A Geiger counter consists of a tube filled with ______. One end of the tube has a thin layer of material called the ______. Inside the tube is a thin ______ that runs down the middle of the tube. A high ______ is applied between the ______ and the outer casing of the tube (also made of metal). When a particle of radiation passes into the tube, it ______ the gas. Due to the voltage, the ion and electron will be attracted to either the center or outside of the tube. The overall result is that a ______ is produced, and thus the radiation can be detected.