The Pepperpot Measurement Bench

The 2009 USPAS (US Particle Accelerator School) included a one week session on Beam Instrumentation of which one day was dedicated to emittance measurements. In addition to formal lectures, a laboratory session, demonstrating different types of transverse emittance measurements, was prepared. The exercises consisted on measurements on an optical bench, where the particle beam is replaced by a light source and the electro-magnetic beam optics is replaced by light optics. These experiments were developed purely for educational purposes but they demonstrate many of the difficulties encountered on the equivalent measurements on the accelerator. Signals must be filtered using digital filters, profiles must be fitted to extract physically meaningful results etc.