Provision of Open-Access Positron Beam Spectroscopy to Canadian Universities (OPEN-POS)

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This proposal requests funds to purchase a radioactive source to supply a high rate of positrons for a slow positron facility, used for acquisition of unique information on advanced materials. As a direct result we will provide open access to the slow positron beam housed at McMaster University: so-called OPEN-POS. Slow positron annihilation spectroscopy (PAS) has for many years provided unique and non-destructive characterization of materials and devices related to the nano-structure of interfaces, point defects and voids. PAS requires the delivery of a high flux of positrons to the material or system under study, and McMaster University houses one of only eight slow positron beams in the world devoted to Materials Science. We will expand the direct use of the positron facility to any Canadian academic (remote user) irrespective of their location, providing an increase in diversity of users (across gender, ethnicity, career-point, and geographical location). In this case we define “remote user” as an individual or group who have complete control of the PAS infrastructure and experiments performed thereon, but are not present at the infrastructure's immediate location. We describe an array of projects from users familiar with PAS, to those new to PAS and including those who are remote to the location of the slow positron beam. The projects include characterization of photonic films, semiconductor materials, 2-D films and photovoltaic devices. Immediate benefits of this work will be improvements in the performance and lowering of the cost of production of integrated optical circuits (used for powering the information superhighway); nanoelectronic circuits and sensors (used in the internet of things); and solar cells (critical in the fight against climate change). The specific request of this proposal is funds for the purchase of a high-flux 22Na positron source. The higher the flux, the greater the number of experiments and users that can be serviced. We have thus requested the highest flux source available. In the exploratory roll-out to be enabled by this proposal we will establish access for four remote users two are early-career researchers at McMaster with no PAS experience; one is experienced with PAS and located at another university in Ontario; one is not experienced with PAS and is located in a different province. Following successful preliminary roll-out, which we anticipate will take one year, our plan is to provide open access to OPEN-POS across Canada to all interested users. We will expand these ideas to accelerate the development of our OPEN-LAB model which will provide access to more infrastructure located at McMaster's central facilities.