Testing!

test

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.

An MCIS vacuum trip occurred somewhere around 15:30. Sophia observed a drop-off in beam. The cause looks like the PLC-related business that we have experienced many times before. This fault has not manifested itself for quite a while, since Controls firewalled the MCIS portion of the network on March 30th.

As noted, Keerthi was called to restart the source after a power bump. He continued Supernanogan development through the night (can you imagine?!?). He made some great progress. Here is a partial summary of his findings.

Actions taken: frequency scans across the entire range from 12-16GHz for each charge state of 18O.

For 18O4+, the "perfect" resonance occurred at 13.00GHz, with other resonances at 13.26, 13.54, 13.74... i.e. at about 26MHz intervals. The lowest resonance is the least noisy. However, if it trips, it is also impossible to restart it without playing with the RF. Based on Keerthi's instructions, I have written up a draft of an ION note for Operations, describing how to restart the Supernanogan source if it trips. I have asked the operators to critique the draft. The present RF state is attached below.

We have a change of schedule. Due to circumstances, Sophia will continue tuning to TIGRESS this morning. Sgan Development will resume this afternoon.

Details: The beam path through the TIGRESS chamber is clear presently, and no detectors are mounted. It is the perfect time to send a nA pilot beam to the end of the line. TIGRESS intends to install electronics starting at noon. Sophia expects to have tuning comfortably completed by then also. She and I have agreed to the following schedule: 

Note: An SC vacuum issue arose this morning, which truncated Sophia's tuning efforts for today. We have agreed to a slightly earlier handover time on Friday, so that she can tune through the chamber. It will be more difficult, as there will be detectors installed by then.

Beam has been on FC6 for an hour or so. It looks pretty good. Stripchart attached. Save: 090714_1231.snapmcissebt3a. Note: There is something fishy about the slit panels. I think an IOC got rebooted somewhere along the line, and the slit motors are out of calibration. I have recorded the pot values in the save file. Emittance scan of Sopohia's 18O4+ beam appended.

I have begun a mass scan from 0 to 25. It will be a while. Data file: masscorr_mcis__0-25_090714.txt. 25nA of 18O4+ restored to FC6.

Proposed run plan for this time:

• Document TIGRESS tune.
• 18O4+ emittance scan.
• Mass scan A/q = 0 to 25.
• Repeat 18On+ emittance scans at present RF frequency. 
• 16On+ emittance scans at present frequency.
• Plot 16On+ & 18On+ emittance on one graph.
• If indicated, then do 17On+ background study.
• Open 17O gas bottle to system.
• 17On+ resonance survey based on 18On+ results.
• 17On+ emittance scans.
• Add 17On+ emittance values to graph.

Repeat emittance scan of present 18O4+ beam. It compares okay (somewhat broader emittance numbers)  with yesterday's scan. Also attached is FC6 beam overnight. Nice.

A/q = 2.25 Field = 704.7G FC6 = <pA

Well, it's there, but pretty faint. The attached stripchart shows no beam then beam. FC6 bias has to be revered to see it.

A/q = 2.571 Field = 752.9 FC6 = 88pA

A/q = 3 Field = 813.2 FC6 = 2.9nA

Beam is too faint for a good emittance scan, but it's visible. Redo with reverse bias, if possible...

Sideshow: IOSIOC reboot for Maintenance. Recovery protracted... Some MWS bias interlock problem. Also, many optics devices were zeroed. (When will this be fixed anyway?) Fortunately the MCIS optics actually stayed in their prior states.

Later... Request Operations reboot IOSIOC, as interlock condition is still there, and it prevents me from seeing A/q. Nothing to lose. Nothing gained either. Graham is here, and we've been discussing stuff. Recently I got the MWS bias on, with glitches. I can no longer turn it off, but that's fine for me. Let's move forward with emittance now.

After many attempts, here is the first emittance scan. Looks like coarsely ground pepper.

A/q = 3.6 Field = 888.6G FC6 = 10nA

Two emittance scans, one with the as-is emittance rig, one with a manually installed battery for bias.

Graham looked up the list of IOS bias assignments. None was form the emittance rig. I quickly tested the list in ILT, but nothing jumped out. Keerthi provided a battery setup, which I have now installed. Here are example scans, untouched, of forward and reverse bias. I leave it to you, dear reader, to figure out which is which.

18O4+ beam restored for the night. Take a scan and verify it's restored well. Nice.

The MCIS vacuum system tripped last night again. Fortunately the operators noticed it and restarted stuff. Otherwise we'd be having a very long day today. This looks exactly like the same MCIS:PV1 trip we've experienced before. Attached is the FC6 beam recovery.

I ran through a calibration exercise for the IOS slits. Here is my data. I have moved each set to the midpoint of the largest (5mm) slit position. This does not necessarily agree with the book value. Never mind. Leave 'em alone, even though it appears that the numbers are switched (they're not).

Check 18O4+ emittance and compare with yesterday: good. Note again that emittance rig is running with manually-fitted reverse bias.

A/q = 4.5 Field = 993.5G FC6 = 24.0enA

A/q = 2 Field = 662.3G FC6 = 150epA (unstable)

No emittance scan possible.

A/q = 2.25 Field = 702.5G FC6 = not visible

It looks like last night's vacuum trip is biting us here.