Certain proton reactions emit fast neutrons, and this study examines the feasibility of measuring the neutrons emitted from a typical medical 18 MeV proton cyclotron using prompt gamma neutron activation on chlorine. This neutron detection method, employed by previous studies, has been deemed successful and highly promising. The measurement system includes a gamma radiation scintillator, for example NaI(Tl), with a spectrometry setup facing a convertor that contains a chlorine solution or compounds thereof.

In its natural state, elemental chlorine is a chemically unstable gas, making its use as a convertor challenging. Therefore, chlorine is usually dissolved in solutions. Such solutions are diluted with water and contain hydrogen atoms that interact intensively with the neutrons and may interrupt their detection.

Accordingly, in this study, a 25.5 L container of KCl powder was placed in front of a NaI(Tl) (7.62 cm diameter by 7.62 cm length) spectrometer near a cyclotron facility. The gamma radiation spectroscopy allowed the identification of the chlorine INS gamma line at 788 keV, alongside the K-40 gamma peak. In addition, it was possible to detect the fast neutrons using a total-counting mode, when the INS counts appear above the K-40 counting level.

The chlorine INS peak in the KCl convertor was detected simultaneously during the cyclotron operations and provided a direct indication of neutron exposure around the cyclotron. We conclude that using KCl as a converter, with a NaI(Tl) gamma rays counter, is successful in detecting cyclotron-produced neutron emissions.

某些质子反应会发射快中子，本研究检验了使用氯的瞬发伽马中子活化测量典型医用 18 MeV 质子回旋加速器发射的中子的可行性。以前的研究采用的这种中子检测方法被认为是成功的并且很有前途。测量系统包括伽马辐射闪烁体，例如NaI(Tl)，其光谱设置面向包含氯溶液或其化合物的转换器。

在自然状态下，元素氯是一种化学不稳定的气体，使其用作转化器具有挑战性。因此，氯通常溶解在溶液中。这种溶液用水稀释并含有氢原子，这些氢原子与中子强烈相互作用，可能会中断它们的检测。

因此，在本研究中，将一个 25.5 L 的 KCl 粉末容器放置在靠近回旋加速器设施的 NaI(Tl)（直径 7.62 厘米，长度 7.62 厘米）光谱仪前面。伽马辐射光谱允许在 788 keV 处识别氯 INS 伽马线，以及 K-40 伽马峰。此外，当 INS 计数出现在 K-40 计数水平以上时，可以使用总计数模式检测快中子。

在回旋加速器操作期间同时检测到 KCl 转化器中的氯 INS 峰，并提供了回旋加速器周围中子暴露的直接指示。我们得出结论，使用 KCl 作为转换器，使用 NaI(Tl) 伽马射线计数器，可以成功检测回旋加速器产生的中子发射。