If uranium is not so radioactive, why does it peg a Geiger counter?
July 1st, 2008
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Well, I’ll answer that for you!
(It turns out my answer was a bit longer and more involved than I initially set out for, but maybe someone will find it interesting.)
You may have seen demonstrations where depleted uranium or natural uranium really lights up a Geiger counter like few other things would, which would seem to indicate that the material is crazy radioactive. Actually, there’s another reason for this, and to understand it you need to understand just how a Geiger counter works.
There are actually many ways of detecting nuclear radiation, including ionization chambers, gas proportional detectors, scintillation detectors and most commonly Geiger-Müller detectors. A true “geiger counter” uses a Geiger-Müller tube detector connected to a rate meter, which displays the radiation detected. Some of these detectors are all-in-one units, where the Geiger tube is mounted inside the unit, but most professional and industrial units have a separate detector probe – allowing for different types of detectors to be connected to the same ratemeter for different applications. If a Geiger-Müller tube is connected then the instrument can be called a Geiger counter, but if another type of detector is hooked up, it would be referred to as a “gas proportional counter” or a “scintillation counter” or whatever the case may be.
The reason Geiger-Müller tubes are most commonly used for general purpose radiation measurement is that they’re simple, inexpensive and generally have pretty good sensitivity, while at the same time not being so sensitive that they are flooded by background radiation. The Geiger-Müller detector is pretty simple in principle. It consists of a tube which is filled with a gas or mixture of gases. The tube has an anode and cathode, although the cathode is often the outside of a metal tube. By convention, the anode is on the inside and the cathode is grounded. Voltage is applied, but the circuit is normally open. However, when a charged particle, such as an alpha or beta particle, or a gamma ray photon enters the tube, it may cause the ionization of a gas atom. The electric field created by the voltage applied to the tube makes this ion accelerate toward the electrode of the opposite polarity. In the process, it collides with other atoms and creates more ions.
This avalanche of ionization happens in a fraction of a second, and when it does the gas becomes far more conductive, allowing a spark to jump between the electrodes. This closes the circuit and creates a pulse that the rate meter registers. In many cases it also has a speaker on it which produces the characteristic “click click click” of the detector, with each click representing an ionization event. Shortly after the spark closes the circuit, the tube is “quenched” by either a “self-quenching” gas mixture or by the meter monetarily reducing voltage. Quenching returns the gas to a non-ionized state, thus opening the circuit so that another event can be detected.
One thing that is important to note is that a Geiger tube will not detect all of the ionizing radiation present. Most tubes will detect gamma and high energy beta radiation easily, but alpha radiation is more difficult to detect as it is less penetrating. Thus tubes sensitive to alpha radiation are made with a very thin “window” made of a material like mica, which alpha radiation can penetrate. Even so, many of the alpha particles will collide with the atoms of the tube’s window and never make it in to be detected. Gamma radiation is more penetrating, but some gamma ray photons will be blocked by the material of the tube. Additionally, a large portion of gamma ray photons may go right through the tube without ever striking an atom. This is not uncommon, since the gas has such a low density that there is a large amount of space between the atoms for a photon to pass. If a gamma photon passes through the tube without ever ionizing the gas, it also will not be detected.
This might sound like a problem, but for many applications, just counting a portion of the radiation is preferable. For example, I have a scintillation detector which has a high density plastic detector material. When hooked up to a ratemeter with audio, the sounds of clicks are not discernible – instead it sounds like radio static as it is flooded by the background from geological sources, cosmic rays and other such background. This would make such a sensitive detector difficult to use for quick surveys and other similar activities, as the audio is all but useless and the meter may not move as quickly to show the difference in radiation at such high count levels. Thus, a geiger tube may only count 10% of the photons which pass through it, but that’s generally plenty for basic surveying and safety measurements.
But there’s another problem: not all photons have the same probability of being detected. Gamma rays come at different “energy levels” which are the equivalent of wave lengths or frequencies. Higher energy gamma rays have a smaller wave length and thus they have a much higher probability of passing through a material (such as the gas in a detector tube) without ever striking an atom and causing ionization. The lower the energy level of a photon the more likely it is to cause the ionization, but only to a certain point, because bellow a certain point, the photon will have a higher chance of being blocked by the outer wall of the tube and never even making it in. Thus, a geiger tube has different sensitivity to different energy levels of gamma photon.
As a consequence of this, the response of a Geiger-Müller detector can vary widely depending on the energy level of the gamma rays being measured. A given tube may have an average response of 5% overall, but the actual response to varying energy levels may range from less than 3% to more than 20%. The image to the right is from the Health Physics Society. It represents the response for a given thin-walled tube to a varying spectrum of gamma photons perpendicular to the tube’s window. This graph is quite typical of most Geiger-Müller tubes, which tend to be most sensitive to energy levels of around 50 keV to 100 keV. Some tubes may have an even more dramatic peak of sensitivity.
