New Beginnings for SNO+ Detector

Thursday, October 25, 2018

The Nobel-Prize winning Sudbury Neutrino Observatory (SNO) is starting a new chapter in its life. After years of preparation and technical developments, liquid scintillator has started to flow into the SNO+ detector.  

The 12-m diameter acrylic vessel, located deep underground in a Canadian nickel mine, previously housed heavy water on loan from the Canadian government.  The SNO experiment was critical in resolving the so-called solar neutrino problem, thus demonstrating neutrino flavor change, and providing evidence for non-zero neutrino mass. The legacy data set from SNO still offers unique insights into neutrino properties and also into backgrounds for future experiments due to SNO’s deep location and unique detection capabilities. Analysis of this data is being led by Prof. Gabriel Orebi Gann and her group at UC Berkeley / LBNL.

The soon-to-be scintillator-filled vessel will have sensitivity to a much lower range of energies, opening up new physics reach - including the first North America based detection of antineutrinos produced in the earth’s crust. These geoneutrinos can shed light on heat production beneath the surface of the earth. SNO+ will also measure the spectrum of low energy solar neutrinos, with sensitivity to new physics effects such as so-called sterile neutrinos, and seek to resolve uncertainties in the metal content of the Sun by a measurement of neutrinos from the CNO fusion cycle.

The primary goal of SNO+ is a search for neutrinoless double beta decay, a rare process possible only if neutrinos are their own antiparticle, or Majorana in nature. SNO+ will load the scintillator with 0.5% by mass of tellurium in summer 2019.  World-leading sensitivity is anticipated for a search on this isotope.

The start of the scintillator fill process heralds a new beginning for this experiment. Prof. Orebi Gann’s group at UC Berkeley / LBNL is leading analysis effort of data from the preliminary water phase, and preparations for fast turnaround of early scintillator data.