Leslie Thornhill, in the West workshop, in charge of beautifully polished Cherenkov mirrors

The finishing touches being given in the West Workshop to a mirror made from plexiglass . The mirror is part of a large area Cerenkov counter assembly to be used in an experiment, being carried out by a CERN-Munich group, to investigate the electromagnetic decay of particle resonances. The Cerenkov counter makes use of the fact that the passage of a charged particle through a transparent material at a velocity greater than the velocity of light in the material sets up a 'bow-wave' of light at an angle to the direction of the particle. The detection of this light selects particles moving with velocities in excess of some fixed threshold.
Pictured is Leslie Thornhill, in charge of the plastic scintillator workshop.