Having high sensitivity to lower energy gammas might seem like a good thing, but the standard for calibration of Geiger counters is normally cesium-137, which (by way of the daughter product Ba-137m) produces photons with an energy of 662 keV and many other radioactive substances have emissions which are much higher. Therefore, although the detector may have a certain response for most high energy ranges, at lower ranges the response will be much higher. Since a Geiger-Müller tube can’t measure the energy range of the gamma rays, it’s difficult to tell the difference between a relatively small amount of a lower energy emitter.
To address this, some tubes have a special filter material in them which is designed to block more of the lower energy photons and thereby provide a response that is less lopsided. These are known as “energy compensated” detectors. The image to the left is also from the Health Physics Society and shows the response for a detector similar to the one above, but with energy compensation built into the tube. This tube has a much more uniform response for most energy levels and does not have the enormous peak in sensitivity seen above. Still, the response is far from uniform.
What all this has to do with uranium:
Most Geiger-Müller tubes are not energy compensated and thus will have a higher response to certain gamma energy ranges, and it turns out that uranium-238 and its daughter isotopes just so happen to produce a lot of gamma emissions which have an energy level which is right within the most sensitive energy range of most detectors. I found this webpage which showed the energy spectrum for Fiestaware brand ceramics with a uranium based glaze. Here’s the graphic from it, credit given to the original author (this seems like it would be fair use so hopefully I won’t get sued):
Now notice where the highest peaks are. The majority of the gamma emissions are around 100 keV or less. This is exactly the region that many detectors are the most sensitive to. The only major difference between natural and depleted uranium is the peak associated with U-235. One of the biggest emitters if Thorium-234, which is a decay product of uranium-238 and is present in any sample.
So if a Geiger counter comes with a test source which contains something like cesium-137, it will register dramatically less counts from the test sample than a uranium sample of equal activity. Thus it would be easy to conclude that a low energy gamma source is the same activity as a high energy source that is actually as much as twenty times higher in activity!
The readout on meters:
Most Geiger counter/rate meters have a readout that is in counts per minute or counts per second. This represents the average number of gamma rays or charged particles detected in a minute (or second). However, many meters also have a scale in r/hr, for “röntgen per hour,” a measure of total ionization dose. It may also have “REM per hour,” a human-adjusted dose rate or “Sieverts per hour” – a newer SI derived unit which measures the same thing.
But if you know anything about radiation dose, you may notice something a bit off here. A Geiger counter can’t tell the difference between alpha, beta and gamma radiation and it certainly can’t measure the difference in energy levels, all of which would make a big difference when it comes to dose rate. Furthermore, the actual response of a Geiger counter varies, so the readout doesn’t tell you the total radiation, if you don’t know the material you’re dealing with.
So how does it know the dose rate? If you look at the meter you’d think there is a fixed ratio of dose rate to counts, which there isn’t!
Actually, it doesn’t know. The readout on a Geiger counter is not necessarily an acurate measure of the dose rate. Rather, it’s an approximation of the dose rate for a given count level of a standardized isotope. Normally, cesium-137 is used, but if the instruments is really really old, it may use Ra-226 as the reference material. In reality, when measuring a combination of particle and gamma radiation or materials with a much different energy level than Cs-137, the dose rate is basically meaningless. And, since the ratio is fixed, it only applies to a given probe that the unit is calibrated to. If you swap it out for a more or less sensitive probe than the meter movement was meant for, the number is meaningless.
So why do they put it there?
Well, it’s a decent approximation of total dose rate for certain circumstances. Cesium-137 is the largest gamma source in old spent nuclear fuel or fallout and many isotopes of concern are within the same approximate energy range. For survival in a fallout situation or dealing with man made radio isotopes, it’s a good enough approximation to get some basic safety information from and to compare data between different meters with different detectors.
Conclusion:
Geiger-Müller tubes are a great way of measuring ionizing radiation for general purpose survey work. They’re simple, inexpensive and have good sensitivity for most work. They come in numerous sizes and styles and can be used to detect both particle and gamma radiation. For finding a source, checking for leaks or getting a rough measurement, they’re often the way to go.
However, for gathering more conclusive data for scientific purposes or to assure accurate measurement, they’re a bit limited. A gas proportional detector can provide better data, distinguishing between alpha, beta and gamma radiation and allowing for measurement of the energy level of gammas, thus giving a more accurate overall radiation level. To get the full picture it can be connected to a multichannel analyzer to determine the energy level spectrum. This allows for both a better measure of the radiation levels and it makes it possible to identify the materials possible. One disadvantage of a gas proportional detector, however, is that many require a constant supply of counting gas circulated through the detector, making for a more complex and bulky setup.
Another alternative is a scintillation detector. Most scintillation detectors can only respond to gamma or beta and gamma radiation, but alpha-only scintillation detectors exist as well. These detectors can be extremely sensitive, sometimes too much so for measuring sources up close. They also allow for spectroscopy by hooking them up to a multi channel analyzer.
