New ion source interesting effects, baseline data

Data from actual runs of fusors goes here, we can discuss it elesewhere in other sub forums I will create as needed -- let me know.
Forum rules
Put data and fusor information from actual runs here. We'd like to know how well you are doing, and how you did it in some detail here. We can discuss elsewhere, this is for real reports from actual experiments only, or at least, mainly.

New ion source interesting effects, baseline data

Postby Doug Coulter » Sat Aug 12, 2017 6:25 pm

See title. I thought to try some medium frequency AC on the ion grid as an ion source. We'd been using HV DC, which worked, not down to as low a pressure as we'd like, but pretty well, though it left the plasma net negative all by itself from excess electron emission. I thought I'd try something else, and since "tesla coil frequency AC" seems to brutalize air pretty well and is relatively easy to make, well, why not?
TL;DR - it works darn well. It shows more hysteresis between what it takes to get "lit off" and what it'll hold down to, pressure wise, lighting off around 2.5 or 3 e-2 millibar, and even then only when helped by a few Kv on the main grid. But once lit, it'll stay that way down to e-3 kinds of pressures in the tank, even without help. Instead of "rays" arouund my ion grid, it just makes blobs of very faintly glowing gas (no pics right now, it's really dim and hard to capture). The AC source is around 10Kv peak here...depending. I have a choke in series with the primary of the stepup transformer and am able to run somewhere above it's resonance at the point where its capacitive reactance resonates with the choke and the primary voltage is actually about double what the drive signal (square wave from H bridge) is. FWIW, this draws more current with no load than when "lit" - the choke and step up transformer core get warm...

I took some other data (in a post soon to come) and realized I hadn't decently baselined this thing as to how for example the AC phase seen by my faraday pickups varied under various conditions vs the phase of the transformer drive waveform. So this was taking a step back so I'll be able to interpret the other data. The "EMI" trace in this is just a HV probe hanging near the ion AC HV output, so that's the gospel on what's going into the tank. The trace marked "Neutron" is for the moment, the drive signal on the transformer primary, which looks a lot different from the square wave coming out of the H bridge due to the reactances involved as described. The other two labels are what they are - faraday in the front of the tank, faraday in the back of the tank. Without tearing it down, I'm not even completely sure which one the ion grid is closer to - as the back one is near the tank vertical centerline, as is the main grid (EMI), and the front one is way up top behind the ion grid. It's even hard to get in a picture.

Here's the log text I wrote while doing this with info on what I was doing. The first two (one picture and one plot) were at a lower frequency than the later ones - I adjusted to nearer resonance to get more voltage out and easier light-off at some expense in higher power when not under load. It actually draws fewer watts under load!
Code: Select all
17_08_12_16:15:33.scopedat
17_08_12_16:16:19.scopedat

im_0004_20170812_161431.jpg
im_0005_20170812_161634.jpg
Above not lit, different scope gains, changed frequency higher nearer resonance

These lit no DC, but it took 3e-2 and ion DC to light, then took down to 1.9
im_0006_20170812_162132.jpg
17_08_12_16:22:10.scopedat

DC on:
im_0007_20170812_162413.jpg
17_08_12_16:24:48.scopedat
DC wasn't into the higher voltages for good neutron production, more like 10kv or so - current limited at 5ma - I used what we used to use for the ion DC power for this.
It did make some neutrons, just nothing to write home about - around 100k/second.

So, here's the visuals for step one - just tuning it up and with no gas present and no DC:
im_0004_20170812_161431.jpg
At the lower frequency.

16_15_33raw.png
Plotted from scope data (colors and scale different)

Note, the scope plots are from raw a/d data from the scope. Color mapping is different, but the labels are the same. This is what the scope a/d sees, and all are zero-based unlike the scope display.
If anyone wants raw data to do analysis from, I've got that - I just wrote a grabber program and a plotter program (which for now mainly concentrates on shapes, not labels and pretty stuff).
Gnuplot lets one place a cursor anywhere and then see the XY coordinates of that spot exactly. So one can find out what was when and how loud for basic human mark 1 eyeball analysis and not worry about the camera being tilted. And we know the scope sample rate, so at least we get time exactly right.
After turning up the frequency somewhat, but still no gas, no DC power and no light:
im_0005_20170812_161634.jpg
Slightly higher frequency and amplitude

16_16_19raw.png
Plot. The glitches are where the H bridge switch happens.

