An Alpha Ray is really a term for a stream of Alpha Particles.
Alpha Particles cannot penetrate the epidermis. However, if inhaled and the decay occurs inside your lungs, there is no protective epidermis which can stop it. Your lungs are easily damaged.
There are two types of particles that are generally involved in radioactive decay-Alpha and Beta particles.
To visualize how these particles are damaging, and how they are different, think of a bullet being shot into gelatin. When these various “bullets” (alpha or beta particles) penetrate human flesh or gelatin, they travel in a line, causing linear damage along their route. But when they come to a stop, they transmit all their remaining energy into the tissues surrounding where it comes to a stop.
A Beta particle is small, but has higher penetrating power. It can get through your skin, but because it is small (about 8000 times less massive than an Apha particle) it has a relatively small “sphere” of destruction. Think of firing a bullet the size of a pinhead which might weigh 4 milligrams (just guessing here) into that gelatin. It is going to be high velocity, will make a very small hole to penetrate, and when it stops, it will radiate damaging energy out a very small distance.
Now, think of a 75 caliber musket ball fired from a musket at low velocity. It weighs nearly 8,000 times as much as the head of a pin. But it travels far slower. When it hits, it may not penetrate as far as that Beta Particle head of a pin and might even be stopped by clothing (using an analogy here, clothing won’t stop stop a 75 caliber musket ball any more than the thin layer of skin stops an Alpha particle) but when it does penetrate into soft tissues, it doesn’t go nearly as far, but when it comes to a stop, it is HUGELY destructive, and the sphere of destruction is massive.
So, an Alpha Particle might not get through the thick skin, but if you inhale it (or eat it) and it gets emitted, there is no skin to stop it, just soft tissue to let it in and absorb it where all the damage will occur to your lungs or to your digestive tract, both of which are vulnerable to radiation damage.
You might have misinterpreted my post which I completely understand, since I have difficulty distilling my posts down.
I am saying the risk is so low as to be nearly non-existent, and that it is overblown for someone’s politcal purposes.
The fact that our troops have been handling depleted Uranium rounds for nearly forty years with zero deleterious effects is empirical proof of their safety.
(note that I only said generally two particles involved in decay. For example, there are also Positrons which are positively charged electrons.
Positrons have an extremely short life. When one is created by radioactive decay, it flies around in the atomic world until it flies too close to a negatively charged electron, its identical twin with the polar opposite charge.
When the positron and electron get close enough, they “capture” each other, and begin a dance of death that results in annihilation which converts both of them entirely to energy, resulting in two photons of radiation, each equal at 511 KeV that fly away from each other at exactly 180 degrees. (This is the basis of PET scanning (Positron Emission Tomography) in Medicine.
The dance of annihilation death for the two particles that get too close involves them capturing each other simultaneously, then they begin to spiral around each other, faster and faster, closer and closer, until they collide, annihilate and disappear, and throw off the two gamma radiation photons that fly away from each other.
And it happens it a time frame so small it is nearly indetectable. (I can’t remember how long a positron lives before it annihilates with some promiscuous electron it meets, but electrons are everywhere in everything, so...it doesn’t take long.
I have always found that fascinating.