Nanuf03, Bucharest, 7.-12. 9. 2003Stefan Kopecky Traps for fission product ions at IGISOL...

Nanuf03, Bucharest, 7.-12. 9. 2003Stefan Kopecky

Traps for fission product ions at IGISOL

Traps for fission product ions at IGISOL

•Experimental Facilities

•Mass Measurements

•Status and Future Perspectives

•Experimental Facilities

•Mass Measurements

•Status and Future Perspectives


IGISOL Fission Yields


IGISOL (Ion Guide Isotope Separation Online)

•Short delay Times

•Chemical Insensitive

•Large Energy Spread (100 eV)

•Continuous Beam


RFQ-Trap Layout


RFQ-cooler


Radial confinement

+Vcost

-Vcost


Axial confinement

Transmission 50 %Bunch width 2-3 sEnergy spread <1 eV


Collinear Laser-Spectroscopy

0

50

100

150

200

250

-500 -250 0 2500

5

10

15

b) With cooler (2001)

Ion flux 2 000 s-1

45 mins of data

a) Without cooler (1997)

Ion flux 12 000 s-1

5.25 hrs of data

Co

un

ts

Frequency relative to 90Zr centroid [MHz]

ion

res

I

Rincreased by a factor of 10

bgrR reduced by a factor of 20

<Rbgr>=Rph Tgate/Tacc

<Rres> = <Iion> Foverlap Fdoppler

geom PM Fatom


Magnet

•7T superconducting Magnet

•Magnex Scientific Ltd

•160mm warm bore

•2 homogenous regions 1cm3 10-6 and 10-7


Purification Trap Electrode Structure

-120

-100

-80

-60

-40

-20

0

Po

ten

tial [

V]


Radial Motion

-12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12

-12

-10

-8

-6

-4

-2

0

2

4

6

8

10

12

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15

without buffer gas with buffer gas

Magnetron motion -

Cyclotron motion +

-++=C= qB/m

Cyclotron radius decreasesMagnetron radius increases


Dipol –Excitation with -

1620 1640 1660 1680 1700 1720 1740 1760 1780 1800 1820 1840

100

200

300

400

500

600

Co

un

ts

Frequency for f-

-14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14

-14

-12

-10

-8

-6

-4

-2

0

2

4

6

8

10

12

14

HP33120A


Quadrupol –Excitation with C

853470 853480 853490 853500 853510 853520-50

0

50

100

150

200

250

300

350

400

Co

unts

/bin

Frequency [Hz]

126Xe

-14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14

-14

-12

-10

-8

-6

-4

-2

0

2

4

6

8

10

12

14

HP33120A


Fast-scheme

• Total cycle time 120ms

• p = 9.9 e-2 mbar

• Cooling time 55 ms

• - 5ms / 300mV

• C 55ms / 350mV

• FWHM = 35Hz

• R = m/m = 24500853440 853460 853480 853500 853520 853540 853560-50

0

50

100

150

200

250

300

350

Cou

nts/

bin

Frequency [Hz]

126Xe


Best Mass resolution

1854500 1854510 1854520 1854530 1854540 1854550 1854560-20

0

20

40

60

80

100

120

140

160

Cou

nts/

bin

Frequency [Hz]

1854780 1854800 1854820 1854840 1854860

0

200

400

600

800

1000

1200

Cou

nts/

bin

Frequency [Hz]

58Cu 58Ni

•FWHM=13,6Hz•R=135700•Mass Excess

Our result: -51674 +/- 30keVAME95: -51660 +/- 2.5keV

•FWHM=13,8Hz•R=134100


Purification Trap

• Transmission between 30-35 %

– spark ion source, stable Xe, Faraday-cup

– -activity, Fission products A=112 ( Rh-112), Si-detector

• Capturing efficiency of trap 60%

• Total Efficiency 20%

Front end for Precision Trap

Isobaric pure beams for Decay Spectroscopy

Mass Measurements


p-induced fission, A=112

960100 960150 960200 960250 960300 960350

0

700

1400

2100

2800

112Cd+96ZrO

112Ag +112Pd

112Rh

112Ru

Co

un

ts/b

in

Frequency [Hz]

