“Reaction studies about the Q“Reaction studies about the Q- … · 2009. 10. 15. · Technische...

Technische Universität München

“Reaction studies about the Q“Reaction studies about the Q--value influencevalue influenceon the production of superheavy elements”on the production of superheavy elements”

Reimar GraegerReimar GraegerSeventhSeventh Workshop onWorkshop on thethe chemistrychemistry ofof thethe heaviestheaviest elementselements

Mainz, GermanyMainz, GermanyOctoberOctober 1111thth -- 1313thth, 2009, 2009


HsHs -- ElementElement 108108

•• TransactinideTransactinide ––group VIII elementgroup VIII element

•• 270270Hs is double magic nucleusHs is double magic nucleuswith closed deformed shellwith closed deformed shellatat Z=Z=108,108, N=N=162162

•• Forms volatileForms volatile tetroxidetetroxide ––HsOHsO44 –– very high yield ofvery high yield ofchemical separation!chemical separation!

•• First synthesized at GSIFirst synthesized at GSI(Darmstadt) in year 1984(Darmstadt) in year 1984208208PbPb((5858FeFe, 1n, 1n))265265HsHs

116

114

110108

104106

112

114

112

HsDs

Sg

Rf

No

150 155 160 165 170 175 180

8

9

10

11

12

Neutron number

118Z-even

even-eveneven-odd

Q

New data


CutoutCutout fromfrom thethe chartchart ofof nuclidesnuclides208Pb(70Zn,1n) 277112

248Cm(26Mg,3-5n) 269-271Hs238U(36S,3-5n) 269-271Hs226Ra(48Ca,3-5n) 269-271Hs


Confirmation of synthesis ofConfirmation of synthesis of 277277112112S. Hofmann et al., Z. Phys. A354, 229 (1996)S. Hofmann et al., Z. Phys. A354, 229 (1996)

277112

280 s1

273110

110 s2

269Hs

19.7 s3

265Sg

7.4 s4

261Rf

4.7 s5

257No

15.0 s6

11.08

11.45

9.23

(4.60)

8.52

8.34

Hs

1

265Sg

17.1 s2

261Rf

0.85 s3

269Hs

19.188.88

8.90

265Sg

4.4 s2 8.69

8.50

261Rf

2.4 s3

8.50

257No

55.6 s4 8.21

269

ChCh. E. Düllmann et al., Nature. E. Düllmann et al., Nature 418, 859 (2002)418, 859 (2002)

SHIPSHIP @ GSI@ GSISHIPSHIP @ GSI@ GSIFeb 1996Feb 1996Feb 1996Feb 1996

SHIPSHIP @ GSI@ GSIFeb 1996Feb 1996

HassiumHassium::ChemistryChemistrypossiblepossible!!



HsHs--chemistrychemistryMay 2001May 2001


Doubly Magic NucleusDoubly Magic Nucleus 270270HsHsJ. Dvorak et al., Phys. Rev.J. Dvorak et al., Phys. Rev. LettLett.. 9797, 242501 (2006), 242501 (2006)

9.18 - 9.22

269Hs8.91 - 9.039.06 - 9.139.18 - 9.22 8.67 - 8.92

270Hs

8.67 - 8.92 9.23 - 9.30

271Hs

9.02 - 9.169.23 - 9.30

266Sg50ms - 1.6s

SF

263Rf12 s

SF

8.24; 8.29

257No

2.5; 21 s

8.24; 8.29

267Sg0.5 – 4.5 m

8.20; SF

269Hs 270Hs 271Hs11 + 2 7 5 + 1

269Hs 270Hs 271Hs11 + 2 7 5 + 1

2626MgMg ++ 248248CmCm 274Hs*274Hs*

5 new isotopes discovered!5 new isotopes discovered!

261Rf78 s 2.7 s

8.518.29 SF

265Sg7 s 15 s

8.94;8.84;8.76 8.69

July 2008 at FLNR:July 2008 at FLNR:Decay properties forDecay properties for 270270HsHsconfirmed!confirmed!


