Today we vary source gas pressure.

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

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.

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.

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.

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.

CUSP source was off for the night, following Keerthi's development. He had increased the current on FC6 and the arc current substantially. More later.

Meanwhile, restart source and let it condition for a bit.

Later ~14:00 we have 200enA on FC6. Source gas is shut off presently. Time for some mass scans. Strategy: Identical mass scans without and with source gas, to check background ratios.

Later ~15:00: Mass scans with source gas closed complete. Note: IOS pressure is 5.25e-7 Torr, slightly higher than earlier. It was ~3e-7 this morning. Possible leak in gas manifold fitting?

Later ~16:30: Try out different combinations of gas and source parameters. We cannot get the gas flow low enough so far. Optimal source:

Fil = 130A (3.1V)

Arc = 67V (0.9A)

FC6 = 7.5eµA 4He2+ & H2

Note: Increasing any of these parameters much above these numbers causes the bias to current-limit at 1mA.

Later ~18:00: Check beam current at H+ and H3+:

FC3 = 140µA

FC6 = 1.42A at A/q = 1 i.e. H+

FC6 = 149enA at A/q = 3 i.e. H3+

FC6 = ~80µA at A/q = 4 i.e. 4He1+

FC6 = 1.78eµA at A/q = 16 i.e. O+

FC6 = 2.29A at A/q = 18 i.e. H2O

Plot 1: FC6 current for last evening.

Plot 2: Scan 0 to 5 and back.

Plot 3: Scan 0 to 40 (same parameters as yesterday).

Plot 4: Scan 0 to 40 and back.

Plot 5: Combo development session stripchart.

Fuse for FUG power supply obtained and installed. Source is up and warming up. ~100enA on FC6.

Later ~14:00: Tweak things up. We now have a more stable 380enA on FC6. IOS:IG1 = 7e-7 Torr.

Later ~15:15: Adjust source gas metering valve "just a little"... and effectively vent the tank. This needs work. Recover, restart source. Wait and watch how beam responds to gas pressure. See attached stripchart.

Later ~16:00: Increase arc power & filament current. Arc current jumps from <100mA to >3A. Also increased current load on bias & EE.

Arc = 135V @ 3.0A

Fil = 3.25V @ 138A

Bias = 28kV @ 788uA.

EE = 2.07kV @ 4.9mA

PE = 97V @ 149mA

Gas = 0.41ccm

First mass scan attached with arc current at 3A.

Second mass scan in progress

The OLIS cage was open over the weekend. IOS pressure is in the 4e-7 range, with source gas manifold closed and external helium bottle slightly opened through the metering valve. Today's game plan is being discussed presently.

Later ~11:00: Restart source. 50enA of A/q=2 at FC6. We had planned to restart with background source gas, but pressure is too low in gas lines, and a plasma is forming there. I have opened helium on gas manifold, with flow controller at zero SP. ~0.5ccm result. Background pressure ~4e-7 Torr; present pressure = ~1e-6 Torr.

Later ~15:00: Tweak source and IOS. Presently we have 0.5uA of A/q=2 on FC6. Big contributors: EE + vertical steering. Attached pic shows beam since ~startup this morning and a flurry of activity around midday. I will begin some source gas tests shortly.

Later... Source gas tests part one completed. Solenoid valve upstream of flow controller closed, then flow readback, pressure drop and FC^ noted until source gas line became a "neon" lamp. Part two barely begun, when FUG blew a fuse on normal startup and (how embarrassing) we don't have replacements handy. Also, upon opening the RG helium line, we found it was tricky to get a good pressure. We have it now. Fuse will have to wait until man~ana, though.

We received back the source this morning. First order of business was to take some EOB scans. See earlier entry. Then we shut down the source and opened the cage. Water leaks fixed. We had agreed with ICR to let them go for the sake of continuous beam to our users, so that we could avoid switching off the source. All done. There is a little weeping on one or two of the source body screws, as expected. As a practical matter, we aren't going to fix these.

Research-grade helium gas and lines hooked up today. Metering valve installed inline. Lines are pumping now. One-pass helium purge done.

Note: We had first beam today from the I3 development H- ion source, presently set up in the CRM on a borrowed test stand. Yes!

