BNL, Upton, Long Island, New York
NSCL, East Lansing, Michigan
CERN, Geneva
Isochronous cyclotrons, rings for precise nuclear mass spectrometry, and some isochronous-optics light sources with extremely short bunches are operated or proposed to be operated in the isochronous or almost isochronous regime. Also, many hadron synchrotrons run in the isochronous regime for a short period of time each acceleration cycle during transition crossing. The longitudinal motion is “frozen” in the isochronous regime that leads to accumulation of the integral of the longitudinal space charge force. In low-gamma hadron machines, this can cause a fast growth of the beam energy spread even at modest beam intensities. In this paper, I discuss specifics of space charge in the isochronous regime and present experimental results obtained in the Small Isochronous Ring, developed at Michigan State University specifically for studies of space charge in the isochronous regime.
