Instrumentation of the very Forward Region

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Instrumentation of the very Forward Region
Wolfgang Lohmann
DESY (Zeuthen)
Colorado, Cracow, DESY(Zeuthen), JINR Dubna,
London (UC), Minsk (BSU), Prague, Protvino
( IHEP), Tel Aviv Collaboration
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The very Forward Calorimeter Collaboration
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The TESLA Detector
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Functions of the very Forward Detektors

• Detection of Electrons and
  Photons at very low angle

• Measurement of the Luminosity

• Shielding of the inner Detector

• Fast Beam Diagnostics

220 cm
TDR DESIGN
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• Measurement of the Luminosity

Gauge Process ee- ee-
Goal 10-4 Precision (LEP 3.4 10-4)

• Physics case GZ for Giga-Z

Two Fermion cross section at high energy,
threshold scans

• Technology Si-W Sandwich Calorimeter

• First Simulations

Optimisation of shape and Segmantation

• Theorists are working (T. Riemann, Z. Was .)

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• Fast Beam Diagnostics

e
e-

• ee- pairs from beamstrahlung are deflected into
  the LCAL

• 15000 ee- per BX 10 20 TeV

• 10 MGy per year

Rad. hard sensors

• Technologies

Diamond-W Sandwich
Scintillator crystals
Gas ionisation chamber
Deposited energy over R and f contains
information about beam parameters
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• Detection of Electrons and
  Photons at very low angle

• Tag of two photon events

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• Detection of Electrons and
  Photons at very low angle

• essential parameters

Small Molière radius High granularity Longitudinal
segmentation

• Two photon event rejection

ee- ee- mm-
(Severe background for particle searches)
500 BX

• Electromagnetic fakes

1 from physics 2 from fluctuations
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Schematic views
W-Diamond sandwich
Heavy crystals
sensor
Space for electronics
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Proposal for a 2-year RD program
LAT (low angle)
LCAL (very low angle)

• Simulations for different technologies

• Simulations (shape and segmentation)

• Design (mechanics, alignment)

• Comparison of technologies

Choose the most promising(s)

• Physics studies

• Sensor prototyping and lab. tests

• Sensor prototyping

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The first steps .
New design of the forward region (e.g. l 4m)
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The first steps .
Diamond sensor prototype measurement (JINR and
DESY)
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Diamond sensor prototype measurement (JINR and
DESY)
Mip response using a Si sensor
First spectra using Diamond
Sr90 source
noise
First new sensor samples from Fraunhofer Institut
Freiburg and Prokhorov Institut Moscow are
expected mid april
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• Shielding of the inner Detector