TE INCLUSIONS AND THEIR RELATIONSHIP TO THE PERFORMANCE OF CDZNTE DETECTORS.

Energy Technology Data Exchange (ETDEWEB)

CARINI, G.A.; BOLOTNIKOV, A.E.; CAMARDA, G.S.; CUI, Y.; JACKSON, H.; BURGER, A.; KOHMAN, K.T.; LI, L.; JAMES, R.B.

2006-08-13

Te-rich secondary phases existing in CdZnTe (CZT) single crystals degrade the spectroscopic performance of these detectors. An unpredictable number of charges are trapped, corresponding to the abundance of these microscopic defects, thereby leading to fluctuations in the total collected charge and strongly affecting the uniformity of charge-collection efficiency. These effects, observed in thin planar detectors, also were found to be the dominant cause of the low performance of thick detectors, wherein the fluctuations accumulate along the charge's drift path. Reducing the size of Te inclusions from a virtual diameter of 10-20 {micro}m down to less than 5 {micro}m already allowed us to produce Frisch-ring detectors with a resolution as good as {approx}0.8% FWHM at 662 keV: Understanding and modeling the mechanisms involving Te-rich secondary phases and charge loss requires systematic studies on a spatial scale never before realized. Here, we describe a dedicated beam-line recently established at BNL's National Synchrotron Light Source for characterizing semiconductor detectors along with a IR system with counting capability that permits us to correlate the concentration of defects with the devices' performances.

High performance p-i-n CdTe and CdZnTe detectors

CERN Document Server

Khusainov, A K; Ilves, A G; Morozov, V F; Pustovoit, A K; Arlt, R D

1999-01-01

A breakthrough in the performance of p-i-n CdTe and CdZnTe detectors is reported. The detector stability has been significantly improved, allowing their use in precise gamma and XRF applications. Detectors with energy resolution close to Si and Ge were produced operating with only -30--35 deg. C cooling (by a Peltier cooler of 15x15x10 mm size and a consumed power less than 5 W). Presently detectors with volume of up to 300 mm sup 3 are available. In terms of photoelectric effect efficiency it corresponds to HPGe detectors with volumes of about 1.5 cm sup 3. The possibilities of further improvement of CdTe and CdZnTe detector characteristics are discussed in this paper.

Correction of diagnostic x-ray spectra measured with CdTe and CdZnTe detectors

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, M [Osaka Univ., Suita (Japan). Medical School; Kanamori, H; Toragaito, T; Taniguchi, A

1996-07-01

We modified the formula of stripping procedure presented by E. Di. Castor et al. We added the Compton scattering and separated K{sub {alpha}} radiation of Cd and Te (23 and 27keV, respectively). Using the new stripping procedure diagnostic x-ray spectra (object 4mm-Al) of tube voltage 50kV to 100kV for CdTe and CdZnTe detectors are corrected with comparison of those spectra for the Ge detector. The corrected spectra for CdTe and CdZnTe detectors coincide with those for Ge detector at lower tube voltage than 70kV. But the corrected spectra at higher tube voltage than 70kV do not coincide with those for Ge detector. The reason is incomplete correction for full energy peak efficiencies of real CdTe and CdZnTe detectors. (J.P.N.)

Infrared LED Enhanced Spectroscopic CdZnTe Detector Working under High Fluxes of X-rays

Directory of Open Access Journals (Sweden)

Jakub Pekárek

2016-09-01

Full Text Available This paper describes an application of infrared light-induced de-polarization applied on a polarized CdZnTe detector working under high radiation fluxes. We newly demonstrate the influence of a high flux of X-rays and simultaneous 1200-nm LED illumination on the spectroscopic properties of a CdZnTe detector. CdZnTe detectors operating under high radiation fluxes usually suffer from the polarization effect, which occurs due to a screening of the internal electric field by a positive space charge caused by photogenerated holes trapped at a deep level. Polarization results in the degradation of detector charge collection efficiency. We studied the spectroscopic behavior of CdZnTe under various X-ray fluxes ranging between 5 × 10 5 and 8 × 10 6 photons per mm 2 per second. It was observed that polarization occurs at an X-ray flux higher than 3 × 10 6 mm − 2 ·s − 1 . Using simultaneous illumination of the detector by a de-polarizing LED at 1200 nm, it was possible to recover X-ray spectra originally deformed by the polarization effect.

Surface Passivation of CdZnTe Detector by Hydrogen Peroxide Solution Etching

Science.gov (United States)

Hayes, M.; Chen, H.; Chattopadhyay, K.; Burger, A.; James, R. B.

1998-01-01

The spectral resolution of room temperature nuclear radiation detectors such as CdZnTe is usually limited by the presence of conducting surface species that increase the surface leakage current. Studies have shown that the leakage current can be reduced by proper surface preparation. In this study, we try to optimize the performance of CdZnTe detector by etching the detector with hydrogen peroxide solution as function of concentration and etching time. The passivation effect that hydrogen peroxide introduces have been investigated by current-voltage (I-V) measurement on both parallel strips and metal-semiconductor-metal configurations. The improvements on the spectral response of Fe-55 and 241Am due to hydrogen peroxide treatment are presented and discussed.

Control of electric field in CdZnTe radiation detectors by above-bandgap light

International Nuclear Information System (INIS)

Franc, J.; Dědič, V.; Rejhon, M.; Zázvorka, J.; Praus, P.; Touš, J.; Sellin, P. J.

2015-01-01

We have studied the possibility of above bandgap light induced depolarization of CdZnTe planar radiation detector operating under high flux of X-rays by Pockels effect measurements. In this contribution, we show a similar influence of X-rays at 80 kVp and LED with a wavelength of 910 nm irradiating the cathode on polarization of the detector due to an accumulation of a positive space charge of trapped photo-generated holes. We have observed the depolarization of the detector under simultaneous cathode-site illumination with excitation LED at 910 nm and depolarization above bandgap LED at 640 nm caused by trapping of drifting photo-generated electrons. Although the detector current is quite high during this depolarization, we have observed that it decreases relatively fast to its initial value after switching off the depolarizing light. In order to get detailed information about physical processes present during polarization and depolarization and, moreover, about associated deep levels, we have performed the Pockels effect infrared spectral scanning measurements of the detector without illumination and under illumination in polarized and optically depolarized states

Control of electric field in CdZnTe radiation detectors by above-bandgap light

Energy Technology Data Exchange (ETDEWEB)

Franc, J.; Dědič, V.; Rejhon, M.; Zázvorka, J.; Praus, P. [Institute of Physics of Charles University, Prague (Czech Republic); Touš, J. [Crytur Ltd., Turnov (Czech Republic); Sellin, P. J. [Department of Physics, University of Surrey, Guildford (United Kingdom)

2015-04-28

We have studied the possibility of above bandgap light induced depolarization of CdZnTe planar radiation detector operating under high flux of X-rays by Pockels effect measurements. In this contribution, we show a similar influence of X-rays at 80 kVp and LED with a wavelength of 910 nm irradiating the cathode on polarization of the detector due to an accumulation of a positive space charge of trapped photo-generated holes. We have observed the depolarization of the detector under simultaneous cathode-site illumination with excitation LED at 910 nm and depolarization above bandgap LED at 640 nm caused by trapping of drifting photo-generated electrons. Although the detector current is quite high during this depolarization, we have observed that it decreases relatively fast to its initial value after switching off the depolarizing light. In order to get detailed information about physical processes present during polarization and depolarization and, moreover, about associated deep levels, we have performed the Pockels effect infrared spectral scanning measurements of the detector without illumination and under illumination in polarized and optically depolarized states.

Gas filled prototype of a CdZnTe pixel detector

International Nuclear Information System (INIS)

Ramsey, B.; Sharma, D.; Sipila, H.; Gostilo, V.; Loupilov, A.

2001-01-01

CdZnTe pixel structures are currently the most promising detectors for the focal planes of hard X-ray telescopes, for astronomical observation in the range 5-100 keV. In Sharma et al. (Proc. SPIE 3765 (1999) 822) and Ramsey et al. (Nucl. Instrum. Methods A 458 (2001) 55) we presented preliminary results on the development of prototype 4x4 CdZnTe imaging detectors operated under vacuum. These pixel detectors were installed inside vacuum chambers on three-stage Peltier coolers providing detector temperatures down to -40 deg. C. A miniature sputter ion pump inside each chamber maintained the necessary vacuum of 10 -5 Torr. At a temperature of -20 deg. C we achieved an FWHM energy resolution of between 2% and 3% at 60 keV and ∼15% at 5.9 keV; however, the dependency on temperature was weak and at +20 deg. C the respective resolutions were 3% and 20%. As the detectors could be operated at room temperature without loss of their good characteristics it was possible to exclude the sputter ion pump and fill the chamber with dry nitrogen instead. We have tested a nitrogen-filled CdZnTe (5x5x1 mm 3 ) prototype having 0.65x0.65 mm 2 readout pads on a 0.75 mm pitch. The interpixel resistance at an applied voltage of 10 V was higher than 50 GΩ and the pixel leakage currents at room temperature with a bias of 200 V between each pad and the common electrode did not exceed 0.8 nA. The pixel detector inside the microassembly, which also contained the input stages of the preamplifiers, was installed on a Peltier cooler to maintain the detector temperature at +20 deg. C. To define real leakage currents of the pixels in their switched-on state we have checked the voltage on the preamplifiers feedback resistors. The resulting currents were 10-50 pA at a detector bias of 500 V. Under test, the typical energy resolution per pixel at +20 deg. C was ∼3% at energy 59.6 keV and ∼20% at energy 5.9 keV, which are similar to the values obtained in the vacuum prototype at room temperature

Noise in CdZnTe detectors

International Nuclear Information System (INIS)

Luke, P. N.; Amman, M.; Lee, J. S.; Manfredi, P. F.

2000-01-01

Noise in CdZnTe devices with different electrode configurations was investigated. Measurements on devices with guard-ring electrode structures showed that surface leakage current does not produce any significant noise. The parallel white noise component of the devices appeared to be generated by the bulk current alone, even though the surface current was substantially higher. This implies that reducing the surface leakage current of a CdZnTe detector may not necessarily result in a significant improvement in noise performance. The noise generated by the bulk current is also observed to be below full shot noise. This partial suppression of shot noise may be the result of Coulomb interaction between carriers or carrier trapping. Devices with coplanar strip electrodes were observed to produce a 1/f noise term at the preamplifier output. Higher levels of this 1/f noise were observed with decreasing gap widths between electrodes. The level of this 1/f noise appeared to be independent of bias voltage and leakage current but was substantially reduced after certain surface treatments

Study on the mechanism of using IR illumination to improve the carrier transport performance of CdZnTe detector

Science.gov (United States)

Mao, Yifei; Zhang, Jijun; Lin, Liwen; Lai, Jianming; Min, Jiahua; Liang, Xiaoyan; Huang, Jian; Tang, Ke; Wang, Linjun

2018-04-01

Different wavelength IR light (770-1150 nm) was used to evaluate the effect of IR light on the carrier transport performance of CdZnTe detector. The effective mobility-lifetime product (μτ*) of CdZnTe achieved 10-2 cm2 V-1 when the IR wavelength was in the range of 820-920 nm, but decreased to 1 × 10-4 cm2 V-1 when the wavelength was longer than 920 nm. The mechanism about how IR light affecting the carrier transport property of CdZnTe detector was analyzed with Shockley-Read-Hall model. The defect of doubly ionized Cd vacancy ([VCd]2-) was found to be the main factor that assist IR light affecting the μτ of CdZnTe detector. The photoconductive experiment under 770-1150 nm IR illumination was carried out, and three kinds of photocurrent curve were detected and analyzed by solving the Hecht equation. The experiments demonstrated the effect of [VCd]2- defect on the carrier transport property of CdZnTe detector under IR illumination.

Primary study of Monte Carlo simulation on CdZnTe nuclear detector

International Nuclear Information System (INIS)

Ren Shaojun; Sang Wenbin; Jin Wei; Li Wanwan; Zhang Qi; Min Jiahua

2004-01-01

The Monte Carlo simulation software is developed based on the operating principle of CdZnTe detector, the randomicity of γ ray reaction in the detector and the statistic rule of the amount of electron-hole pairs produced. First, the reaction depth of photons is calculated based on the disintegration rule. Secondly, the reaction section of every reaction is estimated and the reaction probability of the three atoms in CZT and the probability of every reaction of every atom are calculated. Based on these probabilities, the category of atoms and the type of reactions of a photon reacting with the detector are determined and the amount of electron-hole pairs produced by the photon is obtained. From the reaction depth and the amount of electron-hole pairs produced, the amount of charge collected can be calculated. The response energy spectra of γ ray in the CdZnTe detector are simulated by using the Monte Carlo software developed. The simulation results are well comparable with the data of the real CdZnTe devices. In addition, the ideal thickness of the device, which is of maximum detecting efficiency, is also obtained based on the analysis over the relationship between the thickness and the efficiency, assuming the device to be under the radiation of 57 Co source

Internal electric-field-lines distribution in CdZnTe detectors measured using X-ray mapping

International Nuclear Information System (INIS)

Bolotnikov, A.E.; Camarda, G.S.; Cui, Y.; Hossain, A.; Yang, G.; Yao, H.W.; James, R.B.

2009-01-01

The ideal operation of CdZnTe devices entails having a uniformly distributed internal electric field. Such uniformity especially is critical for thick long-drift-length detectors, such as large-volume CPG and 3-D multi-pixel devices. Using a high-spatial resolution X-ray mapping technique, we investigated the distribution of the electric field in real devices. Our measurements demonstrate that in thin detectors, 1 cm, with a large aspect ratio (thickness-to-width ratio), we observed two effects: the electric field lines bending away from or towards the side surfaces, which we called, respectively, the focusing field-line distribution and the defocusing field-line distribution. In addition to these large-scale variations, the field-line distributions were locally perturbed by the presence of extended defects and residual strains existing inside the crystals. We present our data clearly demonstrating the non-uniformity of the internal electric field

Prototype of the stacked CdZnTe semiconductor detector for 16N measurement

International Nuclear Information System (INIS)

Nishizawa, Hiroshi; Inujima, Hiroshi; Fujiwara, Hirotsugu; Nakamura, Hiroaki

2001-01-01

Prototype of the Stacked CdZnTe Semiconductor Detector for Measurement The prototype model of the stacked CdZnTe semiconductor detector, which is able to measure the 6.13 MeV γ-ray from 16 N, was fabricated. The prototype's response calculation was carried out by Monte-Carlo method. The result of the response calculation agreed with the experiment data of check sources of 137 Cs and 60 Co, and 16 N which was measured at vicinity of the primary cooling water pipe of the nuclear reactor. The source spectra were unfolded with detector's response function obtained by simulation, and it is indicated that the incident γ-ray energy and its intensity ratio was identified and that the energy of 6 MeV γ-ray could be measured by the prototype of the stacked detector. (author)

A CdZnTe slot-scanned detector for digital mammography

International Nuclear Information System (INIS)

Mainprize, James G.; Ford, Nancy L.; Yin Shi; Gordon, Eli E.; Hamilton, William J.; Tuemer, Tuemay O.; Yaffe, Martin J.

2002-01-01

A new high-resolution detector has been developed for use in a slot-scanned digital mammography system. The detector is a hybrid device that consists of a CCD operating in time-delay integration mode that is bonded to a 150-μm-thick CdZnTe photoconductor array. The CCD was designed with a detector element pitch of 50 μm. Two devices were evaluated with differing crystalline quality. Incomplete charge collection was a source of reduction in DQE. This occurs in both devices due to characteristically low mobility-lifetime products for CdZnTe, with the greatest losses demonstrated by the multicrystalline sample. The mobility-lifetime products for the multicrystalline device were found to be 2.4x10 -4 and 4.0x10 -7 cm 2 /V for electrons and holes, respectively. The device constructed with higher quality single crystal CdZnTe demonstrated mobility-lifetime products of 1.0x10 -4 and 4.4x10 -6 cm 2 /V for electrons and holes. The MTF and DQE for the device were measured at several exposures and results were compared to predictions from a linear systems model of signal and noise propagation. The MTF at a spatial frequency of 10 mm -1 exceeded 0.18 and 0.56 along the scan and slot directions, respectively. Scanning motion and CCD design limited the resolution along the scan direction. For an x-ray beam from a tungsten target tube with 40 μm molybdenum filtration operated at 26 kV, the single crystal device demonstrated a DQE(0) of 0.70±0.02 at 7.1x10 -6 C/kg (27 mR) exposure to the detector, despite its relatively poor charge collection efficiency

Influence of infrared stimulation on spectroscopy characteristics of co-planar grid CdZnTe detectors

International Nuclear Information System (INIS)

Fjodorov, V.; Ivanov, V.; Loutchanski, A.

2015-01-01

It was previously found that illumination with monochromatic infrared (IR) light with wavelengths close to the absorption edge of the CdZnTe exert significant positive influence on the spectrometric characteristics of quasi-hemispherical CdZnTe detectors at room temperature. In this paper, preliminary results of IR stimulation on the spectrometric characteristics of coplanar-grid CdZnTe detectors as well as results of further studies of planar and quasi-hemispherical detectors are presented. Coplanar-grid detectors of 10 mm x 10 mm x 10 mm from Redlen Technologies and commercial available IR LEDs with different wavelengths of 800-1000 nm were used in the experiments. Influence of intensity and direction of IR illumination on the detector's characteristics was studied. Analysis of signals shapes from the preamplifiers outputs at registration of alpha particles showed that IR illumination leads to a change in the shapes of these signals. This may indicate changes in electric fields distributions. An improvement in energy resolution at gamma-energy of 662 keV was observed with quasi-hemispherical and co-planar detectors at the certain levels of IR illumination intensity. The most noticeable effect of IR stimulation was observed with quasi-hemispherical detectors. It is due with optimization of charge collection conditions in the quasi-hemispherical detectors under IT stimulation. (authors)

Leakage current measurements on pixelated CdZnTe detectors

International Nuclear Information System (INIS)

Dirks, B.P.F.; Blondel, C.; Daly, F.; Gevin, O.; Limousin, O.; Lugiez, F.

2006-01-01

In the field of the R and D of a new generation hard X-ray cameras for space applications we focus on the use of pixelated CdTe or CdZnTe semiconductor detectors. They are covered with 64 (0.9x0.9 mm 2 ) or 256 (0.5x0.5 mm 2 ) pixels, surrounded by a guard ring and operate in the energy ranging from several keV to 1 MeV, at temperatures between -20 and +20 o C. A critical parameter in the characterisation of these detectors is the leakage current per pixel under polarisation (∼50-500 V/mm). In operation mode each pixel will be read-out by an integrated spectroscopy channel of the multi-channel IDeF-X ASIC currently developed in our lab. The design and functionality of the ASIC depends directly on the direction and value of the current. A dedicated and highly insulating electronics circuit is designed to automatically measure the current in each individual pixel, which is in the order of tens of pico-amperes. Leakage current maps of different CdZnTe detectors of 2 and 6 mm thick and at various temperatures are presented and discussed. Defect density diagnostics have been performed by calculation of the activation energy of the material

Coplanar-grid CdZnTe detector with three-dimensional position sensitivity

International Nuclear Information System (INIS)

Luke, P.N.; Amman, M.; Lee, J.S.; Yaver, H.

1998-06-01

A 3-dimensional position-sensitive coplanar-grid detector design for use with compound semiconductors is described. This detector design maintains the advantage of a coplanar-grid detector in which good energy resolution can be obtained from materials with poor charge transport. Position readout in two dimensions is accomplished using proximity-sensing electrodes adjacent to the electron-collecting grid electrode of the detector. Additionally, depth information is obtained by taking the ratio of the amplitudes of the collecting grid signal and the cathode signal. Experimental results from a prototype CdZnTe detector are presented

CdTe and CdZnTe gamma ray detectors for medical and industrial imaging systems

International Nuclear Information System (INIS)

Eisen, Y.; Shor, A.; Mardor, I.

1999-01-01

CdTe and CdZnTe X-ray and gamma ray detectors in the form of single elements or as segmented monolithic detectors have been shown to be useful in medical and industrial imaging systems. These detectors possess inherently better energy resolution than scintillators coupled to either photodiodes or photomultipliers, and together with application specific integrated circuits they lead to compact imaging systems of enhanced spatial resolution and better contrast resolution. Photopeak efficiencies of these detectors is greatly affected by a relatively low hole mobility-lifetime product. Utilizing these detectors as highly efficient good spectrometers, demands use of techniques to improve their charge collection properties, i.e., correct for variations in charge losses at different depths of interaction in the detector. The corrections for the large hole trapping are made either by applying electronic techniques or by fabricating detector or electrical contacts configurations which differ from the commonly used planar detectors. The following review paper is divided into three parts: The first part discusses detector contact configurations for enhancing photopeak efficiencies and the single carrier collection approach which leads to improved energy resolutions and photopeak efficiencies at high gamma ray energies. The second part demonstrates excellent spectroscopic results using thick CdZnTe segmented monolithic pad and strip detectors showing energy resolutions less than 2% FWHM at 356 keV gamma rays. The third part discusses advantages and disadvantages of CdTe and CdZnTe detectors in imaging systems and describes new developments for medical diagnostics imaging systems

Spiral silicon drift detectors

International Nuclear Information System (INIS)

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

Drift chamber detectors

International Nuclear Information System (INIS)

Duran, I.; Martinez Laso, L.

1989-01-01

A review of High Energy Physics detectors based on drift chambers is presented. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysied, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author)

Characterization of large volume CdZnTe detectors with a quad-grid structure for the COBRA experiment

Energy Technology Data Exchange (ETDEWEB)

Rohatsch, Katja [TU Dresden, Institut fuer Kern- und Teilchenphysik, 01069 Dresden (Germany); Collaboration: COBRA-Collaboration

2016-07-01

The COBRA experiment uses room temperature semiconductor detectors made of Cadmium-Zinc-Telluride, which contains several double beta isotopes, to search for neutrinoless double beta-decay. To compensate for poor hole transport in CdZnTe the detectors are equipped with a coplanar grid (CPG) instead of a planar anode. Currently, a demonstrator setup consisting of 64 1 cm{sup 3} CPG-detectors is in operation at the LNGS in Italy to prove the concept and to determine the long-term stability of the detectors and the instrumentation. For a future large scale experiment it is planned to use larger CdZnTe detectors with a volume of 6 cm{sup 3}, because of the better surface-to-volume ratio and the higher full energy detection efficiency. This will also reduce the background contribution of surface contaminations. Before the installation at the LNGS the new detector design is validated and studied in detail. This talk presents a laboratory experiment for the characterization with γ-radiation of 6 cm{sup 3} CdZnTe quad-grid detectors. The anode of such a detector is divided into four sub-CPGs. The characterization routine consists of the determination of the optimal working point and two-dimensional spatially resolved scans with a highly collimated γ-source.

Current state-of-the-art industrial and research applications using room-temperature CdTe and CdZnTe solid state detectors

International Nuclear Information System (INIS)

Eisen, Y.

1996-01-01

Improvements of CdTe crystal quality and significant progress in the growth of large ingots of high resistivity CdZnTe material enable the fabrication of larger area detectors in single element form or monolithic arrays. These advances allow for the development of imaging devices of improved spatial resolution for industrial, research and medical applications. CdTe and CdZnTe detectors operate in single photon counting mode or in current mode (charge integrating mode). The paper presents advantages of CdTe and CdZnTe over common scintillator type detectors, but also presents the shortcomings of the former detectors with respect to charge collection which limit the yields of good spectrometers. The paper reviews industrial and research applications utilizing these detectors and in particular describes in detail two imaging systems for security screening and custom inspection. These systems are characterized by large dynamic range and good spatial resolution and are composed of large arrays of CdTe spectrometers and discriminator grade detectors. A wide energy range detector assembly, for astrophysical research of gamma ray bursts composed of CdTe, HgI 2 and CdZnTe spectrometers in two dimensional arrays is also presented. (orig.)

Drift Chambers detectors

International Nuclear Information System (INIS)

Duran, I.; Martinez laso, L.

1989-01-01

We present here a review of High Energy Physics detectors based on drift chambers. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysed, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author) 115 refs

Evaluation the image obtained from X-ray flat-panel detectors utilizing a polycrystalline CdZnTe film as the conversion layer

International Nuclear Information System (INIS)

Tokuda, S.; Kishihara, H.; Kaino, M.; Sato, T.

2006-01-01

We can expect that fluoroscopic images with a high sensitivity and excellent detective efficiency can be obtained by using a semiconductor with a small W factor for the conversion layer of X-ray flat-panel detectors, which have experienced a rapid gain inpopularity for medical and non-destructive industrial inspection uses in recent years. We believe that polycrystalline CdZnTe film formed by the closed spaced sublimation (CSS) method is a promising conversion material for next-generation high efficiency X-ray flat-panel detectors, and have previously reported the results of feasibility studies. In this paper, we present an overview of X-ray flat-panel detectors and the features of CdZnTe film, then we describe the CSS method of deposition and evaluation of the physical characteristics of CdZnTe film, and finally we present the results of our fabrication and testing of proto-type detectors utilizing CdZnTe film. (author)

Leakage current measurements on pixelated CdZnTe detectors

NARCIS (Netherlands)

Dirks, B.; Blondel, C.; Daly, F.; Gevin, O.; Limousin, O.; Lugiez, F.

2006-01-01

In the field of the R&D of a new generation hard X-ray cameras for space applications we focus on the use of pixelated CdTe or CdZnTe semiconductor detectors. They are covered with 64 (0.9×0.9 mm2) or 256 (0.5×0.5 mm2) pixels, surrounded by a guard ring and operate in the energy ranging from several

CdTe and CdZnTe detectors behavior in X-ray computed tomography conditions

CERN Document Server

Ricq, S; Garcin, M

2000-01-01

The application of CdTe and CdZnTe 2D array detectors for medical X-ray Computed Tomography (XCT) is investigated. Different metallic electrodes have been deposited on High-Pressure Bridgman Method CdZnTe and on Traveling Heater Method CdTe:Cl. These detectors are exposed to X-rays in the CT irradiation conditions and are characterized experimentally in current mode. Detectors performances such as sensitivity and response speed are studied. They are correlated with charge trapping and de-trapping. The trapped carrier space charges may influence the injection from the electrodes. This enables one to get information on the nature of the predominant levels involved. The performances achieved are encouraging: dynamic ranges higher than 4 decades and current decreases of 3 decades in 4 ms after X-ray beam cut-off are obtained. Nevertheless, these detectors are still limited by high trap densities responsible for the memory effect that makes them unsuitable for XCT.

Drift Chambers detectors; Detectores de deriva

Energy Technology Data Exchange (ETDEWEB)

Duran, I; Martinez laso, L

1989-07-01

We present here a review of High Energy Physics detectors based on drift chambers. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysed, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author) 115 refs.

Performance comparison of small-pixel CdZnTe radiation detectors with gold contacts formed by sputter and electroless deposition

Science.gov (United States)

Bell, S. J.; Baker, M. A.; Duarte, D. D.; Schneider, A.; Seller, P.; Sellin, P. J.; Veale, M. C.; Wilson, M. D.

2017-06-01

Recent improvements in the growth of wide-bandgap semiconductors, such as cadmium zinc telluride (CdZnTe or CZT), has enabled spectroscopic X/γ-ray imaging detectors to be developed. These detectors have applications covering homeland security, industrial analysis, space science and medical imaging. At the Rutherford Appleton Laboratory (RAL) a promising range of spectroscopic, position sensitive, small-pixel Cd(Zn)Te detectors have been developed. The challenge now is to improve the quality of metal contacts on CdZnTe in order to meet the demanding energy and spatial resolution requirements of these applications. The choice of metal deposition method and fabrication process are of fundamental importance. Presented is a comparison of two CdZnTe detectors with contacts formed by sputter and electroless deposition. The detectors were fabricated with a 74 × 74 array of 200 μm pixels on a 250 μm pitch and bump-bonded to the HEXITEC ASIC. The X/γ-ray emissions from an 241Am source were measured to form energy spectra for comparison. It was found that the detector with contacts formed by electroless deposition produced the best uniformity and energy resolution; the best pixel produced a FWHM of 560 eV at 59.54 keV and 50% of pixels produced a FWHM better than 1.7 keV . This compared with a FWHM of 1.5 keV for the best pixel and 50% of pixels better than 4.4 keV for the detector with sputtered contacts.

Investigation of the limitations of the highly pixilated CdZnTe detector for PET applications.

Science.gov (United States)

Komarov, Sergey; Yin, Yongzhi; Wu, Heyu; Wen, Jie; Krawczynski, Henric; Meng, Ling-Jian; Tai, Yuan-Chuan

2012-11-21

We are investigating the feasibility of a high resolution positron emission tomography (PET) insert device based on the CdZnTe detector with 350 µm anode pixel pitch to be integrated into a conventional animal PET scanner to improve its image resolution. In this paper, we have used a simplified version of the multi pixel CdZnTe planar detector, 5 mm thick with 9 anode pixels only. This simplified 9 anode pixel structure makes it possible to carry out experiments without a complete application-specific integrated circuits readout system that is still under development. Special attention was paid to the double pixel (or charge sharing) detections. The following characteristics were obtained in experiment: energy resolution full-width-at-half-maximum (FWHM) is 7% for single pixel and 9% for double pixel photoelectric detections of 511 keV gammas; timing resolution (FWHM) from the anode signals is 30 ns for single pixel and 35 ns for double pixel detections (for photoelectric interactions only the corresponding values are 20 and 25 ns); position resolution is 350 µm in x,y-plane and ∼0.4 mm in depth-of-interaction. The experimental measurements were accompanied by Monte Carlo (MC) simulations to find a limitation imposed by spatial charge distribution. Results from MC simulations suggest the limitation of the intrinsic spatial resolution of the CdZnTe detector for 511 keV photoelectric interactions is 170 µm. The interpixel interpolation cannot recover the resolution beyond the limit mentioned above for photoelectric interactions. However, it is possible to achieve higher spatial resolution using interpolation for Compton scattered events. Energy and timing resolution of the proposed 350 µm anode pixel pitch detector is no better than 0.6% FWHM at 511 keV, and 2 ns FWHM, respectively. These MC results should be used as a guide to understand the performance limits of the pixelated CdZnTe detector due to the underlying detection processes, with the understanding of

Cooled CdZnTe detectors for X-ray astronomy

CERN Document Server

Bale, G; Seller, P; Lowe, B

1999-01-01

Recent results combining thermoelectrically cooled CdZnTe detectors with a low-noise Pentafet preamplifier are presented. Cooling between -30 deg. C and -40 deg. C reduces the leakage current of the detectors and allows the use of a pulsed reset preamplifier and long shaping times, significantly improving the energy resolution. Mn K subalpha X-rays at 5.9 keV have been observed with a resolution of less than 280 eV FWHM and a peak to background of more than 200:1. The Fano factor of the material has been estimated at 0.11+-0.012 at -40 deg. C. The detector requirement for X-ray astronomy will be a photon-counting imaging spectrometer. A 16x16 element, bump bonded pixel detector is described and results from a prototype silicon array presented. The detector is constructed with ASIC amplifiers with a system noise of <25 electrons rms and should give an energy resolution comparable to the Pentafet results presented here.

Measurement of the drift mobilities and the mobility-lifetime products of charge carriers in a CdZnTe crystal by using a transient pulse technique

International Nuclear Information System (INIS)

Cho, H Y; Kwon, Y K; Lee, C S; Lee, J H; Moon, J Y

2011-01-01

In this work we present results on the measurement of the drift mobility and the mobility-lifetime product of charge carriers in a 16-pixellated CdZnTe detector. For the determination of an interaction position based on the pulse rise-time method in a CZT detector, it is necessary to characterize the transport properties governed by drift mobility and lifetime for electrons and holes. In order to extract the transport properties of an electron and a hole, we bombarded 5.5-MeV alpha particles from a 241 Am source and 81-keV gamma rays emitted from a 133 Ba source on the negatively biased contact of the CZT detector. A time-of-flight (TOF) method was used to measure the electron drift mobility at room temperature whose value turned out to be 906.4 cm 2 /Vc s. With the Hecht's equation, the electron mobility-lifetime product was also determined from the bias-dependent alpha response and was equal to (9.88 ± 2.33) x 10 -3 cm 2 /V. On the other hand, the hole mobility-lifetime product was evaluated by a model based on the average charge collection efficiency which accounts for the absorption probability with a given photon energy. By using a single parameter fitting of the model, we obtained the hole mobility-lifetime product of (8.28 ± 0.17) x 10 -4 cm 2 /V.

Development of CdZnTe X-ray detectors at DSRI

DEFF Research Database (Denmark)

van Pamelen, M.A.J.; Budtz-Jørgensen, Carl; Kuvvetli, Irfan

2000-01-01

An overview of the development of CdZnTe X-ray detectors at the Danish Space Research Institute is presented. Initiated in the beginning of 1996, the main motivation at that time was to develop focal plane detectors for the novel type of hard X-ray telescopes, which are currently under study...... developed a technique, which, with the use of microstrip electrodes, is able to compensate for the signal loss caused by trapping of positive charge carriers. This technique leads to a dramatic improvement of the achievable energy resolution, even for crystals of poor quality. With the technique, hole...

Diagnostic X-ray spectrometry using a commercial CdZnTe detector

International Nuclear Information System (INIS)

Becker, P.H.B.

1998-01-01

X ray spectrometry using Ge or Si detectors is an established tool to measure characterization parameters of X-ray beams. This work describes how a commercial CdZnTe was used to perform diagnostic X-ray spectrometry. Spectra were measured for two X-ray machines and compared with similar data found in the literature with an agreement of 2% rms

Progress in semiconductor drift detectors

International Nuclear Information System (INIS)

Rehak, P.; Walton, J.; Gatti, E.

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

Discrimination of alpha particles in CdZnTe detectors with coplanar grid for the COBRA experiment

Energy Technology Data Exchange (ETDEWEB)

Rebber, Henning [Universitaet Hamburg, Institut fuer Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg (Germany); Collaboration: COBRA-Collaboration

2016-07-01

The aim of the COBRA experiment is the search for neutrinoless double beta decay using CdZnTe semiconductor detectors. A background rate in the order of 10{sup -3} counts per keV, kg and year is intended in order to be sensitive to a half-life larger than 10{sup 26} years. Measurements from a demonstrator setup and Monte Carlo simulations indicate that a large background component is due to alpha particles. These generate charge clouds of only few μm in diameter in the detector, leading to characteristic pulse features. Parameter-based cut criteria were developed to discriminate alpha events by means of their pulse shapes. The cuts were tested on data from alpha and beta irradiation of a (1 x 1 x 1) cm{sup 3} CdZnTe detector with coplanar grid. The pulse shapes of all event signals were read out by FADCs with a sampling rate of 100 MHz. The signals were reproduced by a detector simulation which hence was used to study the cuts for energies up to 3 MeV and different detector regions.

Fluctuations in induced charge introduced by Te inclusions within CdZnTe radiation detectors

International Nuclear Information System (INIS)

Bale, Derek S.

2010-01-01

Recently, homogenization theory based on a multiple-scale perturbation of the electron transport equation has been used to derive a mathematical framework for modeling the excess charge lost to Te inclusions within radiation detectors based on semi-insulating cadmium zinc telluride (CdZnTe). In that theory, the heterogeneous material is mathematically replaced by a homogenized CdZnTe crystal whose effective electron attenuation length incorporates the additional uniform electron trapping caused by the inclusions. In this paper, the homogenization theory is extended to incorporate fluctuations in the induced charge (i.e., charge collection nonuniformities) introduced by the random position and size distributions of a noncorrelated population of small (i.e, <20 μm) Te inclusions. Analysis of the effective parameters derived within the homogenized framework is used to develop a probability distribution of effective electron attenuation lengths, and therefore effective mobility-lifetime products, as a function of both the position and size distribution of Te inclusions. Example distributions are detailed for the case of an exponential size distribution at various number densities. Further, it is demonstrated that the inclusion-induced material nonuniformities derived in this paper can be numerically sampled efficiently, making them applicable to Monte Carlo device simulation of realistic CdZnTe detectors. Simulated charge induction maps and pulse-height spectra are presented and compared to recently published measurements.

Pulse shaping system research of CdZnTe radiation detector for high energy x-ray diagnostic

Science.gov (United States)

Li, Miao; Zhao, Mingkun; Ding, Keyu; Zhou, Shousen; Zhou, Benjie

2018-02-01

As one of the typical wide band-gap semiconductor materials, the CdZnTe material has high detection efficiency and excellent energy resolution for the hard X-ray and the Gamma ray. The generated signal of the CdZnTe detector needs to be transformed to the pseudo-Gaussian pulse with a small impulse-width to remove noise and improve the energy resolution by the following nuclear spectrometry data acquisition system. In this paper, the multi-stage pseudo-Gaussian shaping-filter has been investigated based on the nuclear electronic principle. The optimized circuit parameters were also obtained based on the analysis of the characteristics of the pseudo-Gaussian shaping-filter in our following simulations. Based on the simulation results, the falling-time of the output pulse was decreased and faster response time can be obtained with decreasing shaping-time τs-k. And the undershoot was also removed when the ratio of input resistors was set to 1 to 2.5. Moreover, a two stage sallen-key Gaussian shaping-filter was designed and fabricated by using a low-noise voltage feedback operation amplifier LMH6628. A detection experiment platform had been built by using the precise pulse generator CAKE831 as the imitated radiation pulse which was equivalent signal of the semiconductor CdZnTe detector. Experiment results show that the output pulse of the two stage pseudo-Gaussian shaping filter has minimum 200ns pulse width (FWHM), and the output pulse of each stage was well consistent with the simulation results. Based on the performance in our experiment, this multi-stage pseudo-Gaussian shaping-filter can reduce the event-lost caused by pile-up in the CdZnTe semiconductor detector and improve the energy resolution effectively.

Performance of CdZnTe strip detectors as sub-millimeter resolution imaging gamma radiation spectrometers

International Nuclear Information System (INIS)

Mayer, M.; Boykin, D.V.; Drake, A.

1996-01-01

We report γ-ray detection performance measurements and computer simulations of a sub-millimeter pitch CdZnTe strip detector. The detector is a prototype for γ-ray astronomy measurements in the range of 20-200 keV. The prototype is a 1.5 mm thick, 64 x 64 orthogonal stripe CdZnTe detector of 0.375 mm pitch in both dimensions, with approximately one square inch of sensitive area. Using discrete laboratory electronics to process signals from 8 x 8 stripe region of the prototype we measured good spectroscopic uniformity and sub-pitch (∼ 0.2 mm) spatial resolution in both x and y dimensions. We present below measurements of the spatial uniformity, relative timing and pulse height of the anode and cathode signals, and the photon detection efficiency. We also present a technique for determining the location of the event in the third dimension (depth). We simulated the photon interactions and signal generation in the strip detector and the test electronics and we compare these results with the data. The data indicate that cathode signal - as well as the anode signal - arises more strongly from the conduction electrons rather than the holes

Direct conversion Si and CdZnTe detectors for digital mammography

CERN Document Server

Yin Shi Shi; Maeding, D; Mainprize, J; Mawdsley, G; Yaffe, M J; Gordon, E E; Hamilton, W J

2000-01-01

Hybrid pixel detector arrays that convert X-rays directly into charge signals are under development at NOVA for application to digital mammography. This technology also has wide application possibilities in other fields of radiology or in industrial imaging, nondestructive evaluation (NDE) and nondestructive inspection (NDI). These detectors have potentially superior properties compared to either emulsion-based film-screen systems which has nonlinear response to X-rays, or phosphor-based detectors in which there is an intermediate step of X-ray to light photon conversion (Feig and Yaffe, Radiol. Clinics North America 33 (1995) 1205-1230). Potential advantages of direct conversion detectors are high quantum efficiencies (QE) of 98% or higher (for 0.3 mm thick CdZnTe detector with 20 keV X-rays), improved contrast, high sensitivity and low intrinsic noise. These factors are expected to contribute to high detective quantum efficiency (DQE). The prototype hybrid pixel detector developed has 50x50 mu m pixel size,...

Design of low noise front-end ASIC and DAQ system for CdZnTe detector

International Nuclear Information System (INIS)

Luo Jie; Deng Zhi; Liu Yinong

2012-01-01

A low noise front-end ASIC has been designed for CdZnTe detector. This chip contains 16 channels and each channel consists of a dual-stage charge sensitive preamplifier, 4th order semi-Gaussian shaper, leakage current compensation (LCC) circuit, discriminator and output buffer. This chip has been fabricated in Chartered 0.35 μm CMOS process, the preliminary results show that it works well. The total channel charge gain can be adjusted from 100 mV/fC to 400 mV/fC and the peaking time can be adjusted from 1 μs to 4 μs. The minimum measured ENC at zero input capacitance is 70 e and minimum noise slope is 20 e/pF. The peak detector and derandomizer (PDD) ASIC developed by BNL and an associated USB DAQ board are also introduced in this paper. Two front-end ASICs can be connected to the PDD ASIC on the USB DAQ board and compose a 32 channels DAQ system for CdZnTe detector. (authors)

Rapid pulse annealing of CdZnTe detectors for reducing electronic noise

Science.gov (United States)

Voss, Lars; Conway, Adam; Nelson, Art; Nikolic, Rebecca J.; Payne, Stephen A.; Swanberg, Jr., Erik Lars

2018-05-01

A combination of doping, rapid pulsed optical and/or thermal annealing, and unique detector structure reduces or eliminates sources of electronic noise in a CdZnTe (CZT) detector. According to several embodiments, methods of forming a detector exhibiting minimal electronic noise include: pulse-annealing at least one surface of a detector comprising CZT for one or more pulses, each pulse having a duration of .about.0.1 seconds or less. The at least one surface may optionally be ion-implanted. In another embodiment, a CZT detector includes a detector surface with two or more electrodes operating at different electric potentials and coupled to the detector surface; and one or more ion-implanted CZT surfaces on or in the detector surface, each of the one or more ion-implanted CZT surfaces being independently connected to one of the two or more electrodes and the surface of the detector. At least two of the ion-implanted surfaces are in electrical contact.

Computer controlled drifting of Si(Li) detectors

International Nuclear Information System (INIS)

Landis, D.A.; Wong, Y.K.; Walton, J.T.; Goulding, F.S.

1989-01-01

A relatively inexpensive computer-controlled system for performing the drift process used in fabricating Si(Li) detectors is described. The system employs a small computer to monitor the leakage current, applied voltage and temperature on eight individual drift stations. The associated computer program initializes the drift process, monitors the drift progress and then terminates the drift when an operator set drift time has elapsed. The improved control of the drift with this system has been well demonstrated over the past three years in the fabrication of a variety of Si(Li) detectors. A few representative system responses to detector behavior during the drift process are described

P-type silicon drift detectors

International Nuclear Information System (INIS)

Walton, J.T.; Krieger, B.; Krofcheck, D.; O'Donnell, R.; Odyniec, G.; Partlan, M.D.; Wang, N.W.

1995-06-01

Preliminary results on 16 CM 2 , position-sensitive silicon drift detectors, fabricated for the first time on p-type silicon substrates, are presented. The detectors were designed, fabricated, and tested recently at LBL and show interesting properties which make them attractive for use in future physics experiments. A pulse count rate of approximately 8 x l0 6 s -1 is demonstrated by the p-type silicon drift detectors. This count rate estimate is derived by measuring simultaneous tracks produced by a laser and photolithographic mask collimator that generates double tracks separated by 50 μm to 1200 μm. A new method of using ion-implanted polysilicon to produce precise valued bias resistors on the silicon drift detectors is also discussed

Study of CdTe:Cl and CdZnTe detectors for medical multi-slices X-ray Computed Tomography

International Nuclear Information System (INIS)

Ricq, St.

1999-01-01

The application of CdTe and CdZnTe detectors to medical X-ray Computed Tomography have been investigated. Different electrodes (Au, Pt, In) have been deposited on CdZnTe HPBM and on CdTe:ClTHM. Their injection properties have been determined with Current-Voltage characteristics. Under X-ray in CT conditions, injection currents measurements reveal trapped carriers space-charges formation. The same way, the comparisons of the responses to X-beam cut-off with various injection possibilities enable to follow the space-charges evolutions and then to determine the predominant traps types. Nevertheless, both hole and electron traps are responsible for the memory effect e.g. the currents levels dependence with irradiation history. This effect is noticed in particular on responses to fast flux variations that simulate scanner's conditions. Trap levels probably corresponding to native defects are responsible for these limitations. In order to make such detectors suitable for X-ray Computed Tomography, significant progresses in CdTe for CdZnTe crystal growth with an important defects densities reduction (factor 10), or possibly counting mode operation, seem necessary. (author)

CDZNTE ROOM-TEMPERATURE SEMICONDUCTOR GAMMA-RAY DETECTOR FOR NATIONAL-SECURITY APPLICATIONS.

Energy Technology Data Exchange (ETDEWEB)

CAMARDA,G.S.; BOLOTNIKOV, A.E.; CUI, Y.; HOSSAIN, A.; KOHMAN, K.T.; JAMES, R.B.

2007-05-04

One important mission of the Department of Energy's National Nuclear Security Administration is to develop reliable gamma-ray detectors to meet the widespread needs of users for effective techniques to detect and identify special nuclear- and radioactive-materials. Accordingly, the Nonproliferation and National Security Department at Brookhaven National Laboratory was tasked to evaluate existing technology and to develop improved room-temperature detectors based on semiconductors, such as CdZnTe (CZT). Our research covers two important areas: Improving the quality of CZT material, and exploring new CZT-based gamma-ray detectors. In this paper, we report on our recent findings from the material characterization and tests of actual CZT devices fabricated in our laboratory and from materials/detectors supplied by different commercial vendors. In particular, we emphasize the critical role of secondary phases in the current CZT material and issues in fabricating the CZT detectors, both of which affect their performance.

Electron injection in semiconductor drift detectors

International Nuclear Information System (INIS)

Rehak, P.; Gatti, E.; Longoni, A.; Sampietro, M.; Castoldi, A.; Vacchi, A.

1990-01-01

The paper reports the first successful results of a simple MOS structure to inject electrons at a given position in Silicon Drift Detectors. The structure allows on-line calibration of the drift velocity of electrons within the detector. The calibration is a practical method to trace the temperature dependence of the electron mobility. Several of these injection structures can be implemented in silicon drift detectors without additional steps in the fabrication process. 5 refs., 11 figs

Design and Measurement of a Low-Noise 64-Channels Front-End Readout ASIC for CdZnTe Detectors

Energy Technology Data Exchange (ETDEWEB)

Gan, Bo; Wei, Tingcun; Gao, Wu; Liu, Hui; Hu, Yann [School of Computer Science and Technology, Northwestern Polytechnical University, Xi' an (China)

2015-07-01

Cadmium zinc telluride (CdZnTe) detectors, as one of the principal detectors for the next-generation X-ray and γ-ray imagers, have high energy resolution and supporting electrode patterning in the radiation environment at room-temperature. In the present, a number of internationally renowned research institutions and universities are actively using these detector systems to carry out researches of energy spectrum analysis, medical imaging, materials characterization, high-energy physics, nuclear plant monitoring, and astrophysics. As the most important part of the readout system for the CdZnTe detector, the front-end readout application specific integrated circuit (ASIC) would have an important impact on the performances of the whole detector system. In order to ensure the small signal to noise ratio (SNR) and sufficient range of the output signal, it is necessary to design a front-end readout ASIC with very low noise and very high dynamic range. In addition, radiation hardness should be considered when the detectors are utilized in the space applications and high energy physics experiments. In this paper, we present measurements and performances of a novel multi-channel radiation-hardness low-noise front-end readout ASIC for CdZnTe detectors. The readout circuits in each channel consist of charge sensitive amplifier, leakage current compensation circuit (LCC), CR-RC shaper, S-K filter, inverse proportional amplifier, peak detect and hold circuit (PDH), discriminator and trigger logic, time sequence control circuit and driving buffer. All of 64 readout channels' outputs enter corresponding inputs of a 64 channel multiplexer. The output of the mux goes directly out of the chip via the output buffer. The 64-channel readout ASIC is implemented using the TSMC 0.35 μm mixed-signal CMOS technology. The die size of the prototype chip is 2.7 mm x 8 mm. At room temperature, the equivalent noise level of a typical channel reaches 66 e{sup -} (rms) at zero farad for a

Influence of hydrostatic pressure on nuclear radiation detector's properties based on semiconductor alloy CdZnTe

International Nuclear Information System (INIS)

Kutnij, V.E.; Kutnij, D.V.; Rybka, A.V.; Nakonechnyj, D.V.; Babun, A.V.

2003-01-01

The influence of hydrostatic pressure on properties of CdZnTe semiconductor detectors (Cd-50,Zn-2,Te-48 mas.%, 5 centre dot 5 centre dot 2 mm) was investigated. Were considered different types of hydrostatic treatment at 100 MPa, second hydrostatic treatment at 100 MPa and 200 MPa. Hydrostatic pressure influence on detectors electric resistance, J-V characteristics and spectrometric parameters was determined

Ruggedization of CdZnTe detectors and detector assemblies for radiation detection applications

Energy Technology Data Exchange (ETDEWEB)

Lu, P.H., E-mail: pinghe.lu@redlen.com; Gomolchuk, P.; Chen, H.; Beitz, D.; Grosser, A.W.

2015-06-01

This paper described improvements in the ruggedization of CdZnTe detectors and detector assemblies for use in radiation detection applications. Research included experimenting with various conductive and underfill adhesive material systems suitable for CZT substrates. A detector design with encapsulation patterning was developed to protect detector surfaces and to control spacing between CZT anode and PCB carrier. Robustness of bare detectors was evaluated through temperature cycling and metallization shear testing. Attachment processes using well-chosen adhesives and PCB carrier materials were optimized to improve reliability of detector assemblies, resulted in Improved Attachment Detector Assembly. These detector assemblies were subjected to aggressive temperature cycling, and varying levels of drop/shock and vibration, in accordance with modified JEDEC, ANSI and FedEx testing standards, to assess their ruggedness. Further enhanced detector assembly ruggedization methods were investigated involving adhesive conformal coating, potting and dam filling on detector assemblies, which resulted in the Enhanced Ruggedization Detector Assembly. Large numbers of CZT detectors and detector assemblies with 5 mm and 15 mm thick, over 200 in total, were tested. Their performance was evaluated by exposure to various radioactive sources using comprehensive predefined detector specifications and testing protocols. Detector assemblies from improved attachment and enhanced ruggedization showed stable performances during the harsh environmental condition tests. In conclusion, significant progress has been made in improving the reliability and enhancing the ruggedness of CZT detector assemblies for radiation detection applications deployed in operational environments. - Highlights: • We developed ruggedization methods to enhance reliability of CZT detector assemblies. • Attachment of CZT radiation detectors was improved through comparative studies. • Bare detector metallization

A novel silicon drift detector with two dimensional drift time measurement

International Nuclear Information System (INIS)

Hijzen, E.A.; Schooneveld, E.M.; Van Eijk, C.W.E.; Hollander, R.W.; Sarro, P.M.; Van den Bogaard, A.

1994-01-01

Until now silicon drift detectors with two dimensional position resolution made use of drift time measurement in one dimension only. The resolution in the other dimension was obtained by dividing the collecting anode into small pixels. In this paper we present a new type of drift detector that uses drift time measurements for both dimensions. The design consists of concentric quadrilateral closed strips with a small collecting anode in the centre. At first electrons will travel perpendicular to the strips until they reach a diagonal. Then they will proceed along this diagonal until they are collected at the centre. Position resolution in two dimensions can be obtained when both the time the electrons need to reach the diagonal and the time they need to reach the centre are measured. The latter is obtained from the collecting anode, the former from a diagonal strip present at the back side of the detector. Compared to common 2D drift detectors this detector offers the advantage of a small amount of readout electronics. It also has the advantage of having just one small collecting anode with a very low capacitance, resulting in low noise and therefore in a good energy resolution. ((orig.))

Operation of CdZnTe Semiconductor Detectors in Liquid Scintillator for the COBRA Experiment

International Nuclear Information System (INIS)

Oldorf, Christian

2015-08-01

COBRA, the Cadmium-Zinc-Telluride O-neutrino double-Beta Research Apparatus, is an experiment aiming for the measurement of the neutrinoless double beta decay with several isotopes, in particular 116 Cd, 106 Cd and 130 Te. A highly granular large scale experiment with about 400 kg of CdZnTe semiconductor detectors is currently under development. To provide evidence for the neutrinoless double beta decay of 116 Cd, a background rate in the order of 10 -3 counts/keV/kg/a is needed to achieve the required half-life sensitivity of at least 2 . 10 26 years. To reach this target, the detectors have to be operated in a highly pure environment, shielded from external radiation. Liquid scintillator is a promising candidate as a circum fluent replacement for the currently used lacquer. Next to the function as highly pure passivation material, liquid scintillator also acts as a neutron shield and active veto for external gammas. Within this thesis, the design, construction and assembly of a test set-up is described. The operation of four CdZnTe detectors after several years of storage in liquid scintillator is demonstrated. Next to extensive material compatibility tests prior to the assembly, the commissioning of the set-up and the characterization of the detectors are shown. Finally, results concerning the background reduction capability of liquid scintillator and the detection of cosmic muons are presented and compared to a Monte Carlo simulation.

