A dosimeter is any device used to measure an individual's exposure to a hazardous environment, particularly when the hazard is cumulative over long intervals of time, or one's lifetime. For other uses see Time (disambiguation Time is a component of a measuring system used to sequence events to compare the durations of Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at ftudruinsubstance is lost This article pertains to a radiation dosimeter and the science of dosimetry, but other dosimeters also exist, such as sound dosimeters. Radiation dosimetry is the calculation of the Absorbed dose in matter and tissue resulting from the exposure to Ionizing radiation. A noise dosimeter (American or noise dosemeter (British is a specialised Sound level meter intended specifically to measure the noise exposure of a person integrated
A radiation dosimeter is a pen-like device that measures the cumulative dose of radiation received by the device. Radiation, as in Physics, is Energy in the form of waves or moving Subatomic particles emitted by an atom or other body as it changes from a higher energy It is usually clipped to one's clothing to measure one's actual exposure to radiation. Magnifying lenses (a low-power microscope) and an illumination lens allow one to directly read the dose by aiming the illumination lens at a light source and looking into the device.
For personal use, this is the most useful device to measure radiation, because biological damage from radiation is cumulative.
Dosimeters must be periodically recharged. One's dosimeter is usually read before it is charged, and the dose is logged, to chart one's exposure. In many organizations, possession of the recharger is limited to health physicists to prevent falsification of exposures.
A dosimeter is a very rugged form of a device called an electrometer. An electrometer is an electrical instrument for measuring Electric charge or electrical Potential difference. It has two electrodes which are charged through an external connection. Since they are the same charge, they repel each other. Electric charge is a fundamental conserved property of some Subatomic particles which determines their Electromagnetic interaction. As ionizing radiation passes between the electrodes and the electrically conductive case, the charge on the electrodes is neutralized. Image talkNew_radiation_symbol_ISO_21482svg for details --> Ionizing radiation When the charge reduces, an electrode moves away from the zero calibration. Calibration is the process of establishing the relationship between a measuring device and the units of measure The magnifier displays this motion against a scale.
The charger is a small box, usually powered by a battery. It contains an electronic circuit that steps the battery voltage up to several thousand volts. The box has a fixture that requires one to press the end of the dosimeter on the charging electrode. An electrode is an Electrical conductor used to make contact with a nonmetallic part of a circuit (e Some chargers include a light to illuminate the measurement electrode, so that measurement, logging and recharging can occur with one routine motion.
Dosimeters are made in different ranges. Peace-time occupational exposure ranges usually measure up to 500 mrem (5 mSv), which exceeds the normal US yearly dose of 360 mrem (3. The Röntgen ( roentgen) equivalent in man or rem (symbol rem) 6 mSv). War-time fallout meters measure up to 500 rem (5 Sv), roughly the lethal dose.
A similar device, used with the same charger, is a rate meter. This is an inexpensive method for civil defense persons to measure radiation rates. One measures the rate of change of the rate meter for a timed exposure after charging the rate meter. Usually one measures heavy fallout of a thirty-second period, and light fallout over a ten-minute period. The rate meter has two internal scales that read the radiation flux directly in rems for each period.
An inexpensive alternative to the electronic dosimeter is the film badge dosimeter, a plastic badge containing a small piece of photographic film. The film badge dosimeter, or film badge, is a Dosimeter used for monitoring exposure to Ionizing radiation. Plastic is the general common term for a wide range of synthetic or semisynthetic organic solid materials suitable for the manufacture of industrial products This article is mainly concerned with Still photography film For Motion picture film please see Film stock. Radiation exposure gradually exposes the film, which is periodically removed and developed, and the developed film's optical density correlated to a cumulative dosage measurement. In Optics, density is a unitless measure of the Transmittance of an optical element for a given length at a given Wavelength λ: Another inexpensive passive dosimeter is the thermoluminescent dosimeter, which contains a small crystal (typically lithium fluoride or calcium fluoride) which absorbs gamma or neutron radiation and is heated in a specialized reader to determine the applied radiation dose. A thermoluminescent dosimeter, or TLD is a type of Dosimeter. Lithium fluoride is a Chemical compound of Lithium and Fluorine. Calcium fluoride (CaF2 is an insoluble Ionic compound of Calcium and Fluorine.
See also
- Geiger counter
- Scintillometer
- Richard R. Rosenthal. A Geiger counter, also called a Geiger-Müller counter, is a type of Particle detector that measures Ionizing radiation. A Scintillometer is a Scientific device used to measure small fluctuations of the Refractive index of Air caused by variations in temperature humidity Richard R Rosenthal, MD (born April 5, 1939) is an Allergist and immunologist practicing in the Washington D
External links
Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic