Alpha radiation does not penetrate glass. Why wouldn't an alpha emitter be used in a shield experiment against beta emitters?

Dear robo

How would you envisage alpha emitters to stop beta radiation?
Alpha radiation consists of helium nuclei, and are mainly emitted by radioactive elements, particularly those with a high atomic number.
Beta radiation are electrons (or positrons), also emitted by radioactive elements.

Bombarding an alpha emitter (i.e. radioactive elements) with beta radiation will not shield either the alpha or beta radiation, but could result in increasing the strength of both the alpha and beta radiation processes.