The

A, B, G’s

( α,  β,   γ )

of

Nuclear Radiation

 

 

By:  David Deschesne

Editor/Publisher

Fort Fairfield Journal, May 6, 2020

 

   Radiation comes in many flavors.  There are two primary forms, though; Electromagnetic and Nuclear.

   Electromagnetic is essentially that found in the radio frequency (RF) spectrum.  Think of those miniature microwave transmitters you hold next to your head, called “cell phones.”  They transmit the exact same frequencies into your ear and brain that are used in microwave ovens to cook food, though cell phones transmit at much lower power levels.  Ergo, you’re on “slow bake” when you’re holding one of those stupid (not “smart”) devices next to your head, or reproductive organs.  [I say, “you” because I have never owned a cell phone in my life, and still don’t, but I digress.]

   Other forms of electromagnetic radiation are radio waves, UV rays, visible light, and X-rays like you get at the hospital.   While high levels of any of this type of radiation can be dangerous, it is not the topic I’m fixin’ to discuss here.

   Nuclear Radiation is what most people think about when they hear the word, “radiation.”  It is produced by the decay of an atom, throwing off one of its internal particles at high speed, or an energy wave, with a great amount of energy.  A few of these particles  or waves together is no big deal and merely contribute to the normal background radiation our bodies have adapted to live in.  Too many of the right type of high energy particles together, though, can create an atomic bomb.

   What makes radiation dangerous, even at moderate levels, is an effect it has on other atoms and cells, called ionization.  Like your microwave-based cell phone, which beams ionizing radiation into your head, nuclear ionizing radiation can also scramble the DNA in your cells and/or oxidize your cells, creating free-radicals which can lead to various forms of cancer and other tissue damage.

 

Types of Nuclear Radiation

 

α

Alpha Particle

   The first type of radioactive particle is the alpha particle. Alpha radiation occurs when an atom, undergoing radioactive decay, throws off two protons and two neutrons from its nucleus.  Due to their charge and heavy mass, alpha particles interact strongly with matter and only travel a few inches in the air.  Alpha particles can be stopped by a simple sheet of paper and are unable to penetrate the top layer of dead skin cells on your body.  However, if they are ingested in food or water in high enough amounts they can cause a tremendous deal of damage to your internal organs as they come into contact with them.

 

β

Beta Particle

   Beta radiation takes the form of either an electron or a positron.  A positron is a particle with the size and mass of an electron, but with a positive charge.  Due to its smaller mass, a Beta particle can travel further in the air, out to around 10 or 12 feet.  It can be stopped by a thick piece of plastic, or even a stack of paper.  Beta particles can penetrate the skin a few inches and thus can pose somewhat of a health risk.  But, like alpha particles, the primary health risk for beta particles is from ingesting them in food or water.

 

γ

Gamma Radiation

   Unlike Alpha or Beta radiation, Gamma radiation does not consist of any particles.  It is essentially a high energy electromagnetic wave that is emitted from the nucleus of an unstable atom.  Since it is a wave, it has no mass or charge and can travel much longer distances.  Gamma waves cannot be stopped by paper or plastic.  Electromagnetic Pulses from nuclear explosions emit high amounts of high energy gamma rays which are the cause of destruction to electronic equipment.  Shielding for gamma waves is usually done with lead, or depleted uranium.

 

X-Ray Radiation

   This is the type most people are familiar with.  X-ray radiation is used in hospitals and dentist offices to create images of the inside of the human body for diagnostic purposes.

   X-rays are a little bit lower in frequency and energy than gamma-rays but can still be just as damaging in high enough exposure levels.  The way X-rays differ from gamma-rays is that they originate from an atom’s electron cloud, rather than the nucleus.

   When you think of X-ray and Gamma-ray radiation, think of really high frequency light.  Starting with microwaves in the electromagnetic spectrum, as we move up in frequency we get to infrared waves, then visible light, then UV light, then X-ray and finally Gamma-ray.

 

Neutron Particle

   Neutron radiation is produced when a free neutron is emitted from the nucleus of an atom, usually as a result of spontaneous or induced nuclear fission.  Neutrons are able to travel for miles through the air but they can be stopped by a hydrogen-rich material such as water or concrete.  Neutrons are typically non-ionizing radiation because they do not posses an electric charge.  But, they can cause the atom that absorbs them to become unstable and emit ionizing radiation.  This makes neutrons the only type of radiation that can make other materials radioactive.

 

In the world around us

   When most people think of nuclear energy, they think of its failures.  Fukushima comes most readily to mind, then Chernobyl and finally, for people my age, Three-Mile Island.

   While those nuclear power plants did fail and released various amounts of radiation into the environment, there are plenty of other naturally occurring radiation sources in the environment, too.

