Question

A fast-moving electron beam strikes a metal target and produces a sharp peak in emission at one frequency as well as the bremsstrahlung continuum emission.

a) What causes this peak in X-ray spectrum? Explain what happens to the electrons in the metal atom.

b) Can a hydrogen atom emit x-rays? Explain why or why not (be quantitative about photon energy).

Answer 1

1> Question > What causes this peak in X-ray spectrum? Explain what happens to the electrons in the metal atom.

Answer::

Characteristic radiation is due to the a charged particle kicking out an electron from an inner orbit and an outer electron drops down into its spot.

Characteristic X-rays are produced when an element is bombarded with high-energy particles, which can be photons, electrons or ions (such as protons). When the incident particle strikes a bound electron (the target electron) in an atom, the target electron is ejected from the inner shell of the atom. After the electron has been ejected, the atom is left with a vacant energy level, also known as a core hole. Outer-shell electrons then fall into the inner shell, emitting quantized photons with an energy level equivalent to the energy difference between the higher and lower states. Each element has a unique set of energy levels, and thus the transition from higher to lower energy levels produces X-rays with frequencies that are characteristic to each element.

Bremsstrahlung is  “breaking radiation”, the radiation emitted in a continuous spectrum as a charged particle slows down in a material.

braking radiation" or "deceleration radiation", is electromagnetic radiation produced by the deceleration of a charged particle when deflected by another charged particle, typically an electron by an atomic nucleus. The moving particle loses kinetic energy, which is converted into radiation (i.e., a photon), thus satisfying the law of conservation of energy. The term is also used to refer to the process of producing the radiation. Bremsstrahlung has a continuous spectrum, which becomes more intense and whose peak intensity shifts toward higher frequencies as the change of the energy of the decelerated particles increase.

2>

hydrogen atom has one proton and one electron. ... But hydrogen is also the least energetic element. Even the most energetic line hydrogen emits (when an electron drops down from the second shell to the first) has only enough energy to be an ultraviolet photon. So hydrogen atoms do not emit X rays.