IUCF, Bloomington, Indiana
ORNL, Oak Ridge, Tennessee
SLAC, Menlo Park, California
Recently, discrepancies between model-based and observed linear optics, such as the tune and the closed orbit, have been observed in the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. Accurate accelerator modeling is very important for machine control during the ongoing power ramp up. The Orbit Response Matrix (ORM) method is applied here to find and correct errors in the linear optics of the SNS ring. With the closed orbit data (4472 data points), we are able to calibrate the strength of the steering magnets, the BPM gain factors, and 6 quadrupole power supplies. Current results and remaining challenges will be presented and discussed.
ORNL, Oak Ridge, Tennessee
Operating at 0.5 MW beam power on target, the Spallation Neutron Source (SNS) is already the world's most powerful pulsed neutron source. However, we are only one third of the way to full power. As we ramp toward full power, the control of the beam and beam loss in the ring will be critical. In addition to practical considerations, such as choice of operating point, painting scheme, and rf bunching, it may be necessary to understand and mitigate collective effects due to space charge, impedances, and electron clouds. In dedicated high intensity beam study shifts, we have already observed resistive wall, impedance driven, and electron cloud activity. The analysis and simulation of this data are important ongoing activities at SNS. This talk will discuss the status of this work, as well as other considerations necessary to the successful full power operation of SNS.
