the last year of pep-ii b-factory operation · the last year of pep-ii b-factory operation john...
TRANSCRIPT
![Page 1: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/1.jpg)
Accelerator Systems Division
The Last Year of PEP-II B-Factory Operation
John Seeman for the PEP-II TeamStanford Linear Accelerator Center
EPAC 2008 GenoaJune 24, 2008
![Page 2: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/2.jpg)
Accelerator Systems Division
The PEP-II Team
• PEP-II was constructed by SLAC,LBNL, and LLNL with help fromBINP, IHEP, BaBar collaboration.Many thanks to theUS Department of Energyand members of the Machine Advisory Committee.
1x1034
![Page 3: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/3.jpg)
Accelerator Systems Division
PEP-II Layout
Two rings: Circumference = 2.2 km.
![Page 4: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/4.jpg)
Accelerator Systems Division
The PEP-II Collider
![Page 5: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/5.jpg)
Accelerator Systems Division
LER Magnets and Aluminum Vacuum System (LBNL)
Magnets madeby our ChineseIHEP collaborators
AntechambersReduce Electron-Cloud-Instability
High powerphoton stops
LER SR power= 2 MW.
![Page 6: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/6.jpg)
Accelerator Systems Division
LER Wiggler Chamber (LLNL)
![Page 7: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/7.jpg)
Accelerator Systems Division
PEP-II HER Copper Vacuum System (SLAC)
Cu chambersabsorbing100 W/cm of synchrotronradiation
Total SR power = 10 MW in the
HER
![Page 8: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/8.jpg)
Accelerator Systems Division
PEP-II interaction region layout
Vertical LayoutHorizontal layout
![Page 9: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/9.jpg)
Accelerator Systems Division
PEP-II Interaction Region Components near BaBar
HER
LER
Collision point
BaBar
![Page 10: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/10.jpg)
Accelerator Systems Division
How the beams enter and exit the PEP-II Interaction Region
![Page 11: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/11.jpg)
Accelerator Systems Division
IR Permanent Magnets
![Page 12: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/12.jpg)
Accelerator Systems Division
Interaction region vacuum chambers
•
![Page 13: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/13.jpg)
Accelerator Systems Division
Interaction Region Support Tube
Be chamber
SiliconVertexTrackerSVT
![Page 14: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/14.jpg)
Accelerator Systems Division
The BaBar Detector•
![Page 15: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/15.jpg)
Accelerator Systems Division
Brief PEP-II History• 1987: Physics: asymmetrical energies preferred.• 1991: First PEP-II CDR.• 1993: Second CDR.• 1994: Construction started.• 1997: First stored HER e- beam.• 1998: First stored LER e+ beam.• 1998: First collisions July 23, 1998.• 1999-2007: Y4S data for BaBar (433 fb-1)• 2008: Y2S (30 fb-1), Y3S (15 fb-1), and small
energy scan for BaBar.• 2008: Turned off PEP-II April 7, 2008.
![Page 16: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/16.jpg)
Accelerator Systems Division
PEP-II Peak Luminosity by Month (1999-2008)
•
Design
![Page 17: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/17.jpg)
Accelerator Systems Division
Design of 135 pb-1
![Page 18: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/18.jpg)
Accelerator Systems Division
![Page 19: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/19.jpg)
Accelerator Systems Division
PEP-II total integrated luminosity: 557 fb-1
![Page 20: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/20.jpg)
Accelerator Systems Division
Luminosity Equation for a Circular e+e- Collider
ξy is the beam-beam parameter (~0.06) Ib is the bunch current (1 to 3 mA) n is the number of bunches (~1700) βy
* is the IP lattice optics function (vertical beta) (10 mm) E is the beam energy (3.1 and 9 GeV) (fixed) Luminosity (1033 cm-2 s-1)
*341017.2
y
byEInxL
βξ
=
![Page 21: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/21.jpg)
Accelerator Systems Division
PEP-II Parameters for 3.1 GeV x 9.0 GeV
Parameter Units DesignApril 2008
Best2008
Potential
I+ mA 2140 3210 3700
I- mA 750 2070 2200Number bunches 1658 1722 1740
βy* mm 15-25 9-10 8.5
Bunch length mm 15 11-12 9
ξy 0.03 0.05-0.06 0.07
Luminosity x1033 3 12 20Int lumi / day pb-1 130 911 1300
7 times design4 times design
![Page 22: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/22.jpg)
Accelerator Systems Division
Running before Trickle (Continuous) Injection
![Page 23: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/23.jpg)
Accelerator Systems Division
Continuous Injection for PEP-II
![Page 24: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/24.jpg)
Accelerator Systems Division
PEP-II RF Cavity
Early design and testing at LBL.
