Artificial Radioactivity

If the radioactivity is induced in an element by irradiation with, for example, neutrons, the process is known as artificial radioactivity. By irradiation we mean exposure to radiation either by accident or by intent.

Artificial disintegration was first achieved by Rutherford when he disrupted nitrogen nucleus with energetic α-particles, to produce first of all an isotope of fluorine. The fluorine nucleus being unstable disintegrates immediately into an oxygen nucleus and a proton thus:

⁴₂He + ¹⁴₇N → ¹⁸₉F → ¹⁷₈O + ¹₁H + Energy

In artificial radioactivity an ordinary material, not normally radioactive is made radioactive by bombarding it with radioactive particles

⁴₂He + ²⁷₁₃Al

→³⁰₁₅P + ¹₀n → ³⁰₁₄Si + ⁰₁e + Energy

Thus phosphorus nuclei which are not stable but radioactive can be produced by bombarding non-radioactive aluminium with α-particles. The radioactive phosphorus nuclei then disintegrates spontaneously into stable Silicon atoms.

The neutron, the proton and the α-particles have been found very effective bombarding projectiles for disintegrating the nuclei of elements. Examples of such bombardments are:

¹₀n + ⁶₃Li → ³₁H + ⁴₂He + Energy

¹₀n + ²⁴₁₂Mg → ²⁴₁₁Na + ¹₁P + Energy

⁴₂He + ⁹₄Be → ¹²₆C + ¹₀n + Energy

¹₀n + ⁵⁹₂₇Co → ⁶⁰₂₇Co + Energy

Isotopes can be made artificially by bombarding neutrons or protons or deuterons at elements; e.g.

³⁴₁₀S + ¹₀n → ³⁵₁₀S + Energy

⁷⁹₃₅Br + ¹₀n → ⁸⁰₃₅Br + Energy

Such artificially produced isotopes are unstable and decay with the emission of α-particles, β-particles and γ-rays. They are therefore called radioisotopes.

Radioisotopes or radioactivity isotopes are isotopes that are made artificially by bombarding neutrons or protons or deuterons at elements.