标题： 气体像素探测器使用二甲醚的光谱和偏振特性 characterization 显示英文标题

标题： Spectral and polarimetric characterization of the Gas Pixel Detector filled with dimethyl ether

摘要： 气体像素探测器属于为测量天体物理源的X射线偏振而优化的气体探测器中的极少数类别。 选择X射线光子被吸收和光电子传播的混合气体，对仪器的能量范围及其在增益、轨迹尺寸以及最终偏振灵敏度方面的性能有深远影响。 在这里，我们介绍了气体像素探测器的特性，该探测器使用一个1厘米厚的腔体，内部填充了二甲醚（DME），压力为0.79大气压，该混合气体因其非常低的扩散系数而被选中。 在INAF/IASF-Rome建立的校准设施中，利用接近45度的布拉格衍射，产生了几乎完全偏振且单色的光子。 我们首次在能量低至2.0 keV的情况下测量了仪器的调制因子和光谱能力，同时也测量了2.6 keV、3.7 keV、4.0 keV、5.2 keV和7.8 keV处的性能。 这些测量几乎覆盖了仪器的能量范围，并允许将所实现的灵敏度与由氦气和DME组成的标准混合气体的灵敏度进行比较。 显示英文摘要

摘要： The Gas Pixel Detector belongs to the very limited class of gas detectors optimized for the measurement of X-ray polarization in the emission of astrophysical sources. The choice of the mixture in which X-ray photons are absorbed and photoelectrons propagate, deeply affects both the energy range of the instrument and its performance in terms of gain, track dimension and ultimately, polarimetric sensitivity. Here we present the characterization of the Gas Pixel Detector with a 1 cm thick cell filled with dimethyl ether (DME) at 0.79 atm, selected among other mixtures for the very low diffusion coefficient. Almost completely polarized and monochromatic photons were produced at the calibration facility built at INAF/IASF-Rome exploiting Bragg diffraction at nearly 45 degrees. For the first time ever, we measured the modulation factor and the spectral capabilities of the instrument at energies as low as 2.0 keV, but also at 2.6 keV, 3.7 keV, 4.0 keV, 5.2 keV and 7.8 keV. These measurements cover almost completely the energy range of the instrument and allows to compare the sensitivity achieved with that of the standard mixture, composed of helium and DME.