BIW08 - List of Authors (Babel, S.R.)

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Babel, S.R.

Paper	Title	Page
TUPTPF056	Closed Loop Wire Scanner Actuator Control for LANSCE Accelerator Beam Profile Measurements	244
	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

Paper

Title

Page

TUPTPF056

Closed Loop Wire Scanner Actuator Control for LANSCE Accelerator Beam Profile Measurements

244

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