Synthesis of superheavyelements
Dr. Andrey G. Popeko
Flerov Laboratory of Nuclear Reactions,Joint Institute for Nuclear Research
2
Heavy Ion Physics
Staff : 310 people (including 100 younger than 35 years old) Budget: ~ 7.0 M$ Out budget staff: 110 people
The scientific activity of the FLNR in the field of heavy-ion physics develops in three main directions. They are:
Physics and chemistry investigations of the superheavynuclei with Z 112; structure and properties of the neutron reach light exotic nuclei;
accelerator technology;
heavy ion interaction with matter and applied research.
3
Periodic table of the elementsDmitri Mendeleev (1869)
4
1934: search for transurane238U + n 239U* 239Nn + e + 92 92 93
Otto Hahn und Lise Meitner
+ + +
5
1938: discovery of nuclear fission235U + 1n 236U* 90Kr + 144Ba + 1n + 1n 92 0 92 36 56 0 0
Liquid drop model
+ + + +
6
Spontaneous fission half-lives of actinides
-20
UPu
CmCf
Fm
20
10
-10
0.80 0.85Fissility
Log
T /
sSF
0.90 0.95
0LD
102
SF-isomers
HI-fusion
mfU
mfPu
mfCm
104
7
Chart of the Nuclides
SphericalShell
SphericalShell
208Pb
132Sn
298114
100Sn
40Ca
4He
48Ca
Transuranium Elements
StableElements
8
Prehistory 1966: A. Sobiczewski, F.A. Gareev, B.N. Kalinkin:
next magic numbers are Z=114, N=184; 1966: W.D. Myers, W.J. Swiatecki: next magic
numbers are Z=126, N=184 1966: V.M. Strutinsky; shell correction method 1967: H.B. Meldner: next magic numbers are
Z=114, N=184
Accuracy of predictions: Spontaneous fission half-life: T1/2 1010 !! -decay: T1/2 1010 !!
9
Synthesis of SHE at accelerators
1971; Orsay, France; 232Th + 82Kr 310126 + 4n; 4n < 0.5 mb !!!
1971-1975; Dubna, SU; deep inelastic or fission reactions of 76Ge, 136Xe + 238U
1975; Dubna, SU; 48Ca + actinides
10
Complete Fusion
11
The energy is to low
12
The energy is to high
13
The energy is correct
14
FLNR accelerators
U400M - 4m heavy ion cyclotron E = 6 100 MeV/nU400 - 4m heavy ion cyclotron E = 0.5 20 MeV/nU200 - 2m heavy ion cyclotron E = 3 15 MeV/nIC-100 - 1m heavy ion cyclotron E = 0.5 1.2 MeV/nMicrotron MT-25 - electron accelerator E = 25 MeV
15
FLNR accelerators
16
Experimental conditions
Isotopes:
+233,238 242,244 243 245,247 249 U, Pu, Am, Cm, Cf Z = 112 - 118 48Ca
beam time - 2000 h/y
beam intensity - 5.10 /s12
And detection their radioactive decay
Consumption of the mg/h 48 (68%) - 0.5
technology of the target preparation - 0.3 mg/cm2
isotope enrichment - 98-99% S2-separator
(Sarov)
Separation of super heavy nucleiDGFRS
VASSILISSAChemistry
17
On-line separation
Beam
Target
Separator
Focal plane detector
Beam stop
18
FLNR U400 cyclotron
19
UNILAC (GSI)
20
ECR - ion source
21
ECR ion source
22
Design of the superconducting (liquid He free) 18 GHz ECR ion source
Running at IC-100
23
SHIP-target
31 cm
24
Target Cooling Infra-red Snapshots
vaccum 0.6 mbar He
25
249Cf - target
26
Molten Beam Stop
27
The Velocity Filter SHIP
28
Electrostatic separator VASSILISSA
29
Dubna Gas Filled Recoil Separator
0
1
2
3
4
Targetwheel
Quadrupolelenses
Time of flight
Beam
Focal planedetector
Magneticdipole 22.5o
Dista
nce i
n metr
es
30
Research groups at DGFRS and VASSILISSA
31
Berkeley Gas-filled Separator
32
Position-Time Correlation
33
Focal plane detectors
Time-of-flight
Maindetector
Additionaldetectors, x, -, n,
34
Time-of-flight detector VASSILISSA
BEAM
MCP
1
2
foca
l pla
ne d
etec
tor
TOF 1 TOF 2
1
2
Time resolution: 300 ps (FWHM)
35
Focal plane detectors
60 mm 120 mm
36GABRIELA - Gamma Alpha Beta Recoil Investigation with the Electromagnetic Analyser
