Structure of Nuclei with Extreme Neutron/Proton Ratios

Lead Research Organisation: University of Surrey
Department Name: Physics

Abstract

Neutron-rich nuclei to be studied will be produced in world leading facilities. The isotope-separation on-line technique will be used at CERN-ISOLDE, and projectile fission at RIKEN. In an already approved experiment at CERN-ISOLDE, the single magic radioactive nucleus 206Hg will be studied in low energy Coulomb excitation. The experiment is expected to provide information on the collectivity, both quadrupole and octupole, in this region. At RIKEN the nuclei of interest will be populated via secondary fragmentation of fission products, via beta decay and transfer reactions. The obtained level schemes will be used to refine nuclear theories and to increase their predictive power for even more exotic nuclei.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
ST/N504440/1 01/10/2015 30/09/2020
1651929 Studentship ST/N504440/1 01/10/2015 31/03/2019 Thomas Andrew Berry
 
Description The research has significantly improved our knowledge of the low-energy excited states in the 207Tl nucleus. It has revealed more information on the behaviour of the collective vibrational octupole phonon in this region of the nuclear chart by identifying states which occur as a result of the phonon. From these results, and those of previous experiments, we have attempted to answer why current state-of-the-art calculations systematically underestimate the phonon energy.
A clear example of a rarely-observed beta-decay selection rule (the Delta(n)=0 rule) has also been observed for the first time and evaluated in detail. The rule has significance for beta-decay half-lives along the r-process pathway, which affects the astrophysical synthesis of heavy nuclei.
Angular correlation measurements between gamma rays have been performed for the experimental setup for the first time in this analysis. This expands its capabilities and could support the proposal of future experiments using the technique.
Exploitation Route The conclusions from this work could be used to support further developments of shell model calculations in order to accurately describe the collective octupole phonon. If this is successful then it could greatly improve predictive capabilities in this region.
Experimentally, the angular correlation method developed here should facilitate easier measurements of this kind in future.
Several promising decays for further observation of the Delta(n)=0 rule are highlighted in this work.
Sectors Other

 
Description CERN@School 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Participation in the CERN@School programme, working alongside the University's Outreach Officer in engaging nearby schoolchildren with particle physics through projects based around a CERN-developed radiation detector. This has involved travelling to the schools involved, demonstrating the use of the equipment, speaking to classes about the projects and applications of nuclear physics in general, and providing support and physics consultancy to the groups as they plan their projects. While there have been no significant projects as of yet, the students have gained hands-on experience of nuclear physics phenomena and the programme has also been improved using feedback from participants.
Year(s) Of Engagement Activity 2017,2018
URL http://www.researchinschools.org/CERN/home.html