14-05-2007 S.Bianco CMS Frascati - LNF Scientific Committee 1 Stefano Bianco Laboratori Nazionali di...

14-05-2007 S.Bianco CMS Frascati - LNF Scientific Committee 1

Stefano Bianco Laboratori Nazionali di Frascati dell’INFN

CMS FrascatiCMS Frascati


OVERVIEWOVERVIEW

1.Where do we come from2.CMS and the RPC muon detectors3.Gas contaminants studies4.Gas gain monitoring system5.Physics analysis tasks6.Papers7.Conclusions


Historical Touch (I)Historical Touch (I)

Our group forms in the 80’s with NA1 at CERN, then activity in FOCUS at Fermilab, LVD at G.Sasso, KLOE and FINUDA at LNF and finally BTeV at Fermilab.

Previous experience in HEP detectors concentrated on calorimetry (NA1, FOCUS, KLOE) and strawtubes (FINUDA and BTeV).

Traditional physics topics of interest in Heavy Flavours spectroscopy (FOCUS). Strong activity in FINUDA analysis (hypernuclear spectroscopy).


Historical Touch (II)Historical Touch (II)

In BTeV our group conceived, proposed and developed the strawtube-microstrips integration in the forward tracker, introducing the novel solution of glued straws embedded in a Rohacell lattice without mechanical tension.

We also introduced the Fiber Bragg Grating sensors technique in HEP, using them in FINUDA for the first time, and generalizing their use in BTeV for straws, microstrips and pixels.

Fixed frame

Sliding frame

λ

Response signal

Δλ(Δσ)

λ(σ0)

FBG Optical fibre

Response signal

Probe signal


A small group with a tradition A small group with a tradition for for

HEP detectors design, HEP detectors design, construction and operation, construction and operation, and a strong motivation to and a strong motivation to

physics analysisphysics analysis


Historical Touch (III)Historical Touch (III)

•BTeV was canceled by US DOE in February 2005

•In April 2006 CMS Frascati was approved and funded by INFN


CMS at the CERN LHCCMS at the CERN LHC http://cmsinfo.cern.ch/Welcome.html/http://cmsinfo.cern.ch/Welcome.html/


Resistive Plate CounterResistive Plate Counter muon detector muon detector

Gas mix used is 96.2% C2H2F4 / 3.5% Iso-C4H10 / 0.3% SF6


RPC muon detectorRPC muon detector


L.Benussia, M.Bertania, S.Biancoa, A.Brotzuc, M.A.Caponerob, D.Colonnac , D.Donisib, F.L.Fabbria, F.Fellic, M.Giardonia, B.Ortenzia,

M.Pallottaa, A.Paolozzid, L.Passamontia, D.Pierluigia, A.Russoa, B.Ponzioa, C.Puccid, G.Savianoc

aLaboratori Nazionali di Frascati dell’INFN, ItalybLaboratori Nazionali di Frascati dell’INFN and ENEA Frascati, Italy

cLaboratori Nazionali di Frascati dell’INFN and Facolta’ di Ingegneria Roma1, Italy dLaboratori Nazionali di Frascati dell’INFN and Scuola di Ingegneria aerospaziale Roma 1, Italy

In 2007: 7.5 FTE staff+PhD, 1.5 FTE technicians

CMS FrascatiCMS Frascati


Tasks and Responsibilities in Tasks and Responsibilities in CMSCMS

CMS Frascati was approved andfunded by INFN in April 2006.Frascati Tasks:

•Cabling coordination (D.Colonna)

•QC at production site •Gas purity and material studies, Gas gain monitoring system (S.Bianco)

•Analysis


LNF located at ~80km from RPC production LNF located at ~80km from RPC production sitesite


Quality Control at General Quality Control at General Tecnica (Colli, FR)Tecnica (Colli, FR)


• Resistive Plate Chambers (RPC) detectors are widely used in HEP experiments for muon detection and triggering at high-energy, high-luminosity hadron colliders, in astroparticle physics experiments for the detection of extended air showers, as well as in medical and imaging applications.• While gain and efficiency stability are always a must, in the case of RPC detectors in high-rate experiments which use freon-based gas mixtures, utmost care has to be paid also for the possible presence of gas contaminants.•The RPC detector of experiment CMS at the LHC proton collider (CERN, Switzerland) will employ a gas analysis and monitoring system for the online monitor of the freon-based gas mixture used.• The gas monitoring system is based on small RPC detectors whose working point (gain and efficiency) is continuously monitored online. The gas monitoring system is designed to provide fast and accurate determination of any shift in working point conditions.• Quantitative gas chemical analysis is then performed online by a complete system which includes gas-chromatography, pH sensors and contaminants (notably HF) detectors.

GAS STUDIESGAS STUDIES


• Because of high cost and huge volumes of Because of high cost and huge volumes of the Freon-based gas mix used, CMS will use the Freon-based gas mix used, CMS will use a recirculation (Closed Loop) gas system a recirculation (Closed Loop) gas system developed by the CERN gas group.developed by the CERN gas group.

• The Closed Loop is a critical component of The Closed Loop is a critical component of RPC. CMS has accumulated experience on RPC. CMS has accumulated experience on its use and performances during the test at its use and performances during the test at the Gamma Irradiation Facility at CERN in the Gamma Irradiation Facility at CERN in 2001, and currently at the ISR where 2001, and currently at the ISR where chambers are tested in CL prior to chambers are tested in CL prior to installation. installation.

• At the GIF facility we observed substancial At the GIF facility we observed substancial production of HF, linearly correlated with production of HF, linearly correlated with the signal current the signal current

THE CMS CLOSED LOOP GAS THE CMS CLOSED LOOP GAS SYSTEMSYSTEM


CLOSED LOOP GAS CLOSED LOOP GAS RECIRCULATIONRECIRCULATION

Purifiers are THE crucial component


SEM-EDS STUDY OF SEM-EDS STUDY OF IRRADIATED RPCsIRRADIATED RPCs

Anode

Cathode

We opened RPCs irradiated at the GIF and observed defects on the inner surfaces.

SEM image of a defect with two magnificationsSEM image of a defect with two magnifications

We performed SEM-EDS and XRD analyses on- and off-defect…


Reference bakeliteReference bakelite

On-defectOn-defect

SEM / EDS analysis of defects SEM / EDS analysis of defects inside irradiated RPCinside irradiated RPC

Peaks of NaF

Peaks of defectsOn-defect

Na peak

Off-defect

F peak

•Presence of Na in defects from bakelite

•Preliminary XRD results show presence of

NaF. http://arxiv.org/pdf/physics/0701014

http://arxiv.org/pdf/physics/0701014..


CERN Closed Loop Gas SystemCERN Closed Loop Gas System

• We proposed to study presence of We proposed to study presence of contaminants and their type ofcontaminants and their type of accumulation in accumulation in the Closed Loop Gas system (same for CMS and the Closed Loop Gas system (same for CMS and ATLAS) ATLAS)

• Current values in ISR Test Chambers decrease Current values in ISR Test Chambers decrease as the gas circulation changes from a closed to as the gas circulation changes from a closed to an open loop an open loop

• We are coordinating a three-phase study of CLWe are coordinating a three-phase study of CL– Phase 1 September 06 - study contemporaneous to Phase 1 September 06 - study contemporaneous to

chamber testing. Limited by current values. chamber testing. Limited by current values. – Phase 2 March 07 - Dedicated testing of DG’s and Phase 2 March 07 - Dedicated testing of DG’s and

SG’sSG’s– Phase 3 ? - Dedicated testing at GIF possibly Phase 3 ? - Dedicated testing at GIF possibly

synergy with ATLASsynergy with ATLAS


CERN Closed Loop Gas CERN Closed Loop Gas systemsystem

• All system components should be All system components should be characterized:characterized:– Bakelite (all different types of bakelite)Bakelite (all different types of bakelite)– Zeolite (all different zeolite filters)Zeolite (all different zeolite filters)– Other filters based on Cu and Zn and oxidesOther filters based on Cu and Zn and oxides– Gas Gas

by means of a systematic sampling of the by means of a systematic sampling of the different parts during all of the system different parts during all of the system work phaseswork phases


Phase 1: ISR sampling Phase 1: ISR sampling September 2006September 2006

• Samples (unused, contaminated, Samples (unused, contaminated, regenerated) have been collected:regenerated) have been collected:– Purifiers:Purifiers:

• Zeolite Zeolite

• Ni AlNi Al22OO3;3;

• Cu, Cu ZnCu, Cu Zn

– Pipes CuPipes Cu– Neither oiled nor used bakeliteNeither oiled nor used bakelite– Unused bakelite oiled with graphite Unused bakelite oiled with graphite


Table of analyses Table of analyses


Zeolites characterization now used Zeolites characterization now used in CLin CL

Different zeolite filters have Different zeolite filters have been used : 3A, 5A. been used : 3A, 5A.

