1
??? ?????????

• 2-1 ????????????
• 2-2 ??????????
• 2-3 ???????????
• 2-4 ????????????

2
2-1 ????????????

• ?????????,????????????????????????????
• ??????,?????,???????(???????????)?
• ???????????
• ??????p?e???????
• ????x??????
• ????n??0??0???

3
???????????????

• 1. ?????
• ???????????????????????????,??????????????????????
  ???????,??????????????????????????????????????????
  ???????,???????,?????????,??????X????????
• ?????????,?????????????????,??????????????????????
  ????????,??????,???????????,?????????,????????????
  ????

4

• ????

?????????????

• ????????-??????????
• ?????
• ????????????????

???,2?me/m0ltlt1,?meltm0,??? ?????,????,???????????,
??????,Ekin? E,pc ? E ????,
???,
5
2. ???????????

• ???????????????????,?????????,?????????????
• ??????????????????????????????????????????????????
  ????????,? ???
• ?,?????????????????,???????????????????,??
  ??????????????

6
Bethe-Bloch formula
Energy transfer I ? dE ? Tmax , I mean
excitation potential II0Z, I010eV Relativistic
rise ln ?2 term Relativistic rise cancelled at
high ? by density effect. Parametrized by ? ?
Fermi plateau
7
Interaction of charge particles
Particles can only be detected if they deposit
energy in matter. How do they lose energy in
matter?
classical
8
???????
??????????Bethe-Bloch??
???,?????????? ??dx???g/cm2, ???????
??????(??g/cm3),ds???(??cm)? ???????????????????
?????? ????
9

• ???????
• ?????x????,????????????
• ????????,??????????????????,??????????,????????
  ???,??????????,??????????????????

10
????
?????
????
j0.2,?(K/2)z2(Z/A)(x/ß2)MeV,x??g/cm2
???????????????
?????????????
11
???

• ?????????????????????????????????,????????????????
  ???????
• d?????????,??????
• ?? ,??????
• ?TltltTmax?,F??????????????,????1??????????????,???F
  ??????,?????????(F?0),??F????????????
• ??????????????????,???????????????,
  ??x???
• ?????????????????,??????????

12
? 50MeV???,???1/3, ???1g.cm-2????,????????????
?1GeV?????10g.cm-2????,?????? ???????
???????????,????????????????, ????????????????????
???????
??????
13
??????Bethe-Bloch????????????????
???????,???????????????????
14

• ??
• 1)???????????,????????????????????????????????????
  ???
• 2)?????????????z2????
• 3)???????????,?
  ??,?????????????,???????????
• 4)?????????,??????????????????,??????????????
  (????????)?,??????????????
  ?????
• 5)? ,Bethe-Bloch???????
  ?????????,???????????

15

• 6)???????????,????????,???1,??????????????????????
  ??????????3-4??,?????????????????????????????????
  ???????????????,????????????????????(Minimum
  Ionizing Particles?MIP)?
• 7)???gt4?,???????????,????????
• 8)????????,?????????????????,????????,????????????
  ??,??????
• 9)????????,????????????????

16
??????????????????

• ?????????????????????????(10-8cm)?,???????????,???
  ?????,???????????
• Rutherford????
• ?????????????????????????????????????????????
  ???,????????????????????????????

17

• ????????????Molliere?????????????????????????,????
  ???Rutherford???

18

• ????
• 
  
• ?????,
• ???????,??????????????????????????????

P??????, ??MeV/cX0???????, x/X0??????????????
19
?? ????(Bremsstrahlung)

• ??????????????????????????10-8cm?,??????10-13cm?
  ?,????????????,??????,??????,??????????
• ????????
• ??????
• ?????????
• Egtgtmec2/aZ1/3

20

• ????X0
• ?
• ?????E0????????x(g.cm-2)??????????
• ?????xX0?,???????????????????????1/e,?X0?????????
  
• ????????????,?
• Xi?i????????,wi?i????????,??????

????
21

• ????Ec???????????????????????Rossi??????????????
  ??????????????????
• ?????
  EgtEc,????????
• 
  EltEc,??????
• ????????????????M2???
• ?????????????,????????,????,?????,???????????
  ??????????????????? ??
• ?????????????????Z2???
• ??????????????????,??Z????,??????????????????
  ?
• ???????? ????

