Lccal: an R

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Lccal an RD project for the Electromagnetic
barrel Calorimeter
TALK SUMMARY

• Design principles
• Prototype description
• Status of the production
• Beam test results
• Future plans

Official INFN RD project, official DESY RD
project PRC RD 00/02 Contributors (Como, LNF,
Padova, Trieste) M. Alemi, A.Anashkin,
M.Bettini, S.Bertolucci, E. Borsato, M. Caccia,
P.C, C. Fanin, G. Fedel, S. Miscetti, M.
Nicoletto, M.Paganoni, M. Prest, R. Peghin, L.
Ramina, E. Vallazza ?.
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Prototype description
Pb/Sc Si

• 45 layers
  25x25x0.3 cm3 Pb
  ( 25x25x0.2 cm3 W ) 25x25x0.3
  cm3 Scint 25 Cells 5x5 cm2
• 3 Planes
  252 0.9x0.9 cm2
  Si Pads
  at 2, 6, 12 X0

Scintillation light transported by WLS s tail
fibers Cell separation with grooves in Sc.
plates with Tyvec strips inside
Coupled with clear fibers (to PM)
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Prototype (cntd)
3 Si planes

• Goal shower-shower separation
• Pad dimensionlt shower dimension
  0.9x 0.9 cm2
• Longitudinal sampling 3 planes
• Analogue RO VA hdr9c from IDEas
• Next year shower dimension reduction W absorber

Pad diode ac coupled

• Actual design
• Detector 6x7 pads
• Plane 3x2 detectors

pcb contact with conductive glue
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Production status

• Scintillator tiles
  
• 3 mm Kuraray SCSN-61 (25x25 cm2)
• 3 mm Bicron BC-408 (25x25 cm2)

Machined with vacuum plate as holder
gt50 layers produced
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• Fibres
  Kuraray 1mm d.
  Y11 300 ppm multicladding

To make the 2.25 cm radius curvature middle
temperature(500-700) oven
Face polished and aluminized by sputtering
More than 1100 fibres bended and spliced gt3 ph
e- /m.i.p./tile obtained stable in gt30 day
time
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• Si Pad detectors
• 20 detectors produced by IET (Warsaw) out of
  which 1 fully mounted and tested on beam, 7
  mounted and ready to be assembled in the
  prototype, 13 mounting in progress.

Full depletion at lt30 V ...but I_bias
increasing at gt30 V...
Si pad plane Mother Board
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Detector Assembling
45 Layers calorimeter prototype completely built
and ready for test
Fibres
grouped into 25x4 bundles making a 4-fold
longitudinal segmentation. Slots for the
insertion of the 3 Si pad planes.
Mechanical support for photodetectors almost
ready (Frascati)
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Test beam results

• Set up
• 2 planes Si m strip telescope
• 2 trigger Scintillators
• Calorimeter first segment (2X0 4 layers) read
  by PM
• 1 Si pad detector

cal
beam
e- 40 / 50 GeV p 50/150 GeV (used as m.i.p.)
CERN SPS H4
thanks to P. Weihammer
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Test beam results CALORIMETER (2.1 X0)
m.i.p. p check light output and uniformity in
Light collection Ratio signal/sigma gives lower
limit for photoelectrons
20
Nphegt5.1 /layer
45 layers cal.
gt 220 phe/m.i.p.
Good uniformity vs
position
Good uniformity vs
position
Simulated Light collection disuniformity(20)
Simulated Light collection disuniformity(20)
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Test beam results CALORIMETER (2.1 X0)
Too few layers to give Energy resolution but
enough to show e/p separation
150 GeV p
50 GeV electrons
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Test beam results Si pad detector (Energy
Measurement)
m.i.p. Signal gt4 sigmas
(coherent noise subtraction
not optimized)
50 GeV electrons
Pedestals
No saturation!
Out of detector (6.3x5.4 cm2 )
e/p behaviour clearly different
50 GeV electrons
150 Gev p
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Test beam results Si pad detector (Position
Meas.)
Correction for pad dimention not included
Position resolution lt 2mm in agreement with Monte
Carlo
10 GeV simulated electrons
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Future Plans

• Complete 45 layers prototype will be moved to
  Frascati on November 6th, low energy test beam
  will follow soon.
• High energy test beam (DESY/CERN)
• analyse two particle impact
• substitute the absorber Pb to W (next year)
• study new optical device (i.e. Multianode PM?s)

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Conclusions

• The proposed 45 layers calorimeter prototype has
  been completed
• A preliminar beam test at CERN with a partial
  set up gave reasonable and incouraging results
• Tests with the complete detector are necessary to
  answer to all questions
• Be patient for one month...

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• Delay w.r.t. Planned Schedule Main Reasons
• Scintillator tiles
• Tiles formerly produced by a commercial firm had
  mechanical problems too low light output
  Move to an internal INFN production chain
• Light output optimization
• Planning and assembly of the mechanical device
  for tile production
• Vacuum plate construction
• Tiles production
  
• Definition of the coupling method for the two
  different fibres species
• Si pad detectors (Producer problems)
• First-production detectors where affected by a
  unacceptable high I_bias