An emittance scan of the 16O7+ beam follows. Also, a stripchart of the same beam on FC6 overnight. Keerthi did some studies over the weekend. He found that the characteristics of the amplifiers behind FC6 and the emittance rig cup differ significantly. That's disconcerting. We did a visual this morning, and confirmed that the amplifiers are identical VME modules in the same crate. He believes it's a scaling thing. We will test again with a current source this afternoon.

Later... The apparent discrepancy between the two amplifiers was in fact a bad patch cable in the test setup. So that's solved. The two amplifiers differ in this way, that FC6 has the updated version with the middle gain ranges and auto-ranging, whereas the emittance cup does not. We will be asking Controls to update this amplifier to the now-ISAC standard. The test setup consisted mainly of a very high gain amplifier. Overall, the tests worked out pretty well, as you will see below in an emittance scan of 16O7+ done with the amplifier in the loop. The second emittance scan is 16O7+ and the highest EPICS gain setting, i.e. 1mA.  Note that Matlab is unable to calculate an emittance here. The third emittance scan is the same beam at the next gain setting, i.e. 1uA. We just about make it, with only a relative handful of data points clipped, and Matlab calculates emittance easily.