H1 LUMI system components and tasks for HERA-II running period

Electron Tagger (ET6)
   12 channels (6 x 2 cells) SpaCal type calorimeter,
   made of lead and scintilator-fiber planes
   Total transverse size = 75.6 x 25 mm^2
   Depth = 20 cm (22 radiation lengths, X0)
   Position in the tunnel: z = -5.4 m

 Photon Detector (PD) 
   24 channels electromagnetic calorimeter, 
   made of quartz-fibre planes between tangsten absorber plates.
   Total transverse size = 12 x 12 cm^2
   Depth = 25 radiation lenghts, X0
   Position in the tunnel: z = -101.8 m

Veto Counter (VC)

   A Quartz Preshower, installed in front Photon calorimeter 
   and after berillium syhchrotron radiation absorber.
   Position in the tunnel: z = -101.4 m

Electron Tagger (ET40)
   6 channels (2 x 3 crystals) total absorption Cherenkov calorimeter,
   made of 2 x 2 cm^2 KRS_15 crystals, with a hodoscopic structure.
   Position in the tunnel: z = -40.0 m

 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