Accelerator Plans at KEK John W. Flanagan, KEK Super B Factory Workshop Honolulu 19 January 2004.
Accelerator R&D Results from the B-factory
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DOE Review Jun 12-14, 2007 R&D from PEP-II Accelerator R&D Results from the B- factory M. Sullivan PEP-II run coordinator
description
Accelerator R&D Results from the B-factory. M. Sullivan PEP-II run coordinator. Outline. PEP-II Parameters Vacuum designs RF systems Bunch by bunch feedbacks High-current running Synchrotron radiation power HOM power IR design SuperB IR design Summary. PEP-II Rings. BaBar Detector. - PowerPoint PPT Presentation
Transcript of Accelerator R&D Results from the B-factory
DOE ReviewJun 12-14, 2007
R&D from PEP-II
Accelerator R&D Results from the B-factory
M. Sullivan
PEP-II run coordinator
DOE ReviewJun 12-14, 2007
R&D from PEP-II
Outline
• PEP-II Parameters– Vacuum designs– RF systems– Bunch by bunch feedbacks
• High-current running– Synchrotron radiation power– HOM power
• IR design– SuperB IR design
• Summary
DOE ReviewJun 12-14, 2007
R&D from PEP-II
PEP-II Rings
BaBar Detector
DOE ReviewJun 12-14, 2007
R&D from PEP-II
PEP-II tunnel
DOE ReviewJun 12-14, 2007
R&D from PEP-II
PEP-II parameters
Circumference (m) 2200RF frequency (MHz) 456Number of RF buckets 3492Number of bunches 1730Bunch spacing (m) 1.26 LER HERBeam current (A) 2.9 (2.99) 1.85 (1.9)Particles per bunch 81010 51010
Beam energy (GeV) 3.1 9Collision beam sizes (m) 100x5Collision Head-onLuminosity (cm-2 sec-1) 1.21034
Highest beam currents and more positrons than anyone else
DOE ReviewJun 12-14, 2007
R&D from PEP-II
Vacuum Systems
• HER– Long (5.4 m) PEP-I dipoles led to distributed ion pumps
(DIPS)– Copper system
• LER– Short (0.45 m) dipoles to decrease the damping time led to
ante-chambers with photon stops and massive titanium sublimation pumps (TSPs)
– Aluminum system (TiN)• Base pressures are less than a nTorr• Dynamic pressures are a few nTorr• More Amp-hours than any other accelerator
– Over 50,000 Amp-hrs for the LER– Over 30,000 Amp-hrs for the HER
DOE ReviewJun 12-14, 2007
R&D from PEP-II
RF System and Feedbacks
• RF systems– Minimal stored energy– Power efficient– Beam loading is high– State of the art low-level feedback system to
control klystron power and phase
• Fast feedback systems to control multi-bunch instabilities in the transverse and longitudinal dimensions– Longitudinal system has been installed in several
other storage rings
DOE ReviewJun 12-14, 2007
R&D from PEP-II
High Beam Currents• Synchrotron Radiation power– 6.4 MW for the HER at 1.8 A– 2.3 MW for the LER at 3 A
• HOM power– Absorbing elements– Pump screens– Bellows screens
• Ion gap – Gap is now 1% -- ions have only seen when the
vacuum is high
• Electron cloud– Successfully controlled by solenoid windings
DOE ReviewJun 12-14, 2007
R&D from PEP-II
HOM power damage
RF seal between two flanges in the HER
DOE ReviewJun 12-14, 2007
R&D from PEP-II
Absorber designs
S. WeathersbyA. Novokhatski
DOE ReviewJun 12-14, 2007
R&D from PEP-II
Design for a HOM Absorber Module
DOE ReviewJun 12-14, 2007
R&D from PEP-II
Bellows Design with Exposed Tiles
DOE ReviewJun 12-14, 2007
R&D from PEP-II
New Absorber Design
Absorber tiles are now behind the bellows fingers and the spacing between the fingers is quite large to allow high frequency RF to pass through
DOE ReviewJun 12-14, 2007
R&D from PEP-II
IR Design
• Uses permanent magnets for accelerator components inside the detector magnetic field– Require no power– Are always on – reduces the probability
that an uncontrolled beam will crash into the detector
–Maintenance free– Self-shielding
DOE ReviewJun 12-14, 2007
R&D from PEP-II
PEP-II Interaction Region
e e
BaBar Detector
DOE ReviewJun 12-14, 2007
R&D from PEP-II
IR Layout
DOE ReviewJun 12-14, 2007
R&D from PEP-II
Super B Factory
• Worked on an interaction region design for a Super B Factory– The design incorporates super-conducting elements as well
as permanent magnet elements for the final focus optics
• Similar beam currents and storage ring sizes as PEP-II– Ring optics, HOM issues, beam stability…– Trickle injection – pioneered at PEP-II and KEKB is a crucial
ingredient for any future high-current collider
• About one FTE at SLAC works on the SuperB to support the world wide effort . Not directed to any one particular site yet…
DOE ReviewJun 12-14, 2007
R&D from PEP-II
Super B Interaction RegionSuperB Interaction Region
0
10
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-10
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-300 2.5 5 7.5-2.5-5-7.5
cm
m
QD0 QD0
QD0H
QD0HB00L
B00H
QF1 QF1
B0LB0H
B0L
B0H
QF1QF1
LERHER
M. SullivanNov. 11, 2006SB_IT_ILC_G3
DOE ReviewJun 12-14, 2007
R&D from PEP-II
SuperB IR Closeup
QD0 QD0
QD0H
QD0HB00LB00H
QF1 QF1
QF1QF1
B0L
B0H
B0H
B0L
SuperB Interaction Region
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10
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-10
-200 1 2 3-1-2-3m
cm
M.SullivanNov. 13, 2006SB_IT_ILC_G3_300
DOE ReviewJun 12-14, 2007
R&D from PEP-II
Summary• PEP-II is a working accelerator with high-
current rings
• Many of the issues for the ILC damping rings have been or can be studied at PEP-II
• Over 100 accelerator papers have been written about PEP-II with regard to the high-current performance
• As we increase beam currents, PEP-II will move further into the frontier of high-current storage rings
