halo

I'm not sure if there are any benefits 

of building a particle accelerator in space 

but it wouldn't need isolation from cosmic particles 

because there usually aren't enough cosmic particles to prevent experiments 

and if there would be too many cosmic particles for a while 

then the experiment could just be delayed for some time 

until there are fewer cosmic particles 

the simplest and cheapest idea 

could be to build to particle accelerator cannons facing each other 

with open space at some distance between them 

the particle accelerator cannons would fire particles towards each other 

then the particles would travel through open space

and then smash into each other 

then nearby devices could measure the results 

the cool thing would of course be 

to build a particle accelerator ring in space 

and then build a space station outside/inside that ring 

so that it becomes a ring habitat 

with a particle accelerator ring inside 

a few autonomous robots could be sent to the asteroid belt 

to gather material from the asteroids 

and build more of themselves 

and then the many autonomous robots 

could collect building material from the asteroid belt 

and then the many  autonomous robots 

could build a particle accelerator ring  

that method would enable the particle accelerator ring 

to become extremely large 

many technologies have dual-use capabilities