Solar Flare/ Radioactive Decay Rate Link

Yours and mine. This is where you can gas on about how you think the universe works. To a point, after that we'll expect you to actually test your stuff and report.

Re: Solar Flare/ Radioactive Decay Rate Link

Postby Doug Coulter » Sun Oct 10, 2010 11:14 am

Sounds like you've got a plan that can work, and of course we'd all like to see pix :) . If it shows you anything, please also make a control version (same but no Am in it) and see if there's something making them both move at once, for control. With the insane cosmic ray bursts we get here, I'd want to be sure it wasn't just that making it move.

For example, I have a 3He proportional tube for neutrons. It normally counts once or twice a minute on background. But on any given day, there will be some 10 second long bursts of many counts (thousands)...this tube doesn't see gammas, alphas...betas (unless they are insane energy).....just neutrons. I have it set so numb that a neutron source of about 1 mrem/12 hours doesn't count it at all -- it will only count if two more more neutrons hit it inside one tube response time (about 20us). We have that on an audio amp, and we thought it was broken the first few times that happened. Then we hooked up some more detectors and found them all going at once on those huge bursts -- all over the shop, so we must have been seeing secondary showers.
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Re: Solar Flare/ Radioactive Decay Rate Link

Postby chrismb » Sun Oct 10, 2010 11:47 am

The other line that this thread might take is to see if we can't brainstorm all the possible 'known' reasons that this might happen.

For example; are there any magnetospheric or low frequency (ELF) type interactions with the Sun that would cause further interactions with Geiger counters? A Geiger counter works by ionisation and conduction, so presumably a magnetic field would affect the way it measures such signal.

Is this effect seen with all types of radiation detector?

Maybe one experiment could be to try placing a magnet at different locations around your device to see if there is a resolvable effect?
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Re: Solar Flare/ Radioactive Decay Rate Link

Postby Doug Coulter » Sun Oct 10, 2010 12:52 pm

Of course a magnet will have an effect on an ion chamber, less on a geiger, but still some. ELF stuff tends to be << one gauss so it's not likely an effect you would see much. Perhaps worth looking at simply because it may itself be a byproduct of whatever causes it, and give something to correlate with. Just a few gauss along the correct axis should shut an ion chamber down more or less, by keeping the electrons confined until they can rejoin the ions. Too bad sensitive magnetometers aren't cheap, but for AC sorts of things, I think Charles made an antenna, and so have I, I built a 5+ hy air core coil to use as an antenna for things like that. Of course for AC kinds of things, the ion chamber walls make a pretty good shield via eddy currents. If it, as supposed by most, is a neutrino effect, well, we are awash in them from the sun (hot) and from all of time (not as hot), so anything that causes them to slosh around might do it -- but we have no clue what would cause that at the moment, else we'd not need the huge detectors we need now for them.

If you could prove it was neutrinos, and then what caused them to do it now, vs another time -- then you'd also have a handle on how to do things with neutrinos we don't have now -- that would be very valuable to have indeed. After all, the only force mankind knows how to diddle right now is EM, that's it. We don't do strong or weak force for example, and I've not seen flying pigs (except as fellow passengers on commercial flights), so no gravity either. To the extent we do anything nuclear, it's more like alchemy than chemistry at this point.

Right now, we need to see the effect at all -- then we need to see it on alpha decays, beta, gamma -- and see if they all do it or just one does. That will give a better clue what it is, for sure.
And that's not going to be an uber-trivial test to make either -- most alpha decayers have daughters that are beta decayers and so on....hard to test in isolation to say the least.
At some point, I think you wind up doing some sort of energy spectroscopy to get another handle on it all.

It's hard to see how neutrinos would affect alpha decay if the models are correct....all that normally should take is something that gets the internal sloshing in a nucleus going better, or less random -- which normally takes megavolt energies, though a little energy might give it a bit of bias. Other types of decay have more to do with things neutrino.