Focal plane detector GABRIELA
37
On-line neutron detector
74 3He-counters = 25 %
T (252No) = 4.43
38
SHIP-trap
39
SHIP data taking system
40
Total beam dose: 2.3.1019
248Cm + 48Ca 296 *116
Total beam dose: 1.5.1019
244Pu + 48Ca 292 *114
Strip # 5 Strip #1
4n
2
3
1
296116*
288114
292116
284112
9.81 MeV
10.56 MeV
197 MeV (195+2)
2.42 s
46.9 ms
July 19, 2000 01:21
Strip # 4
Strip # 8Strip # 2
SF
280110
9.09+0.46 MeV53.9 s
6.9 s
4n
2
3
1
296116*
288114
292116
284112
9.81 MeV
10.49 MeV
221.5 MeV
0.31 s
125.5 ms
May 02, 2001 06:21
SF
280110
9.15 MeV88.54 s
23 s
4n
2
3
1
296116*
288114
292116
284112
9.80 MeV
10.54 MeV
177 MeV
10.97 s
55 ms
May 08, 2001 16:54
SF
280110
3.15 s
9.11 MeV152.62 s
SF
2
1
288114
284112
280110
9.80 MeV
9.13 MeV
213 MeV (171+42)
4.58 s
18.0 s
7.4 s
SF
4n
2 2
1
292114*
288114
284112
280110
9.87 MeV
9.21 MeV
221 MeV (156+65)
0.77 s
10.3 s
14.3 s
June 25, 1999 05:39 Oct. 28, 1999 22:24
4n
292114*27.8 mm
28.3 mm
27.9 mm
28.5 mm
19.2 mm
19.5 mm
19.2 mm
19.8 mm
19.6 mm
20.7 mm
20.8 mm
20.3 mm
20.4 mm
20.6 mm
11.8 mm
11.4 mm
11.5 mm
30.5 mm
30.6 mm
30.1 mm
30.6 mm
11.7 mm
The beam was switched off
41
Charts of transactinide nuclides
1984 1996
42
Chart of transactinide nuclides 2006
43
Methods of identification:
generic decay links; cross-bombardments; on-line post separator; quasi-on-line mass analyzer; calorimetric detectors; Ge-- detectors; ion traps.
We need higher production rates!
44
Chemistry and masspectrometry
25
20
030 35 40
40
60
80
100
120
45 50
xn
(ar
b. u
nit
s)
E* (MeV)
2n
3n4n
1.5 mg/cm20.3 mg/cm2
45
Ar +CH4mixture
48Ca
Heinlet
Heoutlet
He
Gasoutlet
Chemical isolation of the element 112
Target:U3O8- 2mg/cm2 + Nd2O3 - 50 g/cm2
Beam:48Ca (262 MeV)0.6 pA
115288
R
10.46 MeV125 ms
1
113284
9.75 MeV5.2 s
Mt276
3
9.71 MeV1.03 s
Bh272
4
0.69 s111
280
210. MeV00
23.1 hr
SF205 MeV
Decay chain of 268 Db observed with Dubna Gas-filled Recoil Separator in 243Am + 48Ca reaction
Decay chain of 268 Db observed with Dubna Gas-filled Recoil Separator in 243Am + 48Ca reaction
14.14 s
5 9.02 MeV
Db268
47
Irradiation of 243Am-target with 48Ca-ions
48
Taking off thin layer of Cu-catcher(100150 mg of Cu)
49
Detection system
50
Fission fragment Total Kinetic Energy300
250
200
150
100
50
00 500 1000 1500 2000
Tran
slat
iona
l Kin
etic
Ene
rgy
(MeV
)
Z /A2 1/3
Yukawa + Exponential Nuclear EnergyTwo - body viscosity
(TP) = 0,0000.010
0.020
Z=88
94
102
106
112
118A.J. Sierk and J.R. Nix, Phys.Rev. C 21 (1980) 982
51
Total Kinetic Energy distributions of252Cf and 268Db
0 20 40 60 80 100 120 140 160 180 200 220 240 2600
20
40
60
80
100
120C
ount
s
TKE / MeV
52
Average numbers of prompt neutrons emitted in spontaneous fission
90 92 94 96 98 100 102 104 106 108 110 112 114 116 118 120 122
2
3
4
5
6
7
8
9
10
11
12
Z
Target (238U, 242Pu; 1 mg/cm2)
Beam (48Ca; 233-239 MeV)
Beamstop
SiO2-FilterTa metal850C
Quartzcolumn
CryoCryo OnOn--lineline DetectorDetector (4(4 COLD)COLD)
Carrier gas He/Ar (70/30)
Capillary with 2 s transport time
(32 pairs PIN diodes, one side gold covered)
HgHg LoopTemperature gradient: 35C to 184 C
T
l
RnRn
ChemistryChemistry of of thethe elementselements 112 & 114112 & 114
112112Recoilchamber
Quartzinlay
54
Periodic table of the elements (2006)
55
Mass Analyzer of Super Heavy Atomsm/m=1000
Ion source
Ion beam
Target
V = 40 0 V
Magnetic mass-analyser
Hot catcher 2000=
Detectors
56
Mass Analyzer of Super Heavy Atoms(MASHA)
57
MASHA test with Xe and Hg isotopes
mass, a.m.u.128 129 130 131
54XeM =3071/ M
0.04 a.m.u.
