SNO+ is a multi-purpose low energy neutrino experiment, currently under construction in SNOLAB in Sudbury, Canada. The experiment inherits the successful Sudbury Neutrino Observatory (SNO) detector, with the original heavy water target replaced with liquid scintillator. This allows the detection of much lower energy neutrinos and opens the door to a rich neutrino physics programme. The Queen Mary SNO+ group is involved in many areas of the experiment specialising in software, analysis and development of optical and radioactive calibrations.
The main goals of SNO+ are to:
- Search for neutrino-less double beta decay. This process is a golden-channel to test whether the neutrino is a Majorana particle that can essentially act as its own antiparticle. If observed it would also tell us about the absolute neutrino mass scale. SNO+ will deploy a large quantity of Tellurium 130 in the scintillator volume to perform this measurement.
- Measure the low energy components of the solar neutrino energy spectrum. In particular, measure the flux of neutrinos produced by the pep interaction in the Sun. No other experiment can observe this signal due to C11 background events, but these aren't a problem in SNO+, which is well shielded from this background due to its location 2km underground in the Vale Creighton Nickel mine. Accurately measuring the pep flux will allow us to test neutrino oscillation models and search for new physics processes.
- We can also measure anti-neutrinos from nearby nuclear reactors and geoneutrinos produced by radioactive decays in the Earth's crust and mantle. We will also be able to detector neutrinos from supernovae if one occurs nearby during the course of the experiment.
A large proportion of the QM SNO+ research is supported through an ERC grant for the neutrinoSNO+ project.
At Queen Mary, we are involved in a number of critical aspects of the experiment, with leadership roles in Analysis, Monte Carlo, Verification, Reconstructino and Data Quality, as well as day-to-day activities to prepare the detector for first data. As data collecting starts we will also become more heavily involved in the experiments physics analysis programs.
- We have developed analysis to understand and reject event pile-up where two events within the same trigger window could mimic a true double beta signal event. The tools developed reduce this possibly dangerous background to negligible levels.
- We are working on analyses to measure internal background contributions from radioactive isotopes within the scintillator volume. The tools allow to characterise and reject these backgrounds and also use their properties to help calibrate the detector.
- We are making significant contributions to the calibration program for the experiment, developing a beta emitting calibration source to directly verify the scintillator response to betas and an analysis to extract the optical scattering parameters of the liquid scintillator.
- We take a leading role in the development, verification and maintenance of the complex Monte Carlo modelling and analysis software.
- We lead Data Processing efforts using GridPP resources.
- We lead the Reconstruction Working Group, developing algorithms to reconstruct the position and energy of events from PMT hit timing information.
- We lead the Data Quality working group, developing tools to ensure the quality of data collected for physics analyses.
Students hard at work preparing the lab and detector at SNOLAB.
For members of the QMUL SNO+ group click here
If you are interested in applying for a post-doctoral fellowship position, in particular through the EC Marie Curie actions (incoming or intra-european) or other sources, please contact Dr Jeanne Wilson as there are exciting possibilities to extend the research of the group and we would be happy to work with you to develop a competitive funding application.
Information on PhD places within the PPRC group can be found here. Successful candidates could choose to work on SNO+ and will then have the opportunity to participate in many aspects of the experiment, including some on-site calibration and shift work, and will receive both specific and general training in particle physics.
It may also be possible to obtain summer student placements to work on SNO+ projects. For details of placements see here.
If you are interested in PhD work on SNO+ please contact Dr Jeanne Wilson.
Papers and Talks
- Double Beta Decay, summary of UK programme at STFC PPAP Community Meeting, Imperial, September 2015
- Seminar on SNO+ presented at the University of Heidelberg, February 2015
- The SNO+ Experiment, Talk at NNN 2014, Paris
- SNO+, talk at IPA 2014 meeting, QMUL
- Current Status and Future Prospects of SNO+, published in special issue "Neutrino Masses and Oscillations" of Advances in High Energy Physics (Hindawi)
- The Calibration System for the Photomultiplier array of the SNO+ experiment, published 2014
- An Experimental Review of Solar Neutrinos, proceedings NuPhys 2014