They differ in their grain size They differ in their grain size dimensions, framework pores dimensions, framework pores amplitude and chemical amplitude and chemical compositioncomposition

• 4A (4 4A (4 Å, Na)Å, Na)• 3A (3 Å, K)3A (3 Å, K)• 5A (5 Å, Ca)5A (5 Å, Ca)• Grain size distribution has Grain size distribution has

been been performedperformed on zeolite on zeolite filters :filters :

• 33ÅÅ (25 gr) (25 gr) 1,4 mm1,4 mm (8 gr) (8 gr) 1 mm1 mm (17 gr) (17 gr)• 55ÅÅ (25 gr) (25 gr) 2,8 mm2,8 mm (16 gr) (16 gr) 2 mm2 mm (9 gr) (9 gr)


Type A zeolitesType A zeolites• Framework of Framework of

Linde Type A Linde Type A zeolites zeolites

• 4A (4 4A (4 Å, Na)Å, Na)• 3A (3 Å, K)3A (3 Å, K)• 5A (5 Å, Ca)5A (5 Å, Ca)


Linde Type A zeolite Linde Type A zeolite (Na(Na9696(H(H22O)O)216216[Si[Si9696AlAl9696OO384384] ]

XRD performed at University of Rome “La Sapienza” on a sample of unused zeolite. On the right, the reference pattern for standard Linde Type A zeolite.

REFERENCE


Characterization of zeolite and Characterization of zeolite and other filters (Cu, Cu Zn; Ni, other filters (Cu, Cu Zn; Ni,

AlAl22OO33))• Zeolites and otherZeolites and other filters have been sampled (unused, filters have been sampled (unused, contaminated, regenerated). On these samples, analyses have contaminated, regenerated). On these samples, analyses have been performed:been performed:– Chemical analyses on major and trace elements, also sulphur, and Chemical analyses on major and trace elements, also sulphur, and

carbon (graphitic, total and organic) carbon (graphitic, total and organic) – Ionic chromatography to analyze fluorine Ionic chromatography to analyze fluorine – XRD analyses to identify zeolite and to evaluate a possible XRD analyses to identify zeolite and to evaluate a possible

crystalline structure of compounds, occurring after gas filteringcrystalline structure of compounds, occurring after gas filtering

The aims of these analyses are:The aims of these analyses are:• to characterize contaminants in filtersto characterize contaminants in filters• to identify their form (crystalline, in solution, amorphous)to identify their form (crystalline, in solution, amorphous)• to define the filters composition after regenerationto define the filters composition after regeneration


Instrumentation available at University of Rome Instrumentation available at University of Rome “La Sapienza” (Faculty of Engineering)“La Sapienza” (Faculty of Engineering)

• Stereomicroscope Leica Wild M10Stereomicroscope Leica Wild M10• SEM Hitachi S2500, equipped with a SEM Hitachi S2500, equipped with a

Kevex X-ray Microanalizer.Kevex X-ray Microanalizer.• XRD Philips X’Pert Plus diffraction systemXRD Philips X’Pert Plus diffraction system• HPLC ionic chromatography (High HPLC ionic chromatography (High

Performance Liquid Chromatography), Performance Liquid Chromatography), made up of a Shimadzu LC-10ATvp pump made up of a Shimadzu LC-10ATvp pump and a column Shodex ICSI-50 4E, and a and a column Shodex ICSI-50 4E, and a conductivity detector CDD-10Asp.conductivity detector CDD-10Asp.

