Gas Magnification of Multi-Gap Resistive Plate Chamber

A Monte Carlo model, simulated energy deposit in six gaps of multi-gap resistive chamber (MRPC) irradiated by a 6.771Mbq ⁶⁰Co gamma source, was built in MCNP code. The MRPC primary current, which was too low to be measurable with existing instruments, only was derived from the simulation. The MRPC operation current, after gas avalanche magnifying, was measured employing a PCI-1714A/D DAQ card. The magnification factor, about (0.8±0.12) × 10⁷, was obtained when the operation gas mixture is 5.3% iso-C₄H₁₀ and 94.7% C₄H₂F₄, HV is 14kV and the counting rate is about 3Hz/cm².