Radiation measurement and imaging using 3D position sensitive pixelated CZT detector

Younghak Kim, Taewoong Lee, Won Ho Lee

Research output: Contribution to journalArticle

Abstract

In this study, we evaluated the performance of a commercial pixelated cadmium zinc telluride (CZT) detector for spectroscopy and identified its feasibility as a Compton camera for radiation monitoring in a nuclear power plant. The detection system consisted of a 20 mm × 20 mm × 5 mm CZT crystal with 8 × 8 pixelated anodes and a common cathode, in addition to an application specific integrated circuit. The performance of the various radioisotopes 57Co, 133Ba, 22Na, and 137Cs was evaluated. In general, the amplitude of the induced signal in a CZT crystal depends on the interaction position and material non-uniformity. To minimize this dependency, a drift time correction was applied. The depth of each interaction was calculated by the drift time and the positional dependency of the signal amplitude was corrected based on the depth information. After the correction, the Compton regions of each spectrum were reduced, and energy resolutions of 122 keV, 356 keV, 511 keV, and 662 keV peaks were improved from 13.59%, 9.56%, 6.08%, and 5%–4.61%, 2.94%, 2.08%, and 2.2%, respectively. For the Compton imaging, simulations and experiments using one 137Cs source with various angular positions and two 137Cs sources were performed. Individual and multiple sources of 133Ba, 22Na, and 137Cs were also measured. The images were successfully reconstructed by weighted list-mode maximum likelihood expectation maximization method. The angular resolutions and intrinsic efficiency of the 137Cs experiments were approximately 7°–9° and 5×10−4–7×10−4, respectively. The distortions of the source distribution were proportional to the offset angle.

Original languageEnglish
Pages (from-to)1417-1427
Number of pages11
JournalNuclear Engineering and Technology
Volume51
Issue number5
DOIs
Publication statusPublished - 2019 Aug 1

Fingerprint

Cadmium
Zinc
Detectors
Imaging techniques
Radiation
Crystals
Application specific integrated circuits
Radioisotopes
Nuclear power plants
Maximum likelihood
Anodes
Cathodes
Experiments
Cameras
Spectroscopy
Monitoring

Keywords

  • Compton camera
  • Drift time method
  • Pixelated CZT detector
  • Spectroscopy

ASJC Scopus subject areas

  • Nuclear Energy and Engineering

Cite this

Radiation measurement and imaging using 3D position sensitive pixelated CZT detector. / Kim, Younghak; Lee, Taewoong; Lee, Won Ho.

In: Nuclear Engineering and Technology, Vol. 51, No. 5, 01.08.2019, p. 1417-1427.

Research output: Contribution to journalArticle

@article{c7801d29db4645efa4b34cf335e9965b,
title = "Radiation measurement and imaging using 3D position sensitive pixelated CZT detector",
abstract = "In this study, we evaluated the performance of a commercial pixelated cadmium zinc telluride (CZT) detector for spectroscopy and identified its feasibility as a Compton camera for radiation monitoring in a nuclear power plant. The detection system consisted of a 20 mm × 20 mm × 5 mm CZT crystal with 8 × 8 pixelated anodes and a common cathode, in addition to an application specific integrated circuit. The performance of the various radioisotopes 57Co, 133Ba, 22Na, and 137Cs was evaluated. In general, the amplitude of the induced signal in a CZT crystal depends on the interaction position and material non-uniformity. To minimize this dependency, a drift time correction was applied. The depth of each interaction was calculated by the drift time and the positional dependency of the signal amplitude was corrected based on the depth information. After the correction, the Compton regions of each spectrum were reduced, and energy resolutions of 122 keV, 356 keV, 511 keV, and 662 keV peaks were improved from 13.59{\%}, 9.56{\%}, 6.08{\%}, and 5{\%}–4.61{\%}, 2.94{\%}, 2.08{\%}, and 2.2{\%}, respectively. For the Compton imaging, simulations and experiments using one 137Cs source with various angular positions and two 137Cs sources were performed. Individual and multiple sources of 133Ba, 22Na, and 137Cs were also measured. The images were successfully reconstructed by weighted list-mode maximum likelihood expectation maximization method. The angular resolutions and intrinsic efficiency of the 137Cs experiments were approximately 7°–9° and 5×10−4–7×10−4, respectively. The distortions of the source distribution were proportional to the offset angle.",
keywords = "Compton camera, Drift time method, Pixelated CZT detector, Spectroscopy",
author = "Younghak Kim and Taewoong Lee and Lee, {Won Ho}",
year = "2019",
month = "8",
day = "1",
doi = "10.1016/j.net.2019.03.009",
language = "English",
volume = "51",
pages = "1417--1427",
journal = "Nuclear Engineering and Technology",
issn = "1738-5733",
publisher = "Korean Nuclear Society",
number = "5",

