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.
Alpha particles in smoke detectors Radioactive isotopes which emit alpha particles can be used in smoke detectors. The animation below shows a smoke detector with the radioisotope Americium 241 as the alpha source.