Phone Meeting: The Tantalum runs (01/09/2009)
Tiefenbach data vs. measured data
I have made a step back in my analysis and decided to look closely to all Tantalum runs for HRS-R spectrometer in order
to determine the correlation between the measured relative momenta "delta" and tiefenbach energies. My results are
shown in the following graph:
The slope of the curve is:
k = Delta_E_Tiefenbach / Delta_delta = 2.629 MeV/% \pm 0.3825 MeV/%
If we assume, that the approximative central momentum of the spectrometer is E_c = 362 MeV, than the ratio between the measured beam
energy and Tiefenbach equals:
Delta_E_Tiefenbach / Delta_E_measured = 1/E_c*k = 0.746 \pm 0.11 = 0.746*(1 \pm 15%)
This is of course not good, because the error is to big. This result also demolishes my fitting procedure where I have assumed,
that the ratio between the Tiefenbach and Measured energy is one.
From this results we can also see, that Tiefenbach did not work well for the run #21597, since the data point is more
than 6.5*sigma away from the fit.
Legend:
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Black line - LH2 runs
Red line - LD2 runs
Blue line - 12C runs
Green line - H runs
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Hall-Probe data
I have also checked, how Hall-probe data change between various runs. (The shown data were taken at the beginning of
each run (HALOG)):
Mean_B_Hall_probe = -0.1292965 \pm 1.62*10^-6
Using the LeRose's formula, this gives us:
P_c = 352.373 MeV \pm 4.415*10^-3MeV
We can observe small fluctuations in the hall probe, but it seems that the momentum of the spectrometer was set to the
same momentum the whole time. I have also checked if these fluctuations of the magnetic field are real, or are an
artefact of the electronics. Therefore I have examined how measured deltas change with the hall-probe data. I found no
trend and therefore I believe, that these fluctuations are not real.
To-Do:
1.) Do the same analysis for the rest of the HRS-R runs: H, D, C.
2.) Redo my fitting analysis using the Hall-probe data (seem more accurate) as constraints in my fitting formulas instead of the Tiefenbach data
