Characterization of High Aspect-Ratio TiAu TES X-ray Microcalorimeter Array Under AC Bias

E. Taralli, L. Gottardi, K. Nagayoshi, M. Ridder, S. Visser, P. Khosropanah, H. Akamatsu, J. van der Kuur, M. Bruijn, J. R. Gao

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)


We are developing X-ray microcalorimeters as a backup option for the baseline detectors in the X-IFU instrument on board the ATHENA space mission led by ESA and to be launched in the early 2030s. 5 × 5 mixed arrays with TiAu transition-edge sensor (TES), which have different high aspect ratios and thus high resistances, have been designed and fabricated to meet the energy resolution requirement of the X-IFU instrument. Such arrays can also be used to optimize the performance of the frequency domain multiplexing (FDM) readout and lead to the final steps for the fabrication of a large detector array. In this work, we present the experimental results from tens of the devices with an aspect ratio (length-to-width) ranging from 1-to-1 up to 6-to-1, measured in a single-pixel mode with a FDM readout system developed at SRON/VTT. We observed a nominal energy resolution of about 2.5 eV at 5.9 keV at bias frequencies ranging from 1 to 5 MHz. These detectors are proving to be the best TES microcalorimeters ever reported in Europe, intending to meet the requirements of the X-IFU instrument, but also those of other future challenging X-ray space missions, fundamental physics experiments, plasma characterization and material analysis.

Original languageEnglish
Number of pages9
JournalJournal of Low Temperature Physics
Publication statusPublished - 2019


  • AC bias
  • Energy resolution
  • Transition-edge sensor
  • X-IFU

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