Precision neutron polarimetry for neutron beta decay

Conference · Thu Jan 01 04:00:00 EST 2004

DOI:https://doi.org/10.6028/jres.110.045· OSTI ID:977698

Penttila, S I ^[1]; Bowman, J D ^[2]

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1. Seppo I.
2. J. David

The abBA collaboration is developing a new type of field-expansion spectrometer for measurement of the three correlation coefficients a, A, and B and shape parameter b. The measurement of A and B requires precision neutron polarimetry. We will polarize a pulsed cold neutron beam from SNS using a {sup 3}He neutron spin filter. The well-known polarizing cross section for n-{sup 3}He has 1/v dependence, which is used to determine the absolute beam polarization through a time-of-flight (TOF) measurement. We show that measuring the TOF dependence of A and B, the coefficients and the neutron polarization can be determined with small loss of statistical precision and negligible systematic error. We conclude that it is possible to determine the neutron polarization averaged over a run in the neutron beta decay experiment to better than 10{sup -3}. We discuss various sources of systematic uncertainties in the measurement of A and B and conclude that they are less than 10{sup -4}.

• Research Organization: Los Alamos National Laboratory
• Sponsoring Organization: DOE
• OSTI ID: 977698
• Report Number(s): LA-UR-04-4201
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCURACY
BETA DECAY
COLD NEUTRONS
CROSS SECTIONS
NEUTRONS
POLARIMETRY
POLARIZATION
SHAPE
SLOW NEUTRONS
SPECTROMETERS
SPIN