The University of Tokyo · Physics and Astronomy
Professor Tadayuki Takahashi's research lab specializes in high-energy astrophysics, focusing on the development of advanced X-ray and gamma-ray detectors for space-based observatories. The lab's main research directions include the design and optimization of semiconductor detectors such as CdTe and CdZnTe for improved energy resolution and efficiency in hard X-ray and gamma-ray astronomy. They also contribute significantly to mission development, particularly in instrumentation for X-ray space telescopes like Suzaku and ASTRO-H, emphasizing low-background detection techniques and high-throughput spectroscopy across a broad energy range. Their work bridges materials science, detector physics, and observational astrophysics to explore energetic phenomena in the universe, such as active galactic nuclei and flaring sources like BL Lac objects.
Figures are computed from collected data and may differ slightly.
Abstract The Hard X-ray Detector (HXD) on board Suzaku covers a wide energy range from 10 keV to 600 keV by the combination of silicon PIN diodes and GSO scintillators. The HXD is designed to achieve an extremely low in-orbit background based on a combination of new techniques, including the concept of a well-type active shield counter. With an effective area of $142 \,\mathrm{cm}^{2}$ at 20 keV and $273 \,\mathrm{cm}^{2}$ at 150 keV, the background level at sea level reached $\sim 1 \times 10^{
Cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) have been regarded as promising semiconductor materials for hard X-ray and /spl gamma/-ray detection. The high atomic number of the materials (Z/sub Cd/=48, Z/sub Te/=52) gives a high quantum efficiency in comparison with Si. The large bandgap energy (Eg/spl sim/1.5 eV) allows us to operate the detector at room temperature. However, a considerable amount of charge loss in these detectors produces a reduced energy resolution. This probl
We observed the BL Lac object Mrk 421 with the X-ray satellite ASCA in 1994 as part of a multifrequency observation. The 24 hr observation was conducted 1 day after the onset of a TeV flare detected by the Whipple Observatory and detected an X-ray flare, with no apparent variability in the optical, UV, and EGRET GeV flux. The ASCA 2-10 keV flux peaked at 3.7 × 10-10 ergs cm-2 s-1 and then decreased to 1.8 × 10-10 ergs cm-2 s-1 with a doubling timescale of ~12 hr. The shape of the X-ray spectrum
The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe by performing high-resolution, high-throughput spectroscopy with moderate angular resolution. ASTRO-H covers very wide energy range from 0.3 keV to 600 keV. ASTRO-H allows a combination of wide band X-ray spectroscopy (5-80 keV) provided by multilayer coating, focusin
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