Standard counter now available

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Standard counter now available

Postby Doug Coulter » Tue Sep 20, 2011 3:43 pm

As we've discussed elsewhere here, there is a need for some kind of standard that lets us compare results between labs that might be across the earth from one another. From that thinking came the "standard counter" project, documented on some other threads on the board, for the various parts (hard and software, PC and embedded). Joe Jarski and I have formed a collaboration to make this and other things that sometimes seem to be holding others here back, under the assumption that those people just want to get on with their main research, and not have to dive so deep into the details of what it takes to make a quality, reliable product. Our plan has been to do this completely "open source", and we feel that if you want to build your own of any of these things (we have a long list of things to come), that's fine with us. The point is to serve the community and collect good karma, not to get rich off this (as if anyone here was going to make us rich!).

So, this is our first product outing, though there are a few more in the wings coming soon.
StdCtrFinished.jpg
Standard counter, serial #1


This is a pancake geiger, shown here with the protective cover (and beta stopper) on the tube. It is USB powered, so it requires 5 volts on a USB jack to run -- and it's a lot nicer when you use it with a computer and plotting/logging software which we also provide. The particular pancake tube we've managed to get 10 of is optimized highly for beta radiation over all other types, making this perfect to count silver or indium after activating it with your neutron-producing device, and that's its main intended purpose. It's sensitive enough to count background, which it counts in the low 20's of CPM in a few locations I've taken it to, well off the ground (the rocks around here are a little hot). However, the specialty of this is superior beta sensitivity. While it counts less background than the larger Geo pancake, it counts a beta source a lot higher. The gamma to beta ratio is greatly enhanced in this, as I will demonstrate on this thread somewhere. I measured this using an "official" plastic encased Cs-137 .25uC source -- something that emits one beta and one gamma per decay (no alphas, and both the betas and gammas are monoenergetic). With the beta shield in place, this counts around 1k CPM. Without the beta shield, it counts closer to 30k CPM -- so it's about 30x as sensitive to betas as to gammas, making it ideal to count sample activations against a mostly-gamma background (the usual situation).

Here's what it looks like on my dual monitor setup.
StdScreen.png
Screen shot of a demo run with background, and a source with and without a beta shield in place.


You can see when I did what easily on this plot, which is log Y so you can even see the background in the presence of the 30k cpm points. Gnuplot lets you get numerical data back by placing your cursor over a spot, and the cusor position, normalized to plot scale is displayed at the bottom left (I didn't do that this time). If that's not a good enough record, then it will also log the raw data from the standard counter.
9_20_2011_16_19_58.log
Log file, linux text (eg just \n, as a line terminator nor crlf as windows likes -- you may have to edit to get it to look right in windows).
(11.82 KiB) Downloaded 976 times


Later versions of the open sourced perl PC code will run on windows (and get the line terminations right for that) as well as allow inserting into a MySQL database on any host in your network.
The idea is to build up an overall physics lab data aquisition and data mining facility at pennies on the dollar compared to what's out there now, and tailored for fusor (or other nuclear) type situations. The sharp eyed might have noticed an extra set of colums in the log that are all zeros, or that BNC jack on the box. We provide another counter input channel, ttl type levels but AC coupled, meant for negative going pulses. This is so you (or I) can attach a neutron counter and get both on plots and logs, all nicely in time-sync.

The provided host perl software uses very little of a PC - it was carefully done to never spin in a polling loop waiting for a second to expire, for example, and it uses little memory for reasonable length runs. Just about any laptop is overkill for this.

We are not using much of the PIC microprocessor here at all. It's loafing at about 1% cpu load most of the time, and most of the memory and I/O are "left over". That's on purpose. The main board we designed (I did the schiz, Joe did the PCB layout) has quite a lot of capability, and will be used in other things we make available here. Here's what it looks like inside.
StdCtrGuts.jpg
The guts

Note the dual row of "spare pads" on the edge of the board. Thats' the leftover IO from the PIC 18F4550. It includes regular digital IO, PWM outputs, A/D inputs, interrupts, I2C bus, and power.
This board can be plugged onto application specific other boards, and either power them or be powered by them, providing a uP and an PC interface that can really move some data.
You'll notice that we designed this in modular fashion -- all the geiger-tube-specific stuff is on its own board, so if that should change for some reason, you only change that part.

As we have only a limited supply of these excellent Russian tubes, and since this is really specialized for counting activations that make betas, we'll price it like this:
$200 + shipping for all comers
$180 for board members or fusor.net "neutron club" people.
$150 for board members that have an actual neutron producing thing to make the proper use of this with.

These will come with a calibration source (and we will log the response here by serial number) and a sample of silver foil to test-activate and count. We are using a thoriated lantern mantle for the calibration source, since one nicely covers the active area of the pancake, as does the silver foil sample. You'll have to make your own neutron oven, a sample is described here.

If anyone just wants to make their own, feel free. All the information to do so is posted on various forums here already, including complete source code for both ends of the communications link. I'd like this to be GPL-v2, meaning mainly that if you make some improvement, I'd like you to share it back to us all.

(note to self, edit and put links to the other stuff about this here)
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.
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Re: Standard counter now available

Postby chrismb » Sat Sep 24, 2011 12:24 pm

It's a thing of beauty, guys. Well done!

Have you figured out shipping costs abroad?
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Re: Standard counter now available

Postby Doug Coulter » Sat Sep 24, 2011 2:21 pm

Thanks Chris. To the extent it's beautiful (and it is), blame Joe -- that's his doing. I just make 'em work. And, along those lines, here's the results of a test I just ran.
5 min timed fusor run, starting at 20 sec, ending at 320 sec. I then put the silver foil from the neutron oven on the standard counter and let it stay on there till about 500 sec, then let it count background (sadly, I'd left a thoriated welding rod on that bench, which raised the background about 30 cpm or somewhat over double my normal). At any rate, here's the shot:
Screenshot-4.png
Screen shot from real live test of standard counter, with activation of silver foil after 320 sec, then background.


Fusor conditions were 2.2-2.5 e-2 mbar "old" D (had been in there awhile, had a little air too).
40-50kv, 10-15ma. Neutron oven as depicted elsewhere here, sitting on sidearm over grid.

You can see where I tried to let out some gas to get the volts higher under the current limit I had set, and made it go out, then a bit of fooling around to let in too much gas, and try to get the magic number again. This shows up more on the X rays than on the neutrons as long as the thing is running, but you can see it both places in sync. On the geiger plot, I placed the cursor over the high point of the silver count, right after putting it on there, and you can see the seconds and the counts/minute there. This appears to be precisely as sensitive as the one I'd been using, a larger 2" pancake we got from Geo, but which wasn't optimized for beta -- I know because I "baked" both my old thicker and larger sample and the new foil sample (same as will come with this counter) at the same time and counted them both. They tracked! Since this is a log plot, you see any simple exponential decay as a straight slope.

The neutron detector was the Hornyak I'm working on, also depicted elsewhere (I'll be adding posts to that to show the final build and yet another preamp -- best one yet). It's "deef as a post", but plenty good enough for this. The He3 and boron tubes were going "ssssssssssss" and I didn't count them, they'd have been way larger numbers. But a fusor is "loud" so the monitoring detector can be a little numb and still be fine. I did note that the hornyak can "see" the X rays when I hold it over a leak in my lead shielding, so for some people that would have to be shielded, or they'd have to shield their reactor (you know which you *should* do, doggone it -- RichardH)

In my case, all I have to do is keep it outside the lead. Here's what it looked like for this run.
HornyFusor.jpg
Hornyak detector pointing at fusor core




I don't know shipping to UK until I go to the PO and ask. I shipped JonH a small book (Halliday) and that cost something under $20 - via "US Mail". Fedex would probably be in the same range and get it there with less damage? I'll ask them.
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.
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Re: Standard counter now available

Postby Doug Coulter » Sat Sep 24, 2011 7:47 pm

OK, here we go with a real decent fusor run. Just about exactly 10 mins, but no guessing, because the log file shows all :mrgreen:
Screenshot-5.png
Screenshot of standard counter info, good fusor run

9_24_2011_20_4_20.log
Log file produced by std counter (linux line terminators, you might need lin2win or a good editor to get it to look right)
(60.18 KiB) Downloaded 914 times


Fusor conditions:
1.6-1.9 e-2 mbar on pfeiffer pk251
Ion source in use (so I could run the lower pressure)
power 48-53kv, 15-20 ma

You can see the X rays dip -- that means dropping power supply voltage as something outgasses, and then I hit the gas remove solenoid, and they (and neutrons) come back up. I had to let in fresh D a little once, but basically I was running on what's on the tank. Right about 10 min 25 seconds I stopped the fusor (for about 10 min run, since I didn't start it till about 20 seconds into the log), and put the silver on the standard geiger at about 10:35 to watch it decay.
Here's that part of the log file:

0:10:20 CPM1 1560 CPM10 2370 TC 18107 NPM1 1080 NPM10 906 TNC 13899
0:10:21 CPM1 1620 CPM10 2166 TC 18134 NPM1 1140 NPM10 948 TNC 13918
0:10:22 CPM1 1080 CPM10 2022 TC 18152 NPM1 780 NPM10 942 TNC 13931
0:10:23 CPM1 1020 CPM10 1842 TC 18169 NPM1 960 NPM10 936 TNC 13947
0:10:24 CPM1 660 CPM10 1650 TC 18180 NPM1 540 NPM10 888 TNC 13956
0:10:25 CPM1 0 CPM10 1428 TC 18180 NPM1 0 NPM10 804 TNC 13956
0:10:26 CPM1 0 CPM10 1128 TC 18180 NPM1 0 NPM10 702 TNC 13956
0:10:27 CPM1 0 CPM10 936 TC 18180 NPM1 0 NPM10 606 TNC 13956
0:10:28 CPM1 0 CPM10 726 TC 18180 NPM1 0 NPM10 510 TNC 13956
0:10:29 CPM1 0 CPM10 594 TC 18180 NPM1 0 NPM10 450 TNC 13956
0:10:30 CPM1 0 CPM10 438 TC 18180 NPM1 0 NPM10 342 TNC 13956
0:10:31 CPM1 60 CPM10 282 TC 18181 NPM1 0 NPM10 228 TNC 13956
0:10:32 CPM1 0 CPM10 174 TC 18181 NPM1 0 NPM10 150 TNC 13956
0:10:33 CPM1 60 CPM10 78 TC 18182 NPM1 0 NPM10 54 TNC 13956
0:10:34 CPM1 0 CPM10 12 TC 18182 NPM1 0 NPM10 0 TNC 13956
0:10:35 CPM1 840 CPM10 96 TC 18196 NPM1 0 NPM10 0 TNC 13956
0:10:36 CPM1 540 CPM10 150 TC 18205 NPM1 0 NPM10 0 TNC 13956
0:10:37 CPM1 1020 CPM10 252 TC 18222 NPM1 0 NPM10 0 TNC 13956
0:10:38 CPM1 960 CPM10 348 TC 18238 NPM1 0 NPM10 0 TNC 13956
0:10:39 CPM1 1020 CPM10 450 TC 18255 NPM1 0 NPM10 0 TNC 13956
0:10:40 CPM1 720 CPM10 522 TC 18267 NPM1 0 NPM10 0 TNC 13956
0:10:41 CPM1 720 CPM10 588 TC 18279 NPM1 0 NPM10 0 TNC 13956
0:10:42 CPM1 540 CPM10 642 TC 18288 NPM1 0 NPM10 0 TNC 13956
0:10:43 CPM1 600 CPM10 696 TC 18298 NPM1 60 NPM10 6 TNC 13957
0:10:44 CPM1 420 CPM10 738 TC 18305 NPM1 0 NPM10 6 TNC 13957
0:10:45 CPM1 1080 CPM10 762 TC 18323 NPM1 0 NPM10 6 TNC 13957
0:10:46 CPM1 540 CPM10 762 TC 18332 NPM1 0 NPM10 6 TNC 13957
0:10:47 CPM1 660 CPM10 726 TC 18343 NPM1 0 NPM10 6 TNC 13957
0:10:48 CPM1 360 CPM10 666 TC 18349 NPM1 0 NPM10 6 TNC 13957
0:10:49 CPM1 540 CPM10 618 TC 18358 NPM1 0 NPM10 6 TNC 13957
0:10:50 CPM1 300 CPM10 576 TC 18363 NPM1 0 NPM10 6 TNC 13957

(I added some spaces to make the columns line up here, but oops, you edit in proportional font, but display in fixed when you use code tags -- took those out, but now it turns out you get a different non-fixed font for editing, and cannot win with this board software, I had the same set of issues in the perl log display, but could fix them there and did)

You can see a general trend in the neutrons downward. Phosphor fatigue? Phosphorescence buildup that shifted threshold? Or did the neutrons just sag as impurities outgassed from other things in the tank as they got hot? Still more to learn, but this is the tool for that, by gosh. And, with only a little more code and a few more connectors, it could have been logging main volts/ma and tank pressure...maybe we should make that an option for people? All the required hardware, except any signal conditioning and connectors is there already -- the PIC has spare a/d inputs we are not now using, plenty of spare CPU cycles, and so forth.

