Test of a low gamma transition optics

By increasing the difference between the beam energy and gamma transition one can, in theory, raise the limit for the on-set of the so-called microwave instability and thus increase the maximum intensity per bunch. This is of interest for the high intensity beams demanded from the SPS by the LHC. A fully fledged realization of a low gamma transition scheme in the SPS would involve the installation of additional quadrupoles, however by moving the tunes near to a multiple of the super period of the SPS it is possible to artificially lower gamma transition. To this end an optics was developed with tunes close to 24. 26 GeV protons were injected into the MD cycle on which this optics had been installed. Comparative longitudinal impedance measurements were made on both the low gamma transition optics and the normal fixed target optics.