Transcript FLEROV LABORATORY of NUCLEAR REACTIONS

Programme Advisory Committee for Nuclear Physics
33th meeting, 20-21 January 2011
FLNR Radiochemical Research.
Present Status and 7-year Plan
S. Dmitriev
Identification and Study of Chemical
Properties of New Elements of the
Mendeleev Periodic Table
2
CHEMISTRY OF TRANSACTINIDES
(Z>103)
 1966 – I.Zvara et al. – Gas-phase Chemistry
IV
V
VI
Hf
Ta
W
104
105
106
HfCl4
104Cl4
TaBr5
105Br5
WO2Cl2
106O2Cl2
3
5
40Zr
41Nb
42Mo
43Tc
44Ru
45Rh
46Pd
47Ag
48Cd
6
72Hf
73Ta
74W
75Re
76Os
77Ir
78Pt
79Au
80Hg
7
104Rf
105Db
106Sg
107Bh
108Hs
109Mt
110Ds
111Rg
Cn
RfCl4
DbCl5
SgO2Cl2
BhO3Cl
HsO4


RfBr4
DbBr5
261Rf()
262,263Db()
266Sg(,SF)
267Bh()
269Hs()
78 s
30 s
21 s
17 s
9.7 s

268Mt()
271Ds()
272Rg()
21 ms
1,6 ms
3,8 ms

277Cn()
0.69 ms
4
Number of observed decay chains
Element 118
3
Element 116 26
Element 115
4
Element 114 43
Element 113
2
Element 112
8
Relatively long half-lives of isotopes of
elements 104-116 produced in reactions with
48Ca and chemical properties of SHE
predicted theoretically permit new
experiments aimed at:
 the chemical identification of SHE,
 study of their chemical properties,
 determination of masses of the SHE isotopes
Of-line chemical
separation of 268Db
He box (1 tor)
Dmitriev S N et al., Mendeleev Commun.15 (2005) 1
Schumann D et al., Radiochim. Acta 93 (2005) 727
Stoyer N J et al., Proc.9th Int.
R
Conf. NN Collisions,Brazil,
28 Aug.–1 Sep. 2006.
288
1
Oganessian Yu Ts et al.,
Phys. Rev. C 69 (2004) 021601
284
2
280
3
276
4
272
5
Bh
Mt
111
113
catcher of
recoiling atoms
12.5
beam
115
10.46 MeV
125 ms
rotating
10.00 MeV
0.69 s
0.
rotating
entrance window
243Am-target
9.75 MeV
5.2 s
~20 s
9.71 MeV
1.03 s
9.02 MeV
14.14 s
78-3He - neutron
detector
268
Db
SF
205 MeV
23.1 h
Nb / Ta / Db - fraction
4 - fission
fragment
detectors
0
48Ca
N Sample
(data)
tirr
hr
1 (12.06)
20
+
243Am
1
Beam
Dose
Ebot+Etop+ n (t,c)
2,51017
120+126+2 n (5;64)
0
1
tdetect
hr
tmeasurement
hr
20
429
74
186
15
72
385
0
2 (13.06)
22
3,71017
̶ +86+11n (57)
0
3 (14.06)
22
3,41017
1
131+124+1 n (3)
1 0
116+122+2 n (8;16)
0
4 (15.06)
5 (17.06)
22
38
2,91017
6,71017
104+120+11n (2)
1 0
97+125+1 n (151)
0
100+128+11n (89)
0
358
117+118+21n (6,98)
108+107+31n0 (4,31,43)
1
0
110+104+0
n
1
0
--+76+2 n (6,41)
6
9
15
68
120+114+21n (2,2)
39
933
-
957
5
93
174
910
0
23
3,91017
7 (19.06)
22
3,61017
-
8 (21.06)
45
7,41017
119+110+2 n (5;33)
118+105+21n0 (72,165)
65+58+31n 0(12,19,29)
6 (18.06)
22
29
51
861
0
1
0
 3,4.1018
15 events
10
T1/2 = =
29 32
h h
T
1/2
100
E1 (MeV)
1
1
50
E
1/
E
2
=
(N=163)
15 events
events
15
Counts / 10 hours
Spontaneous fission
half-life of 268Db
150
0.1
100
0
200
300
time (hours)
0
0
50
10
268Db
Counts
QF ~ 280 MeV
 = 4.2
6
Counts / 10MeV
252Cf
5
100
E2 (MeV)
150
230 MeV
4
2
0
0
0
2
3
4
1
Multiple coincidence
5
0
100
200 9
TKE (MeV)
300
Mendeleev periodic table of the elements (2010)
GAS PHASE CHEMISTRY WITH
ELEMENTS 112 AND 114

