Environmental Radiation Center, EOSL, GTRI, Georgia Institute of Technology, Atlanta, GA 30332-0834, USA.
Health Phys. 2011 Dec;101(6):703-8. doi: 10.1097/HP.0b013e3182211172.
Gamma-ray spectral analyses with a 5-cm × 5-cm LaBr3(Ce) detector and a NaI(Tl) detector of the same size show that the LaBr3(Ce) has much better gamma-ray peak resolution and full-energy peak counting efficiency but worse detection sensitivity. The LaBr3(Ce) detector has relatively high intrinsic radiation background due to the naturally occurring La radioisotope in lanthanum. Although this La background is entirely below the energy of 1,500 keV, additional background is in the energy region between 1,500 keV and 2,750 keV. The manufacturer attributes this radiation to alpha particles emitted by the five short-lived progeny of an Ac impurity. Comparative values for peak resolution, full-energy peak counting efficiency, and detection sensitivity are reported for Am, Co, and Cs. Results of counting Cs sources at two activity levels demonstrate the impact of background on detection sensitivity.
使用 5 厘米×5 厘米的 LaBr3(Ce) 探测器和相同尺寸的 NaI(Tl) 探测器进行伽马能谱分析表明，LaBr3(Ce) 在伽马射线峰值分辨率、全能峰计数效率方面具有更好的性能，但探测灵敏度较差。由于镧中天然存在的放射性同位素镧，LaBr3(Ce) 探测器具有相对较高的固有辐射本底。尽管这种镧本底完全低于 1500keV 的能量，但在 1500keV 到 2750keV 的能量范围内仍存在额外的本底。制造商将这种辐射归因于 Ac 杂质的五个短寿命产物发射的α粒子。报告了 Am、Co 和 Cs 的峰分辨率、全能峰计数效率和探测灵敏度的比较值。在两个活度水平下对 Cs 源进行计数的结果表明了本底对探测灵敏度的影响。
