Pocket dosimeters

Since 1925, The International Commission on Radiation Units and Measurements at Bethesda, Maryland has been publishing reports updating the definitions and units for measurements of various radiation-related quantities. Of these ICRU Reports, special mention may be made of reports no. 19 (1971) [radiation quantities and units], 33 (1980) [radiation quantities and units], 36 (1983) [microdosimetry], 47 (1992) [thermoluminiscent dosimetry], and 51 (1993) [radiation protection dosimetry]. A succinct description of various devices used in dosimetry, such as ionization chambers, chemical and solid-state dosimeters, and personnel (pocket) dosimeters, will be found in Spinks and Woods (1990). In this section, we will only consider some chemical dosimeters in a little detail. For a survey of the field the reader is referred to Kase et at, (1985, 1987), McLaughlin (1982), and to the International Atomic Energy Agency (1977). Of the earlier publications, many useful information can still be gleaned from Hine and Brownell (1956), Holm and Berry (1970), and Shapiro (1972). 

For the supeiwision of the persons working in radiochemical laboratories, pocket dosimeters (generally ionization dosimeters) and film dosimeters are used. The lower detection limits of these dosimeters vary between about 1 and 40 mR. Furthermore, hand foot monitors are installed near the exit of the laboratories, by which external contamination can be detected. In the case of suspected internal contamination, the person is checked by means of a whole-body counter which allows detection of y-ray emitters with high sensitivity. The presence of natural contributes essentially to... 

B. Pocket dosimeters provide direct-reading capability that allows the dosimeter to be read at any time while working in a radiation area to get an estimate of the exposure received. The pocket dosimeter shall be read and doses recorded daily in the utilization log. If, at any time, dosimeters read off scale, an emergency situation is considered to exist and the individual s TLD badge and the control badge must be submitted immediately for processing. 

IM-143/PD. The IM-143/PD Series Dosimeter is a tactical, self reading, total dose pocket dosimeter used to determine the total accumulated dose of gamma radiation. 

IM-9. Reads from 0-200 mR gamma. It is a "Quartz-Fiber, self-indicating, pocket dosimeter. 

All people engaged in radioactive work are required by law to be registered as radiation workers. Maximum permitted radiation doses for radiation workers are prescribed by the International Atomic Energy Agency and are monitored by film badges and pocket dosimeters or TLD. At all times the ALAR A principle (i.e., as low as reasonably attainable dose) applies to any person working with radioactivity. 

Ionization Dosimeters Both of the two previous types of dosimeters require processing in orderto be read. The two most common types of ionization dosimeters can be read immediately, although the indirect type requires an auxiliary reading device to do so. Ionization dosimeters to be used as personnel dosimeters are typically about the size of a pen and are usually called pocket dosimeters. 

AR556 8.4 Direct-reading and indirect-reading pocket dosimeters, ML003739448, February 1973. 

Radiation standard found in 29 CFR 1910.1096. Employers must supply appropriate personnel monitoring equipment such as film badges, pocket chambers, pocket dosimeters, or film rings. 

Survey means an evaluation of the radiation hazards incident to the prodnction, nse, release, disposal, or presence of radioactive materials or other sources of radiation nnder a specific set of conditions. When appropriate, such evaluation includes a physical survey of the location of materials and equipment and measurements of levels of radiation or concentrations of radioactive material present. Every employer shall supply appropriate personnel monitoring equipment, snch as film badges, pocket chambers, pocket dosimeters, or film rings, and should ensure the use of such equipment by exposed employees. Personnel monitoring equipment means devices designed to be worn or carried by an individual for the purpose of measuring the dose received. 

Dosimeter—Small portable instrument (such as a film badge, thermo luminescent dosimeter, or pocket dosimeter) for measuring and recording the total accumulated dose of ionizing radiation a person receives. 

The personal portable (pocket) dosimeter usually contains a gas-filled or a semiconductor radiation detector (e.g., a G-M tube) tailored with an electronic device and a dedicated... 

Demonstrations and practical exercises in the use of survey meters, self-reading pocket dosimeters, and anti-contamination clothing. 

Whenever someone tours the Reactor Lab they must be issued a MYDOSE digital pocket dosimeter (available in the reactor console) and signed in on the visitor log. The MYDOSE pocket dosimeter will read out the total integrated dose acquired since it was turned on. For large groups, at least one member must be issued one of these dosimeters. The pocket dosimeters only detect Gamma dose. 

Figure 13.4 Individual dosimeters. These are some of the devices used to measure the exposure dose received by a worker. Front, ring dosimeter second row, dosimeter film third row, film badge holders—empty, open, and loaded with film back row, pocket dosimeter and charger/reader.

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