Salvatore Varisco
Pubblicazioni/Publications
pubblicazioni come coautore/co-authored papers
Refereed
2016
- The thin and medium filters of the EPIC camera on-board XMM-Newton: measured performance after more than 15 years of operation
Abstract
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.
Experimental Astronomy, Volume 42, Issue 2, pp.179-197Oct 2016
2011
- Tests of lobster eye optics for small space X-ray telescope
Abstract
The Lobster eye design for a grazing incidence X-ray optics provides wide field of view of the order of many degrees, for this reason it can be a convenient approach for the construction of space all-sky X-ray monitors. We present preliminary results of tests of prototype lobster eye X-ray optics in quasi parallel beam full imaging mode conducted using the 35 m long X-ray beam-line of INAF-OAPA in Palermo (Italy). X-ray images at the focal plane have been taken with a microchannel plate (MCP) detector at several energy values from 0.3 to 8 keV. The gain, the field of view and the angular resolution have been measured and compared with theoretical values.
Nuclear Instruments and Methods in Physics Research Section A, Volume 633, p. S169-S171.May 2011
2008
- Experimental evidence of an incomplete thermalization of the energy in an x-ray microcalorimeter with a Ta /Au absorber
Abstract
We have conducted an experimental test at our XACT facility using an x-ray microcalorimeter with Ta /Au absorber and neutron transmutation doped germanium thermal sensor. The test was aimed at measuring the percentage of energy effectively thermalized after absorption of x-ray photons in superconducting tantalum. Moreover, in general, possible formation of long living quasiparticles implies that by using a superconducting absorber, a fraction of the deposited energy could not be thermalized on the useful time scale of the thermal sensor. To investigate this scenario, we exploited an absorber made of gold, where no energy trapping is expected, with a small piece of superconducting tantalum attached on top. We obtained evidence that the thermalization of photons absorbed in tantalum is delayed by energy trapping from quasiparticles. We compare the experimental results with numerical simulations and derive a value for the intrinsic lifetime of quasiparticles.
Review of Scientific Instruments, Volume 79, Issue 5, pp. 053905-053905-4 (2008).May 2008
2007
- The X-Ray Telescope (XRT) for the Hinode Mission
Abstract
The X-ray Telescope (XRT) of the Hinode mission provides an unprecedented combination of spatial and temporal resolution in solar coronal studies. The high sensitivity and broad dynamic range of XRT, coupled with the spacecraft’s onboard memory capacity and the planned downlink capability will permit a broad range of coronal studies over an extended period of time, for targets ranging from quiet Sun to X-flares. This paper discusses in detail the design, calibration, and measured performance of the XRT instrument up to the focal plane. The CCD camera and data handling are discussed separately in a companion paper.
Solar Physics, Volume 243, Issue 1, pp.63-86Jun 2007
1997
- Effects of Interference and Oxidation on the UV/Visible Rejection Properties of Filters for Soft X-ray Detectors
Abstract
Not Available
Experimental Astronomy, v. 7, Issue 1, p. 51-63.n/a 1997
Not Refereed
2018
- Chemical Evolution of Interstellar Methanol Ice Analogs upon Ultraviolet Irradiation: The Role of the SubstrateThe Astrophysical Journal, Volume 858, Issue 1, article id. 35, 10 pp. (2018).May 2018
2015
- Manufacturing and testing a thin glass mirror shell with piezoelectric active control
Abstract
Optics for future X-ray telescopes will be characterized by very large aperture and focal length, and will be made of lightweight materials like glass or silicon in order to keep the total mass within acceptable limits. Optical modules based on thin slumped glass foils are being developed at various institutes, aiming at improving the angular resolution to a few arcsec HEW. Thin mirrors are prone to deform, so they require a careful integration to avoid deformations and even correct forming errors. On the other hand, this offers the opportunity to actively correct the residual deformation: a viable possibility to improve the mirror figure is the application of piezoelectric actuators onto the non-optical side of the mirrors, and several groups are already at work on this approach. The concept we are developing consists of actively integrating thin glass foils with piezoelectric patches, fed by voltages driven by the feedback provided by X-rays. The actuators are commercial components, while the tension signals are carried by a printed circuit obtained by photolithography, and the driving electronic is a multi-channel low power consumption voltage supply developed inhouse. Finally, the shape detection and the consequent voltage signal to be provided to the piezoelectric array are determined in X-rays, in intra-focal setup at the XACT facility at INAF/OAPA. In this work, we describe the manufacturing steps to obtain a first active mirror prototype and the very first test performed in X-rays.
