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The Soft X-ray Spectrometer (SXS) instrument that flew on the Astro-H observatory was designed to perform imaging and spectroscopy of x-rays in the energy range of 0.2 to 13 keV with a resolution requirement of 7 eV or better. This was accomplished using a 6x6 array of x-ray microcalorimeters cooled to an operating temperature of 50 mK by an adiabatic demagnetization refrigerator (ADR). The ADR consisted of three stages in order to operate using either a 1.2 K superfluid helium bath or a 4.5 K Joule-Thomson (JT) cryocooler as its heat sink. The design was based on the following operating strategy. After launch, while liquid helium was present (cryogen mode), two of the ADR’s stages would be used to single-shot cool the detectors, using the helium as a heat sink. When the helium was eventually depleted (cryogen-free mode), all three ADR stages would be used to continuously cool the helium tank to about 1.5 K, and to single-shot cool the detectors (to 50 mK), using the JT cryocooler as a heat sink. The Astro-H observatory, renamed Hitomi after its successful launch in February 2016, carried approximately 36 liters of helium into orbit. Based on measurements during ground testing, the average heat load on the helium was projected to be 0.66 mW, giving a lifetime of more than 4 years. On day 5, the helium had cooled to

著者人数: 270名（所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 高橋, 忠幸; 国分, 紀秀; 満田, 和久; Baluta, Chris; 坂東, 信尚; 堂谷, 忠靖; 海老沢, 研; 林, 克洋; 廣瀬, 和之; 飯塚, 亮; 石田, 学; 石川, 久美; 石村, 康生; 岩井, 将親; 岩田, 直子; 河野, 太郎; 川崎, 繁男; 小山, 志勇; 前田, 良知; 峯杉, 賢治; 中川, 貴雄; 夏苅, 権; 小川, 博之; 小川, 美奈; 太田, 方之; 岡崎, 健; 尾崎, 正伸; 坂井, 真一郎; 鮫島, 寛明; 佐藤, 悟郎; 佐藤, 理江; 柴野, 靖子; 志田, 真樹; 嶋田, 貴信; Simionescu, Aurora; 菅原, 泰晴; 竹井, 洋; 田村, 隆幸; 田中, 靖郎; 田代, 信; 冨田, 洋; 辻本, 匡弘; 上田, 周太朗; 上野, 史郎; 和田, 篤始; 渡辺, 伸; 山田, 隆弘; 山崎, 典子）, Number of authors: 270 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS): Takahashi, Tadayuki; Kokubun, Motohide; Mitsuda, Kazuhisa; Baluta, Chris; Bando, Nobutaka; Dotani, Tadayasu; Ebisawa, Ken; Hayashi, Katsuhiro; Hirose, Kazuyuki; Iizuka, Ryo; Ishida, Manabu; Ishikawa, Kumi; Ishimura, Kosei; Iwai, Masachika; Iwata, Naoko; Kawano, Taro; Kawasaki, Shigeo; Koyama, Shu; Maeda, Yoshitomo; Minesugi, Kenji; Nakagawa, Takao; Natsukari, Chikara; Ogawa, Hiroyuki; Ogawa, Mina; Ohta, Masayuki; Okazaki, Tsuyoshi; Ozaki, Masanobu; Sakai, Shinichiro; Sameshima, Hiroaki; Sato, Goro; Sato, Rie; Shibano, Yasuko; Shida, Maki; Shimada, Takanobu; Simionescu, Aurora; Sugawara, Yasuharu; Takei, Yoh; Tamura, Takayuki; Tanaka, Yasuo; Tashiro, Makoto; Tomida, Hiroshi; Tsujimoto, Masahiro; Ueda, Shutaro; Ueno, Shiro; Wada, Atsushi; Watanabe, Shin; Yamada, Takahiro; Yamasaki, Noriko Y.), Accepted: 2018-02-05, 資料番号: SA1170333000

