Results from development of glass RPCs at TIFR 
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Glass Resistive Plate Chambers (glass RPCs) were chosen as possible
detectors for the proposed Indian neutrino experiment. Major efforts are
currently underway to develop and study these detectors. We have developed
many detectors of dimensions 30 cm X 30 cm and 120 cm X 90 cm. We have
studied their performance in terms of their efficiency for detecting
minimum ionising particles (i.e. Cosmic ray muons), timing resolution,
cross-talk between pickup strips, performance with different gas mixtures
etc. We have developed considerable infrastructure and procedures for
fabrication as well as for characterising these chambers.

A gas mixing and flow control unit, which is capable of working on four
component gases has been designed and developed. An electronic gas bubbler
was developed to monitor the gas flow through the detector under test.
Various jigs and procedures for glass RPC development have been designed.
These include jigs for RPC assembly, graphite resistance measurement and
procedures such as coating of glass electrodes with graphite powder etc.

A Cosmic ray test stand comprising of six scintillator paddles of
different dimensions has been developed for testing and characterising the
glass RPCs. A data acquisition system based on NIM/CAMAC electronics that
supports generation of Cosmic muon trigger as well as recording of ADC,
TDC, counting rates and other information from the glass RPC detectors on
trigger, has been developed.

The infrastructure mentioned above, fabrication and testing of the glass
RPCs will be discussed. Results obtained from these studies and problems
faced during this development work will be reported.