detection readout channel. The detector allows 100 % detection efficiency. SEDINE is a low background version of SPC installed at the Laboratoire Souterrain de Modane (LSM) underground laboratory (4800 m.w.e) looking for rare events at very low energy threshold, below 100 eV. This work presents the details on the chemical cleaning to reduce internal 210Pb surface contamination on the copper vessel and the external radon reduction achieved via circulation of pure air inside anti-radon tent. It will be also show the radon measurement of pure gases (Ar, N, Ne, etc) which are used in the underground laboratory for the low background experiments.

  19. Using standard calibrated geometries to characterize a coaxial high purity germanium gamma detector for Monte Carlo simulations

    SciTech Connect

    Graaf, E. R. van der Dendooven, P.; Brandenburg, S.

    2014-06-15

    A detector model optimization procedure based on matching Monte Carlo simulations with measurements for two experimentally calibrated sample geometries which are frequently used in radioactivity measurement laboratories results in relative agreement within 5% between simulated and measured efficiencies for a high purity germanium detector. The optimization procedure indicated that the increase in dead layer thickness is largely responsible for a detector efficiency decrease in time. The optimized detector model allows Monte Carlo efficiency calibration for all other samples of which the geometry and bulk composition is known. The presented method is a competitive and economic alternative to more elaborate detector scanning methods and results in a comparable accuracy.

  20. LHC detector upgrades

    SciTech Connect

    Dan Green

    2003-09-15

    The LHC detectors are well into their construction phase. The LHC schedule shows first beam to ATLAS and CMS in 2007. Because the LHC accelerator has begun to plan for a ten fold increase in LHC design luminosity (the SLHC or super LHC) it is none too soon to begin to think about the upgrades which will be required of the present LHC detectors. In particular, the tracking systems of ATLAS and CMS will need to be completely rebuilt. Given the time needed to do the R & D, make prototypes, and construct the new detectors and given the accelerator schedule for the SLHC, work needs to begin rather soon.

  1. Atlas Inner Detector Alignment

    NASA Astrophysics Data System (ADS)

    Bocci, A.

    2008-06-01

    The ATLAS experiment is a multi-purpose particle detector that will study high-energy particle collisions produced by the Large Hadron Collider at CERN. In order to achieve its physics goals, the ATLAS tracking requires that the positions of the silicon detector elements have to be known to a precision better than 10 ?m. Several track-based alignment algorithms have been developed for the Inner Detector. An extensive validation has been performed with simulated events and real data coming from the ATLAS. Results from such validation are reported in this paper.

  2. More realistic Monte Carlo calculations of photon detector response functions

    NASA Astrophysics Data System (ADS)

    Rogers, D. W. O.

    1982-08-01

    The Monte Carlo electron-photon simulation package EGS3 has been used to calculate response functions for a wide variety of nuclear detectors. The detectors must be cylindrical and can be encased in a jacket or shielded by a plate of arbitrary material. The detector can have inert volumes. The code, via EGS, includes all physical processes necessary for accurate calculations for incident photons above 300 keV. An error in EGS concerning terminal processing of positrons has been found and corrected. The code runs 3 to 5 times faster than CYLTRAN. The paper presents benchmark comparisons between EGS and a wide variety of previous NaI and Ge(Li) response function calculations, in particular those of ETRAN where small but systematic differences were observed above 10 MeV incident energy. The effects of detector cladding and shielding have been studied. The program quantitatively explains the effects of a 1.18 g/cm 2 Be beta absorber and qualitatively explains the 511 keV peak present for incident high energy photons. To first order it was found that only for the photopeak efficiencies can the effect of material in front of a detector be treated as a simple absorption. The reduction in the efficiency for counts within 1.5 MeV of the incident energy is considrably less than expected using only the cross section and the reduction for escape peaks is significantly more due to reflections of 511 keV photons back into the detector. Calculations of absolute Ge(Li) detector efficiency were found to be difficult due to sensitivity to inert layer parameters but relative efficiency curves were much less sensitive. Calculations are included of response functions for bismuth germanate and large NaI detectors and angular scans of Ge(Li) detectors for solid angle correction factors. Difficulties calculating electron response functions are discussed.

  3. The DUV Stability of Superlattice-Doped CMOS Detector Arrays

    NASA Technical Reports Server (NTRS)

    Hoenk, M. E.; Carver, A. G.; Jones, T.; Dickie, M.; Cheng, P.; Greer, H. F.; Nikzad, S.; Sgro, J.; Tsur, S.

    2013-01-01

    JPL and Alacron have recently developed a high performance, DUV camera with a superlattice doped CMOS imaging detector. Supperlattice doped detectors achieve nearly 100% internal quantum efficiency in the deep and far ultraviolet, and a single layer, Al2O3 antireflection coating enables 64% external quantum efficiency at 263nm. In lifetime tests performed at Applied Materials using 263 nm pulsed, solid state and 193 nm pulsed excimer laser, the quantum efficiency and dark current of the JPL/Alacron camera remained stable to better than 1% precision during long-term exposure to several billion laser pulses, with no measurable degradation, no blooming and no image memory at 1000 fps.

  4. Pendulum detector testing device

    DOEpatents

    Gonsalves, John M. (Modesto, CA)

    1997-01-01

    A detector testing device which provides consistent, cost-effective, repeatable results. The testing device is primarily constructed of PVC plastic and other non-metallic materials. Sensitivity of a walk-through detector system can be checked by: 1) providing a standard test object simulating the mass, size and material content of a weapon or other contraband, 2) suspending the test object in successive positions, such as head, waist and ankle levels, simulating where the contraband might be concealed on a person walking through the detector system; and 3) swinging the suspended object through each of the positions, while operating the detector system and observing its response. The test object is retained in a holder in which the orientation of the test device or target can be readily changed, to properly complete the testing requirements.

  5. Pendulum detector testing device

    DOEpatents

    Gonsalves, J.M.

    1997-09-30

    A detector testing device is described which provides consistent, cost-effective, repeatable results. The testing device is primarily constructed of PVC plastic and other non-metallic materials. Sensitivity of a walk-through detector system can be checked by: (1) providing a standard test object simulating the mass, size and material content of a weapon or other contraband, (2) suspending the test object in successive positions, such as head, waist and ankle levels, simulating where the contraband might be concealed on a person walking through the detector system; and (3) swinging the suspended object through each of the positions, while operating the detector system and observing its response. The test object is retained in a holder in which the orientation of the test device or target can be readily changed, to properly complete the testing requirements. 5 figs.

  6. Subspace Detectors: Theory

    SciTech Connect

    Harris, D B

    2006-07-11

    Broadband subspace detectors are introduced for seismological applications that require the detection of repetitive sources that produce similar, yet significantly variable seismic signals. Like correlation detectors, of which they are a generalization, subspace detectors often permit remarkably sensitive detection of small events. The subspace detector derives its name from the fact that it projects a sliding window of data drawn from a continuous stream onto a vector signal subspace spanning the collection of signals expected to be generated by a particular source. Empirical procedures are presented for designing subspaces from clusters of events characterizing a source. Furthermore, a solution is presented for the problem of selecting the dimension of the subspace to maximize the probability of detecting repetitive events at a fixed false alarm rate. An example illustrates subspace design and detection using events in the 2002 San Ramon, California earthquake swarm.

  7. Improved CO [lidar detector

    SciTech Connect

    Jacobson, P.L.; Busch, G.E.; Thompson, D.C.; Remelius, D.K.; Wells, F.D.

    1999-07-18

    A high sensitivity, CO{sub 2} lidar detector, based on recent advances in ultra-low noise, readout integrated circuits (ROIC), is being developed. This detector will combine a high speed, low noise focal plane array (FPA) with a dispersive grating spectrometer. The spectrometer will filter the large background flux, thereby reducing the limiting background photon shot noise. In order to achieve the desired low noise levels, the HgCdTe FPA will be cooled to {approximately}50K. High speed, short pulse operation of the lidar system should enable the detector to operate with the order of a few noise electrons in the combined detector/ ROIC output. Current receiver design concepts will be presented, along with their expected noise performance.

  8. Hybrid photon detectors

    E-print Network

    D'Ambrosio, C

    2003-01-01

    Hybrid photon detectors detect light via vacuum photocathodes and accelerate the emitted photoelectrons by an electric field towards inversely polarized silicon anodes, where they are absorbed, thus producing electron-hole pairs. These, in turn, are collected and generate electronic signals on their ohmic contacts. This review first describes the characteristic properties of the main components of hybrid photon detectors: light entrance windows, photocathodes, and silicon anodes. Then, essential relations describing the trajectories of photoelectrons in electric and magnetic fields and their backscattering from the silicon anodes are derived. Depending on their anode configurations, three families of hybrid photon detectors are presented: hybrid photomultiplier tubes with single anodes for photon counting with high sensitivity and for gamma spectroscopy; multi-anode photon detector tubes with anodes subdivided into square or hexagonal pads for position-sensitive photon detection; imaging silicon pixel array t...

