NEWS-SNO is the newest project of spherical gas detectors. The first of its kind, it will open a new window in the Dark Matter particle parameter space exploration.
Located in Sudbury, Canada, SNOLAB is the second deepest underground laboratory in the world. SNOLAB operates out of the active Vale Creighton Mine.
The very thick rock coverage (2000 m) allows to filter out the cosmic rays and their secondary particles while the low cross section particles like neutrinos or Dark Matter particles are able to cross the rock and reach the underground detector.
The main aims of the experiment will be to search for:
- Light Dark Matter particles with spin independent couplings, in the 0.1 – 5 GeV range; see below anticipated performances vs the current present experimental limits (Feb 2015)
- Kaluza Klein axions through their 2 photon decay
- Light Dark Matter particles with spin dependent couplings, through the use of H nuclei from Hydrogen rich gas such as CH4.
In the above figure, new calculated limits obtained for around 100 kg-days exposure with Ne/He/CH4 are shown, taking into account anticipated background from materials, a detector threshold set to 1 electron (i.e. 20 to 40 ev ee), and quenching factors extrapolated down to 100-200 eVNR.
ee: eV in electron equivelant energy
NR: eV in nuclear recoil equivelant energy
The sphere is made of copper and surrounded by two shields. The inner part of the Compact Lead shield is cast from archeological lead, and the outer part is made from low activity lead. Each piece of the lead shield has a stainless steel skin used as a support. The whole system is sitting in a high-density polyethylene (HDPE) shield to thermalize and capture the neutrons. One section of the HPDE wall and the support structure has been removed for clarity.