AI 中文总结
该研究基于CXPOL概念研制硬X射线光谱偏振仪，通过Geant4模拟与原型测试验证其性能，表明位置灵敏康普顿焦面仪器在下一代硬X射线光谱偏振测量中潜力巨大。
AI 中文摘要
X射线偏振测量的科学潜力早已得到认可，但测量偏振的挑战使其在硬X射线领域仍未得到充分探索。随着硬X射线聚焦光学的出现，灵敏的焦面康普顿偏振仪现已成为可能。印度物理研究实验室（PRL）研制的CXPOL（康普顿X射线偏振仪）是早期范例，该仪器采用塑料散射体和CsI(Tl)吸收体阵列，展现出20-80 keV的偏振测量能力，为后续发展奠定了基础。基于这一概念，我们评估了一种硬X射线光谱偏振仪，该仪器采用位置灵敏塑料散射体，周围环绕位置灵敏吸收探测器，这种几何结构可实现康普顿事件的有效重建，并能通过探测器内的相互作用位置和沉积能量开展偏振与光谱联合测量。我们评估了CXPOL第二版改进构型的关键性能参数，利用Geant4模拟评估了调制因子、偏振效率及结合现代硬X射线光学的预期灵敏度。我们还展示了一款100x20x5 mm³ NaI(Tl)吸收体首台原型机的表征结果，该吸收体由两端工作在符合模式下的硅光电倍增管（SiPM）阵列读出，评估了能量与位置分辨率及探测器沿程的光输出变化，符合读出还可将SiPM背景降低一个数量级。结果表明，基于位置灵敏康普顿的焦面仪器在下一代硬X射线光谱偏振测量中具有巨大潜力。
英文摘要
The scientific potential of X-ray polarimetry has long been recognized, yet the challenges of measuring polarization have left it largely unexplored, mainly in the hard X-ray regime. With the advent of hard X-ray focusing optics, sensitive focal-plane Compton polarimeters are now feasible. An early example is CXPOL (Compton X-ray Polarimeter), developed at Physical Research Laboratory (PRL), India, which demonstrated 20 - 80 keV polarimetric capabilities using a plastic scatterer and a CsI(Tl) absorber array. The CXPOL prototype demonstrated polarimetric capabilities in the 20 - 80 keV range, establishing a foundation for further development. Building on this concept, we evaluate a hard X-ray spectro-polarimeter employing a position-sensitive plastic scatterer surrounded by position-sensitive absorber detectors. This geometry enables efficient reconstruction of Compton events and allows combined polarimetric and spectroscopic measurements via interaction positions and deposited energies in the detectors. We evaluate key performance parameters of the revised configuration of the second version of the CXPOL. Using Geant4 simulations, we assess key performance parameters, including modulation factor, polarimetric efficiency, and expected sensitivity with modern hard X-ray optics. We also present the characterization results of first prototype of a 100x20x5 mm3 NaI(Tl) absorber read out on both ends by silicon photomultiplier (SiPM) array operating in coincidence, evaluating energy and position resolution and light-output variation along the detector. The coincidence readout also reduces SiPM background by an order of magnitude. The results demonstrate the strong potential of a position-sensitive Compton- based focal-plane instrument for next-generation hard X-ray spectro-polarimetry.
Comments12 pages, 9 figures, Submitted to SPIE Astronomical Telescopes + Instrumentation 2026, Comments are welcome!
