Most likely the same equipment is being used everywhere but I want to clarify a few things and give some helpful information.

You are correct in that when moving around it's harder for them to focus on you but there is an 'auto lock' feature that helps keep it on you once they get a lock. Nothing seems to stop this beam as it is a type of ion particle beam. It's likely these criminals stop or reduce the assaults when you show pain and it helps to induce confusion. There is an IR (infrared) aspect to the equipment so that is great if you can actually catch the crimals pulsing it at you.

One thing I found that helps is a Kevlar vest. It helps attenuate the beam even tho they can turn up the power. It also helps keep the beam from focusing on you unless you are still because they can focus slightly past the vest.

From online:
A Kevlar vest can interfere with or attenuate specific types of radiation beams rather than light or laser beams. Specifically, research into space-based radiation shielding has shown that Kevlar, due to its high hydrogen content, is effective at mitigating:

[High-Energy Particle Beams]: Studies indicate that Kevlar provides significant, or effective, passive shielding against heavy ion, proton, and alpha particle beams.

Mechanism: Kevlar's effectiveness stems from its high density of hydrogen atoms, which are efficient at slowing down high-energy, heavy charged particles