A superconducting tunnel junction x-ray detector with performance limited by statistical effects

Journal Article · Sat Aug 01 04:00:00 EDT 1998 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.122372· OSTI ID:641502

le Grand, J B; Mears, C A; Hiller, L J; Frank, M; Labov, S E; Netel, H; Chow, D; Friedrich, S; Lindeman, M A ^[1]; Barfknecht, A T ^[2]

---

1. Lawrence Livermore National Laboratory, P.O. Box 808, L-418, Livermore, California 94550 (United States)
2. Conductus, Inc., 969 West Maude Avenue, Sunnyvale, California 94086 (United States)

We have characterized a thin-film Nb/Al/AlO{sub x}/Al/Nb superconducting tunnel junction (STJ) optimized for low electronic noise as an x-ray detector in the 0.2{endash}1 keV photon energy range. The spectra measured with this junction have high spectral purity with, to the best of our knowledge, the best energy resolution ever achieved with this type of detector in this energy band. The discrepancy between the theoretical and experimental energy resolution is only about 15{percent}. Part of this small discrepancy may be explained by the fact that our junction has electrodes made from niobium/aluminum bilayers, while the theoretical result is for electrodes made from only one material. To the best of our knowledge, this is the first time that resolution achieved with a STJ x-ray detector is in agreement with the resolution predicted from statistical fluctuations in the creation and tunneling of quasiparticles. {copyright} {ital 1998 American Institute of Physics.}

• OSTI ID: 641502
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 9 Vol. 73; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
66 PHYSICS
ALUMINIUM OXIDES
DESIGN
KEV RANGE 01-10
NIOBIUM
SIGNAL-TO-NOISE RATIO
SUPERCONDUCTING JUNCTIONS
X-RAY DETECTION