Maughan R L, Yudelev M, Kota C
Gershenson Radiation Oncology Center, Harper Hospital, Detroit, MI, USA.
Phys Med Biol. 1996 Aug;41(8):1341-51. doi: 10.1088/0031-9155/41/8/007.
The kU value of a commercially available miniature energy compensated Geiger-Müller (GM) detector has been determined using the modified lead attenuation method of Hough. The measurements were made in a d(48.5)-Be neutron beam produced by the superconducting cyclotron based neutron therapy facility at Harper Hospital. The unique problems associated with making measurements in a 2 ms duration pulsed beam with a 20% duty cycle are discussed. The beam monitoring system, which allows the beam pulse shape at low beam intensities to be measured, is described. By gating the GM output with a discriminator pulse derived from the beam pulse shape, the gamma-ray count rates and dead-time corrections within the 2 ms pulse and between pulses can be measured separately. The kU value of (0.0245 +/- 0.0015) determined for this GM detector is consistent with the values measured by other workers with identical and similar detectors in neutron beams with comparable, but not identical, neutron spectra.
已使用霍夫改进的铅衰减法测定了一种市售微型能量补偿盖革-米勒（GM）探测器的kU值。测量是在哈珀医院基于超导回旋加速器的中子治疗设施产生的d（48.5）-铍中子束中进行的。讨论了在占空比为20%、持续时间为2 ms的脉冲束中进行测量所涉及的独特问题。描述了一种能够测量低束流强度下束脉冲形状的束流监测系统。通过用从束脉冲形状导出的鉴别器脉冲对GM输出进行选通，可以分别测量2 ms脉冲内和脉冲之间的伽马射线计数率及死时间校正。为该GM探测器测定的kU值为（0.0245±0.0015），与其他研究人员在具有可比但不完全相同中子能谱的中子束中，使用相同和类似探测器测量的值一致。