We see here that with no load, the primary waveform and the EMI are pretty much in phase with one another (the latter picked up by a 100 Meg, 100::1 probe near the HV output - just capacitive coupled - for that matter, through plastic) This is going to change when we get a load on this.

I put in a bunch of gas (around 3.5 e-2 mbar) and temporarily turned on main grid DC (about 30kv no load) to get it to light, then took gas back out to around 1.9 e-2 mbar and turned off the DC for now. That resulted in the below. Note that I changed gains etc to get a good picture; part of the reason there is both a screen capture and a plot for each state here - the picture shows all the incidental scope parameters better. Some things, like the coupling from the ion AC source to the faraday probes get a LOT louder when it's lit - which kind of makes some sense. The load changes the primary waveform and now the peak voltage at the output is around one of the zero crossings of the H bridge (see glitch). This is some of the info I need to be able to interpret the rest I'll be putting up later on.
im_0006_20170812_162132.jpg
Note lower volts on primary and vastly different waveform there. Supply for h bridge drawing *less* current in this state(!)

16_22_10raw.png
gnuplot of roughly the same stuff (can't hit two buttons at once, but I try)


Hitting the attachment limit for this post, I'll do the rest - the dramatic changes when there's some DC on the main grid - in a reply.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
User avatar
Doug Coulter
 
Posts: 2956
Joined: Wed Jul 14, 2010 8:05 pm
Location: Floyd county, VA, USA

Re: New ion source interesting effects, baseline data

Postby Doug Coulter » Sat Aug 12, 2017 6:30 pm

OK, here's the rest. Some things change A LOT when there's even token DC on the main grid - in this case a 5ma "whatever it can make in current limit" from the old ion supply. Depending, it's a few kV up to around 10 or so here. I guess the theory is that with even more of the gas ionized by the main grid, some things change and the distribution of signals and charge changes...well, it's a sure thing that it's different.
im_0007_20170812_162413.jpg
With DC on the main grid

16_24_48raw.png
gnuplot of same


I don't want to get too deep in interpretation just yet - this is just to baseline what to expect in further posts for this lashup. I'll need to take the scope probe off the ion HV and put it near the main grid feedthrough for most of the other measurements, as well as hook the one labeled "Neutron" back to the hornyak detector. I think we can assume near-determinism for these electronics till we have a reason to suspect otherwise.

It does really change a lot with the DC, I'll be uploading a youtube short showing that on the scope - pretty dramatic...I'll embed it here when I'm done.
Here ya go: https://youtu.be/qfAem_aDOqg


Reminder - what's AC or DC coupled, gains and all that - look at the scope pix (easier for me to put up here). Raw data on request.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
User avatar
Doug Coulter
 
Posts: 2956
Joined: Wed Jul 14, 2010 8:05 pm
Location: Floyd county, VA, USA

Re: New ion source interesting effects, baseline data

Postby Doug Coulter » Sat Aug 12, 2017 6:50 pm

I WILL analyze this to the extent of noting that the almost perfect 90 degree phase lead of the two faraday probes goes away once things are lit off. Check the scope gains, but capacity coupling would account for the lead here. Once there are ions and a lot more current on the probes is involved, you'd expect there'd bit a little transit time as well as less differentiation of the input.
The whole reason I did this baseline is because other data I got - soon to come here - showed me some kinda baffling things, but now that I know that and where the actual peak of the HV ion waveform is in relation to the other stuff...it all makes more sense (to me).

ALSO NOTE: scope trigger rates are often confusing due to that nasty glitch on the signal I'm using for a trigger...be warned. 28khz or thereabouts is the right number for most all of this.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
User avatar
Doug Coulter
 