The gold standard, however, are solid state detectors like germanium detectors. They give the most accurate energy spectrum measurement, but they need to be kept very cold to function properly. In most cases this means a big tank of liquid nitrogen, although some units are actually portable and contain a small refrigeration unit right within the instrument. Unfortunately, these ones are new and expensive, so you probably won’t be able to play with one, unless you’re Larry G.
This entry was posted on Tuesday, July 1st, 2008 at 10:30 pm and is filed under Bad Science, Depleted Cranium, Good Science, Misc, Nuclear. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
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July 1st, 2008 at 11:26 pm
Good over view, and a good post
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July 2nd, 2008 at 1:03 am
Well most of that stuff admittedly is beyond my level, but its pretty well explained and I think it should put the whole thing to rest or at least explain the issue if anyone should care to find out.
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July 2nd, 2008 at 1:28 am
Really an excellent primer on geiger tubes. I would love to see some more of this kind of writing maybe on other instruments. That’s just a suggestion. It’s very straight forward and easy to understand. Hopefully those who could use a better understanding will read something like this.
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July 2nd, 2008 at 2:13 am
This is probably a really dumb question, but where do they draw the line between gamma rays and x-rays? I am assuming that these detectors can detect X-rays as well, but is there really a difference? That confuses me.
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July 2nd, 2008 at 10:44 am
I still don’t know how the hell you know all of this, DrB. I know “reading” and everything, but still, it’s a pretty detailed description of something I’d consider specialized and obscure which there are others of here too. It was an interesting read though. It does explain much about how you could be deceptive about how something like uranium looks more radioactive than it is compared to other thing.
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July 2nd, 2008 at 11:02 am
Who is “Larry G” and why does he get to play with the new/expensive radiation equipment?
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July 2nd, 2008 at 12:11 pm
Damn, that was a good education. As an engineer and tech, I always knew that an instrument is only as good as the user’s ability to read and interpret the output, but this really opened my eyes about how easy it is to fool the general public.
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July 2nd, 2008 at 12:50 pm
[Applause].
Very informative and a great introduction to the subtleties of these instruments. Radiation is feared out of all proportion to its threat, partly because there’s so little understanding or simple explanation around.
One immediate effect of the data on uranium combined with Geiger sensitivity is that depleted uranium might appear just as radioactive as natural uranium (on the basis of detected counts) because the U238 and Th234 register so strongly.
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July 2nd, 2008 at 1:28 pm
Castle Bravo said:
Larry G is a very accomplished and knowledgeable health physicist who occasionally graces this page with his presence and leaves some excellent and informative comments.
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July 2nd, 2008 at 1:59 pm
Peter Piper 13 said:
It’s a really good question, and one that I also wondered about for awhile. There are low energy gamma rays that are less energetic than very high energy X-rays, so what’s the difference? It’s obviously not a frequency/wavelength cutoff…
It’s this: gamma rays come from the nucleus. X-rays come from transitions in the electron shell. No X-rays come from the nucleus, and no gamma rays come from electron transitions. That’s it.
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July 2nd, 2008 at 2:59 pm
If that is the case, then they’re basically the same I assume, I mean if you detect something and you don’t know what the source was then it’s basically the same? I’m just thinking that it sounds more like a definition kind of thing because it’s the origin of where it came from and otherwise once they are out they’re the same, I guess?
Interesting.
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July 2nd, 2008 at 3:55 pm
Peter Piper 13 said:
Am I the only one that doesn’t have a clue what this commenter is saying?
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July 2nd, 2008 at 4:43 pm
DV82XL:
He’s talking about gamma rays vs. x-rays. See comments #4 and #10 (another argument for threaded forums…).
And Peter Piper 13, if all you have is a detector that gives you the photons’ energy, AFAIK, yes. Gamma rays are “harder” in general, but there is a gray area.
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July 2nd, 2008 at 4:46 pm
Think I know what he’s saying – that they’re defined by their point of origin rather than their actual properties (or as well as them), unlike other forms of radiation.
If anyone doesn’t know what I’m saying, it’s probably because I’ve had a few pints.
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July 2nd, 2008 at 5:10 pm
I found it extremely interesting, thank you.
I’ve been pondering buying a hobby Geiger counter, but have never been entirely satisfied as to how useful it is (or what I’d actually do with it).
http://www.geigercounters.com/Radalert.htm
I mean, even if I have a hypothetical nice piece of equipment that can detect every single kind of radiation, tell me what it is and how intense it is, what exactly am I going to do with it?
-an armchair nuclear enthusiast whose family thinks she’s a little off
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July 2nd, 2008 at 5:32 pm
An excellent rundown and basic information! However, one thing that I’d like to add: The way the display of r/hr on a counter is stated makes it sound like it’s useless and just a guess. This is not entirely true, because yes a Geiger counter does not detect all radiation energy levels equally, but these energy levels also matter as to what the dose is, since higher energy is more likely to go through tissue without any ionization.
