Operators: seely vziskin ----
The atomic fraction was measured (more on that later).
As it turned out the O2 was not set back to 0.05% when the nozzle was cooled down. I did not notice this and when I did it was too late. The nozzle froze. I had to ask for an access and warm it up. "Luckily" this warm up coincided with a crowbar in the accelerator. So little running time was lost due to the nozzle freeze. Right now I'm running unpol H2 while the nozzle cools back down.
The wirechambers are very caprisious today. I had to set WC L21 down to 3700 to avoid constant trips. However, WC L6 is now tripping so often that it renders data taking unbeareble, especialy for a single person on shift.
On the issue of atomic fraction. This time I actualy measured the effieciency of MFT 2-3 transition (albeit w/o BLAST field). Here are the results:
mass1 mass2
MFT on 4.35 4.9
MFT off 7.01 5.9
Now, by making simple assumptions, like the mass2 signal from background is the same with MFT on and off and mass2 from reconbination dropping by the same factor as mass1 when MFT is on I determined that the molecular contribution from background is 55.4 % and from reconbination 44.6 %. Of course this is after ice coating and regenration of the neg pumps, so it might change.
Also, from the Ion pol I estimated that the fraction of atoms of state 1 in the cell is about 80.6 % and about 19.4 % from other states, presumably state 2. Then for this holding field Pz = 0.86. And the total polrization is, thus 0.5*0.86 = 0.43. This is the best case scenario right now. This is consitant with what we see in our polarization measurement (at lest on the left side).
The biggest issue remains the left/right asymmetry. All distributions that I looked at looked very similar/normal on the left and on the right. I don't see any clear indication where the dilution on the right might be coming from. I think that the reason we have more event on the right has simply do with WC L21 being turned off or set low for majority of runs. One need to do a thorough TOF analisys for the left/right asymmetry (as if we were doing commisioning all over again).
This archive was generated by hypermail 2.1.2 : Mon Feb 24 2014 - 14:07:29 EST