Scintillation counters and photographic film based detectors involve an additional step in converting radiation to electricity. A scintillation counter is often made from a crystalline material such as sodium iodide [37]. Sometimes a phosphor is also used [5, p. 166]. Incoming radioactive particles excite, but do not ionize, the atoms of the material. These atoms then decay and emit a photon. Semiconductor or other types of photodetectors convert the photons to electricity [37]. In photographic film based detectors, incoming radioactive particles expose the film thereby changing its color [37]. Materials used in the film include Al$$_2$$O$$_3$$ and lithium fluoride [153]. Again, photodetectors are used to convert the information recorded on the film to a measurable signal. Scintillation counters can be higher sensitivity than other types of radiation detectors, and they can be used to determine the energy of incoming radiation by spectroscopy [154]. The film based detectors can be worn as a ring or badge. These type of detectors are used, for example, by radiology technicians and by nuclear power plant employees. These detectors must be sent in to a lab to be analyzed, and both the amount and the type of radiation can be determined [153].