  9. Modular optical detector system

    DOEpatents

    Horn, Brent A. (Livermore, CA); Renzi, Ronald F. (Tracy, CA)

    2006-02-14

    A modular optical detector system. The detector system is designed to detect the presence of molecules or molecular species by inducing fluorescence with exciting radiation and detecting the emitted fluorescence. Because the system is capable of accurately detecting and measuring picomolar concentrations it is ideally suited for use with microchemical analysis systems generally and capillary chromatographic systems in particular. By employing a modular design, the detector system provides both the ability to replace various elements of the detector system without requiring extensive realignment or recalibration of the components as well as minimal user interaction with the system. In addition, the modular concept provides for the use and addition of a wide variety of components, including optical elements (lenses and filters), light sources, and detection means, to fit particular needs.

  10. Burst diaphragm leak detector

    NASA Technical Reports Server (NTRS)

    Pascolla, J. A.

    1969-01-01

    New method replaces flowmeter approach with readily available burst diaphragm leak detector assembly mounted to all drain ports. This allows simultaneous leak detection of all flange seals under operating conditions.

  11. Ultrafast neutron detector

    DOEpatents

    Wang, C.L.

    1985-06-19

    A neutron detector of very high temporal resolution is described. It may be used to measure distributions of neutrons produced by fusion reactions that persist for times as short as about 50 picoseconds.

  12. Improved ?-? Coincidence Detector For Radioxenon Detection

    SciTech Connect

    Cooper, Matthew W.; Carman, April J.; Hayes, James C.; Heimbigner, Tom R.; Hubbard, Charles W.; Litke, Kevin E.; McIntyre, Justin I.; Morris, Scott J.; Ripplinger, Michael D.; Suarez, Reynold

    2005-08-31

    The Automated Radio-xenon Analyzer/Sampler (ARSA), built by Pacific Northwest National Laboratory (PNNL), can collect and detect several radioxenon isotopes. ARSA is very sensitive to 133Xe, 131mXe, 133mXe and 135Xe due to the compact high efficiency ?-? coincidence detector it uses. For this reason it is an excellent treaty monitoring and environmental sampling device. Although the system is shown to be both robust and reliable, based on several field tests, it is also complex due to a detailed photomultiplier tube gain matching regime. This complexity is a problem from a maintenance and quality assurance/quality control (QA/QC) standpoint. To reduce these issues a simplified ??? coincident detector has been developed. A comparison of three different well detectors has been completed. In addition, a new plastic scintillator gas cell was constructed. The new simplified detector system has been demonstrated to equal or better performance compared with the original ARSA design in spectral resolution and efficiency and significantly easier to setup and calibrate.

  13. The ATLAS Inner Detector commissioning and calibration

    NASA Astrophysics Data System (ADS)

    Aad, G.; Abbott, B.; Abdallah, J.; Abdelalim, A. A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Abreu, H.; Acharya, B. S.; Adams, D. L.; Addy, T. N.; Adelman, J.; Adorisio, C.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Ĺkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Aktas, A.; Alam, M. S.; Alam, M. A.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alviggi, M. G.; Amako, K.; Amelung, C.; Amorim, A.; Amorós, G.; Amram, N.; Anastopoulos, C.; Andeen, T.; Anders, C. F.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Angerami, A.; Anghinolfi, F.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonelli, S.; Antos, J.; Antunovic, B.; Anulli, F.; Aoun, S.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Archambault, J. P.; Arfaoui, S.; Arguin, J.-F.; Argyropoulos, T.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnault, C.; Artamonov, A.; Arutinov, D.; Asai, M.; Asai, S.; Asfandiyarov, R.; Ask, S.; Ĺsman, B.; Asner, D.; Asquith, L.; Assamagan, K.; Astvatsatourov, A.; Atoian, G.; Auerbach, B.; Augsten, K.; Aurousseau, M.; Austin, N.; Avolio, G.; Avramidou, R.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Badescu, E.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Dos Santos Pedrosa, F. Baltasar; Banas, E.; Banerjee, P.; Banerjee, S.; Banfi, D.; Bangert, A.; Bansal, V.; Baranov, S. P.; Barashkou, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barr, A. J.; Barreiro, F.; Barreiro Guimarăes da Costa, J.; Barrillon, P.; Bartoldus, R.; Bartsch, D.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Bauer, F.; Bawa, H. S.; Bazalova, M.; Beare, B.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, G. A.; Beck, H. P.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bee, C.; Begel, M.; Harpaz, S. Behar; Behera, P. K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, M.; Belloni, A.; Belotskiy, K.; Beltramello, O.; Ami, S. Ben; Benary, O.; Benchekroun, D.; Bendel, M.; Benedict, B. H.; Benekos, N.; Benhammou, Y.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernabéu, J.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertin, A.; Besana, M. I.; Besson, N.; Bethke, S.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Bingul, A.; Bini, C.; Biscarat, C.; Bitenc, U.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blocker, C.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bocci, A.; Boehler, M.; Boek, J.; Boelaert, N.; Böser, S.; Bogaerts, J. A.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Bondarenko, V. G.; Bondioli, M.; Boonekamp, M.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borroni, S.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boulahouache, C.; Bourdarios, C.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Braem, A.; Branchini, P.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brelier, B.; Bremer, J.; Brenner, R.; Bressler, S.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brodet, E.; Bromberg, C.; Brooijmans, G.; Brooks, W. K.; Brown, G.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Bucci, F.; Buchanan, J.; Buchholz, P.; Buckley, A. G.; Budagov, I. A.; Budick, B.; Büscher, V.; Bugge, L.; Bulekov, O.; Bunse, M.; Buran, T.; Burckhart, H.; Burdin, S.; Burgess, T.; Burke, S.; Busato, E.; Bussey, P.; Buszello, C. P.; Butin, F.; Butler, B.; Butler, J. M.; Buttar, C. M.; Butterworth, J. M.; Byatt, T.; Caballero, J.; Cabrera Urbán, S.; Caforio, D.; Cakir, O.; Calafiura, P.; Calderini, G.; Calfayan, P.; Calkins, R.; Caloba, L. P.; Calvet, D.; Camarri, P.; Cameron, D.; Campana, S.; Campanelli, M.; Canale, V.; Canelli, F.; Canepa, A.; Cantero, J.; Capasso, L.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Capua, M.; Caputo, R.; Caramarcu, C.; Cardarelli, R.; Carli, T.; Carlino, G.

    2010-12-01

    The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data-taking with single LHC beams and cosmic rays. The initial detector operation, hardware commissioning and in-situ calibrations are described. Tracking performance has been measured with 7.6 million cosmic-ray events, collected using a tracking trigger and reconstructed with modular pattern-recognition and fitting software. The intrinsic hit efficiency and tracking trigger efficiencies are close to 100%. Lorentz angle measurements for both electrons and holes, specific energy-loss calibration and transition radiation turn-on measurements have been performed. Different alignment techniques have been used to reconstruct the detector geometry. After the initial alignment, a transverse impact parameter resolution of 22.1ą0.9 ?m and a relative momentum resolution ? p / p=(4.83ą0.16)×10-4 GeV-1× p T have been measured for high momentum tracks.

  14. Fiber optic detector

    NASA Astrophysics Data System (ADS)

    Partin, Judy K.; Ward, Thomas E.; Grey, Alan E.

    1990-04-01

    This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  15. Fiber optic detector

    SciTech Connect

    Partin, J.K.; Ward, T.E.; Grey, A.E.

    1990-12-31

    This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  16. Silicon microstrip detectors

    NASA Astrophysics Data System (ADS)

    Montańo, Luis M.

    2006-09-01

    The main scope of this laboratory is to give the students an introduction of some special characteristics of silicon microstrip detectors. The students will perform some exercises using different instruments to appreciate the properties of these detectors, especially its great position resolution. An overview of different instruments such as an oscilloscope, wave function generator as others will be also given as important devices in any experimental laboratory.

  17. Improved gaseous leak detector

    DOEpatents

    Juravic, F.E. Jr.

    1983-10-06

    In a short path length mass-spectrometer type of helium leak detector wherein the helium trace gas is ionized, accelerated and deflected onto a particle counter, an arrangement is provided for converting the detector to neon leak detection. The magnetic field of the deflection system is lowered so as to bring the nonlinear fringe area of the magnetic field across the ion path, thereby increasing the amount of deflection of the heavier neon ions.

  18. Gaseous leak detector

    DOEpatents

    Juravic, Jr., Frank E. (Aurora, IL)

    1988-01-01

    In a short path length mass-spectrometer type of helium leak detector wherein the helium trace gas is ionized, accelerated and deflected onto a particle counter, an arrangement is provided for converting the detector to neon leak detection. The magnetic field of the deflection system is lowered so as to bring the non linear fringe area of the magnetic field across the ion path, thereby increasing the amount of deflection of the heavier neon ions.

