Διερεύνηση της δυνατότητας συγκρότησης διάταξης XRF με χρήση μηχανής ακτίνων-Χ 200 kV

Γρίβας, Συμεών Ζ.; Grivas, Symeon Z.

dc.contributor.author	Γρίβας, Συμεών Ζ.	el
dc.contributor.author	Grivas, Symeon Z.	en
dc.date.accessioned	2018-09-05T08:41:46Z
dc.date.available	2018-09-05T08:41:46Z
dc.date.issued	2018-09-05
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/47518
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.15328
dc.rights	Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/gr/	*
dc.subject	Φθορισμός ακτίνων-Χ	el
dc.subject	Διάταξη XRF	el
dc.subject	Προσομοίωση Monte Carlo	el
dc.subject	Κώδικας PENELOPE	el
dc.subject	Ανιχνευτής BEGe	el
dc.subject	Ανιχνευτής Si-PIN	el
dc.subject	X-ray fluorescence	en
dc.subject	XRF arrangement	en
dc.subject	Monte Carlo simulation	en
dc.subject	PENELOPE code	en
dc.subject	BEGe detector	en
dc.subject	Si-PIN detector	en
dc.title	Διερεύνηση της δυνατότητας συγκρότησης διάταξης XRF με χρήση μηχανής ακτίνων-Χ 200 kV	el
heal.type	bachelorThesis
heal.classification	Φασματοσκοπία ακτίνων-Χ	el
heal.classification	X-ray Spectroscopy	en
heal.classificationURI	http://data.seab.gr/concepts/7f8d41503d21638090266a2d0d7e8a9cf22cd946
heal.classificationURI	http://data.seab.gr/concepts/7f8d41503d21638090266a2d0d7e8a9cf22cd946
heal.language	el
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2018-07-02
heal.abstract	Η παρούσα Διπλωματική Εργασία ασχολείται με θέματα τα οποία εμπίπτουν στη μελέτη της τεχνικής φθορισμού των ακτίνων-Χ (XRF), τεχνικής που εφαρμόζεται στο Εργαστήριο Πυρηνικής Τεχνολογίας του Εθνικού Μετσόβιου Πολυτεχνείου (ΕΠΤ-ΕΜΠ). Σκοπός της εργασίας αυτής ήταν η διερεύνηση της δυνατότητας συγκρότησης διάταξης XRF με χρήση μηχανής ακτίνων-Χ βιομηχανικής ραδιογραφίας. Οι υψηλές ενέργειες φωτονίων επιτρέπουν τη διέγερση της στιβάδας Κ των στοιχείων υψηλού ατομικού αριθμού και η ανίχνευση χαρακτηριστικών ακτίνων-Χ γίνεται σε μία περιοχή με λιγότερες παρεμβολές λόγω χαρακτηριστικών ακτίνων άλλων στοιχείων. Για τη διερεύνηση επιστρατεύθηκαν τεχνικές προσομοίωσης Monte Carlo, με χρήση του κώδικα PENELOPE, και πειραματικές τεχνικές.	el
heal.abstract	The X-ray fluorescence (XRF) technique is widely in use today for a fast, cheap, non-destructive elemental analysis of samples of environmental or other interest. In spite of the diffusion of this method, there have been made relatively few attempts to implement it for the excitation of the Kseries characteristic lines of heavy elements. A benefit that can arise from such an excitation is the detection of characteristic X-rays in the spectrum of the detector, found in an energy range that is, to a great extent, free from interference by other elements’ characteristic lines. The goal that was set for this diploma thesis was to investigate the capability to assemble an XRF array to perform this test, in the Nuclear Energy Department of the National Technical University of Athens (NED-NTUA). For this purpose, it was decided to use components that were at that moment available in the laboratory. In particular, an X-ray tube of 200 kV maximum high voltage, mainly used for industrial radiography purposes, along with two semiconductor detectors, that meet the requirements set, were utilised. One of the detectors, a Broad Energy Germanium detector (BEGe), was used to detect uranium, while the other one, a Si-PIN detector, to detect rare earth elements (REE). For this investigation were used, in essence, Monte-Carlo simulation techniques. The simulations’ goals were the XRF array modelling and the analysis of the effect of various operational, geometrical or extrinsic parameters in the results of the method. The outcome showed a dependency of the detectability of the element of interest on the sample excitation, as well as on other factors, for instance on the element concentration, the angle between various array elements, the beam collimator, the sample dimensions, the surrounding area and the conical beam aperture. Furthermore, the linear polarization of the exciting radiation, that can be achieved through two successive perpendicular reflections in space (triaxial geometry), exhibited a possibly significant impact on the results. Moreover, a simplification of the Si-PIN detector model was accomplished, achieving simulation acceleration, without important adverse effects in the precision of the quantitative results. Concurrently, the attempt to assemble the XRF array in the NED-NTUA was carried out, alongside test measurements. Most importantly, the main goals were set to be the reduction of high photon flux towards the detector, the decrease in scattered photons and the formation of a suitable excitation spectrum to irradiate the samples. Even though still in an early stage, the experimental results, are promising, as the detection of a gold sample has been successful. There are definitely challenges to cope with, in order for the array to become operational in the future and to be used for the detection of even heavier elements and for the elemental characterization of real samples. The conclusions that emerged from the simulations are expected to be of use in this effort.	en
heal.advisorName	Αναγνωστάκης, Μάριος	el
heal.committeeMemberName	Αναγνωστάκης, Μάριος	el
heal.committeeMemberName	Πετρόπουλος, Νικόλαος	el
heal.committeeMemberName	Ρούνη, Παναγιώτα	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Μηχανολόγων Μηχανικών. Τομέας Πυρηνικής Τεχνολογίας	el
heal.academicPublisherID	ntua
heal.numberOfPages	200 σ.
heal.fullTextAvailability	true