Development of position-sensitive transition-edge sensor X-ray detectors

Stephen James Smith, Simon R. Bandler, Regis P. Brekosky, Ari David Brown, Jay A. Chervenak, Megan E. Eckart, Encetali Figueroa-Feliciano, Fred M. Finkbeiner, Richard L. Kelley, Caroline A. Kilbourne, Frederick Scott Porter, John E. Sadleir

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


We report on the development of position-sensitive transition-edge sensors (PoST's) for future X-ray astronomy missions such as the International X-ray Observatory (IXO), under study by NASA and ESA. PoST's consist of multiple absorbers each with a different thermal coupling to one or more transition-edge sensors (TESs). This results in a characteristic pulse shape for each absorber element and allows position discrimination. PoST development is motivated by a desire to achieve maximum focal-plane area with the fewest number of readout channels. We report detailed characterization of our single TES PoST's or Hydras, which consist of four electroplated Au/Bi absorbers coupled to a low noise Mo/Au TES. Using a numerical model of the Hydra we fit to measured complex impedance curves and determine device parameters that allow us to accurately reproduce the measured pulse shapes and noise spectra. Results from Hydras with different internal thermal conductances reveal the trade-offs in optimizing for energy resolution or position-sensitivity. We report a best achievable energy resolution of <6.0 eV across all pixels for a device with transition temperature of 86 mK, coupled with straightforward position discrimination by rise-time.

Original languageEnglish (US)
Article number5075616
Pages (from-to)451-455
Number of pages5
JournalIEEE Transactions on Applied Superconductivity
Issue number3
StatePublished - Jun 2009


  • Hydra
  • Microcalorimeter
  • Position-sensitive detector
  • Transition-edge sensor

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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