论文标题
简单的Helmholtz线圈状磁屏将在降低X射线样背景下的有效性
The Effectiveness of a Simple Helmholtz coil-like Magnetic Shield at Reducing X-ray-like Background in Space-based X-ray Detectors
论文作者
论文摘要
在过去和当前的X射线天文学任务中，活跃的和被动磁性屏蔽均已广泛使用，以屏蔽探测器免受通过望远镜光学元件输入的软质子和电子。但是，在过去十年中进行的模拟发现，很大一部分X射线样背景来自X射线检测器周围X射线检测器中产生的二次电子，该探测器来自所有方向。在这里，提出了围绕检测器的简单Helmholtz线圈样磁场的GEANT4模拟的结果，发现Helmholtz线圈样磁场在防止二级电子到达检测器方面非常有效。这种磁性屏蔽方法几乎可以消除与背散射电子和完全吸收的软电子相关的所有背景，预计这些磁性电子的厚度为几百微米，约占预期的离轴背景的三分之二。这样做所需的磁场结构可以轻松地使用一组螺线管或新近磁铁磁铁来产生，如果可以对功率需求进行充分优化或分别充分地减弱，则可以分别对功率要求进行充分优化。
Both active and passive magnetic shielding have been used extensively during past and current X-ray astronomy missions to shield detectors from soft protons and electrons entering through telescope optics. However, simulations performed throughout the past decade have discovered that a significant proportion of X-ray-like background originates from secondary electrons produced in spacecraft shielding surrounding X-ray detectors, which hit detectors isotropically from all directions. Here, the results from Geant4 simulations of a simple Helmholtz coil-like magnetic field surrounding a detector are presented, and it is found that a Helmholtz coil-like magnetic field is extremely effective at preventing secondary electrons from reaching the detector. This magnetic shielding method could remove almost all background associated with both backscattering electrons and fully absorbed soft electrons, which together are expected to account for approximately two thirds of the expected off-axis background in silicon-based X-ray detectors of several hundred microns in thickness. The magnetic field structure necessary for doing this could easily be produced using a set of solenoids or neodymium magnets providing that power requirements can be sufficiently optimised or neodymium fluorescence lines can be sufficiently attenuated, respectively.