   The harmful effects of radiation is measured in Sieverts (Sv).  To give a frame of reference, 4 sieverts is a fatal dose, but a person can survive if treated quickly.  8 sieverts is lethal instantly.

   Luckily, the background radiation we are exposed to on a daily basis is at much lower sievert levels and is measured in microsieverts (μSv), or millionths of a sievert. 1 μSv is expressed as the decimal: 0.000001 sieverts.

  The potassium in a typical banana is around 0.1 μSv.  The potassium-40 in bananas is a radioactive isotope which occurs naturally in some foods.  There was a time when radiation exposure was actually measured in bananas.  For example, a dental X-ray is equivalent to eating 500 bananas all at once.  A mammogram is equivalent to eating 4,000 bananas and a fatal dose of radiation is equivalent to eating 80 million bananas.  So, don’t give up bananas.  If you eat them, you’ll be okay.

   Brazil nuts are also radioactive in the same way as bananas.  In fact, the ground radiation at Guarapari, Brazil emits about 10,000 μSv per year.  To give a frame of reference, 100,000 μSv is the upper limit permitted for emergency work in some countries.

   The higher you go in the atmosphere, the more (cosmic) radiation you’ll be exposed to.  Pilots in airplanes that travel frequently in the cruising altitude of long-range jets are usually monitored for radiation exposure.  A typical passenger on a trans-Atlantic flight, though, will only receive about 0.000025 sieverts of radiation, so occasional flying isn’t really a problem.

  But, what about the radiation in food that got there via non-natural, or man-made sources.  For example, what about the tuna fish swimming around off the shoreline of Fukushima, Japan then ending up getting caught, processed and stuck in a can that ends up on your grocery store shelf?  There are ubiquitous amounts of websites out there funded by independents who claim this food source is dangerous, while government-and industry-funded websites say the tuna is “completely safe.”  For the most part, both sides are probably right, depending on which specific tuna one is referring to.

   Testing food for radiation poisoning requires some pretty sophisticated, complex and necessarily expensive equipment.  However, some lower-cost Geiger counters can provide users with a cursory analysis of their food, which would indicate if the fish they’re looking at actually swallowed - and was thus processed with - an actual radioactive particle.  Ingesting that could be dangerous, so those who are concerned can use a simple meter, like the one pictured above, to give a broad sample overview of their food.

   For more precise measurements of food, you need specialized ovens to cook the food down to ash in order to concentrate the radioactive material, then a device called a scintillation meter is used to get much more precise measurements.  Scintillation meters can cost several thousands of dollars so only the most motivated enthusiast is likely to acquire one.  

   Geiger Counters are good to have for general purpose testing and monitoring of your food and environment and they don’t cost a lot of money.  Most simple counters can be had for a little over $100.  But, the time to buy them, like any emergency preparedness item, is not in the middle of an emergency.  During the 2011 Fukushima reactor meltdown, it was nearly impossible to buy Geiger counters because everyone was trying to get one at once - similar to the Great Toilet Paper Debacle of 2020.

 

Irradiation

   In addition to imaging, radiation is also used in the health care industry to sterilize medical equipment and rooms.  The instruments are placed in airtight bags, to ensure that they remain sterilized until it is time to use them.  Care must be taken, though, since too much radiation can break down certain metals.

   Food is another product that is being treated with radiation to kill microorganisms, pathogens and bacteria.  Some countries have legislation prohibiting irradiation of certain foods while others have requirements that some imported foods must be irradiated for pest control, such as fruit flies.

   Exposing food to radiation doesn’t in and of itself make the food radioactive.  Radiation used in this process is usually in the form of Gamma- or X-rays.  Remember, only Neutron radiation can make another material radioactive.

  Opponents of food irradiation argue that the process breaks down some of the essential vitamins in food, thus depleting them of their nutritional value.  They also cite the good bacteria or “pro-biotics” that some foods contain would also be destroyed by the irradiation process.  They also point to the environmental dangers of producing the radioactive products themselves - such as Cobalt-60 - and its transport to the processors then it ultimately being discarded as nuclear waste when it is no longer effective, but still radioactive.

   Many countries only allow the irradiation of spices and herbs.  However, the nuclear industry is continually lobbying legislatures to allow them to expand into meat, grains, fruits and vegetables.

 

Overall Exposure

   Most people living in rural environments will be exposed to a miniscule 0.003 Sieverts of naturally occurring background radiation per year.  People who live in larger cities and get an occasional dental X-ray may be exposed to around 0.006 Sieverts per year.   Nuclear power plant workers are limited by safety guidelines to receiving no more than 0.05 Sieverts per year in total radiation exposure.

   Workers in high-radiation fields can wear a portable dosimeter to give them an indication of how much radiation they are currently exposed to, and how much they have been exposed to over a given time period.

   Most people, however, don’t need to take such stringent precautions.  A decent Geiger counter for general purpose monitoring of the immediate environment will do fine.