This is plenty sensitive enough for any working fusor. It won't quite see the neutrons my ion source probably makes (neither do the 3He and B10's), but that's so down in the noise anyway as to not constitute "working fusor", though it looks a little like one, it's just a tiny extra grid way out in the big part of the tank with 15-20kv on it at 10 ma or thereabouts. If it's making neutrons, nothing here sees them with good certainty. It does allow me to run lower pressures and more stable in general, so it's worth having in there -- these numbers are a lot better than the last run earlier today.

And now I have a log file I can study at leisure, open in spreadsheets (if I ever learn those!) and re-plot as soon as I either learn gnuplot's "extensive" command line interface, or write a little perl to invoke it, which is actually simpler for me (don't have to learn yet another language that way).
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.
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Re: Standard counter goes visiting

Postby Doug Coulter » Tue Oct 04, 2011 7:52 am

Though I didn't make it, Bill Fain and Joe Jarski went to this year's HEAS, and used our counter to document some of Richard Hull's fusor runs. Due to how tight things were there, they wound up actually holding the Hornyak up to the fusor by hand to get good numbers, and take some exposure themselves. Some good data was acquired (more of which I'll post when I regenerate the plots from the logs), and a very good cross-lab calibration obtained. Richard's unshielded fusor makes a lot more X rays in the room than mine does, according to this data, which was taken with the geiger portion of the counter a good bit farther away from his fusor than I do here. I'm suspecting some of the variation seen in the X rays (when not counting activated silver) was due to humans being temporarily interposed between the fusor and the counter. We see variations here too, but not so much, and those are usually tracked by neutron output here.
DSC00048.JPG
Bill braving the X rays

DSC00051.JPG
Joe getting a tan

DSC00062.JPG
Results of one run


HEAS was another big success this year, with a lot of other good things happening. I wish I could have made it, but...life happens. More here.

I'll regenerate the plots from the logs they got, and post those too. My takeaway from this is that an optimized fusor has both a certain Q and a certain output given the basic sizes and power.
Watt for watt - Richard's and mine give fairly similar results. I put in perhaps twice the power, and usually at a little higher voltage, and get about 3 times the neutrons. This all makes sense since the cross section for the DD reaction goes up very quickly with energy of the D's, and due to my running lower pressure and higher voltage, I get somewhat less collisions with stopped neutrals, and somewhat less issue with space charge canceling the applied accelerating field. So the differences are not really surprising - what's more surprising is how much the same things are despite our different geometry (his is a sphere), and different power (his is unfiltered, rectified X ray transformer, mine is from a very nice Spellman, filtered and regulated).
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.
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Re: Standard counter now available

Postby Doug Coulter » Thu Aug 23, 2012 6:44 pm

Here's the current code for this, GPL-V2, so if you change it, please contribute your changes back so we all benefit.
SC.zip
GPL code for this project
(620.21 KiB) Downloaded 838 times
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.
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Re: Standard counter now available

Postby Doug Coulter » Wed Feb 19, 2020 12:21 pm

Someone asked for the output format for this, so here it is.
It's a USB serial port, 115200 baud, 8n1, and uses linux line endings (not crlf like windows). Most terminal programs will do the conversion as an option.

Here's a screenshot of some output I just took here.
Screenshot at 2020-02-19 12-07-48.png
Serial output


The first field is uptime, as H:MM:SS
Then the label CPM1 - which is "counts per minute for this sample" - really it's counts this second times 60, since everyone uses CPM but often doesn't want to wait a minute.
The next pair of fields is CPM10 as a label, followed by an average 10 seconds - useful as low level radiation is really random so some smoothing is nice for the human to read.
TC is total counts since powerup. So if you really want to know a long term average, you can use this and the time to compute it.

The next set of fields, which only occur if something has put some input to the BNC connector (TTL-like levels, a low pulse counts - it's not real picky but don't blow in 100's of volts).
They're the same format, but the N means "neutrons" as at the time, that's what we were hooking up to it - some sort of neutron counter. It's able to handle pretty fast counts.
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.
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