Transverse Mode-Coupling Instability in the CERN Super Proton Synchrotron

Journal Article · Wed Jun 08 04:00:00 EDT 2005 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.1949567· OSTI ID:20722802

Metral, E; Arduini, G; Benedetto, E; Burkhardt, H; Shaposhnikova, E ^[1]; Rumolo, G ^[2]

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1. CERN, Geneva (Switzerland)
2. GSI, Darmstadt (Germany)

A vertical single-bunch instability has been observed in 2003 right after injection at 26 GeV/c in the CERN Super Proton Synchrotron (SPS). High-intensity proton bunches ({approx}1.2 1011 p/b) with low longitudinal emittance ({approx}0.2 eVs) are affected by heavy losses after less than one synchrotron period. Such phenomenon has already been observed with leptons in many machines, e.g. in the SPS, or with protons at transition, e.g. in the CERN Proton Synchrotron (PS). However, to the authors' knowledge, it is the first time with protons far from transition. The absence of transverse mode-coupling instability in hadron machines is generally explained by three mechanisms: (i) the intensity threshold for the longitudinal microwave instability is generally lower than for the transverse mode-coupling instability (ii) the intensity threshold due to mode-coupling between the two lowest azimuthal modes increases with space charge, and (iii) the intensity threshold increases with bunch length (in the long-bunch regime). In this talk measurements performed in the SPS are compared to analytical and simulation predictions.

• OSTI ID: 20722802
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 773; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BEAM BUNCHING
BEAM INJECTION
CERN SPS SYNCHROTRON
COMPUTERIZED SIMULATION
COUPLING
GEV RANGE
INSTABILITY
LEPTONS
MICROWAVE RADIATION
PARTICLE BEAMS
PARTICLE LOSSES
PROTONS
SPACE CHARGE