If you've looked at the open source particle detector[1] you see that the "sensor" can be a reverse biased diode. Nothing very fancy. [1] https://github.com/oz

If you've looked at the open source particle detector[1] you see that the "sensor" can be a reverse biased diode. Nothing very fancy. [1] https://github.com/ozel/DIY_particle_detector https://github.com/ozel/DIY_particle_detector