Fall 2011

DM Ice

DM Ice is a new experiment, led by Reina Maruyama, which is looking for dark matter using the IceCube neutrino detector.  Two prototypes were made at PSL and shipped out to the South Pole on November 5, 2010.  The photo to the right was taken during  deployment of one of the prototypes.  Reina on the collaboration with PSL and the experiment:

“Although the concept of the experiment has been around for a few years, the design and construction started in earnest in March 2010, and the bulk of the machining and assembly occurred over only two months, during  September - November of 2010.  We constructed two detectors as prototypes; each detector consists of a sodium-iodide scintillating crystal, two photo-multiplier tubes, and two IceCube mainboards housed in a stainless steel pressure vessel.

These detectors were deployed during the 2010/2011 construction season, 2500 m below the surface at the bottom of two separate IceCube strings.  Once deployed, they will remain frozen forever in the Antarctic ice.

“The full-scale experiment consists of 250 kg of sodium-iodide scintillating crystals buried in the Antarctic ice.  They will look for blips of light generated by dark matter particles as they interact with the detector material.  It is expected that dark matter forms a halo in and around our Galaxy, the Milky Way.  As the Sun orbits around the center of the Galaxy, it moves through the dark matter halo.  We are looking for the annual modulation in the amount of dark matter that our detector goes through as the velocity of the Earth (where our detector is located) and the Sun adds or subtracts with respect to the galactic center depending on the time of the year.

“These new detectors take advantage of the experience and expertise available at PSL in many ways.  The pressure vessel is based on the IceCube drill-head design.  It was pressurized up to 6000 psi in the test vessel at PSL.  The detectors use many of the concepts and knowledge developed for IceCube to construct and operate detectors in the harsh Antarctic environment.  It would not have been possible to construct these detectors in such a short amount of time without the expertise available at PSL. 

“Thank you, PSL, for making this happen!  And be on the look-out for the full-size detector in the next few years!”

-Reina Maruyama, for the DM-Ice and IceCube collaborations.


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