Happy Canada Day!
I noticed a long-term trend in beam intensity. I have every reason to believe that the source itself is rock-solid. I think it is temperature variation affecting the Philtek power suply on the separator magnet. What bothers me is that the stability program appears to not be compensating for this. I am looking into this now. Here is a plot of beam current, mag field and temperature (at AHU-1, the best I could do). There appears to be a delayed response to temperature. I have turned off our Hall probe for an hour or so to watch the response on a stripchart.
Well, there were results, but not what I expected. The beam became nearly out of control while the stability program was disabled. What's more is that the correct field came back immediately upon turning on our Hall probe again. Here are a couple of stripcharts, one snapped right after turning on the probe, and again a while later The stability program was disabled during the middle couple of hours or so. Note that the beam is oddly more stable in the short term now also. |