Question for radiation experts - Best way to measure radiation/particles in rain?

After watching dozens of YT videos with some persons 'measuring' the rain I noticed that mostof this videos really proves nothing. Often these videos start with a dirty pad already in their hand just holding it to their (also often not specified) geiger counter showing some random numbers. In now way it's prove that they really measure the rain and not any test substance added to the ground or whatever.

As I own my own geiger counter I would like to take my own measurements. Now the big question to all experts: How to do it best. Is it really a good idea to use a towel or paper to clean a surface and measure this towel with all the water/particles soaked up?

Is it possible (or maybe better) to collect a few liter rain in a bucket and use a coffee filter to filter this water afterwards. Are those holes in a coffee filter small enough to hold back the radioactive particles? If a coffee filter isn't good enough maybe some other comon part we all own in our houses?

Please tell me who to take serious measurements at home as I've seen enough videos with either faked or unscientific content.

Added: My geiger counter is one of those calibrated devices capable of measuring alpha, beta and gamma.

I am not an expert but I spoke with a scientist who was once. He recommended putting it in a waterproof plastic bag and exposing it on the pavement to rain for a bit. I have to say I am skeptical. Another hint was to hold it close to drains and gutters...the radiation counts are likely to be higher there. Same with fine silt or grit in the street...such fine particles naturally carry radiation quite well. However, you do not want to get the machine wet. It seems that measuring anything besides air (including solids and liquids) with most geiger counters is problemmatic.

Originally posted by Never DespiseHe recommended putting it in a waterproof plastic bag and exposing it on the pavement to rain for a bit.

I'm not sure that this will work as I learned that a plastic bag can shield alpha radiation?
As some of those videos in the internet (if not faked) suggest that the contamination emits alpha (Plutonium?) this would exclude these particles from the measurement.

I don't see why leaving a bucket out in the rain and then hovering the meter over it the next day wouldn't get the same if not better results.

reply to post by ThinkingCap

The problem is that alpha radiation is easily shielded. If you have a few liters of water in the bucket all the particles below surface can't be measured as the water above them shields the radiation. Even a few inches of air shields alpha radiation. If you filter all this water through a filter all these particles are collected in a small place where you can measure them.

Not sure about the shielding effect on gamma emission if it's just a few inches of water above them. I guess that all these particles are heavier than water and collect on the ground of the container.

Here's just an idea, maybe one of you can back it up or shoot it down...what about holding it above water and then holding it above water from a known-non-radiated source. The problem of course is obtaining a sample that could be reasonably thought to be nonradiated. The example that comes to mind is bottled water that had been bottled before Fukushima. You could then compare the relative difference. Even if the reading couldn't tell you the radiation in absolute terms, might it be able to provide a "percent off baseline" type of reading?

I live on the west coast, and I have spent today looking into readings around Sacramento area. Seems to be very low over here. A click a minute.

I would use a cup/bucket.

Once you have collected half an inch of water take it inside and stick the gieger-muller into the cup/bucket and hold the tip just above the surface of the water.

Do not get the geiger-muller wet!!!!!!!!!!

The gieger-muller will have approx 500volts running through it and while the current flow isn't enough to hurt you, you could short out the geiger-counter and turn it into a one use smoke machine.

Remember to take a background reading of the cup/bucket before putting it out into the rain.

Good luck and please come back and let us know what your readings are.

To add... The time for the readings should be roughly the same.

Run 1 gallon of rain water thru a coffee filter.

Put the coffee filter over your geiger counter and record your findings.

Tellurium 132 has a half life of 100 hours. If you see a drop after 100 hours, there you go.


You calculate the drops in radiation to the half lifes of the radioactive elements in the atmosphere from Fukushima. You have to find the half lifes for each particle.

This is the worst one in the rain:
en.wikipedia.org...

Plants think it's potassium or magnesium and put it into their fruits/vegetables. You eat it and your body thinks it's potassium/magnesium and puts it into your bones/tissue.

The rain's radioactive. The Fallout from Fukushima is way worse than Chernobyl.

Also if you see a drop in 30 or so years that would the the cs-137

Originally posted by UnixFE
reply to post by ThinkingCap

 

The problem is that alpha radiation is easily shielded. If you have a few liters of water in the bucket all the particles below surface can't be measured as the water above them shields the radiation. Even a few inches of air shields alpha radiation. If you filter all this water through a filter all these particles are collected in a small place where you can measure them.

Not sure about the shielding effect on gamma emission if it's just a few inches of water above them. I guess that all these particles are heavier than water and collect on the ground of the container.

Most standard geiger counters don't measure alpha and beta radiation. They are only measuring gamma (ionizing) radiation. In order to measure alpha and beta you require an instrument that has been fitted with a special device for measuring it and calibrated.

Alpha and beta emitters can be blocked by clothing, paper, etc, but these particles are easy to ingest or inhale and especially dangerous internally.

When measuring radiation you want to pick up as many particles as you can. Since radiation is getting deposited on surfaces via rain-out coming from Fukushima this is the most likely way to get a reading (ie: off a wet outdoor surface). You could also wipe a dry surface, or just measure the air, or just hold the meter up to just about anything, it is up to you.

If measuring a wet surface, using a towel wipe the surface. Put your counter in a baggie so that no radiation gets on the device but it can read through thin plastic. Hold the towel under the device. Depending on how your instrument is calibrated, ie: CPM, rems, milli/microseiverts you will get the gamma reading.

Here is a handy guide to radiation: radiation

reply to post by Wertwog

My device is capable of reading alpha, beta, gamma and x-ray radiation and it's calibrated to Sieverts ($500 device) taking automated readings every 2 seconds with alarm and internal storage. As I always carry this device with me I hope that it will detect any gamma source automatically as this type of radiation will penetrate the bag etc.