Development of flat panel X-ray detector utilizing a CdZnTe film as conversion layer

International Nuclear Information System (INIS)

Tokuda, Satoshi; Kishihara, Hiroyuki; Kaino, Masatomo; Sato, Toshiyuki

2006-01-01

A polycrystalline CdZnTe film formed by the CSS (closed-spaced sublimation) method is one of the most promising materials as a conversion layer of next-generation highly efficient flat-panel X-ray detectors. Therefore, we have developed a prototype of a new flat-panel X-ray detector (a sensing region of 3 inches by 3 inches) with the film and evaluated its commercial feasibility. This paper describes evaluation of the physical and imaging properties of the prototype and explains the features of the CdZnTe film and the construction, specifications, and fabrication procedures of the prototype. Also included in this paper are formation of a semiconductor thin film barrier layer by the CBD (chemical bath deposition) method and conjunction of a sensor substrate and a TFT array substrate with the bump electrodes formed by screen printing, both of which we have developed during the course of the development of the prototype. (author)

Silicon drift detectors, present and future prospects

Science.gov (United States)

Takahashi, J.; Bellwied, R.; Beuttenmuller, R.; Caines, H.; Chen, W.; Dyke, H.; Hoffmann, G. W.; Humanic, T.; Kotov, I.; Kuczewski, P.; Leonhardt, W.; Li, Z.; Lynn, D.; Minor, R.; Munhoz, M.; Ott, G.; Pandey, S. U.; Schambach, J.; Soja, R.; Sugarbaker, E.; Willson, R. M.

2001-04-01

Silicon drift detectors provide unambiguous two-dimensional position information for charged particle detection with a single detector layer. A large area silicon drift detector was developed for the inner tracking detector of the STAR experiment at RHIC. In this paper, we discuss the lessons learned and the future prospects of this technology.

Electron drift time in silicon drift detectors: A technique for high precision measurement of electron drift mobility

International Nuclear Information System (INIS)

Castoldi, A.; Rehak, P.

1995-01-01

This paper presents a precise absolute measurement of the drift velocity and mobility of electrons in high resistivity silicon at room temperature. The electron velocity is obtained from the differential measurement of the drift time of an electron cloud in a silicon drift detector. The main features of the transport scheme of this class of detectors are: the high uniformity of the electron motion, the transport of the signal electrons entirely contained in the high-purity bulk, the low noise timing due to the very small anode capacitance (typical value 100 fF), and the possibility to measure different drift distances, up to the wafer diameter, in the same semiconductor sample. These features make the silicon drift detector an optimal device for high precision measurements of carrier drift properties. The electron drift velocity and mobility in a 10 kΩ cm NTD n-type silicon wafer have been measured as a function of the electric field in the range of possible operation of a typical drift detector (167--633 V/cm). The electron ohmic mobility is found to be 1394 cm 2 /V s. The measurement precision is better than 1%. copyright 1995 American Institute of Physics

Characterization of a large-format, fine-pitch CdZnTe pixel detector for the HEFT balloon-Borne experiment

OpenAIRE

Chen, C. M. Hubert; Cook, Walter R.; Harrison, Fiona A.; Lin, Jiao Y. Y.

2004-01-01

We have developed a large-format CdZnTe pixel detector with custom, low-noise ASIC readout, for astrophysical applications. In particular, this detector is targeted for use in the High-Energy Focusing Telescope (HEFT), a balloon-borne experiment with focusing optics for 20-70 keV. The detector is a 24 X 44 pixel array of 498-µm pitch. As a focal plane detector, uniformity from pixel to pixel is very desirable. In this paper, we present the characterization of some detector properties for the ...

Evaluation of CdZnTe as neutron detector around medical accelerators

International Nuclear Information System (INIS)

Martin-Martin, A.; Iniguez, M. P.; Luke, P. N.; Barquero, R.; Lorente, A.; Morchon, J.; Gallego, E.; Quincoces, G.; Marti-Climent, J. M.

2009-01-01

The operation of electron linear accelerators (LINACs) and cyclotrons can produce a mixed gamma-neutron field composed of energetic neutrons coming directly from the source and scattered lower energy neutrons. The thermal neutron detection properties of a non-moderated coplanar-grid CdZnTe (CZT) gamma-ray detector close to an 18 MV electron LINAC and an 18 MeV proton cyclotron producing the radioisotope 18 F for positron emission tomography are investigated. The two accelerators are operated at conditions producing similar thermal neutron fluence rates of the order of 104 cm -2 s -1 at the measurement locations. The counting efficiency of the CZT detector using the prompt 558 keV photopeak following 113 Cd thermal neutron capture is evaluated and a good neutron detection performance is found at the two installations. (authors)

Study of CdTe:Cl and CdZnTe detectors for medical multi-slices X-ray Computed Tomography; Etude de detecteurs en CdTe:Cl et CdZnTe pour la tomographie X medicale multicoupes

Energy Technology Data Exchange (ETDEWEB)

Ricq, St

1999-09-28

The application of CdTe and CdZnTe detectors to medical X-ray Computed Tomography have been investigated. Different electrodes (Au, Pt, In) have been deposited on CdZnTe HPBM and on CdTe:ClTHM. Their injection properties have been determined with Current-Voltage characteristics. Under X-ray in CT conditions, injection currents measurements reveal trapped carriers space-charges formation. The same way, the comparisons of the responses to X-beam cut-off with various injection possibilities enable to follow the space-charges evolutions and then to determine the predominant traps types. Nevertheless, both hole and electron traps are responsible for the memory effect e.g. the currents levels dependence with irradiation history. This effect is noticed in particular on responses to fast flux variations that simulate scanner's conditions. Trap levels probably corresponding to native defects are responsible for these limitations. In order to make such detectors suitable for X-ray Computed Tomography, significant progresses in CdTe for CdZnTe crystal growth with an important defects densities reduction (factor 10), or possibly counting mode operation, seem necessary. (author)

CdZnTe background measurements at balloon altitudes with PoRTIA

International Nuclear Information System (INIS)

Parsons, A.; Barthelmy, S.; Bartlett, L.; Gehrels, N.; Naya, J.; Stahle, C.M.; Tueller, J.; Teegarden, B.

2004-01-01

Measurements of the CdZnTe internal background at balloon altitudes are essential to determine which physical processes make the most important background contributions. We present results from CdZnTe background measurements made by PoRTIA, a small CdZnTe balloon instrument that was flown three times in three different shielding configurations. PoRTIA was passively shielded during its first flight from Palestine, Texas and actively shielded as a piggyback instrument on the GRIS balloon experiment during its second and third flights from Alice Springs, Australia, using the thick GRIS NaI anticoincidence shield. A significant CdZnTe background reduction was achieved during the third flight with PoRTIA placed completely inside the GRIS shield and blocking crystal, and thus completely surrounded by 15 cm of NaI. A unique balloon altitude background data set is provided by CdZnTe and Ge detectors simultaneously surrounded by the same thick anticoincidence shield; the presence of a single coaxial Ge detector inside the shield next to PoRTIA allowed a measurement of the ambient neutron flux inside the shield throughout the flight. These neutrons interact with the detector material to produce isomeric states of the Cd, Zn, and Te nuclei that radiatively decay; calculations are presented to determine the relative contribution of these decays to the fully shielded CdZnTe background measured by PoRTIA

Detection of electron and hole traps in CdZnTe radiation detectors by thermoelectric emission spectroscopy and thermally stimulated conductivity

International Nuclear Information System (INIS)

Lee, E.Y.; Brunett, B.A.; Olsen, R.W.; Van Scyoc, J.M. III; Hermon, H.; James, R.B.

1998-01-01

The electrical properties of CdZnTe radiation detectors are largely determined by electron and hole traps in this material. The traps, in addition to degrading the detector performance, can function as dopants and determine the resistivity of the material. Thermoelectric emission spectroscopy and thermally stimulated conductivity are used to detect these traps in a commercially available spectrometer-grade CdZnTe detector, and the electrical resistivity is measured as a function of temperature. A deep electron trap having an energy of 695 meV and cross section of 8 x 10 -16 cm 2 is detected and three hole traps having energies of 70 ± 20 meV, 105 ± 30 meV and 694 ± 162 meV are detected. A simple model based on these traps explains quantitatively all the data, including the electrical properties at room temperature and also their temperature dependence

Characterisation of Redlen high-flux CdZnTe

Science.gov (United States)

Thomas, B.; Veale, M. C.; Wilson, M. D.; Seller, P.; Schneider, A.; Iniewski, K.

2017-12-01

CdZnTe is a promising material for the current generation of free electron laser light sources and future laser-driven γ-ray sources which require detectors capable of high flux imaging at X-ray and γ-ray energies (> 10 keV) . However, at high fluxes CdZnTe has been shown to polarise due to hole trapping, leading to poor performance. Novel Redlen CdZnTe material with improved hole transport properties has been designed for high flux applications. Small pixel CdZnTe detectors were fabricated by Redlen Technologies and flip-chip bonded to PIXIE ASICs. An XIA Digital Gamma Finder PIXIE-16 system was used to digitise each of the nine analogue signals with a timing resolution of 10 ns. Pulse shape analysis was used to extract the rise times and amplitude of signals. These were measured as a function of applied bias voltage and used to calculate the mobility (μ) and mobility-lifetime (μτ) of electrons and holes in the material for three identical detectors. The measured values of the transport properties of electrons in the high-flux-capable material was lower than previously reported for Redlen CdZnTe material (μeτe ~ 1 × 10-3 cm2V-1 and μe ~ 1000 cm2V-1s-1) while the hole transport properties were found to have improved (μhτh ~ 3 × 10-4 cm2V-1 and μh ~ 100 cm2V-1s-1).

Semiconductor X-ray detectors

CERN Document Server

Lowe, Barrie Glyn

2014-01-01

Identifying and measuring the elemental x-rays released when materials are examined with particles (electrons, protons, alpha particles, etc.) or photons (x-rays and gamma rays) is still considered to be the primary analytical technique for routine and non-destructive materials analysis. The Lithium Drifted Silicon (Si(Li)) X-Ray Detector, with its good resolution and peak to background, pioneered this type of analysis on electron microscopes, x-ray fluorescence instruments, and radioactive source- and accelerator-based excitation systems. Although rapid progress in Silicon Drift Detectors (SDDs), Charge Coupled Devices (CCDs), and Compound Semiconductor Detectors, including renewed interest in alternative materials such as CdZnTe and diamond, has made the Si(Li) X-Ray Detector nearly obsolete, the device serves as a useful benchmark and still is used in special instances where its large, sensitive depth is essential. Semiconductor X-Ray Detectors focuses on the history and development of Si(Li) X-Ray Detect...

Study of CdTe:Cl and CdZnTe detectors for medical multi-slices X-ray Computed Tomography; Etude de detecteurs en CdTe:Cl et CdZnTe pour la tomographie X medicale multicoupes

Energy Technology Data Exchange (ETDEWEB)

Ricq, St

1999-09-28

The application of CdTe and CdZnTe detectors to medical X-ray Computed Tomography have been investigated. Different electrodes (Au, Pt, In) have been deposited on CdZnTe HPBM and on CdTe:ClTHM. Their injection properties have been determined with Current-Voltage characteristics. Under X-ray in CT conditions, injection currents measurements reveal trapped carriers space-charges formation. The same way, the comparisons of the responses to X-beam cut-off with various injection possibilities enable to follow the space-charges evolutions and then to determine the predominant traps types. Nevertheless, both hole and electron traps are responsible for the memory effect e.g. the currents levels dependence with irradiation history. This effect is noticed in particular on responses to fast flux variations that simulate scanner's conditions. Trap levels probably corresponding to native defects are responsible for these limitations. In order to make such detectors suitable for X-ray Computed Tomography, significant progresses in CdTe for CdZnTe crystal growth with an important defects densities reduction (factor 10), or possibly counting mode operation, seem necessary. (author)

Recent advances in Tl Br, Cd Te and CdZnTe semiconductor radiation detectors: a review

International Nuclear Information System (INIS)

Oliveira, Icimone B.

2011-01-01

The success in the development of radiation spectrometers operating at room temperature is based on many years of effort on the part of large numbers of workers around the world. These individuals have contributed to the understanding of the fundamental materials issues associated with the growth of semiconductors for this application, the development of device fabrication and processing technology, and advances in low noise electronics and pulse processing. Progress in this field continues at an accelerated pace, as in evidenced by the improvements in detector performance and by the growing number of commercial products. Thus, the last years have been seen continued effort in the development of room temperature compound semiconductors devices. High-Z compound semiconductor detectors has been explored for high energy resolution, high detection efficiency and are of low cost. Compound semiconductors detectors are well suited for addressing needs of demanding applications such as bore hole logging where high operating temperature are encountered. In this work recent developments in semiconductors detectors were reviewed. This review concentrated on thallium bromide (TlBr), cadmium zinc telluride (CdZnTe) and cadmium telluride (CdTe) crystals detectors. TlBr has higher stopping power compared to common semiconductor materials because it has the higher photoelectric and total attenuation coefficients over wide energy range from 100 keV to 1 MeV. CdTe and CdZnTe detectors have several attractive features for detecting X-ray and low energy gamma ray. Their relatively large band gaps lead to a relatively low leakage current and offer an excellent energy resolution at room temperature. A literature survey and bibliography was also included. (author)

Recent advances in Tl Br, Cd Te and CdZnTe semiconductor radiation detectors: a review

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Icimone B. [Universidade Bandeirante (UNIBAN), Sao Paulo, SP (Brazil)

2011-07-01

The success in the development of radiation spectrometers operating at room temperature is based on many years of effort on the part of large numbers of workers around the world. These individuals have contributed to the understanding of the fundamental materials issues associated with the growth of semiconductors for this application, the development of device fabrication and processing technology, and advances in low noise electronics and pulse processing. Progress in this field continues at an accelerated pace, as in evidenced by the improvements in detector performance and by the growing number of commercial products. Thus, the last years have been seen continued effort in the development of room temperature compound semiconductors devices. High-Z compound semiconductor detectors has been explored for high energy resolution, high detection efficiency and are of low cost. Compound semiconductors detectors are well suited for addressing needs of demanding applications such as bore hole logging where high operating temperature are encountered. In this work recent developments in semiconductors detectors were reviewed. This review concentrated on thallium bromide (TlBr), cadmium zinc telluride (CdZnTe) and cadmium telluride (CdTe) crystals detectors. TlBr has higher stopping power compared to common semiconductor materials because it has the higher photoelectric and total attenuation coefficients over wide energy range from 100 keV to 1 MeV. CdTe and CdZnTe detectors have several attractive features for detecting X-ray and low energy gamma ray. Their relatively large band gaps lead to a relatively low leakage current and offer an excellent energy resolution at room temperature. A literature survey and bibliography was also included. (author)

Principle and applications of Controlled-Drift Detectors

International Nuclear Information System (INIS)

Castoldi, A.; Guazzoni, C.; Hartmann, R.; Strueder, L.

2007-01-01

The Controlled-Drift Detector is a fully depleted silicon detector that allows 2D position sensing and energy spectroscopy of X-rays in the range 0.5-30 keV with imaging capability up to 100 kframe/s, event timing of few ns and limited readout channels. In this paper we review the Controlled-Drift Detector operating principle and we present its applications in X-ray absorption imaging and in Compton electrons tracking

Microsecond-scale X-ray imaging with Controlled-Drift Detectors

International Nuclear Information System (INIS)

Castoldi, A.; Galimberti, A.; Guazzoni, C.; Rehak, P.; Strueder, L.

2006-01-01

The Controlled-Drift Detector is a fully-depleted silicon detector that allows 2-D position sensing and energy spectroscopy of X-rays in the range 0.5-20keV with excellent time resolution (few tens of μs) and limited readout channels. In this paper we review the Controlled-Drift Detector operating principle and we present the X-ray imaging and spectroscopic capabilities of Controlled Drift Detectors in microsecond-scale experiments and the more relevant applications fields

Performance optimization of CdTe and CdZnTe detectors for γ-spectrometry

International Nuclear Information System (INIS)

Montemont, Guillaume

2000-01-01

This study deals with room-temperature gamma spectrometry with CdTe and CdZnTe semiconductor detectors. The aim was the improvement of energy resolution and detection efficiency. Some different phenomena have been investigated. Electronic noise knowledge has enabled us to optimize the design of filtering. Charge transport induces signal shape uncertainty and the processing circuit has been adapted in order to account for these variations. Study and simulation of electrical current induction process has permitted the development of a new Frisch-grid based detection structure. We have reached 3% energy resolutions at 122 keV without detection efficiency loss. Finally, the remaining limits of detector performances have been estimated by focusing on gamma interaction phenomena and material non-uniformity problems. (author) [fr

Simulation of the anode structure for capacitive frisch grid CdZnTe detectors

International Nuclear Information System (INIS)

Min Jiahua; Shi Zhubin; Sang Wenbin; Zhao Hengyu; Teng Jianyong; Qian Yongbiao; Liu Jishan

2009-01-01

CdZnTe (CZT) capacitive Frisch grid detectors can achieve a higher detecting resolution. The anode structrure might have an important role in improving the weighting potential distribution of the detectors. In this paper, four anode structures of capacitive Frisch grid structures have been analyzed with FE simulation, based on a 3-dimensional weighting potential analysis. The weighting potential distributions in modified anode devices (Model B, C and D) are optimized compared with a square device (Model A). In model C and D, the abrupt weighting potential can be well modified. However, with increased radius of the circular electrode in Model C the weighting potential platform away from the anode becomes higher and higher and in Model D, the weighting potential does not vary too much. (authors)

Silicon Drift Detectors - A Novel Technology for Vertex Detectors

Science.gov (United States)

Lynn, D.

1996-10-01

Silicon Drift Detectors (SDD) are novel position sensing silicon detectors which operate in a manner analogous to gas drift detectors. Single SDD's were shown in the CERN NA45 experiment to permit excellent spatial resolution (pseudo-rapidity. Over the last three years we undertook a concentrated R+D effort to optimize the performance of the detector by minimizing the inactive area, the operating voltage and the data volume. We will present test results from several wafer prototypes. The charge produced by the passage of ionizing particles through the bulk of the detectors is collected on segmented anodes, with a pitch of 250 μm, on the far edges of the detector. The anodes are wire-bonded to a thick film multi-chip module which contains preamplifier/shaper chips and CMOS based switched capacitor arrays used as an analog memory pipeline. The ADC is located off-detector. The complete readout chain from the wafer to the DAQ will be presented. Finally we will show physics performance simulations based on the resolution achieved by the SVT prototypes.

Performance of silicon drift detectors in a magnetic field

International Nuclear Information System (INIS)

Castoldi, A.; Gatti, E.; Manzari, V.; Rehak, P.

1997-01-01

A study of the properties of silicon drift detectors in a magnetic field was carried out. A silicon drift detector with 41 anodes, providing unambiguous x and y position information, was used for measurements. Studies were done in three principal orientations of the detector relative to the direction of the magnetic field. The magnetic field was varied between 0 and 0.7 T and the drift field between 300 and 600 V/cm. Basic agreement with the theory of electron transport in semiconductors in a magnetic field was found. The transport properties of electrons in a magnetic field can be described by a mobility matrix. The components of the matrix depend on the electron mobility, Hall mobility and on the vector of the magnetic field. The precision of measurement was better than 0.2% for most of the parameters. For the electric field of a silicon drift detector, there is a first-order effect of the magnetic field only in one out of three principal directions. In this direction, the plane of the detector is perpendicular to the magnetic field and electrons drift at an angle α relative to the direction of the drift field. In two other principal directions, which are more important for tracking of the particles with drift detectors, there are no first-order magnetic effects. (orig.)

Performance of prototype segmented CdZnTe arrays

International Nuclear Information System (INIS)

Parsons, A.; Palmer, D.M.; Kurczynski, P.; Barbier, L.; Barthelmy, S.; Bartlett, L.; Gehrels, N.; Krizmanic, J.; Stahle, C.M.; Tueller, J.; Teegarden, B.

1998-01-01

The Burst and All Sky Imaging Survey (BASIS) is a proposed mission to provide ∼3 arc second locations of approximately 90 Gamma-Ray Bursts (GRBs) per year. The BASIS coded aperture imaging system requires a segmented detector plane able to detect the interaction position of (10--150 keV) photons to less than 100 microm. To develop prototype detector arrays with such fine position resolution the authors have fabricated many 15 mm x 15 mm x 2 mm 100 microm pitch CdZnTe strip detectors. They have assembled these fine pitch CdZnTe strip detectors into prototype 2 x 2 and 6 x 6 element arrays read out by ASIC electronics. The assembly and electronics readout of the 6 x 6 flight prototype array will be discussed, and preliminary data illustrating the uniformity and efficiency of the array will be presented

Optimal configuration of a low-dose breast-specific gamma camera based on semiconductor CdZnTe pixelated detectors

Science.gov (United States)

Genocchi, B.; Pickford Scienti, O.; Darambara, DG

2017-05-01

Breast cancer is one of the most frequent tumours in women. During the ‘90s, the introduction of screening programmes allowed the detection of cancer before the palpable stage, reducing its mortality up to 50%. About 50% of the women aged between 30 and 50 years present dense breast parenchyma. This percentage decreases to 30% for women between 50 to 80 years. In these women, mammography has a sensitivity of around 30%, and small tumours are covered by the dense parenchyma and missed in the mammogram. Interestingly, breast-specific gamma-cameras based on semiconductor CdZnTe detectors have shown to be of great interest to early diagnosis. Infact, due to the high energy, spatial resolution, and high sensitivity of CdZnTe, molecular breast imaging has been shown to have a sensitivity of about 90% independently of the breast parenchyma. The aim of this work is to determine the optimal combination of the detector pixel size, hole shape, and collimator material in a low dose dual head breast specific gamma camera based on a CdZnTe pixelated detector at 140 keV, in order to achieve high count rate, and the best possible image spatial resolution. The optimal combination has been studied by modeling the system using the Monte Carlo code GATE. Six different pixel sizes from 0.85 mm to 1.6 mm, two hole shapes, hexagonal and square, and two different collimator materials, lead and tungsten were considered. It was demonstrated that the camera achieved higher count rates, and better signal-to-noise ratio when equipped with square hole, and large pixels (> 1.3 mm). In these configurations, the spatial resolution was worse than using small pixel sizes (< 1.3 mm), but remained under 3.6 mm in all cases.

Instrumentation effects on U and Pu CBNM standards spectra quality measured on a 500 mm3 CdZnTe and a 2×2 inch LaBr3 detectors

Science.gov (United States)

Meleshenkovskii, I.; Borella, A.; Van der Meer, K.; Bruggeman, M.; Pauly, N.; Labeau, P. E.; Schillebeeckx, P.

2018-01-01

Nowadays, there is interest in developing gamma-ray measuring devices based on the room temperature operated medium resolution detectors such as semiconductor detectors of the CdZnTe type and scintillators of the LaBr3 type. This is true also for safeguards applications and the International Atomic Energy Agency (IAEA) has launched a project devoted to the assessment of medium resolution gamma-ray spectroscopy for the verification of the isotopic composition of U and Pu bearing samples. This project is carried out within the Non-Destructive Assay Working Group of the European Safeguards Research and Development Association (ESARDA). In this study we analyze medium resolution spectra of U and Pu standards with the aim to develop an isotopic composition determination algorithm, particularly suited for these types of detectors. We show how the peak shape of a CdZnTe detector is influenced by the instrumentation parameters. The experimental setup consisted of a 500 mm3 CdZnTe detector, a 2×2 inch LaBr3 detector, two types of measurement instrumentation - an analogue one and a digital one, and a set of certified samples - a 207Bi point source and U and Pu CBNM standards. The results of our measurements indicate that the lowest contribution to the peak asymmetry and thus the smallest impact on the resolution of the 500 mm3 CdZnTe detector was achieved with the digital MCA. Analysis of acquired spectra allowed to reject poor quality measurement runs and produce summed spectra files with the least impact of instrumentation instabilities. This work is preliminary to further studies concerning the development of an isotopic composition determination algorithm particularly suited for CZT and LaBr3 detectors for safeguards applications.

Comparison of CdZnTe neutron detector models using MCNP6 and Geant4

Science.gov (United States)

Wilson, Emma; Anderson, Mike; Prendergasty, David; Cheneler, David

2018-01-01

The production of accurate detector models is of high importance in the development and use of detectors. Initially, MCNP and Geant were developed to specialise in neutral particle models and accelerator models, respectively; there is now a greater overlap of the capabilities of both, and it is therefore useful to produce comparative models to evaluate detector characteristics. In a collaboration between Lancaster University, UK, and Innovative Physics Ltd., UK, models have been developed in both MCNP6 and Geant4 of Cadmium Zinc Telluride (CdZnTe) detectors developed by Innovative Physics Ltd. Herein, a comparison is made of the relative strengths of MCNP6 and Geant4 for modelling neutron flux and secondary γ-ray emission. Given the increasing overlap of the modelling capabilities of MCNP6 and Geant4, it is worthwhile to comment on differences in results for simulations which have similarities in terms of geometries and source configurations.

Characterising large area silicon drift detectors with MOS injectors

International Nuclear Information System (INIS)

Bonvicini, V.; Rashevsky, A.; Vacchi, A.

1999-01-01

In the framework of the INFN DSI project, the first prototypes of a large-area Silicon Drift Detector (SDD) have been designed and produced on 5'' diameter wafers of Neutron Transmutation Doped (NTD) silicon with a resistivity of 3000 Ω·cm. The detector is a 'butterfly' bi-directional structure with a drift length of 32 mm and the drifting charge is collected by two arrays of anodes having a pitch of 200 μm. The high-voltage divider is integrated on-board and is realised with p + implantations. For test and calibration purposes, the detector has a new type of MOS injector. The paper presents results obtained to injecting charge at the maximum drift distance (32mm) from the anodes by means of the MOS injecting structure, As front-end electronics, the authors have used a 32-channels low-noise bipolar VLSI circuit (OLA, Omni-purpose Low-noise Amplifer) specifically designed for silicon drift detectors. The uniformity of the drift time in different regions of the sensitive area and its dependence on the ambient temperature are studied

Purification of CdZnTe by electromigration

Science.gov (United States)

Kim, K.; Kim, Sangsu; Hong, Jinki; Lee, Jinseo; Hong, Taekwon; Bolotnikov, A. E.; Camarda, G. S.; James, R. B.

2015-04-01

Electro-migration of ionized/electrically active impurities in CdZnTe (CZT) was successfully demonstrated at elevated temperature with an electric field of 20 V/mm. Copper, which exists in positively charged states, electro-migrated at a speed of 15 μm/h in an electric field of 20 V/mm. A notable variation in impurity concentration along the growth direction with the segregation tendency of the impurities was observed in an electro-migrated CZT boule. Notably, both Ga and Fe, which exist in positively charged states, exhibited the opposite distribution to that of their segregation tendency in Cd(Zn)Te. A CZT detector fabricated from the middle portion of the electro-migrated CZT boule showed an improved mobility-lifetime product of 0.91 × 10-2 cm2/V, compared with that of 1.4 × 10-3 cm2/V, observed in an as-grown (non-electro-migrated) CZT detector. The optimum radiation detector material would have minimum concentration of deep traps required for compensation.

Clustering method to process signals from a CdZnTe detector

International Nuclear Information System (INIS)

Zhang, Lan; Takahashi, Hiroyuki; Fukuda, Daiji; Nakazawa, Masaharu

2001-01-01

The poor mobility of holes in a compound semiconductor detector results in the imperfect collection of the primary charge deposited in the detector. Furthermore the fluctuation of the charge loss efficiency due to the change in the hole collection path length seriously degrades the energy resolution of the detector. Since the charge collection efficiency varies with the signal waveform, we can expect the improvement of the energy resolution through a proper waveform signal processing method. We developed a new digital signal processing technique, a clustering method which derives typical patterns containing the information on the real situation inside a detector from measured signals. The obtained typical patterns for the detector are then used for the pattern matching method. Measured signals are classified through analyzing the practical waveform variation due to the charge trapping, the electric field and the crystal defect etc. Signals with similar shape are placed into the same cluster. For each cluster we calculate an average waveform as a reference pattern. Using these reference patterns obtained from all the clusters, we can classify other measured signal waveforms from the same detector. Then signals are independently processed according to the classified category and form corresponding spectra. Finally these spectra are merged into one spectrum by multiplying normalization coefficients. The effectiveness of this method was verified with a CdZnTe detector of 2 mm thick and a 137 Cs gamma-ray source. The obtained energy resolution as improved to about 8 keV (FWHM). Because the clustering method is only related to the measured waveforms, it can be applied to any type and size of detectors and compatible with any type of filtering methods. (author)

Study and modelling of the new generation Cd(Zn)Te X and gamma-ray detectors for space applications

International Nuclear Information System (INIS)

Dirks, Bob-Petrus-Franciscus

2006-01-01

The scientific astrophysics community needs a new instrument to gain more insight in the origin of the cosmic X-ray background, the physics of black holes and particle acceleration mechanisms in the energy range between 0.5 to 80 keV. Existing instruments like Chandra and XMM-Newton show very good results up to ∼10 keV but lack sufficient sensitivity above this value. In order to keep or improve the same performances up to ∼80 keV, grazing incidence mirrors with a large focal length of at least 20 m should be used. Since satellites this big cannot be launched with existing launchers, the mirror and detector must be placed on two different satellites flying in formation. The Simbol-X space mission will be the first project of this type. A high sensitivity at 80 keV requires not only a long focal length but also a detection unit with high spatial resolution, using detectors that are still efficient at these relatively high energies. CEA/Saclay/DAPNIA is developing this crucial element for the Simbol-X space mission. The imager consists of several modules, each built from individual X-ray mini-cameras. A single camera is a hybridisation of custom read-out electronics connected to a Cd(Zn)Te semiconductor crystal. The ensemble must be able to efficiently detect photons of up to 80 keV with an energy resolution of ∼1.3 keV (FWHM) at 68 keV. Furthermore it must be equipped with small pixels (∼500*500 μm"2) to attain the desired spatial resolution of 15 arcsec. In order to reach a good sensitivity and energy resolution, ultra-low noise read-out electronics in combination with high-quality semiconductor crystals are mandatory. The read-out electronics, baptised IDeF-X (Imaging Detector Front-end for X-rays), is also developed by CEA/Saclay. A thorough understanding of its functioning as well as its testing forms a part of this work. The spectroscopic performance of the detector is directly related to the electronics noise. The noise characteristics of the ASIC are

Application of CdZnTe Gamma-Ray Detector for Imaging Corrosion under Insulation

International Nuclear Information System (INIS)

Abdullah, J.; Yahya, R.

2007-01-01

Corrosion under insulation (CUI) on the external wall of steel pipes is a common problem in many types of industrial plants. This is mainly due to the presence of moisture or water in the insulation materials. This type of corrosion can cause failures in areas that are not normally of a primary concern to an inspection program. The failures are often the result of localised corrosion and not general wasting over a large area. These failures can tee catastrophic in nature or at least have an adverse economic effect in terms of downtime and repairs. There are a number of techniques used today for CUI investigations. The main ones are profile radiography, pulse eddy current, ultrasonic spot readings and insulation removal. A new system now available is portable Pipe-CUI-Profiler. The nucleonic system is based on dual-beam gamma-ray absorption technique using Cadmium Zinc Telluride (CdZnTe) semiconductor detectors. The Pipe-CUI-Profiler is designed to inspect pipes of internal diameter 50, 65, 80, 90, 100, 125 and 150 mm. Pipeline of these sizes with aluminium or thin steel sheathing, containing fibreglass or calcium silicate insulation to thickness of 25, 40 and 50 mm can be inspected. The system has proven to be a safe, fast and effective method of inspecting pipe in industrial plant operations. This paper describes the application of gamma-ray techniques and CdZnTe semiconductor detectors in the development of Pipe-CUI-Profiler for non-destructive imaging of corrosion under insulation of steel pipes. Some results of actual pipe testing in large-scale industrial plant will be presented

Application of CdZnTe Gamma-Ray Detector for Imaging Corrosion under Insulation

Science.gov (United States)

Abdullah, J.; Yahya, R.

2007-05-01

Corrosion under insulation (CUI) on the external wall of steel pipes is a common problem in many types of industrial plants. This is mainly due to the presence of moisture or water in the insulation materials. This type of corrosion can cause failures in areas that are not normally of a primary concern to an inspection program. The failures are often the result of localised corrosion and not general wasting over a large area. These failures can tee catastrophic in nature or at least have an adverse economic effect in terms of downtime and repairs. There are a number of techniques used today for CUI investigations. The main ones are profile radiography, pulse eddy current, ultrasonic spot readings and insulation removal. A new system now available is portable Pipe-CUI-Profiler. The nucleonic system is based on dual-beam gamma-ray absorption technique using Cadmium Zinc Telluride (CdZnTe) semiconductor detectors. The Pipe-CUI-Profiler is designed to inspect pipes of internal diameter 50, 65, 80, 90, 100, 125 and 150 mm. Pipeline of these sizes with aluminium or thin steel sheathing, containing fibreglass or calcium silicate insulation to thickness of 25, 40 and 50 mm can be inspected. The system has proven to be a safe, fast and effective method of inspecting pipe in industrial plant operations. This paper describes the application of gamma-ray techniques and CdZnTe semiconductor detectors in the development of Pipe-CUI-Profiler for non-destructive imaging of corrosion under insulation of steel pipes. Some results of actual pipe testing in large-scale industrial plant will be presented.

Organic Scintillator Detector Response Simulations with DRiFT

Energy Technology Data Exchange (ETDEWEB)

Andrews, Madison Theresa [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bates, Cameron Russell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mckigney, Edward Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rising, Michael Evan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pinilla, Maria Isabel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Solomon, Jr., Clell Jeffrey [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sood, Avneet [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-12-19

Accurate detector modeling is a requirement to design systems in many non-proliferation scenarios; by determining a Detector’s Response Function (DRF) to incident radiation, it is possible characterize measurements of unknown sources. DRiFT is intended to post-process MCNP® output and create realistic detector spectra. Capabilities currently under development include the simulation of semiconductor, gas, and (as is discussed in this work) scintillator detector physics. Energy spectra and pulse shape discrimination (PSD) trends for incident photon and neutron radiation have been reproduced by DRiFT.

Purification of CdZnTe by electromigration

International Nuclear Information System (INIS)

Kim, K.; Kim, Sangsu; Hong, Jinki; Lee, Jinseo; Hong, Taekwon; Bolotnikov, A. E.; Camarda, G. S.; James, R. B.

2015-01-01

Electro-migration of ionized/electrically active impurities in CdZnTe (CZT) was successfully demonstrated at elevated temperature with an electric field of 20 V/mm. Copper, which exists in positively charged states, electro-migrated at a speed of 15 μm/h in an electric field of 20 V/mm. A notable variation in impurity concentration along the growth direction with the segregation tendency of the impurities was observed in an electro-migrated CZT boule. Notably, both Ga and Fe, which exist in positively charged states, exhibited the opposite distribution to that of their segregation tendency in Cd(Zn)Te. A CZT detector fabricated from the middle portion of the electro-migrated CZT boule showed an improved mobility-lifetime product of 0.91 × 10 −2  cm 2 /V, compared with that of 1.4 × 10 −3  cm 2 /V, observed in an as-grown (non-electro-migrated) CZT detector. The optimum radiation detector material would have minimum concentration of deep traps required for compensation

Evaluation of prototype silicon drift detectors

International Nuclear Information System (INIS)

Ellison, J.; Hall, G.; Roe, S.; Lucas, A.

1988-01-01

Operating characteristics of several prototypes of silicon drift detectors are investigated. Detectors are made of unpolished silicon produced by the zone melting method and characterized by n-type conductivity and specific resistance of 3.6-4.6 kOhmxcm. The detectors comprise 40 parallel bands of 200 μm width and 1 cm length separated by 50 μm intervals. Data characterizing the potential distribution near anodes under the operating bias voltage, dependences of capacities and leakage as well as the detector space resolution

Investigation of long drift chambers for a nucleon-decay detector

International Nuclear Information System (INIS)

Price, L.E.; Dawson, J.; Ayres, D.; Denis, R.S.

1981-01-01

The use of long drift chambers for a nucleon-decay detector is discussed as a means of achieving a detector with very fine tracking, but with a modest number of readout channels. Strategies for reducing the attenuation of drifting electrons are considered, particularly the necessity of shaping the electric field to reduce the effects of diffusion and of nearby grounded conductors. Measured results are presented for a chamber with 1 cm drift gap and 50 cm maximum drift distance. The measured attenuation is 12%

THE 15 LAYER SILICON DRIFT DETECTOR TRACKER IN EXPERIMENT 896

International Nuclear Information System (INIS)

Pandey, S.U.

1998-01-01

Large linear silicon drift detectors have been developed and are in production for use in several experiments. Recently 15 detectors were used as a tracking device in BNL-AGS heavy ion experiment (E896). The detectors were successfully operated in a 6.2 T magnetic field. The behavior of the detectors, such as drift uniformity, resolution, and charge collection efficiency are presented. The effect of the environment on the detector performance is discussed. Some results from the experimental run are presented. The detectors performed well in an experimental environment. This is the first tracking application of these detectors

Method in analysis of CdZnTe γ spectrum with artificial neural network

International Nuclear Information System (INIS)

Ai Xianyun; Wei Yixiang; Xiao Wuyun

2005-01-01

The analysis of gamma-ray spectra to identify lines and their intensities usually requires expert knowledge and time consuming calculations with complex fitting functions. CdZnTe detector often exhibits asymmetric peak shape particularly at high energies making peak fitting methods and sophisticated isotope identification programs difficult to use. This paper investigates the use of the neural network to process gamma spectra measured with CdZnTe detector to verify nuclear materials. Results show that the neural network method gives advantages, in particular, when large low-energetic peak tailings are observed. (authors)

Ground calibration of the spatial response and quantum efficiency of the CdZnTe hard x-ray detectors for NuSTAR

Science.gov (United States)

Grefenstette, Brian W.; Bhalerao, Varun; Cook, W. Rick; Harrison, Fiona A.; Kitaguchi, Takao; Madsen, Kristin K.; Mao, Peter H.; Miyasaka, Hiromasa; Rana, Vikram

2017-08-01

Pixelated Cadmium Zinc Telluride (CdZnTe) detectors are currently flying on the Nuclear Spectroscopic Telescope ARray (NuSTAR) NASA Astrophysics Small Explorer. While the pixel pitch of the detectors is ≍ 605 μm, we can leverage the detector readout architecture to determine the interaction location of an individual photon to much higher spatial accuracy. The sub-pixel spatial location allows us to finely oversample the point spread function of the optics and reduces imaging artifacts due to pixelation. In this paper we demonstrate how the sub-pixel information is obtained, how the detectors were calibrated, and provide ground verification of the quantum efficiency of our Monte Carlo model of the detector response.

Silicon Drift Detectors development for position sensing

International Nuclear Information System (INIS)

Castoldi, A.; Guazzoni, C.; Hartmann, R.; Strueder, L.

2007-01-01

Novel Silicon Drift Detectors (SDDs) with multi-linear architecture specifically intended for 2D position sensing and imaging applications are presented and their achievable spatial, energy and time resolution are discussed. The capability of providing a fast timing of the interaction with nanosecond time resolution is a new available feature that allows operating the drift detector in continuous readout mode for coincidence imaging applications either with an external trigger or in self-timing. The application of SDDs with multi-linear architecture to Compton electrons' tracking within a single silicon layer and the achieved experimental results will be discussed

Spectroscopic measurements with a silicon drift detector having a continuous implanted drift cathode-voltage divider

CERN Document Server

Bonvicini, V; D'Acunto, L; Franck, D; Gregorio, A; Pihet, P; Rashevsky, A; Vacchi, A; Vinogradov, L I; Zampa, N

2000-01-01

A silicon drift detector (SDD) prototype where the drift electrode also plays the role of a high-voltage divider has been realised and characterised for spectroscopic applications at near-room temperatures. Among the advantages of this design, is the absence of metal on the sensitive surface which makes this detector interesting for soft X-rays. The detector prototype has a large sensitive area (2x130 mm sup 2) and the charge is collected by two anodes (butterfly-like detector). The energy resolution of a such a detector has been investigated at near-room temperatures using a commercial, hybrid, low-noise charge-sensitive preamplifier. The results obtained for the X-ray lines from sup 5 sup 5 Fe and sup 2 sup 4 sup 1 Am are presented.

Gamma spectrometric characterization of short cooling time nuclear spent fuels using hemispheric CdZnTe detectors

CERN Document Server

Lebrun, A; Szabó, J L; Arenas-Carrasco, J; Arlt, R; Dubreuil, A; Esmailpur-Kazerouni, K

2000-01-01

After years of cooling, nuclear spent fuel gamma emissions are mainly due to caesium isotopes which are emitters at 605, 662 and 796-801 keV. Extensive work has been done on such fuels using various CdTe or CdZnTe probes. When fuels have to be measured after short cooling time (during NPP outage) the spectrum is much more complex due to the important contributions of niobium and zirconium in the 700 keV range. For the first time in a nuclear power plant, four spent fuels of the Kozloduy VVER reactor no 4 were measured during outage, 37 days after shutdown of the reactor. In such conditions, good resolution is of particular interest, so a 20 mm sup 3 hemispheric crystal was used with a resolution better than 7 keV at 662 keV. This paper presents the experimental device and analyzes the results which show that CdZnTe commercially available detectors enabled us to perform a semi-quantitative determination of the burn-up after a short cooling time. In addition, it is discussed how a burn-up evolution code (CESAR)...

CdZnTe and CdTe materials for X-ray and gamma ray radiation detector applications

International Nuclear Information System (INIS)

Szeles, Csaba

2004-01-01

Good detection efficiency and high energy-resolution make Cadmium Zinc Telluride (CdZnTe) and Cadmium Telluride (CdTe) detectors attractive in many room temperature X-ray and gamma-ray detection applications such as medical and industrial imaging, industrial gauging and non-destructive testing, security and monitoring, nuclear safeguards and non-proliferation, and astrophysics. Advancement of the crystal growth and device fabrication technologies and the reduction of bulk, interface and surface defects in the devices are crucial for the widespread practical deployment of Cd 1-x Zn x Te-based detector technology. Here we review the effects of bulk, interface and surface defects on charge transport, charge transport uniformity and device performance and the progress in the crystal growth and device fabrication technologies aiming at reducing the concentration of harmful defects and improving Cd 1-x Zn x Te detector performance. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Energy dispersive CdTe and CdZnTe detectors for spectral clinical CT and NDT applications

Energy Technology Data Exchange (ETDEWEB)

Barber, W.C., E-mail: william.barber@dxray.com [DxRay, Inc., Northridge, CA (United States); Interon AS, Asker (Norway); Wessel, J.C. [DxRay, Inc., Northridge, CA (United States); Interon AS, Asker (Norway); Nygard, E. [Interon AS, Asker (Norway); Iwanczyk, J.S. [DxRay, Inc., Northridge, CA (United States)

2015-06-01

We are developing room temperature compound semiconductor detectors for applications in energy-resolved high-flux single x-ray photon-counting spectral computed tomography (CT), including functional imaging with nanoparticle contrast agents for medical applications and non-destructive testing (NDT) for security applications. Energy-resolved photon-counting can provide reduced patient dose through optimal energy weighting for a particular imaging task in CT, functional contrast enhancement through spectroscopic imaging of metal nanoparticles in CT, and compositional analysis through multiple basis function material decomposition in CT and NDT. These applications produce high input count rates from an x-ray generator delivered to the detector. Therefore, in order to achieve energy-resolved single photon counting in these applications, a high output count rate (OCR) for an energy-dispersive detector must be achieved at the required spatial resolution and across the required dynamic range for the application. The required performance in terms of the OCR, spatial resolution, and dynamic range must be obtained with sufficient field of view (FOV) for the application thus requiring the tiling of pixel arrays and scanning techniques. Room temperature cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) compound semiconductors, operating as direct conversion x-ray sensors, can provide the required speed when connected to application specific integrated circuits (ASICs) operating at fast peaking times with multiple fixed thresholds per pixel provided the sensors are designed for rapid signal formation across the x-ray energy ranges of the application at the required energy and spatial resolutions, and at a sufficiently high detective quantum efficiency (DQE). We have developed high-flux energy-resolved photon-counting x-ray imaging array sensors using pixellated CdTe and CdZnTe semiconductors optimized for clinical CT and security NDT. We have also fabricated high

Effects of Te inclusions on charge-carrier transport properties in CdZnTe radiation detectors

International Nuclear Information System (INIS)

Gu, Yaxu; Rong, Caicai; Xu, Yadong; Shen, Hao; Zha, Gangqiang; Wang, Ning; Lv, Haoyan; Li, Xinyi; Wei, Dengke; Jie, Wanqi

2015-01-01

Highlights: • This work reveals the behaviors of Te inclusion in affecting charge-carrier transport properties in CdZnTe detectors for the first time and analysis the mechanism therein. • The results show that charge collection efficiencies in Te inclusion degraded regions experience fast ascent under low biases and slow descent at high applied biases, which deviates from the Hecht rule. • This phenomenon is attributed to the competitive influence of two mechanisms under different biases, namely charge carrier trapping due to uniformly distributed point defects and Te inclusion induced transient charge loss. • A modified Hecht equation is further proposed to explain the effects of high-density localized defects, say Te inclusions, on the charge collection efficiency. • We believe that this research has wide appeal to analyze the macroscopic defects and their influence on charge transport properties in semiconductor radiation detectors. - Abstract: The influence of tellurium (Te) inclusions on the charge collection efficiency in cadmium zinc telluride (CdZnTe or CZT) detectors has been investigated using ion beam induced charge (IBIC) technique. Combining the analysis of infrared transmittance image, most of the low charge collection areas in the IBIC images prove the existence of Te inclusions. To further clarify the role of Te inclusions on charge transport properties, bias dependent local IBIC scan was performed on Te inclusion related regions from 20 V to 500 V. The result shows that charge collection efficiencies in Te inclusion degraded regions experience fast ascent under low biases and slow descent at high applied biases, which deviates from Hecht rule. This behavior is attributed to the competitive influence of two mechanisms under different biases, namely charge carrier trapping due to uniformly distributed point defects and Te inclusion induced transient charge loss. A modified Hecht equation is further proposed to explain the effects of high

Performance simulation of an x-ray detector for spectral CT with combined Si and Cd[Zn]Te detection layers.

Science.gov (United States)

Herrmann, Christoph; Engel, Klaus-Jürgen; Wiegert, Jens

2010-12-21

The most obvious problem in obtaining spectral information with energy-resolving photon counting detectors in clinical computed tomography (CT) is the huge x-ray flux present in conventional CT systems. At high tube voltages (e.g. 140 kVp), despite the beam shaper, this flux can be close to 10⁹ Mcps mm⁻² in the direct beam or in regions behind the object, which are close to the direct beam. Without accepting the drawbacks of truncated reconstruction, i.e. estimating missing direct-beam projection data, a photon-counting energy-resolving detector has to be able to deal with such high count rates. Sub-structuring pixels into sub-pixels is not enough to reduce the count rate per pixel to values that today's direct converting Cd[Zn]Te material can cope with (≤ 10 Mcps in an optimistic view). Below 300 µm pixel pitch, x-ray cross-talk (Compton scatter and K-escape) and the effect of charge diffusion between pixels are problematic. By organising the detector in several different layers, the count rate can be further reduced. However this alone does not limit the count rates to the required level, since the high stopping power of the material becomes a disadvantage in the layered approach: a simple absorption calculation for 300 µm pixel pitch shows that the required layer thickness of below 10 Mcps/pixel for the top layers in the direct beam is significantly below 100 µm. In a horizontal multi-layer detector, such thin layers are very difficult to manufacture due to the brittleness of Cd[Zn]Te. In a vertical configuration (also called edge-on illumination (Ludqvist et al 2001 IEEE Trans. Nucl. Sci. 48 1530-6, Roessl et al 2008 IEEE NSS-MIC-RTSD 2008, Conf. Rec. Talk NM2-3)), bonding of the readout electronics (with pixel pitches below 100 µm) is not straightforward although it has already been done successfully (Pellegrini et al 2004 IEEE NSS MIC 2004 pp 2104-9). Obviously, for the top detector layers, materials with lower stopping power would be advantageous

CZT drift strip detectors for high energy astrophysics

DEFF Research Database (Denmark)

Kuvvetli, Irfan; Budtz-Jørgensen, Carl; Caroli, E.

2010-01-01

Requirements for X- and gamma ray detectors for future High Energy Astrophysics missions include high detection efficiency and good energy resolution as well as fine position sensitivity even in three dimensions.We report on experimental investigations on the CZT drift detector developed DTU Space...

Beam test of a large area silicon drift detector

International Nuclear Information System (INIS)

Castoldi, A.; Chinnici, S.; Gatti, E.; Longoni, A.; Palma, F.; Sampietro, M.; Rehak, P.; Ballocchi, G.; Kemmer, J.; Holl, P.; Cox, P.T.; Giacomelli, P.; Vacchi, A.

1992-01-01

The results from the tests of the first large area (4 x 4 cm 2 ) planar silicon drift detector prototype in a pion beam are reported. The measured position resolution in the drift direction is (σ=40 ± 10)μm

The effects of deep level traps on the electrical properties of semi-insulating CdZnTe

Energy Technology Data Exchange (ETDEWEB)

Zha, Gangqiang; Yang, Jian; Xu, Lingyan; Feng, Tao; Wang, Ning; Jie, Wanqi [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an (China)

2014-01-28

Deep level traps have considerable effects on the electrical properties and radiation detection performance of high resistivity CdZnTe. A deep-trap model for high resistivity CdZnTe was proposed in this paper. The high resistivity mechanism and the electrical properties were analyzed based on this model. High resistivity CdZnTe with high trap ionization energy E{sub t} can withstand high bias voltages. The leakage current is dependent on both the deep traps and the shallow impurities. The performance of a CdZnTe radiation detector will deteriorate at low temperatures, and the way in which sub-bandgap light excitation could improve the low temperature performance can be explained using the deep trap model.

Front-end counting mode electronics for CdZnTe sensor readout

CERN Document Server

Moraes, Danielle; Kaplon, Jan

2004-01-01

The development of a front-end circuit optimized for CdZnTe detector readout, implemented in 0.25 mu m CMOS technology, is reported. The ASIC comprises 17 channels of a charge sensitive amplifier with an active feedback, followed by a gain-shaper stage and a discriminator with a 5 bit fine-tune DAC. The signal from the discriminator is sensed by a 25 ns mono-stable circuit and an 18-bit static ripple- counter. The channel architecture is optimized for the detector characteristics in order to achieve the best energy resolution at a maximum counting rate of 2 million counts/second. The amplifier shows a linear sensitivity of 24 mV/fC with 50 ns peaking time and an equivalent noise charge of about 650 e/sup -/, for a detector capacitance of 10 pF. When connected to a 3*3*7 mm/sup 3/ CdZnTe detector the amplifier gain is about 8 mV/keV with a noise around 3.6 keV.

Comparison of the surfaces and interfaces formed for sputter and electroless deposited gold contacts on CdZnTe

Science.gov (United States)

Bell, Steven J.; Baker, Mark A.; Duarte, Diana D.; Schneider, Andreas; Seller, Paul; Sellin, Paul J.; Veale, Matthew C.; Wilson, Matthew D.

2018-01-01

Cadmium zinc telluride (CdZnTe) is a leading sensor material for spectroscopic X/γ-ray imaging in the fields of homeland security, medical imaging, industrial analysis and astrophysics. The metal-semiconductor interface formed during contact deposition is of fundamental importance to the spectroscopic performance of the detector and is primarily determined by the deposition method. A multi-technique analysis of the metal-semiconductor interface formed by sputter and electroless deposition of gold onto (111) aligned CdZnTe is presented. Focused ion beam (FIB) cross section imaging, X-ray photoelectron spectroscopy (XPS) depth profiling and current-voltage (IV) analysis have been applied to determine the structural, chemical and electronic properties of the gold contacts. In a novel approach, principal component analysis has been employed on the XPS depth profiles to extract detailed chemical state information from different depths within the profile. It was found that electroless deposition forms a complicated, graded interface comprised of tellurium oxide, gold/gold telluride particulates, and cadmium chloride. This compared with a sharp transition from surface gold to bulk CdZnTe observed for the interface formed by sputter deposition. The electronic (IV) response for the detector with electroless deposited contacts was symmetric, but was asymmetric for the detector with sputtered gold contacts. This is due to the electroless deposition degrading the difference between the Cd- and Te-faces of the CdZnTe (111) crystal, whilst these differences are maintained for the sputter deposited gold contacts. This work represents an important step in the optimisation of the metal-semiconductor interface which currently is a limiting factor in the development of high resolution CdZnTe detectors.

On the Theory of Compensation in Lithium drifted Semiconductor Detectors

Energy Technology Data Exchange (ETDEWEB)

Lauber, A

1969-04-15

The lithium ion drift method produces detectors with a highly but not perfectly compensated intrinsic region. The amount of fixed space charge left in the depleted layer and its dependence on drift and clean-up parameters is of great practical interest. The imperfect compensation is mainly due to the presence in the depletion layer of thermally generated electron-hole pairs swept apart by the voltage applied to the detector during drift. A theoretical model is developed which takes into account the influence on the fixed space charge of mobile carrier generation and recombination. When recombination of free electrons and holes is negligible the theory predicts the formation of linear space charge gradients. When recombination is strong a constant space charge throughout a large part of the compensated layer may result. The theoretical calculations are compared with experimental findings. The influence of space charge on detector performance is discussed.

Hydrogen high pressure proportional drift detector

International Nuclear Information System (INIS)

Arefiev, A.; Balaev, A.

1983-01-01

The design and operation performances of a proportional drift detector PDD are described. High sensitivity of the applied PAD makes it possible to detect the neutron-proton elastic scattering in the energy range of recoil protons as low as 1 keV. The PDD is filled with hydrogen up to the pressure at 40 bars. High purity of the gas is maintained by a continuously operating purification system. The detector has been operating for several years in a neutron beam at the North Area of the CERN SPS

2-D response mapping of multi-linear silicon drift detectors

International Nuclear Information System (INIS)

Castoldi, A.; Guazzoni, C.; Hartmann, R.; Mezza, D.; Strueder, L.; Tassan Garofolo, F.

