What is Alpha radiation: Definition and 12 Discussions

Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay, but may also be produced in other ways. Alpha particles are named after the first letter in the Greek alphabet, α. The symbol for the alpha particle is α or α2+. Because they are identical to helium nuclei, they are also sometimes written as He2+ or 42He2+ indicating a helium ion with a +2 charge (missing its two electrons). Once the ion gains electrons from its environment, the alpha particle becomes a normal (electrically neutral) helium atom 42He.
Alpha particles have a net spin of zero. Due to the mechanism of their production in standard alpha radioactive decay, alpha particles generally have a kinetic energy of about 5 MeV, and a velocity in the vicinity of 4% of the speed of light. (See discussion below for the limits of these figures in alpha decay.) They are a highly ionizing form of particle radiation, and (when resulting from radioactive alpha decay) usually have low penetration depth (stopped by a few centimeters of air, or by the skin).
However, so-called long range alpha particles from ternary fission are three times as energetic, and penetrate three times as far. The helium nuclei that form 10–12% of cosmic rays are also usually of much higher energy than those produced by nuclear decay processes, and thus may be highly penetrating and able to traverse the human body and also many meters of dense solid shielding, depending on their energy. To a lesser extent, this is also true of very high-energy helium nuclei produced by particle accelerators.

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  1. ErikSwan

    B Can alpha radiation make other materials radioactive?

    Most general sources that describe the basics of ionizing radiation assert that the only type of radiation that can directly make other materials radioactive is neutron radiation (via "neutron activation"). Googling "does radiation make things radioactive?" produces a few examples, for...
  2. S

    A Alpha Stopping Power Database for High Z Materials

    That's about it. I've been trying to do the calculation manually with Bethe-Bloche without corrections in the energy range I'm interested in (1-10 MeV) for the highest Z material with data available for validation (Uranium), but I can't get a result that agree well with the database, so I'm...
  3. E

    Comparing RBE to relative penetrating power?

    Relative biological effectiveness is a factor that radiation dose is multiplied by to account for differences in biological damage by varying types of radiation. RBE is higher for alpha particles than any other, yet the relative penetrating power of alpha radiation is the smallest of the four...
  4. C

    I Why is Proton Radiation this Rare in Nuclear Fission Decay?

    The atomic nuclei consist out electrons, protons and neutrons (with only exception of hydrogen, that does have a neutron). Thus, it would be straightforward, that there existed a corresponding radiation for each nucleus component, when a nucleus decays. There is an electron radiation (beta...
  5. Muhammad Danish

    Can a Gold Leaf Electroscope Detect Alpha Particles?

    Can we use Gold Leaf Electroscope to check whether a radioactive material gives off Alpha particles?
  6. M

    Beta radiation and Alpha radiation

    This might be a very stupid question :(, but I am confused. So I did an experiment. we had radioactive material which was emitting beta particles, and we were using geiger counter to measure pulses (ionized beta particles). We were supposed to measure the time it takes for the geiger counter to...
  7. Garlic

    Can Alpha Emitters Cause Nearby Gasses to Glow?

    Hello everyone, Can alpha emitters cause nearby (gasses or air) to be excited and glow like Radium or Tritium? Is there certain chemicals (maybe like phosphor) that are suitable for it?
  8. Etheryte

    How to detect alpha radiation without a counter?

    Alright if I have an object that's completely constituted of alpha radiation particles (emitting the +2 charge nucleus of a hydrogen atom), how would that be accurately detected taking into consideration that I don't have a Griegor Counter on hand? Americium-241
  9. D

    Where to find an alpha radiation silicon detector? (alpha spectroscopy)

    I am looking for an alpha detector to do an alpha spectroscopy (and maybe beta as well). The rough setup is a vacuum tube with a detector in one end and a source in the other, possibly with a magnet in the middle. I have googled around, but my problem is that I don't really know what is...
  10. A

    Can You Safely Handle Alpha Radiation? The Dangers of Unprotected Exposure

    Say I were to pick up a big chunk of Americium-241. Could I just hold it in my hand or would it be painful? Not that I'm planning on doing it, just out of curiosity.
  11. M

    Is covering a high radioactivity alpha source with a low Z material safer?

    Hi all! I have the following question to solve and it's getting me down. Suppose we have an alpha source with very high radioactivity (such as 100kCu) in our workspace. Even though we know that the range of alpha particles in air is about 4 cm and we try to stay away from the source and...
  12. tandoorichicken

    Exploring Alpha Particle Emission: Energy Release in Am-241 Decay and Beyond

    Whats the energy released when an alpha particle is emitted, say for example, from Am-241 -> He-4 + Np-237 ? Is it the same for all decay reactions?