READ ME Anti-Proton.com Geiger counters are an indispensable tool for any scientist, professional or amateur (like me). The Geiger counter can detect radiation quickly and effectively. They are also relatively cheap, ranging from a few hundred to a few thousand dollars (most are under 00). Geiger counters have varying abilities and detect different particles and energy levels of those particles with differing levels of efficiency. By far, beta radiation is detected the best with many tubes detecting 2 to 4 out of ten particles which hit them. Alpha radiation is a bit lower, with many tubes totally blind to them and those which are not only detecting 5 to 10 particles per every 100. Gamma and X-ray radiation is the lowest for Geiger counters, where often between 1 and 3 photons are detected per 100. Pros -- Cheap, easy to use, portable, can detect alpha, beta, gamma, and x-ray. Cons -- Cannot determine isotope (fact), cannot determine energies, very low gamma and x-ray efficiency. Scintillation counters are the tools of the professional nuclear scientist. Scintillation counters exist for gamma, x-ray, beta, and alpha radiation (a specific unit for each). When used with a multi channel spectrum analyzer, the counter can identify isotopes by their energies. Some Gamma spectrometers can even be used for complex gamma recoil analysis (mossbaur spectroscopy) which aid in determining the molecular bonds of various atoms, such as iron. Crystal sicntillators may cost a few ...
Video Rating: 5 / 5
{ 25 comments… read them below or add one }
+/- 20% is still quite optimistic, the analog geiger I have has (well, had, when it was new in 1968
) a base error of +/-20%…if it’s operating outside of 15-25°C, it can have an additional error of +/-30%… All geigers with an analog integrator are going to horribly inaccurate, that’s why they are so cheap…
Quite a shame that we don’t see cheap diode-based detectors, since they are perfomance-comparable with geigers, yet offer the benefits of all-solid-state…
Correct, for sure.
If you DO NOT know the energies you are dealing with, you should use purely counts per period of time (USA: CPM, SI: c/s).
If you know the energy:
Grays are the amount of absorbed energy.
Seiverts are the amount of absorbed energy accounting for the differences in body part and energy time.
It can get VERY complicated and typically approximations are used, such as the energy units on a Geiger counter… not correct, but not massively far off… perhaps +/- 20%
Counts are by no means a way to determine a dose… it depends on the radiation type, the tissue that is irradiated, for how long etc…
The proper unit is Sievert…
The question of safety is a tough one which I am not qualified to answer. It is sort of like asking how much alcohol can you safely drink. I can tell you that I have read loads of papers, discussed this with experts at length, and personally feel safe holding a 37,000 Bq source for a few minutes in my hand each day. But then again, some drink heavy and some drink lightly…
I would doubt that a few hundred CPM on a common Geiger counter would be of much concern, externally… but I am not a doc.
How many counts per minute can people “safely” absorb?
p.s
thank you for you compliment on the geiger counter/ion tube, i cant reply to comments right now.
Wow that might be a tad out of my price range… I’ve never heard of ‘Beejeweled’ and couldn’t find their website, could you link it to me?
Do you know of any other models that might sell between $500 and $1000, the cheapest i’ve found is about $1500. And yes I agree that making my own neutron detector might be the best option.
You can make a neutron detector… I cannot recall how to do so… but I believe it consists of a chemical which absorbed the neutron and quickly decays, they decay being captured.
I hide from neutrons. Nasty little things!!! Have you asked Bionerd23? She might know more about neutrons. (she’s on youtube).
I’m all about the gammas =)
My unit cost me around 4,500, but I have put another 300 to 500 into it. Call it 5,000 USD.
Beejeweled sells an MCA and will even hook you up with a scintillation detector for a quarter of that. I prefer the UCS, which is probably the best of the entry lab-grade units. The next leap is the HPGe detectors, but you need a minimum of 10k for those.
There are spectrometers for all types of particles, nearly. A neutron one isn’t cheap.
Another great video, how much did the UCS30 spectrometer and scintillator cost you from spectech?
Also I am looking into buying a counter that can detect neutron radiation, can the scintillator do that as well or do you know of any other ‘affordable’ devices that can?
Thanks in advance.
