This is interesting. We should continue to take data with decreasing
atomic fraction (AF) for a couple of days. We should look for a
correlation of the measured asymmetry with the measured AF. Each day we
should also measure the AF and its dependence on the MFT being ON or OFF.
Does this track with lower sextupole pressure? How muc ep data do we have
to take to see a 10-15% chnage in the target polarization?
Richard
On Sun, 31 Aug 2003, Electronic Log Book wrote:
> Operators: ajmasch vziskin tavi
>
> Running beam untill 18:30. Stopped to measure the atomic fraction.
> The atomic fraction in the cell with MFT 2-3 off was measure 43 to 45 (current dependance)%. I found a MFT 2-3 resonace @ -5 Amp with the BLAST field off. With this MFT2-3 on the mass1 signal drops by about a half (current correction needed) however mass2 dropped by significantly less(less than 1/3). The atomic fraction with MFT2-3 is 39.3 % which is more consistant with the data (on that later). This indicates that there is a significant number of H2 that does not come from the recombination (otherwise H2 would also drop by a half).
>
> The data definately shows an assssymetry, with dilution factor of about 0.18 (60 and 30% beam and target respectively), with the asymmetry from latter data showing slightly lower dilution. However, the bigger issue is the left/right inconsistancy. Electron on the left asymmetry look very dissent. Electron on the right looks a lot worse. I looked into the issue further and found that my making even tighter cuts on the vertex this discrepancy seems to reduce. Upon further investigation I found the negative overall electron-right asymmetry gets diluted by mostly "positive asymmetry" comming from downstream (????). More statistics need for investigation. By comparison, electron-left asymmetry vs. vertex looks exactly like you would expect it.
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