Cryogenic Dark Matter Search (CDMS)

Observations of galaxies, galaxy clusters, distant supernovae, and the cosmic microwave background radiation tell us that ~85% of the matter in the universe is comprised of one or more species of dark matter.  With the continuing success of the Standard Model of particle physics, the existence of dark matter provides one of the few tangible sign posts as we seek to understand what lies beyond the Standard Model.  Deciphering the nature of this dark matter would be of fundamental importance to cosmology, astrophysics, and high-energy particle physics.

A leading hypothesis is that dark matter is comprised of particles that were produced moments after the Big Bang.  The Cryogenic Dark Matter Search (CDMS) is one of several experiments underway to directly detect these particles and begin an era of dark matter science that will hopefully allow us to understand the nature of the dark matter.

http://kipac.stanford.edu/kipac/sites/default/files/images/project-images/DM.png

The CDMS experiment has pioneered the use of cryogenic silicon and germanium detectors to perform sensitive searches for dark matter.  The recoiling nucleus from a dark matter interaction produces crystal lattice vibrations (phonons) and also electron-hole pairs (left).  The phonon and charge signals are captured by electrodes applied to the face of the crystal using photolithography (right).  These detectors provide unique capabilities for background rejection and offer unmatched sensitivity for the very small energy deposits associated with low-mass dark matter interactions.

 

The SLAC CDMS group participates in the operation and data analysis for the SuperCDMS Soudan experiment installed in the Soudan Underground Laboratory.  The experiment resides in a former iron mine in northern Minnesota at 2340’ below ground to shield the experiment from cosmic ray backgrounds.  Detector towers are installed into a cryostat that allows them to be cooled to 0.05 degrees Kelvin above absolute zero in order to detect the phonon signal (left).  The SuperCDMS Soudan experiment is currently running with five towers (15 detectors) providing a target mass of 9 kg of germanium (right).  Results from the experiment are the most sensitive to date for dark matter masses below 6 GeV.

 

The SLAC CDMS group is deeply engaged in the proposed SuperCDMS SNOLAB experiment to be located 6800’ below ground at the SNOLAB underground science laboratory near Sudbury, Canada.  SuperCDMS SNOLAB utilizes larger detectors in a versatile cryostat with an initial payload of 100 kg of germanium and 10 kg of silicon detectors (left).  The SLAC group has overall responsibility for the detector payload (detectors and associated cryogenic mechanics and electronics) and offline computing for the experiment.  SuperCDMS SNOLAB is one of the proposed “Generation 2” dark matter experiments that seek to push the sensitivity for observing dark matter to the “neutrino floor” where neutrino backgrounds begin to contribute (right).  SuperCDMS SNOLAB is also expected to make the first measurement of coherent neutrino scattering of the 8B neutrinos from the sun.

 

CDMS is a department of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University and the Particle Physics and Astrophysics Directorate at SLAC National Accelerator Laboratory.

SLAC CDMS Scientific Personnel:  Makoto Asai, Anders Borgland, Paul Brink, Gary Godfrey, Mike Kelsey, Chris Kenney, Richard Partridge, Kristi Schneck, Dennis Wright

SLAC CDMS Technical Personnel: Anirban Chatterjee, Matt Cherry, Ken Fouts, Jasmine Hasi, David Nelson, Marco Oriunno, Mike Racine, Matt Swift, Astrid Tomada

For further information regarding the SLAC CDMS group, please contact Richard Partridge.

Useful Links

 

CDMS Web Site (this is where to find out more about the CDMS experiment, including the latest news and results)

Soudan Underground Laboratory Site

SNOLAB Underground Science Laboratory Site

WIMP Dark Matter Direct Detection (Snowmass CF1 summary)

CDMS Internal Pages (password protected)

Information for new CDMS Collaborators

Job Postings

 

Postdoctoral Research Associate in the SLAC CDMS group – accepting applications until June 1, 2014