A HEMT-Based Cryogenic Charge Amplifier with sub-100 eVee Ionization Resolution for Massive Semiconductor Dark Matter Detectors

TL;DR

This paper reports a cryogenic HEMT-based charge amplifier achieving a baseline ionization resolution of 91 eVee, enabling better background discrimination in large semiconductor dark matter detectors for low-mass WIMP detection.

Contribution

It introduces a novel cryogenic charge amplifier with record ionization resolution for massive semiconductor detectors used in dark matter searches.

Findings

Achieved 91 eVee ionization resolution.

First to demonstrate such resolution with large (~150 pF) detectors.

Enhances background discrimination at low recoil energies.

Abstract

We present the measured baseline ionization resolution of a HEMT-based cryogenic charge amplifier coupled to a CDMS-II detector. The amplifier has been developed to allow massive semiconductor dark matter detectors to retain background discrimination at the low recoil energies produced by low-mass WIMPs. We find a calibrated baseline ionization resolution of $\sigma_E = 91\,\text{eV}_{ee}$. To our knowledge, this is the best direct ionization resolution achieved with such massive ($\approx$150 pF capacitance) radiation detectors.