positron anniihilation lifetime spectroscopy fundamentals and applications
DESCRIPTION
POSITRON ANNIIHILATION LIFETIME SPECTROSCOPY Fundamentals and applications. Bożena Jasińska Institute of Physics Maria Curie Sklodowska University. II SYMPOSIUM ON APPLIED NUCLEAR PHYSICS AND INNOVATIVE TECHNOLOGIES Jagiellonian University , Kraków, September 24 - 27, 2014. 511 keV. - PowerPoint PPT PresentationTRANSCRIPT
POSITRON ANNIIHILATION LIFETIME SPECTROSCOPYFundamentals and applications
Bożena JasińskaInstitute of Physics
Maria Curie Sklodowska University
II SYMPOSIUM ON APPLIED NUCLEAR PHYSICS AND INNOVATIVE TECHNOLOGIES
Jagiellonian University, Kraków, September 24 - 27, 2014
+_
511 keV
511 keV
Annihilation
outline
1. POSITRON AND POSITRONIUM2. ETE MODEL 3. EXPERIMENTAL SETUP
4. METALS AND OXIDES5. PHASE TRANSITION IN POLYMERS6. POROUS MATERIALS
+_
511 keV
511 keV
Annihilation
POSITRONIUM in the vacuum
= 125 psp-Ps = (7,98950 ± 0,00002) ns-1
= 142 nso-Ps = (7,03993 ± 0,00001) ms-1
PARAPOSITRONIUM
ORTOPOSITRONIUM
POSITRONINUMPOSITRONINUMIN THE IN THE
MATTERMATTER
POSITRONIUM in the condensed matter
thermallization
Processes leading to o-Ps lifetime shortening:- ortho-para conversion- quenching- pick-off
POSITRONIUM in the condensed matter
pick-off process
Shortening of the o-Ps lifetime value: 1 to 142 ns
0R R = R + RR 0 0L .O . R o e lig " P o s itro n A n n ih ila tio n " (1 9 6 7 ) 1 2 7A .P . B u c h ik h in e t a l. Z E T F 6 0 (1 9 7 1 ) 1 1 3 6
S .J . T a o , J .C h e m .P h y s . 5 6 (1 9 7 2 ) 5 4 9 9M . E ld ru p e t a l. C h e m .P h y s . 6 3 (1 9 8 1 ) 5 1
R
R
22drr)r(4P
R
R2sin
2
1
R
R1bpo
1λpo=λbP
0.0 0.2 0.4 0.6 0.8 1.0
V, nm
0
2
4
6
8
Life
time,
ns
sphe ll
cube
cuboid
3
Dependence of the mean o-Ps lifetime value on the free volume sizeand shape
POSITRONIUM in the condensed matter
Porous materials
1 s
1 p
1 d2 s
1 f
2 p1 g
2 d
20
2nl
Ps
2
nlR
X
m2E
EXCITED STATESSpherical potential well
Porous materials
Decay constant for nl-th state, spherical shape:
Decay constanst of pick-off process (averaged over all populated states) :
T. Goworek, K. Ciesielski, B. Jasińska and J. Wawryszczuk, Chem. Phys. 230, 305, (1998).
K. Ciesielski, A.L. Dawidowicz, T. Goworek, B. Jasińska and J. Wawryszczuk, Chem. Phys. Lett., 289, 41, (1998).
ETE model
.k T
)R(Ee x pg
k T)R(E
e x pg)R(N
1i
ii
N
1i
iiipo
drr)r(jdrr)r(j 22l
X
0
X
R/RX
22lb
nlpo
nlnl
0nl
drr)r(jdrr)r(j 22l
X
0
X
R/RX
22lb
nlpo
nlnl
0nl
Decay constant of nm-th state, cyllindrical shape:
Porous materials
PALS vs LN
Porous materials
2.6y
3.7ps
+ 90.4%, EC 9.5%
+ 0.006%
Na2211
*2210 Ne
Ne2210
1.274
0
PALSPositron Annihilation Lifetime Spectroscopy
1274 keV 511 keV
t
511 keV
1274 keV
co
un
ts
Channel number (energy)
PAL spectrometer
PAL spectrometer
Lifetime spectrum
TdttZttRNtN
''
0
'0
Spectrum analysis – convolution („LT”)
J. Kansy, Nucl. Instr. Methods A 374, 235 (1996).
ii
ii
texp
ItZ
Time, ns
cou
nts
examples
Fitted components:
2. Intensity of i-th component
(I)
1. Mean lifetime value
()
Defected metal
time time
cou
nts
Nondefected metal
-200 -100 0 100 200
T [oC ]
2.5
3.5
4.5
5.5
3 [n
s]
100 200 300 400 500
T [K ]
0.1
0.2
0.3
0.4
0.5
0.6
Vh [n
m3 ]
CYTOP
Glass transitionT=1080 C
M. Śniegocka, PhD Thesis, Lublin 2010
POLYMERS
240 250 260 270 280 290 300 310 320TEM PER A TU R A, K
1.2
1.6
2
2.4
2.8
3.2
ns
Phase transition in alkanes
C13H2
8C15H3
2C17H3
6C19H4
0
B. Zgardzińska, PhD Thesis, Lublin 2008
Low-kmaterials
pollution sorption
photonics
Porous materials
100 200 300 400 500TEM PER ATU R E, K
0
20
40
60
80
100
LIF
ET
IME
, ns
100 200 300 400 500TEM PER ATU R E, K
0
10
20
30
40
INT
EN
SIT
Y, %
R = 0.99 nmR = 1.55 nm
R = 2.38 nm
http://chem.ch.huji.ac.il/~renata/
PHOTON ACTIVE GLASSES
Porous materials
0 20 40 60 80 100 120 140
, ns
0
0.004
0.008
0.012dI
/d
MCM-41
1 102 4 6 8 20 40 600.80.6
D, nm
0
0.02
0.04
0.06
0.08
dV/d
D
Porous materials
[1] R. Zaleski, PhD thesis, Lublin (2005)
110 115 120 125 130 135
LIFETIME [ns]
10-5
10-4
10-3
10-2
10-1
INT
EN
SIT
Y
1 - PG, 2 – PG + dye3 – PG + AgNPs
Porous materials
Thank you for your attention Thank you for your attention