Keerthi suggested using 16O5+ for optimizing the source. I did a tight mass scan in that area, and 16O5+ is clearly visible. I will use it for some source tweaking. Also, I used Gabe's calibration program to slightly adjust the values of the two constants. There are some 10nA of 16O5+ on FC6 presently. Final settings for today, etc. are attached below.

IOS mass scan if faulty. These is a manual scan from mass 3 to 4

Const22 = 0.04187  adjusted to mass = 4

A/q               FC6           X          Y 

3.0075        8.14e-8      398  237

3.1222        4.93e-10   398  237

3.2064        6.24e-7     398   237

3.2613        1.05e-9     408   237

3.3395        2.29e-10   408  237

3.4072        5.6e-10     408  237

3.5089        3.36e-8     408  237

3.5600        1.4e-10     408  237

3.6069        1.86-9       408  237

3.6436        8.46e-10  408  237

3.7514        4.02e-10  418   237

3.8387        4.37e-9    418   237

3.8883        3.43e-10  418   237

3.9416        1e-10       418    237

4                   1.1e-6     418    237       500  

A/Q            FC6

4                1.1e-6

4.25          8e-10

4.34          1.2e-9

4.42          5.5e-9

4.51          2.59e-9

4.58          1.7e-10

4.66          1.7e-10

4.74          1.7e-10

4.85          4.6e-10

5.0            1.36e-10

5.07          1.5e-10

5.13         2.69e-10

5.25         4.89e-10

5.33         9e-7

5.39        3.0e-10

5.56        3.3e-10

5.67        1.12e-9

5.7          5e-9

5.83       4e-10

5.92       2e-10

6.000     1.85e-7

A controls issue with IOS:BIAS was found yesterday. Controls people resolved it today. MWS source was switched over and prepared for Rb beam. Leakchecking done: tight. Source should pump for a little while longer before energizing. At present, leak detector is attached to the IOS roughing line. Pic attached with IOS:BP1 alternately online and offline.

Note: Source gas hand valve is CLOSED.

A controls issue with IOS:BIAS was found yesterday. Controls people resolved it today. MWS source was switched over and prepared for Rb beam. Leakchecking done: tight. Source should pump for a little while longer before energizing. At present, leak detector is attached to the IOS roughing line.

Later... Noticed that MCIS:TP2 was tripped off. After a couple of tries, it restarted okay. Hmm...

Source switchover in progress on WP#2010-10-12-1. Magnesium material installed into MWS. Pumpdown in progress. Leakup rate OK. Turbos on.

Later... Pumping going well. at 1e-6 by ~16:00.

Source conditioning most of today, to 59kV. Striptool attached. Reset to 26Mg tune at ~16:00.

Source is running nicely. Hand-off to ICR occurred ~Wednesday night. Setup done overnight. 26Mg (PE is now on at nominal value) is selected presently; blue trace on Stripchart.

A couple of weeks of 17O3+ to DRAGON ended yesterday with a photo finish. Supernanogan went off at 10:00. Preparations for 18O began. Main event for yesterday: Replace IOS:TP7. Edi Dalla Valle reported that he had just received a V550 with Conflat flange. "Our timing was perfect." It is working well. The system was under vacuum again by around noon, and pumped overnight. This morning IG1 was ~5e-7 Torr and IG4 was ~2e-7 Torr, where those two gauges were the other way around previously. We attempted to do a leak check, but could not get it coordinated in time. So by 15:00 we chose to start the MWS and hand over the beam to the users.

Present MWS source gas setup: enriched 18O attached in two places; the straight-through path is open, while the calibrated leak is closed. We approximated the appropriate pressure on the regulator, allowed it to bleed down, then reset it to slightly under. The bottle valve is open. The bottle pressure is 150psi right now. At this rate, the cost of the source gas is about $200/day.

The source stayed up overnight just fine, with a little 25Mg beam on FC6. This morning I did a few mass scans to get a fix on Mg positions. Short story: There are some 3nA of 25Mg on FC6 presently, with things less than optimal. Stay tuned.

Attached is an early graph of Mg beams produced with the MWS almost exactly five years ago. Best I could find for now.

Later... Tuning went well. I ultimately had to tune in the ICR due to network response outside as people came in, etc. There are some 10nA of 25Mg on FC6 now, and the tune is set up for RFQ delivery. Snap: 090804_1240.snapiosfc6. I tweaked the upstream vertical steers slightly afterwards. The front-end differs from Rick's numbers by a bit, but it's necessary to keep down spills onto optics and get the beam through. I'll attach the differences below. Meanwhile, here are stripcharts of FC6 for the morning. In the latter part you can see where I turned down the microwave power from 600W to 500W. Slightly more than 500W seems about right for equilibrium. But to avoid boiling let's leave it at 500W for now.