2010-01-01

Multi-linear silicon drift detectors (MLSDDs) are good candidates to fulfill simultaneous requirements for 2-D position-sensing and spectroscopy applications. The optimization of their design and performance as 2-D imagers requires a detailed study of timing properties of the charge cloud in the MLSDD architecture. In particular it is important to experimentally determine the dependence of the measured amplitude and time-of-arrival on the photon position of interaction so as to derive the 2D detector response. In this paper we will present a detailed experimental characterization aimed at measuring the detector amplitude response and its timing response. The dependence of charge cloud drift time on precise position of interaction has been measured as a function of detector biasing conditions.

Very high resolution detection of gamma radiation at room-temperature using P-I-N detectors of CdZnTe and HgCdTe

Science.gov (United States)

Hamilton, W. J.; Rhiger, D. R.; Sen, S.; Kalisher, M. H.; James, K.; Reid, C. P.; Gerrish, V.; Baccash, C. O.

1994-08-01

High-energy photon detectors have been constructed by engineering and fabricating p-i-n diode structures consisting of bulk CdZnTe and epitaxial HgCdTe. The p-i-n structure was obtained by liquid-phase epitaxial growth of p and n doped HgCdTe layers on 'intrinsic' CdZnTe material about 1mm thick and approximately 25mm square. Curve tracing shows I-V curves with diode characteristics having resistivity above 1011 Omega -cm and leakage current of less than 400 pA to about - 60V reverse bias on a typical test piece approximately 5 x 8 x 1 mm. Spectra of similar test pieces have been obtained at room temperature with various nuclear isotopic sources over the range of 22 keV to 662 keV which show exceptionally high energy resolution. Resolution as good as 1.82% FWHM was obtained for the 356 keV line of 133Ba with a P/V = 3.4. The performance of these detectors combined with contemporary infrared technology capable of fabricating 2D arrays of these II-VI materials opens up manifold exciting applications in astrophysics, medical, industrial, environmental, and defense spectroscopy and imaging.

Linearity enhancement design of a 16-channel low-noise front-end readout ASIC for CdZnTe detectors

International Nuclear Information System (INIS)

Zeng, Huiming; Wei, Tingcun; Wang, Jia

2017-01-01

A 16-channel front-end readout application-specific integrated circuit (ASIC) with linearity enhancement design for cadmium zinc telluride (CdZnTe) detectors is presented in this paper. The resistors in the slow shaper are realized using a high-Z circuit to obtain constant resistance value instead of using only a metal–oxide–semiconductor (MOS) transistor, thus the shaping time of the slow shaper can be kept constant for different amounts of input energies. As a result, the linearity of conversion gain is improved significantly. The ASIC was designed and fabricated in a 0.35 µm CMOS process with a die size of 2.60 mm×3.53 mm. The tested results show that a typical channel provides an equivalent noise charge (ENC) of 109.7e − +16.3e − /pF with a power consumption of 4 mW and achieves a conversion gain of 87 mV/fC with a nonlinearity of <0.4%. The linearity of conversion gain is improved by at least 86.6% as compared with the traditional approaches using the same front-end readout architecture and manufacture process. Moreover, the inconsistency among channels is <0.3%. An energy resolution of 2.975 keV (FWHM) for gamma rays of 59.5 keV was measured by connecting the ASIC to a 5 mm×5 mm ×2 mm CdZnTe detector at room temperature. The front-end readout ASIC presented in this paper achieves an outstanding linearity performance without compromising the noise, power consumption, and chip size performances.

Linearity enhancement design of a 16-channel low-noise front-end readout ASIC for CdZnTe detectors

Energy Technology Data Exchange (ETDEWEB)

Zeng, Huiming; Wei, Tingcun, E-mail: weitc@nwpu.edu.cn; Wang, Jia

2017-03-01

A 16-channel front-end readout application-specific integrated circuit (ASIC) with linearity enhancement design for cadmium zinc telluride (CdZnTe) detectors is presented in this paper. The resistors in the slow shaper are realized using a high-Z circuit to obtain constant resistance value instead of using only a metal–oxide–semiconductor (MOS) transistor, thus the shaping time of the slow shaper can be kept constant for different amounts of input energies. As a result, the linearity of conversion gain is improved significantly. The ASIC was designed and fabricated in a 0.35 µm CMOS process with a die size of 2.60 mm×3.53 mm. The tested results show that a typical channel provides an equivalent noise charge (ENC) of 109.7e{sup −}+16.3e{sup −}/pF with a power consumption of 4 mW and achieves a conversion gain of 87 mV/fC with a nonlinearity of <0.4%. The linearity of conversion gain is improved by at least 86.6% as compared with the traditional approaches using the same front-end readout architecture and manufacture process. Moreover, the inconsistency among channels is <0.3%. An energy resolution of 2.975 keV (FWHM) for gamma rays of 59.5 keV was measured by connecting the ASIC to a 5 mm×5 mm ×2 mm CdZnTe detector at room temperature. The front-end readout ASIC presented in this paper achieves an outstanding linearity performance without compromising the noise, power consumption, and chip size performances.

Cumulative effects of Te precipitates in CdZnTe radiation detectors

International Nuclear Information System (INIS)

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

2007-01-01

High-quality radiation detector-grade CdZnTe material is free from large-scale defects, such as grain boundaries, twins, and large Te or Cd inclusions (>50 μm), although it usually contains high concentrations of uniformly distributed Te inclusions and precipitates, typically of ∼20-μm-diameter size or smaller. We address the effects of the small-size Te precipitates on charge collection in CZT detectors, the significance of which is not yet well characterized. The strong correlation that we earlier found between the high-resolution X-ray maps and IR images proved that even small Te precipitates can trap substantial fractions of charge from the electron cloud. In this work, we modeled the transport of an electron cloud across idealized CZT devices containing Te precipitates to demonstrate that their cumulative effect can explain the degradation of energy resolution and the detection efficiency losses observed in actual CZT devices. Due to lack of experimental data on how the Te precipitates interact with an electron cloud, we developed a simplified (phenomenological) model based on the geometrical aspects of the problem. Despite its simplicity, the model correctly reproduced many experimental facts and gave quantitative predictions on the extent to which the presence of Te precipitates and inclusions can be tolerated. The broadening of the electron cloud due to repulsion and diffusion is at the core of the problem, making even low concentrations of small precipitates important in the device's performance

High-Rate Performance of Muon Drift Tube Detectors

CERN Document Server

Schwegler, Philipp

The Large Hadron Collider (LHC) at the European Centre for Particle Physics, CERN, collides protons with an unprecedentedly high centre-of-mass energy and luminosity. The collision products are recorded and analysed by four big experiments, one of which is the ATLAS detector. In parallel with the first LHC run from 2009 to 2012, which culminated in the discovery of the last missing particle of the Standard Model of particle physics, the Higgs boson, planning of upgrades of the LHC for higher instantaneous luminosities (HL-LHC) is already progressing. The high instantaneous luminosity of the LHC puts high demands on the detectors with respect to radiation hardness and rate capability which are further increased with the luminosity upgrade. In this thesis, the limitations of the Muon Drift Tube (MDT) chambers of the ATLAS Muon Spectrometer at the high background counting rates at the LHC and performance of new small diameter muon drift tube (sMDT) detectors at the even higher background rates at HL-LHC are stud...

New Position Algorithms for the 3-D CZT Drift Detector

Science.gov (United States)

Budtz-Jørgensen, C.; Kuvvetli, I.

2017-06-01

The 3-D position sensitive CZT detector for high-energy astrophysics developed at DTU has been investigated with a digitizer readout system. The 3-D CZT detector is based on the CZT drift-strip detector principle and was fabricated using a REDLEN CZT crystal (20 mm × 20 mm × 5 mm). The detector contains 12 drift cells, each comprising one collecting anode strip with four drift strips, biased such that the electrons are focused and collected by the anode strips. Three-dimensional position determination is achieved using the anode strip signals, the drift-strip signals, and the signals from ten cathode strips. For the characterization work, we used a DAQ system with a 16 channels 250-MHz 14-b digitizer, SIS3316. It allowed us to analyze the pulse shapes of the signals from four detector cells at a time. The 3-D CZT setup was characterized with a finely collimated radioactive source of 137Cs at 662 keV. The analysis required development of novel position determination algorithms which are the subject of this paper. Using the digitizer readout, we demonstrate improved position determination compared to the previous read out system based on analog electronics. Position resolutions of 0.4-mm full width at half maximum (FWHM) in the x-, y-, and z-directions were achieved and the energy resolution was 7.2-keV FWHM at 662 keV. The timing information allows identification of multiple interaction events within one detector cell, e.g., Compton scattering followed by photoelectric absorption. These characteristics are very important for a high-energy spectral-imager suitable for use in advanced Compton telescopes, or as focal detector for new hard X-ray and soft γ-ray focusing telescopes or in polarimeter instrumentation. CZT detectors are attractive for these applications since they offer relatively high-quantum efficiency. From a technical point of view it is advantageous that their cooling requirements are modest.

True coincidence-summing corrections for the coincident γ-rays measured with coplanar grid CdZnTe detectors

International Nuclear Information System (INIS)

Yuecel, H.; Solmaz, A.N.; Koese, E.; Bor, D.

2010-01-01

In this study, true coincidence-summing (TCS) correction factors have been measured for the sources 22 Na, 60 Co, 133 Ba and 152 Eu by use of three large volume coplanar grid CdZnTe (acronym: CZT) detectors. In case of a close-in detection geometry, two different TCS calculation algorithms were used to compute the required TCS correction factors. Both of the algorithms are based on the measured total-to-peak (TTP) ratio and full-energy peak (FEP) efficiency values that were obtained using almost 'single' energy and coincidence-free nuclides. The results for TCS correction factors obtained by two different algorithms were agreeable to each other. The obtained TCS factors were ranged from about 7% to 30.5% in a 2250 mm 3 CZT detector when a close counting geometry was used. For other two detectors with a volume of 1000 and 1687.5 mm 3 , the resulted TCS correction factors were relatively smaller and varied between about 0.1% and 20% at the close counting geometry condition. Therefore, the results indicate that there is a need for the estimation of TCS corrections in CZT detectors, especially when their crystal volumes are greater than 1 cm 3 and these detectors are used in the case of a close-in detection geometry.

Fast Neutron Detection Using Pixelated CdZnTe Spectrometers

Science.gov (United States)

Streicher, Michael; Goodman, David; Zhu, Yuefeng; Brown, Steven; Kiff, Scott; He, Zhong

2017-07-01

Fast neutrons are an important signature of special nuclear materials (SNMs). They have a low natural background rate and readily penetrate high atomic number materials that easily shield gamma-ray signatures. Therefore, they provide a complementary signal to gamma rays for detecting shielded SNM. Scattering kinematics dictate that a large nucleus (such as Cd or Te) will recoil with small kinetic energy after an elastic collision with a fast neutron. Charge carrier recombination and quenching further reduce the recorded energy deposited. Thus, the energy threshold of CdZnTe detectors must be very low in order to sense the small signals from these recoils. In this paper, the threshold was reduced to less than 5 keVee to demonstrate that the 5.9-keV X-ray line from 55Fe could be separated from electronic noise. Elastic scattering neutron interactions were observed as small energy depositions (less than 20 keVee) using digitally sampled pulse waveforms from pixelated CdZnTe detectors. Characteristic gamma-ray lines from inelastic neutron scattering were also observed.

A drift chamber system for a toroidal detector

International Nuclear Information System (INIS)

Barbosa, F.J.; Christo, S.; Cuevas, C.; Doolittle, G.; Doughty, D.C.; Hutton, C.; Joyce, D.; Mecking, B.A.; Mestayer, M.D.; Niczyporuk, B.; O'Meara, J.E.; Tilles, D.; Tuzel, W.; Yegneswaran, A.

1992-01-01

We present design details for drift chambers to be used in the CLAS detector at CEBAF. Novel features include nonparallel endplates fabricated from composite materials, a gas mixture which includes helium to reduce multiple scattering, low wire tension, and a hexagonal cell layout. Magnetic field strength in the active region ranges from 0 to 2 T, and wire length varies from 10 to 300 cm. We discuss specific construction details for the outer drift chambers. (orig.)

A drift chamber system for a toroidal detector

Energy Technology Data Exchange (ETDEWEB)

Barbosa, F.J.; Christo, S.; Cuevas, C.; Doolittle, G.; Doughty, D.C.; Hutton, C.; Joyce, D.; Mecking, B.A.; Mestayer, M.D.; Niczyporuk, B.; O' Meara, J.E.; Tilles, D.; Tuzel, W.; Yegneswaran, A. (CEBAF, Newport News, VA (United States))

1992-12-01

We present design details for drift chambers to be used in the CLAS detector at CEBAF. Novel features include nonparallel endplates fabricated from composite materials, a gas mixture which includes helium to reduce multiple scattering, low wire tension, and a hexagonal cell layout. Magnetic field strength in the active region ranges from 0 to 2 T, and wire length varies from 10 to 300 cm. We discuss specific construction details for the outer drift chambers. (orig.).

MUON DETECTOR: BARREL DRIFT TUBES (DT) AND ALIGNMENT

CERN Multimedia

Marco Dallavalle

After months of cosmics data taking the drift tube (DT) detector is in good shape, ready for LHC beams. Several hundreds of millions of cosmics events have been recorded; out of those, more than 90% were triggered by the DT system. Data integrity analyses have shown a very reliable read-out system, also during high rate tests. With a 98% of the detector operational, only awaiting the arrival of some low voltage modules and for the completion of the DT Track Finder system, data taking is starting to become routine job. These continuous running exercises have been very useful to study performance and reliability of the detector in a medium term period, allowing understanding and fixing failures that have occurred with low frequency. Drift tubes have become a very stable system, becoming a service of muon triggering for the tracker after its final installation. During the last months, major efforts have taken place in synchronization tasks, within the DT system (250 chambers) and also with the rest of the CMS su...

Drift chamber vertex detectors for SLC/LEP

Energy Technology Data Exchange (ETDEWEB)

Hayes, K G

1988-03-01

Factors influencing the design of drift chamber vertex detectors for SLC and LEP are discussed including global strategy, chamber gas, cell design, and signal processing. The designs of the vertex chambers for the L3 and OPAL experiments at LEP and the Mark II experiment at the SLC are described.

Measurement of 235U Enrichment Using the Semi-Peak-Ratio Technique with CdZnTe Gamma-Ray Detector

International Nuclear Information System (INIS)

Ha, J. H.; Ko, W. I.; Lee, S. Y.; Song, D. Y.; Kim, H. D.; Yang, M. S.

2001-01-01

In uranium enrichment plants and nuclear fuel fabrication facilities, exact measurement of fissile isotope enrichment of Uranium is required for material accounting in international safeguards inspection as well as process quality control. The purpose of this study was to develop a simple measurement system which can portably be used at nuclear fuel fabrication plants especially dealing with low enriched uranium. For this purpose, a small size CZT (CdZnTe) detector was used, and the detector performance in low uranium gamma/X-rays energy range was investigated by use of various enriched uranium oxide samples. New enrichment measurement technique and analysis method for low enriched uranium oxide, so-called, 'semi-peak ratio technique' was developed. The newly developed method was considered as an alternative technique for the low enrichment and would be useful to account nuclear material in safeguarding activity at nuclear fuel fabrication facility

New developments in clinical applications of CdTe and CdZnTe detectors

International Nuclear Information System (INIS)

Scheiber, C.

1996-01-01

This review about the medical applications of CdTe and CdZnTe is an update on the 1992 paper (1992). This new paper is legitimized by the recent progress which has been made in this field. First of all, the usefulness of a new material, i.e. CdZnTe, has been demonstrated. While the two materials are still being improved, it seems as yet too early to debate which of CdTe:Cl or CdZnTe will be the best choice. Historical applications span over the past 18 years, involving devices like miniature probes for per-operative scintigraphy or the monitoring of physiological functions and, closer to us, appliances dedicated to bone densitometry, and have been expanding as such devices have become commercially available, for many years now. Newly available microelectronic circuitry allows 2D-arrays to be built for digital quantitative X-ray (chest, dental..) and for high-resolution gamma cameras. The clinical demand is very high, especially in the field of nuclear medicine. Although there already exist clinical demonstrators, the future of such CdTe applications depends on further reduction in material and device mounting costs. New perspectives concern XCT applications, but the data resulting from research work are kept for restricted use within industrial R and D laboratories. (orig.)

Drift chamber vertex detectors for SLC/LEP

International Nuclear Information System (INIS)

Hayes, K.G.

1987-03-01

The short but measurable lifetimes of the b and c quarks and the tau lepton have motivated the development of high precision tracking detectors capable of providing information on the decay vertex topology of events containing these particles. This paper reviews the OPAL, L3, and MARK II experiments vertex drift chambers

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

Energy Technology Data Exchange (ETDEWEB)

Lauber, A; Malmsten, B

1969-10-15

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

Probe station for testing of ALICE silicon drift detectors

CERN Document Server

Humanic, T J; Piemonte, C; Rashevsky, A; Sugarbaker, E R; Vacchi, A

2003-01-01

Large area, 7.25 cm multiplied by 8.76 cm silicon drift detectors have been developed and are in production for the ALICE experiment at LHC. An active area of the detector of more than 50 cm**2 imposes high demands on the quality of processing and raw material. Automated testing procedures have been developed to test detectors before mounting them on the ladders. Probe stations for ALICE SDD testing were designed and built at INFN, Trieste and Ohio State University (OSU). Testing procedures, detector selection criteria and some details of the OSU probe station design are discussed.

Laboratory and test beam results from a large-area silicon drift detector

CERN Document Server

Bonvicini, V; Giubellino, P; Gregorio, A; Idzik, M; Kolojvari, A A; Montaño-Zetina, L M; Nouais, D; Petta, C; Rashevsky, A; Randazzo, N; Reito, S; Tosello, F; Vacchi, A; Vinogradov, L I; Zampa, N

2000-01-01

A very large-area (6.75*8 cm/sup 2/) silicon drift detector with integrated high-voltage divider has been designed, produced and fully characterised in the laboratory by means of ad hoc designed MOS injection electrodes. The detector is of the "butterfly" type, the sensitive area being subdivided into two regions with a maximum drift length of 3.3 cm. The device was also tested in a pion beam (at the CERN PS) tagged by means of a microstrip detector telescope. Bipolar VLSI front-end cells featuring a noise of 250 e/sup -/ RMS at 0 pF with a slope of 40 e/sup -//pF have been used to read out the signals. The detector showed an excellent stability and featured the expected characteristics. Some preliminary results will be presented. (12 refs).

The properties of the cylindrical drift chambers of the CELLO detector

International Nuclear Information System (INIS)

Binder, U.

1983-12-01

In the present thesis the study of the properties of the cylindrical drift chamber of the CELLO interior detector by muons from the cosmic radiation is described. An iterative procedure for the parametrization of the timepath relation is presented. The numerical approximation obtained by means of this procedure deviated in all ranges of drift time by less than 50 μm from the experimentally determined, nonlinear time-path relation. The chamber properties were determined with and without magnetic fields: With an argon-ethane 50%/50% gas mixture a long plateau of the detection probabilities was reached. Without magnetic field by the drift chambers a mean spatial resolution of 170 μm was obtained. From the dependence of the spatial resolution from the drift path results that the drift chambers respond if the electrons from the first 2 to 3 primary ionizations reach the signal wire. The mean response probability of the drift chambers contributes to 97.5% and the overresponse probability to 3.6%. The mean spatial resolution in the magnetic field was determined by means of the chi 2 -distribution, it contributes to 170 μm. For the response probability the value of 98.3% was determined. The errors in the track parameters were determined by comparison of the cosmic ray tracks in the upper and lower half of the detector. (orig./HSI) [de

Trigger drift chamber for the upgraded mark II detector at PEP

Science.gov (United States)

Ford, W. T.; Smith, J. G.; Wagner, S. R.; Weber, P.; White, S. L.; Alvarez, M.; Calviño, F.; Fernandez, E.

1987-04-01

A small cylindrical track detector was built as an array of single-wire drift cells with aluminized mylar cathode tubes. Point measurement resolution of ˜ 90 μm was achieved with a drift gas of 50% argon-50% ethane at atmospheric pressure. The chamber construction, electronics, and calibration are discussed. Performance results from PEP colliding-beam data are presented.

New developments on silicon drift detectors

International Nuclear Information System (INIS)

Rashevsky, A.

1996-01-01

In the frame of the project to develop large-area linear drift detectors few prototypes have been designed and produced. the function of these prototypes is to allow the evaluation of the solutions chosen for the geometry of the on-board electrodes and the production process. On these prototypes it is studied the static characteristics and measured time of-flight and charge collection injecting charges with an IR laser source. It is report the results from one of the prototypes

Development of Fast High-Resolution Muon Drift-Tube Detectors for High Counting Rates

CERN Document Server

INSPIRE-00287945; Dubbert, J.; Horvat, S.; Kortner, O.; Kroha, H.; Legger, F.; Richter, R.; Adomeit, S.; Biebel, O.; Engl, A.; Hertenberger, R.; Rauscher, F.; Zibell, A.

2011-01-01

Pressurized drift-tube chambers are e?cient detectors for high-precision tracking over large areas. The Monitored Drift-Tube (MDT) chambers of the muon spectrometer of the ATLAS detector at the Large Hadron Collider (LHC) reach a spatial resolution of 35 micons and almost 100% tracking e?ciency with 6 layers of 30 mm diameter drift tubes operated with Ar:CO2 (93:7) gas mixture at 3 bar and a gas gain of 20000. The ATLAS MDT chambers are designed to cope with background counting rates due to neutrons and gamma-rays of up to about 300 kHz per tube which will be exceeded for LHC luminosities larger than the design value of 10-34 per square cm and second. Decreasing the drift-tube diameter to 15 mm while keeping the other parameters, including the gas gain, unchanged reduces the maximum drift time from about 700 ns to 200 ns and the drift-tube occupancy by a factor of 7. New drift-tube chambers for the endcap regions of the ATLAS muon spectrometer have been designed. A prototype chamber consisting of 12 times 8 l...

Monitored Drift Chambers in the ATLAS Detector

CERN Multimedia

Herten, G

Monitored Drift Chambers (MDT) are used in the ATLAS Detector to measure the momentum of high energy muons. They consist of drift tubes, which are filled with an Ar-CO2 gas mixture at 3 bar gas pressure. About 1200 drift chambers are required for ATLAS. They are up to 6 m long. Nevertheless the position of every wire needs to be known with a precision of 20 µm within a chamber. In addition, optical alignment sensors are required to measure the relative position of adjacent chambers with a precision of 30µm. This gigantic task seems impossible at first instance. Indeed it took many years of R&D to invent the right tools and methods before the first chamber could be built according to specifications. Today, at the time when 50% of the chambers have been produced, we are confident that the goal for ATLAS can be reached. The mechanical precision of the chambers could be verified with the x-ray tomograph at CERN. This ingenious device, developed for the MDT system, is able to measure the wire position insid...

Studies of dynamics of electron clouds in STAR silicon drift detectors

CERN Document Server

Bellwied, R; Brandon, N; Caines, H; Chen, W; Dimassimo, D; Dyke, H; Hall, J R; Hardtke, D; Hoffmann, G W; Humanic, T J; Kotova, A I; Kotov, I V; Kraner, H W; Li, Z; Lynn, D; Middelkamp, P; Ott, G; Pandey, S U; Pruneau, C A; Rykov, V L; Schambach, J; Sedlmeir, J; Sugarbaker, E R; Takahashi, J; Wilson, W K

2000-01-01

The dynamics of electrons generated in silicon drift detectors was studied using an IR LED. Electrons were generated at different drift distances. In this way, the evolution of the cloud as a function of drift time was measured. Two methods were used to measure the cloud size. The method of cumulative functions was used to extract the electron cloud profiles. Another method obtains the cloud width from measurements of the charge collected on a single anode as a function of coordinate of the light spot. The evolution of the electron cloud width with drift time is compared with theoretical calculations. Experimental results agreed with theoretical expectations.

Trigger drift chamber for the upgraded Mark II detector at PEP

International Nuclear Information System (INIS)

Ford, W.T.; Smith, J.G.; Wagner, S.R.; Weber, P.; White, S.L.; Alvarez, M.; Calvino, F.; Fernandez, E.; Universidad Autonoma de Barcelona

1987-01-01

A small cylindrical track detector was built as an array of single-wire drift cells with aluminized mylar cathode tubes. Point measurement resolution of ∝90 μm was achieved with a drift gas of 50% argon-50% ethane at atmospheric pressure. The chamber construction, electronics, and calibration are discussed. Performance results from PEP colliding-beam data are presented. (orig.)

Material-specific imaging system using energy-dispersive X-ray diffraction and spatially resolved CdZnTe detectors with potential application in breast imaging

Energy Technology Data Exchange (ETDEWEB)

Barbes, Damien, E-mail: damien.barbes@cea.fr [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Tabary, Joachim, E-mail: joachim.tabary@cea.fr [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Paulus, Caroline, E-mail: caroline.paulus@cea.fr [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Hazemann, Jean-Louis, E-mail: jean-louis.hazemann@neel.cnrs.fr [Univ.Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Verger, Loïck, E-mail: loick.verger@cea.fr [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France)

2017-03-11

This paper presents a coherent X-ray-scattering imaging technique using a multipixel energy-dispersive system. Without any translation, the technique produces specific 1D image from data recorded by a single CdZnTe detector pixel using subpixelation techniques. The method is described in detail, illustrated by a simulation and then experimentally validated. As the main considered application of our study is breast imaging, this validation involves 2D imaging of a phantom made of plastics mimicking breast tissues. The results obtained show that our system can specifically image the phantom using a single detector pixel. For the moment, in vivo breast imaging applications remain difficult, as the dose delivered by the system is too high, but some adjustments are considered for further work.

An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras

Energy Technology Data Exchange (ETDEWEB)

Bolotnikov, A. E., E-mail: bolotnik@bnl.gov; Ackley, K.; Camarda, G. S.; Cherches, C.; Cui, Y.; De Geronimo, G.; Fried, J.; Hossain, A.; Mahler, G.; Maritato, M.; Roy, U.; Salwen, C.; Vernon, E.; Yang, G.; James, R. B. [Brookhaven National Laboratory, Upton, New York 11793 (United States); Hodges, D. [University of Texas at El Paso, El Paso, Texas 79968 (United States); Lee, W. [Korea University, Seoul 136-855 (Korea, Republic of); Petryk, M. [SUNY Binghamton, Vestal, New York 13902 (United States)

2015-07-15

We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm{sup 3} detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays’ performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

Analysis of Etched CdZnTe Substrates

Science.gov (United States)

Benson, J. D.; Bubulac, L. O.; Jaime-Vasquez, M.; Lennon, C. M.; Arias, J. M.; Smith, P. J.; Jacobs, R. N.; Markunas, J. K.; Almeida, L. A.; Stoltz, A.; Wijewarnasuriya, P. S.; Peterson, J.; Reddy, M.; Jones, K.; Johnson, S. M.; Lofgreen, D. D.

2016-09-01

State-of-the-art as-received (112)B CdZnTe substrates have been examined for surface impurity contamination and polishing residue. Two 4 cm × 4 cm and one 6 cm × 6 cm (112)B state-of-the-art as-received CdZnTe wafers were analyzed. A maximum surface impurity concentration of Al = 1.7 × 1015 atoms cm-2, Si = 3.7 × 1013 atoms cm-2, Cl = 3.12 × 1015 atoms cm-2, S = 1.7 × 1014 atoms cm-2, P = 1.1 × 1014 atoms cm-2, Fe = 1.0 × 1013 atoms cm-2, Br = 1.2 × 1014 atoms cm-2, and Cu = 4 × 1012 atoms cm-2 was observed on the as-received CdZnTe wafers. CdZnTe particulates and residual SiO2 polishing grit were observed on the surface of the as-received (112)B CdZnTe substrates. The polishing grit/CdZnTe particulate density on CdZnTe wafers was observed to vary across a 6 cm × 6 cm wafer from ˜4 × 107 cm-2 to 2.5 × 108 cm-2. The surface impurity and damage layer of the (112)B CdZnTe wafers dictate that a molecular beam epitaxy (MBE) preparation etch is required. The contamination for one 4 cm × 4 cm and one 6 cm × 6 cm CdZnTe wafer after a standard MBE Br:methanol preparation etch procedure was also analyzed. A maximum surface impurity concentration of Al = 2.4 × 1015 atoms cm-2, Si = 4.0 × 1013 atoms cm-2, Cl = 7.5 × 1013 atoms cm-2, S = 4.4 × 1013 atoms cm-2, P = 9.8 × 1013 atoms cm-2, Fe = 1.0 × 1013 atoms cm-2, Br = 2.9 × 1014 atoms cm-2, and Cu = 5.2 × 1012 atoms cm-2 was observed on the MBE preparation-etched CdZnTe wafers. The MBE preparation-etched surface contamination consists of Cd(Zn)Te particles/flakes. No residual SiO2 polishing grit was observed on the (112)B surface.

Test beam results of Silicon Drift Detector prototypes for the ALICE experiment

Energy Technology Data Exchange (ETDEWEB)

Nouais, D.; Bonvicini, V.; Busso, L.; Cerello, P.; Giubellino, P.; Gregorio, A.; Hernandez-Montoya, R.; Idzik, M.; Kolojvari, A.; Mazza, G.; Montano, L. M.; Nilsen, B.S.; Petta, C.; Randazzo, N.; Rashevsky, A.; Reito, S.; Rivetti, A.; Tosello, F.; Trzaska, W.H.; Vacchi, A

1999-08-01

We report preliminary beam test results of linear Silicon Drift Detector prototypes for the ALICE experiment. Linearity, resolution, charge transport and collection, and efficiency have been studied using a minimum ionizing particle beam for a very large area detector prototype read out with the OLA preamplifier/shaper and for another detector read out using a new transimpedance amplifier with a non linear response.

Construction of a full-length prototype of the BESIII drift chamber and on-detector test for the BESIII drift chamber electronics

International Nuclear Information System (INIS)

Qin Zhonghua; Wu Linghui; Liu Jianbei; Chinese Academy of Sciences, Beijing; Yan Zhikang; Hunan Univ., Changsha; Chen Yuanbo; Chen Chang; Xu Meihang; Wang Lan; Ma Xiaoyan; Jin Yan; Liu Rongguang; Tang Xiao; Zhang Guifang; Zhu Qiming; Sheng Huayi; Zhu Kejun

2007-01-01

A full-length prototype of the BESIII drift chamber was built. The experience gained on gas sealing, high voltage supply and front-end electronics installation should be greatly beneficial to the successful construction of the BESIII drift chamber. An on-detector test of the BESIII drift chamber electronics was carried out with the constructed prototype chamber. The noise performance, drift time and charge measurements, and electronics gains were examined specifically. The final test results indicate that the electronics have a good performance and can satisfy their design requirements. (authors)

Point Defect Properties of Cd(Zn)Te and TlBr for Room-Temperature Gamma Radiation Detectors

Science.gov (United States)

Lordi, Vincenzo

2013-03-01

The effects of various crystal defects in CdTe, Cd1-xZnxTe (CZT), and TlBr are critical for their performance as room-temperature gamma radiation detectors. We use predictive first principles theoretical methods to provide fundamental, atomic scale understanding of the defect properties of these materials to enable design of optimal growth and processing conditions, such as doping, annealing, and stoichiometry. Several recent cases will be reviewed, including (i) accurate calculations of the thermodynamic and electronic properties of native point defects and point defect complexes in CdTe and CZT; (ii) the effects of Zn alloying on the native point defect properties of CZT; (iii) point defect diffusion and binding related to Te clustering in Cd(Zn)Te; (iv) the profound effect of native point defects--principally vacancies--on the intrinsic material properties of TlBr, particularly electronic and ionic conductivity; (v) tailored doping of TlBr to independently control the electronic and ionic conductivity; and (vi) the effects of metal impurities on the electronic properties and device performance of TlBr detectors. Prepared by LLNL under Contract DE-AC52-07NA27344 with support from the National Nuclear Security Administration Office of Nonproliferation and Verification Research and Development NA-22.

Correlation of point defects in CdZnTe with charge transport:application to room-temperature x-ray and gamma-ray. Final Technical Report

International Nuclear Information System (INIS)

Giles, Nancy C.

2003-01-01

The primary goal of this project has been to characterize and identify point defects in CdZnTe. There are two experimental focus areas: (1) photoluminescence and EPR. Results are compared with radiation detector performance. Applications requiring room-temperature x-ray and gamma-ray detectors are rapidly increasing and now include nuclear medicine, space sciences, national security, environmental remediation, nonproliferation inspections, etc. To meet these needs, a new generation of detectors based on single crystals of cadmium zinc telluride (Cd 1-x Zn x Te) is being developed. This semiconductor material possesses many desirable detector properties, such as constituent atoms with high atomic number (Z), a sufficiently large band gap to minimize leakage currents at room temperature, and high intrinsic mobility-lifetime (p) products for electrons and holes. However, despite the tremendous promise of this material, problems clearly exist. CdZnTe crystals are difficult to grow in large sizes and with ultra-high purity. There is a need to further lower the leakage currents in detector-grade material and also to increase the efficiency of charge collection. In general, all aspects of carrier trapping in this material must be understood and minimized. Point defects are a primary reason CdZnTe crystals have not yet reached their expected levels of performance. Thus, a better understanding of the role of point defects and the larger microstructure defects on the transport of electrons and holes will lead to improved detector-grade CdZnTe. The primary goal of this project has been to characterize and identify point defects (e.g., impurities, vacancies, vacancy-impurity complexes, etc.) in CdZnTe and determine the mechanisms by which these defects influence the carrier μτ products. Special attention is given to the role of shallow donors, shallow acceptors, and deeper acceptors. There are two experimental focus areas in the project: (1) liquid-helium photoluminescence

SILICON DRIFT DETECTORS FOR THE STAR/SVT EXPERIMENT AT RHIC

International Nuclear Information System (INIS)

TAKAHASHI, J.

1998-01-01

Large area linear Silicon Drift Detectors (SDD) were developed to be used in the Silicon Vertex Tracker (SVT) of the STAR experiment at the BNL relativistic heavy ion collider (RHIC). The SDD is in its final design and has been submitted for large scale production. Test results show that the detector exhibits excellent position resolution and low noise. A special characterization procedure was developed to test detector wafers in order to select good detectors for the SVT. Recently, 15 STAR/SVT SDD's were assembled as a tracking device in a BNL-AGS heavy ion experiment (E896). It is the first tracking application of these detectors and their corresponding front-end electronics in an experimental environment. Preliminary results indicating good detector performance are shown and discussed in this paper

Test beam results of silicon drift detector prototypes for the ALICE experiment

CERN Document Server

Nouais, D; Busso, L; Cerello, P G; Giubellino, P; Gregorio, A; Hernández-Montoya, R; Idzik, M; Kolojvari, A A; Mazza, G; Montaño-Zetina, L M; Nilsson, B S; Petta, C; Randazzo, N; Rashevsky, A; Reito, S; Rivetti, A; Tosello, F; Trzaska, W H; Vacchi, A

1999-01-01

We report preliminary beam test results of linear silicon drift detector prototypes for the ALICE experiment. Linearity, resolution, charge transport and collection, and efficiency have been studied using a minimum ionizing particle beam for a very large area detector prototype read out with the OLA preamplifier/shaper and for another detector read out using a new transimpedance amplifier with a nonlinear response. (14 refs).

Large area silicon drift detectors for x-rays -- New results

International Nuclear Information System (INIS)

Iwanczyk, J.S.; Patt, B.E.; Tull, C.R.; Segal, J.D.; Kenney, C.J.; Hedman, B.; Hodgson, K.O.

1998-01-01

Large area silicon drift detectors, consisting of 8 mm and 12 mm diameter hexagons, were fabricated on 0.35 mm thick high resistivity n-type silicon. An external FET and a low-noise charge sensitive preamplifier were used for testing the prototype detectors. The detector performance was measured in the range 75 to 25 C using Peltier cooling, and from 0.125 to 6 micros amplifier shaping time. Measured energy resolutions were 159 eV FWHM and 263 eV FWHM for the 0.5 cm 2 and 1 cm 2 detectors, respectively (at 5.9 keV, -75 C, 6 micros shaping time). The uniformity of the detector response over the entire active area (measured using 560 nm light) was < 0.5%

Charge collection in the Silicon Drift Detectors of the ALICE experiment

CERN Document Server

Alessandro, B; Batigne, G; Beolé, S; Biolcati, E; Cerello, P; Coli, S; Corrales Morales, Y; Crescio, E; De Remigis, P; Falchieri, D; Giraudo, G; Giubellino, P; Lea, R; Marzari Chiesa, A; Masera, M; Mazza, G; Ortona, G; Prino, F; Ramello, L; Rashevsky, A; Riccati, L; Rivetti, A; Senyukov, S; Siciliano, M; Sitta, M; Subieta, M; Toscano, L; Tosello, F

2010-01-01

A detailed study of charge collection efficiency has been performed on the Silicon Drift Detectors (SDD) of the ALICE experiment. Three different methods to study the collected charge as a function of the drift time have been implemented. The first approach consists in measuring the charge at different injection distances moving an infrared laser by means of micrometric step motors. The second method is based on the measurement of the charge injected by the laser at fixed drift distance and varying the drift field, thus changing the drift time. In the last method, the measurement of the charge deposited by atmospheric muons is used to study the charge collection efficiency as a function of the drift time. The three methods gave consistent results and indicated that no charge loss during the drift is observed for the sensor types used in 99% of the SDD modules mounted on the ALICE Inner Tracking System. The atmospheric muons have also been used to test the effect of the zero-suppression applied to reduce the d...

Exploration of Pixelated detectors for double beta decay searches within the COBRA experiment

Energy Technology Data Exchange (ETDEWEB)

Schwenke, M., E-mail: schwenke@asp.tu-dresden.de [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, Zellescher Weg 19, 01069 Dresden (Germany); Zuber, K.; Janutta, B. [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, Zellescher Weg 19, 01069 Dresden (Germany); He, Z.; Zeng, F. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109-2104 (United States); Anton, G.; Michel, T.; Durst, J.; Lueck, F.; Gleixner, T. [Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany); Goessling, C.; Schulz, O.; Koettig, T. [Technische Universitaet Dortmund, Physik E IV, 44221 Dortmund (Germany); Krawczynski, H.; Martin, J. [Department of Physics, Washington University in St. Louis, Campus Box 1105, One Brookings Drive, St. Louis, MO 63130-4899 (United States); Stekl, I.; Cermak, P. [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, 128 00 Prague (Czech Republic)

2011-09-11

The aim of the COBRA experiment is the search for neutrinoless double beta decay events in Cadmium Zinc Telluride (CdZnTe) room temperature semiconductor detectors. The development of pixelated detectors provides the potential for clear event identification and thus major background reduction. The tracking option of a semiconductor is a unique approach in this field. For initial studies, several possible detector systems are considered with a special regard for low background applications: the large volume system Polaris with a pixelated CdZnTe sensor, Timepix detectors with Si and enriched CdTe sensor material and a CdZnTe pixel system developed at the Washington University in St. Louis, USA. For all detector systems first experimental background measurements taken at underground laboratories (Gran Sasso Underground Laboratory in Italy, LNGS and the Niederniveau Messlabor Felsenkeller in Dresden, Germany) and additionally for the Timepix detectors simulation results are presented.

The X-ray sensitivity of semi-insulating polycrystalline CdZnTe thick films

International Nuclear Information System (INIS)

Won, Jae Ho; Kim, Ki Hyun; Suh, Jong Hee; Cho, Shin Hang; Cho, Pyong Kon; Hong, Jin Ki; Kim, Sun Ung

2008-01-01

The X-ray sensitivity is one of the important parameters indicating the detector performance. The X-ray sensitivity of semi-insulating polycrystalline CdZnTe:Cl thick films was investigated as a function of electric field, mean photon energy, film thickness, and charge carrier transport parameters and, compared with another promising detector materials. The X-ray sensitivities of the polycrystalline CdZnTe films with 350 μm thickness were about 2.2 and 6.2 μC/cm 2 /R in the ohmic-type and Schottky-type detector at 0.83 V/μm, respectively

The CdZnTe Detector with Slit Collimator for Measure Distribution of the Specific Activity Radionuclide in the Ground

Science.gov (United States)

Stepanov, V. E.; Volkovich, A. G.; Potapov, V. N.; Semin, I. A.; Stepanov, A. V.; Simirskii, Iu. N.

2018-01-01

From 2011 in the NRC "Kurchatov Institute" carry out the dismantling of the MR multiloop research reactor. Now the reactor and all technological equipment in the premises of the reactor were dismantled. Now the measurements of radioactive contamination in the reactor premises are made. The most contaminated parts of premises - floor and the ground beneath it. To measure the distribution of specific activity in the ground the CdZnTe detector (volume 500MM3) was used. Detector placed in a lead shielding with a slit collimation hole. The upper part of shielding is made movable to close and open the slit of the collimator. At each point two measurements carried out: with open and closed collimator. The software for determination specific activity of radionuclides in ground was developed. The mathematical model of spectrometric system based on the Monte-Carlo method. Measurements of specific activity of ground were made. Using the results of measurements the thickness of the removed layer of ground and the amount of radioactive waste were calculated.

A novel self-biased linear silicon drift detector

International Nuclear Information System (INIS)

Corsi, F.; Gramegna, G.; Marzocca, C.

1999-01-01

A novel linear silicon drift detector (SDD) is proposed in which the proper potential profile is established by the voltage drop along a unique p + cathode implanted across the surfaces. This p + implant, arranged in a zigzag shape, acts at the same time as voltage divider and field cathode and allows one to increase the sensitive area, improving also the uniformity of the thermal distribution and thus minimizing the fluctuation of the electron mobility on the sensitive zone of the SDD. The perturbations of the drift field due to the asymmetry of the strips constituting the zigzag cathode have been evaluated by solving analytically Poisson's equation for a simplified model of the structure. Three-dimensional numerical simulations have been carried out to prove the negligible amount of the perturbation and the effectiveness of the proposed structure. Based on this principle, a prototype has been manufactured at Canberra Semiconductor Company. Dynamic measurements of the time-of-flight of an injected charge prove that the linearity of the prototype and the drift uniformity in the anode direction are very high

Performance of the Charge Injectors of the ALICE Silicon Drift Detectors

Czech Academy of Sciences Publication Activity Database

Kushpil, Svetlana

2012-01-01

Roč. 37, č. 37 (2012), s. 970-975 ISSN 1875-3892. [TIPP 2011 - Technology and Instrumentation in Particle Physics 2011. Chicago, 09.06.2011-14.06.2011] R&D Projects: GA MŠk LA08015 Institutional support: RVO:61389005 Keywords : semiconductor detector * silicon drift detector * MOS charge injector Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders http://www.sciencedirect.com/science/article/pii/S1875389212017920

High-rate performance of muon drift tube detectors

International Nuclear Information System (INIS)

Schwegler, Philipp

2014-01-01

The Large Hadron Collider (LHC) at the European Centre for Particle Physics, CERN, collides protons with an unprecedentedly high centre-of-mass energy and luminosity. The collision products are recorded and analysed by four big experiments, one of which is the ATLAS detector. In parallel with the first LHC run from 2009 to 2012, which culminated in the discovery of the last missing particle of the Standard Model of particle physics, the Higgs boson, planning of upgrades of the LHC for higher instantaneous luminosities (HL-LHC) is already progressing. The high instantaneous luminosity of the LHC puts high demands on the detectors with respect to radiation hardness and rate capability which are further increased with the luminosity upgrade. In this thesis, the limitations of the Muon Drift Tube (MDT) chambers of the ATLAS Muon Spectrometer at the high background counting rates at the LHC and performance of new small diameter muon drift tube (sMDT) detectors at the even higher background rates at HL-LHC are studied. The resolution and efficiency of sMDT chambers at high γ-ray and proton irradiation rates well beyond the ones expected at HL-LHC have been measured and the irradiation effects understood using detailed simulations. The sMDT chambers offer an about an order of magnitude better rate capability and are an ideal replacement for the MDT chambers because of compatibility of services and read-out. The limitations of the sMDT chambers are now in the read-out electronics, taken from the MDT chambers, to which improvements for even higher rate capability are proposed.

New Position Algorithms for the 3-D CZT Drift Detector

DEFF Research Database (Denmark)

Budtz-Jørgensen, Carl; Kuvvetli, Irfan

2017-01-01

The 3-D position sensitive CZT detector for high-energy astrophysics developed at DTU has been investigated with a digitizer readout system. The 3-D CZT detector is based on the CZT drift-strip detector principle and was fabricated using a REDLEN CZT crystal (20 mm x 20 mm x 5 mm). The detector...... at 662 keV. The analysis required development of novel position determination algorithms which are the subject of this paper. Using the digitizer readout, we demonstrate improved position determination compared to the previous read out system based on analog electronics. Position resolutions of 0.4-mm....... These characteristics are very important for a high-energy spectral-imager suitable for use in advanced Compton telescopes, or as focal detector for new hard X-ray and soft gamma-ray focusing telescopes or in polarimeter instrumentation. CZT detectors are attractive for these applications since they offer relatively...

Silicon drift detectors coupled to CsI(Tl) scintillators for spaceborne gamma-ray detectors

International Nuclear Information System (INIS)

Marisaldi, M.; Fiorini, C.; Labanti, C.; Longoni, A.; Perotti, F.; Rossi, E.; Soltau, H.

2006-01-01

Silicon Drift Detectors (SDDs), thanks to their peculiar low noise characteristics, have proven to be excellent photodetectors for CsI(Tl) scintillation light detection. Two basic detector configurations have been developed: either a single SDD or a monolithic array of SDDs coupled to a single CsI(Tl) crystal. A 16 independent detectors prototype is under construction, designed to work in conjunction with the MEGA Compton telescope prototype under development at MPE, Garching, Germany. A single SDD coupled to a CsI(Tl) crystal has also been tested as a monolithic detector with an extended energy range between 1.5 keV and 1 MeV. The SDD is used as a direct X-ray detector for low energy photons interacting in silicon and as a scintillation light photodetector for photons interacting in the crystal. The type of interaction is identified by means of pulse shape discrimination technique. Detectors based on an array of SDDs coupled to a single CsI(Tl) crystal have also been built. The readout of these detectors is based on the Anger camera technique, and submillimeter spatial resolution can be achieved. The two detectors' approaches and their applications will be described

Development of electron temperature measuring system by silicon drift detector

International Nuclear Information System (INIS)

Song Xianying; Yang Jinwei; Liao Min

2007-12-01

Soft X-ray spectroscopy with two channels Silicon Drift Detector (SDD) are adopted for electron temperature measuring on HL-2A tokamak in 2005. The working principle, design and first operation of the SDD soft X-ray spectroscopy are introduced. The measuring results of electron temperature are also presented. The results show that the SDD is very good detector for electron temperature measuring on HL-2A tokamak. These will become a solid basic work to establish SDD array for electron temperature profiling. (authors)

ADVANCED READOUT ELECTRONICS FOR MULTIELEMENT CdZnTe SENSORS

International Nuclear Information System (INIS)

DE GERONIMO, G.; O CONNOR, P.; KANDASAMY, A.; GROSHOLZ, J.

2002-01-01

A generation of high performance front-end and read-out ASICs customized for highly segmented CdZnTe sensors is presented. The ASICs, developed in a multi-year effort at Brookhaven National Laboratory, are targeted to a wide range of applications including medical, safeguards/security, industrial, research, and spectroscopy. The front-end multichannel ASICs provide high accuracy low noise preamplification and filtering of signals, with versions for small and large area CdZnTe elements. They implement a high order unipolar or bipolar shaper, an innovative low noise continuous reset system with self-adapting capability to the wide range of detector leakage currents, a new system for stabilizing the output baseline and high output driving capability. The general-purpose versions include programmable gain and peaking time. The read-out multichannel ASICs provide fully data driven high accuracy amplitude and time measurements, multiplexing and time domain derandomization of the shaped pulses. They implement a fast arbitration scheme and an array of innovative two-phase offset-free rail-to-rail analog peak detectors for buffering and absorption of input rate fluctuations, thus greatly relaxing the rate requirement on the external ADC. Pulse amplitude, hit timing, pulse risetime, and channel address per processed pulse are available at the output in correspondence of an external readout request. Prototype chips have been fabricated in 0.5 and 0.35 (micro)m CMOS and tested. Design concepts and experimental results are discussed

Beam test results of the irradiated Silicon Drift Detector for ALICE

OpenAIRE

Kushpil, S.; Crescio, E.; Giubellino, P.; Idzik, M.; Kolozhvari, A.; Kushpil, V.; Martinez, M. I.; Mazza, G.; Mazzoni, A.; Meddi, F.; Nouais, D.; Petracek, V.; Piemonte, C.; Rashevsky, A.; Riccati, L.

2005-01-01

The Silicon Drift Detectors will equip two of the six cylindrical layers of high precision position sensitive detectors in the ITS of the ALICE experiment at LHC. In this paper we report the beam test results of a SDD irradiated with 1 GeV electrons. The aim of this test was to verify the radiation tolerance of the device under an electron fluence equivalent to twice particle fluence expected during 10 years of ALICE operation.

Long-drift calorimeter modules for the Soudan 2 nucleon decay detector

International Nuclear Information System (INIS)

Hoftiezer, J.

1985-01-01

The first full size 5-ton detector modules for the Soudan 2 nucleon decay experiment have been assembled and operated. Modules consist of a hexagonal array of drift tubes and corrugated steel, instrumented to read out three-dimensional track positions and pulse height. These will be assembled to form an isotropic, continuously sensitive, self-triggering detector. Details of the design, construction, operation and performance of the modules are discussed. 7 refs., 10 figs

LIGHT INDUCED TELLURIUM ENRICHMENT ON CDZNTE CRYSTAL SURFACES DETECTED BY RAMAN SPECTROSCOPY

International Nuclear Information System (INIS)

Hawkins, S; Eliel Villa-Aleman, E; Martine Duff, M; Douglas Hunter, D

2007-01-01

Synthetic CdZnTe or 'CZT' crystals can be grown under controlled conditions to produce high quality crystals to be used as room temperature radiation detectors. Even the best crystal growth methods result in defects, such as tellurium secondary phases, that affect the crystal's performance. In this study, CZT crystals were analyzed by micro Raman spectroscopy. The growth of Te rich areas on the surface was induced by low powered lasers. The growth was observed versus time with low power Raman scattering and was observed immediately under higher power conditions. The detector response was also measured after induced Te enrichment

Design and tests of the z-coordinate drift chamber system for the OPAL central detector at LEP

International Nuclear Information System (INIS)

Mes, H.; Dixit, M.S.; Godfrey, L.; Hanna, D.; Hargrove, C.K.; Losty, M.J.; Oakham, F.G.; Bavaria, G.; Jeremie, H.; Lessard, L.; Lorazo, B.; Martin, J.P.

1988-01-01

A system of drift chambers has been designed to make high resolution measurements of the z-coordinates of charged tracks at the outer radius of the OPAL central detector at LEP. The unit module of this detector is a 25 cm drift length bidirectional cell with six sense wires in a thin 50 cm wide by 29 mm high drift slot. Tests indicate that the chamber has a wide and stable electric field operating range and its performance is unaffected by small misalignments between the drift electric field and an external magnetic field. The drift cell was found to have uniform acceptance up to its geometrical boundaries, and the z-resolution for beam tracks normal to the chamber was measured to be in the range of 40-175 μm. (orig.)

Charge collection and depth sensing investigation on CZT drift strip detectors

DEFF Research Database (Denmark)

Kuvvetli, Irfan; Budtz-Jørgensen, Carl; Caroli, E.

2010-01-01

CZT drift strip detectors with Planar Transverse Field (PTF) configuration are suitable for high energy astrophysics instrumentation, where high efficiency, high energy and position resolution are required from the sensors. We report on experimental investigations on the DTU Space developed CZT d...

IDeF-X ECLAIRs: A CMOS ASIC for the Readout of CdTe and CdZnTe Detectors for High Resolution Spectroscopy

International Nuclear Information System (INIS)

Gevin, O.; Baron, P.; Coppolani, X.; Delagnes, E.; Lugiez, F.; Daly, F.; Limousin, O.; Meuris, A.; Pinsard, F.; Renaud, D.

