Calibration of the Gamma-RAy Polarimeter Experiment (GRAPE) at a polarized hard X-ray beam
Calibration of the Gamma-RAy Polarimeter Experiment (GRAPE) at a polarized hard X-ray beam
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DOI：
10.1016/j.nima.2008.11.118
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发表时间：
2008-12
影响因子：
1.4
通讯作者：
P. Bloser;J. Legere;M. McConnell;J. Macri;C. Bancroft;T. Connor;J. Ryan
中科院分区：
文献类型：
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作者：
P. Bloser;J. Legere;M. McConnell;J. Macri;C. Bancroft;T. Connor;J. Ryan
伽玛射线偏振计实验（英语：Gamma-RAy Polarimeter Experiment，GRAPE）是一个天文硬X射线康普顿偏振计的概念，工作在50- 500 keV的能量带。该仪器经过优化，可用于伽马射线爆发和太阳耀斑等高能天体瞬时爆发的宽场偏振测量。GRAPE仪器由相同的模块组成，每个模块由多阳极光电倍增管（MAPMT）读出的闪烁体元件阵列组成。入射光子在塑料闪烁体元件中康普顿散射，随后在无机闪烁体元件中被吸收;净偏振信号由方位角散射角的特征不对称性揭示。我们已经构建了一个原型GRAPE模块，包含一个单一的CsI（Na）量热计元件，在中心的MAPMT，由60个塑料元件包围。该原型已与定制的读出电子和软件相结合，以创建一个完整的“工程模型”的GRAPE仪器。这个工程模型已被校准使用近100%的偏振硬X射线束在先进的光子源在阿贡国家实验室。在69.5keV和129.5keV处，我们发现调制因子分别为0.46±0.06和0.48±0.03，与Monte Carlo模拟结果吻合得很好。在本文中，我们提出了详细的光束测试，数据分析和模拟，并讨论了我们的研究结果的GRAPE概念的进一步发展的影响。
The Gamma-RAy Polarimeter Experiment (GRAPE) is a concept for an astronomical hard X-ray Compton polarimeter operating in the 50–500keV energy band. The instrument has been optimized for wide-field polarization measurements of transient outbursts from energetic astrophysical objects such as gamma-ray bursts and solar flares. The GRAPE instrument is composed of identical modules, each of which consists of an array of scintillator elements read out by a multi-anode photomultiplier tube (MAPMT). Incident photons Compton scatter in plastic scintillator elements and are subsequently absorbed in inorganic scintillator elements; a net polarization signal is revealed by a characteristic asymmetry in the azimuthal scattering angles. We have constructed a prototype GRAPE module containing a single CsI(Na) calorimeter element, at the center of the MAPMT, surrounded by 60 plastic elements. The prototype has been combined with custom readout electronics and software to create a complete “engineering model” of the GRAPE instrument. This engineering model has been calibrated using a nearly 100% polarized hard X-ray beam at the Advanced Photon Source at Argonne National Laboratory. We find modulation factors of 0.46±0.06 and 0.48±0.03 at 69.5 and 129.5keV, respectively, in good agreement with Monte Carlo simulations. In this paper we present details of the beam test, data analysis, and simulations, and discuss the implications of our results for the further development of the GRAPE concept.