Gas-filled cell for oscillator frequency stabilisation - has tapered glass tube with surrounding insulating wire coil and waveguide connected to each end of tube

摘要

The absorption cell contains a reduced pressure gas such as ammonia for frequency stabilisation of an electric oscillator or spectrometer and has a cylindrical tube of inert dielectric material of weak dielectric losses at the absorption frequency. The tube is tapered at each end to meet axial waveguides and is surrounded by an envelope winding of copper enamelled wire. The envelope is cylindrical along its full length and surrounded by a sleeve of absorbent material such as p.v.c., which is in a coaxial conductive copper tube. The ends of the assembly are cupped by respective collar, held in place by metal rings. The position of the envelope and tube is not by two axially spaced sets of three screws each, bearing through the copper tube onto the envelope. The assembly reduces absorption of gas by the tube.