2009-01-01

The very last member of the IDeF-X ASIC family is presented: IDeF-X ECLAIRs is a 32-channel front end ASIC designed for the readout of Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CdZnTe) Detectors. Thanks to its noise performance (Equivalent Noise Charge floor of 33 e - rms) and to its radiation hardened design (Single Event Latch-up Linear Energy Transfer threshold of 56 MeV.cm 2 .mg -1 ), the chip is well suited for soft X-rays energy discrimination and high energy resolution, 'space proof', hard X-ray spectroscopy. We measured an energy low threshold of less than 4 keV with a 10 pF input capacitor and a minimal reachable sensitivity of the Equivalent Noise Charge (ENC) to input capacitance of less than 7e - /pF obtained with a 6 μs peak time. IDeF-X ECLAIRs will be used for the readout of 6400 CdTe Schottky mono-pixel detectors of the 2D coded mask imaging telescope ECLAIRs aboard the SVOM satellite. IDeF-X ECLAIRs (or IDeF-X V2) has also been designed for the readout of a pixelated CdTe detector in the miniature spectro-imager prototype Caliste 256 that is currently foreseen for the high energy detector module of the Simbol-X mission. (authors)

IDeF-X ECLAIRs: A CMOS ASIC for the Readout of CdTe and CdZnTe Detectors for High Resolution Spectroscopy

Science.gov (United States)

Gevin, Olivier; Baron, Pascal; Coppolani, Xavier; Daly, FranÇois; Delagnes, Eric; Limousin, Olivier; Lugiez, Francis; Meuris, Aline; Pinsard, FrÉdÉric; Renaud, Diana

2009-08-01

The very last member of the IDeF-X ASIC family is presented: IDeF-X ECLAIRs is a 32-channel front end ASIC designed for the readout of Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CdZnTe) Detectors. Thanks to its noise performance (Equivalent Noise Charge floor of 33 e- rms) and to its radiation hardened design (Single Event Latchup Linear Energy Transfer threshold of 56 MeV.cm2.mg-1), the chip is well suited for soft X-rays energy discrimination and high energy resolution, ldquospace proof,rdquo hard X-ray spectroscopy. We measured an energy low threshold of less than 4 keV with a 10 pF input capacitor and a minimal reachable sensitivity of the Equivalent Noise Charge (ENC) to input capacitance of less than 7 e-/pF obtained with a 6 mus peak time. IDeF-X ECLAIRs will be used for the readout of 6400 CdTe Schottky monopixel detectors of the 2D coded mask imaging telescope ECLAIRs aboard the SVOM satellite. IDeF-X ECLAIRs (or IDeF-X V2) has also been designed for the readout of a pixelated CdTe detector in the miniature spectro-imager prototype Caliste 256 that is currently foreseen for the high energy detector module of the Simbol-X mission.

Calibration and performance of the MARK II drift chamber vertex detector

International Nuclear Information System (INIS)

Durrett, D.; Ford, W.T.; Hinshaw, D.A.; Rankin, P.; Smith, J.G.; Weber, P.

1990-05-01

We have calibrated and studied the performance of the MARK II drift chamber vertex detector with cosmic ray tracks collected with the chamber inside the MARK II detector at the SLC. The chamber achieves 30 μm impact parameter resolution and 500 μm track-pair resolution using CO 2 /C 2 H 6 H 6 (92/8) at 2 atmospheres pressure. The chamber has successfully recorded Z 0 decays at the SLC, and resolved tracks in dense hadronic jets with good efficiency and high accuracy. 5 refs., 13 figs

Knock-on electrons in WA98 silicon drift detector

International Nuclear Information System (INIS)

Eliseev, S.

1997-01-01

Silicon Drift Detector is used to estimate production of knock-on electrons created by passage of 158 GeV /u fully stripped Pb ion through thick lead target. Analysed data were collected in 1995 during Pb+Pb run in WA98 heavy ion experiment at CERN SPS. Information from WA98 Cherenkov beam counter makes it possible to classify events according to number of additional Pb ions which have during detector's read-out time passed through the target without nuclear interaction. Events with one and none pile-up ion are used for statistical separation of knock-on electrons from all detected charged particles. Resulting inclusive spectra of knock-on electrons are compared with GRANT simulations and good agreement is found. (author)

A liquid-nitrogen monitor for lithium-drifted germanium detectors

International Nuclear Information System (INIS)

Andeweg, A.H.

1977-11-01

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

Light-Induced Tellurium Enrichment on CdZnTe Crystal Surfaces Detected by Raman Spectroscopy

International Nuclear Information System (INIS)

Hawkins, Samantha A.; Villa-Aleman, Eliel; Duff, Martine C.; Hunter, Doug B.; Burger, Arnold; Groza, Michael; Buliga, Vladimir; Black, David R.

2008-01-01

CdZnTe (CZT) crystals can be grown under controlled conditions to produce high-quality crystals to be used as room-temperature radiation detectors. Even the best crystal growth methods result in defects, such as tellurium secondary phases, that affect the crystal's performance. In this study, CZT crystals were analyzed by micro-Raman spectroscopy. The growth of Te rich areas on the surface was induced by low-power lasers. The growth was observed versus time with low-power Raman scattering and was observed immediately under higher-power conditions. The detector response was also measured after induced Te enrichment.

XA readout chip characteristics and CdZnTe spectral measurements

International Nuclear Information System (INIS)

Barbier, L.M.; Birsa, F.; Odom, J.

1999-01-01

The authors report on the performance of a CdZnTe (CZT) array readout by an XA (X-ray imaging chip produced at the AMS foundry) application specific readout chip (ASIC). The array was designed and fabricated at NASA/Goddard Space Flight Center (GSFC) as a prototype for the Burst Arc-Second Imaging and Spectroscopy gamma-ray instrument. The XA ASIC was obtained from Integrated Detector and Electronics (IDE), in Norway. Performance characteristics and spectral data for 241 Am are presented both at room temperature and at -20 C. The measured noise (σ) was 2.5 keV at 60 keV at room temperature. This paper represents a progress report on work with the XA ASIC and CZT detectors. Work is continuing and in particular, larger arrays are planned for future NASA missions

SOI detector with drift field due to majority carrier flow - an alternative to biasing in depletion

Energy Technology Data Exchange (ETDEWEB)

Trimpl, M.; Deptuch, G.; Yarema, R.; /Fermilab

2010-11-01

This paper reports on a SOI detector with drift field induced by the flow of majority carriers. It is proposed as an alternative method of detector biasing compared to standard depletion. N-drift rings in n-substrate are used at the front side of the detector to provide charge collecting field in depth as well as to improve the lateral charge collection. The concept was verified on a 2.5 x 2.5 mm{sup 2} large detector array with 20 {micro}m and 40 {micro}m pixel pitch fabricated in August 2009 using the OKI semiconductor process. First results, obtained with a radioactive source to demonstrate spatial resolution and spectroscopic performance of the detector for the two different pixel sizes will be shown and compared to results obtained with a standard depletion scheme. Two different diode designs, one using a standard p-implantation and one surrounded by an additional BPW implant will be compared as well.

The influence of anisotropic electron drift velocity on the signal shapes of closed-end HPGe detectors

CERN Document Server

Mihailescu, L; Lieder, R M; Brands, H; Jaeger, H

2000-01-01

This study is concerned with the anisotropy of the electron drift velocity in germanium crystals at high electric fields and low temperature, and its influence on the charge collection process in n-type, high-purity germanium (HPGe) detectors of closed-end, coaxial geometry. The electron trajectories inside HPGe detectors are simulated using a phenomenological model to calculate the dependence of the drift velocity on the angle between the electric field and the crystal orientation. The resulting induced currents and pulse shapes for a given detector geometry and preamplifier bandwidth are compared to experiment. Experimentally, the dependence of the pulse shapes on the conductivity anisotropy in closed-end HPGe detectors was observed. The experimental data on pulse shapes were obtained by sampling preamplifier signals of an encapsulated, hexaconical EUROBALL detector, which was irradiated by collimated sup 2 sup 2 Na and sup 2 sup 4 sup 1 Am sources. The crystal orientation was measured by neutron reflection...

SOI detector with drift field due to majority carrier flow - an alternative to biasing in depletion

International Nuclear Information System (INIS)

Trimpl, M.; Deptuch, G.; Yarema, R.

2010-01-01

This paper reports on a SOI detector with drift field induced by the flow of majority carriers. It is proposed as an alternative method of detector biasing compared to standard depletion. N-drift rings in n-substrate are used at the front side of the detector to provide charge collecting field in depth as well as to improve the lateral charge collection. The concept was verified on a 2.5 x 2.5 mm 2 large detector array with 20 (micro)m and 40 (micro)m pixel pitch fabricated in August 2009 using the OKI semiconductor process. First results, obtained with a radioactive source to demonstrate spatial resolution and spectroscopic performance of the detector for the two different pixel sizes will be shown and compared to results obtained with a standard depletion scheme. Two different diode designs, one using a standard p-implantation and one surrounded by an additional BPW implant will be compared as well.

Mitigating Backgrounds with a Novel Thin-Film Cathode in the DRIFT-IId Dark Matter Detector

Science.gov (United States)

Miller, Eric H.

The nature of dark matter, which comprises 85% of the matter density in the universe, is a major outstanding question in physics today. The standard hypothesis is that the dark matter is a new weakly interacting massive particle, which is present throughout the galaxy. These particles could interact within detectors on Earth, producing low-energy nuclear recoils. Two distinctive signatures arise from the solar motion through the galaxy. The DRIFT experiment aims to measure one of these, the directional signature that is based on the sidereal modulation of the nuclear recoil directions. Although DRIFT has demonstrated its capability for detecting this signature, it has been plagued by a large number of backgrounds that have limited its reach. The focus of this thesis is on characterizing these backgrounds and describing techniques that have essentially eliminated them. The background events in the DRIFT-IId detector are predominantly caused by alpha decays on the central cathode in which the alpha particles completely or partially absorbed by the cathode material. This thesis describes the installation a 0.9 mum thick aluminized-mylar cathode as a way to reduce the probability of producing these backgrounds. We study three generations of cathode (wire, thin-film, and radiologically clean thin-film) with a focus on identifying and quantifying the sources of alpha decay backgrounds, as well as their contributions to the background rate in the detector. This in-situ study is based on alpha range spectroscopy and the determination of the absolute alpha detection efficiency. The results for the final radiologically clean version of the cathode give a contamination of 3.3 +/- 0.1 ppt 234U and 73 +/- 2 ppb 238U, and an efficiency for rejecting an RPR from an alpha decay that is a factor 70 +/- 20 higher than for the original wire cathode. Along with other background reduction measures, the thin-film cathode has reduced the observed background rate from 130/day to 1.7/day

Offline calibration procedure of the CMS Drift Tube detectors

International Nuclear Information System (INIS)

Abbiendi, G; Battilana, C; Cavallo, F R; Giunta, M; Guiducci, L; Amapane, N; Bolognesi, S; Cerminara, G; Bellan, R; Biallass, P; Frangenheim, J; Biasotto, M; Tazon, A Calderon; Cepeda, M; Cruz, B De La; Pardos, C Diez; Bedoya, C Fernandez; Iglesias, M C Fouz; Menendez, J Fernandez; Gresele, A

2009-01-01

The barrel region of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider is instrumented with Drift Tube (DT) detectors. This paper describes in full details the calibration of the DT hit reconstruction algorithm. After inter-channel synchronization has been verified through the appropriate hardware procedure, the time pedestals are extracted directly from the distribution of the recorded times. Further corrections for time-of-flight and time of signal propagation are applied as soon as the three-dimensional hit position within the DT chamber is known. The different effects of the time pedestal miscalibration on the two main hit reconstruction algorithms are shown. The drift velocity calibration algorithm is based on the meantimer technique. Different meantimer relations for different track angles and patterns of hit cells are used. This algorithm can also be used to determine the uncertainty on the reconstructed hit position.

Silicon Drift Detector response function for PIXE spectra fitting

Science.gov (United States)

Calzolai, G.; Tapinassi, S.; Chiari, M.; Giannoni, M.; Nava, S.; Pazzi, G.; Lucarelli, F.

2018-02-01

The correct determination of the X-ray peak areas in PIXE spectra by fitting with a computer program depends crucially on accurate parameterization of the detector peak response function. In the Guelph PIXE software package, GUPIXWin, one of the most used PIXE spectra analysis code, the response of a semiconductor detector to monochromatic X-ray radiation is described by a linear combination of several analytical functions: a Gaussian profile for the X-ray line itself, and additional tail contributions (exponential tails and step functions) on the low-energy side of the X-ray line to describe incomplete charge collection effects. The literature on the spectral response of silicon X-ray detectors for PIXE applications is rather scarce, in particular data for Silicon Drift Detectors (SDD) and for a large range of X-ray energies are missing. Using a set of analytical functions, the SDD response functions were satisfactorily reproduced for the X-ray energy range 1-15 keV. The behaviour of the parameters involved in the SDD tailing functions with X-ray energy is described by simple polynomial functions, which permit an easy implementation in PIXE spectra fitting codes.

Effect of Anode Floating Voltage and its Applications in Characterizing Silicon Drift Detectors

International Nuclear Information System (INIS)

Guang-Guo, Wu; Hong-Ri, Li; Kun, Liang; Ru, Yang; De-Jun, Han; Xue-Lei, Cao; Huan-Yu, Wang; Jun-Ming, An; Xiong-Wei, Hu

2009-01-01

Anode Boating voltage is predicted and investigated for silicon drift detectors (SDDs) with an active area of 5 mm 2 fabricated by a double-side parallel technology. It is demonstrated that the anode Boating voltage increases with the increasing inner ring voltage, and is almost unchanged with the external ring voltage. The anode Boating voltage will not be affected by the back electrode biased voltage until it reaches the full-depleted voltage (−50 V) of the SDD. Theoretical analysis and experimental results show that the anode Boating voltage is equal to the sum of the inner ring voltage and the built-in potential between the p + inner ring and the n + anode. A fast checking method before detector encapsulation is proposed by employing the anode Boating voltage along with checking the leakage current, potential distribution and drift properties

3D design and electric simulation of a silicon drift detector using a spiral biasing adapter

Energy Technology Data Exchange (ETDEWEB)

Li, Yu-yun; Xiong, Bo [School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105 (China); Center for Semiconductor Particle and photon Imaging Detector, Development and Fabrication, Xiangtan University, Xiangtan 411105 (China); Li, Zheng, E-mail: zhengli58@gmail.com [School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105 (China); Center for Semiconductor Particle and photon Imaging Detector, Development and Fabrication, Xiangtan University, Xiangtan 411105 (China)

2016-09-21

The detector system of combining a spiral biasing adapter (SBA) with a silicon drift detector (SBA-SDD) is largely different from the traditional silicon drift detector (SDD), including the spiral SDD. It has a spiral biasing adapter of the same design as a traditional spiral SDD and an SDD with concentric rings having the same radius. Compared with the traditional spiral SDD, the SBA-SDD separates the spiral's functions of biasing adapter and the p–n junction definition. In this paper, the SBA-SDD is simulated using a Sentaurus TCAD tool, which is a full 3D device simulation tool. The simulated electric characteristics include electric potential, electric field, electron concentration, and single event effect. Because of the special design of the SBA-SDD, the SBA can generate an optimum drift electric field in the SDD, comparable with the conventional spiral SDD, while the SDD can be designed with concentric rings to reduce surface area. Also the current and heat generated in the SBA are separated from the SDD. To study the single event response, we simulated the induced current caused by incident heavy ions (20 and 50 μm penetration length) with different linear energy transfer (LET). The SBA-SDD can be used just like a conventional SDD, such as X-ray detector for energy spectroscopy and imaging, etc. - Highlights: • The separation of the spiral biasing adapter and SDD is a new concept. • The distribution of the electric potential is symmetrical around the axis through the anode. • The region with higher electron concentrations defines the drift channel.

Development of a simplified simulation model for performance characterization of a pixellated CdZnTe multimodality imaging system

Energy Technology Data Exchange (ETDEWEB)

Guerra, P; Santos, A [Departamento de IngenierIa Electronica, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Darambara, D G [Joint Department of Physics, Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, Fulham Road, London SW3 6JJ (United Kingdom)], E-mail: pguerra@die.um.es

2008-02-21

Current requirements of molecular imaging lead to the complete integration of complementary modalities in a single hybrid imaging system to correlate function and structure. Among the various existing detector technologies, which can be implemented to integrate nuclear modalities (PET and/or single-photon emission computed tomography with x-rays (CT) and most probably with MR, pixellated wide bandgap room temperature semiconductor detectors, such as CdZnTe and/or CdTe, are promising candidates. This paper deals with the development of a simplified simulation model for pixellated semiconductor radiation detectors, as a first step towards the performance characterization of a multimodality imaging system based on CdZnTe. In particular, this work presents a simple computational model, based on a 1D approximate solution of the Schockley-Ramo theorem, and its integration into the Geant4 application for tomographic emission (GATE) platform in order to perform accurately and, therefore, improve the simulations of pixellated detectors in different configurations with a simultaneous cathode and anode pixel readout. The model presented here is successfully validated against an existing detailed finite element simulator, the multi-geometry simulation code, with respect to the charge induced at the anode, taking into consideration interpixel charge sharing and crosstalk, and to the detector charge induction efficiency. As a final point, the model provides estimated energy spectra and time resolution for {sup 57}Co and {sup 18}F sources obtained with the GATE code after the incorporation of the proposed model.

Drift tubes for the SAMUS muon spectrometer of the DO detector

International Nuclear Information System (INIS)

Antipov, Yu.M.; Bezzubov, V.A.; Denisov, D.S.; Evdokimov, V.N.; Pishal'nikov, Yu.M.; Stoyanova, D.A.

1989-01-01

The construction and manufacturing procedure of 6000 drift tubes for the SAMUS muon spectrometer of the DO detector are described in detail. The diameter of the stainless steel tubes is 30mm, their length varies within the range from 0.2 to 3.8 m. A testing procedure of the main parameters of the tubes is proposed and the results of testing all the tubes after manufacturing are given. With the pure methane filling the maximum drift time for electrons is 0.16 μs, the plateau of effective detection of minimum ionizing particles is equal to 1.0 kV and the coordinate resolution is 0.3 mm. 12 refs.; 9 figs.; 4 tabs

Works of art investigation with silicon drift detectors

CERN Document Server

Leutenegger, P; Fiorini, C; Strüder, L; Kemmer, J; Lechner, P; Sciuti, S; Cesareo, R

2000-01-01

The X-ray fluorescence (XRF) spectroscopy analysis is a non-destructive technique widely used in archeometry to investigate the chemical composition of pigments, metal alloys and stones for restoration and historical investigation. The classical detection systems for archeometrical investigations utilize cryogenic detectors, like Si(Li) and HPGe, characterized by a satisfactory energy resolution (of the order of 140 eV FWHM at 6 keV). However, the requirements of liquid N sub 2 drastically limit the portability of such systems, limiting the possibility of making measurements 'on the field'. Recently new silicon PIN diodes Peltier cooled were introduced, allowing the construction of portable instrumentation. However, their energy resolution (of the order of 250 eV FWHM at 6 keV) results in some cases unsatisfactory (for instance in the identification of light elements). Both the requirements of portability and good energy resolution are fulfilled by the silicon drift detector (SDD). The SDD, cooled by a Peltie...

Theoretical evaluation of the Doppler broadening contribution to the angular resolution in CdZnTe Compton scattering detector

International Nuclear Information System (INIS)

Diaz Garcia, A.; Cabal Rodriguez, A.E.; Rubio Rodriguez, J. A.; Salicio Diez, J.; Perez Morales, J.M.; Vela Morales, O.; Willmott Zappacosta, C.; Van Espen, P.

2011-01-01

Electronically collimated Compton Cameras have been tested in Single Photon Emission Tomography (SPECT) systems instead of mechanically collimated gamma detectors in order to improve their limited sensitivity. One of the main factors that contribute to the worsening of the angular resolution and thus to the deterioration of the system spatial resolution is Doppler broadening. Double differential Klein-Nishina equation is used to consider the random movement of electron inside the crystal. It is important to perform this analysis for each particular material because is difficult to infer one simple Doppler broadening dependency of the atomic number Z. In high Z materials the internal electrons are strongly linked to the nucleus and therefore there can be found high momentums, but they represent just a small portion of the electrons that suffers Compton scattering. This work estimates the influence of the Doppler broadening in CdZnTe semiconductor for different incoming photon energies. For this means there are analyzed main Compton broadening processes in semiconductor Cd 0,8 Zn 0,2 Te with density ρ=5,85g/cm 3 . (Author)

Silicon drift detectors in alice experiment at lhc, performance tests and simulations

International Nuclear Information System (INIS)

ALICE collaboration

2001-01-01

A brief introduction to the silicon drift detector (SDD) in ALICE experiment at LHC CERN. Excellent agreement are found between the results from the simulation code (Ali Root) and the results of the test beam data for SDD s. A study of SDD performance and double track separation capability are shown

A doublet of 3" cylindrical silicon drift detectors in the CERES/NA45 experiment

CERN Document Server

Faschingbauer, U; Baur, R; Ceretto, F; Drees, A; Fraenkel, Zeev; Fuchs, C; Gatti, E; Glässel, P; Hemberger, M; Pérez de los Heros, C; Hess, F; Holl, P; Irmscher, D; Jacob, C; Kemmer, J; Minaev, Yu I; Panebratsev, Yu A; Pfeiffer, A; Ravinovich, I; Razin, S V; Rehak, P; Sampietro, M; Schükraft, Jürgen; Shimansky, S S; Socol, E; Specht, H J; Tel-Zur, G; Tserruya, Itzhak; Ullrich, T S; Voigt, C A; Wurm, J P; Yurevich, V I

1995-01-01

We report on the performance of a doublet of 3" cylindrical silicon drift detectors installed as an upgrade of the CERES/NA45 electron pair spectrometer for the Pb-beam at the CERN SPS. The silicon detectors provide external particle tracking and background rejection of conversions and close Dalitz pairs. Results on vertex reconstruction and rejection from Pb test-run in 1994 are presented.

Development of Muon Drift-Tube Detectors for High-Luminosity Upgrades of the Large Hadron Collider

CERN Document Server

Bittner, B; Kortner, O.; Kroha, H.; Legger, F.; Richter, R.; Biebel, O.; Engl, A.; Hertenberger, R.; Rauscher, F.

2016-01-01

The muon detectors of the experiments at the Large Hadron Collider (LHC) have to cope with unprecedentedly high neutron and gamma ray background rates. In the forward regions of the muon spectrometer of the ATLAS detector, for instance, counting rates of 1.7 kHz/square cm are reached at the LHC design luminosity. For high-luminosity upgrades of the LHC, up to 10 times higher background rates are expected which require replacement of the muon chambers in the critical detector regions. Tests at the CERN Gamma Irradiation Facility showed that drift-tube detectors with 15 mm diameter aluminum tubes operated with Ar:CO2 (93:7) gas at 3 bar and a maximum drift time of about 200 ns provide e?cient and high-resolution muon tracking up to the highest expected rates. For 15 mm tube diameter, space charge e?ects deteriorating the spatial resolution at high rates are strongly suppressed. The sense wires have to be positioned in the chamber with an accuracy of better than 50 ?micons in order to achieve the desired spatial...

Optical and electrical study of CdZnTe surfaces passivated by KOH and NH{sub 4}F solutions

Energy Technology Data Exchange (ETDEWEB)

Zázvorka, J., E-mail: zazvorka.jakub@gmail.com [Institute of Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Prague (Czech Republic); Franc, J.; Statelov, M.; Pekárek, J.; Veis, M.; Moravec, P. [Institute of Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Prague (Czech Republic); Mašek, K. [Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, CZ, 18000 Prague (Czech Republic)

2016-12-15

Highlights: • Surface of CdZnTe samples was passivated after chemical etching. • KOH and NH{sub 4}F solutions were used as passivation agents. • Growth of surface oxide after passivation is observed. • Surface oxide thickness was evaluated over time after chemical treatment. • Oxidation of the sample correlates with decreased leakage current. - Abstract: Performance of CdZnTe-based detectors is highly related to surface preparation. Mechanical polishing, chemical etching and passivation are routinely employed for this purpose. However, the relation between these processes and the detector performance in terms of underlying physical phenomena has not been fully explained. The dynamics and properties of CdZnTe surface oxide layers, created by passivation with KOH and NH4F/H2O2 solutions, were studied by optical ellipsometry and X-ray photoelectron spectroscopy (XPS). Thicknesses and growth rates of the surface oxide layers differed for each of the passivation methods. Leakage currents which influence the final spectral resolution of the detector were measured simultaneously with ellipsometry. Results of both optical and electrical investigation showed the same trends in the time evolution and correlated to each other. NH4F/H2O2 passivation showed to be a method which produces the most desirable properties of the surface oxide layer.

Silicon drift detectors with on-chip electronics for x-ray spectroscopy.

Science.gov (United States)

Fiorini, C; Longoni, A; Hartmann, R; Lechner, P; Strüder, L

1997-01-01

The silicon drift detector (SDD) is a semiconductor device based on high resistivity silicon fully depleted through junctions implanted on both sides of the semiconductor wafer. The electrons generated by the ionizing radiation are driven by means of a suitable electric field from the point of interaction toward a collecting anode of small capacitance, independent of the active area of the detector. A suitably designed front-end JFET has been directly integrated on the detector chip close to the anode region, in order to obtain a nearly ideal capacitive matching between detector and transistor and to minimize the stray capacitances of the connections. This feature allows it to reach high energy resolution also at high count rates and near room temperature. The present work describes the structure and the performance of SDDs specially designed for high resolution spectroscopy with soft x rays at high detection rate. Experimental results of SDDs used in spectroscopy applications are also reported.

Characterization of semi-insulating materials by photoinduced current transient spectroscopy: Fe doped INP for micro-optoelectronics and CdZnTe for nuclear detection

International Nuclear Information System (INIS)

Cherkaoui, K.

1998-01-01

The need of semi-insulating materials, of great quality, concerns various application domains. For instance, the very resistive substrates InP and CdZnTe are respectively adapted to the micro-optoelectronic circuits and to nuclear detectors. These two materials have been characterized by the thermal photoinduced current transient spectroscopy. The first part of this thesis is the defects analysis of annealing InP substrates, to understand the compensation process of this material. Two activation energy levels around 0,2 to 0,4 eV resulting from the thermal treatment have been detected. The iron omnipresence in the substrates, even undoped, has been noticed. It is then necessary to take into account the iron presence to understand the compensation process in these InP annealing substrates. the second part presents the study of the CdZnTe material, elaborated by the Bridgman method, to emphasize the defects leading to the decrease of the detector performances. The presence of three deep levels, near the forbidden band middle, is in relation with the detectors performances. (A.L.B.)

Performance of the front-end signal processing electronics for the drift chambers of the Stanford Large Detector

International Nuclear Information System (INIS)

Honma, A.; Haller, G.M.; Usher, T.; Shypit, R.

1990-10-01

This paper reports on the performance of the front-end analog and digital signal processing electronics for the drift chambers of the Stanford Large Detector (SLD) detector at the Stanford Linear Collider. The electronics mounted on printed circuit boards include up to 64 channels of transimpedance amplification, analog sampling, A/D conversion, and associated control circuitry. Measurements of the time resolution, gain, noise, linearity, crosstalk, and stability of the readout electronics are described and presented. The expected contribution of the electronics to the relevant drift chamber measurement resolutions (i.e., timing and charge division) is given

Feasibility of conversion electron spectrometry using a Peltier-cooled silicon drift detector

International Nuclear Information System (INIS)

Perajarvi, K.; Turunen, J.; Ihantola, S.; Pollanen, R.; Siiskonen, T.; Toivonen, H.; Kamarainen, V.; Pomme, S.

2014-01-01

A Peltier-cooled silicon drift detector was successfully applied for conversion electron spectrometry. The energy resolution of the detector for 45 keV electrons was 0.50 keV (FWHM). The approximate thickness of the dead layer was determined to be 140 ± 20 nm Si equivalent. The relative efficiency of the detector was verified to be approximately constant in the energy range of 17-75 keV. This is concordant with the high transparency of the thin dead layer and the sufficient thickness of the detector (450 μm) to stop the electrons. The detector is suitable for use in plutonium analysis of chemically prepared samples. Moreover, it was demonstrated that conversion electron spectrometry is better than alpha spectrometry in preserving its capability to determine the 240 Pu/ 239 Pu isotopic ratio as a function of sample thickness. The investigated measurement technique can be considered a promising new tool in safeguards, complementary to existing methods. (author)

Thermodynamics of post-growth annealing of cadmium zinc telluride nuclear radiation detectors

Science.gov (United States)

Adams, Aaron Lee

Nuclear Radiation Detectors are used for detecting, tracking, and identifying radioactive materials which emit high-energy gamma and X-rays. The use of Cadmium Zinc Telluride (CdZnTe) detectors is particularly attractive because of the detector's ability to operate at room temperature and measure the energy spectra of gamma-ray sources with a high resolution, typically less than 1% at 662 keV. While CdZnTe detectors are acceptable imperfections in the crystals limit their full market potential. One of the major imperfections are Tellurium inclusions generated during the crystal growth process by the retrograde solubility of Tellurium and Tellurium-rich melt trapped at the growth interface. Tellurium inclusions trap charge carriers generated by gamma and X-ray photons and thus reduce the portion of generated charge carriers that reach the electrodes for collection and conversion into a readable signal which is representative of the ionizing radiation's energy and intensity. One approach in resolving this problem is post-growth annealing which has the potential of removing the Tellurium inclusions and associated impurities. The goal of this project is to use experimental techniques to study the thermodynamics of Tellurium inclusion migration in post-growth annealing of CdZnTe nuclear detectors with the temperature gradient zone migration (TGZM) technique. Systematic experiments will be carried out to provide adequate thermodynamic data that will inform the engineering community of the optimum annealing parameters. Additionally, multivariable correlations that involve the Tellurium diffusion coefficient, annealing parameters, and CdZnTe properties will be analyzed. The experimental approach will involve systematic annealing experiments (in Cd vapor overpressure) on different sizes of CdZnTe crystals at varying temperature gradients ranging from 0 to 60°C/mm (used to migrate the Tellurium inclusion to one side of the crystal), and at annealing temperatures ranging

Development of a CZT drift ring detector for X and γ ray spectroscopy

Science.gov (United States)

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 γ 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.

Next Generation Semiconductor-Based Radiation Detectors Using Cadmium Magnesium Telluride

Energy Technology Data Exchange (ETDEWEB)

Trivedi, Sudhir B [Brimrose Technology Corporation, Sparks Glencoe, MD (United States); Kutcher, Susan W [Brimrose Technology Corporation, Sparks Glencoe, MD (United States); Palsoz, Witold [Brimrose Technology Corporation, Sparks Glencoe, MD (United States); Berding, Martha [SRI International, Menlo Park, CA (United States); Burger, Arnold [Brimrose Technology Corporation, Sparks Glencoe, MD (United States)

2014-11-17

The primary objective of Phase I was to perform extensive studies on the purification, crystal growth and annealing procedures of CdMgTe to gain a clear understanding of the basic material properties to enable production of detector material with performance comparable to that of CdZnTe. Brimrose utilized prior experience in the growth and processing of II-VI crystals and produced high purity material and good quality single crystals of CdMgTe. Processing techniques for these crystals including annealing, mechanical and chemical polishing, surface passivation and electrode fabrication were developed. Techniques to characterize pertinent electronic characteristics were developed and gamma ray detectors were fabricated. Feasibility of the development of comprehensive defect modeling in this new class of material was demonstrated by our partner research institute SRI International, to compliment the experimental work. We successfully produced a CdMgTe detector that showed 662 keV gamma response with energy resolution of 3.4% (FWHM) at room temperature, without any additional signal correction. These results are comparable to existing CdZnTe (CZT) technology using the same detector size and testing conditions. We have successfully demonstrated detection of gamma-radiation from various isotopes/sources, using CdMgTe thus clearly proving the feasibility that CdMgTe is an excellent, low-cost alternative to CdZnTe.

Development of (Cd,Zn)Te X-ray and gamma ray radiation detectors for medical and security applications

International Nuclear Information System (INIS)

Franc, J.; Hoeschl, P.; Belas, E.; Grill, V.; Fauler, A.; Dambacher, M.; Procz, S.

2011-01-01

Full text: There is a growing need for large area X-and Gamma radiation detectors for penetrating radiations in various fields of application e.g. astronomy, detectors for nuclear medicine, biosensor materials, security, non-proliferation of hazardous materials, and environmental applications etc. Direct X-rays conversion into electric charges in a semiconductor is envisaged with better spectroscopic characteristics to improve contrast and quantitative measurements compared to indirect detection using scintillators. The family of II-VI semiconductor materials combine a range of excellent properties such as their high sensitivity due to the high mobility-lifetime products, their high energy resolution as a consequence of the electron-hole pair formation energy, their reasonable maturity in terms of microelectronic technologies required for commercial detector fabrication, wide range of stopping power and band-gaps available. In particular, CdTe and Cd x Zn 1-x Te (CZT) with Zn=0.1 offer a favorable combination of physical and chemical properties that makes it attractive as a room temperature X-ray detector material of choice for many applications involving photon energies up to several hundreds of keV. From the scientific experience accumulated in the past years, the detector properties are strongly dependent on a series of parameters which must be strictly controlled during crystal growth, such as the homogeneity, stoichiometry and the related intrinsic defects which appear during the material growth, a high mobility-lifetime for electron and holes is mandatory etc. Production of detector-grade CdTe and CdZnTe on industrial scale is still a challenge and optimal growth methods and growth conditions have been under intensive investigation. Progress in crystal growth and characterization achieved in a project of Institute partnership between Charles University in Prague and University of Freiburg, Germany which was sponsored by Alexander von Humboldt Foundation, will

Live-monitoring of Te inclusions laser-induced thermo-diffusion and annealing in CdZnTe crystals

International Nuclear Information System (INIS)

Zappettini, A.; Zambelli, N.; Benassi, G.; Calestani, D.; Pavesi, M.

2014-01-01

The presence of Te inclusions is one of the main factors limiting performances of CdZnTe crystals as X-ray detectors. We show that by means of infrared laser radiation it is possible to move and anneal tellurium inclusions exploiting a thermo-diffusion mechanism. The process is studied live during irradiation by means of an optical microscope equipment. Experimental conditions, and, in particular, energy laser fluence, for annealing inclusions of different dimensions are determined.

Live-monitoring of Te inclusions laser-induced thermo-diffusion and annealing in CdZnTe crystals

Energy Technology Data Exchange (ETDEWEB)

Zappettini, A.; Zambelli, N.; Benassi, G.; Calestani, D. [Istituto Materiali Elettronica e Magnetismo – Consiglio Nazionale delle Ricerche, Parma (Italy); Pavesi, M. [Istituto Materiali Elettronica e Magnetismo – Consiglio Nazionale delle Ricerche, Parma (Italy); Istituto di Fisica e Scienze della Terra, Università degli Studi di Parma, Parma (Italy)

2014-06-23

The presence of Te inclusions is one of the main factors limiting performances of CdZnTe crystals as X-ray detectors. We show that by means of infrared laser radiation it is possible to move and anneal tellurium inclusions exploiting a thermo-diffusion mechanism. The process is studied live during irradiation by means of an optical microscope equipment. Experimental conditions, and, in particular, energy laser fluence, for annealing inclusions of different dimensions are determined.

Local Trigger Electronics for the CMS Drift Tubes Muon detector

CERN Document Server

Travaglini, R

2003-01-01

In the CMS detector in preparation for the CERN LHC collider, the Drift Tubes Muon Chambers are equipped with mini-crates hosting custom electronics for fast data processing and local trigger generation. In particular the Trigger Server of a DTC consists of Track Sorter Slave ASICs and a Track Sorter Master system. The trigger electronics boards are in production, to be ready for the muon detector installation in the CMS barrel starting at the end of 2003.In this work, the performance of the Trigger Server will be discussed, on the basis both of high-statistics tests with predefined patterns and of test beam data collected at CERN, where a DTC was exposed to a muon beam having an LHC-like bunch structure. Finally, some system performance expectations, concerning radiation tolerance and signal transmission issues during LHC running, will be also discussed.

Improved method for the stabilization of NaI-photomultiplier gamma detectors against thermal and other drift

International Nuclear Information System (INIS)

Zucker, M.S.

1985-01-01

Alpha peaks have been used as part of servo systems to stabilize NaI-photomultiplier gamma detectors against drift. However, alpha peaks shift with temperature change differently than do gamma peaks, thus spoiling what would otherwise be a workable scheme for stabilizing against probably the most serious source of NaI-p.m. detector drift, namely thermal effects. It has been found possible to accurately compensate for the difference in the shift with temperature versus gamma peaks using the signal derived from a thermistor in thermal contact with the NaI crystal to control the bias of a discriminator in the servo circuit. The servo circuit utilizing this principle has been used in commercial multichannel analyzers of the type intended for field use under adverse ambient conditions

Development, construction and test of the planar forward drift chambers of the ZEUS inner detector and analyses of chamber properties

International Nuclear Information System (INIS)

Kramarczyk, S.

1993-08-01

The three planar drift chambers FTD1-3 are part of the inner tracking system of the ZEUS detector at the ep facility HERA, DESY. Together with 2x2 transition radiation modules they form the Forward Detector which covers the range of forward (proton) angles. Development, construction and tests of the drift chambers are described, emphasizing design features and details of the manufacture. Two compensation methods were tested to annihilate the cross talk which emerges from the influence of one signal wire on the others in the same drift cell. A prototyp system of the final digital readout electronics was used together with a test cell. The single wire resolution was studied with optimized drift time algorithms. For the first time it was possible to measure the influence of the track angle on the single wire resolution of the FTDs. (orig.)

Alignment of the drift tube detector at the neutrino oscillation experiment OPERA

International Nuclear Information System (INIS)

Goellnitz, Christoph

2012-09-01

The present thesis was composed during the course of the OPERA experiment, which aims to give a direct evidence for neutrino oscillations in the channel ν μ → ν τ . The OPERA detector is designed to observe the appearance of tau neutrinos in an originally pure muon neutrino beam, the CNGS beam. As important part of the detector the precision tracker (PT), a drift tube detector, consists of 9504 drift tubes in 198 modules. In this thesis, several parts of the slow control of the PT are developed and implemented to ensure operation during data taking over several years. The main part is the geometric calibration, the alignment of the detector. The alignment procedure contains both hardware and software parts, the software methods are developed and applied. Using straight particle tracks, the detector components are geometrically corrected. A special challenge for the alignment for the PT is the fact that at this kind of low-rate experiment only a small number of particle tracks is available. With software-based corrections of the module rotation, a systematic error of 0.2 mrad has been attained, for corrections of translation, a systematic error of 32 μm is reached. For the alignment between two adjacent PT walls, the statistical error is less than 8 μm. All results of the position monitoring system are considered. All developed methods are tested with Monte Carlo simulations. The detector requirements (Δp/p ≤ 0.25 below 25 GeV) are met. The analysis of the momentum measurement for high energies above 25 GeV demonstrates the resulting improvement. The mean momentum is falling significantly using the new alignment values. The significance of the detector alignment becomes most evident in the analysis of cosmic particles. The muon charge ratio R μ is expected not to be angular dependent. The χ 2 probability of the measured distribution improves up to 58%. The muon charge ratio was also investigated in dependence of particle energy in terms of the alignment

Scalability, Scintillation Readout and Charge Drift in a Kilogram Scale Solid Xenon Particle Detector

Energy Technology Data Exchange (ETDEWEB)

Yoo, J. [Fermilab; Cease, H. [Fermilab; Jaskierny, W. F. [Fermilab; Markley, D. [Fermilab; Pahlka, R. B. [Fermilab; Balakishiyeva, D. [Florida U.; Saab, T. [Florida U.; Filipenko, M. [Erlangen - Nuremberg U., ECAP

2014-10-23

We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employ a liquid nitrogen cooled cryostat combined with a xenon purification and chiller system to measure the scintillation light output and electron drift speed from both the solid and liquid phases of xenon. Scintillation light output from sealed radioactive sources is measured by a set of high quantum efficiency photomultiplier tubes suitable for cryogenic applications. We observed a reduced amount of photons in solid phase compared to that in liquid phase. We used a conventional time projection chamber system to measure the electron drift time in a kilogram of solid xenon and observed faster electron drift speed in the solid phase xenon compared to that in the liquid phase.

Development and characterisation of new high-rate muon drift tube detectors

Energy Technology Data Exchange (ETDEWEB)

Bittner, Bernhard

2012-07-25

With the increase of the LHC luminosity above the design value and the higher background counting rates, detectors in the ATLAS muon spectrometer have to be replaced because the limits of the radiation tolerance will be exceeded. Therefore drift tube chambers with 15 mm tube diameter were developed. The required construction accuracy was verified and the limits of the resolution and efficiency were determined in a muon beam and under gamma irradiation and compared to model expectations.

Design study of a low-power, low-noise front-end for multianode silicon drift detectors

International Nuclear Information System (INIS)

Caponetto, L.; Presti, D. Lo; Randazzo, N.; Russo, G.V.; Leonora, E.; Lo Nigro, L.; Petta, C.; Reito, S.; Sipala, V.

2005-01-01

The read-out for Silicon Drift Detectors in the form of a VLSI chip is presented, with a view to applications in High Energy Physics and space experiments. It is characterised by extremely low power dissipation, small noise and size

Image compression for the silicon drift detectors in the ALICE experiment

International Nuclear Information System (INIS)

Werbrouck, A.; Tosello, F.; Rivetti, A.; Mazza, G.; De Remigis, P.; Cavagnino, D.; Alberici, G.

2001-01-01

We describe an algorithm for the zero suppression and data compression for the Silicon Drift Detectors (SDD) in the ALICE experiment. The algorithm operates on 10-bit linear data streams from the SDDs by applying a 10 bit to 8-bit non-linear compression followed by a data reduction based on a two-threshold discrimination and a two-dimensional analysis along both the drift time and the anodes. The proposed scheme allows for a better understanding of the neighborhoods of the SDD signal clusters, thus improving their reconstructability, and also provides a statistical monitoring of the background characteristics for each SDD anode. The entire algorithm is purely combinatorial and thus can be executed in pipeline, without additional clock cycles, during the SDD readout. The hardware coding together with the methods for the expansion to the original 10-bit values in the offline analysis and for the background monitoring are presented

Physical packaging and organization of the drift chamber electronics system for the Stanford Large Detector

International Nuclear Information System (INIS)

Haller, G.M.; Freytag, M.L.; Mazaheri, G.; Olsen, J.; Paffrath, L.

1990-10-01

In this paper the logical organization, physical packaging, and operation of the drift chamber electronics for the SLD at SLAC is described. The system processes signals from approximately 7000 drift wires and is unusual in that most electronic functions are packaged on printed circuit boards within the detector. The circuits reside on signal-processing motherboards, controller boards, signal-transition boards, power-distribution boards, and fiber-optics-to-electrical conversion boards. The interaction and interconnection of these boards with respect to signal and control flow are presented. 11 refs., 7 figs

X-ray response of CdZnTe detectors grown by the vertical Bridgman technique: Energy, temperature and high flux effects

Energy Technology Data Exchange (ETDEWEB)

Abbene, L., E-mail: leonardo.abbene@unipa.it [Dipartimento di Fisica e Chimica (DiFC), Università di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy); Gerardi, G.; Turturici, A.A.; Raso, G. [Dipartimento di Fisica e Chimica (DiFC), Università di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy); Benassi, G. [due2lab s.r.l., Via Paolo Borsellino 2, Scandiano, Reggio Emilia 42019 (Italy); Bettelli, M. [IMEM/CNR, Parco Area delle Scienze 37/A, Parma 43100 (Italy); Zambelli, N. [due2lab s.r.l., Via Paolo Borsellino 2, Scandiano, Reggio Emilia 42019 (Italy); Zappettini, A. [IMEM/CNR, Parco Area delle Scienze 37/A, Parma 43100 (Italy); Principato, F. [Dipartimento di Fisica e Chimica (DiFC), Università di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy)

2016-11-01

Nowadays, CdZnTe (CZT) is one of the key materials for the development of room temperature X-ray and gamma ray detectors and great efforts have been made on both the device and the crystal growth technologies. In this work, we present the results of spectroscopic investigations on new boron oxide encapsulated vertical Bridgman (B-VB) grown CZT detectors, recently developed at IMEM-CNR Parma, Italy. Several detectors, with the same electrode layout (gold electroless contacts) and different thicknesses (1 and 2.5 mm), were realized: the cathode is a planar electrode covering the detector surface (4.1×4.1 mm{sup 2}), while the anode is a central electrode (2×2 mm{sup 2}) surrounded by a guard-ring electrode. The detectors are characterized by electron mobility-lifetime product (µ{sub e}τ{sub e}) values ranging between 0.6 and 1·10{sup −3} cm{sup 2}/V and by low leakage currents at room temperature and at high bias voltages (38 nA/cm{sup 2} at 10000 V/cm). The spectroscopic response of the detectors to monochromatic X-ray and gamma ray sources ({sup 109}Cd, {sup 241}Am and {sup 57}Co), at different temperatures and fluxes (up to 1 Mcps), was measured taking into account the mitigation of the effects of incomplete charge collection, pile-up and high flux radiation induced polarization phenomena. A custom-designed digital readout electronics, developed at DiFC of University of Palermo (Italy), able to perform a fine pulse shape and height analysis even at high fluxes, was used. At low rates (200 cps) and at room temperature (T=25 °C), the detectors exhibit an energy resolution FWHM around 4% at 59.5 keV, for comparison an energy resolution of 3% was measured with Al/CdTe/Pt detectors by using the same electronics (A250F/NF charge sensitive preamplifier, Amptek, USA; nominal ENC of 100 electrons RMS). At high rates (750 kcps), energy resolution values of 7% and 9% were measured, with throughputs of 2% and 60% respectively. No radiation polarization phenomena were

A 240-channel thick film multi-chip module for readout of silicon drift detectors

International Nuclear Information System (INIS)

Lynn, D.; Bellwied, R.; Beuttenmueller, R.; Caines, H.; Chen, W.; DiMassimo, D.; Dyke, H.; Elliott, D.; Grau, M.; Hoffmann, G.W.; Humanic, T.; Jensen, P.; Kleinfelder, S.A.; Kotov, I.; Kraner, H.W.; Kuczewski, P.; Leonhardt, B.; Li, Z.; Liaw, C.J.; LoCurto, G.; Middelkamp, P.; Minor, R.; Mazeh, N.; Nehmeh, S.; O'Conner, P.; Ott, G.; Pandey, S.U.; Pruneau, C.; Pinelli, D.; Radeka, V.; Rescia, S.; Rykov, V.; Schambach, J.; Sedlmeir, J.; Sheen, J.; Soja, B.; Stephani, D.; Sugarbaker, E.; Takahashi, J.; Wilson, K.

2000-01-01

We have developed a thick film multi-chip module for readout of silicon drift (or low capacitance ∼200 fF) detectors. Main elements of the module include a custom 16-channel NPN-BJT preamplifier-shaper (PASA) and a custom 16-channel CMOS Switched Capacitor Array (SCA). The primary design criteria of the module were the minimizations of the power (12 mW/channel), noise (ENC=490 e - rms), size (20.5 mmx63 mm), and radiation length (1.4%). We will discuss various aspects of the PASA design, with emphasis on the preamplifier feedback network. The SCA is a modification of an integrated circuit that has been previously described [1]; its design features specific to its application in the SVT (Silicon Vertex Tracker in the STAR experiment at RHIC) will be discussed. The 240-channel multi-chip module is a circuit with five metal layers fabricated in thick film technology on a beryllia substrate and contains 35 custom and commercial integrated circuits. It has been recently integrated with silicon drift detectors in both a prototype system assembly for the SVT and a silicon drift array for the E896 experiment at the Alternating Gradient Synchrotron at the Brookhaven National Laboratory. We will discuss features of the module's design and fabrication, report the test results, and emphasize its performance both on the bench and under experimental conditions

Interface chemistry of CdZnTe films studied by a peel-off approach

Energy Technology Data Exchange (ETDEWEB)

Tao, Jun; Xu, Haitao; Zhang, Yuelu; Ji, Huanhuan; Xu, Run, E-mail: runxu@staff.shu.edu.cn; Huang, Jian; Zhang, Jijun; Liang, Xiaoyan; Tang, Ke; Wang, Linjun, E-mail: ljwang@shu.edu.cn

2016-12-01

Highlights: • A peel-off approach is adopted to study the interface chemistry of CdZnTe films. • A thick mixed interlayer above 84 nm is found at a low growth temperature of 200 °C. • A reaction-limited model is suggested to explain the formation of mixed interlayer. - Abstract: CdZnTe films with thickness above 50 μm were deposited at temperatures of 200–500 °C by Close Space Sublimation method. A peel-off approach has been adopted to study the interface chemistry of CdZnTe thick films. For all the CdZnTe films, the scanning electron microscopy images show the small and round-like grains formed at interface in contrast to the large ordered grains at surface. For CdZnTe films grown at a low substrate temperature of 200 °C, the interface layer between CdZnTe and substrate is mixed with Te and CdTe, as evidenced by X-ray diffraction, Raman and X-ray photoelectron spectroscopy results. The thickness of the interface layer can be estimated to be 84 nm by depth profile using X-ray photoelectron spectroscopy. In contrast, a thin interface layer less than 14 nm is found at a high substrate temperature of 500 °C. The limited reaction of Te{sub 2} and Cd (Zn) to CdZnTe at a low growth temperature is responsible for the formation of the thick interface layer and a slow deposition rate at the nucleation stage.

Vapour growth of Cd(Zn)Te columnar nanopixels into porous alumina

International Nuclear Information System (INIS)

Sochinskii, N.V.; Abellan, M.; Martin Gonzalez, M.; Saucedo, E.; Dieguez, E.; Briones, F.

2006-01-01

The vapour phase growth (VPG) of CdTe and Cd 1- x Zn x Te was performed in order to investigate the formation of Cd(Zn)Te columnar nanostructures, which could serve as a basis for micropixels usable for further development of X- and gamma-ray high-resolution imaging devices. The possibility to form the 'Cd(Zn)Te-in-porous alumina' nanostructures by VPG has been demonstrated. The Cd(Zn)Te crystals integrated into nanoporous alumina have shown to have photoluminescence properties compatible with those of the bulk crystals and planar epitaxial layers. Further investigations are going on to improve the structural quality of Cd(Zn)Te nanocrystals

Multichannel CdZnTe Gamma Ray Spectrometer

International Nuclear Information System (INIS)

Doty, F.P.; Lingren, C. L.; Apotovsky, B. A.; Brunsch, J.; Butler, J. F.; Collins, T.; Conwell, R.L.; Friesenhahn, S.; Gormley, J.; Pi, B.; Zhao, S.; Augustine, F.L.; Bennet, B. A.; Cross, E.; James, R. B.

1998-01-01

A 3 cm 3 multichannel gamma spectrometer for DOE applications is under development by Digirad Corporation. The device is based on a position sensitive detector packaged in a compact multi-chip module (MCM) with integrated readout circuitry. The modular, multichannel design will enable identification and quantitative analysis of radionuclides in extended sources, or sources containing low levels of activity. The MCM approach has the advantages that the modules are designed for imaging applications, and the sensitivity can be arbitrarily increased by increasing the number of pixels, i.e. adding modules to the instrument. For a high sensitivity probe, the outputs for each pixel can be corrected for gain and offset variations, and summed digitally. Single pixel results obtained with discrete low noise readout indicate energy resolution of 3 keV can be approached with currently available CdZnTe. The energy resolution demonstrated to date with MCMs for 511 keV gamma rays is 10 keV

Operation and calibration of the Silicon Drift Detectors of the ALICE experiment during the 2008 cosmic ray data taking period

CERN Document Server

Alessandro, B; Bala, R; Batigne, G; Beolè, S; Biolcati, E; Bock Garcia, N; Bruna, E; Cerello, P; Coli, S; Corrales Morales, Y; Costa, F; Crescio, E; De Remigis, P; Di Liberto, S; Falchieri, D; Feofilov, G; Ferrarese, W; Gandolfi, E; Garcia, C; Gaudichet, L; Giraudo, G; Giubellino, P; Humanic, T J; Igolkin, S; Idzik, M; Kiprich, S K; Kisiel, A; Kolozhvari, A; Kotov, I; Kral, J; Kushpil, S; Kushpil, V; Lea, R; Lisa, M A; Martinez, M I; Marzari Chiesa, A; Masera, M; Masetti, M; Mazza, G; Mazzoni, M A; Meddi, F; Montano Zetina, L M; Monteno, M; Nilsen, B S; Nouais, D; Padilla Cabal, F; Petrácek, V; Poghosyan, M G; Prino, F; Ramello, L; Rashevsky, A; Riccati, L; Rivetti, A S; Senyukov, S; Siciliano, M; Sitta, M; Subieta Vasquez, M A; Sumbera, M L; Toscano, L; Tosello, F; Truesdale, D; Urciuoli, G M; Vacchi, A; Vallero, S; Werbrouck, A; Zampa, G; Zinovjev, G

2010-01-01

The calibration and performance of the Silicon Drift Detector of the ALICE experiment during the 2008 cosmic ray run will be presented. In particular the procedures to monitor the running parameters (baselines, noise, drift speed) are detailed. Other relevant parameters (SOP delay, time-zero, charge calibration) were also determined.

Radial semiconductor drift chambers

International Nuclear Information System (INIS)

Rawlings, K.J.

1987-01-01

The conditions under which the energy resolution of a radial semiconductor drift chamber based detector system becomes dominated by the step noise from the detector dark current have been investigated. To minimise the drift chamber dark current attention should be paid to carrier generation at Si/SiO 2 interfaces. This consideration conflicts with the desire to reduce the signal risetime: a higher drift field for shorter signal pulses requires a larger area of SiO 2 . Calculations for the single shaping and pseudo Gaussian passive filters indicate that for the same degree of signal risetime sensitivity in a system dominated by the step noise from the detector dark current, the pseudo Gaussian filter gives only a 3% improvement in signal/noise and 12% improvement in rate capability compared with the single shaper performance. (orig.)

Correlation of point defects in CdZnTe with charge transport:application to room-temperature X-ray and gamma-ray detectors. Final Technical Report

International Nuclear Information System (INIS)

Giles, Nancy C.

