RE: Contaminants in Rb-86?

[John Jacobus <crispy_bird@YAHOO.COM>]

Thanks for the reply.  We have had similar problems

with disposal of Sm-153 waste.  



The point about Rb-87 is interesting and one we have

not looked at.  The sample came from a biomedical

research lab, so we expected to see Ca-45.  However,

we may also want to consider the issue of Rb-87

contamination in the waste.



--- David Hornsey <bssdjh@bath.ac.uk> wrote:

> 

>    Came across a similar situation as cja when

> surveying some old Rb-86

> stock bottles for solid waste disposal. Significant

> activity even after 2

> years (~ 40 half-lives). Gamma spectrometry

> suggested Cs-134, and this was

> confirmed by the manufacturer (in this case

> Amersham.)  Caesium impurity in

> the target material was responsible. An n,gamma

> reaction on Cs-133

> apparently.

>    However your Ca-45 beta spectrum could be

> explained by the naturally

> occurring Rb-87 in the rubidium target which has a

> max beta energy of 0.27

> MeV similar to Ca-45's 0.25 Mev. The long lived

> Rb-87 has a 27% abundance in

> a rubidium compound so it is feasible. Never counted

> rubidium chloride in an

> LSC.

> 

>    David

> 

> University of Bath,

> Bath BA 2 7AY

> 

> -----Original Message-----

> From: owner-radsafe@list.vanderbilt.edu

> [mailto:owner-radsafe@list.vanderbilt.edu]On Behalf

> Of John Jacobus

> Sent: 30 January 2004 21:55

> To: radsafe

> Subject: Contaminants in Rb-86?

> 

> 

> We wee analyzing a mixed waste sample that we were

> told contained Ca-45, P-32, H-3, and Rb-86.  The LSC

> looked like Ca-45, however, the gamma spectrum

> showed

> Cs-134.  There were two distinct, but lines at

> 795.76

> and 604.66 with an estimated activity of 0.3 nCi. 

> The

> only idea I had is that there is a contaminant in

> the

> target material used to make the Rb-86.  (We have

> see

> Eu-154 contaminants in Sm-153 waste do to the

> bombardment of the target material.)

> 

> Has anyone else seen or knows about the Rb-86?

> 

> =====

> +++++++++++++++++++

> "I have sworn upon the altar of God, eternal

> hostility against every form of

> tyranny over the mind of man."

> Thomas Jefferson

> 

> -- John

> John Jacobus, MS

> Certified Health Physicist

> e-mail:  crispy_bird@yahoo.com

> 

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=====

+++++++++++++++++++

"I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man."

Thomas Jefferson



-- John

John Jacobus, MS

Certified Health Physicist

e-mail:  crispy_bird@yahoo.com



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