Dr. Trevor J. Stocki

Office Location:
Radiation Protection Bureau - Health Canada
775 Brookfield Road, AL 6302D, Ottawa, ON, K1A 0K9

Dr. Trevor J. Stocki received a B.Sc. in honours physics from the University of Alberta in 1991 with research experience in weak interaction physics.  The project was the construction of an ultra low noise ionization chamber, used in a TRIUMF experiment on parity non-conservation between two protons at 222 MeV.   Trevor continued to study weak interactions while working towards his Ph.D. at the University of British Columbia. His thesis topic involved the measurement muon capture rates and muonic hyperfine transition rates.  During his Ph.D., Trevor was also involved in the investigation of unusual anthropogenic radionuclides measured at a Comprehensive nuclear-Test-Ban Treaty (CTBT) monitoring station. Dr. Stocki became a research associate at Simon Fraser University, where he was involved in laser trapping of radioactive atoms, to study weak interaction effects in the nucleus.  Presently, Dr. Stocki is a research scientist with Health Canada at the Radiation Protection Bureau, doing research on Environmental Radioactivity.  Recently he has become the leader of an IAEA (International Atomic Energy Agency) working group concerning controlled nuclear releases.

Research Interest

Trevor Stocki’s current line of research is working towards keeping the world safe through the use of subatomic physics techniques.  Dr. Stocki is a multidisciplinary physics researcher who is involved in the study of radioactivity in the environment through the use of: machine learning techniques, muonic physics, monte carlo techniques, and transfer pathways including atmospheric transport.

Dr. Stocki has also performed research on the use of Machine Learning (Artificial Intelligence) to determine whether radioxenon, measured at a CTBT monitoring station, was the result of an explosion or from another anthropogenic process.  The radioxenon is measured by the use of gamma ray spectroscopy and the discrimination is done by using Machine Learning algorithms.

Currently looking for a M.Sc. Student:

The project is to help develop a flash ADC for a HPGe detector for a muon project and to analyze data from that experiment.

Dr. Stocki is also using his past muon physics experience to develop techniques to find special materials.  He is currently performing research in the area of muonic x-rays and in the area of muonic cosmic rays for this purpose.

The M.Sc. project has to do with detecting muonic x-rays. When a negative muon stops in matter, it replaces an electron in that atom.  The muon orbit is between the nucleus and the rest of the electrons in, what has been termed, an exotic atom.   The muon’s initial orbit is in a highly excited state.  The muon then drops down these “muonic” energy levels giving off Auger electrons and characteristic x-rays.  The energies of these x-rays are unique to the element that the muon stopped in and can be measured using standard gamma ray spectroscopy techniques with a High Purity Ge detector.

Once at the muonic ground state, the muon can either decay in orbit or capture on a proton in the nucleus.  This second option would cause the proton to transform into a neutron and a neutrino, leaving the nucleus in a highly excited state.  The nucleus then de-excites by emission of neutrons and gamma rays.

Muons are the largest component of cosmic rays at the surface of the earth.  By using particle physics tracking techniques, one can perform muon tomography to detect materials of interest. Dr. Stocki is collaborating within the Canadian CRIPT team (Cosmic Ray Inspection and Passive Tomography). His research interest is in the use of computer algorithms to perform the detection of materials of interest.  Namely, machine learning techniques and/or computer vision techniques.

Selected publications:

1. Stocki Trevor J.,  Li Guichong,  Japkowicz Nathalie, Ungar R Kurt.  Machine Learning for compliance verificiation of the Comprehensive Nuclear-Test-Ban Treaty.   Journal of Environmental radioactivity 101, 68-74 (2010).
2. T.J. Stocki, L. Beaton, A. Tran, K. Bock, M-C Lo, R.K. Ungar Monte Carlo Simulations of Semi-infinite Clouds of Radioactive Noble Gases. Radioprotection 44, No. 5 735-740 (2009).
3. Stocki T.J., Ungar R.K., D’Amours R., Korpach, E., Malo, A., Bean, M., Hoffman, I. Jean, M. Heinrich P., and Armand P. Measurement and Modelling of radioxenon plumes in the Ottawa Valley.  J. Env. Radioactivity.  99, 1775-1788 (2008).
4. Saey, P.R.J., Bean, M., Becker, A., Coyne, J., d’Amour, R., De Geer, L.-E. Hogue, R., Stocki, T.J., Ungar, R.K., and Wotawa, G. A long distance measurement of radioxenon in Yellowknife, Canada, in late October 2006. Geophysical Research Letters 34, L20802 (2007).
5. Zhao X.-L. Soto, C. Kieser W.E., Litherland, A.E., Tracy, B.L., Ungar, K and T. Stocki. Measurement of 10Be in air filters using BeF- ions from BaBeF4. Nuclear Instruments and Methods B259 345-350 (2007).
6. T.J. Stocki, L. Beaton, A. Tran, K. Bock, R.K. Ungar, "Simulations of Semi-infinite Clouds of 133Xe." Nuclear Instruments & Methods A , A580 683–686. (2007).
7. D.F. Measday and T.J. Stocki, "Gamma-rays from muon capture in Al, and Si." Phys. Rev. C. 75 035504 (2007).
8. D.F. Measday, T.J. Stocki, and H. Tam, "Gamma-rays from muon capture in I, Au, and Bi." Phys. Rev. C. 75 045501 (2007).
9. P.R.J. Saey, G. Wotawa, L.-E. De Geer, A. Axelsson, M. Bean, R. D'Amours, K. Elmgren, J. Peterson, A. Ringbom, T.J. Stocki, R. K. Ungar, "Radioxenon background at high northern latitudes" Journal of Geophysical Research 111 D17306 (2006).
10. J.H.D.C. Clarke, D.S.A. Armstrong, T.P. Gorringe, M.D. Hasinoff, P.M. King, T.J. Stocki, S. Tripathi, D.H. Wright, P.A. Zolnierczuk. "Ortho-para transition rate in mu-molecular hydrogen." Phys. Rev. Lett. 96 073401, (2006).
11. David Measday and Trevor J. Stocki. "Gamma-rays from muon capture in natural Ca, Fe, and Ni" Phys. Rev. C ,73 045501 (2006).
12. T.P. Gorringe, D.P. Corbin, T.J. Stocki, "Recoil alignment in muon capture on nitrogen-14" Phys. Rev. C 71 035503, (2005).
13. T.J. Stocki, X. Blanchard, R.D. D'Amours, R.K. Ungar, J.P. Fontaine, M. Sohier, M. Bean, T. Taffary, J. Racine, B.L. Tracy, G. Brachet, M. Jean, D. Meyerhof, "Automated radioxenon monitoring for the comprehensive nuclear-test-ban treaty in two distinctive locations: Ottawa and Tahiti" Journal of Environmental Radioactivity 80 305-326, (2005).