2003-01-01

The primary goal of this project has been to characterize and identify point defects (e.g., impurities, vacancies, vacancy-impurity complexes, etc.) in CdZnTe and determine the mechanisms by which these defects influence the carrier μτproducts. Special attention is given to the role of shallow donors, shallow acceptors, and deeper acceptors. There are two experimental focus areas in the project: (1) liquid-helium photoluminescence (PL) and PL excitation spectroscopy are used to identify and characterize donors and acceptors and to determine zinc molar fraction; and (2) electron paramagnetic resonance (EPR) and photoinduced EPR experiments are performed at liquid-helium temperature to identify paramagnetic point defects and to determine the concentration of these defects. Results from the two experimental focus areas are correlated with detector performance parameters (e.g., electron and hole μτ products), crystal growth conditions, and microstructure analyses

Measurement of electron drift velocities in the mixture of Xe and He for a new high-pressure Xe gamma-ray detector

CERN Document Server

Kobayashi, S; Dmitrenko, V V

2003-01-01

Drift velocities of electrons in a mixture of Xe (20 atm)-He (3 atm) were measured using a cylindrical high-pressure xenon chamber. The drift velocities were found to be greater than 3x10 sup 5 cm/s above the reduced electric field of 2.0x10 sup - sup 1 sup 8 V centre dot cm sup 2 at room temperature, which are close to those in Xe-H sub 2 (0.3%). The mixture of He gas into high-pressure xenon improved the resolving time of detectors because it increased the electron drift velocities. This implies that a high-pressure xenon chamber mixed with sup 3 He instead of He gas operates as a gamma-ray detector sensitive to thermal neutrons. (author)

Conversion electron spectrometry of Pu isotopes with a silicon drift detector

OpenAIRE

Pommé, S.; Paepen, J.; Peräjärvi, K.; Turunen, J.; Pöllänen, R.

2016-01-01

An electron spectrometry set-up was built at IRMM consisting of a vacuum chamber with a moveable source holder and windowless Peltier-cooled silicon drift detector (SDD). The SDD is well suited for measuring low-energy x rays and electrons emitted from thin radioactive sources with low self-absorption. The attainable energy resolution is better than 0.5 keV for electrons of 30 keV. It has been used to measure the conversion electron spectra of three plutonium isotopes, i.e. 238Pu, 239Pu, 240P...

Construction update and drift velocity calibration for the CLAS drift chamber system

International Nuclear Information System (INIS)

Mestayer, M.D.; Barbosa, F.J.; Bonneau, P.; Burtin, E.; Christo, S.; Doolittle, G.; Dytman, S.A.; Gilfoyle, G.P.; Hyde-Wright, C.E.; Klein, A.; Kossov, M.V.; Kuhn, S.E.; Magahiz, R.; Miskimen, R.A.; Murphy, L.Y.; O'Meara, J.E.; Pyron, T.D.; Qin, L.; Raue, B.A.; Schumacher, R.A.; Tuzel, W.; Weinstein, L.B.; Yegneswaran, A.

1995-01-01

We briefly describe the drift chamber system for the CLAS detector at CEBAF, concentrating on the method which will be used to calibrate the drift velocity function. We identify key features of the function which should apply to any small-cell drift chamber geometry in which the cathode and anode surfaces are wires. Using these ideas, we describe a simple method to compensate for variations in the drift velocity function due to environmental changes. (orig.)

Construction update and drift velocity calibration for the CLAS drift chamber system

Energy Technology Data Exchange (ETDEWEB)

Mestayer, M.D. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Barbosa, F.J. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Bonneau, P. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Burtin, E. [University of South Carolina, Columbia, SC (United States); Christo, S. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Doolittle, G. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Dytman, S.A. [University of Pittsburg, Pittsburg, PA (United States); Gilfoyle, G.P. [University of Richmond, Richmond, VA (United States); Hyde-Wright, C.E. [Old Dominion University, Norfolk, VA (United States); Klein, A. [Old Dominion University, Norfolk, VA (United States); Kossov, M.V. [Christopher Newport University, Newport News, VA (United States); Kuhn, S.E. [Old Dominion University, Norfolk, VA (United States); Magahiz, R. [Carnegie-Mellon Univ., Pittsburgh, PA (United States); Miskimen, R.A. [University of Massachussetts, Amherst, MA (United States); Murphy, L.Y. [CE Saclay, Gif sur Yvette (France); O`Meara, J.E. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Pyron, T.D. [Old Dominion University, Norfolk, VA (United States); Qin, L. [Old Dominion University, Norfolk, VA (United States); Raue, B.A. [Old Dominion University, Norfolk, VA (United States); Schumacher, R.A. [Carnegie-Mellon Univ., Pittsburgh, PA (United States); Tuzel, W. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Weinstein, L.B. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Yegneswaran, A. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States)

1995-12-11

We briefly describe the drift chamber system for the CLAS detector at CEBAF, concentrating on the method which will be used to calibrate the drift velocity function. We identify key features of the function which should apply to any small-cell drift chamber geometry in which the cathode and anode surfaces are wires. Using these ideas, we describe a simple method to compensate for variations in the drift velocity function due to environmental changes. (orig.).

Simulation-based evaluation and optimization of a new CdZnTe gamma-camera architecture (HiSens)

International Nuclear Information System (INIS)

Robert, Charlotte; Montemont, Guillaume; Rebuffel, Veronique; Guerin, Lucie; Verger, Loick; Buvat, Irene

2010-01-01

A new gamma-camera architecture named HiSens is presented and evaluated. It consists of a parallel hole collimator, a pixelated CdZnTe (CZT) detector associated with specific electronics for 3D localization and dedicated reconstruction algorithms. To gain in efficiency, a high aperture collimator is used. The spatial resolution is preserved thanks to accurate 3D localization of the interactions inside the detector based on a fine sampling of the CZT detector and on the depth of interaction information. The performance of this architecture is characterized using Monte Carlo simulations in both planar and tomographic modes. Detective quantum efficiency (DQE) computations are then used to optimize the collimator aperture. In planar mode, the simulations show that the fine CZT detector pixelization increases the system sensitivity by 2 compared to a standard Anger camera without loss in spatial resolution. These results are then validated against experimental data. In SPECT, Monte Carlo simulations confirm the merits of the HiSens architecture observed in planar imaging.

Advanced semiconductor detector development: Development of a room-temperature, gamma ray detector using gallium arsenide to develop an electrode detector. Progress report, September 30, 1994--September 29, 1995

International Nuclear Information System (INIS)

Knoll, G.F.

1995-07-01

Devices fabricated from wide bandgap materials that can be operated without cooling suffer from poor energy resolution and are limited to very small volumes; this arises largely from poor hole mobility in compound semiconductors. Three different device configurations are being investigated for possibly overcoming this limitation: buried grid-single carrier devices, trenched single carrier devices, and devices using patterned coplanar electrodes (CdZnTe). In the first, leakage problems were encountered. For the second, a set of specifications has been completed, and electron cyclotron resonance etching will be done at an off-campus facility. For the third, Aurora will supply 3 different CdZnTe detectors. An analytical study was done of the patterned electrode approach

Multiline digital radiographic imager study with synchronization to detector gas ion drift

International Nuclear Information System (INIS)

Peyret, O.

1985-01-01

This direct digital radiographic imager is based on X-ray detection in high pressure rare gas ionization chamber. This linear multidetector, from which scanning radiography is realized, records many lines together. Spatial resolution performance in scanning direction are made sure by scanning synchronization with ion drift in detector. After a physical study and a potential evaluation of its performances on mock-up, a 128 cell prototype has been realized. The first images give validation and limits of such a radiographic process [fr

Measurement of the positron-drift time relation of a high-pressure drift chamber

International Nuclear Information System (INIS)

Pruefert, W.

1989-04-01

As a test of its performance, the measurement of the drift time versus drift distance relation of a high pressure drift chamber using cosmic rays is described. Two multiwire proportional chambers, mounted above and below the detector, are used to define the track of the cosmic particle in the drift chamber. The drift chamber is read out by FADCs (Flash Analog to Digital Converter), and the drift time is determined from the FADC signals by the DOS- (Difference Of Samples) method. The measured drift time versus drift distance relation showed good agreement with the relation, which is expected from the spatial dependence of the electric field and the dependence of the drift velocity on this field. (orig.) [de

An investigation of performance characteristics of a pixellated room-temperature semiconductor detector for medical imaging

Energy Technology Data Exchange (ETDEWEB)

Guerra, P; Santos, A [Centro de Investigacion Biomedica de Bioningenieria, Biomateriales y Nanomedicina, CEEI-Modulo 3, C/ Maria de Luna, 11, 50018 Zaragoza (United States); Darambara, D G, E-mail: pguerra@ciber-bbn.e [Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Fulham Road, London SW3 6JJ (United Kingdom)

2009-09-07

The operation of any semiconductor detector depends on the movement of the charge carriers, which are created within the material when radiation passes through, as a result of energy deposition. The carrier movement in the bulk semiconductor induces charges on the metal electrodes, and therefore a current on the electrodes and the external circuit. The induced charge strongly depends on the material transport parameters as well as the geometrical dimensions of a pixellated semiconductor detector. This work focuses on the performance optimization in terms of energy resolution, detection efficiency and intrinsic spatial resolution of a room-temperature semiconductor pixellated detector based on CdTe/CdZnTe. It analyses and inter-relates these performance figures for various dimensions of CdTe and CdZnTe detectors and for an energy range spanning from x-ray (25 keV) to PET (511 keV) imaging. Monte Carlo simulations, which integrate a detailed and accurate noise model, are carried out to investigate several CdTe/CdZnTe configurations and to determine possible design specifications. Under the considered conditions, the simulations demonstrate the superiority of the CdZnTe over the CdTe in terms of energy resolution and sensitivity in the photopeak. Further, according to the results, the spatial resolution is maximized at high energies and the energy resolution at low energies, while a reasonable detection efficiency is achieved at high energies, with a 1 x 1 x 6 mm{sup 3} CdZnTe pixellated detector.

An investigation of performance characteristics of a pixellated room-temperature semiconductor detector for medical imaging

International Nuclear Information System (INIS)

Guerra, P; Santos, A; Darambara, D G

2009-01-01

The operation of any semiconductor detector depends on the movement of the charge carriers, which are created within the material when radiation passes through, as a result of energy deposition. The carrier movement in the bulk semiconductor induces charges on the metal electrodes, and therefore a current on the electrodes and the external circuit. The induced charge strongly depends on the material transport parameters as well as the geometrical dimensions of a pixellated semiconductor detector. This work focuses on the performance optimization in terms of energy resolution, detection efficiency and intrinsic spatial resolution of a room-temperature semiconductor pixellated detector based on CdTe/CdZnTe. It analyses and inter-relates these performance figures for various dimensions of CdTe and CdZnTe detectors and for an energy range spanning from x-ray (25 keV) to PET (511 keV) imaging. Monte Carlo simulations, which integrate a detailed and accurate noise model, are carried out to investigate several CdTe/CdZnTe configurations and to determine possible design specifications. Under the considered conditions, the simulations demonstrate the superiority of the CdZnTe over the CdTe in terms of energy resolution and sensitivity in the photopeak. Further, according to the results, the spatial resolution is maximized at high energies and the energy resolution at low energies, while a reasonable detection efficiency is achieved at high energies, with a 1 x 1 x 6 mm 3 CdZnTe pixellated detector.

Compensation and trapping in CdZnTe radiation detectors studied by thermoelectric emission spectroscopy, thermally stimulated conductivity, and current-voltage measurements

International Nuclear Information System (INIS)

James, Ralph B.

2000-01-01

In today's commercially available counter-select-grade CdZnTe crystals for radiation detector applications, the thermal ionization energies of the traps and their types, whether electron or hole traps, were measured. The measurements were successfully done using thermoelectric emission spectroscopy (TEES) and thermally stimulated conductivity (TSC). For reliability, the electrical contacts to the sample were found to be very important and, instead of Au Schottky contacts, In Ohmic contacts had to be used. For the filling of the traps, photoexcitation was done at zero bias, at 20K and at wavelengths which gave the maximum bulk photoexcitation for the sample. Between the temperature range from 20 to 400 K, the TSC current was found to be on the order of ∼ 10,000 times or even larger than the TEES current, in agreement with theory, but only TEES could resolve the trap type and was sensitive to the deep traps. Large concentration of hole traps at 0.1 and 0.6 eV were observed and smaller contraction of electron traps at 0.4 eV was seen. These deep traps cause compensation in the material and also cause trapping that degrades the radiation detection measurement

The silicon vertex tracker for star and future applications of silicon drift detectors

International Nuclear Information System (INIS)

Bellwied, Rene

2001-01-01

The Silicon Vertex Tracker (SVT) for the STAR experiment at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory has recently been completed and installed. First data were taken in July 2001. The SVT is based on a novel semi-conductor technology called Silicon Drift Detectors. 216 large area (6 by 6 cm) Silicon wafers were employed to build a three barrel device capable of vertexing and tracking in a high occupancy environment. Its intrinsic radiation hardness, its operation at room temperature and its excellent position resolution (better than 20 micron) in two dimensions with a one dimensional detector readout, make this technology very robust and inexpensive and thus a viable alternative to CCD, Silicon pixel and Silicon strip detectors in a variety of applications from fundamental research in high-energy and nuclear physics to astrophysics to medical imaging. I will describe the development that led to the STAR-SVT, its performance and possible applications for the near future

Compensation scheme for online neutron detection using a Gd-covered CdZnTe sensor

Energy Technology Data Exchange (ETDEWEB)

Dumazert, Jonathan, E-mail: jonathan.dumazert@cea.fr; Coulon, Romain; Kondrasovs, Vladimir; Boudergui, Karim

2017-06-11

The development of portable and personal neutron dosimeters requires compact and efficient radiation sensors. Gd-157, Gd-155 and Cd-113 nuclei present the highest cross-sections for thermal neutron capture among natural isotopes. In order to allow for the exploitation of the low and medium-energy radiative signature of the said captures, the contribution of gamma background radiation, falling into the same energy range, needs to be cancelled out. This paper introduces a thermal neutron detector based on a twin-dense semiconductor scheme. The neutron-sensitive channel takes the form of a Gd-covered CdZnTe crystal, a high density and effective atomic number detection medium. The background compensation will be carried out by means of an identical CdZnTe sensor with a Tb cover. The setting of a hypothesis test aims at discriminating the signal generated by the signature of thermal neutron captures in Gd from statistical fluctuations over the compensation of both independent channels. The measurement campaign conducted with an integrated single-channel chain and two metal Gd and Tb covers, under Cs-137 and Cf-252 irradiations, provides first quantitative results on gamma-rejection and neutron sensitivity. The described study of concept gives grounds for a portable, online-compatible device, operable in conventional to controlled environments.

Performance of Drift-Tube Detectors at High Counting Rates for High-Luminosity LHC Upgrades

CERN Document Server

Bittner, Bernhard; Kortner, Oliver; Kroha, Hubert; Manfredini, Alessandro; Nowak, Sebastian; Ott, Sebastian; Richter, Robert; Schwegler, Philipp; Zanzi, Daniele; Biebel, Otmar; Hertenberger, Ralf; Ruschke, Alexander; Zibell, Andre

2016-01-01

The performance of pressurized drift-tube detectors at very high background rates has been studied at the Gamma Irradiation Facility (GIF) at CERN and in an intense 20 MeV proton beam at the Munich Van-der-Graaf tandem accelerator for applications in large-area precision muon tracking at high-luminosity upgrades of the Large Hadron Collider (LHC). The ATLAS muon drifttube (MDT) chambers with 30 mm tube diameter have been designed to cope with and neutron background hit rates of up to 500 Hz/square cm. Background rates of up to 14 kHz/square cm are expected at LHC upgrades. The test results with standard MDT readout electronics show that the reduction of the drift-tube diameter to 15 mm, while leaving the operating parameters unchanged, vastly increases the rate capability well beyond the requirements. The development of new small-diameter muon drift-tube (sMDT) chambers for LHC upgrades is completed. Further improvements of tracking e?ciency and spatial resolution at high counting rates will be achieved with ...

Deconvolution of ^238,239,240Pu conversion electron spectra measured with a silicon drift detector

DEFF Research Database (Denmark)

Pommé, S.; Marouli, M.; Paepen, J.

2018-01-01

Internal conversion electron (ICE) spectra of thin 238,239,240Pu sources, measured with a windowless Peltier-cooled silicon drift detector (SDD), were deconvoluted and relative ICE intensities were derived from the fitted peak areas. Corrections were made for energy dependence of the full...

Drift chamber

International Nuclear Information System (INIS)

Inagaki, Yosuke

1977-01-01

Drift chamber is becoming an important detector in high energy physics as a precision and fast position detector because of its high spatial resolution and count-rate. The basic principle is that it utilizes the drift at constant speed of electrons ionized along the tracks of charged particles towards the anode wire in the nearly uniform electric field. The method of measuring drift time includes the analog and digital ones. This report describes about the construction of and the application of electric field to the drift chamber, mathematical analysis on the electric field and equipotential curve, derivation of spatial resolution and the factor for its determination, and selection of gas to be used. The performance test of the chamber was carried out using a small test chamber, the collimated β source of Sr-90, and 500 MeV/C electron beam from the 1.3 GeV electron synchrotron in the Institute of Nuclear Study, University of Tokyo. Most chambers to date adopted one dimensional read-out, but it is very advantageous if the two dimensional read-out is feasible with one chamber when the resolution in that direction is low. The typical methods of delay line and charge division for two dimensional read-out are described. The development of digital read-out system is underway, which can process the signal of a large scale drift chamber at high speed. (Wakatsuki, Y.)

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

International Nuclear Information System (INIS)

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

2011-01-01

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

Cadmium Manganese Telluride (Cd1-xMnxTe): A potential material for room-temperature radiation detectors

Energy Technology Data Exchange (ETDEWEB)

Hossain, A.; Cui, Y.; Bolotnikov, A.; Camarda, G.; Yang, G.; Kim, K-H.; Gul, R.; Xu, L.; Li, L.; Mycielski, A.; and James, R.B.

2010-07-11

Cadmium Manganese Telluride (CdMnTe) recently emerged as a promising material for room-temperature X- and gamma-ray detectors. It offers several potential advantages over CdZnTe. Among them is its optimal tunable band gap ranging from 1.7-2.2 eV, and its relatively low (< 50%) content of Mn compared to that of Zn in CdZnTe that assures this favorable band-gap range. Another important asset is the segregation coefficient of Mn in CdTe that is approximately unity compared to 1.35 for Zn in CdZnTe, so ensuring the homogenous distribution of Mn throughout the ingot; hence, a large-volume stoichiometric yield is attained. However, some materials issues primarily related to the growth process impede the production of large, defect-free single crystals. The high bond-ionicity of CdMnTe entails a higher propensity to crystallize into a hexagonal structure rather than to adopt the expected zinc-blend structure, which is likely to generate twins in the crystals. In addition, bulk defects generate in the as-grown crystals due to the dearth of high-purity Mn, which yields a low-resistivity material. In this presentation, we report on our observations of such material defects in current CdMnTe materials, and our evaluation of its potential as an alternative detector material to the well-known CdZnTe detectors. We characterized the bulk defects of several indium- and vanadium-doped Cd1-xMnxTe crystals by using several advanced techniques, viz., micro-scale mapping, white-beam x-ray diffraction/reflection topography, and chemical etching. Thereafter, we fabricated some detectors from selected CdMnTe crystals, characterized their electrical properties, and tested their performance as room-temperature X- and gamma-ray detectors. Our experimental results indicate that CdMnTe materials could well prove to become a viable alternative in the near future.

A pixellated gamma-camera based on CdTe detectors clinical interests and performances

CERN Document Server

Chambron, J; Eclancher, B; Scheiber, C; Siffert, P; Hage-Ali, M; Regal, R; Kazandjian, A; Prat, V; Thomas, S; Warren, S; Matz, R; Jahnke, A; Karman, M; Pszota, A; Németh, L

2000-01-01

A mobile gamma camera dedicated to nuclear cardiology, based on a 15 cmx15 cm detection matrix of 2304 CdTe detector elements, 2.83 mmx2.83 mmx2 mm, has been developed with a European Community support to academic and industrial research centres. The intrinsic properties of the semiconductor crystals - low-ionisation energy, high-energy resolution, high attenuation coefficient - are potentially attractive to improve the gamma-camera performances. But their use as gamma detectors for medical imaging at high resolution requires production of high-grade materials and large quantities of sophisticated read-out electronics. The decision was taken to use CdTe rather than CdZnTe, because the manufacturer (Eurorad, France) has a large experience for producing high-grade materials, with a good homogeneity and stability and whose transport properties, characterised by the mobility-lifetime product, are at least 5 times greater than that of CdZnTe. The detector matrix is divided in 9 square units, each unit is composed ...

Evaluation of a wavelet-based compression algorithm applied to the silicon drift detectors data of the ALICE experiment at CERN

International Nuclear Information System (INIS)

Falchieri, Davide; Gandolfi, Enzo; Masotti, Matteo

2004-01-01

This paper evaluates the performances of a wavelet-based compression algorithm applied to the data produced by the silicon drift detectors of the ALICE experiment at CERN. This compression algorithm is a general purpose lossy technique, in other words, its application could prove useful even on a wide range of other data reduction's problems. In particular the design targets relevant for our wavelet-based compression algorithm are the following ones: a high-compression coefficient, a reconstruction error as small as possible and a very limited execution time. Interestingly, the results obtained are quite close to the ones achieved by the algorithm implemented in the first prototype of the chip CARLOS, the chip that will be used in the silicon drift detectors readout chain

Simulation of drift dynamics of arbitrary carrier distributions in complex semiconductor detectors

CERN Document Server

De Castro Manzano, Pablo

2014-01-01

An extensible open-source C++ software for the simulation of elec- trons and holes drift in semiconductor detectors of complex geometries has been developed in order to understand transient currents and charge collection efficiencies of arbitrary charge distributions. The simulation is based on Ramo’s theorem formalism to obtain induced currents in the electrodes. Efficient open source C++ numerical libraries are used to ob- tain the electric and weighting field using finite-element methods and to simulate the carrier transport. A graphical user interface is also provided. The tool has already been proved useful to model laser induced transient currents

Low-energy CZT detector array for the ASIM mission

DEFF Research Database (Denmark)

Cenkeramaddi, Linga Reddy; Genov, Georgi; Kohfeldt, Anja

2012-01-01

In this article we introduce the low-energy CZT (CdZnTe) 16 384-pixel detector array on-board the Atmosphere Space Interaction Monitor (ASIM), funded by the European Space Agency. This detector is a part of the larger Modular X-and Gamma-ray sensor (MXGS). The CZT detector array is sensitive...... to photons with energies between 15 keV and 400 keV. The principal objective of the MXGS instrument is to detect Terrestrial Gamma ray Flashes (TGFs), which are related to thunderstorm activity. The concept of the detector array is presented, together with brief descriptions of its mechanical structure...

Construction and operation of a drift-collection calorimeter

International Nuclear Information System (INIS)

Ambats, I.; Ayres, D.S.; Dawson, J.W.

1984-01-01

Large areas planar drift chambers with long drift distance (up to 50 cm) have been developed for possible use in the new Soudan 2 nucleon decay detector. Design goals included fine sampling to determine the topology of complex events with several low-energy tracks. The large scale of the experiment (> 1000 metric tons) required large area inexpensive chambers, which also had good position resolution and multi-track separation. The chambers were to be installed between thin sheets of steel to form a finegrained detector. A second goal was the sampling of dE/dx with each position measurement, in order to determine the direction and particle identity of each track. In this paper we report on the construction and operation of a prototype dectector consisting of 50 chambers, separated by 3 mm-thick steel plates. Readout of drift time and pulse height from anode wires and an orthogonal grid of bussed cathode pads utilized 6-bit flash ADC's. This application of the drift-collection calorimeter technique to a nucleon decay detector follows the investigation by a number of groups of calorimeters for high energy detectors based on long drifting

Study of a new architecture of gamma cameras with Cd/ZnTe/CdTe semiconductors; Etude d'une nouvelle architecture de gamma camera a base de semi-conducteurs CdZnTe /CdTe

Energy Technology Data Exchange (ETDEWEB)

Guerin, L

2007-11-15

This thesis studies new semi conductors for gammas cameras in order to improve the quality of image in nuclear medicine. The chapter 1 reminds the general principle of the imaging gamma, by describing the radiotracers, the channel of detection and the types of Anger gamma cameras acquisition. The physiological, physical and technological limits of the camera are then highlighted, to better identify the needs of future gamma cameras. The chapter 2 is dedicated to a bibliographical study. At first, semi-conductors used in imaging gamma are presented, and more particularly semi-conductors CDTE and CdZnTe, by distinguishing planar detectors and monolithic pixelated detectors. Secondly, the classic collimators of the gamma cameras, used in clinical routine for the most part of between them, are described. Their geometry is presented, as well as their characteristics, their advantages and their inconveniences. The chapter 3 is dedicated to a state of art of the simulation codes dedicated to the medical imaging and the methods of reconstruction in imaging gamma. These states of art allow to introduce the software of simulation and the methods of reconstruction used within the framework of this thesis. The chapter 4 presents the new architecture of gamma camera proposed during this work of thesis. It is structured in three parts. The first part justifies the use of semiconducting detectors CdZnTe, in particular the monolithic pixelated detectors, by bringing to light their advantages with regard to the detection modules based on scintillator. The second part presents gamma cameras to base of detectors CdZnTe (prototypes or commercial products) and their associated collimators, as well as the interest of an association of detectors CdZnTe in the classic collimators. Finally, the third part presents in detail the HiSens architecture. The chapter 5 describes both software of simulation used within the framework of this thesis to estimate the performances of the Hi

An electrodeless drift chamber

International Nuclear Information System (INIS)

Allison, J.; Barlow, R.J.; Bowdery, C.K.; Duerdoth, I.; Rowe, P.G.

1982-01-01

We describe a chamber in which the drift field is controlled by the deposition of electrostatic charge on an insulating surface. The chamber operates with good efficiency and precision for observed drift distances of up to 45 cm, promises to be extremely robust and adaptable and offers a very cheap way of making particle detectors. (orig.)

Simulations of the x-ray imaging capabilities of the silicon drift detectors (SDD) for the LOFT wide-field monitor

DEFF Research Database (Denmark)

Evangelista, Y.; Campana, R.; Del Monte, E.

2012-01-01

Detector (LAD), carrying an unprecedented effective area of 10 m^2, is complemented by a coded-mask Wide Field Monitor, in charge of monitoring a large fraction of the sky potentially accessible to the LAD, to provide the history and context for the sources observed by LAD and to trigger its observations...... on their most interesting and extreme states. In this paper we present detailed simulations of the imaging capabilities of the Silicon Drift Detectors developed for the LOFT Wide Field Monitor detection plane. The simulations explore a large parameter space for both the detector design and the environmental...

Construction and test of a silicon drift chamber

International Nuclear Information System (INIS)

Holl, P.

1985-06-01

The present thesis presents the first fully applicable silicon detectors which work as drift chambers. Four different types of detectors were constructed. By a suitable geometry and electronic lay-out one- and two-dimensional position measurements were made possible. Chapter 2 describes function and construction of the detectors, chapter 3 their fabrication process. In chapter 4 construction and results of the test of a silicon drift chamber under laboratory conditions are described. By variation of the applied voltages the optimal operational conditions could be determined and material properties of the silicon, as for instance the electron mobility measured. A position resolution better than 5 μm at a drift length up to 4 mm was reached. Chapter 5 presents the results of the test of a silicon drift chamber under real experimental conditions in a particle beam of the super proton synchroton (SPS) of CERN. The best position resolution measured there is 10 μm. Chapter 6 summarizes the obtained results and discusses finally application possibilities and improvement proposals for silicon drift chambers. (orig./HSI) [de

Fine-scale spatial response of CdZnTe radiation detectors

International Nuclear Information System (INIS)

Brunett, B.A.; Van Scyoc, J.M.; Hilton, N.R.; Lund, J.C.; James, R.B.; Schlesinger, T.E.

1998-01-01

Several studies have suggested that the uniformity of Cadmium Zinc Telluride (CZT) detectors play an important role in their performance when operated as gamma-ray spectrometers. However the detailed gamma response of simple planar detectors as a function of position over the device area is largely unknown. To address this issue the authors have built a system capable of measuring the detector response with a resolution of ∼250 (micro)m. The system consists of a highly collimated (∼200 (micro)m) photon source (<150 kev) scanned over the detector using a computer controlled two-axis translation stage. Fifteen samples configured as planar detectors were examined with the new apparatus. The material grade of the detectors examined varied from counter to select discriminator. Two classes of spatial response variation were observed and are presented here. Infrared (IR) transmission images were also acquired for each sample and correlation between features in the pulse height spectrum and crystalline defects were observed

Silicon drift detectors for high resolution room temperature X-ray spectroscopy

International Nuclear Information System (INIS)

Lechner, P.; Eckbauer, S.; Hauff, D.; Strueder, L.; Gatti, E.; Longoni, A.; Sampietro, M.

1996-01-01

New cylindrical silicon drift detectors have been designed, fabricated and tested. They comprise an integrated on-chip amplifier system with continuous reset, on-chip voltage divider, electron accumulation layer stabilizer, large area, homogeneous radiation entrance window and a drain for surface generated leakage current. The test of the 3.5 mm 2 large individual devices, which have also been grouped together to form a sensitive area up to 21 mm 2 have shown the following spectroscopic results: at room temperature (300 K) the devices have shown a full width at half maximum at the Mn Kα line of a radioactive 55 Fe source of 225 eV with shaping times of 250 to 500 ns. At -20 C the resolution improves to 152 eV at 2 μs Gaussian shaping. At temperatures below 200 K the energy resolution is below 140 eV. With the implementation of a digital filtering system the resolution approaches 130 eV. The system was operated with count rates up to 800 000 counts per second and per readout node, still conserving the spectroscopic qualities of the detector system. (orig.)

Conversion electron spectrometry of Pu isotopes with a silicon drift detector.

Science.gov (United States)

Pommé, S; Paepen, J; Peräjärvi, K; Turunen, J; Pöllänen, R

2016-03-01

An electron spectrometry set-up was built at IRMM consisting of a vacuum chamber with a moveable source holder and windowless Peltier-cooled silicon drift detector (SDD). The SDD is well suited for measuring low-energy x rays and electrons emitted from thin radioactive sources with low self-absorption. The attainable energy resolution is better than 0.5keV for electrons of 30keV. It has been used to measure the conversion electron spectra of three plutonium isotopes, i.e. (238)Pu, (239)Pu, (240)Pu, as well as (241)Am (being a decay product of (241)Pu). The obtained mixed x-ray and electron spectra are compared with spectra obtained with a close-geometry set-up using another SDD in STUK and spectra measured with a Si(Li) detector at IRMM. The potential of conversion electron spectrometry for isotopic analysis of mixed plutonium samples is investigated. With respect to the (240)Pu/(239)Pu isotopic ratio, the conversion electron peaks of both isotopes are more clearly separated than their largely overlapping peaks in alpha spectra. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Laboratory Course on Drift Chambers

International Nuclear Information System (INIS)

Garcia-Ferreira, Ix-B.; Garcia-Herrera, J.; Villasenor, L.

2006-01-01

Drift chambers play an important role in particle physics experiments as tracking detectors. We started this laboratory course with a brief review of the theoretical background and then moved on to the the experimental setup which consisted of a single-sided, single-cell drift chamber. We also used a plastic scintillator paddle, standard P-10 gas mixture (90% Ar, 10% CH4) and a collimated 90Sr source. During the laboratory session the students performend measurements of the following quantities: a) drift velocities and their variations as function of the drift field; b) gas gains and c) diffusion of electrons as they drifted in the gas

Conceptual design report for the SDC barrel and intermediate muon detectors based on a jet-type drift chamber

International Nuclear Information System (INIS)

Arai, Y.; Funahashi, Y.; Higashi, Y.

1992-04-01

We propose a jet-type drift chamber for the barrel and intermediate muon detectors of SDC. The chamber system consists of large multiwire drift chambers having a simple box-type frame structure: 2. 5 x 0.4 m 2 in cross section and maximum 9 m in length. A chamber module consists of double layers of small jet cells. The drift cell is composed of a wire plane, including 3 sense wires, and cathode plates parallel to the wire plane. The two layers in a chamber are staggered to each other by half a cell width. The jet cell is tilted such that its principle axis points to the interaction point. Such an arrangement, together with a constant drift velocity of the jet cell, allows us to design a simple and powerful trigger system for high momentum muons utilizing a drift time sum between a pair of staggered cells. The multi-hit capability will be helpful to distinguish high momentum muon tracks from associated electromagnetic debris as has been demonstrated by the Fermilab beam test T816. The maximum drift time fulfills the SDC requirement. A preliminary FEM analysis of the chamber module verified the excellent structural stiffness. It makes the support structure and the alignment system relatively simple. These features will reduce the total cost as well as ensure a good performance of the chamber system. (J.P.N.)

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

International Nuclear Information System (INIS)

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

1987-10-01

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

The JADE muon detector

International Nuclear Information System (INIS)

Allison, J.; Armitage, J.C.M.; Baines, J.T.M.; Ball, A.H.; Bamford, G.; Barlow, R.J.; Bowdery, C.K.; Chrin, J.T.M.; Duerdoth, I.P.; Glendinning, I.; Greenshaw, T.; Hassard, J.F.; Hill, P.; King, B.T.; Loebinger, F.K.; Macbeth, A.A.; McCann, H.; Mercer, D.; Mills, H.E.; Murphy, P.G.; Prosper, H.B.; Rowe, P.; Stephens, K.

1985-01-01

The JADE muon detector consists of 618 planar drift chambers interspersed between layers of hadron absorber. This paper gives a detailed description of the construction and operation of the detector as a whole and discusses the properties of the drift chambers. The muon detector has been operating successfully at PETRA for five years. (orig.)

Development of a time-to-digital converter ASIC for the upgrade of the ATLAS Monitored Drift Tube detector

Science.gov (United States)

Wang, Jinhong; Liang, Yu; Xiao, Xiong; An, Qi; Chapman, John W.; Dai, Tiesheng; Zhou, Bing; Zhu, Junjie; Zhao, Lei

2018-02-01

The upgrade of the ATLAS muon spectrometer for the high-luminosity LHC requires new trigger and readout electronics for various elements of the detector. We present the design of a time-to-digital converter (TDC) ASIC prototype for the ATLAS Monitored Drift Tube (MDT) detector. The chip was fabricated in a GlobalFoundries 130 nm CMOS technology. Studies indicate that its timing and power dissipation characteristics meet the design specifications, with a timing bin variation of ±40 ps for all 48 TDC slices and a power dissipation of about 6.5 mW per slice.

Construction and test of the analog electronics for the planar drift chambers of the ZEUS detector

International Nuclear Information System (INIS)

Meyer, J.

1990-03-01

The front-end-electronics for the planar drift chambers. FTD/RTD, of the ZEUS detector, developed by Siegen University, has been tested in their performance together with a FTD testcell. This cell was operated under new high voltage conditions and showed a gas gain of G ≅ 1x10 4 . The electronics, consisting of a preamplifier, a 45 m signal cable and a postamplifier with the ability of puls shaping, had to be matched to the dynamic input range of the FADS's. This led to a completely new design of the postamplifier. Signal crosstalk in the drift cell can distort the original puls shape and possibly leads to a wrong trace reconstruction. Measurements of the crosstalk showed a 10% effect, that can be reduced by a passive crosstalk compensation to less than 5%. (orig.) [de

ATLAS Muon Drift Tube Electronics

CERN Document Server

Arai, Y; Beretta, M; Boterenbrood, H; Brandenburg, G W; Ceradini, F; Chapman, J W; Dai, T; Ferretti, C; Fries, T; Gregory, J; Guimarães da Costa, J; Harder, S; Hazen, E; Huth, J; Jansweijer, P P M; Kirsch, L E; König, A C; Lanza, A; Mikenberg, G; Oliver, J; Posch, C; Richter, R; Riegler, W; Spiriti, E; Taylor, F E; Vermeulen, J; Wadsworth, B; Wijnen, T A M

2008-01-01

This paper describes the electronics used for the ATLAS monitored drift tube (MDT) chambers. These chambers are the main component of the precision tracking system in the ATLAS muon spectrometer. The MDT detector system consists of 1,150 chambers containing a total of 354,000 drift tubes. It is capable of measuring the sagitta of muon tracks to an accuracy of 60 microns, which corresponds to a momentum accuracy of about 10% at pT = 1 TeV. The design and performance of the MDT readout electronics as well as the electronics for controlling, monitoring and powering the detector will be discussed. These electronics have been extensively tested under simulated running conditions and have undergone radiation testing certifying them for more than 10 years of LHC operation. They are now installed on the ATLAS detector and are operating during cosmic ray commissioning runs.

Recent Developments on the Silicon Drift Detector readout scheme for the ALICE Inner Tracking System

CERN Document Server

Mazza, G; Bonazzola, G C; Bonvicini, V; Cavagnino, D; Cerello, P G; De Remigis, P; Falchieri, D; Gabrielli, A; Gandolfi, E; Giubellino, P; Hernández, R; Masetti, M; Montaño-Zetina, L M; Nouais, D; Rashevsky, A; Rivetti, A; Tosello, F

1999-01-01

Proposal of abstract for LEB99, Snowmass, Colorado, 20-24 September 1999Recent developments of the Silicon Drift Detector (SDD) readout system for the ALICE Experiment are presented. The foreseen readout system is based on 2 main units. The first unit consists of a low noise preamplifier, an analog memory which continuously samples the amplifier output, an A/D converter and a digital memory. When the trigger signal validates the analog data, the ADCs convert the samples into a digital form and store them into the digital memory. The second unit performs the zero suppression/data compression operations. In this paper the status of the design is presented, together with the test results of the A/D converter, the multi-event buffer and the compression unit prototype.Summary:In the Inner Tracker System (ITS) of the ALICE experiment the third and the fourth layer of the detectors are SDDs. These detectors provide the measurement of both the energy deposition and the bi-dimensional position of the track. In terms o...

Electron Drift Properties in High Pressure Gaseous Xenon

Energy Technology Data Exchange (ETDEWEB)

Simón, A.; et al.

2018-04-05

Gaseous time projection chambers (TPC) are a very attractive detector technology for particle tracking. Characterization of both drift velocity and diffusion is of great importance to correctly assess their tracking capabilities. NEXT-White is a High Pressure Xenon gas TPC with electroluminescent amplification, a 1:2 scale model of the future NEXT-100 detector, which will be dedicated to neutrinoless double beta decay searches. NEXT-White has been operating at Canfranc Underground Laboratory (LSC) since December 2016. The drift parameters have been measured using $^{83m}$Kr for a range of reduced drift fields at two different pressure regimes, namely 7.2 bar and 9.1 bar. The results have been compared with Magboltz simulations. Agreement at the 5% level or better has been found for drift velocity, longitudinal diffusion and transverse diffusion.

A drift chamber constructed of aluminized mylar tubes

Science.gov (United States)

Baringer, P.; Jung, C.; Ogren, H. O.; Rust, D. R.

1987-03-01

A thin reliable drift chamber has been constructed to be used near the interaction point of the PEP storage ring in the HRS detector. It is composed of individual drift tubes with aluminized mylar walls.

The front-end analog and digital signal processing electronics for the drift chambers of the Stanford Large Detector

International Nuclear Information System (INIS)

Haller, G.M.; Freytag, D.R.; Fox, J.; Olsen, J.; Paffrath, L.; Yim, A.; Honma, A.

1990-10-01

The front-end signal processing electronics for the drift-chambers of the Stanford Large Detector (SLD) at the Stanford Linear Collider is described. The system is implemented with printed-circuit boards which are shaped for direct mounting on the detector. Typically, a motherboard comprises 64 channels of transimpedance amplification and analog waveform sampling, A/D conversion, and associated control and readout circuitry. The loaded motherboard thus forms a processor which records low-level wave forms from 64 detector channels and transforms the information into a 64 k-byte serial data stream. In addition, the package performs calibration functions, measures leakage currents on the wires, and generates wire hit patterns for triggering purposes. The construction and operation of the electronic circuits utilizing monolithic, hybridized, and programmable components are discussed

A drift chamber constructed of aluminized mylar tubes

International Nuclear Information System (INIS)

Baringer, P.; Jung, C.; Ogren, H.O.; Rust, D.R.

1987-01-01

A thin reliable drift chamber has been constructed to be used near the interaction point of the PEP storage ring in the HRS detector. It is composed of individual drift tubes with aluminized mylar walls. (orig.)

A compact and modular x- and gamma-ray detector with a CsI scintillator and double-readout Silicon Drift Detectors

Science.gov (United States)

Campana, R.; Fuschino, F.; Labanti, C.; Marisaldi, M.; Amati, L.; Fiorini, M.; Uslenghi, M.; Baldazzi, G.; Bellutti, P.; Evangelista, Y.; Elmi, I.; Feroci, M.; Ficorella, F.; Frontera, F.; Picciotto, A.; Piemonte, C.; Rachevski, A.; Rashevskaya, I.; Rignanese, L. P.; Vacchi, A.; Zampa, G.; Zampa, N.; Zorzi, N.

2016-07-01

A future compact and modular X and gamma-ray spectrometer (XGS) has been designed and a series of proto- types have been developed and tested. The experiment envisages the use of CsI scintillator bars read out at both ends by single-cell 25 mm2 Silicon Drift Detectors. Digital algorithms are used to discriminate between events absorbed in the Silicon layer (lower energy X rays) and events absorbed in the scintillator crystal (higher energy X rays and -rays). The prototype characterization is shown and the modular design for future experiments with possible astrophysical applications (e.g. for the THESEUS mission proposed for the ESA M5 call) are discussed.

Focal plane detector for QDD spectrography in Institute of Nuclear Study and detector for SMART 2nd focal plane in RIKEN

Energy Technology Data Exchange (ETDEWEB)

Fuchi, Yoshihide [Tokyo Univ., Tanashi (Japan). Inst. for Nuclear Study

1996-09-01

The focal plane detector for QDD spectrography in Institute of Nuclear Study was composed of drift space and a proportional counter tube, and the latter is composed of position detector and two delta E detector for recognizing the particles. In this detector, a uniform parallel electric field can be obtained by placing a guard plate at the same height as that of a drift plate outer place of the detector. On the other hand, the detector for SMART 2nd focal plate in RIKEN is composed of drift space and a single wire proportional counter, and has two cathode read out single wire drift counters set so as to hold the focal plane. (G.K.)

Sealed drift tube cosmic ray veto counters

International Nuclear Information System (INIS)

Rios, R.; Tatar, E.; Bacon, J.D.; Bowles, T.J.; Hill, R.; Green, J.A.; Hogan, G.E.; Ito, T.M.; Makela, M.; Morris, C.L.; Mortenson, R.; Pasukanics, F.E.; Ramsey, J.; Saunders, A.; Seestrom, S.J.; Sondheim, W.E.; Teasdale, W.; Saltus, M.; Back, H.O.; Cottrell, C.R.

2011-01-01

We describe a simple drift tube counter that has been used as a cosmic ray veto for the UCNA experiment, a first-ever measurement of the neutron beta-asymmetry using ultra-cold neutrons. These detectors provide an inexpensive alternative to more conventional scintillation detectors for large area cosmic ray anticoincidence detectors.

Diffusion and drift of charges in semiconductor detectors

International Nuclear Information System (INIS)

Meidinger, N.

1991-01-01

For this analysis, a fully depleteable pn-CCD (a novel, energy and local resolution semiconductor using the drift chamber principle) has been tested for verification at different temperatures, photon energies, and drift times, including theoretical calculations. Experimental results are in good agreement with calculated data, and deviations (≤11%) have been understood to an extent that proposals can be made for improving the accuracy. Charge splitting has been found to be reduced in the case of reduced charge collecting areas, i.e. for example at lower temperatures, or with shorter drift times. This effect is also reduced in the case of larger charge collecting areas (pixels). With the given topology of the cell structure, the charge splitting can be much more strongly suppressed as compared to other X-ray CCD design types. (orig.) [de

ATLAS Muon Drift Tube Electronics

Energy Technology Data Exchange (ETDEWEB)

Arai, Y [KEK, High Energy Accelerator Research Organisation, Tsukuba (Japan); Ball, B; Chapman, J W; Dai, T; Ferretti, C; Gregory, J [University of Michigan, Department of Physics, Ann Arbor, MI (United States); Beretta, M [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Boterenbrood, H; Jansweijer, P P M [Nikhef National Institute for Subatomic Physics, Amsterdam (Netherlands); Brandenburg, G W; Fries, T; Costa, J Guimaraes da; Harder, S; Huth, J [Harvard University, Laboratory for Particle Physics and Cosmology, Cambridge, MA (United States); Ceradini, F [INFN Roma Tre and Universita Roma Tre, Dipartimento di Fisica, Roma (Italy); Hazen, E [Boston University, Physics Department, Boston, MA (United States); Kirsch, L E [Brandeis University, Department of Physics, Waltham, MA (United States); Koenig, A C [Radboud University Nijmegen/Nikhef, Dept. of Exp. High Energy Physics, Nijmegen (Netherlands); Lanza, A [INFN Pavia, Pavia (Italy); Mikenberg, G [Weizmann Institute of Science, Department of Particle Physics, Rehovot (Israel)], E-mail: brandenburg@physics.harvard.edu (and others)

2008-09-15

This paper describes the electronics used for the ATLAS monitored drift tube (MDT) chambers. These chambers are the main component of the precision tracking system in the ATLAS muon spectrometer. The MDT detector system consists of 1,150 chambers containing a total of 354,000 drift tubes. It is capable of measuring the sagitta of muon tracks to an accuracy of 60 {mu}m, which corresponds to a momentum accuracy of about 10% at p{sub T}= 1 TeV. The design and performance of the MDT readout electronics as well as the electronics for controlling, monitoring and powering the detector will be discussed. These electronics have been extensively tested under simulated running conditions and have undergone radiation testing certifying them for more than 10 years of LHC operation. They are now installed on the ATLAS detector and are operating during cosmic ray commissioning runs.

The CLEO III drift chamber

CERN Document Server

Peterson, D; Briere, R A; Chen, G; Cronin-Hennessy, D; Csorna, S; Dickson, M; Dombrowski, S V; Ecklund, K M; Lyon, A; Marka, S; Meyer, T O; Patterson, J R; Sadoff, A; Thies, P; Thorndike, E H; Urner, D

2002-01-01

The CLEO group at the Cornell Electron Storage Ring has constructed and commissioned a new central drift chamber. With 9796 cells arranged in 47 layers ranging in radius from 13.2 to 79 cm, the new drift chamber has a smaller outer radius and fewer wires than the drift chamber it replaces, but allows the CLEO tracking system to have improved momentum resolution. Reduced scattering material in the chamber gas and in the inner skin separating the drift chamber from the silicon vertex detector provides a reduction of the multiple scattering component of the momentum resolution and an extension of the usable measurement length into the silicon. Momentum resolution is further improved through quality control in wire positioning and symmetry of the electric fields in the drift cells which have provided a reduction in the spatial resolution to 88 mu m (averaged over the full drift range).

Drift chamber tracking with neural networks

International Nuclear Information System (INIS)

Lindsey, C.S.; Denby, B.; Haggerty, H.

1992-10-01

We discuss drift chamber tracking with a commercial log VLSI neural network chip. Voltages proportional to the drift times in a 4-layer drift chamber were presented to the Intel ETANN chip. The network was trained to provide the intercept and slope of straight tracks traversing the chamber. The outputs were recorded and later compared off line to conventional track fits. Two types of network architectures were studied. Applications of neural network tracking to high energy physics detector triggers is discussed

An X-ray computed tomography demonstrator using a CZT solid-state detector

International Nuclear Information System (INIS)

Claesson, Th.; Kerek, A.; Molnar, J.; Novak, D.

2002-01-01

A demonstrator of Computed Tomography (CT) has been designed and built for educational purposes. The system is based on a solid-state CdZnTe detector and a standard PC. The mechanics of the system is controlled and data is acquired by programs written in LabVIEW. CT images are reconstructed using MATLAB programs

Picosecond UV single photon detectors with lateral drift field: Concept and technologies

Energy Technology Data Exchange (ETDEWEB)

Yakimov, M.; Oktyabrsky, S.; Murat, P.

2015-09-01

Group III–V semiconductor materials are being considered as a Si replacement for advanced logic devices for quite some time. Advances in III–V processing technologies, such as interface and surface passivation, large area deep submicron lithography with high-aspect ratio etching primarily driven by the metal-oxide-semiconductor field-effect transistor development can also be used for other applications. In this paper we will focus on photodetectors with the drift field parallel to the surface. We compare the proposed concept to the state-of-the-art Si-based technology and discuss requirements which need to be satisfied for such detectors to be used in a single photon counting mode in blue and ultraviolet spectral region with about 10 ps photon timing resolution essential for numerous applications ranging from high-energy physics to medical imaging.

Electrical properties of Au/CdZnTe/Au detectors grown by the boron oxide encapsulated Vertical Bridgman technique

Energy Technology Data Exchange (ETDEWEB)

Turturici, A.A. [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy); Abbene, L., E-mail: leonardo.abbene@unipa.it [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy); Gerardi, G. [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy); Benassi, G. [due2lab s.r.l., Via Paolo Borsellino 2, Scandiano, 42019 Reggio Emilia (Italy); Bettelli, M.; Calestani, D. [IMEM/CNR, Parco Area delle Scienze 37/A, Parma 43100 (Italy); Zambelli, N. [due2lab s.r.l., Via Paolo Borsellino 2, Scandiano, 42019 Reggio Emilia (Italy); Raso, G. [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy); Zappettini, A. [IMEM/CNR, Parco Area delle Scienze 37/A, Parma 43100 (Italy); Principato, F. [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy)

2016-09-11

In this work we report on the results of electrical characterization of new CdZnTe detectors grown by the Boron oxide encapsulated Vertical Bridgman technique (B-VB), currently produced at IMEM-CNR (Parma, Italy). The detectors, with gold electroless contacts, have different thicknesses (1 and 2.5 mm) and the same electrode layout, characterized by a central anode surrounded by a guard-ring electrode. Investigations on the charge transport mechanisms and the electrical contact properties, through the modeling of the measured current–voltage (I–V) curves, were performed. Generally, the detectors are characterized by low leakage currents at high bias voltages even at room temperature: 34 nA/cm{sup 2} (T=25 °C) at 10,000 V/cm, making them very attractive for high flux X-ray measurements, where high bias voltage operation is required. The Au/CdZnTe barrier heights of the devices were estimated by using the interfacial layer-thermionic-diffusion (ITD) model in the reverse bias voltage range. Comparisons with CdZnTe detectors, grown by Traveling Heater Method (THM) and characterized by the same electrode layout, deposition technique and resistivity, were also performed.

The OPAL vertex drift chamber

International Nuclear Information System (INIS)

Carter, J.R.; Elcombe, P.A.; Hill, J.C.; Roach, C.M.; Armitage, J.C.; Carnegie, R.K.; Estabrooks, P.; Hemingway, R.; Karlen, D.; McPherson, A.; Pinfold, J.; Roney, J.M.; Routenburg, P.; Waterhouse, J.; Hargrove, C.K.; Klem, D.; Oakham, F.G.; Carter, A.A.; Jones, R.W.L.; Lasota, M.M.B.; Lloyd, S.L.; Pritchard, T.W.; Wyatt, T.R.

1990-01-01

A high precision vertex drift chamber has been installed in the OPAL experiment at LEP. The design of the chamber and the associated readout electronics is described. The performance of the system has been studied using cosmic ray muons and the results of these studies are presented. A space resolution of 50 μm in the drift direction is obtained using the OPAL central detector gas mixture at 4 bar. (orig.)

Improvement of the drift chamber system in the SAPHIR detector and first measurements of the Φ meson production at threshold

International Nuclear Information System (INIS)

Scholmann, J.N.

1996-09-01

The SAPHIR detector at ELSA enables the measurement of photon induced Φ meson production from threshold up to 3 GeV in the full kinematical range. A considerable improvement of the drift chamber system is a precondition of gaining the necessary data rate in an acceptable time. The research focuses attention on the choice of the chamber gas and on a different mechanical construction, so as to minimize the negative influences of the photon beam crossing the sensitive volume of the drift chamber system. In addition, first preliminary results of the total and the differential cross section for the Φ meson production close to threshold were evaluated. (orig.)

Test and commissioning of the CARLOS control boards for the ALICE Silicon Drift Detectors

CERN Document Server

Alessandro, Bruno; Beolè, S; Coli, S; Costa, F; De Remigis, P; Falchieri, Davide; Gandolfi, Enzo; Giraudo, G; Giubellino, P; Kral, J F; Masetti, Massimo; Mazza, G; Rashevsky, A; Riccati, Lodovico; Rivetti, A; Senyukov, S; Toscano, Letterio; Tosello, F; Wheadon, R

2007-01-01

This paper presents the test strategy employed during the installation of the CARLOS end ladder boards developed for the Silicon Drift Detectors (SDD) of ALICE. Each CARLOS board compresses the data provided by the front-end electronics of one SDD and sends them via an optical link of 800 Mbit/s to the data concentrator card (CARLOSrx) located in the counting room. The paper describes the integration of the CARLOS boards in the final SDD system, including its cooling and mechanical support, the power supply distribution and the optical interconnections. The results of the tests performed after each step of the installation sequence are reported.

Laser ablation in CdZnTe crystal due to thermal self-focusing: Secondary phase hydrodynamic expansion

Energy Technology Data Exchange (ETDEWEB)

Medvid’, A., E-mail: mychko@latnet.lv [Riga Technical University, 3 Paula Valdena Str., LV-1048 Riga (Latvia); Mychko, A.; Dauksta, E. [Riga Technical University, 3 Paula Valdena Str., LV-1048 Riga (Latvia); Kosyak, V. [Sumy State University, 2, Rymskogo-Korsakova St., 40007 Sumy (Ukraine); Grase, L. [Riga Technical University, 3 Paula Valdena Str., LV-1048 Riga (Latvia)

2016-06-30

Highlights: • We found two laser induced threshold intensity for CdZnTe crystal. • The laser beam self-focusing lead to increase of intensity of laser radiation at exit surface. • Laser ablation is a result of Te inclusion hydrodynamic expansion. - Abstract: The present paper deals with the laser ablation in CdZnTe crystal irradiated by pulsed infrared laser. Two values of threshold intensities of the laser ablation were determined, namely of about 8.5 and 6.2 MW/cm{sup 2} for the incident and the rear surfaces, correspondingly. Lower intensity of the laser ablation for the rear surface is explained by thermal self-focusing of the laser beam in the CdZnTe crystal due to heating of Te inclusions with a following hydrodynamic expansion.