Mike declared successful EOB this morning. "Best beam I ever used" or something like that! EOB emittance and mass scans attached. Note that slits are at non-standard positions for 5mm gap.

Now we are going to open the source for some maintenance and continue 4He2+ development after that.

Beam was idle overnight. We took the beam for a while this morning, and ran a mass scan. We opted to not go into the cage to install helium gas lines or fix water lines, because it would mean switching off the source. So we will do the gas tomorrow or so, and fix the water leaks then too.

Note that the separator field is up about 4G from this morning.

The source ran well overnight and today. There is an issue with an ILE Faraday cup. Tuning is ended for today, and beam is on FC6.

By agreement, we are providing OLIS beam to the Beam Delivery group for the purpose of checking out transmission in the 8pi line. We have set up a 20Ne1+ beam at 28keV. There are some 3nA on FC6.

Here are optics numbers for IOS section:

Quad	    Rick's values	   Optimum values

Q1		1331V			1666V
Q2        	 661V			 580V  
Q3		   0V			   0V
Q4		 732V			 732V
Q5		   0V			   0V
Q6		1770V			1770V
Q7		 660V
Q8		 965V

An initial emittance scan is attached, raw and filtered. A higher resolution follows. Surprisingly, it is grainier than the earlier one. Slits are at 5mm setting.

Milestone note: The commencement of using this beam today at around 14:00 marks the first time in ISAC history that a filament ion source is used to deliver a beam to a user. Hooray!

The CUSP source ran well overnight, notwithstanding local control of source power supplies. Filament supply had dropped to 115A this morning, which is approximately 10A over a 16 hour period. Attached are charts of 4He2+ beam on FC6, an archive chart and a fast stripchart of the last six hours. Shortly we will begin setup for an 8pi shakedown run today.

OLIS beam to 8pi is planned for tomorrow. A 20Ne1+ beam of ~3nA at 28keV is the agreement. The 8pi line diagnosis is likely to take a couple or three days.

We completed the services by end of last week. Of course they could always be better, but everything is fine for this iteration. Keerthi had a first beam out of the source (to FC3) on Friday, with no source gas flowing. Today we started it up, and got first beam this morning. First 4He beam was observed on FC6 at around 10:45, and 4He2+ a few minutes later. Plenty of development to go, but it works.

We completed the services by end of last week. Of course they could always be better, but everything is fine for this iteration. Keerthi had a first beam out of the source (to FC3) on Friday, with no source gas flowing. Today we started it up, and got first beam this morning. First 4He beam was observed on FC6 at around 10:45, and 4He2+ a few minutes later. Plenty of development to go, but it works.

Later... Light it up and tweak. Filament is at 125A and arc at 100V. Bias is 10kV. 4He2+ on FC6 = 580enA. Save: 091130_1600.snapiocf6

Let it sit for a while. Filament p/s is running in local and V regulating mode for safety.

Latter... Stripchart attached of beam and playing over the last hour. It would be nice to have a loop adjusting the EL against SK-MSBR, which seems to track beam at FC6 quite well. Source on for the night to condition. ICR apprised.

Arc power supply replaced. Water leaks down to one or two pinholes on source body; manageable. Minor mechanical in progress.

Vacuum Group experts looked at IOS:BP1, reported noisy for a minute yesterday. Basically, keep a watch. It should be okay to Shutdown. We will order a seal kit and negotiate for a backup scroll pump.

Later... Electrical is complete and tested. Arc and filament power supplies run in local mode only, with insulated knob extenders through the cage wall. The source is ready for testing. As noted yesterday, source gas is off presently.

In a little while, I will secure and enable the cage and ask ICR to perform an IOSIOC reboot test for us.

Services completed today. There are still some teething pains, particularly the arc p/s as noted earlier. But we did have some beam on around noon for the first time, using neon source gas. Plan is to install helium source gas at the last minute, after all other checks, particularly leak checks, and a background calibration are done.

Later... IOS:BP1 made some clanking noises about a half hour ago, something like a car I used to own. Pump vacuum bumped at the time. See stripchart below. Quiet now, and pressure okay. ICR is keeping a watch.

Later... I closed off the source gas hand valve at 18:00 for the night, in case the scroll pump breaks and ICR has to shut down the turbos, etc.

Arc power supply does not hold any voltage.