[Halld] Commissioning update

[Alexandre Deur]

Dear Collaborators,

The accelerator is successfully delivering beam to Hall A and D since yesterday afternoon. An important milestone reached for the accelerator group. We started receiving good CW beam yesterday at about 4pm. Since then we have done several steps in our runplan, https://hdops.jlab.org/wiki/index.php/Post-thanksgiving_period#Post-thanksgiving_period. You can follow the progresses on the runplan: I am updating it to reflect our advances. To summarize them:

*Accelerator re-established a good photon beam with good radiation levels in both the tagger hall and Hall D. Radiation studies at different radiator thickness were done.

*Alex Barnes re-performed a calibration of the Active Collimator. This was necessary to verify the stability of the calibration and because the vertical calibration had not been completely done.

*Alex Somov measured the background level in the pair spectrometer. Thanks to the newly installed secondary collimator, the background is now reduced by a factor of 20 compared to the running done before Thanksgiving.

*Alex Somov successfully tested the TOF cluster finding Level-1 trigger algorithm.

*4h hours of regular data (FCal trigger) were taken in order to continue detector checkout and gather more statistics for checking PID.

Next steps today is to optimize the DAQ, work more on trigger optimization and check new triggers, and BCal data taking with the BCal trigger.

Best regards,
    
Alexandre Deur, Hall D Run Coordinator.
        
RC cell: 757-383-5542
Office Phone: 757-269-7526