Feasability of DIY food monitoring ?
Posted by BC.
What would it take, in terms of equipment, to set up a a DIY food monitoring system? I am thinking a person would need at a minimum a big, pancake style monitor, a laptop, lead bricks to block out background. But how to isolate info on which isotopes are present? Mark posted some cool stuff on how he was able to measure the decays of K-40 in KCl salt substitute, but I don't think that simple set-up could see anything other than the decays (ie, not qualitative).
Is gamma spectrometry beyond the reach of a home-based geek?
Wow, this would be pretty
Wow, this would be pretty awesome if we could accomplish gamma-spectroscopy with a geiger counter!
I looked through some papers and textbooks, but I didn't find any examples of anyone accomplishing this. At the very least a scintillator is required (which is still on the order of thousands of dollars...). I will say this: in theory, a geiger counter can be operated in a way that gives some spectroscopic information, but unfortunately it's extremely poor resolution and will barely be able to detect anything.
You might be able to do some beta-spectroscopy (in the same way that Mark did with the KCl) with the equipment you described. It would be tough, but not impossible! This could still give you some basic isotopic information.
Alternately, you could do some experiments like these, which would give you the half-lives of the isotopes instead of the energy of the gamma-ray. This would be only possible, though, for short lived things like radon and I-131 (unless your very patient!).
Tim [BRAWM Team Member]
Tim- Thank you for your
Tim-
Thank you for your thoughtful reply.
OK, let me flesh this out a little - could a couple of guys with say a $10K budget put together a testing regimen with the type of resolution BRAWM has? I mean, if the resolution is less than say .1 or .2 bq/kg, it will only be good for catching blatant stuff.
I realize that you fellas are plenty smart and have a high degree of education, but I don't think that someone would necessarily need a huge amount of training to put this together. It could be good just for Cs and Sr, no need for others that I can see.
How about it Tim? If you had a $10K budget and 10 hours a week to spend on this, could you put together a small garage lab to do a level of testing similar to what you are doing in the UCBNE lab? Also, what can you tell us about the volume of materials that can be tested? It looks to me like it takes days for each sample to be analayzed.
Again, thanks for your efforts and time.
Hi BC, Let me jump in here.
Hi BC,
Let me jump in here. $10K is actually a nice budget (a bit low) for something like this. In fact, that is about the entry point for high-purity germanium detectors with a 10% relative efficiency (This number is derived from the gamma-ray peak efficiency relative to a 3" cube of sodium-iodide at the Co60 lines @ 1.1 and 1.3 MeV). With a 10% HPGe detector you can do quite a bit of science. However, $10k only gets you the detector, the electronics would consist of a high voltage power supply, linear amplifier/shaper, and a multi-channel analyzer (MCA), along with software (or you can write your own code - not recommended). These are generally NIM-BIN electronics and you may be able to find what you need from EBay or some surplus source for cheap. Normally, this means there is something wrong with the module and one would have to troubleshoot and repair it.
In short, $10k is in the ballpark. Contact Ortec or Canberra and they can quote you based on this budget. Then all you would need is the collection process, lead cave, and liquid nitrogen (very easy to get - Praxair or AirGas).
For that kind of money, you would most likely want to think of a business plan to recoup the expense.
Good luck!
very cool BC. Enterprising
very cool BC. Enterprising and passionate.
Necessity is the mother of
Necessity is the mother of invention, guys! It would be interesting to put together and tweak/play with, then market?