An 80 kVp X-ray system uses a 2.5 mm aluminium filter, replaced by copper for equal attenuation. Mass attenuation coefficients are 0.02015 m²/kg for Al and 0.07519 m²/kg for Cu; densities are 2699 and 8960 kg/m³. Find copper thickness in mm to two decimals.
Equal attenuation requires equal products of mass attenuation coefficient, density and thickness: (μ/ρ)AlρAl tAl=(μ/ρ)CuρCu tCu. Hence tCu=2.5×.02015×2699/(.07519×8960)≈.2018 mm, rounding to .20 mm. The source uses these effective coefficients for its beam model.
More X-Ray and Computed Tomography questions
GATE 2020 BM Q16– In diagnostic X-ray imaging, which is NOT a primary electromagnetic-radiation interaction…
GATE 2020 BM Q59– A 36 cm ×48 cm chest radiograph is digitized to preserve 6 cycles/mm at 8-bit…
GATE 2020 BM Q60– In the shown 50 keV X-ray path, incident photon count is 2×10⁶. The ray crosses 2 cm soft…
GATE 2024 BM Q15– Which event is NOT typically encountered in diagnostic X-ray projection radiography?
GATE 2024 BM Q27– Monochromatic gamma photons enter homogeneous tissue. Which relationships hold for…
GATE 2024 BM Q48– The graph shows X-ray attenuation coefficients versus photon energy for bone,DCA and…