Computational Models for Crystal Growth of Radiation Detector Materials: Growth of CZT by the EDG Method

AbstractCrystals are the central materials element of most gamma radiation detection systems, yet there remains surprisingly little fundamental understanding about how these crystals grow, how growth conditions affect crystal properties, and, ultimately, how detector performance is affected. Without this understanding, the prospect for significant materials improvement, i.e., growing larger crystals with superior quality and at a lower cost, remains a difficult and expensive exercise involving exhaustive trial-and-error experimentation in the laboratory. Thus, the overall goal of this research is to develop and apply computational modeling to better understand the processes used to grow bulk crystals employed in radiation detectors. Specifically, the work discussed here aims at understanding the growth of cadmium zinc telluride (CZT), a material of long interest to the detector community. We consider the growth of CZT via gradient freeze processes in electrodynamic multizone furnaces and show how crucible mounting and design are predicted to affect conditions for crystal growth.

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Radiation detector materials: An overview

Journal of Materials Research ◽

10.1557/jmr.2008.0319 ◽

2008 ◽

Vol 23 (10) ◽

pp. 2561-2581 ◽

Cited By ~ 151

Author(s):

B.D. Milbrath ◽

A.J. Peurrung ◽

M. Bliss ◽

W.J. Weber

Keyword(s):

Homeland Security ◽

Performance Metrics ◽

Materials Science ◽

Radiation Detector ◽

Radiation Detection ◽

National Defense ◽

Challenges And Opportunities ◽

Science Community ◽

Faster Development ◽

Detector Materials

Due to events of the past two decades, there has been new and increased usage of radiation-detection technologies for applications in homeland security, nonproliferation, and national defense. As a result, there has been renewed realization of the materials limitations of these technologies and greater demand for the development of next-generation radiation-detection materials. This review describes the current state of radiation-detection material science, with particular emphasis on national security needs and the goal of identifying the challenges and opportunities that this area represents for the materials-science community. Radiation-detector materials physics is reviewed, which sets the stage for performance metrics that determine the relative merit of existing and new materials. Semiconductors and scintillators represent the two primary classes of radiation detector materials that are of interest. The state-of-the-art and limitations for each of these materials classes are presented, along with possible avenues of research. Novel materials that could overcome the need for single crystals will also be discussed. Finally, new methods of material discovery and development are put forward, the goal being to provide more predictive guidance and faster screening of candidate materials and thus, ultimately, the faster development of superior radiation-detection materials.

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Enhancement of Mercuric Iodide Detector Performance Through Crystal Growth in Microgravity: the Roles of Lattice Order

MRS Proceedings ◽

10.1557/proc-487-345 ◽

1997 ◽

Vol 487 ◽

Cited By ~ 1

Author(s):

Bruce Steiner ◽

Lodewijk Van Den Berg ◽

Uri Laor

Keyword(s):

Crystal Growth ◽

Crystal Lattice ◽

Hole Mobility ◽

Radiation Detectors ◽

High Energy ◽

Structural Features ◽

Mercuric Iodide ◽

Detector Performance ◽

Lattice Order ◽

Extraneous Material

AbstractThe hole-mobility•carrier-lifetime product of α mercuric iodide high energy radiation detectors has been enhanced through vapor crystal growth in microgravity. This improvement is closely correlated with specific characteristics of the crystal lattice, which have been identified by high resolution synchrotron x-ray diffraction imaging. These structural features and the associated performance are now being approached in terrestrial growth of α mercuric iodide.Gravity may affect the uniformity of this crystal lattice in two distinct ways: 1) directly through deformation that it imposes on the lattice during growth and 2) indirectly through convection, which mixes any extraneous material. Inclusions associated with these processes harden the lattice and facilitate lattice folding. These changes affect the electronic parameters of detectors made from the crystals. As purification procedures are optimized, the incorporation of extraneous material is curtailed, enhancing electronic properties in spite of lattice flexing through loss of precipitation hardening.These studies provide insight into the contribution of various aspects of crystalline order in α-mercuric iodide crystals to property improvement. This knowledge has led to modification of requirements for starting materials, adjustment of physical vapor growth procedures, and change in crystal handling procedures. As a result, the electronic performance of terrestrially grown radiation detectors has been improved, and we provide evidence that further enhancement is still possible.