Posts: 2956
Joined: Wed Jul 14, 2010 8:05 pm
Location: Floyd county, VA, USA

Re: New ion source interesting effects, baseline data

Postby Doug Coulter » Sat Aug 12, 2017 7:30 pm

The reason for the above is what's coming now - I got some interesting data (no huge breakthrough or anything) and it didn't make sense. So I went backwards and kinda calibrated the setup so I could interpret this better - it made no sense at all without knowing about the 90 degree plus phase shift vs conditions - especially if the transit time is just what I was trying to measure. It looked like it took *less* time than speed of light capacity coupling...well, that can't be right, so I backed up and got a baseline. Now for the strange data, which makes slightly more sense now, but likely isn't good enough to get what I want. I forgot till I looked again just where the faraday probes are in the tank vs the ion grid I'm putting high voltage AC on, and golly, they're nearly equidistant from it.
This will not do! I may have to add another probe so that I can measure 'it takes this long to go X inches, and this long to propagate Y inches, so I know how fast things go" with X and Y being different enough to make the measurement meaningful. Sigh...I hate breaking vacuum on this and waiting for it all to get clean and pure again.
At least I now have the software (having just written it) and hardware test gear (having just bought more) to make the measurement I'm so interested in once I fix the oops about where things are in the tank. I could get lucky and be able to use an otherwise unused thermocouple feed-through or something...I hope.

So, here's the skinny on the run earlier on the same day:
Code: Select all
m_0000_20170812_140837.jpg and
17_08_12_14:02:54.scopedat are with no load, vacuum, 22.4v in .591 amp, above resonance

im_0002_20170812_135120.jpg gridcam shot (there are some regular cam shots too)
Very hard to see faraday front probe even in other cam shots.

im_0002_20170812_142107.jpg
im_0001_20170812_142027.jpg
17_08_12_14:17:12.scopedat ion lit 1.6-1.9 e-2, .386 amp note changed scope
gains -
17_08_12_14:25:27.scopedat
and a different sweep on one
vid with main grid off-on-off vi_0015_20170812_142707.mp4

I'm not going to publish "run 116" unless asked. Not because it's a secret (it does have more data detail than this,, more videos and 10 hz readings across a bunch of channels of stuff) but because it's some table rows in some tables in an SQL database and without some collaboration - and a bunch of software I've published that has zero downloads (so I quit publishing more of it), you'd never make sense of all that. often the time-stamp is more or less the filename of this data, some of it I had to rename due to this or that software objecting to the characters in the name.
First some pictures of the insides of the tank. Due to view angles etc I couldn't get a picture of every grid and probe in the same frame...Oh well.
im_0002_20170812_135120.jpg
the grid cam I have all the time. Ion grid on right, faraday_b on the left with light behind it, main grid in sidearm.

Some attempts through the front glass (and sadly, dense stainless steel screen which keeps the glass from being ruined by hot electrons).
100_3203.JPG
More or less the same thing from the front.

The screen makes it kinda hard to get a good picture, but those glass doors aren't cheap, and the sacrificial glass that's here along with the screen is turning brown...
100_3204.JPG
Up and behind the ion grid, you can just see the end of faraday_f poking into view at upper right.

Here's some data from this setup:
im_0000_20170812_140837.jpg
See "code" above for the key to these. Different stuff hooked to the scope for this...which is why I had to to the first post after moving some things.

The EMI channel is in it's usual place for this - it's picking up signal from the main grid. Power to that is off, but the power supply is connected, which makes it a fairly low impedance to ground, mostly resistive, so not much differentiation phase wise.
Here's the plot from raw data of the same thing:
r14-02-54.png
gnuplot of same


Which made sense at the time. But when that phase change documented in the first post happened, I didn't have a reference to the HV output...and didn't know its peak had shifted to close to the zero crossing of the drive instead of the usual peak...so nothing made sense, and I had to back up (more next post).
The two faraday probes ARE phase shifted due to differentiation in this - just about the full 90 degrees. But that changes when there's actual ion current. That, and the fact that the relative phase of the ion AC output vs input changing at the same time, well, kinda confused me, the data didn't make any sense to any interpretation till I went back and did the first two posts here...life's like that sometimes.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
User avatar
Doug Coulter
 
Posts: 2956
Joined: Wed Jul 14, 2010 8:05 pm
Location: Floyd county, VA, USA

Re: New ion source interesting effects, baseline data

Postby Doug Coulter » Sat Aug 12, 2017 7:55 pm

The meat here. Data with the ion grid "lit off":
im_0001_20170812_142027.jpg
Ion grid lit off.

im_0002_20170812_142107.jpg
Sweep change

Gnuplot of the raw stuff:
r14-17-12.png
Plot. Note distortion on sines from ion loading

r14-25-27.png
faster sweep


Some interesting changes here depending on whether the main grid has DC on it. When it does, the faraday_F gets a lot louder for one thing...the ion grid is maybe modulating ion flow from the main grid to the probe?

