Bunch Purity Measurements

Description

An Avalanche Photo Diode is used to measure the bunch purity of the SR beam. Two bunch purity measurement systems are installed in the machine: one on D4 and one on D19.

Diode: HAMAMATSU S5343SPL 10mm depletion layer.

Amplifier: Any well protected, large bandwidth (>1GHz) amplifier should be fine. But, we have had trouble with minicircuit LN___ amps dying in turn-on transients...
The amplifier power supply (12V) is given by the NIM rack.
Motorization: The diode is protected against the x-beam when not in used. The movement of the protection in the tunnel is control by a Paragon system.
High-Voltage: The High-Voltage power supply for the diode is a double-width NIM module. -150V is fine but it is very sensitive. Try (hard) not to exceed -158V!