• Roughness tester Mitutoyo SurftestRoughness tester Mitutoyo Surftest• Sample preparation setsSample preparation sets


Traces of S and F in filters Traces of S and F in filters


Closed loop Studies Closed loop Studies SummarySummary

• Closed loop filters detemined in 2001 at gif by Closed loop filters detemined in 2001 at gif by looking at GC peakslooking at GC peaks– CAVE: Not everything bad for RPC shows up in a GCCAVE: Not everything bad for RPC shows up in a GC

• Rigorous sampling in September 2006Rigorous sampling in September 2006– New materialsNew materials– Used materialsUsed materials– Regenerated materialsRegenerated materials

• A broad-spectrum analysis campaign A broad-spectrum analysis campaign (reference) to single out problems and to (reference) to single out problems and to design more focussed analyses.design more focussed analyses.

• CMS Frascati provided specific expertise and CMS Frascati provided specific expertise and instrumentation for the solution of a basic instrumentation for the solution of a basic open problem - gas purifiersopen problem - gas purifiers


A monitoring system of the RPC working point:A monitoring system of the RPC working point:– able to provide much faster and sensitive response than the CMS able to provide much faster and sensitive response than the CMS

RPC system RPC system Monitor efficiency and charge continuously - 1 hour cyclesMonitor efficiency and charge continuously - 1 hour cycles

1% precision1% precision Monitoring of charge and efficiences with cosmic rays (20 Hz/pads) Monitoring of charge and efficiences with cosmic rays (20 Hz/pads)

in SGX5 gas buildingin SGX5 gas building Three sub-systems of 45x45 cmThree sub-systems of 45x45 cm22 pads in the same telescope pads in the same telescope

1 Reference with clean open loop gas mix1 Reference with clean open loop gas mix

2 Monitor “OUT” with close loop downstream of CMS RPCs2 Monitor “OUT” with close loop downstream of CMS RPCs

3 Monitor “IN” with close loop upstream of CMS RPCs3 Monitor “IN” with close loop upstream of CMS RPCs Multiplexed monitor on half-wheel gas line as future upgradeMultiplexed monitor on half-wheel gas line as future upgrade

In case work point changesIn case work point changes– alarm goes on alarm goes on action needed action needed– Gas quality monitoring systems (GC,probes, etc) verify what the Gas quality monitoring systems (GC,probes, etc) verify what the

change of working point is due to.change of working point is due to.

GAS GAIN MONITORING SYSTEMGAS GAIN MONITORING SYSTEM


USC5UXC5

C2H

2F 4

/SF 6

/i-

C4H

10 /

H2O

Slow CtrlGC, p/T/RH/Ph

CMS

VENT

PU

RIF

IER

S

SGX Bldg

RPC TRIG2RPC TRIG1

RPC TRIG4RPC TRIG3

RPC PAD REF2RPC PAD REF1

RPC PAD MON6RPC PAD MON5

REFERENCE half wheel lines

VENT

VENT

RPC PAD MON4

RPC PAD MON3RPC PAD MON2RPC PAD MON1MONITOR

VENT

Gas Gain Monitor (conceptual designGas Gain Monitor (conceptual design))

VENT


– Reading RPCs with two pads placed on both sides of Reading RPCs with two pads placed on both sides of detectors for timing, efficiency and charge detectors for timing, efficiency and charge

Gas Gain Monitor (conceptual designGas Gain Monitor (conceptual design))

knee

+2

00

-20

0

Three monitoring RPC with independent Three monitoring RPC with independent HV supply, on and off knee HV supply, on and off knee

Clean cosmic rays peak provide Clean cosmic rays peak provide accurate monitor of working pointaccurate monitor of working point

Ref.: S.Nuzzo 200610x10cm2 pad


GAIN MONITORING SYSTEMGAIN MONITORING SYSTEM

READOUT PAD

Foam


PROTOTYPE 45x45cmPROTOTYPE 45x45cm22 double-pad double-pad


GAS GAIN MONITORING - DOUBLE GAS GAIN MONITORING - DOUBLE PAD READOUTPAD READOUTPads 45x45cm2 positive and negative

Sum pulseDEVELOPING DIFFERENTIAL AMPLIFICATION SCHEME

TO REDUCE COHERENT NOISE

Cosmic ray event triggered

by scintillation

counters hodoscope



Charge distribution of avalanche from cosmic rays at voltages Charge distribution of avalanche from cosmic rays at voltages from 9.5kV to 10kV. Charge readout from 45x45cmfrom 9.5kV to 10kV. Charge readout from 45x45cm2 2 pads fed to pads fed to TEKTRONIX TDS5000 scope.TEKTRONIX TDS5000 scope.

