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TRNG I HC KHOA HC T NHINTRNG I HC KHOA HC T NHINKHOA VT LKHOA VT L
B MN VT L NG DNGB MN VT L NG DNG
HVTH:HVTH:Nguyn ng KhoaNguyn ng KhoaL Th LaL Th LaL Ngc Thy TinL Ngc Thy TinTrn Th M HnhTrn Th M Hnh
Nguyn Thanh TNguyn Thanh T
GVHDGVHD:: PGS. TS. L Vn HiuPGS. TS. L Vn Hiu
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a ch bn ti:http://mientayvn.com/Cao%20hoc%20quang%20dien%20tu/Semina%20tren%20lop/semin
Ni bn c th tho lun:http://myyagy.com/mientay/
Dch ti liu trc tuyn min ph:http://mientayvn.com/dich_tieng_anh_chuyen_nghanh.html
D n dch hc liu m:http://mientayvn.com/OCW/MIT/Co.html
Lin h vi ngi qun l trang web:Yahoo: [email protected]: [email protected]
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LCH S PHT TRIN VL PLASMA
1845:t Plasma c pht biu vi ngha sinh vt hc
1923: Langmuirv Tonks gi cht kh
trng thi dn in l plasma
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1667,nh bc hc Floreltre pht hin rangn la n c tnh dn in.
1698,tin sVolt ngi Anh pht hin hintng phng tia la in trong khng khkhi nghin cu s nhim in ca hphch
u th k XIX,gio s Ptro pht minhra h quang
LCH S PHT TRIN VL PLASMA
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Irving Langmuir (1881 -1957) l nhkhoa hc M u tin nghin cuv trng thi plasma, ngi ccoi l cha ca vt l plasma.
Nm 1920, Langmuir m t th nghimto ra khi cu pht sng c ctnh dng nh ging st hn.
Nm 1924, ng a ra khi nim nhit in t v pht minh ra phngphp chn on mt v nhit plasma bng u d in.
LCH S PHT TRIN VL PLASMA
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Nm 1940, HannesAlfvn chngminh rng mt loichuyn ng tp th
mi, gi l sng t-thy ng lc hc cth c sinh ratrong cc h plasma.
Cc sng ny ngmt vai tr quantrng xc nh tnhcht ca plasma.
LCH S PHT TRIN VL PLASMA
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KHI NIM PLASMA
Theo nh ngha ca Langmuir, plasma l mttp hp cc ht mang in v cc ht trungha phi tha mn:
1. iu kin gn trung ha:
2. Bn knh Debye phi nhiu ln nh hn kchthc ca min cha tp hp :
, ,0
e i e iZ n }
Dr L=
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Mt s dng Plasma
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TNG QUAN V CHN ON PLASMA
Chn on plasma l nghin cu cc hin tng vt l tintrin bn trong plasma, t suy ra cc tnh cht caplasma.
Phng php chn on plasma l cc phng php onhit , mt , thnh phn plasma.
Kh khn trong vic thit lp m hnh l thuyt
Phi tin hnh chn on bng nhiu phng php khcnhau trn cng mt i tng
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V d chn on plasma trong tokamak
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Chn onChn on Thng s plasmaThng s plasmau d langmuir Nhit plasma, nng , th plasma ..
Phn tch quang ph pht x nhit , nng , thnh phn plasma
Chn on chm ntron nhit ion
Giao thoa k viba nng electron
Quay phim tc cao hnh nh plasma
Tn x thomson Nng v nhit electron
Tn x chm laser
. ..
Cc phng php chn onCc phng php chn on
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u d t
Tn xThomson
u dLangmuir
Phn tch quangph pht x
Giao thoa kMicrowaves
Phn tch nnglng ion
Quay phimtc cao
Sng v tuyn
Plasma
Cc phng php chn onCc phng php chn on
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plasma
Voltage GeneratorV
I
wire
insulator
u d tnh in Langmuir
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L mt si dy kimloi mnh hnh tr,bn ngoi c
bao bc bi chtcch in dc theochiu di, ch hmi nhn ca si
dy gi l u d.Kch thc u dvo c vi mm nvi cm.
