e+/e- Vertical Beam Size during CESR-c Collisions E. Tanke, R. Holtzapple Data taken 8/1/2006

e+ Average Vertical Beam Size: Parasitic measurements made during CESR-c colliding beams. The vertical distribution is averaged over 100 turns (10,000 turn total). Fit each PMT profile to a Gaussian distribution to determine the sv(15.6 pixels/mm calibration). Two separate data sets taken. Typical 100 turn average e+ distribution. Note: Fit values shown here are in pixels not mm here

Average sv for two data sets. 100 turn pulse to pulse sv. e+ vertical beam size decreases along each train (except for train 3)!

Mean position of vertical distribution for each train. e+ vertical position increases along each train. Correlation between sv and mean position of the vertical distribution.

Single bunch current Slight correlation between beam size and current

e+ Single Turn Vertical Beam Size: Single turn vertical distribution for 500 turns. Typical single turn distribution Vertical beam size for bunch 1 over 500 turns Average single turn sv-Vertical beam size decreases along the train!

Single turn mean position along the trains Single bunch mean position for bunch 1.

e- Average Vertical Beam Size:: The vertical distribution is averaged over 100 turns (10,000 turn total). Fit each distribution to Gaussian to determine the vertical beam size (5.5 pixels/mm calibration) Vertical beam size growth along each train (except for train 1)! Average sv. Typical distribution 100 turn pulse to pulse sv.

Current/bunch increases along each train (except for train 7). Vertical position for each bunch along the train

e- Single Turn Vertical Beam Size: Single turn vertical distribution for 500 turns. Typical single turn distribution Single turn vertical beam size for bunch 1 over 500 turns Single turn mean position for bunch 1 over 500 turns

Summary The positron sv decreases along the 3 bunch trains. In addition, the relative mean position of the distribution increases along the train which results in a correlation between sv and the mean vertical distribution. The electron sv increases along the 3 bunch trains. From the single turn analysis it is evident that the e- sv jitter (standard deviation) is ~3 time larger than the e+ sv jitter. The e- mean position jitter is ~2.5 times larger than the e+ mean position jitter.