This is an idea for an experiment I may or may not do. The background: There have been reported seasonal variations in radioactive decay in the past.
Now If I took a simple tritium light, and a good quality photo-diode, put both in a light proof box, and logged that with a 10 bit PIC ADC with a decent Vref for say a year to FLASH, say 1 sample / hour, run the whole thing of some battery.
10 bits per hour makes 87660 bits per year, or 10950 bytes per year. Have the PIC wake up once every hour to save power.
Would the light intensity from a tritium light be [linear] proportional to the decay of the tritium? And then next year analyze the result (if any)?
Will one year be enough time to see any difference ??
Being an unstable isotope with a half-life of about 12.32 years, tritium loses half its brightness in that period. The more tritium that is initially placed in the tube, the brighter it is to begin with, and the longer its useful life. Tritium exit signs usually come in three brightness levels guaranteed for 10, 15, or 20 year useful life expectancies.[citation needed] The difference between the signs is how much tritium the manufacturer installs.
You'd really have to run it for several years to make sure there's a pattern. And keep the temperature constant, and make sure there are no other seasonal effects. Particle counting would make better data than light measurement.
How about getting a few hundred people to do this worldwide? A USB dongle, maybe.
But the decay-rate variations seen so far happen in a few isotopes, not tritium as far as I know.
Interesting: what does the optical noise look like from a tritium light? It will certainly have shot noise, but are single decays detectable? A betalight and a PMT would tell.
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John Larkin, President Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com
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Unless you are very very careful all you will succeed in measuring is the thermal drift in your opamps and photosensors as they vary with ambient lab temperature. Most of the claims of seasonal variation look like they will fail on variants of this sort of systematic error.
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It is just about possible that half lives of certain nuclear decay reactions could be influenced by variations in neutrino flux, but then you would also expect to see a signal in changed half lives when large pulses of supernova neutrinos transit the Earth as well and not just from the relatively small variation in solar neutrino flux.
Also sling shot launches that have gone very close to the sun do not show any noticeable variation in radiothermal generator output.
Oh that might be fun. Can you get a tritium light in the US? You should get a bunch of phosphor photons for each beta decay. But what's the 'lifetime' of an excited phosphor? If it takes too long for the phosphor to decay that will smear out any spikes.
George H.
hnology.com=A0 jlarkin at highlandtechnology dot com
I ordered a bunch of the key-ring types on ebay, shipped from Hong Kong as I recall. I put a couple on the tops of the bedposts in our cabin, where it's really dark at night, so we wouldn't crash into them in the dark.
You
True.
Light from an old radium clock hand makes beautiful PMT pulses.
I find it interesting that billions are being spent on big-science stuff like CERN, when a little cheap research on possible solar effects on isotope decay could lead to really revolutionary physics.
--
John Larkin, President
Highland Technology, Inc
jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com
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And the illuminated plastic emergency signs for use in aircraft.
In the early days we made a fair number of DIY tritium watches using fishing floats. It had the side effect of making the watch susceptable to a reset by flash gun but apart from that worked well enough.
And quite a good source for a DIY cloud chamber too. The alpha particles and betas give quite different tracks.
The amount being spent on this is about in proportion to the likelihood that it will yield anything really interesting. Various chemical and physical tricks are known to alter half lives of a handful of elements but the claims so far of solar influence on radioactive half lives do not look like much more that systematic noise. See for example:
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If they get a decent signal for a supernova neutrino flash going past then that would be interesting. For the moment it remains a curiosity and they don't seem to be able to make up their mind whether the decay reactions are catalysed by neutrinos or inhibited. The seasonal variation they claim to observe lags the Earths orbital position and is almost exactly correlated with external temperature which I find highly suspicious. YMMV
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Most of what has been written about it to date is from Creation Science kookdom and bears absolutely no relation to reality whatsoever.
On a sunny day (Tue, 20 Mar 2012 08:40:05 -0700) it happened John Larkin wrote in :
Yes several years the same pattern would give more support to any data indicating seasonal changes. But even in one year one should see a cyclic event if it exists.
Cool idea.
Well, at least I can then claim an upper limit.
I taped one to the small Russian PMT I have, and had to lower the PMT voltage to about 100V to get a reasonable low anode current. I can make a stable PMT voltage and amplifier, but the PMT will change, and is very sensitive to even earth magnetic field or any other magnet in the vicinity, plus the whole setup is expensive. A PMT is too sensitive for this, basically.
So today, for lack of a real photo-diode, I took a Nichia green LED, and taped it to the tritium light tube, put it in a box, and made a small test circuit to get some idea of the 'signal' amplitude.
Both in the PMT case and the LED case I scoped the output to, and did not see any 'individual' flashes. There are probably too many activations or the phosphor persistence is too long. I did get speckles last year when I made a movie of the tritium light with the Canon A470 camera:
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The other thing that surprise me, is that even a very strong magnet next to the tritium light does not seem to change the distribution of the light over the tube, or the intensity in any way. All good things for a circuit with a small PIC and photo diode.
