Research & Scholarship
Muon capture on the proton and deuteron: The MuCap experiment at the Paul Scherrer Institute near Zurich, Switzerland) measures the proton's weak pseudoscalar coupling¨ g through the muon capture rate in pure hydrogen, providing a precision test of chiral perturbation theory. I implemented the data acquisition and online analysis systems, designing high-speed waveform digitizer electronics. We are now measuring the rate of muon capture in deuterium, which will constrain two-nucleon physics (including proton-proton fusion). For this measurement, I am working with students at Regis to develop Monte Carlo simulations and to design a low-noise preamplier that will work at cryogenic temperatures.
Muon anomalous magnetic moment: The muon (g 2) experiment at Brookhaven National Laboratory has measured the anomalous magnetic moments of positive and negative muons. A discrepancy of 3.4 standard deviations between the experimental measurement and the theoretical calculation is still unresolved, possibly hinting at subatomic physics beyond the Standard Model. My Ph.D. thesis is based on this experiment, and we are currently preparing to relocate it to Fermilab to improve the precision by a factor of 4. I am responsible for the scintillating ber harp beam monitors that will sample the beam distribution at two positions in the muon storage ring.
Waveform digitizer and neutron detector technology: I have developed and continue to support and upgrade a set of 12-bit, 250 million sample per second waveform digitizers that are used to develop techniques to search for concealed nuclear material by a group at Los Alamos National Laboratory. We also employ them in experiments to develop neutron detectors for nuclear energy experiments at the Colorado School of Mines.
Publications in Peer-Reviewed Journals
N.P.M. Brantjes et al., Correcting systematic errors in high-sensitivity deuteron polarization measure-
ments, Nucl. Instrum. Meth.A66449 (2012).
F.E. Gray, C. Ruybal, J. Totushek, D.-M. Mei, K. Thomas, and C. Zhang, Cosmic Ray Muon Flux at the Sanford Underground Laboratory at Homestake, Nucl. Instrum. Meth.A63863 (2011). [arXiv:1007.1921]
D.M. Webber et al. [MuLan Collaboration], Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant to Part-per-Million Precision, Phys. Rev. Lett. 106041803 (2011). [arXiv:arXiv:1010.0991]
D.-M. Mei, C. Zhang, K. Thomas, and F. Gray, Early Results on Radioactive Background Characterization for Sanford Laboratory and DUSEL Experiments, Astropart. Phys.3433 (2010). [arXiv:0912.0211]
S. Abe et al. [KamLAND Collaboration], Production of Radioactive Isotopes through Cosmic Muon Spallation in KamLAND, Phys. Rev.C81025807 (2010). [arXiv:0907.0066]