Commissioning of the high energy combined ramp and squeeze

During 1998, because of the need to avoid short bunch lengths, the dampingand emittance wigglers were kept on in the ramp to higher energies. Some lifetime problems were noted between 50 and 60 GeV. A possible causebeing insufficient momentum aperture of the squeezed 102/90 optics with thewigglers on. One possible way to avoid this situation is to squeeze at highenergy after the wigglers have been brought down.To achieve this a hyperrun was constructed that ramped with the injectionoptics until 92 GeV, then performed a combined ramp & vertical squeeze to 94.5GeV, beta*y = 5 cm.A horizontal squeeze from 2.0 to 1.25 m is then performed at constant energy beforefinally squeezing beta*y to 4 cm.In the process the opportunity was taken to remove solenoid and wiggler orbitcompensation, flatten all corrector functions at constant strength, andthe re-apply solenoid, and wiggler, compensation. This has led to a muchstabler ramp.