Dear All,
    I had a look into the MC files Wlodek sent to me in
comparison to the data from the 3 runs processed by Kin.
The table of comparison of outer edge of the acceptance could
be found in the attachment. Units are mm. I took projection of
the central 20 mm and fit outer edges with straight lines.
Two numbers are provided - crossing of zero and crossing of the
half height. The later I believe provides better estimate.
Here are some conclusions:
1. We have a good agreement between east and west.
2. Monte-Carlo clearly shows the features expected from naive
optics (the presentation is also attached).
3. There is some numerical disagreement with naive model,
which I think can be explained by beam emittance.
4. In the horizontal plane the size of the experimental spot
is only 1.1 mm smaller than that of the MC one. While introduction
of 100 urad crossing angle into MC gives 2.0 mm. (Naive calculation
would give 2.5 mm). We will also mention here that outer edges, limiting
horizontal acceptance in the data are smooth and of the same size as in
simulations. I think that these 1.1 mm is a good estimate of the
systematic uncertainty we have in the horizontal geometry.
5. The picture is quite different in the vertical plane.
Outer edges of the data are not smooth and the size is 4.5 mm smaller.
This means that between RPs and the IP on some side we have some unknown
device limiting vertical acceptance. So we can't use the method relying
on the outer edges to adjust the geometry.
6. I would redo table 5 of the note taking into account:
- the latest transport;
- kicker effect;
- making acceptance symmetrical in X. no this step in Y.

Hopefully I will do this coming weekend. Then I think this is our best
estimate of the geometry we could have for the 2009 data.

    With kind wishes, Igor.