COMMENT ON Measure Voltages of Laser Intensity Attenuator System in CEBAF
Checked the front, and inside, of the existing IA driver:
Checked the front, and inside, of the existing IA driver:
Measured the Hall C IA output on the oscilloscope, and exercised the Hall A & B outputs. Found crosstalk between the halls due to the power supplies for the outputs being underrated:
With RTP OFF, the asymmetries obtained from the batteries are consistent with zero:
https://logbooks.jlab.org/entry/4472811
The JLab RTP drivers have been renamed "JLAB-RTP-HV-1.1" and "JLAB-RTP-HV-1.2". With this "X.Y" naming nomenclature, X denotes the revision, and Y is the serializing number. E.g. "1.2" indicates first revision, second box. The spare box we will build will be "1.3" and so on.
As Kitty noted in the linked log, the discriminator wanders quite a bit then takes time to come back in, Cavity 2 is quench limited around 16.5 MV/m.
We tried quench masking to push the gradient a little further but it did not help. Still quenches around 16.5.
The OPS DRVHs for the following cavities have been updated:
2L11-2
Username: bschauml
Date/Time: 02-24-26_23:43:36
RF Status: Good
Tuner Status: Good
Comment: DRVH=6.600 Waveguide Window Temperature Fault
Previous OPS DRVH: 0
Special Instructions:
Finished +/- 2kHz loop for cavity 7 then moved to gradient and FE measurement
For cavity 7: reached 22.4 MV/m before cavity quenched. No FE up to this gradient. Completed a one hour run at 21.9 MV/m
For cavity 5: Reached 21.6 MV/m. With a lower loaded Q (1.6E7), we're measuring 6 - 7 kW of Fwd Pwr. Seeing many waveguide vac and arc faults. May just call Emax at 21.6 MV/m.
Some mild FE above 20.5 MV/m ~ 400 mR/hr