Speaker
Description
Noble liquid time projection chambers (TPCs) are of interest for experiments in the quest to answer some most basic questions in both particle and nuclear physics. The charge and light in both LAr and LXe in response to particles of interest are at the limits of detection sensitivity and accuracy of their respective charge sensing electrodes and light sensors, such as silicon photomultipliers (SiPMs). Both will be applied on a large scale in terms of the sensitive areas covered with fine segmentation and large numbers of signal channels. All TPCs under design or planned will depend critically on the use of low noise electronics immersed in the cryogenic liquid (“cold electronics”) to be operated for a decade or longer. Valuable experience has been gained from the already seven years of operation of the TPC with the lowest noise so far, the MicroBooNE. Some highlights of the experience with charge sensing in that TPC will be presented. The two proposed and planned experiments, DUNE second 10-kton LAr module and nEXO 5-ton LXe TPC will present similar charge sensing signal-to-noise challenges, but much more severe light sensing challenges. This is due to the very large areas of SiPMs required. Methods to address the light sensing challenge, to achieve single-photoelectron sensitivity on an array of SiPMs where the avalanche charge signal is deposited on a capacitance of tens of nanofarads, will be described and the results presented.