  19. Charged-coupled detector sky surveys.

    PubMed Central

    Schneider, D P

    1993-01-01

    Sky surveys have played a fundamental role in advancing our understanding of the cosmos. The current pictures of stellar evolution and structure and kinematics of our Galaxy were made possible by the extensive photographic and spectrographic programs performed in the early part of the 20th century. The Palomar Sky Survey, completed in the 1950s, is still the principal source for many investigations. In the past few decades surveys have been undertaken at radio, millimeter, infrared, and x-ray wavelengths; each has provided insights into new astronomical phenomena (e.g., quasars, pulsars, and the 3 degrees cosmic background radiation). The advent of high quantum efficiency, linear solid-state devices, in particular charged-coupled detectors, has brought about a revolution in optical astronomy. With the recent development of large-format charged-coupled detectors and the rapidly increasing capabilities of data acquisition and processing systems, it is now feasible to employ the full capabilities of electronic detectors in projects that cover an appreciable fraction of the sky. This talk reviews the first "large scale" charged-coupled detector survey. This program, designed to detect very distant quasars, reveals the powers and limitations of charged-coupled detector surveys. PMID:11607431

  20. Optical lumped element microwave kinetic inductance detectors

    NASA Astrophysics Data System (ADS)

    Marsden, Danica; Mazin, Benjamin A.; Bumble, Bruce; Meeker, Seth; O'Brien, Kieran; McHugh, Sean; Strader, Matthew; Langman, Eric

    2012-07-01

    Microwave Kinetic Inductance Detectors, or MKIDs, have proven to be a powerful cryogenic detector technology due to their sensitivity and the ease with which they can be multiplexed into large arrays. An MKID is an energy sensor based on a photon-variable superconducting inductance in a lithographed microresonator. It is capable of functioning as both a photon detector across the electromagnetic spectrum and a particle detector. We have recently demonstrated the world's first photon-counting, energy-resolving, ultraviolet, optical, and near infrared MKID focal plane array in the ARCONS camera at the Palomar 200" telescope. Optical Lumped Element (OLE) MKID arrays have significant advantages over semiconductor detectors such as charge coupled devices (CCDs). They can count individual photons with essentially no false counts and determine the energy (to a few percent) and arrival time (to ?1?s) of every photon, with good quantum efficiency. Initial devices were degraded by substrate events from photons passing through the Titanium Nitride (TiN) material of the resonator and being absorbed in the substrate. Recent work has eliminated this issue, with a solution found to be increasing the thickness of the TiN resonator from 20 to 60 nm.

  1. Electronics for the Si detectors in APEX

    SciTech Connect

    Wilt, P.R. |; Betts, R.R.; Freer, M.

    1994-07-01

    APEX (ATLAS Positron EXperiment), a collaborative effort of ANL, FSU, MSU/NSCL, Princeton, Queen`s, Rochester, Washington and Yale, is an experiment to study positron and electron production in very heavy ion collisions. The electrons and positrons are detected with two detector arrays, each consisting of 216 1 mm thick Si PIN diodes, and their energy and time-of-flight are measured. The number of detectors and limited space made it necessary to develop a system that could efficiently process and transfer signals from the detectors to the charge sensing ADC`s and data readout electronics as well as monitor the condition of the detectors. The discussion will cover the electronics designed for the Si detectors, including the charge amplifier, ``Mother board`` for the charge amplifiers, 8 channel Shaper, 16 channel Constant Fraction Discriminator (CFD), 16 channel Peak-to-FERA (PTF) and the integration of the CFD and PTF with Charge sensing ADC`s. Function and performance of the individual modules as well as the system as a whole will be discussed.

  2. Gamma ray detector modules

    NASA Technical Reports Server (NTRS)

    Capote, M. Albert (Inventor); Lenos, Howard A. (Inventor)

    2009-01-01

    A radiation detector assembly has a semiconductor detector array substrate of CdZnTe or CdTe, having a plurality of detector cell pads on a first surface thereof, the pads having a contact metallization and a solder barrier metallization. An interposer card has planar dimensions no larger than planar dimensions of the semiconductor detector array substrate, a plurality of interconnect pads on a first surface thereof, at least one readout semiconductor chip and at least one connector on a second surface thereof, each having planar dimensions no larger than the planar dimensions of the interposer card. Solder columns extend from contacts on the interposer first surface to the plurality of pads on the semiconductor detector array substrate first surface, the solder columns having at least one solder having a melting point or liquidus less than 120 degrees C. An encapsulant is disposed between the interposer circuit card first surface and the semiconductor detector array substrate first surface, encapsulating the solder columns, the encapsulant curing at a temperature no greater than 120 degrees C.

  3. The DEAP 3600 Dark Mater Detector

    NASA Astrophysics Data System (ADS)

    Sonley, Thomas; DEAP-3600 Collaboration

    2015-04-01

    The DEAP-3600 dark matter detector consists of 3,600 kg of liquid argon contained in an ultra-pure acrylic cryogenic vessel. The experiment is located 2 km underground at SNOLAB. DEAP-3600 is entering the commissioning phase. Scintillation light from events in the detector is observed by 255 high-efficiency room temperature PMTs. Electromagnetic backgrounds, including those from argon-39, are rejected using pulse shape discrimination based on timing. Backgrounds from neutrons and alphas are mitigated by ensuring excellent radiopurity and using a high efficiency neutron shield. The DEAP-3600 background budget is 0.2 events per year allowing a cross-section sensitivity of 10-46 cm2 for scattering of Weakly Interacting Massive Particles with a 100-GeV mass in a 3-year run. In this talk, we will describe the status and physics reach, highlighting that it is expected to reach competitive sensitivity within months of the start of data collection.

  4. BF3 Neutron Detector Tests

    SciTech Connect

    Kouzes, Richard T.; Ely, James H.; Lintereur, Azaree T.; Siciliano, Edward R.; Woodring, Mitchell L.

    2009-12-09

    Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world; thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and detection capabilities are being investigated. Reported here are the results of tests of the efficiency of BF3 tubes at a pressure of 800 torr. These measurements were made partially to validate models of the RPM system that have been modified to simulate the performance of BF3-filled tubes. While BF3 could be a potential replacement for 3He, there are limitations to its use in deployed systems.

  5. Progress in semiconductor drift detectors

    SciTech Connect

    Rehak, P.; Walton, J.; Gatti, E.; Longoni, A.; Sanpietro, M.; Kemmer, J.; Dietl, H.; Holl, P.; Klanner, R.; Lutz, G.

    1985-01-01

    Progress in testing semiconductor drift detectors is reported. Generally better position and energy resolutions were obtained than resolutions published previously. The improvement is mostly due to new electronics better matched to different detectors. It is shown that semiconductor drift detectors are becoming versatile and reliable detectors for position and energy measurements.

  6. Diamond detectors in particle physics

    NASA Astrophysics Data System (ADS)

    Tapper, R. J.

    2000-08-01

    Particle detectors made from artificial diamond have great promise for future experiments in particle physics because they are far less vulnerable to radiation damage than any other detector type. We review the history of diamond detectors and describe their current state of development. We also discuss the evidence which proves the resistance of these detectors to damage by various forms of incident radiation.

  7. Nano structural anodes for radiation detectors

    DOEpatents

    Cordaro, Joseph V.; Serkiz, Steven M.; McWhorter, Christopher S.; Sexton, Lindsay T.; Retterer, Scott T.

    2015-07-07

    Anodes for proportional radiation counters and a process of making the anodes is provided. The nano-sized anodes when present within an anode array provide: significantly higher detection efficiencies due to the inherently higher electric field, are amenable to miniaturization, have low power requirements, and exhibit a small electromagnetic field signal. The nano-sized anodes with the incorporation of neutron absorbing elements (e.g., .sup.10B) allow the use of neutron detectors that do not use .sup.3He.

  8. Microchannel Plate Imaging Detectors for the Ultraviolet

    NASA Technical Reports Server (NTRS)

    Siegmund, O. H. W.; Gummin, M. A.; Stock, J.; Marsh, D.

    1992-01-01

    There has been significant progress over the last few years in the development of technologies for microchannel plate imaging detectors in the Ultraviolet (UV). Areas where significant developments have occurred include enhancements of quantum detection efficiency through improved photocathodes, advances in microchannel plate performance characteristics, and development of high performance image readout techniques. The current developments in these areas are summarized, with their applications in astrophysical instrumentation.

  9. The PHENIX Hadron Blind Detector

    SciTech Connect

    Durham, J. M.

    2009-03-10

    Dielectron measurements by the PHENIX Experiment at RHIC are limited by the combinatorial background from electrons and positrons which are not produced in the same pair. The Hadron Blind Detector will allow a substantial reduction of this background by correctly identifying dielectrons from photon conversions and pion Dalitz decays which dominate the signal in the low mass region of the spectrum. Triple GEM stacks, with a CsI photocathode deposited on the uppermost GEM, detect Cherenkov light produced by electrons in a CF{sub 4} radiator. The transparency of CF{sub 4}, high quantum efficiency of CsI in the UV, and absence of a window between the gas radiator and the GEMs allow a large photoelectron yield, while minimizing the hadron signal. Results from the HBD in RHIC's Run-7 and preparations for upcoming runs are discussed.

  10. The PANDA Barrel DIRC detector

    NASA Astrophysics Data System (ADS)

    Hoek, M.; Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Hohler, R.; Kalicy, G.; Kumawat, H.; Lehmann, D.; Lewandowski, B.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Zühlsdorf, M.; Dodokhov, V. Kh.; Britting, A.; Eyrich, W.; Lehmann, A.; Uhlig, F.; Düren, M.; Föhl, K.; Hayrapetyan, A.; Kröck, B.; Merle, O.; Rieke, J.; Cowie, E.; Keri, T.; Montgomery, R.; Rosner, G.; Achenbach, P.; Cardinali, M.; Lauth, W.; Sfienti, C.; Thiel, M.; Bühler, P.; Gruber, L.; Marton, J.; Suzuki, K.

