Study of bound states in 10Be by one neutron removal reactions of 11Be

Jacob Johansen ,J Konki ,Thilo Kroll ,K Wimmer ,María José García Borge ,R Gernhäuser ,L M Fraile ,R Krücken ,V Pesudo ,T Nilsson ,K Riisager ,O Tengblad ,J Pakarinen ,M Seidlitz ,K Nowak ,H Törnqvist ,B Jonson ,V Bildstein ,G T Koldste ,D Mücher ,J Elseviers ,N Warr ,R Raabe ,H O U Fynbo ,J Diriken ,L P Gaffney ,D Voulot ,M Cubero ,H De Witte

doi:10.1088/1361-6471/aa5f28

Abstract

The bound states of 10Be have been studied by removing single neutrons from 11Be nuclei. A 2.8 MeV u–1 beam of 11Be was produced at ISOLDE, CERN and directed on to both proton and deuteron targets inducing one-neutron removal reactions. Charged particles were detected to identify the two reaction channels (d, t) and (p, d), and the individual states in 10Be were identified by gamma detection. All bound states but one were populated and identified in the (d, t) reaction. The combination of REX-ISOLDE and MINIBALL allowed for a clean separation of the high-lying states in 10Be. This is the first time these states have been separated in a reaction experiment. Differential cross sections have been calculated for all the reaction channels and compared to DWBA calculations. Spectroscopic factors are derived and compared to values from the litterature. While the overall agreement between the spectrocopic factors is poor, the ratio between the ground state and the first excited state is in agreement with the previous measured ones. Furthermore, a significant population of the state is observed, which which may indicate the presence of multi-step processes at our beam energy.

Highlights

The study of light nuclei has always presented challenges due to the rapid structural changes encountered here
We are here intersted on the particle bound levels in 10Be, a nucleus that due to its halflife of more than 1 My and its location close to the valley of stability has been studied thoroughly in many previous experiments
This paper presents results from 11Be(d, t) and (p, d) reactions at 2.8 MeV u–1 carried out at the REX-ISOLDE postaccelerator and discusses their relevance for the single-particle structure of 10Be as well as the 11Be ground state

Summary

14 Present address

ISOLDE, PH Department, CERN, CH-1211 Genève, Switzerland. 15 Present address: Department of Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. All bound states but one were populated and identified in the (d, t) reaction. Differential cross sections have been calculated for all the reaction channels and compared to DWBA calculations. Spectroscopic factors are derived and compared to values from the litterature. A significant population of the 2+2 state is observed, which which may indicate the presence of multi-step processes at our beam energy

Introduction

Experiment

Identification of the bound states

Discussion

Summary and conclusion