Lp in miLp in mi
Thp khng gThp khng g
Cu to u d LangmuirCu to u d Langmuir
Si dy kim loiSi dy kim loi
mnh lm bngmnh lm bngTungsten hay Modylen,Tungsten hay Modylen,
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iu chnh bin triu chnh bin tr U Uanodeanode--u du d thay ithay i I I
u du dthay ithay i
Ampe k v Vn k xcAmpe k v Vn k xcnh s ph thuc ca Inh s ph thuc ca Iu du dvo Uvo Uanodeanode--u du d Cc c trng ca plasma Cc c trng ca plasma
(n(nee, T, Tee))
S mc mch
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S hnh thnh th ni v th plasma Khi a u d vo trong
plasma, xung quanh ud hnh thnh mn chntnh in, xung quanh ud hnh thnh mt intrng
in trng ny ngn ccelectron i n gn ud
Sau mt thi gian s xyra s cn bng, th khicn bng gi l th ni: Vf
Lc ny trong plasmacng cn bng v c thgi l th plasma: Vp
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Tin hnh thay i th u d
Khi th u d V> Vp: cc ion dng n ud s b y tr li mi trng plasma ng thicc electron b ht vo u d,
Khi th u d V< Vp: th ngc li, cc iondng b ht vo u d trong khi ccelectron b y ra xa u d.
Khi th u d V = Vf khi dng tng cng quau d bng khng t
Vy dng qua u d c th l dng m hocdng dng l ty thuc vo hiu th plasma Vpvi u d V,
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Mt dng electron n u d
1
2
0exp
2
pee
e e
e V Vm J n e
kT kT T !
01
2
e
i
i
kT J enM
!
Mt dng ion n u d
cng dng tng cng m u d thu c:cng dng tng cng m u d thu c:
e i I AJ AJ !
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Cng dng in qua u dCng dng in qua u d
Trong :Trong :
A ltit din ca u dA ltit din ca u d
MMii: khi lng ion trongplasma: khi lng ion trongplasmamme:e: khi lng electronkhi lng electron
nno:o: nng electron hay ionnng electron hay ion
1
2
0
211 exp
2
pi
B
e e
e V VM I A en v
m kTT
!
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ng c trng Voltng c trng Volt -- AmpereAmpere
Min A:Min A: Khi th u d ln hn th plasma V>Khi th u d ln hn th plasma V> VpVp: cc ion: cc iondng n u d s b y trli mi trng plasma ngdng n u d s b y trli mi trng plasma ngthi cc electron b ht vo u d, u d c th thay th chothi cc electron b ht vo u d, u d c th thay th choanode ht cc dng in tch.anode ht cc dng in tch.
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ng c trng Voltng c trng Volt -- AmpereAmpere
1 1
2 2
0 0 81. exp2 4
p Pe ei e e
e e e
e V V
m kT I I A J An e eA nkT kT mT T
! ! !
Min B: Khi th u d V = Vp,
lc ny khng tn ti mn chin bao quanh u d.
B mt u d thu nhn dng ion velectron va chm vo n, nhngdng electron ln hn rt nhiudng ion nn n xp x bng:
1
2
0
81
4
e
p e
e
kT I I eA n
mT
} !
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Min C: V < VMin C: V < Vpp, u d, u d
bt u y cc e v ht ccbt u y cc e v ht ccion dng v pha u d.ion dng v pha u d.Ch c cc e no c ngCh c cc e no c ngnng mi ti c u d.nng mi ti c u d.
!
e
i
pfe
m
M
VV
e
kT
T
2ln
2Nhit e:
in th
Th plasma Vp
Th ni Vf
Khi V=Vf
e
pf
e
i
k
evenI exp
21
2
10
2
1
0
T
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Min D: V < VMin D: V < Vff , cc ion, cc iondng c chuyn ng ngudng c chuyn ng ngu
nhin xuyn qua vng mnnhin xuyn qua vng mnchn tnh in s b u dchn tnh in s b u dthu nhn, cng vi n lpthu nhn, cng vi n lpmn chn b mng i do thmn chn b mng i do th
ca u dca u d..
