Resident particle physicist James Maxwell ain't afraid of no ghosts -- as well he shouldn't, because he helped design "Ghostbusters'" proton packs.

A new behind-the-scenes featurette for the upcoming film explores the science that went into the design of the film. Maxwell, a senior post-doctoral associate at MIT, was on hand to give the crew direction when it came to incorporating real-life technology in the film's set work.

Opening July 15, “Ghostbusters” also stars Chris Hemsworth (who’s featured briefly in the footage), Andy Garcia, Michael K. Williams, Matt Walsh and Neil Casey, with cameos by franchise veterans Dan Aykroyd, Bill Murray, Ernie Hudson and Sigourney Weaver.