22
????????
23
????????????????
?? X0(g.cm-2) Ec (MeV)
H2 63 350
Al 24 40
Ar 20 35
Fe 13.8 20.7
Pb 6.4 7.4
???SF3 9.6 13
Plexiglass 40.5 88
H2O 36.1 83
???NaI(Tl) 9.5 12.5
???BGO 8.0 7
24
????????Cherenkov radiation

• ?????????????????????,???????????????vgtc/n????????
  ????
• ??????????????????
• ?????????,??????????
• ????
• (1)???????????,?
• (2)???????
• (3)?? ????????????
• ???????????,??????

25
?????????

• (1)???????
• (2)???
• (3)???
• (4)?????
• (5)???????

26
?? ????

• ?????????????????????????????????????
• ???????????,???????????????????????????,??????????
  ???????,???X?????
• ???????????????
• ???????????????????
• ??????
• ?????????X???

27

• ??????????
• EP?????????,E?????????
• ??????,???????
• ????,????E/m????????????????????????
• ????????,???????????

28
??????(Syncrotron Radiation)

• ?????????????????????????????????
• ?????????????????????,???????????????????
• ???????????????????????????????????????

29

• ???????,????????
• ????????
• ???????????,????????????,?????
• ???????????,??????
• (1)???
• (2)????
• (3)??????

30
?????????????

• ?????????????????????????,?R???
• ??????????????????????????
• ??????????????????????????????????????,?R0???
• ??????????????????X????????, ?R?????
• ????Rm??R,??g/cm2, ???????

31

• ????????????????????????
• ???????????

?????
32

• ??????????????????????????????
• ?????

33

• ?????????(????)
• ????????
• ??
• ???
• ????????????,???
• ??(0.5MeVE5MeV)??????

34

• ???????
• ???1TeV??????????265m?
• ????10GeV??????(Z11,A22)????

35
(No Transcript)
36
(No Transcript)
37
??

• ?????????????????????????????????,????????????,???
  ?????????????????
• ???????????????????????????????????????????,??????
  
• (1)???????????????????????????,???????????????????
  ????????????????,??????????????????????????

38

• (2)????????,????????????????????????,???????????,?
  ???????????????????????????
• (3)????????????????,???????????????????????
• (4)????????????,????????
• (5)????????????,????????
• ??????????????,??????????????????

39
2-2 ???????????

• ???????????????????????Compton-Wu????????????????
  ????????,?????????
• ?????????????????????
  
• 
  I0????????,???? ????
• 
  ???????,x??????
• ???/?,t?x ????,
• ? ??????????
• ?????????,?

40

• ??????????????????????,???????
• ??
• ??????????????????????????,????(b)
  1b10-24cm2
• ?????????????????????????

???????(s-1 cm-2)
??????(cm-2)
?????(s-1 cm-2)
?i??i????????, A????, NA????????
41
??????

• ?????????????????????????
• ?????
• hv????????,Ei??i????????
• ??????????X????????

42
X???

X?????
X???
43

• ??????????????????
• 1)???????????????
• 2)??????????????
• 3)???????????????,????????????????????.

44
?????-?????
????????????, ?????????????
Compton wavelength
45
???????

• ??????
• ??????

46

• ???????????

47
Compton wavelength

• Compton-Wu???????

??Z??????,?????
48
Compton-Wu????????
49
???????

• ????? ??????????,????????2??????????1.02MeV?,????
  ??????,???????????,??????????????????
• ???????????????????????????????,??????????????0-2m
  ec2????,??????????????????,?????????????

50

• ??????????

51

• ????? ???????????????????????????????????????????
  ???????????????????????????????
• ?????,?????????????0,???????????????????????
• ???????????0,
• ????????????0 ?
• ????????

52
??

• ????????????????????????,?????????????????????????
  ?????,???????
• ??????????
• ??????????????????????
• ???????????????????????
• ????????????????????????

53

• ??????,?????????????????????????????,?????????????
  ????????????
• ???????????????????????,??????????Z????????????

54
??X (?)?????
????????,?????????????????????,???????????
55

• ???????
• ????

56
2-3 ???????????
???????

• ?????????????????????????
• ???GeV?????-????????????50mb?1mb10-27cm2
• ?????????,??????????????????p52 ?2.3.1
• ??????I
• ??????T

57

• ?????????,???????????????
• ??????????????,?????????????????????,???????????
• Z?6??????????????????????X0
• ???????????
• ??N????????????,????????????????????
• ?g-1cm2?NNA
• ????????A,? ?g-1cm2?ANA/A

58
?????????????

