1. The problem statement, all variables and given/known data A radioactive source which is known to emit gamma rays only at a single energy is placed in front of a gamma ray detector. The gamma ray pulse height spectrum shows three distinct pulse heights of 7.38,6.49 and 5.60 volts. What is the energy of the gamma ray? 3. The attempt at a solution From what I know, the pulse recorded should be the energy of the gamma ray emitted from the source. If that is the case, how is it possible to record three pulse when the source can only emit gamma ray of one energy? Is there something wrong with my understanding of the pulse height spectrum?