21.2%
3.9%2%
I,nA
26 %.4
mass, a.m.u.195 196 197 198 199 200 201 202 203 204 205
0.01
0.1
1
10
10080Hg
M/M= 7127
0.0 a.m.u.7
29.7%
6.8%
23.1%16.9%
10.1%
0.15%
13.2%
I,nA
58
Search for SHE in Nature
Search for SHE in terrestrial matter Search for SHE in meteorites Search for SHE in cosmic rays Investigation of isotopic anomalies
20 years Void result,
but many new high sensitive detection methods were developed
59
Search for SF of natural Eka Os by detection of fission neutrons
150 160 170 180 190140
15
20
10
5
0
-5
-10
116
116
118
112
112
114
114
110
110
108
108
Neutron number
- decay
DeformedShell
SphericalShell
Log
T (s
econ
ds)
Age of the Earth
stablenuclei
60
Detector installed in Modana(France)
FrFrjus peakjus peak
ModaneModane
Entrance to Entrance to thethe roadroad tunneltunnel
France
61
RIB Accelerator Complex of the FLNR
+ + + +
+
+
,
-400
V 50 f = 2000
Kr, Xe0,5 6 /
Principle of Track Membrane Production
++
Scanning Ion BeamsScanning Ion Beams
Polymer FilmPolymer Film
Vacuum Ion Beam LineVacuum Ion Beam LineFrom From
acceleratoraccelerator
63
TRACK MEMBRANES
PARALLELPARALLELCYLINDRICALCYLINDRICAL
PORESPORES
NONNON--PARALLELPARALLELCYLINDRICALCYLINDRICAL
PORESPORES
CIGARCIGAR--LIKE PORESLIKE PORES BOWBOW--TIE PORESTIE PORES
MICROWELL: TOP VIEW
CROSS-SECTION OF MICROWELL:- 12 m IN DIAMETER- 35 m IN DEPTH
65
Nano-structures
66
Thank you for your attention!
Synthesis of superheavy elementsHeavy Ion PhysicsPeriodic table of the elementsDmitri Mendeleev (1869) 1934: search for transurane1938: discovery of nuclear fissionSpontaneous fission half-lives of actinidesChart of the NuclidesPrehistorySynthesis of SHE at acceleratorsComplete Fusion The energy is to low The energy is to high The energy is correctFLNR acceleratorsFLNR acceleratorsExperimental conditionsOn-line separationFLNR U400 cyclotronUNILAC (GSI)ECR - ion sourceECR ion sourceDesign of the superconducting (liquid He free) 18 GHz ECR ion sourceSHIP-targetTarget Cooling Infra-red Snapshots249Cf - targetMolten Beam StopThe Velocity Filter SHIPElectrostatic separator VASSILISSA Dubna Gas Filled Recoil Separator Research groups at DGFRS and VASSILISSABerkeley Gas-filled SeparatorPosition-Time CorrelationFocal plane detectorsTime-of-flight detector VASSILISSAFocal plane detectorsOn-line neutron detectorSHIP-trapSHIP data taking systemCharts of transactinide nuclides 19841996Chart of transactinide nuclides 2006Methods of identification:Chemistry and masspectrometryIrradiation of 243Am-target with 48Ca-ionsTaking off thin layer of Cu-catcher(100150 mg of Cu)Detection systemFission fragment Total Kinetic EnergyTotal Kinetic Energy distributions of252Cf and 268Db Average numbers of prompt neutrons emitted in spontaneous fissionMass Analyzer of Super Heavy AtomsDm/m=1000Mass Analyzer of Super Heavy Atoms(MASHA)MASHA test with Xe and Hg isotopesSearch for SHE in NatureSearch for SF of natural Eka Os by detection of fission neutronsDetector installed in Modana(France)RIB Accelerator Complex of the FLNRNano-structuresThank you for your attention!