The Cryogenic Dark Matter Search has gone through a number of major changes over the years. In 2002, operations moved from Stanford University to the Soudan Mine in Minnesota. In 2010, the CDMS collaboration installed more advanced germanium detectors and renamed itself SuperCDMS.
And in 2019, the experiment will begin a new phase in the underground Canadian laboratory SNOLAB.
Fermilab scientist Dan Bauer will lead the SuperCDMS collaboration through this upcoming transition as its recently elected spokesperson. He began his three-year term in May, taking over from Blas Cabrera of Stanford University. Prior to his role as spokesperson, Bauer served CDMS and SuperCDMS as project manager and project scientist for 13 years.
SuperCDMS is one of several experiments around the world that is on the hunt for dark matter, hypothesized invisible stuff that holds galaxies together. SuperCDMS’ goal is to detect it in the form of WIMPs: weakly interacting massive particles. The experiment will focus particularly on light WIMPS, with masses less than 10 times the mass of the proton.
Bauer’s main goal is to make sure the move to SNOLAB, whose cleaner environment and greater depth beneath ground will help reduce backgrounds in the experiment, goes off smoothly.
It’s not a matter of popping the experiment on a truck and sending it on its way to Ontario. One major piece of the transition is building a considerably larger, more complicated cryogenic system to lower the sensors’ temperature from 50 millikelvin, their temperature in Soudan, to a mere 15 millikelvin. Colder sensors and improved shielding will allow the detectors to be more sensitive to potential dark matter interactions.
“We’ve been doing a lot of physics at Soudan, and switching to a new site is always a challenge,” Bauer said. “We want to be set up to do the best possible experiment at SNOLAB.”
Bauer is working to add new institutions to the collaboration, including SNOLAB. He is also in discussions with members of two similar experiments in Europe (Edelweiss and CRESST) to bring their detectors to SuperCDMS SNOLAB.
The SuperCDMS collaboration currently has members from 21 institutions, including SLAC National Accelerator Laboratory (the project managing institution), Pacific Northwest National Laboratory, U.S. and Canadian universities, a group in the UK, and NISER in India.
“I’m looking forward to building a new experiment — that’s always fun,” Bauer said. “Seeing dark matter particles for the first time would be fantastic.”