GARGAMELLE

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GARGAMELLE
Leptonic neutral current
The beginning of the experimental studies of the
electroweak theory
Now, we are talking about experimental studies
to understand the processes of the EW symmetry
breaking
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4th ECFA/DESY workshop Summary of the
Calorimeter studies
What was our view at the beginning of the 4th
ECFA workshop What is the paradigm today
What has been achieved in the RD What
remains to do in the short-mid term in the
longer studies What could be the future goal
for the 5th ECFA studies
Jean-Claude BRIENT LLR-IN2P3
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The main principles (can be seen as obvious
today, but )

• Start from the PHYSIC program
• change with time (i.e. recent interest for the
  capability to measure the tau polarization)
• Identify the need and how to fulfil it
• Make a list of requirements, like ?Ejet,
  ?Mdi-jet, photon IP, etc
• Look for pseudo-realistic device
• What is pseudo-realistic/not realistic is
  relatively elastic
• Establish the distance between pseudo-realistic
  to realistic device
• Prototype and test beam are clearly the best way
  to do it

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Our view at the beginning of the 4th ECFA
ECAL

• SHASHLIK
• TILE for US-LCD-LD and ACFA
• W-Si for TDR and US-LCD-SD

Energy resolution single particle (10/?E was a
good argument) Pion/electron
separation Importance of performance in
multi-jet events (not quantified)
HCAL

• TILE for TDR, US-LD, ACFA
• optimal size of tile
• photodetectors
• S/N at mip
• Digital for TDR
• is it real effect ?
• shower size ?
• energy resolution ?

Energy resolution single particle (40/?E was a
good argument) Importance of performance in
multi-jet events (not quantified)
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The Graal is the jet business
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ECAL
Tungsten-silicon sampling calorimeter (20 to 40
layers) Corresponding to about 1000 to 3000 m2
of silicon detector The pad size would be from
0.5 to 1 cm2 (in the region of the Molière
radius ) Overall it means about 30 Million
channels !!!!
NEW order of magnitude for calorimeter
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Silicon detector for HEP - Cost evolution
Moore's Law for Silicon Strip Detectors
ECAL
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Wafer size
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Compilation from H.Sadrozinski (UCSC)
ATLAS
cost/area (/cm²)
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Used in the TDR
CMS
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2/cm2
Blank wafer price 6''
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YEAR
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HCAL
ECAL
TPC
MODULE
tungsten
Detector slab
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Prototype overview
Global view of the test beam setup
VME/
ECAL general view
HCAL
2nd structure (21.4mm of W plates)
3rd structure (31.4mm of W plates)
180 mm
BEAM
VFE
ECAL
Beam monitoring
Movable table
370 mm
1st structure (1.4mm of W plates)
370 mm
Silicon wafer
Detector slab
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ECAL W-Si. prototype in test beam in 2004 ? 2005
, Where ??
Pad
PCB
VFE chip
Wafer
Transverse view
Silicon wafer (0.525 mm)
PCB (multi-layers) (? 2.4 mm)
Al. Shielding
8.5 mm
Tungsten (1.4 mm, 21.4 or 31.4 mm)
Composite structure (0.15 mm / layer)
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ECAL
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PMs
LCCAL prototype
Tiles surrounded by holder structure for PM
Fibers inside collector In front of PMs
Tiles
Si planes
LCCAL under test _at_ BTF in Frascati
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Si Pads inserted in proto 28-3-03
Lccal Si Pads design production OK Mar 03
Sensors from IET (Warsaw)

• 6 sensors /motherboard with serial readout.
• Status of production
• 16 sensors available
• 2 motherboards fully and 1 partially equipped
  (252 pads/board)

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Lccal energy resolution and linearity for Tiles
From BTF test
?E?E
Good linearity vs particle multiplicity

• Photoelectron stat. Negligible
• Sampling term 11.5 as in MC
• Uniformity of light collection still at a level
  lt 10 using all layers. Effect on resolution to
  be evaluated at next Cern TB (Aug 2003)

From Cern TB
Nphegt5.1 /layer ?Cal(45 layers) 250 MeV/Mip
800Npe/GeV Light uniformity better than 20 OK
also _at_ BTF (E 500 MeV)
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ACFA ECALKEK, Kobe, Konan, Niigata, Shinshu and
Tsukuba

• EMCAL design
• 1) Tile of 4cm x 4cm (7.1Xo)
• 2) Strip Arrays (x,y) of1cm-width
• Sub-system RD
• a) SHmaxdirect-attached APD
• and WLS-readout.
• b) Super-multi-channel photo
• -detectors.
• Present status and future plans
• 1st exp. just finished on Nov.14
• for 1(partial), 2, and a.
• 2nd exp in November 2003
• with 1(full) and b.

