The R5222A is an external cavity low power Klystron from EMI. It was designed for X band between 8 and 10 GHz and the output power was 30 - to 70 mW and therefore suitable for local oscillator use.
This example is complete with tunable cavity. The waveguide internal dimensions are 28.5 x 12.6 mm and this is WR-112 designed for H Band between 7.05 - 10.00 GHz. The cavity assembly is 58 mm high and the overall length with klystron in place is 104mm. The waveguide flange is 48 mm square.
The adjustment knob of the cavity is part of a micrometer.
This image shows the micrometer at the right and valve retaining nut at the left. Note also the matching screw on the waveguide flange.
Looking into the base of the klystron.
Only one side of the housing has the micrometer head visible, this side is plain brass. The top of the micrometer head can be seen as the bright rectangle to the right of the top of the adjustment knob.
The output is directly to the waveguide via a square flange. The cavity is smaller than the guide and this is to improve the impedance match between the klystron and the guide. Fine matching is by the screw across the face of the guide.
The klystron retaining cap. The angled face mates with the klystron and holds it against the inner wall of the cavity.
The tube itself showing the type designation and serial number 1910. The top cap connection is the reflector.
The thin glass tube envelope is 28 mm in diameter, and excluding the B7G base pins is 75 mm tall.