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Лазерно-спектроскопические исследования изотопов таллия. I. Аномалия сверхтонкой структуры и возможность изучения распределения ядерной намагниченности. - PowerPoint PPT Presentation
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Лазерно-спектроскопические исследования изотопов таллия.
I. Аномалия сверхтонкой структуры и возможность изучения распределения
ядерной намагниченности.
A. E. Барзах, Ю. M. Волков, В. С. Иванов, K. A. Мезилев, П. Л. Молканов, Ф. В. Мороз, С. Ю. Орлов, В. Н. Пантелеев, Д. В. Федоров
1. Общий обзор результатов по исследованию изотопов таллия.
2. Экспериментальная установка. 3. Что такое «аномалия сверхтонкой структуры» и новый
метод ее измерения.4. Экспериментальные результаты: HFA для изомеров
таллия с I=9/2. Какую информацию о ядреможно получить из данных по HFA?
ionization efficiency ~ 3-4%2 2
1/2 3/2
276.9 511 5786 6
nm nm nm
NBL CVLp P d D continuum
183Tl, I=1/2, T1/2=6.9 s
184Tl, I=7, T1/2=11 s
186Tl, I=7, T1/2=27.5 s
185Tl, I=1/2, T1/2=19.5 s
185Tl, I=9/2, T1/2=1.8 s
186Tl, I=10, T1/2=2.9 s
187Tl, I=1/2, T1/2=51 s
187Tl, I=9/2, T1/2=15.6 s
188Tl, I=7, T1/2=71 s
188Tl, I=9, T1/2=0.04 s
190Tl, I=7, T1/2=3.7 m
189Tl, I=1/2, T1/2=2.6 m
189Tl, I=9/2, T1/2=84 s
190Tl, I=2, T1/2=2.6 m
191Tl, I=1/2, T1/2=2.2 m
191Tl, I=9/2, T1/2=5.2 m
192Tl, I=7, T1/2=10.8 m
192Tl, I=2, T1/2=9.6 m
194Tl, I=7, T1/2=32.8 m
193Tl, I=1/2, T1/2=21.6 m
193Tl, I=9/2, T1/2=2.1 m
194Tl, I=2, T1/2=33 m
196Tl, I=7, T1/2=1.41 h
195Tl, I=1/2, T1/2=1.16 h
195Tl, I=9/2, T1/2=3.6 s
196Tl, I=2, T1/2=1.84 h
197Tl, I=1/2, T1/2=2.84 h
197Tl, I=9/2, T1/2=0.54 s
198Tl, I=7, T1/2=1.87 h
198Tl, I=2, T1/2=5.3 h
200Tl, I=2, T1/2=26.1 h
199Tl, I=1/2, T1/2=7.42 h
199Tl, I=9/2, T1/2=0.028 s
201Tl, I=1/2, T1/2=72.9 h
201Tl, I=9/2, T1/2=0.002 s
202Tl, I=2, T1/2=12.23 d
203Tl, I=1/2, stable
? ?
measured previously for 2
3/26 p P 21/27s S
transition (535.2 nm)unknown
g.s.
m.s., I=2
m.s., I=9/2}
Before our experiments:
183Tl, I=1/2, T1/2=6.9 s
184Tl, I=7, T1/2=11 s
185Tl, I=1/2, T1/2=19.5 s
185Tl, I=9/2, T1/2=1.8 s
186Tl, I=10, T1/2=2.9 s
188Tl, I=9, T1/2=0.04 s
195Tl, I=9/2, T1/2=3.6 s
197Tl, I=9/2, T1/2=0.54 s
189Tl, I=1/2, T1/2=2.6 m
187Tl, I=1/2, T1/2=51 s
191Tl, I=1/2, T1/2=2.2 m
193Tl, I=1/2, T1/2=21.6 m
196Tl, I=7, T1/2=1.41 h
195Tl, I=1/2, T1/2=1.16 h
196Tl, I=2, T1/2=1.84 h
197Tl, I=1/2, T1/2=2.84 h
198Tl, I=7, T1/2=1.87 h
198Tl, I=2, T1/2=5.3 h
200Tl, I=2, T1/2=26.1 h
199Tl, I=1/2, T1/2=7.42 h
199Tl, I=9/2, T1/2=0.028 s
201Tl, I=1/2, T1/2=72.9 h
201Tl, I=9/2, T1/2=0.002 s
202Tl, I=2, T1/2=12.23 d
? ?
