DELPHI Elias Coniavitis KarlJohan Grahn Mzsi Kiss Tomi

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DELPHI Elias Coniavitis, Karl-Johan Grahn, Mózsi Kiss, Tomi Ylinen, Sep. 12, 2008

DELPHI Elias Coniavitis, Karl-Johan Grahn, Mózsi Kiss, Tomi Ylinen, Sep. 12, 2008

Introduction • DELPHI: DEtector with Lepton, Photon and Hadron Identification • Located at LEP

Introduction • DELPHI: DEtector with Lepton, Photon and Hadron Identification • Located at LEP in cavern 100 m under ground (present LHCb site, point 8) • Constructed 1983– 1988, operative 1989– 2000 • General purpose 4 -detector, emphasis on particle identification, 3 d-information, high granularity and precise vertex determination

DELPHI Hadron Calorimeter (HCAL) Forward Electromagnetic Calorimeter (FEMC) High-density Projection Chamber (HPC) Small Angle

DELPHI Hadron Calorimeter (HCAL) Forward Electromagnetic Calorimeter (FEMC) High-density Projection Chamber (HPC) Small Angle Tagger (SAT), Very Small Angle Tagger (VSAT) 10 m

High-density Projection Chamber (HPC) • Uses time-projection principle, measures 3 d-charge distribution induced by

High-density Projection Chamber (HPC) • Uses time-projection principle, measures 3 d-charge distribution induced by EM- and hadronic showers • 18000 electronics channels, 4 mm granularity along z, 1 resolution in azimuth, nine-fold radial sampling (over 18 X 0), dynamic range up to 50 Ge. V • Uses the lead converter as electric field cage the ionization charge of showers and tracks is extracted onto a single proportional wire plane at one end of each HPC module • Converter: 41 lead walls separated by 8 mm gas gaps

High-density Projection Chamber (HPC) Proportional Chamber R E =100 V/cm (80% Ar, 20% CH

High-density Projection Chamber (HPC) Proportional Chamber R E =100 V/cm (80% Ar, 20% CH 4)

High-density Projection Chamber (HPC) High granularity in z due to time projection

High-density Projection Chamber (HPC) High granularity in z due to time projection

Forward Electromagnetic Calorimeter (FEMC) • Two 5 m diameter end-cap discs, 9064 lead glass

Forward Electromagnetic Calorimeter (FEMC) • Two 5 m diameter end-cap discs, 9064 lead glass block counters • Cherenkov light viewed by Hamamatsu phototriodes • Homogeneous calorimeter (non-sampling)

Hadron Calorimeter (HCAL) • • Sampling gas wire chamber detector in barrel and end-caps

Hadron Calorimeter (HCAL) • • Sampling gas wire chamber detector in barrel and end-caps Barrel has 24 sectors, 5 cm iron plates in each sector End caps have 19 layers Contains about 19000 detectors 10% Ar, 60% C 02, 30% i-butane

Resolution • Energy resolution: stochastic, noise, intrinsic:

Resolution • Energy resolution: stochastic, noise, intrinsic:

Advantages / Disadvantages • Exceptionally high spatial granularity in 3 d • Precise tracking

Advantages / Disadvantages • Exceptionally high spatial granularity in 3 d • Precise tracking allows detection of EM showers and their separation from hadrons even in the complex event topologies encountered at LEP • HPC is slow due to drift time (of the order 1 s) • Multiple gas detectors (including tracker) complicated handling • Poor energy resolution