Calibration of the NuSTAR High Energy Focusing X-ray Telescope
Kristin K. Madsen, Fiona A. Harrison, Craig B. Markwardt, Hongjun An, Brian W. Grefenstette, Matteo Bachetti, Hiromasa Miyasaki, Takao Kitaguchi, Varun Bhalerao… 展开作者
Kristin K. Madsen, Fiona A. Harrison, Craig B. Markwardt, Hongjun An, Brian W. Grefenstette, Matteo Bachetti, Hiromasa Miyasaki, Takao Kitaguchi, Varun Bhalerao, Steve Boggs, Finn E. Christensen, William W. Craig, Karl Forster, Felix Fuerst, Charles J. Hailey, Matteo Perri, Simonetta Puccetti, Vikram Rana, Daniel Stern, Dominic J. Walton, Niels Jørgen Westergaard, William W. Zhang
We present the calibration of the \textit{Nuclear Spectroscopic Telescope Array} (\nustar) X-ray satellite. We used the Crab as the primary effective area calibrator and constructed a piece-wise linear spline function to modify the vignetting response. The achieved residuals for all off-axis angles and energies, compared to the assumed spectrum, are typically better than $\pm 2$\% up to 40\,keV and 5--10\,\% above due to limited counting statistics. An empirical adjustment to the theoretical 2D point spread function (PSF) was found using several strong point sources, and no increase of the PSF half power diameter (HPD) has been observed since the beginning of the mission. We report on the detector gain calibration, good to 60\,eV for all grades, and discuss the timing capabilities of the observatory, which has an absolute timing of $\pm$ 3\,ms. Finally we present cross-calibration results from two campaigns between all the major concurrent X-ray observatories (\textit{Chandra}, \textit{Swift}, \textit{Suzaku} and \textit{XMM-Newton}), conducted in 2012 and 2013 on the sources 3C\,273 and PKS\,2155-304, and show that the differences in measured flux is within $\sim$10\% for all instruments with respect to \nustar.
In-flight PSF calibration of the NuSTAR hard X-ray optics
本文介绍了核光谱望远镜阵列（NuSTAR）硬X射线光学系统的点扩散函数（PSF）标定结果。在发射后不久，NuSTAR就观测到了Cyg X-1、Vela X-1和Her X-1等亮点源，用于PSF校准。我们使用的点源观测在几个离轴角度与射线跟踪模型来表征在轨道上的角响应，并发现射线跟踪模型单独不适合所观察到的事件分布和应用经验校正的射线跟踪模型，提高了拟合显着。我们描述了应用于射线跟踪模型的修正，并表明新PSF模型的封闭能量分数（EEF）的不确定性为< 3% for extraction apertures of R >60”，没有显着的能量依赖性。我们还表明，在其在轨运行期间，NuSTAR光学器件的PSF在约300天的时间内一直保持稳定。
Spectral calibration and modeling of the NuSTAR CdZnTe pixel detectors
核光谱望远镜阵列（NuSTAR）将是第一个聚焦于硬X射线（5-80 keV）波段的空间飞行任务。NuSTAR仪器携带两个共对准掠入射硬X射线望远镜。每个NuSTAR焦平面由四个2 mm CdZnTe混合像素探测器组成，每个探测器的有效收集面积为2 cm x 2 cm。每个混合电路由一个32 x 32的605微米像素阵列组成，用加州理工学院定制的低噪声NuCIT ASIC读出。为了将每个像素的光谱响应特性描述为满足科学校准要求所需的程度，我们开发了一个基于Geant 4的模型，并为NuSTAR混合设计定制了Shockley-Ramo定理。该模型结合了蒙特卡罗的X射线相互作用与随后的电荷传输内的检测器。使用Co-57，Eu-155和Am-241的放射性源的该模型和校准数据的组合使我们能够确定每个像素的电子和空穴迁移率寿命产品，并将实际性能与无缺陷材料的理想性能进行比较。
University of Leicester（莱斯特大学）；Space Park Leicester, University of Leicester（莱斯特大学太空公园）；School of Physics and Astronomy, University of Leicester（莱斯特大学物理与天文学院）；Ctr National d’Études Spatiales（法国国家空间研究中心）；AIM-CEA/DRF/Irfu/Departement d’Astrophysique, Universite Paris-Saclay（巴黎萨克雷大学天体物理学系）