Ru-112T1/2=1.75s

Rh-112T1/2=2.1s

Q=3.670MeV

Pd-112T1/2=21.03h

Q=6.8 MeV


Beam Purification

300 320 340 360 380 400

1

10

100

1000

112Rh112Rh

112Rh

112Ru

cou

nts

/bin

energy [keV]

no excitation omega_c = 960190 omega_c = 960150


Tof-methode

-14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10

-12

-10

-8

-6

-4

-2

0

2

4

6

8

10

12

50 100 150 2000

5

10

15

20

25

off-resonance on-resonance

coun

ts/c

hann

el

Time-of-flight [s]


Tof-resonance

2688790 2688800 2688810 2688820

104

106

108

110

112

114

116

118

40ArT

ime

of

Flig

ht [s

]

Frequency [Hz]


• Fundamental interactions and symmetries (< 1 keV)– Q-values of nuclear decay

• CVC theory and unitarity of CKM matrix

• Search for scalar and tensor currents

• Charge symmetry in nuclei (1 keV)– Isospin multiplets and Coulomb energy differences

• Nuclear structure (10-100 keV)– Global correlations (100 keV)

– Local correlations (10 keV)• Local deformation, coexistence, mixing and pairing

– Drip-line phenomena and halos (10 keV)

• Nuclear astrophysics (>10 keV)

What level of accuracies are needed?


Structure of neutron-rich Zr-isotopes

”Ground state changes from spherical to deformed via coexistence”

See, G. Lhersonneau et al.,Phys. Rev. C49(1994)1379 & refs.

No reliable direct mass measurements existed so far!

85 90 95 100

18.5

19.0

19.5

20.0

20.5

21.0

2=0.5

2=0.4

2=0.3

2=0.1

2=0.2

2=0.0

<r2 >

(fm

2 )

Mass number


896030 896040 896050 896060 896070 896080 896090

0

50

100

150

200

250

300

Co

un

ts/b

in

Frequency [Hz]

104Zr • Total cycle time 450ms

• p = 3 e-2 mbar

• Cooling time 330 ms

• - 15ms / 160mV

• C 90ms / 190mV

• FWHM = 18 Hz

• R = 45000

Zr-measurement


preliminary Zr results

95 96 97 98 99 100 101 102 103 104 105-600

-400

-200

0

200

400

600

800

Zr isotopic chain

M(exp.)M(AME)

M -

M(l

AM

E)

[ke

V]

A


preliminary Zr results

Zr96 Zr97 Zr98 Zr99 Zr100 Zr101 Zr102 Zr103 Zr10410000

10500

11000

11500

12000

12500

13000

13500S

2n [k

eV

] AME95 preliminary results


Nuclear Mean Field Calculation

95 96 97 98 99 100 101 102 103 104 105 106 107

9000

10000

11000

12000

13000

14000

15000

Exp HFB + THO + SLy4

S(2

N)

in k

eV

A

Stoitsov M.V, Dobaczewski J. and Nazarewicz W., to be published


Z=40, A=100 -region

8000

9000

10000

11000

12000

13000

14000

15000

16000

52 54 56 58 60 62 64 66 68

Mo

Nb

Zr

Y

Sr


Summary

•RFQ-Cooler•Reduce in energy spread of ion beam (<1eV)•Bunching of beam ( 2 - 3 s)Improved condition for Collinear Laser SpectroscopyFront end for Purification Trap

•Purification Trap•Isobaric Pure beams ( R = 20000-150000)•Cycle Times ( 120ms - 450ms)

Front End for Precision TrapDecay Spectroscopy of Exotic NucleiMass Measurement for Nuclear Structure Effects

•Precision TrapHigh Precision Mass Measurements

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Nanuf03, Bucharest, 7.-12. 9. 2003Stefan Kopecky Traps for fission product ions at IGISOL...

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