Having looked at some of the finer details for beta decay in two previous posts (Q-Value and Metastable Nuclei) it seems fitting to round-off this short series with two phenomena that involve orbiting electrons rather than just nucleons. The first effect is electron capture. As its name suggests, this is when an orbiting electron is … Continue reading Electron Capture and Internal Conversion
Technetium-99m
At first glance the decay of molybdenum-99 to produce technetium-99 is a straightforward beta process. The total number of nucleons is unchanged but the number of protons increases by one with the emission of an electron and an electron-antineutrino. The half-life for this decay is 66 hours. In the nuclear decay equation above, technetium-99 is … Continue reading Technetium-99m
Beta Decay Q-value
At GCSE level, beta decay is said to be the emission of an electron (or positron, in beta-plus decay) when an unstable nucleus transforms into a more stable nucleus. The parent and daughter nuclei are different elements with the same nucleon number (sum of neutrons and protons) but their proton numbers vary by +1 for … Continue reading Beta Decay Q-value
Beta Decay and Energy Conservation
I have just finished reading an excellent book that traces various theories about beta decay in the first third of the Twentieth Century. Controversy and Consensus: Nuclear Beta Decay 1911-1934 is an editted version of the successful PhD thesis written by Carsten Jensen, who clearly had a deep passion for unravelling physics history but died … Continue reading Beta Decay and Energy Conservation
Hideki Yukawa and Meson Theory
How does the nucleus of an atom stay together? Why don’t the positively-charged protons repel each other and cause the nucleus to disintegrate? The early models of the atom imagined solid spheres, perhaps with different sizes, shapes or “colours” distinguishing one type of atom from another. Then came J J Thomson’s discovery of the electron … Continue reading Hideki Yukawa and Meson Theory
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