Maximum output of radiation at the window surface of XRF analyzer

• A. 500 Roentgen per hour
• B. 100 Roentgen per hour
• C. 10000 Roentgen per hour
• D. 2000 Roentgen per hour

Answer: (D)

Maximum radiation at the window surface is determined by the XRF instrument’s design and shielding—the window is the last barrier before radiation can escape to the operator, so the device specifies an upper leakage limit to ensure safe use. The listed value represents the manufacturer’s guaranteed maximum leakage through the window, used to plan shielding and safe working distances.

2000 Roentgen per hour fits typical design tolerances for window leakage in XRF devices, making it the best choice. Numbers that are much lower would imply unrealistically tight shielding or leakage, while a value as high as 10000 R/h would exceed what most field XRF instruments are designed to emit through the window.