The Office of Environmental Health and Safety provides individual monitoring devices to any individual who is likely to receive, in one year, from sources external to the body, a dose in excess of 10 percent of the limits listed below. In
addition, anyone who enters a high or very high radiation area must be badged. The aluminum oxide dosimeters issued to University reactor facility personnel are effective for measuring dose resulting from exposure to high energy betas,
x-rays and gamma rays.
Total Effective Dose Equivalent . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 rem per year
Lens of the eye . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 rem per year
Skin or any extremity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 rem per year
The radiation-sensitive part of the badge consists of a thin layer of aluminum oxide and CR39 plastic. This material is enclosed in a plastic holder. The plastic holder contains a set of filters which, by attenuation of lower energy radiation, enables the reader to determine the type and energy of the radiation that was responsible for the exposure.
The following rules should be observed by all dosimeter wearers:
- The dosimeter is non-transferable. All exposures to the dosimeter are added to an individual's account as indicated by the identification code.
- The dosimeter should not be worn outside of the work environment. It is intended to monitor your exposure to radiation at work only. They are to be worn at all times when you are working with radioactive material or radiation
producing equipment. - The dosimeter indicates only the exposure at the position at which it is worn, and for that reason, should be carried on the part of the body most likely to receive the highest exposure. Exception: If you are wearing protective lead, the dosimeter must be worn outside the lead at the collar level. It is important that the badges are worn properly
at all times. If they are worn improperly (or not worn when required), the dose recorded will not be an accurate record of the dose you actually received.
If it is likely that the body may be exposed fairly uniformly, a dosimeter should be worn on the trunk of the body since the gonads and most of the blood-forming organs that constitute the principal critical organs for whole-body exposure are located in the trunk. Suitable locations are the breast pockets, lapels, and the belt. Dosimeters should be worn so that they are visible at all times, except when they are intentionally covered by a shield. This prevents unintentional shielding by clothing or by items in a pocket. In situations where the trunk of the body is shielded but the head region is not, a dosimeter should be worn on the collar to monitor exposure to the thyroid and lens of the eyes. A whole body dosimeter should not be used to monitor radiation exposure to extremities. A ring badge will be issued to you by the Radiation Safety Office for this purpose if necessary.
Extremity Dosimeters - In non-uniform radiation fields where an extremity may receive a significant exposure, extremity dosimeters should be worn as near to the point of maximum exposure as possible (e.g. finger or wrist) and should not be shielded by the extremity. Ring badges may be issued for one or both hands. Ring badges are marked with right and left hand indicators. Do not interchange them. When protective gloves are being worn while handling radioactive material, the ring badge(s) should always be worn under the gloves to prevent contamination of the badge.
- If a dosimeter is lost or damaged, the EHS should be notified immediately so that a temporary replacement
dosimeter can be issued.
- If you leave the University or wish to discontinue service, please notify EHS (2-4911).
NOTE: The dosimeter is not an indication of authorization to use radioactive material. The authorization to use radioactive material is an independent process that is initiated by the completion of applicable training and a General or Qualified User application.