what type of radiation does strontium 90 emit
Naturally occurring strontium is nonradioactive and nontoxic at levels normally found in the environment, but Sr is a radiation hazard. Sr undergoes β decay with a half-life of 28.79 years and a decay energy of 0.546 MeV distributed to an electron, an anti-neutrino, and the yttrium isotope Y, which in turn undergoes β decay with half-life of 64 hours and decay energy 2.28 MeV distributed to an electron, an anti-neutrino, and Zr (zirconium), which is stable. Note that Sr / Y is almost a pure beta particle source; the gamma photon emission from the decay of Y is so infrequent that it can normally be ignored.