The status of stochastic cooling

Abstract

Presented at a symposium to celebrate the 30th anniversary of electron cooling, this report is intended to give the status of the companion technique, stochastic cooling, some 28 years after its invention. An overview of past developments reveals the close relationship between the two cooling ideas. Then the report concentrates on the principal ingredients of stochastic cooling in order to discuss the limits encountered and some recent ideas for pushing back these limits.

History of stochastic beam cooling and its application in many different projects

“…Turning to the mixing discussed at length in [7], we note that stochastic cooling only works if after each correction the samples (at least partly) re-randomises (desired mixing), and at the same time a particle on its way from pick-up to kicker does not slip too much with respect to its own signal (undesired mixing). The mixing rates 1/M and 1/M are related to the fraction of the sample length by which a particle with the typical momentum deviation slips with respect to the nominal particle.…”

“…The price to pay is a slower cooling rate, than with M = 1 andM 1. 'Optimum mixing lattices' (also referred to as 'split ring designs') have been proposed [7,8]. However, up to now they have not been used.…”