X-ray calorimeters routinely achieve very high spectral resolution, typically a few eV full width at half maximum (FWHM). Measurements of calorimeter line shapes are usually dominated by the natural linewidth of most laboratory calibration sources. This compounds the data acquisition time necessary to statistically sample the instrumental line broadening, and can add systematic uncertainty if the intrinsic line shape of the source is not well known. To address these issues, we have built a simple, compact monochromatic x-ray source using channel cut crystals. A commercial x-ray tube illuminates a pair of channel cut crystals which are aligned in a dispersive configuration to select the \kaone line of the x-ray tube anode material. The entire device, including x-ray tube, can be easily hand carried by one person and may be positioned manually or using a mechanical translation stage. The output monochromatic beam provides a collimated image of the anode spot with magnification of unity in the dispersion direction (typically 100-200 $μ$m for the x-ray tubes used here), and is unfocused in the cross-dispersion direction, so that the source image in the detector plane appears as a line. We measured output count rates as high as 10 count/s/pixel for the Hitomi Soft X-ray Spectrometer, which had 819 $μ$m square pixels. We implemented different monochromator designs for energies of 5.4 keV (one design) and 8.0 keV (two designs) which have effective theoretical FWHM energy resolution of 0.125, 0.197, and 0.086 eV, respectively; these are well-suited for optimal calibration measurements of state-of-the art x-ray calorimeters. We measured an upper limit for the energy resolution of our \crkaone monochromator of 0.7 eV FWHM at 5.4 keV, consistent with the theoretical prediction of 0.125 eV.
We have measured and characterized the thermal crosstalk in two different arrays of transition-edge sensor (TES) X-ray micro-calorimeters with frequency-domain multiplexing (FDM) readout. The TES arrays are fabricated at SRON and are a 8$\times$8 and a 32$\times$32 "kilo-pixel" uniform array. The amount of crosstalk is evaluated as the ratio between the averaged crosstalk signal and the X-ray pulse amplitudes. The crosstalk ratios (CR) for our detectors are compliant with the requirements for future X-ray space missions, such as Athena X-IFU (CR$< 10^{-3}$ for first-neighbour pixels): we measu…
In the early 2030s, ESAs new X-ray observatory, Athena, is scheduled to be launched. It will carry two main instruments, one of which is the X-ray Integral Field Unit (X-IFU), an X-ray imaging spectrometer, which will consist of an array of several thousand transition-edge sensors (TESs) with a proposed energy resolution of 2.5 eV for photon energies up to 7 keV. At SRON we develop the backup TES array based on Ti/Au bilayers with a transition temperature just below 100 mK. In this contribution we will give a broad overview of the properties and capabilities of these state-of-the-art detectors…
We present an overview of the ASTRO-H (Hitomi) Soft X-Ray Spectrometer (SXS) and the X-Ray Imaging and Spectrometer Mission (XRISM) {\it Resolve} spectrometer. In each, a 36-pixel X-ray micro-calorimeter array operated at 50 mK covers a $3 \times 3$ arc-minute field of view. The instruments are designed to achieve an energy resolution of better than 7 eV over the 0.3 -- 12 keV energy range and operate for more than 3 years in orbit. Actually, the SXS achieved the energy resolution of $\sim$5 eV in orbit, but it was lost after only a month of operation due to the loss of spacecraft attitude con…
We present a characterization of the sensitivity of TES X-ray micro-calorimeters to environmental conditions under frequency-domain multiplexing (FDM) readout. In the FDM scheme, each TES in a readout chain is in series with a LC band-pass filter and AC biased with an independent carrier at MHz range. Using TES arrays, cold readout circuitry and warm electronics fabricated at SRON and SQUIDs produced at VTT Finland, we characterize the sensitivity of the detectors to bias voltage, bath temperature and magnetic field. We compare our results with the requirements for the Athena X-IFU instrument,…
Gamma rays, electrons and positrons up to 3 TeV with the Fermi Gamma-ray Space Telescope
费米伽马射线太空望远镜（英语：Fermi Gamma-ray Space Telescope），原名伽马射线大面积太空望远镜（Gamma-ray Large Area Space Telescope，GLAST），于2008年6月11日发射升空。它的主要仪器是大面积望远镜（LAT），可探测20 MeV至300 GeV以上的伽马射线。它是一台成对转换望远镜，有16个相同的塔（跟踪器和热量计），覆盖着反符合探测器以拒绝带电粒子。量热计是CsI（Tl）晶体的速观阵列，排列在8个交替的正交层中，具有8.6辐射长度的总厚度。在本文中，我们将介绍LAT的性能，特别注意量热计，它提供了一个很好的能量测量高达3 TeV。我们还将审查其运行4年后的一些科学成果，重点是延伸到极高能量的测量，如河外漫发射光谱、宇宙电子光谱和正电子分数。
We are developing the frequency domain multiplexing (FDM) read-out of transition-edge sensor (TES) microcalorimeters for the X-ray Integral Field Unit (X-IFU) instrument on board of the future European X-Ray observatory Athena. The X-IFU instrument consists of an array of $\sim$3840 TESs with a high quantum efficiency ($>$90 \%) and spectral resolution $ΔE$=2.5 eV $@$ 7 keV ($E/ΔE\sim$2800). FDM is currently the baseline readout system for the X-IFU instrument. Using high quality factor LC filters and room temperature electronics developed at SRON and low-noise two stage SQUID amplifiers provi…
Athena is the large mission selected by ESA in 2013 to investigate the science theme "Hot and Energetic Universe" and presently scheduled for launch in 2028. One of the two instruments located at the focus of the 12 m-long Athena telescope is the X-ray Integral Field Unit (X-IFU). This is an array of TES micro-calorimeters that will be operated at temperatures of 50 mK in order to perform high resolution spectroscopy with an energy resolution down to 2.5 eV at energies < 7 keV. In order to cope with the large dynamical range of X-ray fluxes spanned by the celestial objects Athena will be obser…
Optimization of the Orbiting Wide-angle Light Collectors (OWL) Mission for Charged-Particle and Neutrino Astronomy
OWL利用地球大气层作为巨大的量热计，充分实现新兴的带电粒子天文学领域，对超高能宇宙射线（UHECR）进行高统计测量，并寻找UHE中微子和光子的来源。在~4 x 10^19 eV以上的格赖森-扎采平-库兹明（GZK）抑制的确认表明，大多数UHECR起源于天体物理学对象。更高能量的粒子必须来自大约100 Mpc的来源，并被预测的星系际/星系磁场偏转约1度。皮埃尔俄歇阵列，望远镜阵列和未来的JEM-EUSO国际空间站任务将开启带电粒子天文学，但需要更大的曝光才能完全识别和测量单个源的光谱。OWL在近赤道轨道上使用两台光学孔径为3米、视场为45度的大型望远镜。对一个为期五年的猫头鹰任务的模拟表明，在全孔径约6 x 10^19 eV时，暴露量约为10^6 km^2 sr/年。在不同高度和航天器间隔的观测优化了对UHECR和中微子的灵敏度。OWL的立体事件重建几乎不受轨道倾斜的影响，并且对大气条件非常宽容。可选的单目模式提供了更高的可靠性，并可以增加瞬时孔径。OWL能完全再现水平和向上运动的簇射，因此对UHE中微子具有很高的灵敏度。可充气结构光学和硅光电倍增器的新能力可以大大提高光子灵敏度，降低中微子探测的能量阈值，或者使用更高的轨道增加可视面积。原始和优化的OWL任务和增强的科学能力之间的设计交易进行了描述。
