Geiger-Muller tubes and their manufacture

A Geiger-Muller tube designed for use in an environment subjected to mechanical shock and vibration has a tensioned anode wire secured between first and second mounts located at opposite ends of the tube envelope. The wire tension is adjusted, preferably with a screwable-adjustment means which is locked in the adjusted position, so that the natural frequency of vibration of the tensioned wire does not resonate with any frequency to which the tube is subjected in use. The adjustment means may be included in the mount via which the envelope is evacuated and back-filled with the ionizable gas, and a gas-tight seal can be provided around this part of the mount for example by sealing off the gas pump tube. However the adjustment means may be designed into another part of the tube, for example using telescopic parts of the envelope whose sliding junction is made gas tight with a flexible seal. Alternatively, the desired tension may be obtained by welding the wire to the first mount, passing it through the second mount, tensioning it and then crimping it to the second mount. (Author)