kth.sePublications
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
The short, excited life of tellurium: Lifetime analysis of excited states in the Te midshell region
KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. Uppsala University.ORCID iD: 0000-0001-7578-1241
2024 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

In this licentiate thesis, lifetimes of low lying excited states in the midshell region of tellurium isotopes are discussed. The nuclear lifetimes are interesting properties to study, since they are inversely proportional to the transition probabilities, which contain information on the underlying structure of the nucleus. By measuring the lifetime of a transition, information can be gained on e.g. the collectivity of the state.

The main results presented in this thesis are the lifetime measurements of the 2+ → 0+ and 4+ → 2+ transitions in 118Te described in Paper I. The principal aim of this paper was to reduce the relative uncertainty in the 2+ lifetime, to better see the trend of the 2+ → 0+ transition probabilities over the tellurium isotopic chain.

The work presented in Paper I is based on data from an experiment conducted in 2017 at the JYFL accelerator facility in Jyväskylä, Finland. In this experiment, excited states of were populated in the fusion-evaporation reaction 100Mo(22Ne,4n)118Te at a beam energy of 75 MeV. The lifetimes were extracted using the Recoil Distance Doppler Shift (RDDS) technique, with the Jurogam II γ-ray spectrometer coupled to the Differential Plunger for Unbound Nuclear States (DPUNS). Data analysis was performed using the Differential Decay Curve Method (DDCM) in coincidence mode. The lifetimes were determined to be τ2+ = 7.46(19) ps and τ4+ = 4.25(23) ps, in agreement with previous measurements, but with reduced uncertainty. In the case of the 2+ lifetime, the new result reduces the relative uncertainty of the lifetime from 16% to 2.5%, allowing for more precise tests of theoretical predictions.

In addition to 118Te, an analysis of lifetimes of low-lying excited states in the odd-A nuclei 117Te and 119Te is ongoing and an experiment aiming to measure lifetimes in 116Te has been accepted. These nuclides will also be discussed in this thesis.

Abstract [sv]

I denna licentiatavhandling kommer livstider för lågt liggande exciterade tillstånd i telluriumisotoper att diskuteras. Livstid för ett exciterat tillstånd är intressant att studera eftersom den är omvänt proportionell mot övergångssannolikheten, som innehåller information om den underliggande strukturen i kärnan. Genom att mäta livstiden för en övergång kan man få information om t.ex. tillståndets kollektivitet.

Huvudresultatet som presenteras i denna avhandling är livstidsmätningen av övergångarna 2+ → 0+ och 4+ → 2+ i 118Te som beskrivs i Paper I. Det huvudsakliga syftet med detta arbete var att minska den relativa osäkerheten i 2+-livstiden, för att bättre se trenden för övergångssannolikheterna över isotopkedjan för tellurium. 

Arbetet som presenteras i Paper I är baserat på data från ett experiment utfört 2017 vid acceleratoranläggningen JYFL i Jyväskylä, Finland. I detta experiment populerades exciterade tillstånd i 118Te i kompoundkärne-reaktionen 100Mo(22Ne,4n)118Te, vid en strålenergi på 75 MeV. Livstiderna extraherades med Recoil Distance Doppler Shift (RDDS) tekniken, med Jurogam II-gammaspektrometern kopplad till DPUNS (Differential Plunger for Unbound Nuclear States). Dataanalysen utfördes med Differential Decay curve Method (DDCM) i koincidensläge. Livstiderna bestämdes till  τ2+ = 7.46(19) ps och τ4+ = 4.25(23) ps, i överensstämmelse med tidigare mätning, men med reducerad osäkerhet. När det gäller 2+ livstiden innebär det nya resultatet en minskning av den relativa osäkerheten från 16% till 2,5%, vilket möjliggör mer exakta test av teoretiska förutsägelser.

Utöver 118Te pågår även analysis av livstider hos lågt liggande exciterade tillstånd i de udda-A kärnorna 117Te och 119Te, och ett experiment som syftar till att mäta livstider i 116Te har blivit accepterat. Dessa kärnor kommmer också att diskuteras i denna avhandling.

Place, publisher, year, edition, pages
Stockholm, Sweden: KTH Royal Institute of Technology, 2024. , p. 34
Series
TRITA-SCI-FOU ; 2024:13
Keywords [en]
gamma spectroscopy, lifetime measurement, lifetime, shell model, RDDS, DDCM, nuclear physics, nuclear structure
Keywords [sv]
gamma spektroskopi, livstidsmätningar, livstid, skalmodellen, RDDS, DDCM, kärnfysik, kärnstruktur
National Category
Subatomic Physics
Research subject
Physics, Atomic, Subatomic and Astrophysics
Identifiers
URN: urn:nbn:se:kth:diva-344149ISBN: 978-91-8040-867-7 (print)OAI: oai:DiVA.org:kth-344149DiVA, id: diva2:1844266
Presentation
2024-04-03, FB55, AlbaNova University Centre, Roslagstullsbacken 21, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

QC 2024-03-15

Available from: 2024-03-15 Created: 2024-03-13 Last updated: 2024-03-15Bibliographically approved
List of papers
1. Lifetime measurement of the yrast 2 + state in 118 Te
Open this publication in new window or tab >>Lifetime measurement of the yrast 2 + state in 118 Te
Show others...
2023 (English)In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 59, no 12, article id 300Article in journal (Refereed) Published
Abstract [en]

The electromagnetic transition probabilities of the yrast 2 + states in the midshell Te isotopes, two protons above the closed shell at Sn, are of great importance for the understanding of nuclear collectivity in these isotopes and the role played by the neutron-proton interactions and cross-shell excitations. However, the large uncertainty of the experimental data for the midshell nucleus 118Te and the missing data for 116Te make it difficult to pin down the general trend of the evolution of transition probabilities as a function of the neutron number. In this work, the lifetime of the yrast 2 + state in 118Te was measured, with the aim of reducing the uncertainty of the previous measurement. The result is τ2 += 7.46 (19) ps. In addition, the lifetime of the 4 + state was measured to be τ4 += 4.25 (23) ps. The experimental transition rates are extracted from the measured lifetimes and compared with systematic large-scale shell-model calculations. The trend of the B(E2 ; 0 +→ 2 +) values in the midshell area is in good agreement with the calculations and the calculated B4 / 2 ratio provide evidence for 118Te as a near perfect harmonic vibrator.

Place, publisher, year, edition, pages
Springer Nature, 2023
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-341738 (URN)10.1140/epja/s10050-023-01212-3 (DOI)2-s2.0-85180133905 (Scopus ID)
Note

QC 20240103

Available from: 2024-01-03 Created: 2024-01-03 Last updated: 2024-03-13Bibliographically approved

Open Access in DiVA

Sammanfattning(1563 kB)53 downloads
File information
File name SUMMARY01.pdfFile size 1563 kBChecksum SHA-512
d25c1025da6b60c34c88e4a48e9a04037503ea3bcdf7375623873821bb1c17cc62eba43fa810445a14fe5e2db06b4e3672a5c2b17842c812ce5dc4e7a3246815
Type summaryMimetype application/pdf

Authority records

Ahlgren Cederlöf, Ebba

Search in DiVA

By author/editor
Ahlgren Cederlöf, Ebba
By organisation
Nuclear Physics
Subatomic Physics

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 148 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf