The radiation source used in XRF analyzers for lead paint inspection comes from which isotope?

The radiation source used in XRF analyzers for lead paint inspection comes from which isotope?

• A. Cadmium-109 Isotope
• B. Cobalt-57 Isotope
• C. Cesium-137 Isotope
• D. Iridium-192 Isotope

Answer: (B)

XRF works by irradiating a sample with radiation so that atoms in the paint emit characteristic X-rays that identify the elements present. The energy of the excitation source is chosen to efficiently cause lead atoms to fluoresce and produce a clear lead signal in the detector. Cobalt-57 provides photons in an energy range that effectively excites lead’s inner shells in painted surfaces, yielding a strong, detectable lead signal while keeping radiation exposure practical for handheld analyzers. The other isotopes listed either emit photons that are not as effective for exciting lead’s X-ray lines or would not provide the same reliable excitation for paint coatings, making cobalt-57 the best match for this purpose.

XRF works by irradiating a sample with radiation so that atoms in the paint emit characteristic X-rays that identify the elements present. The energy of the excitation source is chosen to efficiently cause lead atoms to fluoresce and produce a clear lead signal in the detector. Cobalt-57 provides photons in an energy range that effectively excites lead’s inner shells in painted surfaces, yielding a strong, detectable lead signal while keeping radiation exposure practical for handheld analyzers. The other isotopes listed either emit photons that are not as effective for exciting lead’s X-ray lines or would not provide the same reliable excitation for paint coatings, making cobalt-57 the best match for this purpose.