OPERATION OF MICROSTRIP GAS-CHAMBERS MANUFACTURED ON GLASS COATED WITH HIGH-RESISTIVITY DIAMOND-LIKE LAYERS

We describe recent observations and measurements realized with microst rip gas chambers (MSGCs) manufactured on borosilicate glass coated wit h a thin layer of diamond-like carbon (DLC) having a surface resistivi ty around 4 X 10(16) Omega/square. The role of the back-plane electrod e configuration and potential in the detector performance has been stu died. Even for this very high resistivity of the coatings, MSGCs opera te differently from those manufactured on bare bore-silicate glass; th e charge gain increases with the radiation flux for counting rates abo ve 10(3) Hz/mm(2), reaching a value 60% higher for 10(5) Hz/mm(2) This behavior does not depend on the presence and potential of the back-pl ane electrode; however, both maximum gain and rate capability are infl uenced by the drift field. From this study, compared with measurements realized previously with other detectors, we deduce that for stable h igh rate operation of MSGCs the resistivity of the coating should not exceed similar to 10(15) Omega/square.