Can you ID some spooky-spacey 1970s music?

I’d sure like to identify the electronic/classical/choir piece you can hear between 3:05 and 3:55 of this clip HERE

The movie is awful (although some will get a kick out of it) but more importantly I like that piece of music. I’ve heard this same piece used in several B-movies of the late 1970s and it always jumps out at me. It’s probably something public domain… but what? Any positive ID would be cool!

It sounds kind of Tangerine Dream-ish. They did stuff like that for a bunch of movies, but I don’t know about this particular example. (yeah, I know, not really an answer)