Keerthi suggested using 16O5+ for optimizing the source. I did a tight mass scan in that area, and 16O5+ is clearly visible. I will use it for some source tweaking. Also, I used Gabe's calibration program to slightly adjust the values of the two constants. There are some 10nA of 16O5+ on FC6 presently. Final settings for today, etc. are attached below.

The 16O5+ beam stayed up OK overnight. ICR took some emittance scans this morning. They look interesting. A finer resolution scan is in progress presently. Goals today:

1. Comprehensive mass scan to A/q=100

2. Characterize 16On+ states, including emittance scans where possible.

Mass scan is in progress now. First look is attached below. The full scan is shown in Gabe's Calibrate application. Note the apparent lack of 84Kr, after a night of pumping with the source gas valve closed. A subsequent scan from A/q=0 to 20 is shown next. The same scan zoomed in at yesterday's scale is also shown for comparison of background intensities, particularly 16O5+ with A/q=3.2, which are higher today due to source tweaking this morning. Now I will start a series of emittance scans, starting with 16O5+ as a benchmark. I expect it to be near-identical with this morning's scan.

A series of 16On+ emittance scans. Benchmark scan of 16O5+ matched well with same scan done this morning. Subsequent scans beginning with 16O1+ were thwarted by an IOSIOC seizure in the emittance rig EPICS panel, and an IOC reboot was required. ICR restored last saved DRAGON tune. So far, so good. Ah, well, not so fast. I have to go fishing for beam on FC6. This may take a while... That's it for today.

As mentioned before, IOSIOC was rebooted yesterday afternoon to unfreeze the emittance rig panel. It cost us our tune, which unfortunately wasn't saved very well. Lesson learned: Save often. I will run a mass scan now and check the mass correlations calibration. Then I will pick up with some 16On+ emittance scans. Keerthi was here until late last night working with the beam also. He will have some results for sure.

The first emittance scan of the day is in, 16O1+ at 10:29.

The second emittance scan of the day is in, 16O2+ at 11:00.

Break for a mass scan to A/q=50. (Fire alarm in ISAC-II rang around 11:30.) Here is the first part. I have run the data in Gabe's Calibrate program and adjusted the two constants slightly. Looks very good. BTW there are some new artefacts in the mass correlation plot that weren't there before. They don't affect anything but the appearance of the plot. However, they do append a few lines of spurious data to the plot data file, which have to be expunged manually.

The third emittance scan: 16O2+ check at 13:08. Looks OK.

The fourth scan : 16O4+ and friends at 13:24.

The fifth scan: 16O5+ at 13:31. This one should be redone.

The sixth scan: 16O3+ at 13:39.

Keerthi developed a nice 16O7+ beam to FC6 last night. Beam current is about 3nA presently. Here is the first emittance scan from 11:05 today. A little spotty, but it's there. Higher resolution scan at 13:58 follows.

The third plot at 16:12 is 16O6+.

The fourth plot at 17:05 is a 16O5+ scan. However, the emittance rig stopped scanning at position #50, and is frozen at position #0 now. The operators are looking into it, and will reboot IOSIOC. I am ready to restore optics. Later... reboot and restore went well. Continue emittance scans.

The fifth plot at 18:36 is a higher res 16O5+ scan.

The sixth plot at 18:52 is 16O4+ and friends.

The seventh plot at 19:12 is 16O3+. It does not compare well with yesterday's scan of the same beam. Note that recovery from yesterday's IOSIOC reboot required a retuning effort. The source RF was changed in the interim also.

The eigth plot at 19:34 is 16O2+ and friends.

The ninth and final (for tionight) plot at 19:53 is 16O1+ and friends.

Here is a list of 16On+ emittance scans for today. Although IOSIOC got rebooted, restored tune was identical and trouble-free, and RF was untouched. Save file: 090619_0859.snapmcisfc6. Emittance values: pi-mm-mrad at 39%, 63%, 86% and 90% respectively. Here we go.

16O1+ datafile profile emittance 6.19 10.8 16.6 17.6

16O2+ datafile profile emittance 2.94 5.51 8.96 9.62

16O3+ datafile profile emittance 2.47 4.57 7.62 8.22

16O4+ datafile profile emittance 1.88 3.62 6.28 6.82

16O5+ datafile profile emittance 1.62 3.13 5.57 6.08

16O6+ datafile profile emittance 1.55 2.99 5.25 5.7

16O7+ datafile profile emittance 0.779 1.42 2.14 2.27

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.

In anticipation of 16O2+ delivery mid-week, we checked 16O2+ production from the Supernanogan source. No problem. We did have to use the tightest slit settings to achieve a low enough current for the user. Here are emittance scans, normal and with our test booster amplifier inline respectively. Subsequently we set up the line to match into the RFQ. Bias is at 16.32KV. Then we returned the mass selection to 16O7+ for the night. A final emittance scan of 16O7+ for today is shown. It clearly needs a stronger signal. With some slight tweaks, there are some 1nA of 16O7+ on FC6 now.

