Status of the EPIC thin and medium filters on-board XMM-Newton after more than 10 years of operation II: analysis of in-flight data

After more than ten years of operation of the EPIC camera on board the X-ray observatory XMM-Newton we have reviewed the status of its thin and medium filters by performing both analysis of data collected in-flight and laboratory measurements on on-ground back-up filters. We have investigated the status of the EPIC thin and medium filters by performing an analysis of the optical loading in the PN offset maps to gauge variations in the optical and UV transmission of the filters. We both investigated repeated observations of single optically bright targets and performed a statistical analysis of the extent of loading versus visual magnitude at different epochs. We report the results of these measurements

Filters for X-ray detectors on Space missions

Thin filters and gas tight windows are used in Space to protect sensitive X-ray detectors from out-of-band electromagnetic radiation, low-energy particles, and molecular contamination. Though very thin and made of light materials, filters are not fully transparent to X-rays. For this reason, they ultimately define the detector quantum efficiency at low energies. In this chapter, we initially provide a brief overview of filter materials and specific designs adopted on space experiments with main focus on detectors operating at the focal plane of grazing incidence X-ray telescopes. We then provide a series of inputs driving the design and development of filters for high-energy astrophysics space missions. We begin with the identification of the main functional goals and requirements driving the preliminary design, and identify modeling tools and experimental characterization techniques needed to prove the technology and consolidate the design. Finally, we describe the calibration activities required to derive the filter response with high accuracy.We conclude with some hints on materials and technologies presently under investigation for future X-ray missions.Comment: 45 pages, 11 figures Contribution to the Handbook of X-ray and Gamma-ray Astrophysics in the chapter "Detectors for X-ray Astrophysics", edited by Jan-Willem den Herder, Norbert Meidinger, Marco Feroc

NaNet:a low-latency NIC enabling GPU-based, real-time low level trigger systems

We implemented the NaNet FPGA-based PCI2 Gen2 GbE/APElink NIC, featuring GPUDirect RDMA capabilities and UDP protocol management offloading. NaNet is able to receive a UDP input data stream from its GbE interface and redirect it, without any intermediate buffering or CPU intervention, to the memory of a Fermi/Kepler GPU hosted on the same PCIe bus, provided that the two devices share the same upstream root complex. Synthetic benchmarks for latency and bandwidth are presented. We describe how NaNet can be employed in the prototype of the GPU-based RICH low-level trigger processor of the NA62 CERN experiment, to implement the data link between the TEL62 readout boards and the low level trigger processor. Results for the throughput and latency of the integrated system are presented and discussed.Comment: Proceedings for the 20th International Conference on Computing in High Energy and Nuclear Physics (CHEP

Direct sunlight facility for testing and research in HCPV

A facility for testing different components for HCPV application has been developed in the framework of “Fotovoltaico ad Alta Efficienza” (FAE) project funded by the Sicilian Regional Authority (PO FESR Sicilia 2007/2013 4.1.1.1). The testing facility is equipped with an heliostat providing a wide solar beam inside the lab, an optical bench for mounting and aligning the HCPV components, electronic equipments to characterize the I-V curves of multijunction cells operated up to 2000 suns, a system to circulate a fluid in the heat sink at controlled temperature and flow-rate, a data logging system with sensors to measure temperatures in several locations and fluid pressures at the inlet and outlet of the heat sink, and a climatic chamber with large test volume to test assembled HCPV modules

THE ROLE OF BUTYRIC ACID AS A OPROTECTIVE AGENT AGAINST INFLAMMATORY BOWEL DISEASE

Inflammatory Bowel disease (IBD), such as Crohn's disease and ulcerative colitis, are pathologies characterized by a chronic inflammation of the gastrointestinal tract. Their etiopathogenesis is not yet fully understood. Immune system and heat shock proteins (HSPs) dysfunctions are considered to be among the most likely causes of these diseases. Butyrate is a short-chain fatty acid produced by intestinal microflora. It has a trophic, benefical and protective role in the colonic mucosa, and it also induces changes in Hsp levels and localization. It may therefore be a valuable complementary therapeutic agent when used alongside trraditional drugs (mesalazine and corticosteroids) to treat the production of butyrate in the endoluminal environment may promote clinical remission in IBD patients. Due to these characteristics, there has been keen interest in the use of butyrate as a novel therapeutic supplement in the recent years. The current findings need to be validated through further clinical trials to better define the bbiomolecular dynamics of butyrate in the colonocytes of IBD patients

The thin and medium filters of the EPIC camera on-board XMM-Newton: measured performance after more than 15 years of operation

After more than 15 years of operation of the EPIC camera on board the XMM-Newton X-ray observatory, we have reviewed the status of its Thin and Medium filters. We have selected a set of Thin and Medium back-up filters among those still available in the EPIC consortium and have started a program to investigate their status by different laboratory measurements including: UV/VIS transmission, Raman scattering, X-Ray Photoelectron Spectroscopy, and Atomic Force Microscopy. Furthermore, we have investigated the status of the EPIC flight filters by performing an analysis of the optical loading in the PN offset maps to gauge variations in the optical and UV transmission. We both investigated repeated observations of single optically bright targets and performed a statistical analysis of the extent of loading versus visual magnitude at different epochs. We report the results of the measurements conducted up to now. Most notably, we find no evidence for change in the UV/VIS transmission of the back-up filters in ground tests spanning a 2 year period and we find no evidence for change in the optical transmission of the thin filter of the EPIC-pn camera from 2002 to 2012. We point out some lessons learned for the development and calibration programs of filters for X-ray detectors in future Astronomy missions

OBTAINING MESENCHYMAL STEM CELLS FROM ADIPOSE TISSUE OR MURIN ORIGIN: EXPERIMENTAL STUDY.

