论文标题
气球阳离子孔顿偏光仪的数据分析
Data Analysis for a Balloon Borne Compton Polarimeter
论文作者
论文摘要
伽玛射线极化计实验（葡萄）是一种气球阳离子孔顿偏振仪，用于50-500 kev伽马射线，于2014年第二次成功飞行。葡萄由24个准直翼仪模块组成。每个模块均由64个矩形闪光灯元件组成，网格为8 $ \ times $ 8（36个被28个CSI闪烁体包围的塑料闪烁器）。葡萄使用2个检测器元件之间的光子散射事件来测量测得的光子的极化。葡萄是从9月26日上午从新墨西哥州萨姆纳堡飞行的，$^{\ text {th}} $ 2014。葡萄在浮动高度处于14.4小时，观察到螃蟹（主要目标）1.8小时（最初计划持续8小时）。背景主导着飞行高度的观察结果，这取决于许多飞行和仪器参数（高度，仪器指向，温度等）。实施了基于原理分析（PCA）的技术，该技术使用不同的参数来估计螃蟹的背景。我们的仪器设计允许光学串扰（已知的问题），该光伴随着闪烁元件并溢出到相邻阳极而产生的光。开发了一个模型来代表串扰，该模型已纳入我们的模拟和仪器响应中。该分析的重点是相结合的数据（由于观察期缩短的统计数据有限）。测量了具有1.70 $ \ pm $ 0.24的光子指数的幂律频谱，并测量了1.01 $ \ pm $ 1.35 pH/kev/kev/s/cm $^2 $的标准化。在70-200 kev Energy系列中测量了0.43 $ \ pm $ 0.4 $ 0.4 $ 0.4和56 $^\ CIRC $ 30 $^\ CIRC $的极化角度。该结果不足以进一步了解我们对排放机制的理解。
The Gamma RAy Polarimeter Experiment (GRAPE), a balloon borne Compton polarimeter for 50-500 keV gamma rays, was successfully flown for the second time in 2014. GRAPE consists of 24 collimated polarimeter modules. Each module is made up of 64 rectangular scintillators elements in a grid of 8 $\times$ 8 (36 plastic scintillators surrounded by 28 CsI scintillators). GRAPE uses photon scattered events between 2 detector elements to measure the polarization of the measured photons. GRAPE was flown from Fort Sumner, New Mexico on the morning of September 26$^{\text{th}}$ 2014. GRAPE was at float altitude for 14.4 hours and the Crab (primary target) was observed for 1.8 hours (initially planned for 8 hours). Background dominates the observations at flight altitudes, which depends on many flight and instrument parameters (altitude, instrument pointing, temperatures, etc). A technique based on the Principle Component Analysis (PCA) was implemented which used the varying parameters to estimate the background for the Crab. Our instrument design allows for an optical crosstalk (a known issue) that arises from light exiting the scintillator element and spilling to neighboring anodes. A model was developed to represent the crosstalk, which was incorporated in our simulations and the instrument response. The analysis was focused on the phase-integrated data (due to limited statistics of the shortened observation period). A power-law spectrum with photon index of 1.70$\pm$0.24 and a normalization of 1.01$\pm$1.35 ph/keV/s/cm$^2$ was measured. A polarization fraction of 0.43$\pm$0.4 and a polarization angle of 56$^\circ \pm$30$^\circ$ was measured for the phase integrated Crab observation in the 70-200 keV energy range. This result was not sufficiently significant enough to further our understanding of the emission mechanism.
