Types of Radiation 1/3: Alpha and Beta

How many types of nuclear radiation are there? Don’t look on Wikipedia, that would be cheating.  Post all the kinds you can think of in the comments below. I’ll give you a hint, there are more than four but I’ll just talk about these specific 4 in this series of posts: Alpha, Beta, Gamma, and Neutron as they are the most common types that a person would interact with on earth.

Apparently we have a serious shortage of helium. I blame Instagram “influencers”.

Have you ever taken a big breath from a helium balloon to make your voice squeaky? Congratulations you have had a lungful of alpha radiation! I’m only partly joking, the vast majority of helium on this planet was formed from the radioactive decay of elements contained in certain rock formations, usually granite or something similar. And the reason for that is because alpha radiation is just helium atoms without any electrons that are moving really fast.

When alpha radiation occurs, a single atom in a sample kicks out an alpha particle, which as we discussed is simply a helium nucleus doing 130 mph in a 60 zone. And just like that metaphor, it is actually just the speed of the particle that makes it dangerous to people. If it gets inside you it can easily break any molecular bond it barrels into, and if it hits a DNA strand it will almost certainly do irreparable damage to that strand. However! Among types of radiation, alpha radiation is actually an enormous lumbering elephant. Despite what that sounds like it’s actually a very good thing, as in this situation is means it cannot sneak through any gaps between atoms. So it will bounce off of essentially the first thing it comes into contact with and lose energy with every collision. And that process of losing energy is how the alpha particle slows down enough to snag a couple passing electrons and become a nice safe helium atom. In fact, Alpha particles are so bad at sneaking through materials that effectively all alpha radiation you have ever been exposed to has been blocked by the layer of dead skin you have. So how does it feel to be radiation proof?

Thus the only ways you are in danger from alpha radiation is if it gets inside you from either inhalation, ingestion or injection. Seeing as how these possible vectors can be negated by respectively wearing a dust mask, not licking or eating strange substances, and not letting any random person stab you with a syringe full of mystery fluid, you can start to see that alpha radiation is not a very big concern in day to day life.

A little piece of Canadian nostalgia, I doubt they thought that it would be used as pretty reliable radiation safety advice though.

Moving on to Beta Radiation. Unlike alpha radiation, beta radiation doesn’t remove any particles from the nucleus but instead, it arises from a random neutron in the nucleus splitting into a proton and an electron. The proton stays in the nucleus and the electron is ejected at high speeds. There are some direct uses for beta radiation such as what at called beta-batteries that harvest these high-speed electrons directly for energy. But other than that one electron is fundamentally identical to every other electron, only the amount of energy contained within its momentum and the source of them differentiates them from the same electrons that power your fridge or make your phone work.

Where alpha radiation is a big lumbering particle with a large amount of energy in it, a beta particle is much smaller and even though it usually has less energy, due to its significantly smaller mass it travels much much faster. Does this mean that beta radiation is like some kind of radioactive ninja, able to sneak through any gap in between even the most tightly packed atoms to find you while you are sleeping and give you cancer?

via GIPHY

Where alpha radiation can be stopped by things like paper and dead skin, beta radiation requires a sheet of metal foil to be blocked, making it the only time when a tinfoil hat will actually keep you safe from something. An added bonus that since beta radiation is nothing but electrons, if it is captured with a conductive material like aluminum foil you can actually create a current capable of powering some small electrical devices. Thus beta radiation can not only be safely blocked but also directly harvested to create electricity. If you have ever heard of something called a beta-battery, then you have heard of this exact method of harvesting energy. And since the energy is harvested to do work there is no danger of harm coming from such harvested radiation.

Another layer of safety that can be utilized against alpha and beta radiation is the use of magnetic fields. Since both alpha and beta particles have electrical charges (+2 for alpha and -1 for beta) they can be deflected from hitting an object by surrounding that object with a sufficiently large magnetic field. This is actually how the earth’s magnetic field helps protect us down here from being bombarded with even more radiation than we already are from our sun and other cosmic sources. It has also been proposed as a method of protecting manned interplanetary spacecraft that we might one day send to Mars and beyond.

Alpha and beta radiation can be harmful to us, but are easily shielded, deflected, or harnessed for our uses. The next sections of this series cover gamma and neutron radiation which are a bit harder to deal with, but one of them is more useful to us than all the gold in the world.

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6 thoughts on “Types of Radiation 1/3: Alpha and Beta

Add yours

  1. “…if it [alpha particle] hits a DNA strand it will almost certainly do irreparable damage to that strand…”
    You cannot possibly know that, can you? And if you don’t know, maybe you should consider deleting ‘irreparable’?
    Double Strand Breaks [DSBs] in DNA, caused by ionising radiation DOES activate a DSB Repair Mechanism. A simple folate dietary deficiency causes massive levels of DSBs, but – DOES NOT activate the DSB Repair Mechanism.
    Proof, if proof were needed that we evolved in an ocean of background radiation levels much higher than they are today and, I suspect, though I don’t know, it is a conserved trait going back to the first single cell eukaryotes:
    https://www.ncbi.nlm.nih.gov/pubmed/14597554

    Like

  2. “…if it [alpha particle] hits a DNA strand it will almost certainly do irreparable damage to that strand…”

    You cannot possibly know that, can you? And if you don’t know, maybe you should consider deleting ‘irreparable’?

    Double Strand Breaks [DSBs] in DNA, caused by ionising radiation DOES activate a DSB Repair Mechanism. A simple folate dietary deficiency causes massive levels of DSBs, but – DOES NOT activate the DSB Repair Mechanism.

    Proof, if proof were needed that we evolved in an ocean of background radiation levels much higher than they are today and, I suspect, though I don’t know, it is a conserved trait going back to the first single cell eukaryotes:

    https://www.ncbi.nlm.nih.gov/pubmed/14597554

    Like

    1. To break an atomic bond in DNA takes approximately between 100-1000 kJ/mol depending on which atoms are bonded. That works out to approximately 5 eV per bond on average. An alpha particle from a U235 decay has ~4,679,000 eV of energy. In ideal conditions, it could cause almost 1 million bond breaks per alpha particle which would all happen in the time frame of microseconds rather than the days or weeks of a dietary deficiency. And not simply separating base pairs, but actually shattering the molecules themselves. There is a reason that there is a lot of interest in using nano-dose bismuth isotopes for alpha radiation therapy against malignant cancer cells, because alpha radiation is extremely damaging to cells, but is too short ranged to affect them from external sources. Is irreparable a hyperbolic statement? possibly. But it is not as inaccurate as some might hope.

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