I have an old Eimac 450TH xmitter tube I keep around my shop as a
conversation item (I service pro audio gear). One of my customers who
is well versed in the mfgr of vacuum tubes says it is not really a
great idea to have it out in the open....possibility of radiation. Any
truth to this? He said to put it in a box with some unexposed camera
film for a while to see if there is any radiation activity. I've never
heard of this and the envelope is still sealed as far as I can
tell....there's no getter in these.