High-rate irradiation of 15mm muon drift tubes and development of an ATLAS compatible readout driver for micromegas detectors

CERN Document Server

Zibell, Andre

The upcoming luminosity upgrades of the LHC accelerator at CERN demand several upgrades to the detectors of the ATLAS muon spectrometer, mainly due to the proportionally increasing rate of uncorrelated background irradiation. This concerns also the "Small Wheel" tracking stations of the ATLAS muon spectrometer, where precise muon track reconstruction will no longer be assured when around 2020 the LHC luminosity is expected to reach values 2 to 5 times the design luminosity of $1 \\times 10^{34} \\text{cm}^{-2}\\text{s}^{-1}$, and when background hit rates will exceed 10 kHz/cm$^2$. This, together with the need of an additional triggering station in this area with an angular resolution of 1 mrad, requires the construction of "New Small Wheel" detectors for a complete replacement during the long maintenance period in 2018 and 2019. As possible technology for these New Small Wheels, high-rate capable sMDT drift tubes have been investigated, based on the ATLAS 30 mm Monitored Drift Tube technology, but with a smalle...

Development and test of a high-resolution detector for synchrotron radiation imaging; Entwicklung und Test eines hochaufloesenden Detektors zur Bildgebung mit Synchrotronstrahlung

Energy Technology Data Exchange (ETDEWEB)

Ruebsamen, Oliver

2011-07-01

For medical imaging with x-rays, especially coronary angiography in vivo, high position resolution detectors are needed, thereby being able to deliver a contrast better than 1% and a readout speed faster than milliseconds. Since coronary angiography uses a contrast agent like iodine or gadolinium, high energy photons up to 51 keV are needed for imaging. The k-edge subtraction method allows visualizing small vessels because of the sharp jump of absorption at the k-edge of the contrast agent and the almost constant absorption of the surrounding tissue and bone, as well as the measurement of the concentration of the contrast agent to explore heart dynamics. Various detectors and detector materials are in use or development to match these conditions. Solid state Si-, Ge-, CdZnTe-, CdMnTe- or CdTe-seminconductor detectors are used or tested for imaging, each of them having different physical and/or technical problems which prevent to meet the required specifications. These problems are low absorption efficiency (Si) and reduced position resolution if scintillators are used, cooling and poor resolution (Ge) and charge spread along many pixels and technical problems to manufacture a detector chip (CdZnTe, CdMnTe, CdTe). The approach made in this work is a gas filled ionization chamber, built as a integrating line detector. In general, ionization chambers always suffer from poor absorption efficiency, but this can be overcome using the noble Gases Ar, Kr or Xe at very high gas pressures around 50 bar and relatively long (in the range of cm) anode strips. This design is critical for parallax effects, so an x-ray beam with a very small beam divergence is needed. This requirement in combination with the desired contrast and timing resolution can only be achieved by synchrotron light sources of the third generation, like the DORIS ring at DESY, Hamburg or the ESR in Grenoble. A different problem of ionization chambers is fluorescence photons, which produce a background signal

Compton scattering artifacts in electron excited X-ray spectra measured with a silicon drift detector.

Science.gov (United States)

Ritchie, Nicholas W M; Newbury, Dale E; Lindstrom, Abigail P

2011-12-01

Artifacts are the nemesis of trace element analysis in electron-excited energy dispersive X-ray spectrometry. Peaks that result from nonideal behavior in the detector or sample can fool even an experienced microanalyst into believing that they have trace amounts of an element that is not present. Many artifacts, such as the Si escape peak, absorption edges, and coincidence peaks, can be traced to the detector. Others, such as secondary fluorescence peaks and scatter peaks, can be traced to the sample. We have identified a new sample-dependent artifact that we attribute to Compton scattering of energetic X-rays generated in a small feature and subsequently scattered from a low atomic number matrix. It seems likely that this artifact has not previously been reported because it only occurs under specific conditions and represents a relatively small signal. However, with the advent of silicon drift detectors and their utility for trace element analysis, we anticipate that more people will observe it and possibly misidentify it. Though small, the artifact is not inconsequential. Under some conditions, it is possible to mistakenly identify the Compton scatter artifact as approximately 1% of an element that is not present.

Studies of Read-Out Electronics and Trigger for Muon Drift Tube Detectors at High Luminosities

CERN Document Server

Nowak, Sebastian

The Large Hadron Collider (LHC) at the European Centre for Particle Physics, CERN, collides protons with an unprecedentedly high centre-of-mass energy and luminosity. The collision products are recorded and analysed by four big experiments, one of which is the ATLAS detector. For precise measurements of the properties of the Higgs-Boson and searches for new phenomena beyond the Standard Model, the LHC luminosity of $L=10^{34}cm^{-2}s^{-1}$ is planned to be increased by a factor of ten leading to the High Luminosity LHC (HL-LHC). In order to cope with the higher background and data rates, the LHC experiments need to be upgraded. In this thesis, studies for the upgrade of the ATLAS Muon Spectrometer are presented with respect to the read-out electronics of the Monitored Drift Tube (MDT) and the small-diameter Muon Drift Tube (sMDT) chambers and the Level-1 muon trigger. Due to the reduced tube diameter of sMDT chambers, background occupancy and space charge effects are suppressed by an order of magnitude compar...

Detector trends

International Nuclear Information System (INIS)

Charpak, G.

1986-01-01

The author describes briefly the development of detectors for high energy physics experiments. Especially considered are semiconductor microstrip detectors, drift tubes, holographic bubble chambers, scintillating fiber optics, and calorimeters. (HSI).

MPS II drift chamber system

International Nuclear Information System (INIS)

Platner, E.D.

1982-01-01

The MPS II detectors are narrow drift space chambers designed for high position resolution in a magnetic field and in a very high particle flux environment. Central to this implementation was the development of 3 multi-channel custom IC's and one multi-channel hybrid. The system is deadtimeless and requires no corrections on an anode-to-anode basis. Operational experience and relevance to ISABELLE detectors is discussed

Charge loss between contacts of CdZnTe pixel detectors

International Nuclear Information System (INIS)

Bolotnikov, A.E.; Cook, W.R.; Harrison, F.A.; Wong, A.-S.; Schindler, S.M.; Eichelberger, A.C.

1999-01-01

The surface of Cd 1-x Zn x Te (CZT) material has high resistivity but is not a perfect dielectric. Even a small surface conductivity can affect the electric field distribution, and therefore, the charge collection efficiency of a CZT pixel detector. The paper describes studies of this phenomenon for several contact configurations made on a single CZT detector. We have determined the maximum inter-contact separation at which the surface inter-pixel charge loss can be neglected. (author)

Optimized readout configuration for PIXE spectrometers based on Silicon Drift Detectors: Architecture and performance

International Nuclear Information System (INIS)

Alberti, R.; Grassi, N.; Guazzoni, C.; Klatka, T.

2009-01-01

An optimized readout configuration based on a charge preamplifier with pulsed-reset has been designed for Silicon Drift Detectors (SDDs) to be used in Particle Induced X-ray Emission (PIXE) measurements. The customized readout electronics is able to manage the large pulses originated by the protons backscattered from the target material that would otherwise cause significant degradation of X-ray spectra and marked increase in dead time. In this way, the excellent performance of SDDs can be exploited in high-quality proton-induced spectroscopy of low- and medium-energy X-rays. This paper describes the designed readout architecture and the performance characterization carried out in a PIXE setup with MeV proton beams.

Charge loss between contacts of CdZnTe pixel detectors

CERN Document Server

Bolotnikov, A E; Harrison, F A; Wong, A S; Schindler, S M; Eichelberger, A C

1999-01-01

The surface of Cd sub 1 sub - sub x Zn sub x Te (CZT) material has high resistivity but is not a perfect dielectric. Even a small surface conductivity can affect the electric field distribution, and therefore, the charge collection efficiency of a CZT pixel detector. The paper describes studies of this phenomenon for several contact configurations made on a single CZT detector. We have determined the maximum inter-contact separation at which the surface inter-pixel charge loss can be neglected. (author)

Timing calibration of the trigger system for the drift tube detector of the OPERA neutrino oscillation experiment

International Nuclear Information System (INIS)

Lenkeit, Jan

2015-11-01

The OPERA experiment searches for ν μ → ν τ oscillations in an almost pure ν μ beam. The goal is to observe the oscillations in appearance mode by using a large-scale lead/emulsion target to resolve individual ν τ interactions. Magnetic spectrometers measure the charge and momentum of beam induced muons leaving the target sections. The Precision Tracker, a drift tube detector consisting of almost 10000 drift tubes, provides the tracking information inside the spectrometers. The coordinate measurement in the drift tubes is derived from a time measurement relative to an external trigger signal. In order to reach the required momentum resolution of less than 25 % for particle momenta up to 25 GeV, the uncertainty on the trigger timing must not exceed a value of 5 ns. In this thesis, a procedure for the timing calibration of the trigger system is presented. A step-by-step calibration of the corresponding signal paths is described. Applying all calibration results, a spatial resolution of 255 μm is achieved for the Precision Tracker, meeting the specified requirements. Furthermore, a method using the calibrated trigger system for performing time of flight measurements with atmospheric muons is developed. The average error on the measured flight times is ±4.5 ns.

The central drift chamber of the SAPHIR detector - implementation into the experiment and study of its properties

International Nuclear Information System (INIS)

Haas, K.M.

1992-01-01

At the Bonn accelerator facility ELSA the large solid angle detector SAPHIR was built for the investigation of photon induced reactions. A main component of SAPHIR is the central drift chamber (CDC) matching the magneto gap of 1m 3 . The diameter of the in total 1828 hexagonal drift cells is about 18 mm. The subject of this paper is the implementation of the CDC in the experiment. After the description of the hardware follows the presentation of the software tools for filtering and monitoring the data, which have been developed and tested. An algorithm for extracting the space time relationship is presented. The properties of the chamber with an improved gas mixture (Helium/Neon/Isobutane8 21.25:63.75:15) have been investigated. A spatial resolution of about 200 μm was achieved. The efficiency of the chamber is 97% at a tagged photon of 5x10 4 per second crossing the chamber. (orig.) [de

High-rate irradiation of 15 mm muon drift tubes and development of an ATLAS compatible readout driver for micromegas detectors

Energy Technology Data Exchange (ETDEWEB)

Zibell, Andre

2014-06-06

The upcoming luminosity upgrades of the LHC accelerator at CERN demand several upgrades to the detectors of the ATLAS muon spectrometer, mainly due to the proportionally increasing rate of uncorrelated background irradiation. This concerns also the ''Small Wheel'' tracking stations of the ATLAS muon spectrometer, where precise muon track reconstruction will no longer be assured when around 2020 the LHC luminosity is expected to reach values 2 to 5 times the design luminosity of 1 x 10{sup 34} cm{sup -2}s{sup -1}, and when background hit rates will exceed 10 kHz/cm{sup 2}. This, together with the need of an additional triggering station in this area with an angular resolution of 1 mrad, requires the construction of ''New Small Wheel'' detectors for a complete replacement during the long maintenance period in 2018 and 2019. As possible technology for these New Small Wheels, high-rate capable sMDT drift tubes have been investigated, based on the ATLAS 30 mm Monitored Drift Tube technology, but with a smaller diameter of 15 mm. In this work, a prototype sMDT chamber has been tested under the influence of high-rate irradiation with protons, neutrons and photons at the Munich tandem accelerator, simulating the conditions within a high luminosity LHC experiment. Tracking resolution and detection efficiency for minimum ionizing muons are presented as a function of irradiation rate. The experimental muon trigger geometry allows to distinguish between efficiency degradation due to deadtime effects and space charge in the detectors. Using modified readout electronics the analog pulse shape of the detector has been investigated for gain reduction and potential irregularities due to the high irradiation rates and ionization doses. This study shows that the sMDT detectors would fulfill all requirements for successful use in the ATLAS New Small Wheel endcap detector array, with an average spatial resolution of 140 μm and a track

High-rate irradiation of 15 mm muon drift tubes and development of an ATLAS compatible readout driver for micromegas detectors

International Nuclear Information System (INIS)

Zibell, Andre

2014-01-01

The upcoming luminosity upgrades of the LHC accelerator at CERN demand several upgrades to the detectors of the ATLAS muon spectrometer, mainly due to the proportionally increasing rate of uncorrelated background irradiation. This concerns also the ''Small Wheel'' tracking stations of the ATLAS muon spectrometer, where precise muon track reconstruction will no longer be assured when around 2020 the LHC luminosity is expected to reach values 2 to 5 times the design luminosity of 1 x 10 34 cm -2 s -1 , and when background hit rates will exceed 10 kHz/cm 2 . This, together with the need of an additional triggering station in this area with an angular resolution of 1 mrad, requires the construction of ''New Small Wheel'' detectors for a complete replacement during the long maintenance period in 2018 and 2019. As possible technology for these New Small Wheels, high-rate capable sMDT drift tubes have been investigated, based on the ATLAS 30 mm Monitored Drift Tube technology, but with a smaller diameter of 15 mm. In this work, a prototype sMDT chamber has been tested under the influence of high-rate irradiation with protons, neutrons and photons at the Munich tandem accelerator, simulating the conditions within a high luminosity LHC experiment. Tracking resolution and detection efficiency for minimum ionizing muons are presented as a function of irradiation rate. The experimental muon trigger geometry allows to distinguish between efficiency degradation due to deadtime effects and space charge in the detectors. Using modified readout electronics the analog pulse shape of the detector has been investigated for gain reduction and potential irregularities due to the high irradiation rates and ionization doses. This study shows that the sMDT detectors would fulfill all requirements for successful use in the ATLAS New Small Wheel endcap detector array, with an average spatial resolution of 140 μm and a track reconstruction efficiency

Test of a high resolution drift chamber prototype

International Nuclear Information System (INIS)

Comminchau, V.; Deutschmann, M.; Draheim, K.J.; Fritze, P.; Hangarter, K.; Hawelka, P.; Herten, U.; Tonutti, M.; Anderhub, H.; Fehlmann, J.; Hofer, H.; Klein, M.; Paradiso, J.A.; Schreiber, J.; Viertel, G.

1984-06-01

The performance of a drift chamber prototype for a colliding beam vertex detector in a test beam at DESY is described. At one (two) atmosphere gas pressure a spatial resolution of 40 μm (30 μm) per wire for one cm drift length was achieved with a 100 MHz Flash-ADC system. An excellent double track resolution of better than 300 μm over the full drift length of 5 cm can be estimated. (orig.)

Lithium-drifted silicon for harsh radiation environments

Science.gov (United States)

Grant, J.; Buttar, C.; Brozel, M.; Keffous, A.; Cheriet, A.; Bourenane, K.; Bourenane, A.; Kezzoula, F.; Menari, H.

2008-06-01

A model describing the passivation by Li atoms of acceptors arising from radiation damage in Si detectors has been developed. Our studies indicate that it is possible to produce a protocol that will allow the in-situ recovery of lithium-drifted Si particle detectors under irradiation by high-energy particles. Our model for particle damage recovery is supported by preliminary results on the recovery of old, degraded detectors.

Lithium-drifted silicon for harsh radiation environments

Energy Technology Data Exchange (ETDEWEB)

Grant, J. [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)], E-mail: j.grant@physics.gla.ac.uk; Buttar, C. [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Brozel, M. [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); School of Chemistry, University of Bristol, Bristol BS81TS (United Kingdom); Keffous, A.; Cheriet, A.; Bourenane, K.; Bourenane, A.; Kezzoula, F.; Menari, H. [Unite de Developpment de la Technologie du Silicium, 02 Bd Frantz Fanon, B.P. 399 Alger-Gare (Algeria)

2008-06-11

A model describing the passivation by Li atoms of acceptors arising from radiation damage in Si detectors has been developed. Our studies indicate that it is possible to produce a protocol that will allow the in-situ recovery of lithium-drifted Si particle detectors under irradiation by high-energy particles. Our model for particle damage recovery is supported by preliminary results on the recovery of old, degraded detectors.

Alignment of the drift tube detector at the neutrino oscillation experiment OPERA; Alignment des Driftroehrendetektors am Neutrino-Oszillationsexperiment OPERA

Energy Technology Data Exchange (ETDEWEB)

Goellnitz, Christoph

2012-09-15

The present thesis was composed during the course of the OPERA experiment, which aims to give a direct evidence for neutrino oscillations in the channel {nu}{sub {mu}} {yields} {nu}{sub {tau}}. The OPERA detector is designed to observe the appearance of tau neutrinos in an originally pure muon neutrino beam, the CNGS beam. As important part of the detector the precision tracker (PT), a drift tube detector, consists of 9504 drift tubes in 198 modules. In this thesis, several parts of the slow control of the PT are developed and implemented to ensure operation during data taking over several years. The main part is the geometric calibration, the alignment of the detector. The alignment procedure contains both hardware and software parts, the software methods are developed and applied. Using straight particle tracks, the detector components are geometrically corrected. A special challenge for the alignment for the PT is the fact that at this kind of low-rate experiment only a small number of particle tracks is available. With software-based corrections of the module rotation, a systematic error of 0.2 mrad has been attained, for corrections of translation, a systematic error of 32 {mu}m is reached. For the alignment between two adjacent PT walls, the statistical error is less than 8 {mu}m. All results of the position monitoring system are considered. All developed methods are tested with Monte Carlo simulations. The detector requirements ({Delta}p/p {<=} 0.25 below 25 GeV) are met. The analysis of the momentum measurement for high energies above 25 GeV demonstrates the resulting improvement. The mean momentum is falling significantly using the new alignment values. The significance of the detector alignment becomes most evident in the analysis of cosmic particles. The muon charge ratio R{sub {mu}} is expected not to be angular dependent. The {chi}{sup 2} probability of the measured distribution improves up to 58%. The muon charge ratio was also investigated in

Use of silicon drift detectors for the detection of medium-light elements in PIXE

International Nuclear Information System (INIS)

Alberti, R.; Bjeoumikhov, A.; Grassi, N.; Guazzoni, C.; Klatka, T.; Longoni, A.; Quattrone, A.

2008-01-01

In order to fully exploit in PIXE the superior performance of silicon drift detectors especially for the detection of low- and medium-energy X-rays, avoiding in particular the negative effects of backscattered particles, we developed a custom spectrometer based on a 10 mm 2 chip with a thermoelectric Peltier cooler and home-designed front-end electronics, coupled to a weakly focusing polycapillary lens. This paper briefly describes the detector + lens assembly and reports the results of first tests carried out at an external beam line of the LABEC laboratory in Florence. Excellent energy resolution is achieved under real operating conditions in a PIXE run (measured FWHM at 1 keV is 81 eV with a count-rate of 480 cps) and also the lineshapes are very good (FW1/10M over FWHM ratio is 2.1). As a whole, our preliminary tests gave encouraging results and also helped to point out some aspects which it is worthwhile to investigate further (e.g. how X-ray peak intensity ratios may be affected by inaccurate lens alignment), in order to profit fully from such a good performance of the spectrometer

Clean industrial room for drift tube assembling

International Nuclear Information System (INIS)

Glonti, G.L.; Gongadze, A.L.; Evtukhovich, P.G.

2001-01-01

Description of a clean industrial room for assembly of drift tubes for the muon spectrometer of the ATLAS experiment is presented. High quality specifications on the detectors to be produced demanded creation of a workplace with stable temperature and humidity, as well as minimum quantity of dust in the room. Checking of parameters of intra-room air during long period of continuous work has confirmed correctness of the designed characteristics of the climatic system installed in the clean room. The room large volume (∼ 190 m 3 ), the powerful and flexible climatic system, and simplicity of service allow assembling of detectors with length up to 5 m. Subsequent checking of functionality of the assembled detectors has shown high quality of assembling (the amount of rejected tubes does not exceed 2%). It demonstrates conformity to the assembling quality requirements for mass production of drift chambers for the muon spectrometer. (author)

Clean Industrial Room for Drift Tube Assembling

CERN Document Server

Glonti, GL; Evtoukhovitch, P G; Kroa, G; Manz, A; Potrap, I N; Rihter, P; Stoletov, G D; Tskhadadze, E G; Chepurnov, V F; Chirkov, A V; Shelkov, G A

2001-01-01

Description of a clean industrial room for assembly of drift tubes for the muon spectrometer of the ATLAS experiment is presented. High quality specifications on the detectors to be produced demanded creation of a workplace with stable temperature and humidity, as well as minimum quantity of dust in the room. Checking of parameters of intra-room air during long period of continuous work has been confirmed correctness of the designed characteristics of the climatic system installed in the clean room. The room large volum (\\sim 190 m^3), the powerful and flexible climatic system, and simplicity of service allow assembling of detectors with length up to 5 m. Subsequent checking of functionality of the assembled detectors has shown high quality of assembling (the amount of rejected tubes does not exceed 2 %). It demonstrates conformity to the assembling quality requirements for mass production of drift chambers for the muon spectrometer.

Precise muon drift tube detectors for high background rate conditions

Energy Technology Data Exchange (ETDEWEB)

Engl, Albert

2011-08-04

The muon spectrometer of the ATLAS-experiment at the Large Hadron Collider consists of drift tube chambers, which provide the precise measurement of trajectories of traversing muons. In order to determine the momentum of the muons with high precision, the measurement of the position of the muon in a single tube has to be more accurate than {sigma}{<=}100 {mu}m. The large cross section of proton-proton-collisions and the high luminosity of the accelerator cause relevant background of neutrons and {gamma}s in the muon spectrometer. During the next decade a luminosity upgrade to 5.10{sup 34} cm{sup -2}s{sup -1} is planned, which will increase the background counting rates considerably. In this context this work deals with the further development of the existing drift chamber technology to provide the required accuracy of the position measurement under high background conditions. Two approaches of improving the drift tube chambers are described: - In regions of moderate background rates a faster and more linear drift gas can provide precise position measurement without changing the existing hardware. - At very high background rates drift tube chambers consisting of tubes with a diameter of 15 mm are a valuable candidate to substitute the CSC muon chambers. The single tube resolution of the gas mixture Ar:CO{sub 2}:N{sub 2} in the ratio of 96:3:1 Vol %, which is more linear and faster as the currently used drift gas Ar:CO{sub 2} in the ratio of 97:3 Vol %, was determined at the Cosmic Ray Measurement Facility at Garching and at high {gamma}-background counting rates at the Gamma Irradiation Facility at CERN. The alternative gas mixture shows similar resolution without background. At high background counting rates it shows better resolution as the standard gas. To analyse the data the various parts of the setup have to be aligned precisely to each other. The change to an alternative gas mixture allows the use of the existing hardware. The second approach are drift tubes

Post-growth annealing of Bridgman-grown CdZnTe and CdMnTe crystals for room-temperature nuclear radiation detectors

International Nuclear Information System (INIS)

Egarievwe, Stephen U.; Yang, Ge; Egarievwe, Alexander A.; Okwechime, Ifechukwude O.; Gray, Justin; Hales, Zaveon M.; Hossain, Anwar; Camarda, Giuseppe S.; Bolotnikov, Aleksey E.; James, Ralph B.

2015-01-01

Bridgman-grown cadmium zinc telluride (CdZnTe or CZT) and cadmium manganese telluride (CdMnTe or CMT) crystals often have Te inclusions that limit their performances as X-ray- and gamma-ray-detectors. We present here the results of post-growth thermal annealing aimed at reducing and eliminating Te inclusions in them. In a 2D analysis, we observed that the sizes of the Te inclusions declined to 92% during a 60-h annealing of CZT at 510 °C under Cd vapor. Further, tellurium inclusions were eliminated completely in CMT samples annealed at 570 °C in Cd vapor for 26 h, whilst their electrical resistivity fell by an order of 10 2 . During the temperature-gradient annealing of CMT at 730 °C and an 18 °C/cm temperature gradient for 18 h in a vacuum of 10 −5 mbar, we observed the diffusion of Te from the sample, so causing a reduction in size of the Te inclusions. For CZT samples annealed at 700 °C in a 10 °C/cm temperature gradient, we observed the migration of Te inclusions from a low-temperature region to a high one at 0.022 μm/s. During the temperature-gradient annealing of CZT in a vacuum of 10 −5 mbar at 570 °C and 30 °C/cm for 18 h, some Te inclusions moved toward the high-temperature side of the wafer, while other inclusions of the same size, i.e., 10 µm in diameter, remained in the same position. These results show that the migration, diffusion, and reaction of Te with Cd in the matrix of CZT- and CMT-wafers are complex phenomena that depend on the conditions in local regions, such as composition and structure, as well as on the annealing conditions

High Flux Energy-Resolved Photon-Counting X-Ray Imaging Arrays with CdTe and CdZnTe for Clinical CT

International Nuclear Information System (INIS)

Barber, William C.; Hartsough, Neal E.; Gandhi, Thulasidharan; Iwanczyk, Jan S.; Wessel, Jan C.; Nygard, Einar; Malakhov, Nail; Wawrzyniak, Gregor; Dorholt, Ole; Danielsen, Roar

2013-06-01

We have fabricated fast room-temperature energy dispersive photon counting x-ray imaging arrays using pixellated cadmium zinc (CdTe) and cadmium zinc telluride (CdZnTe) semiconductors. We have also fabricated fast application specific integrated circuits (ASICs) with a two dimensional (2D) array of inputs for readout from the CdZnTe sensors. The new CdTe and CdZnTe sensors have a 2D array of pixels with a 0.5 mm pitch and can be tiled in 2D. The new 2D ASICs have four energy discriminators per pixel with a linear energy response across the entire dynamic range for clinical CT. The ASICs can also be tiled in 2D and are designed to fit within the active area of the 2D sensors. We have measured several important performance parameters including; an output count rate (OCR) in excess of 20 million counts per second per square mm, an energy resolution of 7 keV full width at half maximum (FWHM) across the entire dynamic range, and a noise floor less than 20 keV. This is achieved by directly interconnecting the ASIC inputs to the pixels of the CdTE and CdZnTe sensors incurring very little additional capacitance. We present a comparison of the performance of the CdTe and CdZnTe sensors including the OCR, FWHM energy resolution, and noise floor. (authors)

Recent state of CdTe-based radiation detectors

International Nuclear Information System (INIS)

Ohno, R.

2004-01-01

Recent state for development of CdTe-based radiation detectors is reviewed. The progress of the technologies such as the crystal growth of CdTe and CdZnTe, the deposition of electrodes on the crystal, the design of read out ASIC, and the bonding between crystal and ASIC, opened the way for the development of imaging devices for practical uses. A X-ray imager for non destructive inspections and a gamma ray imager for small animal radioisotope experiments or nuclear medicine are presented as examples. (author)

Argus drift chamber

Energy Technology Data Exchange (ETDEWEB)

Danilov, M; Nagovizin, V; Hasemann, H; Michel, E; Schmidt-Parzefall, W; Wurth, R; Kim, P

1983-11-15

The ARGUS detector came into operation at the DORIS-II e/sup +/s/sup -/ storage ring at the end of 1982. Its two meter long drift chamber contains 5940 sense and 24588 field wires organized in uniform 18x18.8 mm/sup 2/ drift cells filling the whole volume. These cells form 36 layers, 18 of which provide stereo views. Each sense wire is equipped with a single hit TDC and ADC for coordinate and dE/dx measurements. The chamber is operated with propane to improve momentum and dE/dx resolution. The drift chamber design and initial performance are presented. With a very crude space-time relation approximation and without all the necessary corrections applied a spatial resolution of about 200 ..mu..m was obtained for half of the drift cell volume. Further corrections should improve this result. An intrinsic dE/dx resolution of 4.2% and an actual resolution of 5% were obtained for cosmic muons and also for Bhabha scattered electrons. An actual dE/dx resolution of 5.6% was obtained for pions from e/sup +/e/sup -/ annihilation data with almost no track selection. A relativistic rise of 30% was observed in good agreement with theory. The long-term stability is still to be investigated.

X-Ray and Gamma-Ray Radiation Detector

DEFF Research Database (Denmark)

2015-01-01

Disclosed is a semiconductor radiation detector for detecting X-ray and / or gamma-ray radiation. The detector comprises a converter element for converting incident X-ray and gamma-ray photons into electron-hole pairs, at least one cathode, a plurality of detector electrodes arranged with a pitch...... (P) along a first axis, a plurality of drift electrodes, a readout circuitry being configured to read out signals from the plurality of detector electrodes and a processing unit connected to the readout circuitry and being configured to detect an event in the converter element. The readout circuitry...... is further configured to read out signals from the plurality of drift electrodes, and the processing unit is further configured to estimate a location of the event along the first axis by processing signals obtained from both the detector electrodes and the drift electrodes, the location of the event along...

1-D position sensitive single carrier semiconductor detectors

International Nuclear Information System (INIS)

Zhong He; Knoll, G.F.; Wehe, D.K.; Rojeski, R.; Mastrangelo, C.H.; Hammig, M.; Barrett, C.; Uritani, A.

1996-01-01

A single polarity charge sensing method has been studied using coplanar electrodes on 5 mm cubes of CdZnTe γ-ray detectors. This method can ameliorate the hole trapping problem of room-temperature semiconductor detectors. Our experimental results confirm that the energy resolution is dramatically improved compared with that obtained using the conventional readout method, but is still about an order of magnitude worse than the theoretical limit. A method to obtain the γ-ray interaction depth between the cathode and the anode is presented here. This technique could be used to correct for the electron trapping as a function of distance from the coplanar electrodes. Experimental results showed that a position resolution of about 0.9 mm FWHM at 122 keV can be obtained. These results will be of interest in the design of higher performance room-temperature semiconductor γ-ray detectors. (orig.)

Report of the general purpose detector group

International Nuclear Information System (INIS)

Barbaro-Galtieri, A.; Bartel, W.; Bulos, F.; Cool, R.; Hanson, G.; Koetz, U.; Kottahaus, R.; Loken, S.; Luke, D.; Rothenberg, A.

1975-01-01

A general purpose detector for PEP is described. The main components of this detector are a l meter radius, 15 kilogauss superconducting solenoidal magnet with drift chambers to detect and measure the momentum of charged particles, a liquid argon neutral detector and hadron calorimeter, and a system of Cherenkov and time-of-flight counters for identification of charged hadrons. A major consideration in the design of this detector was that it be flexible: the magnet coil and drift chambers form a core around which various apparatus for specialized detection can be placed

The drift chamber array at the external target facility in HIRFL-CSR

Science.gov (United States)

Sun, Y. Z.; Sun, Z. Y.; Wang, S. T.; Duan, L. M.; Sun, Y.; Yan, D.; Tang, S. W.; Yang, H. R.; Lu, C. G.; Ma, P.; Yu, Y. H.; Zhang, X. H.; Yue, K.; Fang, F.; Su, H.

2018-06-01

A drift chamber array at the External Target Facility in HIRFL-CSR has been constructed for three-dimensional particle tracking in high-energy radioactive ion beam experiments. The design, readout, track reconstruction program and calibration procedures for the detector are described. The drift chamber array was tested in a 311 AMeV 40Ar beam experiment. The detector performance based on the measurements of the beam test is presented. A spatial resolution of 230 μm is achieved.

Position reconstruction in drift chambers operated with Xe, $CO_{2}$ (15\\%)

CERN Document Server

Adler, C; Appelshäuser, H; Bielcikova, J; Blume, C; Braun-Munzinger, P; Bucher, D; Busch, O; Catanescu, V; Ciobanu, M; Daues, H W; Emschermann, D; Fateev, O V; Foka, P; Garabatos, C; Gunji, T; Herrmann, N; Inuzuka, M; Ivanov, M; Kislov, E; Lindenstruth, V; Lippmann, C; Ludolphs, W; Mahmoud, T; Petracek, V; Petrovici, M; Radomski, S; Rusanov, I; Sandoval, A; Santo, R; Schicker, R; Schwarz, K; Simon, R S; Smykov, L P; Soltveit, H K; Stachel, J; Stelzer, H; Tsiledakis, G; Vulpescu, B; Wessels, J P; Windelband, B; Yurevich, V; Zanevsky, Yu; Zaudtke, O

2005-01-01

We present measurements of position and angular resolution of drift chambers operated with a Xe, CO2 (15%) mixture. The results are compared to Monte Carlo simulations and important systematic effects - in particular the dispersive nature of the absorption of transition radiation and non-linearities - are discussed. The measurements were carried out with prototype drift chambers of the ALICE Transition Radiation Detector, but our findings can be generalized to other drift chambers with similar geometry, where the electron drift is perpendicular to the wire planes.

Single wire drift chamber design

International Nuclear Information System (INIS)

Krider, J.

1987-01-01

This report summarizes the design and prototype tests of single wire drift chambers to be used in Fermilab test beam lines. The goal is to build simple, reliable detectors which require a minimum of electronics. Spatial resolution should match the 300 μm rms resolution of the 1 mm proportional chambers that they will replace. The detectors will be used in beams with particle rates up to 20 KHz. Single track efficiency should be at least 99%. The first application will be in the MT beamline, which has been designed for calibration of CDF detectors. A set of four x-y modules will be used to track and measure the momentum of beam particles

Measurements of the drift velocity using a small gas chamber for monitoring of the CMS muon system

CERN Document Server

Frangenheim, J

This diploma thesis presents measurements of the drift velocity of electrons in gas. A small gas detector (VDC1 ) is used. This chamber is intended for measurement and monitoring of the drift velocity in the gas of the muon chambers of the gas detector system in the barrel area of the CMS-detector2 at the European Research Center for Particle Physics CERN near Geneva. The drift velocity is, together with the drift time, a key parameter for measurements with drift chambers. The aim of this thesis is to perform test measurements to determine parameters of the chamber and also to estimate systematic errors. Beside the drift velocity, further parameters of the gas like the pressure and the temperature are measured and accounted for. For the further work with the VDCs, analysis software has been created which is used for the analysis of the measurements. Parallel to this work, necessary improvements, e.g. for the high voltage robustness, were also implemented and tested. In addition, studies and test measurements ...

CdCl2 passivation of polycrystalline CdMgTe and CdZnTe absorbers for tandem photovoltaic cells

Science.gov (United States)

Swanson, Drew E.; Reich, Carey; Abbas, Ali; Shimpi, Tushar; Liu, Hanxiao; Ponce, Fernando A.; Walls, John M.; Zhang, Yong-Hang; Metzger, Wyatt K.; Sampath, W. S.; Holman, Zachary C.

2018-05-01

As single-junction silicon solar cells approach their theoretical limits, tandems provide the primary path to higher efficiencies. CdTe alloys can be tuned with magnesium (CdMgTe) or zinc (CdZnTe) for ideal tandem pairing with silicon. A II-VI/Si tandem holds the greatest promise for inexpensive, high-efficiency top cells that can be quickly deployed in the market using existing polycrystalline CdTe manufacturing lines combined with mature silicon production lines. Currently, all high efficiency polycrystalline CdTe cells require a chloride-based passivation process to passivate grain boundaries and bulk defects. This research examines the rich chemistry and physics that has historically limited performance when extending Cl treatments to polycrystalline 1.7-eV CdMgTe and CdZnTe absorbers. A combination of transmittance, quantum efficiency, photoluminescence, transmission electron microscopy, and energy-dispersive X-ray spectroscopy clearly reveals that during passivation, Mg segregates and out-diffuses, initially at the grain boundaries but eventually throughout the bulk. CdZnTe exhibits similar Zn segregation behavior; however, the onset and progression is localized to the back of the device. After passivation, CdMgTe and CdZnTe can render a layer that is reduced to predominantly CdTe electro-optical behavior. Contact instabilities caused by inter-diffusion between the layers create additional complications. The results outline critical issues and paths for these materials to be successfully implemented in Si-based tandems and other applications.

Analysis of Study Trend of Growth and Characterization of CdZnTe Single Crystal

International Nuclear Information System (INIS)

Lee, Kyu Hong; Ha, Jang Ho; Kim, Han Soo

2011-05-01

CdZnTe (CZT) alloys are very important semiconducting compounds due to their use in several strategic applications in medical, space, and security devices, especially, radiation detector. Specific problems of the bulk crystal growth are still to be solved. However, since industries require excellent bulk CZT crystals, a strong effort is being organized worldwide to optimize the growth process and obtain better material. This report presents the study trend of the bulk CZT crystal growth and characteristics. After the first section where the problems connected to the complicated phase diagram of CZT are presented, the second section describes the various general physical and chemical properties, together with the compensation problems of the CZT material. In the third section, various growth methods are described, paying attention to the defects generated in the different cases. Further, the annealing process which is an essential step for improving the crystal quality is described. In the last section, the general material characterization methods are presented, as a scientific approach for assessing the quality of the bulk crystal

CdTe and CdZnTe detectors in nuclear medicine

CERN Document Server

Scheiber, C

2000-01-01

Nuclear medicine diagnostic applications are growing in search for more disease specific or more physiologically relevant imaging. The data are obtained non-invasively from large field gamma cameras or from miniaturised probes. As far as single photon emitters are concerned, often labelled with sup 9 sup 9 sup m Tc (140 keV, gamma), nuclear instrumentation deals with poor counting statistics due to the method of spatial localisation and low contrast to noise due to scatter in the body. Since the 1960s attempts have been made to replace the NaI scintillator by semiconductor detectors with better spectrometric characteristics to improve contrast and quantitative measurements. They allow direct conversion of energy and thus more compact sensors. Room-temperature semiconductor detectors such as cadmium tellure and cadmium zinc tellure have favourable physical characteristics for medical applications which have been investigated in the 1980s. During one decade, they have been used in miniaturised probes such as fo...

The BABAR Detector

Energy Technology Data Exchange (ETDEWEB)

Luth, Vera G

2001-05-18

BABAR, the detector for the SLAC PEP-II asymmetric e{sup +}e{sup -} B Factory operating at the {Upsilon}(4S) resonance, was designed to allow comprehensive studies of CP-violation in B-meson decays. Charged particle tracks are measured in a multi-layer silicon vertex tracker surrounded by a cylindrical wire drift chamber. Electromagentic showers from electrons and photons are detected in an array of CsI crystals located just inside the solenoidal coil of a superconducting magnet. Muons and neutral hadrons are identified by arrays of resistive plate chambers inserted into gaps in the steel flux return of the magnet. Charged hadrons are identified by dE/dx measurements in the tracking detectors and in a ring-imaging Cherenkov detector surrounding the drift chamber. The trigger, data acquisition and data-monitoring systems, VME- and network-based, are controlled by custom-designed online software. Details of the layout and performance of the detector components and their associated electronics and software are presented.

Efficiency profile method to study the hit efficiency of drift chambers

International Nuclear Information System (INIS)

Abyzov, A.; Bel'kov, A.; Lanev, A.; Spiridonov, A.; Walter, M.; Hulsbergen, W.

2002-01-01

A method based on the usage of efficiency profile is proposed to estimate the hit efficiency of drift chambers with a large number of channels. The performance of the method under real conditions of the detector operation has been tested analysing the experimental data from the HERA-B drift chambers

Radiation effects on II-VI compound-based detectors

CERN Document Server

Cavallini, A; Dusi, W; Auricchio, N; Chirco, P; Zanarini, M; Siffert, P; Fougeres, P

2002-01-01

The performance of room temperature CdTe and CdZnTe detectors exposed to a radiation source can be strongly altered by the interaction of the ionizing particles and the material. Up to now, few experimental data are available on the response of II-VI compound detectors to different types of radiation sources. We have carried out a thorough investigation on the effects of gamma-rays, neutrons and electron irradiation both on CdTe : Cl and Cd sub 0 sub . sub 9 Zn sub 0 sub . sub 1 Te detectors. We have studied the detector response after radiation exposure by means of dark current measurements and of quantitative spectroscopic analyses at low and medium energies. The deep traps present in the material have been characterized by means of PICTS (photo-induced current transient spectroscopy) analyses, which allow to determine the trap apparent activation energy and capture cross-section. The evolution of the trap parameters with increasing irradiation doses has been monitored for all the different types of radiati...

The OPAL muon barrel detector

International Nuclear Information System (INIS)

Akers, R.J.; Allison, J.; Ashton, P.; Bahan, G.A.; Baines, J.T.M.; Banks, J.N.; Barlow, R.J.; Barnett, S.; Beeston, C.; Chrin, J.T.M.; Clowes, S.G.; Davies, O.W.; Duerdoth, I.P.; Hinde, P.S.; Hughes-Jones, R.E.; Lafferty, G.D.; Loebinger, F.K.; Macbeth, A.A.; McGowan, R.F.; Moss, M.W.; Murphy, P.G.; Nijjhar, B.; O'Dowd, A.J.P.; Pawley, S.J.; Phillips, P.D.; Richards, G.E.; Skillman, A.; Stephens, K.; Tresillian, N.J.; Wood, N.C.; Wyatt, T.R.

1995-01-01

The barrel part of the OPAL muon detector consists of 110 drift chambers forming four layers outside the hadron absorber. Each chamber covers an area of 1.2 m by up to 10.4 m and has two cells with wires parallel to the beam and a drift distance of 297 mm. A detailed description of the design, construction, operation and performance of the sub-detector is given. The system has been operating successfully since the start of LEP in 1989. ((orig.))

System of cylindrical drift chambers in a superconducting solenoid

International Nuclear Information System (INIS)

Camilleri, L.; Blumenfeld, B.J.; Dimcovski, Z.

1978-01-01

A superconducting solenoid at the CERN ISR was equipped with a system of high accuracy cylindrical drift chambers. This detector consists of eight layers of field shaped drift cells with a delay line opposite each sense wire to provide coupled two dimensional readout. The design, construction, and operation of this system are discussed. The resolution and performance of the delay lines and sense wires under ISR running conditions are shown

Stanford's big new detector

International Nuclear Information System (INIS)

Anon.

1984-01-01

A detector constructed for the Standford Linear Collider is described. It consists of a central drift chamber in the field of a surrounding superconducting solenoid. Furthermore included are a Cherenkov ring imaging detector for particle identification and a liquid argon calorimeter. (HSI).

Study on Characteristic of CdZnTe Semiconductor Detectors for Alpha Particle Measurement

International Nuclear Information System (INIS)

Kang, Sang Mook; Ha, Jang Ho; Kim, Yong Kyun; Park, Se Hwan; Kim, Han Soo; Chung, Chong Eun

2005-01-01

The last 2-3 years have seen continued effort in the development of a wide band gap room-temperature compound semiconductor devices aimed principally at photon imaging covering hard X-rays, synchrotrons, and low to medium energy gamma rays. Especially, among the semiconductor materials of a wide band gap, CdZnTe(CZT) has commonly used X-ray and gammaray detection applications because of the opportunity to achieve and excellent spectral and spatial resolution. It has recently been demonstrated that CZT can be used as an ancillary detector with the ability to detect both alpha particles and X-ray at room temperature. CZT detectors are relatively inexpensive compared with some silicon detectors, and are priced about the same as amorphous silicon and photodiodes which are routinely used for charged particle detection. In this paper, we investigated the use of the CZT semiconductor material as an alpha particles detector

Silicon drift detector based X-ray spectroscopy diagnostic system for the study of non-thermal electrons at Aditya tokamak.

Science.gov (United States)

Purohit, S; Joisa, Y S; Raval, J V; Ghosh, J; Tanna, R; Shukla, B K; Bhatt, S B

2014-11-01

Silicon drift detector based X-ray spectrometer diagnostic was developed to study the non-thermal electron for Aditya tokamak plasma. The diagnostic was mounted on a radial mid plane port at the Aditya. The objective of diagnostic includes the estimation of the non-thermal electron temperature for the ohmically heated plasma. Bi-Maxwellian plasma model was adopted for the temperature estimation. Along with that the study of high Z impurity line radiation from the ECR pre-ionization experiments was also aimed. The performance and first experimental results from the new X-ray spectrometer system are presented.

Drift chamber tracking with a VLSI neural network

International Nuclear Information System (INIS)

Lindsey, C.S.; Denby, B.; Haggerty, H.; Johns, K.

1992-10-01

We have tested a commercial analog VLSI neural network chip for finding in real time the intercept and slope of charged particles traversing a drift chamber. Voltages proportional to the drift times were input to the Intel ETANN chip and the outputs were recorded and later compared off line to conventional track fits. We will discuss the chamber and test setup, the chip specifications, and results of recent tests. We'll briefly discuss possible applications in high energy physics detector triggers

A 32-channel, 025 mum CMOS ASIC for the readout of the silicon drift detectors of the ALICE experiment

CERN Document Server

Mazza, G; Anghinolfi, F; Martínez, M I; Rivetti, A; Rotondo, F

2004-01-01

In this paper we present a 32 channel ASIC prototype for the readout of the silicon drift detectors (SDDs) of the ALICE experiment. The ASIC integrates on the same substrate 32 transimpedance amplifiers, a 32 x 256 cell analogue memory and 16 successive approximation 10 bit A/D converters. The circuit amplifies and samples at 40 MS/s the input signal in a continuous way. When an external trigger signal validates the acquisition, the sampling is stopped and the data are digitized at lower speed (0.5 MS/s). The chip has been designed and fabricated in a commercial 0.25 mum CMOS technology. It has been extensively tested both on a bench and connected with a detector in several beam tests. In this paper both design issues and test results are presented. The radiation tolerance of the design has been increased by special layout techniques. Total dose irradiation tests are also presented.

The Drift Chambers Handbook, introductory laboratory course (based on, and adapted from, A H Walenta's course notes)

International Nuclear Information System (INIS)

Ferreira, Ix-B GarcIa; Herrera, J GarcIa; Villasenor, L

2005-01-01

This handbook was written for the Drift Chambers introductory laboratory course to be held at 11th Mexican School of Particles and Fields that will be held at the Universidad Veracruzana on the campus of the University at Xalapa, Veracruz, Mexico. This course intends to introduce drift chambers, which play an important role in particle physics experiments as tracking detectors. We start such laboratory course with a brief review of the physics theoretical background. The experimental setup consists of a single-sided, single-cell drift chamber, a plastic scintillator detector, the standard P-10 gas mixture (90% Ar, 10% CH 4 ) and a collimated 90 Sr source. The measurements on the drift velocity of electrons, its change as a function of a drift field, gas gain and diffusion are performed at this laboratory course

Comparison of silicon drift detectors made by Amptek and PNDetectors in application to the PHA system for W7-X

Directory of Open Access Journals (Sweden)

Krawczyk Natalia

2016-12-01

Full Text Available The paper presents comparison of two silicon drift detectors (SDD, one made by Amptek, USA, and the second one by PNDetector, Germany, which are considered for a soft X-ray diagnostic system for W7-X. The sensitive area of the first one is 7 mm2 × 450 μm and the second one is 10 mm2 × 450 μm. The first detector is cooled by a double-stage Peltier element, while the second detector is cooled by single-stage Peltier element. Each one is equipped with a field-effect transistor (FET. In the detector from Amptek, the FET is mounted separately, while in the detector from PNDetector, the FET is integrated on the chip. The nominal energy resolution given by the producers of the first and the second one is 136 eV@5.9 keV (at -50°C and 132 eV@5.9 keV (at -20°C, respectively. Owing to many advantages, the investigated detectors are good candidates for soft X-ray measurements in magnetic confinement devices. They are suitable for soft X-ray diagnostics, like the pulse height analysis (PHA system for the stellarator Wendelstein 7-X, which has been developed and manufactured at the Institute of Plasma Physics and Laser Microfusion (IPPLM, Warsaw, in collaboration with the Max Planck Institute for Plasma Physics (IPP, Greifswald. The diagnostic is important for the measurements of plasma electron temperature, impurities content, and possible suprathermal tails in the spectra. In order to choose the best type of detector, analysis of technical parameters and laboratory tests were done. Detailed studies show that the most suitable detector for the PHA diagnostics is the PNDetector.

Dimethyl ether as a drift-chamber gas

International Nuclear Information System (INIS)

Bari, G.; Basile, M.; Bonvicini, G.; Cara Romeo, G.; Casaccia, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; D'Ali, G.; Del Papa, C.; Focardi, S.; Iacobucci, G.; Maccarrone, G.; Massam, T.; Motta, F.; Nania, R.; Palmonari, F.; Prisco, G.; Sartorelli, G.; Susinno, G.; Votano, L.; Zichichi, A.; Istituto Nazionale di Fisica Nucleare, Bologna; European Organization for Nuclear Research, Geneva; Istituto Nazionale di Fisica Nucleare, Frascati; Michigan Univ., Ann Arbor; Palermo Univ.

1986-01-01

We have continued the testing of dimethyl ether as a drift-chamber gas in order to improve the understanding of its properties. In particular, we report on measurement accuracy, on systematic effects, and some preliminary data on the ageing of a detector filled with dimethyl ether. (orig.)

Stability of the spectral responsivity of cryogenically cooled InSb infrared detectors

International Nuclear Information System (INIS)

Theocharous, Evangelos

2005-01-01

The spectral responsivity of two cryogenically cooled InSb detectors was observed to drift slowly with time. The origin of these drifts was investigated and was shown to occur due to a water-ice thin film that was deposited onto the active areas of the cold detectors. The presence of the ice film (which is itself a dielectric film) modifies the transmission characteristics of the antireflection coatings deposited on the active areas of the detectors, thus giving rise to the observed drifts. The magnitude of the drifts was drastically reduced by evacuating the detector dewars while baking them at 50 deg. C for approximately 48 h. All InSb detectors have antireflection coatings to reduce the Fresnel reflections and therefore enhance their spectral responsivity. This work demonstrates that InSb infrared detectors should be evacuated and baked at least annually and in some cases (depending on the quality of the dewar and the measurement uncertainty required) more frequently. These observations are particularly relevant to InSb detectors mounted in dewars that use rubber O rings since the ingress of moisture was found to be particularly serious in this type of dewar

Development of Silicon Drift Detectors using Boron layer technology

OpenAIRE

Golshani, N.

2015-01-01

Radiation detectors are used in a large variety of fields such as medicine, security, defense, geophysics, industry and physics. They have been developed to detect the energy or position of radiation or charge particles. In Chapter 1 several X-ray detectors were introduced briefly. In gas filled X-ray detectors, incoming photons ionize inert gas and create electron and ions which can be collected at a thin wire anode inside of the chamber. The advantage of this type of detector is the possibi...

New detector concepts

International Nuclear Information System (INIS)

Kemmer, J.; Lutz, G.

1986-07-01

On the basis of the semiconductor drift chamber many new detectors are proposed, which enable the determination of energy, energy loss, position and penetration depth of radiation. A novel integrated transistor-detector configuration allows non destructive repeated readout and amplification of the signal. The concept may be used for the construction of one or two-dimensional PIXEL arrays. (orig.)

Construction and Test of New Precision Drift-Tube Chambers for the ATLAS Muon Spectrometer

CERN Document Server

INSPIRE-00218480

2017-02-11

ATLAS muon detector upgrades aim for increased acceptance for muon triggering and precision tracking and for improved rate capability of the muon chambers in the high-background regions of the detector with increasing LHC luminosity. The small-diameter Muon Drift Tube (sMDT) chambers have been developed for these purposes. With half of the drift-tube diameter of the MDT chambers and otherwise unchanged operating parameters, sMDT chambers share the advantages of the MDTs, but have an order of magnitude higher rate capability and can be installed in detector regions where MDT chambers do not fit in. The chamber assembly methods have been optimized for mass production, minimizing construction time and personnel. Sense wire positioning accuracies of 5 ?micons have been achieved in serial production for large-size chambers comprising several hundred drift tubes. The construction of new sMDT chambers for installation in the 2016/17 winter shutdown of the LHC and the design of sMDT chambers in combination with new R...

Characterization of spectrometric photon-counting X-ray detectors at different pitches

Science.gov (United States)

Jurdit, M.; Brambilla, A.; Moulin, V.; Ouvrier-Buffet, P.; Radisson, P.; Verger, L.

2017-09-01

There is growing interest in energy-sensitive photon-counting detectors based on high flux X-ray imaging. Their potential applications include medical imaging, non-destructive testing and security. Innovative detectors of this type will need to count individual photons and sort them into selected energy bins, at several million counts per second and per mm2. Cd(Zn)Te detector grade materials with a thickness of 1.5 to 3 mm and pitches from 800 μm down to 200 μm were assembled onto interposer boards. These devices were tested using in-house-developed full-digital fast readout electronics. The 16-channel demonstrators, with 256 energy bins, were experimentally characterized by determining spectral resolution, count rate, and charge sharing, which becomes challenging at low pitch. Charge sharing correction was found to efficiently correct X-ray spectra up to 40 × 106 incident photons.s-1.mm-2.

Diogene pictorial drift chamber

International Nuclear Information System (INIS)

Gosset, J.

1984-01-01

A pictorial drift chamber, called DIOGENE, has been installed at Saturne in order to study central collisions of high energy heavy ions. It has been adapted from the JADE internal detector, with two major differences to be taken into account. First, the center-of-mass of these collisions is not identical to the laboratory reference frame. Second, the energy loss and the momentum ranges of the particles to be detected are different from the ones in JADE. It was also tried to keep the cost as small as possible, hence the choice of minimum size and minimum number of sensitive wires. Moreover the wire planes are shifted from the beam axis: this trick helps very much to quickly reject the bad tracks caused by the ambiguity of measuring drift distances (positive or negative) through times (always positive)

Feasibility tests of a high resolution sampling radial drift chamber

International Nuclear Information System (INIS)

Huth, J.

