Pocket dosimeters are small ionization detection instruments that directly indicate exposure to ionizing radiation. They are commonly used in industrial radiography and are usually carried in a pocket. The two types of pocket dosimeters are the direct-reading pocket dosimeter and the digital electronic dosimeter. An auxiliary charging device is usually needed to operate the dosimeter.
The operating quantity for personal dosimetry is the personal dose equivalent, which is the dose equivalent in soft tissues at an appropriate depth, below a specific point on the human body. The dosimeter can be reset after taking a reading for recording purposes and can therefore be reused several times. It should be recharged periodically to restore the zero dose reading after exposure to radiation. We recommend an annual calibration of the direct-read dosimeter, which is generally consistent with good health physics practices.
Modern electronic personal dosimeters can provide a continuous reading of the cumulative dose and the current dose rate, and can warn the user with an audible alarm when a specified dose rate or cumulative dose is exceeded. Other dosimeters, such as thermoluminescent or film types, require post-use processing to reveal the cumulative dose received, and cannot give a current dose indication while in use. MOSFET gate oxide, which is conventionally silicon dioxide, is an active sensor material in MOSFET dosimeters. A version of the previous dosimeter without the self-reading capabilities, called a pocket ionization chamber or simply a pocket camera, was used extensively in government and military projects of World War II and post-war, particularly the Manhattan project. It is now being replaced by more modern dosimeter types, such as the electronic personal dosimeter (EPD).
Such devices are known as legal dosimeters if they have been approved for use in personnel dose recording for regulatory purposes. Pocket dosimeters are used to provide the user with an immediate reading of their exposure to x-rays and gamma rays. They are measured in Roentgens that will record your exposure to ionizing radiation. Dosimeters can be maintained in working condition by simply cleaning the eyepiece lens and load switch insulator with clean water and a lint- and pimple-free cloth. Additional dosimeters can be used to assess the dose in the extremities or in radiation fields that vary greatly depending on the orientation of the body towards the source.