    2014-12-01

    The PANDA experiment at the new Facility for Antiproton and Ion Research in Europe (FAIR) at GSI, Darmstadt, will study fundamental questions of hadron physics and QCD using high-intensity cooled antiproton beams with momenta between 1.5 and 15 GeV/c. Efficient Particle Identification for a wide momentum range and the full solid angle is required for reconstructing the various physics channels of the PANDA program. Hadronic Particle Identification in the barrel region of the detector will be provided by a DIRC counter. The design is based on the successful BABAR DIRC with important improvements, such as focusing optics and fast photon timing. Several of these improvements, including different radiator geometries and optics, were tested in particle beams at GSI and at CERN. The evolution of the conceptual design of the PANDA Barrel DIRC and the performance of complex prototypes in test beam campaigns will be discussed.

  11. Gamma-ray fast-timing coincidence measurements from the 18O+18O fusion-evaporation reaction using a mixed LaBr3-HPGe array.

    PubMed

    Alharbi, T; Mason, P J R; Regan, P H; Podolyák, Zs; M?rginean, N; Nakhostin, M; Bowry, M; Bucurescu, D; C?ta-Danil, G; C?ta-Danil, I; Deleanu, D; Filipescu, D; Glodariu, T; Ghi??, D; M?rginean, R; Mihai, C; Negret, A; Pascu, S; Sava, T; Stroe, L; Suliman, G; Zamfir, N V; Bruce, A M; Rodriguez Triguero, C; Bender, P C; Garg, U; Erduran, M N; Kusoglu, A; Bostan, M; Detistov, P; Alkhomashi, N; Sinha, A K; Chakrabarti, R; Ghugre, S S

    2012-07-01

    We report on a gamma-ray coincidence analysis using a mixed array of hyperpure germanium and cerium-doped lanthanum tri-bromide (LaBr3:Ce) scintillation detectors to study nuclear electromagnetic transition rates in the pico-to-nanosecond time regime in 33,34P and 33S following fusion-evaporation reactions between an 18O beam and an isotopically enriched 18O implanted tantalum target. Energies from decay gamma-rays associated with the reaction residues were measured in event-by-event coincidence mode, with the measured time difference information between the pairs of gamma-rays in each event also recorded using the ultra-fast coincidence timing technique. The experiment used the good full-energy peak resolution of the LaBr3:Ce detectors coupled with their excellent timing responses in order to determine the excited state lifetime associated with the lowest lying, cross-shell, I?=4- "intruder" state previously reported in the N=19 isotone 34P. The extracted lifetime is consistent with a mainly single-particle M2 multipolarity associated with a f7/2?d5/2 single particle transition. PMID:22154387

  12. An efficient method for the simultaneous determination of furan, 2-methylfuran and 2-pentylfuran in fruit juices by headspace solid phase microextraction and gas chromatography-flame ionisation detector.

    PubMed

    Hu, Gaofei; Zhu, Yan; Hernandez, Marta; Koutchma, Tatiana; Shao, Suqin

    2016-02-01

    A headspace solid phase microextraction (HS-SPME) procedure followed by gas chromatography-flame ionisation detector (GC-FID) analysis was developed and validated for the simultaneous analysis of furan, 2-methylfuran and 2-pentylfuran from juice samples. Extraction at 32 °C for 20 min with stirring at 600 rpm and NaCl concentration 15% (W/V) was the optimal HS-SPME condition for all the three compounds by using a carboxen/polydimethylsiloxane fused silica fibre (75 ?m). The extracted compounds were base line separated on a SPB-1 GC column within 12 min. The relative standard deviations of all analytes were less than 6.7%. The recovery rates were between 90.2% and 110.1%. The limits of detection and limits of quantification were 0.056-0.23 ng/mL and 0.14-0.76 ng/mL, respectively. The results showed that the developed method was sensitive, precise, accurate and robust for the determination of furan, 2-methylfuran and 2-pentylfuran in complex matrices without interferences from other components. PMID:26304314

  13. Two dimensional and linear scintillation detectors for fast neutron imaging — comparative analysis

    NASA Astrophysics Data System (ADS)

    Mikerov, V. I.; Koshelev, A. P.; Ozerov, O. V.; Sviridov, A. S.; Yurkov, D. I.

    2014-05-01

    The paper was aimed to compare performance capabilities of two types of scintillation detectors commonly used for fast neutron imaging: two dimensional and linear ones. Best-case values of quantum efficiency, spatial resolution and capacity were estimated for detectors with plastic converter-screen in case of 14 MeV neutrons. For that there were examined nuclear reactions produced in converter-screen by fast neutrons, spatial distributions of energy release of emerged charged particles and amplitude distributions of scintillations generated by these particles. The paper shows that the efficiency of the linear detector is essentially higher and this detector provides potentially better spatial resolution in comparison with the two dimensional detector. But, the two dimensional detector surpasses the linear one in capacity. The presented results can be used for designing radiographic fast neutron detectors with organic scintillators.

  14. Development of lightning current detector

    NASA Technical Reports Server (NTRS)

    Livermore, S.

    1976-01-01

    A lightning current detector to record the maximum current amplitude of a lightning strike to the 150 meter weather tower at KSC was developed. The principle of operation of the detector is discussed, materials chosen to build the detector are described, and calibration tests performed on the detector are given. Field results of the detectors from two separate lightning strikes to the tower are included.

  15. Velocity map imaging using an in-vacuum pixel detector

    SciTech Connect

    Gademann, Georg; Huismans, Ymkje; Gijsbertsen, Arjan; Jungmann, Julia; Vrakking, Marc J. J.; Visschers, Jan

    2009-10-15

    The use of a new type in-vacuum pixel detector in velocity map imaging (VMI) is introduced. The Medipix2 and Timepix semiconductor pixel detectors (256x256 square pixels, 55x55 {mu}m{sup 2}) are well suited for charged particle detection. They offer high resolution, low noise, and high quantum efficiency. The Medipix2 chip allows double energy discrimination by offering a low and a high energy threshold. The Timepix detector allows to record the incidence time of a particle with a temporal resolution of 10 ns and a dynamic range of 160 {mu}s. Results of the first time application of the Medipix2 detector to VMI are presented, investigating the quantum efficiency as well as the possibility to operate at increased background pressure in the vacuum chamber.

  16. Non-equilibrium dynamics in superconducting tunnel junction detectors

    SciTech Connect

    Hiller, L.J.; Labov, S.E.; Mears, C.A.; Frank, M.; Bello, A.F.; Barfknecht, A.T.

    1994-12-09

    Superconducting tunnel junctions have the potential to serve as high-resolution, high-efficiency x-ray detectors for astrophysical and industrial applications. When irradiated by X rays, each X ray excites over 10{sup 6} charge carriers which cause the detector to generate a pulse of current. We present an analysis of pulse shapes from detectors we have constructed and operated. We fit the decay of the current pulse to a simple model that considers two classes of carrier loss. One model considers only the normal recombination of the charge carriers with themselves, the other included additional losses due to recombination sites in the within the detector medium. We found that both mechanisms most be taken into account. We also found a small variation in pulse shape depending on which layer of the tunnel junction absorbed the X ray. We expect that this analysis will be a useful tool in comparing different detector designs and operating conditions.

  17. A passive FPAA based RF scatter meteor detector

    E-print Network

    Popowicz, Adam; Bernacki, Krzysztof; Fietkiewicz, Karol

    2015-01-01

    In the article we present a hardware meteor detector. The detection principle is based on the electromagnetic wave reflection from the ionized meteor trail in the atmosphere. The detector uses the ANADIGM field programmable analogue array (FPAA), which is an attractive alternative for a typically used detecting equipment - a PC computer with dedicated software. We implement an analog signal path using most of available FPAA resources to obtain precise audio signal detection. Our new detector was verified in collaboration with the Polish Fireball Network - the organization which monitors meteor activity in Poland. When compared with currently used signal processing PC software employing real radio meteor scatter signals, our low-cost detector proved to be more precise and reliable. Due to its cost and efficiency superiority over the current solution, the presented module is going to be implemented in the planned distributed detectors system.

  18. Development of an advanced antineutrino detector for reactor monitoring

    NASA Astrophysics Data System (ADS)

    Classen, T.; Bernstein, A.; Bowden, N. S.; Cabrera-Palmer, B.; Ho, A.; Jonkmans, G.; Kogler, L.; Reyna, D.; Sur, B.

    2015-01-01

    Here we present the development of a compact antineutrino detector for the purpose of nuclear reactor monitoring, improving upon a previously successful design. This paper will describe the design improvements of the detector which increases the antineutrino detection efficiency threefold over the previous effort. There are two main design improvements over previous generations of detectors for nuclear reactor monitoring: dual-ended optical readout and single volume detection mass. The dual-ended optical readout eliminates the need for fiducialization and increases the uniformity of the detector's optical response. The containment of the detection mass in a single active volume provides more target mass per detector footprint, a key design criteria for operating within a nuclear power plant. This technology could allow for real-time monitoring of the evolution of a nuclear reactor core, independent of reactor operator declarations of fuel inventories, and may be of interest to the safeguards community.

