he COUPP-60 experiment, located at SNOLAB, had a breath taking morning on May 01 as it experienced the first bubble in the experiment chamber!The COUPP collaboration uses bubble chambers to search for dark matter in the form of Weakly Interacting Massive Particles, or WIMPs. The bubble chamber fluid, CF3I is superheated so that the recoiling nucleus from a scattering WIMP will nucleate a single bubble (leave a small amount of energy behind that creates a bubble).
At this low level of superheat, the bubble chamber is completely insensitive to the gamma-ray and beta-decay backgrounds that plague other dark matter detectors. Alpha decays in the target fluid do nucleate bubbles, but these are distinguished from WIMP interactions based on their ultrasonic acoustic signature.
Dr. Eric Vazquez-Jauregui, SNOLAB researcher, expressed his delight at the experiment milestone and was thankful to the many people who helped get the COUPP detector to this stage. Dark matter is believed to make up about 25% of the mass of the Universe and is fundamental to the structure and evolution of galaxies, including our own. While it appears to have no interactions with ordinary matter that produces light, it does interact with gravity and that gravitational interaction shapes and holds together galaxies and even clusters of galaxies.
COUPP is expecting many exciting weeks to come!