0. Recover after a Beam dump
1. A shutter should open automatically as soon as beam comes back. Check the same
and open the shutter if the shutter does not open automatically.
2. Wait for 45 minutes for the optics to warm up.
Protect the CCD with the Copper/Lead plate.
3. Check flux on pdbs @ att 2 and pdbs_att2
att 2;shutteroff;pdbs_att2;
Flux should be between 60 kHz and 74 kHz at samz = and respectively.
If flux is acceptable, proceed with experiment.
4. If flux is not acceptable, do the following:
{
5. att 15;counters -1 2;plotselect pind2;move_pind2z_in;att 0;shutteroff;
Check flux on pind2. Flux should be in the range of 220 - 240 kHz.
If it is, then S4 slits are fine. We need to check S2 slits.
6. To check S2 slits:
att 15;counters -1 4;plotselect pdbs;move_pind2z_out;att 7;shutteroff;
S2on;lup s2vcen -200 200 40 .1;umv s2vcen CEN;
Perform step 3 to check flux on pdbs.
}
7. If above steps do not restore the flux on pdbs, then do the following:
{
8. S4on;att 15;counters -1 2;plotselect pind2;move_pind2z_in;att 0;shutteroff;
lup s4vcen -100 100 40 0.1;umv s4vcen CEN;
Note: S4vcen may not be reproducible, maximize the counts by tweaking using
"tw s4vcen 5" (in + and - directions till you get the max. counts)
Check flux on pind2 (step 5)
9. If flux is recovered, then
S4off;att 15;counters -1 4;plotselect pdbs;move_pind2z_out;att 7;shutteroff;
Check flux on pdbs (step 3)
After this, if flux on pdbs is still less than what it should be,
perform "step 6".
S2off;
10. Flux should be fine by now.
Note:
(i) lup is the same as dscan.
(ii) To check counts, look at the top visual display or do "ct" in spec and look for
the specific counter. |