12 th SYMPOSIUM OF THE HELLENIC NUCLEAR PHYSICS SOCIETY

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1 β γ α 12 th SYMPOSIUM OF THE HELLENIC NUCLEAR PHYSICS SOCIETY Ε. Ε. Π. Φ. NCSR Demokritos, Athens, May 10-11, 2002 Organising Committee Dr. S. V. Harissopulos Dr. P. Demetriou Dr. D. Bonatsos

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3 Στη µνήµη του Θέµη Παραδέλλη Aγαπηµένου Φίλου, Συναδέλφου, και Προέδρου της Ελληνικής Εταιρείας Πυρηνικής Φυσικής,

4 ρ. Νικηφόρος Θεµιστοκλής ΠΑΡΑ ΕΛΛΗΣ ( ) ιευθυντής Ερευνών Πρόεδρος της Ελληνικής Εταιρείας Πυρηνικής Φυσικής Ο Νικηφόρος Θεµιστοκλής Παραδέλλης γεννήθηκε στις 4 Ιουλίου του 1942 στο Κάιρο. Αποφοίτησε το 1965 µε το Πτυχίο του Φυσικού από τη Φυσικοµαθηµατική Σχολή του Πανεπιστηµίου Αθηνών. Στη συνέχεια µετέβη στον Καναδά όπου από το Πανεπιστήµιο του Saskatchewan πήρε το MASTER το 1967 και το PhD το Αφού εργάσθηκε για µικρό διάστηµα στον Καναδά, ανταποκρίθηκε στην πρόσκληση του Εργαστηρίου Επιταχυντού TANDEM του «ηµόκριτου» και ήλθε στην Ελλάδα., επιλέγοντας την θέση αυτή ανάµεσα σε άλλες δελεαστικές προτάσεις (π.χ. ΜΙΤ). Αφιέρωσε όλη του την ζωή ώστε να γίνει ο επιταχυντής TANDEM ένα διεθνώς αναγνωρισµένο και έγκυρο Εργαστήριο αλλά και φυτώριο νέων επιστηµόνων στον τοµέα της Πυρηνικής Φυσικής Ασχολήθηκε µε πολλούς τοµείς της επιστηµονικής έρευνας της πυρηνικής φυσικής, ξεκινώντας µε αυτόν της πυρηνικής φασµατοσκοπίας όπου ασχολήθηκε µε την µελέτη της δοµής διάφορων πυρήνων, αλλά και µε τη βελτίωση των µεθόδων ανάλυσης φασµατοσκοπικών δεδοµένων. Ανέπτυξε πρωτότυπες πειραµατικές διατάξεις και µεθοδολογίες για την µελέτη πυρηνικών αντιδράσεων που θεωρούνται κλειδιά για την κατανόηση της γένεσης και εξέλιξης των άστρων. Η συνεισφορά του στον τοµέα της Πυρηνικής Αστροφυσικής, το τελευταίο του ερευνητικό πεδίο, ήταν ιδιαίτερα σηµαντική. Πέρα από την διεθνώς αναγνωρισµένη ερευνητική δουλειά στο αντικείµενο αυτό, ο Θέµης Παραδέλλης ξεκίνησε το 1974 την σειρά των συνεδρίων Πυρηνικής Αστροφυσικής µε τίτλο Nuclei in the Cosmos που σύντοµα καθιερώθηκε στον διεθνή επιστηµονικό χώρο και σήµερα ισχύει ως το πιό σηµαντικό και έγκυρο ιεθνές Συνέδριο Πυρηνικής Αστροφυσικής. Πολύ νωρίς ο Θέµης Παραδέλλης αναγνώρισε την ανάγκη της εφαρµογής των αποτελεσµάτων της έρευνας στην κάλυψη κοινωνικών αναγκών. Έτσι, από το 1974 ασχολήθηκε και µε την εφαρµογή πυρηνικών και ατοµικών µεθόδων στην µικροανάλυση υλικών και συνεισέφερε σε τοµείς όπως η ιατρική έρευνα, η αρχαιοµετρία, η ανάλυση αερολυµάτων κ.α. Ο εργασίες του στους ανωτέρω τοµείς είναι πρωτοποριακές για την εποχή τους και σήµερα αποτελούν εργασίες αναφοράς. Ο Θέµης Παραδέλλης επέβλεψε πάνω από δέκα διδακτορικές διατριβές µεταφέροντας µε αξιοζήλευτη θέρµη τις γνώσεις του σε νέους επιστήµονες. Το 1999 εκλέχτηκε Πρόεδρος της Ελληνικής Εταιρείας Πυρηνικής Φυσικής.

5 β γ α 12th SYMPOSIUM OF THE HELLENIC NUCLEAR PHYSICS SOCIETY NCSR Demokritos, Athens, May 10-11, 2002 Ε. Ε. Π. Φ. Organising Committee : S. Harissopulos, P. Demetriou, D. Bonatsos SCIENTIFIC PROGRAMME FRIDAY Registration Opening by the Governing Board of The Hellenic Nuclear Physics Society and The Organizing Committee SESSION I Chair: M. Grypeos (Aristotle University of Thessaloniki) G.S. Anagnostatos (NCSR Demokritos ) On the nature of superdeformation G. A. Lalazissis (Aristotle University of Thessaloniki) Proton drip line nuclei in the Relativistic Hartree-Bogoliubov model P. Papakonstantinou (University of Athens) Multipole response of O and Ca isotopes in a self-consistent continuum RPA calculation S. Athanassopoulos (University of Athens) Neutron separation energies from nuclear mass systematics using neural networks D. Bonatsos (NCSR Demokritos ) Quantum groups in nuclear spectra and in metal clusters Coffee break SESSION II Chair: C.A. Kalfas (NCSR Demokritos ) S. Harissopulos (NCSR Demokritos ) A systematic study of proton capture reactions in the Se-Sn region relevant to p-process nucleosynthesis M. Kokkoris (NCSR Demokritos ) Cross sections of the 89 Y(p,γ) reaction relevant to the p-process S. Galanopoulos (NCSR Demokritos ) Cross sections of proton capture reactions of Sr isotopes G. Kriembardis (NCSR Demokritos ) Cross section measurements of 78 Se(p, γ) and 80 Se(p,γ) reactions G. Perdikakis (NCSR Demokritos ) Statistical model calculations of the 232 Th(n,2n) reaction M. Frangopoulou (Aristotle University of Thessaloniki) Μια νέα διάταξη για τη µεταστοιχείωση στοιχείων Lunch and Coffee SESSION III Chair: L. D. Skouras (NCSR Demokritos ) N. G. Nicolis (University of Ioannina) Neutron excess dependence of fusion barrier parameters P. Demetriou (NCSR Demokritos ) Improved global α optical model potentials at low energies P. K. Papachristou (University of Athens) Tunneling from oscillating barriers in nuclei Ch. C. Moustakidis (Aristotle University of Thessaloniki) Bose-Einstein condensation of correlated atoms in a trap T.E. Liolios (Hellenic Merchant Marine Academy) Plasma screening effects in resonant thermonuclear reactions of the rp process General Assembly of the Hellenic Nuclear Physics Society

6 SATURDAY SESSION IV Chair: E. Mavrommatis (University of Athens) N. Giokaris (University of Athens) Potential of antiprotons for imaging and radiotherapy G. Loudos (University of Athens) Ανάπτυξη τοµογραφικής γ-κάµερας υψηλής διακριτικής ικανότητας V. Spanoudaki (University of Athens) Μελέτη διακριτικής ικανότητας γ-κάµερας SPECT A. G. Karydas (NCSR Demokritos ) X-Ray Fluorescence Analysis of a Gold Ibex and other Artifacts from Akrotiri Ch. Zarkadas (NCSR Demokritos ) Development of X-ray fluorescence methods by use of a Mo X-ray tube and their application in the case of biological samples S. Kossionides (NCSR Demokritos ) Analysis of ancient glass using ion beams and related techniques Coffee break SESSION V Chair: S. E. Massen (Aristotle University of Thessaloniki) C.G. Koutroulos (Aristotle University of Thessaloniki) Information on the size and other quantities of Λ-orbitals in hypernuclei from experimental Λ-energies Th. Petridou (Aristotle University of Thessaloniki) A simplified response function formalism for medium-heavy Λ hypernuclei T.S. Kosmas (University of Ioannina) The Deformed Hartree-Fock method in the study of the semileptonic processes in nuclei V. Ch. Chasioti (University of Ioannina) Nuclear matrix elements for exclusive transitions of semi-leptonic processes N. Panagiotides (University of Ioannina) Systematic study of the muon-nucleus overlap integrals for various procesess in muonic atoms L.A. Kaliambos (Inst. of Larissa) Nuclear Structure is governed by the fundamental laws of electromagnetism Lunch and Coffee SESSION VI Chair: R. Vlastou (National Technical University of Athens) C. A. Papachristodoulou (University of Ioannina) On the ph-dependent strontium adsorption by Al-PILCs, impregnated with carboxylate groups of various acid strengths A. G. Karydas (NCSR Demokritos ) X-Ray spectrometric studies using thin silicon crystals. Advantages and applications G. Kalliabakos (NCSR Demokritos ) Copper and sulphur depth profile in patina layers using NRA and RBS T.E. Liolios (Hellenic Merchant Marine Academy) Effects of radiological weapons END OF THE SYMPOSIUM

7 Abstracts following the order in the programme

8 On the nature of superdeformation G.S. Anagnostatos Institute of Nuclear Physics, NCSR Demokritos, Aghia Paraskevi, Athens