Nu V
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Xc nh cc c trng ca plasmaXc nh cc c trng ca plasmaNhit eNhit e
!
e
i
pfe
m
M
VV
e
kT
T2ln
2
Nng e hay ion dngNng e hay ion dng
2
1
02
!
e
e
pm
kTeAnI
T
2
10
2
!
e
e
p
m
kTeA
In
T
Vi Te xc nh trn,ta c th tnh c n0
Cng dng electronbo ha khi V=VP:
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U D PHT X(Emissive probe)
1. CU TRC
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Da trn nguyn l c bn l: Nu th u dl dng so vi th plasma, cc electronpht ra vi nng lng thp b ht tr li ud. Trong trng hp ny dng u d lkhng thay i bi s pht x ra ccelectron. Nu th u d l m so vi th
plasma, cc electron pht x c th i voplasma.
U D PHT X
2. Hot ng.
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Nu u d c nung nng cho n khi pht x raelectron, dng u d tng cng, l mt hm cain th u d, c cho bi cng thc:
Dng pht x:
( )p p i em e I V I I I !
* 2 expem em
B
e I A A T
k T
[[
[
J !
Vi Aem l din tch pht x ,
A* l hng s Richardson,T l nhit ca u d
l cng thot in t b mt u d.[J
U D PHT X
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U D PHT X
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o th plasma vi u d pht x ngi ta
dng 2 phng php chnh:Phng php th unPhng php th ni
Phng php o:
U D PHT X
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Phng php th un: Nguyn tc caphng php ny lda trn vic xc nh
trc tip th plasmat ng c trngu d pht x. Thm ti xut hinim un trn ng
c trng ca u dpht x tng ngvi th plasma.
U D PHT X
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Phng php th ni Phng php ny bao gm vic o cc th ni ca ud cc dng nhit khc nhau. Khi dng nhit tng ln,th ni ca u d s dch chuyn (tng) cho n khi nt gi tr bo ha ng vi th plasma.
U D PHT X
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Vpr
Ipr
Idis
3
1 2
Vdis
300- 00
-30-30
mch in u d trong plasma
U D PHT X
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U D FARADAY
(F
araday probe)u d Faraday l mt dng c o mt dng inCc loi u d:
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u d c hai b phn chnh:
* Vnh gp
* Vng bo v
U D FARADAY
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Vnh gp
Lm bng thp khng rc phun mt lp tungsten lmgim s pht x electron th cp t sbn ph ion
U D FARADAY
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Vng bo vDng che chnvnh gp khi cc
ion nng lngthp n t ngpha bn ngoivnh gp.
U D FARADAY
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Hot ng: Khi cc ion p vo b mt ca vnh gp,
cc electron cha trong phn kim loi ca
u d Faraday tun ra b mt u d trung ha cc ion tp trung trn b mt
Cc electron di chuyn to ra dng inu d, dng ny bng vi dng ion.
Mt dng c xc nh bi t s cadng ion v din tch ca vnh gp.
J= I/A
U D FARADAY
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Trong thc nghim: Ngi ta s dng vn k o in th u dV, sau mt dng s c tnh nh sau:
Vj =
Vi : R l in tr trong mchA l tit din u d
U D FARADAY
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U D FARADAY
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th th hin sph thuc ca mt dng vo v tr gc
U D FARADAY
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I. Nguyn tc kch thch ph phttrong plasma
Plasma, khi b nung nng n nhit khcao th tr thnh ngun bc x rt mnh.Cc dng va chm khc nhau gia ccht trong plasma l nguyn nhn gy ras pht x tia nng lng, v chnh ngthi sinh ra ph pht x.
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II. Cc qu trnh sinh ra cc phtx nng lng:
1. Bc x gin on
2. S bc x ti hp
3. S bc x hm
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1. Bc x gin on:
Cc nguyn t v cc ion caplasma b kch thch s bc xphoton
Quang ph bc x ca chng
l nhng quang ph vch. Ph vch l ph pht x ca
cc nguyn t ha hc hunh thng nm trong vngph t 190-1000nm (vngUVVIS). Ch c mt vi nguynt kim hay kim loi kim mic mt s vch ph nm ngoivng ny.
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2. S bc x ti hp:
S bc x ti hp sinh rakhi ion thu nhn in t.
S ti hp gia ion mv in t v vi ion
dng s lm gim ionm Trong qu trnh ti hp,
cc photon c bc xto ra quang ph lin tc.
Hnh nh ca ph mt tri
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2. S bc x ti hp:
S ti hp l qu trnh nghch ca qutrnh ion ho.