High power production cells.
Fully fitted cavity units with HOM dampers.
![Page 25: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/25.jpg)
Accelerator Systems Division
B-Factory RF Klystrons (1.2 MW)
![Page 26: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/26.jpg)
Accelerator Systems Division
Optimal klystron operating points for stable beams
HER klystron Power = 0.98 MW
LER klystron Power = 1.01 MW
Cavity powers=HER: 285 kWLER: 372 kW
![Page 27: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/27.jpg)
Accelerator Systems Division
Bunch-by-bunch feedback systems (John Fox: Wed)
Frascati longitudinal kicker LBL transverse kicker
![Page 28: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/28.jpg)
Accelerator Systems Division
LER and HER RF Stability Limits
![Page 29: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/29.jpg)
Accelerator Systems Division
Close up of tile and RF seal damage
HOM damage on RF seals
HOM damage on absorbers
![Page 30: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/30.jpg)
Accelerator Systems Division
HER blows up in 14 msec
Streak cameraTiming plots
Bunch arrivaltime
![Page 31: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/31.jpg)
Accelerator Systems Division
HOM Absorbing Bellows
HOM tiles
Shield fingers
![Page 32: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/32.jpg)
Accelerator Systems Division
Final sliding bellows solution
The new MKIII bellows
![Page 33: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/33.jpg)
Accelerator Systems Division
Luminosity drop in “ long” mini-trains from ECI Solenoids
![Page 34: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/34.jpg)
Accelerator Systems Division
Lower βy* to increase luminosity
Final location
![Page 35: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/35.jpg)
Accelerator Systems Division
Beam-beam observations
Horizontal tune
Set fractional tunes (x/y) = 0.508/0.572
Luminosity
Corrected lattice opticsto design criteria for optimal emittances
Verticaltune
![Page 36: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/36.jpg)
Accelerator Systems Division
Beam-beam parameters
•By 4Extended
σy* = ~3.5-4.3 μm.
ξy= 0.05-0.06
ξx= 0.03-0.09
By 2
I- increases LER y size.I+ increases LER x size.I+ increases HER y size.
![Page 37: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/37.jpg)
Accelerator Systems Division
BaBar IP measurements reported online
• Luminous Region– centroids { x, y, z} – sizes { x, z } every 10 minutes– tilts { dx/dz, dy/dz }– dL/dz fit { Σz, β*y, zw, zc} every ~hour
• Boost Trajectory– mean { x’, y’ } every 10 minutes– spread { x’HER, y’HER } every 30 minutes
}
e- beam
e+ beamLuminosity measurements at 1Hz
![Page 38: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/38.jpg)
Accelerator Systems Division
IP Beam Size Measurements with BaBar
Bunch length
Collision longitudinallocation along train
Time histories
![Page 39: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/39.jpg)
Accelerator Systems Division
dL /dz
σyL
σy’B
PEPphase
advanceβ2
IP Beta Function Measurements (BaBar)
![Page 40: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/40.jpg)
Accelerator Systems Division
PEP-II General Accelerator “Achievements”
• Introduced beta-beats to help chromatic corrections near IR.
• First collider to continuously inject into a ring with the physics detector taking data.
• Installed 2 km of solenoids on the e+ LER ring to suppress the Electron Cloud Instability ECI.
• Held the overall luminosity record for several years. Now second to KEKB (1.2 vs 1.7 x 1034)
• Highest stored electron current (2.1 Amps)• Highest stored positron current (3.2 Amps)
![Page 41: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/41.jpg)
Accelerator Systems Division
![Page 42: The Last Year of PEP-II B-Factory Operation · The Last Year of PEP-II B-Factory Operation John Seeman for the PEP-II Team Stanford Linear Accelerator Center EPAC 2008 Genoa June](https://reader030.vdocuments.site/reader030/viewer/2022041121/5f35d0c758055d3c28353201/html5/thumbnails/42.jpg)
Accelerator Systems Division
PEP-II 1998-2008: Thanks to all!
•