  19. A high resolution semiconductor detector for applications in space

    NASA Technical Reports Server (NTRS)

    Alexander, P.; Shulman, H.

    1972-01-01

    Nuclear radiation detectors with volumes of approximately 1 cu cm was fabricated from single crystals of germanium-silicon alloy containing as much as 20 weight percent germanium. The properties of these detectors were investigated and will be discussed. Tests reveal that the gamma ray photoelectric peak efficiency of an alloy detector with only 12 weight percent germanium is approximately 4 times that of a silicon detector of equal volume. The room temperature roomure appears to be a good possibility. Storage for long periods at room temperature does not seem to adversely affect these devices. The results of preliminary radiation damage experiments suggest that the alloy detectors possess a radiation damage resistance far greater than that of silicon.

  20. Neutron-burst detectors for cold-fusion experiments

    NASA Astrophysics Data System (ADS)

    Menlove, H. O.; Miller, M. C.

    1990-12-01

    We have designed several neutron detectors for use in measuring neutrons from cold-fusion experiments. The high-efficiency detectors are based on 3He gas tubes in a CH 2 moderator. The total efficiency of our most advanced detector for 2.3 MeV ( 252Cf) neutrons is 44%. The detector consists of two independent segments making up inner and outer rings of 3He tubes. The inner detector has nine 3He tubes and the outer detector has 42 3He tubes. The low-background inner detector has a singles count background of 97 counts/h and a coincidence count background of only 0.7 counts/h. The corresponding singles efficiency is 19%. The inside ring of tubes is undermoderated and it is more sensitive to lower-energy source neutrons. The outside ring of tubes is overmoderated and thus more sensitive to high-energy neutrons. The ratio of the outside tubes to the inside tubes gives the approximate average neutron energy based on differential transmission as a function of energy. Monte Carlo transport calculations have been performed to establish the energy calibration of the outside/inside tube-ring ratio. The time-correlation (coincidence) information is required to investigate neutron pulsing, bursts and other nonrandom emissions caused by nonequilibrium conditions and instabilities in the samples. The time correlations in our detector are obtained by using the shift register-type electronic circuitry. Our detector system has been applied successfully to the measurement of neutron yield and multiplicity distribution from cold-fusion electrolysis samples and D 2-gas-type samples.

  1. Neutron detectors comprising ultra-thin layers of boron powder

    DOEpatents

    Wang, Zhehul; Morris, Christopher

    2013-07-23

    High-efficiency neutron detector substrate assemblies comprising a first conductive substrate, wherein a first side of the substrate is in direct contact with a first layer of a powder material having a thickness of from about 50 nm to about 250 nm and comprising .sup.10boron, .sup.10boron carbide or combinations thereof, and wherein a conductive material is in proximity to the first layer of powder material; and processes of making said neutron detector substrate assemblies.

  2. Measuring module of the Cherenkov water detector NEVOD

    NASA Astrophysics Data System (ADS)

    Kindin, V. V.; Amelchakov, M. B.; Barbashina, N. S.; Bogdanov, A. G.; Burtsev, V. D.; Chernov, D. V.; Khokhlov, S. S.; Khomyakov, V. A.; Kokoulin, R. P.; Kompaniets, K. G.; Kovylyaeva, E. A.; Kruglikova, V. S.; Ovchinnikov, V. V.; Petrukhin, A. A.; Shulzhenko, I. A.; Shutenko, V. V.; Yashin, I. I.; Zadeba, E. A.

    2015-08-01

    Quasispherical Module (QSM) of Cherenkov water detector NEVOD represents six low-noise FEU-200 photomultipliers with flat photocathodes (15 cm in diameter), oriented along the axes of orthogonal coordinate system. Such configuration allows to register Cherenkov radiation arriving from any direction with almost equal efficiency. The results of measurements of QSM characteristics in the sensitive volume of the NEVOD detector during the registration of Cherenkov radiation of single muons at different distances and angles are discussed.

  3. An integrated atom detector: single atoms and photon statistics

    E-print Network

    Heine, Dennis; Raub, Thomas; Hessmo, Björn; Schmiedmayer, Jörg; 10.1103/PhysRevA.79.021804

    2009-01-01

    We demonstrate a robust fiber-optics-based fluorescence detector, fully integrated on an atom chip, which detects single atoms propagating in a guide with 66% efficiency. We characterize the detector performance and the atom flux by analyzing the photon statistics. Near-perfect photon antibunching proves that single atoms are detected, and allows us to study the second-order intensity correlation function of the fluorescence over three orders of magnitude in atomic density.

  4. An integrated atom detector: single atoms and photon statistics

    E-print Network

    Dennis Heine; Marco Wilzbach; Thomas Raub; Björn Hessmo; Jörg Schmiedmayer

    2009-03-23

    We demonstrate a robust fiber-optics-based fluorescence detector, fully integrated on an atom chip, which detects single atoms propagating in a guide with 66% efficiency. We characterize the detector performance and the atom flux by analyzing the photon statistics. Near-perfect photon antibunching proves that single atoms are detected, and allows us to study the second-order intensity correlation function of the fluorescence over three orders of magnitude in atomic density.

  5. Direct test of quantum nonlocality using inefficient photon number detectors

    E-print Network

    Lee, Seung-Woo; Jaksch, Dieter

    2009-01-01

    We derive a Bell inequality for detecting non-local correlations in continuous variable systems directly from measurement results obtained with imperfect photon number detectors. We find that detectors with a photon detection efficiency as low as 50% can yield strong violations of local realistic theories for single photon and two-mode squeezed states. This study opens up the possibility of direct tests of quantum non-locality using current technologies.

  6. Directional Cerenkov Detectors

    NASA Astrophysics Data System (ADS)

    Norbeck, Edwin; Onel, Yasar; Bruecken, Peter; Miller, Mitch; Premo, Nathan

    2008-10-01

    It is sometimes useful to have a particle detector that determines not only the amount of energy deposited in the detector but also the direction from which it came. With a colliding beam machine, such as the LHC, at small angles a detector is exposed both to particles coming from the interaction region and to particles produced by incoming beam particles. A directional detector can identify and enable the elimination of the background from the incoming beam. A charged particle with the velocity of light passing through a medium with an index of refraction n emits (Cerenkov) light at an angle ?c with respect to its direction such that cos?c = 1/n. This angle is 45^o for n = 1.414. Directional counters can be made by using the directional properties of the Cerenkov light. A photomultiplier tube, by itself, acts as such a detector by responding to Cerenkov light produced in the glass over the photocathode. Various counter configurations have been studied using cosmic- ray muons identified by cosmic-ray telescopes from the NSF-DOE QuarkNet program. These counters are candidates for Forward Shower Counters (FSC) for the CMS experiment at the LHC.

  7. Negative Avalanche Feedback Detectors for Photon-Counting Optical Communications

    NASA Technical Reports Server (NTRS)

    Farr, William H.

    2009-01-01

    Negative Avalanche Feedback photon counting detectors with near-infrared spectral sensitivity offer an alternative to conventional Geiger mode avalanche photodiode or phototube detectors for free space communications links at 1 and 1.55 microns. These devices demonstrate linear mode photon counting without requiring any external reset circuitry and may even be operated at room temperature. We have now characterized the detection efficiency, dark count rate, after-pulsing, and single photon jitter for three variants of this new detector class, as well as operated these uniquely simple to use devices in actual photon starved free space optical communications links.

  8. Performance of a long plastic scintillator detector for neutron studies

    NASA Astrophysics Data System (ADS)

    Celano, L.; Tagliente, G.; D'Erasmo, G.; Pantaleo, A.; Colonna, N.; Fiore, E. M.; Rui, R.

    1997-02-01

    We present the performance of a very long position-sensitive plastic scintillator detector, to be used in hypernuclei studies with the Finuda apparatus at the Da?ne accelerator of Frascati, Italy. The detector response to neutrons of 40 < E < 100 MeV was measured in a dedicated experiment at Triumf, Vancouver. By comparing the measured response functions with the results of a Geant-based simulation, we have estimated the detector efficiency as a function of energy, light output threshold and impact position.

  9. New Generation of Superconducting Nanowire Single-Photon Detectors

    NASA Astrophysics Data System (ADS)

    Goltsman, G. N.

    2015-09-01

    We present an overview of recent results for new generation of infrared and optical superconducting nanowire single-photon detectors (SNSPDs) that has already demonstrated a performance that makes them devices-of-choice for many applications. SNSPDs provide high efficiency for detecting individual photons while keeping dark counts and timing jitter minimal. Besides superior detection performance over a broad optical bandwidth, SNSPDs are also compatible with an integrated optical platform as a crucial requirement for applications in emerging quantum photonic technologies. By embedding SNSPDs in nanophotonic circuits we realize waveguide integrated single photon detectors which unite all desirable detector properties in a single device.

  10. Radiation detectors as surveillance monitors for IAEA safeguards

    SciTech Connect

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

    1980-10-01

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

  11. Experimental Characterization of Space Charge in IZIP Detectors

    SciTech Connect

    Doughty, T; Pyle, M.; Mirabolfathi, N.; Serfass, B.; Kamaev, O.; Hertel, S.; Leman, S.W.; Brink, P.; Cabrera, B.; 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.