It’s still not that accurate though. I believe a good, well calibrated counter should be accurate to +/- 20%, possibly 30% in more extreme situations where the energy levels are very skewed. You’re right that is nowhere near good enough to do measurements for any hard scientific use where accuracy is important, but it is enough for basic safety and dosimetry use.
One other thing is that the r/hr only applies to background radiation and not to measurements of a given source, especially if the detector is capable of picking up beta or alpha radiation. In cases where the probe is right up against the source, the reading is meaningless – even more so if the source emits a large amount of particle radiation, so if that is the case, you would want to step back enough from it to get a more acurate reading of the proximity radiation.
It would only mater for the general ambient numbers, and it’s less than ideal. There are some ionization chambers which do a very good job and giving the overall dose, but they’re too slow in response for any surveying. As is also mentioned, the ratio of r/hr to CPM is entirely dependent on the probe as well, so if you have a meter that has a display of CPM and R/hr then that’s only for a given model of probe and if you use a different one or swap them, then the r/hr is meaningless again.
One thing I’ve found annoying is that if you don’t know which meter movement a ratemeter has on it you don’t know if the r/hr is meaningful or not. You can swap out the meter movement, but that’s expensive and more work. Calibrate them in CPM at least avoids this, but that should be labeled on the unit. If you have a disorganized storage room, well, that leads to some issues.
There are some nice digital meters though, where you can have multiple displays on an LCD for different probes. They’re nice.
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July 2nd, 2008 at 11:34 pm
Space Cowgirl said:
Actually, there’s quite a few fun/interesting/educational things you can do. You can find or collect various antiques or other consumer radioactive items. You can hunt for them in antique stores or hunt for radioactive minerals or rocks – or you might even find something strange like an orphaned source that is in a piece of scrap metal. You can also demonstrate that bananas and Brazil nuts are considerably more radioactive than background. You can demonstrate this or show shielding.
I actually sell Geiger counters, both some handheld units which are quite inexpensive from Russia. They’re simple and only sensitive to gamma and high energy beta radiation but they’re very simple to use and fit in your pocket and they’re only $80. Decent for hobby stuff or I like to keep one as a spare in my car or something.
I also have some that are the more pro-grade stuff. I have a number of Ludlum Model 2’s. Here’s the ludlum model three: http://www.ludlums.com/product/m3.htm
It’s identical except it has one more range setting – pretty minor addition and not usually that important. The model 2 preceded it and was discontinued a few years ago for the model 3. If you want one on a budget I’d sell one on the low end for $120 for one that is in perfect working condition but with some bad scuffs in the paint and with one or two of the stickers missing on it. Also, it had some corrosion on the battery terminals which I cleaned off, but still it stained the battery container a little bit. That is all cosmetic though. However, it would go up to $300 for one that is in near mint condition – perfect working and very little cosmetic damage.
That’s just for the meter though. The probe will be an even larger range. I have a very and big sensitive scintillation detector which is near and dear to my heart so that would cost… well… geez, I really don’t even want to sell it, but I would for $325. I have some good pancake probes that I normally sell for $100 and I have some end window ones for $75. Also, I have some cheap side-window ones. Those… well, $20 I’d say… maybe I’d throw one in if you sweet talk me enough.
I have some others as well. A few Eberline and one Johnson Nuclear. I have a Dosimeter brand digital meter with integrated scaler and logging. That I’d have to check the market price on before hand.
Then I have some other specialized stuff. An NAI scintillator, some adapters, two alarm ratemeters, a semi-portable multichannel analyzer, an SCA addon. Also a couple mylar ion chambers and personal dosimeters.
You know I really ought to inventory and price this stuff. I’ve neglected to for a while. It’s hard to do a “fixed price” on this stuff because a lot of it I’ve gotten in is unique or I’ve only had one of them. Also, the condition varies widely. They all work well, but some of them the knob doesn’t turn quite as smoothly as it should or there is cosmetic damage. Ludlum meters are built like a tank, so they work very well most of the time.
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July 3rd, 2008 at 2:26 am
I understand what you are saying about it all being odd lots, but if you put up a page with some information I might be interested. If I could get a decent setup for $150 that I could maybe upgrade with different probes in the near future, I’d be interested!
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July 3rd, 2008 at 2:41 am
Check your email. I’m very interested in possibly doing some business with you. You’re right about the Ludlum meters, they are very solid and good quality equipment and well built. Definately pro grade. They tend to be pricey too. I’d be very interested in what probes you might have as well, especially if you have any pancake probes.