Here's a few scans from Haliday -- Charles, you really want to own a copy of that one (info elsewhere on the board).
AlphaChain.gif
An alpha decay chain


Here's some theory on alpha decay, that still stands up today. There is a huge correlation with half life and alpha energy -- just a little more energy makes the half life a very lot shorter.
(this leaves out some details elsewhere in the book re fine structure)
AlphaTheory.gif
Alpha decay theory as it stands (still)


Here's the ionization produced by an alpha vs distance from the source. As you can see, near the end of their range (lower energy) they do more. This was done with a tiny flat two grid ion chamber moved on a micrometer towards and away from a sample.
AlphaIonization.gif
Alpha ionization vs range curve

AlphaRange.gif
Alpha Range vs energy



As always, click the pix for a readable size view, the board makes thumbnails of anything big. Also, print kinds of stuff is a lot more readable and a lot fewer bits if you threshold it to B&W and make it a gif. Jpg's don't compress text very well. (I use "the gimp" for this)
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Re: Solar Flare/ Radioactive Decay Rate Link

Postby charleswenzel » Sun Oct 10, 2010 10:18 pm

Here's a link to some photos: http://www.techlib.com/newprojects.htm Let me know if you see a problem.

I forgot the desiccant, so I started over today. It will be tomorrow before it's drawing a straight line again. Judging by the plots so far, I think I'll be able to see about 0.05% changes. I'm not motivated to do much more than this, unless something odd happens; it all seems so unlikely! I'm getting a pretty large current, about 100 pA, so I can't imagine background radiation making any difference. I hadn't considered magnetic fields. I hate to open the chamber right now, but that will be worth a look down the road. Well, I do have a pretty big coil that could work from outside the chamber, now that I think about it. First, I'll wait until there's something to explain. I suspect I'm going to get a lot of nice straight lines.
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Re: Solar Flare/ Radioactive Decay Rate Link

Postby Doug Coulter » Mon Oct 11, 2010 8:20 am

It all looks peachy to me, Charles. Now for the dreaded "hurry up and wait" to see if you get other than straight lines, hope your logging system is solid, because there might be some waiting involved here. I would expect a certain amount of long term drifting due to things we've already talked about plus the inevitable slight drift in the circuitry for all the reasons we know.

Obviously the big jump up and down & pop the champagne corks moment is seeing either a large hump or dip superimposed on those straight lines. IIRC the guys who brought this up in the first place were talking about nearly .5% changes, so you should be in real good shape to see that -- the old 10x rule seems satisfied. But all the things suspected to correlate here are slow moving, so some waiting is probably on the menu.


Speaking of ovens, I saw a cool trick using a National Semi heated zener reference as an oven controller (LM 199), wonder if they are still around. This was a to-46 with two heater power leads and two zener leads, usually shipped with a thermal insulator for the can. I saw a trick where this can was soldered to the oven wall, and the heater power draw driving a heater-amplifier scheme ( a power transistor and resistors) also coupled to the heater wall. At the time, they were boosting their LM11 chip which likes it hot, and advising to put them into this oven design. The LM11 itself seems to have gone by the wayside, which is a shame, it was a very nice stable low input current opamp in a class by itself (getting to be that good all bipolar, no fets). I've used those with active input current cancellation/bootstrapping to get EEG data with a pure capacitive pickup -- real high impedances. Maybe there's better stuff now, but at one point that was "it".

LM199.pdf
Lm199 data sheet
(652.87 KiB) Downloaded 334 times


Particularly if the temps were going to get high and get to where that leakage that goes up as square of temp in fets starts to kick in hard.
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Re: Solar Flare/ Radioactive Decay Rate Link

Postby charleswenzel » Mon Oct 11, 2010 11:24 am

I used the LM11 in an oven controller for an oscillator, as it turns out. You're right, that's a nice part. I remember the LM199, but I never had one. I recall the price being an issue.

This data taker is strikingly reliable, considering how it works. It's a bit absurd. For one thing, I receive hum from the surrounding wiring to use as the time reference! (just for the fun of it.) I've had it punching numbers (Keyboard Wedgie style) into a spreadsheet for months without a single issue, beyond my forgetting to start it over at night.
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Re: Solar Flare/ Radioactive Decay Rate Link

Postby Doug Coulter » Mon Oct 11, 2010 1:27 pm

I've used the 60hz for timing a lot, but that's not such a hot move here -- I'm off the grid, and the xtal oscillator that controls that here is outdoors! Fairly stable, but we don't run clocks off it much. Back when I had sq wave inverters, all the stuff that used the line for timing I bought needed to be modified with a better LPF -- my breadmaker thought it was done in under a minute!

