CERN Accelerating science

Article
Title	Experimental Progress in Fast Cooling in the ESR
Author(s)	Steck, Markus ; Beckert, Karl ; Beller, Peter ; Franzke, Bernhard ; Nolden, Fritz
Affiliation	(GSI, Darmstadt)
Publication	2005
In:	21st IEEE Particle Accelerator Conference, Knoxville, TN, USA, 16 - 20 May 2005, pp.615
Subject category	Accelerators and Storage Rings
Abstract	The ESR storage ring at GSI is operated with highly charged heavy ions. Due to the high electric charge the ions interact much stronger with electromagnetic fields. Therefore both cooling methods which are applied to stored ions in the ESR, stochastic cooling and electron cooling, are more powerful than for singly charged particles. The experimental results exhibit cooling times for stochastic cooling of a few seconds. For cold ion beams, electron cooling provides cooling times which are one to two orders of magnitude smaller. The beams are cooled to beam parameters which are limited by intrabeam scattering. At small ion numbers, however, intrabeam scattering is suppressed by electron cooling, clear evidence was found that the ion beam forms a one-dimensional ordered structure, a linear chain of ions. The strengths of stochastic cooling and electron cooling are complementary and can be combined favorably. Stochastic cooling is employed for pre-cooling of hot secondary beams followed by electron cooling to provide ultimate beam quality. In a similar manner, first experiments with carbon ions have been performed to use electron cooling as a pre-cooling method in combination with laser cooling.