CMS RPC preliminaryCMS RPC preliminary

Gas mix used is 96.2% C2H2F4 / 3.5% Iso-C4H10 / 0.3% SF6



CMS RPC preliminary

Positive pad

Positive pad

Negative pad

Negative pad

Fitting charge distributions with truncated gaussians shows expected linear dependance of charge on HV (saturated avalanche). Peak is determined with a 1% accuracy for 104 event samples.


AVALANCHE TO STREAMER TRANSITIONAVALANCHE TO STREAMER TRANSITION

Charge distribution on Charge distribution on 45x45cm45x45cm22 pad showing pad showing transition from avalanche to transition from avalanche to streamer. At t=0 standard gas streamer. At t=0 standard gas mix contains 0.3% SFmix contains 0.3% SF66, which is , which is progressively removed. As SFprogressively removed. As SF66 is decreased, the streamer is decreased, the streamer peak appears.peak appears.

0.3%

SF 6

0.0%

SF 6


Our FEE options under test Our FEE options under test 1/61/6

Type A0 - Type A0 - LM6172 LM6172 - Dual High Speed, Low Power, Low Distortion Voltage Feedback - Dual High Speed, Low Power, Low Distortion Voltage Feedback AmplifiersAmplifiers

Gain Bandwidth 100 MHzGain Bandwidth 100 MHz

Slew Rate 3000 Volts/usecSlew Rate 3000 Volts/usec

SupplyCurrent Per Channel 2.3 mASupplyCurrent Per Channel 2.3 mA

Supply Min 5.5 VoltSupply Min 5.5 Volt

Supply Max Supply Max 36 Volt36 Volt

Type A1 - Type A1 - Max 435 DMax 435 Differential, High Speed Op Ampifferential, High Speed Op Amp

Gain BandwidthGain Bandwidth 275 MHz275 MHz


SupplyCurrent Per Channel 18 mASupplyCurrent Per Channel 18 mA

Supply Min 5 VoltSupply Min 5 Volt

Supply Max 12 VoltSupply Max 12 Volt

Type A2 - Type A2 - LMH6550 LMH6550 Differential, High Speed Op AmpDifferential, High Speed Op Amp

Gain Bandwidth 400 MHzGain Bandwidth 400 MHz


SupplyCurrent Per Channel 20 mASupplyCurrent Per Channel 20 mA

Supply Min 5 VoltSupply Min 5 Volt

Supply Max Supply Max 12 Volt12 Volt

Out

Pad +

Pad -

TRASFORMATORI (Zero centrale)TRASFORMATORI (Zero centrale)

Tipo ATipo A

Ferrite Diametro 30mm spessore 6mFerrite Diametro 30mm spessore 6mmm

Tipo BTipo B

Ferrite Diametro 30mmFerrite Diametro 30mm spessore 12mmspessore 12mm

Tipo CTipo C

Miniatura diametro 6mm spessore 3mmMiniatura diametro 6mm spessore 3mm

Several amplification schemes are being explored. Even a simple passiveSeveral amplification schemes are being explored. Even a simple passive

sum of positive and negative pads and feeding to standard LRS612AMsum of positive and negative pads and feeding to standard LRS612AM ampliampli

improves the S/N ratio.improves the S/N ratio.


AMPLI OptionAMPLI Option

<-

PED

ESTA

L

CMS RPC preliminary

HV=9700V

Pad +

Pad -

Filtro PassaBanda 100KHz – 80MHz

OscilloscopioLecroy / Tektronix

10pF100uH

10nF 4uH


RACKS LAYOUT IN SGX5RACKS LAYOUT IN SGX5

1112

1 and 1/2 racksFor gas gain monitor

Only gas, no electronics

Lateral accessMinimize signal cables lengths

Gas

qua

lity

her

e +

pip

ing,

valv

es,G

C ?


