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In–source Laser Photoionization Spectroscopy of 191-218 Po isotopes at ISOLDE. Maxim Seliverstov. In–source Laser Photoionization Spectroscopy of 191-218 Po isotopes at ISOLDE. IS 456: Study of polonium isotopes ground state properties by simultaneous atomic- and nuclear-spectroscopy. - PowerPoint PPT Presentation
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Maxim Seliverstov
In–source Laser Photoionization Spectroscopy of 191-218Po isotopes at
ISOLDE
ISOLDE Workshop and Users meeting 200918-20 November 2009 CERN
In–source Laser Photoionization Spectroscopy of 191-218Po isotopes at ISOLDE
IS 456: Study of polonium isotopes ground state properties by simultaneous atomic- and nuclear-spectroscopy
Collaboration: CERN/ISOLDE - IKS Leuven-Mainz University- PNPI Gatchina- IPN Orsay
A.N. Andreyev, S. Antalic, A.E. Barzakh, B. Bastin, J. Billowes, J. Büscher, T.E. Cocolios, I. Darby,W. Dexters, D.V. Fedorov, V.N. Fedosseev, K. Flanagan, S. Franchoo, S. Fritzsche, G. Huber, M. Huyse, M. Keupers, U. Köster, Yu. Kudryavtsev, B.A. Marsh, P. Molkanov, M.D. Seliverstov, M. Sjödin, J. Van de Walle, P. Van Duppen, M. Venhart, S. Zemlyanoy, Yu. Volkov3
ISOLDE Workshop and Users meeting 200918-20 November 2009 CERN
In–source Laser Photoionization Spectroscopy of 191-218Po isotopes at ISOLDE
ContentsMotivationIn-source resonant photoionization spectroscopy at ISOLDEIsotope shifts and charge radii for even-A neutron-deficient Po isotopes:
A = 192-198 A = 200-210 A = 200-218
Hyperfine structure of the odd-A Po isotopes and isomers Conclusions and outlook
ISOLDE Workshop and Users meeting 200918-20 November 2009 CERN
Motivation
ISOLDE Workshop and Users meeting 200918-20 November 2009 CERN
nuclear ground and isomeric state properties : δ r 2
100 105 110 115 120 125 130
Pt (Z = 78)
Bi (Z = 83)
Po (Z = 84)
Hg (Z = 80)
N =
104
N =
126
r 2 ,
fm2
N
, Ground states , Isomers
Pb (Z = 82)= 0.1 fm2
Level systematics for the neutron-deficient polonium isotopes.R. Julin et al., J. Phys. G: Nucl. Part. Phys 27 R109 (2001).
????
????
6p4 3P2
6p37s 5S2
6p37p 5P2
Continuum
Po ground state
λ1 =255.8 nm
λ2 = 843.38 nm
λ3 = 510.6 nm (CVL) or 535 nm (Nd:YAG)
hfs0
hfs1
hfs2
8.4168 eV
In–source Laser Photoionization Spectroscopy at ISOLDE
Laser Ion Source (LIS)target
ionizer
Laser beams
Mass separator
Isotope shift, dr 2
I , Q S
Detection:Faraday Cupα-detection (Windmill)β-detection (tape-station)γ-detection (tape-station)
*
*This tranistion was already used for optical spectroscopy (Kowalewska et al, Phys. Rev. A, 44 R1442, 1991.)
Photoionization scheme for PoT.E. Cocolios et al. NIM B 266 (2008)
4403
Isotope shifts of the even-A Po isotopes
11853.2 11853.4 11853.6 11853.8 11854.00
50
100
Wavenumber, cm-1
192Po
0.0
0.5
1.0
194Po
0
50000
196Po
0
2000
4000
198Po
020004000
200Po
0
10000
20000
202Po
0
1000
2000204Po
0.0
0.2
0.4206Po
0.0
0.4
0.8208Po
0.00.20.40.6
210Po
0
400
800216Po
0500
10001500
218Po
ion
curre
nt
Isotope shift A,A’:
dA,A’= F * lA,A’ + (NMS+SMS)Rms charge radius :
lA,A’ = r 2 + C2dr 4 + … ≈ 0.93 dr 2
A ΔνA,196 , MHz T1/2, s Detection
192 –1037(150) 32 ms α
194 –372(120) 392 ms α
196 0 5.56 s α
198 –162 (130) 1.77 m α
200 –905(40) 11.5 m γ
202 –2009(100) 44.7 m β
204 –3315(50) 3.53 h γ
206 –4692(60) 8.8 d FC
208 –6104(60) 2.9 a FC
210 –7735(45) 138 d FC
216 –16555(55) 145 ms α
218 –19259(75) 3.1 m αPreliminaryT1/2 =33
ms<1 ion/s
Isotope shifts for 200-210Po:λ=255 nm and λ=843 nm
0 20000 40000 60000 800000
-10000
-20000
-30000
-40000
A,A'843
A,A'255
F843/F255= 0.45(3) from King plot
King plot:
F255 =29140 MHz/fm2
F843 = -12976 MHz/fm2
F843/F255= 0.44
Limited knowledge on the atomic structure of polonium: the electronic F-factor for the transition of interest in unknown.
