Coherent bremsstrahlung at the B factories SLAC PEP-II and KEK Tristan-B.

Abstract

Coherent bremsstrahlung (CBS) is a specific type of radiation at colliders with short bunches. In the present paper we calculate the main characteristics of CBS for the planned projects of the {ital B} factories PEP-II and Tristan-B. At these colliders {ital dN}{sub {gamma}}{similar_to}(10{sup 7}--10{sup 8}) {ital dE}{sub {gamma}}/{ital E}{sub {gamma}} photons of CBS will be emitted for a single collision of the beams in the energy range {ital E}{sub {gamma}}{approx_lt}10 keV. It seems that CBS can be a potential tool for optimizing collisions and for measruing beam parameters. Indeed, the bunch length {sigma}{sub {ital z}} can be found from the CBS spectrum because the critical energy {ital E}{sub {ital c}}{proportional_to}1/{sigma}{sub {ital z}}; the horizontal transverse bunch size {sigma}{sub {ital x}} is related to {ital dN}{sub {gamma}}{proportional_to}1/{sigma}{sub {ital x}}{sup 2}. Besides, CBS may be very useful for a fast control over an impact parameter {ital R} between the colliding bunch axes because a dependence of {ital dN}{sub {gamma}} on {ital R} has a very specific behavior.