A low-background detector for the study of electron-antineutrino interactions on deuterons and protons

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7157729

Riley, S P

The subject of this dissertation is a detector system capable of a high-precision measurement of the cross section for the disintegration of the deuteron via neutral and charged current interactions with reactor antineutrinos ([bar [nu]][sub e]d [yields] [bar [nu]][sub e]pn and [bar [nu]][sub e]d [yields] e[sup +]nn). In the past, the background to this reaction due to cosmic-rays interacting in the surrounding materials was high-around 300 per day-compared to the signal rate of 50 per day. It will be shown that improvements to the active and passive shielding, as well as improvements to the data collection system have reduced this background rate to less than 50 per day. Based on the measured backgrounds, an experimental precision of 4% is extrapolated for the determination of the isovector-axialvector coupling constant ([beta]) of the hadronic weak neutral current. At the low energies available at a nuclear reactor, the neutral current disintegration cross section is directly proportional to the square of this coupling constant and is independent of the other possible couplings. In the standard electroweak theory of Weinberg and Salam, the isovector-axialvector coupling is independent of the Weinberg angle, thus measurement of the neutral current disintegration provides an unambiguous test of this component of the theory. An improved method of detecting neutrino-oscillation using the ratio of measured to predicted cross sections for the neutral and charged current reactions is also explored. By measuring the cross section for the charged current reaction on the proton instead of the deuteron, it will be shown that the experimental uncertainty in the ratio of cross sections can be reduced to the 1% level.

• Research Organization: California Univ., Irvine, CA (United States)
• OSTI ID: 7157729
• Country of Publication: United States
• Language: English

Related Subjects

440104 -- Radiation Instrumentation-- High Energy Physics Instrumentation
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
662320* -- Neutrino Interactions-- (1992-)
662340 -- Hadron Interactions-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANTINEUTRINO-ELECTRON INTERACTIONS
BARYONS
CHARGED PARTICLES
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DETECTION
DEUTERON REACTIONS
DEUTERONS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
INTERACTIONS
LEPTON-LEPTON INTERACTIONS
NEUTRINO DETECTION
NEUTRINO-ELECTRON INTERACTIONS
NUCLEAR REACTIONS
NUCLEONS
PARTICLE INTERACTIONS
PROTONS
RADIATION DETECTION