• J.D. Sedillo, J.D. Gilpatrick, F. Gonzales, J.F. Power
  LANL, Los Alamos, New Mexico

The LANSCE accelerator facility utilizes 110 wire scanner devices to monitor the accelerator's charged particle beam. The LANSCE facility's existing wire scanner control systems have remained relatively unchanged since the LANSCE accelerator became operational in the 1970's. The evolution of motion control technologies now permits the development of a wire scanner motion control system that improves in areas of energy efficiency, precision, speed, resolution, robustness, upgradeability, maintainability, and overall cost. The purpose of this project is to research the capabilities of today's motion control products and analyze the performance of these products when applied to a wire scanner beam profile measurement. This experiment's test bed consists of a PC running LabVIEW, a National Instruments motion controller, and a LEDA (Low Energy Demonstration Accelerator) actuator. From this experiment, feedback sensor performance and overall motion performance (with an emphasis on obtaining maximum scan speed) has been evaluated.

• S. Cohen, S.R. Babel
  Bira, Albuquerque, New Mexico
• D.A. Bonal, M.M. Ravindran
  National Instruments, Austin
• J.D. Gilpatrick, J.D. Sedillo
  LANL, Los Alamos, New Mexico

The design and test of a new beam-profile-wire-scanner actuator for the LANSCE* 800-MeV proton linear accelerator is described. Previous actuator implementations use open-loop stepper-motor control for position indexing. A fixed-frequency, fixed-duration pulse train is sent to the stepper motor driving the linear actuator. This has lead to significant uncertainties in position, mechanical resonances and electrical noise. A real-time, closed loop control system has been developed at tested for more repeatable and accurate positioning of beam sense wires. The use of real-time controller allows one to generate a velocity profile for precise, resonance-free wire position indexing. High radiation levels in the beam tunnel, dictate the use of an electro-magnetic resolver, typically, used in servo applications, as the position feedback element. Since the resolver is an inherently analog device sophisticated digital signal processing is required to generate and interpret the wave forms that the feedback mechanism needs for positioning. All of the electronic and computational duties are handled in one National Instruments compact RIO real-time chassis with FPGA.**

*Los Alamos Neutron Science Center
**Field Programmable Gate Array