Source stayed up quietly overnight. Current dropped off gradually. I will tweak things shortly.

Beam tweaked up to 3eµA. Pressure is ~5e-7 Torr. Plan for today will include a rework of the arc and plasma power supply wiring to achieve higher V on arc and opposite polarity on plasma.

Later... First iteration of plasma polarity swap was a bust. The supply couldn't handle the back EMF or something, and the beam was unstable. Keerthi tweaked something... Now it's stable. Some measurements taken with varying the arc supply and tweaking the rest to follow. More of the same to come. Meanwhle, there are 6.5eµA of 4He2+ on FC6 presently.

Today we swapped power supplies between the arc and plasma electrode. This gives us a higher voltage range on the arc, at the possible expense of current limiting. We plan an extended round of development in this mode.

Development over the weekend. Results to come. Restart source now and let it warm up. 4He2+ on FC6. Plasma at zero, to duplicate weekend settings. Arc at 150V. FC6 ~=150enA and settling down presently, IG1 = 2e-7 Torr.

Later ~10:00: FC6 ~500enA. Mass scans next.

Later ~14:00: Some scans done. Outcomes to come. Meanwhile, Marco Lovera has manufactured a new aperture for the CUSP source frontplate. It has a larger diameter, therefore should allow a brighter, if more diffuse, beam out of the source. Preparations for venting and installation are in progress now.

Four larger apertures were installed yesterday. This morning we fired up the modified source. It lit immediately. Plenty of beam. Development at 28kV, then scaled to 15kV. Beam intensities and ratios did not scale. Thesis: Space charge effects are too much for 15kV. Also, I3 accel-decel lens p/s needs work. We added a ballast to it today; p/s in tomorrow, then retest.

Today we vary source gas pressure.

Later... Several iterations of pressure, tuning and standing on our heads. Representative emittance scans attached below. TBC tomorrow.

Yesterday: Busy! Source filment changed last night. Source pumped overnight. First start this morning.

Today: Busy! Nutshell: A/q=2 passed to Marco for isotope verification at MEBT.

Later ~16:00 Beam on MEBT:FC5, an historic first for achieving A/q = 2 through RFQ. 1.6enA of (likely) 4He2+. Tuning to FC7 continues.

Later ~16:50: Blips on FC7. Real? Stay tuned.

First emittance scan at 4kV taken and attached. It's rough but indicative.

Keerthi and Marco achieved visible 4He2+ through the RFQ on Friday (or so). Mass spec attached. Development continues today.

Update: First visible A/q=2 beam through the RFQ at about 14:00 on Friday, December 18th, seen on M:5, an historic milestone for ISAC. Beam later observed on MEBT spectrometer around 16:00.

So... lots has happened.

* Supernanogan *

Heater components installed in plasma chamber. Cart reinstalled into Faraday cage. Scroll pump rebuilt! (Thanks, Dan and Edi!) Pumping started this morning.

* Microwave Source *

Wiring restored. Microwave backplate and components restored. Pumping started yesterday and at high vac now ~2e-7 Torr. We will make final inspections and tweaks, then prepare to start.

Later... Source started and first beam observed at ~15:00. Note: Since microwave generator has not been run for a number of months, we did a "soft start", warming up at a few watts at a time for several minutes at a time before going for the gusto. Emittance scans in progress. Done. Beam is a bit off-axis, but it's there. Let it cook for the night. Striptool running.

The MWS stayed up flawlessly overnight. Beam grew from about 2µA to over 5µA this morning. Was it the pre-conditioning of the RF generator? We will look at the beam for a bit now, then shut it down for Christmas.

Welcome to 2010. Shutdown is underway across the site, while beam development is going on at OLIS.

OLIS was shut down over Christmas. We did a "soft start" of the MWS last Tuesday, after refurbishing and installation before Christmas. Worked like a jet.

Today: 4He2+ beam development + emittance scans. Here is the best so far.

FTR: Emittance scan is reverse-biased from external battery.

We will be delivering a 28keV beam to the tuning boys tomorrow for further diagnosis of the 8pi line. In anticipation, I restarted the MWS with 20Ne1+ beam. With slits out, there are around 2uA on FC6. Emittance scan of current tune below.

Same tune again with slits in a 1mm, emittance scan attached.

Gas flow presently at 0.5ccm. I will lower it slightly, as IOS pressure is a little high.

Save: 100113_1830.snapiosfc6

Beam is on for 8pi diagnosis by special request.

We set up beam in IOS yesterday. However, beam blinked out last evening, likely due to insufficient source gas pressure. Source restarted with just a little difficulty this morning. ICR adjusted downstream IOS optics to match into next section. Looking good, and they are tuning now, ~10:00 a.m.

Later... Save: 100114_1103.snapios8pi

Later... they found a problem with 8pi optics, a broken cable somewhere. They will resume testing with beam, once this is fixed.

Emittance scan of beam as delivered with ~1/2 uA of 20Ne1+ at FC6 with slits in at 1mm:

Later... They're done. ICR also tuned the line a little. Save: 100114_1533.snapios8pi

A stripchart of beam performance since we started this morning plus EOB emittance scans to follow.

