Development of NIS type superconducting radiation detectors with enlarged sensitive area by segmented absorbers

2001年，制备了真空室，配备了用于铌和农业溅射的华盛顿磁控管，用于铝溅射的射频磁控管和用于SiO2的电子束蒸发器。对于超导辐射探测器的图形，采用了精确的X-Y- z级，而不是以前的X-Y级。利用该装置，确定了铌、铝、农业和SiO_2薄膜的制备条件。利用精确的X-Y- z级，以10μm的模糊度进行了模式定义，明显优于X-Y级的50μm。此外，我们还发明了热开关方法来扩大NIS型超导体辐射探测器的吸收面积。2002年，我们利用squid发明了三种方法来提高NIS探测器的能量分辨率：(1)不对称调制squid，(2)带超导体环路的Josephson结微热量计，(3)Rf-SQUID微热量计。这些探测器具有与普通金属吸收器耦合的约瑟夫森结。用SQUID测量辐射能量为约瑟夫森结临界电流随电子温度升高的变化。在100k的工作温度下，三种方法的能量分辨率均可达到1.5 ~ 5.8eV。

In 2001, a vacuum chamber was fabricated, equipped with Washington, D. C. magnetrons for Nb and Agriculture sputtering, RF magnetron for Al sputtering and electron-beam evaporator for SiO2.For the patterning of superconducting radiation detector, precise X-Y-Z stage was employed, instead of previous X-Y stage. With these equipment, the fabricating conditions for thin films of Nb, Al, Agriculture, and SiO_2 were determined. With the precise X-Y-Z stage, pattern definition was done with the ambiguity of 10μm, which was much better than 50μm with X-Y stage. Moreover, we invented heat-switch method to enlarge the area of absorber in NIS type superconductor radiation detectors.In 2002, we invented three methods to improve the energy resolution of NIS detector, employing SQUIDs: (1) Asymmetrically Modulated SQUIDs, (2) Josephson Junction Microcalorimeter with Superconductor Loop, and (3) Rf-SQUID Microcalorimeter. These detectors have Josephson junctions coupled with normal metal absorber. The energy of radiation is measured by a SQUID as the change of critical current of the Josephson junction due to the increase of electron temperature. The energy resolutions of 1.5eV to 5.8eV are expected by these three methods at the operating temperature of 1O0mK.