1985-01-01

The design concept and results of feasibility tests for a vertex detector intended for use in the TPC-PEP4/9 experiment are presented. The detector is based on a slow radial drift in dimethyl ether. High resolution localization of the avalanches at the sense wire is accomplished with nearby pickup wires and the utilization of waveform sampling electronics. The avalanche angular coordinate measurements, combined with knowledge of the electric field distribution and drift velocity permit reconstruction of the trajectory using essentially all track information. Measurements with a test chamber constructed to study characteristics of avalanche localization indicate that the recoverable track information in one centimeter of dimethyl ether at 1.5 atm is equivalent to 30 measurements of 40 μm accuracy. (orig.)

Position-sensitive X-ray detectors

International Nuclear Information System (INIS)

Hendrix, J.

1982-01-01

In this review of the application of different types of position sensitive detectors to synchrotron radiation, discussion of the proportional counters based on the gas amplification principle forms a major part. Other topics reviewed are detector requirements, multiwire proportional chamber system, drift chamber type detectors, TV detectors, and recent developments, such as that based on a micro-channel plate as the amplifying element, and charge-coupled devices. (U.K.)

A 32-channels, 025 mu m CMOS ASIC for the readout of the Silicon Drift Detectors of the ALICE experiment

CERN Document Server

Mazza, G; Anelli, G; Anghinolfi, F; Martínez, M I; Rotondo, F

2004-01-01

In this paper we present a 32 channel ASIC prototype for the readout of the Silicon Drift Detectors (SDDs) of the ALICE experiment. The ASIC integrates on the same chip 32 transimpedance amplifiers, a 32*256 cells analogue memory and 16 successive approximation 10 bit A /D converters. The circuit amplifies and samples at 40 MS/s the input signal in a continuous way; when an external trigger signal validates the acquisition, the sampling is stopped and the data are digitized at lower speed (0.5 MS/s). The chip has been designed and fabricated in a commercial. 0.25 mu m CMOS technology. It has been extensively tested both on a bench and connected with the detector in several beam tests. In this paper both design issues and test results are presented. The commercial technology used for the design has been yield radiation tolerant with special layout techniques. Total dose irradiation tests are also presented. (13 refs).

Component and system tests of the SLD Cerenkov Ring Imaging Detector

International Nuclear Information System (INIS)

Antilogus, P.; Bird, F.; Aston, D.; Dasu, S.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.; Nagamine, T.; Pavel, T.; Muller, D.; Williams, S.; Bienz, T.; Dolinsky, S.; Solodov, E.; Coyle, P.; Cavalli-Sforza, M.; Coyne, D.; Gagnon, P.; Liu, X.; Williams, D.A.

1990-01-01

The components of the SLD barrel Cerenkov Ring Imaging Detector (CRID) are now built and are being installed. This paper reports on tests of these components, including tests of the fiber optic calibration system, detailed studies of electron drift paths on production drift boxes and detectors, tests of the dynamic gating system and its effect on drift path distortions due to space-charge, and a measurement of the electron lifetime in a production drift box. In addition, the authors report on the UV transmission of recirculated liquid freon and on the effects of CRID construction materials on electron lifetime

Component and system tests of the SLD Cerenkov Ring Imaging Detector

International Nuclear Information System (INIS)

Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dasu, S.; Dolinsky, S.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.; Muller, D.; Nagamine, T.; Pavel, T.; Ratcliff, B.; Rensing, P.; Schultz, D.; Shapiro, S.; Simopoulos, C.; Solodov, E.; Toge, N.; Va'vra, J.; Williams, S.; Cavalli-Sforza, M.; Coyle, P.; Coyne, D.; Gagnon, P.; Liu, X.; Williams, D.A.; Whitaker, J.S.; Wilson, R.J.; Bean, A.; Caldwell, D.; Duboscq, J.; Huber, J.; Lu, A.; Mathys, L.; McHugh, S.; Witherell, M.; Yellin, S.; D'Oliveira, A.; Johnson, R.A.; Martinez, J.L.; Meadows, B.; Nussbaum, M.; Santha, A.K.S.; Shoup, A.; Stockdale, I.; Baird, K.; Jacques, P.; Kalelkar, M.; Plano, R.; Stamer, P.; Word, G.; Abe, K.; Hasegawa, K.; Suekane, F.; Yuta, H.

1991-02-01

The components of the SLD barrel Cerenkov Ring Imaging Detector (CRID) are now built and are being installed. We report on tests of these, including tests of the fiber optic calibration system, detailed studies of electron drift paths on production drift boxes and detectors, tests of the dynamic gating system and its effect on drift path distortions due to space-charge, and a measurement of the electron lifetime in a production drift box. In addition, we report on the UV transmission of recirculated liquid C 6 F 14 and on the effects of CRID construction materials on electron lifetime. 9 refs., 11 figs

Component and system tests of the SLD Cerenkov Ring Imaging Detector

International Nuclear Information System (INIS)

Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dasu, S.; Dolinsky, S.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.; Muller, D.; Nagamine, T.; Pavel, T.; Ratcliff, B.; Rensing, P.; Schultz, D.; Shapiro, S.; Simopoulos, C.; Solodov, E.; Toge, N.; Va'vra, J.; Williams, S.; Cavalli-Sforza, M.; Coyle, P.; Coyne, D.; Gagnon, P.; Liu, X.; Williams, D.A.; Whitaker, J.S.; Wilson, R.J.; Bean, A.; Caldwell, D.; Duboscq, J.; Huber, J.; Lu, A.; Mathys, L.; McHugh, S.; Witherell, M.; Yellin, S.; d'Oliveira, A.; Johnson, R.A.; Martinez, J.; Meadows, B.; Nussbaum, M.; Santha, A.K.S.; Shoup, A.; Stockdale, I.; Jacques, P.; Kalelkar, M.; Plano, R.; Stamer, P.; Abe, K.; Hasegawa, K.; Suekane, F.; Yuta, H.

1990-10-01

The components of the SLD barrel Cerenkov Ring Imaging Detector (CRID) are now built and are being installed. We report on tests of these components, including tests of the fiber optic calibration system, detailed studies of electron drift paths on production drift boxes and detectors, tests of the dynamic gating systems and its effect on drift path distortions due to space-charge, and a measurement of the electron lifetime in a production drift box. In addition, we report on the UV transmission of recirculated liquid freon and on the effects of CRID construction materials on electron lifetime. 16 refs., 12 figs

CdZnTe γ detector for deep inelastic neutron scattering on the VESUVIO spectrometer

Science.gov (United States)

Andreani, C.; D'Angelo, A.; Gorini, G.; Imberti, S.; Pietropaolo, A.; Rhodes, N. J.; Schooneveld, E. M.; Senesi, R.; Tardocchi, M.

In this paper it is shown that solid-state cadmium-zinc-telluride (CZT) is a promising photon detector for neutron spectroscopy in a wide energy interval, ranging from thermal ( 25 meV) to epithermal ( 70 eV) neutron energies. In the present study two CZT detectors were tested as part of the inverse-geometry neutron spectrometer VESUVIO operating at the ISIS pulsed neutron source. The response of the CZT detector to photon emission from radiative neutron capture in 238U was determined by biparametric measurements of neutron time of flight and photon energy. The scattering response function F(y) from a Pb sample has been derived using both CZT and conventional 6Li-glass scintillator detectors. The former showed both an improved signal to background ratio and higher efficiency as compared to 6Li glass, allowing us to measure F(y) up to the fourth 238U absorption energy (Er=66.02 eV). Due to the small size of CZT detectors, their use is envisaged in arrays, with high spatial resolution, for neutron-scattering studies at high energy (ω>1 eV) and low wavevector (q <10 Å-1) transfers.

CdZnTe γ detector for deep inelastic neutron scattering on the VESUVIO spectrometer

International Nuclear Information System (INIS)

Andreani, C.; Pietropaolo, A.; Senesi, R.; D'Angelo, A.; Gorini, G.; Imberti, S.; Tardocchi, M.; Rhodes, N.J.; Schooneveld, E.M.

2004-01-01

In this paper it is shown that solid-state cadmium-zinc-telluride (CZT) is a promising photon detector for neutron spectroscopy in a wide energy interval, ranging from thermal (∝25 meV) to epithermal (∝70 eV) neutron energies. In the present study two CZT detectors were tested as part of the inverse-geometry neutron spectrometer VESUVIO operating at the ISIS pulsed neutron source. The response of the CZT detector to photon emission from radiative neutron capture in 238 U was determined by biparametric measurements of neutron time of flight and photon energy. The scattering response function F(y) from a Pb sample has been derived using both CZT and conventional 6 Li-glass scintillator detectors. The former showed both an improved signal to background ratio and higher efficiency as compared to 6 Li glass, allowing us to measure F(y) up to the fourth 238 U absorption energy (E r =66.02 eV). Due to the small size of CZT detectors, their use is envisaged in arrays, with high spatial resolution, for neutron-scattering studies at high energy (ℎω>1 eV) and low wavevector (q -1 ) transfers. (orig.)

A 12-bit SAR ADC integrated on a multichannel silicon drift detector readout IC

Energy Technology Data Exchange (ETDEWEB)

Schembari, F., E-mail: filippo.schembari@polimi.it [Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, via Golgi 40, 20133 Milano (Italy); INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Bellotti, G.; Fiorini, C. [Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, via Golgi 40, 20133 Milano (Italy); INFN, Sezione di Milano, via Celoria 16, 20133 Milano (Italy)

2016-07-11

A 12-bit analog-to-digital converter (ADC) addressed to Silicon-Drift Detectors (SDDs) multichannel readout ASICs for X- and gamma-ray applications is presented. Aiming at digitizing output multiplexed data from the upstream analog filters banks, the converter must ensure 11-bit accuracy and a sampling frequency of about 5 MS/s. The ADC architecture is the charge-redistribution (CR) successive-approximation register (SAR). A fully differential topology has also been chosen for better rejection of common-mode noise and disturbances. The internal DAC is made of binary-scaled capacitors, whose bottom plates are switched by the SAR logic to perform the binary search of the analog input value by means of the monotonic switching scheme. The A/D converter is integrated on SFERA, a multichannel ASIC fabricated in a standard CMOS 0.35 μm 3.3 V technology and it occupies an area of 0.42 mm{sup 2}. Simulated static performance shows monotonicity over the whole input–output characteristic. The description of the circuit topology and of inner blocks architectures together with the experimental characterization is here presented. - Highlights: • X- and γ-ray spectroscopy front-ends need to readout a high number of detectors. • Design efforts are increasingly oriented to compact and low-power ASICs. • A possible solution is the on-chip integration of the analog-to-digital converter. • A 12-bit CR successive-approximation-register ADC has been developed. • It is a suitable candidate as the digitizer to be integrated in multichannel ASICs.

Cerenkov ring imaging detector development at SLAC

International Nuclear Information System (INIS)

Williams, S.H.

1984-06-01

The imaging of Cerenkov light on to photosensitive detectors promises to be a powerful technique for identifying particles in colliding beam spectrometers. Toward this end two and three dimensional imaging photon detectors are being developed at SLAC. The present techniques involve photon conversion using easily ionized exotic chemicals like tetrakisdimethyl-amino-ethylene (TMAE) in a drift and amplifying gas mixture of methane and isobutane. Single photoelectrons from Cerenkov light are currently being drifted 20 cm and a new device under study will be used to study drifting up to 80 cm along a magnetic field. A short description of a large device currently being designed for the SLD spectrometer at the Stanford Linear Collider will be given

Relative efficiency calibration between two silicon drift detectors performed with a monochromatized X-ray generator over the 0.1-1.5 keV range

Science.gov (United States)

Hubert, S.; Boubault, F.

2018-03-01

In this article, we present the first X-ray calibration performed over the 0.1-1.5 keV spectral range by means of a soft X-ray Manson source and the monochromator SYMPAX. This monochromator, based on a classical Rowland geometry, presents the novelty to be able to board simultaneously two detectors and move them under vacuum in front of the exit slit of the monochromatizing stage. This provides the great advantage to perform radiometric measurements of the monochromatic X-ray photon flux with one reference detector while calibrating another X-ray detector. To achieve this, at least one secondary standard must be operated with SYMPAX. This paper presents thereby an efficiency transfer experiment between a secondary standard silicon drift detector (SDD), previously calibrated on BESSY II synchrotron Facility, and another one ("unknown" SDD), devoted to be used permanently with SYMPAX. The associated calibration process is described as well as corresponding results. Comparison with calibrated measurements performed at the Physikalisch-Technische Bundesanstalt (PTB) Radiometric Laboratory shows a very good agreement between the secondary standard and the unknown SDD.

Optimization of drift gases for accuracy in pressurized drift tubes

CERN Document Server

Kirchner, J J; Dinner, A R; Fidkowski, K J; Wyatt, J H

2001-01-01

Modern detectors such as ATLAS use pressurized drift tubes to minimize diffusion and achieve high coordinate accuracy. However, the coordinate accuracy depends on the exact knowledge of converting measured times into coordinates. Linear space-time relationships are best for reconstruction, but difficult to achieve in the $E \\propto \\frac{1}{r}$ field. Previous mixtures, which contained methane or other organic quenchers, are disfavored because of ageing problems. From our studies of nitrogen and carbon dioxide, two mixtures with only small deviations from linearity were determined and measured. Scaling laws for different pressures and magnetic fields are also given.

Optimization of drift gases for accuracy in pressurized drift tubes

International Nuclear Information System (INIS)

Kirchner, J.J.; Becker, U.J.; Dinner, R.B.; Fidkowski, K.J.; Wyatt, J.H.

2001-01-01

Modern detectors such as ATLAS use pressurized drift tubes to minimize diffusion and achieve high coordinate accuracy. However, the coordinate accuracy depends on the exact knowledge of converting measured times into coordinates. Linear space-time relationships are best for reconstruction, but difficult to achieve in the E∝1/r field. Previous mixtures, which contained methane or other organic quenchers, are disfavored because of ageing problems. From our studies of nitrogen and carbon dioxide, two mixtures with only small deviations from linearity were determined and measured. Scaling laws for different pressures and magnetic fields are also given

A novel intermediate layer for Au/CdZnTe/FTO photoconductive structure

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yuelu; Wang, Linjun, E-mail: ljwang@shu.edu.cn; Xu, Run; Huang, Jian; Tao, Jun; Meng, Hua; Zhang, Jijun; Min, Jiahua

2016-12-01

Highlights: • Graphene layer was spin-coated on CdZnTe to form Au/graphene/CdZnTe/FTO structure. • Graphene layer can significantly improve the contact property of Au/CdZnTe. • Graphene layer can obviously enhance UV photo-response of CdZnTe. • Graphene is a potential buffer material for CdZnTe based high-energy detectors. - Abstract: In this work, graphene is tried to use to improve the performance of polycrystalline CdZnTe high-energy radiation and photon detectors. A graphene intermediate layer is prepared by spin-coating process on the surface of polycrystalline CdZnTe film, which forms a photoconductive Au/graphene/CdZnTe/FTO structure. XRD, Raman, photoelectric response and other characterisation methods are adopted to investigate the effect of graphene layer on the electrical characteristics and UV photo-response performance of CdZnTe photoconductive structure. It is demonstrated that graphene layer can significantly improve the contact property of Au/CdZnTe structure, and obviously enhance its UV photo-response and the UV sensitivity increased with one order of magnitude.

Silicon Telescope Detectors

CERN Document Server

Gurov, Yu B; Sandukovsky, V G; Yurkovski, J

2005-01-01

The results of research and development of special silicon detectors with a large active area ($> 8 cm^{2}$) for multilayer telescope spectrometers (fulfilled in the Laboratory of Nuclear Problems, JINR) are reviewed. The detector parameters are listed. The production of totally depleted surface barrier detectors (identifiers) operating under bias voltage two to three times higher than depletion voltage is described. The possibility of fabrication of lithium drifted counters with a very thin entrance window on the diffusion side of the detector (about 10--20 $\\mu$m) is shown. The detector fabrication technique has allowed minimizing detector dead regions without degradation of their spectroscopic characteristics and reliability during long time operation in charge particle beams.

Effect of chemical etching on the surface roughness of CdZnTe and CdMnTe gamma radiation detectors

International Nuclear Information System (INIS)

Hossain, A.; Babalola, S.; Bolotnikov, A.E.; Camarda, G.S.; Cui, Y.; Yang, G.; Guo, M.; Kochanowska, D.; Mycielski, A.; Burger, A.; James, R.B.

2008-01-01

Generally, mechanical polishing is performed to diminish the cutting damage followed by chemical etching to remove the remaining damage on crystal surfaces. In this paper, we detail the findings from our study of the effects of various chemical treatments on the roughness of crystal surfaces. We prepared several CdZnTe (CZT) and CdMnTe (CMT) crystals by mechanical polishing with 5 (micro)m and/or lower grits of Al 2 O 3 abrasive papers including final polishing with 0.05-(micro)m particle size alumina powder and then etched them for different periods with a 2%, 5% Bromine-Methanol (B-M) solution, and also with an E-solution (HNO 3 :H 2 O:Cr 2 O 7 ). The material removal rate (etching rate) from the crystals was found to be 10 (micro)m, 30 (micro)m, and 15 (micro)m per minute, respectively. The roughness of the resulting surfaces was determined by the Atomic Force Microscopy (AFM) to identify the most efficient surface processing method by combining mechanical and chemical polishing

Position-sensitive X-ray detectors

International Nuclear Information System (INIS)

Hendrix, J.

1982-01-01

An overview is given of the different types of position-sensitive X-ray detectors used in kinetic studies of biological molecule state changes using X-ray diffraction with synchrotron radiation as a probe. The detector requirements and principles of operation of proportional counters are outlined. Multiwire proportional chamber systems and their readout techniques are described. Other detectors discussed include a drift chamber type detector, microchannel plates, charge-couple devices and, for high count rates, an integrating TV-detector. (U.K.)

Soudan 2 detector as a time-projection calorimeter

International Nuclear Information System (INIS)

Allison, W.W.M.; Alner, J.; Ambats, I.

1986-01-01

The Soudan 2 Nucleon Decay Detector uses Hytrel plastic tubes to cause ionization electrons to drift up to 50 cm prior to gas multiplication and collection. The drift tubes are embedded in a matrix of thin steel sheets. Readout is accomplished by flash digitizers in a system with distributed intelligence. This design is usable as a general-purpose calorimeter in which 3 spatial coordinates and pulse height are measured at all points where ionization occurs. Several 4.3 ton modules of this detector have now been studied in detail. We will present information about the detector performance and its dependence on manufacturing tolerances

CdZnTe {gamma} detector for deep inelastic neutron scattering on the VESUVIO spectrometer

Energy Technology Data Exchange (ETDEWEB)

Andreani, C.; Pietropaolo, A.; Senesi, R. [Dipartimento di Fisica, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133, Roma (Italy); Istituto Nazionale per la Fisica della Materia, UdR, Tor Vergata (Italy); D' Angelo, A. [Dipartimento di Fisica, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133, Roma (Italy); Istituto Nazionale di Fisica Nucleare, Sezione, Roma II (Italy); Gorini, G.; Imberti, S.; Tardocchi, M. [Dipartimento di Fisica G. Occhialini, Universita degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126, Milano (Italy); Istituto Nazionale per la Fisica della Materia, UdR, Milano-Bicocca (Italy); Rhodes, N.J.; Schooneveld, E.M. [Isis Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, Oxfordshire (United Kingdom)

2004-03-01

In this paper it is shown that solid-state cadmium-zinc-telluride (CZT) is a promising photon detector for neutron spectroscopy in a wide energy interval, ranging from thermal ({proportional_to}25 meV) to epithermal ({proportional_to}70 eV) neutron energies. In the present study two CZT detectors were tested as part of the inverse-geometry neutron spectrometer VESUVIO operating at the ISIS pulsed neutron source. The response of the CZT detector to photon emission from radiative neutron capture in {sup 238}U was determined by biparametric measurements of neutron time of flight and photon energy. The scattering response function F(y) from a Pb sample has been derived using both CZT and conventional {sup 6}Li-glass scintillator detectors. The former showed both an improved signal to background ratio and higher efficiency as compared to {sup 6}Li glass, allowing us to measure F(y) up to the fourth {sup 238}U absorption energy (E{sub r}=66.02 eV). Due to the small size of CZT detectors, their use is envisaged in arrays, with high spatial resolution, for neutron-scattering studies at high energy ({Dirac_h}{omega}>1 eV) and low wavevector (q <10 A{sup -1}) transfers. (orig.)

Characterization of spectrometric photon-counting X-ray detectors at different pitches

International Nuclear Information System (INIS)

Jurdit, M.; Moulin, V.; Ouvrier-Buffet, P.; Verger, L.; Brambilla, A.; Radisson, P.

2017-01-01

There is growing interest in energy-sensitive photon-counting detectors based on high flux X-ray imaging. Their potential applications include medical imaging, non-destructive testing and security. Innovative detectors of this type will need to count individual photons and sort them into selected energy bins, at several million counts per second and per mm 2 . Cd(Zn)Te detector grade materials with a thickness of 1.5 to 3 mm and pitches from 800 μm down to 200 μm were assembled onto interposer boards. These devices were tested using in-house-developed full-digital fast readout electronics. The 16-channel demonstrators, with 256 energy bins, were experimentally characterized by determining spectral resolution, count rate, and charge sharing, which becomes challenging at low pitch. Charge sharing correction was found to efficiently correct X-ray spectra up to 40 × 10 6 incident photons.s −1 .mm −2 .

Study on a drift chamber for high energy experiments

International Nuclear Information System (INIS)

Puget, Maria Augusta Constante

1993-01-01

This work deals with the studies of a multiwire gaseous detector operating as a drift chamber, which will be part of the SELEX spectrometer of the experiment Fermilab E781. A prototype was designed to be built and tested at IFUSP. Results are shown of the analysis of data taken with another similar detector whose construction and test were done at Fermilab, with the aim of studying its characterization and performance. (author)

MUON DETECTOR BARREL DRIFT TUBES (DT)

CERN Multimedia

Fabrizio Gasparini

The DT system is made of 250 chambers, installed in the five wheels of the CMS Iron Yoke. Each wheel is subdivided in 10 sectors of four chambers each. Two sectors per wheel, the top and bottom ones, are equipped with 5 chambers, the large outer MB4s being split in two. The electronics for local, i.e. chamber, readout and generation of trigger primitives sits on Minicrates installed on each chamber (on-detector electronics). The data from each chamber are collected and synchronized by the off-detector electronics, sitting on the Wheel towers and organized per sector. HV and LV are organized per sector and per quarter (3 sectors) of each wheel respectively, DAQ and DCS have one branch per wheel. At the end of the February CMS Week the central wheel was fully operational and the two positive wheels, YB+1 and +2, fully commissioned. They were successfully moved over the vacuum tank and closed against YB0. The negative wheels were still open, with DT commissioning and final LV and DCS cabling being completed ...

Construction and test of new precision drift-tube chambers for the ATLAS muon spectrometer

Energy Technology Data Exchange (ETDEWEB)

Kroha, H., E-mail: kroha@mpp.mpg.de; Kortner, O.; Schmidt-Sommerfeld, K.; Takasugi, E.

2017-02-11

ATLAS muon detector upgrades aim for increased acceptance for muon triggering and precision tracking and for improved rate capability of the muon chambers in the high-background regions of the detector with increasing LHC luminosity. The small-diameter Muon Drift Tube (sMDT) chambers have been developed for these purposes. With half of the drift-tube diameter of the MDT chambers and otherwise unchanged operating parameters, sMDT chambers share the advantages of the MDTs, but have an order of magnitude higher rate capability and can be installed in detector regions where MDT chambers do not fit in. The chamber assembly methods have been optimized for mass production, minimizing construction time and personnel. Sense wire positioning accuracies of 5 μm have been achieved in serial production for large-size chambers comprising several hundred drift tubes. The construction of new sMDT chambers for installation in the 2016/17 winter shutdown of the LHC and the design of sMDT chambers in combination with new RPC trigger chambers for replacement of the inner layer of the barrel muon spectrometer are in progress.

Construction and test of new precision drift-tube chambers for the ATLAS muon spectrometer

Science.gov (United States)

Kroha, H.; Kortner, O.; Schmidt-Sommerfeld, K.; Takasugi, E.

2017-02-01

ATLAS muon detector upgrades aim for increased acceptance for muon triggering and precision tracking and for improved rate capability of the muon chambers in the high-background regions of the detector with increasing LHC luminosity. The small-diameter Muon Drift Tube (sMDT) chambers have been developed for these purposes. With half of the drift-tube diameter of the MDT chambers and otherwise unchanged operating parameters, sMDT chambers share the advantages of the MDTs, but have an order of magnitude higher rate capability and can be installed in detector regions where MDT chambers do not fit in. The chamber assembly methods have been optimized for mass production, minimizing construction time and personnel. Sense wire positioning accuracies of 5 μm have been achieved in serial production for large-size chambers comprising several hundred drift tubes. The construction of new sMDT chambers for installation in the 2016/17 winter shutdown of the LHC and the design of sMDT chambers in combination with new RPC trigger chambers for replacement of the inner layer of the barrel muon spectrometer are in progress.

Hybrid anode for semiconductor radiation detectors

Science.gov (United States)

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

2013-11-19

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

A new large solid angle multi-element silicon drift detector system for low energy X-ray fluorescence spectroscopy

Science.gov (United States)

Bufon, J.; Schillani, S.; Altissimo, M.; Bellutti, P.; Bertuccio, G.; Billè, F.; Borghes, R.; Borghi, G.; Cautero, G.; Cirrincione, D.; Fabiani, S.; Ficorella, F.; Gandola, M.; Gianoncelli, A.; Giuressi, D.; Kourousias, G.; Mele, F.; Menk, R. H.; Picciotto, A.; Rachevski, A.; Rashevskaya, I.; Sammartini, M.; Stolfa, A.; Zampa, G.; Zampa, N.; Zorzi, N.; Vacchi, A.

2018-03-01

Low-energy X-ray fluorescence (LEXRF) is an essential tool for bio-related research of organic samples, whose composition is dominated by light elements. Working at energies below 2 keV and being able to detect fluorescence photons of lightweight elements such as carbon (277 eV) is still a challenge, since it requires in-vacuum operations to avoid in-air photon absorption. Moreover, the detectors must have a thin entrance window and collect photons at an angle of incidence near 90 degrees to minimize the absorption by the protective coating. Considering the low fluorescence yield of light elements, it is important to cover a substantial part of the solid angle detecting ideally all emitted X-ray fluorescence (XRF) photons. Furthermore, the energy resolution of the detection system should be close to the Fano limit in order to discriminate elements whose XRF emission lines are often very close within the energy spectra. To ensure all these features, a system consisting of four monolithic multi-element silicon drift detectors was developed. The use of four separate detector units allows optimizing the incidence angle on all the sensor elements. The multi-element approach in turn provides a lower leakage current on each anode, which, in combination with ultra-low noise preamplifiers, is necessary to achieve an energy resolution close to the Fano limit. The potential of the new detection system and its applicability for typical LEXRF applications has been proved on the Elettra TwinMic beamline.

Electronics for the CMS muon drift tube chambers the read-out minicrate

CERN Document Server

Fernandez Bedoya, Cristina; Oller, Juan Carlos; Willmott, Carlos

2005-01-01

On the Compact Muon Solenoid (CMS) experimentat the Large Hadron Collider (LHC) at the CERN laboratory, the drift tube chambers are responsible for muon detection and precise momentum measurement. In this paper the first level of the read out electronics for these drift tube chambers is described. These drift tube chambers will be located inside the muon barrel detector in the so-called minicrates (MCs), attached to the chambers. The read out boards (ROBs) are the main component of this first level data acquisition system, and they are responsible for the time digitalization related to Level 1 Accept (L1A) trigger of the incoming signals from the front-end electronics, followed by a consequent data merging to the next stages of the data acquisition system. ROBs' architecture and functionality have been exhaustively tested, as well as their capability of operation beyond the expected environmental conditions inside the CMS detector. Due to the satisfactory results obtained, final production of ROBs and their a...

Property of a CZT semiconductor detector for radionuclide identification

International Nuclear Information System (INIS)

Chun, Sung-Dae; Park, Se-Hwan; Ha, Jang Ho; Kang, Sang Mook; Lee, Dong Hoon; Kim, Yong Kyun; Cho, Yun Ho; Kim, Jong Kyung; Hong, Duk-Geun

2008-01-01

Compound semiconductors of high Z value material have been studied intensively for X-ray and γ-ray spectroscopy at room temperature. CdZnTe has wide band gap energy as 1.6 eV and can provide high quantum efficiency with reasonably good energy resolution at room temperature. This study is aimed at determining radionuclide analysis ability by measuring energy resolution of CZT detector which will be applied at nuclear material identification purpose. For experiment we used a CZT detector (5 x 5 x 5 mm 3 ) which is manufactured by eV Products. We have performed our measurement at varied temperatures similar to the outdoor environment for the investigation about temperature dependence of energy resolution and peak centroid fluctuation of CZT detector by using gas cooling and Peltier cooling methods. In order to test radionuclide identification we used various radionuclide samples; plutonium, europium and other standard sources. Pulse height spectra were obtained by standard electronics which consists of a preamplifier, a shaping amplifier, and a multi-channel analyzer. (author)

Silicon drift-chamber studies for possible use at RHIC

International Nuclear Information System (INIS)

Humanic, T.J.

1990-01-01

It is proposed to continue the program now underway at the University of Pittsburgh to study the feasibility of using silicon drift-chambers as particle tracking devices at RHIC. We are currently testing a UA6-type detector obtained from BNL and plan to also study a new device that will become available this year: a cylindrical geometry detector designed for NA45 (CERN). In addition we propose to fabricate and study a detector to be used in vertex determination for the RHIC OASIS experiment. The two-year budget for this proposal is $246.962. 5 refs., 12 figs

Summary of activity. Topic I: detectors and experiments. [High-energy detectors for use at ISABELLE

Energy Technology Data Exchange (ETDEWEB)

Marx, J; Ozaki, S

1978-01-01

Results of a workshop studying detectors for Isabelle experimental halls are described. The detectors must be very reliable. Spatial resolution of the tracking detectors must be high to provide accurate measurements of angle and momentum, retain a short resolving time, and show excellent multiparticle handling capability. Included in the study were hodoscopes, drift chambers, proportional chambers, time projection chambers, Cherenkov counters, electromagnetic shower detectors, and hadron calorimeters. Data handling methods were also included in the studies. (FS)

Silicon drift-chamber studies for possible use at RHIC

International Nuclear Information System (INIS)

Humanic, T.J.

1990-01-01

It is proposed to continue the program now underway at the University of Pittsburgh to study the feasibility of using silicon drift-chambers as particle tracking devices at RHIC. We are currently testing a UA6-type detector obtained from BNL, and propose to also study a new device that will become available this year: a cylindrical geometry detector design for NA45 (CERN). This new detector will be produced at BNL and the MPI-Institute in Munich and will incorporate updated techniques which should result in a reliable device with improved performance over the UA6-type detector. The one-year budget for this proposal is $50,079. 28 refs., 2 figs

CZT Virtual Frisch-grid Detector: Principles and Applications

International Nuclear Information System (INIS)

Cui, Y.; Bolotnikov, A.; Camarda, G.; Hossain, A.; James, R.B.

2009-01-01

Cadmium Zinc Telluride (CdZnTe or CZT) is a very attractive material for using as room-temperature semiconductor detectors, because it has a wide bandgap and a high atomic number. However, due to the material's poor hole mobility, several special techniques were developed to ensure its suitability for radiation detection. Among them, the virtual Frisch-grid CZT detector is an attractive option, having a simple configuration, yet delivering an outstanding spectral performance. The goal of our group in Brookhaven National Laboratory (BNL) is to improve the performance of Frisch-ring CZT detectors; most recently, that effort focused on the non-contacting Frisch-ring detector, allowing us to build an inexpensive, large-volume detector array with high energy-resolution and a large effective area. In this paper, the principles of virtual Frisch-grid detectors are described, especially BNL's innovative improvements. The potential applications of virtual Frisch-grid detectors are discussed, and as an example, a hand-held gamma-ray spectrometer using a CZT virtual Frischgrid detector array is introduced, which is a self-contained device with a radiation detector, readout circuit, communication circuit, and high-voltage supply. It has good energy resolution of 1.4% (FWHM of 662-keV peak) with a total detection volume of ∼20 cm 3 . Such a portable inexpensive device can be used widely in nonproliferation applications, non-destructive detection, radiation imaging, and for homeland security. Extended systems based on the same technology have potential applications in industrial- and nuclear-medical-imaging

Charge sharing and charge loss in a cadmium-zinc-telluride fine-pixel detector array

International Nuclear Information System (INIS)

Gaskin, J.A.; Sharma, D.P.; Ramsey, B.D.

2003-01-01

Because of its high atomic number, room temperature operation, low noise, and high spatial resolution a cadmium-zinc-telluride multi-pixel detector is ideal for hard X-ray astrophysical observation. As part of on-going research at MSFC to develop multi-pixel CdZnTe detectors for this purpose, we have measured charge sharing and charge loss for a 4x4 (750 μm pitch), 1 mm thick pixel array and modeled these results using a Monte-Carlo simulation. This model was then used to predict the amount of charge sharing for a much finer pixel array (with a 300 μm pitch). Future work will enable us to compare the simulated results for the finer array to measured values

Simulation of single-event energy-deposition spreading in a hybrid pixellated detector for gamma imaging

CERN Document Server

Manach, E

2002-01-01

In the framework of the Medipix2 Collaboration, a new photon-counting chip is being developed made of a 256x256 array of 55 mu m-side square pixels. Although the chip was primarily developed for semiconductor X-ray imagers, we think that this type of device could be used in applications such as decommissioning of nuclear facilities where typical sources have gamma-ray energies in the range of a few hundred keV. In order to enhance the detection efficiency in this energy range, we envisage connecting the Medipix2 chip to a CdTe or CdZnTe substrate (at least 1 mm thick). The small pixel size, the thickness of the Cd(Zn)Te substrate and the high photon energy motivate us to estimate first the spatial energy spreading following a photon interaction inside the detector. Estimations were made using the MCNP Monte Carlo package by simulating the individual energy distribution for each primary photon interaction. As an illustration of our results, simulating a 660 keV gamma source, we found that there are two pixels ...

Behaviour of large cylindrical drift chambers in a superconducting solenoid

International Nuclear Information System (INIS)

Boer, W. de; Fues, W.; Grindhammer, G.; Kotthaus, R.; Lierl, H.; Moss, L.

1980-04-01

We describe the construction and behaviour of a set of cylindrical drift chambers operating inside a superconducting solenoid with a central magnetic field of 1.3 T. The chambers are part of the 4 π detector CELLO at the e + e - storage ring PETRA in Hamburg. The chambers were designed without field shaping to keep them as simple as possible. In order to parametrize accurately the nonlinear space-time relation, we used a computer simulation of the drift process in inhomogenous electric and magnetic fields. With such a parametrization we achieved a resolution of 210 μm, averaged over the whole drift cell and angles of incidence up to 30 0 . (orig.)

Pulse-height loss in the signal readout circuit of compound semiconductor detectors

Science.gov (United States)

Nakhostin, M.; Hitomi, K.

2018-06-01

Compound semiconductor detectors such as CdTe, CdZnTe, HgI2 and TlBr are known to exhibit large variations in their charge collection times. This paper considers the effect of such variations on the measurement of induced charge pulses by using resistive feedback charge-sensitive preamplifiers. It is shown that, due to the finite decay-time constant of the preamplifiers, the capacitive decay during the signal readout leads to a variable deficit in the measurement of ballistic signals and a digital pulse processing method is employed to correct for it. The method is experimentally examined by using sampled pulses from a TlBr detector coupled to a charge-sensitive preamplifier with 150 μs of decay-time constant and 20 % improvement in the energy resolution of the detector at 662 keV is achieved. The implications of the capacitive decay on the correction of charge-trapping effect by using depth-sensing technique are also considered.

Trigger drift chamber for the MKII upgrade at PEP

International Nuclear Information System (INIS)

Ford, W.T.

1984-06-01

The design and fabrication work for the small trigger drift chamber are now advanced enough to permit a fairly detailed specification of this device as it will appear for installation in the detector next fall. This note contains a description of the trigger chamber design

Three-dimensional points from PWC's and drift chambers

International Nuclear Information System (INIS)

Kramer, M.A.

1977-01-01

Two aspects of the high event rates anticipated at ISABELLE are, first, the need for sophisticated triggers to select interesting events and, second, the enormous data reduction capabilities that will be required. It was concluded that both of these problems must be considered in the design of the detectors. A description is given of some of the advantages that a PWC or drift chamber system that provides correlated x-y readouts would provide, and a scheme for implementing such a detector with adequate spatial and rate capabilities is discussed

Control method and device for automatic drift stabilization in radiation detection

International Nuclear Information System (INIS)

Berthold, F.; Kubisiak, H.

1979-01-01

In the automatic control circuit individual electron peaks in the detectors, e.g. NaI crystals or proportional counters, are used. These peaks exhibit no drift dependence; they may be produced in the detectors in different ways. The control circuit may be applied in nuclear radiation measurement techniques, photometry, gamma cameras and for measuring the X-ray fine structure with proportional counters. (DG) [de

Pulse shape simulation for drift chambers with long drift paths

Energy Technology Data Exchange (ETDEWEB)

Mayer, H J

1987-09-15

A detailed Monte Carlo program for the simulation of drift chamber pulse shapes is described. It has been applied to the case of a jet chamber with drift paths up to 24 cm. Results on pulse shapes and corresponding spatial and double hit resolution are discussed and compared to recent measurements of the OPAL central detector jet chamber full size prototype and to measurements of a small 20-wire prototype, which was designed to study the pulse shapes generated by tracks in a magnetic field. Simulated pulse shapes and spatial resolutions agree well with the experimental data. Clustering, saturation and wire crosstalk are shown to be necessary ingredients in the simulation. A deterioration in resolution due to the influence of crosstalk signals is correctly reproduced, as well as the cancellation of this effect by a hardwired first and second neighbour crosstalk compensation. The simulation correctly describes the asymmetry in spatial resolution observed for tracks with positive or negative inclination against the wire plane when a magnetic field is present. The effect of saturation on double hit resolution is found to be small. The magnetic field is predicted to improve the double hit resolution.

Pulse shape simulation for drift chambers with long drift paths

International Nuclear Information System (INIS)

Mayer, H.J.

1987-01-01

A detailed Monte Carlo program for the simulation of drift chamber pulse shapes is described. It has been applied to the case of a jet chamber with drift paths up to 24 cm. Results on pulse shapes and corresponding spatial and double hit resolution are discussed and compared to recent measurements of the OPAL central detector jet chamber full size prototype and to measurements of a small 20-wire prototype, which was designed to study the pulse shapes generated by tracks in a magnetic field. Simulated pulse shapes and spatial resolutions agree well with the experimental data. Clustering, saturation and wire crosstalk are shown to be necessary ingredients in the simulation. A deterioration in resolution due to the influence of crosstalk signals is correctly reproduced, as well as the cancellation of this effect by a hardwired first and second neighbour crosstalk compensation. The simulation correctly describes the asymmetry in spatial resolution observed for tracks with positive or negative inclination against the wire plane when a magnetic field is present. The effect of saturation on double hit resolution is found to be small. The magnetic field is predicted to improve the double hit resolution. (orig.)

On the Role of Boron in CdTe and CdZnTe Crystals

Science.gov (United States)

Pavesi, M.; Marchini, L.; Zha, M.; Zappettini, A.; Zanichelli, M.; Manfredi, M.

2011-10-01

It is well known that group III elements act as donors if they play a substitutional role at the metallic site in II-tellurides; nevertheless, several studies report both on the creation of complexes with vacancies, named A-centers, and on the involvement in self-compensation mechanisms, especially for indium. The boron concentration in II-tellurides is negligible, and its contribution to transport mechanisms has not been studied yet. For the last few years the authors have been developing a new technique to grow CdZnTe by the vertical Bridgman technique, taking advantage of encapsulation by means of boron oxide. In this way, crystals characterized by large single grains, low etch pit density, and high resistivity have been obtained. Recently, x-ray detectors with state-of-the-art performance have been produced from such crystals. Boron contamination, as a consequence of this growth method, is quite low but at least one order of magnitude above values obtained with other growth techniques. Besides being a low-cost technique which is also suitable for large-scale mass production, the encapsulated vertical Bridgman technique is quite useful to prevent dislocations, grain boundaries, and stacking faults; for these reasons, careful characterization was performed to understand the effect of boron both on the electrical properties and on the spectroscopic performance of the final crystals. Our characterization is mainly based on low-temperature photoluminescence in addition to electrical current-voltage measurements, photostimulated current, and x-ray spectroscopy. The results indicate that boron behaves like other group III elements; in fact, boron forms a complex that does not affect the good performance of our x-ray detectors, even if it shows some properties which are typical of A-centers.

A compact 7-cell Si-drift detector module for high-count rate X-ray spectroscopy.

Science.gov (United States)

Hansen, K; Reckleben, C; Diehl, I; Klär, H

2008-05-01

A new Si-drift detector module for fast X-ray spectroscopy experiments was developed and realized. The Peltier-cooled module comprises a sensor with 7 × 7-mm 2 active area, an integrated circuit for amplification, shaping and detection, storage, and derandomized readout of signal pulses in parallel, and amplifiers for line driving. The compactness and hexagonal shape of the module with a wrench size of 16mm allow very short distances to the specimen and multi-module arrangements. The power dissipation is 186mW. At a shaper peaking time of 190 ns and an integration time of 450 ns an electronic rms noise of ~11 electrons was achieved. When operated at 7 °C, FWHM line widths around 260 and 460 eV (Cu-K α ) were obtained at low rates and at sum-count rates of 1.7 MHz, respectively. The peak shift is below 1% for a broad range of count rates. At 1.7-MHz sum-count rate the throughput loss amounts to 30%.

Development of Silicon Drift Detectors using Boron layer technology

NARCIS (Netherlands)

Golshani, N.

2015-01-01

Radiation detectors are used in a large variety of fields such as medicine, security, defense, geophysics, industry and physics. They have been developed to detect the energy or position of radiation or charge particles. In Chapter 1 several X-ray detectors were introduced briefly. In gas filled

Correlated analysis of 2 MeV proton-induced radiation damage in CdZnTe crystals using photoluminescence and thermally stimulated current techniques

Energy Technology Data Exchange (ETDEWEB)

Gu, Yaxu [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Key Laboratory of Radiation Detection Materials and Devices of Ministry of Industry and Information Technology, Northwestern Polytechnical University, Xi’an 710072 (China); Jie, Wanqi, E-mail: jwq@nwpu.edu.cn [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Key Laboratory of Radiation Detection Materials and Devices of Ministry of Industry and Information Technology, Northwestern Polytechnical University, Xi’an 710072 (China); Rong, Caicai [Institute of Modern Physics, Applied Ion Beam Physics Laboratory, Fudan University, Shanghai 200433 (China); Wang, Yuhan; Xu, Lingyan; Xu, Yadong [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Key Laboratory of Radiation Detection Materials and Devices of Ministry of Industry and Information Technology, Northwestern Polytechnical University, Xi’an 710072 (China); Lv, Haoyan; Shen, Hao [Institute of Modern Physics, Applied Ion Beam Physics Laboratory, Fudan University, Shanghai 200433 (China); Du, Guanghua [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Fu, Xu [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Key Laboratory of Radiation Detection Materials and Devices of Ministry of Industry and Information Technology, Northwestern Polytechnical University, Xi’an 710072 (China); and others

2016-11-01

Highlights: • 2 MeV proton-induced radiation damage in CdZnTe crystals is investigated by PL and TSC techniques. • The influence of radiation damage on the luminescent and electrical properties of CdZnTe crystals is studied. • Intensity of PL spectrum is found to decrease significantly in irradiated regions, suggesting the increase of non-radiative recombination centers. • A correlated analysis of PL and TSC spectra suggests that the density of dislocations and A-centers increase after proton irradiation. - Abstract: Radiation damage induced by 2 MeV protons in CdZnTe crystals has been studied by means of photoluminescence (PL) and thermally stimulated current (TSC) techniques. A notable quenching of PL intensity is observed in the regions irradiated with a fluence of 6 × 10{sup 13} p/cm{sup 2}, suggesting the increase of non-radiative recombination centers. Moreover, the intensity of emission peak D{sub complex} centered at 1.48 eV dominates in the PL spectrum obtained from irradiated regions, ascribed to the increase of interstitial dislocation loops and A centers. The intensity of TSC spectra in irradiated regions decreases compared to the virgin regions, resulting from the charge collection inefficiency caused by proton-induced recombination centers. By comparing the intensity of identified traps obtained from numerical fitting using simultaneous multiple peak analysis (SIMPA) method, it suggests that proton irradiation under such dose can introduce high density of dislocation and A-centers in CdZnTe crystals, consistent with PL results.

Characterization of CdTe and (CdZn)Te detectors with different metal contacts

Science.gov (United States)

Pekárek, J.; Belas, E.; Grill, R.; Uxa, Å.; James, R. B.

2013-09-01

In the present work we studied an influence of different types of surface etching and surface passivation of high resistivity CdZnTe-based semiconductor detector material. The aim was to find the optimal conditions to improve the properties of metal-semiconductor contact. The main effort was to reduce the leakage current and thus get better X-ray and gamma-ray spectrum, i.e. to create a detector operating at room temperature based on this semiconductor material with sufficient energy resolution and the maximum charge collection efficiency. Individual surface treatments were characterized by I-V characteristics, spectral analysis and by determination of the profile of the internal electric field.

Characterization of etch pit formation via the Everson-etching method on CdZnTe crystal surfaces from the bulk to the nanoscale

International Nuclear Information System (INIS)

Teague, Lucile C.; Duff, Martine C.; Cadieux, James R.; Soundararajan, Raji; Shick, Charles R.; Lynn, Kelvin G.

2011-01-01

A combination of atomic force microscopy, optical microscopy, and mass spectrometry was employed to study CdZnTe crystal surface and used etchant solution following exposure of the CdZnTe crystal to the Everson etch solution. We discuss the results of these studies in relationship to the initial surface preparation methods, the performance of the crystals as radiation spectrometers, the observed etch pit densities, and the chemical mechanism of surface etching. Our results show that the surface features that are exposed to etchants result from interactions with the chemical components of the etchants as well as pre-existing mechanical polishing.

Track finding and track reconstruction in the internal forward drift chamber of SAPHIR

International Nuclear Information System (INIS)

Umlauf, G.

1993-03-01

A track finding algorithm has been developed for the inner forward drift chamber of the SAPHIR detector (at ELSA in Bonn) using the Principal Components Analysis as a tool for interpolating track coordinates. The drift chamber consists of twelve planar layers with six different inclinations and is being operated in an inhomogenous magnetic field. The task of track finding is basicly split into a primary stage that defines track candidates without the use of drift-time information and a second stage that serves to verify the track candidate and to resolve the intrinsic left-right ambiguities of the drift chamber signals. Tracks with at most three missing signals can be found. (orig.) [de

Contribution to Diogene detector drift chambers study

International Nuclear Information System (INIS)

Drouet, M.

1981-06-01

Diogene detector has been brought into operation at Saclay with the collaboration of Strasbourg CRN and Clermont-Ferrand LPC. The Diogene essential characteristic is its solid angle near four pi, allowing complete exclusive measurements. Diogene characteristics allow to detect an important multiplicity of charged particles in coincidence, to measure their impulse until a transverse impulse around 1 GeV/c, and to identify them by their energy loss measurement. These general characteristics are exposed after some brief recalls on charged particle detection and migration counters. Technical aspects of the prototype are examined. It has been built to test fabrication technology, choice exactness and performance estimation validity. These detector performance estimation calculations that may be waited for in tracks reconstruction, impulse and energy loss resolution are exposed. Before, the electrostatics study for the prototype is reviewed. The temporary balance of already carried out tests is made [fr

Lorentz angle studies for the SLD endcap Cerenkov Ring Imaging Detector

International Nuclear Information System (INIS)

Coyle, P.; Cavalli-Sforza, M.; Coyne, D.

1987-11-01

The design of the endcap Cerenkov Ring Imaging Detectors for SLD requires a detailed understanding of how electrons drift in gases under the influence of crossed electric and magnetic fields. In this report, we present recent measurements of Lorentz angles and drift velocities in gases suitable for the endcap CRID photon detectors. We compare these measurements to predictions from a theoretical model; good agreement is observed. Based on our results we present a design for detectors operating in a 0.6 Tesla transverse magnetic field. 14 refs., 10 figs., 4 tabs

Data acquisition and detector characterization of GEO600

International Nuclear Information System (INIS)

Koetter, K; Aulbert, C; Babak, S; Balasubramanian, R; Berukoff, S; Bose, S; Churches, D; Colacino, C N; Cutler, C; Danzmann, K; Davies, R; Dupuis, R; Freise, A; Grote, H; Heinzel, G; Hewitson, M; Hough, J; Lueck, H; Malec, M; Mohanty, S D; Mukherjee, S; Nagano, S; Papa, M A; Robertson, D; Sathyaprakash, B S; Schutz, B F; Sintes, A M; Strain, K A; Taylor, I J; Vecchio, A; Ward, H; Weiland, U; Willke, B; Woan, G

2002-01-01

The data acquisition system of the gravitational wave detector GEO600 is recording the first data now. Data from detector subsystems and environmental channels are being acquired. The data acquisition system is described and first results from the detector characterization work are being presented. We analysed environmental influences on the detector to determine noise propagation through the detector. Long-term monitoring allowed us to see long-timescale drifts in subsystems

Drift chamber and pulse height readout systems using analog multiplexing

International Nuclear Information System (INIS)

Cisneros, E.L; Kang, H.K.; Hall, J.N.; Larsen, R.S.

1976-11-01

Drift chamber and pulse-height readout systems are being developed for use in a new large scale detector at the SPEAR colliding beam facility. The systems are based upon 32 channels of sample-and-hold together with an analog multiplexer in a single-width CAMAC module. The modules within each crate are scanned by an autonomous controller containing a single ADC and memory plus arithmetic capability for offset, gain and linearity corrections. The drift chamber module has a facility for extracting hit wire information for use in trigger decision circuitry

Monitoring methods of drift chamber characteristics. Application to SPES III detection

International Nuclear Information System (INIS)

Kerboul, C.

1984-05-01

For the SPES III spectrometer at the Laboratoire National Saturne, a large detection system has been developed which consists of three drift chambers for localization of the particle trajectories. Performances of these detectors for high spatial resolution depend greatly on different parameters such as anode current, gas mixture, drift velocity, efficiency, etc. The present work summarizes a set of methods necessary to the control of these parameters, for achieving the high resolution essentiel for the nuclear physic at intermediate energy [fr

Simultaneous hit finding and timing method for pulse shape analysis of drift chamber signals

Energy Technology Data Exchange (ETDEWEB)

Schaile, D; Schaile, O; Schwarz, J

1986-01-01

An algorithm for the analysis of the digitized signal waveform of drift chamber pulses is described which yields a good multihit resolution and an accurate drift time determination with little processing time. The method has been tested and evaluated with measured pulse shapes from the full size prototype of the OPAL central detector which were digitized by 100 MHz FADCs. (orig.).

Simultaneous hit finding and timing method for pulse shape analysis of drift chamber signals

Energy Technology Data Exchange (ETDEWEB)

Schaile, D; Schaile, O; Schwarz, J

1986-01-01

An algorithm for the analysis of the digitized signal waveform of drift chamber pulses is described which yields a good multihit resolution and an accurate drift time determination with little processing time. The method has been tested and evaluated with measured pulse shapes from the full size prototype of the OPAL central detector which were digitized by 100 MHz FADCs.

The effect of cathode bias (field effect) on the surface leakage current of CdZnTe detectors

International Nuclear Information System (INIS)

Bolotnikov, A.E.; Hubert Chen, C.M.; Cook, W.R.; Harrison, F.A.; Kuvvetli, I.; Schindler, S.M.; Stahle, C.M.; Parker, B.H.

2003-01-01

Surface resistivity is an important parameter of multi-electrode CZT detectors such as coplanar-grid, strip, or pixel detectors. Low surface resistivity results in a high leakage current and affects the charge collection efficiency in the areas near contacts. Thus, it is always desirable to have the surface resistivity of the detector as high as possible. In the past the most significant efforts were concentrated to develop passivation techniques for CZT detectors. However, as we found, the field-effect caused by a bias applied on the cathode can significantly reduce the surface resistivity even though the detector surface was carefully passivated. In this paper we illustrate that the field-effect is a common feature of the CZT multi-electrode detectors, and discuss how to take advantage of this effect to improve the surface resistivity of CZT detectors

Simulation of 1.5-mm-thick and 15-cm-diameter gated silicon drift X-ray detector operated with a single high-voltage source

Science.gov (United States)

Matsuura, Hideharu

2015-04-01

High-resolution silicon X-ray detectors with a large active area are required for effectively detecting traces of hazardous elements in food and soil through the measurement of the energies and counts of X-ray fluorescence photons radially emitted from these elements. The thicknesses and areas of commercial silicon drift detectors (SDDs) are up to 0.5 mm and 1.5 cm2, respectively. We describe 1.5-mm-thick gated SDDs (GSDDs) that can detect photons with energies up to 50 keV. We simulated the electric potential distributions in GSDDs with a Si thickness of 1.5 mm and areas from 0.18 to 168 cm2 at a single high reverse bias. The area of a GSDD could be enlarged simply by increasing all the gate widths by the same multiple, and the capacitance of the GSDD remained small and its X-ray count rate remained high.

