Conveniently scheduled for BC Day, we are preparing to switch over the MWS to sputter operation with MG source material. Operations has saved present 21Ne tune.

Later... Done! Source is relit with 21Ne beam on FC6.

Summary:

• Vent IOS to Ar
• Remove MWS backplate
• Machine Mg metal disk (source material) for mounting screws
• Hand-cut Mg disk in two halves and clean
• Clean backplate
• Attach disk halves to backplate
• Clean assembly
• Reassemble at OLIS
• Pump - roughout was fast
• Pump - turbos on
• Minor MRO
• Button up and go with previous settings.

We will let it run this way overnight and shoot for an Mg plasma and beam tomorrow.

Attached below are plots of the last few hours of 21Ne beam. PDG, I'd say. Note the variation in sync with room temperature.

21Ne has been available from the MWS since mid-week. Here is roughly how last week unfolded to now:

Monday: MCIS -> MWS and remove MCIS cart
Tuesday: leakcheck MWS source gas manifold
Wednesday: Controls fixed interlock oddity on IOS:BIAS
Wednesday: Begin setup for TUDA-II
Thursday: continue tuning to TUDA-II
Thursday: prepare to commission new SEBT NIM
Friday: commissioning of new SEBT NIM
Friday night: begin setup of beam to TUDA-II
Saturday: 21Ne5+ delivery to TUDA-II began at about 07:30 for the first time
Saturday: 21Na5+ delivery to TUDA-II switch at about
Saturday evening: power bumps knocked out OLIS and other systems - thunderstorms - go idle for the night
Sunday afternoon: check tune with pilot beam
Sunday night: resume RIB delivery

I expect several energy changes over the next little while.

At the Beam Delivery meeting today, we discussed the up-coming 25Mg run, which has scheduled a mere 48h of turnaround time. I made it known that there is *no* margin in that time allocation. I put in a bid for the preceding Friday, August 1st. Marco didn't think it would be available that soon.

Last night Keerthi resolved the sparking issue in MWS and started the source while I was present. There was a frozen interlock condition ion IOS:BIAS, which Graham resolved today. HV was on by ~11:00. Beam on FC6 immediately. It looks like Sophia took the beam at that point. I noticed that the Kepco appears not regulating, and in any event is close to a limit (0.3A). I have asked Sophia for five minutes to reset it.

It turns out that the system cannot see the Kepco on the USB port. This has occurred before. It will take some investigation... later. Also, the gaussmeter is reading erroneously, and MagStab iappears to have picked up the EPICS probe values instead, although no field corrections are being made.

Vacuum came down to ~7e-7 Torr. On startup, bias sparked over somewhere. Vacuum leak was caused. Later we found that HV had sparked through the source gas tubing, which was touching the beamline frame. Obviously an arc had formed within the tube and sparked through on the ground side. We also could not reset the bias interlock (ICR has efaulted this), so we ran in local. System is set up for 21Ne with about 28nA on FC6. Bias is off for the night, while plasma remains on. Bias can be turned on at will, preferably via EPICS. Fine-tuning will take place mid-morning Wednesday.

Other notes: Neon gas line checked for any sparkover leaks. None. It was closed down and pumped during the course of leak-checking today. Checked: bottle valve open, and line valve open. Plasma electrode in this mode is best near zero. About 3V is good, which locks in one plasma mode. At zero and with the quartz  liner "can" installed, the plasma could toggle through different modes as plasma wanders back and forth through the plasma chamber. Also, microwave power can walk the plasma. Goal: Move the plasma back as far as possible so that a clean beam exits the source, i.e. good beam on cups with relatively small spills on collimators. In an otherwise identical setup but without a liner, the plasma would form adjacent to the backplate, a different mode of operation altogether.

With the MCIS cart removed, Geoff hooked up the leak detector to the MWS source gas line. He did a couple of hours of leak checking in this mode. Then he moved the connection to an empty gas port on the manifold itself. Much qicker responses. We replaced a VCR seal on the bottle side of the right-hand He solenoid valve. That did wonders. He checked around afterwards, but found no further leak. We tidied up and opened the manifold to IOS. Base pressure was about 1e-6 Torr and holding. After an hour or more, I decided to reinstall the leak detector on the manifold to assist pumping. I suspect air trapped on the front-side of the flow controllers. Opening them wide caused a vacuum spike, which recovered. It all seems to be working, and that is where we are right now.

