Gamma-Ray Spectroscopy With LaBr$_3$:Ce Scintillator Readout by a Silicon Drift Detector
Gamma-Ray Spectroscopy With LaBr$_3$:Ce Scintillator Readout by a Silicon Drift Detector
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DOI：
10.1109/tns.2006.878274
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发表时间：
2006
影响因子：
1.8
通讯作者：
C. Fiorini;A. Gola;M. Zanchi;A. Longoni;P. Lechner;H. Soltau;L. Struder
中科院分区：
文献类型：
--
作者：
C. Fiorini;A. Gola;M. Zanchi;A. Longoni;P. Lechner;H. Soltau;L. Struder
在本文中，作者提出了一种γ射线谱仪的基础上耦合到硅漂移探测器（SDD）的LaBr 3：Ce闪烁体。SDD是一种光电探测器，其特点是噪声非常低，这要归功于独立于有源区的输出电容值很低。相对于PMT，SDD提供了更高的量子效率，这降低了与光电子产生的统计相关的扩散。同样相对于APD，SDD提供较低的光电子统计贡献，其在APD中相对于纯泊松统计由于过量噪声因子而恶化。此外，SDD具有稳定的行为，对温度和偏置漂移不太敏感。在过去的几年中，良好的能量分辨率测量使用SDD耦合到CsI：Tl晶体。然而，长的成形时间，用于该闪烁体，以防止弹道赤字，是太远，以利用最佳的噪声性能可实现的SDD在成形时间在1 μ s的顺序。相反，这种最佳的成形时间是完全兼容的LaBr 3：Ce晶体的短衰减时间（约25纳秒）。在这项工作中的LaBr 3：Ce-SDD γ射线谱仪的实验表征的结果，并与实现相同的晶体耦合到PMT和CsI（Tl）晶体耦合到相同的SDD的性能进行比较。SDD的有效面积为30 mm 2。已经实施了抗反射涂层。由于探测器的漏电流很低，在室温下测得了良好的能量分辨率：137 Cs 661.7 KeV线为2.7%，57 Co 122 KeV线为6.1%。在0 ℃下测得122 KeV谱线的分辨率为5.7%
In this paper, the authors propose a gamma-ray spectrometer based on a LaBr3 :Ce scintillator coupled to a silicon drift detector (SDD). The SDD is a photodetector characterized by a very low noise thanks to the low value of output capacitance independent from the active area. With respect to a PMT, the SDD offers a higher quantum efficiency which reduces the spread associated to the statistic of photoelectrons generation. Also with respect to an APD, the SDD offers a lower photoelectrons statistic contribution, which, in the APD, is worsened by the excess noise factor with respect to pure Poisson statistics. Moreover, the SDD has a stable behavior, less sensitive to temperature and bias drift. In the past years, good energy resolutions were measured using a SDD coupled to a CsI:Tl crystal. However, the long shaping time, to be used with this scintillator to prevent ballistic deficit, was too far to exploit the best noise performances achievable with a SDD obtained at shaping times in the order of 1 mus. On the contrary, this optimum shaping time is fully compatible with the short decay time of the LaBr3 :Ce crystal (about 25 ns). The results of the experimental characterization of the LaBr3 :Ce-SDD gamma-ray spectrometer are presented in this work and are compared with the performances achieved with the same crystal coupled to a PMT and to a CsI(Tl) crystal coupled to the same SDD. The SDD has an active area of 30 mm2. Antireflective coatings have been implemented. Good energy resolutions were measured at room temperature, thanks to the low leakage current of the detector: 2.7% at the137 Cs 661.7 KeV line and 6.1% at the 57Co 122 KeV line. A resolution of 5.7% at 122 KeV line was measured at 0 degC