A HEMT-Based Cryogenic Charge Amplifier with sub-100 eVee Ionization   Resolution for Massive Semiconductor Dark Matter Detectors
  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. 
A. Phipps, A. Juillard, B. Sadoulet, B. Serfass, Y. Jin
physics.ins-det astro-ph.IM