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3. S bc x hm:
Do s va chm gia cc in t vi ccion nng, in t b mt mt phn nnglng ca mnh, phn nng lng ny
pht x ra di dng lng t nh sng.Bc x sinh ra khi c s va chm cain t vi nguyn t hoc ion dngnng, gi l bc x hm.
Bc x hm s sinh ra quang ph lin tc
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III. Mi quan h gia cng , nhit , mt httrong plasma:
Trong plasma, nguyn t (Ao) ca mt nguyn t c kch thch ttrng thi nng lng thp Eo, ln trng thi nng lng cao Amc biu din theo phng trnh:
Ao +XE = A* (a) Sau mt thi gian,nguyn t b kch thch A* tr v trng thi c
mc nng lng thp hn s pht x ra lng t nng lng:
A* = hv +Ao (b)
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III. Mi quan h gia cng , nhit ,mt httrong plasma:
Nu gi Nm l s nguyn t ca nguyn t Ao b kch thch n trng thi nng lng cao Am,th theo quy lut Bolzamann ta c:
Nm= Na (gm/ g0) . exp ( -Emo/k T)
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Nu gi Ia l cng ca vch ph do qu trnh kchthch ph ni trn sinh ra,ng vi mt nhit plasma
nht nh ,Ia ph thuc vo:
- S nguyn t Ao b kch thchln trng thi A*, (Nm).
- Thi gian tn ti ca nguyn tA* trng thi kch thch, (tm).
- Nng lng kch thch nguynt A t trng thi c bn ntrng thi kch thch, (Em = h).
- Xc sut chuyn mc canguyn t A t trng thi kchthch nng lng Am v trngthi ban u nng lng Eo,(Amo).
Ia = f. (1/tm). Amo .Em. Nm I a = f. (l/t m) . A m0 .Na (gm/ g0).
h. exp ( -Emo/k T)
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ivimt loinguyn tv trong mt nhit plasma nht nh thcc yu t Amo, go, gm, Cm, hv l nhng hngs.
Ia ch ph thuc vo Na
Ia =k Na
Vi: k = f. (l/tm) . A m0 (gm/ g0) h. exp ( -Emo/k T)
Nh vy i vi quangph nguyn t, ng vi nhit nht nh caplasma, ta tm c cng caph, ta c th tm c mt cc nguyn t trongplasma (Na).
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Kho st nhit vt en:
Ngi ta to ra vt en bng cch dng mt bnh C c c mt lthng nh, bn trong bi en bng m hng, (c th coi l vten),bc x khi i qua l hng bn trong bnh, phn x nhiu ln lintip bn trong bnh, do hu ht nng lng bc x u b hp th.Din tch l hng va l b mt hp th, va l b mt bc x.
- Vt en l nhng vt hp th honton bc x chiu x chiu ti, ivi mi di sng v i vi migc ti.- Thc t khng c vt en tuyt i.
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ng ctrng ph pht xca vt en:
Bc x pht ra bi mt vt gm nhiu n sc,nng lng pht ra ng vi mi n sc khng
bng nhau v c c trng bi h s chinng lng n sc E.
ng cong biu din s bin thin ca Etheo bc sng c gi l ng c trng
ph pht x ca vt.
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Ta xc nh c c trng ph pht xca vt en bng th nghim:
A
C
ng cong biu din s bin thin ca ch trn in k G theo disng ca bc x ra bi vt en A chnh l ng cong biu din s bin thinca E theo hay chnh l ng c trngphpht x ca vt en.
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Bng cch thay i nhit cu vt en,ta v cnhiu c trng ng vi nhiu nhit khc nhau
Nhn xt:
+Nhn xt ng c trngtrn,ta thy E cc i ngvi mt di sng
m + Nng sutpht x ton
phn Rtng rt nhanh theonhit T ca vt en
+ Nhit ca vt en cng
cao th tr s ca m cngtin v pha di sngngn.
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Nhit bc x ca vtthc:
Rl nng sutpht x ton phn
Vi cc vt en, nng sutpht x ton phnR
vtun theo nh lutBolzamann:
Rv = T4
Vi cc vtthc (khng en) th nng sutpht x ton phn R < R
vVy: R < T4
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- t R= b*T 4 , vi b l en ca vt,ph thuc votnh cht v nhit ca vt ( b
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ng dng: Ho k quang hc:
Ho k dng o cc nhit cao: nhit ca mt vt nung , nhit ca l luynkim.
