The cryogenic photon detection system for the ALPS II experiment: characterization, optimization and background rejection

Abstract

The search for new fundamental bosons at very low mass is the central objective of the ALPS II experiment which is currently set up at the Deutsches-Eleketronen-Synchrotron (Hamburg). This experiment follows the light-shining-through-the-wall concept where photons could oscillate into weakly interacting light bosons in front of a wall and back into photons behind the wall, giving the impression that light can shine through a light tight barrier. In this concept, the background-free detection of near-infrared photons is required to fully exploit the sensitivity of the apparatus. In this project, a Transition-Edge Sensor operated below 100 mK will be used to detect single photons. Characterizatioon, optimization and background rejection have been studied in depth in order to define if the chosen detector will meet ALPS IIc specifications.