ENERGY CALIBRATION AND TUNE JUMPS EFFICIENCY IN THE PP AGS

The AGS tune jump system consists of two fast quadrupoles used to accelerate the crossing of 82 horizontal intrinsic spin resonances. The fast tune jump of Qx = +0:04 within 100µs requires excellent localization of each of the 82 resonant conditions. Imperfect timing of the tune jumps results in lower eciency of the system and lower transmission of the polarization through the AGS acceleration cycle. Investigations during the end of the pp AGS Run13 revealedweaknessesintheenergymeasurementathighenergy, causing less than optimal timing of the tune jumps. A new method based on continuous polarization measurement to determine the energy during the acceleration cycle has been developed. Strong operational constraints were taken into account to provide a convenient system of energy measurement. This is also used to calibrate the usual determination of the energy based on revolution frequency of the beam or measured dipole magnetic field. This paper shows the tools developed and the results of the first tests during the AGS Run 14. Simulations of the expected tune jumps eciency