University of Minnesota
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Keith Ruddick

ruddick @ • curriculum vitae


I grew up and was educated in England and came to the US in 1964 as a postdoc at the University of Michigan. In 1966, I came to Minnesota as an Assistant Professor to see what a real winter is like and have been here ever since. I introduced the use of counter/electronic techniques to the fledgling Experimental High Energy Physics group and we did a series of experiments at the Zero Gradient Synchrotron (ZGS) at Argonne National Laboratory until it closed in 1980; I was chairman of the ZGS Users Organization for the last few years of its life. We moved to Fermilab and, in collaboration with a Rochester University group, carried out an elegant experiment to make the definitive measurement of meson electromagnetic decays using the Primakoff effect – this was a powerful test of the quark model of elementary particles. In 1980, we built and installed the 40 ton Soudan 1 detector in the Soudan mine in northern Minnesota to look for proton decay, followed later by the much larger1 kton Soudan 2 detector. Neither of these saw proton decay, but the latter did give clear evidence for oscillations of atmospheric neutrinos - the basis of our research ever since. Some of my graduate students also carried out cosmic ray studies using detectors on the surface in coincidence with both Soudan 1 and 2, and all have gone on to successful academic careers. To study neutrino oscillations under “controlled” conditions, several groups proposed the construction of a neutrino beam at Fermilab and aimed at a Soudan detector. This culminated in the large MINOS experiment that is currently producing precise measurements of neutrino oscillation parameters. I led the design of a possible liquid scintillator detector for MINOS, which was rejected in favor of the actual solid scintillator design, but which now forms the basis of the 15-20 kton NOvA liquid scintillator detector to search for a rarer neutrino oscillation mode, not well resolved in the MINOS detectors. I retired in 2007 but maintain an active interest in the MINOS and NoVA experiments.

Summary of Interests
High energy particle interactions; nucleon decay; neutrino interactions; high energy cosmic rays; detector development.

About My Work

Neutrino oscillations; nucleon decay; elemental composition of the cosmic rays; detector development.

The following links give details on the NOvA and MINOS experiments, and also on the Soudan Underground Laboratory:

Selected Publications

MINOS Collaboration, A study of muon neutrino disappearance using the Fermilab main injector neutrino beam, submitted to Physical Review

Soudan 2 Collaboration, Measurement of the L/E distributions of atmospheric neutrinos in Soudan 2 and their interpretation as neutrino oscillations, Phys. Rev. D68:113004 (2003)

P. Border et al., A large liquid scintillator detector for a long baseline neutrino experiment, Nuc. Inst. Meth. A463, 194 (2001) [abstract]

K. Ruddick and K. Wick, An accurate measurement of g using falling balls, Am. J. Phys. 67. 962 (1999) [abstract]

K. Ruddick, Model for underground muons associated with Cygnus X-3, Phys. Rev. Lett. 57, 531 (1986) [abstract]

T. Jensen et al., Radiative decay width of the rho meson, Phys. Rev. 27, 26 (1983) [abstract]

R. C. Chase et al., pi-minus proton charge exchange at high momentum transfer, Phys. Rev. Lett. 22, 1137 (1969) [abstract]


B.Sc., Birmingham University, England, 1961.
Ph.D., Birmingham University, England, 1964.