A decent emittance scan is in the ISAC elog, albeit I ran it with slits closed down, so it should be repeated at some point with slits open.

Well, so it goes. As I was penning a note for OPS, the source tripped. It easily reignited with a little extra Ne. I left the flow slightly higher, from 1.1 to 1.2ccm and the PE at 41V.

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.

So... there evidently was a power bump overnight, because the stability power supply was "disconnected" from the system. This happens every time there is a power bump. It's a serial port thing. Meanwhile, the source also tripped. Upon restart, nothing was the same. This morning, we found that Q3 was current-limiting on one element. We have asked Rick to develop an alternate tune for us.

Keerthi did some source tuning early this morning. We since shut it off for the swake of Q3. I have restarted it now temporarily. Here is an emittance scan with slits open and Q3 off. Now we will shut off again to prepare Q1 & Q2 supplies for new numbers.

Tuning...

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.

MWS source switchover yesterday was successful. Leakchecking went well. A small leak on the intermediate section sealed with a snug on the two bellows fixing bolts. The microwave window required cleaning. It tested leak-tight. All good. Pumpdown curve to come. Meanwhile, source was restarted last night. First 85Rb is on FC6 presently. Although OLIS has run Rb beam in the past using the SIS, this is a milestone for the MWS. Development to proceed today.

Later... Here is the pumpdown curve to last night. Base pressure reached less than 3e-8Torr, which is a very good pressure for the MWS. Prepare to shut down leak detector, which has been pumping on the roughing line overnight.

Later... First piece of a comprehensive mass scan. Brings a tear to my eye. Save: 101029_1125.snapiosfc6

Later... Scans completed. Data file. Among other things, the following isotopes were observed:

A/q	Current	Isotopes
14	1.5e-09	14N
15	6.0e-11	15N
16	1.3e-08	16O
17	6.0e-10	17O
18	6.5e-09	H2O, 18O
19	1.7e-07	19F
20	1.3e-09	20Ne
21	7.0e-10	21Ne
22	1.4e-10	22Ne
28	4.2e-09	28Si
29	2.0e-09	29Si
30	4.2e-06	30Si, 60Ni+2
31	1.9e-08	31P
32	4.2e-07	32S
33	1.0e-09	33S
34	3.3e-09	34S
39	7.5e-10	39K
41	5.0e-11	41K
44	1.0e-10	44Ca
45	1.6e-10	45Sc, 90Zr+2
46	6.5e-08	92Mo+2
47	3.2e-10	47Ti
48	7.0e-10	48Ti
51	3.0e-10	51V
53	9.4e-10	53Cr
60	6.5e-11	60Ni
67	4.0e-10	67Zn
69	1.3e-10	69Ga
85	6.5e-10	85Rb
87	2.3e-10	87Rb

Spreadsheet
Scans Details

Attached is a separate scan in the region of 40 to 45, done in two directions. Data file (raw).

Leave 85Rb on FC6 for the weekend, or as long as it lasts! !1.3nA presently with 2.5mm slits in. I have increased the support gas flow slightly.

The source stayed up steadily over the weekend, with 85Rb on FC6. Not a lot of current, but pretty good for a first pass. More development today. Source settings shown below. As previously noted, the 2.5mm slits are selected. Also, the present IOS tune is for effect, not by the book.

Next up: Try some variations on the source setup.

85Rb on FC6 overnight. After restarting the source yesterday following development, the beam intensity came back, but it's slightly unstable compared to before. Mag stability program is active.

Later... Work with the source for a while. Improved. Stripchart attached. Time will tell. Save: 101102_14:30.snapiosfc6. Turn it over to ICR now.

Tuning has been on-going through the day. Here are a couple of emittance scans taken in-between heartbeats. The first is zoomed out, the second zoomed in a little close. We managed to sneak in a third also.

So... we have had this on-going problem with intense Mg beam coating our optics. Keerthi found a good recipe last week with PE on and a somewhat large support gas flow. We have been running with several tens of nA since. Since yesterday's trip, I have been gradually lowering the PE from my initial value of 100V to 30V presently with about 10nA on FC6. Beam looks like it will be very stable, and the EE will maintain indefinitely like this. The first test: Marco just made overtures to use the beam for checking TIGRESS tune.

As noted earlier, the MWS beam dropped out at some point after yesterday afternoon's playtime, due to insufficient PE. Plasma was lost. I restarted the source remotely. The present combination of Ne flow SP = 1.2ccm and PE = 48V works well. Plasma will persist regardless of Mg presence or PE setting. That's a good thing. Then using the PE we can control how the plasma ionizes the Mg material. Note the attached stripcharts. At the lower PE settings, the Mg loading on the EE is much reduced and indefinitely sustainable at those levels.

Presently the source is off for Supernanogan cart installation. We will have it in and buttoned up by around noon.