MGGPOD: a Monte Carlo Suite for Modeling Instrumental Line and Continuum Backgrounds in Gamma-Ray Astronomy
MGGPOD: a Monte Carlo Suite for Modeling Instrumental Line and Continuum Backgrounds in Gamma-Ray Astronomy
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MGGPOD：伽马射线天文学中仪器线和连续背景建模的蒙特卡罗套件
DOI：
10.1086/425577
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
C. Ferguson
中科院分区：
文献类型：
--
作者：
G. Weidenspointner;M. Harris;M. Harris;M. Harris;S. Sturner;S. Sturner;B. Teegarden;C. Ferguson
强烈而复杂的仪器背景，必须从天体源中识别出小得多的信号，这是中低能量γ射线天文学（1050 keV-10 MeV）的一个众所周知的问题。因此，对仪器谱线和连续谱背景的详细定性和定量了解对于γ射线天文学飞行任务的大多数阶段至关重要，从设计和开发新仪器到性能预测再到数据处理。我们已经开发了MGGPOD，一个用户友好的蒙特卡罗代码套件，围绕广泛使用的GEANT（版本。3.21）包，从头模拟与仪器背景产生相关的物理过程。这些包括放射性同位素的积累和延迟衰变以及激发态原子核的迅速去激发，这两种情况除了连续谱背景外，还会产生过多的仪器γ射线背景线。MGGPOD包和文档可在线公开获取。我们展示了MGGPOD套件的能力，通过模拟1995年期间风船上的瞬态伽马射线谱仪（TGRS）记录的高分辨率γ射线谱。TGRS是一台工作在40 keV-8 MeV范围内的Ge光谱仪。由于其精细的能量分辨率，这些光谱揭示了复杂的仪器背景在可怕的细节，特别是许多即时和延迟的γ射线线。我们评估的成功和失败的MGGPOD包在再现TGRS数据，并提供众多的仪器线的标识。
Intense and complex instrumental backgrounds, against which the much smaller signals from celestial sources have to be discerned, are a notorious problem for low- and intermediate-energy γ-ray astronomy (∼50 keV-10 MeV). Therefore, a detailed qualitative and quantitative understanding of instrumental line and continuum backgrounds is crucial for most stages of γ-ray astronomy missions, ranging from the design and development of new instrumentation through performance prediction to data reduction. We have developed MGGPOD, a user-friendly suite of Monte Carlo codes built around the widely used GEANT (ver. 3.21) package, to simulate ab initio the physical processes relevant for the production of instrumental backgrounds. These include the build-up and delayed decay of radioactive isotopes as well as the prompt de-excitation of excited nuclei, both of which give rise to a plethora of instrumental γ-ray background lines in addition to continuum backgrounds. The MGGPOD package and documentation are publicly available online. We demonstrate the capabilities of the MGGPOD suite by modeling high-resolution γ-ray spectra recorded by the Transient Gamma-Ray Spectrometer (TGRS) on board Wind during 1995. The TGRS is a Ge spectrometer operating in the 40 keV-8 MeV range. Because of its fine energy resolution, these spectra reveal the complex instrumental background in formidable detail, particularly the many prompt and delayed γ-ray lines. We evaluate the successes and failures of the MGGPOD package in reproducing TGRS data and provide identifications for the numerous instrumental lines.