CMS Outer Hadron Calorimeter (HO) Project Naba K Mondal Tata Institute, Mumbai, India HO-EDR Presentation, 10th June, 1999

CMS Outer Hadron CMS Outer Hadron Calorimeter (HO) ProjectCalorimeter (HO) Project

Naba K Mondal

Tata Institute, Mumbai, India

HO-EDR Presentation, 10th June, 1999

CMS HCAL-HO EDR, June 99

HO EDR AgendaHO EDR Agenda

June 10, 1999

HO design and test beam results Naba Mondal HO Hanging structure design D. Dattola HO production with emphasis on QC/QA Sudeshna Banerjee Tile grooving and test facilities at Panjab University J. Singh HO organisation and Planning Naba Mondal


Responsibility ChartResponsibility Chart

HO MechanicsCERN

Optics ManufacturingTata Institute, MumbaiPanjab University, ChandigarhCentral Workshop, BARC, Mumbai

Decoder box, ElectronicsUS-CMS groups


Need for HONeed for HO

In the central region, HB is not thick enough to contain hadronic shower fully, particularly those fluctuated showers which develop deep inside the HCAL.

Need to extend HCAL outside the solenoid magnet and make additional sampling of the shower.

This part outside the magnet coil is referred as Outer Hadron Calorimeter (HO)


HO LocationHO Location

Geographically located just below the muon system and hence is constrained by the geometry of the muon system.


HO CoverageHO Coverage

HO covers the central rapidity region ( < 1.26) occupied by the five Muon Rings. ( numbered as -2,-1,0,1,2)

For Ring 0, there will be two HO layers ( Layer 0 & 1) on either side of the 18 cm thick tail catcher iron at R=3.82 m and 4.07 m

For Rings -2,-1,1 & 2, there will be a single HO layer ( Layer 1) at R= 4.07 m


Simulation StudySimulation Study

Use CMSIM Version 113 for CMS detector simulation Use tracker geometry as in post-ECAL pre-Tracker TDR Use ECAL geometry as in ECAL TDR Barrel inner hadron calorimeter with 17 layers in front of the coil HO consists of:

Two layers in ring 0 on either side of the tail catcher iron One layer in rings 2,1,-1 & -2

Showers are generated using GEANT for electromagnetic and GHEISHA for hadronic component



Effect of leakage is visible from 70 GeV and increases with energy

Effect of leakage is smaller at higher



Energy resolution:

The constant term improves after addition of HO

Fraction of events having measured energies 3 below the mean value

Leakage is < 1%


1996 Test beam results1996 Test beam results

Energy Resolution

Leakage



Effect of HBO on missing energy

QCD events


Design ConsiderationDesign Consideration

• Basic Detector Elements should map the barrel hadron Calorimeter ( HB) towers of granularity 0.087 X 0.087 in and

• Should be able to see MIPS.

10 mm thick Bicron BC408 scintillatorto be used as the active element.

Use 0.94 mm dia WLS Kuraray double clad fibers ( in shapped grooves), splicedto clear fibers to carry light to HPDs locatedon the outer edge of the muon system.


HO segmentationHO segmentation

HO Segmentation along HO in each ring is divided into 12 identical sectors, each covering

300 in Each sector has six slices- each covering 50 ( = 0.087)

Width of slices in mm

Ring 0: Layer 0:

285.9 349.2 338.5 333.4 333.4 279.6

Ring 0: Layer 1:

311.3 369.9 358.6 353.2 353.2 303.8

Ring -2,-1,1 and 2: Layer 1:

328.8 372.1 360.8 355.3 355.3 417.7


HO segmentationHO segmentation

segmentation along Total coverage along in each ring : 2.51 mLength along in mm ( Edge towers are truncated due to geometrical constraints}