We present the overall design and performance of the Astro-H (Hitomi) Soft X-Ray Spectrometer (SXS). The instrument uses a 36-pixel array of x-ray microcalorimeters at the focus of a grazing-incidence x-ray mirror Soft X-Ray Telescope (SXT) for high-resolution spectroscopy of celestial x-ray sources. The instrument was designed to achieve an energy resolution better than 7 eV over the 0.3-12 keV energy range and operate for more than 3 years in orbit. The actual energy resolution of the instrument is 4-5 eV as demonstrated during extensive ground testing prior to launch and in orbit. The measured mass flow rate of the liquid helium cryogen and initial fill level at launch predict a lifetime of more than 4 years assuming steady mechanical cooler performance. Cryogen-free operation was successfully demonstrated prior to launch. The successful operation of the SXS in orbit, including the first observations of the velocity structure of the Perseus cluster of galaxies, demonstrates the viability and power of this technology as a tool for astrophysics.

The Soft X-ray Spectrometer (SXS) onboard the Astro-H (Hitomi) orbiting x-ray observatory featured an array of 36 silicon thermistor x-ray calorimeters optimized to perform high spectral resolution x-ray imaging spectroscopy of astrophysical sources in the 0.3-12 keV band. Extensive pre- flight calibration measurements are the basis for our modeling of the pulse-height-energy relation and energy resolution for each pixel and event grade, telescope collecting area, detector efficiency, and pulse arrival time. Because of the early termination of mission operations, we needed to extract the maximum information from observations performed only days into the mission when the onboard calibration sources had not yet been commissioned and the dewar was still coming into thermal equilibrium, so our technique for reconstructing the per-pixel time-dependent pulse-height-energy relation had to be modified. The gain scale was reconstructed using a combination of an absolute energy scale calibration at a single time using a fiducial from an onboard radioactive source, and calibration of a dominant time-dependent gain drift component using a dedicated calibration pixel, as well as a residual time-dependent variation using spectra from the Perseus cluster of galaxies. The energy resolution was also measured using the onboard radioactive sources. It is consistent with instrument-level measurements accounting for the modest increase in noise due to spacecraft systems interference. We use observations of two pulsars to validate our models of the telescope area and detector efficiency, and to derive a more accurate value for the thickness of the gate valve Be window, which had not been opened by the time mission operations ceased. We use observations of the Crab pulsar to refine the pixel-to-pixel timing and validate the absolute timing.

The Astro-H (Hitomi) Soft X-ray Spectrometer (SXS) was a pioneering imaging x-ray spectrometer with 5 eV energy resolution at 6 keV. The instrument used a microcalorimeter array at the focus of a high-throughput soft x-ray telescope to enable high-resolution non-dispersive spectroscopy in the soft x-ray waveband (0:3-12 keV). We present the suite of ground calibration measurements acquired from 2012-2015, including characterization of the detector system, anti-coincidence detector, optical blocking filters, and filter-wheel filters. The calibration of the 36-pixel silicon thermistor microcalorimeter array includes parameterizations of the energy gain scale and line spread function for each event grade over a range of instrument operating conditions, as well as quantum efficiency measurements. The x-ray transmission of the set of five Al/polyimide thin-film optical blocking filters mounted inside the SXS dewar has been modeled based on measurements at synchrotron beamlines, including with high spectral resolution at the C, N, O, and Al K-edges. In addition, we present the x-ray transmission of the dewar gate valve and of the filters mounted on the SXS filter wheel (external to the dewar), including beryllium, polyimide, and neutral density filters.

