Novel technique to study nuclear isomers via atomic processes

B.Q. Lee S.Q. Lim G. Kessedjian 1 C. Sage 1 A. Chebboubi 1 U. Köester 2 M.W. Reed T. Kibédi A.E. Stuchbery
1 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
2 ILL - Institut Laue-Langevin
Abstract : Nuclear isomers can decay through multiple processes; in many cases the dominant mechanism is internal conversion (IC). This is an excitation of an atomic-electron resulting in ionization and the creation of atomic vacancies. These vacancies are propagated towards the outer-shells by the emission of X-rays and Auger electrons. Auger-electron emission increases the ionic charge of decaying ions thus affecting the charge-state distribution. We propose a novel technique to identify and study nuclear isomers by investigating the charge-state distribution of residual ions following isomeric decays. This technique is based on the fact that the residual charge-state distribution is sensitive to the internal conversion coefficient (number of IC events occurring), which could be used to extract useful information about nuclear isomers. As a proof of concept, the technique has been applied to study nuclear isomers in 144Cs. The residual charge-state distribution of 144Cs following isomeric decays has been measured using the Lohengrin fission fragment mass spectrometer at the Institut Laue-Langevin, France [1]. Based on a level scheme proposed in Ref. [1], we simulated the nuclear cascade decays and the subsequent emissions of X-rays and Auger electrons in 144Cs using an Auger cascade model [2]. The simulations started in pre-ionized ions since an equilibrium charge-state distribution (q - 20) was established after the ions passed through a nickel foil 0.3 mm away from the 235U target. The simulation provides very good agreement with the experimental measurement and has enabled the extraction of a limit on the isomeric lifetime, an isomeric ratio, and deduction of the unknown level X [1] to be a state at 92.2 keV.
Document type :
Conference papers
Complete list of metadatas
http://hal.in2p3.fr/in2p3-01368271
Contributor : Emmanuelle Vernay <>
Submitted on : Monday, September 19, 2016 - 12:16:58 PM
Last modification on : Tuesday, May 22, 2018 - 9:48:11 PM

Identifiers

  • HAL Id : in2p3-01368271, version 1

Collections

IN2P3 | LPSC | UGA

Citation

B.Q. Lee, S.Q. Lim, G. Kessedjian, C. Sage, A. Chebboubi, et al.. Novel technique to study nuclear isomers via atomic processes. Heavy Ion Accelerator Symposium for Fundamental and Applied Research (HIAS), Sep 2015, Canberra, Australia. ⟨in2p3-01368271⟩

Export

BibTeX TEI DC DCterms EndNote

Share

Metrics

Record views

84

Contact

CCSD