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Re: Humidity calibration
Dear Sasha,
your new proposal sounds much more convenient for our situation.
I called Keller AG, and got a prize tag of CHF 1200 for the
specifications below
(0.01% precision). They will send me an offer.
I think we should pursue our humidity calibration plans according to
this line.
With best regards
Claude
Alexander Vasilyev wrote:
> Dear Colleagues,
>
>
>
> before proposal about humidity sensor calibration I assumed that
> separator will finish its job this year. If not, we CAN NOT
> disassemble separator - no questions!
>
>
>
> In this case the most easy way for calibration is to use as a source
> of cold liquid nitrogen. The temperature is suitable. All
> instabilities will be corrected by the Xe pressure stabilization.
>
>
>
> So, I can start production of the independent system for the
> calibration. I hope I can use current CRDF for it (if collaboration
> agrees).
>
>
>
> 1. Vacuum chamber with liquid nitrogen volume, Cu heat bridge, Xe
> volume, H2 heatexchanger.
>
> about 1000 Eur manpower and 700 Eur materials.
>
> 2. 1 cryogenic Pt 100 - Claude has it.
>
> 3. 1 pressure sensor for Xe. We can not use pressure sensor from H2
> lines. It means we have to buy it.
>
>
>
> http://www.keller-druck.com/picts/pdf/engl/33xe.pdf
>
>
>
> If we can buy PPA 33X for 10 bar with RS485 and "extra precision"
> we can make unic measurements with absolute calibration of humidity
> sensor on the level +/-3% at 20-30 ppb.
>
> Could I ask you to get offer from Keller?
>
> 4. We will not use differential pressure sensor form the separator.
> Exist another methods to control the system.
>
> 5. Electronics from separator will control the humidity calibrator.
> Nothing new exept software (Peter's job) and cabling.
>
> 6. Job with humidity calibration will take 2 weeks of 3 persons (I,
> Marat and Peter).
>
>
>
> This job can be done in Gatchina before the end of September and in
> October in PSI.
>
>
>
> I really think that we have to do it! This method will be MORE precise
> then in the firm which produced humidity sensor. The reason is very
> simple, we have to calibrate in a VERY narrow range at OUR conditions
> (10 bar of hydrogen) with OUR electronics. Real conditions and
> electronics can produce additional errors.
>
>
>
> With best regards Sasha.
>