SISTEMA PRONTO A GTSISTEMA PRONTO A GT2/5/072/5/07


Integration of Gas Gain Monitoring gaps Integration of Gas Gain Monitoring gaps with the CERN gas systemwith the CERN gas system


Physics StudiesPhysics Studies

• Channels with muon pairs (from J/psi, Channels with muon pairs (from J/psi, Upsilon(4s)), profiting of knowledge of RPC Upsilon(4s)), profiting of knowledge of RPC and DT muon detectorsand DT muon detectors

• Spectroscopy of Bc-->J/psi Spectroscopy of Bc-->J/psi • Mixing of Bs --> J/psi Mixing of Bs --> J/psi • CPV in Bs --> J/psi CPV in Bs --> J/psi


Papers 2006-2007Papers 2006-2007• Preprints and ConferencesPreprints and Conferences

– S.Bianco on behalf of the CMS RPC Collaboration, “The gas gain monitoring S.Bianco on behalf of the CMS RPC Collaboration, “The gas gain monitoring system for the CMS RPC detector”, IEEE06, San Diego (USA) system for the CMS RPC detector”, IEEE06, San Diego (USA) http://arxiv.org/pdf/physics/0701014http://arxiv.org/pdf/physics/0701014..

– C.Pucci “CMS RPC gas gain system”, Annual Congress of Italian Physical C.Pucci “CMS RPC gas gain system”, Annual Congress of Italian Physical Society, Torino 2006Society, Torino 2006

– D.Colonna “Use of FBG sensors for high precision silicon detectors”, D.Colonna “Use of FBG sensors for high precision silicon detectors”, Annual Congress of Italian Physical Society, Torino 2006Annual Congress of Italian Physical Society, Torino 2006

– M.Abbrescia et al., Proposal for a detailed study of Closed Loop… Frascati M.Abbrescia et al., Proposal for a detailed study of Closed Loop… Frascati Preprint LNF 06/27 (IR) available at Preprint LNF 06/27 (IR) available at http://www.http://www.lnflnf..infninfn.it/sis/preprint/.it/sis/preprint/

– M.Caponero et al., “On the use of FBG sensors in CMS” Siena conference M.Caponero et al., “On the use of FBG sensors in CMS” Siena conference on adv. Detectors Nov 2006 (to appear on NIM)on adv. Detectors Nov 2006 (to appear on NIM)

– A.Paolozzi et al., “Performances of FBG sensors for application at LHC A.Paolozzi et al., “Performances of FBG sensors for application at LHC experiments”, Vienna conference Feb 2007 (to appear on NIM)experiments”, Vienna conference Feb 2007 (to appear on NIM)

– S.Bianco et al., Omega-Like Fiber Bragg Grating Sensors as Position Monitoring S.Bianco et al., Omega-Like Fiber Bragg Grating Sensors as Position Monitoring Device: A Possible Pixel Position Detector in CMS? Frascati preprint LNF- 06/13(NT)Device: A Possible Pixel Position Detector in CMS? Frascati preprint LNF- 06/13(NT)

• Masters and PhD ThesesMasters and PhD Theses• C.Pucci Analisi dei materiali nelle RPC di CMS Frascati preprint C.Pucci Analisi dei materiali nelle RPC di CMS Frascati preprint LNF - 06 / LNF - 06 /

31(Thesis)31(Thesis)• D.Colonna Applicazione dei sensori FBG in HEP e nelle strutture Marzo 2007D.Colonna Applicazione dei sensori FBG in HEP e nelle strutture Marzo 2007

http://www.lnf.infn.it/sis/preprint/






CONCLUSIONSCONCLUSIONS

•CMS Frascati was approved and funded by INFN in April 2006, just a little over one year after the BTeV cancellation•We have brought into the CMS RPC Collaboration important contributions in HEP detectors and materials science, and we now have a leading role in the gas studies

•Cabling coordination (D.Colonna)

•QC at production site •Gas purity and material studies, Gas gain monitoring system (S.Bianco)

•CMS RPC is a unique playground for well-motivated students for both Physics and Engineering.•CMS Frascati benefits from excellent, well-motivated Engineering students.•The inflow of Physics students is more difficult, active search now in place to attack the topics of interest in physics analyses


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