Research Interests

Co-Spokesperson for CDMS(Cryogenic Dark Matter Search) experiment which seeks to identify the dominant form of matter in and around our galaxy, under the hypothesis that it is made up of weakly interacting massive particles called WIMPs. The dark matter is seen through its gravitational interactions and neither absorbs nor emits light. It must be made of different matter from the atoms with which we are most familiar. We are operating a cryogenic facility one-half mile underground in the Soudan mine in northern MInnesota. At this location, we can shield ourselves from cosmic radiation and search for rare events, less than one per kg of detector per day, that would be produced by WIMPs. Over the past two years, our results see no candidate events and set limits that are a factor of 10 better than any other experiment in the world. The region that we are now exploring is very well motivated from elementary particle theories, where the favorite extension to the Standard Model, supersymmetry, proposes the existence of neutral particles that only interact via the weak interactions. The discovery of WIMPs and thus supersymmetry would simultaneously solve the most important problems in elementary particle physics and cosmology.

The detectors for CDMS are designed and fabricated at Stanford by our research staff and students. These detectors are operated at a temperature below 50 mK using dilution refrigerators, and take advantage of superconducting low noise amplifiers to read out the signals from elementary particle interactions. We are continuing to improve these detector technologies and have expanded their use for other instruments for astrophysics research. These include optical spectrophotometers, which time-stamp and energy-resolve each photon from the near infrared to the near ultra-violet. The optical TES (superconducting Transition Edge Sensor) instrument has been used to observe the Crab pulsar and provide unique information on the spectral changes as a function of Crab rotation phase. In addition, the same instrument technologies are being developed for the next generation of x-ray spectrometers to observe the solar corona and the warm-hot intergalactic media.

Specialty: Low temperature particle detectors 

Career History

• B.S., 1968, University of Virginia 
• Ph.D., 1975, Stanford University 
• Research Associate, Stanford University, 1975-79 
• Senior Research Associate, Stanford University, 1979-80 
• Acting Assistant Professor, Physics Department, Stanford University, 1980-81 
• Assistant Professor, Stanford University, 1981-84 
• Associate Professor, Stanford University, 1984-91 
• Professor, Stanford University, 1991-present 
• Stanford Dean's Award for Distinguished Teaching, 1990 
• Fellow of the American Physical Society, 1996 

Research Associate

• Paul Brink

Postdoctoral Researcher

• Jodi Cooley-Sekula

Research Assistant

• Astrid Tomada
• Larry Novak
• Mike Hennessey
• Jim Perales

Graduate Students 

• Joelle Barral
• Thomas J. Bay
• Jennifer Burney
• Steve Leman
• Walter Ogburn
• Matt Pyle