PEP-II MAC Highlights
•
1.2 x 1034
Vacuum issues
John Seeman
PEP- II Linac Accelerator Systems Department
Future PEP-II Overall Parameters and Goals
Parameter Units Design Present best 2007 goal
I+ mA 2140 2940 4000
I- mA 750 1940 2200
Number bunches
1658 1722 1732
y* mm 15-20 10 8.5
Bunch length mm 15 11-12 9
y 0.03 0.047-0.065 0.054-0.07
Luminosity x1033 3 12 20
Int lumi / day
pb-1 130 911 1300
7 times design4 times design
John Seeman
PEP-II Upgrades
• Goal: A factor of two in PEP-II luminosity • (1.2 2 x1034/cm2/s) will come from:
– Increasing each beam current by 40%.
– Lowering y* from 11 to 8.5 mm giving 20%.
– Increasing the beam-beam parameters by 10%.– Keeping detector backgrounds at the predicted
levels.– Maintaining (and improving) accelerator reliability.
John Seeman
Vertical waist has to be a function of x:
Z=0 for particles at –x (- x/2 at low current)
Z= x/ for particles at + x (x/2 at low current) Crabbed waist realized with a sextupole in phase with the IP in
X and at /2 in Y
2Sz
2Sx
z
x
2Sx/
2Sz*
e-e+Y
Crabbed waist removes bb betratron couplingIntroduced by the crossing angle
DAFNE Upgrade with Large Piwinski Angle & Crab WaistPantaleo Raimondi
Normal
Beam Abort
Cooling
Beam Injection
MakotoTobiyama
movement of KEKB chambers due to rapid change of beam current
QD1E.21 QF2E.41 B2E.96 QD3E.35 QF4E.35 QEAE.42 QD5E.42 B2E.95 QF6E.21
QF6E.21 B2E.94 QD5E.41 QEAE.41 QF4E.34 QD3E.34 B2E.93 QF2E.40 QD1E.20
+0.28-0.16
+0.13-0
+0.48-1.22
+0.55-1.02
+0.27-0
+1.9-0.21
+0-0
+0.02-0
+0.08-0.01
+0.47-0.23
+0.43-0.72
+0.49-1.81
+0.48-1.86
+0.58-1.83
+1.32-0.53
+0.26-0.02
+0-0
+0.15-0.14
+1.55-0.76
+0.25-0.83
+0.48-1.75
+0.45-0.13
+0.16-0
2006.06.02 - 06.07Measurements by dial gauge
Large movement : Both sides of B-chamber 、 Long-Q-chamber+BPM
+:outside 、 -:insidee-beam
x1
x2+1
Makoto Tobiyama
Move to Test Stand for Cool-down & High Power Test
K. Hosoyama, et al
MakotoTobiyama