The Active Photon Converter of the STORM Collaboration.

Bomben L., Bandiera L., Carsi S., Lezzani G., Mangiacavalli S., Mascagna V., Prest M., Romagnoni M., Ronchetti F., Soldani M., Vallazza E.
  Venerdì 16/09   15:30 - 19:00   Aula B - Maria Goeppert-Mayer   I - Fisica nucleare e subnucleare   Presentazione
The unique properties of oriented crystals can be exploited in order to ---among other things--- enhance the radiation produced by a high-energy electron/positron or photon crossing the crystal lattice, effectively decreasing the radiation length of the material. The STORM Collaboration intends to study this effect in different crystals, using 5-120 GeV/c electron beams. In this contribution we shall present the simulation, development and commissioning of the Active Photon Converter (APC), a detector developed by the INSULAB group and employed in the STORM beamtests. The APC will allow to estimate the average number of photons produced by a particle crossing an oriented crystal. It consists of two plastic scintillator tiles (the first acting as a veto for charged particles), readout by photomultiplier tubes and a thin ($0.2 X_{0}$) copper radiator positioned between the tiles.