Review of Recent Tevatron Operations

PAC 2007

Review of RecentTevatron Operations

Ron Moore

Fermilab – Tevatron Dept.

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


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)

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kly

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ted

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min

osi

ty (

pb-1

)

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3500

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ted

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pb

-1)

Weekly Integrated Luminosity

Run Integrated Luminosity> 1.5 fb-1 since

June 2006


Tevatron Run 2 Peak Luminosities

Recycler-only pbars & 28 cm β*


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!


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)


Beam Intensities at Start of HEP

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4500 4700 4900 5100 5300 5500

Store #

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ar

Inte

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ity

[E

9]

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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


Proton Inefficiency @ 150 GeV

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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


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


Better Lifetime More Delivered Luminosity

Normalized Lumi Integral / 24 hr vs Initial Luminosity

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Initial Luminosity [1030 cm-2 s-1]

Lu

mi

Inte

gra

l /

Init

ial

Lu

mi

[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


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


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)


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


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.


Luminosity Projections with Updated Model Scenarios

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9/29/03 9/29/04 9/30/05 10/1/06 10/2/07 10/2/08 10/3/09

Date

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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


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!


FY07 Tevatron Performance

Oct 1 → June 24

E4 cryo vacuum

A18 vacuum

leak

D32-5 failurefeeder 46B

fault


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!


Documents

Review of Recent Tevatron Operations