Question

The maximum characteristic xray photon energy comes from the capture of a free electron into a K shell vacancy. What is this photon energy in keV for tungsten, assuming the free electron has no initial kinetic energy?

a) 69.5 keV
b) 59.3 keV
c) 45.7 keV
d) 72.8 keV

Answer 1

The maximum characteristic x-ray photon energy in tungsten when a free electron fills a K shell vacancy and has no initial kinetic energy is 72.8 keV, slightly less than the minimum 72.5 kV acceleration required.

Step-by-step explanation:

The maximum characteristic x-ray photon energy for tungsten occurs when a free electron is captured into a K shell vacancy without any initial kinetic energy. To calculate this energy, we can use the energy level formula for hydrogen-like atoms, since inner-shell electrons are relatively unaffected by the other electrons in the atom and can be approximated using the same formula.

Given that significant accelerating voltage of at least 72.5 kV is required for tungsten, we can infer that the maximum characteristic x-ray photon energy will be slightly less than this value. Through this information, the correct answer for the maximum characteristic x-ray photon energy in tungsten is 72.8 keV.