Details

Autor(en) / Beteiligte

• Groening, L
• Barth, W
• Bayer, W
• Clemente, G
• Dahl, L
• Forck, P
• Gerhard, P
• Hofmann, I
• Kaiser, M S
• Maier, M
• Mickat, S
• Milosic, T
• Jeon, D
• Uriot, D

Titel

Experimental evidence of the 90 degrees stop band in the GSI UNILAC

Ist Teil von

• Physical review letters, 2009-06, Vol.102 (23), p.234801-234801

Ort / Verlag

United States

Erscheinungsjahr

2009

Quelle

American Physical Society Journals

Beschreibungen/Notizen

• In a particle accelerator with a periodic structure beam space charge force may excite resonant beam emittance growth if the particle's transverse phase advance approaches 90 degrees . A recent simulation study with the PARMILA code [D. Jeon, Phys. Rev. ST Accel. Beams 12, 054204 (2009)]10.1103/PhysRevSTAB.12.054204 has shown the feasibility of measuring the stop band of this fourth order resonance in the GSI Universal Linear Accelerator UNILAC and proposed its experimental verification, which is reported here. Measurements of transverse phase space distributions behind a periodically focusing structure reveal a fourfold symmetry characteristic of fourth order resonances as well as a resonance stop band above sigma_{0}=90 degrees per focusing cell. These experimental findings agree with results from three different beam dynamics simulation codes, i.e., DYNAMION, PARMILA, and TRACEWIN.