M. E. SCHULZE**, J. D. GILPATRICK, W. P. LYSENKO, L. J. RYBARCYK, J. D. SCHNEIDER, H. V. SMITH, JR, L. M. YOUNG
The Low-Energy Demonstration Accelerator (LEDA) radio-frequency quadrupole (RFQ) is a 100% duty factor (CW) linac that delivers >100 mA of H+ beam at 6.7 MeV. The 8-m-long, 350-MHz RFQ structure accelerates a dc, 75-keV, 110-mA H+ beam from the LEDA injector with >90% transmission. LEDA  consists of a 75-keV proton injector, 6.7-MeV, 350-MHz cw RFQ with associated high-power and low-level rf systems, a short high-energy beam transport (HEBT) and high-power (670-kW cw) beam dump. The beam emittance is inferred from wire scanner measurements of the beam profile at a single location in the HEBT. The beam profile is measured as a function of the magnetic field gradient in one of the HEBT quadrupoles. As the gradient is changed the rms spot size passes through a transverse waist. Measurements are presented for peak currents between 25 and 100 mA. Different approaches to analyzing the data are described.
 H.V. Smith, et al., 'Update On The Commissioning Of The Low-Energy Demonstration Accelerator (LEDA) Radio-Frequency Quadrupole (RFQ),' Proceeding 1999 ICFA Workshop on The Physics of High Brightness Beams, in press
* Work supported at LANL under contract to the US DOE
** General Atomics
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