ICALEPCS2013 - List of Authors (Baily, S.A.)

Paper	Title	Page
THPPC112	The LANSCE Timing Reference Generator	1321
	R.B. Merl, S.A. Baily, E. Björklund, R.C. Clanton, F.E. Shelley LANL, Los Alamos, New Mexico, USA
	The Los Alamos Neutron Science Center is an 800 MeV linear proton accelerator at Los Alamos National Laboratory. For optimum performance, power modulators must be tightly coupled to the phase of the power grid. Downstream at the neutron scattering center there is a competing requirement that rotating choppers follow the changing phase of neutron production in order to remove unwanted energy components from the beam. While their powerful motors are actively accelerated and decelerated to track accelerator timing, they cannot track instantaneous grid phase changes. A new timing reference generator has been designed to couple the accelerator to the power grid through a phase locked loop. This allows some slip between the phase of the grid and the accelerator so that the modulators stay within their timing margins, but the demands on the choppers are relaxed. This new timing reference generator is implemented in 64 bit floating point math in an FPGA. Operators in the control room have real-time network control over the AC zero crossing offset, maximum allowed drift, and slew rate - the parameter that determines how tightly the phase of the accelerator is coupled to the power grid. LA-UR-13-21289

Paper

Title

Page

The LANSCE Timing Reference Generator

1321

R.B. Merl, S.A. Baily, E. Björklund, R.C. Clanton, F.E. Shelley
LANL, Los Alamos, New Mexico, USA

The Los Alamos Neutron Science Center is an 800 MeV linear proton accelerator at Los Alamos National Laboratory. For optimum performance, power modulators must be tightly coupled to the phase of the power grid. Downstream at the neutron scattering center there is a competing requirement that rotating choppers follow the changing phase of neutron production in order to remove unwanted energy components from the beam. While their powerful motors are actively accelerated and decelerated to track accelerator timing, they cannot track instantaneous grid phase changes. A new timing reference generator has been designed to couple the accelerator to the power grid through a phase locked loop. This allows some slip between the phase of the grid and the accelerator so that the modulators stay within their timing margins, but the demands on the choppers are relaxed. This new timing reference generator is implemented in 64 bit floating point math in an FPGA. Operators in the control room have real-time network control over the AC zero crossing offset, maximum allowed drift, and slew rate - the parameter that determines how tightly the phase of the accelerator is coupled to the power grid.
LA-UR-13-21289