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)
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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
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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
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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)
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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
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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: