Present performance of a single pixel Ti/Au bilayer TES calorimeter

Yoshitaka Ishisaki, Umeyo Morita, Takeo Koga, Kosuke Sato, Takaya Ohashi, Kazuhisa Mitsuda, Noriko Y. Yamasaki, Ryuichi Fujimoto, Naoko Iyomoto, Tai Oshima, Kazuo Futamoto, Yoh Takei, Taro Ichitsubo, Tamayuki Fujimori, Shuichi Shoji, Hiroyuki Kudo, Tomoaki Nakamura, Takahiro Arakawa, Tetsuya Osaka, Takayuki HommaHirotaka Sato, Hideomi Kobayashi, Kentaro Mori, Keiichi Tanaka, Toshimitsu Morooka, Satoshi Nakayama, Kazuo Chinone, Yoshikatsu Kuroda, Mitsunobu Onishi, Kunio Otake

Research output: Contribution to journalConference articlepeer-review

8 Citations (Scopus)


We are developing a superconducting transition-edge sensor (TES) calorimeter for future Japanese X-ray astronomy missions (e.g. NeXT mission). The performance of our single pixel TES calorimeter is presented. We fabricated a Ti/Au (40 nm/110 nm) bilayer TES on a thin silicon-nitride membrane, which is adjusted to have a transition temperature of about 100 mK. The size of the TES is 500 μm × 500 μm, and 300 μm × 300 μm gold with a thickness of 300 nm is deposited with sputtering as an X-ray absorber. The TES calorimeter was installed in a dilution refrigerator operated at ∼ 40 mK, with a combination of 400-series SQUID array as an ammeter. Collimated 5.9 keV X-rays (200 μm in diameter) from 55Fe isotope were irradiated and X-ray pulses were obtained. Simultaneously with a fast falling time constant of 74.2 μs, the energy resolution of 6.6 ± 0.4 eV was attained, while the baseline noise was 6.4 eV. The contents of the energy resolution are 5.1 eV of the excess noise, 3.3 eV of the readout noise, 1.6 eV of the pulse by pulse variation, and 1.9 eV of the intrinsic noise. The baseline noise are dominated by an unknown excess noise, which increases roughly in proportion to the inverse of the TES resistance. The pulse height is sensitive to the operating conditions, and the superconducting shield appears to have improved it by a factor of ∼ 2. The calorimeter works fine over six months surviving five thermal cycles, even though it is kept in air.

Original languageEnglish
Pages (from-to)831-841
Number of pages11
JournalProceedings of SPIE - The International Society for Optical Engineering
Issue number2
Publication statusPublished - 2002
Externally publishedYes
EventX-Ray and Gamma-Ray Telescopes and Instruments for Astronomy - Waikoloa, HI, United States
Duration: Aug 24 2002Aug 28 2002

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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