Measurement of nanometer electron beam sizes with laser interference using Shintake Monitor

The Shintake Monitor is an essential beam tuning device installed at the interaction point (IP) of ATF2 [1], the final focus test beam line of the Accelerator Test Facility (ATF) to measure its nanometer order vertical e− beam sizes (σy⁎). The e− beam collides with a target of laser interference fringes, and σy⁎ is derived from the modulation depth of the resulting Compton signal photons measured by a downstream photon detector. By switching between several laser crossing angle modes, it is designed to accommodate a wide range of σy⁎ from 20nm to a few micrometers with better than 10% accuracy. Owing to this ingenious technique, Shintake Monitor11The Shintake Monitor, invented by Dr. T. Shintake, had first been put into practical usage at the FFTB experiment at SLAC [4].[2,3] is the only existing device capable of measuring σy⁎