ECAL

• Tile/Fiber Sampling Calorimeter
• Hardware Compensation
• Design Flexibility
• Reasonable cost
• Well-established thechnology
• Sufficient granularity for EMCAL ?

Note the date
Scintillator tile of 4 x 4 cm
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HCAL
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Results from Russian groups
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The key point of the costing is the readout
electronics
The number of channels is VERY LARGE i.e. just
for the prototype, it is about 200 000 to 400 000
channels
Readout Board proposed by LLR (TDR 01)
Readout Board proposed By JINR-DUBNA
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IV. Design work on the electronic readout
System overview
I RPC ASIC located on the
chambers II Data concentrators
funnels data from several FE
chips III VME data collector
funnels data from several data
concentrators IV External timing and trigger
system
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Totally segmented with fine granularity best
choice would be gas detector radiator CALICE
collaboration Famous Digital HCAL
HCAL
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Details of TFS Optimisation Studies
Centre/straight WLS-fibre
Diagonal/bent WLS-fibre
No stress on fibre, fibre refl. tile
reflector

more stress on fibre, fibre refl. tile
reflector
L7.85cm
L7,85cm
L5cm
clear RO fibre to couple 1-3.5m in
detector, light attenuation lt18

• Double looped fibre
• strong fibre bend,
• most stress on fibre,
• probably ageing damages,
• fibre end fibre reflector
• inside tile gtgtgt
• special reflective coating
• needed ?

• 1.1 mm hole in center
• drilled and polished?
• could it be made during tile moulding?

L31,4cm
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The actual achieved LY for the TFS
Scintillator BC-408,
, Kuraray, WLS-fibre
3M-Super Radiant Reflector
Light yield/tile

• 22/-1.5 pe (BC-408, Aug. 2002)
• gtgt 26 (new results from ITEP)
• both Russian scintillators
• have 2/3 of BC-408 LY
• 20 more LY can be expected
• by improving polishing
• of WLF-fibre end,
• no gluing needed anymore

All together
100 reflectivity at fibre end
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ACHIEVED by the calorimeter studies in the 4th
ECFA workshop
test of the W-Si ECAL (CALICE)
France, U.Kingdom, MSU, Prague,.
test/validation of the technical problem of
integration (30 layers in 18cm) mechanical
assembly , mechanical tolerance, VFE seems in
good shape, use of amorphous silicon for AC
coupling,
test of the W-Si tiles (LCCAL)
Como, LNF,Padova,Trieste
test of the technical feasibility mechanical
assembly , mechanical tolerance, First results
in beam
test of the digital HCAL (CALICE)
ANL, IHEP, JINR, NIU, SNU , UTA,
Energy measurement wit digital device (GEANT4)
test with pad size, can we do it with RPC
(GEM), Geiger Chamber,. RPCs design,
Simulation studies (energy resolution, shower
width),
test of the tile HCAL (CALICE)
DESY,ITEP,JINR,LPI,MEPhI,Prague, KEK, NIU
homogeneity of response how to do the tile ?
fiber shape, choice of the fiber What is the
smallest size with a good S/N at MIP ? 5x5cm
(CALICE AHCAL) , 4x4cm (ACFA) , 9cm2 (CALICE
NIU) Where to do the readout ? - close (Si-pm)
- far (APD multi-anode)
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AND NOW
The road for the 5th ECFA , (2 next years) is
relatively clear

• Prototype in construction / test
• validation of technical aspect well advanced
  and will continue
• Prototype in test beam (2004 2006)
• physics results (specially the hadronic shower
  pattern in GEANT4)
• Diversity of approach interesting at this level

LEVEL of SEGMENTATION for ECAL for HCAL
TECHNICAL WAY to do it for ECAL for HCAL