Antonio Zoccoli RICH 2007 – Trieste 1 October 20, 2007 LUCID* - A Cherenkov tubes based detector for monitoring the ATLAS luminosity LUCID* - A Cherenkov

Antonio ZoccoliAntonio Zoccoli RICH 2007 – TriesteRICH 2007 – Trieste 11

October 20 , 2007October 20 , 2007

LUCID* - LUCID* - A Cherenkov tubes A Cherenkov tubes based detector for monitoring based detector for monitoring

the ATLAS luminositythe ATLAS luminosity

Antonio Zoccoli – University & INFN - BolognaAntonio Zoccoli – University & INFN - Bologna For the LUCID collaboration (Alberta, Bologna, For the LUCID collaboration (Alberta, Bologna,

CERN, LUND)CERN, LUND)



Detectors requirements Detectors requirements Test beam results & Rad. Hard. Test beam results & Rad. Hard.

MeasurementsMeasurements Detector design and installation Detector design and installation

strategystrategy Present status of the detector Present status of the detector ConclusionsConclusions

OutlineOutline

• Outline• Forward

ATLAS• LUCID the

basic concept

• Location • LUCID the

readout• Test beam

studies• LUCID: rad.

hard. tests• Installation

strategy• LUCID Design • LUCID under

construction• LUCID

assembled• The

alignment system

• LUCID: the electronics

• Installation• Conclusion



Forward detectors in AtlasForward detectors in Atlas



LUCID is an array of Cerenkov tubes (length ~1.5m) LUCID is an array of Cerenkov tubes (length ~1.5m) made of polished aluminium using C4F10 gas as a made of polished aluminium using C4F10 gas as a radiatorradiator

The Cerenkov threshold (10 MeV for e’s 2.8 GeV for The Cerenkov threshold (10 MeV for e’s 2.8 GeV for ’s) + the pointing of the tube to the IP suppresses ’s) + the pointing of the tube to the IP suppresses background from non-pointing soft secondaries and background from non-pointing soft secondaries and scattersscatters

It is possible to count multiple particles traversing the It is possible to count multiple particles traversing the length of the same tube (no Landau Fluctuations)length of the same tube (no Landau Fluctuations)

A good time resolution ( ~2ns) allows individual beam A good time resolution ( ~2ns) allows individual beam crossings to be studiedcrossings to be studied

This technique was first used at CDF (the CLC)This technique was first used at CDF (the CLC)

LUCID – The Basic ConceptLUCID – The Basic Concept

The Cerenkov light is The Cerenkov light is produced at ~3produced at ~3oo making ~ 3 reflectionsmaking ~ 3 reflectionsas it passes down the as it passes down the length of the tube length of the tube

• Forward ATLAS

• LUCID the basic concept





strategy• LUCID readout • LUCID under


assembled• The alignment

system• LUCID: the

electronics• Installation• Conclusion



Front face of each end LUCID is ~17m from the IPPHASE 1 6.0 > |η| > 5.6

The Location of LUCID The Location of LUCID • Forward

ATLAS• LUCID the

basic concept• Location • LUCID the




strategy• LUCID design • LUCID under







LUCID has to count the number of particles hitting the LUCID has to count the number of particles hitting the detector that are consistent with originating from the IPdetector that are consistent with originating from the IP

There is a linear relationship between the number of There is a linear relationship between the number of particles detected and the luminosityparticles detected and the luminosity

The detector has to cope to high radiation levels The detector has to cope to high radiation levels All All parts (especially PMTs) must be rad. hard.parts (especially PMTs) must be rad. hard.

Two readout schemes investigated and studied in beam Two readout schemes investigated and studied in beam tests:tests:

PMT directly coupled to the Cherenkov tubes (PMT directly coupled to the Cherenkov tubes (rad rad hard tests neededhard tests needed))

and fused-silica fibre readout to remote MaPMTs (and fused-silica fibre readout to remote MaPMTs (No No rad hard problemsrad hard problems))

LUCID – The readoutLUCID – The readout• Forward

ATLAS• LUCID the












Test Beam Studies - 1Test Beam Studies - 1

Test beam at DESY Test beam at DESY (electron beam) :(electron beam) :– Nov. `05, Nov. `05,

– Aug. `06,Aug. `06,

– Dec. `06.Dec. `06.

μμ = < = <# of # of photoelectrons> from photoelectrons> from spectra fitspectra fitμ

nn n

n 0

eS(x) μ G (Q , )

n!

Gas Vessel

Tubes read outS1 S3

S2

T1 T2

BEAM PMTPMT

MAPMT



Test Beam Studies – PMT readoutTest Beam Studies – PMT readout #Photoelectrons #Photoelectrons

using PMT using PMT readout:readout:– ~70 pe’s/tube~70 pe’s/tube from from

gas at 1 bargas at 1 bar

– ~50~50 pe’s/tubepe’s/tube from from PMT windowPMT window

– ~120 pe’s/tube~120 pe’s/tube TOTALTOTAL

P1

P0P2

Npe- (P1)~70

Npe- (P2)~120

Pressure scan: Pressure scan: #Photoelectrons#Photoelectrons vs gas pressurevs gas pressure



#Photoelectrons #Photoelectrons using fibre using fibre readout via readout via Winston cone to Winston cone to remote MaPMT, remote MaPMT, summing up summing up single fibre yieldssingle fibre yields– ~12-15 pe’s/tube ~12-15 pe’s/tube

at 1.25 barat 1.25 bar

Test Beam Studies – fibre readoutTest Beam Studies – fibre readout

Central fibres Lateral fibres

Middle fibres

• Forward ATLAS













Rad hard tests on PMT Rad hard tests on PMT HAMAMATSU R762:HAMAMATSU R762:– gammagamma: : 6060Co source, ECo source, EMM=1.22=1.22 MeV MeV

dose: (20dose: (20±1)MRad ±1)MRad 3 year LUCID phase 2 3 year LUCID phase 2– neutronneutron: ENEA-Casaccia reactor <E>: ENEA-Casaccia reactor <E>~100 KeV~100 KeV

dose: dose: ~5x10~5x103434 ncm ncm-2-2 1 year LUCID phase 2 1 year LUCID phase 2

LUCID: PMT rad. hard. testsLUCID: PMT rad. hard. tests

• Forward ATLAS










electronics• Installation• Conclusion No relevant effects for LUCID phase 1 No relevant effects for LUCID phase 1

(10 times less than phase 2)(10 times less than phase 2)

gammagamma

neutronneutron



PHASE 1 - Low lumi L < ~ 1033 cm-2 s-1 ends 2009Dominating sys Final goal ~4-5% + pp (CDF:~4% )

PHASE 2 – High lumi L ~ 1034 cm-2 s-1 after 2009Final goal ~ 2-3% +pp

New project approved. Two different detectors: New project approved. Two different detectors: phase 1 (low lumi) + phase 2 (high lumi)phase 1 (low lumi) + phase 2 (high lumi)

Main goal: end of construction in July 2007Main goal: end of construction in July 2007

LUCID review: installation strategyLUCID review: installation strategy



The Design Approved in JanuaryThe Design Approved in January

Fibre RO (4)

PMT RO(16)

Outer layer ~115 mm rad.Inner layer ~96 mm rad.

LUCID approved for installation in ATLAS in January 2007LUCID approved for installation in ATLAS in January 2007 LUCID construction completed in July 2007LUCID construction completed in July 2007

Mass = 22 KgVolume = 54 litres

20 Cerenkov Tubes each end

• Forward ATLAS













The main elements of LUCID produced during the The main elements of LUCID produced during the construction phase of LUCIDconstruction phase of LUCID

LUCID Under ConstructionLUCID Under Construction

Gas vessel Gas vessel componentscomponents

LUCID gas vessel under LUCID gas vessel under Pressure testPressure test

PMT Test FacilityPMT Test Facility

PMT holdersPMT holders Cerenkov tube Cerenkov tube manufacturemanufacture

Fibre-optic cable Fibre-optic cable manufacturemanufacture

IINN

BBOOLLOOGGNNAA

IINN

AALLBBEERRTTAA

• Forward ATLAS













LUCID was fully assembled at CERN by an Alberta-LUCID was fully assembled at CERN by an Alberta-Bologna-CERN-Lund team in July 2007Bologna-CERN-Lund team in July 2007

Test with the LUCID LED pulser system showed all Test with the LUCID LED pulser system showed all channels were functioning correctly.channels were functioning correctly.

