The photomultiplier has a light sensitive electrode called the photo cathode which emits electrons when photons strike it. These electrodes are each maintained at a more positive potential and as result, additional electrons are generated at each dynode. After cascading through a series of these dynodes, the total number of electrons increases significantly from the original number created by the incident photon. This amplified signal is finally collected at the anode where it can be measured. Resolution is a property of all detectors and is generally a way of measuring their quality.
Resolution is the ability of a detector to differentiate between two objects.
For example, a telescope with good optical resolution is capable of distinguishing between two stars even if their separation angle is very small. Spectral resolution applies to frequency and is the ability of a telescope to differentiate between two signals which differ in frequency by a small amount. In astrophysics, scintillators are used to detect electromagnetic radiation. One of the most commonly used scintillating materials for detecting gamma-rays is activated sodium iodide . A scintillation is a very brief shower of minute light flashes, each flash resulting from the resettlement of the electrons in an ionized atom.