User name R. Michaels
Log entry time 02:00:24 on June25,2004
Entry number 126754
This entry is a followup to: 126751
keyword=alignment at -2%Alignment check at -2% setting (P = 2.916)
Run 1176.
The rates are much higher on T2 and T4 now (of course)
For I_beam = 0.15 uA (+/- a lot)
T1 = 176 kHz
T2 = 18 kHz
T3 = 160 kHz
T4 = 13.6 kHz
T5 = 760 kHz
T6 = 93 kHz
First, the location of HAPPEX detector in momentum (fig 1).
Requiring a hit in detector (cut on sum of 2 PMT amplitudes)
we see L-arm extends from -20 to +20 MeV and R-arm is
DIFFERENT (a red flag ?), it goes from +7 to +35.
Second, the orientaton in X-Y. Fig 2 shows clearly the
elastic stripe and the detector (it is more clear if we
cut on hit or no hit in the detector). They are reasonably
aligned in ANGLE.
Next, the optimal momentum. The edge was judged by a zoom
on the momentum (not shown). It is the right edge of peak
as shown by a line in the fig 2.
Run ..... L-HRS ...... R-HRS
1175 .... -46 MeV .... -42 MeV
1176 .... +72 MeV .... +72 MeV
To be in the box of detector, the right edge needs to be at
......... +14 ........ +27 MeV
Therefore the correct momentum setting is (average from 2 directions)
......... 2.974 ...... 2.964 GeV
......... 275.3 ...... 274.4 septum current
We go to these settings.
FIGURE 1
FIGURE 2