…
186Tl, I=7, T1/2=27.5 s
187Tl, I=9/2, T1/2=15.6 s
188Tl, I=7, T1/2=71 s
190Tl, I=7, T1/2=3.7 m
189Tl, I=9/2, T1/2=84 s
190Tl, I=2, T1/2=2.6 m
191Tl, I=9/2, T1/2=5.2 m
192Tl, I=7, T1/2=10.8 m
192Tl, I=2, T1/2=9.6 m
194Tl, I=7, T1/2=32.8 m
193Tl, I=9/2, T1/2=2.1 m
194Tl, I=2, T1/2=33 m
203Tl, I=1/2, stable
207Tl, I=1/2, T1/2=4.77 m
repeated for another atomic transition
(276.9 nm)
for King-plot calibration
21/26 p P 2
3/26d D
measured for the first time
183Tl, I=1/2, T1/2=6.9 s
184Tl, I=7, T1/2=11 s
185Tl, I=1/2, T1/2=19.5 s
185Tl, I=9/2, T1/2=1.8 s
183Tl, I=1/2, T1/2=6.9 s
184Tl, I=7, T1/2=11 s
183Tl, I=9/2, T1/2= 0.053 s
184Tl, I>8, T1/2<1 s
180Tl, I=(4,5), T1/2=1.1 s
181Tl, I=1/2, T1/2=3.4 s
182Tl, I=(4,5), T1/2=3.1 s
179Tl, I=1/2, T1/2= 0.23 s
181Tl, I=9/2, T1/2= 0.0014 s
179Tl, I=9/2, T1/2= 0.0015 s
IRIS
IRIS & ISOLDE
ISOLDE
unknown
186Tl, I=10, T1/2= 2.9 s
Laser Ion Source (LIS)
target
ionizer
Laser beams
Mass separatorprotons
5000
10000
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0
400
800
1200
0400800
1200
0200400600
1000
2000
3000
-12000 -9000 -6000 -3000 0 3000 6000 9000 120000
50010001500
A=191m, I=9/2E= 265, 326 keV
T1/2= 313 s
A=193m, I=9/2E= 365 keV
T1/2=127 s
A=195m, I=9/2E=384 keV
T1/2=3.6 s
(MHz)
coun
tsco
unts
coun
tsco
unts
IS
A=197m, I=9/2E=386 keV
T1/2=0.54 s
coun
tsI FC
, arb
. uni
ts
A=205, I=1/2Faraday cupstable isotope
A=189m, I=9/2E= 216 keV
T1/2= 84 s
5000
10000
15000
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-12000 -9000 -6000 -3000 0 3000 6000 9000 120000
50010001500
A=191m, I=9/2E= 265, 326 keV
T1/2= 313 s
A=193m, I=9/2E= 365 keV
T1/2=127 s
A=195m, I=9/2E=384 keV
T1/2=3.6 s
(MHz)
coun
tsco
unts
coun
tsco
unts
IS
A=197m, I=9/2E=386 keV
T1/2=0.54 s
coun
tsI FC
, arb
. uni
ts
A=205, I=1/2Faraday cupstable isotope
A=189m, I=9/2E= 216 keV
T1/2= 84 s
2.4x107 2.8x107 3.2x107 3.6x107 4.0x1071.2x107
1.4x107
1.6x107
1.8x107
2.0x107
2.2x107
2.4x107
2.6x107
2.8x107
mg
m
A, A'
=A, A'AA'/(A-A')
King plot for 535 nm and 277 nm lines in Tl
A
,205
(277
nm
)
A,205 (535 nm)
187m
203
207
191m189m
193m
190
186
188
192
194
g
5000
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0400800
1200
0200400600
1000
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3000
-12000 -9000 -6000 -3000 0 3000 6000 9000 120000
50010001500
A=191m, I=9/2E= 265, 326 keV
T1/2= 313 s
A=193m, I=9/2E= 365 keV
T1/2=127 s
A=195m, I=9/2E=384 keV
T1/2=3.6 s
(MHz)
coun
tsco
unts
coun
tsco
unts
IS
A=197m, I=9/2E=386 keV
T1/2=0.54 s
coun
tsI FC
, arb
. uni
ts
A=205, I=1/2Faraday cupstable isotope
A=189m, I=9/2E= 216 keV
T1/2= 84 s
2 1
2
Ia
aI
205205 205
A
A A
A AA
constI a
I a
I a
1 2 1 1 2
1 2 2
1A A a I
a I
HFA:
A
A A
constI a
(1 )pointa a 1 2
1 2( )A A
A A
1 2 1 1 2
1 2 2
1A A a I
a I
205205
205 205
(1 )AA AA
I a
I a
2mr
2( ) 0.34Z 1 2
1 2
1/2
1/2
( )0.3
( )
A A
A A
p
s
Our case: we have studiedstate with p1/2 valence electron;previously state with s1/2 valence electron has been studied
Ratio of the electron density at the nucleus for p1/2 state and s1/2 state: for Z=81, so one can expect:
,22
11
2211 , Aln
AlnA
lnln a
a
)()(1 2211,
, 2121
2
2211
1
221122
2
11
1lnln AAAA
Alnln
Alnlnln
Aln
A
DHFA:
Ratio can have a different value for different isotopes
because the atomic states with different n, l
have different sensitivity to the nuclear magnetization distribution.