269,270,271Hs269,270,271Hs2626MgMg ++ 248248CmCm 274Hs*274Hs*

269,270,271Hs269,270,271Hs4848Ca +Ca + 226226RaRa 274Hs*274Hs*

Q =Q = -- 82,2 MeV82,2 MeV

B = 126,9 MeVB = 126,9 MeV

Q =Q = -- 116,7 MeV116,7 MeV

B = 159,1 MeVB = 159,1 MeV

269,270,271Hs269,270,271Hs++ 238238UU 274Hs*274Hs*

Q =Q = -- 153,9 MeV153,9 MeV

B = 187,0 MeVB = 187,0 MeV

BB -- Q = 44,7 MeVQ = 44,7 MeV

BB -- Q = 42,4 MeVQ = 42,4 MeV

BB -- Q = 33,1 MeVQ = 33,1 MeV


4n4n--channel Excitation functions (channel Excitation functions (270270Hs)Hs)

BBBassBass

E* (CN 274Hs*)

(4n 270Hs)EVREVR == captcapt*P*PCNCN**WWsursurEVREVR == captcapt*P*PCNCN**WWsursur

CNCNCNCNCNCN ~ P~ PCNCN ~ asymmetry~ asymmetry

Above the barrier:Above the barrier:EVREVR ~~

Below the barrier:Below the barrier:EVREVR ~~ ((BBBassBass –– Q) ~ QQ) ~ Q--valuevalue

From Ch. E. Düllmann

Z.H. Liu and J.-D. Bao, Physical Review C 74, 057602 (2006)


Hassium separator experiment at DGFRSHassium separator experiment at DGFRS226226Ra(Ra(4848Ca,Ca, xxnn))274274--xxHsHs

FLNR and TUM collaborationFLNR and TUM collaborationDGFRS @ FLNR, DubnaDGFRS @ FLNR, DubnaJune 2008June 2008 -- August 2008August 2008

November 2008November 2008 -- FebruaryFebruary 20092009

U400U400 cyclotroncyclotron


Experimental setup:Experimental setup:The Dubna GasThe Dubna Gas--Filled Recoil SeparatorFilled Recoil Separator

Beam (Beam (4848Ca)Ca)

Target (Target (226226Ra)Ra)

DipoleDipole

QuadrupolesQuadrupoles

FocalplainFocalplain

C.E. Düllmann et al 2005C.E. Düllmann et al 2005

226Ra

269-271Hs48Ca


Target: 234 g/cm2 226RaO (1st experiment)Targetwheelarea: 36 cm2 362 g/cm2 226RaO (2nd experiment)Backing: 1.5 m Ti

Detector: detection efficiency: = 87%SF ~ 100%

energy resolution: 50-110 keV (FWHM, -particles, FPD)130-310 keV (FWHM, -particles, side)

position resolution: 1.1-1.9 mm ( -particles, FPD)0.6-1.6 mm (SF, FPD)2.0-3.5 mm ( -particles, E > 3 MeV, side)3.4-5.8 mm ( -particles, E < 3 MeV, side)

Yu.Ts. OganessianYu.Ts. Oganessian et alet al., to be published., to be published

Beam: 48Ca @ 0.7-1.1 p A (typical intensities)

Separator efficiency: DGFRS = (40±5)%

226Ra(48Ca, xn)274-xHs: experimental details


Yu.TsYu.Ts.. OganessianOganessian et alet al., to be published., to be published

Target thickness(mg/cm2)

Ebeam (MeV) E* (MeV) Beam dose1018

0.230.36

228.5 34.2-38.1 2.93.3

0.230.36

233.5 38.0-42.5 3.01.1

0.36 240.5 44.0-48.1 2.3


Hassium chemistry experiment at GSIHassium chemistry experiment at GSI238238U(U(3636S,S, xxnn))274274--xxHsHs

UNILAC GSI, DarmstadtUNILAC GSI, Darmstadt30. 04. 200830. 04. 2008 –– 14. 05. 200814. 05. 2008


Hs production and separationHs production and separation

UNILAC GSI DarmstadtUNILAC GSI Darmstadt

3636SS5+5+

EVR‘sEVR‘s

ARTESIAARTESIAtarget wheeltarget wheel

To COMPACTTo COMPACT

He/OHe/O22

Recoil chamber and ovenRecoil chamber and oven

238238UU

Target: 238U3O8 (1.8 mg/cm2, 1.6 mg/cm2, 1.5 mg/cm2)238Umetal (1.0 mg/cm2 each)

Beam: 36S5+ @ 256.4 MeV (lab) (Ityp ~ 350 pnA)

Detector: 2 x 32 PIPS diodes ( E = 50 keV FWHM)


Experimental setupExperimental setup

“COMPACT”“COMPACT”Liquidnitrogencooling

He O2

Membranepump

PTFE capillary

Drying systemRecoilchamber

Oven600 °C

Quartz woolplug

36SCu beamdump

238Utarget Be window

10 % O2

2 x 32 PIPS diodes

Overall efficiency 50 %


• Longitudinal negative temperature gradient isestablished along the thermochromatography(TC) column

• Different species borne by carrier gas areslowed down and deposited at differentpositions (temperatures) in TC columnaccording to their volatilities

• From the adsorption temperature Ta the valueof the adsorption enthalpy Hads can beevaluated

• Standard sublimation enthalpy Hsubl can beevaluated based on the empirical correlation

.

