Speaker
Dr
Sergey pereverzev
(LLNL)
Description
Abstract.
In experiments aiming to measure interactions at low energies —exemplified by neutrino-nucleus coherent scattering experiments and the quest for light-mass dark matter particles—researchers must understand the underlying noise mechanisms in their detectors. A review of literature and measurements in detectors at LLNL reveal patterns among low-energy detector backgrounds which invite questions about specific effects in materials under energy flow conditions. Residual radioactivity and cosmogenic radiation lead to slow accumulation of energy in detector materials, in the form of long-living excitations and trapped ions. We hypothesize that the relaxation of this energy occurs in a non-equilibrium, punctuated manner, resulting in avalanche-like ionization or scintillation events which mimic the sought for low-energy particle interactions. In dual-phase detectors, solid Xe and Ar are inevitably present in the form of physiosorbed solid films on internal surfaces. As a consequence, effects like thermally stimulated luminescence, thermally stimulated electron emission and related phenomena are embedded in detector’s design. Production mechanisms for excitations and trapped charges, their interactions and avalanche-like destruction processes appear differently in different materials. Nonetheless, a common dynamical model —called self-organized criticality— allows us to identify underlining process and, in some cases, to suppress or mitigate unwanted consequences.
Interestingly, a similar model can be applied to quantum and superconducting detectors yielding an unexpected crosspollination between quantum information and high energy physics.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344; we acknowledge LDRD grant 17-FS-029.
Primary author
Dr
Sergey pereverzev
(LLNL)