Today is the last day of this set of Supernanogan Development. The source ran at 16KV overnight, in anticipation of 16O2+ delivery later today. I expected more bias sparking, but it appears that it sparked off only once. So I will condition at a higher bias later today. Meanwhile, the operators reported touching up the tune with the magnet and the RF. Perhaps we are seeing some temperature effect on the source, so I will be looking at effects of RF on 16O7+ for the next while.

 Below is a stripchart of the beam (in blue; turquise is RF power) for the last three hours, of which the last 150 minutes are at the present settings. Pretty good, I'd say. I double-checked the range on the RF, and it's exactly the same as the start. Excellent. To round things out, here is a last emittance scan of 16O7+ before we move to 16O2+.

We now have about 80nA of 16O2+, using the same source parameters as before. Keep a watch for a while, then tune the source to match user's needs, somewhere in the 10nA range.

Here is a stripchart of the 16O2+ beam for the last half-hour or so., and also the stripchart of it juxtaposed with 16O7+ earlier. Also a first 16O2+ emittance scan for this run. I will do source tuning with it momentarily.

After a first round of source and line tuning for good current with minimum RF power, we have about 8nA of 16O2+ on FC6. Here is an emittance scan of that. Present RF settings are 15.438GHz and -1.0dB with less than 1W of RF power. Bias is 16.32KV. Let's do some bias conditioning for a bit.

Supernanogan bias for this run is 16.32KV. After we were finished with source tuning, etc., we conditioned up to 20KV. Then beam was returned and 16O2+ tuned saved as 090623_1730.snapmcisfc6. Next step: Prepare MWS for dual operation. Source open now for source gas installation. Then Keerthi will develop a daul-mode tune, where the B1A bender only need be switched on or off to run either the MCIS or MWS source.

See ISAC elog entry today.  Keerthi developed a dual-mode tune last night, so that we can run the MWS at will if so desired. Save file: 090624_0930.snapmcisfc6. Emittance scans done. Overnight FC6 also attached. Sophia took the beam at 10:00.

Note: This is an updated emittance plot. The bias voltage was incorrect in the original datafile, therefore so were the emittance calculations. The plot itself is identical.

We handed over a 16O2+ beam on Wednesday morning to Sophia for TACTIC setup. On our side, everything went well. TACTIC switched to RIB on Saturday night. See ISAC elog entry. We remain on standby for pilot beam. Schedule switched to development tomorrow morning. Attached is a stripchart of our beam for the last several hours. As good as it gets! Save file: 090629_1730.snapmcisfc6.

Supernanogan development starts today. The TACTIC run, which ended around 08:30 today, appears to have been a success. TACTIC used our beam for setup and pilot, then took 8Li from downstairs. Marco is doing some EOB checks now. We will begin at 10:00. First part of our run plan will be to compare the present 16O2+ beam with how it looked when we started, and identify what might have changed.

Proposed Run Plan for Today &ff

1. Compare present 16O2+ beam with start of TACTIC run and identify change factors.
2. RF frequency scans versus each charge state of 16O.
3. Identify frequency with largest bandwidth for each state.
4. Emittance scan for best beam of each state.
5. Compare with earlier emittance scans.
6. Select one clean beam and test whether or not RF amplitude changes best frequency.
7. Comprehensive mass scan.
 

Setup teething pains... The Start button on the emittance panel worked this time. But ICR called, requesting a few minutes more for Marco. No problem. When I went to restart the scan, the button no longer worked. Restarting X11 made no difference. However, there is a significant update available for X11, so I am installing it now. I perceive that it works, yes, significantly faster than its predecessor. Good, all good.

The first emittance scan sort of got interrupted; it auto-restarted just before the previous scan had finished. I thought the resulting plot was somewhat interesting. The emittance isn't half-bad either. A better scan follows. TACTIC took beam again for a while this afternoon to shake down a timing discrepancy. We got it back around 4pm. One more emittance scan for good measure.

First, with upstream slits opened, then with both open. Original slit setting was 1mm. Finally, restore slits to 1mm and see if it reproduces. It does.

There seemed to be some small change to the beam over the week of TACTIC running. I would like to poke around a bit. The emittance plots suggest some vertical movement at least. The two plots are the before (emittance) and after (emittance). The two tune saves are 090624_0930.snapmcisfc6 and 090629_1730.snapmcisfc6 (present tune) respectively. Here is how they look juxtaposed. I restored the downstream elements. Let's see what that looks like in an emittance scan. They compare well! All changes in beam position can be completely attributed to tuning changes. End of story. I have restored the tune and centred up the emittance plots. Done.

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.