Voltage              Current             MCIC:IG1

0                            0                       7.35e-8

0.3                        0.2                          "

1.6                        0.4                    9.1 e-8

1.6                        0.4                    7.79e-8 (5min later)

3.3                        0.6                    8.61e-8

3.3                        0.6                    8.98e-8 (5min later)

3.3                        0.6                    9.42e-8(10min later)   14.:36

3.3                        0.58                  7.89e-8                15:28pm

5.8(9.62RB)       0.8(0.48RB)     1.51e-7                 15:30pm

5.8 (9.62RB       0.78(0.47RB)   8.17e-8                 16:30pm

8.5V(14.15RB)  1.0(0.60RB)     9.5e-8)                  16.33pm

8.5V(14.15RB)   0.97)0.58RB)  8.52e-8                  16:45pm

11.6V(19.47RB) 1.20(0.72RB) 1.08e-7                  16:47pm

 15.2V(25.27RB) 1.4(0.83RB)  1.34e-7                   16:53

20.0V(33.02RB)  1.6A(0.96RB) 1.6e-7                    17:00

18.4V(30.52RB)  1.64A(0.98RB) 8.6e-8                  17:30

21.6V(35.92VRB) 1.8A(1.07RB)  9.42e-8                17:40

25.7V(42.73RB)   2.0A(1.21RB)   1.43e-7                17:50

23.6V(23.14RB)   2.02A(1.21RB) 7.7e-8                  20:20

Oven is off                                         7.62e-8              20:22

We ran 32S5+ overnight. Keerthi has been working with the new surface source oven for the last couple of weeks. His results to come. Meanwhile, here are a stripchart of overnight beam plus a few panels after my tweaking. Slits are at 5mm position.

Observations:

• The heater responds smoothly in 0.1A steps.
• There is an optimal heater setting; more is not necesaarily more.
• As always, there are several RF resonances within a range.
• Higher resonance produces more beam but less stable.
• Lower resonance produces less beam but more stable.
• Optimal heater loading technique and current setting will require further study.

Save: 100202_1000.snapiosfc6

Last stripchart is FC6 starting a couple of minutes before shutting off the heater.

Power down everything around 17:30, and turn off IOS turbos. I have left IOS:IV0 open to ensure the intermediate section gets vented before the cart is removed. I am leaving the MCIS turbos on for now,. to continue pumpimg residual sulphur.

We prepared stuff last night. This morning we vented IOS to argon, then swiped. Clean. Lu and Ajit craned out DB3 for us. Nice job, as usual. We will remove it and its neighbors to the ISIS Lab for refurbishing. OLIS Shutdown is scheduled to go until March 10th.

OLIS Shutdown has been in progress for a week. IOS is vented, was swiped clean and opened. DB3 was craned out, a precision job. Note to whover reinstalls this box: Request Lu Sun to do it. He knows exactly how to tension the ropes so that the seals are not at risk of damage. Upstream optics in DB1 were also removed in the standard three sections. No problem removing them. Photos and commentary to follow. Bellows downstream and ahead of separator were removed, and separator box liners were removed. They had shifted since being installed, probably during pumpdown. The level of beam implantation was minimal, so the consensus is to leave them out altogether. This was a test running period for them anyway. Straight-through end flange was removed for this job, then restored again. Likely it will come off later for alignment checks. Inspection of the Y-box optics from DB1 viewpoint shows them to be in pretty good condition. Slight discoloration observed on downstream insulators, but all elements hold HV very well, so we will leave them alone.

Rough short-term schedule: Pull Sgan cart and move to its dock. Work on source gas panel. Refurbish IOS:DB1/3 optics over the next week. Then refurbish the MWS and restore its original source body and 2mm apertures.

Supernanogan cart removed from Faraday cage to dock today. Some beam safety tests on FC6 in progress presently. FC3 was already removed for replacement.

Optics Photos: Lots taken; selected ones here as time permits.

3-Way Switch (DSCN7285.jpg & DSCN7286.jpg) looks pretty good. There is some discoloration on a downstream insulator, but far from worrisome. The elements hold HV just fine.

Q1 (DSCN7312.jpg& DSCN7316.jpg) looks good too. Insulators survived well. Note the interesting halo pattern on the backside of the downstream skimmer plate.

Q2 (DSCN7317.jpg) is in good condition with some plating on insulators.

Q3 (DSCN7330.jpg & DSCN7350.jpg) is complex. Some marked plating has occurred on a few of the insulators from the backside. There is an interesting deposit of metallic material, probably magnesium, on the backside of the downstream skimmer, right behind the quads. A similar depositing is also visible in last year's Shutdown photos. The water-cooled collimator in front of the quads has significant beam etching, which could have been present some time ago (cf. a year ago, DSCN6876.jpg).

Preparations for rewiring the DB1/3 optics have begun. Sgan gas manifold work is in progress. Note: IOS:MP1 is scheduled for refit service shortly. We received major rebuild kits a few days ago, one to replace the kit used when the previous MP1 failed last fall. It is not likely this pump requires it; only the standard seal kit.

More materials prepared for optics refit.