LUCID Assembled LUCID Assembled • Forward

ATLAS• LUCID the












Alignment to a fraction of a degree to the beam axis requiredAlignment to a fraction of a degree to the beam axis required Test mounting of alignment system on 3Test mounting of alignment system on 3rdrd gas vessel in 10/07 gas vessel in 10/07

The Alignment SystemThe Alignment SystemRear alignment system Front alignment system

Mods to the VJ coneFor LUCID support& alignmentsystem

Alignment system piecesProduced at Alberta

• Forward ATLAS













The PMT readout is produced tested and installed (upper The PMT readout is produced tested and installed (upper photos)photos)

The MaPMT readout (lower photos) is in a advanced state of The MaPMT readout (lower photos) is in a advanced state of readiness. Final commissioning will start as soon as the MAROC3 readiness. Final commissioning will start as soon as the MAROC3 chip is available next springchip is available next spring

The main LUCID processor VME card (LUMAT) (trigger, data The main LUCID processor VME card (LUMAT) (trigger, data output, on-line lumi measure) is in an advanced state of design output, on-line lumi measure) is in an advanced state of design – estimated to be ready next spring– estimated to be ready next spring

LUCID ElectronicsLUCID Electronics

• Forward ATLAS













So far the move towards So far the move towards installation is on schedule installation is on schedule

After the final beam test, presently ongoing @ CERN, After the final beam test, presently ongoing @ CERN, we plan to move the LUCID modules into the cavern we plan to move the LUCID modules into the cavern and test connect them to the available services and test connect them to the available services

The final installation of LUCID in the ATLAS forward The final installation of LUCID in the ATLAS forward region is slated for the end of February 2008region is slated for the end of February 2008

Towards the Installation of LUCID Towards the Installation of LUCID

Connect Connect to theseto these

resourcesresources

• Forward ATLAS













The LUCID design approved at the ATLAS review in January The LUCID design approved at the ATLAS review in January 2007 has been successfully realized2007 has been successfully realized

LUCID was assembled in July 2007 according to schedule LUCID was assembled in July 2007 according to schedule The gas system, the cooling vessel and the alignment The gas system, the cooling vessel and the alignment

system have been designed and are being assembledsystem have been designed and are being assembled The electronics is in an advanced state of readiness and is The electronics is in an advanced state of readiness and is

envisaged to be completely available by Spring 2008envisaged to be completely available by Spring 2008 Extensive beam tests have been performed successfully at Extensive beam tests have been performed successfully at

DESY. A final test beam at CERN is ongoing, that will DESY. A final test beam at CERN is ongoing, that will enable us to calibrate the LUCID detector(s)enable us to calibrate the LUCID detector(s)

Rad. Hard. Studies have been carried out on the PMT to be Rad. Hard. Studies have been carried out on the PMT to be installed installed

The software necessary for the LUCID detector integration The software necessary for the LUCID detector integration in the general MC and for the luminosity monitor is moving in the general MC and for the luminosity monitor is moving on schedule on schedule

Remaining – important - detector studies (systematic Remaining – important - detector studies (systematic effects etc.) are in an advanced phaseeffects etc.) are in an advanced phase

We are progressing on schedule and will be ready for We are progressing on schedule and will be ready for installation by December 2007.installation by December 2007.

Conclusion Conclusion • Forward

ATLAS• LUCID the












EXTRA SLIDESEXTRA SLIDES



• Use a relatively well Use a relatively well known, copious, known, copious, process:process:

•Inclusive inelastic pp cross-Inclusive inelastic pp cross-sectionsection

• large acceptance at small angleslarge acceptance at small angles

• µ = µ = avg. # of interactions/b.cavg. # of interactions/b.c..

• f = f = frequency of bunch crossingsfrequency of bunch crossings

• inin = = tot inelastic cross-sectiontot inelastic cross-section

• L = L = inst. luminosityinst. luminosity

• Use a good estimatorUse a good estimator•Measure the fraction of crossings with pp interactions

•Use: prob. of no int.

•Direct counting # of pp interactions

•Counting particles•Counting hits

• Cross-calibrateCross-calibrate•Machine information•Roman Pots •Rarer, clean, better understood physic processes

• Use dedicated detector:Use dedicated detector:

fBC in L

˜ fBC in detector L

Strategies for lumi measurementStrategies for lumi measurement

( )P e


October 20 , 2007October 20 , 2007 [ATLAS-LUM-PUB-2006-001]

Measured by LUCID

Measured by LUCID (at low luminosity <1)

Given by calibration method

LUCID with 200 tubes(No Secondaries)

Calibration Constant: A = pp x inel

Run LUCID in parallel with calibration measurement

M

Advantage of “Parallel” Calibration

Measured:Not easy at high precision, e.g. CDF vs E811 discrepancy

Calculated:Acceptance shown at the Tevatron to be difficult to calculate in forward region

Calculated and measured tot used for consistency cross checks

LUCID calibration strategyLUCID calibration strategy



StartStart

up up

QEDQED: small : small QEDQED

– pp pp (p+ (p+*)+(p+*)+(p+*)*)p+(p+()+p)+p Low rate (<< 1 Hz) still at L=10Low rate (<< 1 Hz) still at L=103434 cm cm-2-2 s s-1-1

Process calculated with Process calculated with 1% accuracy 1% accuracy

EWEW: W/Z : W/Z leptons leptons – Theoretically well understood processes (calculated till NNLO)Theoretically well understood processes (calculated till NNLO)

– High rate: High rate: 6Hz for Z6Hz for Z, , 60Hz for W60Hz for Wνν at L=10 at L=103434 cm cm-2-2 s s-1-1

Online monitor at high luminosity Online monitor at high luminosity LL//LL))systsyst ~ 4-6% ~ 4-6% **; ; LL //L L ))statstat ~ 1-5% ~ 1-5% **

QCDQCD: : tottot ~ 100 mb ~ 100 mb

– Roman Pots at dedicated luminosity (L≈10Roman Pots at dedicated luminosity (L≈102727 cm cm-2-2 s s-1-1) and optic) and optic Absolute Luminosity Absolute Luminosity LL

– Counting of the number of bunch crossings with/without Counting of the number of bunch crossings with/without interactioninteraction

Online monitor Online monitor Relative Luminosity Relative Luminosity L L

No Monitor Online

* Small statistical error (<1%) homogeneous samples with at least 10K-100K ev

Physics processesPhysics processes



Cherenkov photons from gas + PMT window

Cherenkov photons from PMT quartz window

1 interaction per event

• Sensitive to IP-pointing tracks above threshold

• Much shorter paths for non pointing secondaries

• The response of the detector is linear with both PMT and fiber read-out

LUCID performancesLUCID performances



During beam pipe bake out LUCID could reach ~250 During beam pipe bake out LUCID could reach ~250 ooC C A cooling system must be employed to keep the A cooling system must be employed to keep the

temperature of LUCID well below 50temperature of LUCID well below 50ooC (PMT specs.)C (PMT specs.) This is achieved using a water cooled aluminium cylinder This is achieved using a water cooled aluminium cylinder

using 6 copper cooling loops (20 litres/hr in each loop)using 6 copper cooling loops (20 litres/hr in each loop) FEA shows that the temperature of the inner radius will be FEA shows that the temperature of the inner radius will be

maintained at a temperature of ~20maintained at a temperature of ~20ooC using this jacket C using this jacket (assuming perfect connection between cooling pipe and (assuming perfect connection between cooling pipe and AlAl))

The cooling system in currently under fabrication in Alberta The cooling system in currently under fabrication in Alberta

The LUCID Cooling SystemThe LUCID Cooling System

The cooling cylinder deployed The cooling cylinder deployed Between the beam pipe and LUCIDBetween the beam pipe and LUCID

Cooling system Cooling system under fabricationunder fabricationat Albertaat Alberta

(Heat dissipated during beam Pipe bakeout is 250 W/m)



No continuous flow of CNo continuous flow of C44FF1010

Pressure maintained (at 1.25/1.5 Bar by regulator) Pressure maintained (at 1.25/1.5 Bar by regulator) leak rate observed less than 10 millibar/dayleak rate observed less than 10 millibar/day

Front PanelSchematic of Gas System

The LUCID Gas SystemThe LUCID Gas System



Test beam venue - SPS H8 in PrevessinTest beam venue - SPS H8 in Prevessin Test Beam period 18Test Beam period 18thth 28 28thth of October 2007 of October 2007 Final assembly of additional components of LUCID Final assembly of additional components of LUCID

for beam test in b154 ( mechanical cage) from the for beam test in b154 ( mechanical cage) from the 1010thth to the 15 to the 15thth of October of October

Next – Test-Beam in Oct. 2007 (1)Next – Test-Beam in Oct. 2007 (1)



Next – Test-Beam in Oct. 2007 (2)Next – Test-Beam in Oct. 2007 (2)

Main goal: calibrate 40 tubes (PMT+MAMPT-with Main goal: calibrate 40 tubes (PMT+MAMPT-with DESY 12/2006 system-) i.e. # p.e./trackDESY 12/2006 system-) i.e. # p.e./track

Determine optimum gas pressure for LUCID runningDetermine optimum gas pressure for LUCID running

The moveable tableThe area in which theThe area in which the table will be placedtable will be placed

The beam dump region



Integration in the ATLAS MC Integration in the ATLAS MC THE

GEO

MODEL

Our stand-alone Monte Carlo predicts satisfactory LUCID performance.

We have started the process of integration of the LUCID into the ATLAS MC

Our aim is to be ready for the Full Dress Rehearsal by the end of 2007



The LUCID Data Flow The LUCID Data Flow



Radiation Hardness A Hamamatsu R762 photomultiplier has been irradiated with a 60Co

source and the dark current and gain has been studied.

PMT 2: No irradiation

PMT 1: 20 MRad in 18 hours

Equivalent to 15 years at 2x1033 cm-2s-1

Equivalent to 3 years at 1x1034 cm-2s-1 The increase of the dark current is not a concern for the PMT lifetime !

V. Hedberg ATLAS Overview Week - 20.02.2007 18



Radiation Hardness

Before irradiation ! No irradiation !

After 20 MRad No irradiation !

V. Hedberg ATLAS Overview Week - 20.02.2007 19



The readout schemeThe readout scheme

PMT 1

PMT 16

MAMPTFED

MAROC

4 diff. TX lines

TRIGGER

CARD

100 m

100 m

100 m

FED USA 15

HV, LV, SLOW CONTROL

ROS

TTCRQ

To LVL1

VME IFOnLineLUMI

3

RX

BOARDS

3

CFD

BOARDS

20

20

VMEQDC/TDC

•INTEGRATED ON TDAQ •ONLINE SCALERS •DEBUGGING VIA VME•MAROC DIGITAL PART NOT AVAILABLE



Scalers in the Trigger Card (Firmware) Scalers in the Trigger Card (Firmware)

for Online Luminosityfor Online Luminosity

LUCID A LUCID C

II. Particle Counting

I. Collision/Zero Counting

16 tubes

1

2

3

4

4 x 3564 x 32bit ~ 60kB (1-4 x BCIDs x Scaler depth) L

R

1

2 (If LUCID A-C Coincidence)

34 (If LUCID A-C Coincidence)

4 x 3564 x 32bit ~ 60kB

III. Total Orbit Counter • For normalization (Average)

• All scalers start/stop are synchronized with the Orbit signal to scale over the same interval at a BC precision• Scalers are incremented on L1A (for dead time correction) • Scalers read-out by VME and sent to DCS (~ 120 kB for each Luminosity Block –few min-) for processing, to be published at any time

32bit



The important steps in The important steps in the LUCID assembly the LUCID assembly sequence followed in sequence followed in July 2007July 2007

The Assembly of LUCID The Assembly of LUCID • LUCID the

basic concept• LUCID the

basic concept• Location • Test beam

studies• LUCID design• LUCID under

construction• Assembly• LUCID


system• The cooling

system• The gas

system• Next test

beam• Next test

beam• MC

integration• Installation• Conclusion

Documents

Antonio Zoccoli RICH 2007 – Trieste 1 October 20, 2007 LUCID* - A Cherenkov tubes based detector for monitoring the ATLAS luminosity LUCID* - A Cherenkov