Re: humidity sensors - visit at MBW Elektronik AG in nearby Wettingen/AG

[Claude Petitjean <claude.petitjean@psi.ch>]

Dear Sasha, dear Peter,

in the meantime, I had one more conversation with Mr. Daniel Mutter, the 
boss of  the
"MBW Calibration Ltd." firm in Wettingen and could already clear some of 
the questions
that you have raised.

The dew point mirror device 373-LX can be operated in closed circuit and 
be driven by our mass
flow controllers and pressure sensors. Only for coating the mirror with 
some humidity (i.o. to reach
more quickly the equilibrium), it might be necessary to release some 
small gas quantity.

One problem which Mr. Mutter believes they can solve is to go from their 
standard operation
(1 bar Nitrogen) to 1 bar Hydrogen and then go up to 10 bar while 
keeping the absolute calibration
under control. I informed him, that our CHUPS circulation system can run 
stably at any pressure
from 1 to 10 bar, but in the experiment next fall 10 bar operation will 
be required, of course.

The ideal time for the test at PSI seems to be the period from mid April 
to mid June 2006.
We would need to setup CHUPS with the dummy (or real?) TPC somewhere in 
the hall.
Obviously we would combine this test with the measurement of the 
residual deuterium in
our protium gas with the isotope separation column.

Sasha, if you have more technical questions, you are kindly invited to 
contact Mr. Mutter
directly by his e-mail address <daniel@mbw.ch> (or phone +41 56 426 21 
33). Much
information about the 373-LX device is available on  http://www.mbw.ch/

With best regards, yours

Claude

Alexander Vasilyev wrote:

>
> Dear Peter, Dear Claude
>
> the measurements at -90C is suitable for us. All my suspictions we can 
> close during simple test. If we will organize circulation with dummy 
> TPC and after some time when the humidity will be more or less stable 
> (2 days) and after that we have to measure the dependence as function 
> of the pressure. If we have linear dependence everything OK.
>
> I do not know the complete designg of device 
> 373. It has own flow controller and the pump. I did not understand:
> -this device return or not hydrogen in the system? Perhaps it simply 
> throw away the hydrogen?
> -I do not understand... In principle, with flow controller and pump 
> they have possibility to stabilize the pressure in the gold mirror 
> area. In this case our recalculation to 10 bar is impossible.
>
> So, main question. If they have massflow controller BEFORE the mirror 
> and low pressure near mirror this device is not suitable for us.
>
> With best regards   Sasha
>
> These questions are principle.
> -- 
> Vasilyev Alexander
>
> Petersburg Nuclear Physics Institute,
> Laboratory of Cryogenic and Superconductive Technique.