Cryogenic instrument could spot theoretical dark matter particles
Cryogenic instrument could spot theoretical dark matter particles lead image
Physicists are on the hunt for a theoretical particle that could solve the strong CP (charge conjugation-parity) problem and be a candidate for dark matter. One place where scientists are looking for these elusive particles, called axions, is the sun, where they are thought to be produced when X-rays scatter off electrons and protons.
Vaccaro et al. detailed a detector and readout technology that could be used in an axion helioscope. The instrument is composed of a transition-edge sensor (TES) micro-calorimeter array readout by means of a frequency-domain multiplexing (FDM) technique.
An axion entering the helioscope would be converted into an X-ray photon by large magnets. This photon would be detected by the TES by measuring the minute temperature change when the X-ray is absorbed in one of the array elements.
“The amplitude of the pulse measured by the TES is then used to estimate the energy of the photon, with an extreme level of precision that only cryogenic instruments can grant,” said author Davide Vaccaro.
The instrument was tested in a laboratory setup by measuring the X-ray background rate. The experiment showed promising results, even without any specific optimization of the setup. The authors describe necessary developments required to satisfy the background rate requirements for a final instrument.
“We’re very excited about this first proof of concept that TES and FDM could be effectively used in a solar helioscope, in complementary operation with the already established non-cryogenic microMEGAS detectors,” Vaccaro said.
The authors are working on further improvements to their TES and FDM technologies, such as scaling up to a multiplexing factor of more than 70, for future applications in astronomy and particle physics.
Source: “Background rates of x-ray transition-edge sensor micro-calorimeters under a frequency domain multiplexing readout for solar axion-like particles’ detection,” by D. Vaccaro, L. Gottardi, H. Akamatsu, J. van der Kuur, K. Nagayoshi, E. Taralli, M. de Wit, K. Ravensberg, J. R. Gao, and J. W. A. den Herder, Review of Scientific Instruments (2023). The article can be accessed at https://doi.org/10.1063/5.0142367 .
