Detection capability of Migdal effect for argon and xenon nuclei with position sensitive gaseous detectors

TL;DR

This study explores the potential for detecting the Migdal effect in argon and xenon gases using small, position-sensitive gaseous detectors, aiming to enable experimental observation crucial for advancing dark matter research.

Contribution

It demonstrates through simulations that a tabletop gaseous detector can observe the Migdal effect with manageable background, paving the way for experimental detection.

Findings

Detectable event rates of 100-1000 per day in small detectors.

Background sources like neutrons and gamma-rays are significantly higher than Migdal signals.

Good background understanding and reduction are essential for successful detection.

Abstract

Migdal effect is attracting interests because of the potential to enhance the sensitivities of direct dark matter searches to the low mass region. In spite of its great importance, the Migdal effect has not been experimentally observed yet. A realistic experimental approach towards the first observation of the Migdal effect in the neutron scattering was studied with Monte Carlo simulations. In this study, potential background rate was studied together with the event rate of the Migdal effect by a neutron source. It was found that a table-top sized $\sim (30\rm cm )^3$ position-sensitive gaseous detector filled with argon or xenon target gas can detect characteristic signatures of the Migdal effect with sufficient rates (O($10^2\sim10^3$) events/day). A simulation result of a simple experimental set-up showed two significant background sources, namely the intrinsic neutrons and the neutron induced gamma-rays. These background rates were found to be much higher than those of the Migdal effect in the neutron scattering. As a consequence of this study, it is concluded that the experimental observation of the Migdal effect in the neutron scattering can be realized with a good understanding and reduction of the background.