hsuri wrote:
"A thin cylindrical tube which glowed when it sensed radiation."

An ordinary fluorescent tube fits the description and hsuri may already
have one.

A neon tube also readily glows in the presence of r-f.

At a radio station where I worked in 1949, I used to grab any old
fluorescent tube at night to serve as a flashlight when making checks
outdoors. It worked well when the envelope was held near one end and
reguired no antenna nor hand contact with any terminal. Frequency of the
station was and still is 790 KHz.

Best regards, Richard Harrison, KB5WZI