Ring 0 - eight towers Ring 1/-1 - six towers Ring 2/-2 - five towers

Tower # Lay-0 Lay-1 Tower # Lay 1 Tower # Lay 1

4 249.1 189.3 5 & -5 391.8 11 & -11 420.4

3 339.5 359.7 6 & -6 394.7 12 & -12 545.6

2 334.5 354.3 7 & -7 411.4 13 & -13 583.8

1 331.9 351.7 8 & -8 431.4 14 & -14 626.6

-1 331.9 351.7 9 & -9 454.5 15 & -15 333.7

-2 334.5 354.3 10 & -10 426.2

-3 339.5 359.7

-4 249.1 189.3


HO Tile designHO Tile design

Light from individual tile is collected using WLS fiber.

Fibers are held inside the tile in keyhole type grooves

There will be 4 identical shaped grooves per tile.

HO has 95 different tile dimensions, 75 for layer 1 and 20 for layer 0.

Total number of tiles -- 2736


HO Tray DesignHO Tray Design

All the tiles in the same slice of a ring will be packed as a single mechanical unit called the “tray”.

It will cover the entire length of a muon ring along Z.

Along , it will only be one tile wide ( 50)


HO Tray AssemblyHO Tray Assembly

Tiles in a tray will be covered with tyvek and tedler.

Will be sandwiched between two plastic plates of 2mm and 1mm thickness for mechanical stability and ease of handling.

2mm thick plastic cover will have grooves to route the fibers from tiles to edge connector.

Additional groove for the source tube


Picture of a trayPicture of a tray


Full TrayFull Tray


Light collectionLight collection

Clear fibers spliced to WLS fiber will transport scintillation light to an optical connector located at the edge of the tray.


Optical Cable RoutingOptical Cable Routing

Optical cables made of 0.94 mm diameter clear fibers carry light from the tray connector to the HPDs located in a Decoder box outside the muon system


List of HO itemsList of HO items

No of Tiles : 2736

No of Trays : 432

No of Pigtails : 864

No of Optical cables : 864

Area of Scintillator : 380 m2


Material Safety InformationMaterial Safety Information

Scintillator Name : BC 408

Chemical Name : Polyvinyl Toluene ( >97% wt)

& Organic Fluors ( < 3% wt)

Formula : C10H11

Flash Point : None

Unusual Fire and Explosion Hazards : None

Avoid : Temperatures above 3000 C

Respiratory Protection : When machining or polishing

wear and approved dust respirator


Pre Production Prototype Pre Production Prototype SectorSector

Aim:

To test a small number of modules using test beam to establish the production procedure and to optimise the detector design:

PPP1: Cover 200 in and one half barrel ( 2 and 1/2 rings) in Z

Need: 8 half length Trays ( 1.27 m) for ring 0

8 full length Trays ( 2.54 m) for rings 1 & 2

# of Tiles : 76

# of pigtails : 32

These Trays were exposed to test beams at CERN in the summer of 98

PPP2: Additional 8 trays made and transported to CERN this year to cover one

sector completely for this year’s combined run with HB and HE modules


Test Beam ModulesTest Beam Modules

PPP tile with 4 grooves visible

Pigtial with connector

Finished

Tray


1998 Test Beam Setup 1998 Test Beam Setup


Test Beam ResultsTest Beam Results

Response of the HO tiles was measured With Cosmic ray Muons (with PMTs) at TIFR With muon beams at CERN

Using HPDs with D0 pre-amplifier electronics Using HPDs with QIE prototype electronics ( Proof of principle)

Using radioactive wire source Using X-Y scanner


Cosmic Test SetupCosmic Test Setup


Cosmic Ray test of PPP Cosmic Ray test of PPP traystrays

After fabrication the trays were tested using cosmic ray muons at TIFR, Mumbai .



Pedestal subtracted muon ADC signal from a ring 0 HO tower-

(layer 0 and layer 1 combined)

Signal = 34.7, p= 9.4, S/N = 4

Pedestal subtracted muon ADC signal from a ring 1 tile ( Single layer).

