Secondary neutrons produced in particle therapy (PT) treatments are responsible for the delivery of a large fraction of the out-of-target dose as they feebly interact with the patient body. To properly account for their contribution to the total dose delivered to the patient, a high precision experimental characterisation of their production energy and angular distributions is eagerly needed. The experimental challenge posed by the detection and tracking of such neutrons will be addressed by the MONDO tracker: a compact scintillating fiber detector exploiting single and double elastic scattering interactions allowing for a complete neutron four-momentum reconstruction. To achieve a high detection efficiency while matching the fiber (squared, 250 μm side) high granularity, a single photon sensitive readout has been developed using the CMOS-based SPAD technology. The readout sensor, with pixels of 125×250 μm2 size, will be organised in tiles covering the full detector surface and will implement an autotrigger strategy to identify the events of interest. The expected detector performance in the context of neutron component characterisation in PT treatments delivered using carbon ions has been evaluated using a Monte Carlo simulation accounting for the detector response and the neutrons production spectra.

粒子疗法（PT）疗法中产生的次级中子由于与患者身体之间的微弱相互作用而负责输送大部分超出目标剂量的剂量。为了适当地考虑它们对输送给患者的总剂量的贡献，急需对其生产能量和角度分布进行高精度的实验表征。MONDO跟踪器将解决检测和跟踪此类中子带来的实验挑战：紧凑的闪烁纤维检测器，利用单弹性和双弹性散射相互作用实现完整的中子四动量重建。为了在匹配光纤（平方，250 微米侧）高粒度，已使用基于CMOS的SPAD技术开发了一个光子敏感的读数。读数传感器，像素为125×250 微米2大小，将以覆盖整个探测器表面的图块进行组织，并将实施自动触发策略以识别感兴趣的事件。使用考虑到探测器响应和中子产生光谱的蒙特卡洛模拟，已经对使用碳离子进行的PT处理中中子成分表征中预期的探测器性能进行了评估。