9 ÈÖÓØÓÒ Ö Ô Ð Ò ÒÙÐ Ò Ø Ê Ð Ø Ú Ø À ÖØÖ ¹ Ó ÓÐ Ù ÓÚ ÑÓ Ð ÓÖ Ó º Ä Ð Þ Ô ÖØÑ ÒØ Ó Ì ÓÖ Ø Ð È Ý Ö ØÓØÐ ÍÒ Ú Ö ØÝ Ó Ì ÐÓÒ Ê¹ ½¾ Ì ÐÓÒ Ö Ì Ê Ð Ø Ú Ø À ÖØÖ Ó ÓÐ Ù ÓÚ ÊÀ µ Ø ÓÖÝ ÔÔÐ ØÓ Ø ¹ Ö ÔØ ÓÒ Ó ÖÓÙÒ ¹ Ø Ø ÔÖÓÔ ÖØ Ó ÔÖÓØÓÒ¹Ö Ó ¹ ÒÙÐ º Ì ÑÓ Ð ÔÖ Ø Ø ÐÓ Ø ÓÒ Ó Ø ÔÖÓØÓÒ Ö Ô¹Ð Ò Ø ÖÓÙÒ ¹ Ø Ø ÕÙ ÖÙÔÓÐ ¹ ÓÖÑ Ø ÓÒ Ò ÓÒ ¹ÔÖÓØÓÒ Ô Ö Ø ÓÒ Ò Ö Ø Ò ÝÓÒ Ø Ö Ô¹Ð Ò Ø ÓÖÑ Ò Ð ¹Ô ÖØ Ð ÓÖ Ø Ð ÓÙÔ Ý Ø Ó Ú Ð Ò ÔÖÓØÓÒ Ò Ø ÓÖÖ ÔÓÒ Ò Ô ØÖÓ ÓÔ ØÓÖ º Ì Ö ÙÐØ Ó ÙÐÐÝ Ð ¹ÓÒ Ø ÒØ ÊÀ ÐÙÐ Ø ÓÒ Ö ÓÑÔ Ö Û Ø ÜÔ Ö Ñ ÒØ Ð Ø ÓÒ ÓÖÑ Ò ØÖ Ò Ø ÓÒ Ð ÔÖÓØÓÒ Ñ ØØ Ö Ò Ø ÔÖ Ø ÓÒ Ó Ú Ö ÓÙ Ñ ÑÓ Ð º ½

10 ÅÍÄÌÁÈÇÄ Ê ËÈÇÆË Ç Ç Æ ÁËÇÌÇÈ Ë ÁÆ Ë Ä ¹ ÇÆËÁËÌ ÆÌ ÇÆÌÁÆÍÍÅ ÊÈ Ä ÍÄ ÌÁÇÆ ÈºÈ Ô ÓÒ Ø ÒØ ÒÓÙ º Å ÚÖÓÑÑ Ø Âº Ï Ñ È Ý Ô ÖØÑ ÒØ Ú ÓÒ Ó ÆÙÐ Ö Ò È ÖØ Ð È Ý ÍÒ Ú Ö ØÝ Ó Ø Ò Ê¹½ ½ Ø Ò Ö ÁÒ Ø ØÙØ Ó ÆÙÐ Ö È Ý Ì Ò Ð ÍÒ Ú Ö ØÝ ÖÑ Ø Ø Ë ÐÓ ÖØ Ò ØÖº ¹ ¾ ÖÑ Ø Ø ÖÑ ÒÝ Ì Ô Ý Ó ÒÙÐ Ö ÖÓÑ Ø Ð ØÝ ÙÒ Ö ØÙ Ý Ò ÔÖ ÒØ Ò ÙØÙÖ Ö Ó Ø Ú ÓÒ Ñ Ð Ø ÔÖ ÒØ ÒØ Ö Ø Ò ÒÓÚ Ð ØÙÖ º ÁÒ Ø Ð Ø Û Ý Ö Ø Ø ÓÖ Ø Ð Ò ÜÔ Ö Ñ ÒØ Ð ØÙ Ý Ó Ø ÑÙÐØ ÔÓÐ Ö ÔÓÒ Ó Ú Ö ÓÙ Ù ÒÙÐ Ð Ø Ò Ñ Ùѹ ÚÝ ÓÒ µ Ø ÖØ Ñ Ò ØÓ ÐÐÙÑ Ò Ø ÓÑ Ó Ø «Ø ÓÒ Ø Ö ÔÓÒ Ó Ø Ü ÔÖÓØÓÒ ÓÖ Ò ÙØÖÓÒ ÒÙÑ Ö ÓÖ Ü ÑÔÐ Ø ÓÒØÖ ÙØ ÓÒ Ò ½ ¾ µº ÁÒ Ø ÛÓÖ Ð ¹ÓÒ Ø ÒØÓÒØ ÒÙÙÑ À ¹ÊÈ ÐÙÐ Ø ÓÒ ÖÖ ÓÙØ ÓÖ Ø Ó Ð Ö ÑÓÒÓÔÓÐ Ò ÕÙ ÖÙÔÓÐ Û ÐÐ Ø ÓÚ ØÓÖ ÔÓÐ Ö ÔÓÒ Ó Ú Ò Ç Ò ÓØÓÔ Ù Ò Ù Ø Ð Ë ÝÖÑ ÓÖ Ô Ö Ñ ØÖ Þ ¹ Ø ÓÒ Ò ÓÖ Ö ØÓ ØÙ Ý Ø «Ø Ó Ö Ù ÐÐÝ Ú ÖÝ Ò Ø Ò ÙØÖÓÒ ÒÙÑ Öº ÇÒ Ó ÓÙÖ Ñ ØÓ Ù ÕÙ ÒØÐÝ Ô Ö ÓÖÑ ÓÒ ¹ÓÖ Ö ÊÈ ÐÙÐ Ø ÓÒ º Ì ÓÖÖ ÔÓÒ Ò Ñ Ø Ó ÒÐÙ Ò Ø ÓÒØ ÒÙÙÑ Ø ÔÖ ÒØ ÙÒ Ö Ú ÐÓÔÑ Òغ Ê Ö Ò ½º ÈÖÓ Ò Ó Ø ÌÓÔ Ð ÓÒ Ö Ò ÓÒ ÒØ Ê ÓÒ Ò Î Ö ÒÒ Å Ý ½½¹½ ½ ÆÙк È Ý º ½ µº ¾º ÈÖÓ Ò Ó Ø ÌÓÔ Ð ÓÒ Ö Ò ÓÒ ÒØ Ê ÓÒ Ò Ç ÂÙÒ ½¾¹½ ¾¼¼¼ ÆÙк È Ý º ¾¼¼½µº º º º ÖØ Ò Ëº ºÌ È Ý º Ê Ôº ½ ½ µ ½¾ º ÖØ Ò ÓÑÔÙØ Ø ÓÒ Ð ÆÙÐ Ö È Ý Á ¹ ÆÙÐ Ö ËØÖÙØÙÖ º ÃºÄ Ò Ò Âº ºÅ ÖÙ Ò Ò Ëº ºÃÓÓÒ Ò ËÔÖ Ò Ö ÖÐ Ò ½ ½µ Ôº¾ º º ˺ ÖÓÞ Þ ËºÆ Þ ÂºËÔ Ø Ò ÂºÏ Ñ È Ý º Ê Ôº ½ ½ ¼µ ½º

11 Neutron separation energies from nuclear mass systematics using neural networks S. Athanassopoulos a, E. Mavrommatis a, K. A. Gernoth b and J.W. Clark c a Physics Department, Division of Nuclear and Particle Physics University of Athens, GR Athens, Greece b Department of Physics, UMIST, P.O. Box 88 Manchester M60, 1QD, United Kingdom c McDonnell Center for the Space Sciences and Department of Physics Washington University, St. Louis, Missouri 63130, USA Statistical modeling of data sets by neural network techniques is offered as an alternative to traditional semi-empirical approaches to global modeling of nuclear properties. There is need for such systematics driven by fundamental investigations of nuclear structure far from stability, conducted at heavy ion and radioactive ion beam facilities. There is also great current interest from the perspective of astrophysics and of nuclear technology. In this work we evaluate the one and two neutron separation energies based on global models for the masses of nuclides developed with the use of neural networks[1] and compare them with the experimental ones as given by Audi at Atomic Mass Data Center web site [2]. Our work on masses is a continuation of the work reported in ref. [3]. We have used enriched data sets together with a novel training algorithm and various coding schemes to achieve high performance both in learning and prediction. Our performance is comparable to the best of other evaluations of separation energies based on global models for the masses of nuclides (like those of Möller et al. [4] and Pearson et al. [5] that are rooted in conventional Hamiltonian theory), whereas the number of parameters is larger. Neural network modeling, as well as other statistical strategies based on new algorithms for artificial intelligence, may prove to be a useful asset in the further exploration of nuclear phenomena far from stability. References 1. S. Athanassopoulos, E. Mavrommatis, K. A. Gernoth, and J. W. Clark, Explorations of nuclear mass systematics using neural networks, in submission 2. (files rct1_exp.mas95 and rct2_exp.mas95 ) 3. S. Gazula, J. W. Clark and H. Bohr, Nucl. Phys. A540 (1992) 1 ; K. A. Gernoth, J. W. Clark, J. S. Prater and H. Bohr, Phys. Lett. B300 (1993) 1 ; K. A. Gernoth and J. W. Clark, Comp. Phys. Commun. 88 (1995) 1 ; E. Mavrommatis, S. Athanassopoulos, K. A. Gernoth, and J. W. Clark, Condensed Matter Theories, Vol. 15, edited by G. S. Anagnostakos et al. (Nova Science Publishers, N.Y. 2000) P. Möller, J. R. Nix, W. D. Myers, and W. J. Swiatecki, At. Data Nucl. Data Tables 59 (1995) 186 and references therein 5. S. Goriely, F. Tondeur and J. M. Pearson, At. Data Nucl. Data Tables 77 (2001) 311

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14 ÖÓ Ø ÓÒ Ó Ø Ô µ Ö Ø ÓÒ Ö Ð Ú ÒØ ØÓ Ø Ô ÔÖÓ ½ Ⱥ Ì Ö Åº ÃÓ ÓÖ º Ë Ö Ø Èº Ñ ØÖ Ó٠˺ Ð ÒÓÔÓÙÐÓ º º à ÖÝ º Ö Ëº À Ö ÓÔÙÐÓ Ò Ìº È Ö ÐÐ ÁÒ Ø ØÙØ Ó ÆÙÐ Ö È Ý Æ Ø ÓÒ Ð ÒØÖ ÓÖ Ë ÒØ Ê Ö ÑÓ Ö ØÓ ÈÇ ¼¾¾ ½ º½¼ È Ö Ú Ø Ò Ö º ʺ ÃÙÒÞ Ò ÂºÏº À ÑÑ Ö ÁÒ Ø ØÙØ ĐÙÖ ËØÖ Ð ÒÔ Ý ÍÒ Ú Ö ØĐ Ø ËØÙØØ ÖØ ¼ ËØÙØØ ÖØ ÖÑ Òݺ Ì ÖÓ Ø ÓÒ Ó Ø Ô µ ¼ Ö Ö Ø ÓÒ Û Ø ÖÑ Ò Ø Ô ½º ¹ º Å Î Ú Ò Ð ¹ ÒØ Ö Ø Ñ ÙÖ Ñ ÒØ ÖÖ ÓÙØ Ý Ñ Ò Ó Æ Á ÙÑÑ Ò Ø ØÓÖ Û ÐÐ Ú Ò ÙÐ Ö ØÖ ÙØ ÓÒ Ñ ÙÖ Ñ ÒØ Ù Ò Ò ÖÖ Ý Ó ÀÈ Ø ØÓÖ Û Ø ½¼¼± Ö Ð Ø Ú Æ Òݺ Ì Ö ÙÐØ Ò ÖÓ Ø ÓÒ Ú ÖÝ ÖÓÑ ¼º ØÓ Ñ º ØÖÓÔ Ý Ð Ë ØÓÖ Ò Ö Ø ÓÒ Ö Ø Ú Ð Ó Ò Ö Ú º ÓÓ Ö Ñ ÒØ ØÛ Ò Ø ÜÔ Ö Ñ ÒØ Ð Ö Ø Ò Ò Ø ÔÖ Ø ÓÒ Ó Ø Ø Ø Ð Ø ÓÖÝ Ò ÓÙÒ º ½ ÏÓÖ ÙÔÔÓÖØ Ý Æ ÌÇ Ê ÈÖÓ Ö ÑÑ ÓÒØÖº ÆÓº Ê ½¼