Proceedings of the SPIE, Volume 9603, id. 96031N 9 pp. (2015).Sep 2015
2014
- Direct sunlight facility for testing and research in HCPV
Abstract
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.
AIP Conference Proceedings, Volume 1616, Issue 1, p.158-161Sep 2014
2013
- Status of the EPIC thin and medium filters on-board XMM-Newton after more than 10 years of operation I: laboratory measurements on back-up filters
Abstract
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 laboratory measurements on back-up filters, and analysis of data collected in-flight. 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, X-ray transmission, RAMAN IR spectroscopy, X-Ray Photoelectron Spectroscopy, and Atomic Force Microscopy. We report the results of the measurements conducted up to now, and point out some lessons learned for the development and calibration programs of filters for X-ray detectors in future Astronomy missions.
Proceedings of the SPIE, Volume 8859, id. 885914 12 pp. (2013).Sep 2013 - 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
Abstract
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.
Proceedings of the SPIE, Volume 8859, id. 885915 6 pp. (2013).Sep 2013 - Investigation on the status of the XMM-Newton EPIC T and M filters after more than 10 years of operation .
Abstract
After more than ten years of operation of the EPIC camera on board XMM-Newton, we have started an investigation to review the status of the thin and medium filters by performing laboratory measurements on back-up filters, and on-board calibration measurements. The laboratory measurements will consist of: UV/VIS/IR transmission measurements, X-ray transmission measurements, and microscopic investigations. The on board calibration measurements will include: X-ray transmission measurements, measurement of optical loading, and measurement of the spatial homogeneity. We present the plan of the activities and preliminary results.
Memorie della Societa Astronomica Italiana, v.84, p.829 (2013)n/a 2013
2011
- Lobster eye optics for nano-satellite x-ray monitor
Abstract
The Lobster eye design for a grazing incidence X-ray optics provides wide field of view of the order of many degrees, for this reason it would be a convenient approach for the construction of space X-ray monitors. In this paper, we compare previously reported measurements of prototype lobster eye X-ray optics called P-25 with computer simulations and discuss differences between the theoretical end experimentally obtained results. Usability of this prototype lobster eye and manufacturing technology for the nano-satellite mission is assessed. The specific scientific goals are proposed.
Proceedings of the SPIE, Volume 8076, id. 80760C (2011).May 2011
2009
- Planar Technology for NDT-Ge X-Ray Microcalorimeters: Absorber Fabrication
Abstract
We have investigated the electroplating process to deposit thick uniform films of tin on a Ge wafer coated with Spin-On Glass, in order to fabricate the absorbers for Ge microcalorimeter arrays. Here we discuss some technological details and propose two alternative metal bilayer to be used as seed for the electroplating.
The Thirteenth International Workshop on Low Temperature Detectors-LTD13. AIP Conference Proceedings, Volume 1185. AIP Conference Proceedings, Volume 1185, Issue 1, p.112-114Dec 2009 - Simbol-X Mirror Module Thermal Shields: I-Design and X-Ray Transmission
Abstract
The Simbol-X mission is designed to fly in formation flight configuration. As a consequence, the telescope has both ends open to space, and thermal shielding at telescope entrance and exit is required to maintain temperature uniformity throughout the mirrors. Both mesh and meshless solutions are presently under study for the shields. We discuss the design and the X-ray transmission.