AntiP thanks for all your great vids over the last months. I just recieved in the mail a rented ludlum and a big scintillation tube, I want to measure food. I want to make the most of this opportunity, I wonder if you would do me a big favor and email me at radish150 hotmail ? I understand the basics, just need some pointers? If you could that would be great… Thank you.
What is a reliable Geiger counter which can measure dangerous levels up radiation, thus letting me know I should leave?
also, for an extreme example, if I was in the middle of Chernobyl with a Geiger counter that could only measure up to 100 uSv, would it just show 100 uSv measured or would it break, etc. ?
Well, firstly you would scale the readings as you do on a CDV700 (x1, x10, x100) or on a digital unit, which shows a read x 1000.
My unit isn’t really made to be used like a Geigr counter. It is housed in a lead testing container and connects to a multi-channel spectrum anlayser (large metalic box with lights, wires, etc) for processing.
Here is a video of a scint. being used like a GM:
/watch?v=bcbSGoQ7Hg0
Here is one, more like mine:
watch?v=h0dF2FUo5WU
then what is the use of a tube that goes nuts even at normal background radiation?
60 c/s is actually quite normal for a sensitive scintillation counter. A better HPGe detector would get even more.
Light would be a problem, but my unit is quite intact and gets about 4 c/s when in the lead shielding of my detection chamber. Opened to my office, it gets the higher reading.
The scintillator tube is very sensitive to light, so if there is a crack in the aluminum, no matter how small, that would give you very high and false readings. This might be the cause of your 60c/s readings, which I suppose to be false as your other detectors would give the same readings if there was a radiation source nearby.
the same tube that is used in the German Gamma-scout models, a LND 712.
Those are very small tubes, so they can be a little unaccurate.
My CRM100 is weak. I have wondered if it needed some sort of repair. Perhaps I will contact International Medcom today and see what can be done.
It does use an LND 712 tube.
Do you know what tube is in the CRM100 for sure? It seemed awfully weak.
My dog chewed up my Soeks and it works just fine. Goes crazy with some sort of false 32Kreading on CFL bulbs though. Do all those types do that? Paid less than 150 bucks off Ebay for mine brand new. Can’t beat the price
Thanks! I was tired of attending those meetings anyways (joke). I do talk too much, but that’s who it is.
I am about to step outside and measure my water. I might post two videos… one short one showing the facts only (3-5 min) and an epic one, like normal, containing everything^2 (30-45min) =)
I actually have a mild form of Tourette’s syndrome (diagnosed by Johns Hopkins U.). I develop transient ticks. One has always been my speech. =) (actually true)
As for your airplane trip, I don’t doubt you did get such a reading. The radiation from space, quite intense, is attenuated by our atmosphere. As you go up, the air density drops rapidly. After only a few thousand feet you have passed much of the air surrounding the Earth, even though there is much more to go.
Many people have taken GM’s on plane for decades and always, they get high readings (400-800 CPM, or more). Just don’t scare the passengers. =)
Holy shcizznet Tom, you yapayapayap more than my mother-in-law!!! Just show us the equipment, run the comparison and that’s it!!! “It’s easy to talk and hard to show”… you definitely got that one right… you would fit in perfectly chatting with some middle school girls… I could only take five minute of you yapping like a little dog, oh my head!!! You are officially banned from any of my faculty meetings!!!
Geiger counters are useful tools. Typically, the more sensitive the better, but you must also consider cost vs utility. In short, if you are going to run a home lab or something like that, you might want an Inspector or some other “pancake” style model. For the more casual user, the SOEKS sounds fine. My first GM was similar to that unit. I have never used that type, but it looks reasonably rugged and easy to use too.
Sounds like a silly question but what do you think of the little SOEKS device? Cheap but i think it picks up C137.. Also I got 2.5 microseiverts on the plane.
I totally agree with you. The GM is not better or worse than the Scintialltor… it would be like saying a hammer is better/worse than a screw driver.
They are different tools, which sometimes overlap.
My point is that you just don’t use a GM for isotope ID when you have no idea what the isotope is. In your case, a good tick from a lens tell you, 9 out of 10, that you have thorium (you do have quite the collection).
I do love my Inspector EXP+ Geiger counter. =)