Which isotope is listed as an XRF exposure option in the source material?

Which isotope is listed as an XRF exposure option in the source material?

• A. Cobalt-57
• B. Cadmium-109
• C. Lead-210
• D. Uranium-238

Answer: (B)

In XRF (X-ray fluorescence) work, the irradiation source must emit X-rays at energies that efficiently excite the elements in a sample so their characteristic X-rays can be detected. Cadmium-109 is commonly used as an XRF exposure source because it emits relatively low-energy X-rays around 22 keV, which are well-suited to exciting a wide range of elements and producing a strong, measurable fluorescence signal. This makes cadmium-109 a standard, practical choice for XRF instrumentation and training materials. The other isotopes listed are not typical XRF excitation sources. Cobalt-57 is mainly a calibration/gamma source and not optimized for XRF excitation. Lead-210 and Uranium-238 are primarily associated with other radiological contexts (alpha decay and long-lived radionuclides) and are not used as X-ray excitation sources in standard XRF practice. So cadmium-109 stands out as the isotope listed for XRF exposure due to its appropriate X-ray emission characteristics and widespread use in XRF instrumentation.

In XRF (X-ray fluorescence) work, the irradiation source must emit X-rays at energies that efficiently excite the elements in a sample so their characteristic X-rays can be detected. Cadmium-109 is commonly used as an XRF exposure source because it emits relatively low-energy X-rays around 22 keV, which are well-suited to exciting a wide range of elements and producing a strong, measurable fluorescence signal. This makes cadmium-109 a standard, practical choice for XRF instrumentation and training materials.

The other isotopes listed are not typical XRF excitation sources. Cobalt-57 is mainly a calibration/gamma source and not optimized for XRF excitation. Lead-210 and Uranium-238 are primarily associated with other radiological contexts (alpha decay and long-lived radionuclides) and are not used as X-ray excitation sources in standard XRF practice.

So cadmium-109 stands out as the isotope listed for XRF exposure due to its appropriate X-ray emission characteristics and widespread use in XRF instrumentation.