Title: TPC without charge multiplication: a CMOS direct readout towards
neutrinoless double-beta decay and other applications.

Speaker: Yuan Me (LBNL)

Abstract

Time Projection Chamber (TPC) and silicon-based sensor/Integrated Circuitry (IC) are indispensable elements in modern detector instrumentation. Since its inception, TPC relied on the charge sensing and high-speed sampling capabilities offered by silicon devices. The charge collection elements and the electronics, however, are traditionally separated. We are developing a new kind of TPC by integrating an array of CMOS charge sensors directly into the detection medium. Each CMOS sensor has exposed metal pads (pixels) for direct charge collection, and contains charge sensitive amplifiers as well as digitization/signal processing/data transmission circuitry. For the application in Neutrinoless Double-Beta Decay search in high-pressure gas, the electronic noise is suppressed to a level that the required signal-to-noise ratio is achieved without the need of avalanche charge multiplication. It provides competitive energy resolution while improves on tracking capability, stability, and scalability compared to alternative readout schemes. Moreover, ions drifting in gas can be read directly since the otherwise prohibitive ion avalanche is unnecessary. It enables the use of alternative gases
and double-beta decay candidate isotopes such as SeF6 gas, in which only ion drifting is possible. With modest modifications, the readout plane could be used in liquid noble gas and organic liquid TPCs for a broad range of applications. The design and the progress of the first prototype will be presented.