Review of Recent Tevatron Operations
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Transcript of Review of Recent Tevatron Operations
PAC 2007R. Moore - FNAL 2
Overview
• Tevatron
– 1 km radius superconducting synchrotron at 980 GeV beam energy
– Tevatron 36×36 proton-antiproton collisions to CDF & D0 experiments
– 3 trains of 12 bunches each with 396 ns separation
– Protons and antiprotons circulate in single beam pipe
• Electrostatic separators keep beams apart except where/when desired
• Beam-beam interactions (head-on & long range) play major role
PAC 2007R. Moore - FNAL 3
Tevatron Delivered Luminosity
0
5
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5 20 35 50 65 80 95 110 125 140 155 170 185 200 215 230 245 260 275 290 305 320Week #
(Week 1 starts 03/05/01)
Wee
kly
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ted
Lu
min
osi
ty (
pb-1
)
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3500
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-1)
Weekly Integrated Luminosity
Run Integrated Luminosity> 1.5 fb-1 since
June 2006
PAC 2007R. Moore - FNAL 5
2006 Tevatron Shutdown Tasks
• Fixed known cold leaks in E2, A3, B4; replace failed dipole in F4
• Installed 2 new separators (B48, A17), replace 3 separators (A49)
• Completed reshimming on remaining 228 dipoles
• Replaced all ≈1200 helium relief valves (Kautzky) on magnets
• Repaired TEL-1 and installed TEL-2 (electron lenses)
• Pulled cables for new sextupole circuits (2nd order chromaticity correction)
• Unrolled quads in A3 (~10 mrad); unroll ~60 magnets with small rolls
• Completed IPM detector installation
• Completed ring-wide hydrostatic level sensor installation
• Many smaller tasks, lots of maintenance…
• Tevatron Run II upgrades effectively complete!
PAC 2007R. Moore - FNAL 6
Highlights since 2006 shutdown…
• Record delivered luminosity / week 24.4 → 44.9 pb-1
• Record peak luminosity 180 → 292 1030 cm-2 s-1
• Delivered > 1.5 fb-1 to CDF and D0 (Run 2 total delivered now > 3 fb-1)
• More antiprotons with smaller emittances to HEP
– Thanks to Antiproton Source and Recycler
– See K. Gollwitzer’s talk tomorrow afternoon (WEZAKIO1)
• More protons to HEP
– Injecting ≈10% more protons
– Better lifetime @ 150 GeV from new helical orbit, reduced beam-beam
• Improved luminosity lifetime
– Additional separators increase separation (up to 20% at parasitic crossings)
– Beam-beam effects reduced
• Commissioned TEL-2 and demonstrated beam-beam compensation on protons
– See V. Shiltsev’s talk later this session (TUOCKI04)
PAC 2007R. Moore - FNAL 7
Beam Intensities at Start of HEP
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4500
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5500
4500 4700 4900 5100 5300 5500
Store #
Pb
ar
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ity
[E
9]
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6000
7000
8000
9000
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11000
Pro
ton
Inte
ns
ity
[E
9]
Pbar
Proton
Beam Intensities in HEP Stores
9500 E9 ≈ 264 E9 / bunch3000 E9 ≈ 83 E9 / bunch
2006
shu
tdow
n
PAC 2007R. Moore - FNAL 8
Proton Inefficiency @ 150 GeV
0
5
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500 1000 1500 2000 2500 3000 3500 4000
Pbar Intensity @ Injection [109]
Pro
ton
Ine
ffic
ien
cy
[%
]
Dec 04 - Feb 06
Jun 06 -
Improved Proton Efficiency vs Pbar Intensity
New injection helix increased separation between beams
reduced beam-beam effects
PAC 2007R. Moore - FNAL 9
Larger Separation with New Collision Helix
• Installed 2 additional separators during 2006 shutdown
• Luminosity lifetime improved ~20% compared to pre-shutdown – Increased integrated luminosity per store (for similar luminosities and duration)
blue – old red – present
Distance from B0 [m]
Beam
sep
ara
tion
in
σ
PAC 2007R. Moore - FNAL 10
Better Lifetime More Delivered Luminosity
Normalized Lumi Integral / 24 hr vs Initial Luminosity
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10
