what makes a better shielding agent for radioactive decay, polyethylene or lead?

Answer 1

It depends on the type of radioactive decay.

Alpha particles are sufficiently shielded by a piece of paper. Of course, a piece of paper is rather flimsy to work with, so you will probably want to use something stiffer. A typical alpha-emiter would be tritium (H-3).

You absolutely under NO CIRCUMSTANCES want to use lead to shield against beta emitters such as P-32. High atomic-weight materials will often absorb the beta emission, but then emit high-energy electromagnetic radiation (X-rays). In other words, you put the lead between you and your sample so you don't get a dose of beta particles, and you wind up being bombarded with even WORSE radiation. Not a good idea. If you're using a beta-emitter, go with the polymer.

Typically gamma-emitters are shielded with lead, steel, or tungsten. Working with gamma-emitters is nontrivial.

You should consult in detail with your radiation safety office before beginning any program of work with radiation. If your location does not have one, contact an affiliated program at another university or industry because the health hazards are considerable and legal requirements in most nations reflect that hazard.

Answer 2

For radioactive decay lead is a better shielding agent than polyethylene

Answer 3

Lead; because it's denser. The effectiveness of a material for radioactive shielding is directly related to its density. Of the commonly used materials for that purpose, lead is the best, concrete is second, earth is third, water is fourth.

Answer 4

Lead