The SXS instrument was launched aboard the Astro-H observatory on February 17, 2016. The SXS spectrometer is based on a high sensitivity x-ray calorimeter detector system that has been successfully deployed in many ground and sub-orbital spectrometers. The instrument was to provide essential diagnostics for nearly every class of x-ray emitting objects from the atmosphere of Jupiter to the outskirts of galaxy clusters, without degradation for spatially extended objects. The SXS detector system consisted of a 36-pixel cryogenic microcalorimeter array operated at a heat sink temperature of 50 mK. In pre-flight testing, the detector system demonstrated a resolving power of better than 1300 at 6 keV with a simultaneous band-pass from below 0.3 keV to above 12 keV with a timing precision better than 100 μs. In addition, a solid-state anti-coincidence detector was placed directly behind the detector array for background suppression. The detector error budget included the measured interference from the SXS cooling system and the spacecraft. Additional margin for on-orbit gain-stability, and on-orbit spacecraft interference were also included predicting an on-orbit performance that meets or exceeds the 7 eV FWHM at 6 keV requirement. The actual on-orbit spectral resolution was better than 5 eV FWHM at 6 keV, easily satisfying the instrument requirement. Here we discuss the actual on-orbit performance of the SXS detector system and compare this to performance in pre-flight testing and the on-orbit predictions. We will also discuss the on-orbit gain stability, additional on-orbit interference, and measurements of the on-orbit background.

The Soft X-ray Spectrometer (SXS) is the first space-based instrument to implement redundancy in the operation of a sub-Kelvin refrigerator. The SXS cryogenic system consists of a superfluid helium tank and a combination of Stirling and Joule-Thompson (JT) cryocoolers that support the operation of a 3-stage adiabatic demagnetization refrigerator (ADR). When liquid helium is present, the x-ray microcalorimeter detectors are cooled to their 50 mK operating temperature by two ADR stages, which reject their heat directly to the liquid at ~1.1 K. When the helium is depleted, all three ADR stages are used to accomplish detector cooling while rejecting heat to the JT cooler operating at 4.5 K. Compared to the simpler helium mode operation, the cryogen-free mode achieves the same instrument performance by controlling the active cooling devices within the cooling system differently. These include the three ADR stages and four active heat switches, provided by NASA, and five cryocoolers, provided by JAXA. Development and verification details of this capability are presented within this paper and offer valuable insights into the challenges, successes, and lessons that can benefit other missions, particularly those employing cryogen-free cooling systems.

We summarize results of the initial in-orbit performance of the pulse shape processor (PSP) of the soft x-ray spectrometer instrument onboard ASTRO-H (Hitomi). Event formats, kind of telemetry, and the pulse processing parameters are described, and the parameter settings in orbit are listed. PSP was powered-on two days after launch, and the event threshold was lowered in orbit. PSP worked fine in orbit, and there were no memory error nor SpaceWire communication error until the break-up of spacecraft. Time assignment, electrical crosstalk, and the event screening criteria are studied. It is confirmed that the event processing rate at 100% CPU load is ~200 c/s/array, compliant with the requirement on PSP.

We summarize all the in-orbit operations of the Soft X-ray Spectrometer (SXS) onboard the ASTRO-H (Hit- omi) satellite. The satellite was launched on 2016/02/17 and the communication with the satellite ceased on 2016/03/26. The SXS was still in the commissioning phase, in which the setups were progressively changed. This article is intended to serve as a reference of the events in the orbit to properly interpret the SXS data taken during its short life time, and as a test case for planning the in-orbit operation for future micro-calorimeter missions.

The Soft X-ray Spectrometer instrument on the Astro-H observatory contains a 6x6 array of x-ray microcalorimeters, which is cooled to 50 mK by an adiabatic demagnetization refrigerator (ADR). The ADR consists of three stages in order to provide stable detector cooling using either a 1.2 K superfluid helium bath or a 4.5 K Joule-Thomson (JT) cryocooler as its heat sink. When liquid helium is present, two of the ADR’s stages are used to single-shot cool the detectors while rejecting heat to the helium. After the helium is depleted, all three stages are used to cool both the helium tank (to about 1.5 K) and the detectors (to 50 mK) using the JT cryocooler as its heat sink. The Astro-H observatory, renamed Hitomi after its successful launch in February 2016, carried approximately 36 liters of helium into orbit. On day 5, the helium had cooled sufficiently (

The Hitomi (ASTRO-H) mission is the sixth Japanese X-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E > 2 keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft X-rays to gamma-rays. After a successful launch on 2016 February 17, the spacecraft lost its function on 2016 March 26, but the commissioning phase for about a month provided valuable information on the on-board instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month.

