Grant: Subatomic Physics Envelope - Research Tools and Instruments

The nEXO experiment is a next generation experiment searching for neutrino-less double beta decay of 136Xenon. The US Department of Energy is ramping up its support of the R to develop an “all silicon” tile (10x10cm^2) solution based on silicon interposer technology of the Fraunhofer Institute for reliability and micro-integration (IZM) in Berlin, Germany. Silicon is one of the only two materials (together with quartz) that appears to be sufficiently radiopure to be used for the SiPM tile. Silicon has also the advantage of perfect thermal matching with the SiPMs that are also made of silicon. We intend to request funds in the next CFI Innovation Fund competition for the construction of nEXO photo-detector plane. This proposal is to support the development of expertise and capabilities for the construction of nEXO tiles in Canada before CFI funds become available. ***The interposer development that we are proposing will be used to prototype tiles of the digital SiPMs (3DdSiPM) being developed by U.Sherbrooke and TRIUMF as an high performance alternative to the baseline analog SiPM solution. The Institute of Micro-Electronics (IME, Beijing, China) is developing an interposer for analog SiPMs but the transmission line specifications are not compatible with the operation of digital electronics on the interposer. The competition between 3DdSiPMs and analog SiPMs is fierce, yet we have a window of opportunity for nEXO to adopt this technology if 3DdSIPMs achieve the required performances by 2021. 3DdSiPMs are expected to shine compared to analog SiPM when it comes to mechanical and electrical integration onto tiles as most of the signal processing occurs within the 3DdSiPMs. With this proposal, our aim is to build a 3DdSiPM tile in order to demonstrate that 3DdSiPMs are truly superior especially when considering large scale integration issue. ***Finally, the silicon interposer technology as a mean of connecting large silicon detectors is likely to find applications outside the detection of photons in liquid Xenon. It would certainly be well suited for use in liquid Argon (DUNE, Dark matter search) provided that it is cost effective. It may also prove compelling associated with silicon pixel detectors. Therefore it is a new technology that may find a wide range of applications in subatomic physics. This grant application is a timely opportunity for Canada to play a pioneering role in the emergence of this technology for use in subatomic physics. ********