We discussed whether or not to leave the Supernanogan in the OLIS Faraday cage, and decided no, because the up-coming runs will use the MWS at 42 and 52kV respectively, higher than the MCIS HV rating. Bonus: We have more working room in the cage. The cart is out and parked. Services are connected and up.

Run Plan:

• Remove MCIS cart.
• Set up for leak-checking MWS gas manifold.
• Pump manifold through IOS volume.
• Repair leaks as necessary.
• Pump.
• Start MWS with 21Ne beam.

 Beam to scheduled user at 08:30 Friday. TUDA-II safety commissioning is planned for Thursday. Sophia will need beam prior in order to set up into SEBT.

The 18O4+ run at about 5MeV/u ended this morning with reasonable success, I'm informed, despite MCIS vacuum trips, SC cryo trips and a power bump for good measure.This morning I found beam at FC6 unstable. It appeared to be toggling between plasma states. A little tweak of a few MHz up in microwave frequency not only stabilized it but also multiplied the brightness. Too bad the users didn't have this beam. Emittance scan in progress now.

Next up: 21Ne to TUDA-II. We will begin preparations for switchover to MWS operation shortly. We are discussing a run plan now.

Check beam at FC6. Still toggling. Tweak RF from 15.4790GHz to 15.4823GHz, a change of a mere 3.3MHz, and amplitude from 8.470 to 8.670dB. The RF multiplied the intensity, and the amplitude locked the plasma mode. Sweet! Striptools and final RF settings attached. Too bad we have to shut it down now. Close isolation valves, MCIS optics off, vacuum off. Prepare to access cage. Note: Bias and EL could not be turned off via EPICS.

Beam switched back to 18O4+ by 11:00 as agreed. Some glitches. Here are snapshots of how it looked at handover time.

Later... Sophia prefers using all previously-saved files including ion source. Okay.

Note: For fun, Controls took away isacwserv mid-morning. The ICR did not communicate to them that I was the user... Workaround done with Keiko.

A/q = 2.666 Field = 767.1G FC6 = 3enA

A/q = 2 Field = 667.3 FC6 = ~10enA

A/q = 2.2857 Field = 710.5G FC6 = 100pA

A/q = 2.571 Field = 753.5 FC6 = 50epA

A/q = 3 Field = 813.9G FC6 = 2.2enA

I tweaked the adjustment of the displayed A/q calibration to fit this one.

Go fishing in the range 2.24-2.26, but no fish in this pond this time. However, there is a relatively strong beam at 2.3.

A/q = 2.3 Field = 711.2 FC6 = 110enA

No emittance scan possible.

I did a check at A/q = 2, and found a strong peak at 2.04 field 668.8 18enA, suggesting that the A/q panel calibration is slightly off for the lower masses, and in the right direction for the above to indeed be 18O8+. Good stuff.

Next stop: 18O6+.

There are the last couple of hours of Supernanogan Development for this set. Our run plan included 17On+ studies. Time will not permit it this time around. Also, the emittance numbers of 16O and 18O are not distinctive enough as they stand to warrant studies of the in-between mass. Keerthi will run the emittance data files through his software during post-analysis, and we'll develop our next run plan based on his conclusions.

This morning I will redo a couple of emittance scans that were not optimal yesterday. We'll start with an 18O4+ emittance check, then 18O8+, where, though I don't expect an emittance scan, I do expect to see beam. A vacuum trip on Wednesday evening probably compromised source vacuum and therefore the ability to generate the higher charge states. Here we go.

18O4+ emittance checks well.

Here is a summary of emittances gleaned from the aforementioned elog entries.

 18O4+ restored onto FC6 ~20enA, which seems slightly low.

A/q = 18 Field = 1987.1 FC6 = 161nA

A/q = 16 Field = 1873.4G FC6 = 204enA

A/q = 9 Field = 1405.0G FC6 = 55enA

A/q = 8 Field = 1324.8G FC6 = 172enA