Transcript CESRc_collisions08012006

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.