Signal = 18, p=10, S/N = 1.8



Fine scan of an HO tile ( Tile # 124) using 2 cm X 2cm beam spot to test tile uniformity


Test Beam CalibrationTest Beam Calibration

LED data was used for calibration of individual channels.


Photo Electron yield due to Photo Electron yield due to MIPMIP

For HO tiles, we have estimated p.e. yields using test beam muon spectrum and the LED calibration data

Ring 0 Tiles

Ring 1 Tiles

TileID

PedestalRMS

SignalPeak

S/N CalibrationPE/ADC

Yield(No ofP.E./Mip

O23 7.2 28 4 0.6 17

024 6.6 22 3 1.1 24

033 6.7 21 3 1.0 21

032 8.1 23 3 0.7 17

012 9.1 35 4 0.5 20

114 6.5 10.5 1.6 0.9 10

113 5.6 9.7 1.7 1.3 12

123 6.5 12.9 2 0.6 8


Source CalibrationSource Calibration

HO trays have also been calibrated using wire source scanner as well as X-Y source scanner


HO with QIE + HPDHO with QIE + HPD

Muons could be seen in HO with the QIE + HPD contained within 2 time slices of 40 MHz.


SummarySummary

Need for an Outer Hadron Calorimeter (HO) in the barrel region has been established. Simulations and test beam results show that HO will improve the energy resolution and is necessary for physics involving missing Et.

We have a detailed Engineering design for HO. We have tested Pre-Production Prototype (PPP) Modules with HPD

readouts using muon beam at CERN in 1998. Results show that we are sensitive to MIPs which is one of our design goals.

We have also tested these modules using radioactive wire source as well as using X-Y source scan.

Through the exercise of producing the PPP modules, we have developed all the tools and necessary procedures for QC/QA and are ready to enter the production stage.


HO Technical BoardHO Technical Board

Within India-CMS collaboration we have a Technical Board to discuss and decide on various technical issues related to HO.

Current Members of the Technical Board: Naba K Mondal (Coordinator) Atul Gurtu M.R.Krishnaswamy K.Sudhakar J.B.Singh R.S.Koppikar S.N.Ganguli (India-CMS contact person)


HO Task CoordinatorsHO Task Coordinators

Task Production in charge QC inchargeMaterial Acceptance B.S.Acharya

Machining of tiles at Mumbai K.Sudhakar S.R.Dugad

Machining of tiles at Chandigarh Jasbir Singh Suman Beri

Pigtail Manufacturing S.R.Chendvankar & B.Satyanarayana Manas Maity

Final Assembly Sudeshna Banerjee & Manas Maity S.D.Kalmani

Final Testing P.Nagaraj & Mandakini Patil K.Mazumdar

Storage & Shipping L.V.Reddy

HO related Database P.V.Deshpande & P Nagaraj

Naba K Mondal : Technical Coordinator M.R.Krishnaswamy : Incharge of overall Quality Control J.M.Kohli : Incharge of the Chandigarh Center


Production ResponsibilitiesProduction Responsibilities

Machining of Scintillator tiles will be done at two centers 25% of tile grooving and the necessary QC will be done at Chandigarh 75% of tile grooving at Mumbai ( TIFR & BARC)

All the remaining jobs will be done at the Optics Centre, TIFR, Mumbai with participation from Chandigarh group

Procurement of all raw materials ( Scintillator sheets,WLS and Clear fibers, Tyvek and Tedler sheets, plastic sheets, cutters etc) will be done through the Mumbai center.

Shipment of all the trays will be done through the Mumbai centre


Introduction to HO ProjectIntroduction to HO Project

Naba K Mondal

TIFR, Mumbai, India

Documents

CMS Outer Hadron Calorimeter (HO) Project Naba K Mondal Tata Institute, Mumbai, India HO-EDR Presentation, 10th June, 1999