Wei-fan Yang

A new isotope of protactinium:239Pa

A new nuclide239Pa was produced by 50MeV/u18O bombardment of uranium. A radiochemical separation method was employed for preparing sources of239Pa. The protactinium isotope239Pa has been identified for the first time by the results observed from the decay of the239Pa and its daughter239U. The half-life of239Pa has been determined to be 106 ±30min.

Identification of 186mTa

186m Ta and 186 Ta have been produced by irradiation of nat W with 14 MeV neutrons. The unreported tantalum isomer 186m Ta has been identified by means of measuring known γ rays from 186 Ta β-decay...

Solvent Extraction Study of 233Pa(V) with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone

Various techniques have been developed for extraction and separation of protactinium (Pa), of which solvent extraction is considered to be the simplest method and also rapid, selective and efficient.(1,2)) The extraction pattern of Pa is relevant with respect to the chemistry of dubnium (Db), as Db resembles its pseudo homologue protactinium rather than its closest homologue tantalum (Ta). Kratz et al, (3)) Paulus et al.(4)) and Zimmermann et al.(5)) studied the extraction behavior of Pa-233 and its other homologues with triisooctyl amine (TIOA), tri-n-octyl amine (TOA) and aliquat 336, a quaternary ammonium salt. The TIOA-HCl-HF and Aliquat 336-HCl-HF systems were found to be suitable for extraction pattern studies of Db as well as its homologue and pseudo-homologue, Nb and Pa, respectively. Therefore, studying the extraction pattern of Pa with different types of extracting agents is important to identify similarities with the extraction pattern of Db and thereby unravel some of the chemistry of Db. Recently, 1-phenyl-3-methyl-4-benzoyl-5-pyrazoloiie (PMBP) has drawn attention from analytical chemists for its capability to extract heavy metals.(6,7)) The PMBP-mineral acid system does not form a third phase in contrast to high molecular weight-mineral acid systems(8,9)) and the separation time between organic and aqueous phases is almost instantaneous. Keeping in mind the above facts, we report the solvent extraction behavior of Pa with PMBP diluted in xylene or chloroform from HCl, HCl-HF, HNO3 and H2SO4 media.

Observation of 186mTa

Abstract Unreported tantalum isomer 186m Ta has been produced through the reaction 186 W(n,p) by irradiation of nat W with 14 MeV neutrons. The activity of 186m Ta and 186 Ta was measured using HPGe detectors and several X-γ as well as γ-γ coincidence arrangements. The 186m Ta has been identified by means of measuring known γ rays from 186 Ta β-decay. The half-life of 186m Ta has been determined to be (1.5±0.1) min.

Production and identification of new neutron-deficient isotope235Am in region of transuranium

A new transuranium neutron-deficient isotope235Am was produced by 35 MeV proton to bombard the rare radioactive238Pu target. The products were transported and collected by the He-jet system. The Am isotopes were separated and purified by radiochemistry method and the y-ray, X-ray and y-X(y) coincidence of the samples was measured. The synthesis of235Am was definitely identified. Its measured half-life is (15±5) min.