The QH trim quads have been measured and are ready for sign off. The DF and DG µ-metal correctors have been assembled and are ready for measurement. The DY, 180º bend magnet, for the 5F region is still being rebuilt.

The optical transport system in upstairs is now cleaned.

Commissioning

This week's activities generally involved running low-average-current beam to the straight-ahead dump and using it to commission the Machine Protection System (MPS), especially auditing the beam-loss monitors (BLMs), as well as various diagnostics including the beam-position monitors and multislit emittance monitor. The multislit needed to be gated at 2 Hz in keeping with the logic of the MPS, and this new feature required debugging. At this writing (1200 Friday, 3 Apr. 98), there is some indication that the electron beam is not properly aligned through the cryounit, and time is scheduled in next week's plans to try to clean up the beam before working toward optimizing injector setup for 60 pC.

Note written at 1640 Friday, 3 Apr. 98: The most exciting shift of the week was Friday's day shift. After completing the BLM audit, we set up the straight-ahead dump for high average current. We then ramped up the current at 18.7 MHz and reached 500 microamps cw, corresponding to almost 30 pC per bunch. We could easily coast stably at 350 microamps cw. We then switched to 9.3 MHz and ramped the current up to 550 microamps cw, corresponding to 60 pC bunches. The machine sat there for a couple of minutes and then the MPS tripped by way of one of the BLMs near the straight-ahead dump. We need to fine-tune the machine settings to clean up the electron orbits at 60 pC before we can go to 1.1 mA cw, but this is a really good start!

We are implementing some sanity-preserving measures. Starting now, we will be running from 0800 Monday through 2400 Friday each week, and we will not run during the weekend. Beginning 6 Apr. 98 we will run from CEBAF's Machine Control Center (MCC) and generally will have CEBAF operator support. Exceptions will occur if there are serious problems with the nuclear-physics machine, or possibly following major nuclear-physics-machine down times. There will undoubtedly be some bugs associated with starting to run from the MCC, but we will work through them.