Dosimeters are radiation detection devices used to record the amount of radiation received by the wearer. The two types of dosimeters routinely used are the thermoluminescent dosimeter (TLD) and the Self Reading Pocket Dosimeter (SRPD).
The TLD is normally used to obtain your official dose of record. TLDs are processed routinely at the end of each calendar quarter. Your TLD may be retrieved for special processing more frequently if necessary. TLDs are sensitive to beta, gamma, and neutron radiation.
The term Self Reading Pocket Dosimeter applies to any of a variety of devices which can be read by the wearer to determine the dose received. The SRPD is usually used as a supplemental device to aid in dose tracking during activities where elevated doses are possible.
Pocket Ion Chambers (PIC) - These are small instruments which operate on the electroscope principle. Typically, the range of PIC is 0-200 mR. This is one of the most common supplemental dosimeters used in Radiation Areas.
Electronic Dosimeters (ED) are sometimes used instead of and in addition to PICs when it is helpful to have the additional capability of dose or dose rate alarm functions. The electronic dosimeter has a broad range and is usually very accurate.
Self-reading neutron dosimetry such as neutron bubble dosimeters may be required for certain work areas. Always consult the applicable Radiation Work Permit (RWP) and Operational Safety Procedure.
Other supplemental dosimeters may be required when entering High Radiation Areas or other RWP areas.
Wear dosimetry at all times in Radioactive Storage room or in the Nuclear Physics Lab when radioactive sources are used. This includes any equipment that produces x-rays.
Dosimetry must be worn on the chest area between the waist and the neck or as directed by Radiation Safety Officer.
When supplemental dosimeters are required, wear them in close proximity (within 3 inches) to the primary dosimeter. Have your pocket dosimeter re-zeroed prior to exceeding ¾ scale.
In case of offscale or irregular reading supplemental dosimeter, or an alarm in the case of an electronic dosimeter, take proper actions. These actions include:
Secure work activities,
Alert others working in the area,
Immediately exit the area,
Notify Radiation Safety Officer.
Report lost, damaged or potentially compromised TLDs immediately (eg. the badge was inadvertently taken offsite and exposed to x-rays from a medical exposure.)