G5 Doctoral dissertation (article)
Combined γ-ray and electron spectroscopy : study of shape coexistence in 186Pb (2023)

Ojala, J. (2023). Combined γ-ray and electron spectroscopy : study of shape coexistence in 186Pb [Doctoral dissertation]. University of Jyväskylä. JYU dissertations, 604. http://urn.fi/URN:ISBN:978-951-39-9288-0

JYU authors or editors

Publication details

All authors or editorsOjala, Joonas


Journal or seriesJYU dissertations


Publication year2023

Number in series604

Number of pages in the book1 verkkoaineisto (84 sivua, 10 numeroimatonta sivua)

PublisherUniversity of Jyväskylä

Place of PublicationJyväskylä

Publication countryFinland

Publication languageEnglish

Persistent website addresshttp://urn.fi/URN:ISBN:978-951-39-9288-0

Publication open accessOpenly available

Publication channel open accessOpen Access channel


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.

Keywordsspectroscopygamma radiationelectronsdoctoral dissertations

Free keywordsshape coexistence; conversion electron spectroscopy; γ-ray spectroscopy; SAGE; JUROGAM 3

Contributing organizations

Ministry reportingYes

Reporting Year2023

Last updated on 2024-15-05 at 13:01