I'm especially ask for the detection of alpha radiation as it's so easily shielded. Even if the rain is contaminated but the 5x5 inch part I try to measure is clean it wouldn't detect the contaminated part right around the corner. At least that's how I understand alpha radiation and the need to collect a large area to concentrate it right below the sensor (a LND712tube).
That's why I ask for the best way to collect those particles out of the rain and what kind of filter is required.

Originally posted by UnixFE
reply to post by Wertwog

 

My device is capable of reading alpha, beta, gamma and x-ray radiation and it's calibrated to Sieverts ($500 device) taking automated readings every 2 seconds with alarm and internal storage. As I always carry this device with me I hope that it will detect any gamma source automatically as this type of radiation will penetrate the bag etc.

I'm especially ask for the detection of alpha radiation as it's so easily shielded. Even if the rain is contaminated but the 5x5 inch part I try to measure is clean it wouldn't detect the contaminated part right around the corner. At least that's how I understand alpha radiation and the need to collect a large area to concentrate it right below the sensor (a LND712tube).
That's why I ask for the best way to collect those particles out of the rain and what kind of filter is required.

Detecting Alpha and Beta particles in liquids requires an even more specialized (and expensive) piece of equipment that what you have. Usually only found in labs, an alpha spectrometer, uses a process called Alpha-particle spectroscopy. Unfortunately you won't be able to do this with your device, but it will pick up dry particle emissions within short-range.

Good luck!

Originally posted by Wertwog
Detecting Alpha and Beta particles in liquids requires an even more specialized (and expensive) piece of equipment that what you have.

Have you seen the YT video about the guy in Toronto? Can you tell me if this video is faked as he states to measure alpha particles with an older device. If it's not possible to measure alpha emmission with such a device and he can shield the emmission with his hand (at least he told us that he does it) we can assume that this video is faked? Or is it possible that low energy gamma radiation can be shielded with just the hand between the source and the detector?

Originally posted by UnixFE

Originally posted by Wertwog
Detecting Alpha and Beta particles in liquids requires an even more specialized (and expensive) piece of equipment that what you have.

Have you seen the YT video about the guy in Toronto? Can you tell me if this video is faked as he states to measure alpha particles with an older device. If it's not possible to measure alpha emmission with such a device and he can shield the emmission with his hand (at least he told us that he does it) we can assume that this video is faked? Or is it possible that low energy gamma radiation can be shielded with just the hand between the source and the detector?

The video seems authentic to me if this is the same video you are referring to;


You can measure alpha emissions with the appropriate device, you misunderstood me. What I was saying was you can't measure alpha particles in LIQUID without spectroscopy.

He is using the Eberline HP260 paddle (beta/gamma) Here's one. with what looks like a Ludlum Model 3 - Survey Meter. This isn't really a Geiger counter in the traditional sense. He isn't using the alpha wand (scintillator) that would go with this device, something like Ludlum Alpha Scintillator. Geiger counters pick up low level radiation a bit better but ion chamber devices measure different types better.

Source
Because they can display individual ionizing events, GM counters are generally more sensitive to low levels of radiation than ion chamber instruments. By means of calibration, the count rate can be displayed as the exposure rate over a specified energy range. When used for gamma radiography, GM meters are typically calibrated for the energy of the gamma radiation being used. Most often, gamma radiation from Cs-137 at 0.662 MeV provides the calibration. Only small errors occur when the radiographer uses Ir-192 (average energy about 0.34 MeV) or Co-60 (average energy about 1.25 MeV).

Since the Geiger-Müller counter produces many more electrons than a ion chamber counter or a proportional counter, it does not require the same level of electronic sophistication as other survey meters. This results in a meter that is relatively low cost and rugged. The disadvantages of GM survey meters are the lack of ability to account for different amounts of ionization caused by different energy photons and noncontinuous measurement (need to discharge).

Alpha and beta emissions can be readily stopped with your hand/paper/clothing, but internally they are dangerous. Gamma radiation will pass right through his hand (like an x-ray) His device is measuring the beta (not alpha) and gamma strikes being emitted from the surfaces (gamma) effecting the gas in the chamber. He isn't measuring the beta and alpha particles that exist 'within' the medium (ie: water). Hopefully that is clearer for you.

Source
Gas filled detectors consists of a gas filled cylinder with two electrodes. Sometimes, the cylinder itself acts as one electrode, and a needle or thin taut wire along the axis of the cylinder acts as the other electrode. A voltage is applied to the device so that the central needle or wire become an anode (+ charge) and the other electrode or cylinder wall becomes the cathode (- charge). The gas becomes ionized whenever the counter is brought near radioactive substances. The electric field created by the potential difference between the anode and cathode causes the electrons of each ion pair to move to the anode while the positively charged gas atom is drawn to the cathode. This results in an electrical signal that is amplified, correlated to exposure and displayed as a value.

The only problem I have is he is contaminating the paddle every time he touches a surface. This should be avoided. If you are measuring just gamma you can cover your device with a plastic baggie, but a beta or alpha instrument should be wiped off and the tissue discarded.

Hopefully that is helpful to you.

reply to post by Wertwog


Sorry, I should clarify just a bit. Beta particles can pass through many objects but loose much of their energy in the process depending on the material. They can pass through human tissue (somewhat) and paper but decelerate in the process. They can be blocked by many metals, such as aluminum - it's considered a 'medium' penetrating radiation. When they pass through living tissues they can kill or damage cells, and cause mutations in DNA.