Previous work by Kowalewska et al. is locked on the FRDM at A=206-208 to extract the F-factor for the transition at 255.8 nm.
Large-scale electronic computations by S. Fritzsche using the GRASP code also give the F-factor from a theoretical approach for both transitions.
ΔσA,A’ = ΔνA,A’ AA’/(A-A’)
Charge radii for 192-218Po
Preliminary105 110 115 120 125 130 135
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
d r2
, fm
2
N
Our data (new) Our data
N = 126
The experimental error bars are smaller than the symbol size.
Charge radii of neutron-deficient Po isotopes
95 100 105 110 115 120 125 130
Pt (Z = 78)
Po (Z = 84)
Hg (Z = 80)
N =
104
N =
126
r 2 ,
fm2
N
Ground state Isomer Spherical Droplet
model prediction
Pb (Z = 82)
= 0.1 fm2
The experimental error bar is smaller than the symbol size. The distance between the different chains is chosen arbitrarily for better display. One minor division on the vertical scale corresponds to 0.1 fm2Preliminary
Charge radii of neutron-deficient Po isotopes: shell-closure effect at N = 126
115 120 125 130 135 140 145 150
Rn (Z = 86)
Po (Z = 84)
Ra (Z = 88)N =
126
r 2 ,
fm2
N
Pb (Z = 82)
= 0.1 fm2
Preliminary
Elementdr 2N,N-2(N>126)––––––––––––––––dr 2N,N-2(N<126)
Pb 1.9
Po 2.1
Rn 2.2
Ra 2.2
Hyperfine structure of the odd-A Po isotopes
Odd-A Po isotopes: preliminary analysis
0
5000
10000
15000
E
0
10000
20000
High spin spin (13/2)
Low spin (3/2)
11853.6 11853.8 11854.0 11854.2
0
20
40
195Po
193Po
11853.6 11853.8 11854.0 11854.20
1020
30
4050
60
Wavenumber, cm-1Wavenumber, cm-1
0
500
1000
1500
2000
2500
197Po
0
10000
20000
Odd-A Po isotopes: preliminary analysis
100 102 104 106 108 110 112 114 116 118 120 122 124-1.6
-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
3p3/2
n
.m.)
N
, Pb, I = 13/2, Pb, I = 3/2
Hg, I = 13/2 Po, I = 3/2 Po, I = 13/2
1i13/2
Lit. data
Estimations (preliminary) of magnetic moments (193-197Po):
Preliminary!…to be continued191Po, 199-203Po…
Conclusions and outlook
Extension of the laser spectroscopy studies to the neutron deficient and neutron reach isotopes (and isomers) of Po: from 191Po to 218Po:
Isotope shifts for the even-A 192-218Po are extractedData on charge radii of 192-218Po are obtained, but the analysis is ongoing…Large and early departure of the charge radii from the Sperical Droplet Model prediction was observed for neutron deficient Po isotopesNeutron shell closure effect (around N = 126) was observed Spectra of the odd-A 191-211Po are obtained. Extraction of the isotope shifts and hyperfine splitting constants is ongoing…Some interesting effects are expected: dramatic change of the magnetic moments for the light Po isotopes, inverse odd-even staggering…
Thank you for your attention
Comparison with the theory
This picture has all the data and calculation that we have available at the moment. It is very crowded but it is also complete.
the BMF calculations are on private communication from P.-H. Heenen