X-RAY RADIATION Constants Units of Energy h = 6.626 - 10-3“ J•sec Planck constant e = 1.6- 10-19 C charge of electron e = 3- 10" m/sec speed of light m = 9.11. 10- kg mass of electron 1 ev = 1,602-10-" J 1 kev = 1,602-10-"J 1. Relationship between X-ray frequency and wavelength: K-cathode A- anode here A is wavelength (m), f is frequency (Hz), e is speed of light (m/sec). Х-гауs clectrons 2. Energy of X-rays photon: E = hfmaz = Amin is minimum wavelength of X-ray radiation (m), fmar is maximum frequency of X-ray radiation (Hz), h is Planck constant (I 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: my? ela = and then the kinetic energy of electron motion is transferred into energy of X-ray photons: - = hfmar fmax is maximum frequency of X-ray radiation (Hz), h is Planck constant I sec), c is speed of light propagation in vacuum (m/sec), e is charge of electron (C), m mass of electron (kg), U, is potential difference or voltage between cathode and anode (V), v is speed of clectrons motion (m/sec). 4. Relationship between wavelenth of X-ray radintion and Voltage on the tube: 1.23 Amin (nm) = Da(kv) U, is potential difference or voltage between cathode and anode (V), 2min is minimum wavelength of X-ray radiation (m). 5. Linear attenuation coefficient (I/m): H= k-p-2.2', k = 10-° is coefficient of proportionality (W/VA), p is density of the material (kg/m'), Z is atomic number of the material, i is wavelength of X-ray radiation (m). 6. Mass attenuation coefficient (m'kg): H. =-= kza H is linear attemuation coefficient, k= 10-° is coefficient of proportionality (W/V-A), p is density of the material (kg/m), Z is atomic number of the material, i is wavelength of X-ray radiation (m). 7. Attenuation of X-ray radiation intensity: I = lbe "Hd here I, is the initial intensity of X-rays (W/m); / is the intensity of X-rays after passing a material of (1/m) 8. Half value layer. HVL =- In(2) 0,693 u is lincar attenuation coefficient (1/m).