PICO - A Bubble Chamber for Dark Matter Detection

A bubble forms in PICO-40 during a commissioning run
One of four camera views of a bubble forming in PICO-40L.

PICO is a liquid-based dark matter detector. Its name comes from the merging of two previously independent experiments, PICASSO and COUPP. PICASSO (Project in CAnada to Search for Super-symmetric Objects) and COUPP (the Chicagoland Observatory for Underground Particle Physics) both had the same basic strategy: create a liquid target that is resting very close to its boiling point, so that even small amount of energy deposited in the liquid will cause it to boil. PICO advances that concept to the next generation with larger targets and enhanced sensitivity to even gentle interactions between a subatomic particle and the fluid. This is part of a more generic technology known as a "bubble chamber," owing to the fact that the boiling creates a local pocket of gas - a bubble - wherever the particle interaction occurs.

Dark matter is just such a particle that we would like to detect. Multiple independent lines of evidence for the existence of a non-luminosity and gravitating form of matter have accumulated over the last century. The constituents of this matter are still unknown. Dark matter detectors of any kind seek to shed light on those constituents ... if they can be detected by any means other than gravity. The PICO program is currently constructing a second phase PICO-40L (40 litre) detector and is planning to construct soon PICO-500 (a 500 litre detector).

My current role is to support the experiment through construction, operation, and commissioning activities. I am also becoming involved in monitoring and related software, and I have a long term interest in bubble detection (include tried-and-true methods and novel ideas at the intersection of acoustics and machine learning). 

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