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Chm bc x pht ra t ngun A ( ng vai tr l vt en nhca s ca mtl luyn kim), hi t vo mt a nh K bngbc bi en. chi ca nh A trn a K bng chi cangun A. Nhit ca a K c o bng mt cp nhit inv mt in k G c nhy ln. Nhit ny t l vi
chi ca nh A, do t l vi chi ca vt en A. Bngmt bng o mu nhit c sn,ta suy ra nhit ca A
bng cch c s ch ca in k G Nu A khng phi vt en th nhit c ch l nhit bc
x T ca vt.
Nhit thc ca A l T vi T c tnh theo biu thc
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B phn tch nng lng
dng bn cong Lphng phpphn tch nnglng ion dng khiph k.
Cho bitthng tin v hmphn bnng lng v hmphn b khilng ca cc ion t khiplasma
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NGUYN TCCHUN ON
Trong plasma, mt s cc iondng c gia tc,vt ra khimin bao plasma v i vo mtkhu nh, n cp bn cong t
song song vi nhau
Cc ion ny chuyn ng trongin trng gia 2 bn cong
Ch c cc ion chuyn ng theong cong chnh gia 2 bn congi qua khe thot n detector
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XCNH NNG LNG ION in trng gia 2 bn cong tc dng lc ln cc ion lm chng chuyn ng
theo qu o cong,lc ny lc in trng ng vai tr lc hng tm:
in trng xuyn tm Ergia 2 bn cong c bn knh cong trung bnh Rxp x bng in trng gia 2 bn t song song cch nhau mt khong d, v
hiu in th gia 2 bn t 2VA
Nng lng Joule ca cc ion c khi lng M, vn tc vi
Th pt (1),(2) vo (3),ta c:
(eV) : Nng lng ion vi in th DC p vo 2 bncong
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T l vi: in th p vo cc bn cong
Dng hnh hc ca cc bn cong
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KHI PH K L dng c tch cc ht cht b ion ha theo khi
lng ca chng , hot dng da trn tc dng ca intrng hoc ttrng ln chm ion bay trong khnggian
Bungion ha
B phntch
Iondetector
Khiph
H thngx l d
liu
Bungchn
khng
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B PHN TCH
CC LOI B PHN TCH B phn tch t: c phn gii ln nhng cng knh B phn tch t cc: c phn gii ln,cu trc gn nh B phn tch theo thi gian bay: c cu trc gn nh nhng phn gii thp B phn tch cng hng ion cyclotron: khng c s dngph bin
L b phnphn ly cc ion c khi lng khc nhau thnh
tng phn da vo s lm chch hng ca cc ion so vi quo ban u ca chng khi i vo in,t trng ty theo t sm/z (mass/charge). im mu cht ca kthutl: phn gii tt,php o khilng chnh xc, nhy
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B PHN TCH TCC
Cu to: gm c 4trc,c t song song tng imt. Hai trc i nhau dccung cp in th +(U+V cost), hai trc i nhau cn li
c cung cp in th -(U+Vcos t)+(U+Vcost)
-(U+Vcost)
U:in th mt chiuV: in th xoay chiu
B PHN TCH T CC
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Hot ng:Tc dng ca in th gia cc tr lm thay i qu o cacc ion vo ng ng chnh gia ca 4tr. S iu chnh
dng AC va DC ch cho cc ion c cng t s m/z ndetectorti mtthi im, cn nhng ion khc c a vqu o ban u. Ph khi lng nhn c l do s iukhin qu o ca cc ion bng cch thay i in ptrncc tr. C 2 cch thay i in p: thay i , cn U,V l
khng i hoc thay i U,V sao cho U/V =const
B PHN TCH TCC
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mass scanning modeU/V = const
m1m3m4 m2
m3
m1
m4
m2
single mass transmission modeU,V= const,thay i
m2 m2 m2 m2m3
m1
m4
m2
T CC C KH NNG THAY I CH TRUYN
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PHP O TRC TIP HM PHN B NNG LNGKHNG DNG B PHN TCH
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PHP O HM PHN B NNG LNG DNG BPHN TCH TCC
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GIAO THOA K VIBA(MICROWAVE INTERFEROMETRY)
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GII THIU CHUNG
Tc dng
o mt electron ca dng plasma pht sng.
u im:Khng lm xo trn, v gy ra nhng hiu ng khng ng k trn plasma
Nguyn tc:
Nguyn tc hot ng da vo s thay i pha ca chm sng viba khi ni qua ct plasma. S thay i pha t l vi tch phn mt dc theong dn chm tia.
