Beach J L, McCullough E C
Med Phys. 1975 Jul-Aug;2(4):213-5. doi: 10.1118/1.594181.
An inexpensive recoil-proton counter telescope has been designed for absolute fluence measurements of a gas-target neutron source for radiation therapy. The detector has an absolute efficiency of 1.1 times 10-minus 9 at 20 cm from an isotropic source and is useful for production rates of 10-9 minus 10-13 neutrons per second. The telescope consists of a thin hydrogenous irradiator foil and a surface-barrier detector to count recoil protons within a defined solid angle. The telescope provides n-gamma discrimination as well as discrimination against scattered neutrons. Initial tests of the counter telescope were performed using the DD reaction employed in development stages of the gas target. A clear separation of full-energy recoil protons from background and scattered neutron events was evident in the pulse-height spectra without the use of coincidence gating techniques.
已设计出一种价格低廉的反冲质子计数望远镜，用于对用于放射治疗的气体靶中子源进行绝对注量测量。该探测器在距各向同性源20厘米处的绝对效率为1.1×10⁻⁹，适用于每秒10⁻⁹至10⁻¹³个中子的产额。该望远镜由一片薄的含氢辐照箔和一个表面势垒探测器组成，用于在限定的立体角内计数反冲质子。该望远镜可实现n-γ鉴别以及对散射中子的鉴别。使用气体靶开发阶段采用的D-D反应对计数望远镜进行了初步测试。在不使用符合选通技术的情况下，脉冲高度谱中全能量反冲质子与本底和散射中子事件能明显清晰分离。
