In gamma spectroscopy, which detector measures photon energies?

• A. Photon energies
• B. Effective dose
• C. Occupational dose
• D. Patient dose

Answer: (A)

In gamma spectroscopy, the goal is to determine the energy of each detected gamma photon to build an energy spectrum that identifies isotopes. The detector converts the photon’s energy into an electrical signal whose amplitude (pulse height) is proportional to that energy. By collecting many events, you get a spectrum of counts versus energy, with peaks at the characteristic energies of the gamma rays. That energy information is what the detector provides.

Dose-related quantities like effective dose, occupational dose, and patient dose describe radiation exposure to people and are measured with dosimeters, not used to resolve photon energies. So the detector in gamma spectroscopy is the one that measures photon energies, producing the energy spectrum.