Latest revision as of 11:55, 21 December 2021

Tuesday December 21

1. Last 24h:
   • ~6h of production on ⁴He (150 nA, 0/90 perp only: para was too degraded.)
   • 3h35 (3:40am-7:15am) empty target data taking.
   • trigger tests in raw data mode and CPP trigger test.
2. Issues
   • Target OVC vacuum.
   • Target temperature increases
   • Transmission rate decreased by 5%
3. Summaries
   • Electron beam energy during the SRC-CT run.
   • Normalized rates for SCR-CT Fall 2021 run
4. Plans
   • End of Fall 2021 run. Hall shut down tasks:
     • Secure beam line:
       • All radiators retracted.
       • Collimator in blocking position.
       • PS and sweeping magnets off.
     • Solenoid ramp down.
     • Target will already be empty. Keep PTR on since the target group might do some investigation of the vacuum event.
     • High and low Voltages off.
     • Crates will be kept on.

Monday December 20

1. Last 24h:
   • ~4h of production on ⁴He (150 nA, 0/90 para and perp).
   • 2 long down times: ~5h between Sunday 9am-13:45 (multiple causes. Mains ones: Bulk power supply and 1L04 RF). Monday: 1am-ongoing (IL05 RF).
   • 2h on Amorphous radiator (runs 90631, 90632).
   • CPP trigger tests (~5h)
2. Issues
   • Target pressure event due to large vacuum spike in the Outer Vacuum Can (OVC). No incidence on data taking. (Most of the event unfolded during beam down time in any case.)
   • Target status and comments from Chris C. and Hovanes
   • Target status (7pm)
   • Diamond degradation
3. Plans
   • Production on ⁴He (150 nA, 0/90 para and perp) until Tuesday 7am.
   • 3h trigger tests in raw data mode.
   • 1h CPP trigger test.
   • Finish run period with ~3h Empty target run, from 3:30am (12/21/2021) to shutdown around 7am. (This will permit to check if the target event above has made ice to accumulate on the target cell).
   • No analysis meeting today

Sunday December 19

1. Last 24h:
   • Smooth data collection on ⁴He (150 nA, 0/90 para and perp).
2. Issues
   • Nothing special.
3. Plans
   • Production on ⁴He (150 nA, 0/90 para and perp).
   • Amorphous run Sunday morning.
   • CPP trigger tests (During A. Somov shift in the afternoon.)

Saturday December 18

1. Last 24h:
   • Collected data on LD₂ at 140 nA, 0/90 para and perp until 14:10. Then started empty target run, as planned before switching to ⁴He.
   • 1h empty target run (run 90602, Diamond 0/90, para, 150 nA).
   • Access for target gas change (C. Carlin).
     • Sasha and Vlad took advantage of the access to re-position the calorimeter prototype.
     • During the ⁴He cool down, Sasha used the beam for PS background test (0/90 PARA)
   • Around 23:00 (Friday) ⁴He reached nominal temperature. ⇒ Ready for production but the beam was unavailable. About 1:50am: Started production on ⁴He (150 nA, 0/90 para and perp).
2. Issues
   • Target's boiler heater malfunctioned. Access was necessary (C. Carlin). It reduced to empty target run from 2h to 1h.
   • Rootspy failing to connect. Issue solved by Alex. A.
3. Plans
   • Production on ⁴He (150 nA, 0/90 para and perp).

Friday December 17

1. Last 24h:
   • Smooth production on LD₂ at 140 nA, 0/90 para and perp. 3 beam interruptions (1h+0.3h+2.5h). Took one amorphous run (90578).
2. Issues
   • Target's Labview monitoring hanging: C. Carlin rebooted target control computer. Caused a 2.5K drop in temperature (happened during run 90579). No Labview problem since then.
   • Target LD2 nominal temperature before reboot was 1.3K higher than nominal temperature after reboot.
   • Current lock. Consequence of 2.5h accelerator down due to PSS fault. Fixed
   • Diamond degradation.
   • On Shift: Current Issues page
3. 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 → ⁴He:
     • 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.

Thursday December 16

1. 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.
2. 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.
3. 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.