Study of transfer reaction properties with stable and unstable heavy ion beams

doctoral thesis

• Title (croatian): Istraživavanje svojstava reakcija prijenosa nukleona upotrebom stabilnih i nestabilnih ionskih snopova
• Author: Petra Čolović
• Mentor: Suzana Szilner (mentor)
• Committee member: Matko Milin (predsjednik povjerenstva)
• Committee member: Suzana Szilner (član povjerenstva)
• Committee member: Nils Paar (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2020-10-27, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics
• Universal decimal classification (UDC): 53 - Physics

Abstract

The main subject of this thesis is to show that transfer reactions with the neutron-rich unstable beams and the heavy targets could be very adequate for the production of the neutron-rich heavy nuclei. To that purpose, the measurement of 94^Rb+208^Pb transfer reaction has been performed at the energy of about 30% above the Coulomb barrier, provided by the radioactive ion beam facility of CERN (HIE-ISOLDE). The high-resolution and high-efficiency experimental set-up consisted of a large γ-array MINIBALL, coupled to the CD fragment detector of wide angular range. From the measured particle-γ and particle-γ-γ coincidences, the characteristic γ transitions were attributed to 207^Pb, 208^Pb, 209^Pb and 210^Pb, and their binary partners, the isotopes of Rb. Based on the attributed γ transitions, the total cross sections in Pb isotopes were successfully constructed. In particular, in channels populated by transfer of neutrons from 94^Rb beam to 208^Pb target, the cross section of 138(8) mb was evaluated in 209^Pb, and 41(7) mb in 210^Pb. These significant values quantify the production of the moderately neutron-rich heavy nuclei for the first time in the transfer reaction induced by an unstable beam. The obtained results were fairly reproduced with the semi-classical model GRAZING, thus encouraging the use of the presented approach for the population of the neutron-rich heavy nuclei. This thesis strongly suggests that the presently available experimental techniques and radioactive ion beam intensities are very suitable to extend the reaction mechanism and the nuclear structure studies farther from the valley of stability.

Abstract (croatian)

Primarni zadatak ove disertacije je pokazati da su reakcije prijenosa nukleona s neutronski bogatim snopovima i teškim metama vrlo pogodne za proizvodnju neutronski bogatih teških jezgara. S tim ciljem, izvršeno je mjerenje reakcije 94^Rb+208^Pb s energijom snopa otprilike 30% iznad kulonske barijere, dobivenom pri postrojenju za radioaktivne snopove u CERN-u (HIE-ISOLDE). Eksperimentalni postav visoke rezolucije i efikasnosti sastojao se od složenog γ-spektrometra MINIBALL, vezanog s čestičnim detektorom širokog kutnog raspona, naziva CD. Mjerenje koincidencije između γ zraka i čestica omogućilo je pridjeljivanje karakterističnih γ prijelaza izotopima olova, 207^Pb, 208^Pb, 209^Pb i 210^Pb, i njihovim binarnim partnerima, izotopima rubidija. Na temelju pridijeljenih prijelaza, uspješno su konstruirani ukupni udarni presjeci u izotopima olova. Posebice, u kanalima prijenosa neutrona od snopa 94^Rb ka meti 208^Pb, udarni presjek u 209^Pb iznosio je 138(8) mb, i 41(7) mb u 210^Pb. Ove značajne vrijednosti udarnih presjeka po prvi puta opisuju proizvodnju umjereno neutronski bogatih teških jezgara u reakciji prijenosa nukleona uz upotrebu nestabilnog snopa. Dobiveni rezultati su dobro opisani računom GRAZING, te potiču daljnju upotrebu predstavljenog eksperimentalnog pristupa za proizvodnju teških jezgara bogatih neutronima. Disertacija jasno demonstrira da je korištenjem trenutno dostupnih eksperimentalnih tehnika i intenziteta radioaktivnih snopova moguće proširiti daljnja istraživanja nuklearne strukture i mehanizma reakcije značajno dalje od doline stabilnosti.

• Keywords: reactions; neutron-rich heavy nuclei; γ-spectroscopy; total cross section
• Keywords (english): reakcije prijenosa; neutronski bogate teške jezgre; spektroskopija gamazracenja; ukupni udarni presjek
• Language: english
• URN:NBN: urn:nbn:hr:217:068891
• Promotion: 2020
• Study programme: Title: Physics; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje fizika (doktor/doktorica znanosti, područje prirodnih znanosti, polje fizika)
• Type of resource: Text
• Extent: 182 str.
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-11-13 09:01:14