Microwave ridged waveguide beam pickups

Sensitive broadband beam pickups are a prerequisite for improved stochastic beam cooling. The 2 to 4 GHz and the 4 to 8 GHz bands were of particular interest for stochastic cooling applications. This report summarizes the striking results of an investigation of ridged waveguide pickups at Argonne. An upper to lower frequency ratio of 2.4:1 is readily obtained with a ridged waveguide as compared to 1.5:1 with a standard waveguide. Wire measurements and tests at the Argonne beam test facility indicate an approximate 20% increase in gain per unit over a stripline with comparable longitudinal spacing. Another advantage of waveguide pickups is construction simplicity. The output is easily coupled to a transmission line. Descriptions of the design, construction, and results are reported.