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July 3rd, 2008 at 3:30 am
I understand what you’re saying event hough I admit that I skimmed over a lot of that, but I’m not sure what that has to do with depleted uranium. I’ve heard a lot about how the dust is really dangerous and increases cancer and birth defects and is causing a lot of problems in soldiers. So what if it overregisters? It’s still very dangerous stuff. I personally support the efforts in Afgahnistan but I’m split on Iraq even though I think the first gulf war was necessary.
But even if I support them, I don’t think we should be using depleted uranium. I’ve heard a lot about how it’s nearly impossible to clean up even on ranges where it has been used in the usa. They probably should just bury it deep underground like they do with most nuke waste either that or figure something else out but it’s so bad for the health of people it should not be used in bullets or anything. Too many soldiers with cancer or other diseases it seems.
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July 3rd, 2008 at 4:19 am
Void Main said:
You have been misled by the anti-nuclear movement, but be glad! You have come to one of the best sites on the net for purveying factual information concerning such topics.
You may wish to check out this post:
http://depletedcranium.com/?p=453
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July 3rd, 2008 at 10:52 am
Interesting, I never knew this.
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July 4th, 2008 at 1:51 am
Finrod said:
This website sucks. It’s all pro-war, pro-bush, pro-pollution and I’m not surprised it would be all for something as horrible as depleted uranium on civilians! This is out time’s holocaust!
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July 4th, 2008 at 2:12 am
Nathan said:
I don’t see how this website is pro-war. I don’t think there was ever any talk condoning harming civillians in any way. There has been some general discussion about the facts of uranium toxicity and of the inflated claims of harm to populations. I thought the Iraq war was pointless and I still do. However I agree 100% that making up claims of DU poisoning is exploiting the suffering of others and it’s unnecessarily scaring military families and veterans as well as people who live in those wartorn areas.
The idea that it’s okay to use photos of kids with horrible birth defects, which were likely caused by poor nutrition and prenatal care and put them next to a made up claim is offensive to me. When I think that a genuine health care crisis could be obscured by a fancy PR-campaign behind a made up story or that people want money going to deal with a non-existent issue when there are people being hurt in these areas by other things and poverty in general that disgusts me, I’ll admit.
Does that all make me pro-war? Just tell me. What is so pro-war about that?
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July 4th, 2008 at 3:23 pm
Gordon, “pro-war” means anything he doesn’t like or disagrees with. Liberals are raised to believe that everything is connected, so it is not at all a big step to tie everything you disagree with together, then take the names describing those things and make them all synonyms for each other. So if you’re against abortion or socialized medicine, or in favor of nuclear power or loosening regulations on business (to take a few prominent examples of positions that liberals are not allowed to take), you’re pro-war, whether you actually support war or not.
This explains exchanges such as:
LIBERAL: Why do you support nuclear power?
YOU: [Long technical argument]
LIBERAL: I don’t care about your rationalizations. You want to oppress women, rob the poor, and destroy the environment. I bet you’re drunk, too. People like you is why we got into Iraq and you want to keep us there for 100 years. Where’s your NRA card, nazi? All you rich boys riding around in your BMWs playing golf with all your Enron friends–you got your cake and you’re eating it too, all the way to the bank, like Marie Antoinette said! And now you want mine! Well, you’re not getting it! Can I have a picture so I can photoshop you into Klan robes? [Conclusion: Philippe Petain wore pink satin pants.]
Believe me. I was one of those people once. Then I tried to get involved in liberal causes, and realized that they were for the most part utter loonballs and they don’t want anyone who will question what you’re supposed to believe. If you have qualms about something, you’re expected to keep it to yourself for the sake of group cohesion–because, after all, defeating the Indeterminate Amorphous ‘They’ is the most important thing in the world. I honestly tried to bury my differences and get on with the task and be a good socialist (Equality for everybody? Who could disagree with that? Put aside your differences and join the people who are trying to accomplish it!), but I couldn’t–I would raise objections, saying that a given action would produce a given (to me) unquestionably bad result, and they would say, smiling from ear to ear and nodding vigorously, “yeah, yeah, exactly,” while I sat with my jaw dropped. Eventually I got the hint, deduced that I didn’t really share any goals with those folks, and left.
Most people don’t. Look at the “10 things” thread and see how many people told Steve that the post was nice and brought up some good points, but was confusing some people and should be taken down. That’s what they were saying–if you’re a real environmentalist, a real liberal, you’ll put away those little misgivings of yours and leave it to the people who really care about the environment. After all, since we’re environmentalists and we’re in favor of the things you’re wondering about, you can be sure that we’ve thought it over and since we’re on your side, the “good guys” as it were, our reasoning is as sound as yours would be, so don’t worry about it. Groupthink writ large.
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July 5th, 2008 at 2:07 am
The ten things thread took on a life of its own. But yeah, I was totally surprised about the “We appreciate this but…. you absolutely must take it down… take it from us… it’s important and if you’re a good person you’ll do it”
Actually, I’m not one who considers myself a ‘conservative’ and I’m sure as hell not a ‘liberal’ – I’d prefer to do things on an issue-by-issue kind of way, but I guess you could say I’m more libertarian than anything else. But I’m not a purist there either, because although I think the government doesn’t do a good job at many things, I support government administration of certain things that are in the national interest – many of which a true ‘libertarian’ would likely become sick at the very thought of.
