Title :
A fast chopper for programmed population of the longitudinal phase space of the AGS
Author :
Brennan, M. ; Ahrens, L. ; Alessi, J. ; Brodowski, J. ; Kats, J. ; van Asselt, W.
Author_Institution :
Brookhaven Nat. Lab., Upton, NY, USA
Abstract :
A fast beam chopper has been built that can produce an arbitrary pulse program of the 200-MeV H- beam for synchronous injection into moving RF buckets in the Alternating Gradient Synchrotron (AGS). The chopper will eliminate RF capture losses and can be used to tailor the initial distribution in longitudinal phase space by varying the pulse parameters, width and phase, on a bunch-by-bunch time scale during multiturn injection. The chopper also serves as a studies tool, because it can provide controllable beam intensity with fixed longitudinal emittance (or conversely) and/or missing bunches. It is an electrostatic deflection device with 15 pairs of plates located above and below the 35-keV H- beam between the ion source and the RFQ (radio-frequency quadrupole) preinjector. The plates are spaced 26-mm apart in the beam direction and connected as a slow-wave structure by coaxial cables. They are driven to ±760 V by DC-coupled pulse generators. Beam current rise and fall times are less than 10 ns
Keywords :
beam handling equipment; proton accelerators; synchrotrons; 10 ns; 200 MeV; 35 keV; 760 V; AGS; Alternating Gradient Synchrotron; DC-coupled pulse generators; H- beam; beam chopper; coaxial cables; electrostatic deflection device; fast chopper; fixed longitudinal emittance; longitudinal phase space; moving RF buckets; multiturn injection; programmed population; slow-wave structure; Acceleration; Choppers; Controllability; Electrostatics; Energy capture; Ion beams; Laboratories; Particle beam injection; Space charge; Space vector pulse width modulation;
Conference_Titel :
Particle Accelerator Conference, 1989. Accelerator Science and Technology., Proceedings of the 1989 IEEE
Conference_Location :
Chicago, IL
DOI :
10.1109/PAC.1989.73379
