A monitor for gamma radiation at zero degrees from the SLC collision point

Abstract

deflections which occur at the collision point also emit softer gamma rays, called beamstrahlung. A device to detect these gammas is described. It has a converter to produce electron-positron pairs and a gas Cherenkov volume to detect them in the presence of a large, low energy, radiation background. The system is used for beam diagnostics at the SLC.

An automated focal point positioning and emittance measurement procedure for the interaction point of the SLC

“…When the beam intercepts the wire, both secondary emission and bremsstrahlung are produced with an intensity proportional to the number of beam particles striking the wire. The flux of bremsstrahlung is measured in a threshold cerenkov detector located behind the first main bending magnet downstream of the IP [7]. Th e wires are approximately 2, 3.5 and 15 pm in radius, which allows us to accurately measure a range of RMS beam sizes from 2 pm to 100 pm.…”