The Micro-Groove Detector

We introduce the Micro-Groove Detector (MGD), a new type of position-sensitive gas proportional counter produced using advanced printed circuit board (PCB) technology. The MGD is based on a thin kapt on foil, clad with gold-plated copper on both sides. An array of micro-strips at a typical pitch of 200um is defined on the top metal layer. Using as a protection mask the metal left after the patter ning, charge amplifying micro-grooves are etched into the kapton layer. These end on a second micro-strip pattern which is defined on the bottom metal plane. The two arrays of micro-strips can have a n arbitrary relative orientation and so can be used for read-out to obtain 2-D positional information. First results from our systematic assessment of this device are reported: gas gain > 15000, rat e capability above 10^6mm-2s-1, energy resolution 22% at 5.4 keV, no significant charging or aging effects up to 5mC/cm, full primary charge collection efficiency even at high drift fields.