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- Author or Editor: Yang Weifan x
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Abstract
Formation cross sections of near-target products from the reaction of 47MeV/A12C with209Bi targets have been measured. Their independent yields were obtained from their cumulative and partially cumulative yields according to the experimental data measured in this work and correction for mother-daughter decay. From the yield distribution curves of Pt, Au and Hg isotopes constructed it was found that for their peak positions at mass numbers A=188.1, 190.9 and 195.8, the widths of charge distributions are 
= 3.08, 2.80 and 3.74, respectively. The formation cross sections for some near-target neutron-rich new isotopes were extrapolated from the isotopic yield distribution curves.
Abstract
Cross sections of the iodine isotopes formed by the interaction of 47 MeV/u12C ions with133Cs have been measured radiochemically. The iodine isotopic yield distribution was derived from the data and found to be of Gaussian shape. The Gaussian curve has a peak in the vicinity of124I and has a FWHM of 5.5 mass units. The mass loss of the most probable product, 
Ao=At–Ap, is 9.2 mass units. The activities of132I isotope from multinucleon transfer (–2p+1n) reaction were not observed.
Abstract
Protactinium was produced by the reaction of 60 MeV/nucleon 18O with natural uranium. A simple, relatively fast radiochemical procedure was developed, which can be used for the extraction separation of protactinium from uranium and from the complex reaction products using 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone and tri-iso-octylamine as extractants. Measurements of the gamma-ray spectra for the separated protactinium fractions were performed with a HPGe detector. The measured g-ray spectrum of protactinium shows that the decontamination from the main impurity elements, especially zirconium and niobium, is quite satisfactory.
Abstract
Liquid liquid extraction of 46Sc was studied with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP). It has been found that PMBP extracts almost quantitatively scandium from 10-3 to 10-2M HCl solutions. Tributyl phosphate (TBP) has a pronounced antagonistic effect on the extraction process.
Abstract
A rapid radiochemical separation procedure has been finished by using of radiochemical separation and 
-spectrum measurement methods. In this isolation procedure, tantalum nuclides produced by the irradiation of natural tungsten targets with 14 MeV neutrons were extracted by methyl isobutyl ketone (MIBK) in the system of HF-HNO3 mixed solutions. It has been found that tantalum was rapidly and efficiently separated in the isolation procedure and the decontamination factors of tungsten were more than 104. The procedure is simultaneously used to separate tantalum from tungsten bombarded with intermediate energy (47 MeV/u)18O beams. The measured -spectra showed that tantalum can be separated from most elements produced in the nuclear reactions except for a few elements.
Abstract
Barium isotopes were produced by 60 MeV/u 18O ion bombardment of natural uranium via 238U (18O, X) reactions. Ba sources were prepared by radiochemical separation, and measured by a HPGe detector. The cumulative cross sections were obtained by analysis of measured time sequence g-ray spectra. A double peak phenomenon in Ba isotope distribution was observed.
Abstract
The solvent extraction behavior of thorium traces from the hydrochloric acid media with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) is described using 234Th as a tracer. The influence of certain variables such as extractant concentration, acidity, equilibrium time as well as UO2 2+ ions on the extraction of thorium has been investigated systematically. The back-extraction behavior of thorium from the organic phase has also been tested. The results reveal that the percent extraction of 234Th decreases with increasing hydrochloric acid concentration and thorium is easily back-extracted with an 4-6 mol/l aqueous HCl solution. At the same time, the effect of thorium extraction with PMBP was tested employing radioisotopes as multi-tracers in the irradiation of natural uranium with 14-15 MeV neutrons. The results show that thorium can be completely separated from a large amount of uranium and most of the other main reaction products.
Abstract
A new heavy neutron-rich thorium isotope was produced via a multinucleon transfer reaction by irradiation of natural uranium targets with 60 MeV/u18O ions. The Th activities was radiochemically separated from the uranium and mixture of reaction products by the rapid solvent extraction method. Measurements of the gamma-ray spectra were performed with HPGe detectors. The new neutron-rich isotope238Th was identified for the first time based on the observation of the growth and decay of the gamma-ray with energy of 1060.5 keV from the decay of238Pa. The half-life of238Th has been determined to be 9.4±2.0 minutes. Further, a gamma-ray of 89.0 keV with the 8.9-minute half-life was found, which may be due to the decay of the new isotope238Th.
Abstract
A neutron deficient isotope235Am has been produced via the reaction238Pu(p,4n)235Am by 35MeV proton bombardment of238Pu. The reaction products were transported by the He-jet-recoil-transport apparatus. Radiochemical separations were performed by liquid-liquid extraction to isolate the americium fraction from the mixture of the reaction products. The chemically separated Am fractions were used for the X- and gamma-ray measurements. A new neutron-deficient isotope235Am was definitely identified from the growth and decay of its daughter, 25.3·min235Pu and X-γ coincidence measurements. The235Am half-life was determined to be 15±5 min.
