Measurement of the distance to gamma-ray burst surces

在观测氢柱密度到伽玛射线暴源时，需要1 keV以下的软X射线光子，从那里我们可以测量到源的距离。需要X射线检测器的低漏电流来检测这样的软X射线光子。与硅不同，高纯度金刚石具有非常高的天然电阻率。与硅的1.1eV相比，金刚石的能带隙也非常大，为5.5eV。因此，即使施加高电场，也只有微弱的电流流过探测器。我们用天然金刚石、化学气相沉积（CVD）金刚石和高压合成金刚石等几种金刚石制作了辐射传感器。结果表明，高压合成金刚石传感器对5.486MeV的α粒子具有25.4keV（FWHM）的能量分辨率<241>，远优于天然金刚石的82keV（FWHM）。获得的能量分辨率几乎与硅传感器相当，为未来的伽玛暴X射线探测器提供了有希望的数据。

Soft X-ray photons below 1 keV are required to observe the hydrogen column density to gamma-ray burst sources from which we can measure the distance to the source. A low leakage current of the X-ray detector is required to detect such a soft X-ray photon. Unlike silicon, high purity diamond exhibits a very high natural resistivity. Diamond also has a very large energy band gap of 5.5 eV compared with that of silicon of 1.1 eV.Thus, even with the application of a high electric field, only a feeble current flows through the detector.We produced the radiation sensor from several kinds of diamonds such as natural diamonds, chemical vapor deposited (CVD) diamonds, and high pressure synthesized diamonds. As a result, it was found that the sensor of a high pressure synthesized diamond has the excellent energy resolution of 25.4 keV (FWHM) for 5.486 MeV alpha particles from ^<241>Am, which ismuch better than the previously reported value of 82 keV (FWHM) of the natural diamond. The obtained energy resolution is almost the same as silicon sensor and a promising data for the future X-ray detector of gamma-ray bursts.