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Purification of HgI2 Crystals from Physical Vapor Transport for Application as Radiation Detectors

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.586.156 ◽

2012 ◽

Vol 586 ◽

pp. 156-160 ◽

Cited By ~ 1

Author(s):

João F. Trencher Martins ◽

Robinson A. dos Santos ◽

Fabio E. da Costa ◽

Carlos H. de Mesquita ◽

Margarida M. Hamada

Keyword(s):

Impurity Concentration ◽

Radiation Detector ◽

Radiation Detectors ◽

Vapor Transport ◽

Future Application ◽

Physical Vapor Transport ◽

Semiconductor Detectors ◽

Trace Impurities ◽

Detector Performance ◽

Temperature Radiation

The establishment of a technique for mercury iodide (HgI2) purification and crystal growth is described, aiming this crystal future application as room temperature radiation semiconductor detectors. Repeated Physical Vapor Transport (PVT) technique was studied for purification and growth of the crystal. To evaluate the purification efficiency, measurements of the impurity concentration were made after each growth, analyzing the trace impurities. A significant decrease of the impurity concentration, resulting from the purification number, was observed. A significant improvement in the HgI2 radiation detector performance was achieved for purer crystals, growing the crystal twice by the PVT technique.

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Design of 4π Directional Radiation Detector based on Compton Scattering Effect

EPJ Web of Conferences ◽

10.1051/epjconf/202125307003 ◽

2021 ◽

Vol 253 ◽

pp. 07003

Author(s):

Ghelman Max ◽

Kopeika Natan ◽

Rotman Stenley ◽

Edvabsky Tal ◽

Vax Eran ◽

...

Keyword(s):

Radiation Detector ◽

Radiation Detection ◽

Radiation Detectors ◽

High Energy ◽

Field Of View ◽

Silicon Photomultiplier ◽

Space Applications ◽

Additional Advantage ◽

Directional Information ◽

Directional Radiation

Obtaining directional information is required in many applications such as nuclear homeland security, contamination mapping after a nuclear incident and radiological events, or during the decontamination work. However, many directional radiation detectors are based on directional shielding, made of lead or tungsten collimators, introducing two main drawbacks. The first is the size and weight, making those detectors too heavy and irrelevant for utilization in handheld devices, drone mapping, or space applications. The second drawback is the limited field of view, which requires multiple detectors to cover the whole required field of view or machinery to rotate the narrow field of view detector. We propose a novel 4π directional detector based on a segmented hollow cubic detector, which uses the Compton effect interactions with no heavy collimators. The symmetrical cubical design provides both higher efficiency and 4π detection ability. Instead of traditional two types of detectors (scatterer and absorber) structure, we use the same type of detector, based on GAGG(Ce) scintillator coupled to silicon photomultiplier. Additional advantage of the proposed detector obtained by locating the photon sensors inside the detector, behind the scintillators, which improves the radiation hardness required for space applications. Furthermore, such arrangement flattens the temperature variation across the detector, providing better gain stability. The main advantage of the proposed detector is the ability of 4pi radiation detection for high energy gamma-rays without the use of heavy collimators.

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Highly Manufacturable and Reliable CZT Detectors

Volume 1: Advanced Packaging; Emerging Technologies; Modeling and Simulation; Multi-Physics Based Reliability; MEMS and NEMS; Materials and Processes ◽

10.1115/ipack2013-73314 ◽

2013 ◽

Author(s):

Bill Burdick ◽

Jeff Erlbaum ◽

Kaustubh Nagarkar ◽

Brian Yanoff ◽

Liang Yin ◽

...

