Nuclear Structure and Reactions: Theory and Experiment
Lead Research Organisation:
University of Surrey
Department Name: Physics
Abstract
Nuclear physics research is undergoing a transformation. For a hundred years, atomic nuclei have been probed by collisions between stable beams and stable targets, with just a small number of radioactive isotopes being available. Now, building on steady progress over the past 20 years, it is at last becoming possible to generate intense beams of a wide range of short-lived isotopes, so-called 'radioactive beams'. This enables us vastly to expand the scope of experimental nuclear research. For example, it is now realistic to plan to study in the laboratory a range of nuclear reactions that take place in exploding stars. Thereby, we will be able to understand how the chemical elements that we find on Earth were formed and distributed through the Universe. At the core of our experimental research is our strong participation at leading European radioactive-beam facilities: FAIR at GSI, Darmstadt, Germany; SPIRAL at GANIL, Caen, France; and ISOLDE at CERN, Geneva, Switzerland. While we are now contributing, or planning to contribute, to substantial technical developments at these facilities, the present grant request is focused on the exploitation of the capabilities that are now becoming available. To achieve our physics objectives, we also need to use other facilities, including stable-isotope accelerators, since these can provide complementary capabilities. Experimental progress is intimately linked with theory, where novel and practical approaches are a hallmark of the Surrey group. A key and unique feature (within the UK) of our group is our blend of theoretical and experimental capability. Our science goals are aligned with current STFC strategy for nuclear physics, as expressed in detail through the Nuclear Physics Advisory Panel. We wish to understand the boundaries of nuclear existence, i.e. the limiting conditions that enable neutrons and protons to bind together to form nuclei. Under such conditions, the nuclear system is in a delicate state and shows unusual phenomena. It is very sensitive to the properties of the nuclear force. For example, weakly bound neutrons can orbit their parent nucleus at remarkably large distances. This is already known, and our group made key contributions to this knowledge. What is unknown is whether, and to what extent, the neutrons and protons can show different collective behaviours. Also unknown, for most elements, is how many neutrons can bind to a given number of protons. It is features such as these that determine how stars explode. So, we need a more sophisticated understanding of the nuclear force, and we need experimental information about nuclei with unusual combinations of neutrons and protons to test our theoretical ideas and models. Therefore, theory and experiment go hand-in-hand as we push forward towards the nuclear limits. An overview of nuclear binding reveals that about one half of predicted nuclei have never been observed, and the vast majority of this unknown territory involves nuclei with an excess of neutrons. The focus of our activity addresses this 'neutron-rich' territory, exploiting the new capabilities with radioactive beams. Our principal motivation is the basic science, and we contribute strongly to the world sum of knowledge and understanding. Nevertheless, there are more-tangible benefits. For example, our radiation-detector advances can be incorporated in medical diagnosis and treatment. In addition, we provide an excellent training environment for our research students and staff, many of whom go on to work in the nuclear power industry, helping to fill the current skills gap. On a more adventurous note, our special interest in nuclear isomers (energy traps) could lead to novel energy applications. Furthermore, we have a keen interest in sharing our specialist knowledge with a wide audience, and we already have an enviable track record with the media.
Organisations
Publications
Alharbi T
(2015)
Lifetime of the yrast I p = 5 - state and E 1 hindrance in the transitional nucleus Ce 58 136
in Physical Review C
Cerizza G
(2016)
Structure of Sn 107 studied through single-neutron knockout reactions
in Physical Review C
Swan T
(2012)
Discovery of isomers in dysprosium, holmium, and erbium isotopes with N = 94 to 97
in Physical Review C
Ha J
(2020)
Shape evolution of neutron-rich Mo 106 , 108 , 110 isotopes in the triaxial degree of freedom
in Physical Review C
Daniel T
(2017)
? -ray spectroscopy of low-lying excited states and shape competition in Os 194
in Physical Review C
Cáceres L
(2012)
In-beam spectroscopic studies of the 44 S nucleus
in Physical Review C
Crawford H
(2017)
Unexpected distribution of ? 1 f 7 / 2 strength in Ca 49
in Physical Review C
Simpson E
(2012)
Microscopic two-nucleon overlaps and knockout reactions from 12 C
in Physical Review C
De Roubin A
(2017)
Nuclear deformation in the A ˜ 100 region: Comparison between new masses and mean-field predictions
in Physical Review C
Wood R
(2017)
Three-quasiparticle isomer in Ta 173 and the excitation energy dependence of K -forbidden transition rates
in Physical Review C
Freer M
(2012)
Resonances in 11 C observed in the 4 He( 7 Be , a ) 7 Be and 4 He( 7 Be , p ) 10 B reactions
in Physical Review C
Alharbi T
(2013)
Electromagnetic transition rates in the N = 80 nucleus 58 138 Ce
in Physical Review C
Caballero-Folch R
(2017)
ß -decay half-lives and ß -delayed neutron emission probabilities for several isotopes of Au, Hg, Tl, Pb, and Bi, beyond N = 126
in Physical Review C
Rios A
(2014)
Density and isospin-asymmetry dependence of high-momentum components
in Physical Review C
Shubina D
(2013)
Schottky mass measurements of heavy neutron-rich nuclides in the element range 70 = Z = 79 at the GSI Experimental Storage Ring
in Physical Review C
