This also results in a photon emission. Ideally, for each trapped carrier, one photon is emitted so the measurement of all light produced is proportional to the dose received. A TLD reader is a device that heats the chips within the TLD to a temperate great enough to excite the trapped carriers, causing them to recombine and emit photons. The TLD reader is loaded with a disk that contains the TLD chips leaving the first and last slot of the disk open for background counting. TLD reading is important to the field of health physics because this detection process is used to determine the amount of radiation a person is receiving from a surrounding area.
Survey meters can detect a large range of radiation, based on the scale the meter is set on.
A Ludlum Model 5 Geiger counter , is one type of survey meter that is used to detect gamma radiation. Calibrating such a meter is very important because we must have an accurate knowledge of the amount of radiation a person is being exposed to make good decisions concerning the length of time one should remain in the presence of a radioactive source. It is also important to check all of the meter s scales. To accomplish such a task attenuators, such as lead shields, with good geometry must be used. Devices with such good geometry usually respond with a larger signal than assumed.