Spontaneous Fission of $^{256}$Rf, New Data Svirikhin, A.I.; Yeremin, A.V.; Izosimov, I.N. ...
Physics of particles and nuclei letters,
07/2016, Letnik:
13, Številka:
4
Journal Article
Recenzirano
Spontaneous fission properties of the short-lived neutron-deficient 256Rf nucleus produced in thecomplete fusion reaction with a beam of multiply charged heavy 50Ti ions from the U-400 cyclotron ...(FLNR,JINR) are experimentally investigated. Its half-life and decay branching ratio are measured. The averagenumber of neutrons per spontaneous fission of 256Rf ( = 4.47 ± 0.09) is determined for the first time.
Fine structure in the alpha decay of $^{224}$U Lopez-Martens, A.; Hauschild, K.; Rezynkina, K. ...
The European physical journal. A, Hadrons and nuclei,
2014, Letnik:
50
Journal Article
Recenzirano
224U nuclei were populated in fusion-evaporation reactions using a 206Pb target and an intense 22Ne beam. Fusion-evaporation residues were separated by the new separator SHELS at the FLNR, Dubna and ...implanted into a large-area double-sided silicon strip detector. Position- and time-correlated alpha decays were used to identify evaporation residues. A new α -decay line at 8095(11) keV was observed in this work and assigned as the decay from 224U to the first excited 2+ in the daughter nucleus 220Th. Coincident photons were also observed allowing to unambiguously determine the excitation energy of the first excited 2+ state in 220Th to be 386.5(1) keV and not 373.3(1)keV as previously reported. The half-life of 224U was measured to be 396(17)μs.
In this paper, the search for new decay chains of oganesson isotopes is presented. The experiment utilized the Dubna Gas Filled Recoil Separator and a highly segmented recoil-decay detection system. ...The signals from all detectors were analyzed in parallel by digital and analog data acquisition systems. For the first time, a target of mixed californium (51% $^{249}\mathrm{Cf}$, 13% $^{250}\mathrm{Cf}$, and 36% $^{251}\mathrm{Cf})$ recovered from decayed $^{252}\mathrm{Cf}$ sources was produced and irradiated with an intense $^{48}\mathrm{Ca}$ beam. The observation of a new decay chain of $^{294}\mathrm{Og}$ is reported. Finally, the prospects for reaching new isotopes $^{295,296}\mathrm{Og}$ are discussed.
In this paper, the search for new decay chains of oganesson isotopes is presented. The experiment utilized the Dubna Gas Filled Recoil Separator and a highly segmented recoil-decay detection system. ...The signals from all detectors were analyzed in parallel by digital and analog data acquisition systems. For the first time, a target of mixed californium (51% $^{249}\mathrm{Cf}$, 13% $^{250}\mathrm{Cf}$, and 36% $^{251}\mathrm{Cf})$ recovered from decayed $^{252}\mathrm{Cf}$ sources was produced and irradiated with an intense $^{48}\mathrm{Ca}$ beam. The observation of a new decay chain of $^{294}\mathrm{Og}$ is reported. Finally, the prospects for reaching new isotopes $^{295,296}\mathrm{Og}$ are discussed.
With the aid of the Geant4 Monte Carlo simulation package a new detection system has been designed for the focal plane of the recoil separator VASSILISSA situated at the Flerov Laboratory of Nuclear ...Reactions, JINR, Dubna.
GABRIELA (
Gamma
Alpha
Beta
Recoil
Investigations with the
ELectromagnetic
Analyser VASSILISSA) has been optimised to detect the arrival of reaction products and their subsequent radioactive decays involving the emission of
α
- and
β
-particles, fission fragments,
γ
- and X-rays and conversion electrons. The new detector system is described and the results of the first commissioning experiments are presented.
An experiment on the study of the
246
Fm spontaneous fission was conducted using the SHELS separator. The isotope was synthesized in the complete fusion reaction of
40
Ar beam ions and
208
Pb target ...nuclei. The neutron yields of
246
Fm spontaneous fission (
ν
¯
=
3.79
±
0.30
,
σ
ν
2
=
2.1
) were obtained using the SFiNx detector system. The multiplicity distribution of emitted prompt neutrons was restored using the Tikhonov method of statistical regularisation (
ν
¯
r
=
3.79
±
0.20
,
σ
ν
r
2
=
2.8
). The spontaneous fission branching ratio (
b
SF
=
0.061
±
0.005
) and the half-life (
T
1
/
2
=
1
.
50
-
0.07
+
0.08
s) of the isotope were determined. The experimental data were compared with scission point model predictions. An agreement was observed in the average number of neutrons per spontaneous fission process. However, the forms of the experimental and model prompt neutron multiplicity distributions differ significantly.
Characteristics of spontaneous fission of 250No Svirikhin, A. I.; Andreev, A. V.; Yeremin, A. V. ...
Physics of particles and nuclei letters,
2017/7, Letnik:
14, Številka:
4
Journal Article
Recenzirano
This study describes an experiment on investigating the properties of spontaneous fission of shortlived neutron-deficient nuclei synthesized in the reaction of complete fusion
48
Ca +
204
Pb =
252
...No*. The experiment is performed using the SHELS separator and the beam of multicharged ions at U-400 accelerator (LNR, JINR). Two activities undergoing spontaneous fission, which can be related to the ground and isomeric states of
250
No nucleus, are registered. The half-lives, total kinetic energies of fission fragments, and neutron multiplicities are measured for the short-lived nuclei. The average number of neutrons per fission for the activity with
t
1/2
= 5.1 ± 0.3 μs is = 4.38 ± 0.13 μs, and for nuclei with the half-life
t
1/2
= 36 ± 3 μs it is xxxxx.
The problem of studying the spontaneous fission of nuclei from the exotic region of short-lived neutron-deficient isotopes with
Z
≥ 100 is considered. A combined detecting system is created in the ...focal plane of the VASSILISSA separator. The main part of this system is a neutron detector that allows us to measure the yields of spontaneous fission neutrons from nuclei produced in a total fusion reaction with heavy ion beams in the on-line mode. This procedure is used for the first time to acquire data on the emission of spontaneous fission neutrons from short-lived
244,246
Fm isotopes. Data gathered earlier for
252
No isotopes are refined in the scope of this work.
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