Apparatus for parity-violation study via capture gamma-ray measurements

The Time Reversal and Parity at Low Energy (TRIPLE) Collaboration uses a sh ort-pulsed longitudinally polarized epithermal neutron beam at the Los Alam os Neutron Science Center to study spatial parity violation (PV) in the com pound nucleus. The typical PV experiment measures the longitudinal cross-se ction asymmetry by the neutron transmission method through thick samples. N eutron capture gamma-ray measurement provides an alternative method for the study of PV, which enables the use of smaller amounts of isotopically pure target material. In 1995 TRIPLE commissioned a new neutron-capture detecto r consisting of 24 pure CsI scintillators arranged in a cylindrical geometr y around the neutron beam. The characteristics and the performance of the d etector and spin transport are described. (C) 1999 Elsevier Science B.V. Al l rights reserved.