What are the ghost-catching weapons called in “Ghostbusters”?

The answer is: Proton Packs

The Proton Pack is basically what happens when you shrink a particle accelerator down to backpack size and tell physics to take a lunch break. Dr. Egon Spengler, master of deadpan warnings about exploding molecules, created these nuclear-powered ghost lassos by cramming a cyclotron into what looks like a modified vacuum cleaner.

Here's the "science." Ghosts have negative "ectoplasmic" energy and the pack shoots a stream of positively charged protons that wrangle these spooky floaters like an atomic rodeo. Once you've got your ghost trapped in what amounts to a nuclear-powered game of red rover, you can steer it into a portable containment unit (those shoebox-sized traps that snap shut like supernatural rabbit cages).

Just remember the golden rule: don't cross the streams. Mixing those streams could cause every molecule in your body to explode at the speed of light. As Ray puts it, that would be "bad." Though honestly, total protonic reversal sounds marginally better than facing an angry Stay Puft Marshmallow Man.

The packs weigh about 35 pounds each and probably violated every safety code in the book. But when you're the only thing standing between Manhattan and a ghost-pocalypse, permits become more of a suggestion than a requirement.