Author: Prokop, M.S.
Paper Title Page
THPPC090 Robust Control of a Two-Input Two-Output (TITO) Multistate Cavity RF System ith Mismatched Uncertainty 3494
  • S. Kwon, M.S. Prokop, A. Scheinker
    LANL, Los Alamos, New Mexico, USA
  A RF cavity is well modeled as a linear two input two output (TITO) system in the Inphase/Quadrature (IQ) coordinates and is both controllable and observable. Whether it is due to the beam loading or Lorentz force detuning of a superconducting cavity, a cavity frequency detuning can be modeled as a matched uncertainty. The cavity field of a TITO cavity system with a matched uncertainty is controlled by output feedback or state feedback, whose error bound is made arbitrary small. Because of the building cost of the RF system, the single RF source (single klystron)-multicavity structure is sometimes used. This structure is described as a two-input multiple-output (TIMO) system. The control problem is not a simple extension of the single TITO system. Though the controllability and observability are preserved, the matched uncertainty of the TITO cavity system caused by cavity detuning becomes a mismatched uncertainty. The error bound of outputs is made arbitrary small by a control, only boundedness of the cavity fields of each TITO subsystem is guaranteed. In this paper, the properties of the TITO and the TIMO cavity RF systems are investigated.  
THPPP097 Diagnostic Pulse for Single-particle-like Beam Position Measurements During Accumulation/Production Mode in the Los Alamos Proton Storage Ring 3960
  • J.S. Kolski, S.A. Baily, E. Björklund, G.O. Bolme, M.J. Hall, S. Kwon, M.P. Martinez, M.S. Prokop, F.E. Shelley, P.A. Torrez
    LANL, Los Alamos, New Mexico, USA
  Beam position monitors (BPMs) are the primary diagnostic in the Los Alamos Proton Storage Ring (PSR). Injecting one turn, the transverse motion is approximated as a single particle with initial betatron position and angle (x0 and x0'). With single-turn injection, we fit the betatron tune, closed orbit (CO), and injection offset (x0 and x0' at the injection point) to the turn-by-turn beam position. In production mode, we accumulate multiple turns, the transverse phase space fills after 5 injections (horizontal and vertical fractional betatron tunes ~0.2) resulting in no coherent betatron motion, and only the CO may be measured. The injection offset, which determines the accumulated beam size and is very sensitive to steering upstream of the ring, is not measurable in production mode. We describe our approach and ongoing efforts to measure the injection offset during production mode by injecting a ‘‘diagnostic'' pulse ~50 us after the accumulated beam is extracted. We also study the effects of increasing the linac RF gate length to accommodate the diagnostic pulse on the production beam position, transverse size, and loss.