Latest news: Direct reading dosimeters

Reminder: Not all types of direct reading dosimeters (DRDs) are suitable for use in elevated dose-rate conditions

The purpose of a (DRD) is to accurately and reliably measure and display dose and/or dose rate to help the wearer make informed and important decisions to control radiation exposures.

Situations can vary in terms of environmental conditions and, more importantly, in terms of gamma dose-rate fields. It is the user’s responsibility to determine the environment in which the DRD will be used, and to choose a suitable DRD for all potential operating conditions based on the manufacturer’s specifications. Not all types of DRDs are suitable for use in elevated dose-rate conditions. Failure of a DRD to respond accurately and reliably may lead to a situation where the wearer may unknowingly approach or exceed a regulatory dose limit or action level.

The table below provides general information and guidance for the three types of detectors most commonly used in DRDs.

Detector type	Typical dose rate range	Advantages	Limitations
GM-tube (electronic)	0 to 20 mSv/h	real-time display alarm capability for dose and dose rate sensitive for use at low dose rates	limited high dose rate operating range
Silicon diode (electronic)	0.001 mSv/h to 10,000 mSv/h	real-time display alarm capability for dose and dose rate reliable dose response in a wide range of dose rates including upset conditions	limited very low dose rate operating range
Ion chamber (pencil)	measures dose accurately at any dose rate within the instrument’s dose scale various dose scales available	real-time display	no alarm sensitive to shock small dose scale instruments may be limiting for upset conditions large dose scale may degrade dose resolution

For further information related to DRDs, please contact your licensing specialist at 1-888-229-2672