It’s amazing how many times this page has been called “left wing” or “right wing” – Uh… I’m pro-business but also I generally think social freedom and equality regardless of background or preferred place in society or lifestyle is a good thing. Also, I don’t like business that doesn’t play by the rules. uh.. so what is that?
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July 5th, 2008 at 8:19 am
drbuzz0 said:
An objective rationalist. A good indication is that you manage to piss-off all sides of the doctrinaire divide.
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September 6th, 2010 at 6:52 pm
While I saw an immediate response to ‘Nathan’ s post by Gordon … I now find his Gordon’s response disingenuous and tainted by the fact that he did not respond to Stewart Paterson ultra Fox / News Corp / Clear Channel talk radio Conservative reply. So much for fair & balanced. ( oh wait they had to drop that when they discovered that News Corp. / Fox major partner Prince Al-Waleed is funding the New York Mosque ).
There is no such thing as a Liberal or Conservative. People are just dumb people with a wide mixture of beliefs & opinions. There is manipulation from all sides by all large media corporations brainwashing you into sides so others can ‘divide and conquer’. Better drop that Crap right now – cause if your a Real American its “United We Stand” and if you can’t take the good with the bad or the differences of opinion you don’t belong.
So some guy posts a rehash of known info about old out of date Geiger Counters. What exactly does that prove? And if the tech in the top photo is checking only for a certain radiation that a Geiger is well adapted for then great. Is anyone here seriously suggesting that the scientists checking for Depleted Uranium don’t know what test equipment to bring ?? Is anyone here actually suggesting that you can trust the U.S. Military to tell the truth ??????? Really. Are you children? Tell you what – I’ll give you $2000 for my own amusement if you let me purchase some left over tactical gear or a spent shell brought home by one of our own and all you have to do is place it under your favorite cushion where you watch the brainwashing machine …er.. i mean -T.V and leave it there for one week. Lot’s of ‘Talkers’ here … any ‘Takers’??
Regarding those who are afraid of PHONY terrorists, Ben Franklin has a message for you cowards: “Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.” WE ARE going to build that mosque but not because America has a strong spine with regards to liberty ( you do know that we are not at war with Islam or Muslims & that many, many Muslim Americans perished in the Twin Tower collapse ? ). We ARE going to allow it to be built because between our new ‘owners’ the Saudis & the Chinese, the Saudis want it there and there is NOTHING you can do about it. Why? Because you believed all this corn pone Political nonsense & ‘terrorism’ bull and were sold out – YOU took money you can never pay back – that means that your now literally OWNED. The wars are looking a lot more expensive now aren’t they… enjoying that fried baloney sandwich ?? Enjoying the Re-Depression ( that has yet to actually begin !) Here redneck have another helping of Freedumb Fries. Oh and better shut up and just take BP’s money cause they cleaned everything up better than before right. Right.
And watch out for those liberals … if you let them loose they start doing things like, joining in Civil Rights Marches, Filing petitions and cases that go all the way to the Supreme Court regarding freedom of speech, Voting for equal pay and equal rights, educating & demonstrating about poisons in our food & environment, freedom to petition the government when it’s being thwarted, protecting wildlife because just because species do go extinct there’s no reason it has to happen because a few people want to get rich and build condos, Exposing voting machine fraud, you know all those ‘Looney’ things the list goes on and on.
Oh, ..wait … I forgot, how embarrassing – The ‘Rapture’ is coming so it all doesn’t matter. My bad.
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September 6th, 2010 at 8:03 pm
Unfortunately when you are as poorly educated, and too lazy, or too stupid to learn the basics, like Jason here, you are left only with inductive reasoning based on ignorance and prejudice to make sense of the world around you. Thus, for example, anything that the U.S. Military says must be a lie, and anything a the majority of experts state must be tainted by corporate interests. In his world only the lone dissenter has any creditability, even if said dissenter has no qualifications, (and is making a living telling his story) because that is how Jason et. al. sees himself.
As for DU, I will be glad to take up Jason’s offer and put a chunk under my seat. The thing is I know that this will do nothing to me if I left it there forever. This is because I understand the fundamentals and thus I don’t have to depend on paranoia.
The rest of his post is mindless ranting, and beneath notice.
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September 6th, 2010 at 10:21 pm
In that long rambling and generally completely irrelevant statement, this is the only part that would seem to directly deal with this post.
Jason said:
First of all, Geiger counters are not old or out of date. Despite their limitations, the Geiger-Muller tube is still the most simple, cheap, rugged, reliable way of detecting ionizing radiation.
However, you have to understand the instrument to really know what it’s telling you.
