RE: AW: beta's in my coffee creamer

[Arvic Harms <Arvic.Harms@npl.co.uk>]

Dear Henk,



Another possibility is phosphorescence. I guess there are (milk) proteins and fatty acid derivatives (e.g., E471 and E472) in coffee creamer, and they may phosphoresce for some time. Oils and greases may show the same effect as well.



E340 is potassium phosphate, so there is definitely some K-40 in your coffee creamer.



I guess low-level gamma spec will tell you how much K-40.



Regards,



Arvic Harms



Dr Arvic Harms

Division Quality of Life 

National Physical Laboratory

Queens Road

Teddington TW11 0LW

Middlesex

United Kingdom

E-mail: arvic.harms@npl.co.uk

Tel ++44 20 8943 8512

Fax ++44 20 8614 0488



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

> From: H. Westenbrink [mailto:h.westenbrink@amc.uva.nl]

> Sent: 12 July 2004 11:19

> To: Franz Schoenhofer; Andre Geerdink; Joop Deeterink

> Cc: frank.helk@nis-hanau.de; daleboyce@charter.net; "jin

> hardeman"@dnr.state.ga.us; "cliff blackman"@dnr.state.ga.us;

> arvic.harms@npl.co.uk; jc.mora@ciemat.es; celiar@andrew.cmu.edu;

> luke.mccormick@dhs.gov

> Subject: Re: AW: beta's in my coffee creamer

> 

> 

> Dear Franz,

> 

> The creamer sticks consisted dry milk 

> component,E340,E471,E472,carotene,glucose

> and fat (vegetable).

> I suspended the creamer in the scintillation fluid (Ultima 

> Gold). After shaking

> and a period in the dark there were two phases:  a solid one 

> (creamer) and a liquid one

> the Ultima Gold.

> If K-40 is in the creamer I must see the same pattern that I 

> see in the external standard, that I made of 1 gram 

> KaliumAcetaat + 10 ml Ultima Gold or + 10 ml H2O.

> The difference could be due to quenching.

> In my Packard counter the pattern of pulses (in cpm) I 

> counted in the energy windows:

> 0-19 ; 0-156 and 0-2000 keV.

> With K-40 the continue spectrum has pulses with an energy 

> above 160 keV.

> That's not the case here. I only see pulses in the window 

> 0-19 keV and the same amount in the windows 0-156 and 0-2000 

> keV. At the moment  the counting day is day 25 the amount of 

> activity is the same as at day 1.

> 

> Why I tested the creamer? A radiologic worker at my 

> laboratory found on the internet

> that creamer was contaminated with the isotope Sr-90.

> When you have Sr-90 you have also the daughter Y-90. Y-90 

> (Emax 2300 keV) gives with

> water cherenkov radioation with an Emax < 156 keV.

> Mixing creamer with demineralized water gives pulses only at day one.

> When it was Y-90 I should expected also pulses at day 2, and so on.

> No cherenkov - no Sr-90

> My external standard (K-40) and water gives cherenkov 

> radioation (Emax 320 keV).

> I put the bokma on ice for I agree with you, that the pulses 

> on day 1 must be

> due to luminescence.

> I will test creamer + K-40 and we will see the result.

> 

> sincerely yours,

> Henk Westenbrink

> h.westenbrink@amc,nl

> radiation safety expert

> Central B-laboratory

> AMC  Amsterdam

> 

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

> From: Franz Schoenhofer <franz.schoenhofer@chello.at>

> Date: Friday, July 9, 2004 3:10 pm

> Subject: AW: beta's in my coffee creamer

> 

> > Dear Henk,

> > 

> > I might be able to help you (I have worked for more than 25 years 

> > with LSC),

> > but I need a few informations first in order not to start with mere

> > speculations!

> > 

> > What does your "coffee creamer" consist of? Did you suspend the 

> > powder in

> > the cocktail? Is it the form I have seen, which is actually a 

> > syntheticproduct, using some calcium compounds as far as I 

> > remember and not

> > containing anything derived from milk? Or is it derived 

> from milk and

> > substantially dry milk? If the latter is the case, then you have 

> > measuredthe K-40 which is present in all milk and would be 

> > concentrated considerably

> > of course in dry milk. Obviously you use some Packard counter, 

> > because you

> > give "keV". (BTW: To call the units "keV" is an incredible wrong 

> > statementby Packard, which they have not stopped since decades: 

> > The units are "pulse

> > heights", because the same radionuclide will be measured in 

> different

> > "keV"-windows when the quench changes, but the electron energies 

> > will of

> > course remain the same.) So I guess that you have no access to a 

> > spectrum -

> > otherwise you could very easily verify this, one method being to 

> > use an

> > internal standard of K-40 and quantifying the amount. One should 

> > not forget

> > the possible contribution of C-14.

> > 

> > Secondly:

> > I suppose that "demi-water" means demineralized water. Obviously 

> > you have

> > pulses in the lowest energy region, which vanish after a day. This 

> > is a

> > clear hint that you observed luminescence - I bet a bottle of 

> > Bokma Oude

> > Jenever on it. Again if you had a spectrum you would be able to 

> > see a sharp

> > peak which would be at even lower energies than tritium. You could 

> > comparethis peak with the peak from chemoluminescence produced by 

> > adding a few

> > drops of hydrogen peroxide to the vial with your sample. For

> > Cherenkov-effect you would have to have a high-energetic beta 

> > emitter and

> > the spectrum would be significantly different from both 

> > chemiluminescenceand tritium.

> > 

> > 

> > I have some experience both with milk and unexpected luminescence:

> > 

> > In the aftermath of the Chernobyl accident I tried to shift a part 

> > of the

> > Cs-137-measurements of milk from our germanium-detectors to LSC 

> > and looked

> > at the possibility to measure it with LSC. K-40 was really 

> > disturbing the

> > measurements, but we could subtract its approximate contribution 

> > from the

> > total spectrum as long as there was enough Cs-137 present. During 

> > a visit to

> > Kiev in 1987 I tried an approach for a fast method for the 

> > measurement of

> > Sr-90 in milk by LSC, by simply mixing the milk with cocktail and 

> > analysingthe spectrum, but I had just a few hours time for that 

> > task and it seemed

> > that there were other interferences.

> > 

> > I have also done a lot of C-14 measurements in wine and spirits to 

> > determinethe age of these liquids. For spirits I used the approach 

> > to measure the

> > C-14 directly after mixing with the cocktail. In one case (spirit 

> > made from

> > rowanberry - Eberesche, Vogelbeere) I observed a really persisting

> > chemiluminescence which lasted for more than a week, declining 

> > during that

> > period.

> > 

> > Best regards,

> > 

> > Franz

> > 

> > 

> > 

> > 

> > 

> > 

> > -----Ursprüngliche Nachricht-----

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

> > [owner-radsafe@list.vanderbilt.edu]Im Auftrag von H. Westenbrink

> > Gesendet: Freitag, 09. Juli 2004 11:03

> > An: radsafe@list.vanderbilt.edu

> > Betreff: beta's in my coffee creamer

> > 

> > 

> > 

> > To my surprise I found beta's in coffee creamer, when I

> > counted a mixture of creamer and scintillation fluid (ultima gold)

> > in a LSC at 0 - 156 keV. There was a significant difference with

> > the blanc.

> > When I mix creamer with demi-water I see in the LSC at 0-19 keV

> > a significant difference with the blanc (cherenkov?). Only 

> at day one

> > 

> > Can anybody tell which isotope I see?

> > 

> > Henk Westenbrink

> > h.westenbrink@amc.nl

> > Central B-laboratory

> > AMC  Amsterdam

> > 

> > 

> **************************************************************

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> > 

> 



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