eprintid: 36946
rev_number: 7
eprint_status: archive
userid: 9107
dir: disk0/00/03/69/46
datestamp: 2025-07-29 13:29:17
lastmod: 2025-07-29 13:30:34
status_changed: 2025-07-29 13:29:17
type: doctoralThesis
metadata_visibility: show
creators_name: Bezrodnova, Olesia
title: High-precision Penning-trap Measurement of the Helium-3 Atomic Mass
subjects: ddc-530
divisions: i-130200
adv_faculty: af-13
keywords: Penning-trap, Mass-spectrometry, ion trap
cterms_swd: Spektrometrie
cterms_swd: Ion
cterms_swd: Präzession
abstract: This work presents a high-precision atomic mass measurement of helium-3. The measurement was performed using the Penning-trap mass spectrometer Liontrap, where the cyclotron frequency of the helium ion was measured relative to that of a carbon ion, which serves as a standard in atomic mass units. With a relative uncertainty of 1.2 × 10−11, this result represents the most precise mass measurement of helium-3 in atomic mass units to date. It contributes to resolving the “Light Ion Mass Puzzle” - inconsistencies in the measured masses of light nuclei, namely the proton, deuteron, and helium-3, reported by different Penning-trap mass spectrometers in the past. By demonstrating consistency between the results from Liontrap and those from the group at Florida State University, while simultaneously highlighting a discrepancy with the results from the University of Washington (UW), this work suggests that the earlier Penning-trap measurements by the UW group may have underestimated the uncertainty in their results. Consequently, confidence in Penning-trap measurements
of light ion masses - fundamental constants used to test the validity of the Standard Model - is restored.

During the course of this work, the experimental setup was upgraded to allow for the production of helium-3 ions and an improved detection system. Additionally, a new analysis approach was introduced, which effectively suppresses the dominant systematic effect observed in previous Liontrap measurements, the lineshape effect, by a factor of more than 100. Furthermore, a phase-sensitive method for measuring
the axial frequency has been developed, showing promising potential for improving the statistical precision achievable in Penning-trap experiments in general.

The measurement presented in this thesis concludes a series of studies on light ions conducted at Liontrap, and the experimental setup is now being repurposed
for lepton symmetry tests at MPIK.
date: 2025
id_scheme: DOI
id_number: 10.11588/heidok.00036946
own_urn: urn:nbn:de:bsz:16-heidok-369468
date_accepted: 2025-06-23
advisor: HASH(0x55602a66e008)
language: eng
bibsort: BEZRODNOVAHIGHPRECIS20250708
full_text_status: public
place_of_pub: Heidelberg
citation:   Bezrodnova, Olesia  (2025) High-precision Penning-trap Measurement of the Helium-3 Atomic Mass.  [Dissertation]     
document_url: https://archiv.ub.uni-heidelberg.de/volltextserver/36946/1/Dissertation_Bezrodnova.pdf