Micro-X is a sounding-rocket experiment that will combine a transition edge sensor (TES) microcalorimeter array with an imaging mirror to obtain high-spectral-resolution images of astronomical X-ray sources. The instrument's resolution across the 0.3-2.5 keV band will be 2 eV. The first flight will target the region of the Bright Eastern Knot of the Puppis A supernova remnant and is slated for January 2011. The obtained high-resolution X-ray spectra will be used to ascertain the temperature and ionization state of the X-ray-emitting gas and to determine its velocity structure. The TES array is read out by a time-division superconducting quantum interference device (SQUID) multiplexing system. The detector front end assembly and the SQUID multiplexing circuit are cooled to the operating temperature of 50 mK with an adiabatic demagnetization refrigerator (ADR). The design of this refrigerator is tailored to the requirements of rocket flight. Stable operation of the TES array close to the ADR magnet will be achieved with a magnetic shielding system, which will be based on a combination of a bucking coil and high-permeability and superconducting shield materials to cancel out residual fields. We describe our progress in developing the Micro-X instrument.

We are developing a gamma-ray spectrometer for the analysis of nuclear materials based on an array of superconducting transition-edge-sensor microcalorimeters. The instrument will include eight columns of time-division-SQUID multiplexing circuitry capable of reading out 256 sensors. Our most recent sensors are bulk (1.5 mm square×0.25 mm thick) superconducting Sn absorbers glued to Mo/Cu bilayer thermometers. When fully populated, the active area of the spectrometer will be 5.76 cm2, and the maximum count rate of the array will approach 20 kHz. Thus, our spectrometer will be comparable to the state-of-the-art 100 keV high-purity-Ge detector in count rate and collecting area, but with an order of magnitude better energy resolution. Half the detectors will be optimized for operation up to 100 keV, and the other half for operation up to 200 keV. A version of the spectrometer with a partially populated detector array was delivered to Los Alamos National Laboratory in June, 2007. We describe the present status of that instrument. In addition, we review results from a prototype array of 14 detectors that achieved 47 eV average energy resolution (full width at half maximum at 103 keV) and 25 eV resolution in the best detector. An important application of this technology is determining the total Pu content in spent reactor fuel without detailed knowledge of the reactor’s operating history.

著者人数: 44名, Accepted: 2006-10-03, 資料番号: SA1000630000

We have measured the electron impact excitation cross sections for the strong iron L-shell 3 {yields} 2 lines of Fe XVIII to Fe XXIV at the EBIT-I electron beam ion trap using a crystal spectrometer and NASA-Goddard Space Flight Centers 6 x 6 pixel array microcalorimeter. The cross sections were determined by direct normalization to the well established cross section of radiative electron capture through a sophisticated model analysis which results in the excitation cross section for the strong Fe L-shell lines at multiple electron energies. This measurement is part of a laboratory X-ray astrophysics program utilizing the Livermore electron beam ion traps EBIT-I and EBIT-II.

X-ray emission following charge exchange has been studied on the University of California Lawrence Livermore National Laboratory electron beam ion traps EBIT-I and EBIT-II using a high-resolution microcalorimeter. The measured spectra include the K-shell emission from hydrogenlike and heliumlike C, N, O, and Ne needed for simulations of cometary x-ray emission. A comparison of the spectra produced in the interaction of O8+ with N2 and CH4 is presented that illustrates the dependence of the observed spectrum on the interaction gas., 11 pages, 2 figures

We are measuring the cross sections for the 3d → 4f and 3d → 5f excitations in Ni- to Ga-like Au in beam plasmas created in the Livermore electron beam ion trap EBIT-I. The measurements are possible by using the high-resolution broadband coverage of the Goddard Space Flight Center micro-calorimeter. The cross sections are determined from the ratio of the intensity of the collisionally excited lines to the intensity of the radiative recombination lines. The value of the excitation cross section of the 3d 3/2 → 5f 5/2 transition in Au 50+ (Cu-like) is presented and compared to distorted wave calculations.

Electron impact excitation cross sections have been measured for iron L-shell 3 {yields} 2 lines of FeXXI to FeXXIV at the EBIT-II electron beam ion trap using a crystal spectrometer and a 6 x 6-element array microcalorimeter. The cross sections were determined by direct normalization to the well established cross section of radiative electron capture and a summary of calculated energy dependent radiative recombination cross sections for electron capture into the ground state fine structure levels of Fe{sup 16+} to Fe{sup 23+} ions is given. The measurement results for 17 lines and their comparison with model calculations are presented. While agreement of the model calculations with experiment is good for most measured lines, significant discrepancies were found for a few lines, including the strongest line in Fe XXI.

A multi-faceted, multi-institutional laboratory astrophysics program is carried out at the Livermore electron beam ion trap facility, which is a mature spectroscopic source with unsurpassed controls and capabilities, and an unparalleled assortment of spectroscopic equipment, including a full complement of grating and crystal spectrometers and a 6x6 micro-calorimeter array. Recent results range from the calibration of x-ray diagnostics, including the Fe XVII and Fe XXV emission lines, extensive lists of L-shell ions, the first laboratory simulation and fit of a cometary x-ray emission spectrum, and the discovery of new spectral diagnostics for measuring magnetic field strengths.

The intensity ratios between 3 → 2 emission lines in Ni XIX were measured on the Livermore electron beam ion trap (EBIT-I) with a flat-field grating spectrometer and the NASA/Goddard Space Flight Center X-ray microcalo-rimeter. The results are consistent with earlier measurements of Fe XVII and other Ne-like ions at Livermore and confirm the problems in the atomic modeling of the direct collisional excitation for Ne-like systems.

We study the effects of high flux on transition-edge sensors by using a non-linear microcalorimeter model with parameters suitable for the Constellation-X mission. A photon event list was created that simulated the flux and spectrum of the Crab nebula incident on the detector when folded through the Constellation-X optics and filters. Simulations show that even at Crab levels of flux, the Con-X microcalorimeter does not “latch” into the normal state.

We present the results of extensive characterization tests of the X-ray Spectrometer (XRS), which will be launched in 2005 as part of the Astro-E2 mission. The XRS will utilize a newly developed 2-D microcalorimeter array of 32 pixels that will provide a resolution of ∼6 eV over the energy range 0.3–10 keV. The detector is characterized by the energy scale and energy resolution, both of which vary with design and operating parameters. We have calibrated the gain scale and energy resolution over a range of operating parameters including bias voltage, temperature, and incident photon flux. We will present the response of the cumulative detector array as well as a measure of the uniformity of the individual pixels. One pixel is physically offset from the array and will be continuously illuminated by a radioactive source in-flight. We will show the accuracy with which this pixel can be used to monitor variations in the focal plane array. Finally, we have illuminated the array with a high-energy continuum source and measured the Hg absorption edges in order to characterize the absorption efficiency of the pixels.

We have developed a model for transition edge sensors to optimize performance under a variety of different conditions. There are three design trade-offs when engineering a microcalorimeter for a particular application: energy resolution, energy range and maximum count rate. All three are interdependent and are determined by various design parameters such as the detector heat capacity, the sharpness of the transition, and the thermal conductance of the detector to the frame. Our model includes all known sources of intrinsic noise in our calorimeters including the observed broad band excess noise. We will present the results of this model, and its predictions for optimally designed microcalorimeters.

Microcalorimeter pulse shape characteristics, such as pulse height, decay constant, and rise time, are dependent on the detector temperature and bias as well as incident photon energy. We examine the nature of the temperature dependency by illuminating the Astro-E2 X-ray Spectrometer microcalorimeter array with X-rays generated by electron impact on a selection of foil targets. The resulting pulses are collected over a range of detector temperatures. We observe and model these pulses by fitting the data with non-linear pulse models. Our aim is to determine a robust method for correcting the energy scale obtained in ground calibration for slight differences in the operating conditions while in orbit.

Characterizing and understanding, in detail, the behavior of a Transition Edge Sensor (TES) is required for achieving an energy resolution of 2 eV at 6 keV desired for future X-ray observatory missions. This paper will report on a suite of measurements (e.g. impedance and I–V among others) and simulations that were developed to extract a comprehensive set of TES parameters such as heat capacity, thermal conductivity, and R(T,I), α(T,I), and βi(T,I) surfaces. These parameters allow for the study of the TES calorimeter behavior at and beyond the small signal regime.

The Livermore electron beam ion trap facility has recently been moved to a new location within LLNL, and new instrumentation was added, including a 32-pixel microcalorimeter. The move was accompanied by a shift of focus toward in situ measurements of highly charged ions, which continue with increased vigor. Overviews of the facility, which includes EBIT-I and SuperEBIT, and the research projects are given, including results from optical spectroscopy, QED, and X-ray line excitation measurements.

The intensity ratios of the 3s → 2p and 3d → 2p lines in Fe XVII were measured on the Livermore electron beam ion trap employing a complementary set of spectrometers, including a high-resolution crystal spectrometer and the Goddard 32 pixel calorimeter. The resulting laboratory data are in agreement with satellite measurements of the Sun and astrophysical sources in collisional equilibrium such as Capella, Procyon, and NGC 4636. The results disagree with earlier laboratory measurements and assertions that processes not accounted for in laboratory measurements must play a role in the formation of the Fe XVII spectra in solar and astrophysical plasmas.

In the course of developing microcalorimeters as detectors for astronomical X-ray spectroscopy, we have undertaken an empirical characterization of non-ideal effects in the doped semiconductor thermometers used with these detectors, which operate at temperatures near 50 mK. We have found three apparently independent categories of such behavior that are apparently intrinsic properties of the variable-range hopping conduction mechanism in these devices: 1/f fluctuations in the resistance, which seems to be a 2D effect; a departure from the ideal coulomb-gap temperature dependence of the resistance at temperatures below T 0 /24; and an electrical nonlinearity that has the time dependence and extra noise that are quantitatively predicted by a simple hot electron model. This work has been done largely with ion-implanted Si:P:B, but similar behaviors have been observed in transmutation doped germanium.

We report measurements of emission cross sections for iron L-shell 3 → 2 lines in Fe23+ performed on the electron beam ion trap EBIT-II using a combination of a crystal spectrometer and the spare 6 × 6 element X-Ray Spectrometer microcalorimeter from the Astro-E X-ray satellite mission. Use of the microcalorimeter enables for first time the normalization of line emission cross sections, i.e., effective electron impact excitation cross sections that include radiative cascades, to the well-established cross section of radiative electron capture, thus allowing the normalization of relative line intensity measurements using crystal spectrometers.

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions developed by the Institute of Space and Astronautical Science (ISAS), with a planned launch in 2015. The ASTRO-H mission is equipped with a suite of sensitive instruments with the highest energy resolution ever achieved at E > 3 keV and a wide energy range spanning four decades in energy from soft X-rays to gamma-rays. The simultaneous broad band pass, coupled with the high spectral resolution of Delta E < 7 eV of the micro-calorimeter, will enable a wide variety of important science themes to be pursued. ASTRO-H is expected to provide breakthrough results in scientific areas as diverse as the large-scale structure of the Universe and its evolution, the behavior of matter in the gravitational strong field regime, the physical conditions in sites of cosmic-ray acceleration, and the distribution of dark matter in galaxy clusters at different redshifts., 24 pages, 18 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray"

We present the development status of the Soft X-ray Spectrometer (SXS) onboard the ASTRO-H mission. The SXS provides the capability of high energy-resolution X-ray spectroscopy of a FWHM energy resolution of < 7eV in the energy range of 0.3 – 10 keV. It utilizes an X-ray micorcalorimeter array operated at 50 mK. The SXS microcalorimeter subsystem is being developed in an EM-FM approach. The EM SXS cryostat was developed and fully tested and, although the design was generally confirmed, several anomalies and problems were found. Among them is the interference of the detector with the micro-vibrations from the mechanical coolers, which is the most difficult one to solve. We have pursued three different countermeasures and two of them seem to be effective. So far we have obtained energy resolutions satisfying the requirement with the FM cryostat.

