Comment on "A double-gap π-mode klystron output cavity"

With reference to the above-named letter, the commentor reports that a complete theory of double-gap and multigap interaction in klystrons was published by Chandra and Gavin in 1964. A microwave cavity suitable for double-gap interaction in klystron amplifiers and reflex klystrons was also described by Chandra in 1964. Experimental work on a double-gap reflex klystron is in progress at the National Physical Laboratory, New Delhi, India.