Meeting No. 22
External radiation corrections
I have completed the analysis of various elastic data, to estimate the
missing multiplicative factor in the Mo-Tsai external radiation
correction formula.
a.) I analyzed Lupolen data at 450MeV, where spectrometer B
was used in the measurement. Results of this analysis are
gathered in the previous meeting.
b.) I analyzed also 195MeV data with spectrometer A. However,
here the results are senseless. The simulation does not
work well here. Hence, I had to subtract carbon data (smeared for additional
factor) to obtain only Hydrogen data. Then I compared the Hydrogen
data to the Hydrogen simulation. I believe that this part
of the analysis is not good enough. Furthermore, at low momenta
I seem to have a problem with spec-A optics.
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c.) I analyzed elastic ISR data with spectrometer B. Here all
data indicate a missing multiplicative term greater than 1.
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d.) I analyzed elastic ISR data with spectrometer A. The high momentum
settings at 330MeV and 495MeV indicate the same discrepancy. However,
the results at 195MeV are not nice. Again, I think this is due the
problems with the spec-A matrix.
3.) 
All the results are gathered in the following plot. The
average value shows, that we are missing something. Furthermore,
Lupolen data and Hydrogen data have very different thicknesses
and densities and they exhibit the same dependence.
4.) 
The same phenomenon could be observed also in the Jan Friedrich's (see his
PhD thesis) data as well as in the Jan Bernauer data. Last year
we did a short analysis with Adrian and the discrepancy is clearly visible:
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I would like to show these results to Marc. Maybe he knows for a possibility,
where the existing formula could be improved. Since jan Friedrich also expressed
his concerns about this, I believe, we could squeeze a small publication out of
it?! What do you think?
New experiment:
a.) After discussing with Soeren, we agreed that it will be better to
have more than one plastic target. Hence, based on drawings of Micha, I will
design a new ladder that can take 9 targets. It will be ready for the
workshop next week.
b.) We need to by a new plastic foil!
c.) Micha discussed with Werner, and we can get beam on 10.-13.2. Ie, weekend,
which to me sounds even better.
Optics for spectrometer B
As discussed last week, I moved the momentum of the problematic setting up a bit
(approx. 0.15MeV) and now the "intrinsic" results look much better. I am now
redoing the full analysis. This will take approx. 14days. In meanwhile I can
start writing paper.
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Last modified 20.1.2017
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