Общий обзор результатов по исследованию изотопов...

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

15000

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

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

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

10000

15000

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

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)