Stopping energetic heavy-ions in one-bar helium: broad incident momentum distributions

✍ Scribed by L. Weissman; D.A. Davies; P.A. Lofy; D.J. Morrissey

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 462 KB
• Volume: 531
• Category: Article
• ISSN: 0168-9002
• DOI: 10.1016/j.nima.2004.05.093

✦ Synopsis

Various tests for stopping energetic 32 P fragments in a 50 cm gas cell filled with helium were performed. The fraction of ions stopped in the gas was measured as a function of the width of the incident beam momentum distribution. The use of a shaped degrader placed in a dispersive plane before the gas cell significantly improves the stopping efficiency in gas. A stopping efficiency of 35% was obtained for fragments with the broadest momentum distribution, which was an improvement of approximately 80%. Qualitative agreement between the experimental results and stopping power calculations was obtained.