  Collimator wakefields in the Beam Delivery System (BDS) of future linear
colliders, such as the International Linear Collider (ILC) and the Compact
Linear Collider (CLIC), can be an important source of emittance growth and beam
jitter amplification, consequently degrading the luminosity. Therefore, a
better understanding of collimator wakefield effects is essential to optimise
the collimation systems of future linear colliders in order to minimise
wakefield effects. In the past, measurements of single-bunch collimator
wakefields have been carried out at SLAC with the aim of benchmarking theory,
numerical calculations and experiments. Those studies revealed some
discrepancies between the measurements and the theoretical models. New
experimental tests using available beam test facilities, such as the End
Station A Test Beam (ESTB) at SLAC, would help to improve our understanding on
collimator wakefields. ESTB will provide the perfect test bed to investigate
collimator wakefields for different bunch length conditions, relevant for both
ILC (300 micrometers nominal bunch length) and CLIC (44 micrometers nominal
bunch length) studies. Here we propose to perform new experimental tests of
collimator wakefield effects on electron/positron beams at SLAC ESTB.
