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Personal Electronic Dosemeters
For over 40 years , radiation workers have been wearing personal electronic dosemeters ( PEDs ), which are sometimes referred to as electronic personal dosemeters ( EPDs ), to measure their radiation dose in real time . The PED has a built-in radiation detector and shows the accumulated dose on an electronic display . Some PEDs also display the real-time dose rate as soon as the device detects radiation . Alarms can be pre-set to alert the worker of a higher than expected accumulated dose or radiation dose rate .
What are PEDs used for and how they are worn ? PEDs are used by radiation workers to measure their radiation dose . They are generally worn on a belt , via a clip or on the pocket of a lab coat . A Radiation Protection Supervisor will issue the PED and set alarms at the upper level of expected dose or dose rate . If a pre-set dose limit or dose rate is reached , the PED will alarm to warn the worker . The worker will then follow instructions provided in advance of the job on how to respond to the alarm . A button on the PED will silence the alarm .
How do you operate and set up a PED ? PEDs are generally quite complicated to switch on and set up . Buttons and displays vary , and training is required to set alarms and dose limits . However , they are simple to use once this is done ; the wearer simply reads the radiation dose on the PED and responds to any alarms .
What types of radiation do PEDs detect ? All PEDs can detect high energy gamma ( e . g . Cs-137 & Co-60 ) and low energy gamma ( e . g . Am-241 ) radiation . Some also detect beta radiation , and some special models are produced to detect neutron radiation .
What is the benefit of wearing a PED ? Radiation workers typically wear a passive dosemeter ( e . g . a Thermo Luminescent Dosemeter , TLD ) as required by regulation . These record the dose received during radiation work but do not provide a real-time indication that the wearer is accumulating radiation dose . This means that in extreme cases , a worker could inadvertently receive a life-threatening or even fatal dose of radiation . In more typical applications , the worker could be receiving dose above the expected levels . An alarmed PED gives the wearer an audible and visual warning that they are receiving a dose above expected levels , allowing them to remove themselves from the source of radiation .
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36 Radiation Protection Today www . srp-rpt . uk