W.P. LYSENKO, J.D. GILPATRICK, L.J. RYBARCYK, J.D. SCHNEIDER, H.V. SMITH, Jr., L.M. YOUNG (Los Alamos National Laboratory), M.E. SCHULZE (General Atomics)
The transverse phase-space properties of the 6.7-MeV proton beam from the Low Energy Demonstration Accelerator (LEDA) [1] radio-frequency quadrupole (RFQ) [2] were measured by recording wire scanner profiles at one position in the high-energy beam transport (HEBT) as a function of the gradient of one of the HEBT quadrupoles [3,4]. We determined the Courant-Snyder parameters of the RFQ beam by fitting the measured data to a computer model of the HEBT. Strong space charge effects had to be taken into account when fitting the data. We considered several models: a simple semi-analytic model, the (linear) TRACE 3-D code, and 2-D and 3-D particle codes that include nonlinear space-charge effects. The importance of various beam-physics effects were determined by comparing model predictions with details of the measured wire scanner profiles . There is beam behavior in these emittance measurement that is not present in normal HEBT operation. With this information, we could estimate the accuracy of our fits. We compare our measurements with predictions of the RFQ design code (PARMTEQM)
[1] H.V. Smith, Jr. and J.D. Schneider, 'Status Update on the Low-Energy Demonstration Accelerator (LEDA),' this conference.
[2] L.M. Young, et al., 'High Power Operations of LEDA,' this conference.
[3] M.E. Schulze, et al., 'Beam Emittance Measurements of the LEDA RFQ,' this conference.
[4] J.D. Gilpatrick, et al., 'LEDA Beam Diagnostics Instrumentation: Measurement Comparisons and Operational Experience,' submitted to the Beam Instrumentation Workshop 2000, Cambridge, MA, May 8-11, 2000.
*Work supported by the US Department of Energy
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