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Detection Technology
Published in Rick Houghton, William Bennett, Emergency Characterization of Unknown Materials, 2020
Rick Houghton, William Bennett
CZT crystal is an alloy of cadmium, zinc, and telluride that can be used in radiation detectors. Gamma radiation striking a CZT semiconductor array will generate electrons that can be detected. Certain manufacturing techniques are necessary to maximize electron detection. Uniform detector arrays with good resolution can be achieved by certain crystal doping methods and semiconductor construction. CZT radiation detectors can be formed into required shapes for certain applications and are sometimes chosen to detect gamma radiation within a specific range.
Semiconductor Sensors for XRD Imaging
Published in Joel Greenberg, Krzysztof Iniewski, X-Ray Diffraction Imaging, 2018
Krzysztof Iniewski, Adam Grosser
Modern baggage scanning equipment uses more efficient, direct method of radiation detection, as shown in Figure 2.9. The two-step process involving scintillator and photodiode is replaced by a semiconductor detector that converts X-rays directly into electric charge. High-purity Germanium (HPGe) is currently used in commercial systems, but CdTe and CZT sensors have recently attracted attention. CZT detectors in particular fit perfectly into these applications due their high stopping power, reasonable cost, high stability and reliability.
Application Specific Integrated Circuits for Direct X-Ray and Gamma-Ray Conversion in Security Applications
Published in Choi Jung Han, Iniewski Krzysztof, High-Speed and Lower Power Technologies, 2018
Krzysztof Iniewski, Chris Siu, Adam Grosser
Discovery of the compound semiconductors cadmium telluride (CdTe) and cadmium zinc telluride (CZT) as direct detectors has helped greatly to lower the cost, as both materials can operate efficiently at room temperature. The direct detection process, used by Ge, CdTe and CZT sensors, offers better efficiency and resolution compared to the traditional method using scintillators described earlier.
Investigation and Analysis of Thermoelectrically Cooled CZT Performance
Published in Nuclear Technology, 2023
Amanda D. E. Foley, Swomitra K. Mohanty, Glenn E. Sjoden
Cadmium zinc telluride (CZT) gamma spectrometers have been explored as a room temperature alternative to high-purity germanium gamma spectrometers due to their reasonable bandgap, 1.57 eV, and resolution, 5.4 keV at 59 keV, and the high atomic numbers of the individual elements.1–4 An area of study still under exploration is the overall impact of environmental changes on the performance of CZT detectors. A room temperature detector does not require forced cooling or temperature management, which leaves the detector prone to fluctuations in environmental temperature. Multiple parameters can affect the overall detector response as temperature changes, such as leakage current, bandgap, and thermal expansion. In addition, the electronic components affect the overall detector response if the off-the-shelf electrons are not individually characterized. The overall detector response is measured for this work, and the individual parameters that make up that response will be explored in future work. CZT has also been explored for nuclear nonproliferation objectives and unmanned aerial vehicle radiation mapping with widely variable ambient temperatures.5,6 For these reasons, the study of temperature change impacts on CZT performance is highly relevant.
Effect of 100 MeV Ni ion irradiation on CdZnTe thin films
Published in Radiation Effects and Defects in Solids, 2021
Praveen Dhangada, Madhavi Thakurdesai, Smita Survase, Vrunda Thakurdesai, L. Ajith DeSilva
Cadmium Zinc Telluride (CZT) is an important ternary II–VI compound semiconductor from chalcogenide class of materials. CZT has wide applications in opto-electronic devices and detectors (1). CZT possesses several interesting material properties like large absorption coefficient, high resistivity, high average atomic number and large bandgap (2). Another advantage of CZT thin films is that it has direct bandgap which can be continuously varied between 1.5 eV and 2.25 eV by changing the film composition (3, 4).
Non-invasive imaging techniques to assess myocardial perfusion
Published in Expert Review of Medical Devices, 2020
Olivier Villemain, Jérôme Baranger, Zakaria Jalal, Christopher Lam, Jérémie Calais, Mathieu Pernot, Barbara Cifra, Mark K. Friedberg, Luc Mertens
PET has a superior image quality and spatial resolution than SPECT (typically 4–7 mm and 12–15 mm, respectively). Regarding the temporal resolution, PET is also higher which allows for more accurate quantification of perfusion. PET is an established tool to provide clinically relevant quantitative levels of myocardial perfusion and CFR alongside qualitative myocardial perfusion images [21,22]. The acquisition could also be done both rest and stress images within a single scanning session due to the short physical half-life of the PET perfusion tracers. However, the main limitation to use of PET is with the current MPI PET tracers there need for an onsite cyclotron or generator. In contrast, MPI SPECT tracers (201Tl, 99mTc) are widely available. Therefore, although PET has theoretical advantages over SPECT, the clinical effect of this difference may be small [23]. The detector used for MPI is another important consideration. Cadmium-zinc-telluride (CZT) semi-conductor detectors for SPECT imaging have superior energy and spatial resolution [24]. These SPECT cameras are more sensitive and therefore require shorter imaging times, at lower radioactivity administration. The CZT camera provides very fast MPI and allows the acquisition of serial dynamic images. Hybrid imaging cameras provide a fusion of anatomical (CT) and functional images (SPECT or PET). The CT information can be used for attenuation correction, calcium scoring, spatial coregistration of myocardial perfusion defect and subtending coronary artery (Figure 5). Stress testing with NMPI incorporates multiple parameters such as MPI, gated myocardial wall motion, cardiac volumes with stress and at rest, ECG changes with stress testing, workload performance by the patient on the treadmill, blood pressure and heart rate response to exercise, and the presence or absence of symptoms with stress testing.