Mark C. Chen, Ph.D. (Caltech), P.Eng.

    Gordon and Patricia Gray Chair in Particle Astrophysics
    CIFAR Senior Fellow
        Department of Physics, Engineering Physics & Astronomy
        Queen's University

Stirling Hall 208E

(613) 533-6861

mchen at
Mark in the Universal Interface prior to
                    installation Mark holding fluorescence cuvette


Research Interests


Neutrino Physics

Discoveries of neutrino mass and mixing between 1998-2002 yielded the first hints of physics beyond the Standard Model (of particles and interactions). The Sudbury Neutrino Observatory (SNO) discovered that solar neutrinos undergo flavour oscillations (electron neutrinos transform into mu and/or tau neutrinos) en route from the Sun to the Earth. The SNO experiment stopped taking data in Nov 2006 and final data analysis and results were published in 2013.

The study of the phenomenon of neutrino oscillations with improved precision continues. SNO+ was proposed as a follow-up experiment to SNO and is now under construction (nearing completion). By replacing the heavy water in SNO with liquid scintillator, the SNO+ detector will be sensitive to lower energy neutrinos. This will enable precision studies of neutrino physics, sensitive to new particle physics connected to the neutrino-matter interaction, including non-standard neutrino couplings and mass-varying neutrinos. The low energy pep solar neutrinos allow neutrino oscillations with solar neutrinos to be explored with higher precision. The CNO solar neutrinos could be detected for the first time, addressing questions related to metallicity in the solar core (solar chemical abundances). SNO+ would also be a good detector for geo neutrinos, the neutrinos emitted by natural radioactivity in the Earth. By measuring the flux of geo neutrinos, SNO+ would address fundamental questions related to the quantity of radiogenic heat in the deep Earth and composition models of the continental crust, as well as whole-Earth composition models.

In SNO+ we also plan to mix over 2 tonnes of tellurium into the liquid scintillator. This would enable a search for neutrinoless double beta decay of the isotope Te-130. The observation of neutrinoless double beta decay would determine if neutrinos are their own antiparticles or not, and would probe the absolute scale of neutrino mass. The determination of the Majorana/Dirac nature of neutrinos is one of the most critical questions that must be answered in order to understand and incorporate massive neutrinos into new particle theories at the Grand Unification energy scale.

Particle Astrophysics

My other research interests include:
- geo neutrinos: studying the neutrinos emitted by natural radioactivity in the Earth as a way to probe the composition of the Earth's interior
- developing low-background environments for WIMP dark matter detectors
- studying ultra-high energy cosmic rays and neutrinos via detection of Cherenkov radio emission
- understanding the physics and detection of supernova neutrinos
- developing novel scintillators for future experiments


PHYS 225 - Mechanics

PHYS 250 - Foundations of Experimental Physics

PHYS 352 - Measurement, Instrumentation and Experiment Design

PHYS 450 - Advanced Physics Laboratory
PHYS 832 - Classical Electrodynamics

PHYS 841 - Experimental Methods for Particle Astrophysics

PHYS 843 - High Energy Astroparticle Physics

PHYS 844 – Neutrino Physics and Astrophysics

Select Publications

  • Chen M.C. (2014) Geoneutrino Detection. In: Holland H.D. and Turekian K.K. (eds.) Treatise on Geochemistry, Second Edition, vol. 15, pp. 443-453. Oxford: Elsevier.
  • B. Aharmim et al., (SNO Collaboration), Combined Analysis of all Three Phases of Solar Neutrino Data from the Sudbury Neutrino Observatory, Phys. Rev. C 88, 025501 (2013).
  • H.M. O’Keeffe, E. O’Sullivan and M.C. Chen, Scintillation Decay Time and Pulse Shape Discrimination in Oxygenated and Deoxygenated Solutions of Linear Alkylbenzene for the SNO+ Experiment, Nucl. Instrum. Meth. A 640, 119 (2011).
  • B. Aharmim et al., (SNO Collaboration), Low-Energy-Threshold Analysis of the Phase I and Phase II Data Sets of the Sudbury Neutrino Observatory, Phys. Rev. C 81, 055504 (2010).
  • C. Arpesella et al., (Borexino Collaboration), “Direct Measurement of the 7Be Solar Neutrino Flux with 192 Days of Borexino Data”, Phys. Rev. Lett. 101 091302 (2008).
  • S.N. Ahmed et al. (SNO Collaboration), Measurement of the Total Active 8B Solar Neutrino Flux at the Sudbury Neutrino Observatory with Enhanced Neutral Current Sensitivity, Phys. Rev. Lett. 92 181301 (2004).
  • Q.R. Ahmad et al. (SNO Collaboration), Direct Evidence for Neutrino Flavor Transformation from Neutral-Current Interactions in the Sudbury Neutrino Observatory, Phys. Rev. Lett. 89 011301 (2002).
  • Q.R. Ahmad et al. (SNO Collaboration), Measurement of Day and Night Neutrino Energy Spectra at SNO and Constraints on Neutrino Mixing Parameters, Phys. Rev. Lett. 89 011302 (2002).
  • L. Cadonati, F.P. Calaprice and M.C. Chen, Supernova Neutrino Detection in Borexino, Astropart. Phys. 16 361 (2002).
  • G. Alimonti et al. (Borexino Collaboration), Science and Technology of Borexino: A Real-Time Detector for Low Energy Solar Neutrinos, Astropart. Phys. 16 205 (2002).
  • Q.R. Ahmad et al. (SNO Collaboration), Measurement of the Rate of nue + d  to  p + p + e- Interactions Produced by 8B Solar Neutrinos in the Sudbury Neutrino Observatory, Phys. Rev. Lett. 87 071301 (2001).
  • M. Chen et al., Quenching of Undesired Fluorescence in a Liquid Scintillator Particle Detector, Nucl. Instrum. Meth. A 420 189 (1999).
  • C.G. Rothschild, M.C. Chen and F.P. Calaprice, Antineutrino Geophysics with Liquid Scintillator Detectors, Geophys. Res. Lett. 25 103 (1998).
  • G. Alimonti et al., (Borexino-CTF Collaboration), Measurement of the 14C Abundance in a Low-Background Liquid Scintillator, Phys. Lett. B 422 349 (1998).

Popular Science Press and Communications

CBC Radio "The World this Weekend" - June 2012
Maclean's - November 2011
UK Channel 4 "Brave New World with Stephen Hawking" - October 2011
Radio Canada - January 2009
ideaCity08 - June 2008
APS NeutrinoFest - April 2005
McGraw-Hill Encyclopedia of Science and Technology, 2003 Yearbook entry on Neutrino Mass and Oscillations
BBC Radio "Science in Action" - February 1998
The Economist - February 1998
Science News - January 1998

Last Revised: July 22, 2014