S thay i pha c xc nh da vo giao thoa k
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PHNG PHP
Bc x c lm chm li khi qua mi trng plasma (c ch skhc x ln hn 1 ).So snh pha ca bc x c lm chm nyvi pha ca bc x khi khng qua plasma..Xc nh lch phaca hai bc x ny , t xc nh c mt ca electron ctrong plasma.
Microwave
PLASMA
mixer DDC
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C S L THUYT
Quan h gia pha o c (rad) v phn thc ca ch s khc x ccho bi:
0
21
L
x dxT
QP
( !
Ch s khc x chunca giao thoa k
Ch s khc x cang plasma
L: qung ng truyn ca sng viba trong plasma (m)
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Khi tn s va chm nh hn tn s ca sng viba, ta c phn thc cach s khc x trong plasma khng nhim t l:
Trong : : mt electron (electron/m3)
: mt gii hn (mt ct) (electron/m3)
( )e
n x
cn
C S L THUYT
2
2
0
22
0
( ).
.1 1 1
.
.
e
p ee
cw c
e
n x e
n xmx
n e n
m
[ I[
I
! ! !
2
2
0
.
.e
p
e
n e
m[ I!
2
2
0
.
.c
e
n e[ I!
2
02
e wc
mn
eI[! electrons/m3.
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Trong hu ht plasma phng in pht sng: ne (x)
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Mt trung bnh ca electron trong plasma c nh ngha
0
1L
e en n x dx
L! (1. 6)
Thay 1.6 vo 1.5 ta c:
e
c
Ln
cn
TRJ! (1. 7)
0
2
4c
e
cn c mn
L Le
T I RJ J
T R! ( ! ( (1. 8)
C S L THUYT
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XC NH LCH PHA
Dng giao thoa k Michelson xc nh lch pha
- khcphc vic tn hiu quaplasma hailn ngi ta dng giaothoa k Mach-Zehnder
( qua mi trngplasma 1 ln)
microwave
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Dng giao thoa k Mach Zehnder
plasma
Tn hiu ch qua plasma 1 ln
microwave
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Giao thoa k Mach-Zehnder
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0
2
4c
e
cn c m
nL Le
T I RJ JT R! ( ! (
m : khi lng electron: tn s ca bc x viba
L : qung ng truyn ca sng viba trong plasma.
: hng s in mi
: tn s ca sng viba
e : ln in tch electron
R
0I
w[
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Cng dng : quan st hnh nh plasma
-Thi gian xy ra s phng in xung trong cht kh ch bng mt phntriu ca giy. V vy cn thit phi c s chp nh v quay phim cc nhanh ghili hnh nh ca plasma.
- Hin nay ngnh vt l thc nghim c trang b nhng bung chiuphim v my quay phim cc nhanh c th ghi c 10 000 000 bc nh trong mtgiy.
- Phng php chp nh nhanh v quay phim cc nhanh mang li
nhng kt qu tt p trong nghin cu nhng qu trnh tin trin nhanh. V dnh s phng in xung, tia la in v chp.
PHNG PHP QUAY PHIM TC CAO
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HNH NH QUAN ST PLASMA
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HNH NH QUAN ST PLASMA
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HNH NH QUAN ST PLASMA
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HNH NH QUAN ST PLASMA
HNH NH QUAN ST PLASMA
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HNH NH QUAN ST PLASMA
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Mt s phng php chn on khc
S dng u d t
Dng sng v tuyn
Tn x Thomson
Tn x Rayleigh, tn x RamanPhng php LIF-Laser Induced Fluorescence
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Cu to: u d t trng l
mt vng dy rt nhng knh ch vo
khong 1mm Vng dy c gi
vng u ng phng
in nh bng thchanh.
u d t
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Nguyn tc hot ng:u d c a vo trong
plasmaS bin thin t trng trongvng dy lm in p hai u cau d thay iMt my dao ng k ghi li s
thay i in p.Da vo s thay i in p tabit c s phn b t trngtrong plasma
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Vai tr
Cho bit c s phn b cng t trng trong ngphng inKhi bit s phn b t trng, ta c th thit lp s phn bdng in trong plasma.
