A directional neutron spectrometer called NCT-WES (Neutron Capture Therapy Wide Energy Spectrometer), conceived as a spectrometric beam monitor in neutron capture therapy, was designed and prototyped. As other types of single moderator neutron spectrometers, NCT-WES condenses the functionality of Bonner Spheres in a single moderator embedding multiple thermal neutron detectors in previously optimized positions. NCT-WES is a polyethylene cylinder with 36 cm diameter and 41.5 cm height. To achieve a sharply directional response, the sensitive part is shielded with a thick barrier made of polyethylene and borated rubber, except in the direction identified by the collimating aperture. The size, geometry, materials and detector locations were previously optimized to emphasise the spectrometric capability in the epithermal range. TNPD-type thermal neutron detectors, consisting of 1 cm² silicon p-i-n diodes covered with ⁶LiF are used as internal thermal neutron detectors. The simulation model of NCT-WES was experimentally verified by exposing the prototype in the reference neutron field of ²⁴¹Am-Be available at the Politecnico di Milano. The count rate in the NCT-WES internal detectors, as calculated from the simulation model, coincided with the experimental ones within about 2%, confirming the high degree of accuracy of the NCT-WES simulation model. Aspects related to the future use of NCT-WES in therapeutic neutron beams are finally discussed.

一种称为 NCT-WES（中子俘获疗法宽能谱仪）的定向中子能谱仪被设计成中子俘获疗法中的光谱束监测器，并进行了原型设计。与其他类型的单减速器中子能谱仪一样，NCT-WES 将 Bonner Spheres 的功能浓缩在单个减速器中，在先前优化的位置嵌入多个热中子探测器。NCT-WES 是一个直径为 36 厘米、高度为 41.5 厘米的聚乙烯圆柱体。为了获得清晰的方向响应，敏感部分用聚乙烯和硼酸橡胶制成的厚屏障屏蔽，除了由准直孔识别的方向。先前优化了尺寸、几何形状、材料和探测器位置，以强调超热范围内的光谱测定能力。^{2 个}覆盖有⁶ LiF 的硅 pin 二极管用作内部热中子探测器。通过在米兰理工大学提供的²⁴¹ Am-Be参考中子场中暴露原型，对 NCT-WES 的仿真模型进行了实验验证。NCT-WES内部探测器的计数率，由仿真模型计算，与实验值的吻合度在2%左右，证实了NCT-WES仿真模型的高度准确性。最后讨论了与 NCT-WES 在治疗性中子束中的未来使用相关的方面。