High-resolution superconducting X-ray spectrometers with an active area of 282 μm×282 μm

Abstract

Superconducting tunnel junctions coupled to superconducting absorbers may be used as high-resolution, high-efficiency X-ray s p e ctrometers. We have tested devices with niobium Xray absorbing layers coupled to aluminum layers that serve as quasiparticle traps. In this work we measure the current pulses from a large-area tunnel junction using an amplifier based on an array of 100 SQUIDS. Using this amplifier and a 282 ym x 2 8 2 ym junction, we have measured an energy resolution of 19 eV FWHM for 1.5 keV X rays and 21 eV for 2.6 keV X rays. The area of this junction is eight t i m e s the area of any junction previously measured t o have such high energy resolution.

Development of a compact system for high-resolution X-ray detection using a SQUID amplifier

“…The resistance Rb is used for biasing to the STJ and R, is used as a shunt for RF filtering [3]- [5]. The STJ has a dynamic resistance Rd of 100 kS1 and a capacitance C of 400 pF.…”

Array of Superconducting Quantum Interference Devices with Multiturn Input Coil

“…B is the angular frequency bandwidth, which is required for a measurement system (2%f B ) to measure signals. Equation (2) shows that I in ðmaxÞ decreases with increasing M in . The maximum feedback flux of the FLL circuit È f ðmaxÞ is…”

“…1) Recently, an X-ray spectroscopy system that uses superconducting technologies has attracted much interests. 2,3) Cryogenic detectors are based on superconducting tunnel junctions (STJs) and superconducting transition edge sensors (TESs). They have been developed for next-generation X-ray microanalysis in the semiconductor industry and material science, 4) and for X-ray astronomy.…”

Imaging of vortices in superconductors by electron beam scanning

“…1,2 Recently, superconducting tunnel junctions ͑STJ's͒ have attracted strong attention because of their application potential as particle and radiation detectors with high energy resolution. [3][4][5][6][7] Here the quasiparticles generated in the electrodes of the junction are detected by means of the tunneling conductivity. Simulating the irradiation event by electron beam scanning has provided useful information on the quasiparticle dynamics and for optimizing the performance of superconducting tunnel junction detectors, 8 because of the high spatial and temporal resolution achieved by this method.…”