In-situ laser tagging of barium ions in liquid xenon for the EXO experiment

The goal of the Enriched Xenon Observatory (EXO) collaboration is to measure the half-life of neutrino-less double beta decay using a ton size liquid 136Xe detector with zero back-ground. Zero background detection can only be achieved if the daughter nucleus, 136Ba, can be tagged. The EXO collaboration is investigating several techniques to tag the 136Ba daughter. The goal of this thesis is to investigate the prospects of directly observing a single 136Ba+ ion in the liquid using a laser aimed at the decay site, hence in-situ laser tagging. Because the energy levels of Ba+ ions are expected to be altered from the vacuum configuration, in-situ laser tagging can only be accomplished if the spectroscopy of the Ba+ ions in liquid xenon is understood. An ultra-pure liquid xenon test apparatus with a liquid xenon purity monitor has been built to study the spectroscopy of the Ba+ ions. An unexpected discovery of the nonresonant multiphoton ionization of liquid xenon using pulsed UV lasers was made while characterizing the purity monitor. The discovery was vital to the ability to accurately measure the purity of the liquid xenon. The spectroscopy of Ba+ ions in liquid xenon and the multiphoton ionization studies are the two key topics that are presented in this thesis.

Name thesis:degree_name

Doctor of Philosophy (Ph.D.)

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Physics

Grantor dc:publisher

Colorado State University. Libraries

Year dc:date.issued

2012

Authors dc:creator

• Hall, Kendy, author
• Fairbank, William, advisor
• Toki, Walter, committee member
• Marconi, Mario, committee member
• Roberts, Jacob, committee member

Statement dc:rights

• Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.

Language dc:language.iso

eng, English

Identifier URI

https://doi.org/10.25675/3.018319

Identifier

ETDF2012400239PHYS

OAI identifier oai:identifier

oai:mountainscholar.org:10217/67447