Problem 6.246

What must be the relative velocity of a source and an absorber consisting of free $I r^{191}$ nuclei to observe the maximum absorption of gamma quanta with energy $\varepsilon=129 \mathrm{keV}$ ?

Reveal Answer

v \approx \varepsilon / m c=0.22 \mathrm{~km} / \mathrm{s} \text { , where } m \text { is the mass of the } \mathrm{nucleus}

Radioactivity