Speaker
Description
At low energy frontier among the Standard Model testing methods and searches for new physics beyond it are precision spectrum shape and correlation coefficient measurements in nuclear and neutron beta decay. For identification and 3D-tracking of low-energy electrons a special type of gas-based detector was designed that minimizes scattering and energy loss. In the first approach the gas tracker was successfully used in the miniBETA project to study tiny effects in beta spectrum shape on the allowed Gamow-Teller transitions. The miniBETA spectrometer consists of a hexagonally structured multi-wire drift chamber (MWDC), filled with a mixture of helium and isobutane gas and a plastic scintillator serving as a trigger source and energy detector. The drift time information is used to track particles in the plane perpendicular to the wires, while a charge division technique provides spatial information along the wires. Inspired by the performance of this tracker we are building a Mott polarimeter to be used in the ultimate phase of the BRAND experiment to study the neutron decay correlation coefficients. In this contribution, measurement techniques, detector stability, applied front-end electronics and current challenges for both experiments will be discussed.
