W. Kozanecki BBBTF meeting, 28(27) Apr 04

Recent PEP-II/BaBar Operational ParametersRecent PEP-II/BaBar Operational Parameters

Beam currents, luminosity, bunch patternBeam currents, luminosity, bunch pattern

Typical backgroundsTypical backgrounds integrated dose

beam aborts

stored-beam backgrounds

trickle backgrounds

CollimationCollimation

Vacuum historyVacuum history

Heating issuesHeating issues

W. Kozanecki, CEA-Saclay

W. Kozanecki BBBTF meeting, 28(27) Apr 04

Run 4 Beam-current & Luminosity HistoryRun 4 Beam-current & Luminosity History

LER total current

HER total current

Luminosity

W. Kozanecki BBBTF meeting, 28(27) Apr 04

W. Kozanecki BBBTF meeting, 28(27) Apr 04

W. Kozanecki BBBTF meeting, 28(27) Apr 04

IP Parameter Design Peak performance Apr 04

C-M energy (GeV) (e+: 3.1 ; e-: 9.0) 10.58 10.58Crossing angle (mrad) 0.0 < 1.0Luminosity (x 1033/cm2/s) 3.00 8.33

Number of bunches 1658 1549 LER current (mA, e+) 2146 2230 HER current (mA, e-) 750 1380 LER/HER current ratio 2.9/1 1.6/1

y*/x* (cm/cm) 1.5 / 50 1.1 / 48+, 1.1 / 28-Emittance (nm-rad) (y/x) 1.5 / 49 1.0 / 30+, 1.3 / 59-

LER tunes (x/y) 38.64 / 36.57 38.52 / 36.56HER tunes (x/y) 24.62 / 23.64 24.52 / 23.62Beam-beam parameter (vertical +/-) 0.03 0.067 / 0.046Beam-beam parameter (horizontal +/-) 0.03 0.086 / 0.032

PEP- II Collision Parameters (Apr 04)PEP- II Collision Parameters (Apr 04)J. Seeman, Apr 04

W. Kozanecki BBBTF meeting, 28(27) Apr 04

Run-4 radiation dose-rate historyRun-4 radiation dose-rate history

HER trickle starts

HER trickle starts

Outgassing storms

W. Kozanecki BBBTF meeting, 28(27) Apr 04

Integrated-dose historyIntegrated-dose history

W. Kozanecki BBBTF meeting, 28(27) Apr 04

Stable-beam “genuine” radiation aborts: Stable-beam “genuine” radiation aborts: 0.9 / day

~ 60% of these may actually be sympathetic

““Genuine” injection aborts: 0.4 / dayGenuine” injection aborts: 0.4 / day

...to be compared to an average of 7 aborts/day from all sources...to be compared to an average of 7 aborts/day from all sources

W. Kozanecki BBBTF meeting, 28(27) Apr 04

Stored-beam background historyStored-beam background history

SVT ocp’cy @ = (HEB-sensitive)

SVT ocp’cy @ = (LEB-sensitive)

20% 20%

Normalized DCH current

I DC

H, m

srd

/pre

d

10%

W. Kozanecki BBBTF meeting, 28(27) Apr 04

Trickle-injection backgroundTrickle-injection background

The background generated by The background generated by the trickle injection is the trickle injection is concentrated in a narrow time concentrated in a narrow time window corresponding to window corresponding to revolutions of the injected revolutions of the injected bunch.bunch.

BABAR vetoes BABAR vetoes this windowthis window during data taking to avoid high during data taking to avoid high dead timedead time

BABAR rejects a larger region at BABAR rejects a larger region at the analysis phase to guarantee the analysis phase to guarantee good data quality. good data quality.

The total loss is around 1.5%The total loss is around 1.5%

Veto windowsVeto windows

W. Kozanecki BBBTF meeting, 28(27) Apr 04

LER collimatorsLER collimators PR04: 4 fixed: x,y,x,y (orbit bumps)

horizontal collimators useful to reduce beam-beam background.

vertical collimators sometimes help with the LER trickle backgrounds.

PR02: 2 adjustables (x) a major source of HOM heating.

can help with beam-beam tails in some subdetectors, but at the cost of swamping the IFR (and sometimes the DCH) with secondaries, so we use them very little move them elsewhere ?

HER collimatorsHER collimators PR12: 5 fixed: x,y,x,y,E

occasionally useful trickle, beam-beam

PR02: 2 adjustable (x) not useful

CollimationCollimation

HER collimators

LER collimators

W. Kozanecki BBBTF meeting, 28(27) Apr 04

Ring-averaged presssure (Ring-averaged presssure (Jul 2000, Jul 2000, from inverse lifetime)from inverse lifetime)

LER lifetime

0

100

200

300

400

500

600

700

0 500 1000 1500

LER current (mA)

Lif

eti

me (

min

s)

No HER

Average LER pressure (from inv. lifetime)

0

1

2

3

4

5

6

0 500 1000 1500

LER current (mA)

<P

_LER

> (

nT N

2-e

q)

Msrd (LER only)

Fitted

Fitted pressure:p_b = 1.1 nT

p_d = 2.9 nT/A(summer 2000)

HER lifetime

0

200

400

600

800

1000

1200

1400

1600

1800

0 200 400 600 800HER current (mA)

Lif

eti

me (

min

s)

No LER

HER-averaged pressure (from inv. lifetime)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0 200 400 600 800HER current (mA)

<P

_HER

> (

nT N

2-e

q.)

Data

Fitted

Fitted pressure:p_b = 0.84 nTp_d = 1.1 nT/A

(summer 2000)

2004: <p> < 0.9 nT @ 1 A

W. Kozanecki BBBTF meeting, 28(27) Apr 04

Near-IR vacuum historyNear-IR vacuum history

LER current Incoming e+ (7 m

from IP, LEB-sensitive )

Outgoing e+ (7 m from IP, L+HEB-sensitive )

Incoming e- (17 m from IP, HEB-sensitive )

W. Kozanecki BBBTF meeting, 28(27) Apr 04

Thermal time constants: a problem!Thermal time constants: a problem!

VGCC2187 (HER sensitive)

BW diamond [+ BBR dead time] (HEB sensitive)

VGCC3027 (incoming

LEB)

BE diamond (LEB sensitive)

LER current

12 hours

W. Kozanecki BBBTF meeting, 28(27) Apr 04

LER current 2.2 A 3027 = 268°F 3044 = 453°F

3053 = 425°F 3081 = 724°F

LER NEG temperatures

#1 #2

#3 #4

W. Kozanecki BBBTF meeting, 28(27) Apr 04

IIR Heating Issues - OverviewR Heating Issues - Overview

HOM Heating HOM Heating Vertex Bellows Cooling Addition 2002 is working well Q1/Q2 Bellows

Larger HOM absorbers in 2002, Cooling and monitoring improved. Will need to improve HOM/Power capability - now 10 KW

Synchrotron Radiation and Orbit ConstraintsSynchrotron Radiation and Orbit Constraints Require LEB aimed at Luminosity Monitor IP angles constrained by backgrounds LEB B1 Fan Hits LEB Leg of Q2 Crotch and Q4 chamber

May be cause of magnet motion (~20 microns). HEB – B1 fan aimed at High Power Dump must miss Q5R chamber flange

Vacuum and BackgroundsVacuum and Backgrounds HOM Heating of NEG and Increased Backgrounds

W. Kozanecki BBBTF meeting, 28(27) Apr 04

Spare slidesSpare slides

W. Kozanecki BBBTF meeting, 28(27) Apr 04

Near IRNear IR