Cold White Matter, Cold Dark Matter

Today, London had its heaviest snowfall in years and years, though by the time I walked across Kensington Gardens, it was more slush than snow. Still, it was very pretty!


Prof Tim Sumner came downstairs from the Astrophysics group to give a seminar about the ZEPLIN III experiment, which was built on the 10th floor here, and recently transported to the Boulby Mine in Yorkshire.

It is a liquid and gaseous Xenon detector read out with photomultiplier tubes, and uses the ratio of two light signals, from scintillation and ionisation in liquid Xenon, to look for events with a signature that is characteristic of WIMPs (weakly interacting massive particles), a candidate for dark matter. It will soon start taking data, and will be probing the regions where Supersymmetric theories start predicting the existence of dark matter.

Personally, it was interesting to see the design and construction choices for their detector, having previously been in the group at Stanford building EXO, a liquid Xenon experiment looking for double beta-decay. The physics is completely different, galactic dark matter versus the nature of neutrino mass, but many of the challenges are quite similar.

Imperial Experimental Astrophysics Page