| 用单一光源标定光子计数探测器 |
| 冯初晴, 沈淇, 康克军, 邢宇翔 |
| 清华大学 工程物理系, 粒子技术与辐射成像教育部重点实验室, 北京 100084 |
| Energy calibration of photon counting detectors using a single monochromatic source |
| FENG Chuqing, SHEN Qi, KANG Kejun, XING Yuxiang |
| Key Laboratory of Particle and Radiation Imaging of Ministry of Education, Department of Engineering Physics, Tsinghua University, Beijing 100084, China |
摘要:
| |||
| 摘要光子计数探测器在X光能谱CT成像中应用越来越广泛。受到脉冲堆叠、 电荷共享等物理作用的影响, 目前的光子计数探测器的能量标定方法具有一定的局限性。该文提出了一种只用一个单能光源对探测器进行标定的方法, 通过充分挖掘及利用有限的数据, 运用迭代的方法, 最终确定探测器各阈值所对应的能量。该方法不仅实验量小, 操作简单, 标定结果较准确, 还考虑了对小像素探测器标定有较大影响的电荷共享问题, 且具有普适性, 对其他光子计数探测器的标定也有一定的帮助。 | |||
| 关键词 ：光子计数探测器,能谱CT,能量标定,电荷共享 | |||
| Abstract：Photon counting detectors (PCDs) are important in spectral X-ray imaging and computed tomography (CT) systems. Various PCD energy calibration methods have been developed but have many limitations because of the influences of the pulse pileup, charge sharing and other physical effects. This paper describes a calibration method using only one monochromatic source. An iterative technique is used to fully analyze the data to determine the energy for various thresholds. The method gives good results with fewer tests than other calibration methods. The charge sharing effect is implicitly corrected, which is an important factor in the calibration of small pixel detectors. This method is quite universal and can be used to calibrate other PCDs. | |||
| Key words：photon counting detectorspectral computed tomography (CT)energy calibrationcharge sharing | |||
| 收稿日期: 2014-12-09 出版日期: 2016-07-01 | |||
| |||
| 通讯作者:邢宇翔, 副研究员, E-mail: xingyx@tsinghua.edu.cnE-mail: xingyx@tsinghua.edu.cn | |||
| 引用本文: |
| 冯初晴, 沈淇, 康克军, 邢宇翔. 用单一光源标定光子计数探测器[J]. 清华大学学报（自然科学版）, 2016, 56(6): 672-676. FENG Chuqing, SHEN Qi, KANG Kejun, XING Yuxiang. Energy calibration of photon counting detectors using a single monochromatic source. Journal of Tsinghua University(Science and Technology), 2016, 56(6): 672-676. |
| 链接本文: |
| http://jst.tsinghuajournals.com/CN/10.16511/j.cnki.qhdxxb.2016.22.031或 http://jst.tsinghuajournals.com/CN/Y2016/V56/I6/672 |
图表:
 |
| 图１ 确定TOTＧE 关系的迭代步骤流程图 |
 |
| 图２ 光子计数探测器标定实验装置 |
 |
| 图３ 未校正的单色光源２４１Am 的TOT能谱 |
 |
| 图４ 校正后的放射性同位素２４１Am 源的TOT能谱 |
 |
| 图５ 光子计数探测器不同阈值[５０,９０]所对应的能量 |
 |
| 图６ 未校正的放射性同位素１５５Eu源的TOT能谱 |
 |
| 图７ 校正后的放射性同位素１５５Eu源的TOT能谱 |
参考文献:
| [1] Llopart X, Campbell M, San Segundo D, et al. Medipix2, a 64k pixel read out chip with 55 μm square elements working in single photon counting mode [C]//Nuclear Science Symposium Conference Record, 2001 IEEE. San Diego, CA, USA, 2001, 3: 1484-1488. [2] Llopart X, Ballabriga R, Campbell M, et al. Timepix, a 65k programmable pixel readout chip for arrival time, energy and/or photon counting measurements [J]. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2007, 581(1): 485-494. [3] Fiederle M, Greiffenberg D, Idárraga J, et al. Energy calibration measurements of MediPix2 [J]. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2008, 591(1): 75-79. [4] Pellegrini G, Chmeissani M, Maiorino M, et al. Performance limits of a 55 μm pixel CdTe detector [C]//Nuclear Science Symposium Conference Record, 2004 IEEE. Rome, Italy, 2004, 4: 2104-2109. [5] Ponchut C. Correction of the charge sharing in photon-counting pixel detector data [J]. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2008, 591(1): 311-313. [6] Taguchi K, Iwanczyk J S. Vision 20/20: Single photon counting X-ray detectors in medical imaging [J]. Medical Physics, 2013, 40(10), 100901. [7] Greiffenberg D, Fauler A, Zwerger A, et al. Energy resolution and transport properties of CdTe-Timepix-Assemblies [J]. Journal of Instrumentation, 2011, 6(1), C01058. [8] Zwerger A, Fauler A, Fiederle M, et al. Medipix2: Processing and measurements of GaAs pixel detectors [J]. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2007, 576(1): 23-26. [9] Jakubek J, Cejnarova A, Holy T, et al. Pixel detectors for imaging with heavy charged particles [J]. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2008, 591(1): 155-158. [10] Youn H, Han J C, Kam S, et al. Energy calibration of energy-resolved photon-counting pixel detectors using laboratory polychromatic X-ray beams [J]. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2014, 760: 79-85. [11] Jakubek J. Precise energy calibration of pixel detector working in time-over-threshold mode [J]. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2011, 633: S262-S266. [12] Ponchut C, Ruat M. Energy calibration of a CdTe X-ray pixel sensor hybridized to a Timepix chip [J]. Journal of Instrumentation, 2013, 8(1), C01005. |
相关文章:
| ||
