ELIMAIA--ELIMED激光驱动质子束线在23.45 MeV下的相对与绝对剂量学调试
Relative and absolute dosimetric commissioning of the ELIMAIA--ELIMED laser-driven proton beamline at 23.4 MeV
- Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud（意大利国家核物理研究所南方实验室）
- Centro Siciliano di Fisica Nucleare e Struttura della Materia（西西里核物理与物质结构中心）
- The Extreme Light Infrastructure ERIC（极光大基础设施欧洲研究联盟）
- Extreme Light Infrastructure - Nuclear Physics (ELI-NP)（极光大基础设施-核物理（ELI-NP））
- Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH)（霍里亚·胡利贝伊物理与核工程研发国家研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究完成ELIMAIA--ELIMED激光驱动质子束线的剂量学调试，通过辐射变色膜、法拉第杯等测量及蒙特卡罗模拟，确立剂量学链并明确在线监测系统运行极限。
AI中文摘要：
面向生物医学与放射生物学应用的激光驱动质子束线研发，要求在辐照点具备可溯源的剂量测量与可靠的在线监测能力。本研究在ELI Beamlines装置中，针对ELIMAIA--ELIMED激光驱动质子束线，采用平均能量约24 MeV的能量选择质子束，开展相对与绝对剂量学调试。采用辐射变色膜（RCF）测量，表征辐照点的横向剂量分布、深度-剂量曲线及质子能谱；重建的能谱中心为23.45 MeV，半高全宽（FWHM）为2.60 MeV，横向剂量分布显示约5.5 mm的野尺寸，且存在毫米级均匀区域。采用法拉第杯（FC）作为水剂量测定的绝对参考探测器，并对作为主要在线剂量监测器的双间隙电离室进行交叉校准；同时评估了积分电流变压器（ICT）和次级电子监测器（SEM）作为上游相对束流监测器的性能。对50次连续脉冲开展的独立RCF-FC剂量比对显示，FC测得剂量为30.45±3.5 cGy，EBT3型RCF测得剂量为36.46±1.8 cGy。专用的G4ELIMED蒙特卡罗模拟表明，位于FC上游的RCF会通过FC接收范围外的质子损失，以及FC入口处有效束流面积的增大，干扰FC的测量；应用模拟得到的修正因子C_MC=1.109后，FC与RCF所得剂量的残余差异降至约7%。上述结果确立了当前低注量调试条件下ELIMAIA--ELIMED束线的剂量学链，并明确了在线监测系统的运行极限。
英文摘要：
The development of laser-driven proton beamlines for biomedical and radiobiological applications requires traceable dosimetry and reliable online monitoring at the irradiation point. In this work, we report the relative and absolute dosimetric commissioning of the ELIMAIA--ELIMED laser-driven proton beamline at ELI Beamlines using an energy-selected proton beam with an average energy of about 24~MeV. Radiochromic-film measurements were used to characterize the transverse dose distribution, the depth--dose profile, and the proton energy spectrum at the irradiation point. The reconstructed spectrum was centred at $23.45~\mathrm{MeV}$ with a FWHM of $2.60~\mathrm{MeV}$, while the transverse dose distribution showed an approximately $5.5~\mathrm{mm}$ field size with a millimetre-scale homogeneous region. The Faraday Cup was used as the absolute reference detector for dose to water determination and for cross-calibrating the Dual-Gap Ionization Chamber, which was operated as the primary online dose monitor. The Integrating Current Transformer and Secondary Electron Monitor were evaluated as upstream relative beam monitors. An independent RCF--FC dose comparison performed over fifty consecutive shots yielded $30.45 \pm 3.5~\mathrm{cGy}$ from the FC and $36.46 \pm 1.8~\mathrm{cGy}$ from the EBT3 film. Dedicated G4ELIMED Monte Carlo simulations showed that the RCF positioned upstream of the FC perturbs the FC measurement through proton losses outside the FC acceptance and through an increase in the effective beam area at the FC entrance. Applying the resulting correction factor, $C_{\mathrm{MC}}=1.109$, reduced the residual difference between the FC- and RCF-derived doses to about $7\%$. These results establish the dosimetric chain of the ELIMAIA--ELIMED beamline under the present low-fluence commissioning conditions and identify the operational limits of the online monitoring system.
