Development of the hard x-ray monitor onboard WF-MAXI

Makoto Arimoto*, Yoichi Yatsu, Nobuyuki Kawai, Hirokazu Ikeda, Atsushi Harayama, Shin'Ichiro Takeda, Tadayuki Takahashi, Hiroshi Tomida, Shiro Ueno, Masashi Kimura, Tatehiro Mihara, Motoko Serino, Hiroshi Tsunemi, Atsumasa Yoshida, Takanori Sakamoto, Tadayoshi Kohmura, Hitoshi Negoro, Yoshihiro Ueda

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)


WF-MAXI is a mission to detect and localize X-ray transients with short-term variability as gravitational-wave (GW) candidates including gamma-ray bursts, supernovae etc. We are planning on starting observations by WF-MAXI to be ready for the initial operation of the next generation GW telescopes (e.g., KAGRA, Advanced LIGO etc.). WF-MAXI consists of two main instruments, Soft X-ray Large Solid Angle Camera (SLC) and Hard X-ray Monitor (HXM) which totally cover 0.7 keV to 1 MeV band. HXM is a multi-channel array of crystal scintillators coupled with APDs observing photons in the hard X-ray band with an effective area of above 100 cm2. We have developed an analog application specific integrated circuit (ASIC) dedicated for the readout of 32-channel APDs' signals using 0.35 μm CMOS technology based on Open IP project and an analog amplifier was designed to achieve a low-noise readout. The developed ASIC showed a low-noise performance of 2080 e- + 2.3 e-/pF at root mean square and with a reverse-type APD coupled to a Ce:GAGG crystal a good FWHM energy resolution of 6.9% for 662 keV -rays.

Original languageEnglish
Title of host publicationSpace Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray
ISBN (Electronic)9780819496126
Publication statusPublished - 2014
Externally publishedYes
EventSpace Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray - Montreal
Duration: 2014 Jun 222014 Jun 26


OtherSpace Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray


  • APD
  • ASIC
  • low noise
  • X-ray detectors

ASJC Scopus subject areas

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


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