Unless I'm misunderstanding what you're saying, that wouldn't be pseudo-random; cosmic-ray arrival times are random * (in the sense that we don't have a formula

Unless I'm misunderstanding what you're saying, that wouldn't be pseudo-random; cosmic-ray arrival times are random * (in the sense that we don't have a formula for finding their arrival times). * Unless you can figure out where cosmic rays come from and model their propagation mechanism accurately, in which case you'll solve some long-standing astrophysics questions.