SLAC Accelerator Department The PEP-II Accelerator Status and General Plans John T. Seeman Assistant Director of the Technical Division Head of the Accelerator Department SLAC SPC Meeting December 3, 2004

SLAC Accelerator Department Topics Highlights of Run 4 of PEP-II Summer 2004 down General future plans

SLAC Accelerator Department Contributors to PEP-II SLAC LBNL LLNL With help from: –IHEP, Beijing, China –BINP, Novosibirsk, Russia –INFN, Frascati, Italy –CEA, Saclay, France –IN2P3, Paris, France –Caltech –BNL –Many people from the BaBar Collaboration –Visitors from CERN, DESY, Cornell, FNAL, KEK, …

SLAC Accelerator Department PEP-II e + e - Collider Use the SLAC linac as upgraded for the SLC for the injector. BaBar Detector Feedbacks Diagnostics LER RF 476 MHz HER RF 476 MHz 3.1 GeV positrons x 9 GeV electrons C = 2200 m

SLAC Accelerator Department PEP-II HER RF cavities

SLAC Accelerator Department PEP-II Interaction Region Components near BaBar HER LER Collision point BaBar

SLAC Accelerator Department PEP-II Machine Advisory Committee Reviews PEP-II Machine Advisory Committee –1) Jan 4-6, 1995 –2) August 24-25, 1995 –3) April 11-13, 1996 –4) January 6-8, 1997 –5) November 10-13, 1997 –6) December 14-16, 1998 –7) October 9-11, 2003 –8) April 15-17, 2004 –9) December 13-15, 2004

SLAC Accelerator Department Improvements in FY2004 –Peak luminosity: 6.6  9.2  –Number of bunches: 1050  1588 bunches by-2 pattern (24 long mini-trains) with 2% ion gap –Parasitic collision effects seen but small(<5%) –Electron Cloud (ECI) effects are small (<2%) –I  current 1500  2450 mA (3 RF stations) –I  current 1050  1550 mA (8 RF stations)  y * of 12  11 mm –All data now taken in trickle charge mode Both beams: LER in November, HER in March

SLAC Accelerator Department Daily Integration Record with Trickle Injection 710/pb LER I HER I Luminosity

SLAC Accelerator Department Peak luminosity of 9.21 x Record Peak Luminosity

SLAC Accelerator Department Trickle injection at the B Factories Best shift, no trickle PEP-II: ~5 Hz continuous KEKB: at ~5-10 min intervals Best shift, LER only trickle Nov 2003 Best shift, double trickle Mar 2004 PEP-II Lumi HER current LER current

SLAC Accelerator Department Trickle Charge: Length of Fill

SLAC Accelerator Department PEP-II Run Time Dist. FY 04 M. Stanek Pre-trickleLER-trickleDouble-trickle

SLAC Accelerator Department

SLAC Accelerator Department PEP-II Performance Measure: Peak Luminosity

SLAC Accelerator Department Run 1 Run 2 Run 3 Run 4 CD4 Design Performance

SLAC Accelerator Department

Total >240 fb -1 !

SLAC Accelerator Department Summer 2004 PEP-II Improvements IR2 south forward shield wall: Backgrounds Add another new LER RF station: Higher current Add a HER RF station by splitting up a current 4 cavity station into two 2 cavity stations: Higher current Two new “Frascati” longitudinal kickers in LER: More stability New electrodes for transverse kickers: More stability Add fans to all HER bellows: Cool Higher Order Modes (HOMs) Alignment work (quadrupole rolls): Smaller vertical emittance New LER synchrotron light monitor: Smaller vertical emittance IR NEG pump HOM reduction: Better lifetime and backgrounds New Support Tube Chiller: Higher currents

SLAC Accelerator Department New IR2 Shield Wall for BaBar IFR

SLAC Accelerator Department LER NEG Test chamber

SLAC Accelerator Department Lab test data of NEG outgassing as a function of temperature LER NEG Pump Temperatures Upstream LER side 350 °F

SLAC Accelerator Department Existing 3082 chamber BPM Chamber support Cooling bar NEG plenum NEG heater Quad extrusion

SLAC Accelerator Department Chamber shown inverted and plenum not shown for clarity SiC HOM absorber

SLAC Accelerator Department New bellows design with HOM absorber Kurita Novokhatski Weathersby

SLAC Accelerator Department IR Vacuum Chambers Vertex Bellows Q1/Q2 Bellows

SLAC Accelerator Department VTX Bellows Cooling Installation

SLAC Accelerator Department Forward VTX BLWS Cooling

SLAC Accelerator Department Thermo Model (May 2001) for 100 Watts Power input behind fingers.

SLAC Accelerator Department New Be bellows design SiC Cooling

SLAC Accelerator Department HER Single-Bunch Synchroscan Data at 16 MV

SLAC Accelerator Department Comparing Single-Shot and Synchroscan Data LER e+

SLAC Accelerator Department New LER Synchrotron Light Monitor Improved resolution Single bunch capabilities

SLAC Accelerator Department

Luminosity versus Crossing Angle Without parasitic crossing With parasitic crossing

SLAC Accelerator Department Luminosity Equation  y is the beam-beam parameter (~0.065)  I b is the bunch current (1 to 3 mA)  n is the number of bunches (~1600)  y * is the IP lattice optics function (vertical beta) (10 mm)  E is the beam energy (3.1 and 9 GeV)  Luminosity (10 33 cm -2 s -1 )

SLAC Accelerator Department Future luminosity increase factors ParameterPresentFutureLuminosity gain ratio Hardware and work needed LER current2450 mA4500 mATwo RF stations, new IR vacuum chambers HER current1550 mA2200 mA 1.61Two RF stations, new IR vacuum chambers y*y* 10.5 mm8.5 mm 1.24HER higher tunes, RF & power supplies work yy L H L H 1.17Tune plane, coupling, & IR work Parasitic  x 3.22 mm3.80 mm 1.08B1 magnet change (?) Total x 2.52

SLAC Accelerator Department Overall Parameters and Goals ParameterUnitsDesign Best in collision Future 2007 goal I+mA I-mA Number bunches y*y* cm yy , Luminosityx Integrated lumi / day pb Over five times design! Over three times design Twice design

SLAC Accelerator Department PEP-II Future Luminosity Parameters xx yy xx yy nI x*x* y*y* Lumi xx yy Unitscmmmnm mA mm mm x1E33 LER now LER HER now HER

SLAC Accelerator Department Expected PEP-II Delivered Integrated Luminosity Delivered as of end of fiscal yearPEP-II Projection“Delta” FY /fb117/fb FY FY FY FY FY FY

SLAC Accelerator Department Future Maintenance Down Activities Install LER-5 RF station Install HER-10 RF station Remove support tube for SVT work to fix radial ion pump and add an IR BPM Upgrade several high-power IR vacuum chambers (Be bellows, Q4, Q5, high power dump, Q2 bellows, LER abort window, straight section bellows …) HER lattice upgrade for lower momentum compaction and shorter bunches New RF comb filters New klystron linearizer New transverse digital feedback processors

SLAC Accelerator Department Conclusions PEP-II has reached a luminosity of 9.2  /cm 2 /s. PEP-II has delivered 710 pb -1 in one day. PEP-II has delivered over 117 fb -1 in Run 4! PEP-II has delivered over 256 fb -1 since May Trickle injection in both rings all of the time. Near term upgrades are going well. Planned upgrades toward 2.3  are on track. Progress on studying a Super-B-Factory.