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0 50 100 150 200 250 300
Initial Luminosity [1030 cm-2 s-1]
Lu
mi
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l /
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ial
Lu
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[n
b-1
per
24
hr
/ 10
30 c
m-2
s-1
] Dec 04 - Feb 06
Jun 06 -
Based on luminosity lifetime fits and adjusting to 24 hour store
duration
PAC 2007R. Moore - FNAL 11
Beam Lifetimes during HEP
• Pbar lifetime dominated by luminosity – good
• Most protons lost in non-luminous processes – not so good
– Head-on beam-beam effects from smaller emittance pbars on protons
Luminosity[μb-1/s]
Pbar Lifetime
/ ExpectedLifetime from
Luminosity
Store 5245
Proton Lifetime
/ ExpectedLifetime from
Luminosity
1
0.75
0.5
0.25
0
300
225
150
75
0
PAC 2007R. Moore - FNAL 12
Store 5245 – Comparison to Model w/o Beam-Beam
Initial Lumi = 286 μb-1/s
~10% luminosity loss from beam-beam
effects
Luminosity IntegralModelData
See A. Valishev’s talk later this sesssion
(TUOCKI03)
PAC 2007R. Moore - FNAL 13
Reliability
• Over 280 HEP stores since June 2006 – 75% terminated intentionally
– Slightly better than the 72% Run 2 historical average
– Causes: power supplies ≈ 24%, cryo ≈ 11%, Mother Nature ≈ 10%, controls
≈ 9% , separators ≈ 7%
• Averaging ≈105 HEP store hours per week since October 2006
– Includes few weeks of downtime to repair failed Tevatron components
– Weeks of 130 store hours not uncommon
• Reliability
– Replaced all ≈1200 LHe Kautzky valves (cause of 2 FY06 dipole failures)
– Modifying quench protection system to allow faster beam aborts
– Cog pbars out of abort gap for acceleration – prevent needless quenches
PAC 2007R. Moore - FNAL 14
Looking Ahead in Tevatron
• Implement 2nd order chromaticity correction @ low β – in progress
• Simulations show improved lifetimes during HEP
• Also prerequisite to pursue possible new working point near ½ integer
• See A. Valishev poster (FRPMS015)
• Pursue other minor improvements (few % each) – they all add up!
• Scrape (higher intensity) protons @ 150 GeV
• Can reduce losses up ramp and through squeeze? Need to resume
• Investigating new cogging between antiproton injections
• Reduce beam-beam effects by changing locations of long-range crossings
• Use TELs (electron lenses) on protons for beam-beam compensation
• Raise tunes of individual bunches away from resonance to improve lifetime
• Better helices, improved transfer line matching, faster shot-setups, etc.
PAC 2007R. Moore - FNAL 15
Luminosity Projections with Updated Model Scenarios
0
1
2
3
4
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6
7
8
9
10
9/29/03 9/29/04 9/30/05 10/1/06 10/2/07 10/2/08 10/3/09
Date
Inte
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ted
Lu
min
osi
ty (
fb-1)
30mA/hr
25mA/hr
20mA/hr
15mA/hrupdated model scenarios 1 to 4
Goal = 8 fb-1
Peak Pbar Stacking Rate in Accumulator
Only ≈1 fb-1 spread in totalWe’re in this area now
3 fb-1
≈23 mA/hrJune ‘07
PAC 2007R. Moore - FNAL 16
Summary
• Tevatron luminosity made great progress over past year
– Doubled the delivered luminosity to > 3 fb-1
– Higher antiproton intensities with smaller emittances
– Improved luminosity lifetime from increased separation
• Tevatron upgrades complete, still reaping benefits
– Continue pursuing smaller operational improvements
• On track for 6-7 fb-1 total through October 2009
– 8 fb-1 is still the goal
– Need increased antiproton stacking rates for higher luminosity
• Make the most of the Tevatron before the end of Run 2!
PAC 2007R. Moore - FNAL 17
FY07 Tevatron Performance
Oct 1 → June 24
E4 cryo vacuum
A18 vacuum
leak
D32-5 failurefeeder 46B
fault
PAC 2007R. Moore - FNAL 18
Magnet Motion / Orbit Stabilization
V. Ranjbar
Orbit stabilization ONE11 vert BPM [mm]
F17 horz BPM [mm]
D0 proton halo [Hz]
Proton vert tune
C4Q4 roll [μrad]
C4Q4 pitch [μrad]
Proton intensity [E9]
Store 4402
New BPM electronics help us see this motion!