f uec - 6 oct 06 recent fnal collider operations ron moore fermilab – tevatron dept

UEC - 6 Oct 06

f Recent FNAL Collider Operations

Ron Moore

Fermilab – Tevatron Dept.

UEC - 6 Oct 06R. Moore - FNAL 2

f Hooray for record luminosities! How’d you do it?

• Notable achievements since the long shutdown ended

– Delivered lumi / week = 33.3 pb-1

– Delivered lumi from Aug 28-Sep 3 ≈ 119 pb-1

– Peak luminosity = 229 1030 cm-2 s-1 (store 4964 average, before D0 correction)

– Record # pbars at start HEP ≈ 2870 109

• Contents– Ingredients to record running

• Tevatron: efficiencies, luminosity lifetime

• Recycler: new working point smaller emittances

• Pbar Source: near record stacking rates

• Proton Source: near record beam intensity

• Reliability (and little luck)

– FY07 Plan


f Where have we been? FY06 Outcome

Tevatron B1 Repairs/Start-up

Tevatron A4 Warm-up/

Repairs

FY06Shutdown


f Run II Peak Luminosities


f Luminosity Formula

• N = bunch intensity, f = collision frequency

• ε = transverse emittance (size), σz = bunch length

• H = “hour glass” factor (<1, accounts for beam size over finite bunch length)

Increasing the Luminosity

• Decrease β* (new 28 cm β* lattice in Sep 05)

• Increase Na and/or decrease εa from Recycler + electron cooling

• Increase Np

)()(2

**

z

ap

ap HNfN

L


f Increasing Beam Intensities

Beam Intensities at Start of HEP

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

4000 4200 4400 4600 4800 5000

Store #

Pb

ar

Inte

ns

ity

[E

9]

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

Pro

ton

Inte

ns

ity

[E

9]

Pbar

Proton

10000 E9 278 E9 / bunch 2700 E9 75 E9 / bunch


f Reduced Tevatron Beam Loss @ 150 GeV

Bunched Beam Inefficiency @ 150 GeV

-5

0

5

10

15

20

25

30

4000 4200 4400 4600 4800 5000

Store #

Ine

ffic

ien

cy

[%

]

Pbar

Proton


f Reduced Beam-Beam Effects @ 150 GeV

Proton Inefficiency @ 150 GeV

0

5

10

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30

500 1000 1500 2000 2500 3000 3500

Pbar Intensity @ Injection [E9]

Pro

ton

Inef

ficie

ncy

[%

]

Dec 04 - Feb 06

Jun 06 -

• Protons suffered from higher pbar intensities

• New helix (separator voltages) increased separation, especially at worst crossing point


f• Long-range beam-beam effects degrade luminosity lifetime + integral

– Nearest parasitic crossings (≈59 m from IPs) especially bad

• During shutdown, additional separators installed to increase separation– More separation reduced beam-beam effects

– ~20% increase @ upstream IP

– Not as much @ downstream IP

• Luminosity lifetime improved ~20% compared to pre-shutdown running– Increased integrated luminosity per store (for given store length)

Tevatron Luminosity Lifetimes


f Better Lifetime More Delivered Luminosity

Normalized Lumi Integral / 24 hr vs Initial Luminosity

0

1000

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7000

8000

0 50 100 150 200 250

Initial Luminosity [1030 cm-2 s-1]

No

rmal

ized

Lu

mi

Inte

gra

l [n

b-1

per

24

hr]

Dec 04 - Feb 06

Jun 06 -

Based on luminosity lifetime fits and adjusting to 24 hour store duration


f Comparing HEP Stores to Model

• Luminosity evolution during

HEP now agrees better to

model without beam-beam

effects

• Most pbars lost during HEP

are burned in luminosity

– That’s good!

• Protons suffer more from

beam-beam effects

– Especially with smaller pbars

V. Lebedev


f New Recycler Working Point

• During HEP shot-setup, Recycler “momentum-mines” 9 parcels that become the 9 pbar transfers (4 bunches/transfer) shot to the Tevatron

• Poor lifetime and high transverse emittance growth rate in that state

• New tune working point reduced emittance growth rate (mid-August) Brighter (smaller emittance) pbars delivered to Tevatron

Higher instantaneous luminosity for same number of pbars

(Smaller emittances also improves pbar and proton efficiencies in Tevatron)

• Currently limiting max Recycler pbar “stash” to 400 1010

• Increase as experience and pbar stacking rate allow


f Pbar Stacking

0

5

10

15

20

25

7/1/2005 8/20/2005 10/9/2005 11/28/2005

1/17/2006 3/8/2006 4/27/2006 6/16/2006 8/5/2006 9/24/2006

Ave

rage

Sta

ckin

g R

ate

(E

10/h

r)

0

1000

2000

3000

4000

5000

Antip

roto

ns

x 101

0

Average Stacking rate

Pbars delivered•Started slowly after shutdown, partly due to Booster proton output

•Ramped up to record performance (20.5 mA / hr peak yesterday)

•Increasing stacking still most direct route to higher Tev luminosities

Ave

rag

e S

tack

ing

Rat

e [

101

0 m

A /

hr

]

Pba

rs D

eliv

ered

[1

010

]


f Protons on Pbar TargetNow > 8 1012

protons / pulse on target


f Reliability

Motherhood statement: You can’t integrate luminosity if you aren’t running…

Mother Nature statement: How’d you like Monday’s storm? I won that round…

5 store running averages


f Where do we go from here? The FY07 Plan

8 week shutdown

~2x existing dataset

Ramp up to48 pb-1/ week


f FY07 Plan for Peak Luminosity


f Summary

• Record running thanks to performance and reliability of all machines

– More protons on pbar target (Linac / Booster / Main Injector)

– Near record pbar stacking rates (Debuncher / Accumulator)

– Smaller pbar emittances from Recycler

– More beam to HEP and improved luminosity lifetime in Tevatron

– Good reliability and luck to avoid (most of) Mother Nature’s wrath

• Current Tevatron Records

– Delivered luminosity / week = 33.3 pb-1

– Peak luminosity = 229 1030 cm-2 s-1

• FY07 plan

– Deliver ≈ 1800 pb-1 at up to 48 pb-1/ week

– Reach peak luminosity 3.2 1030 cm-2 s-1

– 8 week shutdown during summer


f

Accelerator Highest Energy

Cockroft Walton 750 keV

Linac 400 Mev

Booster 8 GeV

Main injector 150 GeV

TEVATRON 980 GeV

NuMI (120 GeV)MiniBoone

(8 GeV)

P1 Line

A1 Line


fCollider Run II Integrated Luminosity

0

5

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25

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35

5 20 35 50 65 80 95 110 125 140 155 170 185 200 215 230 245 260 275 290

Week #(Week 1 starts 03/05/01)

Wee

kly

In

teg

rate

d L

um

ino

sit

y (

pb

-1)

0

400

800

1200

1600

2000

Ru

n In

teg

rate

d L

um

ino

sity

(p

b-1

)

Weekly Integrated Luminosity Run Integrated Luminosity


f FY07 Plan for Weekly Integrated Lumi


f

0

1

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10S

ep-0

3

Sep

-04

Sep

-05

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-06

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-07

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-08

Oct

-09

Date

Inte

grat

ed L

umin

osity

(fb

-1) 30mA/hr

25mA/hr

20mA/hr

15mA/hr

Run II Luminosity Projections

Zero-Stack Pbar Stacking Rate Design

Now on this line

f uec - 6 oct 06 recent fnal collider operations ron moore fermilab – tevatron dept

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