---------------------------------------- +5 V | | [ ] 10k [ ] 1k | | || | Chinese multimeter || --- green 2 mA range || \ / \ LED ---------| || --- | | || | |/ | -------------| NPN | Tritium |\/ | light tube | |/ ------| NPN |\/ | ///
2 x BC547B
The resistors are to protect the parts... I get only about 2 uA with this setup, 0 without the tritium light, over range on daylight, so green LED is not what I should use. Will need a good opamp and real photo-diode. Any idea for a sensitive photo diode that does not cost a zillion?
--
John Larkin, President
Highland Technology, Inc
jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com
Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation
IF there is a variation in half-life caused by seasonal changes in radiation ( and its a big IF, IMHO ), then surely it would be easier to detect by gating a strong radiation source on and off locally, and detecting the half-life change in sync. Of course you have to choose the radiation source.... But at least you could reasonably eliminate other external influences, and get a result in a few hours, rather than years.
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Regards,
Adrian Jansen adrianjansen at internode dot on dot net
Note reply address is invalid, convert address above to machine form.
Obviously this experiment is totally hosed. Wormley hints at the problems but as usual he can't understand what's wrong either.
Look. You are starting with a digital source! So why convert to an averaged analog signal to examine the phenomenon? As Uncle Al used to say: Stooopid!
He's the REAL experiment: Start with a radioactive source. ANY you have a reason to study will do. Then using a proper nuclear detector and multichannel analyzer (we all have a couple of those on our workbenches, right? I know I do) to act as a filter for the events we want to see. We set up our conditions whatever we want them to be and start recording radioactive decay events. The data will consist of the number of an event and the exact time it occured (UTC calibrated against proper sources, best with rubidium oscillator. We've all got one of those handy, right? I know I do. They are SO cool!) Then you take data.
If you want you can vary the conditions of the source to see if they have an effect. And then you analyze the data DIGITALLY to try to find anomalies, half-life, rate changes etc. People have done this (no surprise) and small variations seem to have been observed in certain conditions. But they are small enough that they give no decent hints as to what exactly is the mechanism that triggers radioactive decay.
Just to tweak you a bit let's do a thought experiment. Suppose for example you discovered some kind of "ray" that when you shined it on the radioactive source it's decay rate greatly increased and hence its half-life greatly decreased. Think of how cool this would be for getting rid of radioactive waste! You'd have this cave full of vile radioactive waste down there in Alabama (or other useless region) where they store the crap. You bring in the "waste decay ray" and suddenly all that radioactive crap greatly increases it's radiation output. But since it's all deep in a cave anyway, it doesn't matter. And then in a fraction of the time you'd normally have to wait for the waste to be safe, suddenly it's all spent and you can truck in another load to purify. Neat, eh?
All we need is that discovery of the radioactive control ray from you!
Decay is exponential - remember? Half-Life. If half life is a year, then after one hear half has decayed, the next year half of that has decayed, etc so look at it as an RC decay with time constant of a year - and in 5 years (5*tc) it would be essentially completely decayed. So... That sampled light should show that same RC type drop (linear relationship between decay, emission, and light).
BUT!!! There ARE ways to alter (certain) radioactivity. Many experimenters have accidentally stumbled into the way/ways, for over 30 years now. It is only "recently" (Pons and Fleischmann) that some of the methods have been brought to public light. Electronics in the form of fields have been used for ages to enhance nuclear interaction of one form or another,viz: cyclotrons, linear accelerators, magnetic pinch plasma "bottles", torus shaped containers, etc; even inside-out electron tubes. So..the "radioactive control ray" could well be a linear accelerator.
On a sunny day (Wed, 21 Mar 2012 08:23:10 +1000) it happened Adrian Jansen wrote in :
I already tried to find count per minute changes for several radiation sources exposed to anti-neutrinos from the tritium light [2], with the tritium light close and far away (should be third power no?). Within my measurement accuracy, and even over 8 hour runs, using plastic scintillator and PMT setup, I see no clear changes in cpm for radium, thorium, normal background, uranium, and a few others that I am not allowed to mention here. Have not tried kryptonite yet.
Anyways that sucks in many ways, as statistically speaking the uncertainty of my measurements is very high. Sometimes in one run you see a change, and the next one it is not there, How many million times does one has to run to be *sure*?
So I got fed up with that, Einstein once did say: "An idiot is somebody who keeps repeating the same experiment over and over again expecting a different result [1]."
So to let the electronics do the experiment, and look after a year at the data seems a better way to once and for all settle the issue (if solar neutrinos or something else affects radioactive decay). And cheap, all parts are in the junk box.
[1] He obviously never used a MS windows computah. [2] The tritium beta decay, if I am informed correctly, produces an anti-neutrino that leaves the glass tube. Flux wont be very high, so...
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