Carbon-ion beams are increasingly used in the clinical practice for external radiotherapy treatments of deep-seated tumors. At therapeutic energies, carbon ions yield significant secondary products, including neutrons, which may be of concern for the radiation protection of the patient and personnel. We simulated the neutron yield produced by proton and carbon-ion pencil beams impinging on a clinical phantom at three different angles: 15°, 45° and 90°, with respect to the beam axis. We validated the simulated results using the measured response of organic scintillation detectors. We compared the results obtained with FLUKA 2011.2 and MCNPX 2.7.0 based on three different physics models: Bertini, Isabel, and CEM. Over the different ions, energies, and angles, the FLUKA simulation results agree better with the measured data, compared to the MCNPX results. Simulations of carbon ions at low angles exhibit both the highest deviation from measured data and inter-model discrepancy, whic...

中文翻译：

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质子和碳离子治疗束产生的中子的角分布。

碳离子束在临床实践中越来越多地用于深部肿瘤的外部放射治疗。在治疗能量下，碳离子会产生大量的副产物，包括中子，这可能会对患者和人员的辐射防护产生影响。我们模拟了质子和碳离子笔形束相对于束轴以三个不同角度（15°，45°和90°）撞击临床体模产生的中子产率。我们使用有机闪烁探测器的测量响应验证了仿真结果。我们根据三种不同的物理模型（Bertini，Isabel和CEM）比较了FLUKA 2011.2和MCNPX 2.7.0的结果。在不同的离子，能量和角度下，FLUKA模拟结果与测量数据更好地吻合，与MCNPX结果相比。低角度的碳离子模拟显示与实测数据的最大偏差以及模型间的差异，其中...