Revision as of 19:02, 16 December 2021

Friday December 17

Last 24h:
- Smooth production on LD₂ at 140 nA, 0/90 para and perp. Took one amorphous run (90578).
Issues
Plans
- Continue running on LD₂ at 140 nA, 0/90 para and perp until 1:45pm (if empty target run is needed) or 3:45pm (if not).
- Target change LD₂ → L⁴He:
  - If an empty target run is desirable, start emptying the target and turn off pulse refrigerator at 1:45pm (assuming a 2h run). Otherwise, start emptying/pulse refr. off at 3:45pm.
  - 2pm-4pm: 2h empty target run?
  - 4pm. Ask MCC for beam off and Rapid Access. Chris Carlin goes in the Hall to start switching gas. Solenoid will stay on: be aware of magnetic field fringes.
  - Between 5pm and 6pm: Chris is done switching gas. End of rapid access.
  - Ask for beam. (No need for beam restoration check as the beam down time is small): while the target cools down (about 3h process). A. Somov will take test data.
- around 9pm: target is cold. Start running on L⁴He at 150 nA, 0/90 para and perp.

Last 24h:
- Smooth production on LD₂ at 140 nA, 0/90 para and perp. Interrupted only by search for better spot on diamond (~1h see below) and ~1h of RF-related down time.
- Spectra from A. Somov.
Issues
- JD70-105 degradation: Hovanes tried to find a new location that improved the 0/90 para and 45/135 para/perp coherent peaks, but to no avail.
- Target lost the Labview readout twice last night (2:20am and 5:50am). Chris Carlin came the first time and fixed it. The second time, we fixed it following his instruction and it worked.
- Rates are ~10% lower compared to previous LD₂ data taking period, see here. Part of it is lower transmission but even accounting for this, normalized rates remains 6% lower (see trigger/PS, black disk symbols, here). The comparison between the time-evolution of the Trigger/PS rates for diamond and amorphous radiators shows that the (non-transmission) drop is due to the diamond deterioration rather than detector deterioration.
Plans
- Continue running on LD₂ at 140 nA, 0/90 para and perp. Do one amorphous run today.
- Discussion on possible target change to L⁴He.
- Status of possible CPP test.

@@ Line 8: / Line 8: @@
 #* Continue running on LD<sub>2</sub> at 140 nA, 0/90 para and perp until 1:45pm (if empty target run is needed) or 3:45pm (if not).
 #* Target change LD<sub>2</sub> → L<sup>4</sup>He:
-#** If an empty target run is desirable, start empty the target and turn off pulse refrigerator at 1:45pm (assuming a 2h run). Otherwise, start empty/pulse refr. off at 3:45.
+#** If an empty target run is desirable, start emptying the target and turn off pulse refrigerator at 1:45pm (assuming a 2h run). Otherwise, start emptying/pulse refr. off at 3:45pm.
 #** 2pm-4pm: 2h empty target run?
-#** 4pm. Chris Carlin goes in the Hall to start switching gas. Rapid access. Solenoid is on (be aware of magnetic field fringes).
+#** 4pm. Ask MCC for beam off and Rapid Access. Chris Carlin goes in the Hall to start switching gas. <font color="red">'''Solenoid will stay on: be aware of magnetic field fringes'''</font>.
 #** Between 5pm and 6pm: Chris is done switching gas. End of rapid access.
-#** Ask for beam. (No need for beam restoration check as the beam down time is small): while the target cools down. A. Somov will take test data.
+#** Ask for beam. (No need for beam restoration check as the beam down time is small): while the target cools down (about 3h process). A. Somov will take test data.
 #* around 9pm: target is cold. Start running on L<sup>4</sup>He at 150 nA, 0/90 para and perp.