| 摘要 |
PURPOSE:To facilitate manufacturing and to prevent the generation of noise pulses due to vibrations by a method wherein a needle-shaped electrode having an axis perpendicular to an incidence film is used as an anode of a gas flow metering tube employed for a surface pollution detector. CONSTITUTION:A chamber 1 has a constitution wherein an incidence film 3 formed of a Mylar film with aluminum evaporated thereon, or the like, is fitted to the open side of a flat rectangular-parallelepiped box 2 having one open side, and wherein a needle-shaped anode 5 is fitted, perpendicularly to the incidence film 3, at the center of the base wall of the box 2 opposite to the film 3 through the intermediary of an insulator 4. A DC voltage is impressed on the anode 5 from a DC power source 6, while a metered gas is supplied into the chamber 1 from a metered-gas source 7 to form a gas flow therein. A radiation passing through the incidence film 3 causes the amplification of gas in the vicinity of the anode 5 in the chamber 1, which is delivered as pulses from the anode 5 and counted by a counter 9 via an amplifier 8. |
