Development of X-ray detection system by using an on-chip coil inetgrated superconducting tunnel junction

使用片上线圈集成超导隧道结的X射线检测系统的开发

基本信息

批准号：
12558056
负责人：
MAEHATA Keisuke
金额：
$ 7.68万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

An on-chip coil integrated superconducting tunnel junction (OC^2-STJ) was developed for high performance X-ray detector. The OC^2-STJ consists of a Nb-based junction and a superconducting microstrip coil deposited on the insulating layer deposited on the top electrode of the STJ. The microstrip coil generates the magnetic field in the insulating layer of the junction for suppression of Josephson current. The fabricated OC^2-STJ chip was mounted in a cooling capsule with the ^<55>Fe X-ray source. The cooling capsule was attached to the mixing chamber of a compact ^3He-^4He dilution refrigerator. The OC^2-STJ chip was held at a constant temperature in the capsule against the Joule heat generation in the current feed line of the strip coil during the detector operation. Electric charges produced by tunneling of excited quasiparticles by incident X-rays were collected by a charge sensitive preamplifier. To reduce noise components in the output signals, a field effect transistor (FET) of the signal input was placed on the 1 K pot of the refrigerator through a weak thermal link. The temperature of the input FET was regulated at 100 K by a heater to generate the output voltage pulses with the minimum noise equivalent charge. The temperature of the OC^2-STJ chip was kept around 600 mK with regulating the FET temperature at 1 K. In the operation of the OC^2-STJ for X-ray detection, the current from 10 to 30 mA was supplied to the microstrip coil. Response characteristics were obtained for a diamond-shaped Nb-based tunnel junction with a sensitive area of 100 × 100 μm^2 in the OC^2-STJ chip. A stable operation of the OC^2-STJ was demonstrated without using usual external electromagnets.

为高性能X射线检测器开发了片上线圈集成的超导隧道连接（OC^2-STJ）。 OC^2-STJ由基于NB的连接和一个沉积在STJ顶部电极上的绝缘层上的超导微带线圈组成。微带线圈在连接处的绝缘层中生成磁场，以抑制约瑟夫森电流。用 ^<55> fe X射线源将制造的OC ^2-STJ芯片安装在冷却胶囊中。冷却胶囊连接到紧凑型 ^3he- ^4he稀释冰箱的混合室。 OC^2-STJ芯片在检测器操作过程中在胶囊的当前进料线中与焦耳热产生的固定温度保持在恒定温度下。通过电荷敏感的前置放大器收集了通过入射X射线对激发的准颗粒产生的电荷。为了减少输出信号中的噪声组件，将信号输入的场效应晶体管（FET）放在冰箱的1 K锅上，通过弱热链接。输入FET的温度通过加热器在100 K下调节，以产生输出电压脉冲，并具有最小的噪声等效电荷。 OC^2-STJ芯片的温度保持在600 mk左右，在1 K处调节FET温度。在OC^2-STJ进行X射线检测的运行中，将电流从10到30 mA提供给微带线圈。在OC^2-STJ芯片中，获得了钻石形的基于NB的隧道连接的响应特征，其敏感面积为100×100μm^2。在不使用通常的外部电子磁铁的情况下，证明了OC^2-STJ的稳定操作。