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