Health Phys. 2024 May 1;126(5):268-271. doi: 10.1097/HP.0000000000001785.
The performance of a LaBr3(Ce) gamma spectrometer at high count rates was investigated up to an input count rate of 1.3 Mcps. In order to make its pulse processing faster, a preamplifier provided by the detector manufacturer was eliminated, and the signal from the photomultiplier tube was fed directly to a digital pulse processing system. To accomplish both fast pulse processing and good energy resolution, the pulse-shaping parameters were optimized at a low count rate of 1.5 kcps, and then measurements were carried out at various count rates. Input count rates ranging from 1.5 kcps to 21 kcps were produced using a set of 137Cs resin sources, while higher rates between 45 kcps and 1.3 Mcps were produced using a 1.2-GBq 137Cs source. The spectrometer showed an excellent performance for the input rate up to 150 kcps, while the dead time increased rapidly for the input rates above 150 kcps. The system dead time has been improved greatly by eliminating the preamplifier.
研究了 LaBr3(Ce) 伽马谱仪在高达 1.3 Mcps 的输入计数率下的性能。为了使其脉冲处理更快，我们去除了探测器制造商提供的前置放大器，并将光电倍增管的信号直接馈送到数字脉冲处理系统。为了实现快速的脉冲处理和良好的能量分辨率，我们在低计数率 1.5 kcps 下优化了脉冲成形参数，然后在各种计数率下进行了测量。使用一组 137Cs 树脂源产生了输入计数率在 1.5 kcps 至 21 kcps 之间的范围，而使用 1.2-GBq 的 137Cs 源则产生了在 45 kcps 至 1.3 Mcps 之间的更高计数率。该谱仪在输入率高达 150 kcps 的情况下表现出优异的性能，而在输入率高于 150 kcps 时，死时间迅速增加。通过去除前置放大器，系统的死时间得到了很大的改善。