Allpix$^{2}$: A Modular Simulation Framework for Silicon Detectors

CERN Document Server

Spannagel, Simon; Hynds, Daniel; Alipour Tehrani, Niloufar; Benoit, Mathieu; Dannheim, Dominik; Gauvin, Neal; Nurnberg, Andreas Matthias; Schutze, Paul Jean; Vicente Barreto Pinto, Mateus

2018-01-01

Allpix$^{2}$ is a generic, open-source software framework for the simulation of silicon pixel detectors. Its goal is to ease the implementation of detailed simulations for both single detectors and more complex setups such as beam telescopes from incident radiation to the digitised detector response. Predefined detector types can be automatically constructed from simple model files describing the detector parameters. The simulation chain is arranged with the help of intuitive configuration files and an extensible system of modules, which implement separate simulation steps such as realistic charge carrier deposition with the Geant4 toolkit or propagation of charge carriers in silicon using a drift-diffusion model. Detailed electric field maps imported from TCAD simulations can be used to precisely model the drift behaviour of charge carriers within the silicon, bringing a new level of realism to Monte Carlo based simulations of particle detectors. This paper provides an overview of the framework and a select...

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

International Nuclear Information System (INIS)

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

2002-01-01

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

UA1 prototype detector

CERN Multimedia

1980-01-01

Prototype of UA1 central detector inside a plexi tube. The UA1 experiment ran at CERN's Super Proton Synchrotron and made the Nobel Prize winning discovery of W and Z particles in 1983. The UA1 central detector was crucial to understanding the complex topology of proton-antiproton events. It played a most important role in identifying a handful of Ws and Zs among billions of collisions. The detector was essentially a wire chamber - a 6-chamber cylindrical assembly 5.8 m long and 2.3 m in diameter, the largest imaging drift chamber of its day. It recorded the tracks of charged particles curving in a 0.7 Tesla magnetic field, measuring their momentum, the sign of their electric charge and their rate of energy loss (dE/dx). Atoms in the argon-ethane gas mixture filling the chambers were ionised by the passage of charged particles. The electrons which were released drifted along an electric field shaped by field wires and were collected on sense wires. The geometrical arrangement of the 17000 field wires and 6...

Study of drift tube resolution using numerical simulations

International Nuclear Information System (INIS)

Lundin, M.C.

1990-01-01

The results off a simulation of straw tube detector response are presented. These gas ionization detectors and the electronics which must presumably go along with them are characterized in a simple but meaningful manner. The physical processes which comprise the response of the individual straw tubes are broken down and examined in detail. Different parameters of the simulation are varied and resulting predictions of drift tube spatial resolution are shown. In addition, small aspects of the predictions are compared to recent laboratory results, which can be seen as a measure of the simulation's usefulness. 10 refs., 8 figs

Lithium germanium detectors reactivation

International Nuclear Information System (INIS)

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

1981-01-01

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

Precise muon drift tube detectors for high background rate conditions

CERN Document Server

Engl, Albert; Dünnweber, Wolfgang

The muon spectrometer of the ATLAS-experiment at the Large H adron Collider consists of drift tube chambers, which provide the precise m easurement of trajec- tories of traversing muons. In order to determine the moment um of the muons with high precision, the measurement of the position of the m uon in a single tube has to be more accurate than σ ≤ 100 m. The large cross section of proton-proton-collisions and th e high luminosity of the accelerator cause relevant background of neutrons and γ s in the muon spectrome- ter. During the next decade a luminosity upgrade [1] to 5 10 34 cm − 2 s − 1 is planned, which will increase the background counting rates consider ably. In this context this work deals with the further development of the existing drift chamber tech- nology to provide the required accuracy of the position meas urement under high background conditions. Two approaches of improving the dri ft tube chambers are described: • In regions of moderate background rates a faster and more lin ear ...

Radiation damage measurements on CZT drift strip detectors

DEFF Research Database (Denmark)

Kuvvetli, Irfan; Budtz-Jørgensen, Carl; Korsbech, Uffe C C

2003-01-01

from 2 x 10(8) to 60 x 10(8) p(+)/cm(2). Even for the highest fluences, which had a dramatic effect on the spectroscopic performance, we were able to recover the detectors after an appropriate annealing procedure. The radiation damage was studied as a function of depth inside the detector material...... with the proton dose. The radiation contribution to the electron trapping was found to obey the following relation: (mutau(e)(-1))(rad) = (2.5+/-0.2) x 10(-7) x Phi (V/cm)(2) with the proton fluence, Phi in p(+)/cm(2). The trapping depth dependence, however, did not agree well with the damage profile calculated...

Characteristics of a delay-line readout in a cylindrical drift chamber system

International Nuclear Information System (INIS)

Barber, R.; Ahmed, M.W.; Dzemidzic, M.; Empl, A.; Hungerford, E.V.; Lan, K.J.; Wilson, J.; Cooper, M.D.; Gagliardi, C.A.; Haim, D.; Kim, G.J.; Koetke, D.D.; Tribble, R.E.; Van Ausdeln, L.A.

2002-01-01

This paper reports on the design, construction, and operational characteristics of a delay-line readout implemented on the cathode foils of a cylindrical drift chamber system. The readout was used to determine the position of an event along the length of the 1.74 m drift wires in the MEGA detectors used at the Los Alamos Meson Physics Facility. The performance of the system is interpreted by comparison to a PSPICE simulation, and to simple analytical models

The Effect of Amplifier Bias Drift on Differential Magnitude Estimation in Multiple-Star Systems

Science.gov (United States)

Tyler, David W.; Muralimanohar, Hariharan; Borelli, Kathy J.

2007-02-01

We show how the temporal drift of CCD amplifier bias can cause significant relative magnitude estimation error in speckle interferometric observations of multiple-star systems. When amplifier bias varies over time, the estimation error arises if the time between acquisition of dark-frame calibration data and science data is long relative to the timescale over which the bias changes. Using analysis, we show that while detector-temperature drift over time causes a variation in accumulated dark current and a residual bias in calibrated imagery, only amplifier bias variations cause a residual bias in the estimated energy spectrum. We then use telescope data taken specifically to investigate this phenomenon to show that for the detector used, temporal bias drift can cause residual energy spectrum bias as large or larger than the mean value of the noise energy spectrum. Finally, we use a computer simulation to demonstrate the effect of residual bias on differential magnitude estimation. A supplemental calibration technique is described in the appendices.

The GlueX central drift chamber: Design and performance

International Nuclear Information System (INIS)

Van Haarlem, Y.; Meyer, C.A.; Barbosa, F.; Dey, B.; Lawrence, D.; Razmyslovich, V.; Smith, E.; Visser, G.; Whitlatch, T.; Wilkin, G.; Zihlmann, B.

2010-01-01

Tests and studies concerning the design and performance of the GlueX Central Drift Chamber (CDC) are presented. A full-scale prototype was built to test and steer the mechanical and electronic design. Small scale prototypes were constructed to test for sagging and to do timing and resolution studies of the detector. These studies were used to choose the gas mixture and to program a Monte Carlo simulation that can predict the detector response in an external magnetic field. Particle identification and charge division possibilities were also investigated.

A pixellated γ-camera based on CdTe detectors clinical interests and performances

International Nuclear Information System (INIS)

Chambron, J.; Arntz, Y.; Eclancher, B.; Scheiber, Ch.; Siffert, P.; Hage Hali, M.; Regal, R.; Kazandjian, A.; Prat, V.; Thomas, S.; Warren, S.; Matz, R.; Jahnke, A.; Karman, M.; Pszota, A.; Nemeth, L.

2000-01-01

A mobile gamma camera dedicated to nuclear cardiology, based on a 15 cmx15 cm detection matrix of 2304 CdTe detector elements, 2.83 mmx2.83 mmx2 mm, has been developed with a European Community support to academic and industrial research centres. The intrinsic properties of the semiconductor crystals - low-ionisation energy, high-energy resolution, high attenuation coefficient - are potentially attractive to improve the γ-camera performances. But their use as γ detectors for medical imaging at high resolution requires production of high-grade materials and large quantities of sophisticated read-out electronics. The decision was taken to use CdTe rather than CdZnTe, because the manufacturer (Eurorad, France) has a large experience for producing high-grade materials, with a good homogeneity and stability and whose transport properties, characterised by the mobility-lifetime product, are at least 5 times greater than that of CdZnTe. The detector matrix is divided in 9 square units, each unit is composed of 256 detectors shared in 16 modules. Each module consists in a thin ceramic plate holding a line of 16 detectors, in four groups of four for an easy replacement, and holding a special 16 channels integrated circuit designed by CLRC (UK). A detection and acquisition logic based on a DSP card and a PC has been programmed by Eurorad for spectral and counting acquisition modes. Collimators LEAP and LEHR from commercial design, mobile gantry and clinical software were provided by Siemens (Germany). The γ-camera head housing, its general mounting and the electric connections were performed by Phase Laboratory (CNRS, France). The compactness of the γ-camera head, thin detectors matrix, electronic readout and collimator, facilitates the detection of close γ sources with the advantage of a high spatial resolution. Such an equipment is intended to bedside explorations. There is a growing clinical requirement in nuclear cardiology to early assess the extent of an infarct

An algorithm for calculating the Lorentz angle in silicon detectors [online

OpenAIRE

Bartsch, Valeria; De Boer, Willem; Bol, Johannes; Dierlamm, Alexander; Grigoriev, Eugene; Hauler, Florian; Heising, Stephan; Jungermann, Levin

2001-01-01

The CMS (Compact Muon Solenoid) detector will use silicon sensors in the harsh radiation environment of the LHC (Large Hadron Collider) and high magnetic fields. The drift direction of the charge carriers is aected by the Lorentz force due to the high magnetic field. Also the resulting radiation damage changes the properties of the drift. The CMS silicon strip detector is read out on the p-side of the sensors, where holes are coll...

A new TXRF vacuum chamber with sample changer for chemical analysis using silicon drift chamber detector

International Nuclear Information System (INIS)

Streli, C.; Wobrauschek, P.; Zoeger, N.; Pepponi, G.

2003-01-01

Full text: Several TXRF spectrometers for chemical analysis as well as for wafer surface analysis are commercially available. But there is no one available for chemical analysis offering the possibility to measure the samples in vacuum conditions. Vacuum of 10 -2 mbar in the sample environment helps to reduce the background due to scattering from air, thus to improve the detection limits as well as to reduce the absorption of low energy fluorescence radiation from low Z elements and extend the elemental range to be measured and removes the Ar lines from the spectrum. The x-ray group of the Atominstitut designed and fabricated a new vacuum chamber for TXRF equipped with a 12 position sample changer from Italstructures, Riva, Italy. The detector used was a 10 mm 2 silicon drift detector (KETEK, Munich, Germany), offering the advantage of electrically cooling, so no LN2 is required. The chamber was designed to be attached to a diffraction tube housing, e.g. with a fine focus Mo-x-ray tube and uses a multilayer monochromator. Spectra are stored by a small AMTEK MCA and control between sample changer and MCA communication is done by a modified AMPTEK software. The performance is expressed in detection limits of 1 pg Rb for Mo Ka excitation with 50 kV, 40 mA excitation conditions, 1000 s lifetime, obtained from a sample containing 600 pg Rb as single element standard. Details on performance, reproducibility and light element excitation and detection are presented. (author)

Pulse height measurements and electron attachment in drift chambers operated with Xe,CO2 mixtures

CERN Document Server

Andronic, A

2003-01-01

We present pulse height measurements in drift chambers operated with Xe,CO2 gas mixtures. We investigate the attachment of primary electrons on oxygen and SF6 contaminants in the detection gas. The measurements are compared with simulations of properties of drifting electrons. We present two methods to check the gas quality: gas chromatography and Fe55 pulse height measurements using monitor detectors.

Pulse height measurements and electron attachment in drift chambers operated with Xe,CO2 mixtures

International Nuclear Information System (INIS)

Andronic, A.; Appelshaeuser, H.; Blume, C.; Braun-Munzinger, P.; Bucher, D.; Busch, O.; Ramirez, A.C.A. Castillo; Catanescu, V.; Ciobanu, M.; Daues, H.; Devismes, A.; Emschermann, D.; Fateev, O.; Garabatos, C.; Herrmann, N.; Ivanov, M.; Mahmoud, T.; Peitzmann, T.; Petracek, V.; Petrovici, M.; Reygers, K.; Sann, H.; Santo, R.; Schicker, R.; Sedykh, S.; Shimansky, S.; Simon, R.S.; Smykov, L.; Soltveit, H.K.; Stachel, J.; Stelzer, H.; Tsiledakis, G.; Vulpescu, B.; Wessels, J.P.; Windelband, B.; Winkelmann, O.; Xu, C.; Zaudtke, O.; Zanevsky, Yu.; Yurevich, V.

2003-01-01

We present pulse height measurements in drift chambers operated with Xe,CO 2 gas mixtures. We investigate the attachment of primary electrons on oxygen and SF 6 contaminants in the detection gas. The measurements are compared with simulations of properties of drifting electrons. We present two methods to check the gas quality: gas chromatography and 55 Fe pulse height measurements using monitor detectors

Recent developments for the pattern recognition in the central drift chamber of the Belle II detector

Energy Technology Data Exchange (ETDEWEB)

Trusov, Viktor; Feindt, Michael; Heck, Martin; Hauth, Thomas; Goldenzweig, Pablo [Karlsruhe Institute of Technology (Germany); Collaboration: Belle II-Collaboration

2016-07-01

The Belle II experiment is designed to perform more precise measurements (e.g. C P-violation measurements, New Physics phenomena, rare decays etc) than its predecessor, the Belle experiment. To achieve this goal, the luminosity of the experiment will be increased by a factor of 40 and as result multiple times more data will be collected. Due to this fact, faster reconstruction algorithms for the data processing need to be developed and at the same time accurate physical results should be retained. One important part in the data processing chain is the track reconstruction section. We present the development of one of the pattern recognition algorithms for the Belle II experiment based on conformal and Legendre transformations. In order to optimize the performance of the algorithm (CPU time and efficiency) we have introduced specialized processing steps. To show improvements in the results we introduce efficiency measurements of the tracking algorithms in the Central Drift Chamber (CDC) which were done using Monte-Carlo simulation of e{sup +} e{sup -} collisions followed by a full simulation of the Belle II detector.

The DELPHI Detector (DEtector with Lepton Photon and Hadron Identification)

CERN Multimedia

Crawley, B; Munich, K; Mckay, R; Matorras, F; Joram, C; Malychev, V; Behrmann, A; Van dam, P; Drees, J K; Stocchi, A; Adam, W; Booth, P; Bilenki, M; Rosenberg, E I; Morton, G; Rames, J; Hahn, S; Cosme, G; Ventura, L; Marco, J; Tortosa martinez, P; Monge silvestri, R; Moreno, S; Phillips, H; Alekseev, G; Boudinov, E; Martinez rivero, C; Gitarskiy, L; Davenport, M; De clercq, C; Firestone, A; Myagkov, A; Belous, K; Haider, S; Hamilton, K M; Lamsa, J; Rahmani, M H; Malek, A; Hughes, G J; Peralta, L; Carroll, L; Fuster verdu, J A; Cossutti, F; Gorn, L; Yi, J I; Bertrand, D; Myatt, G; Richard, F; Shapkin, M; Hahn, F; Ferrer soria, A; Reinhardt, R; Renton, P; Sekulin, R; Timmermans, J; Baillon, P

2002-01-01

% DELPHI The DELPHI Detector (Detector with Lepton Photon and Hadron Identification) \\\\ \\\\DELPHI is a general purpose detector for physics at LEP on and above the Z$^0$, offering three-dimensional information on curvature and energy deposition with fine spatial granularity as well as identification of leptons and hadrons over most of the solid angle. A superconducting coil provides a 1.2~T solenoidal field of high uniformity. Tracking relies on the silicon vertex detector, the inner detector, the Time Projection Chamber (TPC), the outer detector and forward drift chambers. Electromagnetic showers are measured in the barrel with high granularity by the High Density Projection Chamber (HPC) and in the endcaps by $ 1 ^0 $~x~$ 1 ^0 $ projective towers composed of lead glass as active material and phototriode read-out. Hadron identification is provided mainly by liquid and gas Ring Imaging Counters (RICH). The instrumented magnet yoke serves for hadron calorimetry and as filter for muons, which are identified in t...

Estimating Outer Zone Radial Diffusion Coefficients from Drift Scale Fluctuations in Van Allen Particle Data

Science.gov (United States)

O'Brien, T. P., III; Claudepierre, S. G.

2017-12-01

During geomagnetic storms, the Earth's outer radiation belt experiences enhanced radial transport. This transport occurs via phase-dependent radial displacements of particles, either by impulsive events or drift resonant waves. Because transport is phase dependent, it produces drift phase bunching, which can be observed with in situ particle detectors. We provide bounds on the radial diffusion coefficients derived from this drift phase structure as seen by NASA's Van Allen Probes. We compare these bounds to published radial diffusion coefficient models, particularly those derived independently from electromagnetic field observations.

Switching a gas detector types misromegas

International Nuclear Information System (INIS)

Hafsi, Marwa; Gannouni, Sonia

2010-01-01

Micromegas is a gas enclosure made up of two stages separated by a micro grille: the first volume of gas, 2 cm is limited by cathode and the micro grille, is the space of conversion or of drift where are creating the primary electron-ion pairs. The second volume, 100 μ m limited by the micro grille and the plan of conduction (anode), is the space of amplification which with the function to amplify the electrons by phenomenon d' avalanche. The function of this type of detector rests on various physical parameters which come into play: speed of drift of the electrons in gas, space and temporal resolution, attachment The simulations allow studying these parameters to optimize the operation of the detector by choosing a good compromise, in particular with regard to the composition of gas. Two simulation programs used to understand certain physical phenomena (configuration of the field electric in the detector, properties of transport of the electrons in gas) are Garfield and Magboltz.

Real time track finding in a drift chamber with a VLSI neural network

International Nuclear Information System (INIS)

Lindsey, C.S.; Denby, B.; Haggerty, H.; Johns, K.

1992-01-01

In a test setup, a hardware neural network determined track parameters of charged particles traversing a drift chamber. Voltages proportional to the drift times in 6 cells of the 3-layer chamber were inputs to the Intel ETANN neural network chip which had been trained to give the slope and intercept of tracks. We compare network track parameters to those obtained from off-line track fits. To our knowledge this is the first on-line application of a VLSI neural network to a high energy physics detector. This test explored the potential of the chip and the practical problems of using it in a real world setting. We compare the chip performance to a neural network simulation on a conventional computer. We discuss possible applications of the chip in high energy physics detector triggers. (orig.)

Laboratory tests on neutron shields for gamma-ray detectors in space

CERN Document Server

Hong, J; Hailey, C J

2000-01-01

Shields capable of suppressing neutron-induced background in new classes of gamma-ray detectors such as CdZnTe are becoming important for a variety of reasons. These include a high cross section for neutron interactions in new classes of detector materials as well as the inefficient vetoing of neutron-induced background in conventional active shields. We have previously demonstrated through Monte-Carlo simulations how our new approach, supershields, is superior to the monolithic, bi-atomic neutron shields which have been developed in the past. We report here on the first prototype models for supershields based on boron and hydrogen. We verify the performance of these supershields through laboratory experiments. These experimental results, as well as measurements of conventional monolithic neutron shields, are shown to be consistent with Monte-Carlo simulations. We discuss the implications of this experiment for designs of supershields in general and their application to future hard X-ray/gamma-ray experiments...

A TPC-like readout method for high precision muon-tracking using GEM-detectors

Energy Technology Data Exchange (ETDEWEB)

Flierl, Bernhard; Biebel, Otmar; Bortfeldt, Jonathan; Hertenberger, Ralf; Klitzner, Felix; Loesel, Philipp; Mueller, Ralph [Ludwig-Maximilians-Universitaet Muenchen (Germany); Zibell, Andre [Julius-Maximilians-Universitaet Wuerzburg (Germany)

2016-07-01

Gaseous electron multiplier (GEM) detectors are well suited for tracking of charged particles. Three dimensional tracking in a single layer can be achieved by application of a time-projection-chamber like readout mode (μTPC), if the drift time of the electrons is measured and the position dependence of the arrival time is used to calculate the inclination angle of the track. To optimize the tracking capabilities for ion tracks drift gas mixtures with low drift velocity have been investigated by measuring tracks of cosmic muons in a compact setup of four GEM-detectors of 100 x 100 x 6 mm{sup 3} active volume each and an angular acceptance of -25 to 25 . The setup consists of three detectors with two-dimensional strip readout layers of 0.4 mm pitch and one detector with a single strip readout layer of 0.25 mm pitch. All strips are readout by APV25 frontend boards and the amplification stage in the detectors consists of three GEM-foils. Tracks are reconstructed by the μTPC-method in one of the detectors and are then compared to the prediction from the other three detectors defined by the center of charge in every detector. We report our study of Argon and Helium based noble gas mixtures with carbon-dioxide as quencher.

Consistent measurements comparing the drift features of noble gas mixtures

CERN Document Server

Becker, U; Fortunato, E M; Kirchner, J; Rosera, K; Uchida, Y

1999-01-01

We present a consistent set of measurements of electron drift velocities and Lorentz deflection angles for all noble gases with methane and ethane as quenchers in magnetic fields up to 0.8 T. Empirical descriptions are also presented. Details on the World Wide Web allow for guided design and optimization of future detectors.

Numerical Study of Thermal Stresses for the Semiconductor CdZnTe in Vertical Bridgman

OpenAIRE

Jamai , Hanen; El Ganaoui , M.; Sammouda , Habib; Pateyron , Bernard

2015-01-01

International audience; The aim of this work is to present a numerical simulation of thermal stress in directional solidification of CdZnTe in vertical Bridgman apparatus. Especial attention will be attributed to show the importance of cooling temperature and time's growth affecting the thermal stress. Furthermore, we will focus on investigating the thermal stress' components and their distribution in crystal, which gives a detailed about the stress distribution and consequently on the distri...

Measurement of the wire tension and position of the muon detector in the CMS project

International Nuclear Information System (INIS)

Niu Weiping

2004-01-01

The Large Hadron Collider (LHC) is currently being constructed at CERN including the ATLAS (A Toroidal LHC Apparatus) and CMS. It this report, it is have a sample introduction of CMS Muon detector, the drift tube introduction and chamber construction. The scope of this report covers the drift tube design and technical description; measurement of the wire tension of the Muon detector and the quality control; measurement of the wire position of the Muon detector and the quality control and so on. (authors)

Summary of activity. Topic I: detectors and experiments

International Nuclear Information System (INIS)

Marx, J.; Ozaki, S.

Results of a workshop studying detectors for Isabelle experimental halls are described. The detectors must be very reliable. Spatial resolution of the tracking detectors must be high to provide accurate measurements of angle and momentum, retain a short resolving time, and show excellent multiparticle handling capability. Included in the study were hodoscopes, drift chambers, proportional chambers, time projection chambers, Cherenkov counters, electromagnetic shower detectors, and hadron calorimeters. Data handling methods were also included in the studies

A New Approach for Evaluating Charge Transport Properties of Semiconductor Detectors

International Nuclear Information System (INIS)

Kim, Kyung O; Kim, Jong Kyung; Kim, Soon Young; Ha, Jang Ho

2009-01-01

The semiconductor detectors (e.g., CdTe, CdZnTe, and HgI 2 ) have been widely used for radiation detection and medical imaging because of its various outstanding features such as excellent energy resolution, wide bandgap energy, room temperature operation, and so on. Unfortunately, the performance of these detectors is mainly limited by the charge transport properties of semiconductor, especially the mobility-lifetime products (i.e., (μτ) e and ((μτ) h ). Hence, the analysis on the mobility-lifetime products is very important for evaluating correct characteristics of semiconductor detectors. A commonly used method to analyze the mobilitylifetime products is based on their responses to α particle. However, the α particle method cannot evaluate the ((μτ)h product in many cases, because a semiconductor detector operating at positive bias voltages often yields the energy spectrum without the peaks. This method is also known to be very sensitive to the experimental conditions as well as surface conditions of the detector. In this study, a new approach with gamma-ray instead of α particle was carried out to solve the determination difficulty of the ((μτ) h product with common method. The special relation between the two mobility-lifetime products, which we call the 'Nural equation', was also developed to simply obtain each parameter based on Hecht equation

Design and performance of a straw tube drift chamber

International Nuclear Information System (INIS)

Oh, S.H.; Wesson, D.K.; Cooke, J.; Goshaw, A.T.; Robertson, W.J.; Walker, W.D.

1991-01-01

The design and performance of the straw drift chambers used in E735 is reported. The chambers are constructed from 2.5 cm radius aluminized mylar straw tubes with wall thickness less than 0.2 mm. Also, presented are the results of tests with 2 mm radius straw tubes. The small tube has a direct detector application at the Superconducting Super Collider. (orig.)

Design and performance of a straw tube drift chamber

Science.gov (United States)

Oh, S. H.; Wesson, D. K.; Cooke, J.; Goshaw, A. T.; Robertson, W. J.; Walker, W. D.

1991-06-01

The design and performance of the straw drift chambers used in E735 is reported. The chambers are constructed from 2.5 cm radius aluminized mylar straw tubes with wall thickness less than 0.2 mm. Also, presented are the results of tests with 2 mm radius straw tubes. The small tube has a direct detector application at the Superconducting Super Collider.

Pulse height measurements and electron attachment in drift chambers operated with Xe,CO{sub 2} mixtures

Energy Technology Data Exchange (ETDEWEB)

Andronic, A. E-mail: a.andronic@gsi.de; Appelshaeuser, H.; Blume, C.; Braun-Munzinger, P.; Bucher, D.; Busch, O.; Ramirez, A.C.A. Castillo; Catanescu, V.; Ciobanu, M.; Daues, H.; Devismes, A.; Emschermann, D.; Fateev, O.; Garabatos, C.; Herrmann, N.; Ivanov, M.; Mahmoud, T.; Peitzmann, T.; Petracek, V.; Petrovici, M.; Reygers, K.; Sann, H.; Santo, R.; Schicker, R.; Sedykh, S.; Shimansky, S.; Simon, R.S.; Smykov, L.; Soltveit, H.K.; Stachel, J.; Stelzer, H.; Tsiledakis, G.; Vulpescu, B.; Wessels, J.P.; Windelband, B.; Winkelmann, O.; Xu, C.; Zaudtke, O.; Zanevsky, Yu.; Yurevich, V

2003-02-11

We present pulse height measurements in drift chambers operated with Xe,CO{sub 2} gas mixtures. We investigate the attachment of primary electrons on oxygen and SF{sub 6} contaminants in the detection gas. The measurements are compared with simulations of properties of drifting electrons. We present two methods to check the gas quality: gas chromatography and {sup 55}Fe pulse height measurements using monitor detectors.

Angular resolution of the gaseous micro-pixel detector Gossip

Science.gov (United States)

Bilevych, Y.; Blanco Carballo, V.; van Dijk, M.; Fransen, M.; van der Graaf, H.; Hartjes, F.; Hessey, N.; Koppert, W.; Nauta, S.; Rogers, M.; Romaniouk, A.; Veenhof, R.

2011-06-01

Gossip is a gaseous micro-pixel detector with a very thin drift gap intended for a high rate environment like at the pixel layers of ATLAS at the sLHC. The detector outputs not only the crossing point of a traversing MIP, but also the angle of the track, thus greatly simplifying track reconstruction. In this paper we describe a testbeam experiment to examine the angular resolution of the reconstructed track segments in Gossip. We used here the low diffusion gas mixture DME/CO 2 50/50. An angular resolution of 20 mrad for perpendicular tracks could be obtained from a 1.5 mm thin drift volume. However, for the prototype detector used at the testbeam experiment, the resolution of slanting tracks was worsened by poor time resolution of the pixel chip used.

Angular resolution of the gaseous micro-pixel detector Gossip

Energy Technology Data Exchange (ETDEWEB)

Bilevych, Y.; Blanco Carballo, V.; Dijk, M. van; Fransen, M.; Graaf, H. van der; Hartjes, F.; Hessey, N.; Koppert, W.; Nauta, S. [Nikhef, P.O. Box 41882, 1009 DB Amsterdam (Netherlands); Rogers, M. [Radboud University, P.O. Box 9102, 6500HC Nijmegen (Netherlands); Romaniouk, A.; Veenhof, R. [CERN, CH-1211, Geneve 23 (Switzerland)

2011-06-15

Gossip is a gaseous micro-pixel detector with a very thin drift gap intended for a high rate environment like at the pixel layers of ATLAS at the sLHC. The detector outputs not only the crossing point of a traversing MIP, but also the angle of the track, thus greatly simplifying track reconstruction. In this paper we describe a testbeam experiment to examine the angular resolution of the reconstructed track segments in Gossip. We used here the low diffusion gas mixture DME/CO{sub 2} 50/50. An angular resolution of 20 mrad for perpendicular tracks could be obtained from a 1.5 mm thin drift volume. However, for the prototype detector used at the testbeam experiment, the resolution of slanting tracks was worsened by poor time resolution of the pixel chip used.

Angular resolution of the gaseous micro-pixel detector Gossip

International Nuclear Information System (INIS)

Bilevych, Y.; Blanco Carballo, V.; Dijk, M. van; Fransen, M.; Graaf, H. van der; Hartjes, F.; Hessey, N.; Koppert, W.; Nauta, S.; Rogers, M.; Romaniouk, A.; Veenhof, R.

2011-01-01

Gossip is a gaseous micro-pixel detector with a very thin drift gap intended for a high rate environment like at the pixel layers of ATLAS at the sLHC. The detector outputs not only the crossing point of a traversing MIP, but also the angle of the track, thus greatly simplifying track reconstruction. In this paper we describe a testbeam experiment to examine the angular resolution of the reconstructed track segments in Gossip. We used here the low diffusion gas mixture DME/CO 2 50/50. An angular resolution of 20 mrad for perpendicular tracks could be obtained from a 1.5 mm thin drift volume. However, for the prototype detector used at the testbeam experiment, the resolution of slanting tracks was worsened by poor time resolution of the pixel chip used.

A Prototype Combination TPC Cherenkov Detector with GEM Readout for Tracking and Particle Identification and its Potential Use at an Electron Ion Collider

Directory of Open Access Journals (Sweden)

Woody Craig

2018-01-01

Full Text Available A prototype detector is being developed which combines the functions of a Time Projection Chamber for charged particle tracking and a Cherenkov detector for particle identification. The TPC consists of a 10×10×10 cm3 drift volume where the charge is drifted to a 10×10 cm2 triple GEM detector. The charge is measured on a readout plane consisting of 2×10 mm2 chevron pads which provide a spatial resolution ∼ 100 μm per point in the chevron direction along with dE/dx information. The Cherenkov portion of the detector consists of a second 10×10 cm2 triple GEM with a photosensitive CsI photocathode on the top layer. This detector measures Cherenkov light produced in the drift gas of the TPC by high velocity particles which are above threshold. CF4 or CF4 mixtures will be used as the drift gas which are highly transparent to UV light and can provide excellent efficiency for detecting Cherenkov photons. The drift gas is also used as the operating gas for both GEM detectors. The prototype detector has been constructed and is currently being tested in the lab with sources and cosmic rays, and additional tests are planned in the future to study the detector in a test beam.

A Prototype Combination TPC Cherenkov Detector with GEM Readout for Tracking and Particle Identification and its Potential Use at an Electron Ion Collider

Science.gov (United States)

Woody, Craig; Azmoun, Babak; Majka, Richard; Phipps, Michael; Purschke, Martin; Smirnov, Nikolai

2018-02-01

A prototype detector is being developed which combines the functions of a Time Projection Chamber for charged particle tracking and a Cherenkov detector for particle identification. The TPC consists of a 10×10×10 cm3 drift volume where the charge is drifted to a 10×10 cm2 triple GEM detector. The charge is measured on a readout plane consisting of 2×10 mm2 chevron pads which provide a spatial resolution ˜ 100 μm per point in the chevron direction along with dE/dx information. The Cherenkov portion of the detector consists of a second 10×10 cm2 triple GEM with a photosensitive CsI photocathode on the top layer. This detector measures Cherenkov light produced in the drift gas of the TPC by high velocity particles which are above threshold. CF4 or CF4 mixtures will be used as the drift gas which are highly transparent to UV light and can provide excellent efficiency for detecting Cherenkov photons. The drift gas is also used as the operating gas for both GEM detectors. The prototype detector has been constructed and is currently being tested in the lab with sources and cosmic rays, and additional tests are planned in the future to study the detector in a test beam.

The physics and technology of Si and Ge detectors

International Nuclear Information System (INIS)

Stab, Lucien

Semiconductor physics fundamentals are recalled (energy levels in crystalline solids, level population, charge carrier transport) as an introduction to studying NP junction at thermal equilibrium, or reversly biased. The fabrication of semiconductor detectors including surface barrier detectors, implanted junctions, and lithium-drifted semiconductors is discussed [fr

Status of the construction of the KLOE Drift Chamber

International Nuclear Information System (INIS)

Dell'Agnello, S.

1997-01-01

A status report on the construction of the drift chamber for the KLOE experiment at the LNF DAΦNE Φ-factory is given. Physics requirements, detector design performance and its key mechanical features and components are briefly reviewed. The program currently consists of (i) the preparation of final detector components, complemented by (ii) extensive tests of prototypes of critical mechanical parts (like the end plates) and the ''test construction'' of a 1:1 chamber prototype. These two sub-programs are pursued in parallel. Single-component prototype checks include surveys of their shape and size, of accuracy of wire-hole drilling, measurements of their displacement or buckling under nominal load. The ''test construction'' is the debugging of mechanical assembly, survey and alignment of mechanics and of wire-stringing robotics, the actual stringing of a sample 2000 holes drilled on the prototype end plates, the measurement of electrical properties of strung wires, as well as of their mechanical tension. These extensive tests have been successfully completed; they represent an effective hands-on training of the construction group, and will allow a prompt and steady start of the drift chamber wire stringing as all necessary components became available at LNF. (orig.)

Construction of a drift chamber prototype for the CMS experiment

International Nuclear Information System (INIS)

Berdugo, J.; Cerrada, M.; Daniel, M.; Martin, F.; Mocholi, J.; Romero, L.

1997-01-01

General design features of a small size drift chamber prototype are described in this report. Prototype construction has taken place at CIEMAT and we explain in detail the assembly procedure. This activity is part of a long term project to mass produce chambers for the muon barrel detector of the CMS experiment which will be installed at CERN. (Author)

Reducing Pesticide Drift

Science.gov (United States)

Provides information about pesticide spray drift, including problems associated with drift, managing risks from drift and the voluntary Drift Reduction Technology program that seeks to reduce spray drift through improved spray equipment design.

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-06-15

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

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

Science.gov (United States)

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

2017-06-01

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

Beam Aborts in PEP-II Rings and Lingering Drift Chamber Currents

International Nuclear Information System (INIS)

Meshkat, N.

2004-01-01

The BABAR detector at SLAC was designed to study CP-violation in B-meson decays from electron-positron collisions in the PEP-II electron-positron storage rings. Background radiation in the High Energy Ring (HER) and Low Energy Ring (LER) of PEP-II has the potential to damage the sensitive equipment in the BABAR detector. As a result, the beams in the HER and LER can be aborted to prevent such damage. In the span of a few microseconds, the HER and LER currents drop from, for example, 1450 micro Amps and 2300 micro Amps, respectively, to zero. At this time the voltage in the Drift Chamber is rapidly ramped down from a potential of 1930 V to a safe potential of 800 V, thus we would expect the currents in the Drift Chamber to quickly go to zero once the beams are aborted. However, we observe an average 15 second delay in the measured time it takes for all current in the Drift Chamber to fall below 1 micro Amp. This delay has been hypothesized as an instrumentation issue and not as a physical phenomenon. The specific sources of this error are still not completely known, but analysis suggests that it results from the interplay of the CAEN High Voltage supplies and the EPICS system and/or limitations within those systems

Detectors and signal processing for high-energy physics

International Nuclear Information System (INIS)

Rehak, P.

1981-01-01

Basic principles of the particle detection and signal processing for high-energy physics experiments are presented. It is shown that the optimum performance of a properly designed detector system is not limited by incidental imperfections, but solely by more fundamental limitations imposed by the quantum nature and statistical behavior of matter. The noise sources connected with the detection and signal processing are studied. The concepts of optimal filtering and optimal detector/amplifying device matching are introduced. Signal processing for a liquid argon calorimeter is analyzed in some detail. The position detection in gas counters is studied. Resolution in drift chambers for the drift coordinate measurement as well as the second coordinate measurement is discussed

The Mark II vertex detectors: Status and prospects

International Nuclear Information System (INIS)

Jaros, J.A.

1987-03-01

The art of detecting the decay vertices from heavy quarks and leptons is comparatively new at electron-positron storage rings. So far, drift chambers positioned just outside the vacuum pipes which surround the interfaction region have provided the first accurate determinations of the tau and bottom lifetimes, and confirmed earlier measurements of charmed particle lifetimes. ''Second generation'' vertex detectors have demonstrated the feasibility of tagging heavy flavors by observing decay vertices, and are being used to search for anomalous decay topologies. These chambers have modest resolution on the scale of the effects they seek to measure, but are now well-understood and reliable tools. A generation of vertex detectors, considerably more ambitious, is under construction for experiments at SLC and LEP. They boast impact parameter resolution improved by a factor of four or more over previous detectors, and sub-millimeter track-pair resolution. The Mark II collaboration hopes to reach these goals with a high pressure precision drift chamber, and eventually surpass them with the addition of a silicon microstrip detector

The Mark II vertex detectors: Status and prospects

Energy Technology Data Exchange (ETDEWEB)

Jaros, J.A.

1987-03-01

The art of detecting the decay vertices from heavy quarks and leptons is comparatively new at electron-positron storage rings. So far, drift chambers positioned just outside the vacuum pipes which surround the interfaction region have provided the first accurate determinations of the tau and bottom lifetimes, and confirmed earlier measurements of charmed particle lifetimes. ''Second generation'' vertex detectors have demonstrated the feasibility of tagging heavy flavors by observing decay vertices, and are being used to search for anomalous decay topologies. These chambers have modest resolution on the scale of the effects they seek to measure, but are now well-understood and reliable tools. A generation of vertex detectors, considerably more ambitious, is under construction for experiments at SLC and LEP. They boast impact parameter resolution improved by a factor of four or more over previous detectors, and sub-millimeter track-pair resolution. The Mark II collaboration hopes to reach these goals with a high pressure precision drift chamber, and eventually surpass them with the addition of a silicon microstrip detector.

Effects of bulk and surface conductivity on the performance of CdZnTe pixel detectors

DEFF Research Database (Denmark)

Bolotnikov, A.E.; Chen, C.M.H.; Cook, W.R.

2002-01-01

, the existence of a thin (10-100 A) oxide layer on the surface of CZT, formed during the fabrication process, affects both bulk and surface leakage currents. We demonstrate that the measured I-V dependencies of bulk current can be explained by considering the CZT detector as a metal-semiconductor-metal system......-collection efficiency in detectors with multicontact geometry; some fraction of the electric field lines that originated on the cathode intersects the surface areas between the pixel contacts where the charge produced by an ionizing particle gets trapped. To overcome this effect, we place a grid of thin electrodes...

Fabrication and utilization of semiconductor radiation detectors

International Nuclear Information System (INIS)

Lemos Junior, Orlando Ferreira

1969-01-01

This paper describes the assembly of the equipment for the fabrication of Ge-Li drifted detectors and the technique used in the preparation of a Planar detector of 7 cm 2 x 0,5 cm for the Laboratory of the Linear Accelerator at the University of Sao Paulo, as well as the utilization of a 22 cm 3 coaxial detector for the analysis of fission product gamma rays at the Instituto de Engenharia Nuclear, Rio de Janeiro, R J, Brazil. (author)

The Electron Drift Instrument on Cluster: overview of first results

Directory of Open Access Journals (Sweden)

G. Paschmann

Full Text Available EDI measures the drift velocity of artificially injected electron beams. From this drift velocity, the perpendicular electric field and the local magnetic field gradients can be deduced when employing different electron energies. The technique requires the injection of two electron beams at right angles to the magnetic field and the search for those directions within the plane that return the beams to their associated detectors after one or more gyrations. The drift velocity is then derived from the directions of the two beams and/or from the difference in their times-of-flight, measured via amplitude-modulation and coding of the emitted electron beams and correlation with the signal from the returning electrons. After careful adjustment of the control parameters, the beam recognition algorithms, and the onboard magnetometer calibrations during the commissioning phase, EDI is providing excellent data over a wide range of conditions. In this paper, we present first results in a variety of regions ranging from the polar cap, across the magnetopause, and well into the magnetosheath.

Key words. Electron drift velocity (electric fields; plasma convection; instruments and techniques

Fast Adapting Ensemble: A New Algorithm for Mining Data Streams with Concept Drift

Science.gov (United States)

Ortíz Díaz, Agustín; Ramos-Jiménez, Gonzalo; Frías Blanco, Isvani; Caballero Mota, Yailé; Morales-Bueno, Rafael

2015-01-01

The treatment of large data streams in the presence of concept drifts is one of the main challenges in the field of data mining, particularly when the algorithms have to deal with concepts that disappear and then reappear. This paper presents a new algorithm, called Fast Adapting Ensemble (FAE), which adapts very quickly to both abrupt and gradual concept drifts, and has been specifically designed to deal with recurring concepts. FAE processes the learning examples in blocks of the same size, but it does not have to wait for the batch to be complete in order to adapt its base classification mechanism. FAE incorporates a drift detector to improve the handling of abrupt concept drifts and stores a set of inactive classifiers that represent old concepts, which are activated very quickly when these concepts reappear. We compare our new algorithm with various well-known learning algorithms, taking into account, common benchmark datasets. The experiments show promising results from the proposed algorithm (regarding accuracy and runtime), handling different types of concept drifts. PMID:25879051

The Mark II detector for the SLC

International Nuclear Information System (INIS)

Abrams, G.; Baden, A.R.; Boyer, J.; Butler, F.; Drell, P.S.; Fay, J.; Gidal, G.; Goldhaber, G.; Haggerty, J.; Harr, R.; Hearty, C.; Herrup, D.; Holmgren, S.O.; Jaffre, M.; Juricic, I.; Kadyk, J.A.; Kral, J.F.; Levi, M.E.; Lynch, G.R.; Richman, J.D.; Rouse, F.R.; Schaad, M.W.; Schmidke, W.B.; Schumm, B.A.; Trilling, G.H.; Wood, D.R.; Akerlof, C.; Bonvicini, G.; Chapman, J.; Chmeissani, M.; Frey, R.; Gero, E.; Hong, S.J.; Koska, W.; Nitz, D.; Petradza, M.; Thun, R.; Tschirhart, R.; Veltman, H.; Alexander, J.P.; Ballam, J.; Barklow, T.; Bartelt, J.; De Boer, W.; Boyarski, A.; Braune, K.; Bulos, F.; Burke, D.L.; Cords, D.; Coupal, D.P.; Destaebler, H.C.; Dorfan, J.M.; Feldman, G.J.; Fernandes, D.; Field, R.C.; Fordham, C.; Fujino, D.; Gan, K.K.; Glanzman, T.; Grosse-Wiesmann, P.; Hanson, G.; Hayes, K.; Himel, T.; Hutchinson, D.; Innes, W.R.; Jacobsen, R.G.; Jaros, J.A.; Jung, C.K.; Karlen, D.; Klein, S.R.; Koetke, D.; Komamiya, M.; Kowalski, L.A.; Kozanecki, W.; Lankford, A.J.; Larsen, R.R.; Lueth, V.; Mattison, T.; Moffeit, K.C.; Mueller, L.; Munger, C.T.; Nash, J.; Ong, R.A.; O'Shaughnessy, K.F.; Perl, J.; Perl, M.L.; Perrier, F.; Petersen, A.; Pitthan, R.; Riles, K.; Swartz, M.; Taylor, R.E.; Van Kooten, R.; Voruganti, P.; Weigend, A.; Woods, M.; Wormser, G.; Wright, R.; Alvarez, M.; Calvino, F.; Fernandez, E.; Ford, W.T.; Hinshaw, D.A.; Rankin, P.; Smith, J.G.; Wagner, S.R.; Weber, P.; White, S.L.; Averill, D.; Blockus, D.; Brabson, B.; Brom, J.M.; Murray, W.N.; Ogren, H.; Rust, D.R.; Snyder, A.; Yurko, M.; Barish, B.C.; Hawkes, C.M.; Hoenk, M.; Kuhlen, M.; Li, Z.; McKenna, J.A.; Milliken, B.D.; Nelson, M.E.; Peck, C.; Porter, F.C.; Soderstrom, E.; Stroynowski, R.; Weinstein, A.J.; Weir, A.J.; Wicklund, E.; Wolf, R.C.; Wu, D.Y.; Barnett, B.A.; Boswell, C.; Dauncey, P.; Drewer, D.C.; Harral, B.; Hylen, J.; Matthews, J.A.J.; Stoker, D.P.; Vejcik, S.; Breakstone, A.; Cence, R.J.; Gong, X.; Harris, F.A.; Koide, A.; Parker, S.I.; Green, A.; Lawrence Berkeley Lab., CA; California Univ., Berkeley

1989-01-01

The Mark II detector has been upgraded in preparation for its role as the first detector to take data at the Stanford Linear Collider. The new detector components include the central drift chamber, the time-of-flight system, the coil, the endcap electromagnetic calorimeters and the beam energy and luminosity measuring devices. There have also been improvements in detector hermeticity. All of the major components were installed for a test run at the PEP storage ring (√s=29 GeV) in 1985. This paper describes the upgraded detector, including its trigger and data acquisition systems, and gives performance figures for its components. Future improvements are also discussed. (orig.)

Matrix-controlled morphology evolution of Te inclusions in CdZnTe single crystal

International Nuclear Information System (INIS)

He, Yihui; Jie, Wanqi; Xu, Yadong; Wang, Tao; Zha, Gangqiang; Yu, Pengfei; Zheng, Xin; Zhou, Yan; Liu, Hang

2012-01-01

The fine morphologies of microscale Te inclusions in CdZnTe single crystal were investigated to reveal their shape evolution. Such inclusions from crystal ingots with different post-growth cooling rates were analyzed using scanning electron microscopy after surface treatment. A tetrakaidecahedron model embodying {1 0 0} and {1 1 1} matrix facets was developed to interpret the form of the Te inclusions. An entire shape evolution process was also proposed where the final configuration of the Te inclusions was a tetrahedron comprising {1 1 1}B facets.

Characterization of the imaging performance of the simultaneously counting and integrating X-ray detector CIX

Energy Technology Data Exchange (ETDEWEB)

Fink, Johannes

2010-01-15

The CIX detector is a direct converting hybrid pixel detector designed for medical X-ray imaging applications. Its de ning feature is the simultaneous operation of a photon counter as well as an integrator in every pixel cell. This novel approach o ers a dynamic range of more than five orders of magnitude, as well as the ability to directly obtain the average photon energy from the measured data. Several CIX 0.2 ASICs have been successfully connected to CdTe, CdZnTe and Si sensors. These detector modules were tested with respect to the imaging performance of the simultaneously counting and integrating concept under X-ray irradiation. Apart from a characterization of the intrinsic benefits of the CIX concept, the sensor performance was also investigated. Here, the two parallel signal processing concepts offer valuable insights into material related effects like polarization and temporal response. The impact of interpixel coupling effects like charge-sharing, Compton scattering and X-ray fluorescence was evaluated through simulations and measurements. (orig.)

Characterization of the imaging performance of the simultaneously counting and integrating X-ray detector CIX

International Nuclear Information System (INIS)

Fink, Johannes

2010-01-01

The CIX detector is a direct converting hybrid pixel detector designed for medical X-ray imaging applications. Its de ning feature is the simultaneous operation of a photon counter as well as an integrator in every pixel cell. This novel approach o ers a dynamic range of more than five orders of magnitude, as well as the ability to directly obtain the average photon energy from the measured data. Several CIX 0.2 ASICs have been successfully connected to CdTe, CdZnTe and Si sensors. These detector modules were tested with respect to the imaging performance of the simultaneously counting and integrating concept under X-ray irradiation. Apart from a characterization of the intrinsic benefits of the CIX concept, the sensor performance was also investigated. Here, the two parallel signal processing concepts offer valuable insights into material related effects like polarization and temporal response. The impact of interpixel coupling effects like charge-sharing, Compton scattering and X-ray fluorescence was evaluated through simulations and measurements. (orig.)

CdZnTe quantum dots study: energy and phase relaxation process

International Nuclear Information System (INIS)

Viale, Yannick

2004-01-01

We present a study of the electron-hole pair energy and phase relaxation processes in a CdTe/ZnTe heterostructure, in which quantum dots are embedded. CdZnTe quantum wells with a high Zinc concentration, separated by ZnTe barriers, contain islands with a high cadmium concentration. In photoluminescence excitation spectroscopy experiments, we evidence two types of electron hole pair relaxation processes. After being excited in the CdZnTe quantum well, the pairs relax their energy by emitting a cascade of longitudinal optical phonons until they are trapped in the quantum dots. Before their radiative recombination follows an intra-dot relaxation, which is attributed to a lattice polarization mechanism of the quantum dots. It is related to the coupling between the electronic and the vibrational states. Both relaxation mechanisms are reinforced by the strong polar character of the chemical bond in II-VI compounds. Time resolved measurements of transmission variations in a pump-probe configuration allowed us to investigate the population dynamics of the electron-hole pairs during the relaxation process. We observe a relaxation time of about 2 ps for the longitudinal phonon emission cascade in the quantum well before a saturation of the quantum dot transition. We also measured an intra-box relaxation time of 25 ps. The comparison of various cascades allows us to estimate the emission time of a longitudinal optical phonon in the quantum well to be about 100 fs. In four waves mixing experiments, we observe oscillations that we attribute to quantum beats between excitonic and bi-excitonic transitions. The dephasing times that we measure as function of the density of photons shows that excitons are strongly localized in the quantum dots. The excitonic dephasing time is much shorter than the radiative lifetime and is thus controlled by the intra-dot relaxation time. (author) [fr

Large volume cryogenic silicon detectors

International Nuclear Information System (INIS)

Braggio, C.; Boscardin, M.; Bressi, G.; Carugno, G.; Corti, D.; Galeazzi, G.; Zorzi, N.

2009-01-01

We present preliminary measurements for the development of a large volume silicon detector to detect low energy and low rate energy depositions. The tested detector is a one cm-thick silicon PIN diode with an active volume of 31 cm 3 , cooled to the liquid helium temperature to obtain depletion from thermally-generated free carriers. A thorough study has been done to show that effects of charge trapping during drift disappears at a bias field value of the order of 100V/cm.

The effect of cathode bias (field effect) on the surface leakage current of CdZnTe detectors

DEFF Research Database (Denmark)

Bolotnikov, A.E.; Chen, C.M.H.; Cook, W.R.

2003-01-01

Surface resistivity is an important parameter of multi-electrode CZT detectors such as coplanar-grid, strip, or pixel detectors. Low surface resistivity results in a high leakage current and affects the charge collection efficiency in the areas near contacts. Thus, it is always desirable to have ...

The Use of 3D Printing in the Development of Gaseous Radiation Detectors

Science.gov (United States)

Fargher, Sam; Steer, Chris; Thompson, Lee

2018-01-01

Fused Deposition Modelling has been used to produce a small, single wire, Iarocci-style drift tube to demonstrate the feasibility of using the Additive Manufacturing technique to produce cheap detectors, quickly. Recent technological developments have extended the scope of Additive Manufacturing, or 3D printing, to the possibility of fabricating Gaseous Radiation Detectors, such as Single Wire Proportional Counters and Time Projection Chambers. 3D printing could allow for the production of customisable, modular detectors; that can be easily created and replaced and the possibility of printing detectors on-site in remote locations and even for outreach within schools. The 3D printed drift tube was printed using Polylactic acid to produce a gas volume in the shape of an inverted triangular prism; base length of 28 mm, height 24.25 mm and tube length 145 mm. A stainless steel anode wire was placed in the centre of the tube, mid-print. P5 gas (95% Argon, 5% Methane) was used as the drift gas and a circuit was built to capacitively decouple signals from the high voltage. The signal rate and average pulse height of cosmic ray muons were measured over a range of bias voltages to characterise and prove correct operation of the printed detector.

Effective ionization coefficients, electron drift velocities, and limiting breakdown fields for gas mixtures of possible interest to particle detectors

International Nuclear Information System (INIS)

Datskos, P.G.

1991-01-01

We have measured the gas-density, N, normalized effective ionization coefficient, bar a/N, and the electron drift velocity, w, as a function of the density-reduced electric field, E/N, and obtained the limiting, (E/N) lim , value of E/N for the unitary gases Ar, CO 2 , and CF 4 , the binary gas mixtures CO 2 :Ar (20: 80), CO 2 :CH 4 (20:80), and CF 4 :Ar (20:80), and the ternary gas mixtures CO 2 :CF 4 :Ar (10:10:80) and H 2 O: CF 4 :Ar (2:18:80). Addition of the strongly electron thermalizing gas CO 2 or H 2 O to the binary mixture CF 4 :Ar (1)''cools'' the mixture (i.e., lowers the electron energies), (2) has only a small effect on the magnitude of w(E/N) in the E/N range employed in the particle detectors, and (3) increases bar a/N for E/N ≥ 50 x 10 -17 V cm 2 . The increase in bar a/N, even though the electron energies are lower in the ternary mixture, is due to the Penning ionization of CO 2 (or H 2 O) in collisions with excited Ar* atoms. The ternary mixtures -- being fast, cool, and efficient -- have potential for advanced gas-filled particle detectors such as those for the SCC muon chambers. 17 refs., 8 figs., 1 tab

Elsevier R&D on a new type of micropattern gaseous detector: The Fast Timing Micropattern detector

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