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Abstract  

The cross-sections for production of alpha-activities via spallation in the interaction of thorium with 600 MeV protons from the CERN Synchrocyclotron (ISOLDE beam) have been measured, employing on-line techniques. Products with half-lives in the range 4 sec<T<1 month were determined. During the course of this investigation the existence of a 62 sec isomer of222Ac was confirmed.

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Abstract  

The gas transport system (GTS) brings short-lived radioactive nuclides to low back-ground areas for chemical separation and/or on-line α-, γ- and X-ray analysis. A pressure difference of a few Torr (3–5) is enough to maintain the transport, thus eliminating the need for costly pumping systems and making it possible to perform chemistry at atmospheric pressure. This technique was applied to a variety of radioactive sources. There is some Z-dependence on the transportation efficiency for the various transported nuclides as a function of the transporting gas and extracting solvent.

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Abstract  

The technique of the investigation of nuclear reactions induced by very heavy ions using solid state detectors is described.

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Abstract  

A gas jet system has been developed at the Darmstadt UNILAC for the investigation of products from damped reactions in U targets induced by U, Pb, or Xe. The design of that system accounts especially for the considerable energy loss of very heavy ions in matter and for the extended spatial distributions of damped reaction products stopped in the gas. Production cross sections for -active nuclides have been measured in the reaction U+U with an aerosol-loaded argon jet.

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Abstract  

We have determined yields of Bi, Po, At and Rn nuclides produced in the interaction of 86 MeV/A12C-ions with lead and bismuth. The yields were determined by off-line measurements of α- and γ-activities in the bombarded foils without chemical separation. Yields of +1 Z-transfer products, are as high as ∼40 mb at maximum, peaking at a mass 4–5 A-units lower than the target mass. Yields of products with up to four protons transferred have been observed.

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Abstract  

Oxamniquine (OXA) is a schistosomicide agent that causes some adverse effects in central nervous system. Intending to improve OXA therapeutic properties, a polymeric prodrug was designed. Currently, there is an increasing interest of thermal analytical techniques in the pharmaceutical area, so differential thermal analysis (DTA) and thermogravimetry (TG) were carried out to evaluate the thermal behavior of OXA, polymethacrylic acid (PMA), [poly(methacrylic-co-oxamniquine methacrylate)acid] (PMOXA) and physical mixture (OXA+PMA). The thermoanalytical profile of the physical mixture showed characteristic events of the thermal decomposition of OXA and PMA. Distinctly, PMOXA DTA curve did not show an endothermic peak at 148.5C indicating that the drug was incorporated into the polymeric system. These results were corroborated by the IR spectroscopy and X-ray diffraction data.

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Abstract  

The search for superheavy elements /SHE/ in the carbonaceous chondrite Allende was continued. This time we carried out a thermochromatographic separation at 1050 °C in O2-, resp., H2-gas flow. The volatile fraction /mostly Pb/ was collected on a Pt-foil or trapped in KOH-solution. The heavy element probes were investigated for spontaneous fission activities. We observed zero spontaneous fission decays during 421 days. This yielded an upper limit of 2.9 fission x kg–1 x year–1 /95% confidence limit/. We were unable to confirm the existence of a spontaneous fission activity in the meteorite Allende.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
R. Esterlund
,
D. Molzahn
,
R. Brandt
,
P. Patzelt
,
P. Vater
,
A. Boos
,
M. Chandratillake
,
I. Grant
,
J. Hemingway
, and
G. Newton

Abstract  

According to calculations of NIX and others, the formation of superheavy elements might occur in heavy-ion reaction systems such as the one under investigation in the present work i.e.,238U+63,65Cu at 9.6 MeV/nucleon. Since previous experiments have indicated that upper limits to the production cross-section for superheavy elements are extremely low, we have carried out two rather long irradiations of 27 hrs and 42 hrs, respectively, at the University of Manchester LINAC. The first run has already been reported on in the literature. In the case of the second run, after chemical separation into HgS, CdS, and La(OH)3 fractions, the samples were assayed simultaneously and continuously over a period of 6 months for alpha-and spontaneous-fission activity, using Si surface-barrier detector. Each sample was at the same time mounted on mice, for the purpose of scanning for fission tracks at a later date. No indications from the data have so far been found that superheavy elements were produced.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
M. Krivopustov
,
J. Adam
,
V. Bradnova
,
R. Brandt
,
V. Butsev
,
P. Golubev
,
V. Kalinnikov
,
J. Karachuk
,
B. Kulakov
,
E.-J. Langrock
,
G. Modolo
,
M. Ochs
,
R. Odoj
,
A. Premyshev
,
V. Pronskich
,
Th. Schmidt
,
V. Stegailov
,
J. Wan
, and
V. Zupko-Sitnikov

Abstract  

First experiments on the transmutation of long-lived129I and237Np using relativistic protons of 3.7 GeV are described. Relativistic protons generate in extended Pb-targets substancial neutron fluences. These neutrons get moderated in paraffin and are used for transmutation as follows:129I(n,)130I and237Np(n,)238Np . The isotopes130I (T 1/2-12.36 h) and238Np (T 1/2=2.117 d) were identified radiochemically. One can estimate the transmutation cross-section (n,) in the given neutron field as (129I(n,))=(10±2)b and (237Np(n,))=(140±30)b The experiments were carried out in November 1996 at the Synchrophasotron, LHE, Dubna, Russia. The investigation has been performed at the Laboratory of High Energies, JINR, Dubna.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
B. Bisplinghoff
,
V. Bradnova
,
R. Brandt
,
K. Dwivedi
,
V. Butsev
,
E. Friedlander
,
S. Gosh
,
Guo Shi-Lun
,
M. Heck
,
Jin Huimin
,
M. Krivopustov
,
B. Kulakov
,
C. Laue
,
L. Lerman
,
Th. Schmidt
,
A. Sosnin
, and
Wang Yu-Lan

Abstract  

An extended Cu-target was irradiated with 22 and 44 GeV carbon ions for about 11.3 and 14.7 hours, respectively. The upper side of the target was in contact with a paraffin-block for the moderation of secondary neutrons. Small holes in the moderator were filled with either lanthanum salts or uranium oxide. The reaction
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $${}^{139}La(n,\gamma ){}^{140}La\mathop \to \limits^{\beta - }$$ \end{document}
was studied via the decay of140La(40h) using radiochemical methods, as has been published. The reaction
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $${}^{238}U(n,\gamma )^{239} U\mathop \to \limits^{\beta - } {}^{239}Np\mathop \to \limits^{\beta - }$$ \end{document}
was studied via the decay of239Np(2.3 d) as well as the reaction U(n,f) using radiochemical methods. In addition, solid state nuclear track detectors were used for fission studies in gold. The yields for the formation of (n,) products agree essentially with other experiments on extended targets carried out at the Dubna Synchrophasotron (LHE, JINR). To a first approximation, the breeding rate of (n, ) products doubles when the carbon energy increases from 22 to 44 GeV. If, however, results at 44 GeV are compared in detail to those at 22 GeV, we observe an excess of (37±9)% in the experimentally observed239Np-breeding rate over theoretical estimations. Experiments using solid state nuclear track detectors give similar results. We present a conception for the interpretation of this fact: There is the evident connection between anomalies we observe in the yield of secondary particles in relativistic heavy ion interactions above a total energy of approximately 30–35 GeV and increased yield of neutrons in this energy region.
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