Dr. Randy Johnson
Professor of Physics, Emeritus
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A.B., Princeton University, 1969Ph.D., University of California, Berkeley, 1975 |
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A.B., Princeton University, 1969Ph.D., University of California, Berkeley, 1975 |
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Email Address:
Randy.Johnson@uc.edu
Telephone: 513-556-0528
Fax: 513-556-3425
Mailing address (also UPS address):
Physics Department, ML 11
Room 417, Geology/Physics Building
University of Cincinnati
Cincinnati, OH 45221
MicroBooNE is an experiment designed to further investigate the LSND anomoly and the MiniBooNE low energy excess. The detector is a liquid argon time projection chamber about the size of a school bus. Like MiniBooNE, it is located in the Booster Neutrino Beam at Fermilab. The high position resolution and the good energy resolution of the time projection chamber should be able to do a good job of distinguishing photons coming from a neutrino interaction from charged current electrons. MiniBooNE, being basically a Cherenkov detector, could not make that differentiation and left open the questions as to whether the low energy "electron like" events were really electrons or photons. MicroBooNE should be able to tell.
MicroBooNE is also an R&D project for Fermilab as it develops its experience in building liquid argon time projection chambers.
LArIAT (Liquid Argon In A Testbeam) places the Argoneut time projection chamber in a low energy testbeam in the Meson Building (actually in a tunnel behind the Meson Building) at Fermilab. Its purpose is to measure interaction rates of various hadrons in liquid argon and to meausre the energy deposition profile of electron and muons in that medium.
Personal History
I came to neutrino experiments by a round-about route. I did my Ph.D.
thesis on hadronic interactions, an experiment performed at Fermilab just
after it opened, and continued those studies when I worked at Brookhaven
National Laboratory. I came to Cincinnati in 1984 and began working on
the SLD experiment at SLAC. The group at Cincinnati built and installed
the drift volumes for the endcap Cerenkov Ring Imaging Detectors in that
experiment.
I then joined the NuTeV collaboration which was designed to measure θw to higher precision than previous beamline neutrino experiments. The experiment used the Pascos-Wolfenstein relationship to cancel out the effects of the charmed quark mass to the determination. The experiment succeed but the difference between the measurements of neutrino experiments and the collider W/Z mass remained.
MiniBooNE followed NuTeV. It was an experiment that was designed to confirm or refute the LSND indication of a sterile neutrino. It was an experiment based on a large spherical container filled with mineral oil and phototubes. It neither confirmed nor refuted the LSND result. Instead, it showed an excess of low energy electron like neutrino events over what was predicted. If that excess were interpreted as neutrino oscillations in a two neutrino framework, consistent with the LSND result.
In 2005, I went to Germantown where I was a DOE grant monitor. I looked after a number of University groups and a couple of experiments (Daya Bay, and a number of non-accelerator experiments). My wife and I enjoyed our time in DC exploring the east coast on our free time. In 2008, I came back to Cincinnati and joined the Daya Bay experiment just as it was starting construction. That experiment now has the best measurement of the neutrino oscillation parameter, θ13 along with a number of other important measurement. US support of this experiment is now ending as I write this.
Even though retired (I retired in September, 2014, after working at the University of Cincinnati for 30 years), I am still collaborating on three neutrino experiment listed above. Retirment for me means no more faculty meeting, no grading of paper, and more time to travel. However, it does not mean an end to my physics career.
