A Mott polarimeter for the search of time reversal violation in the decay of free neutrons

Abstract : A new polarimeter for low-energy electrons has been built and tested. The device was developed for the measurement of the transverse polarization of beta particles emitted in the decay of polarized cold neutrons. The decay electrons are identified by multi-wire proportional chambers made of low-Z materials and are detected with plastic scintillator hodoscopes. The transverse polarization is analyzed by means of large angle Mott scattering on a thin Pb foil. We describe here the elements of the apparatus and present the results of test measurements which illustrate its performance.