scholarly journals Quaternary Semiconductor Cd1-xZnxTe1-ySey for High-Resolution, Room-Temperature Gamma-Ray Detection

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 827
Author(s):  
Sandeep K. Chaudhuri ◽  
Joshua W. Kleppinger ◽  
OmerFaruk Karadavut ◽  
Ritwik Nag ◽  
Krishna C. Mandal
Keyword(s):  
Crystal Growth ◽  
High Resolution ◽  
Charge Transport ◽  
Single Crystals ◽  
Homeland Security ◽  
Room Temperature ◽  
Gamma Ray ◽  
Radiation Detector ◽  
Growth Yield ◽  
Charge Trapping

The application of Cd0.9Zn0.1Te (CZT) single crystals, the primary choice for high-resolution, room-temperature compact gamma-ray detectors in the field of medical imaging and homeland security for the past three decades, is limited by the high cost of production and maintenance due to low detector grade crystal growth yield. The recent advent of its quaternary successor, Cd0.9Zn0.1Te1-ySey (CZTS), has exhibited remarkable crystal growth yield above 90% compared to that of ~33% for CZT. The inclusion of Se in appropriate stoichiometry in the CZT matrix is responsible for reducing the concentration of sub-grain boundary (SGB) networks which greatly enhances the compositional homogeneity and growth yield. SGB networks also host defect centers responsible for charge trapping, hence their reduced concentration ensures minimized charge trapping. Indeed, CZTS single crystals have shown remarkable improvement in electron charge transport properties and energy resolution over CZT detectors. However, our studies have found that the overall charge transport in CZTS is still limited by the hole trapping. In this article, we systematically review the advances in the CZTS growth techniques, its performance as room-temperature radiation detector, and the role of defects and their passivation studies needed to improve the performance of CZTS detectors further.

Alkali Metal Chalcogenides for Radiation Detection

2011 ◽  
Vol 1341 ◽  
Author(s):  
J. A. Peters ◽  
Zhifu Liu ◽  
B. W. Wessels ◽  
I. Androulakis ◽  
C. P. Sebastian ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Alkali Metal ◽  
Charge Transport ◽  
Band Gap ◽  
Room Temperature ◽  
Gamma Ray ◽  
Radiation Detector ◽  
Radiation Detection ◽  
Charge Carriers ◽  
Metal Chalcogenides

ABSTRACTWe report on the optical and charge transport properties of novel alkali metal chalcogenides, Cs2Hg6S7 and Cs2Cd3Te4, pertaining to their use in radiation detection. Optical absorption, photoconductivity, and gamma ray response measurements for undoped crystals were measured. The band gap energies of the Cs2Hg6S7 and Cs2Cd3Te4 compounds are 1.63 eV and 2.45 eV, respectively. The mobility-lifetime products for charge carriers are of the order of ~10-3 cm2/V for electrons and ~10-4 cm2/V for holes. Detectors fabricated from the ternary compound Cs2Hg6S7 shows well-resolved spectroscopic features at room temperature in response to ϒ -rays at 122 keV from a 57Co source, indicating its potential as a radiation detector.

scholarly journals Recent developments in high-resolution-gamma-ray cargo-inspection technology

2018 ◽  
Vol 48 ◽  
pp. 1860109
Author(s):  
David Taylor ◽  
Victor Orphan ◽  
Eric Ackermann ◽  
Rhett Barnes ◽  
Ryan Shyffer ◽  
...  
Keyword(s):  
Signal Processing ◽  
High Resolution ◽  
Homeland Security ◽  
Gamma Ray ◽  
Imaging System ◽  
Digital Signal ◽  
Department Of Homeland Security ◽  
Legacy System ◽  
Cargo Inspection ◽  
Signal Processing Electronics

Under US Department of Homeland Security sponsorship, Spectral Labs Incorporated has developed a prototype high-resolution retrofit for an existing mobile VACIS, named the High-Resolution Imaging System (HiRIS). The legacy 256 NaI detectors in the VACIS detector column were replaced with 576 CsI detectors, more than doubling the pixel count. Using SiPMs to replace conventional PMTs allowed the packing of more detectors in the same VACIS detector enclosure. Legacy analog signal-processing electronics were replaced with advanced digital signal-processing electronics. Replacing gross counting in the legacy system with multichannel analysis of the counts from each detector will allow better control of detector crosstalk. The HiRIS detector modules were installed on a VACIS truck refurbished to as-new condition. Initial testing of the HiRIS prototype demonstrates enhanced spatial resolution by a factor of two as compared to the legacy system, without any degradation in throughput capability (20 containers per hour).

