Study of cavity BPM for next generation linear accelerators such as CLIC and ILC
Presented by Nirav JOSHI
Cavity Beam Position Monitor (BPM) systems form an important part of the diagnostics for linear accelerators with low emittance beam. Using cavity BPMs, the position resolution of less than 100 nm has been demonstrated in single bunch mode operation. Next generation Linear collider, such as proposed Compact LInear Collider (CLIC) and International Linear Collider (ILC) will have high current and shorter bunch separation. Effects of the beam parameters on BPM design and signal processing techniques has been studied. The design, fabrication and testing of the cavity BPM has been studied in collaboration with the DIAMOND Light source UK. Different ideas, such as frequency separation and broad band coaxial adapter, has been studied and the results from simulation and testing of the prototype has been compared. Effects of the beam parameters on the cavity performance has been examined. Additional complexity in processing because of the signal overlap due to the comparatively shorter bunch spacing has been studied using the cavity BPM system on the Accelerator Test Facility (ATF2) at KEK, Japan. A signal processing method, based on a signal subtraction algorithm, has been developed and tested on the beam as well as simulated data. The limitations applied on the design of electronics has been discussed. The possible induced wake fields has been simulated for a proposed BPM design for the Clic Test Facility (CTF3). Results has been compared for simulation codes, such as ACE3P and GdfidL. A simple algorithm has been developed to calculate the collective wake fields from multiple bunches with different position offsets and charge. Depending on the observations, the limitations and advantages of the different techniques have been identified, and the design parameters for BPM system and processing technique for the CLIC has been accordingly suggested.
Location: Centro Nacional de Aceleradores - CNA
Address: Av. Tomas Alba Edison,7 // Parque Cientifico y Tecnologico Cartuja 93, 41092, Sevilla, Spain