First Exploration of Neutron Shell Structure below Lead and beyond N=126

T L Tang; B P Kay; C R Hoffman; J P Schiffer; D K Sharp; L P Gaffney; S J Freeman; M R Mumpower; A Arokiaraj; E F Baader; P A Butler; W N Catford; G de Angelis; F Flavigny; M D Gott; E T Gregor; J Konki; M Labiche; I H Lazarus; P T MacGregor; I Martel; R D Page; Zs Podolyák; O Poleshchuk; R Raabe; F Recchia; J F Smith; S V Szwec; J Yang

doi:10.1103/PhysRevLett.124.062502

First Exploration of Neutron Shell Structure below Lead and beyond N=126

Phys Rev Lett. 2020 Feb 14;124(6):062502. doi: 10.1103/PhysRevLett.124.062502.

Authors

T L Tang¹, B P Kay¹, C R Hoffman¹, J P Schiffer¹, D K Sharp², L P Gaffney³, S J Freeman², M R Mumpower^{4

5}, A Arokiaraj⁶, E F Baader³, P A Butler⁷, W N Catford⁸, G de Angelis⁹, F Flavigny^{10

11}, M D Gott¹, E T Gregor⁹, J Konki³, M Labiche¹², I H Lazarus¹², P T MacGregor², I Martel⁷, R D Page⁷, Zs Podolyák⁸, O Poleshchuk⁶, R Raabe⁶, F Recchia^{13

14}, J F Smith¹⁵, S V Szwec^{16

17}, J Yang⁶

Affiliations

¹ Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
² Department of Physics, University of Manchester, M13 9PL Manchester, United Kingdom.
³ CERN, CH-1211 Geneva, Switzerland.
⁴ Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
⁵ Center for Theoretical Astrophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
⁶ KU Leuven, Intituut voor Kern-en Stralingsfysica, Celestijnenlaan 200D, 3001 Leuven, Belgium.
⁷ Oliver Lodge Laboratory, University of Liverpool, L69 7ZE Liverpool, United Kingdom.
⁸ Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom.
⁹ Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro, Italy.
¹⁰ Institut de Physique Nucléaire, CNRS-IN2P3, Université Paris-Sud, Université Paris-Saclay, 91406 Orsay, France.
¹¹ LPC Caen, Normandie Université, ENSICAEN, UNICAEN, CNRS/IN2P3, 14000 Caen, France.
¹² Nuclear Physics Group, UKRI-STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD, United Kingdom.
¹³ Dipartimento di Fisica e Astronomia, Universit degli Studi di Padova, I-35131 Padova, Italy.
¹⁴ INFN, Sezione di Padova, I-35131 Padova, Italy.
¹⁵ SUPA, School of Computing, Engineering, and Physical Sciences, University of the West of Scotland, Paisley PA1 2BE, United Kingdom.
¹⁶ Department of Physics, University of Jyvaskyla, P.O. Box 35, FI-40014 Jyvaskyla, Finland.
¹⁷ Helsinki Institute of Physics, University of Helsinki, FIN-00014 Helsinki, Finland.

PMID: 32109128
DOI: 10.1103/PhysRevLett.124.062502

Abstract

The nuclei below lead but with more than 126 neutrons are crucial to an understanding of the astrophysical r process in producing nuclei heavier than A∼190. Despite their importance, the structure and properties of these nuclei remain experimentally untested as they are difficult to produce in nuclear reactions with stable beams. In a first exploration of the shell structure of this region, neutron excitations in ^{207}Hg have been probed using the neutron-adding (d,p) reaction in inverse kinematics. The radioactive beam of ^{206}Hg was delivered to the new ISOLDE Solenoidal Spectrometer at an energy above the Coulomb barrier. The spectroscopy of ^{207}Hg marks a first step in improving our understanding of the relevant structural properties of nuclei involved in a key part of the path of the r process.