Are elements 112 and 114
volatile metals?

How do relativistic effects
influence the chemistry of E112
and of E114?
11
Relativistic effects
m  m0 / (1  (v / c)
Re(7s) = 20%
2
a0  4 0  / me
2
2
scale as ~ Z2

contraction and stabilization
of s and p1/2 orbitals
1
nr

expansion and
destabilization of d and f
orbitals
SO splitting of p, d, f
orbitals
j=ls
7s
112
-7
E, eV

rel
-3
6d5/2
-11
7s1/2
-15
6d
-19
-23
6d3/2
How to determine experimentally a metallic
character of a volatile element at a single atom
level?
→ Determine interaction energy (adsorption
enthalpy) with noble metals (e.g. Au)
→ If metallic: strong interaction (adsorption
enthalpy) if non-metallic (noble gas like):
weak interaction
13
Compound Hg(Au)
Reaction:
242Pu(48Ca,3n)287114[0.5s]→α→283112[3.6s]
and 112(Au)
The Observation Dubna 2006/2007
Oganessian et al. 2004
6.3 ms
Experiments with element 112
Reported at FLNR:
291116
10.7 MeV
287114
287114
5 weeks: 6*1018 of 48Ca
242Pu (48Ca,
287114
3n) 287114
287114
287114
Observed in Chemistry:
0.51 s
10.02 MeV
on ice
on gold
283112
283112
283112
283112
283112
283112
4s
-24°C
-5°C
-26°C
-44°C
-126°C
9.54 MeV
9.35 MeV
9.52 MeV
9.37 MeV
9.48 MeV
9.52 MeV
279Ds
279Ds
279Ds
279Ds
279Ds
279Ds
0.18 s
SF(>90%)
205 MeV
: 0.773 s
SF
: 0.088 s
SF
: 0.072 s
SF
: 0.592 s
SF
: 0.536 s
SF
85+12 MeV
112+n.d. MeV
94+51 MeV
108+123 MeV
127+105 MeV
Eichler, R. et al. Nature (2007)
Gold
Element
30
1
4
12
16
20
Detector number
Relative yield %

112
_0.12 MeV
9.47 +
279
>3
s
110
on gold
SF 232 MeV
0.59 s
30
Hg
20
Relative yield %
1
4

50
Gold
0
Ice
-50
Rn
-100
16
20
Detector number
279
9.52 MeV
on gold
20
Hg
110
SF
112+F2 MeV
0.07 s

279
112
8

9.35 MeV
112
4
28
32
12
-200
50
283
110 on gold
SF 85+12 MeV
0.77 s
10
1
24
room temperature
Ice
283
112
-200
-150
12
8
40
30
0
C
32
112
50
0
28
24
283
10
gas flow 1.5 l/min
-100
-150
8
40
0
-50
Rn
50
gas flow 0.89 l/min
112 is a noble metal – like Hg
112
10
He/Ar + Hg + Rn
0
Ice
Hg
20
0
50
Temperature 0C
Relative yield %
40
Hg
Rn
Temperature
112
_0.12 MeV
279
9.38 +
>3
s
110
on gold
SF 231 MeV
0.53 s
50
gas flow 0.86 l/min
283
16
20
Detector number
283
0
112
9.52 MeV
110
SF >140 MeV
0.09 s
-50
279
Rn
-150
on ice!
24
28
-100
32
-200
Temperature 0C

