Speaker
Description
The Any Light Particle Search~II (ALPS~II) experiment at DESY, Hamburg, is a light-shining-through-a-wall experiment aiming to explore the possible existence of axions and axion-like particles, which are potential dark matter candidates. ALPS~II is currently collecting data using a heterodyne-based detection scheme. A complementary run using a single photon detection scheme is foreseen, which requires a sensor capable of efficiently detecting low-energy photons (1064~nm, 1.165~eV) with a low background rate. To achieve this, we are investigating a tungsten Transition Edge Sensor (TES) developed by NIST. When operated in its superconducting transition at millikelvin temperatures, a single photon absorbed by the TES produces a significant change in its resistance, generating a measurable signal. We have developed simulations of the expected background sources to better understand the background rates affecting the TES. The results of these simulations will be discussed, along with the comparison with measured background data. Beyond axion searches, we are expanding our quantum sensing program to characterize TESs for other physics applications. This includes efforts to measure the even-number photon distribution from a quantum-squeezed light source, highlighting TES potential in quantum optics. Furthermore, we will give an overview of the current status of a direct dark matter search using our TES, which aims to probe MeV-scale dark matter.
| Primary experiment | ALPS II |
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