ThermochromatographyThermochromatography

Yiel

d [%

]Te

mpe

ratu

re [

°C]

25

- 150

Distance [cm] 400

TC column

Ta

Gas flow


Vacuum tight channel2x32 PIPS

1x1 cm2

“COMPACT”“COMPACT”

CryoOn-lineMultidetector forPhysicsAndChemistry ofTransactinides


3636S +S + 238238UU 274Hs*274Hs*

HsHs--chemistrychemistry -- May 2008May 2008 -- ResultsResults

EVREVR (4n) = 0,8(4n) = 0,8+2,6+2,6--0,70,7 pbpb

268Hs0.5 s*

9.58*

269Hs9.7 s

8.95, 9.13

270Hs23 s*

8.88

264Sg37 ms

266Sg360 ms

265Sg9 s 16 s

8.85 8.69

261Rf68s 3 s

8.28 8.51

274Hs*CN

4n5n6n

263Rf8 s

271Hs4 s*

9.13, 9.30

3n

267Sg80 s

8.20

09.05.200809.05.200806:22:0606:22:06

23 ms41 / -

24B / -

24T

decay chain E* = 38 MeV E* = 51 MeV

7.08 10-4 3.12 10-3

SF 4.61 10-3 1.67 10-3

SF 1.6 10-2 4.6 10-2

Random rates:t = 300 s (267Sg: T1/2 = 80 s)

8.0 MeV < E < 10.0 MeVESF > 15 MeV

E* = 51E* = 51±±3 MeV3 MeV9.02±0.08

270Hs7.6 s

9.02±0.08

266Sg

284 ms

(Dubna)

05.01.002.9


270Hs23 s*

8.88±0.05

266Sg

350 ms

266Sg23 ms

270Hs9 s*

9.02+0.05-0.1

270Hs7.6 s

9.02±0.08

266Sg

284 ms

270270HsHs summarysummary ofof experimentsexperiments::

2626Mg +Mg + 248248Cm:Cm: 3366S +S + 238238U:U: 4848CaCa ++ 226226Ra:Ra:

* log10T1/2 = a Z (Qa – Ei)-1/2 + b Z +c

A. Parkhomenko, A. SobiczewskiActa Physica Polonica 36, No. 10 (2005)


Excitation function:Excitation function: 238238U(U(3636S,S, xnxn))274274--xxHsHs

EVREVR (4n) = 0,8(4n) = 0,8+2,6+2,6--0,70,7 pbpb

Paper in preparationPaper in preparation

(Errors and limits corresponds to 68% confidence level)


Excitation function:Excitation function: 248248Cm(Cm(2626Mg,Mg, xnxn))274274--xxHsHs

J. DvorakJ. Dvorak et alet al., Phys. Rev.., Phys. Rev. LettLett.. 100100, 132503, 2008, 132503, 2008


Excitation function:Excitation function: 226226Ra(Ra(4848Ca,Ca, xnxn))274274--xxHs @ FLNRHs @ FLNR

PreliminaryPreliminary

EVREVR (4n) = 8,3+(4n) = 8,3+6,76,7--3,73,7 pbpb

Calculations: V. Zagrebaev, W. Greiner, Phys. Rev. CCalculations: V. Zagrebaev, W. Greiner, Phys. Rev. C 7878, 034610, 2008, 034610, 2008Exp. Data:Exp. Data: Yu.TsYu.Ts.. OganessianOganessian et alet al., to be published., to be published


A. GorshkovA. TürlerA. YakushevD. AckermannCh. E. DüllmannE. JägerF. P. HeßbergerJ. KhuyagbaatarJ. KrierD. RudolphM. SchädelB. SchaustenJ. DvorakH. NitscheM. ChelnokovV. ChepiginA. KuznetsovJ. EvenD. HildJ. V. KratzJ. P. OmtvedtF. SamadaniK. NishioQ. Zhi

THANK YOU!THANK YOU!

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