48Ca
+
242Pu
Chemistry
DGFRS
287114
287114
0.51 s
10.02 MeV
10.04 MeV
283112
283112
4.0 s
10.9 s
9.54 MeV
279Ds
0.18 s
SF
Тads= -88 °C
9.53 MeV
279Ds
0.24 s
SF
17
48Ca
+
244Pu
Chemistry
DGFRS
288114
288114
0.8 s
9.95 MeV
9.95 MeV
284112
101 ms
SF
284112
Тads= -84 °C
:109 ms
SF
18
Result from the chemistry experiment with
element 114
→ Element 114 exhibits a very weak interaction
with Au - pointing to a physisorptive
interaction (similar to a noble gas).
→ A quantitative description of this behaviour is
lacking so far.
19
The results obtained up to 2010 (synthesis
of new elements with atomic numbers
113, 114, 115, 116 and 118, investigation
of their nuclear and chemical properties,
first experimental observation of the
influence of relativistic effects on the
chemical behavior of SHE) served as a
starting for the new 7-year program
for 2010 – 2016.
FLNR main directions of studies
according to the JINR 7-year plan (2010-2016)
1. Synthesis of superheavy elements and study of their properties;
2. Chemistry of SHE;
3. Investigation of spontaneous and induced fission;
4. Mass-spectrometry and nuclear spectroscopy of isotopes of
heavy and transfermium elements;
5. Study of mechanisms of reactions with stable and radioactive
nuclei;
Accelerator operation time in the 2010:
U400
6320 hours
U400M
4570 hours
Synthesis of a new element with atomic number Z=117
Yu. Ts. Oganessian,1) F. Sh. Abdullin,1) P. D. Bailey,2) D. E. Benker,2)
M. E. Bennett,3) S N. Dmitriev,1) J. G. Ezold,2) J. H. Hamilton,4) R. A. Henderson,5)
M. G. Itkis,1) Yu. V. Lobanov,1) A. N. Mezentsev,1) K. J. Moody,5) S. L. Nelson,5)
A.N. Polyakov,1) C. E. Porter,2) A. V. Ramayya,4) F. D. Riley,2) J. B. Roberto,2)
M. A. Ryabinin,6) K. P. Rykaczewski,2) R. N. Sagaidak,1) D. A. Shaughnessy,5)
I.V. Shirokovsky,1) M. A. Stoyer,5) V. G. Subbotin,1) R. Sudowe,3) A. M. Sukhov,1)
Yu. S. Tsyganov,1) V. K. Utyonkov,1) A. A. Voinov,1) G. K. Vostokin,1)
and P. A. Wilk5)
1 Joint Institute for Nuclear Research, RU-141980 Dubna, RF
2 Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
3 University of Nevada Las Vegas, Las Vegas, NV 89154, USA
4 Vanderbilt University, Nashville, TN 37235, USA
5 Lawrence Livemore National Laboratory, Livermore, CA 94551, USA
6 Research Institute of Atomic Reactors, RU-433510 Dimitrovgrad, RF
(Dated: April 1, 2010)
The discovery of a new chemical element with atomic number Z=117 is reported. The isotopes
293117 and 294117 were produced in fusion reactions between 48Ca and 249Bk. Decay chains
involving eleven new nuclei were identified by means of the Dubna Gas Filled Recoil Separator.
The measured decay properties show a strong rise of stability for heavier isotopes with Z≥111,
validating the concept of the long sought island of enhanced stability for super-heavy 22
