Exploring the limits of nuclear existence for heavy proton-rich nuclei

Lead Research Organisation: University of Liverpool
Department Name: Physics

Abstract

A fundamental question in nuclear physics is, 'what are the limits on the number of protons and neutrons that can be bound inside an atomic nucleus?' The aim of this research proposal is to answer a vital part of this question by determining more carefully than ever before the precise location of what is known as the proton drip line. The proton and neutron drip lines are the borders between bound and unbound nuclei. Those at the proton drip line have such a large excess of protons that they are highly unstable and try to achieve greater stability through the process of proton emission. We will investigate how nuclear behaviour is affected when protons become unbound. Nuclei along this distant shore of the nuclear landscape should show the greatest deviations from the behaviour expected from predictions of models optimised for more stable nuclei. Our investigations will focus on nuclei close to the proton drip line, for elements between tin (Z=50) and lead (Z=82). Historically, this region has been the primary source of data on proton-emitting nuclei, largely because here the proton emission occurs on an experimentally accessible timescale that still competes effectively with alpha or beta decay. One important feature of the 30 or so proton emitters discovered to date is that they span a wide range of nuclear deformations, ranging from spherical nuclei to others that are rugby ball shaped and are up to 50% longer than they are wide. Proton emission from spherical nuclei is well described using simple models and the simplicity of the theoretical description has allowed a great deal to be learnt about the structure of these nuclei. The theoretical descriptions for proton emission from strongly deformed nuclei are necessarily rather different and several models have been proposed and compared with the available data. We will exploit a new generation of experimental methods to study the most proton-rich atomic nuclei that can be made in the laboratory, spanning the entire range of nuclear deformations. We will search for nuclei presently unknown to science and measure their proton and alpha decays, study excited states in selected nuclei for the first time and extend experimental observations of direct proton emission from heavy nuclei to lifetimes of nanoseconds (billionths of a second!) and even shorter. The results of our experiments will be compared with the theoretical predictions in order to improve our understanding of the complex and fascinating world of the nuclei at the heart of every atom.

Publications

10 25 50
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Andel B (2016) Short-lived isomers in Po 192 and Po 194 in Physical Review C

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Andel B (2017) Detailed a -decay study of Tl 180 in Physical Review C

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Andreyev A (2009) a decay of Pb 180 , 181 in Physical Review C

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Andreyev A (2014) a decay of Au 176 in Physical Review C

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Andreyev A (2009) a decay of At 194 in Physical Review C

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Andreyev A (2010) The new isotope 179 Pb and a-decay properties of 179 Tl m in Journal of Physics G: Nuclear and Particle Physics

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Andreyev A. N. (2013) beta-delayed fission of At-192,At-194 in PHYSICAL REVIEW C

 
Description Nuclear Physics Consolidated Grant
Amount £2,213,696 (GBP)
Funding ID ST/L005670/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Academic/University
Country United Kingdom
Start 08/2014 
End 09/2018
 
Description Nuclear Physics Consolidated Grant
Amount £2,176,557 (GBP)
Funding ID ST/J000094/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Academic/University
Country United Kingdom
Start 08/2011 
End 07/2015
 
Description GREAT 
Organisation University of Jyvaskyla
Country Finland 
Sector Academic/University 
PI Contribution Led design and construction of GREAT. Spokesperson for many experiments.
Collaborator Contribution Contributions to design & constraction of GREAT. Experimental collaborators.
Impact Many publications.
 
Description LISA 
Organisation Daresbury Laboratory
Department Nuclear Physics Support Group
Country United Kingdom 
Sector Academic/University 
PI Contribution Intellectual contributions to experimental research programme.
Collaborator Contribution Intellectual contribution to experimental research programme.
Impact Joint publications.
 
Description LISA 
Organisation University of the West of Scotland
Department School of Physics
Country United Kingdom 
Sector Academic/University 
PI Contribution Intellectual contributions to experimental research programme.
Collaborator Contribution Intellectual contribution to experimental research programme.
Impact Joint publications.
 
Description Research collaborators 
Organisation Daresbury Laboratory
Department Nuclear Physics Support Group
Country United Kingdom 
Sector Academic/University 
PI Contribution Intellectual contributions to research programme and joint research papers.
Collaborator Contribution Intellectual contributions to research programme and joint research papers.
Impact Many joint research papers.
 
Description Research collaborators 
Organisation University of Jyvaskyla
Department Department of Physics
Country Finland 
Sector Academic/University 
PI Contribution Intellectual contributions to research programme and joint research papers.
Collaborator Contribution Intellectual contributions to research programme and joint research papers.
Impact Many joint research papers.
 
Description Research collaborators 
Organisation University of Surrey
Department Department of Physics
Country United Kingdom 
Sector Academic/University 
PI Contribution Intellectual contributions to research programme and joint research papers.
Collaborator Contribution Intellectual contributions to research programme and joint research papers.
Impact Many joint research papers.
 
Description Schools lectures, Liverpool 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach Local
Primary Audience Schools
Results and Impact Many school pupils have attended and asked questions at end of lecture.

Not possible to verify.
Year(s) Of Engagement Activity 2009,2010,2011,2012,2013