Dear Sacha, Marat and Peter,
Brendan has performed first analyses of the run10 capture
and lifetime data for the humidity fillings. He gets
consistent results, but the required transfer rate
is 2x larger than expected from Francoise's independent
measurements. Or our experimental humidity is 2x
what we get from reading the humidity sensor.
Our best measurement were done at 2.5 ppm humidity concentration,
the HS should be accurate to 10% for these high concetrations.
The results are roughly consistent with our run9 observations.
We have been discussing many explanantions without success.
So let us check the most trivial ones:
i) I have attached a spread sheet with the temperature versus
molecular water concentration curve for our humidity
sensor. One curve uses the company's curve, another
one the parametrization which I got from Peter II. They
nearly agree.
ii) I interpret that vppm (in the Kahn manual) means molecules
per volume (not atoms?).
iii) The second step consists in converting the mA current output
of the sensor to temperature. I read in the manual that
different conversions between mA and temperature can be
defined in hardware for the sensor.
Could you please descrive exactly how you do the
conversion from current to temperature and what settings
the HS is on.
I will send this imformation to the company and have them
check it.
An error is unlikely, but we should be sure that we did not
miss a factor of 2 somewhere.
With best greetings
Peter
Attachment:
ice.xls
Description: MS-Excel spreadsheet