  12. Detector driver systems and photometric estimates for RIMAS

    NASA Astrophysics Data System (ADS)

    Toy, Vicki L.; Kutyrev, Alexander S.; Lyness, Eric I.; Muench, Marius; Robinson, Frederick D.; Lotkin, Gennadiy N.; Capone, John I.; Veilleux, Sylvain; Moseley, Samuel H.; Gehrels, Neil A.; Vogel, Stuart N.

    2014-07-01

    The Rapid infrared IMAger-Spectrometer (RIMAS) is a rapid gamma-ray burst afterglow instrument that will provide photometric and spectroscopic coverage of the Y, J, H, and K bands. RIMAS separates light into two optical arms, YJ and HK, which allows for simultaneous coverage in two photometric bands. RIMAS utilizes two 2048 x 2048 pixel Teledyne HgCdTe (HAWAII-2RG) detectors along with a Spitzer Legacy Indium- Antimonide (InSb) guiding detector in spectroscopic mode to position and keep the source on the slit. We describe the software and hardware development for the detector driver and acquisition systems. The HAWAII- 2RG detectors simultaneously acquire images using Astronomical Research Cameras, Inc. driver, timing, and processing boards with two C++ wrappers running assembly code. The InSb detector clocking and acquisition system runs on a National Instruments cRIO-9074 with a Labview user interface and clocks written in an easily alterable ASCII file. We report the read noise, linearity, and dynamic range of our guide detector. Finally, we present RIMAS's estimated instrument efficiency in photometric imaging mode (for all three detectors) and expected limiting magnitudes. Our efficiency calculations include atmospheric transmission models, filter models, telescope components, and optics components for each optical arm.

  13. nGEM fast neutron detectors for beam diagnostics

    NASA Astrophysics Data System (ADS)

    Croci, G.; Claps, G.; Cavenago, M.; Dalla Palma, M.; Grosso, G.; Murtas, F.; Pasqualotto, R.; Perelli Cippo, E.; Pietropaolo, A.; Rebai, M.; Tardocchi, M.; Tollin, M.; Gorini, G.

    2013-08-01

    Fast neutron detectors with a sub-millimetric space resolution are required in order to qualify neutron beams in applications related to magnetically-controlled nuclear fusion plasmas and to spallation sources. A nGEM detector has been developed for the CNESM diagnostic system of the SPIDER NBI prototype for ITER and as beam monitor for fast neutrons lines at spallation sources. The nGEM is a triple GEM gaseous detector equipped with polypropylene and polyethylene layers used to convert fast neutrons into recoil protons through the elastic scattering process. This paper describes the results obtained by testing a nGEM detector at the ISIS spallation source on the VESUVIO beam line. Beam profiles (?x=14.35 mm, ?y=15.75 mm), nGEM counting efficiency (around 10-4 for 3 MeVdetector stability (?4.5%) and the effect of filtering the beam with different type of materials were successfully measured. The x beam profile was compared to the one measured by a single crystal diamond detector. Finally, the efficiency of the detector was simulated exploiting the GEANT4 tool.

  14. Solid xenon radiation detectors

    NASA Astrophysics Data System (ADS)

    Dolinski, Michelle J.

    2014-03-01

    Cryogenic liquid xenon detectors have become a popular technology in the search for rare events, such as dark matter interactions and neutrinoless double beta decay. The power of the liquid xenon detector technology is in the combination of the ionization and scintillation signals, resulting in particle discrimination and improved energy resolution over the ionization-only signal. The improved energy resolution results from a unique anti-correlation phenomenon that has not been described from first principles. Solid xenon bolometers, under development at Drexel University, are expected to have excellent counting statistics in the phonon channel, with energy resolution of 0.1% or better. This additional energy channel may offer the final piece of the puzzle in understanding liquid xenon detector energy response. Supported by a grant from the Charles E. Kaufman Foundation.

  15. Semiconductor radiation detector

    DOEpatents

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

    2002-01-01

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

  16. Handheld CZT radiation detector

    DOEpatents

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

    2004-08-24

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

  17. High-resolution microcalorimeter detectors as a tool in the future of nuclear safeguards

    SciTech Connect

    Hoteling, Nathan J; Hoover, Andrew S

    2010-01-01

    New measurements are presented from the LANL-NIST microcalorimeter array for two standard plutonium sources. The results demonstrate substantially smaller error bars obtained from the spectral analysis program FRAM. Some areas of improvement to the analysis technique have been identified, indicating that the micro calorimeter results can be improved upon. These results support the viability of a device for performing real nuclear safeguards measurements in the near future. The challenge of providing reliably accurate and precise data is a critical component of any safeguards initiative. In the realm of nuclear safeguards, this is an especially daunting task since inaccurate and/or imprecise data could have very serious international consequences. As such, there is a constant drive within the community to establish better measurement and analysis techniques in order to further reduce the associated errors and uncertainties. Even with todays state of the art equipment, measurement uncertainties can extend to several significant quantities worth of material over a relatively modest period of time. Furthermore, there is a strong desire for improved nondestructive analysis techniques in order to reduce both the cost, turnover rate, and inconvenience of destructive analyses. One promising new technology that may help to realize these goals is that of gamma-ray microcalorimeter detectors. The hallmark quality of this new technique is the ability to achieve energy resolution nearly an order of magnitude better than typical planar high-purity germanium (HPGe) detectors. Such an improvement may help reduce uncertainties associated with, for instance, plutonium isotopics or uranium enrichment measurements. This may, in turn, help to reduce uncertainties in total plutonium and/or uranium content in a given sample without the need for destructive analysis. In this paper, we will describe this new detector technology as well as some recent measurements carried out with the LANL-NIST gamma-ray microcalorimeter ({micro}cal) array. Discussion will focus on the capabilities of this technology as well as the progress toward a practical measurement device.

  18. Radiation Detectors and Art

    NASA Astrophysics Data System (ADS)

    Denker, Andrea

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

  19. Fissile material detector

    DOEpatents

    Ivanov, Alexander I. (Dubna, RU); Lushchikov, Vladislav I. (Dubna, RU); Shabalin, Eugeny P. (Dubna, RU); Maznyy, Nikita G. (Dubna, RU); Khvastunov, Michael M. (Dubna, RU); Rowland, Mark (Alamo, CA)

    2002-01-01

    A detector for fissile materials which provides for integrity monitoring of fissile materials and can be used for nondestructive assay to confirm the presence of a stable content of fissile material in items. The detector has a sample cavity large enough to enable assay of large items of arbitrary configuration, utilizes neutron sources fabricated in spatially extended shapes mounted on the endcaps of the sample cavity, incorporates a thermal neutron filter insert with reflector properties, and the electronics module includes a neutron multiplicity coincidence counter.

  20. Glow discharge detector

    DOEpatents

    Koo, Jackson C. (San Ramon, CA); Yu, Conrad M. (Antioch, CA)

    2002-01-01

    A highly sensitive electronic ion cell for the measurement of trace elements in He carrier gas which involves glow discharge. A constant wave (CW) glow discharge detector which is controlled through a biased resistor, can detect the change of electron density caused by impurities in the He carrier gas by many orders of magnitude larger than that caused by direct ionization or electron capture. The glow discharge detector utilizes a floating pseudo-electrode to form a probe in or near the plasma. By using this probe, the large variation of electron density due to trace amounts of impurities can be directly measured.

  1. The Advanced Virgo detector

    NASA Astrophysics Data System (ADS)

    Acernese, F.; Adams, T.; Agathos, M.; Agatsuma, K.; Allocca, A.; Astone, P.; Ballardin, G.; Barone, F.; Barsuglia, M.; Basti, A.; Bauer, Th S.; Bavigadda, V.; Bejger, M.; Belczynski, C.; Bersanetti, D.; Bertolini, A.; Bitossi, M.; Bizouard, M. A.; Bloemen, S.; Boer, M.; Bogaert, G.; Bondu, F.; Bonelli, L.; Bonnand, R.; Boschi, V.; Bosi, L.; Bradaschia, C.; Branchesi, M.; Briant, T.; Brillet, A.; Brisson, V.; Bulik, T.; Bulten, H. J.; Buskulic, D.; Buy, C.; Cagnoli, G.; Calloni, E.; Carbognani, F.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cesarini, E.; Chassande-Mottin, E.; Chincarini, A.; Chiummo, A.; Chua, S.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Colombini, M.; Conte, A.; Coulon, J.-P.; Cuoco, E.; D'Antonio, S.; Dattilo, V.; Davier, M.; Day, R.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Dereli, H.; De Rosa, R.; Di Fiore, L.; Di Lieto, A.; Di Virgilio, A.; Dolique, V.; Drago, M.; Ducrot, M.; Endr?czi, G.; Fafone, V.; Farinon, S.; Ferrante, I.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Flaminio, R.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Gammaitoni, L.; Garufi, F.; Gatto, A.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; Ghosh, S.; Giazotto, A.; Gouaty, R.; Granata, M.; Greco, G.; Groot, P.; Guidi, G. M.; Harms, J.; Heidmann, A.; Heitmann, H.; Hello, P.; Hemming, G.; Hofman, D.; Jonker, R. J. G.; Kasprzack, M.; Kéfélian, F.; Królak, A.; Kutynia, A.; Lazzaro, C.; Lebigot, E.; Leonardi, M.; Leroy, N.; Letendre, N.; Lorenzini, M.; Loriette, V.; Losurdo, G.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mangano, V.; Mantovani, M.; Marchesoni, F.; Marion, F.; Marque, J.; Martelli, F.; Martinelli, L.; Masserot, A.; Meacher, D.; Meidam, J.; Mezzani, F.; Michel, C.; Milano, L.; Minenkov, Y.; Moggi, A.; Mohan, M.; Mours, B.; Nagy, M. F.; Nardecchia, I.; Naticchioni, L.; Nelemans, G.; Neri, I.; Neri, M.; Nocera, F.; Palomba, C.; Paoletti, F.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Pichot, M.; Piergiovanni, F.; Pillant, G.; Pinard, L.; Poggiani, R.; Prijatelj, M.; Prodi, G. A.; Punturo, M.; Puppo, P.; Rabeling, D. S.; Rácz, I.; Rapagnani, P.; Razzano, M.; Re, V.; Regimbau, T.; Ricci, F.; Robinet, F.; Rocchi, A.; Rolland, L.; Romano, R.; Ruggi, P.; Sassolas, B.; Sentenac, D.; Sequino, V.; Shah, S.; Siellez, K.; Straniero, N.; Swinkels, B.; Tacca, M.; Tonelli, M.; Travasso, F.; Vajente, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Sluys, M. V.; van Heijningen, J.; Vasúth, M.; Vedovato, G.; Veitch, J.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinet, J.-Y.; Vocca, H.; Wei, L.-W.; Yvert, M.; Zadro?ny, A.; Zendri, J.-P.

