Re: RE: AW: beta's in my coffee creamer

["H. Westenbrink" <h.westenbrink@AMC.UVA.NL>]

Dear Arvic Harms,



the contribution of K-40 is with our detector

(a well crystall with a NaI(Tl) scintillator) not measurable.

No gamma no beta+.



Testing creamer with water gives 4 houres a luminescence signal.



sincerely yours,

Henk Westenbrink

radiation safety expert

Central B-laboratory

Academical Medical Centre

  Amsterdam



----- Original Message -----

From: Arvic Harms <Arvic.Harms@npl.co.uk>

Date: Tuesday, July 13, 2004 10:54 am

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



> 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 [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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