Trickle-Charge: a New Operational Mode for PEP-II Page: 3 of 3

1 1091 1

8 10
C
t 610
Gun Electronics Repair
0
4108
2108
0
40 60 80 100 120
12-Feb to 5-May (days from Jan 1)
Figure 5. Intensity jitter versus day.
In figure 6, timing jitter out of the damping ring is seen
as energy jitter in the bunch compressor. This timing jitter
will cause changes in the six dimensional beam
distribution. The reduction of this timing jitter was
accomplished by empirical adjustments of the electron
damping ring RF system.
0.8
0.7 I

0.6
0.5-
0.4
0.3
0.2
0.1
0L
40

I

Damping Ring RF Adjustment
60 80 100 120

500
0
0
0
-500
-1000

-1500
75

Feedback Turned On

80 85 90 95 100 105
16-Mar to 12-Apr (days from Jan 1)

Figure 7. Signal from trajectory stabilization feedback.
SUMMARY
Key to the success (see figure 8) of trickle-charge has
been the diagnostics provided by BaBar, the tuning down
different sources of jitter, new stabilization feedbacks,
and moving the stored beams closer to the septum[1].
600

500
400
en
300
200
~-100

0

Both Trickle

LER Trickle

o 0 0 0 0 0 0
C) U - <C C. P -

12-Feb to 5-May (days from Jan 1)
Figure 6. Energy in MeV is indicative of beam phase jitter
(time jitter) out of the electron damping ring.
INJECTOR TRAJECTORY
STABILIZATION
The injecting beams for both rings show trajectory
drifts over the time scale of hours or longer. Stabilizing
the incoming beams very near the PEPII rings has been
successful in the case of positron injection into the LER.
Figure 7 shows the stabilizing effect of the feedback on
the vertical trajectory. A similar feedback is planned for
the electrons.

Figure 8. Daily Avg. Luminosity increase with trickle
ACKNOWLEDGEMENTS
We would like to thank Mark Petree, and Mike Stanek
for their operationally useful tools for taking and
analyzing "flier" data.
REFERENCES
[1] F. J. Decker et. al, "Diagnosing the PEPII Injection
System" EPAC'04, Lucerne, July 2004.
[2] F. J. Decker et. al, "Injection Related Background due
to the Transverse Feedback" PAC'03, Portland, OR,
USA, May 2003.

1000

d

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Kozanecki, W.; Colocho, W. S.; Decker, F. -J.; Ecklund, S.; Fisher, A. S.; Iverson, R. H. et al. Trickle-Charge: a New Operational Mode for PEP-II, article, May 9, 2005; [Menlo Park, California]. (https://digital.library.unt.edu/ark:/67531/metadc883371/m1/3/ocr/: accessed May 24, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.

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