H1 LUMI system components and tasks


Electron Tagger (ET)

49 channel's crystal Cherenkov calorimeter Total transverse size = 154 x 154 mm Depth = 20cm (22 radiation lengths, X0) Position in the tunnel: z=-33.4m

Photon Detector (PD)

25 channel's crystal Cherenkov calorimeter Total transverse size = 100 x 100 mm Depth = 20cm (22 radiation lenghts, X0) Position in the tunnel: z=-103.1m

Veto Counter (VC)

A water Cherenkov detector, readout by 2 PM thus giving 2 channels: spectrometric channel (nominal HV) and veto channel (increased HV) Length along the beam = 28cm (1X0) Position in the tunnel: z=-102.8m

Second Electron Tagger (ET44)

Fully analogous to ET, but 6 channels only (2 x 3 crystals) Position in the tunnel: z=-43.2m

Third Electron Tagger (ET08)

SpaCal type electromagnetic calorimeter Position in the tunnel: z=-8.0m

Lumi System Tasks

a) measure the luminosity without dead time b) tag photoproduction (Q^2 < 0.01GeV^2) c) measure hard photons from the initial state QED radiation in DIS

How the system works

can be illustrated by the graphical example


Last update: 18.09.1998 by SL