15 ÖÓ Ø ÓÒ Ó ÔÖÓØÓÒ ÔØÙÖ Ö Ø ÓÒ Ó ËÖ ÓØÓÔ ½ ˺ Ð ÒÓÔÓÙÐÓ Èº Ñ ØÖ Ó٠ź ÃÓ ÓÖ º ÃÖ Ñ Ö Ò Ëº À Ö ÓÔÙÐÓ ÁÒ Ø ØÙØ Ó ÆÙÐ Ö È Ý Æ Ø ÓÒ Ð ÒØÖ ÓÖ Ë ÒØ Ê Ö ÑÓ Ö ØÓ ÈÇ ¼¾¾ ½ º½¼ È Ö Ú Ø Ò Ö º ʺ ÃÙÒÞ Åº Ý Ò ÂºÏº À ÑÑ Ö ÁÒ Ø ØÙØ ĐÙÖ ËØÖ Ð ÒÔ Ý ÍÒ Ú Ö ØĐ Ø ËØÙØØ ÖØ ÐÐÑ Ò Ö Ò ¼ ËØÙØØ ÖØ ÖÑ Òݺ ݺ ÝĐÙÖ Ý º ĐÙÐĐÓÔ Ò º ËÓÑÓÖ ÁÒ Ø ØÙØ Ó ÆÙÐ Ö Ê Ö Ó Ø ÀÙÒ Ö Ò ÑÝ Ó Ë Ò ÌÇÅÃÁµ Ñ Ø Ö ½» ¼¼½ Ö Ò ÀÙÒ ÖÝ Ëº ÓÖ ÐÝ ÁÒ Ø ØÙØ ³ ØÖÓÒÓÑ Ø ³ ØÖÓÔ Ý ÕÙ ÍÒ Ú Ö Ø Ä Ö ÖÙÜ ÐÐ ÑÔÙ Ð ÈÐ Ò È¾¾ ½¼ ¼ ÖÙ Ð Ð ÙѺ ÖÓ Ø ÓÒ Ñ ÙÖ Ñ ÒØ Ó Ø ÔÖÓØÓÒ ÔØÙÖ Ö Ø ÓÒ Ó Ø ËÖ ËÖ Ò ËÖ ÓØÓÔ Û Ö ÖÖ ÓÙØ Ø Ò Ö Ô ½º ¹ Šκ Ø Ô º Å Î Ò ÖÖ Ý Ó ÀÈ Ø ØÓÖ Û Ø ½¼¼± Ö Ð Ø Ú Æ ÒÝ Ð Û Ø Ç ÒØ ÐÐ ØÓÖ ÓÖ ÓÑÔØÓÒ ÖÓÙÒ ÙÔÔÖ ÓÒ Û Ù Û Ö Ø Ô º Å Î Ø Ñ ÙÖ ¹ Ñ ÒØ Û Ö Ô Ö ÓÖÑ Ý Ñ Ò Ó ÓÒ ÀÈ Ø ØÓÖ Ó ¼± Ö Ð Ø Ú Æ Òݺ ÓÖ Ø ËÖ Ô µ Ò ËÖ Ô µ Ö Ø ÓÒ ØÓØ Ð ÖÓ Ø ÓÒ Ö Ò Ò ÖÓÑ ¼º ß Ñ Û Ö ÓÙÒ º Ì Ø Ò ÐÝ Ó Ø ËÖ Ô µ Ö Ø ÓÒ Ò ÔÖÓ Ö º ÖÓ Ø ÓÒ Ú Ð Ó Ò ÐÙÐ Ø Ý Ñ Ò Ó Ø Ø Ø Ø Ð ÑÓ Ð Ó ÅÇË̺ Ú ÖÝ ÓÓ Ö Ñ ÒØ ØÛ Ò Ø ÜÔ Ö Ñ ÒØ Ð Ø Ò Ø Ø ÓÖ Ø Ð ÔÖ Ø ÓÒ Ò ÓÙÒ º ½ ÏÓÖ ÙÔÔÓÖØ Ý Æ ÌÇ Ê ÈÖÓ Ö ÑÑ ÓÒØÖº ÆÓº Ê ½¼

16 ÖÓ Ø ÓÒ Ñ ÙÖ Ñ ÒØ Ó Ø Ë Ô µ Ö Ò ¼ Ë Ô µ ½ Ö Ö Ø ÓÒ ½ º ÃÖ Ñ Ö Ëº Ð ÒÓÔÓÙÐÓ º Ⱥ Ñ ØÖ ÓÙ Ò Ëº À Ö ÓÔÙÐÓ ÁÒ Øº Ó ÆÙÐ Ö È Ý Æ ËÊ ÑÓ Ö ØÓ ½ º½¼ È Ö Ú Ø Ò Ö º ź Ý Êº ÃÙÒÞ Ò ÂºÏº À ÑÑ Ö ÁÒ Ø ØÙØ ĐÙÖ ËØÖ Ð ÒÔ Ý ÍÒ Ú Ö ØĐ Ø ËØÙØØ ÖØ ¼ ËØÙØØ ÖØ ÖÑ Òݺ ݺ ÝĐÙÖ Ý º ĐÙÐÓÔ Ò º ËÓÑÓÖ ÁÒ Ø ØÙØ Ó ÆÙÐ Ö Ê Ö ÌÇÅÃÁµ Ö Ò ÀÙÒ ÖÝ Êº ÂÙÐ Ò Ô ÖØÑ ÒØ Ó È Ý ÍÒ Ú Ö ØÝ Ó ÂÝÚĐ ÝÐĐ ÈÇ ÂÝÚĐ ÝÐ ÒÐ Ò ÁÒ Ñ ÖÓ Ø ÓÒ Ñ ÙÖ Ñ ÒØ Ó Ø Ë Ô µ Ö Ò ¼ Ë Ô µ ½ Ö Ö ¹ Ø ÓÒ Ú Ò ÖÖ ÓÙØ Ø Ô ½º ¹ º Å Î Ý Ù Ò Æ ÒÝ ÀÈ Ø ¹ ØÓÖ Û Ø Ç Ð ÓÖ ÓÑÔØÓÒ ÖÓÙÒ ÙÔÔÖ ÓÒº ÔÖ Ð Ñ Ò ÖÝ Ò ÐÝ Ý Ð ØÓØ Ð ÖÓ Ø ÓÒ Ö Ò Ò ÖÓÑ ½¼ ØÓ Ñ º Ý Ñ Ò Ó Ø Ø Ø Ø Ð ÓÑÔÓÙÒ ÒÙÐ Ù Ø ÓÖÝ Ó À Ù Ö¹ ÖÓ Ø ÓÒ Ú Ð Ó Ò ÐÙÐ Ø º ÓÑÔ Ö ÓÒ ØÛ Ò ÜÔ Ö Ñ ÒØ Ð Ø Ò Ø ÓÖ Ø Ð ÔÖ Ø ÓÒ ÔÖ ÒØ º ½ ÏÓÖ ÙÔÔÓÖØ Ý Æ ÌÇ Ê ÈÖÓ Ö ÑÑ ÓÒØÖº ÆÓº Ê ½¼

17 Statistical model calculations of the 232 Th(n,2n) reaction D. Karamanis a,*, S. Andriamonje e, P.A. Assimakopoulos a, G. Doukellis d, D.A. Karademos a, A. Karydas b, M. Kokkoris b, S. Kossionides b, N. Nicolis a, A. Pakou a, C. Papachristodoulou a, C. Papadopoulos c, N. Patronis a, P. Pavlopoulos, G. Perdikakis c, R. Vlastou c for the APC Consortium and the n-tof collaboration a Department of Physics, The University of Ioannina, Ioannina, Greece b Institute of Nuclear Physics, NCSR Demokritos, Aghia Paraskevi, Greece c National Technical University of Athens, Athens, Greece d Institute of Technical Education, Athens, Greece e CEA-DSM/DAPNIA Saclay France Abstract On the context of the Cern n_tof collaboration the 232 Th(n,2n) 231 Th reaction cross section has been measured relative to the 56 Fe(n,p) 56 Mn and 27 Al(n,α) 24 Na reaction cross sections by the activation method for neutron energies up to 11 MeV. The neutrons were produced via the 2 H(d,n) reaction using a deuterium filled gas-cell, at the 5.5MV TANDEM Accelerator of NCSR Demokritos. In addition to the experimental work, theoretical Statistical model calculations have been performed using the computer code STAPRE/F. The code STAPRE is designed to calculate energy averaged cross sections for particle induced nuclear reactions with several emitted particles and gamma rays under the assumption of sequential evaporation. For the first evaporation step preequilibrium emission is taken into account while population of states resulting from the first equilibrium evaporation step is calculated using the Hauser-Feschbach theory. Fission process competition is also taken into account in the evaporation steps. Sensitive parameters for the calculation, like level density parameters, have been adopted after fitting experimental data for the competing (n,f) reaction. The results are being compared to the experimental data. * Corresponding author. Tel.: ; fax: ; dkaraman@cc.uoi.gr

18 Μια νέα διάταξη για τη µεταστοιχείωση στοιχείων Μ. Φραγκοπούλου Αριστοτέλειο Πανεπιστήµιο Θεσσαλονίκης

19 Æ ÙØÖÓÒ Ü Ô Ò Ò Ó Ù ÓÒ ÖÖ Ö Ô Ö Ñ Ø Ö Æº º Æ ÓÐ Ô ÖØÑ ÒØ Ó È Ý ÍÒ Ú Ö ØÝ Ó ÁÓ ÒÒ Ò ÁÓ ÒÒ Ò ½½¼ Ö Ì Ò ÙØÖÓÒ Ü Ô Ò Ò Ó ÚÝ ÓÒ Ù ÓÒ ÖÖ Ö Ô Ö Ñ Ø Ö ÒÚ Ø Ø Ù Ý ÔÖ Ø ÓÒ Ó «Ö ÒØ ÚÝ ÓÒ ÔÓØ ÒØ Ð º Ï Ú ÐÓÔ Ô Ö Ñ ØÖ Þ Ø ÓÒ ÓÖ Ø Ù ÓÒ ÖÖ Ö Ø Ò Ö Ù Û Ü¹ ÔÐ ØÐÝ ÒÚÓÐÚ Ø ÒØÖ Ò ÒÒ Ð Ñ ÝÑÑ ØÖÝ Ò Ò ÙØÖÓÒ Ü Ó Ø ÔÖÓ Ø Ð Ò Ø Ö Øº Ì Ú ÐÓÔ ÜÔÖ ÓÒ Ö ÔÖÓ Ù Ø ÓÖ Ø Ð ÖÖ Ö Ô Ö Ñ Ø Ö Û Ø Ò ¼º¾± Û Ö ÔÖ ÒØ ÑÔÖÓÚ Ñ ÒØ ÓÚ Ö ÔÖ Ú ÓÙ Ô Ö Ñ ØÖ Þ Ø ÓÒ º ÙÖØ ÖÑÓÖ Ø Ý ÔÖÓÚ Ñ Ò ØÓ Ø ÑÔÓÖØ Ò Ó Ø Ò ÙØÖÓÒ Ü Ö Ó Ö ÓÑ ÑÔÐ Ý ÔÓØ Ò¹ Ø Ðº ÔÔÐ Ø ÓÒ Ó Ø ÜÔÖ ÓÒ ØÓ Ý Ø Ñ Ø Ó ÜÔ Ö Ñ ÒØ Ð ÖÖ Ö Ô Ö Ñ Ø Ö Û ÐÐ Ù º ½

20 ÁÑÔÖÓÚ ÐÓ Ð «ÓÔØ Ð ÑÓ Ð ÔÓØ ÒØ Ð Ø ÐÓÛ Ò Ö Èº Ñ ØÖ ÓÙ ÁÒ Ø ØÙØ Ó ÆÙÐ Ö È Ý Æ ËÊ ÑÓ Ö ØÓ ½ º½¼ È Ö Ú Ø Ò Ö Å ÒÝ ÒÙÐ Ö ØÖÓÔ Ý ÔÔÐ Ø ÓÒ ÒÚÓÐÚ Ö Ø Ú «¹Ô ÖØ Ð ÔØÙÖ «¹ Ý Ò «¹Ô ÖØ Ð ØÖ Ò Ö Ö Ø ÓÒ º Ì ÓÖ Ø Ð Ø Ñ Ø Ó Ø ÓÖÖ ÔÓÒ Ò Ö ¹ Ø ÓÒ Ö Ø Û Ø Ò Ø Ö Ñ ÛÓÖ Ó Ø Ø Ø Ø Ð ÑÓ Ð Ó À Ù Ö¹ Ö Ñ Ò ÐÝ ÙÒ ÖØ Ò Ù ØÓ Ø ÔÓÓÖ ÒÓÛÐ Ó Ø «¹ÒÙÐ Ù ÓÔØ Ð ÑÓ Ð ÔÓØ ÒØ Ð ¹ Ô ÐÐÝ Ø ÐÓÛ Ò Ö Ö ÐÓÛ Ø ÓÙÐÓÑ ÖÖ Öº ÁÒ Ø ÔÖ ÒØ Ô Ô Ö Û ÔÖÓÔÓ Ò Û ÐÓ Ð «¹ÓÔØ Ð ÔÓØ ÒØ Ð Ø Ø Ø ÒØÓ ÓÙÒØ Ø ØÖÓÒ Ò Ö Ý Ô Ò Ò Ò ÒÙÐ Ö ØÖÙØÙÖ «Ø Ø Ø Ö Ø Ö Þ Ø ÐÔ ¹ÒÙÐ Ù ÒØ Ö Ø ÓÒº Ì Ö Ð Ô ÖØ Ó Ø ÔÓØ ÒØ Ð ÐÙÐ Ø Ù Ò ÓÙ Ð ¹ ÓÐ Ò ÔÖÓ ÙÖ ÓÚ Ö Ø Å Ã «Ø Ú ÒÙÐ ÓÒ¹ÒÙÐ ÓÒ ÒØ Ö Ø ÓÒº ÏÓÓ ¹Ë ÜÓÒ ÔÓØ ÒØ Ð Ù ÓÖ Ø Ñ Ò ÖÝ ÔÓØ Ò¹ Ø Ð Û Ö ÒÓÛ Ò Û Ô Ö Ñ ØÖ Þ Ø ÓÒ ÒØÖÓ Ù ØÓ Ö Ø Ò Ö Ý Ô Ò Ò º Ì Ö ÔÓØ ÒØ Ð Ö Ú ÐÓÔ ÓÒ Û Ø ÔÙÖ ÐÝ ÚÓÐÙÑ ÓÖÔØ ÓÒ ÓÒ Û Ø ÚÓÐÙÑ ÔÐÙ ÙÖ ÓÖÔØ ÓÒ Ò Ò ÐÐÝ ÓÒ Û Ö Ò Ø ÓÒ ØÓ ÚÓÐÙÑ Ò ÙÖ ¹ ÓÖÔØ ÓÒ Ø Ô Ö Ú ÓÒØÖ ÙØ ÓÒ Ó Ø Ò ÖÓÑ Ø Ô Ö Ú Ö Ð Ø ÓÒ Ö ÒÐÙ º Ì Ø Ö ÔÓØ ÒØ Ð ÓÒ Ö Ö Ð ØÓ Ö ÔÖÓ Ù Ø ÙÐ Ó ÜÔ Ö Ñ ÒØ Ð Ø ÓÒ «µ «Òµ «Ôµ Ò Ò «µ Ö Ø ÓÒ Û ÐÐ Ø Ü Ø Ò Ð Ø ØØ Ö Ò Ø Ø Ò Ö Ó Ö Ð Ú Ò ØÓ ØÖÓÔ Ý Ð ÔÔÐ Ø ÓÒ º ÀÓÛ Ú Ö Û Ò ÓÒ Ö Ò Ö Ø ÓÒ Ö Ø ÓÖ ÒÙÐ Ò Ø ÜÔ Ö Ñ ÒØ ÐÐÝ ÙÒ ÜÔÐÓÖ Ñ Ö ÓÒ Ú Ø ÓÒ Û Ø Ò ØÓÖ Ó ½¼ Ö ÓÙÒ º Ì ÙÒ ÖØ ÒØ Ö Ñ ÒÐÝ Ù ØÓ Ø ÆÙÐØÝ Ò ÓÒ ØÖ Ò Ò Ø «Ù Ò Ó Ø Ñ Ò ÖÝ ÔÓØ ÒØ Ð ÖÓÑ Ò ÐÝ Ó Ü Ø Ò ÜÔ Ö Ñ ÒØ Ð Ø º

21 ÌÙÒÒ Ð Ò ÖÓÑ Ç ÐÐ Ø Ò ÖÖ Ö Ò ÆÙРȺ ÃºÈ È ÀÊÁËÌÇÍ ½ ºÃ ÌÁ ÇÊÁ ½ κ ÇÆËÌ ÆÌÇÍ ÁË ¾ º ú Á ÃÇÆÇË ½ ºÅ ÎÊÇÅÅ ÌÁË ½ ½ Ô ÖØÑ ÒØ Ó È Ý ÍÒ Ú Ö ØÝ Ó Ø Ò È Ò Ô Ø Ñ ÓÔÓÐ Ø Ò Ê ½ ½ ¾ Ô ÖØÑ ÒØ Ó È Ý Æ Ø ÓÒ Ð Ì Ò Ð ÍÒ Ú Ö ØÝ Ó Ø Ò Ó Ö ÓÙ ÑÔÙ Ø Ò Ê ½ ¼ ØÖ Ø ÁÒ Ø ÛÓÖ Û ØÙ Ý ÓÑ Ô Ø Ó Ø Ð Ð Ò ÕÙ ÒØÙÑ ÝÒ Ñ Ó ØÙÒ¹ Ò Ð Ò Ø ÖÓÙ Ó ÐÐ Ø Ò ÖÖ Ö ½ º Ì Ø Ñ ¹ Ô Ò Ò Ó Ø ÔÓØ ÒØ Ð ÜÔÐ ØÐÝ Ø Ò ÒØÓ ÓÙÒغ ÁÒØ Ö Ø Ò ÓÒÐÙ ÓÒ Ö Ö ÛÒ ÓÖ Ø Ò Ö Ý Ô Ò Ò Ó Ø ØÖ Ò Ñ ÓÒ Ó Æ ÒØ ÓÑÔ Ö Ò Ø Ð Ð Ò ÕÙ ÒØÙÑ Ñ Ò Ð Ö ÙÐØ º Ï Ð Ó ØÙ ÝØ Ø Ñ Ô Ò ÒØ ØÖ Ò Ñ ÓÒ Ò Û Ò Ö Ø Ö Ø Ú ÓÙÖ Û ¹ Ñ Ø Ð Ð ÒØ ÖÔÖ Ø Ø ÓÒº Ì ÔÓ Ð ØÝØÓ ÔÔÐÝØ ØÓ Ø ØÖ ØÑ ÒØ Ó ÐÔ Ò ÔÖÓØÓÒ Ý Ó Ó Ð Ö ÒØ ÑÓÒÓÔÓÐ Ö ÓÒ Ò ¾ Ò ÓØ Ö Ú Ö Ø Ò Ø Ø Ù º Ê Ö Ò ½ Ⱥ ú È Ô Ö ØÓÙ º Ã Ø ÓÖ Îº ÓÒ Ø ÒØÓÙ º ú ÓÒÓ º Å ÚÖÓÑÑ Ø Èº Ë Ñ Ð Ö ØÓ Ù Ñ ØØ ÓÖ ÔÙ Ð Ø ÓÒ Ò Ö Ö Ò Ø Ö Òº ¾ Ë ÓÖ Üº ú ̺ ÃÒÓ Ò º º Ï Ò Ö Ò Ð ØÖ Ò Å Ò Ø ÒØ Ê ÓÒ Ò Ò ÆÙÐ º º ˺ ËÔ Ø ÏÓÖÐ Ë ÒØ ½ ½µ Ôº ¾ ź ÃÓ Ð Ø Ð È Ý º Ê Úº ½ µ ½ º ½

22 Ó ¹ Ò Ø Ò ÓÒ Ò Ø ÓÒ Ó ÓÖÖ Ð Ø ØÓÑ Ò ØÖ Ô º º ÅÓÙ Ø Ò Ëº º Å Ò Ô ÖØÑ ÒØ Ó Ì ÓÖ Ø Ð È Ý Ö ØÓØÐ ÍÒ Ú Ö ØÝ Ó Ì ÐÓÒ Ê¹ ¼¼ Ì ÐÓÒ Ö Ì Ó ¹ Ò Ø Ò ÓÒ Ò Ø ÓÒ Ó ÓÖÖ Ð Ø ØÓÑ Ò ØÖ Ô ØÙ Ý Ü Ñ Ò Ò Ø «Ø Ó ÒØ Ö¹Ô ÖØ Ð ÓÖÖ Ð Ø ÓÒ ØÓ ÓÒ ¹ Ó Ý ÔÖÓÔ ÖØ Ó ØÓÑ Ý Ø Ñ Ø Þ ÖÓ Ø ÑÔ Ö ØÙÖ Ù Ò ÑÔÐ ÓÖÑÙÐ ÓÖ Ø ÓÖ¹ Ö Ð Ø ØÛÓ Ó Ý Ò ØÝ ØÖ ÙØ ÓÒº Ò ÐÝØ Ð ÜÔÖ ÓÒ ÓÖ Ø Ò ØÝ ØÖ ÙØ ÓÒ Ò ÖÑ Ö Ù Ó Ø ØÓÑ Ý Ø Ñ Ö Ö Ú Ù Ò ÓÙÖ ¹ Ö ÒØ ÜÔÖ ÓÒ Ó Â ØÖÓÛ ØÝÔ ÓÖÖ Ð Ø ÓÒ ÙÒØ ÓÒº ÁÒ ÓÒ Ò ¹ Ø ÓÒ Ø ÓÒ ¹ Ó Ý Ò ØÝ Ñ ØÖ Ü ÑÓÑ ÒØÙÑ ØÖ ÙØ ÓÒ Ò Ò Ø Ò Ö Ý Ö ÐÙÐ Ø Ò ÐÝØ ÐÐÝ Û Ð Ø Ò ØÙÖ Ð ÓÖ Ø Ð Ò Ò ØÙÖ Ð ÓÙÔ Ø ÓÒ ÒÙÑ Ö Ö Ð Ó ÔÖ Ø Ò Ø º Ë ÑÔÐ ÔÔÖÓÜ Ñ Ø ÜÔÖ ÓÒ ÓÖ Ø Ñ Ò ÕÙ Ö Ö Ù Ò Ò Ø Ò Ö Ý Ö Ð Ó Ú Òº ½

23 ËÖ Ò Ò «Ø ÓÒ Ö ÓÒ ÒØ Ø ÖÑÓÒÙÐ Ö Ö Ø ÓÒ Ö Ø Ìº Ä ÓÐ Ó ½ ú Ä Ò Ò ½ ÏºÏ Ö ¾ ½ ÁÒ Ø ØÙØ ÓÖ Ý Ó ØÖÓÒÓÑ Ö Ù ÍÒ Ú Ö Ø Ø Ã ¼¼¼ Ö Ù ÒÑ Ö ¾ Ô ÖØÑ ÒØ Ó È Ý ÍÒ Ú Ö Ø ØÝ Ó ÆÓØÖ Ñ ÁÆ ÍË ØÖ Ø Ì Ö Ø ÓÒ Ö Ø Ó Ú Ö Ð ØÖÓÔ Ý ÐÐÝ ÑÔÓÖØ ÒØÒÙÐ Ö Ö Ø ÓÒ ÓÑ Ò Ø Ý Ø ÓÒØÖ ÙØ ÓÒ Ó Ò ÖÖÓÛ Ö ÓÒ Ò Ø Ø ØÖÓÔ Ý ÐÐÝ ÑÓ Ø «Ø Ú Ò Ö º ÁÒ Ø Ø ÐÐ Ö ÔÐ Ñ Ø Ô ÖØ Ð Û Ø Ó Ø Ö ÓÒ Ò Ò Ø ÒØÖ Ò ÒÒ Ð ÑÓ Ù ØÓ Ö Ò Ò ÓÖÖ Ø ÓÒ º Ì «Ø Ó Ö ÒÓÖ Ò Ø ÐÐ Ö Ö Ø ÓÒ Ò ØÛÓÖ ÐÙÐ Ø ÓÒ Ö Ù Ø ÓÒÚ ÒØ ÓÒ Ð Ë ÐÔ Ø Ö Ö Ò Ò Ò Ò Ñ ÒØ Ó Ø Ö Ø ÓÒ Ö Ø º Ï Ö Ú Ò ÐÝØ Ð Ö Ò Ò ÓÖÖ Ø ÓÒ ØÓÖ ÓÖ Ø ÓÒØÖ ÙØ ÓÒ Ó Ò ÖÖÓÛ Ö ÓÒ Ò ØÓ Ø Ø ÐÐ Ö Ö Ø ÓÒ Ö Ø Ò Ù Ø «Ø ÓÖ ½ «µ ½ Ç ½ Ç «µ ½ Æ Ò ÓØ Ö Ö Ø ÓÒ Ó Ö Ð Ú Ò ØÓ ÜÔÐÓ Ú Ý ÖÓ Ò ÙÖÒ Ò º ½

24 Potential of Antiprotons for Imaging and Radiotherapy N. Giokaris and Th. Kalogeropoulos The University of Athens Abstract The potential of antiprotons for nuclear imaging, chemical element identification and radiotherapy is examined. A comprehensive R&D program for the characterization of these techniques is outlined.

25 Ανάπτυξη τοµογραφικής γ-κάµερα υψηλής διακριτικής ικανότητας Γ.Λούντος 1, Κ.Νικήτα 1, Ν. Ουζούνογλου 1, Ν. Γιοκαρης 2, Κ. Παπανικόλας 2, Ε. Στυλιαρης 2, Α. Βαρβαρήγου 3, Σ. Αρχιµανδρίτης 3,. Μαϊντάς 4, Κ. Στεφανής 5 1 Τµήµα Ηλεκτρολόγων Μηχανικών και Μηχανικών Υπολογιστών, ΕΜΠ 2 Τµήµα Φυσικής, Καποδιστριακό Πανεπιστήµιο Αθηνών & Ινστιτούτο Επιταχυντικών Συστηµάτων και Εφαρµογών 3 Τµήµα Ραδιοβιολογίας ΕΚΕΦΕ ηµόκριτος 4 Ινστιτούτο Ισοτοπικών Μελετών Ιατρικό Κέντρο Αθηνών 5 Ερευνητικό Πανεπιστηµιακό Ινστιτούτο Ψυχικής Υγιεινής gloudos@central.ntua.gr 1. Σκοπός Τα συστήµατα τοµοσπινθηρογραφίας (SPECT) που χρησιµοποιούνται σήµερα βασίζονται στην αρχή λειτουργίας της κάµερας Anger και µπορούν να δώσουν δισδιάστατες ή τρισδιάστατες εικόνες, διακριτικής ικανότητας 4-8mm. Στα πλαίσια αυτής της εργασίας περιγράφεται η ανάπτυξη ενός συστήµατος τοµοσπινθηρογραφίας, που βασίζεται στη χρήση ενός χωρικά ευαίσθητου φωτοπολλαπλασιαστή, µε το οποίο επιτυγχάνεται χωρική διακριτική ικανότητα 2-3mm. 2. Υλικά/Μέθοδοι Η ανιχνευτική διάταξη αποτελείται από την γ-κάµερα, η οποία περιλαµβάνει: (α) έναν κατευθυντήρα παραλλήλων οπών διαµέτρου 1.1mm, (β) έναν κρύσταλλο CsI διαµέτρου 4.6cm, ο οποίος είναι διακριτοποιηµένος σε τετραγωνικές κυψελίδες, (γ) ένα χωρικά ευαίσθητο φωτοπολλαπλασιαστή (Hamamatsu- R2486) και (δ) κυκλώµατα προενίσχυσης των σηµάτων του φωτοπολλαπλασιαστή. Τα αναλογικά σήµατα ψηφιοποιούνται σε προγραµµατιζόµενες ηλεκτρονικές µονάδες (CAMAC) και οδηγούνται σε ηλεκτρονικό υπολογιστή για επεξεργασία και ανακατασκευή δισδιάστατων εικόνων. Μία περιστρεφόµενη βάση ελεγχόµενη από τον Η/Υ επιτρέπει την περιστροφή του προς απεικόνιση αντικειµένου και τη λήψη προβολών υπό διάφορες γωνίες. Με χρήση υλοποιηµένων αλγορίθµων λαµβάνονται τοµογραφικές εικόνες και πραγµατοποιείται τρισδιάστατη ανακατασκευή του αντικειµένου. 3. Αποτελέσµατα Απεικόνιση οµοιωµάτων και τριχοειδών έδειξε ότι το σύστηµα προσφέρει διακριτική ικανότητα <2mm σε σπινθηρογραφική και <3mm σε τοµογραφική λειτουργία. Συγκρητική απεικόνιση µε κλινικά χρησιµοποιούµενα συστήµατα έδειξαν την υπεροχή της παρούσιαζόµενης διάταξης, στην απεικόνιση οργάνων µικρών ζώων και εµφυτευµένων όγκων. Η τρισδιάστατη απεικόνιση έδωσε επιπλέον πληροφορίες σε σχέση µε το σπινθηρογράφηµα. Τέλος πραγµατοποιήθηκαν δυναµικές µελέτες. 4. Συµπεράσµατα Το αναπτυσσόµενο σύστηµα τοµοσπινθηρογραφίας µπορεί να χρησιµοποιηθεί για την πραγµατοποίηση ραδιοβιολογικών µελετών σε µικρά ζώα και για την απεικόνιση µικρών ανθρωπίνων οργάνων. Ιδιαίτερη εφαρµογή αναµένεται στη µαστογραφία, όπου τόσο το µικρό µέγεθος του ανιχνευτή όσο και οι επιδόσεις του προσφέρουν πολλά πλεονεκτήµατα συγκρητικά µε τα εµπορικά διαθέσιµα συστήµατα.

26 Μελέτη ιακριτικής Ικανότητας γ κάµερας SPECT Β. Σπανουδάκη 1, 2, Ν. Γιόκαρης 1, 2, Γ. Λούντος 3, Κ. Ν. Παπανικόλας 1, 2, Ε. Στυλιάρης 1, 2. 1 Τµήµα Φυσικής, Τοµέας Πυρηνικής Φυσικής και Στοιχειωδών Σωµατιδίων, Καποδιστριακό Πανεπιστήµιο Αθηνών 2 Ινστιτούτο Επιταχυντικών Συστηµάτων και Εφαρµογών 3 Τµήµα Ηλεκτρολόγων Μηχανικών και Μηχανικών Υπολογιστών, ΕΜΠ virginia@rtm.iasa.uoa.gr Στο πλαίσιο της χρησιµοποίησης συστηµάτων τοµοσπινθηρογραφίας για την απεικόνιση ανθρώπινων οργάνων, γίνεται αξιοποίηση της λειτουργίας της γ κάµερας του Ι.Ε.Σ.Ε. Σκοπός αυτής της εργασίας είναι η αξιολόγηση της λειτουργίας της γ κάµερας µέσω της µελέτης της ενεργειακής διακριτικής ικανότητάς της. Χρησιµοποιήθηκαν τα πρωτογενή δεδοµένα που συλλέχθηκαν από τη γ κάµερα µε πηγή Tc 99 υπό την µορφή αναλογικών σηµάτων που αποδίδουν οι 8*8 άνοδοι ενός ευαίσθητου ως προς τη θέση φωτοπολλαπλασιαστή (Position Sensitive Photomultiplier). Επιλέγοντας περιοχές µικρού εύρους γύρω από κάθε ανοδικό σήµα αποδίδονται τα αντίστοιχα ενεργειακά φάσµατα και υπολογίζονται διορθωτικοί παράγοντες ενδεικτικοί της µετατόπισης της φωτοκορυφής σε κάθε φάσµα.

27 X-Ray Fluorescence Analysis of a Gold Ibex and other Artifacts from Akrotiri A. G. Karydas a, T. Pantazis b, C. Doumas c, A. Vlachopoulos c, P. Nomikos d, E. Thomson e, C. Vecoli e, M. Dinsmore e, Ch. Zarkadas a a Laboratory for Material Analysis, Institute of Nuclear Physics, NCSR Demokritos, Aghia Paraskevi, Athens, Greece. b Amptek Inc., 6 De Angelo Drive, Bedford, MA USA c Akrotiri Excavations, Santorini, Greece. d The Thera Foundation, Middlesex Street, London E1 7HY, UK. e Photoelectron Corp. 5 Forbes Road, Suite 2, Lexington, MA USA. Abstract In-situ X-ray fluorescence analysis (XRF) of ancient artifacts from the excavation area was performed using a novel X-ray instrumentation, composed of a portable silicon PIN thermoelectrically cooled X-ray detector, a miniature X-ray source, and portable data acquisition devices. The main objective of the analyses in Akrotiri was to explore the potential of the technique to provide answers to a wide range of archaeometric questions regarding the bulk composition of metal alloys, especially of gold, the characterization of corrosion products in bronze artifacts, identification of inorganic elements which are fingerprints of the minerals used in wall-painting pigments, and of the painting materials and techniques used for the decoration of clay vase surfaces. Among the analysed artifacts are a unique gold ibex, a bronze dagger and blade, various pigments from the wall paintings of room 3 in Xeste 3, decoration pigments from rosettes of faience, a bichrome jug, and other clay vases. The results of the in-situ XRF survey, primarily those of the bulk composition and soldering technology of the gold ibex, are discussed and compared with literature. 1

28 Development of X-ray fluorescence methods by use of a Mo X-ray tube and their application in the case of biological samples Ch. Zarkadas, A.G. Karydas and T. Paradellis Laboratory for Material Analysis, Institute of Nuclear Physics, NCSR Demokritos, Aghia Paraskevi, Athens, Greece. Abstract In the present work two different experimental arrangements, aiming in the X-ray fluorescence analysis of solid and liquid biological samples respectively, were developed and studied both theoretically and experimentally in combination with a Mo anode X-ray tube: The secondary target XRF (STXRF) and the Total Reflection XRF set-up (TXRF). The secondary target XRF irradiation chamber was designed and constructed in our laboratory. Careful choice of the materials combined with the tight geometry used, minimize the presence of interference peaks in the spectrum and offer high intensity of the exciting beam at the sample position. Optimum performance was ensured by means of an extended theoretical and experimental study of various parameters affecting the analytical capabilities of secondary target XRF systems, such as: The choice of secondary target material and the operational conditions of the X-ray tube. The secondary target XRF set-up was applied in the determination of the concentrations of trace elements in a pool blood serum sample. A simple preparation technique, like the freeze-drying process was employed, resulting in detection limits of 15 ng/ml for most metal trace elements and for a 6000 sec measuring time. The accuracy of the whole experimental procedure, examined by internal standardization and by analyzing the reference standard material A-13, was found to be about 4% over the whole atomic number range. For the determination of the mass absorption coefficients, necessary in the quantification step, a modified version of the emission transmission method was employed. Total Reflection X-Ray Fluorescence (TXRF) is a well-established method, mainly applied in the analysis of liquid samples, offering very low detection limits in most of the cases. Direct application of the TXRF method is not so efficient in blood serum analysis, since the high content of the organic matrix increases significantly the background due to Compton scattering. Chemical treatment of the blood serum samples and related preconcentration techniques have been suggested in literature, but they are time consuming and increase the possibility of adding contaminants in the sample. In this work, the applicability of direct TXRF analysis in blood serum samples was examined. The insertion of a Mo filter after the cut-off reflector has been found to improve significantly the peak to background ratio, especially for the elements of interest such as Cu, Zn, Se and Br. The influence of self-absorption phenomena in the quantification procedure was also investigated with respect to the internal standard used and the sample mass analyzed. Precision and accuracy in the analysis was found to be about 4% over the whole atomic number range. Detection limits were in the order of 25ng/ml for most metal trace elements and a measuring time of 3600 sec.

29 Analysis of Ancient Glass Using Ion Beams and Related Techniques. S. Kossionides 1, M. Kokkoris 1, A. G. Karydas 1 and T. Paradellis 1 G. Kordas 2, G. Moraitou 2a 1 Material Analysis Laboratory, Institute of Nuclear Physics, NCSR Demokritos 2 Sol-Gel Laboratory, Institute of Materials, NCSR Demokritos a Ministry of Culture Abstract Ion Beam Analysis (IBA) techniques are established as an indispensable tool for material analysis. They are very powerful when applied to the examination of uniform layers. In recent years they have been also used for the quality control of implanted layers, which improve the mechanical or chemical properties of common materials. The use of IBA techniques for the study of corrosion is impeded by the non-uniformity of such layers, which renders the analysis difficult. In the Material Analysis Laboratory of the Institute of Nuclear Physics, a combination of experimental techniques and analytical algorithms has been developed, which allows the non-destructive examination of corrosion layers on cultural artifacts. Ancient glass fragments from Kenchreai, Greece, were analyzed with ion beam techniques, in order to examine the applicability of the latter to the characterization of the surface. The relative distribution of heavy components was determined by X-Ray Fluorescence (XRF). Nuclear reactions were used to determine the depth distribution of H, O, C and Si. The Hydrogen distribution rises sharply from the surface, reaching a maximum of at/cm 3 at 0.5 µm and then decays smoothly to a depth of approximately 2 µm. Examination of the same samples with α- particles, indicates a depletion of Silicon in the same surface region, while the Oxygen distribution is uniform. A detailed analysis, using the 28 Si(p, p) reaction, which resonates at MeV, confirms the depletion and other non-uniformities in the Silicon distribution.

30 ÁÆ ÇÊÅ ÌÁÇÆ ÇÆ ÌÀ ËÁ Æ ÇÌÀ Ê ÉÍ ÆÌÁÌÁ Ë Ç ¹ÇÊ ÁÌ ÄË ÁÆ À È ÊÆÍ Ä Á ÊÇÅ È ÊÁÅ ÆÌ Ä ¹ Æ Ê Á Ë Åº º ÖÝÔ Ó º º ÃÓÙØÖÓÙÐÓ Ò Ì º º È ØÖ ÓÙ Ô ÖØÑ ÒØ Ó Ì ÓÖ Ø Ð È Ý Ö ØÓØÐ ÍÒ Ú Ö ØÝ Ó Ì ÐÓÒ Ö ØÖ Ø Ò ÔÔÖÓ ÔÖÓÔÓ ÓÒ Ø Ó Û Ø ÜÔ Ö ¹ Ñ ÒØ ÐÐÝ ÒÓÛÒ ØÛÓ ÐÓÛ Ö Ò Ö Ý ÒÚ ÐÙ Ó ¹ Ô ÖØ Ð ÙÑ ØÓ ÓÙÒ Ò ÝÔ ÖÒÙÐ Ù Ý ÒØÖ Ð ÔÓØ ÒØ Ð ÖÓÑ ÖÐÝ Û Ð Ó Ø Ñµ Ö Ð ØÓ ÔÖÓÚ Ò ÖØ Ò Ö Ø Ö Ö Ø Ò ÓÖÑ Ø ÓÒ ÓÒ Ø Ñ Ø Ó ÓØ Ö Ù ÙÐ ÕÙ ÒØ Ø Ù Ø ÖºÑº º Ö Ó Ø ÓÖ¹ Ø Ð Ò Ø Ò Ö Øº ÁÒ Ø ÓÒ ØÛÓ Ò ÕÙ Ð Ø Ö Ð Ø Ò Ø ÖÓÙÒ ¹ Ø Ø Ñ Ò ÕÙ Ö Ö Ù Ó Ø ÓÖ Ø Ó Ô ÖØ Ð Ò ÒØÖ Ð ÔÓ¹ Ø ÒØ Ð Ò Ø Ò Ø Ò Ö Ý Ö Ô Ø Ú ÐÝ ØÓ Ø Ô Ò Ó Ø ØÛÓ ÐÓÛ Ø Ò Ö Ý Ð Ú Ð Ö ÒÚ Ø Ø Ò ÙÖØ Ö Ù Ò ÓÒÒ Ø ÓÒ Û Ø Ø ¹ ÝÔ ÖÒÙÐ º ½

