Type of Document	Master's Thesis
Author	Graham, Nicholas L
Author's Email Address	nlgraham@vt.edu
URN	etd-03022006-152203
Title	Gamma Veto Detectors in the KOPIO Experiment
Degree	Master of Science
Department	Physics
Advisory Committee	Advisor Name Title Blecher, Marvin Committee Chair Pitt, Mark L. Committee Member Takeuchi, Tatsu Committee Member
Keywords	kaon CP violation scintillator fiber optics
Date of Defense	2006-02-05
Availability	unrestricted
Abstract KOPIO is an experiment designed to search for the CP-symmetry-violating reaction K^0 -> pi^0+nu+nubar. Measurement of the branching ratio of this reaction, depending on the accuracy of the measurement, could be the most precise measurement of the CP violation parameters of the Standard Model to date. The K^0 -> pi^0+nu+nubar reaction is exceedingly rare, with an expected branching ratio of (3 ± 2)⋅10^(−11) . The rareness of this reaction means two things: 1) that we need prodigious numbers of kaons, and 2) that a multitude of “improper” decays will have to be screened out by means of a veto detector system, part of which is being designed here at Virginia Tech. This detector must be able to detect the passage of daughters of the undesired decay reactions (charged particles and gammas). It must be operational inside a magnetic field, and must have signal timing fast enough to accommodate the rate at which these decays occur. A detector consisting of alternating layers of scintillator and lead, with wavelength-shifting fibers embedded in the scintillator, provides the characteristics sought after. This paper presents methodology used in design and construction of this detector, as well as results of signal property tests, using both cosmic rays and gammas as event triggers. Also included is a discussion on transporting the detector signal outside of the magnetic field so it can be read by photomultiplier tubes resting outside of the sweeping magnet.
Files	Filename       Size       Approximate Download Time (Hours:Minutes:Seconds)     28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access    KOPIO_final.pdf 576.03 Kb 00:02:40 00:01:22 00:01:12 00:00:36 00:00:03

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