Contact Health Physics at the following numbers:

Main Health Physics phone (campus hours):   (303) 492-6523
CU-Boulder Environmental Health & Safety:  (303) 492-6025
CU-Boulder Police Dispatch (emergencies or after campus hours): 911 or (303) 492-6666
Health Physics FAX:  (303) 492-1322
Health Physics electronic mail: hpl@spot.colorado.edu

Sealed source use at CU

State and federal regulations control the use of radioactive materials at the University of Colorado.  The University has been issued a license that allows the use of radioactive materials and also requires the University to control and monitor the use of these materials. The safe use of radioactive materials is best accomplished when the end user and radiation safety personnel act in cooperation

Sealed sources are radioactive materials sealed inside metal or plastic and can take many different forms.  All forms share some type of encapsulation that prevents their radioactive contents from leaking or dispersing barring tampering or a severe accident.  In some forms, the radioactive material is an inherent part of the source and cannot be separated.  Almost all "sealed sources" can be handled without concern that the radioactive material will rub-off or be dispersed onto hands or clothing.  There is, however, reason to be concerned about exposure to the radiation emitted from the sealed source.

Sealed source forms include:

Many commonly used laboratory devices also contain sealed sources, such as gas chromatographs with electron capture detectors, liquid scintillation detectors, and static eliminators.

Authorized users of sealed sources

In order to possess or use radioactive sealed sources (or devices containing sealed sources) at the University of Colorado, your Principal Investigator (or P.I., or "Licensee") must have a radioactive materials license approved by the CU Radiation Safety Committee.

To obtain a license, your P.I. must possess minimum experience and training requirements.  This training packet is one of those requirements.  The P.I. and everyone in a laboratory must satisfactorily complete the quiz associated with this packet before they begin to work with sealed sources. This training must be refreshed every three years.

By issuing a radioactive materials license to your P.I., the Radiation Safety Committee recognizes that your P.I. has assumed certain responsibilities, including assuring that everyone in the lab will have the training and equipment necessary to safely use the radioactive source(s).

The safe use of sealed sources

Sealed sources present an external radiation hazard as opposed to a contamination hazard.  Sealed sources can emit any type of ionizing radiation, including alpha particles, beta particles, gamma rays, x-rays, or neutrons.

When working with any radioactive materials, the principal concern is controlling exposure to radiation.  Since any radiation exposure presumably involves some risk to the individual involved, the level of exposure received should be worth the result that is achieved.  In principle, the objective of radiation protection is to balance the risks versus the benefits from activities that involve radiation.  Different uses of ionizing radiation warrant consideration of different exposure guidelines or means to reduce exposure.

An essential facet of radiation protection practices is the ALARA (As Low As Is Reasonably Achievable) philosophy.  The ALARA concept gives primary importance to the principle that exposure should always be kept as low as practicable.

There are several simple ways that radiation exposure can be reduced when working in the lab.  The main principles are Time, Distance, and Shielding.  Each is described below.