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• wavelength vs. frequency• photon• kV vs. keV• ionizing radiation• spectrum
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![Page 3: Spectrum - Pusan National Universitybml.pusan.ac.kr/.../IntroMedEng/2020/03_Spectrum.pdf · 2020. 8. 29. · 1.5 Wavelength À, 2.5 Figure 2.2 (a) Scheme of an X ray tube. (b) Intensity](https://reader033.vdocuments.mx/reader033/viewer/2022060911/60a5e38ba1633e77fd751f94/html5/thumbnails/3.jpg)
Visible light
• Electromagnetic (EM) radiation with wavelengths between 400 and 700 nm• Each wavelength corresponds to a different color
– Monochromatic vs. polychromatic colors– Monoenergetic vs. polyenergetic energy– Spectrum
• Spectroscopy
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![Page 4: Spectrum - Pusan National Universitybml.pusan.ac.kr/.../IntroMedEng/2020/03_Spectrum.pdf · 2020. 8. 29. · 1.5 Wavelength À, 2.5 Figure 2.2 (a) Scheme of an X ray tube. (b) Intensity](https://reader033.vdocuments.mx/reader033/viewer/2022060911/60a5e38ba1633e77fd751f94/html5/thumbnails/4.jpg)
Frequency is equivalent to an energy
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• Waves– The speed of EM radiation is constant– 𝑐 𝜆𝜈 (m Hz = m cycles/s = m s‐1)– e.g., What is the frequency (𝜈) of blue light with a wavelength (𝜆) of 400 nm?
• 𝜈 / /
7.5 10 s 7.5 10 Hz
• Particles– Photons: the discrete (particle‐like) packets (or quanta) of EM energy
– 𝐸 ℎ𝜈• ℎ = Plancks constant = 6.626 10 J s = 4.136 10 keV s
– 𝐸 keV .
or 𝐸 eV .
![Page 5: Spectrum - Pusan National Universitybml.pusan.ac.kr/.../IntroMedEng/2020/03_Spectrum.pdf · 2020. 8. 29. · 1.5 Wavelength À, 2.5 Figure 2.2 (a) Scheme of an X ray tube. (b) Intensity](https://reader033.vdocuments.mx/reader033/viewer/2022060911/60a5e38ba1633e77fd751f94/html5/thumbnails/5.jpg)
X‐ray spectrum as a function of wavelength
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![Page 6: Spectrum - Pusan National Universitybml.pusan.ac.kr/.../IntroMedEng/2020/03_Spectrum.pdf · 2020. 8. 29. · 1.5 Wavelength À, 2.5 Figure 2.2 (a) Scheme of an X ray tube. (b) Intensity](https://reader033.vdocuments.mx/reader033/viewer/2022060911/60a5e38ba1633e77fd751f94/html5/thumbnails/6.jpg)
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frequency (Hz) or energy (eV or keV)
![Page 7: Spectrum - Pusan National Universitybml.pusan.ac.kr/.../IntroMedEng/2020/03_Spectrum.pdf · 2020. 8. 29. · 1.5 Wavelength À, 2.5 Figure 2.2 (a) Scheme of an X ray tube. (b) Intensity](https://reader033.vdocuments.mx/reader033/viewer/2022060911/60a5e38ba1633e77fd751f94/html5/thumbnails/7.jpg)
X‐ray spectrum as a function of energy
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![Page 8: Spectrum - Pusan National Universitybml.pusan.ac.kr/.../IntroMedEng/2020/03_Spectrum.pdf · 2020. 8. 29. · 1.5 Wavelength À, 2.5 Figure 2.2 (a) Scheme of an X ray tube. (b) Intensity](https://reader033.vdocuments.mx/reader033/viewer/2022060911/60a5e38ba1633e77fd751f94/html5/thumbnails/8.jpg)
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![Page 9: Spectrum - Pusan National Universitybml.pusan.ac.kr/.../IntroMedEng/2020/03_Spectrum.pdf · 2020. 8. 29. · 1.5 Wavelength À, 2.5 Figure 2.2 (a) Scheme of an X ray tube. (b) Intensity](https://reader033.vdocuments.mx/reader033/viewer/2022060911/60a5e38ba1633e77fd751f94/html5/thumbnails/9.jpg)
Wrap‐up
• wavelength vs. frequency• photon• kV vs. keV• ionizing radiation• spectrum
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