-On the MEDM screen load "data1234" as Command File. Content of "data1234":
+1 P 5.
+2 P 5.
+3 P 5.
+4 P 5.
-1 P 5.
-2 P 5.
-3 P 5.
-4 P 5.
means: use scanners #1 to #4, do first the 4 forward pass and then the 4 backward
ones (to give the wires time to cool down) at 5 turns/s = 12.500 mm/s. Warning:
lower velocity may cause the wire to melt. An error message will be edited if
the velocity is outside ]0., 6.1 t/s[. P is for PMT readout (S for Secondary
emission for scanners #5 and #6). The file is in 
gougnaud/arc2/ARC.
In pulsed mode (60Hz) use a velocity of 0.3 turn/s. You need to edit a special
file setting this velocity. On the MEDM screen update CW/60Hz, beam current
and DISPersive/ACHROmatic (for the record).
-Push "START" when ready, you can follow the operations by looking at:
-running command: the line of the "Command file" currently executed
-the cursor position of the scanners
-voltage versus position plot. The location of the 6 scanners on the MEDM window is the following:
| #1 | #2 |
| #3 | #4 |
| #5 | #6 |
The forward plot is green, the backward one is red. In case of saturation, redo the scan with lower gain (see details below). The only peak used for energy measurement is the rightmost one (H profile produced by the V wire): focus on this peak to adjust the gain, the 2 other peaks may saturate.
-the names on the top of the plots are the CEBAF device names of the scanners.
WARNING: operating at too high a beam current or too small a velocity may cause the wire to melt, with no opportunity to repare it before the next shutdown. The total travel time is about 15 s per scanner. During the travel, have a look at the beam current. If the beam trips, inquire why, correct if it was caused by the scan (set masks), and redo the scan (see details on trips below).
-Save the data (see details below).
-Print the MEDM window (see details below).
-you can plot the profile (see details below).
After the scan, check the peak (rightmost) quality: it must be compact (Gauss
curve) with a good signal/noise ratio (
5) If scan #1 and #2 are not compact:
report to MCC and make sure that the fast feedback is ON. If scan #3 and #4
are not compact: report also to MCC and make sure that the energy feedback and
the kresting are ON.
If the scan seems OK: start a field integral measurement and
report to
"saha@jlab.org"
with as much details as possible (at least the file names) for data analysis
and beam energy determination. Record the mail in the e-logbook. Don't forget
to save the files.