Answer:
A gamma rays
Step-by-step explanation:
Gamma rays unlike beta and alpha particles releases energy and they are actual rays and not particles.
A gamma ray is form of electromagnetic radiation with no mass and charge. Its energy could range from 10KeV to 3MeV.
Its range is not definite in any medium but much longer than those of alpha and beta particles. Intensity of the rays diminishes exponentially from the source.