All 21 ,
42036
205 10)15(050.12/1
P
1/2
205 203 47 3.4(15) 10S
1/2 1/26 7 4205 203 2.4(1.5) 10P S
205205 205
( )
( )A A
nl
I a nl
I a nl
187 188 189 190 191 192 193
3.65
3.70
3.75
3.80
3.85
3.90
3.95
(
N )
A
1/26 p
1/27s
205(1 )AA nl nl
1/2 1/2
1/2 1/2
6 77 6 205( ) ( ) (1 )P S
S P AA A
large errors prevent to trace isotopic dependence of DHFA
A
187 0.5(2.6)×10-2
189 1.5(1.1)×10-2
191 1.67(93)×10-2
193 1.36(66)×10-2
2/12/1 76205
SA
P
1/2 1/26 7 2205 ( 9/2)mean : 1.45(48) 10P S
A I exp
Magnetic moments for Tl isomers with I=9/2
187 188 189 190 191 192 193
3.65
3.70
3.75
3.80
3.85
3.90
3.95
(
N )
A
1/26 p
1/27s1/2 1/2
1/2
6 76 205 ( 9/2)(1 )P S
P A I
1/2 1/26 7 2205 ( 9/2) 1.45(48) 10P S
A I exp
42 24 4
2 2 22 2
, 1 ss m m m m m
s
b d rb d r k r
b d r
I
I
4
32
Ls
LI
I
ss gg
gg
g
gC
27)2/9(
6205 102.1)(2/12/1
theorSIA
P 1/2 1/26 7 2205 ( 9/2) 1.45(48) 10P S
A I exp
42036
205 10)15(050.12/1
P
DHFA calculationAtomic part: atomic many-body technique
(relativistic “coupled-cluster” approach) by A.-M. Mårtensson-Pendrill
2
2 31 1 .
2 3 2 3n s s
nd C C
n n
1 2
1 2
21/2
1/2
( )( ) 0.31 ( . : ( ) 0.34)
( )
A A
A A
ptheor cf Z
s
Single shell-modelconfiguration:
(in our case: pure h9/2 intruder state)
Magnetic moments for Tl isomers with I=9/2
Aµ (μN)
(literature data)
µ (μN)
with the new HFA
correction
185 3.849(90)
187 3.7932(65) 3.712(27)
189 3.8776(63) 3.760(28)
191 3.9034(48) 3.785(28)
193 3.9482(39) 3.829(28)
195 3.898(38)
197 4.047(69)
205205
205 205
( )(1 )
( )AA A
A nl
I a nl
I a nl
184 186 188 190 192 194
0.2
0.3
0.4
0.5
0.6
0.7
IRIS
literature
(
N )
A
Magnetic moments for Tl isotopes with I=7 (without HFA)
1/26 p
1/27s
22 2( ) ( ) ( )s m mA b k r A d A
atomic part: independent of A
nuclear configuration part: independent of A(as magnetic moment constancy shows)
1/26 p
1/27s
181 183 185 187 189 191 193 195 197 199 201 203 205 207
1.5
1.6
1.7
1.8
1.9
, n
.m.
IRIS
literature
A
Magnetic moments for Tl isotopes with I=1/2 (without HFA)
22 2( ) ( ) ( )s m mA b k r A d A
1. Продемонстрирована работоспособность и эффективностьновой лазерной установки на масс-сепараторе ИРИС.
2. Впервые измерена аномалия сверхтонкой структуры для изомеров таллия с I=9/2, что позволило, в частности, уточнитьзначения ранее измеренных магнитных моментов.
3. Показано, что современные атомные расчеты удовлетворительноописывают «электронные» факторы, необходимые для вычисленияHFA.
4. Измерение DHFA в сочетании с современными атомными расчетами открывает возможность исследования распределениянамагниченности для короткоживущих удаленных ядер.
179 183 187 191 195 199 203 207-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
2 >
1/2 =0.25
2 >
1/2 =0.2
2 >1/2 =0.15
2 >
1/2 =0.1
<r2 >
A, 2
05
fm2
A
I=1/2 I=9/2 I=2 I=7 I=5 Gatchina
(preliminary) ISOLDE
(preliminary)
2 >
1/2 =0
<2>1/2 (205Tl)=0.069 (Raman)