• ????????????????????????,?????????????????????????
  ???????
• ?????,????????,?????????????
• ????????????????????????
• ??????????????????

59
1?????

• ???????????????????????????????,????????,?????????
  ????????,????????????,???????????????,????????????
  ?????,???????
• ?????????????
• ??????,?Enlt30MeV???,????????

M????? ????
60

• ?????????,?mn1, MA
• ????,???????????????0,
• A1?,E??En,???
• ????? ??????????,?????????????????????????????
  ???
• ?????????????????????????????,????????????????
• ??????????????????, E?????En?????????????????10??
  ????,??????????????,???????????????????

61
2?????

• ???????????????????????????????
• ????????????????????????????????????????
• ???????????
• a(????)A(??)?b(????)B(???)Q
• ???? A(a,b)B
• ???????????,?????????Z?????A??????????????(?
  ????????)??,??????
• Q?gt0???,???? Q?lt0???,?????

62

• ????????????
• ??????,??????????????????0?????????,????

???????239Pu???????
63

• p56-57 ?2.3.2????????????????

• ????????
  ??????????????,?????BF3??,????????????????10B
  ????,??????? 10B ???????

64
3?????

• ?????????????????????????????????
• ??????????????????
• ?????????235U(?528b),239Pu (?743b) ,233U
  (?531b)??????????,???200 MeV,?????????170MeV?????
  ?????????,???????????,?????????
• ??????????????,????????????,?????????????
• ?????????????????????????????????????????????????,
  ????????????

65
????????????
???? ???????(mb) ?? (MeV) 3MeV?????(mb) ???(y)
232Th 231Pa 234U 236U 238U 237Np 209Bi lt0.2 10 lt0.6 - lt0.5 19 1.75 0.5 0.4 0.8 1.45 0.75 50 0.19 1.1 1.5 0.85 0.55 1.5 1.411010 3.281010 2.45105 2.34107 4.47109 2.14106
66
4????

• ??????????,???????,??????????????,????????????????
  ????????????,??????????????????,?????
• ??115In?????,??????,
• ????????????, 116In???????,
• ??????????????,??????????
• ????????,?????????????????????????????

67

• ????????????????????????????????????????
• ?????????
• ???????,????????1cm2????????
  
• 
  ????????????,d??
• 
  N????1cm3?????,ƒ????
• ??????,?????????????,????????????????????????
  ?????????????????,????????????????????????????????
  ??????,???????????????1cm2??????????As,????????
• 
  

68
2-4 ????????????

• ??????????,?????????,????????????????????????????
  ???????????????
• ????
• ????
• ????

Electron shower in a cloud chamber with lead
absorbers
69
??????

• ???????????????,??????,?????????????,
  ????????????,????????????,????????-
  ???-???????,?????????????????????????,???????????,
  ?????? ??????????,???????????????,???????????????,
  ????????????????,????????

70

• ????Ec
• E gt Ec?,???????????
• E lt Ec?,???????????
• ????????
• Monte-Carlo?????CERN?GEANT4?????????

???
71
Electromagnetic Shower
Energy loss by Bremsstrahlung (charge particles)
Effect plays a role only for e and
ultra-relativistic µ (gt1000 GeV)
????Xo??????????????,????? ????????1/e???????????
? ???
72

• ????????????????????amma????
• ???????
• ?????????
• ????(Moliere)??????
• ?????

73
??????( Hadron Shower)
????????,?????????????,????????,????????????,?????
?????????? ??????????????????,????????????,??????
???????
74
Hadronic cascades
Various processes involved. Much more complex
than electromagnetic cascades.
75
Hadron Shower
The interaction of energetic hadrons (charged or
neutral) with matter is determined by inelastic
nuclear processes.
Excitation and finally break-up of nucleus?
nucleus fragments production of secondary
particles.
Hadronic absorption length
Hadronic interaction length

• neutron induced fission En Eth 1/40 eV
• inelastic reactions hadronic cascades
• En gt 1 GeV

76
Material Z A X0(cm) ?I(cm) Lead
82 207 0.56 17.1 Copper 29 63.5
1.44 15.1 Iron 26 56 1.77
16.8 Silicon 14 28 9.4 45.5 Al
13 27 8.9 39.4 C
6 12 19 38.1 He(gas) 2
4 5.3E5 3.6E5