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RE: D2 measurements
Dear colleagues!
The maximum contaminant level for tritium in drinking water as given by the
National Interim Primary Drinking Water Regulations (NIPDWR) is 0.740 Bq/mL
(20 pCi/mL). The NIPDWR lists a required detection limit for tritium in
drinking water of 0.037 Bq/mL (1 pCi/mL), meaning that drinking water
supplies, where required, should be monitored for tritium at a sensitivity
of 0.037 Bq/mL (1 pCi/mL).
As far as I know a required detection limit for tritium in gaseous hydrogen
is 1000 times higher than it is in water because tritium in water form is
1000 times more toxic.
> - Could tritium labeling provide additional important information
> for the calibration?
Yes, I think so.
Tritium analysis is more sensitive. Besides we can obtain useful information
about the concentration procedure not only during calibration but while
concentrating working gas too.
Best regards,
Oleg
-----Original Message-----
From: Claude Petitjean [mailto:claude.petitjean@psi.ch]
Sent: Wednesday, November 29, 2006 18:25
To: Peter Kammel
Cc: Oleg Fedorchenko; 'Alexander Vasilyev'; 'Alexei Vorobyov'; 'Francoise
Mulhauser'; 'Malte Hildebrandt'; 'Marat Vznuzdaev'; 'Peter Kravtsov';
'Victor Trofimov'; 'Semenchuk'
Subject: Re: D2 measurements
My dear friends,
I really dont want to get back into tritium business. It would
complicate our
test measurements enormously.
Regards
Claude
Peter Kammel wrote:
> Dear Oleg,
>
> Thanks for providing accurate numbers for this discussion. I checked
> some literature on AMS and found sensitivity levels up to 10-15.
> Perhaps Claude could be so kind to check on the ETH capablities.
>
> Thus natural hydrogen for calibration is out of the question and
> we would have to use tritium labeling.
>
> Of course, the use of tritium requires a lot of care and bureaucratic
> steps and, I am sure, Claude will have more comments on this.
>
> My position would be as follows: It would be interesting to briefly
> study
>
> - Could tritium labeling provide additional important information
> for the calibration?
>
> - Could we use such low levels of tritum, that NO additional permissions
> are required?
>
> If we don't need tritum, because your calibration is working fine as
> proposed, we won't even consider it.
>
> If I am not totally off, an initial 10-13 labeling of 220 l
> corresponds to 3 picogram of tritium, a very small amount indeed.
>
> With best regards
>
> Peter
>
>
> On Wed, 29 Nov 2006, Oleg Fedorchenko wrote:
>
>> Dear colleagues!
>>
>>
>>
>> The natural level of tritium in water is about 7.4*10-6 Bq/g. It
>> means that
>> tritium atomic fraction is 6.2*10-20.
>>
>> Assuming the same tritium concentration in initial gas and that we can
>> concentrate it by a factor of 50, the maximum tritium level about
>> 3*10-18 in
>> a sample from the reboiler is expected.
>>
>> I would like to know exactly the AMS measurement sensitivity to
>> tritium but
>> I doubt whether the influence of such low tritium content on deuterium
>> measurement is possible (if only initial gas will be contaminated by
>> tritium). If you do not know the origin of initial hydrogen gas
>> (which will
>> be taken for the calibration procedure) it is good idea to check it on
>> tritium content just in a case.
>>
>>
>>
>> On the other hand perhaps it should be estimated whether tritium
>> labeling
>> (with measuring in water by Liquid Scintillation Counter method) can
>> give
>> more accurate result for concentration factor?
>>
>>
>>
>> Best regards,
>>
>> Oleg
>>
>>
>>
>> _____
>>
>> From: vasillie@googlemail.com [mailto:vasillie@googlemail.com] On
>> Behalf Of
>> Alexander Vasilyev
>> Sent: Tuesday, November 28, 2006 19:30
>> To: Peter Kammel
>> Cc: Alexei Vorobyov; claude petitjean; Francoise Mulhauser; Malte
>> Hildebrandt; Marat Vznuzdaev; Oleg Fedorchenko; Peter Kravtsov; Victor
>> Trofimov; Semenchuk
>> Subject: Re: D2 measurements
>>
>>
>>
>> Dear Peter.
>> Thanks for the carefull checking in details. It will help to avoid
>> mistakes.
>>
>> On 11/28/06, Peter Kammel < kammel@npl.uiuc.edu
>> <mailto:kammel@npl.uiuc.edu>
>>
>>> wrote:
>>
>>
>>
>>
>> iv) A significant uncertainty in your error estimation comes
>> from the AMS measurement. We are all extremely impressed by
>> the 0.2 ppm uncertainty quoted by the ETH group, but hope
>> to get more details how they achieve this, in particular
>> regarding the sample preparation.
>>
>>
>> This is the main error. Perhaps possible to minimize it. But it does not
>> depend from us.
>>
>>
>>
>>
>> v) Finally, as an aside, I was wondering whether we can check the system
>> by analyzing for tritium. I remember that AMS is extremely sensitive
>> to tritium. I am sure Oleg knows whether there is enough tritium
>> in hydrogen to be sensitive?
>>
>>
>> This is question to Oleg. But when we clean water from heavy water
>> we kill
>> TO2 at all! To my mind we do not have sensible quantity of tritium and
>> impossible to make QUANTITIVE measurements.
>>
>>
>>
>>
>> Apart from this technical remarks, let me emphasize that the deuterium
>> calibration is of key importance.
>> - It will eliminate an important systematics in the final MuCap result.
>> - Trace deuterium detection (with pdm fusion) was a main item in our
>> CRDF proposal. I am perfectly willing to give up my pdm idea, if
>> we can provide <0.1 ppm deuterium diagnostics with your proposed
>> method.
>> - It is a beautiful method, pushing the current technological limits.
>>
>>
>>
>>
>>
>>
>> So we should definitely perform this task.
>>
>> With best regards
>>
>> Peter
>>
>>
>>
>>
>> With best regards Sasha.
>>
>> --
>> Vasilyev Alexander
>>
>> Petersburg Nuclear Physics Institute,
>> Laboratory of Cryogenic and Superconductive Technique.
>>
>>
>
> Peter Kammel / pkammel@uiuc.edu
> Department of Physics, Loomis Laboratory
> University of Illinois at Urbana-Champaign
> 1110 West Green Street, Urbana, IL 61801
> Tel (217) 333-5424 / Fax (217) 333-1215
>