Does it matter if aluminum absorbers are near a Geiger-Muller detector when you have a radioactive source of beta particles?

Answer 1

It does if you want to detect the beta radiation. Beta radiation, beta particles, can be stopped with a sheet of aluminum foil. An aluminum "absorber" would act as a shield to the Geiger-Müller (GM) detector and stop the beta radiation, which is really high energy electrons or possibly positrons. Placing a shield between the source of the beta radiation and the GM detector would block the radiation, thus shielding the detector from it. The detector would be "blind" to the radiation. Note that this would be effective if all you wanted to do was look at gamma rays. The gamma rays and the beta radiation would leave the source and head to the GM detector, the beta particles would be blocked by the aluminum, and only the gamma rays would make it to the GM tube to be counted. Links can be found below.