Studies of ultracold neutron dynamics and systematic effects for the TUCAN EDM experiment
department or school: Science, Faculty of
department or school: Physics and Astronomy, Department of
data provider: DSpace
degree campus: UBCV
creator: Vanbergen, Sean
issued: 2025-04-25T17:36:30Z
issued: 2025
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: The TRIUMF UltraCold Advanced Neutron (TUCAN) collaboration is developing a new measurement of the neutron electric dipole moment (nEDM) with the goal of improving the current best limit of dn ≤ 1.8 × 10-²⁶ ecm (90% C.L.) to the level of dn ≲ 2 × 10-²⁷ ecm (90% C.L.). A non-zero nEDM requires the violation of charge-parity (CP) symmetry, and so the measurement of the nEDM can shed light on unanswered questions of fundamental physics, such as baryon asymmetry, the strong CP problem, and extensions of the Standard Model.The first part of this dissertation relates to the development of a new source of ultracold neutrons (UCNs). This source is based on the conversion of cold neutrons produced by a dedicated spallation source to UCNs by downscattering in superfluid ⁴He. The new source will enable the desired statistical reach of the experiment. Prior to the construction of the new source, a prototype source was operated at TRIUMF from 2017 to 2019, and was used to perform experiments on UCN production, storage, and transport to assist in the design of the new source. This dissertation describes the results of a subset of those experiments, relating to the production and lifetime of UCNs in superfluid 4He. The second part of this dissertation relates to the design of the TUCAN EDM spectrometer, which implements Ramsey’s method of separated oscillating magnetic fields to search for a shift in precession frequency associated with the presence of a non-zero nEDM in a large electric field. To achieve the desired sensitivity, the spectrometer must be designed to minimize systematic uncertainties. The calculations and simulations described here demonstrate the requirements to achieve this goal. This work is largely focused on the design of the central region of the spectrometer, which contains the UCNs and applies the electric field. The work done on the central region includes the development of a prototype cell and characterization of its storage properties, simulation studie…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/90801
note: Studies of Ultracold Neutron Dynamics andSystematic Effects for the TUCAN EDMExperimentbySean VanbergenB.A.Sc., The University of British Columbia, 2015B.C.S., The University of British Columbia, 2018A THESIS SUBMITTED IN PARTIAL FULFILLMENT OFTHE REQUIREMENTS FOR THE DEGREE OFDOCTOR OF PHILOSOPHYinThe Faculty of Graduate and Postdoctoral Studies(Physics)THE UNIVERSITY OF BRITISH COLUMBIA(Vancouver)April 2025c© Sean Vanbergen 2025The following individuals certify that they have read, and recommend to the Faculty of Graduateand Postdoctoral Studies for acceptance, the thesis entitled:Studies of Ultracold Neutron Dynamics and Systematic Effects for the TUCAN EDMExperimentsubmitted by Sean Vanbergen in partial fulfillment of the requirements forthe degree of Doctor of Philosophyin PhysicsExamining Committee:Ruediger Picker, Research Scientist, TRIUMFCo-supervisorKirk Madison, Professor, Physics and Astronomy, UBCCo-supervisorScott Oser, Professor, Physics and Astronomy, UBCUniversity ExaminerWilliam Andrew MacFarlane, Chemistry, UBCUniversity ExaminerBrad Plaster, Professor, Physics and Astronomy, University of KentuckyExternal ExaminerAdditional Supervisory Committee Members:Douglas Bryman, Professor, Physics and Astronomy, UBCSupervisory Committee MemberDouglas Scott, Professor, Physics and Astronomy, UBCSupervisory Committee MemberReiner Kruecken, Nuclear Science Division Director, Lawrence Berkeley National LaboratorySupervisory Committee MemberiiAbstractThe TRIUMF UltraCold Advanced Neutron (TUCAN) collaboration is developing a new mea-surement of the neutron electric dipole moment (nEDM) with the goal of improving the currentbest limit of dn ≤ 1.8×10−26 ecm (90% C.L.) to the level of dn . 2×10−27 ecm (90% C.L.). Anon-zero nEDM requires the violation of charge-parity (CP) symmetry, and so the measurementof the nEDM can shed light on unanswered questions of fundamental physics, such as baryonasymmetry, the strong CP problem, and extensions of the Standard Model.The…
has type: Thesis/Dissertation
date issued: 2025-05
is shown at: 10.14288/1.0448591
language: eng
degree discipline: Physics
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Picker, Ruediger
contributor: Madison, Kirk W., 1969-
type: Text
identifier URI: http://hdl.handle.net/2429/90801