Radioactive dating wiki
Alpha decay occurs when the nucleus ejects an alpha particle (helium nucleus).
This is the most common process of emitting nucleons, but highly excited nuclei can eject single nucleons, or in the case of cluster decay, specific light nuclei of other elements.
Such a parent process could be a previous decay, or a nuclear reaction.), and the process produces at least one daughter nuclide.
Except for gamma decay or internal conversion from a nuclear excited state, the decay is a nuclear transmutation resulting in a daughter containing a different number of protons or neutrons (or both).
All results were negative until he used uranium salts.
The uranium salts caused a blackening of the plate in spite of the plate being wrapped in black paper.
It soon became clear that the blackening of the plate had nothing to do with phosphorescence, as the blackening was also produced by non-phosphorescent salts of uranium and by metallic uranium.
Decay products from a nucleus with spin may be distributed non-isotropically with respect to that spin direction.
Either because of an external influence such as an electromagnetic field, or because the nucleus was produced in a dynamic process that constrained the direction of its spin, the anisotopy may be detectable.
A radioactive nucleus with zero spin can have no defined orientation, and hence emits the total momentum of its decay products isotropically (all directions and without bias).
If there are multiple particles produced during a single decay, as in beta decay, their relative angular distribution, or spin directions may not be isotropic.