Captain's logs star date.......... we are on the mission from god.........it's dark and we are wearing sun glasses:
No beam, someone through a crow bar into the accelerator. To kill my boredom I played with the charge calibration. I set the q_loop
current to 90 mA and kept it constant. The half wave plate was out. I then flipped beam 50 times for each target helicity state (state |1>
and |3>) while waiting for 10 sec at each state each time. The charge I would expect is obviously 0.09*50*10 = 45 Coulombs the result was
following :
+/+ +/- -/+ -/-
beam gated 0 0 42.1971 42.1926
beam ungate 0 0 47.1475 48.2191
After doing this the beam did not come back so I had extra time to do the following. I set the target helicity in the state |3> and the
half wave plate was still out. I then started data taking for exactly 774 sec taken from (stop time - start time) the charge I expect
should be 69.66 Coulombs. what got was: beam gated 66.4906 and beam ungated 68.6144. So I think it is save to say that we are counting
charge resonably well.
Also, Tancredi and I found a mistake in the lrn.C that was a major factor in the false asymmetry. We need more
statistics but right false asymmetry in all bins is consistent with zero. Unfortunately the real asymmetry did not show up. I looked at
what people were doing with plotting the asymmetry and it look like the cuts were not sufficient. If one plots the "crossection" (realy
just hits in the pads) with the cuts used in the asymmetry one does not get a mott crossection back on the electron side (it looks better
on the proton side). In fact the pad 2 (?) is counting highest and there is a wierd peak at backward tofs. Anyway, maybe we are
expecting to get an asymmetry out of a pile of sh............
Also, I tried to play with the upol hydrogen mfc (mass flow controller). By playing I mean trying to set a 10 sccm mfc to 0.05 (0.5 %).
I tried to do it remotely (on computer) and localy (with the dial) on the mfc. No luck as anyone knowing anyting about these things
would tell you already. The lowest I can do is 0.08 sccms (with some impressive acrobatics). The funny thing is that the deuterium
mfc is 2 sccm full scale and it is barely used. The ligit value is quite high, 4.5*10-7 torr with is 3 times the abs flow right now.
Wang is doing his thing. I think it has something to do with reconstruction. As we are leaving they are starting to deliver beam....
good luck to next guys.
Vitaliy and Wang
=====================================================================
Vitaliy Ziskin Tel: (617)253-9209
MIT 26-547 http://www.lns.mit.edu/people/vziskin/
77 Massachusetts Ave
Cambridge, Ma
02139
======================================================================
"For long you live and high you fly
And smiles you'll give and tears you'll cry
And all you touch and all you see
Is all your life will ever be"--Pink Floyd
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