Results of long-term performance and subsequent laboratory tests of RPCs of the L3 forward-backward muon spectrometer

The RPC chambers in the L3 forward-backward muon spectrometer have been operational from 1994 to the end of LEP running. After dismantling of the L3 detector some of the RPCs modules have been transported to Napoli where their performance has been re-measured with cosmic rays. Results of long-term performance in the LEP environment and of laboratory tests with cosmic rays will be presented. One of the 20 tested chambers, the one with the worst performances, was opened. The chamber was inspected with microscope and also a chemical analysis of the oil coating was performed. We will report in detail about this analysis