The aim of this study was to isolate and characterize rat adipose Derived Mesenchymal Stem Cells (AD-MSCs) in order to evaluate their proliferative potential and their ability to different cell types. AD-MSCs and Derived Mesenchymal Stem Cells (BM-MSCs) have the same characteristic in terms of plasticity. The advantage of adipose tissue is that it is an easier accessible source and it offers a large amount of MSCs by less invasive surgical tecniques. MSCs were obtained from subcutaneous adipose tissue of Wistar rats. first of all microbiological controls were made to exclude the presence of bacteria of fungi in then tissue. Adipose tissue was mechanically and enzimatically fragmented and stromal cell fraction was seeded in adherent culture flasks in DMEM 20% FBS. After 48 h the medium was replaced. Cells were characterized by evaluating:1)their ability tho adhere to the plastic; 2) the clonogenic potential by Colony Forming Unit (CFU) assay, 3) their ability to differentiate in 3 mesodermal lineages (adipocytes, osteocytes and chondrocytes). AD-MSCs are able to differentiate in adipocytes, osteocytes and chondrocytes as confirmed by oil red'O staining, von Kossa staining and histological analuysis respectively. This first characterization is essential for the second part of our study in which we are planning to use AD-MSCs in vivo to restore renal function after an induced ischemic damage in experimental animals

Elastic characterization of nanometer-thick polymeric film for astrophysics application with an experimental-numerical method

The x-ray detectors on board astrophysics space missions require optical blocking filters that are highly transparent to x-rays. The filter design typically consists of a polymeric film that is a few tens of nanometers thick coated with aluminium. Due to the large size of the filter membrane (from a few tens to a few hundred square centimeters) and the extreme aspect ratio, together with severe loading conditions during launch and different stoichiometries of the polymer that could change its mechanical properties, a characterization study of the employed material is needed. The plane strain bulge test is a well-accepted methodology for the mechanical testing of structures that are less than a micrometer thick, and especially for freestanding membranes. Unfortunately, testing such ultra-thin films is not a simple task due to residual stress and experimental uncertainty at very low pressure. In this work, the elastic properties of an extremely thin (between 45 and 415 nm) membrane made of bare polyimide and coated with aluminium were derived through adopting a combined experimental-numerical methodology based on the bulge test and numerical simulations

Thermalization of Mesh Reinforced Ultra-Thin Al-Coated Plastic Films: A Parametric Study Applied to the Athena X-IFU Instrument

The X-ray Integral Field Unit (X-IFU) is one of the two focal plane detectors of Athena, a large-class high energy astrophysics space mission approved by ESA in the Cosmic Vision 2015-2025 Science Program. The X-IFU consists of a large array of transition edge sensor micro-calorimeters that operate at similar to 100 mK inside a sophisticated cryostat. To prevent molecular contamination and to minimize photon shot noise on the sensitive X-IFU cryogenic detector array, a set of thermal filters (THFs) operating at different temperatures are needed. Since contamination already occurs below 300 K, the outer and more exposed THF must be kept at a higher temperature. To meet the low energy effective area requirements, the THFs are to be made of a thin polyimide film (45 nm) coated in aluminum (30 nm) and supported by a metallic mesh. Due to the small thickness and the low thermal conductance of the material, the membranes are prone to developing a radial temperature gradient due to radiative coupling with the environment. Considering the fragility of the membrane and the high reflectivity in IR energy domain, temperature measurements are difficult. In this work, a parametric numerical study is performed to retrieve the radial temperature profile of the larger and outer THF of the Athena X-IFU using a Finite Element Model approach. The effects on the radial temperature profile of different design parameters and boundary conditions are considered: (i) the mesh design and material, (ii) the plating material, (iii) the addition of a thick Y-cross applied over the mesh, (iv) an active heating heat flux injected on the center and (v) a Joule heating of the mesh. The outcomes of this study have guided the choice of the baseline strategy for the heating of the Athena X-IFU THFs, fulfilling the stringent thermal specifications of the instrument

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 highly transparent mesh either in stainless steel or niobium. Differential static pressure experiments were carried out on two filter samples. In addition, the roles of the mesh on the mechanical deformation is studied, adopting a finite element model (FEM). The numerical analysis is compared with experimental results and found in good agreement. The FEM is a promising tool that allows to characterize materials and thicknesses in order to optimize the design