Keyword(s):

System Design ◽

Flip Chip ◽

Process Development ◽

Radiation Detector ◽

Element Model ◽

Radiation Detectors ◽

Healthcare Applications ◽

Detector Performance ◽

Test Standards ◽

Semiconductor Packages

Cadmium Zinc Telluride (CZT) based radiation detectors have been developed over the past decade and are, increasingly, being used in security and healthcare applications. Improvements in radiation detector performance, size, and cost have been achieved; however, the manufacturability and reliability of the individual CZT detector package continues to limit widespread use and new applications. To date, most CZT detector packages are designed, manufactured, and tested to requirements defined by manufacturers, rather than military, commercial, or industry standards, as is common for semiconductor packages. The lack of test standards has led to use restrictions and/or complex detector system design, as required to mitigate unknown or low detector package reliability. CZT detector packaging, as was the case for semiconductor packaging, has reached the point in technology maturation where a focus on optimizing detector design for manufacturability and reliability is appropriate and necessary. This paper reviews the systematic approach, including design, process development, and testing, utilized in the development and demonstration of a highly manufacturable and reliable (95% reliability at 1000 cycles) CZT detector package. Finite Element Model (FEM) based design and material trade-off studies, development of highly manufacturable and reliable commercial electronic assembly processes, failure mode identification and mitigation, selection and use of reliability test standards, and analyses are detailed for a flip-chip-CZT-on-ceramic substrate, detector package targeted for field deployment. As well, the next steps in package and system design, manufacturing, and reliability testing are proposed.

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Modeling the Crystal Growth of Cadmium Zinc Telluride: Accomplishments and Future Challenges

MRS Proceedings ◽

10.1557/proc-1164-l05-02 ◽

2009 ◽

Vol 1164 ◽

Cited By ~ 3

Author(s):

Jeffrey Derby ◽

David Gasperino ◽

Nan Zhang ◽

Andrew Yeckel

Keyword(s):

Crystal Growth ◽

Pacific Northwest ◽

Cadmium Zinc Telluride ◽

Central Element ◽

Zinc Telluride ◽

Radiation Detectors ◽

Growth Conditions ◽

Washington State University ◽

Improved Performance ◽

Cadmium Zinc

AbstractThe availability of large, single crystals of cadmium zinc telluride (CZT) with uniform properties would lead to improved performance of gamma radiation detectors fabricated from them. However, even though CZT crystals are the central element of these systems, there remains relatively little fundamental understanding about how these crystals grow and, especially, how crystal growth conditions affect the properties of grown crystals. This paper discusses the many challenges of growing better CZT crystals and how modeling may favorably impact these challenges. Our thesis is that crystal growth modeling is a powerful tool to complement experiments and characterization. It provides an important approach to close the loop between materials discovery, device research, systems performance, and producibility. Specifically, we discuss our efforts to model gradient freeze furnaces used to grow large CZT crystals at Pacific Northwest National Laboratories and Washington State University. Model results are compared with experimental measurements, and the insight gained from modeling is discussed.

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Photothermal, Photoelectric, and Photothermoelectric Effects in Bi-Sb Thin Films in the Terahertz Frequency Range at Room Temperature

Photonics ◽

10.3390/photonics8030076 ◽

2021 ◽

Vol 8 (3) ◽

pp. 76

Author(s):

Mikhail K. Khodzitsky ◽

Petr S. Demchenko ◽

Dmitry V. Zykov ◽

Anton D. Zaitsev ◽

Elena S. Makarova ◽

...

Keyword(s):

Thin Films ◽

Terahertz Radiation ◽

Room Temperature ◽

Voltage Drop ◽

Radiation Detection ◽

Radiation Detectors ◽

Thz Radiation ◽

Terahertz Frequency ◽

Frequency Range ◽

Terahertz Frequency Range

The terahertz frequency range is promising for solving various practically important problems. However, for the terahertz technology development, there is still a problem with the lack of affordable and effective terahertz devices. One of the main tasks is to search for new materials with high sensitivity to terahertz radiation at room temperature. Bi1−xSbx thin films with various Sb concentrations seem to be suitable for such conditions. In this paper, the terahertz radiation influence onto the properties of thermoelectric Bi1−xSbx 200 nm films was investigated for the first time. The films were obtained by means of thermal evaporation in vacuum. They were affected by terahertz radiation at the frequency of 0.14 terahertz (THz) in the presence of thermal gradient, electric field or without these influences. The temporal dependencies of photoconductivity, temperature difference and voltage drop were measured. The obtained data demonstrate the possibility for practical use of Bi1−xSbx thin films for THz radiation detection. The results of our work promote the usage of these thermoelectric materials, as well as THz radiation detectors based on them, in various areas of modern THz photonics.

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