著者人数：14名, 資料番号: SA1001446000

Superconducting bilayers made of thin films of molybdenum and gold show promise as robust transition-edge sensor (TES) thermometers for calorimeters. We present our first X-ray results from experiments with Mo/Au TES calorimeters on silicon-nitride membranes. These results include analysis of the signal pulse shape and noise as functions of the bias point, which is varied through changing the bias voltage for operation at different places within the superconducting transition and changing the heat sink temperature relative to the transition temperature. Ultimately, we determined that the performance of our devices is limited by the slew rate of the SQUID amplifier used to measure the change in current, which restricts the choice of bias. The amplifier must be replaced before further device characterization and optimization can proceed.

著者人数: 15名, 資料番号: SA1000346000

The 32 pixel laboratory microcalorimeter spectrometer built by the NASA/Goddard Space Flight Center (GSFC) is now an integral part of the spectroscopy suite used routinely by the electron beam ion trap and radiative properties group at the Lawrence Livermore National Laboratory. The second generation laboratory instrument, dubbed the XRS/EBIT, is nearly identical to the XRS instrument on the Suzaku X-ray Observatory, formerly Astro-E2. The detector array is from the same processed wafer and uses the same HgTe absorbers. It is being used to measure the photon emission from a variety of radiation sources. These include X-ray emission from laboratory simulated celestial sources, X-ray emission from highly charged ions of Au, and X-ray emission following charge exchange and radiative electron capture. The wide range of applications demonstrates the versatility of a high-resolution, high-efficiency low-temperature detector that is able to collect data continually with minimal operator servicing.

著者人数: 17名, 資料番号: SA1000334000

著者人数: 16名, 資料番号: SA1000343000

The development of spectroscopic modeling of M-shell tungsten z-pinch plasma is presented. The spectral region from 3.5 to 6.5 A includes three distinct groups of transitions, and the best candidates for M-shell diagnostics are identified. Theoretical modeling is benchmarked with LLNL electron beam ion trap data produced at different energies of the electron beam and recorded by crystal spectrometers and a broadband microcalorimeter. A new high temperature plasma diagnostic tool, x-ray spectropolarimetry, is proposed to study polarization of W line emission and is illustrated using the results of x-pinch polarization-sensitive experiments. The x-ray line polarization of the prominent M-shell tungsten lines is calculated, and polarization markers are identified. The advantage of using x-pinch W wire experiments for the development of M-shell diagnostics is shown.

Microcalorimeter performance is limited by non-ideal effects that were not included in the standard theory of bolometers and microcalorimeters developed 20 years ago by Mather (Appl. Opt. 21 (1982) 1125). These include the hot-electron effect, absorber decoupling, thermometer non-ohmic behavior, and all related extra noise sources. Models that include these effects have been developed and can be used to optimize the design of microcalorimeters for best performance. The design of the array for the XRS detector on the Astro-E2 satellite was completely optimized based on the required performance and on the characteristics of the materials used. The characteristic heat capacity and thermal conductivity of all the detector components have been measured and the values have been used as input to the models to design the detector geometry for best performance. Mechanical modeling has also been carried out in parallel to ensure the mechanical integrity of the microcalorimeter. We report here the analysis involved in the optimization of the detectors, and the comparison between modeled and measured performance.

The square-format 32-pixel microcalorimeter array at the focal plane of the high-resolution X-ray spectrometer on the Astro-E2 X-ray Observatory is the first of a new generation of silicon-based microcalorimeters. This array has numerous advantages over its predecessor, the bilinear array that was launched on Astro-E. Foremost among its benefits are: (1) the energy resolution is improved by a factor of two at 6 keV (now 6 eV FWHM), (2) the thermal time constant is a factor of two faster, and (3) each pixel has a Gaussian line response. We will discuss the design changes that have led to these and other advantages.