31 ÑÔÐ Ö ÔÓÒ ÙÒØ ÓÒ ÓÖÑ Ð Ñ ÓÖ Ñ Ùѹ ÚÝ ÝÔ ÖÒÙÐ Ì Ó ÓÖ È ØÖ ÓÙ Ô ÖØÑ ÒØ Ó Ì ÓÖ Ø Ð È Ý ÍÒ Ú Ö ØÝ Ó Ì ÐÓÒ ¼¼ Ì ÐÓÒ Ö Ì Ö Ú Ö ØÝ Ó Ô ØÖ ÓÖ ÝÔ ÖÒÙÐ ÖÓÑ Ð Ø ØÓ ÚÝµÛ ÓÒØ Ò Ñ ÒÝ Ô Ö Ò Ò ÖÓÑ Ø Ô Ø ÓÖ Ø ØÓ Ø ÙÖ ÓÒ º Ò ÔÔÖÓ ÔÖ ÒØ ÓÖ Ø ÐÙÐ Ø ÓÒ Ó Ø ÓÙÒ Ø Ø Ô ÖÙÑ Ó ÝÔ ÖÒÙÐ Û Ö Ø ÖÓ Ø ÓÒ ÜÔÖ Ø ÖÓÙ Ø Ö ÔÓÒ ÙÒØ ÓÒº Ì Û Ú Ò Ø Ö Ñ ÛÓÖ Ó Ø Ö Ò ÙÒØ ÓÒ Ñ Ø Ó Û Ø ÕÙ Ö Û ÐÐ ÓÔØ Ð ÔÓØ ÒØ Ð Ù Ò Ø ÔÐ Ò Û Ú º Ò Ò ÐÝØ ØÖ ØÑ ÒØ Û Ñ ÓÖ Ø ÔÖÓÑ Ò ÒØ Ô Û Ø Ø ÓÒØÖ ÙØ ÓÒ Ó ÓÒÐÝ Ø Ú Ð Ò Ò ÙØÖÓÒ¹ ÓÐ Ö Ò Ù Ò ÓÐ Ò Û Ó Ø Ò ÓÖ Ø Ö Ø Ô ØÖÙѺ Ì Ñ Ø Ó Û ÔÔÐ Ñ ÒÐÝ ØÓ Ø Ã µ Ñ ÙÑ ØÓ ÚÝ ÝÔ ÖÒÙÐ Ò Ð Ó ØÓ Ø Ã Ò¹ Ø µ ÝÔ ÖÒÙÐ Ö Ô ØÖ Û Ø Ö Ô Ø ØÓ Ø Ö «Ö Ò µº Ì Ö ÙÐØ Ö Ø ØÓÖÝ ÓÑÔ Ö ØÓ Ø ÜÔ Ö Ñ ÒØ Ð Ú ÐÙ º Ì Ñ Ò Ú ÒØ Ó Ø ÔÖÓÔÓ ÑÓ Ð Ø ÑÔÐ Øݺ ÈÓ Ð ÜØ Ò ÓÒ Ò ÑÔÖÓÚ Ñ ÒØ Ó Ø Ñ Ø Ó Ö Ð Ó Ù Ø º ½

32 Deformed Hartree-Fock calculations for semileptonic processes in nuclei T.S. KOSMAS Theoretical Physics Division, University of Ioannina, GR Ioannina, Greece In nuclear structure calculations, the Deformed Hartree-Fock (DHF) provides generally a good description for the low-lying spectroscopic properties of odd-even, odd-odd and even-even nuclear systems of which the consideration of the deformation is motivated by many reasons. The common random phase approximations (RPA, QRPA, etc.) mostly used to accurately evaluate the transition matrix elements in many nuclear processes [1,2], are appropriate for only spherical even-even nuclear systems even though, sometimes, isotopes considered as rather deformed are studied. In the present work, we discuss the treatment within the DHF method of nuclei in the region A = This region includes isotopes (like 72 Ge, 76 Ge, 72 Se, etc) interesting for studying many nuclear processes as the ββ-decay, scattering of dark matter candidates off nuclei, µ e ± conversions in nuclei. In our calculations the model space comprises 1p 3/2, 0f 5/2, 1p 1/2 and 0g 9/2 single particle orbitals assuming 56 Ni to be the inert core. The effective interaction employed, has been quite successfully used previously to describe many important features of the nuclei in this region. The lowest prolate Hartree-Fock single particle spectrum of some isotopes ( 72 Ge, 76 Ge) has been used to test the good angular momentum states which in this method are projected out from the intrinsic HF states. As an application, we examine the predictions of DHF for the exotic (µ, e ) conversion process. The contributions of all basic µ e operators originating from a general effective Lagrangian [2] are compared with those of normal QRPA methods obtained previously [1]. [1] T.S. Kosmas, Nucl.Phys. A 683(2001)443; Prog.Part.Nucl.Phys. 48(2002)342; NIM Phys.Res. A, in press. [2] T.S. Kosmas, S. Kovalenko and I. Schmidt, Phys. Lett. B 511(2001)203; 519(2001)78. 1

33 ÆÙÐ Ö Ñ ØÖ Ü Ð Ñ ÒØ ÓÖ ÜÐÙ Ú ØÖ Ò Ø ÓÒ Ó Ñ ¹Ð ÔØÓÒ ÔÖÓ Îº º À ËÁÇÌÁ Æ ÌºËº ÃÇËÅ Ë Ì ÓÖ Ø Ð È Ý Ú ÓÒ ÍÒ Ú Ö ØÝ Ó ÁÓ ÒÒ Ò Ê¹ ½½¼ ÁÓ ÒÒ Ò Ö ØÖ Ø Ì ÓÖÑ Ð Ö ÔØ ÓÒ Ó Ø ØÖ Ò Ø ÓÒ Ñ ØÖ Ü Ð Ñ ÒØ ÓÖ Ñ ¹Ð ÔØÓÒ ÔÖÓ Ò ÒÙÐ ÑÔÖÓÚ º Ý ÙØ Ð Þ Ò Ø ÑÙÐØ ÔÓÐ ÓÑÔÓ Ø ÓÒ Ó Ø ÖÓÒ ÙÖÖ ÒØ ÔÖÓ ÙÖ Û ÔÔÖÓÔÖ Ø Ò Ø Û Ò Ø Ò Ø Ð Ò Ò Ð ÒÙÐ Ö Ø Ø Ú Û Ðй Ò Ô Ò Ó Ô Ò Ò Ô Ö ØÝ Ø ÓÔ Ö ØÓÖ Ö ÔÓÒ Ð ÓÖ ÒÝ Ñ ¹Ð ÔØÓÒ ÔÖÓ Ò ÛÖ ØØ Ò Ò Ø ÖÑ Ó Ú Ò Ò Ð ¹ Ó Ý Ø Ò ÓÖ ÓÔ Ö ØÓÖ º ÁØ ÒÓÛÒ Ø Ø Ø Ñ ÒÝ¹Ô ÖØ Ð ÒÙÐ Ö Ñ ØÖ Ü Ð Ñ ÒØ Û Ø ÖÑ Ò Ø ÖÓ Ø ÓÒ Ó Ø ÓÒ Ö Ö Ø ÓÒ Ö Ö Ý ÓÒ ¹ Ó Ý Ñ ØÖ Ü Ð Ñ ÒØ Ò ÓÒ ¹ Ó Ý ØÖ Ò Ø ÓÒ Ò Ø Û Ö Ø Ð ØØ Ö ÕÙ ÒØ Ø Ö Ó Ø Ò Û Ø Ò ÓÑ ÒÙÐ Ö ÑÓ Ðº ÁÒ Ø ÔÖ ÒØ ÛÓÖ ÑÔÐ ÐÓ ÜÔÖ ÓÒ ÓÖ Ø Ò Ð ¹Ô ÖØ Ð Ö Ù Ñ ØÖ Ü Ð ¹ Ñ ÒØ Ó Ø ÑÙÐØ ÔÓÐ Ø Ò ÓÖ ÓÔ Ö ØÓÖ Ö ÓÒ ØÖÙØ Ý Ù Ò ÖÑÓÒ Ó ÐÐ ØÓÖ º Ì ÜÔÖ ÓÒ ÔÖÓ ÙØ Ó ÔÓÐÝÒÓÑ Ð Û Ø ÓÒ Ø ÒØ Ó Æ ÒØ Ù Ù ÐÐÝ Ñ¹ ÔÐ ÒÙÑ Ö Ø Ñ Ò ÜÔÓÒ ÒØ Ðµ Ö ÙÒØ ÓÒ Ó Ø ÑÓÑ ÒØÙÑ ØÖ Ò Ö ØÓ Ø ÒÙÐ Ù º Ì ÓÒ Ø ÒØ Ó Æ ÒØ Ó Ø ÔÓÐÝÒÓÑ Ð Ö ÐÙÐ Ø Ù Ò ÔÔÖÓÔÖ Ø Ó µ ÓÖ Ò Ð ¹Ô ÖØ Ð ÒÙÐ Ö Ñ ØÖ Ü Ð Ñ ÒØ Û ÓÚ Ö Ø Û ÓÐ Ô Ö Ó Ý Ø Ñº Ï Ø Ø Ó Ø ÓÖÑ Ð Ñ ÔÖ Ú ÓÙ ÙÒ Ñ Ø Ó Ù ÓÖ Ø ÐÙÐ Ø ÓÒ Ó Ø ØÖ Ò Ø ÓÒ Ñ ØÖ Ü Ð Ñ ÒØ ÒÚÓÐÚ Ò Ø ÖÓ Ø ÓÒ Ó ÐÐ Ñ ¹Ð ÔØÓÒ Ö Ø ÓÒ Ö ÑÔÖÓÚ º Ð Ó Ô Ø ÓÖÑÙÐ Û Ú Ø ÒÙÐ Ö ÑÓÑ ÒØ Ó ÒÝ ÓÖ Ö º º Ò Ò ÙØÖ ÒÓÐ ÓÙ Ð Ø Ý Ò ÙØÖ ÒÓ¹ÒÙÐ Ù Ö Ø ÓÒ Øºµ Ö ÑÔÐ º