"Who ordered that?". I was just looking for transit times. It's been my theory for a long time that even if we put 50kv on a fusor - we don't get anything like that on the ions due to plasma field neutralization and other effects. A long time ago (2009) John F was here and we kinda measured some of this - on the order of 5 uS flight time across the tank. FWIW, I'm still nearly at that number, maybe 2.8 uS, but...with the inaccuracies caused by other things, maybe it's the same (likely) or will be with the big power on the main grid. And now I should be addressing the inaccuracies in those other things (like what are the distances between things in this lashup geometry so I know what a time means in terms of speed, and therefore particle energy).

People tell me I should post more, I'm trying, honest. Sometimes it takes awhile to have anything worth posting. Not all science is some exciting action-adventure movie or something that solves the crime with a DNA sequence during the commercial break (of by shouting enhance). It's only exciting at the end, or if you simply enjoy the journey as I do. So, if the TL;DR guys don't appreciate this, I guess they'll have to settle for being last in line.

Here - most scientists don't publish real data till they've analyzed it for 6 months first. This I've not even analyzed. So...have at. Any of the regulars here who have comments, bring them on, I don't have a clue on some of this at this point other than "I need more measurements that are kinda independent of these - maybe with different probe locations".
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
User avatar
Doug Coulter
 
Posts: 2956
Joined: Wed Jul 14, 2010 8:05 pm
Location: Floyd county, VA, USA

Re: New ion source interesting effects, baseline data

Postby Jake Gray » Tue Aug 15, 2017 3:04 pm

I don't think you have to post more, but some of us get a bit worried when we don't see anything for a couple weeks. I check in most days, and am now used to the occasional week between posts. I think everyone is quite happy for you to spend your time however you see fit, and I imagine that isn't spending all your time posting.

However, a canary post if you haven't posted in a week, even to just say "Nothing to report" would ease the thoughts of either you blowing yourself up, irradiating the whole hillside, or black suburbans rolling in and taking everything.
Jake Gray
 
Posts: 22
Joined: Wed Sep 15, 2010 5:29 pm

Re: New ion source interesting effects, baseline data

Postby Doug Coulter » Tue Aug 15, 2017 5:05 pm

I hear you, Jake, and it's not you I was going on about - it's the kids on youtube...who want endless free entertainment (heck, so do I but realistic expectations, y'know).
And who aren't aware of the issues in "The Mythical man-month". Science isn't linear...boredom (on their part) seems to be, educated by TV that we're going to solve the issue during the commercial break. EG, I was just doing the "grumpy old man" shtick. We're working pretty hard to replicate some of the earlier "magic" with some limited success so far. Rest assured that anything remotely risky to my health is done remote control, even though it's a PITA and far slower. This can't really blow up - .02cc or less of fuel at a time here...and it can't chain react as any energy it makes simply flies out between the sparse fuel atoms mainly. The men in black...I'll just keep my cricket loaded.

We have learned some interesting things about the response times of plasma based on initial ionization that I didn't realize before, doing this. Believe it or not one can blow a full snot auto spark coil (in the 50-75kv region) pulse about 30uS long into the main grid and if it wasn't lit some other way within the last < 100 uS, it won't even draw current even if the ion source is on. You gotta pull them in with some DC or something first. That is to be tried soon with something fancier than a spark coil...remotely(!) - it might work.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
User avatar
Doug Coulter
 
Posts: 2956
Joined: Wed Jul 14, 2010 8:05 pm
Location: Floyd county, VA, USA

Re: New ion source dox and more info

Postby Doug Coulter » Sat Aug 19, 2017 12:37 pm

Before sealing this up...
I'm using a really nice little HV stepup transformer, coils found by Bill, I didn't wind these or make the forms - and these are indeed nice and have a pretty high self resonant frequency given the stepup.
I happened to have the core from some old (large) computer switcher (not a PC!).
Because we're making over 20kv pk-pk, there were corona and arc problems. So, prying off the original secondary terminals, gluing some old polycarbonate in the right places and so on solved most of that (we've not tested to extremes yet, but so far...). It looks like this. I'm using banana plugs for HV which sounds dumb but where they are their "pointiness" doesn't result in issues with corona or arcing and it makes things easier to fool around with.
100_3205.JPG
Here's the step up transformer

