General Science Review: X-Ray Production in the Tube

1. RTEC A - WEEK 4GENERAL SCIENCE REVIEW&X-RAY PRODUCTION IN THE TUBE ***FINAL***

2. ALERT Please do not print the lecture until you see “FINAL” on the first slide.

3. Objectives • General Science review • Atomic interactions in the tube

4. _________ of the atom. Electrons orbit around a nucleus (center) Atomic Models

5. ATOM

6. Differences in Binding Energy

7. K L M Shells

8. Electrostatic Laws • ___________________________ • Like charges ________ • Unlike charges ________ • Inverse square relationship • Electrostatic force is very strong when objects are _______________ • It decreases rapidly as objects _________

9. How “X-rays” are created TO PRODUCE X-RAYS YOU NEED: • _____________________________ • ____________________________ • _____________________________

10. How “X-rays” are created • Power is sent to x-ray tube via cables • ______________is sent to filament on cathode side. • Filament heats up – electrons “boil off” • Thermionic ____________ • Negative charge

11. How “X-rays” are created • Positive _________ is applied to ANODE • _______________attracted across the tube to the positive ANODE. • Electrons “slam into” anode – suddenly stopped. • X-RAY _______________ ARE CREATED

12. Electromagnetic Energy Spectrum • Spectrum • Continuous range of energy • Although there are precise ranges defined, they often overlap • 3 most important to Radiologic technology: • __________ • __________ • __________

13. Electromagnetic Radiation • _________is the smallest quantity of any type of EM radiation • It is a small bundle of energy traveling at the_____________ • Only visible light is naturally apparent to us • May be described as wavelike fluctuations of___________________

14. Electromagnetic Radiation • These bundles of electric and magnetic fields travel at the same velocity: • Travel at the speed of light • _______________________________ • The Photons of EM radiation differ only in __________and ______________

15. General Characteristics of EMSX-ray photons: • Have no ______ or _________ form • Travel in a ________________ path (until interaction occurs) • Dual nature: wave vs. particle • _____________ by • electric or magnetic fields • gravity

16. Wavelength • Wavelength is the difference between: • ___________to ___________ • ___________ to ___________

17. Frequency • Frequency is the ________of wavelengths passing a _____of observation per second

18. Wavelength and Frequency • Wavelength & frequency are inversely proportional • As Wavelength ________ frequency ___________ • As wavelength _________ frequency ___________ • Frequency and wavelength are closely associated with the relative energy of electromagnetic radiations. • More energetic radiations have _________ wavelengths and ________frequency.

19. The shorter the wavelength – the higher the frequency

21. The Electromagnetic Spectrum • X-rays have wavelengths much shorter than visible light, but longer than high energy gamma rays.

22. What is Ionization?

23. When an electron is _______ or _________ from the atom- it is ionized

24. Kinetic energy • Energy of __________ • The electrons KINETIC energy is converted to electromagnetic or PHOTON energy

25. X-ray production begins at the atomic levelEnergy (photons) are released when the electron collides with another electron,or passes close to the nucleus of the atom –the change in energy of the shells –produces photons

26. X-ray Production in the TUBE

27. INTERACTIONS IN THE TUBE • ________________________ • ________________________ • ________________________

28. Tube Interactions • Heat = 99% • X-ray = 1% • Bremsstrahlung (Brems) = 80% • Characteristic = 20%

29. Bremsstrahlung Radiation • Heat & Characteristic produces EM energy by e- interacting with tungsten atoms e- of the target material • Bremsstrahlung is produced by e- passing by closely with the nucleus of a target tungsten atom – the change in direction of the electron – releases a photon of energy

30. Heat • Most kinetic energy of projectile e- is converted into heat – 99% • Projectile e- interact with the outer-shell e- of the target atoms but do not transfer enough energy to the outer-shell e- to ionize

31. Heat

32. 8 p+ + 8e- = neutral atom • Projectile electrons from cathode • Pass by the electrons in the target • Causing the electrons to vibrate (excitation) • Excitation produces small amounts of heat HEAT e e

33. Heat is an excitationrather than an ionization

34. Bremsstrahlung German word meaning slowed-down or braking radiation

37. Bremsstrahlung Radiation

38. Creates a polychromatic spectrum – x-rays of different energies X-ray Photons – BREMS 38

39. Energy (photons) are released when the e passes close to the nucleus, then changes direction

40. Electron Passes by nucleus Changes direction Energy released as a PHOTON BREMS RADIATION

41. Brem’s Radiation Animation • http://www.coursewareobjects.com/objects/mrophysics_v1/mod08/0816a.htm

42. Characteristic Radiation • Projectile e- with high enough energy to totally remove an inner-shell electron of the tungsten target • All tube interactions result in a loss of kinetic energy from the projectile e- • Characteristic x-rays are produced when outer-shell e- fills an inner-shell void

43. Characteristic Radiation (Tube)

44. Electron hits ________ e in orbit – knocked out & creates a hole Other E’s want to jump in ________ released as PHOTONS CHARACTERISTIC (in tube)

45. It is called characteristic because it is characteristic of the target element in the energy of the photon produced

46. Characteristic Radiation Animation • http://www.coursewareobjects.com/objects/mrophysics_v1/mod08/0808a.htm

47. Tungsten Atom