Author/Authors :
Berkhan، نويسنده , , K. and Bohm، نويسنده , , G. and Kolanoski، نويسنده , , H. and Schreiner، نويسنده , , A. and Schwanke، نويسنده , , U. and Souvorov، نويسنده , , V. and Stegmann، نويسنده , , C. and Uwer، نويسنده , , U. and Walter، نويسنده , , M.، نويسنده ,
Abstract :
The Outer Tracking (OTR) system for the HERA-B detector at DESY consists of honeycomb drift tubes with cathodes folded from Pokalon-C foil, a soot-containing polycarbonate, operating with CF4-containing drift gas. The first prototypes, exposed to radiation in HERA-B, suffered radiation damage ascribed to the Malter effect (ignition of self-sustaining discharges). We present the results of investigations of cathode surface properties and include a semiquantitative discussion of the ion-layer formation process. The achieved understanding was important for the development of a radiation-hard detector.
Keywords :
Malter effect , Honeycomb drift chambers , Cathode aging , Resistive surface layers
