During the Hitomi (Astro-H) commissioning observations the SXS dewar gate valve (GV) remained closed to protect the instrument from initial spacecraft outgassing. As a result, the optical path of the observations included the Be window installed on the GV. Both x-ray fluorescence (XRF) analysis and x-ray transmission measurements were performed in June 2016 on the flight-spare Be window which is the same lot as the flight material at SPring-8 in Japan. The beamline operating range is 3.8 - 30 keV. We used a beam spot size of 1 mm × 0.2 mm to measure two positions on the Be window, at the center of the window and at one position 6.5 mm off-center. We used simultaneous transmission measurements of standard materials for energy calibration. The transmission data clearly showed Fe and Ni K-edges, plus a marginal detection of the Mn K-edge. We found that our transmission data was best fit using the following component Be: 261.86±0.01μm, Cr: 3nm (fixed), Mn: 3.81±0.05nm, Fe: 10.83±0.05nm, Ni: 16.48±0.03nm, Cu: 5nm (fixed). The transmission is reduced 1% at the Fe K-edge. The amount of contaminated materials are comparable to the values of the value provided by the vender. The surface transmission is strained with σ = 0.11% of the unbiased standard deviation calculated variation in the residuals between the measured value and the model.
The Soft X-ray Spectrometer (SXS) onboard the Hitomi (ASTRO-H) satellite observed several celestial objects. All the observations with the SXS were performed through a beryllium (Be) window installed on the gate-valve of the SXS dewar. However, the Be window had not been well calibrated before launching. Therefore, we measured the transmission of a spare Be window, which is from the same lot as the flight material. The measurements were preformed in 3.8–30 keV range with BL01B1 at SPring-8, and in 2.5–12 keV range combined with BL11B and BL7C at KEK-PF. In this paper, we report mainly the results of the KEK-PF experiment. With the KEK-PF, we measured five places of the Be window. Their estimated thicknesses are consistent with each other within 1.3 μm. In the five transmission data, we confirmed absorption edges by Fe-K, Ni-K and Mn-K and six edge like features at 3460, 6057, 6915, 7590, 8790 and 9193 eV, which can be interpreted as Bragg diffraction by Be polycrystal. By combining the transmissions measured at KEK-PF and at SPring-8, we estimated Be thickness of 259.73±0.01 μm. The amounts of contaminated materials are roughly comparable with the provided values from the provider. We also performed scanning measurements of whole surface in the Be window. In the results, thickness of Be window was found to be uniform in ±1µm from the measurement with 4 keV X-rays.
We report recent results of the performance measurement of our X-ray telescope with adaptive optics. The
telescope is designed to use the 13.5nm EUV with the Mo/Si multilayers, making a normal incident optics. The
primary mirror is 80mm in its diameter and the focal length of 2m. The deformable mirror is controlled by
measuring a wave-front of an optical laser. Effects of a difference between the light paths from the reference and
from an object are examined. The angular resolution is measured with optical light and we confirm almost
diffraction limited resolution as well as its appropriate function as adaptive optics.