Injection Phase-Space Study

Phase-Space Tracking including Second-Order Transport Matrices

The following plots show the positions in phase space (blue dots: x (mm), x' (mrad)) at the position of injection (s=511) of 500 injected electrons. The 500 tracked electrons are distributed randomly in phase space at injection. The turns are numbered such that injection occurs on turn 0. The flight direction of the electrons points out of the plane of the plot. (They're comin' atcha.) The convention for x' is such that a negative value indicates that the particle is moving away from the center of the ring (i.e. electrons are tracked 'backward' and positrons 'forward'). This study was performed using the lattice MORRIS_OLD_K9A18A000.FD96E_4S_15KG_INJ.

The ellipses show the 1-sigma (solid line) and 11-sigma (dotted line) contours of the stored electron beam before injection (i.e. before the pulsed bump). The ellipses show the 1-sigma (solid line) and 11-sigma (dotted line) contours of the stored electron beam before injection (i.e. before the pulsed bump). They are calculated using the pre-injection beam position in phase space and the Twiss parameters from the design optics with the pretzel off. The rms width of the stored beam is about 3 mm. With the pulsed bump, the position of the stored beam is brought to x=-3.1 mm, i.e. about 5 sigma from the inner vacuum chamber wall.

The yellow bands indicate the positions of the vacuum chamber walls. The x variable points away from the center of the ring. Since -x is plotted here, the yellow band on the right corresponds to the wall through which injection occurs.

Turn 0 (the injected bunch prior to entering CESR beam pipe)
Display PS0l.GIF