Crystal Growth and Ferroelectric Properties of Superlattice-Structured Bi4Ti3O12-PbBi4Ti4O15 Single Crystals

2008 ◽  
Vol 388 ◽  
pp. 237-240
Author(s):  
Mariko Ikezaki ◽  
Yuji Noguchi ◽  
Keiichi Katayama ◽  
Masaru Miyayama
Keyword(s):  
Crystal Growth ◽  
Single Crystals ◽  
Leakage Current ◽  
Room Temperature ◽  
Remanent Polarization ◽  
Marked Decrease ◽  
Ferroelectric Properties ◽  
Electron Hole ◽  
N2 Atmosphere ◽  
Saturated Polarization

Superlattice-structured Bi4Ti3O12- PbBi4Ti4O15 single crystals were grown, and their properties of polarization hysteresis and leakage current along the a axis were investigated. Oxidation annealing led to a marked increase in leakage current, while annealing in N2 atmosphere yielded a marked decrease in leakage current at room temperature. These results show that electron hole is the dominant carrier for the leakage current. A well-saturated polarization hysteresis with a remanent polarization of 41 μC/cm2 was observed, which is suggested to originate from the peculiar ferroelectric displacement of Bi in the Bi2O2 layers.

Recent advances in the development of high-resolution 3D cadmium–zinc–telluride drift strip detectors

2020 ◽  
Vol 27 (6) ◽  
pp. 1564-1576
Author(s):  
Leonardo Abbene ◽  
Gaetano Gerardi ◽  
Fabio Principato ◽  
Antonino Buttacavoli ◽  
Saverio Altieri ◽  
...  
Keyword(s):  
High Resolution ◽  
Room Temperature ◽  
Gamma Ray ◽  
Cadmium Zinc Telluride ◽  
Zinc Telluride ◽  
Strip Detectors ◽  
Correction Technique ◽  
Wide Range ◽  
Induced Charge ◽  
Cadmium Zinc

In the last two decades, great efforts have been made in the development of 3D cadmium–zinc–telluride (CZT) detectors operating at room temperature for gamma-ray spectroscopic imaging. This work presents the spectroscopic performance of new high-resolution CZT drift strip detectors, recently developed at IMEM-CNR of Parma (Italy) in collaboration with due2lab (Italy). The detectors (19.4 mm × 19.4 mm × 6 mm) are organized into collecting anode strips (pitch of 1.6 mm) and drift strips (pitch of 0.4 mm) which are negatively biased to optimize electron charge collection. The cathode is divided into strips orthogonal to the anode strips with a pitch of 2 mm. Dedicated pulse processing analysis was performed on a wide range of collected and induced charge pulse shapes using custom 32-channel digital readout electronics. Excellent room-temperature energy resolution (1.3% FWHM at 662 keV) was achieved using the detectors without any spectral corrections. Further improvements (0.8% FWHM at 662 keV) were also obtained through a novel correction technique based on the analysis of collected-induced charge pulses from anode and drift strips. These activities are in the framework of two Italian research projects on the development of spectroscopic gamma-ray imagers (10–1000 keV) for astrophysical and medical applications.

Defect Engineering of BiI3 Single Crystals: Enhanced Electrical and Radiation Performance for Room Temperature Gamma-Ray Detection

2014 ◽  
Vol 118 (6) ◽  
pp. 3244-3250 ◽  
Author(s):  
HyukSu Han ◽  
Minki Hong ◽  
Sasmit S. Gokhale ◽  
Susan B. Sinnott ◽  
Kelly Jordan ◽  
...  
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Gamma Ray ◽  
Defect Engineering

Interaction of 6H-Type Stacking Faults with Threading Screw Dislocations in PVT-Grown 4H-SiC Single Crystals

2012 ◽  
Vol 717-720 ◽  
pp. 411-414
Author(s):  
Shinya Sato ◽  
T. Fujimoto ◽  
H. Tsuge ◽  
M. Katsuno ◽  
W. Ohashi
Keyword(s):  
High Resolution ◽  
Single Crystals ◽  
Room Temperature ◽  
Stacking Faults ◽  
Screw Dislocations ◽  
X Ray

6H-type stacking faults (SFs) observed in PVT-grown 4H-SiC ingle crystals were investigated using Photoluminescence (PL) microscopy at room temperature. Structural analyses using high resolution X-ray topography have revealed that there exist no (n=4, 8) component in Burger’s vectors of the 6H-type SFs we observed, strongly suggesting that the 6H-type SFs are constructed either by insertions of very thin 6H-type foreign polytype inclusions or by successive repetitions of Shockley-type in-plane glides.

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