In nuclear physics, describe what the alpha, beta, and gamma decay mecha- nisms are. what is the difference between β. and β decay? what is electron cap- ture, and what other type of decay does it compete with? what is internal con- version, and what other type of decay does it compete with? what type of decay is important in pet imaging? what type of decay is important when usingc for spect? what type of decay is the first step in the decay chain begun by u? what type of decay did ernest rutherford use for a radiation source in his scat- tering experiments?