Show simple item record

dc.contributor.advisorGarcia, Alejandro
dc.contributor.authorHong, Ran
dc.date.accessioned2016-04-06T16:33:48Z
dc.date.available2016-04-06T16:33:48Z
dc.date.submitted2016-03
dc.identifier.otherHong_washington_0250E_15514.pdf
dc.identifier.urihttp://hdl.handle.net/1773/35630
dc.descriptionThesis (Ph.D.)--University of Washington, 2016-03
dc.description.abstractThe beta-nu of a pure Gamow-Teller beta decay such as the 6He decay is sensitive to tensor-type weak currents predicted by theories beyond the Standard Model. An experiment is developed at University of Washington aiming at measuring the coefficient a_{beta-nu} of 6He decays to the 0.1% level and looking for its deviation from the Standard-Model prediction -1/3 using laser-trapped 6He atoms. The beta particle is detected by a scintillator and a multi-wire proportional chamber, and the recoil ion is detected by a microchannel plate with delay-line anodes for position readouts. a_{beta-nu} is extracted by fitting the measured time-of-flight spectrum of the recoil ions to templates generated by Monte Carlo simulations. This dissertation describes the developments of this experiment for the intermediate goal of a 1% level a_{beta-nu} measurement, such as the detector design, Monte Carlo simulation software, and data analysis frame work. Particularly, detector calibrations are described in detail. The analysis of a 2% level proof-of-principle run in October 2015 is presented as well. Shake-off probabilities for decays of trapped 6He atoms matter for the high-precision a_{beta-nu} measurement. The charge state distribution of recoil ions is obtained by analyzing their time-of-flight distribution using the same experimental setups for the a_{beta-nu} measurement. An analysis approach that is independent of the beta-nu correlation is developed. The measured upper limit of the double shake-off probability is 2x10^{-4} at 90% confidence level. This result is ~100 times lower than the most recent calculation by Schulhoff and Drake. This disagreement is significant for the a_{beta-nu} measurement and needs to be addressed by improved atomic theory calculations.
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.subjectatomic trap; beta decay; radiation detection; shake-off probability; tensor current; weak interaction
dc.subject.otherPhysics
dc.subject.otherNuclear physics and radiation
dc.subject.otherphysics
dc.titleDevelopments for a measurement of the beta-nu correlation and determination of the recoil charge state distribution in 6He beta decay
dc.typeThesis
dc.embargo.termsOpen Access


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record