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Luminosity Measurement Activities

M. Corcoran and G. Snow for the Luminosity Group Conveners Meeting / 3 August 2007

Outline• Detector: Radiation damage and recovery

• Luminosity database• Corrections implemented in production database• Luminosity database access speed-up• Stage3 and database comparisons• Database verification and clean-up

• Run IIb constant status

2since beginning of Run IIb

From May 18 conveners talk:Light output of LM scintillatorsis steadily deteriorating

Yugi Enari

constant, if no radiation damage

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• Annealing effect– From 11th July,13:00, nitrogen purge for LM was replaced with dry

air– Clearly see annealing effect of the oxygen, all scintillators similar– The recovery now looks saturated– LM scintillators will be replaced during this shutdown

2007.7.11

200.7.26

Yugi Enari

Oxygen Annealing a Success

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• D periodically takes special runs triggering on single muons measured in the forward muon detectors for monitoring purposes

• A pseudo cross-section called the “muon yield (Y)” is calculated:

Number of reconstructed muons Y = Integrated luminosity in special run

• An uncertainty of about 1% (stat + syst) is estimated for the numerator in each muon yield calculation

• The muon yields can potentially reveal instabilities in the luminosity measurement

• The following plots show normalized yields defined as

Ynorm = Y / (mean value)

Forward Muon Special Runs

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• Forward muon yields show stability within 1% during Run IIb

Ynorm Normalizedmuon yield

Normalized muon yields, Run IIb

0.9

0.95

1

1.05

1.1

7/2/2006 8/21/2006 10/10/2006 11/29/2006 1/18/2007 3/9/2007 4/28/2007 6/17/2007

Date

1%

July 112006

June 242007

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• Special runs taken during 2 stores in late 2006• November 29 (Linitial = 105E30) and December 12 (Linitial = 229E30)

• Note absence of instantaneous luminosity dependence

Ynorm Normalizedmuon yield

Instantaneous L

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Final corrections implemented in production database (Delivered L only here)

Period A Period B Period C

Period D Periods E + E’ Period F

Correction = 1.00

Plotted: Line = Correction function vs. delivered instantaneous luminosity Points = Corrected luminosity / Uncorrected luminosity vs. uncorrected delivered“Outlying LBNs” (showing greater L than ever delivered for a given period)are understood as stemming from unusable, non-physics runs

E. Gallas, K. DeVaughan

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Thanks to Elizabeth Gallas

A thanks to Elizabeth Gallas was posted in D0Newson July 30 for her work implementing the correctionsin the database.

Hours of tireless volunteer work over the last few months.

Real work ended June 15, but she is still plugged in.

My machine shop is preparing a gift – desk ornament madefrom Run IIa LM scintillators mounted on an engravedbase. (Don’t tell her!)

Igor Mandrichenko has taken over DB offline maintenanceand has inherited DB run report code from Ana in Brazil.

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New lm_access tools for retrieving database luminosity

LBNs/secondretrieved

Stage3retrieval about

a factor of2 faster than

database

• Luiz Mundim’s (+ others) new tools to speed retrieval of luminosity information from the database by a factor of ~100 are essentially ready to go. Example: Run IIa data set – 2.5 hours Stage3, 5 hours database for 1 trigger.• Observation: Database retrieval depends on client machine (5 hours above using DB server, 3.75 hours on Luiz’s Clued0 box.)• Luiz also testing multiple users hitting DB – not a big issue due to low usage.• Next step for these tools: Run on development instance, then ready for production instance. (S. White)• Release expected when next two steps are complete (about 1 month).

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Database/Stage3 comparison status

V. Malyshev has done a thorough comparison of the recordedluminosity for the entire Run II data sample, using groups ofruns.

Our general aim: investigate discrepancies greater than 0.5%.Examples:Run range: 221694-224486 DB: 58.6526pb-1 Stage3: 58.6654pb-1

DB 0.02% smaller than Stage3Run range: 226073-229706 DB: 211.547pb-1 Stage3: 211.271pb-1

DB 0.13% larger than Stage3Run range: 229707-230270 DB: 94.6721pb-1 Stage3: 82.9074pb-1

DB 14.2% larger than Stage3 – tracked down to missing Stage3 files

• Luiz has made a new script to do detailed LBN by LBN comparisons so we can understand both large and very small differences.• Work to be done by Luiz, Marj, Greg, Kayle since Vladimir will be consumed by shutdown work.• This will also shed light on the last issue ……………….

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Database verification and clean-up

J. Linnemann and S. White are investigating the databasecontent, entry-by-entry.

The DB contains many more error and status messages/flagscompared to the stage3 LBN-level status flagsJim: DB has 1.1 billion trigger status messages.Example: “Such-and-such trigger did not fire during this LBN’sduration”.

Lm_access only checks LBN-level status messages to decide whetherto include or throw out an LBN in an integrated lumi calculation.

Tasks: • Determine whether any important status messages in DB are missed by lm_access, whether they are redundant, useless, etc.• Decide fate of additional status flags in DB – delete, clean up, quit writing them, pay attention to them, etc.• One month time scale.

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Run IIb Normalization Constant Do-List (M. Corcoran, M. Prewitt)

1. Get the material file updated and put into GEANT. (Done, see next)

2. Tune up the detector response MC. (In progress, see next)

3. Take zero bias data to make the multiplicity distribution in the data. (Done, see next.)

4. Generate MC samples of non-diffractive, single-diffractive, and double-diffractive to get the efficiencies of each process, using the version of Pythia used for the RunIIa constant.