}

TY - JOUR

T1 - Radiation measurement and imaging using 3D position sensitive pixelated CZT detector

AU - Kim, Younghak

AU - Lee, Taewoong

AU - Lee, Won Ho

PY - 2019/8/1

Y1 - 2019/8/1

N2 - In this study, we evaluated the performance of a commercial pixelated cadmium zinc telluride (CZT) detector for spectroscopy and identified its feasibility as a Compton camera for radiation monitoring in a nuclear power plant. The detection system consisted of a 20 mm × 20 mm × 5 mm CZT crystal with 8 × 8 pixelated anodes and a common cathode, in addition to an application specific integrated circuit. The performance of the various radioisotopes 57Co, 133Ba, 22Na, and 137Cs was evaluated. In general, the amplitude of the induced signal in a CZT crystal depends on the interaction position and material non-uniformity. To minimize this dependency, a drift time correction was applied. The depth of each interaction was calculated by the drift time and the positional dependency of the signal amplitude was corrected based on the depth information. After the correction, the Compton regions of each spectrum were reduced, and energy resolutions of 122 keV, 356 keV, 511 keV, and 662 keV peaks were improved from 13.59%, 9.56%, 6.08%, and 5%–4.61%, 2.94%, 2.08%, and 2.2%, respectively. For the Compton imaging, simulations and experiments using one 137Cs source with various angular positions and two 137Cs sources were performed. Individual and multiple sources of 133Ba, 22Na, and 137Cs were also measured. The images were successfully reconstructed by weighted list-mode maximum likelihood expectation maximization method. The angular resolutions and intrinsic efficiency of the 137Cs experiments were approximately 7°–9° and 5×10−4–7×10−4, respectively. The distortions of the source distribution were proportional to the offset angle.

AB - In this study, we evaluated the performance of a commercial pixelated cadmium zinc telluride (CZT) detector for spectroscopy and identified its feasibility as a Compton camera for radiation monitoring in a nuclear power plant. The detection system consisted of a 20 mm × 20 mm × 5 mm CZT crystal with 8 × 8 pixelated anodes and a common cathode, in addition to an application specific integrated circuit. The performance of the various radioisotopes 57Co, 133Ba, 22Na, and 137Cs was evaluated. In general, the amplitude of the induced signal in a CZT crystal depends on the interaction position and material non-uniformity. To minimize this dependency, a drift time correction was applied. The depth of each interaction was calculated by the drift time and the positional dependency of the signal amplitude was corrected based on the depth information. After the correction, the Compton regions of each spectrum were reduced, and energy resolutions of 122 keV, 356 keV, 511 keV, and 662 keV peaks were improved from 13.59%, 9.56%, 6.08%, and 5%–4.61%, 2.94%, 2.08%, and 2.2%, respectively. For the Compton imaging, simulations and experiments using one 137Cs source with various angular positions and two 137Cs sources were performed. Individual and multiple sources of 133Ba, 22Na, and 137Cs were also measured. The images were successfully reconstructed by weighted list-mode maximum likelihood expectation maximization method. The angular resolutions and intrinsic efficiency of the 137Cs experiments were approximately 7°–9° and 5×10−4–7×10−4, respectively. The distortions of the source distribution were proportional to the offset angle.

KW - Compton camera

KW - Drift time method

KW - Pixelated CZT detector

KW - Spectroscopy

UR - http://www.scopus.com/inward/record.url?scp=85068059481&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85068059481&partnerID=8YFLogxK

U2 - 10.1016/j.net.2019.03.009

DO - 10.1016/j.net.2019.03.009

M3 - Article

VL - 51

SP - 1417

EP - 1427

JO - Nuclear Engineering and Technology

JF - Nuclear Engineering and Technology

SN - 1738-5733

IS - 5

ER -