Rasmus Ischebeck, Christopher Barnes, Franz-Josef Decker, Mark Hogan, Richard
Iverson, Patrick Krejcik, Caolionn O'Connell, Robert Siemann, Dieter Walz (SLAC,
Menlo Park, California), Ian Blumenfeld, Neil Allen Kirby (Stanford University,
Stanford, Califormia), Chris Clayton, Chengkun Huang, Devon K. Johnson, Wei
Lu, Kenneth Marsh (UCLA, Los Angeles, California), Suzhi Deng, Bing Feng, Erdem
Oz (USC, Los Angeles, California)
The accelerating field that can be obtained in a beam-driven plasma wakefield
accelerator depends on the current of the electron beam that excites the wake.
In the E-167 experiment, a peak current above 10\,kA will be delivered at a
particle energy of 28\,GeV. The bunch has a length of a few ten micrometers
and several methods are used to measure its longitudinal profile. Among these,
autocorrelation of coherent transition radiation (CTR) is employed. The beam
passes a thin metallic foil, where it emits transition radiation. For wavelengths
greater than the bunch length, this transition radiation is emitted coherently.
This amplifies the long-wavelength part of the spectrum. A scanning Michelson
interferometer is used to autocorrelate the CTR. However, this method requires
the contribution of many bunches to build an autocorrelation trace. The measurement
is influenced by the transmission characteristics of the vacuum window and beam
splitter. We present here an analysis of materials, as well as possible layouts
for a single shot CTR autocorrelator.