What kinds of transitions produce x-rays?

2. What kinds of transitions produce x-rays?

3. An x-ray tube: motor rotates tungsten to prevent over- heating

4. X-rays are produced 2 ways in an x-ray tube: x-rays • Electron from • cathode knocks • an inner e- out, • and an outer e- • falls down to the • empty orbital, • emitting an x-ray. 2. Electron ricochets around nucleus. As it decelerates, x-rays are emitted.

5. CAT (or CT) scans – Computed Axial Tomography As the x-ray source and detector rotate, a 3-D picture is built up x-ray detector x-ray source As the patient moves through, many slices are taken….

6. getting a CAT scan… brain CT scans

7. The idea behind particle accelerators (atom smashers): ________ particles + high __________: old energy _______ particles because ________ new E = mc2 The more the ________________ given to the old particles, the more _________________ of the new ones by E = ______. energy the mass mc2

8. Ex: Early particle accelerators used _______________ generators: van derGraff voltage V • high _______________ • work done on a charge q: W= • high _______________ • work done on a charge q: W = qV Ex: How much KE will a proton gain when it is accelerated through a potential difference of 300,000 V? = DKE W = qV v ~ 7.6 x 106 m/s crosses the Earth in 1.7 s, but still only 2.5% of c W = (1 e)(300,000 V) W = 300,000 eV

9. Ex: An example of a modern particle accelerator is the_____________________ . cyclotron. v v v The _______________ field accelerates the particle. The ______________ field is ____________________ to v, so it only causes the particle to ___________________________ . electric magnetic perpendicular turn in a circle

10. the very first cyclotron world’s biggest cyclotron a 1939 cyclotron

11. The particle accelerator at Cornell University accelerator storage ring for positrons

12. SLAC – The Stanford Linear Accelerator Center

14. Fermilab in Chicago – another accelerator built in the shape of a circle.

15. Find the ladder for scale. …inside Fermilab

16. One of the largest – at CERN - Angels and Demons

17. A detector at CERN led to the discovery of the W and Z particles – carriers of the weak force

18. As accelerators with higher and higher _____________ were built, particles with bigger and bigger ____________were discovered. energy masses There seemed to be no _____________ to the________________ of newly discovered particles. pattern hundreds _____________________ _____________________ tracks of subatomic particles Finally, the _________________________ was worked out in the _______________ . It explained how all of the particles are made of ________________ fundamental particles and their _________________________ .

20. Decay of a K+ meson in a bubble chamber:

22. cloud chambers: use supersaturated gases

23. Bubble chamber: 1 Fill a large cylinder with a liquid heated to just below its boiling point. 2. As particles enter the chamber, a piston suddenly decreases its pressure, and the liquid becomes superheated. 3. Charged particles create an ionization track, around which the liquid vaporizes, forming microscopic bubbles.

24. Ye Olde Bubble Chamber from Fermilab (Chicago)

25. bubble chamber tracks

26. As accelerators with higher and higher _____________ were built, particles with bigger and bigger ____________were discovered. energy masses There seemed to be no _____________ to the________________ of newly discovered particles. pattern hundreds _____________________ _____________________ tracks of subatomic particles Standard Model Finally, the _________________________ was worked out in the _______________ . It explained how all of the particles are made of ________________ fundamental particles and their _________________________ . 1960s twelve antiparticles

27. _______ _______ The Standard Model: All matter (or antimatter) is made up of ___________or combinations of____________. leptons quarks • Other 12’s: • a dozen • Jupiter’s period • months in year • hours in day • inches in foot • disciples • yrs. of youth • teenage elves quarks leptons Let’s look at leptons first. read the fine print __________________

29. increasing____________________ only found at high energies (high temps.) everyday low-energy leptons mass/energy Neutrinos have _______ _____ mass. almost no • Lepton means________________________ • Leptons all have charge _______or__________________ • Their antiparticles are charged __________________ • They occur____________________—they do not • ___________________________________________. “light weight.” -1e 0 (neutral). +1e or 0. by themselves combine to form bigger particles

30. increasing __________________ only found at high energies (high temps.) everyday, low-energy quarks mass/energy • Quarks all have charge _________or ___________ • Their antiparticles are charged _________ or_________ • They ___________________by themselves because you • cannot have a particle with a_________________________. • They occur in groups of _____________________ (-1/3)e. (+2/3)e (+1/3)e (-2/3)e never occur non-integer charge 2’s or 3’s.

31. q q q q q particles made from ___________ quarks “mes-” means _________ masses “bary-” means _______ masses middle heavy qqq Must be all __________ or all_____________ or matter antimatter

32. Ex. A certain particle is made up of 3 quarks: 2 ________ quarks and 1 _____________ quark. u d u up down What is the total charge of the particle? Add up the charges: u: (+2/3) e u: (+2/3) e [(+2/3) + (+2/3) + (-1/3)] e d: (-1/3) e = 1 e Is this a baryon, a meson or a lepton? 3 quarks  a baryon proton. This particle is also known as a________________

34. d d Ex. A certain particle is made up of 2 quarks: 1 ____ quark and 1 __________ quark. u antidown up What is the total charge of the particle? Add up the charges: (+2/3) e u: [(+2/3) + (+1/3)] e : (+1/3) e = 1 e Is this a baryon, a meson or a lepton? 2 quarks  a meson p+ (positive pion). This particle is also known as a ______________________

35. Ex. A certain particle is made up of 3 quarks: 1 _____ quark and 2 ________ quarks. d up down d u What is the total charge of the particle? u: (+2/3) e Add up the charges: d: (-1/3) e [(+2/3) + (-1/3) + (-1/3)] e d: (-1/3) e = 0 e Is this a baryon, a meson or a lepton? 3 quarks  a baryon neutron. This particle is also known as a_____________________

36. Ex. A certain particle is made up of 3 quarks: 2 ________________ quarks and 1 _________________ quark. u u u u d d d : u : u : u u u u u u d d d antiup antidown What is the total charge of the particle? (-2/3) e Add up the charges: [(-2/3) + (-2/3) + (+1/3)] e (-2/3) e = -1 e (+1/3) e u u Compare this one: to: d antiproton The left-hand particle is an _______________________ . It is an example of ___________________ . It has the __________ mass as the proton, but the _________________ charge. same antimatter opposite

38. s s u u u b d d d Determine the charge and type of each particle. a whole number of e's The total charge must be ____________________________

39. What is matter made up of? neutron or a proton

40. Forces The Fundamental __________________ of Nature:

41. Ex: How can gravity hold Earth to the Sun if it is the weakest force? • Earth and Sun have a lot of ______________ • Earth and Sun are _________________ , so the • __________________________ force is not important. • 3. Earth and Sun are_______________ , so the • ________________________ forces are not important. mass. neutral electromagnetic far apart two nuclear Ex: The total amount of mass-energy in the universe is: ordinary matter: ______% (baryons and leptons) dark matter: ______% (unknown) dark energy: ______% (unknown) 5 23 72

42. Total after Conservation Laws: Total before =________________ Charge q 1. _____________________ is always conserved. q1 + q2 + … q1’ + q2’ + … = momentum (p) • In the absence of_______________ , ________________ • is always conserved. friction = p1’ + p2’ + … p1 + p2 + … 3. In the absence of________________, ________________ is always conserved. energy (E) friction Modern physics: Classical physics: ET ET’ mass-E mass’-E’ = = = using E = mc2 KE + PE KE’ + PE’