SIMBOL-X: FOCUSING ON THE HARD X-RAY UNIVERSE: Proceedings of the 2nd International Simbol-X Symposium. AIP Conference Proceedings, Volume 1126, pp. 44-47 (2009).May 2009
2008
- Calibration of the SphinX experiment at the XACT facility in Palermo
Abstract
Three of the four detectors of the SphinX experiment to be flown on the Russian mission Coronas-Photon have been measured at the XACT Facility of the Palermo Observatory at several wavelengths in the soft X-ray band. We describe the instrumental set-up and report some measurements. The analysis work to obtain the final calibration is still in progress.
Space Telescopes and Instrumentation 2008: Ultraviolet to Gamma Ray. Edited by Turner, Martin J. L.; Flanagan, Kathryn A. Proceedings of the SPIE, Volume 7011, article id. 70112U, 6 pp. (2008).Jul 2008 - Test of x-ray microcalorimeters with bilayer absorbers
Abstract
Superconducting absorbers for thermal X-ray microcalorimeters should convert into thermalized phonons and transfer to the thermal sensor most of the energy deposited by single photons, on a time scale as short as a few tens of microseconds. Since deposition of X-ray energy in a superconductor produces quasiparticles by breaking up of Cooper pairs, the thermalization efficiency depends on the time scale on which they survive within the absorber volume, trapping part of the absorbed energy. According to the predicted values of their microscopic parameters, in many standard type-I superconducting metals the quasiparticle life time at very low temperatures results too long to allow for recombination on the relatively short time scale of the thermal sensors. In type-II superconductors the existence of a mixed state with Abrikosov vortices could speed up the recombination process and increase the efficiency of thermalization. We discuss this topic by presenting experimental results of laboratory tests conducted on tantalum and lead-bismuth absorbers in a comparison with an absorber made of gold, where no trapping is expected.
High Energy, Optical, and Infrared Detectors for Astronomy III. Edited by Dorn, David A.; Holland, Andrew D. Proceedings of the SPIE, Volume 7021, article id. 70211M, 7 pp. (2008).Jul 2008 - Detailed Calibration of SphinX instrument at the Palermo XACT facility of INAF-OAPA
Abstract
The Solar photometer in X-rays (SphinX) experiment is scheduled for launch late summer 2008 on-board the Russian CORONAS-Photon satellite. SphinX will use three silicon PIN diode detectors with selected effective areas in order to record solar spectra in the X-ray energy range 0.3-15 keV with unprecedented temporal and medium energy resolution. High sensitivity and large dynamic range of the SphinX instrument will give for the first time possibility of observing solar soft X-ray variability from the weakest levels, ten times below present thresholds, to the largest X20+ flares. We present the results of the ground X-ray calibrations of the SphinX instrument performed at the X-ray Astronomy Calibration and Testing (XACT) facility of INAF-OAPA. The calibrations were essential for determination of SphinX detector energy resolution and efficiency. We describe the ground tests instrumental set-up, adopted measurement techniques and present results of the calibration data analysis.
37th COSPAR Scientific Assembly. Held 13-20 July 2008, in Montréal, Canada., p.3114n/a 2008
2007
- Calibration of the lunar orbital x-ray fluorescence imaging spectrometer (LOXIA) of Chang
Abstract
The Lunar Orbital X-ray Fluorescence Imaging Spectrometer (LOXIA) designed and constructed at the Institute of High Energy Physics of the Chinese Academy of Sciences to perform chemical composition analysis of the Moon surface will operate on-board the Chang'E-1 mission, the first Chinese lunar spacecraft to be launched in 2007. We report the main results of the calibration measurements that we have performed using the X-ray beamline of the XACT facility of INAFOsservatorio Astronomico di Palermo G.S. Vaiana to determine the quantum efficiency of the XRS detector in the soft X-rays as a function of photon energy and angle of incidence.
UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XV. Edited by Siegmund, Oswald H. Proceedings of the SPIE, Volume 6686, article id. 668615, 13 pp. (2007).Sep 2007
2006
- The Palermo XACT facility: a new 35 m long soft x-ray beam-line for the development and calibration of next-generation x-ray observatories
Abstract
The X-ray Astronomy Calibration and Testing (XACT) facility of the Instituto Nazionale di Astrofisica (INAF) at Osservatorio Astronomico di Palermo has recently undergone a major upgrade with the design and construction of a 35 meter long vacuum beam-line operating in the soft X-rays (0.1-20 keV) and the addition of new hardware to meet the requirements for testing and calibration of next generation X-ray missions. We report on the present configuration of the facility and briefly survey the range of its applications.
Space Telescopes and Instrumentation II: Ultraviolet to Gamma Ray. Edited by Turner, Martin J. L.; Hasinger, Günther. Proceedings of the SPIE, Volume 6266, id. 62663F (2006).Jun 2006 - Study and implementation of a soft X-ray 100 eV -20 keV fixed exit monochromator system
Abstract
We describe a "built in house" X-ray monochromator which produces a fixed exit X-ray beam tunable in the full energy range 0.1 - 20 keV. The system is based on a double diffraction on two large size parallel crystals positioned using a remotely controlled micropositioning system in order to keep the position of the monochromatic beam for any chosen energy. Up to six different diffracting elements can be selected without breaking the vacuum. This allows to cover the full energy range of interest. The system is part of an upgrading project of the XACT facility at the Istituto Nazionale di Astrofisica - Osservatorio Astronomico di Palermo G.S. Vaiana, and will be employed for the testing and calibration of filters, detectors and optics at X-ray wavelengths.
Space Telescopes and Instrumentation II: Ultraviolet to Gamma Ray. Edited by Turner, Martin J. L.; Hasinger, Günther. Proceedings of the SPIE, Volume 6266, id. 62663G (2006).Jun 2006
2005
- Calibration of the Solar-B x-ray optics
Abstract
The Solar-B X-ray telescope (XRT) is a grazing-incidence modified Wolter I X-ray telescope, of 35 cm inner diameter and 2.7 m focal length. XRT, designed for full sun imaging over the wavelength 6-60 Angstroms, will be the highest resolution solar X-Ray telescope ever flown. Images will be recorded by a 2048 X 2048 back-illuminated CCD with 13.5 μm pixels (1 arc-sec/pixel ) with full sun field of view. XRT will have a wide temperature sensitivity in order to observe and discriminate both the high (5-10 MK) and low temperature (1-5 MK) phenomena in the coronal plasma. This paper presents preliminary results of the XRT mirror calibration performed at the X-ray Calibration Facility, NASA-MSFC, Huntsville, Alabama during January and February 2005. We discuss the methods and the most significant results of the XRT mirror performance, namely: characteristics of the point response function (PSF), the encircled energy and the effective area. The mirror FWHM is 0.8" when corrected for 1-g, finite source distance, and CCD pixelization. With the above corrections the encircled energy at 27 μm and 1keV is 52%. The effective area is greater than 2cm2 at 0.5keV and greater than 1.7cm2 at 1.0keV.
Optics for EUV, X-Ray, and Gamma-Ray Astronomy II. Edited by Citterio, Oberto; OAug 2005 - The Calibration of the Solar-B X-ray Telescope (XRT)
Abstract
The Solar-B X-ray telescope (XRT) is designed to have a wide temperature sensitivity in order to observe and analyze both the high (5-10 MK) and low temperature (1-5 MK) phenomena in the coronal plasma. It will be the telescope with the highest resolution ever flown for solar coronal studies. The telescope is designed for full Sun imaging over the wavelength range 6-60 Angstroms. The XRT is a grazing-incidence modified Wolter I X-ray telescope, of 35 cm inner diameter and 2.7 m focal length. The 2048 X 2048 back illuminated CCD has 13.5 µm pixels, corresponding to 1 arcsecond. The filter set used in the XRT, mounted at the telescope entrance and near the focal plane, will perform three functions: (1) to reduce the heat load inside the telescope, (2) to reduce the incoming visible light and (3) to provide spectral diagnostics to determine coronal plasma temperatures. This paper will present the results of the XRT calibration performed at the X-ray Calibration Facility, NASA-MSFC, Huntsville, Alabama in January 2005. We will discuss the methods and the most significant results of the XRT performance, namely: imaging properties, encircled energy, the point response function and the effective area in the 0.2-2 keV energy range.