Wimmer K
(2012)
Probing elastic and inelastic breakup contributions to intermediate-energy two-proton removal reactions
in Physical Review C
Johnson R
(2015)
Spin dependence of the incident channel distorted wave in the theory of the A ( d , p ) B reaction
in Physical Review C
Crawford H
(2014)
Shell and shape evolution at N = 28 : The Mg 40 ground state
in Physical Review C
Söderström P
(2013)
Shape evolution in 116 , 118 Ru: Triaxiality and transition between the O(6) and U(5) dynamical symmetries
in Physical Review C
Somà V
(2014)
Chiral two- and three-nucleon forces along medium-mass isotope chains
in Physical Review C
Timofeyuk N
(2015)
Widths of low-lying nucleon resonances in light nuclei in the source-term approach
in Physical Review C
Cunningham E
(2013)
Effect of spin-spin interactions on nucleon-nucleus scattering
in Physical Review C
Mason P
(2012)
Half-life of the I p = 4 - intruder state in 34 P: M 2 transition strengths approaching the island of inversion
in Physical Review C
Orrigo S
(2016)
Observation of the 2 + isomer in Co 52
in Physical Review C
Timofeyuk N
(2013)
Spectroscopic factors and asymptotic normalization coefficients for 0 p -shell nuclei: Recent updates
in Physical Review C
Gade A
(2016)
Single-particle structure at N = 29 : The structure of Ar 47 and first spectroscopy of S 45
in Physical Review C
Smalley D
(2014)
Two-neutron transfer reaction mechanisms in 12 C( 6 He, 4 He) 14 C using a realistic three-body 6 He model
in Physical Review C
Shi Y
(2012)
High- K isomers in neutron-rich zirconium isotopes
in Physical Review C
Muto S
(2014)
Magnetic properties of Hf 177 and Hf 180 in the strong-coupling deformed model
in Physical Review C
Waldecker S
(2016)
Implications for ( d , p ) reaction theory from nonlocal dispersive optical model analysis of Ca 40 ( d , p ) Ca 41
in Physical Review C
Goddard P
(2015)
Fission dynamics within time-dependent Hartree-Fock: Deformation-induced fission
in Physical Review C
Morales A
(2013)
ß -delayed ? -ray spectroscopy of 203 , 204 Au and 200 - 202 Pt
in Physical Review C
Walshe J
(2016)
Experimental study of high-lying states in Mg 28 using the resonant elastic scattering of a particles
in Physical Review C
Lalkovski S
(2013)
Core-coupled states and split proton-neutron quasiparticle multiplets in 122 - 126 Ag
in Physical Review C
Gade A
(2016)
One-neutron pickup into Ca 49 : Bound neutron g 9 / 2 spectroscopic strength at N = 29
in Physical Review C
Pardi C
(2013)
Continuum time-dependent Hartree-Fock method for giant resonances in spherical nuclei
in Physical Review C
Pérez-Cerdán A
(2013)
Deformation of Sr and Rb isotopes close to the N = Z line via ß -decay studies using the total absorption technique
in Physical Review C
Rios A
(2017)
Comparison of nuclear Hamiltonians using spectral function sum rules
in Physical Review C
Molina F
(2015)
T z = - 1 ? 0 ß decays of Ni 54 , Fe 50 , Cr 46 , and Ti 42 and comparison with mirror ( He 3 , t ) measurements
in Physical Review C
Milne S
(2016)
Mirrored one-nucleon knockout reactions to the T z = ± 3 2 A = 53 mirror nuclei
in Physical Review C
Tostevin J
(2014)
Systematics of intermediate-energy single-nucleon removal cross sections
in Physical Review C
Matta A
(2015)
New findings on structure and production of He 10 from Li 11 with the ( d , He 3 ) reaction
in Physical Review C
Johnson R
(2014)
Adiabatic model of ( d , p ) reactions with explicitly energy-dependent nonlocal potentials
in Physical Review C
Carbone A
(2013)
Self-consistent Green's functions formalism with three-body interactions
in Physical Review C
Brown S
(2012)
Low-lying neutron f p -shell intruder states in 27 Ne
in Physical Review C
Mutschler A
(2016)
Spectroscopy of P 35 using the one-proton knockout reaction
in Physical Review C
Hlophe L
(2013)
Separable representation of phenomenological optical potentials of Woods-Saxon type
in Physical Review C
Wu X
(2017)
Systematic study of multi-quasiparticle K -isomeric bands in tungsten isotopes by the extended projected shell model
in Physical Review C
Browne F
(2017)
K selection in the decay of the ( ? 5 2 [ 532 ] ? 3 2 [ 411 ] ) 4 - isomeric state in Zr 102
in Physical Review C
Description | We have advanced the following areas: understanding the limits of the nuclear landscape, especially the neutron-rich limits; understanding and exploiting the reactions needed to reach the limits; studying and understanding novel structures observed on approaching the limits; engaging fully with the international community of nuclear physicists; disseminating results through leading journals and conferences; providing excellent training. |
Exploitation Route | The main beneficiaries of this work will be the national and international nuclear physics communities. In addition, the expected results on shell structure and isomeric states will also be of significant interest to the nuclear-astrophysics and isomer-application communities. We have an active involvement and information exchange with both these nuclear structure 'user' communities. The isomer work also links closely to the atomic physics community, in particular through the study of highly charged ions stored in rings and traps. Our theoretical methods will be of interest to the condensed-matter community, especially in relation to pairing condensates. The work on detector development has wide potential applications for medical diagnosis and treatment. The research will also provide manpower trained to a high level (PhDs and PDRAs with a deep understanding of radiation physics and sensor technologies) who may subsequently be employed in many different areas, such as national security, the nuclear power industries, environmental monitoring and control, and medical physics. |
Sectors | Education,Energy,Environment,Healthcare,Security and Diplomacy |
Description | No specific non-academic impact has yet become material. |