In gamma spectroscopy, which detector is employed to measure photon energies?

In gamma spectroscopy, which detector is employed to measure photon energies?

• A. Geiger-Muller tube
• B. Photographic plate
• C. Semiconductor detector
• D. Neutron detector

Answer: (C)

Measuring gamma photon energies with precision relies on detectors that directly convert the photon’s energy into an electrical signal with good energy resolution. Semiconductor detectors do this effectively: a gamma photon is absorbed in a crystalline sensor (such as high-purity germanium or silicon), creating a number of electron-hole pairs proportional to the photon’s energy. By collecting the charge from these pairs, you obtain a signal whose size maps to the gamma energy, producing a spectrum with sharp peaks that can identify specific radionuclides. This direct energy-to-signal conversion is what makes semiconductor detectors ideal for gamma spectroscopy. Geiger-Muller tubes are excellent for simply detecting radiation and counting events, but they offer poor energy resolution, so they can’t distinguish different photon energies well. Photographic plates record exposure but not a quantitative energy spectrum. Neutron detectors primarily detect neutrons, not gamma photons, so they’re not suitable for measuring gamma energies.

Measuring gamma photon energies with precision relies on detectors that directly convert the photon’s energy into an electrical signal with good energy resolution. Semiconductor detectors do this effectively: a gamma photon is absorbed in a crystalline sensor (such as high-purity germanium or silicon), creating a number of electron-hole pairs proportional to the photon’s energy. By collecting the charge from these pairs, you obtain a signal whose size maps to the gamma energy, producing a spectrum with sharp peaks that can identify specific radionuclides. This direct energy-to-signal conversion is what makes semiconductor detectors ideal for gamma spectroscopy.

Geiger-Muller tubes are excellent for simply detecting radiation and counting events, but they offer poor energy resolution, so they can’t distinguish different photon energies well. Photographic plates record exposure but not a quantitative energy spectrum. Neutron detectors primarily detect neutrons, not gamma photons, so they’re not suitable for measuring gamma energies.