This thing did NOT like the square wave put out by one of my old H bridge switchers (pictured later) so I tried using a series L and running it somewhat above self-resonance. In fact, I happened on a combo that is "net" in resonance at 27khz (transformer alone was 21 khz) with a series choke. This all has the interesting property of drawing more power when unloaded than with a gas load and it lit off, I'm guessing due to core losses - the choke gets quite warm and maybe other things I wouldn't put my hand on in operation. I used the same core to make a choke for each lead since it's an H bridge drive, they can share things if the phases are right (they are). But in an ideal world I think I'd use a bigger core. The driver looks like this (run off a bench power supply right now).
100_3207.JPG
The old H bridge design and series choke

This is run off a bench supply and at 20v input 9which is 40v pk pk output to the transformer nominal, more due to the series resonance) draws around 600 ma. Under gas load, lit off, it drops to around 350 ma..I have a probe on the square wave to trigger the scope for other stuff...under no load the output is more or less proportional to the input voltage.

This is all lashed to the "ion grid" feedthrough part of the fusor apparatus. I'm using BN inside of pyrex here as well as for the main grid, but here we are using 1" pyrex so it won't take quite as much voltage (no issues so far, the main grid feedthrough is very overbuilt for current conditions). inside that nice (and expensive) cat 80 pvc under the brass screen is also a 50k 200w resistor for ballast, which I've not used in a long time. There is a bypass lead of glass insulated copper pipe to the end, so I can plug my HV into either direct or the series R. As time goes on, I might remove that resistor and shorten up the pipe. FWIW, this sched 80 PVC is really nice stuff, and is thick enough to thread for setscrews. It just fits over nominal 2.75" flanges and a couple screws will hold it on as you see just fine.
I use this on both grids, and in the case of the main grid, one could wind a primary coil for a linear transformer with the secondary on smaller pipe inside...with my 8" shielded PVC over all for safety and lower emi into the measuring gear.
100_3206.JPG
Overview of ion grid stuff



In some tests we ran earlier in the week, with this thing making ions, a couple of points of interest - one is that we could run lower gas pressure and stay lit off than ever before, we got down to the low e-3 millibar range easily. But...even then, we could not drive the main grid up to our usual 50kv at our usual 10ma current limit, which are the conditions most of our other numbers came from. If that ion grid was lit with this AC source, we had too many ions (too such low gas pressures it finally wouldn't stay lit) and would have had to use much more current (grid heat issues!) to get to 50kv and that wouldn't necessarily be directly comparable even with scaling to our other numbers (eg, can't do good science this way). Sooooo...that's why this was all apart to take pix of in the first place. I added a bananna jack and some further insulation to the transformer secondary so as to put either a large ballast to ground on the LV end or maybe even inject some DC there - at least try some more things. It might be that we need lower AC, or a "squishier" higher impedance situation on the drive end so that we can be lit off but not be so darned effective at making so many ions - which amazes me in such long mean free paths.
This actually works too well! This is not the main thrust of my work - I was looking for some "edges" in signals to measure transit time kinds of things here - but hey - better is better if we can tame it nicely. Work in progress!

Interestingly, we also observed that under these lower gas pressure conditions that the location of most of the main grid heating moved towards the front of the grid. All our earlier runs heated the main back-plate of it primarily. These all heated up the front ring and rods much more. If we get to a place of more neutrons/watt - this is desireable because it eases the heat load on the feed through and would only heat things that can easily take quite a lot with no damage. We didn't get to a lot more neutrons as we just couldn't get main power over around 30kv with our current limit.
Yes, we can run a lot more current (we have 40ma available at 50kv), but didn't bother, no point in melting stuff...
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
User avatar
Doug Coulter
 
Posts: 2956
Joined: Wed Jul 14, 2010 8:05 pm
Location: Floyd county, VA, USA

Re: New ion source interesting effects, baseline data

Postby Doug Coulter » Mon Sep 11, 2017 5:02 pm

Continuing on with this stuff, last time we couldn't get up to the high main kV required to get into "good neutron production". For various reasons, I didn't want to just set the main HV current limit via the knob on the supply alone - it wasn't remoted, but now it is (up to 20ma since I only have a 0-5v dac and it would take 0-10v for the 40ma or so full output - which I can't use anyway, see video).
Lo and behold, when I get up to the real voltages, via using even less gas pressure (because it will now stay "lit" at lower pressures) and more current - because even at the lower pressures, there are more ions in there it seems - it works darned well.
I tried compositing the gridcam and scopecam videos along with room audio and a couple screenshots of the plots...but the scope cam is still dropping frames it seems, even when I'm not previewing, and gets "ahead" of the other stuff in this video...I have more work to do, perhaps if I'm lucky I can cut the frame rate down on the pi and it still composite correctly? We'll have to try something here - we are already using a fast USB3 stick to write video to. Lower frame rate? Either less or more compression? Hard to change the resolution and still have the field of view we need...something must work...I managed to have a fairly stable version of openshot (2.3.4) to composite this with...nice, easy and fast if you have a non crashing version.

https://youtu.be/Oc15KSMrTxo


Note the changes in the faraday probe signals vs the DC inputs. (EMI is a proximity coupled probe to the main HV signal - and blew off screen at the end). At one point I switched to triggering on our fast neutron detector (no time-smear due to moderators) to see if I could discover a correlation between our ion generator AC and when the neutrons came out. More study needed - it's not obvious if there is a correlation, to me, yet.


Here's the plots from the run. Significant here (well, to me) is that other than the videos, which are written inside the pi camera setups till a copy after the end of run, all this is going to a database on the new synology NAS (DS-416) in realtime and it's working right - no errors attributable to that. This is saving me the hassle of keeping a couple databases in a realtime sync configuration to ensure I get data right up till the meltdown (or whatever might crash the proximate machines) and, well, the NAS has ~~ 10gb free for this.

Holy crap, I'm so behind the times...I didn't catch that instantly. The NAS has 10 TERABYTES free (puke green?) :oops: ...Don't think I'll be running short anytime soon, as I'm using .5 tB for, well, everything else I've collected up till now (I'm not doing pirated movies obviously, but I do have 7k or so CD rips - of my own CDs, multiple virtual machines and you name it else).

So, data, please!
Qplot.png
The meat of the biscuit. Good but not crazy-good.

Decent Q for our stable modes, not super fantastic, but a little better than usual. I didn't push the low limit of gas pressure, which seems to improve Q (and a lot of other things, like where the heat goes) on this run.
Here are the other plots from the database. This isn't all we get, just what we like to have plotted. We can do fancier things with that perl program that does the Q plot (such as insert code on a per sample and per axis basis - so we can make one "time" and the rest whatever, as well as make scatter plots with that one)
FusorPowerIn.png
The power inputs. Our ion source is now negligible in watts...about 330 ma at 20v in to that.

I've made the main supply current limit remoteable, and was mainly testing that function, as well as "just how much is it gonna take to get to our usual 50kV?" We make it easy, and with less gas, we might make it even easier. Heat seems to move to the end of the grid far from the feedthrough with less gas too - and that end can take white heat continuously.
RFrads.png
The radiation counters

So, mo power, mo radiation. Not a surprise. I didn't check activation as the other parameters were all over the place - on purpose, this wasn't "that kind of test".
FusorPressure.png
Lower than usual pressure - normally won't stay lit at less than about twice this (indicated)

This is maybe pretty significant on a couple levels. Being able to run lower pressure seems to make everything better. This new ion source makes ions so effectively and efficiently we can run half our usual minimum, and it looks like if I push it, we can go lower still - didn't even try this time. Also of significance is that we now have so many ions, it messes up the pressure gage - turning on the RF ion supply makes the gage read 20%+ higher than with it off...I guess it expects its own ion generator to be the only one around (and it IS behind some tight mesh grounded screen).
Remember, according to Pfeiffer it reads around 2x high on hydrogen anyway...

So, database move test is a success, variable main power current limit a success...maybe we can go more places and do more things now.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
User avatar
Doug Coulter
 
Posts: 2956
Joined: Wed Jul 14, 2010 8:05 pm
Location: Floyd county, VA, USA


Return to Run Data -- just the facts please.

Who is online

Users browsing this forum: No registered users and 1 guest