Combined γ-ray and electron spectroscopy : study of shape coexistence in 186Pb
Year of publication
2023
Authors
Ojala, Joonas
Abstract
Structures in 186Pb have been under extensive investigation for several decades. 186Pb is the system having a low-lying triplet of zero-spin states, which are assigned with different shapes (spherical, prolate and oblate). This nucleus has been previously studied using α-decay and in-beam γ-ray spectroscopic methods but the transitions near the ground state remained a mystery due to the large conversion coefficient. In this thesis, the low-lying structure of 186Pb was experimentally investigated by combined γ-ray and electron spectrometer, SAGE, and utilising the recoil-decay tagging method. As a result, the E0 2+2 → 2+1 and 4+ 2 → 4+1 interband transitions could be assessed. Also, the feeding of the first excited 0+ 2 state was observed for the first time. Results allowed for reassigning the shapes of 0+ states in 186Pb, which provide input for new theoretical calculations. Recent developments for in-beam γ-ray spectroscopy at the Accelerator Laboratory of Jyväskylä forms part of this thesis work. The properties of the JUROGAM 3 germanium array, such as energy resolution, add-back factor and photopeak detection efficiency, can be found in the fifth chapter. Also, the sum-peak method to determine the absolute photopeak detection efficiency of a germanium array is explained in this chapter. The issue with pile-up marking in the DAQ system is also raised to notify other potential users.
Show moreOrganizations and authors
University of Jyväskylä
Ojala Joonas
Publication type
Publication format
Monograph
Audience
Scientific
MINEDU's publication type classification code
G5 Doctoral dissertation (articles)
Publication channel information
Open access
Open access in the publisher’s service
Yes
Open access of publication channel
Fully open publication channel
Self-archived
No
Other information
Fields of science
Physical sciences
Keywords
[object Object],[object Object],[object Object],[object Object]
Publication country
Finland
Internationality of the publisher
Domestic
Language
English
International co-publication
No
Co-publication with a company
No
The publication is included in the Ministry of Education and Culture’s Publication data collection
Yes