I checked the PMC mode matching by ramping the gain down to -10 dB (from +20 dB) and
moving the DC offset around until it caught lock on the different HOMs. Then I recorded
the output power (PMCTRANSPD). The DC offset on this EPICS channel was -0.013 V, so I
used its AOFF field to zero this out. Here is a list of the power in the largest modes:
Mode Power (V)
---- ---------
00 2.7
10 0.2
04 0.04
02 0.02
BE 0.36 **Bull's Eye mode is TEM02 + TEM20. This can be fixed by lens adjustment.
N.B. To make a PNG file with DTT, just make an EPS file -- then use the eps2png perl script. |