TY - GEN
T1 - Current status of the pre-collimator development for the ASTRO-H X-ray Telescopes
AU - Mori, Hideyuki
AU - Haba, Yoshito
AU - Miyazawa, Takuya
AU - Furuzawa, Akihiro
AU - Tawara, Yuzuru
AU - Kunieda, Hideyo
AU - Yamauchi, Shigeo
AU - Awaki, Hisamitsu
AU - Ishida, Manabu
AU - Maeda, Yoshitomo
AU - Bamba, Aya
AU - Iizuka, Ryo
AU - Okajima, Takashi
AU - Mushotzky, Richard
PY - 2010/10/19
Y1 - 2010/10/19
N2 - We present the current status of the pre-collimator for the stray-light reduction, mounted on the ASTRO-H X-Ray Telescopes (XRT). Since the ASTRO-H XRTs adopt the conical approximation of the Wolter-I type grazing incident optics, X-rays from a source located far from the telescope boresight create a ghost image in the detector field of view (FOV) as a stray light, and then reduce the signal-to-noise ratio even in the hard X-ray band. We thus plan to mount the pre-collimator, which is comprised of cylindrical blades aligned with each primary mirror, onto the XRTs to remove the stray light. While the pre-collimator for the Soft X-ray Telescopes is designed by the similar principle adopted for the Suzaku pre-collimator, that for the Hard X-ray Telescopes requires some trade-off studies to select an appropriate blade material. The HXT pre-collimator currently utilizes the aluminum blade with the 50 mm height and 150 μm thickness. We examined the observational effects by the hard X-ray (> 10 keV) stray light and the expected performance of the pre-collimator in some scientific cases, using a ray-tracing simulator. We found that the Galactic center may be mostly covered with the stray light from the well-known bright X-ray sources. In addition, the flux estimation of the extended X-ray emission such as the Cosmic X-ray Background is also found to have large (∼ 30%) uncertainty due to the stray light from the outside of the XRT FOV. The pre-collimator improves the situations; the stray light covering the source-free region in the Galactic center can be reduced by half and the uncertainty of the flux determination for the diffuse source decreases down to < 10%.
AB - We present the current status of the pre-collimator for the stray-light reduction, mounted on the ASTRO-H X-Ray Telescopes (XRT). Since the ASTRO-H XRTs adopt the conical approximation of the Wolter-I type grazing incident optics, X-rays from a source located far from the telescope boresight create a ghost image in the detector field of view (FOV) as a stray light, and then reduce the signal-to-noise ratio even in the hard X-ray band. We thus plan to mount the pre-collimator, which is comprised of cylindrical blades aligned with each primary mirror, onto the XRTs to remove the stray light. While the pre-collimator for the Soft X-ray Telescopes is designed by the similar principle adopted for the Suzaku pre-collimator, that for the Hard X-ray Telescopes requires some trade-off studies to select an appropriate blade material. The HXT pre-collimator currently utilizes the aluminum blade with the 50 mm height and 150 μm thickness. We examined the observational effects by the hard X-ray (> 10 keV) stray light and the expected performance of the pre-collimator in some scientific cases, using a ray-tracing simulator. We found that the Galactic center may be mostly covered with the stray light from the well-known bright X-ray sources. In addition, the flux estimation of the extended X-ray emission such as the Cosmic X-ray Background is also found to have large (∼ 30%) uncertainty due to the stray light from the outside of the XRT FOV. The pre-collimator improves the situations; the stray light covering the source-free region in the Galactic center can be reduced by half and the uncertainty of the flux determination for the diffuse source decreases down to < 10%.
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U2 - 10.1117/12.856803
DO - 10.1117/12.856803
M3 - Conference contribution
AN - SCOPUS:77957857562
SN - 9780819482228
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Space Telescopes and Instrumentation 2010
T2 - Space Telescopes and Instrumentation 2010: Ultraviolet to Gamma Ray
Y2 - 28 June 2010 through 2 July 2010
ER -