Pygmy Dipole States


Polarized 3He Target


UNC Physics

Kamioka Liquid scintillator Anti-Neutrino Detector

While 1015 m-2 neutrinos pass through each one of us each second, most of which lack the common courtesy to stop and interact, many wonder about the utility in studying these standard model wallflowers. Indeed the purpose of the KamLAND detector is to bring the strange properties of these particles into the limelight by studying the antineutrino output from 20 Japanese nuclear reactors. Because antineutrinos are so conservative about their interactions rejecting competing backgrounds is important for observing these reactions, and is the primary focus of TUNL physicists. More than simple rejection, we are interested in position information of passing muons to provide tight limits on the possibility of spurious signals from spallation neutrons. KamLAND's water Cerenkov veto detector allows for a high tagging efficiency using a small number of phototubes by sectioning groups of these detectors in volumes bounded by reflective tyvek surfaces. However, with the possibility of multiple photon reflections, one loses concrete infomation about the position of the photon at creation by the time it reaches a phototube. Our recent work focuses on thoroughly studying the veto efficiency with Monte Carlo simulation, and writing algorithms to track background muons using real and simulated data. To get this real data, each collaboratoir takes shifts, which require 24 hours of travel across the pacific for residents of North Carolina. Of course, the opportunity to speak and learn Japanese abounds as 30% of our collaboration is Japanese, and shifts are taken in the confines of a control room beneath 1km of limestone in a decommissioned Japanese zinc mine. This together with a diet of bento, sushi and ramen allowed physicists toiling over careful analysis to confirm the Large Mixing Angle solution to the solar neutrino problem - a result that has recieved attention from across the physics community.

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