Search results for "FISSION"
showing 10 items of 421 documents
Interligand Electron Transfer Determines Triplet Excited State Electron Injection in RuN3−Sensitized TiO2 Films
2004
Electron injection from the transition metal complex Ru(dcbpy)(2)(NCS)(2) (dcbpy = 2,2'-bipyridine-4,4'-dicarboxylate) into a titanium dioxide nanoparticle film occurs along two pathways. The dominating part of the electron injection proceeds from the initially excited singlet state of the sensitizer into the conduction band of the semiconductor on the sub-hundred-femtosecond time scale. The slower part of the injection occurs from the thermalized triplet excited state on the picosecond time scale in a nonexponential fashion, as was shown in a previous study (Benko, G.; et al. J. Am. Chem. Soc. 2002, 124, 489). Here we show that the slower channel of injection is the result of the excited s…
Beta Decay of 111Tc to 111Ru
1998
The β-decay of the very neutron-rich 111Tc nucleus has been observed. A partial decay scheme of 111Ru is presented, complementing the high-spin levels earlier reported in spontaneous fission work.
New design and simulation of the ion guide for neutron-induced fission products at the IGISOL facility
2023
Measurements of independent fission yield distributions in neutron-induced fission at high neutron energies are important for our fundamental understanding of the fission process, and are also relevant for reactor physics applications. So far, measurements of independent fission yields in proton-induced fission have been performed at the IGISOL facility at the University of Jyväskylä, using the Penning trap as a high resolving-power mass-filter. In order to also facilitate measurements of neutron-induced fission, a dedicated ion guide and a proton-to-neutron converter was developed. However, the first measurement indicates that fewer fission products than expected reach the Penning trap. To…
Asymmetric and symmetric fission of excited nuclei of Hg180,190 and Pb184,192,202 formed in the reactions with Ar36 and Ca40,48 ions
2021
Background: Observation of asymmetric fission of $^{180}\mathrm{Hg}$ has led to intensive theoretical and experimental studies of fission of neutron-deficient nuclei in the lead region.Purpose: The study of asymmetric and symmetric fission modes of $^{180,190}\mathrm{Hg}$ and $^{184,192,202}\mathrm{Pb}$ nuclei.Methods: Mass-energy distributions of fission fragments of $^{180,190}\mathrm{Hg}$ and $^{184}\mathrm{Pb}$ formed in the $^{36}\mathrm{Ar}+^{144,154}\mathrm{Sm}$ and $^{40}\mathrm{Ca}+^{144}\mathrm{Sm}$ reactions, respectively, at energies near the Coulomb barrier have been measured using the double-arm time-of-flight spectrometer CORSET and compared with previously measured $^{192,20…
Neutron yield from a thick target irradiated by 90MeV protons
2005
In the context or the design of an intense source of low and intermediate energy, neutrons, the angular and energy distributions of neutrons produced in the interaction of 90 MeV protons in a C-12 target, in which the protons are stopped, have been measured by time-of-flight and activation techniques, As compared to C-12 the yield is less than a factor two higher, while it is somewhat less than for a Be-9 target. (c) 2005 Elsevier B.V. All rights reserved.
Low-energy fission investigated in reactions of 750 AMeV 238U-ions with Pb and Be targets
1996
Charge distributions of fragments from low energy nuclear fission are investigated in reactions of highly fissile238U projectiles at relativistic energies (750 A·MeV) with a heavy (Pb) and a light (Be) target. The fully stripped fission fragments are separated by the Fragment Separator (FRS). Their high kinetic energies in the laboratory system allow the identification of all atomic numbers by using Multiple-Sampling Ionization Chambers (MUSIC). The elemental distributions of fragments observed at larger magnetic rigidities than the238U projectiles show asymmetric break-up and odd-even effects. They indicate a low energy fission process, induced mainly by dissociation in the electro-magneti…
First isomeric yield ratio measurements by direct ion counting and implications for the angular momentum of the primary fission fragments
2018
We report the first experimental determination of independent isomeric yield ratios using direct ion counting with a Penning trap, which offered such a high resolution in mass that isomeric states could be separated. The measurements were performed at the Ion Guide Isotope Separator On-Line (IGISOL) facility at the University of Jyvaskyla. The isomer production ratios of Ge-81, Y-96,Y-97 Sn-128(,1)30, and Sb-129 in the 25-MeV proton-induced fission of U-na(t) and Th-232 were studied. Three isomeric pairs (Ge-81, Y-96, and Sb-129) were measured for the first time for the U-na(t)(p, f) reaction, while all the reported yield ratios for the Th-232(p, f) reaction were determined for the first ti…
First decay scheme of 113Tc and identification of 113Ru m
1998
Very neutron–rich fission products of the mass chain A=113 obtained from the IGISOL on–line mass separator have been investigated by γγ coincidence techniques and γ-spectra multiscaling. Gamma–rays following β–decay of 113Tc have been observed for the first time and a new 0.5 s isomeric state has been found in 113Ru.
A system for rapid radiochemical separations from aqueous solutions
1969
Abstract For the study of short-lived fission products, an automatic system has been developed that allows to irradiate aqueous solutions sealed in polystyrene capsules, to separate chemically the radioactive products formed, and to start counting, all within a few seconds. Irradiations are performed in a pneumatic tube system installed in a horizontal beam hole of a reactor. The capsule is projected into a separation apparatus where it breaks by impact. Its content is then sucked through a thin reactive layer that takes up the desired product. The whole sequence of irradiation, transportation, chemical separation, and counting is controlled by automatic timers. The adaption of this techniq…
The identification and confirmation of isomeric states in 254Rf and 255Rf through conversion electron detection
2020
Abstract The neutron-deficient isotopes 254,255Rf were produced in the fusion-evaporation reaction 50Ti + 206Pb at the gas-filled recoil separator TASCA. Decay properties of these nuclei were investigated by applying fast digital electronics. A search for isomeric states in both isotopes was performed by using the accompanying conversion electron emissions. Isomeric states with half-lives of 4(1) μs and >30 μs were measured for 254Rf and 255Rf, respectively, which confirm the findings at different separators. The present experimental results demonstrate the great potential of fast digital electronics for measurements of isomeric states in the heaviest nuclei, which are only producible in sm…