    2015-05-01

    The Advanced Virgo interferometer is the upgraded version of the Virgo detector having the goal to extend by a factor 10 the observation horizon in the universe and consequently increase the detection rate by three orders of magnitude. Its installation is in progress and is expected to be completed in late 2015. In this proceeding we will present the scheme and the main challenging technical features of the detector and we will give an outline of the installation status and the foreseen time schedule which will bring Advanced Virgo to its full operation.

  2. Ultrasonic liquid level detector

    DOEpatents

    Kotz, Dennis M. (North Augusta, SC); Hinz, William R. (Augusta, GA)

    2010-09-28

    An ultrasonic liquid level detector for use within a shielded container, the detector being tubular in shape with a chamber at its lower end into which liquid from in the container may enter and exit, the chamber having an ultrasonic transmitter and receiver in its top wall and a reflector plate or target as its bottom wall whereby when liquid fills the chamber a complete medium is then present through which an ultrasonic wave may be transmitted and reflected from the target thus signaling that the liquid is at chamber level.

  3. Semiconductor neutron detector

    DOEpatents

    Ianakiev, Kiril D. (Los Alamos, NM); Littlewood, Peter B. (Cambridge, GB); Blagoev, Krastan B. (Arlington, VA); Swinhoe, Martyn T. (Los Alamos, NM); Smith, James L. (Los Alamos, NM); Sullivan, Clair J. (Los Alamos, NM); Alexandrov, Boian S. (Los Alamos, NM); Lashley, Jason Charles (Santa Fe, NM)

    2011-03-08

    A neutron detector has a compound of lithium in a single crystal form as a neutron sensor element. The lithium compound, containing improved charge transport properties, is either lithium niobate or lithium tantalate. The sensor element is in direct contact with a monitor that detects an electric current. A signal proportional to the electric current is produced and is calibrated to indicate the neutrons sensed. The neutron detector is particularly useful for detecting neutrons in a radiation environment. Such radiation environment may, e.g. include gamma radiation and noise.

  4. Future water Cherenkov detectors

    SciTech Connect

    Bergevin, Marc

    2015-05-15

    In these proceedings a review of the current proposed large-scale Warer Cherenkov experiments is given. An argument is made that future water Cherenkov detectors would benefit in the investment in neutron detection technology. A brief overview will be given of proposed water Cherenkov experiments such as HYPER-K and MEMPHYS and other R and D experiments to demonstrate neutron capture in water Cherenkov detectors. Finally, innovation developed in the context of the now defunct LBNE Water R and D option to improve Water Cherenkov technology will be described.

  5. Cosmic ray detectors

    NASA Technical Reports Server (NTRS)

    Gregory, John C.

    1987-01-01

    Work on the MSFC emulsion laboratory microscopes in which mechanical modifications previously made were verified is reviewed, as is a design study of a large area hybrid electronic/emulsion chamber balloon flight detector system. This design is built upon the experience obtained with the highly successful MSFC/UAH hybrid instrument flown by the JACEE consortium. The design included overall system design and specification, design and fabrication of a prototype large light diffusion for Cerenkov charge detector or scintillator, design of a multiwire proportional counter array and design of the gondola or flight support system.

  6. Intelligent Detector Design

    SciTech Connect

    Graf, Norman; Cassell, Ron; Johnson, Tony; McCormick, Jeremy; Magill, Steve; Kuhlmann, Steve

    2006-10-27

    At a future e+e- linear collider, precision measurements of jets will be required in order to understand physics at and beyond the electroweak scale. Calorimetry will be used with other detectors in an optimal way to reconstruct particle 4-vectors with unprecedented precision. This Particle Flow Algorithm (PFA) approach is seen as the best way to achieve particle mass resolutions from dijet measurements in the range of {approx}30%/{radical}E, resulting in innovative methods for choosing the calorimeter technology and optimizing the detector design.

  7. Intelligent Detector Design

    SciTech Connect

    Graf, N.; Cassell, R.; Johnson, T.; McCormick, J.; Magill, S.; Kuhlmann, S.; /Argonne

    2007-02-13

    At a future e+e- linear collider, precision measurements of jets will be required in order to understand physics at and beyond the electroweak scale. Calorimetry will be used with other detectors in an optimal way to reconstruct particle 4-vectors with unprecedented precision. This Particle Flow Algorithm (PFA) approach is seen as the best way to achieve particle mass resolutions from dijet measurements in the range of {approx} 30%/{radical}E, resulting in innovative methods for choosing the calorimeter technology and optimizing the detector design.

  8. Fission-fragment detector for DANCE based on thin scintillating films

    NASA Astrophysics Data System (ADS)

    Rusev, G.; Roman, A. R.; Daum, J. K.; Springs, R. K.; Bond, E. M.; Jandel, M.; Baramsai, B.; Bredeweg, T. A.; Couture, A.; Favalli, A.; Ianakiev, K. D.; Iliev, M. L.; Mosby, S.; Ullmann, J. L.; Walker, C. L.

    2015-12-01

    A fission-fragment detector based on thin scintillating films has been built to serve as a trigger/veto detector in neutron-induced fission measurements at DANCE. The fissile material is surrounded by scintillating films providing 4 ? detection of the fission fragments. The scintillation photons were registered with silicon photomultipliers. A measurement of the 235U (n, f) reaction with this detector at DANCE revealed a correct time-of-flight spectrum and provided an estimate for the efficiency of the prototype detector of 11.6(7)%. Design and test measurements with the detector are described.

  9. Matrix of integrated superconducting single-photon detectors with high timing resolution

    E-print Network

    Schuck, Carsten; Minaeva, Olga; Li, Mo; Gol'tsman, Gregory; Sergienko, Alexander V; Tang, Hong X

    2013-01-01

    We demonstrate a large grid of individually addressable superconducting single photon detectors on a single chip. Each detector element is fully integrated into an independent waveguide circuit with custom functionality at telecom wavelengths. High device density is achieved by fabricating the nanowire detectors in traveling wave geometry directly on top of silicon-on-insulator waveguides. Our superconducting single-photon detector matrix includes detector designs optimized for high detection efficiency, low dark count rate and high timing accuracy. As an example, we exploit the high timing resolution of a particularly short nanowire design to resolve individual photon round-trips in a cavity ring-down measurement of a silicon ring resonator.

  10. Fabrication of Pillar-Structured Thermal Neutron Detectors

    SciTech Connect

    Nikolic, R J; Conway, A M; Reinhardt, C E; Graff, R T; Wang, T F; Deo, N; Cheung, C L

    2007-11-19

    Pillar detector is an innovative solid state device structure that leverages advanced semiconductor fabrication technology to produce a device for thermal neutron detection. State-of-the-art thermal neutron detectors have shortcomings in achieving simultaneously high efficiency, low operating voltage while maintaining adequate fieldability performance. By using a 3-dimensional silicon PIN diode pillar array filled with isotopic boron 10, ({sup 10}B) a high efficiency device is theoretically possible. The fabricated pillar structures reported in this work are composed of 2 {micro}m diameter silicon pillars with a 4 {micro}m pitch and pillar heights of 6 and 12 {micro}m. The pillar detector with a 12 {micro}m height achieved a thermal neutron detection efficiency of 7.3% at 2V.

  11. The Upgraded D0 detector

    SciTech Connect

    Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, D.L.; Adams, M.; Adams, T.; Agelou, M.; Agram, J.-L.; Ahmed, S.N.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G.A.; Anastasoaie, M.; Andeen, T.; Anderson, J.T.; Anderson, S.; ,

    2005-07-01

    The D0 experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid-argon calorimeters and central muon detector, remaining from Run I, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to D0.

