Measurement and simulation of whole beam brightness on the ETA-II (Experimental Test Accelerator-II) linear induction accelerator

Measurement of beam radius as a function of focusing strength of an upstream solenoidal field allows simultaneous determination of the beam energy, brightness and tilt of the phase space ellipse. On ETA-II beam radius has been measured by analyzing foil emitted Cherenkov light with a gated (5 ns) image intensified CCD camera. The beam energy measurement is corroborated with a spectrometer magnet and core brightness with a two hole emittance diagnostic. For a 6 MeV, 1.6 kA beam, the whole beam brightness was measured to be 4.0 {times} 10{sup 8} A/(m-rad){sup 2} with an inner core (few percent) brightness of 1.2 {times} 10{sup 9} A/(m-rad){sup 2}. The data was simulated with a particle transport code that includes the effects of energy sweep and magnetic misalignment. The code predicts a halo produced by an orbital resonance that is also observed experimentally.