Barium tagging in solid xenon for the EXO experiment

dc.contributor.authorMong, Brian, author
dc.contributor.authorFairbank, William, Jr., advisor
dc.contributor.authorLundeen, Stephen, committee member
dc.contributor.authorBerger, Bruce, committee member
dc.contributor.authorVan Orden, Alan, committee member
dc.description2011 Fall.
dc.descriptionIncludes bibliographical references.
dc.description.abstractNeutrinoless double beta decay experiments are searching for rare decay modes never before observed to uncover the absolute mass of the neutrino, as well as to discover if it is a Majorana fermion. Detection of the daughter nucleus can help provide positive identification of this event over most radioactive backgrounds. The goal of the Enriched Xenon Observatory (EXO) is to measure the rate of 0νββ decay in 136Xe, incorporating 136Ba daughter identification by laser induced fluorescence spectroscopy. Here, we investigate a technique in which the 136Ba daughter is grabbed with a cryogenic probe by freezing it in solid xenon ice, and detected directly in the solid xenon. The absorption and fluorescence spectra of barium in solid xenon were observed for the first time in this work. Identification of the 6s2 1S0 → 6s6p 1P1 transition in both absorption (558 nm) and emission spectra (594 nm) were made. Additional blue absorption and emission lines were observed, but their transitions were not identified. Saturation of the 6s2 1S0 → 6s6p 1P1 transition was not observed with increased excitation rates using resonance excitation at 558 nm. From this a limit on the metastable decay rate was deduced to be greater than 104 s-1. Finally a fluorescence spectrum was obtained from a sample with only 20,000 atoms in the laser beam. With potential improvements of 107 in detection efficiency, single barium atom detection seems possible in solid xenon. A fiber probe detector based on a bare single mode fiber was also constructed and tested with fluorescing dye molecules. Successful detection of a few dye molecules in solution at the probe tip was demonstrated.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.publisherColorado State University. Libraries
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see
dc.subjectdouble beta decay
dc.titleBarium tagging in solid xenon for the EXO experiment
dcterms.rights.dplaThis Item is protected by copyright and/or related rights ( You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). State University of Philosophy (Ph.D.)
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
8.93 MB
Adobe Portable Document Format