Re: impurity capture

[Bernhard Lauss <lauss@berkeley.edu>]

Dear friends,


First let me apologize, that I have at this time
no time to participate in our teleconferences.
I hope this will change.


The present discussion just shows again that I failed,
when I tried to set a common language standard for
our impurity discussions with my impurity note.

Therefore, let me summarize and clarify my points again:


- I tried to define everything with respect to atomic units
in order to avoid the molecular confusion.
Consequently there is a normalized transfer rate to
oxygen which is equal independently of the molecular composition
e.g. O2 or H2O
Important all concentrations are given in atomic concentrations.


- The difference between these 2 impurity species is
naturally incorporated in the concentration of the impurity
e.g.
 if 10 ppm of the particles in an H2 O2  mixture are O2  then c_0 = 10ppm
 if 10 ppm of the particles in an H2 H2O mixture are H2O then c_0 =  5ppm
 if 10 ppm of the particles in an H2 Ar  mixture are Ar  then c_Ar = 5ppm

I believe this is the natural way of seeing the problem and I found
it confusing, if one incorporates this into the transfer rate.
If Peter wants to incoprorate the factor 2 difference in the transfer
rate, and not in the concentration, its infact the same value for (cd *
lambda) ,
but then we should agree once for good on a definition,
and not change it every once in a table.
On has just to think, when one uses partial pressures to convert it
correctly to concentrations. You don't have to do this if you follow
Peter's notation.


- The effective transfer rate O_eff, which I defined in my impurity note
does  NOT  have to do anything with this molecular/atomic issue.

O_eff is the normalized atomic transfer rate to oxygen which one needs
in order to explain the MuCAP data from run9.
Specifically, in order to explain the high impurity
capture event yield which we have observed.

The big issue in the whole discussion in the last 1/2 year was,
that in principle this Oeff should be
equal to the value given in the Werthmueller paper,
BUT IT IS AT LEAST A FACTOR OF 2 HIGHER necessary
in order to explain the MUCAP Run9 data.

This issue has not been solved yet.
That's why it was necessary to redo the 2 water flow measurements in
Run10.

MuCAP cannot explain its observed values with published
literature transfer rates from Werthmueller et al.
This does not say anything about the cause of the
difference, e.g. Werthmueller's rate values, some mistakes in our
determination or ????

However, our efficiency estimation for oxygen impurity captures,
can be excluded as cause,
as clearly there are more than 100% detection efficiency
values necessary in order to explain our observed yield with
Werthmueller's groundstate transfer rate.

  Hope this clarifies a bit the things.


       Best regards

		Bernhard