After accessing the OLIS cage and opening the 18O source gas valve, I restarted the Supernanogan source last evening around 18:00 ( just to the left of -15h on the attached stripchart), with the line set up for 18O4+. The beam on FC6 grew nicely overnight. MCIS pressure moved from ~6.5e-8 to ~7.1e-8 Torr since the 18O source gas bottle was opened last evening.

Starting frequency: 15.7864GHz => 870pA on FC6  Step size: 1MHz. Selected peaks shown. There were many smaller resonances in-between also.

Strong peaks at:

15.8594GHz => 7.5nA

15.9834GHz => 1.3nA

16.0354GHz => 1.3nA

16.107GHz => 1.5nA

16.183GHz => 0.9nA

16.247GHz => 1.4nA

16.284GHz => plasma extinguished

16.248GHz => plasma re-ignited

15.860GHz => 7.5nA

15.685GHz => 3.5nA

15.518GHz => 2.5nA

15.486GHz =>  27.5nA

15.479GHz => 4.3nA

15.277GHz => 2.8nA

15.130GHz => 3.7nA

15.035GHz => 6.2nA

14.903GHz => 3.8nA

14.799GHz => 2.6nA

14.763GHz => 11.8nA

14.554GHz => 8.8nA

14.455GHz => 4.2nA

13.588GHz => 1.1nA

13.398GHz => 3.0nA

13.281GHz => 2.7nA

13.223GHz => 7mA (unstable)

13.153GHz => 7.5nA (unstable)

13.061GHz => 10.0nA (unstable)

13.019GHz => 40.0nA

13.002GHz => 50.0nA (unstable)

12.986GHz => plasma extinguished

13.089GHz => plasma re-ignited

15.4798GHz => 30.0nA 

Tune saved as 090708_1200.snapmcisfc6. I settled on the 15.486GHz optimal frequency, and tweaked that for effect. Then I ran a few emittance scans. During that process, I noticed that the beam intensity had stepped down and up a few times. So I tweaked the frequency again to return 30enA on FC6. Note that in this process the beam shifted slightly in the horizontal plane. The emittance shape is different also. Attached are emittance scans in sequence, the last one being the "real" one for this test. Finally, before and after RF screens.

15.480GHz => 30.0nA

P.S. Appended is a stripchart of the 18O4+ beam on FC6 following the emittance scans (magenta trace, between T-5 and T-4h). Not bad, eh?

* 18On+ emittance scans at present ion source settings: complete today.

* 18On+ frequency measurements: Thursday.

* 17O source gas: open end of Thursday.

* 17On+ frequency survey: Friday.

* 17On+ emittance scans at idealized source settings: Monday.

* Development completion: Tuesday.

* 18O4+ setup for beam schedule: Wednesday.

A mass scan from A/q of zero to 25 is in progress. Data file (large): masscorr_mcis_090708.txt. The source is optimized for 18O4+. Fishing for 18On+ states and their emittance scans to follow. Attached is one screenshot of the Gabe's Calibrate interface. I ran it several times with different peak selections from the same data. I entered into the EPICS mass correlation program a best average of the calibrations for the two constants.

First up is a check scan of 18O4+. There is a definite vertical offset compared to earlier today. Otherwise, it correlates well enough. The same beam taken with a greater vertical offset follows, together with the modified emittance panel.

Here we go. A/q = 18 FC6 = 141.0nA MB = 2078G @ 130.2A

A/q = 9 FC6 = 50.0nA MB = 1470.8G @ 90.8A

A/q = 6 FC6 = 49.5nA MB = 1201.4G @ 73.1A

A/q = 4.5 FC6 = 29.5nA MB = 1041.8G @ 62.4A

A/q = 3.6 FC6 = 12.5nA MB = 931.8G @ 55.3A

A/q = 3 FC6 = 5.5nA MB = 851.5G @ 50.1A

A/q = 2.57 FC6 = 0.25nA MB = 790.0G @ 46.2A

Not enough intensity for an emittance scan.

A/q = 2.25 FC6 at reverse bias MB = 736.9G @ 42.9A

Not enough intensity for an emittance scan. Possibly on the edge of A/q=2.3 (23Na10+?).

The 18O source gas bottle is online. The ion source was optimized for 18O4+ and kept the same throughout. Emittance scans of each charge state of 18O were attempted. Visible scans were found for all states up to 6+. At least one more set of scans is desireable. Present beam is 18O4+. Next up: RF frequency survey with 18On+.

Keerthi did some 18On+ frequency scans this morning. He observed 18O8+! I am attempting to repeat it myself now. Reverse bias on FC6.

Peaks at:

13.0277GHz => 1epA (unstable)

13.1023GHz => 1epA (unstable)

13.1695GHz => 10epA (unstable)

13.1672GHz => 20epA (unstable) stripchart attached

13.006GHz => .7epA stripchart at 17:24 attached

First, optimize current versus frequency and amplitude. Unfortunately at 5dB the beam blinked out. Go fishing, then find it again. Attached is stripchart at 17:30, where I was optimizing, then switched bias to Normal, then watched beam blink out. Then stripchart at 17:49 shows beam back again, reverse bias on the left and normal bias on the right: ~10epA. RF settings also attached. Minutes later, beam is still on. FTR, the original RF is appended at the end.

Here is a striptool of 18O8+ beam (magenta trace) last evening from about 18:00 to 22:30 when there was a large power bump coincident with a plane crash in Richmond last night. Before the trip, beam current was about 20epA on FC6 (normal bias).

The Supernanogan was restarted this morning, after last night's power bump. 18O4+ on FC6, cooking for about an hour. Looks very good. Keerthi is doing frequency scans today to find best resonances. Time permitting, he will do this over a range of 18O charge states. At some point over the weekend (my guess is tomorrow evening), he will open the 17O source gas bottle to the system.

The Supernanogan was restarted this morning, after last night's power bump. 18O4+ on FC6, cooking for about an hour. Looks very good. Keerthi is doing frequency scans today to find best resonances. Time permitting, he will do this over a range of 18O charge states. He is also developing a dual-mode (MCIS/MWS) IOS tune. At some point over the weekend (my guess is tomorrow evening), he will open the 17O source gas bottle to the system.

As per our agreed deal last week, today is reserved for Supernanogan tuning to TIGRESS. Development will resume tomorrow.

There was a power bump overnight that knocked out many systems, including OLIS. The ISAC elog mentions something about it here. It seems that Keerthi restarted the source. (Note to self: Write an ION with brief restart instructions for the Supernanogan.) 18O4+ beam was left on FC6, and it is very nice, as you can see. Sophia has the beam now.