5. Using the non-diffractive fraction from RunIIa as a starting point, compare the multiplicity distributions in data and Monte Carlo.

6. Depending on how well data and Monte Carlo agree in (5), vary the material model in the Monte Carlo over a reasonable range. Generate MC samples with at least two different values of detector material.

7. Fit for the non-diffractive fraction using the 2-bin fit method, varying the assumed luminosity (which changes the multiple interactions) over a reasonable range. Do these fits for the different models of detector material to confirm that the two-bin fit is insensitive to the material description.

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Beam Pipe Geometry ChangesRun 2b Beam Pipe

Color Component Name Material Diameter (in) Z initial (in) Z final (in) Length (in)

L. Blue Beam Tube Beryllium 1.160 0.000 34.556 34.556Brown Stub End 304-SST 1.000 34.556 36.000 1.444Black Gasket Torlon 1.000 36.000 36.060 0.060Brown Stub End 304-SST 1.000 36.060 37.685 1.625Yellow Beam Tube 321-SST 1.500 37.685 38.034 0.349Grey Inner Bellows Assembly 347 & 304 SST 1.500 38.034 39.604 1.570Yellow Beam Tube 321-SST 1.500 39.604 46.674 7.070Purple Adapter 304-SST 1.500 46.674 48.487 1.813Black Gasket Aluminum 1.500 48.487 48.527 0.040Purple Adapter 304-SST 1.500 48.527 50.152 1.625Grey Outer Bellows Assembly 347 & 304 SST 1.500 50.152 52.892 2.740

Green Inner Flange 1.738 35.486 36.574 1.088Green Outer Flange 2.238 47.963 49.051 1.088Red Inner Bellows 347-SST 2.250 38.469 39.169 0.700Red Outer Bellows 347-SST 2.250 50.587 52.457 1.870D. Blue Bellows Cover Aluminum 2.750 50.152 52.809 2.657

Around Beam Line

In Beam Line

z=0 z=30 z=60 z=90 z=120

LM here

Example: new inner flange

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GEANT drawing with IIb material

Latestaddition:These supportstructures

Material description now as good as we’re likely to get it. Materialwill be varied in this study anyway to assess dependence.

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Data and Monte Carlo LM pulse height distributions

Michelle Prewitt

DataZero-bias run at 28E30

taken July 13, 2007Sum of all 48 LM detectors

pC pC

Monte CarloNon-diffractive events only

No multiple interaction overlaySum of all 48 LM detectors

From the pre-scaled zero-bias events taken during normal physicsruns, we will be able to collect sets of events from very low tovery high instantaneous luminosity for comparison to MC multiplicitydistributions with different multiple interaction models.

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Run IIb Normalization Constant Do-List (M. Corcoran, M. Prewitt)

1. Get the material file updated and put into GEANT. (Done, see next)

2. Tune up the detector response MC. (In progress, see next)

3. Take zero bias data to make the multiplicity distribution in the data. (Done, see next.)

4. Generate MC samples of non-diffractive, single-diffractive, and double-diffractive to get the efficiencies of each process, using the version of Pythia used for the RunIIa constant.

5. Using the non-diffractive fraction from RunIIa as a starting point, compare the multiplicity distributions in data and Monte Carlo.

6. Depending on how well data and Monte Carlo agree in (5), vary the material model in the Monte Carlo over a reasonable range. Generate MC samples with at least two different values of detector material.

7. Fit for the non-diffractive fraction using the 2-bin fit method, varying the assumed luminosity (which changes the multiple interactions) over a reasonable range. Do these fits for the different models of detector material to confirm that the two-bin fit is insensitive to the material description.

Things will move more quickly now. Michelle at FNAL through the end ofAugust, will continue at Rice Univ. along with classes and teaching. Thisproject constitutes her Masters Thesis.

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Backup Slides

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The Luminosity Database “Schema”

L1 and recorded

Delivered Exposed

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Period Dates Run Range

A Beginning RunII

(4/20/2002) to Fall 04 shutdown (8/23/2004)

151817 to 196584

B 12/7/2004 to 12/19/2004

201537 to 202111

C 12/19/2004 to 3/17/2005

202152 to 204805

D 3/17/2005 to 10/20/2005

204806 to 211213

E 10/20/2005 to Spring 2006 shutdown

(2/22/2006)

211214 to 215670

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Curves indicatemax Linst for each

period

Back-propagation correction functions

Period EPeriod D

Period C

Period BPeriod A

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Period Correction Function

A fA(L) = fB(L) 1.026 (0.9839/0.9890)

B fB(L) = fC(L) [1.0 + (7.0410-4)L + (8.3710-6)L2 - (1.88×10-7)L3](0.9890/0.9904)

C fC(L) = fD(L) [0.998 exp[(1.50 10-5) L2] ](0.9904/0.9959)

D fD(L) = fE(L) [ 1.017 – (9.35 10-4) L + (7.41 10-6) L2]0.9959

E fE(L) = 1.125 [1.0 - (1.7110-4)L + (2.4910-7)L2]

Table of correction functions(L is uncorrected, in units of

E30)

Period E’ is defined as the period from the beginning of Run IIbthrough September 29, 2007, when new constant went online, andPeriod E corrections are applied (to be confirmed with IIb constant)

Period F starts with September 30, 2007, and correction is 1.00(to be confirmed with IIb constant)