We report the latest design and experimental results for a Position-Sensitive Transition-Edge Sensor (PoST). The PoST is motivated by the desire to achieve a larger field-of-view without increasing the number of readout channels. A PoST consists of a one-dimensional array of X-ray absorbers connected on each end to a Transition Edge Sensor (TES). Position differentiation is achieved through a comparison of pulses between the two TESs and X-ray energy is inferred from a sum of the two signals. Optimizing such a device involves studying the available parameter space which includes device properties such as heat capacity and thermal conductivity as well as TES read-out circuitry parameters. We present results for different regimes of operation and the effects on energy resolution, throughput, and position differentiation. Results and implications from a non-linear model developed to study the saturation effects unique to PoSTs are also presented.

We have identified signals resulting from cosmic rays and environmental gamma rays depositing energy in the pixels and in the silicon frame of the Astro-E2/X-Ray Spectrometer microcalorimeter array. Coincidences between pixels and between the array and an anti-coincidence detector determined the nature of the events. Pulse shapes and amplitudes from the cosmic ray events helped refine the thermal model of the array chip. We discuss how future arrays can be optimized either for the greatest background rejection or for the highest source count rates.

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.

Trabajo presentado a la conferencia: "Space Telescopes and Instrumentation: Ultraviolet to Gamma Ray" celebrada en Amsterdam (Holanda) el 1 de julio de 2012.-- et al., 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) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

We present the science and an overview of the Soft X-ray Spectrometer onboard the ASTRO-H mission with emphasis on the detector system. The SXS consists of X-ray focusing mirrors and a microcalorimeter array and is developed by international collaboration lead by JAXA and NASA with European participation. The detector is a 6×6 format microcalorimeter array operated at a cryogenic temperature of 50 mK and covers a 3' ×3' field of view of the X-ray telescope of 5.6 m focal length. We expect an energy resolution better than 7 eV (FWHM, requirement) with a goal of 4 eV. The effective area of the instrument will be 225 cm 2 at 7 keV; by a factor of about two larger than that of the X-ray microcalorimeter on board Suzaku. One of the main scientific objectives of the SXS is to investigate turbulent and/or macroscopic motions of hot gas in clusters of galaxies.

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, focusing hard X-ray mirrors and hard X-ray imaging detectors, and high energy-resolution soft X-ray spectroscopy (0.3-12 keV) provided by thin-foil X-ray optics and a micro-calorimeter array. The mission will also carry an X-ray CCD camera as a focal plane detector for a soft X-ray telescope (0.4-12 keV) and a non-focusing soft gamma-ray detector (40-600 keV) . The micro-calorimeter system is developed by an international collaboration led by ISAS/JAXA and NASA. The simultaneous broad bandpass, coupled with high spectral resolution of Delta E ~7 eV provided by the micro-calorimeter will enable a wide variety of important science themes to be pursued., 18 pages, 12 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2010: Ultraviolet to Gamma Ray"

One of the instruments on the International X-ray Observatory (IXO), under study with NASA, ESA and JAXA, 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 thermometers. The pixels have metallic X-ray absorbers and are read-out by multiplexed SQUID electronics. The requirements for this instrument are demanding. In the central array (40 x 40 pixels) an energy resolution of < 2.5 eV is required, whereas the energy resolution of the outer array is more relaxed (≈ 10 eV) but the detection elements have to be a factor 16 larger in order to keep the number of read-out channels acceptable for a cryogenic instrument. Due to the large collection area of the IXO 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. In this paper we will summarize the instrument status and performance. We will 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.

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.

The ACS Repair (ACS-R) team includes contributors from NASA's Goddard Space Flight Center, Ball Aerospace, and Teledyne Imaging Sensors; It determined that all of the capabilities of the ACS could be restored and created a concept for the ACS-R component of SN4. ACSR will restore the WFC of ACS by replacing the existing CCD Electronics Box (CEB) with the CEB-Replacement (CEB-R) and providing power from a new Low Voltage Power Supply Replacement (LVPS-8). The new LVPS-R will also attempt to restore the HRC function by providing power through the original power bus. In this presentation, we faeus on the concept and technical aspects of the ACS-R.