Masahiro Tsujimoto

one of the instruments on the Advanced Telescope for High-Energy Astrophysics (Athena) which was one of the three missions under study as one of the L-class missions of ESA, is the X-ray Microcalorimeter Spectrometer (XMS). This instrument, which will provide high-spectral resolution images, is based on X-ray micro-calorimeters with Transition Edge Sensor (TES) and absorbers that consist of metal and semi-metal layers and a multiplexed SQUID readout. The array (32 x 32 pixels) provides an energy resolution of < 3 eV. Due to the large collection area of the Athena optics, the XMS instrument must be capable of processing high counting rates, while maintaining the spectral resolution and a low deadtime. In addition, an anti-coincidence detector is required to suppress the particle-induced background. Compared to the requirements for the same instrument on IXO, the performance requirements have been relaxed to fit into the much more restricted boundary conditions of Athena. In this paper we illustrate some of the science achievable with the instrument. We describe the results of design studies for the focal plane assembly and the cooling systems. Also, the system and its required spacecraft resources will be given. © 2012 SPIE.

We present the development status of the Pulse Shape Processor (PSP), which is the on-board digital electronics responsible for the signal processing of the X-ray microcalorimeter spectrometer instrument (the Soft X-ray Spectrometer; SXS) for the ASTRO-H satellite planned to be launched in 2014. We finished the design and fabrication for the engineering model, and are currently undertaking a series of performance verification and environmental tests. In this report, we summarize the results obtained in a part of the tests completed in the first half of this year. © 2012 SPIE.

The 3rd Suzaku international Conference "Energetic Cosmos : from Suzaku to ASTRO-H" (June 29-July 2, 2009. Grand Park Otaru Hotel), Otaru, Hokkaido JapanWe report current status of the timing calibration of the X-ray Imaging Spectrometer (XIS) on board Suzaku. The XIS is designed to be flexible enough and can be operated in various clocking modes. Since the absolute timing accuracy of the Hard X-ray Detector (HXD) was calibrated to be better than 360 microseconds, we calibrated the XIS timing accuracy referring to the HXD data. We employed Hercules X-1 and Cygnus X-1 for the calibration taking into account of the energy dependence of their time variations. We found no significant offset in the XIS time assignment in the normal mode (with burst/window options), whereas a marginal offset of 30 +/- 16 ms was found in the Parallel-Sum mode.Meeting sponsors: The University of Tokyo, The Institute of Physical and Chemical Research, The Japan Society for the Promotion of Science

The 3rd Suzaku international Conference "Energetic Cosmos : from Suzaku to ASTRO-H" (June 29-July 2, 2009. Grand Park Otaru Hotel), Otaru, Hokkaido JapanWe report the XIS calibration on the data taken with the 2 x 2 mode and window option and the current status of the XIS Non-X-ray Background (NXB) database. The 2 x 2 mode and window option are useful for bright source observations to avoid telemetry saturation and event pile-up. The NXB database provides the best-estimated NXB spectrum for any specific observations obtained with the standard mode (Normal-Clock with no Window or Burst and 5 x 5(sub -) (3 x 3(sub -) Editing mode). The data taken with the 2 x 2 mode in the "SCI-off" era are fully calibrated, and there is no practical difference from those taken with the standard mode. A calibration study for the data taken with the 2 x 2 mode in the "SCI-on" era is on-going. The calibration for the data taken with the window option was significantly improved in the HEASOFT 6.6.2 released at 2009 April 1st. In the comparison with the standard-mode data, the gain difference around 6 keV becomes less than 10 and 15 eV in XIS 0,3 and XIS 1, respectively. We have been updating the NXB database every half a year. There is no drastic change in the light curves, but steady approximately 4 % year(sup -1) level increase and decrease are found in those of XIS 0,3 and XIS 1, respectively.Meeting sponsors: The University of Tokyo, The Institute of Physical and Chemical Research, The Japan Society for the Promotion of ScienceNumber of authors: 25

A digital signal processing system for the X-ray microcalorimeter array (SXS) is being developed for the next Japanese X-ray astronomy satellite, ASTRO-H. The SXS digital signal processing system evaluates each pulse by an optimal filtering process. For the ASTRO-H project, we decided to employ digital electronics hardware, which includes a digital I/O board based upon FPGAs, and a separate CPU board. It is crucially important for the FPGA to be able to detect the presence of an "secondary" pulses on the tail of an initial pulse. In order to detect the contaminating pulses, we have developed a new finite impulse response filter, to compensate for the undershoot in the derivative. By employing the filter it is possible for FPGA to detect the secondary pulse very close the first pulse, and to reduce the load of the CPU in the secondary pulse searching process. © 2009 American Institute of Physics.

Protostars, the first stage of stellar evolution, are born in a dense core of a molecular cloud with temperature of about 10 K. X-rays can be emitted from a high temperature plasma of 10^6-10^8K, hence may not be expected from protostars. Nature, however, is much more imaginative than we are. The Japanese X-ray satellite ASCA found X-rays from a few protostars. The US satellite Chandra successively found that X-rays are common in most of the young stars. Many protostars show flare-like events similar to our sun, hence the X-rays are attributable to solar type magnetic activities. The X-ray work should finally lead to our deep understanding of the evolution and structure of young stars and planets. This paper overviews the pioneering results in the unique waveband, the X-ray.

We study the relation between diffusion and loss of charge produced in X-ray CCDs with the fitting method. We obtain the extent and the pulse height of each X-ray event in a CCD by a two-dimensional image-fitting the charge distribution of the event. For the monochromatic X-rays, we find that the event with small extent keeps all the charge produced, while that with larger extent than a certain value loses some part of the produced charge as a function of extent. The result suggests that the event with a small extent is produced by an X-ray absorbed in the depletion layer. On the other hand, the event with large extent corresponds to an X-ray absorbed in the field-free region. We develop two new methods which enable us to derive the relation between the extent of an event and the absorption depth. One is performed by illuminating well calibrated monochromatic X-ray source. The other is realized by using with two monochromatic X-rays and enables us to measure the thickness of the CCD depletion layer without calibrating absolute flux of the monochromatic X-rays.

CCDs can function as the X-ray spectrometer by counting the number of electrons created by the ionization of semiconductor atoms following the photoelectric absorption of a X-ray photon. In order to measure the incident X-ray energy correctly, we have to sum up all the electrons split over several pixels, thus the grade method is conventionally used. We will discuss the possible alternative to this method the fitting method -, which has several advantages over the grade method. By applying this method to the data taken with our CCD chip, we will show that the fitting method can improve the quantum efficiency, is appliable to the analysis of polarized X-ray events, and gives us insights on the structure of CCDs.