The proton pack is a fictional energy-based capture device, used for controlling and lassoing ghosts in the Ghostbusters universe.

[2] The proton pack, designed and built by Dr. Egon Spengler, is a man-portable cyclotron system (and indeed Dr. Peter Venkman refers to the proton packs in one scene as "unlicensed nuclear accelerators"),[3] that is used to create a charged particle beam—composed of protons—that is fired by the particle thrower (also referred to as the "neutrona wand").

The Real Ghostbusters also made proton packs less efficient with power cells, allowing them to run out of energy when appropriate for dramatic tension.

[7] For the 1997 animated spinoff Extreme Ghostbusters, the proton packs and ghost traps are redesigned to combat the threat of the malevolent Achira, an ancient disease-provoking entity accidentally released by workers constructing a new subway tunnel.

Egon, with the help of Roland, Kylie and Eduardo, increased the proton packs' nuclear capability (to deal with Achira and other subsequent enemies, much stronger than what the original Ghostbusters had faced) and modified the power system; now, the packs required replaceable proton canisters to be loaded in for them to function.

The IDW comic also shows a proton pistol attachment to the movie pack being used by Winston while hunting down Slimer.

As the Ghostbusters cross the streams, the combination of that much energy closes the door to Gozer's dimension and severs its ties to our world.

In the extended version of the reboot film Ghostbusters (2016), shows that its iteration of the Ghostbusters (Abby Yates, Erin Gilbert, Jillian Holtzman, and Patty Tolan) had initially tried to close Rowan North's portal with their crossed streams before resorting to use their Ecto-1's reactor to detonate an explosion to create the total protonic reversal powerful enough to seal it.

Later, the Ghostbusters again crossing their proton streams against Gozer to counter its energy-based powers and to weaken its physical form, allowing them to capture the deity in their 198 ghost traps.

The hero prop packs were made of molded fiberglass shells on aluminium backplates (or "motherboards") bolted to military surplus ALICE frames.

The proton packs used in stunt scenes were lightweight foam rubber versions made from the same mould that lacked the electronics of the hero props.

The original GB1 props would appear in close-ups, the mid-grade in other scenes, and new rubber "stunt" packs were made for whenever the actor needed to take a fall.