High-performance superconducting-tunnel-junction X-ray detector with resonant reading function

超导隧道结X射线检测器期望具有宽的有效面积以用于实际应用。我们尝试研究共振偏压和隧道结的阅读方法，以改善X射线探测的性能。因此，从超导体高频相位差混合（交流约瑟夫森效应）的角度研究了它们的电流-电压特性。结果表明，当结工作在高阻抗偏置下时，高频相位差的行为往往导致非线性直流漏电流。由于利用电感（L）和电容（C）的谐振方法产生低阻抗情况，期望提供更稳定的操作。6 keV X射线的实验电子分辨率为800 eV，在传统的房间和240 eV的电磁屏蔽条件。240 eV的值是理想预期分辨率的一个数量级。结果表明，完整的电磁屏蔽环境对获得理想的良好性能至关重要。

Superconducting tunnel junction x-ray detectors are desired to have a wide active area for practical use. We attempt to study the usefulness of resonant biasing and reading method for tunnel junctions, for improving the performance in x-ray detection.It is know that large-area tunnel junctions are not completely stable in current-voltage characteristics. The current-voltage characteristics are, therefore, investigated to understand their behavior from the viewpoint of mixture of high frequency phase- difference of superconductors (ac Josephson effect). It was made clear that behavior of high frequency phase difference tends to lead to non-linear dc leakage current, when junctions are operated in high impedance biasing. Since the resonant method making use of inductance (L) and capacitance (C) produces low impedance situation, it is expected to give more stable operation.Experiments with LC biasing and reading were carried out. The experimental electronic resolution for 6-keV x-rays was 800 eV at a conventional room and 240 eV at an electromagnetical shielded condition. The value of 240eV was one order in magnitude as high as the resolution ideally expected. It was concluded that the complete electromagnetical shielding circumstance is essential important to obtain the ideal good performance.