Email is possible for a longer survey, but then you’re also surveying people who might infrequently use the system. I’m thinking a very quick 3 to 5 question survey will be more useful and a truer representation of the end user experience.
I found this topic and will try adding a new popup window to the user logout process:
https://bobj-board.org/t/77828
cppwiz 
(BOB member since 2007-09-13)