nuclei
Chemistry of the Element 113
249Bk
21 ms
293
10 ms
+ 48Ca
α2
10.31(9) MeV
10.48 MeV
7.9 s 285
1.2 s
Rg
0.023 s
290
1.0 s
115
α2
281
α1
11.03(8) MeV
11.26 MeV
0.32 s
289
0.22 s
α3
117
117
α1
112 ms
294
45 ms
297
28.3 s 286
16 s
113
α3
9.74(8) MeV
9.48(11) MeV
9.96 MeV
0.74 s
8.1 s
11.0 s
13 s
TKE = 218(5) MeV
38 s
α5
α6
270
274
278
10.81(10) MeV
11.00 MeV
115
243Am
3n
+ 48Ca
α2
9.63(10) MeV
9.56 MeV
280
α3
9.00(10) MeV
9.43 MeV
276
Mt
α4
9.55(19) MeV
9.14 MeV
272
α5
268
Db
Db
SF
SF
115
10.46 MeV
87 ms
284
113
8.80(10) MeV
8.43 MeV
288
α1
9.95(40) MeV
10.23 MeV
Bh
TKE = 219(5) MeV
33.4 h
117
117
Rg
α4
SF
1.3 min
7.4 min
282
297
113
10.00 MeV
0.48 s
Rg
9.75 MeV
3.6 s
Mt
9.71 MeV
0.72 s
Bh
9.02 MeV
9.8 s
TKE = 205(5) MeV
16 h
DGFRS
23
CHEMISTRY OF THE 113 ELEMENT
Target (249 Bk;
0,5 mg/cm2)
SiO2Ta
800°C
(4)
Au - 113
16 pairs
2.5m
He/Ar (70/30)
1 L/min
24
16 pairs of gold covered detectors
25
48Ca
Target
48Ca
+ 249Bk
249Bk
(0.5 mg∙cm-2)
natNd (30 μg∙cm-2)
Emid. target = 252 MeV
I ~ 9 eμA
Irradiation: - 18.04.2010 – 31.05.2010;
target I - 3.5∙1018 ; target II - 5.6∙1018
9.1∙1018
26
Alpha and SF spectra
10
4
10
4
Po-211
Po-211
Alpha Bk-target I
Detector #8
Counts
10
9.0 ± 0.1 MeV
849 events
3
Alpha Bk-target II
Detector #4
10
9.0 ± 0.1 MeV
879 events
3
9.6 ± 0.1 MeV
52 events
Po-212
10
2
10
1
10
0
10
2
10
1
10
0
10
3
9.6 ± 0.1 MeV
54 events
Po-212
9.5 ± 0.1 MeV
67 events
7
10
8
9
10
11
3
12
9.5 ± 0.1 MeV
78 events
7
8
9
10
Counts
10
2
10
2
10
1
10
1
10
0
10
0
Db-270
100
12
Fission Bk-target II
Detector #4
Fission Bk-target I
Detector #8
50
11
Db-270
150
Energy, MeV
200
50
100
150
Energy, MeV
200
27
112 ms
294
45 ms
α1
0.023 s
290
1.0 s
E* = 35 MeV
1 event
28.3 s
16 s
α3
0.74 s
282
8.1 s
α4
11.0 s
13 s
α5
1.3 min
7.4 min
α
270
6
274
278
115
α2
249Bk
9.00(10) MeV
9.43 MeV
Bot. 8
α3
Mt
Bot. 8
9.55(19) MeV
9.14 MeV
α4
Bot. 8
α5
270
Db
249Bk
3n
+
48Ca
Bh
278
Mt
282
α2
286
SF
101.0 + 89.1 MeV
79.25 h
04 May 2010 10:05:46
Bk-target I
115
286
113
α3
9.62 MeV
Top 4
α4
8.89 MeV
64.90 s
8.77 MeV
13.59 min
117
290
115
Rg
9.52 MeV
6.49 s
294
α1
290 1
α2
274
294
α 117
Rg
α6
DGFRS
3n
+
48Ca
9.63(10) MeV
9.56 MeV
Bot. 8
TKE = 219(5) MeV
33.4 h
10.81(10) MeV
11.00 MeV
113
8.80(10) MeV
8.43 MeV
SF
117
9.95(40) MeV
10.23 MeV
286
Bh
Db
117
297
278
α5
Bot. 4
α6
270
Db
Mt
113
282
Rg
9.01 MeV
1.85min
274
Bh
8.64 MeV
<1.42 min
SF
98.6 + 88.5 MeV
64.61 h
16 May 2010 02:29:54
Bk-target II
28
Hg-185 DISTRIBUTION
50
Bk-target II
Ca48Bk17.000 - start
18
Ca48Bk17.031 - integral 1.30x10
18
Ca48Bk18.001 - integral 2.66x10
18
Ca48Bk18.035 - integral 4.33x10
18
Ca48Bk18.062 - integral 5.62x10
Hg-185
Relative activity, %
40
30
20
10
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Detector #
29
Experimental program of 2011-2012

