Thin Films for the Transport of Polarized Ultracold Neutrons for Fundamental Symmetry Study

The use of ultracold neutrons (UCN) to study fundamental parameters such as the neutron lifetime and decay correlations in polarized neutron beta decay are poised to make significant contributions to our understand of the Standard Model and its extensions. To this end, the UCNA experiment is pursuing a precision measurement (0.2%) of the angular correlation between the neutron spin and the direction of emission of the electron in polarized neutron decay (the ``A'' asymmetry). The UCNA experiment makes use of the spallation-driven solid deuterium (SD2) UCN source at the Los Alamos Neutron Science Center (LANSCE). The UCN leave the source and are 100% polarized by passing through a strong magnetic field before their decay is observed by a very sensitive electron spectrometer. UCN guides facilitate the transfer of UCN from the source to the spectrometer. Common guide materials include stainless steel, copper, aluminum, and quartz. Often a thin film is applied to these components to increase their ability to transport/bottle and preserve the polarization of UCN. In the region of the SD2 UCN source, nickel-58 films are applied, whereas once the UCN are polarized, diamond-like carbon (DLC) films are employed. This dissertation covers the application, process developments, and characterization of these coatings. In addition a study concerning the surface finish resulting from the mechanical polishing and electropolishing of the guides that make up the UCNA beamline is presented.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Physics

Department dc:contributor.department

Physics

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2010

Author dc:creator

• Mammei, Russell Rene

Chair dc:contributor.committeechair

• Vogelaar, R. Bruce

Committee members dc:contributor.committeemember

• Heremans, Jean J.
• Pitt, Mark L.
• Khodaparast, Giti A.

• Neutron Beta Decay
• Polarized Ultracold Neutrons
• Standard Model Tests
• Diamond-Like Carbon
• Polarized Neutron Guides
• Pulsed Laser Deposition
• Ebeam Evaporation
• Electropolishing
• Mechanical Polishing
• Surface Roughness

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-08182010-112705

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/28714