XRF uses radiation to excite electrons. Which type of radiation is used in this process?

XRF uses radiation to excite electrons. Which type of radiation is used in this process?

• A. Gamma rays
• B. Ultraviolet
• C. Infrared
• D. Microwaves

Answer: (A)

XRF works by using photons energetic enough to knock electrons out of the inner shells of atoms. To create those vacancies, the incident radiation must have energy greater than the binding energy of core electrons. Of the options given, gamma rays are the high-energy photons capable of ionizing inner-shell electrons. Ultraviolet photons are typically too weak to do this, and infrared and microwaves are far too low in energy. Once a core hole is formed, electrons from higher levels fill the vacancy and emit characteristic X-rays, which the detector uses to identify elements.

XRF works by using photons energetic enough to knock electrons out of the inner shells of atoms. To create those vacancies, the incident radiation must have energy greater than the binding energy of core electrons. Of the options given, gamma rays are the high-energy photons capable of ionizing inner-shell electrons. Ultraviolet photons are typically too weak to do this, and infrared and microwaves are far too low in energy. Once a core hole is formed, electrons from higher levels fill the vacancy and emit characteristic X-rays, which the detector uses to identify elements.