CERN Accelerating science

Article
Title	The Production of Negative Lithium Beams by Charge Exchange in Cesium Vapours
Author(s)	Re, Maurizio ; Bilheux, Jean-Christophe ; Chines, Francesco ; Cuttone, Giacomo ; Menna, Mariano ; Messina, Esteban ; Stracener, Dan
Affiliation	(INFN/LNS, Catania) ; (ORNL, Oak Ridge, Tennessee)
Publication	2005
In:	21st IEEE Particle Accelerator Conference, Knoxville, TN, USA, 16 - 20 May 2005, pp.898
Subject category	Accelerators and Storage Rings
Abstract	These measurements were carried out at the Holifield Radioactive Ion Beam Facility of the Oak Ridge National Laboratory (ORNL-HRIBF) by researchers from the Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS), Catania, Italy and local staff. The Charge Exchange Cell (CEC) consisted of a vacuum chamber containing cesium vapours at a variable temperature, T, in which positive ions accelerated from an ion source were transformed into negative ones by collisions with the Cs atoms. The main goal of this test was to measure the production efficiency for 7Li- ions at different operating conditions, such as 7Li+ beam energy (5 to 55 keV) and Cs temperature (190 to 300 °C). Moreover, the efficiency measurements performed with a 6Li+ projectile beam gave clear indications about the isotopic shift effect. These results are useful to estimate the charge exchange efficiency for 8, 9Li, which will be the first radioactive beams to be produced at the EXCYT facility (EXotics with CYclotron and Tandem). The data showed that the charge exchange efficiency at the minimum energy suitable for beam handling (20-25 keV) is around 1%.