34 ËÝ Ø Ñ Ø ØÙ Ý Ó Ø ÑÙÓÒ¹ÒÙÐ Ù ÓÚ ÖÐ Ô ÒØ Ö Ð ÓÖ Ú Ö ÓÙ ÔÖÓ Ò ÑÙÓÒ ØÓÑ Æ È Ò ÓØ Ò ÌºËº ÃÓ Ñ Ô ÖØÑ ÒØ Ó È Ý ÍÒ Ú Ö ØÝ Ó ÁÓ ÒÒ Ò Ê¹ ½½¼ ÁÓ ÒÒ Ò Ö ØÖ Ø Ø ÒÓÛÒ Ø ÓÙÒ ÑÙÓÒ Ó ÑÙÓÒ ØÓÑ Ò Ô ÖØ Ô Ø Ò Ñ ÒÝ Ð ØÖÓ¹ Û ÔÖÓ Ø ÐÐÓÛ ÒÒ Ð Ó Ø ÓÖ Ò ÖÝ ¹ ÔØÙÖ Ý Ø ØÓÑ ÒÙÐ Ù µ ½µ Ò Ø ÑÙÓÒ Ý Ò ÓÖ Ø Û ÐÐ Ø ÜÓØ ÒÒ Ð Ó Ø ÑÙÓÒ¹ØÓ¹ Ð ØÖÓÒ µ µ Ò ÑÙÓÒ¹ØÓ¹ÔÓ ØÖÓÒ µ ¾µ ÓÒÚ Ö ÓÒ º Ì Ð ØØ Ö Ö Ø ÓÒ Ú ÒÓØ Ò Ò Ý ÜÔ Ö Ñ ÒØ ÙÔ ØÓ ÒÓÛ ÙØ Ø Ý Ö ÔÖ Ø Ý Ú Ö ÓÙ ÜØ Ò ÓÒ Ó Ø Ø Ò Ö ÑÓ Ð Ø Ý Ú ÓÐ Ø Ø ÚÓÖ Ò»ÓÖ Ð ÔØÓÒ ÕÙ ÒØÙÑ ÒÙÑ Ö µº ÓÖ ÐÐ Ø ÓÚ ÑÙÓÒ ÔÖÓ Ø ÑÙÓÒ¹ÒÙÐ Ù ÓÚ ÖÐ Ô ÒØ Ö Ð Ö Ò ÖÝ Ò ÓÖ Ö ØÓ ÐÙÐ Ø Ø Ö Ð Ú ÒØ Ö Ø º Ì ÒØ Ö Ð Ò Ú ÐÙ Ø Ò Ø ÓÒ ØÓ Ø ÒÙÐ Ö Ø Ø Ø Û Ú ÙÒØ ÓÒ Ó Ø ÓÙÒ ÑÙÓÒ Ð Ó Ø Ø Ó Ø ÓÙØ Ó Ò ¹ Ð ÔØÓÒµ Ö ÒÓÛÒº ÁÒ Ø ÔÖ ÒØ ÛÓÖ Û Ô Ö ÓÖÑ ÔÖ ÐÙÐ Ø ÓÒ Ó Ø ÑÙÓÒ Ò Ð ØÖÓÒ»ÔÓ ØÖÓÒµ Û Ú ÙÒØ ÓÒ ÓÖ ÓØ Ø Ë ÖĐÓ Ò Ö Ò Ö ÕÙ Ø ÓÒ º Ï Ù ÑÓ ÖÒ Ò ÙÖ Ð Ò ØÛÓÖ Ø Ò ÕÙ ØÓ ÓÚ ÖÓÑ Ø ÆÙÐØ Ö Ò ÖÓÑ Ø Ò Ø Þ Ó Ø ÒÙÐ ÓÒ Ò ÒÙÐ Ö ÓÙÐÓÑ ÔÓØ ÒØ Ðº ÓÑ ÔÔÐ Ø ÓÒ Ø Ó Ø Ò ÑÙÓÒ¹ ÒÙÐ Ù ÒØ Ö Ð ÓÖ Ú Ö ÓÙ ÑÙÓÒ ØÓÑ Ö Ó Ò ØÓ Ù ÓÖ Ú ÐÙ Ø Ò ÜÐÙ Ú ÑÙÓÒ¹ ÔØÙÖ Ö Ø Ò ÑÙÓÒ ØÓ Ð ØÖÓÒ»ÔÓ ØÖÓÒ ÓÒÚ Ö ÓÒ Ö Ò Ò Ö Ø Ó º ½

35 Nuclear structure is governed by the fundamental laws of electromagnetism L. A. Kaliambos Institute of Larissa, Komninon 15, Larissa 41223, Greece Abstract Contradicting interpretations of the nuclear force as given by two contrasted approaches like the meson theory and the quantum chromodynamics, are overcome here by reviving the basic electromagnetic laws which are applicable on the existing charged subconstituents in nucleons. On this basis, considerable charge distributions in nucleons are determined after a careful analysis of the magnetic moments and the results of the deep inelastic scattering. Basic equations derived from the distributed charges of oriented spins of nucleons give strong and short ranged forces leading exactly to the binding energies of the deuteron and other nuclei. According to these interactions, p-p and n-n systems repel and only the p-n bonds form rectangles and closely packed parallelepipeds. Such contrary forces create structures of saturation and of finite number of nucleons. They also invalidate the charge independence hypothesis and differ fundamentally from the central potential and the effects of the Pauli principle of the electronic configurations responsible for the development of the models of the Fermi gas and nuclear shell. There are two kinds of p-n bonds, which imply anisotropy, leading often to elongated shapes of vibrational and rotational modes of excitation, while the surface tension contributes to the creation of non elongated shapes of stable arrangements. Finally, for A>40 a type of shell structure provides new rules for understanding the structure of magic nuclei for N>Z and the increasing ratio N/Z with A.

36 On the ph-dependent strontium adsorption by Al-PILCs, impregnated with carboxylate groups of various acid strengths C.A. Papachristodoulou, P.A. Assimakopoulos, N-H.J. Gangas Nuclear Physics Laboratory, Department of Physics, The University of Ioannina, Ioannina, Greece Abstract The impregnation of a PILC with carboxylate groups is proposed as a means to improve the adsorption properties of the material for strontium ions. The role of solution ph and carboxylate acid strength in the functionalization of the organic groups is probed by base titrations. In comparing the pristine-pilc with PILCs carrying either oxalate or acetate impregnates, enhanced strontium uptake is evidenced by the modified solids, initiated at ph 6 and 8 in the presence of oxalate and acetate, respectively. The effect on uptake is higher in the former case, amounting to an increase in strontium adsorption by a factor between two and three, depending on the ph range. To further elucidate the significance of the carboxylate acid strength in cation uptake phenomena, strontium adsorption isotherms are presented for PILCs carrying acetate, oxalate, malonate and citrate groups. The results demonstrate that, at constant ph, adsorption increases with increasing acid strength.

37 X-Ray spectrometric studies using thin silicon crystals. Advantages and applications A.G. Karydas a, Ch. Zarkadas a, A. Kyriakis a, J. Pantazis b, A. Huber b, R.Redus b C. Potiriadis c and T. Paradellis a a Laboratory for Material Analysis, Institute of Nuclear Physics, NCSR Demokritos, Aghia Paraskevi, Athens, Greece b Amptek, Inc., 6 De Angelo Drive, Bedford, Mass U.S.A. c Greek Atomic Energy Commission, Aghia Paraskevi, Athens, Greece Abstract This paper presents the peak-to-background ratio improvement, which can be achieved in PIXE and XRF applications by the use of thin crystal detectors. This improvement becomes apparent in the presence of an intense γ-ray source, which can be produced either after proton irradiation of a sample (PIXE), or after the deexcitation of the radionuclide in Radioisotope induced XRF analysis (RIXRF). In order to study theoretically the energy response of a silicon crystal in the X-ray energy region with respect to its thickness and the energy of the incident γ- radiation, a Monte-Carlo simulation was performed. Experimentally, two detectors having crystal thickness of 300 µm and 3 mm respectively were employed in specific analytical applications of PIXE, PIXE induced XRF and RIXRF techniques. The peak-to-background ratios obtained for various characteristic X-rays were compared between the two detectors. The performance of the two detectors was also compared in monochromatic XRF analysis of samples with low average atomic number matrix content. 1

38 Copper and sulphur depth profile in patina layers using NRA and RBS G. Kalliabakos 1, S.Kossionides 1, P. Misailides 2, C.T.Papadopoulos 3 and R.Vlastou 3 1) Inst. of Nuclear Physics, NCSR Demokritos, Aghia Paraskevi, Athens 2) Lab. of Radiochemistry, Aristotle University of Thessaloniki, Thessaloniki 3) Dept. of Applied Physics, National Technical University of Athens, Athens Abstract A combination of nuclear reaction analysis (NRA) and Rutherford backscattering spectroscopy (RBS) were utilized in order to obtain information on the depth distribution of sulphur and copper in artificially produced and natural patina layers. The copper profiling was performed by using the reaction 63 Cu(p,p γ) 63 Cu and detecting the 1327 kev γ-ray deexciting the third excited state to the ground state of 63 Cu produced. For the determination of sulfur the 2230 kev γ-ray was used, deexciting the first excited state to the ground state of 32 S formed through the reaction 32 S(p,p γ) 32 S, which exhibits three sharp resonances at projectile energies 3.094, and MeV. The relevant cross-sections were measured in the energy range between 3.0 and 3.7 MeV in steps of 20 kev at 125 o to the incident proton beam direction. Supporting information on the depth distribution of oxygen and the other elements of the patina samples was obtained by p-rbs (E p = 1.5 MeV; θ = 160 o ).

39 «Ø Ó Ö ÓÐÓ Ð Û ÔÓÒ Ìº ºÄ ÓÐ Ó ½ À ÐÐ Ò Å Ö ÒØ Å Ö Ò ÑÝ Ô ÖØÑ ÒØ Ó Ë Ò ÀÝ Ö Á Ð Ò ½ ¼ ¼ Ö ØÖ Ø Ò ÒÚ Ø Ø ÓÒ Ó Ö ÓÐÓ Ð Û ÔÓÒ «Ø Ô Ö ÓÖÑ Ý ÑÔÐÓÝ Ò ÓÑÔÙØ Ö ÑÙÐ Ø ÓÒ Ñ Ø Ó Ò Ú Ö ÓÙ Ñ Ø Ñ Ø Ð ÑÓ Ð º Ì ØÙ Ý ÓÚ Ö ÐÐ Ñ ÓÖ Í ÑÑÙÒ Ø ÓÒ Ø Ø Ö Ù Ò ÑÓ ÖÒ Û Ö Ö Ò ÐÙÐ Ø Ø ÜÔ Ø Ò Ö ÑÓÖØ Ð ØÝ ÙÒØ ÓÒ Ó Û ÔÓÒ Ò ØØÐ ÓÒ Ø ÓÒ º ÅÓÖ ÓÚ Ö Ú Ö ÓÙ ÓÖÑ Ó ÖÙ Ö ÓÐÓ Ð Ú Ø Û ÔÓÒ Ó Ó Ò Ò ÙÒÓÒÚ ÒØ ÓÒ Ð Ø ÖÖÓÖ Ø ØØ µ Ö Ð Ó ØÙ Ò ÓÖ Ö ØÓ Ú ÐÙ Ø Ø Ö ÙÐØ Ó Ù Ò ØØ ÙÖ Ò Ø Ø Ò ¾¼¼ ÓÐÝÑÔ Ñ º ½ Ñ Ð Ø ÓÐ ÓÐÔ Ý º ÙØ º Ö ½

40

41 ŒŒˆŽŠ ˆ Š Š ˆŽŠ ˆ Š ˆ { ² Š ±½³ ¹². ü ü - ª ª¼ µ ½«± ² ± ««² ¼ª± ²ª ±¼ ± ² ª ¾ ³«œ «µ Š¹ Ÿ ¹ ±¼ ± ² ± ¹ ž± ² ƒ ± ³¼ µ«² ¼ª± ²ª ± ² ª œ± ² ³ œ² Š¹ Ÿ ¹ Ÿ ² ª ±ž µ± œ ½ µ ¾ «²