American Geophysical Union, Spring Meeting 2005, abstract #SP43A-01May 2005
2004
- Thin-shell plastic lenses for space and laboratory applications
Abstract
We have identified an inexpensive, readily available, mechanically stable, extremely smooth, elastic, and mechanically uniform plastic suitable for thin film X-ray optics. Polyethylene terephthalate (PET) is easily deformed without losing its elastic properties or surface smoothness. Most important, PET can be coated with mono- or multilayers that reflect X-rays at grazing incidence. We have used these properties to produce X-ray optics made either as a concentric nest of cylinders or as a spiral. We have produced accurately formed shells in precisely machined vacuum mandresl or used a pin and wheel structure to form a continuously wound spiral. The wide range of medical, industrial and scientific applications for our technology includes: a monochromatic X-ray collimater for medical diagnostics, a relay optic to transport an X-ray beam from the target in a scanning electron microscop0e to a lithium-drifted silicon and microcalorimeter detectors and a satellite mounted telescope to collect celestial X-rays. A wide variety of mono- and multilayer coatings allow X-rays up to ~100 keV to be reflected. Our paper presents data from a variety of diagnostic measurements on the properties of the PET foil and imaging results form single- and multi-shell lenses.
X-Ray Sources and Optics. Edited by MacDonald, Carolyn A.; Macrander, Albert T.; Ishikawa, Tetsuya; Morawe, Christian; Wood, James L. Proceedings of the SPIE, Volume 5537, pp. 82-93 (2004).Nov 2004 - Calibration of the XRT-SOLARB flight filters at the XACT facility of INAF-OAPA
Abstract
The X-Ray Telescope (XRT) experiment on-board the Japanese satellite SOLAR-B (launch in 2006) aimed at providing full Sun field of view at ~ 1.5" angular resolution, will be equipped with two wheels of focal-plane filters to select spectral features of X-ray emission from the Solar corona, and a front-end filter to significantly reduce the visible light contamination. We present the results of the X-ray calibrations of the XRT flight filters performed at the X-ray Astronomy Calibration and Testing (XACT) facility of INAF-OAPA. We describe the instrumental set-up, the adopted measurement technique, and present the transmission vs. energy and position measurements.
UV and Gamma-Ray Space Telescope Systems. Edited by Hasinger, Günther; Turner, Martin J. L. Proceedings of the SPIE, Volume 5488, pp. 423-439 (2004).Oct 2004 - Calibration of the XRT-SOLARB flat mirror samples at the XACT Facility of INAF-OAPA
Abstract
The X-Ray Telescope (XRT) experiment on-board the Japanese satellite SOLAR-B (launch in 2006) is equipped with a modified Wolter I grazing incidence X-ray telescope (focal length 2700 mm) to image the full Sun at ~ 1.5" angular resolution onto a 2048 x 2048 back illuminated CCD focal plane detector. The X-ray telescope consisting of one single reflecting shell is coated with ion beam sputtered Iridium over a binding layer of Chromium to provide nearly 5 square centimetres effective area at 60 Å. We present preliminary results of X-ray calibrations of the XRT flat mirror samples performed at the X-ray Astronomy Calibration and Testing (XACT) facility of INAF-OAPA. We describe the instrumental set-up, the adopted measurement technique, and present the measured reflectivity vs. angle of incidence at few energies.