  12. The International Large Detector: Letter of Intent

    SciTech Connect

    Abe, Toshinori; Abernathy, Jason M.; Abramowicz, Halina; Adamus, Marek; Adeva, Bernardo; Afanaciev, Konstantin; Aguilar-Saavedra, Juan Antonio; Alabau Pons, Carmen; Albrecht, Hartwig; Andricek, Ladislav; Anduze, Marc; /Ecole Polytechnique /DESY

    2010-02-01

    The International Large Detector (ILD) is a concept for a detector at the International Linear Collider, ILC. The ILC will collide electrons and positrons at energies of initially 500 GeV, upgradeable to 1 TeV. The ILC has an ambitious physics program, which will extend and complement that of the Large Hadron Collider (LHC). The ILC physics case has been well documented, most recently in the ILC Reference Design Report, RDR. A hallmark of physics at the ILC is precision. The clean initial state and the comparatively benign environment of a lepton collider are ideally suited to high precision measurements. To take full advantage of the physics potential of ILC places great demands on the detector performance. The design of ILD, which is based on the GLD and the LDC detector concepts, is driven by these requirements. Excellent calorimetry and tracking are combined to obtain the best possible overall event reconstruction, including the capability to reconstruct individual particles within jets for particle flow calorimetry. This requires excellent spatial resolution for all detector systems. A highly granular calorimeter system is combined with a central tracker which stresses redundancy and efficiency. In addition, efficient reconstruction of secondary vertices and excellent momentum resolution for charged particles are essential for an ILC detector. The interaction region of the ILC is designed to host two detectors, which can be moved into the beam position with a 'push-pull' scheme. The mechanical design of ILD and the overall integration of subdetectors takes these operational conditions into account. The main features of ILD are outlined below. The central component of the ILD tracker is a Time Projection Chamber (TPC) which provides up to 224 precise measurements along the track of a charged particle. This is supplemented by a system of Silicon (Si) based tracking detectors, which provide additional measurement points inside and outside of the TPC, and extend the angular coverage down to very small angles. A Si-pixel based vertex detector (VTX) enables long lived particles such as b- and c-hadrons to be reconstructed. This combination of tracking devices, which has a large degree of redundancy, results in high track reconstruction efficiencies, and unprecedented momentum resolution and vertex reconstruction capabilities. One of the most direct measures of detector performance at the ILC is the jet-energy resolution. Precise di-jet mass reconstruction and separation of hadronically decaying W and Z bosons are essential for many physics channels. The ultimate jet energy resolution is achieved when every particle in the event, charged and neutral, is measured with the best possible precision. Within the paradigm of particle flow calorimetry, this goal is achieved by reconstructing charged particles in the tracker, photons in the electromagnetic calorimeter (ECAL), and neutral hadrons in the ECAL and hadronic calorimeter (HCAL). The ultimate performance is reached for perfect separation of charged-particle clusters from neutral particle clusters in the calorimeters. Thus, a highly granular calorimeter outside the tracker is the second key component of ILD. Sampling calorimeters with dense absorber material and fine grained readout are used. A tungsten absorber based electromagnetic calorimeter (ECAL) covers the first interaction length, followed by a somewhat coarser steel based sampling hadronic calorimeter (HCAL). Several ECAL and HCAL readout technologies are being pursued.

  13. Fast Detector Simulation Using Lelaps, Detector Descriptions in GODL

    SciTech Connect

    Langeveld, Willy; /SLAC

    2005-07-06

    Lelaps is a fast detector simulation program which reads StdHep generator files and produces SIO or LCIO output files. It swims particles through detectors taking into account magnetic fields, multiple scattering and dE/dx energy loss. It simulates parameterized showers in EM and hadronic calorimeters and supports gamma conversions and decays. In addition to three built-in detector configurations, detector descriptions can also be read from files in the new GODL file format.

  14. The CMS Beam Halo Monitor Detector System

    E-print Network

    Kelly Stifter; on behalf of the CMS Collaboration

    2015-11-01

    A new Beam Halo Monitor (BHM) detector system has been installed in the CMS cavern to measure the machine-induced background (MIB) from the LHC. This background originates from interactions of the LHC beam halo with the final set of collimators before the CMS experiment and from beam gas interactions. The BHM detector uses the directional nature of Cherenkov radiation and event timing to select particles coming from the direction of the beam and to suppress those originating from the interaction point. It consists of 40 quartz rods, placed on each side of the CMS detector, coupled to UV sensitive PMTs. For each bunch crossing the PMT signal is digitized by a charge integrating ASIC and the arrival time of the signal is recorded. The data are processed in real time to yield a precise measurement of per-bunch-crossing background rate. This measurement is made available to CMS and the LHC, to provide real-time feedback on the beam quality and to improve the efficiency of data taking. Here, I present the detector system and first results obtained in Run II.

  15. Atmospheric neutrinos observed in underground detectors

    NASA Technical Reports Server (NTRS)

    Gaisser, T. K.; Stanev, T.

    1985-01-01

    Atmospheric neutrinos are produced when the primary cosmic ray beam hits the atmosphere and initiates atmospheric cascades. Secondary mesons decay and give rise to neutrinos. The neutrino production was calculated and compared with the neutrino fluxes detected in underground detectors. Contained neutrino events are characterized by observation of an interaction within the fiducial volume of the detector when the incoming particle is not observed. Both the neutrino flux and the containment requirement restrict the energy of the neutrinos observed in contained interactions to less than several GeV. Neutrinos interact with the rock surrounding the detector but only muon neutrino interactions can be observed, as the electron energy is dissipated too fast in the rock. The direction of the neutrino is preserved in the interaction and at energies above 1 TeV the angular resolution is restricted by the scattering of the muon in the rock. The muon rate reflects the neutrino spectrum above some threshold energy, determined by the detector efficiency for muons.

  16. Optical detector calibrator system

    NASA Technical Reports Server (NTRS)

    Strobel, James P. (Inventor); Moerk, John S. (Inventor); Youngquist, Robert C. (Inventor)

    1996-01-01

    An optical detector calibrator system simulates a source of optical radiation to which a detector to be calibrated is responsive. A light source selected to emit radiation in a range of wavelengths corresponding to the spectral signature of the source is disposed within a housing containing a microprocessor for controlling the light source and other system elements. An adjustable iris and a multiple aperture filter wheel are provided for controlling the intensity of radiation emitted from the housing by the light source to adjust the simulated distance between the light source and the detector to be calibrated. The geared iris has an aperture whose size is adjustable by means of a first stepper motor controlled by the microprocessor. The multiple aperture filter wheel contains neutral density filters of different attenuation levels which are selectively positioned in the path of the emitted radiation by a second stepper motor that is also controlled by the microprocessor. An operator can select a number of detector tests including range, maximum and minimum sensitivity, and basic functionality. During the range test, the geared iris and filter wheel are repeatedly adjusted by the microprocessor as necessary to simulate an incrementally increasing simulated source distance. A light source calibration subsystem is incorporated in the system which insures that the intensity of the light source is maintained at a constant level over time.

  17. Directional gamma detector

    DOEpatents

    LeVert, Francis E. (Downers Grove, Knoxville, TN); Cox, Samson A. (Downers Grove, IL)

    1981-01-01

    An improved directional gamma radiation detector has a collector sandwiched etween two layers of insulation of varying thicknesses. The collector and insulation layers are contained within an evacuated casing, or emitter, which releases electrons upon exposure to gamma radiation. Delayed electrons and electrons entering the collector at oblique angles are attenuated as they pass through the insulation layers on route to the collector.

  18. Understanding the SNO+ Detector

    NASA Astrophysics Data System (ADS)

    Kamdin, K.

    SNO+, a large liquid scintillator experiment, is the successor of the Sudbury Neutrino Observatory (SNO) experiment. The scintillator volume will be loaded with large quantities of 130Te, an isotope that undergoes double beta decay, in order to search for neutrinoless double beta decay. In addition to this search, SNO+ has a broad physics program due to its sensitivity to solar and supernova neutrinos, as well as reactor and geo anti-neutrinos. SNO+ can also place competitive limits on certain modes of invisible nucleon decay during its first phase. The detector is currently undergoing commissioning in preparation for its first phase, in which the detector is filled with ultra pure water. This will be followed by a pure scintillator phase, and then a Tellurium-loaded scintillator phase to search for neutrinoless double beta decay. Here we present the work done to model detector aging, which was first observed during SNO. The aging was found to reduce the optical response of the detector. We also describe early results from electronics calibration of SNO+.

  19. The Friendship Detector

    ERIC Educational Resources Information Center

    Cox, Scott

    2012-01-01

    After years of using Rube Goldberg-inspired projects to teach concepts of simple machines, the author sought a comparable project to reinforce electricity lessons in his ninth-grade Science and Technology course. The Friendship Detector gives students a chance to design, test, and build a complex circuit with multiple switches and battery-powered…

  20. Sensitive hydrogen leak detector

    DOEpatents

    Myneni, G.R.

    1999-08-03

    A sensitive hydrogen leak detector system is described which uses passivation of a stainless steel vacuum chamber for low hydrogen outgassing, a high compression ratio vacuum system, a getter operating at 77.5 K and a residual gas analyzer as a quantitative hydrogen sensor. 1 fig.