A Detector Testing Chamber for the Nab Experiment

The Nab experiment will study the decay electrons and protons from neutron beta decay to measure the vector to axial vector coupling ratio and search for BSM physics. It will use pixelated silicon detectors to detect these decay particles. It is important to characterize the timing and energy response of these detectors as a function of position within a pixel to understand the systematic errors. We report on the design of a detector testing chamber with a calibration source coupled to a timing detector assembly.

This assembly will be used to give us a known energy and timing output that we can compare to our measured signals. A 2-dimensional stage will be used to position the assembly in front of the detector to study the position-dependent response of each pixel and its neighbors. We will present the current design and implementation of this source positioner.