45 research outputs found

    A setup for soft proton irradiation of X-ray detectors for future astronomical space missions

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    Protons that are trapped in the Earth's magnetic field are one of the main threats to astronomical X-ray observatories. Soft protons, in the range from tens of keV up to a few MeV, impinging on silicon X-ray detectors can lead to a significant degradation of the detector performance. Especially in low earth orbits an enhancement of the soft proton flux has been found. A setup to irradiate detectors with soft protons has been constructed at the Van-de-Graaff accelerator of the Physikalisches Institut of the University of T\"ubingen. Key advantages are a high flux uniformity over a large area, to enable irradiations of large detectors, and a monitoring system for the applied fluence, the beam uniformity, and the spectrum, that allows testing of detector prototypes in early development phases, when readout electronics are not yet available. Two irradiation campaigns have been performed so far with this setup. The irradiated detectors are silicon drift detectors, designated for the use on-board the LOFT space mission. This paper gives a description of the experimental setup and the associated monitoring system.Comment: 20 pages, 10 figures, 4 table

    The ASTRO-H X-ray Observatory

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    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 via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-2 keV with high spectral resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray

    Создание программного обеспечения для проектирования и расчета ректификационных колонн

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    В работе описаны разработанные и программно реализованные методики и алгоритмы расчета технологических и конструкционных параметров тарельчатых и насадочных ректификационных колонн для разделения двух, многокомпонентных и изотопных смесей. Представлены результаты их верификации. Показана хорошая сходимость результатов расчета с известными литературными данными.This work describes the developed and software implemented methods and algorithms for calculating the technological and design parameters of disc-shaped and packed distillation columns for separating two, multicomponent and isotopic mixtures. The results of the verification of the methods are presented. A good convergence of the calculation results with the known literature data is shown

    The High Resolution Microcalorimeter Soft X-Ray Spectrometer for the Astro-H Mission

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    We are developing the Soft X-Ray Spectrometer for the JAXA Astro-H mission. The instrument features a 5 eV, 36-pixel array of micro calorimeters designed for high spectral resolution from 0.3-12 keV at the focus of an x-ray mirror, providing a field of view of3 x 3 arcmin. The principal components of the spectrometer are the microcalorimeter detector system, a 3-stage ADR and dewar. The dewar is a long-life, hybrid design with a superfluid He cryostat, Joule-Thomson cooler, and Stirling coolers. We describe the present design of the SXS instrument and initial engineering model test results

    Hitomi (ASTRO-H) X-ray Astronomy Satellite

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    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 February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard 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

    The Influence of Political Connection and Institutions to the Performance and Bank Loans of Private Listed Companies

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    我国有着不同于西方发达国家的制度背景和政治制度,政府对市场的管制力度较大,上市公司的高管具有一定的政治背景,其中国有企业本身大股东的政府背景性质,其政治关联很可能是与生俱来的,而民营企业政治关联的形成则具有主动性。改革开放以来,民营经济不断发展壮大,己成为我国经济增长的主要推动力量,因此,研究政治关联对民营公司的影响这一问题在中国更具有现实启发意义。 本文以民营上市公司的高级管理人员是否是前任或现任的政府官员、人大代表或政协委员来衡量公司是否具有政治关联,选取2004年—2008年中国沪深两市所有A股民营上市公司为样本,实证研究了政治关联与制度环境对民营上市公司经营绩效和银行贷款的影响。研究...Chinese current institution and political system are different from the Western developed countries. Under this system, many executives of private listed companies are relevant to politics. Therefore the study of political influence of private companies related to this issue in China is more realistic instructive. This paper focuses on whether the company has the political connection, which measu...学位:管理学硕士院系专业:管理学院财务学系_财务学学号:1762007115174

    Research and Development of a Scintillating Fiber Tracker with SiPM Array Read-Out for Application in Space

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    Scintillating fibers read-out by arrays of silicon photomultipliers can be complementary to silicon strip detectors for particle trackers in space or represent a viable alternative. Less fragile, more flexible, with no need of wire bonds, they can be used in high resolution charged particle tracking detectors for spaceborne experiments. Two prototypes, a 1m1\,\mathrm{m} long and a 70cm70\,\mathrm{cm} long ribbon, made of six layers of 250μm250\,\mu \mathrm{m} diameter fibers, coupled to Hamamatsu silicon photomultiplier arrays and read-out by VATA ASICs have been tested. Preliminary results of a beam test carried out at CERN and the status of the ongoing space qualification process are presented in this contribution
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