Performance of HXD on ASTROE1

1
K. Makishima1, T. Takahashi2, T. Murakami2,
T. Kamae3, Y. Fukazawa3, M. Tashiro4, and
the HXD team1-71 University of Tokyo 2 ISAS 3
Hiroshima University4 Saitama University 5
Osaka University 6KEK 7RIKEN
The Hard X-ray Detector ( HXD-II ) on
ASTRO-E II
HXD Hardware

• Performance of HXD on ASTRO-E1

ASTRO-E

• HXD-S (sensor) , weighing 200 kg
• ? 16 Well-type counter units in a 44
  coumpound-eye configuration
• - GSO and BGO crystals in phoswich coupling
  (30-600 keV)
• - 2 mm thick silicon PIN diodes (10 - 50 keV)
• - Active plus passive collimation of the field
  of view
• ? 20 Anti Counters, made of thick BGO,
  surrounding the Well-type units
• HXD-AE (analog electronics)
• ? 100 channels of parallel processing, tolerant
  to very high counting rates
• ? Precaution against events with very large
  energy deposits
• ? Flexible anti-coincidence logic
• ? Sophisticated architecture employing
  semi-custom VLSI and FPGA
• HXD-DE (digital electronics)
• ? DMA to reduce the CPU load
• ? Software for both the data/command protocol
  and the event selection

The measured GOS responses to various ?-ray
isotopes.
HXD-S

• Scientific objectives High-sensitivity and
  Wide-band study of ..
• Particle Acceleration in Stars, SNRs,
  Interstellar Space, Blazars, Radio Galaxies, and
  Clusters of Galaxies
• Nuclear lines (44Ti etc.)
• The ee- annihilation lines
• X-ray to ?-ray continua of Black Hole Binaries
  and AGNs
• Cyclotron lines in Accreting X-ray
  Pulsars
• Rotation powered pulsars
• The CXB above 20 keV
• and so on..

The expected sensitivities of various hard X-ray
experiments.
The PIN (left) and GOS (right) room background
spectrum measured at -20? during the spacecraft
thermal-vacuum test.
The completed HXD-S
Seven Well-type counter units being assembled
A single unit of Well-type phoswich counter
Possible improvements presently investigated

• HXD-S
• 1. Increasing the effective area of the PIN
  diodes by
• adjusting the electrode design.
• 2. Increasing the quantum efficiency of the PMT
• (23 ? 30).
• 3. Further evaluation of the low-level
  radioisotope
• contamination in detector materials.
• 4. Possible replacement of the PIN diodes with
  CdTe
• (20mm square, 0.5mm thick), having a much
  higher
• QE and probably a better ?E.

• HXD-AE
• 1. No major changes in the architecture.
• 2. Improving the grounding design.
• 3. Possible increase in the mechanical height.
• HXD-DE
• 1. No major hardware/software design changes.
• 2. Some software improvements.