In general it’s not “scientists” who are using and misusing equipment to show the effects of uranium. It’s people who will go out with a Geiger counter and wave it around and say “Look how much it’s clicking! Look at the meter” and then use that to claim uranium must be super-radioactive.
First of all, a Geiger counter can detect levels of radioactivity far below what is actually dangerous.
There’s something else you have to understand – uranium, by its very nature is over-represented on most Geiger counters. Most of the emissions from uranium are from 50 to 100 KeV. This is considered very “Low energy” or “soft” gamma emissions. This is also the area Geiger tubes tend to be most efficient in detecting.
An average Geiger tube may register close to 20% of photons that pass through it with an energy of 100 KeV but will only register 2-3% of photons of 400 KeV. That’s a big difference! It also means you can’t use the simple R/hr shown on the dial as a meaningful number for low energy sources.
Why is this important? Because this over-sensitivity can make it seem like uraium is more radioactive, relatively speaking, than it actually is – IF you don’t really know what you’re doing or are showing it to an audience who does not understand. In fact, uranium is only mildy radioactive. But, if you get up close to it, you can still peg a meter.
Jason said:
Are you serious? I would suppose you are probably not. However, if you are, please let me know. I could use two thousand dollars.
I have some depleted uranium – not much – about 50 grams of the stuff. Right now it’s in a jar not more then four feet away from me. That is where it sits most of the time when I’m at my desk, which is where I spend a considerable amount of time. If you prefer, I’ll stick it under my chair for a week. If that’s not enough, I’m sure I can manage to get more than 50 grams.
Seriously, I’ll absolutely take your offer.
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September 7th, 2010 at 12:05 am
Jason said:
I’m in. A couple thousand bucks would be pretty useful.
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September 7th, 2010 at 12:06 am
Matthew said:
Also, would I get to keep the DU? I could use a paperweight.
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June 19th, 2011 at 3:23 pm
If you need good radiation than visit this store: http://www.soeks.co.uk
Soeks geiger counter is very good and chip!
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January 20th, 2012 at 12:48 am
NSDU-238 stands, equitably for “not-so-depleted uranium-238″ which is 60% fissile. Yet, this is not exact because the munitions comprise 4-5-6 radionuclides,and are also of varying isotopic-Discrepancy. How is there a possibility of a gdigital-Meter for measuring these “on site” and what investment levels>
As there are many examples of “illegal-usages of NSDU-238″ in Iraq, in Bosnia-Hercegovina, in Kosovo and in Yugoslavia, as well as in Libya, what coercion can be deduced for needs of “defensive-Protecting” of civilian populations, since these usages, and civilian-Exposures and deaths?
There was also usage of uranium-Bombs, some tipped w DU heavy-Metal use in Afghanistan in 2001; Libya last year, Yugoslavia in the 79-Days bombings, 1999. What the radio-isotopes range on those differing geography entails is in need of “assaying by measuring” and the solicitation is how would humanity be to be able to encompass actual rasty use for that radioisotopic-Amount.
What kind of digital-Meter would that be? What kind of metering are those available, as all “uranium”is radiation?
Seems to me the more that radionuclides are measured, the better chances in defining what is over-Contaminated. However, this is not an easy task, and means better garments and much better micron-Pores sized masks. What of eyes that water? There is not yet a set-pattern, about measuring which should be useful for the aging N{{S starting in 2000. UNless manufacturers are quasi solicitous in holding back their own degeneracy! You may want to see what ilk-Rebukes one can amalgamate into why not-so-depleted uranoum should be considered “radilogic-Uranium: first” @ http://nukiemole.org
“R” Addison, the peace-Warrior
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January 20th, 2012 at 1:49 am
“R” Addison said:
I’m not so sure what you mean by “not so depleted uranium.” Depleted uranium has had most of the U-235 separated out. The natural concentration of U-235 is about .3%. In depleted uranium it is usually no more than .1% and most often it is much less. The amount present is dictated by the economics of further separation.
There would never be 60% fissile material. That would qualify as “highly enriched” and, if nothing else, it’s very expensive. All I can think is you’re saying that perhaps 60% of the uranium-235 naturally there is still present? I guess that’s possible, although it’s usually less than that.
Any U-235 present doesn’t really matter though. It has a minimal effect on the radiological characteristics since it’s such a tiny proportion. Depleted uranium is only slightly less radioactive than natural uranium.
“R” Addison said:
Uh… what?
“R” Addison said:
Probably an inexpensive geiger-muller detector. That works fine for simple surveying. It will detect elevated concentrations of uranium.
It depends on what you are trying to determine. Different instruments tell you different things. If you want to know the quantity of uranium present, that’s a little tricky, because it depends on how it is distributed. Some of the emissions can be shielded. I don’t think simple surveying is a reliable method of determining how much is present, actually. For that you would probably need to take some soil samples for analysis.
“R” Addison said:
Uh… well, the meters in this case don’t actually tell you what radionuclide is there. A geiger counter can’t tell the difference between uranium and anything else. For that you need some kind of spectrometer that can measure the characteristic energy levels and then compare them to a database of isotopes. There are ones that are portable but they’re expensive.
“R” Addison said:
Wait… what?
“R” Addison said:
Wipe them with a tissue and avoid chopping onions.
“R” Addison said:
uh… wait.. what? You lost me
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January 20th, 2012 at 2:29 am
drbuzz0 said:
I thought natural Uranium had 0.7% ²³⁵U and that depleted was typically around 0.3% or 0.4%.
“R” Addison said:
drbuzz0 said:
From what I can tell that idiot was advertising its web site and thinking that opposing a single weapon used in very limited circumstances and which doesn’t cause much collateral damage is actually going to significantly help the cause of peace (all that opposition to DU could realistically do is cause it to be replaced as an anti-tank weapon by something more dangerous to civilians).
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January 23rd, 2012 at 3:28 pm
Thanks for your comment(s):
“depleted uranium” is not depleted of fissile matter, as Uranium-238 has 60% fissile, and other radionuclides–sometime plutonium-239 from NPP’s. This matter has a “first: half-Life’ of 4.46 “billion” years’. I call this extreme “contamination aspect not-so-depleted uranium, i.e. NSDU-238 because it, ur-238 is also “natural uranium”! This matter also is low-level contamination which is proven to be more susceptible to women but 5X more than women found in children.
So, ur-238 made into munitions kills by cancers and encephalogic “anti-Mater particulates” which means there is no vacuum-cleanor for use of this anti-matter: mentality. The particulates have been found 1,000’s miles away in northern Europe from both Iraq and from Yugoslavia.
(also)
Sorry for the typos…NPP’s are nuclear power plants… those that have the Mach I cooling system leak immensely. Tritium gas or H3, they are radionuclide as well…all periphery areas from 10-feet (as well as inside buildings and especially beneath) must be measured to distances as far as 100 to 200 miles, as well. This cannot be done w.o. a “digital” metering system which incorporates the proper adjustment of particles. CS-137 and 134. Lastly, this presents there is a need for measurements thruout the continent of north-America, as the “plumes” from Daiichi’s meltdowns have presented a new cache of data, as well as necessity! Since this is not concept from h-Bombs ‘fallout” and a new geographical area is in need of distribution, but of blanket emphasis i.e. everywhere on the continent, due all three correlatives, in other words!
May be these ’stats’ will give some substance to your “lack of research” on the contaminations-Issues ever-so-prevalent, since the first “nuclear-Weapons usages in 1991 by u-s and 1973 by IDF.
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January 23rd, 2012 at 4:05 pm
“R” Addison said:
And thank you for yours.
I learned that
1. Uranium 238 is 60% fissile and sometimes is actually plutonium-239!
2. Uranium 238 also creates “anti-mater [sic] particulates” which are dangerous for some reason because of the lack a “vacuum-cleanor” [sic]. Why this is dangerous remains a mystery.
3. Not knowing how to spell is now known as a “typo.” Not knowing how to think is apparently now realized by posting comments under the pseudonym “‘R’ Addison.”
4. “Mach I cooling systems” are very leaky. If I ever run across one, I’ll be sure to wear my galoshes. Fortunately, however, I’ve never heard of a “NPP” with a “Mach I cooling system.” It must be new.
5. Israel was the first country to use nuclear weapons, and they did so in 1973. Apparently, all of those people in Hiroshima and Nagasaki must have been lying all this time.
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January 23rd, 2012 at 4:16 pm
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January 23rd, 2012 at 5:02 pm
Matthew said:
Actually, I had thought that the reference was made to an outdated version of a Gillette razor.
As anyone who has used an old razor might understand, that could explain the “leaky” part. I, myself, have spent some time leaking after a bad shave.
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January 23rd, 2012 at 8:33 pm
Anon said:
You might be right. There is no standard. It all depends on the economics of a given enrichment technology and the price of uranium at the time.
“R” Addison said:
um…
Ohhhh kay..
First, regarding plutonium-239 in depleted uranium. Pu-239 occurs in uranium ores in the most minute of quantities, and it won’t be found in detectable amounts in most uranium. There are stories of tiny amounts of Pu-239 in some French depleted uranium stocks. It may be that this material was contaminated with uranium sent for re-enrichment after being recovered from spent fuel fuel.
U-238 is not fissile. It’s not fissile at all, by the normal definition of “fissile.” Uranium-238 will fission when it is exposed to super high energy neutrons. This can happen in fast spectrum reactors and in nuclear bombs, but it is still not fissile because it can’t sustain a chain reaction on its own. It does not produce enough neutrons to do so. It therefore may be regarded as “fissionable” by fast spectrum.
It is “fertile” meaning that if it absorbs a neutron it will become Pu-239, which is fissile.
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