In the subsurface environment, muon capture by 40Ca becomes more important. The production rates are about 4200 atoms 36Cl/yr/mole 39K and 3000 atoms 36Cl/yr/mole 40Ca, due to spallation in rocks at sea level.
In the subsurface environment, muon capture by 40Ca becomes more prevalent. The production rates for 36Cl are about 4200 atoms per year per mole of 39K and 3000 atoms per year per mole of 40Ca due to spallation in rocks at sea level.