Background minimization issues for next generation hard X-ray focusing telescopes

Fioretti, Valentina (2011) Background minimization issues for next generation hard X-ray focusing telescopes, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Astronomia, 23 Ciclo. DOI 10.6092/unibo/amsdottorato/3858.
Documenti full-text disponibili:
[img]
Anteprima
Documento PDF (English) - Richiede un lettore di PDF come Xpdf o Adobe Acrobat Reader
Download (8MB) | Anteprima

Abstract

The hard X-ray band (10 - 100 keV) has been only observed so far by collimated and coded aperture mask instruments, with a sensitivity and an angular resolution lower than two orders of magnitude as respects the current X-ray focusing telescopes operating below 10 - 15 keV. The technological advance in X-ray mirrors and detection systems is now able to extend the X-ray focusing technique to the hard X-ray domain, filling the gap in terms of observational performances and providing a totally new deep view on some of the most energetic phenomena of the Universe. In order to reach a sensitivity of 1 muCrab in the 10 - 40 keV energy range, a great care in the background minimization is required, a common issue for all the hard X-ray focusing telescopes. In the present PhD thesis, a comprehensive analysis of the space radiation environment, the payload design and the resulting prompt X-ray background level is presented, with the aim of driving the feasibility study of the shielding system and assessing the scientific requirements of the future hard X-ray missions. A Geant4 based multi-mission background simulator, BoGEMMS, is developed to be applied to any high energy mission for which the shielding and instruments performances are required. It allows to interactively create a virtual model of the telescope and expose it to the space radiation environment, tracking the particles along their path and filtering the simulated background counts as a real observation in space. Its flexibility is exploited to evaluate the background spectra of the Simbol-X and NHXM mission, as well as the soft proton scattering by the X-ray optics and the selection of the best shielding configuration. Altough the Simbol-X and NHXM missions are the case studies of the background analysis, the obtained results can be generalized to any future hard X-ray telescope. For this reason, a simplified, ideal payload model is also used to select the major sources of background in LEO. All the results are original contributions to the assessment studies of the cited missions, as part of the background groups activities.

Abstract
Tipologia del documento
Tesi di dottorato
Autore
Fioretti, Valentina
Supervisore
Co-supervisore
Dottorato di ricerca
Scuola di dottorato
Scienze matematiche, fisiche ed astronomiche
Ciclo
23
Coordinatore
Settore disciplinare
Settore concorsuale
Parole chiave
X-ray background Monte Carlo
URN:NBN
DOI
10.6092/unibo/amsdottorato/3858
Data di discussione
11 Aprile 2011
URI

Altri metadati

Statistica sui download

Gestione del documento: Visualizza la tesi

^