V. Korbel, DESY 1

9 3/5/02

V.Korbel, DESY

Progress Report on the TESLA Tile HCAL Option

To be filled soon

V. Korbel, DESY 2

The HCAL Calorimeter for the TESLA Detector at DESY

A Tool for Energy Flow Measurement:

The calorimeter is used:•to separate clusters from charged and neutral particles•to measure energy and position (> angle) of neutrals•to track minimum ionising particles

This requires:•rather good energy resolution, •very fine granularity of cells

compared to existing hadronic calorimeters.

At TESLA 2 HCAL options under study:•sandwich scintillator/absorber calorimeter with tile structure•digital sandwich calorimeter with very fine granularity.

V. Korbel, DESY 3

TESLA Detector, cross section

Energy Flow Measurement:

additional information from:•vertex detector•intermediate trackers•TPC

>>•vertex of event•momentum of charged tracks•particle identification•particle impact point at ECAL

V. Korbel, DESY 4

TESLA Detector, cross section, more details

Barrel HCAL EndcapHCAL Endcap

YokeHCAL

Small anglecalorimeters

Full hermeticity down to < xx mrad

V. Korbel, DESY 5

Cut across the barrel calorimeter

16 tapered modules8 x symmetry

Sandwich layers, 38 (53) max:

•5 mm scintillator•1.5 mm gap for fibre RO, reflector foil• 20mm Fe absorber• 1 s/w layer =1.15 X0, 0.12

V. Korbel, DESY 6

The layer structure of the HCAL

Sandwich layers; 38 in barrel,45 in end capswith scintillator tiles:

sizes: ~5x5......~16x16 cm2

~ 800 000 tilesCells:

• cells are non projective• 9 (10) cell layers in barrel (end cap),• grouped from 3,3,3,4,4,4,5,5,7

(3,3,3,4,4,4,5,5,7,7) s/w layerscell volumes:

• (0.22)2 x0.36(0.71)2 x0.84• (1.6 RMoliere)2 x 3.5 X0 ...(5 RMoliere)2 x 8 X0• ~160 000 cells

Optimal HCAL granularity for E-Flow reconstruction of jet energies, ~anglesand jet-jet masses.

V. Korbel, DESY 7

The calorimeter modules:

• 10 cell layers• additional front side ring surrounding end cap ECAL

One of 32 Barrel HCAL modules

Some free space left

1 quadrant

assembled to wheel

End cap HCAL

9 cell layers

V. Korbel, DESY 8

The complete calorimeter

Containment:barrel: 1.1+4.5 =5.6 endcaps 1.1+5.2+5.6 =11.9

Beam hole is closed by the mask calorimeter (Lumi-measurement)

•tungsten (electromagnetic shield)•graphite (neutron shield)

V. Korbel, DESY 9

original fibre RO conceptas described in the TESLA-TDR.

Original concept of tile plate read out

1. layer

Problematic are the small scintillator tile sizes (~ 5x5 cm2)to be read out Study other possibilities

V. Korbel, DESY 10

R&D studies on the tile-WLS fibre system

Green WLS fibre:attenuation length

Scintillatorlight yield

Tileuniformity

Reflector foil:mirror or diffraction,light yield Reflector foil:

LY uniformity

WLS fibre:bending in small radius

WLS fibre:ageing, rad. hardness

WLS fibre:fibre endpolishing and mirroring

Tile-WLS system:• coupling,• light yield,• uniformity>>>> 5x5 cm2, than: 7x7......16x16cm2 tiles

Scintillator :~6600 m2, costs!

R&D

Y-11, KurarayBC-91, Bicron

BC-408,BC-416,SC-306, Protvino

Tyvek,3M Super-reflector

Al-vapour, various reflector paintings,polished optimally

V. Korbel, DESY 11

Details of TFS optimisation studies

Centre/straight fibre Diagonal/bent fibre

Double looped fibre

No stress on fibre,L= cmfibre refl. =tile reflector

more stress on fibre,L= cmfibre refl. =tile reflector

most stress on fibre,probably ageingL= cmfibre refl.inside tile > special reflective coating needed

WLS-clear fibre connectioneasy to implement here

clear RO fibre to couple:max. attenuation length

V. Korbel, DESY 12

R&D studies

• Yield of channel in • recalibration >>• design of detector• construction features• some R&D results• the minical• the HCAL prototype• performance,

preliminary

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WLS fibre end polishing

Enlarged view,20 m

Polished with 3m and 0.3m sand-micro-polishing paper

V. Korbel, DESY 14

Yield of different TF configurations:

scint reflector fibre config. e- in PM fluct/error photons e- in APD e- in Si-PMKuraray SCS 81 Tyvec Y-11 straight-cornwerBicron 408 3M-superrefl. straight middleBicron 416 diagonal bentsc 306 (russ) 2 loops

Bicron 408Bicron 416sc 306 (russ)

Some results:

V. Korbel, DESY 15

Light yield and uniformity for tiles

4.0 – 5.55.0 – 6.54.0 – 6.0Uniformity (%)

15 x 15 10 x 10 5 x 5Tile (cm2)

16 +- 2.815 +- 1.416 +- 1.7LY / photo e- (nA)

2.5 +- 0.24 +- 0.26.5+-0.4 Photo e-

11.5 +- 0.32.4 +- 0.4Relative LY

39 +- 660 +- 4105 +- 6LY (nA)

15 x 1510 x 10 5 x 5Tile a x a (cm2)

•improve LY for large tiles with WLS loops•signal of large cells will be increased by more sampling layers•actual established LY is ~20 pe/cell/MIP•uniformity is ok, needs confirmation by simulation studies.

light yielduniformity

0

5,6

04

0481216202428323640

resp

onse

to S

r90

x axis (cm)

y axis (cm)

V. Korbel, DESY 16

Achievements of the TFS studies:

1. Scintillator: Bicron BC-408, Russian scint. SC301, 65% yield2. 3M Super-reflector3. Kuraray Y-114. Open WLS-end only polished (~0.3 m)4. WLS-fibres glued to tile5. Diagonal bent fibre insertion6. Light yield adjustment with reflector dimmer strip (+/- 4-5%)

More:--ageing studies--uniformity trimming

V. Korbel, DESY 17

[

1

[

[

[

[

Assembled from up to27 scintillator layers:

165 tiles of: 5x5 cm2 >> 45 cells10x10 cm2 >> 8 cells20x20 cm2 >> 2 cells

read out by WLS fibres (without clear RO fibres)

to photodetectors --3x16 MA-PM’s,(H8711), --1x32 APD array,(H-s8550) --Si-PM’s.

Tile and sandwich structure

Track cambers?

A pre-prototype : the „minical“-arrayFor cosmics and e-beam tests

Cell structure

V. Korbel, DESY 18

The need of a HCAL prototype

Study with pions, electrons and muons:---stand alone runs:cluster development and separationangular resolutionlongitudinal and lateral containmentthreshold stability and cross-talksoftware compensationcalibration with muonsstability of LED monitoringnoise contributionenergy resolutionmeasure the constant term

---together with an ECAL prototype:Energy Flow properties,Electron-Pion separation

---compare with digital HCAL version (same HCAL iron stack structure)

To tune the simulation

programsand optimise the

reconstruction !

V. Korbel, DESY 19

HCAL prototypeRequired volume ~ 1 m3~ 800-1200 calorimeter cellsFe-structure is same foranalogue and digital HCAL

10 GeV pions

100 GeV pions

100 cm

Leakagedetector needed!

V. Korbel, DESY 20

Best coupling shape for WLS fibres?Loops ph.e./tile ph./cell•1 7.7 184•2 10.5 256•3 10.0 240unbent fibres:along edge, no groove: 7.0 168along groove in centre 7.7 184diagonal fibre, groove: 10.5 256diagonal, minimal bend: 11.0 264Other criteria to use unbent fibres:

•easy to insert,•less risk of damage •no bending stress,•> less ageing

V. Korbel, DESY 21

The HCAL Calorimeter for the TESLA Detector at DESY

• A Tool for Energy flow measurement:

• The calorimeter is used:• to separate clusters from charged and neutral particles• to measure energy and position (>angle) of neutrals• to track minimum ionising particles• This requires• rather good energy resolution, • very fine granularity of cells compared to existing

HCALs.• At TESLA 2 HCAL options under study:• sandwich scintillator/absorber calorimeter with tile

structure• digital sandwich calorimeter with very fine granularity.

V. Korbel, DESY 22

Summary

List of talks:

How to continue:

V. Korbel, DESY 23

Last transparency

List of talks:

How to continue: