Transverse RMS emittance evaluation based upon explicit and reasonable definitions of 100% and 95% beams

Ueno, Akira  ; Okoshi, Kiyonori ; Ikegami, Kiyoshi*; Takagi, Akira*; Oguri, Hidetomo  

In order to compare brightnesses of beams produced by different ion sources, a transverse emittance evaluation procedure with consistency and small ambiguity for different background noises is required. The procedure to evaluate emittances of beams produced by the Japan Proton Accelerator Research Complex (J-PARC) cesiated RF-driven H ion source is presented in this paper. The ambiguity in emittance evaluations is eliminated by defining uniquely 100% and 95% beams with a reasonably corrected beam-signal base-level. Two 95%-beam transverse normalized root mean square emittances of beams, which are produced with almost the same 2-MHz RF power and cesiation condition but with different background noise, are estimated as almost the same values by this procedure.