Nhc imu d b bc hi, lm xut hin nhng tp cht trong plasma.
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Chn on Plasma tngin ly bng sng v tuyn
Tng in ly (ionosphere)
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Tng in ly l tng trn cng ca kh quyn do tcdng ca Mt Tri b ion ha
Plasma tng in ly c 3 loi ht: trung ha, ion velectron.
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Tn s plasma
ne: nng electronM: khi lng electron
e: in tch electron
S lan truyn sng in t trong plasmaNu tn s sng in t ffp sng truyn qua plasmaSng v tuyn c tn s thp nn b phn x bi tngin ly do chn on plasma ca tng in lyngi ta thng dng sng v tuyn
S phn x c dng chiu cao
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S phn x c dng chiu caov nng ca tng in ly
Tng in ly gm nhiu lp, khi tn s sng ln hn th n bphn x lp cao hn v ngc li
Pht tn hiu sng v tuyn c tng s xc nh ln tng inly v thu lai tn hiu phn x ta c th xc nh c nng plasma
Lower frequency Higher frequency
Gii thiu mt s php chn on
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Gii thiu mt s php chn onMt my pht sng v tuyn s pht sng ln tng in lyMt my thu s thu nhn tn hiu phn xTn hiu thu c s c x l di dng phDi y l mt v d minh ha
th gm 2 trc, trc tn s v trc nng lng
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Nng
Nng ca vngplasma t l vi tngnng lng phn xtr v
th trn gy ra bivng c nng plasma cao,
th di tng ngvi vng c nng thp
Nhi i
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Nhit ion
Vn tc ca ion t l vi rngca tn hiu,
iu ny gy ra bi hiu ngm rng vch ph Doppler
Nhit Ion c th c tnht vn tc v khi lng can theo cng thc
Cool Ions
Hot Ions
m v2 = 3 k T
m khi lng ionv vn tc ion
k hng s Boltzmann (1.38 * 10-23 J/K)
T nhit ion (K
)
Nhit El t
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Nhit Electron
Nhit electrons thng cao hn nhit ion
Lin h gia nhit ca chng tng ng vi linh gia nh ph v ch lm trn th
Cool electrons Hot electrons
T Th
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Tn x Thomson l tn x ca photon nhsng vi cc electron t do trong plasma
Da vo s photon b tn x ta bit c
nng electron c trong plasma. Bphn thu (detector) s ghi nhn s photonb tn x v x l cho hnh nh ph.
m rng ca ph theo hiu ngdopper cho bit vn tc ca electron t suy ra nhit ca electron
Tn x Thomson
S chn on
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S chn on
B tr th nghim tn x Thomson ti phng
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B tr th nghim tn x Thomson ti phngth nghim Polydiagnostic (H lan)
T R l i h R
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Tn x Rayleigh ltn x ca photon nh sng vi cc htnng (ion, nguyn t) trong plasma
Tn x raman: phn t cng lm tn x photon nh nguyn t,tuy nhin i vi phn tphi xt n nng lng quay haydao ng, v vy ph tn x c nhiu nh
Cch tin hnh chn on tng t nh tn x Thomson,trnc sph thu c ta xc nh c nhit v nng ccht nng
Tn x Rayleigh v Raman
Ph tn x Raman v Rayleigh
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Ph tn x Raman v Rayleigh
Phng php LIF Laser Induced Fluorescence
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fiber bundle
power meter
collection optics
Plasma
beam dump
Detector
Diode or Dye Laser
Phng php LIF - Laser Induced Fluorescence
Sdngngun sng laser kch thch cc nguyn t cc mcnng lng, mt s nguyn tnhnnng lng chuyn ln ccmc kch thch cao hn v sau bc x nh sng hunh quang vimt s bc sngnht nhBc x hunh quang thu c nhmt detector v x l bng mytnh, da trn ph thu c ta xc nh c nng htNgun laser thng dng l laser mu (330-900 nm) hoc laser Nd-
YAG laser (~380-900 nm)
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