XENON Dark Matter

XENON is a new experiment to look for dark matter particles in the halo of our galaxy. It will operate a 1 tonne dual-phase time projection chamber (TPC) filled with liquid xenon in the Gran Sasso Underground Laboratory in Italy, which provides sufficient shielding for interactions caused by cosmic rays.

The UF group of Prof. Baudis is building a 3 kg liquid Xe, dual-phase TPC prototype to test different light and charge read-out systems and to calibrate the detector for dark matter particle interactions by using a neutron beam produced at the UF tandem accelerator.

The machine shop (Bill Malphurs) has built the vacuum cryostat system, which will allow to cool the experiment to 160 K by using the cooling power of liquid nitrogen. The system is made of three concentric cans, the outer UHV can, the radiation can made of aluminum, and the inner stainless steel Xe chamber, which is electropolished for purity reasons. A gold plated copper cold finger is attached to the radiation can, making the contact to the liquid nitrogen bath. Bill is also building the inner xenon detector, a structure made of polytetrafluoroethylene housing the active liquid volume and three wire grids defining the proportional scintillation region. An array of 4 square metal channel photomultipliers, with Rb-Cs-Sb photocathodes, able to detect the xenon scintillation light at 178 nm, will be located above the upper wire grid and detect both the primary and secondary scintillation light after a particle interacts in the xenon target.