SIMULATION RESULTS OF BENT CRYSTAL EXTRACTION IN THE TEVATRON

We present simulation results describing parasitic extraction of a hig h energy proton beam from the Tevatron via a bent Silicon crystal - de monstrated recently by E853 experiment at Fermilab, In a spirit of par asitic extraction the transverse phase-space of the beam is initially prepared, so that only high amplitude particles from the beam halo int eract with the Silicon crystal (inserted into the beam), without affec ting the 'core' of the beam. As a result of the beam halo-crystal inte raction (multiple scattering and wide angle nuclear interaction), some fraction of the beam halo channels into the crystal - a multi-turn ex traction occurs. The ultra strong focusing environment of a crystal ch annel combined with the externally imposed curvature (vertically bent crystal) provide excellent guiding features of an efficient extraction line. Here, we use a realistic model of the Tevatron lattice to descr ibe the beam optics of the machine. Presented phase-space simulation d escribes a 'kick' mode of the E853 experiment. To enhance the beam hal o interaction with the crystal, the proton beam is initially excited b y firing a transverse kicker, which induces horizontal oscillations of the beam centroid on the subsequent turns. A realistic phase-space tr acking yields turn-by-turn channeling efficiency, which sheds light on multi-turn extraction mechanisms. It also allows us to optimize exper imental configuration parameters for maximum extraction efficiency.