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24 May 2013

Answer to Question #1481 Submitted to "Ask the Experts"

Category: Radiation Basics

The following question was answered by an expert in the appropriate field:

What are the half-value layer measurements for steel, paraffin, and aluminium when using a 1.03 mCi sample of ⁶⁰Co?

Please refer to Ask the Expert Question and Answer 1074 for a Web link to an online reference of absorption coefficients which can be used for calculating half-value layers (HVL) for exposure reduction. Gamma-absorption data for paraffin wax is not listed in anything that I have so I calculated it as solid paraffin wax composed of 2 hydrogen atoms per carbon atom with a density of 0.9 g/cc. (Solid paraffin will have a composition of C_nH_2n+2 with n > 19 when solid at room temperature.) The results follow:HVL (cm) for ⁶⁰Co (approximate)

Iron: 3.8 cm
Aluminum: 10 cm
Paraffin: 30 cm

Robert L. Coleman
Oak Ridge National Laboratory

Answer posted on 9 January 2002. The information and material posted on this website is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Website. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.