I believe National made several versions of those heated references, some cheap, considering the dual use possibilities.

Why do you have to start the wedgie over at night?

Here is what wikipedia knows about decay chains. This is the neptunium one, and the good news is that it takes a loooonnnggg time to make any radon, so this is a good thing to test with.

And here's what wiki knows about amercium, using their book gathering tool.
Americium.pdf
Wiki on Am
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Re: Solar Flare/ Radioactive Decay Rate Link

Postby charleswenzel » Tue Oct 12, 2010 10:29 pm

I'm entering data into a spreadsheet, so it fills up every day. It isn't worth "fixing" since I sit down for a few minutes to observe the day's activity, anyway. Today, the bias supply was acting up, so I replaced it with a little inverter module. I'm still seeing a mysterious barometric pressure effect, albeit much smaller than with the first chamber. I doubly sealed the already-sealed box, so it's a bit of a mystery. If there's a slow leak, I don't think it could track the pressure so quickly. I added a precision thermistor and I may be seeing a slight temperature change in the chamber due to pressure. That would explain the drift, but I don't really know why the measurement is so sensitive to temperature, either. I'm a little suspicious of my 10G resistor. At any rate, I have just compensated the pressure change and the waiting game begins again. I'm going to stop predicting that it's ready to use!
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Re: Solar Flare/ Radioactive Decay Rate Link

Postby Doug Coulter » Wed Oct 13, 2010 11:32 am

Absolutely -- there's enough broken stuff in the world to keep you busy without fixing things that ain't broke.

I wouldn't expect baro pressure to have much effect beyond straight linear and in proportion to absolute pressure, it might be something else if it's bigger than that, or even the same size as the change.
Humidity....can be a big one (very different ionization numbers for water vs air for same energy input). Airtight is a very relative term to anyone who hasn't really done a lot of high vacuum work. Stuff you'd think (and even test) as absolutely airtight appears as giant leaks. And it just doesn't take much. Also, a goodly fraction of an ATM is simply stuck on the chamber walls, to fly off and return variably with heat -- it's an amazingly large proportion of what is there. But also, you can make a chamber, put 120 psi on it, dunk it in water or alcohol, no bubbles at all, but to a vacuum system it's a huge leaker.

I would suspect the R too - been there with those, and the littlest fingerprint can go all weird on you with phase of the moon kinds of things. Since you have so much current, could you not get by with a smaller value, or would your other drifts then be a problem? I see you did the proper air-wiring that gets rid of most of the other error sources. And to those who might think that looked like a sloppy kludge -- Charles is doing it right, a PCB adds an unacceptable amount of variable leakage when working in this regime. Even teflon or quartz give trouble if not CLEAN at a level most don't appreciate. I quote from National's AN241...."Anyone designing high reliability equipment that is going to be in trouble if combined leakages are greater than 10 pA at 125c had best know what he is about." In fact, just thermocouple effects in the solder joints etc will cause significant errors at pretty low delta temperatures, and the low frequency noise from many references can be cut many dB by just potting them, or putting them in a small box to remove fractional degree convection and breezes...as they point out in another app note about testing for low drifts -- it's not a piece of cake to do.

A control chamber/electronics package would help sort out all that, same stuff but no rad source. We do a similar trick with discrete counting things, and use the control output as something to subtract from the active one, once we've convinced ourselves we have "good geometry" that makes that mean something.

If and when I set up one of these (would have to be a solar powered remote so my normal lab antics don't mess it up) I will use something intrinsically more stable, where the measuring media is a scintillator or the gas in a truly airtight geiger counter tube. Counting pulses from one of these has the same effect as a limiter in FM -- removes small noises completely from the measurement. For example, the avalanche effect in the counter gas is such that we don't see any change in sensitivity with temperature, things either do or don't break the threshold. Of course, those things have their own error sources, but IMO are (usually) easier to handle.

But hey, all encouragement :D If this stuff was easy, it would have been done convincingly by someone lesser, a long time ago.
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Re: Solar Flare/ Radioactive Decay Rate Link

Postby chrismb » Wed Oct 13, 2010 2:06 pm

barometric pressure effects on cosmic ray[-induced] neutrons were discussed in this fusor.net thread;

http://www.fusor.net/board/download_thr ... 1243035006

..maybe of interest..
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