X-ray Detection Performance of 100-pixel Superconducting Tunnel Junction Array Detector in the Soft X-ray Region

Abstract

The overall performance of a 100-pixel superconducting tunnel junction (STJ) array detector in the soft X-ray region was determined by measuring fluorescent X-rays from light elements. The yield of working STJs in the fabricated detector was 90%, and the leakage current for these 90 STJs was 11.6 ± 2.5 nA. The STJs had an intrinsic energy resolution for O-Kα X-rays (524.9 eV) of 10.2 ± 1.7 eV (FWHM). The deviation from energy linearity was −0.042 ± 0.45%, 0.793 ± 0.91%, and 0.135 ± 1.31% for O-Kα (524.9 eV), N-Kα (392.4 eV) and B-Kα (183.3 eV) Xrays, respectively. Most of the STJs exhibited uniform X-ray detection characteristics. In addition, the detector could discriminate the N-Kα peak in the fluorescent X-ray spectrum from n-type SiC doped with 300 ppm nitrogen.

Review of superconducting transition-edge sensors for x-ray and gamma-ray spectroscopy

“…However, the energy resolution of cryogenic sensors allows elemental x-rays excited by the primary beam to be unambiguously counted in the presence of x-rays from other elements and from the scattered excitation beam. Measurements of this type have been successfully performed with both STJs and TESs [184][185][186].…”

Characteristics of Nb/Al superconducting tunnel junctions fabricated using ozone gas

“…The x-ray signals from the STJ array were processed using 100-channel charge-sensitive amplifiers and 100-channel FPGA-DSP based multi-channel analyzers. [12] 3. Result and discussion 2.…”

High-resolution X-ray emission spectroscopy with transition-edge sensors: present performance and future potential

“…Another type of low-temperature detector, the superconducting tunnel junction (STJ), has been used previously for beamline science (Lordi et al, 2003;Shiki et al, 2012). Like a SDD, the resolution of an individual STJ is limited by Fano statistics in the creation of excitations, and scales as the square root of the energy of the absorbed photon.…”

“…The purpose of this paper is not a comprehensive comparison of detector technologies but we briefly comment on the energy resolution of STJs. At 400 eV, resolution as good as 2.45 eV FWHM has been demonstrated although values of 5-10 eV are more common (Verhoeve et al, 2010;Carpenter et al, 2013;Shiki et al, 2012). Achieving good resolution at energies above 1 keV has proven difficult for STJs due to a variety of factors.…”