UV and Gamma-Ray Space Telescope Systems. Edited by Hasinger, Günther; Turner, Martin J. L. Proceedings of the SPIE, Volume 5488, pp. 440-448 (2004).Oct 2004 - Astronomical soft x-ray mirrors reflectivity enhancement by multilayer coatings with carbon overcoating
Abstract
A number of X-ray astronomical missions of near future will make use of hard X-ray optics with broad-band multilayer coatings. However multilayer mirrors can be also useful to enhance the effective area of a given X-ray telescope in the "classical" low energy X-ray band (0.1 - 10 keV), the window where X-ray spectroscopy provides very useful plasma diagnostics) with a consistent gain with respect to usual single-layer reflectors. Multilayers for soft X-rays are based on stacks with constant d-spacing (in order to minimize the loss due to the photoelectric effect). A further gain in reflectivity (however only restricted to the energy range between 0.5 and 4 keV) can be achieved by using a low density material as a first external layer of the film, with the role of reducing the photoelectric absorption effect when the mirror acts in total external reflection regime (Carbon is the most performing material for this specific scope). In this paper the impact of using soft X-ray multilayer mirrors in future X-ray telescopes is discussed, and soft X-ray reflectivity tests performed on prototype samples presented.
UV and Gamma-Ray Space Telescope Systems. Edited by Hasinger, Günther; Turner, Martin J. L. Proceedings of the SPIE, Volume 5488, pp. 481-491 (2004).Oct 2004 - A single stage adiabatic demagnetization refrigerator for testing X-ray microcalorimeters
Abstract
A single stage Adiabatic Demagnetization Refrigerator (ADR), has been set-up at the X-ray Astronomy Calibration and Testing (XACT) facility of INAF - Osservatorio Astronomico di Palermo G.S. Vaiana, for the development and testing of cryogenic X-ray detectors for laboratory and astrophysical applications. The ADR allows to cool detectors at temperatures below 40 mK and to maintain them at constant operating temperature for many hours. We describe the design and construction of the ADR and present test results and performances.
High-Energy Detectors in Astronomy. Edited by Holland, Andrew D. Proceedings of the SPIE, Volume 5501, pp. 366-384 (2004).Sep 2004
2003
- Monitoring the stability of thin and medium back-up filters of the Newton-XMM EPIC camera
Abstract
We are conducting a measurement program on back-up filters of the XMM-Newton EPIC camera aimed at monitoring possible aging effects during the mission lifetime. One thin and one medium EPIC back-up filters have been stored since 1997 in an environment similar to that one of the flight filters (dry nitrogen box before launch, high vacuum after launch). The transmission of the two filters has been measured periodically in the 1900-10000 angstrom wavelength range where effects of aging would be clearly evident. The preliminary results, after 5 years of monitoring, show that a slight aging effect has occurred on both filters which, however, has no significant impact onto the EPIC calibration for the correct analysis of the X-ray astrophysical observations.
X-Ray and Gamma-Ray Telescopes and Instruments for Astronomy. Edited by Joachim E. Truemper, Harvey D. Tananbaum. Proceedings of the SPIE, Volume 4851, pp. 264-269 (2003).Mar 2003
2000
- The XACT facility at OAPA : ongoing projects and future developments
Abstract
Not Available
Memorie della Società Astronomia Italiana, Vol. 71, p.1127n/a 2000
1999
- Measurement of optical constants n and k of lexan and polyimide
Abstract
We present preliminary results on a program aimed at characterizing the optical properties of materials of potential usage in filters for soft x-ray detectors. In particular, we discuss a method that we have used to derive and model the refractive index n and the extinction coefficient k of thin plastic film materials. The method is based on best fit estimates of the parameters of a quanto- mechanical model describing k. The value of n is then evaluated using the Kramers-Kronig relationship. This method has provided accurate values of previously unknown optical constants of polyimide and lexan allowing to model the transmission of multilayer filters such as the aluminized polyimide filters of the HRC on board Chandra X-ray Observatory.
Proc. SPIE Vol. 3765, p. 805-815, EUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy X, Oswald H. Siegmund; Kathryn A. Flanagan; Eds.Oct 1999