PICO-500 Dark Matter Detector Design and Construction

The search for dark matter is one of the most interesting fields in physics, with groups at Queen’s and elsewhere working to detect concrete proof of its existence. The PICO collaboration has been developing and running experiments with bubble chambers for direct detection of dark matter for years, building several detectors leading up to its current project, PICO-500. This detector will contain a fiducial mass of 250kg of C3F8 and will search for weakly interacting massive particles (WIMPs), a promising candidate for dark matter. The active fluid is contained within two nested quartz jars installed inside a larger pressure vessel filled with hydraulic oil. With temperature constant, the hydraulics control the pressure within the jars and cause the liquid to become superheated. In this state, the deposition of energy by a WIMP interacting with the C3F8 within the vessel causes boiling. This creates a bubble with position and characteristics that can be observed and quantified. This summer, I worked with PICO’s engineering team on the design and construction of the pneumatic panel, the system that will supply pressurized air PICO-500’s valves and pressure accumulators. I made revisions and added details to the CAD models of the system, sourced parts and materials, and created engineering drawings to allow fabrication of components. As parts arrived, I assembled and adjusted the panel, ensuring physical components matched their 3D models. During downtime, I made drawings for other subsystems of PICO-500. I also assisted in the recommissioning of the Queen’s Test Chamber, a miniature bubble chamber used to test aspects of the PICO detectors in a more accessible environment. Future work will involve final assembly and testing of the valves, regulators and manifolds that make up the pneumatic panel, ensuring they are ready for installation.