14C autoradiography with an energy-sensitive silicon pixel detector
14C autoradiography with an energy-sensitive silicon pixel detector
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DOI：
10.1088/0031-9155/56/7/003
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发表时间：
2011-04-07
影响因子：
3.5
通讯作者：
Russo, P.
中科院分区：
文献类型：
--
作者：
Esposito, M.;Mettivier, G.;Russo, P.
介绍了基于Timepix读出电路的碳-14 (C-14) β粒子数字放射自显影系统的首次性能测试，该系统具有能量敏感混合硅像素检测器。Timepix是由Medipix2协作开发的，它类似于光子计数的Medipix2电路，除了增加了一个基于时间的同步逻辑，允许从时间超过阈值的信号中推导能量信息。该特性允许在探测器阵列的每个像素中直接测量能量。Timepix与300 μ m厚、256 × 256像素、55 μ m间距的硅探测器磕碰结合。由于高能β粒子在半导体探测器中减速时会在多个探测器像素中释放其动能，因此采用离线图像分析程序，识别撞击像素的单粒子簇；计算了其总能量，并将相互作用在探测器表面的位置归因于电荷簇的中心。测量结果为探测器灵敏度（4.11 +/- 0.03）× 10(-3) cps mm(-2) kBq(-1) g，背景水平（3.59 +/- 0.01）× 10(-5) cps mm(-2)，最小可检测活度0.0077 Bq。半最大时全宽空间分辨率为76.9 μ m。这些数字与几种用于C-14粒子数字放射自显影的数字成像探测器进行了比较。
The first performance tests are presented of a carbon-14 (C-14) beta-particle digital autoradiography system with an energy-sensitive hybrid silicon pixel detector based on the Timepix readout circuit. Timepix was developed by the Medipix2 Collaboration and it is similar to the photon-counting Medipix2 circuit, except for an added time-based synchronization logic which allows derivation of energy information from the time-over-threshold signal. This feature permits direct energy measurements in each pixel of the detector array. Timepix is bump-bonded to a 300 mu m thick silicon detector with 256 x 256 pixels of 55 mu m pitch. Since an energetic beta-particle could release its kinetic energy in more than one detector pixel as it slows down in the semiconductor detector, an off-line image analysis procedure was adopted in which the single-particle cluster of hit pixels is recognized; its total energy is calculated and the position of interaction on the detector surface is attributed to the centre of the charge cluster. Measurements reported are detector sensitivity, (4.11 +/- 0.03) x 10(-3) cps mm(-2) kBq(-1) g, background level, (3.59 +/- 0.01) x 10(-5) cps mm(-2), and minimum detectable activity, 0.0077 Bq. The spatial resolution is 76.9 mu m full-width at half-maximum. These figures are compared with several digital imaging detectors for C-14 beta-particle digital autoradiography.