Dosimetry

Dosimetry (ionizing radiation) is a branch of applied nuclear physics, the study of which is to determine the physical quantities that characterize the impact of ionizing radiation (see ionizing Radiation) on Wednesday, and development of methods and tools for measurement of these quantities. The tasks of the dosimetry includes: measurement and calculation of doses (see Doses of ionizing radiation) in the fields of radiation sources and in biological objects (tissue dosimetry), the measurement of activity radioactive drugs and other
Dosimetry based on the measurement of ionization produced by radiation in air or gas, or on the measurement of radiation energy absorbed by the environment.
Produced by ionization of the gas environment of negative and positive ions start to move in an electric field to the corresponding electrodes, and in the chain there is an electric current, which is measured by the registering device.
Methods of measurement of absorbed energy-dense environments based on the number of physical phenomena accompanying the passage of radiation through matter. The oldest method of registration of ionizing radiation - photographic. This method was received the first information about the new form of energy. The film can be used to measure the exposure dose, since the degree black film is proportional to the absorbed energy. On reception of light (scintillation), which emit excited to ionizing radiation atoms and molecules based scintillation method. Flashes of light are registered photoelectric multiplier (see) (FEG), included in the relevant electronic circuit. Chemical method of dosimetry is to identify irreversible chemical changes that occur under the action of radiation with a substance, most commonly in aqueous solutions. In these purposes is widely used by the reaction of transformation of ferrous iron to ferric iron (ferrous sulfate dosimeter). Registration of irreversible chemical changes carried out by different physical or chemical means. All the more widespread luminescence methods of dosimetry, as under the action of ionizing radiation in some substances are hidden centres glow (luminescence), which appear at the next light (photoluminescence) or heat (induced thermoluminescence) the impact on the irradiated material. This luminescence is registered PMT. Promising is the use of semiconductors for the purposes of dosimetry Most accurate, but technically complex method dosimetry is calorimeter, consisting in direct measurement of thermal energy, which is converted in the end, the radiation energy.
Of special interest tissue dosimetry; as direct measurement of absorbed doses in a living organism is impossible, produce tissue-equivalent phantoms (see Phantoms dosimetry) human or animal, inside and measure radiation is one of the methods mentioned above.
Definition of activity of radioactive drugs used to treat tumors, the study of transfer processes and metabolism in the body and the other is by measuring the number of particles emitted by the drug per unit of time. This section dosimetry is called radiometry. Cm. also, Dosimetry monitoring Dosimeters ionizing radiation, Radioactivity, Counters nuclear radiation.