When a bias voltage is applied to the crystal, incident ionizing radiation creates charge carriers that are swept toward oppositely charged contacts. Electrons are the main carriers. These crystals have lower trapping levels and are less sensitive to neutron damage. Several parameters are useful in the selection of a detector for a particular application.
Efficiency is also related to crystal size.
While a small detector may be less expensive, the expense of longer analysis times can out-weigh the extra cost. An overly large detector wastes money and may create high count rate problems. Thus, it is important to select the appropriate size. Energy Resolution Energy resolution is a measure of how well neighboring or overlapping peaks can be distinguished from one another. For lower-energy regions, the FWHM of the 5.9 keV line of 55 Fe, or the 122 keV line of 57 Co, is reported.