Space charge limited avalanche growth in multigap resistive plate chambers

Received: Abstract. The ALICE TOF array will be built using the Multigap Resistive Plate Chamber(MRPC) configured as a double stack. Each stack contains 5 gas gaps with width of 250 µm. There has been an intense RD this allows more stable operation of this detector. We have measured the gain as a function of the electric field and also measured the ratio of the fast charge to the total charge produced in the gas gap. It is well established that RPCs built with 250 µm gas gap have a much superior performance than 2 mm gaps; we discuss and compare the performance of 250 µm gap MRPCs with 2 mm gap RPCs to show the importance of space-charge limitation of avalanche growth.