Development of a Micro Pixel Chamber for the ATLAS Upgrade

The Micro Pixel Chamber(μ-PIC)isbeingdevelopedasacandidateforthe muonsystemoftheATLAS detectorfor upgrading in LHC experiments. The μ-PICisa micro-patterngaseous detector that doesn’thave floating structure such as wires, mesh, or foil. This detector can be made by printed-circuit-board (PCB) technology, which is commercially available and suited for mass production. Operation tests have been performed under high flux neutrons under similar conditions to theATLAS cavern. Spark rates are measured using severalgas mixtures under7MeV neutron irradiation, andgoodpropertieswereobservedusingneon,ethane,andCF4mixtureofgases.Usingresistivematerialsas electrodes, we are also developing a new μ-PIC, which is not expected to damage the electrodes in the case of discharge sparks.