Chemistry of 113 element (243Am + 48Ca)

Chemistry of 112 and 114 elements (242Pu + 48Ca)

Chemistry of 105 element (243Am + 48Ca)(off-line)
New Set-ups for Radiochemistry
according to the 7-year plan (2010-2016)
1. Pre-separator (background, short lived isotopes);
2. New detector systems (max. information from single event);
3. New high beam current targets;
4. New radiochemical laboratory, II class (targets preparation,
chemistry of long-lived SHE).
Experiments with element 114
D
Q2
COLD
10°C
Pu (48Ca, 3-4n) 288-289114
Recoil ranges tested with:
206Rn, 185Hg, 254No
 Reliable design:
3 m Mylar, 1.5 cm Ar (1 bar)
Q1
Gas flow:
Ar 2.1 l/min
ttrans~1.4 s
400g/cm2
244Pu
244
-160°C
Preliminary Results
Dubna 2007/2008
No preseparation
DGFRS preseparation
100
1000000

100000
#/ 20 keV
#/20keV
10000
1000
100
10
10
1
1
8
10
12
14
16
18
E, MeV
20
22
24
26
8
10
12
14
16
18
20
22
24
E, MeV
Factor ~2-3 loss in overall efficiency:
thin targets (2-3)
transmission of a separator (3)
New FLNR gas-filled separators
“chemical”
“physical”
Reaction
Transmission
244Pu(48Ca,3n)289114
60 %
244Pu(58Fe,4n)298120
75 %
Detectors for chemical studies
carrier gas
Clover γ - detectors
cryo-on-line-detector
Si (α,SF) - detectors
combined α-, γ-, SF- detector
NEW EXPERIMENTAL HALL
New Set-ups for Radiochemistry
according to the 7-year plan (2010-2016)
1. Pre-separator (background, short lived isotopes);
2. New detector systems (max. information from single event);
3. New high beam current targets;
4. New radiochemical laboratory, II class (targets preparation,
chemistry of long-lived SHE).
Creation of set-ups will be synchronized with the construction
of the new experimental hall and accelerator.
THANKS FOR YOUR
ATTENTION!
Efforts focused on the synthesis of SHE
New ECR-ion source
(GANIL, JINR)
ACCELERATORS
ISOTOPE
ENRICHMENT
Enrichment up to 68-70%
(Lesnoy)
beam
12
intensity - 4 - 8 .10 /s
48Ca
beam time - 4000 h/y
TARGET TECHNOLOGY
Isotopes:
U[233, 238], Pu[242, 244], Am[243], Cm[245, 248], Cf[249] +
technology of the target
preparation – 0.3 mg/cm2
isotope enrichment 98-99%
S-2 separator
(Sarov)
48
Z = 112 - 118
Separation and detection of
superheavy nuclei
New separator & detectors
New target matter
REACTOR
REGIME
Ca
isotope production
high flux reactors
(Oak Ridge, Dimitrovgrad)
(Dubna, Livermore)
NEW
RECOIL
SEPARATOR
39
Cold & hot fusion cross sections
-30
1n
Cold fusion
208Pb, 209Bi + 48Ca, 50Ti,...70Zn
4n
Hot fusion
Actinides + 22Ne, 26Mg,...34S
Cross sections (cm2)
10
-32
10
Actinides + 48Ca
4n-3n
-34
10
fusion
survival
-36
10
SHE
-38
10
102 104 106 108 110 112 114 116 118 120
Atomic number
40