X-RAY RADIATION Constants Units of Energy h = 6.626 · 10-34 J.sec Planck constant 1 eV = 1,602-10-19 J e = 1.6 · 10-19 C charge of electron c = 3· 10® m/sec speed of light m = 9.11 · 10-31 kg mass of electron 1 keV = 1,602.10-16 J 1. Relationship between X-ray frequency and wavelength: K - cathode A - anode c = f1 here A is wavelength (m), ƒ is frequency (Hz), c is speed of light (m/sec). X-гаys electrons 2. Energy of X-rays photon: hc E = hfmax = Amin Amin is minimum wavelength of X-ray radiation (m), fmax is maximum frequency of X-ray radiation (Hz), h is Planck constant (J·sec), c is speed of light propagation in vacuum (m/sec). 3. In the X-ray tube, firstly, the energy of electric field is transformed into the kinetic energy of electron motion: ту? eUa 2 and then the kinetic energy of electron motion is transferred into energy of X-ray photons: mv? = hfmax 2 fmax is maximum frequency of X-ray radiation (Hz), h is Planck constant (J·sec), c is speed of light propagation in vacuum (m/sec), e is charge of electron (C), m mass of electron (kg), Ua is potential difference or voltage between cathode and anode (V), v is speed of electrons motion (m/sec). 4. Relationship between wavelenth of X-ray radiation and Voltage on the tube: 1.23 Amin (пт) Ua(kV) U, is potential difference or voltage between cathode and anode (V), Amin is minimum wavelength of X-ray radiation (m). 5. Linear attenuation coefficient (1/m): µ = k•p• 2³ •Z³, k = 10-9 is coefficient of proportionality (W/V²A),p is density of the material (kg/m³), Z is atomic number of the material, 2 is wavelength of X-ray radiation (m). 6. Mass attenuation coefficient (m²/kg): =" = ka³Z3 и µ is linear attenuation coefficient, k= 10-9 is coefficient of proportionality (W/V²A), p is density of the material (kg/m³), Z is atomic number of the material, 2 is wavelength of X-ray radiation (m). 7. Attenuation of X-ray radiation intensity: I = I̟e-µd here I, is the initial intensity of X-rays (W/m²); I is the intensity of X-rays after passing a material of thickness d (W/m²), d is thickness of the adsorbing layer (m), µ is linear attenuation coefficient (1/m). 8. Half value layer: In(2)_ 0,693 HVL = и и u is linear attenuation coefficient (1/m).