RE: Contaminants in Rb-86?

[David Hornsey <bssdjh@BATH.AC.UK>]

   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?



=====

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"I have sworn upon the altar of God, eternal hostility against every form of

tyranny over the mind of man."

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-- John

John Jacobus, MS

Certified Health Physicist

e-mail:  crispy_bird@yahoo.com



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