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

• Published in: Journal of low temperature physics 2020-04, Vol.199 (1-2), p.80-87
• Main Authors: Taralli, E., Gottardi, L., Nagayoshi, K., Ridder, M., Visser, S., Khosropanah, P., Akamatsu, H., van der Kuur, J., Bruijn, M., Gao, J. R.
• Format: Article
• Language: English
• Subjects: Bias; Calorimeters; Characterization and Evaluation of Materials; Condensed Matter Physics; Detectors; Energy resolution; Frequency division multiplexing; High aspect ratio; Low temperature physics; Magnetic Materials; Magnetism; Physics; Physics and Astronomy; Plasmas (physics); Sensor arrays; Space missions
• ISSN: 0022-2291; 1573-7357
• DOI: 10.1007/s10909-019-02254-y

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.