Thermal modelling of the ATHENA X-IFU filters
Copyright 2018 Society of Photo-Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. The X-IFU instrument of the ATHENA mission requires a set of thermal filters to reduce the photon shot noise onto its cryogenic detector and to protect it from molecular contamination. A set of five filters, operating at different nominal temperatures corresponding to the cryostat shield temperatures, is currently baselined. The knowledge of the actual filter temperature profi…
Synchrotron x-ray transmission measurements and modeling of filters investigated for Athena
International audience; Advanced Telescope for High-Energy Astrophysics is a large-class astrophysics space mission selected by the European Space Agency to study the theme "Hot and Energetic Universe." The mission essentially consists of a large effective area x-ray telescope and two detectors: the X-ray Integral Field Unit (X-IFU) and the Wide Field Imager (WFI). Both instruments require filters to shield from out-of-band radiation while providing high transparency to x-rays. The mission is presently in phase B; thus, to consolidate the preliminary design, investigated filter materials need to be properly characterized by experimental test campaigns. We report results from high-resolution…
Filters design and characterization for LAD instrument onboard eXTP
Copyright 2022 Society of Photo‑Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this publication for a fee or for commercial purposes, and modification of the contents of the publication are prohibited. The LAD (Large Area Detector) instrument, onboard the Sino-European mission eXTP (enhanced X-ray Timing and Polarimetry), will perform single-photon, high-resolution timing and energy measurements, in the energy range 2–30 keV, with a large collecting area. Its silicon drift detectors need shielding from NIR/Vis/UV light by astrophysical sources and the bright Ea…
Deformation analysis of ATHENA test filters made of plastic thin films supported by a mesh under differential static pressure
Within ESA Cosmic Vision 2015-2025 Science Program, ATHENA was selected to be a Large-class high energy astrophysics space mission. The observatory will be equipped with two interchangeable focal plane detectors named X-Ray Integral Field Unit (X-IFU) and Wide Field Imager (WFI). In order to optimally exploit the detector sensitivity, X-ray transparent filters are required. Such filters need to be extremely thin to maximize the X-ray transparency, that is, no more than a few tens of nm, still they must be able to sustain the severe stresses experienced during launch. Partially representative test filters were made with a thin polypropylene film, coated with Ti, and supported by a thin highl…
Carbon nanotubes thin filters for x-ray detectors in space
In this paper, we present the first results from an investigation performed on nanometric thin pellicles based on carbon nanotubes (CNT) of potential interest for manufacturing large area optical blocking filters to protect soft X-ray detectors in astrophysics space missions. In order to evaluate the effective capability of such materials to block UV/VIS/IR radiation, while being highly transparent in the soft X-rays and strong enough to withstand the severe launch stresses, we have performed a suite of characterization measurements. These include: UV/VIS/IR and X-ray absorption spectroscopy, X-ray Photoelectron Spectroscopy and Scanning Electron Microscopy on bare and Al coated small self-…
Covariance and correlation estimators in bipartite complex systems with a double heterogeneity
Complex bipartite systems are studied in Biology, Physics, Economics, and Social Sciences, and they can suitably be described as bipartite networks. The heterogeneity of elements in those systems makes it very difficult to perform a statistical analysis of similarity starting from empirical data. Though binary Pearson's correlation coefficient has proved effective to investigate the similarity structure of some real-world bipartite networks, here we show that both the usual sample covariance and correlation coefficient are affected by a bias, which is due to the aforementioned heterogeneity. Such a bias affects real bipartite systems, and, for example, we report its effects on empirical dat…
Structure and evolution of a European Parliament via a network and correlation analysis
We present a study of the network of relationships among elected members of the Finnish parliament, based on a quantitative analysis of initiative co-signatures, and its evolution over 16 years. To understand the structure of the parliament, we constructed a statistically validated network of members, based on the similarity between the patterns of initiatives they signed. We looked for communities within the network and characterized them in terms of members' attributes, such as electoral district and party. To gain insight on the nested structure of communities, we constructed a hierarchical tree of members from the correlation matrix. Afterwards, we studied parliament dynamics yearly, wi…
Radio frequency shielding of thin aluminized plastic filters investigated for the ATHENA X-IFU detector
Copyright 2018 Society of Photo-Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. The X-ray Integral Field Unit (X-IFU) is one of the two detectors of the ATHENA astrophysics space mission approved by ESA in the Cosmic Vision 2015-2025 Science Programme. The X-IFU consists of a large array of transition edge sensors (TES) micro-calorimeters covering a field of view of 5' diameter, sensitive in the energy range 0.2-12 keV, and providing a spectral resolution…
Electroplated bismuth absorbers for planar NTD-Ge sensor arrays applied to hard x-ray detection in astrophysics
Single sensors or small arrays of manually assembled neutron transmutation doped germanium (NTD-Ge) based microcalorimeters have been widely used as high energy-resolution detectors from infrared to hard X-rays. Several planar technological processes were developed in the last years aimed at the fabrication of NTD-Ge arrays, specifically designed to produce soft X-ray detectors. One of these processes consists in the fabrication of the absorbers. In order to absorb efficiently hard X-ray photons, the absorber has to be properly designed and a suitable material has to be employed. Bismuth offers interesting properties in terms of absorbing capability, of low heat capacity (needed to obtain h…
The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase
The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer, studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory, a versatile observatory designed to address the Hot and Energetic Universe science theme, selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), it aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over an hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (i…
Structure and Evolution of a European Parliament via a Network and Correlation Analysis
We present a study of the network of relationships among elected members of the Finnish parliament, based on a quantitative analysis of initiative co-signatures, and its evolution over 16 years. To understand the structure of the parliament, we constructed a statistically validated network of members, based on the similarity between the patterns of initiatives they signed. We looked for communities within the network and characterized them in terms of members’ attributes, such as electoral district and party. To gain insight on the nested structure of communities, we constructed a hierarchical tree of members from the correlation matrix. Afterwards, we studied parliament dynamics yearly, wi…