A PLA is a multi-employer, multi-union, pre-hire collective bargaining agreement that PLA proponents market to public and private construction owners as a tool to systemize labor relations between multiple construction trade unions and contractors on a specific construction site.
The alpha particle given off during the radioactive decay of americium-241 is absorbed by beryllium-9, producing carbon-12 and a neutron. Such devices can be used for the nondestructive testing of machinery and equipment and for other industrial applications.
Altogether, there are three major types of nuclear decay that radioactive particles can undergo: alpha, beta, or gamma decay. Each type emits a particle from the nucleus. Alpha particles are high-energy helium nuclei containing 2 protons and 2 neutrons. They're heavy and can be stopped by as little as a piece of paper.