Bismuth X-ray absorber studies for TES microcalorimeters

J. E. Sadleir*, S. R. Bandler, R. P. Brekosky, J. Chervenak, E. Figueroa-Feliciano, F. Finkbeiner, N. Iyomoto, R. L. Kelley, C. A. Kilbourne, J. M. King, F. S. Porter, I. K. Robinson, T. Saab, D. J. Talley

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Bismuth's large atomic number and low carrier density makes it an attractive X-ray absorber material for microcalorimeters. Bismuth's long fermi wavelength and long mean free paths have motivated much interest in the fabrication of high quality bismuth films to study quantum size effects. Despite such incentives, fabrication of high quality bismuth films has proven difficult, and measured properties of such films are highly variable in the literature. Implementing a bismuth deposition process for TES (superconducting Transition Edge Sensor) device fabrication presents additional challenges particularly at interfaces due to the inherent granularity and surface roughness of its films, its low melting point, and its tendency to diffuse and form undesired intermetallic phases. We report observations of Bi-Cu and Bi-Au diffusion in our devices correlating with large shifts in Tc (superconducting transition temperature). Using SEM and in situ R vs T annealing experiments we have been able to study these diffusion processes and identify their activation temperatures.

Original languageEnglish (US)
Pages (from-to)447-449
Number of pages3
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume559
Issue number2
DOIs
StatePublished - Apr 14 2006

Keywords

  • Diffusion
  • In situ resistance annealing
  • Microcalorimetry
  • Multilayer strip resistance
  • Superconducting transition edge sensor (TES)
  • X-ray absorber

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation

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