User name R. Michaels
Log entry time 20:38:26 on July20,2005
Entry number 148765
keyword=Runs with new beam shot.
Beam was adjusted to give a supposedly better entry angle
and bisect the angle between spectrometers.
BPM4A at (X,Y) = (1.55, 0.03)
BPM4B at (X,Y) = (-1.26, 0.07)
Start run 2178. We've been on C12 target since run 2176
and this run is also with C12.
The raster has been off.
Rates now (this is read online from xscaler):
T1 = 54 kHz
T2 = 5.3 kHz
T3 = 50 kHz
T4 = 4.8 kHz
T5 = T6 = 0
T7 = 88 kHz
T8 = 58 kHz
From T1-T4 rates, there is a small hint that the rates became
more equal -- but the comparison needs to be made carefully offline.
But ... see below for a first attempt !
Turn on raster 2x2 (set point 3.8x4.75) and ask for 0.5 uA.
Have not changed momentum yet.
Run 2179 : spot++ check.
Insert He4 target.
Run 2180 : He4 target at nominal momentum setting.
While waiting and bored, here are rates for run 2177 vs 2178
before/after the beam movement. This is based on the ~100
scaler events and the precision as rather good (probably < 0.1%)
using scaler package of Podd analyzer.
T1 = 58.83 kHz
T2 = 5.937 kHz
T3 = 45.63 kHz
T4 = 4.222 kHz
Note: T1/T3 = 1.29 and T2/T4 = 1.41 (i.e. R-arm higher rate by
29 to 41 %).
T1 = 53.93 kHz
T2 = 5.237 kHz
T3 = 49.56 kHz
T4 = 4.841 kHz
Note: T1/T3 = 1.09 and T2/T4 = 1.08 (so, R-arm higher by 8 to 9%).
Therefore the two spectrometers became more equal in rate,
as we expected/desired.
And ... here are rates for run 2180 (Helium run)
T1 = 293 kHz
T2 = 50.6 kHz
T3 = 280 kHz
T4 = 53.2 kHz
T1/T3 = 1.05 T2/T4 = 0.95 -- i.e. the same within 5%.