RE: Half value, tenth value layers

["Grimm, Lawrence" <LGrimm@FACNET.UCLA.EDU>]

Hi all:  I received a comment on my half/tenth value layer post and I would like to share my response.



Bill: 



I've used the Grove shielding program (www.grov.com  or www.framatone.com).  If you are doing serious shielding calculations, it is worth every penny.  Each time I used the program, built the shield, then empirically measured the dose rate, the Grove calculation was dead on the money.  Typically, I use the program when the shielding is permanent and expensive to build.  



I use half-value layers to ballpark the number when the shielding is movable, relatively cheap, and I have reason to believe I am over-shielding anyway. This latter situation occurs all the time in my researchers' labs. HVL's are a handy tool in a lot of situations. However, in the university research setting it is not uncommon to run into unlisted nuclides (in the RHH or the Shielding Compendium), and it means a fair amount of time to do the calculation. In my opinion,  HVL's have limited value as an HP tool, but they are great for ballpark estimates.   



I've never found a complete table, and it would be lovely, and time saving, if someone has one.    



Larry Grimm, Senior HP

UCLA EH&S/ Radiation Safety Division

	If this email is not RSD business, the opinions are mine, not UCLA's.



************************************************************************

You are currently subscribed to the Radsafe mailing list. To unsubscribe,

send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

radsafe" (no quote marks) in the body of the e-mail, with no subject line.

You can view the Radsafe archives at http://www.vanderbilt.edu/radsafe/