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[en] A very high efficiency liquid-liquid chromatography (LLC) system based on 5- and 20-μm diameter porous silica microspheres was used to effect radiochemical separations of metal ions that required very large decontamination factors and/or high speeds. The stationary phase was 25-30% (w/w) of di(2-ethylhexyl) orthophosphoric acid (HDEHP) in dodecane. Nitric acid was used as the mobile phase. The mass transfer coefficient term, C, was determined from height equivalent to a theoretical plate vs. interstitial linear velocity data for the elution of Ca²⁺ and compared with values calculated from the interfacial mass transfer coefficients measured in the corresponding liquid-liquid extraction system. The HDEHP high-efficiency LLC system was also investigated for possible use in enriching the naturally occurring isotopes of calcium. Isotopic exchange constants for ⁴⁰Ca or ⁴²Ca and ⁴⁸Ca were measured chromatographically as a function of temperature. The enrichment of calcium isotopes was attempted on coupled columns at low flow velocities

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[en] An active target has been developed for study of the Hoyle like states in ¹⁶O. It is a position and time sensitive detector system based on the low-pressure MWPC technique and Si detectors. The few Torr pressure of methylal ((OCH₃)₂CH₂) serves as a working gas for the MWPC operation, and in addition the oxygen atoms of the methylal molecules serve as an experimental target. The main advantage of this new target-detector system is a high sensitivity to the low-energy, highly ionizing particles, produced after photodisintegration of ¹⁶O, and insensitivity to γ-rays and minimum ionizing particles, thus allowing to detect only the products of the nuclear reaction of interest. The threshold energy for detection of α particles and 2C nuclei are about 50 keV and 100 keV, respectively. Timing and position resolution of lowpressure MWPC modules was investigated using an α-particle source. This paper discusses the architecture of the active target and test results of the prototype MWPC detector. This has been constructed to study cluster states at 15.1 MeV in ¹⁶O using proton beams from the Yerevan proton cyclotron and laser Compton backscattered photon beams at the ELI-NP facility

[en] Highlights: • The analysis of ²³⁹Pu was performed using the SAMMY Code for Neutron Transmission, Capture, and Fission cross-sections in the resolved resonance region up to 2.5 keV. • Due to the difficulties of processing large covariance matrices, the evaluations were performed in the following distinct uncorrelated energy regions: 0.0–1.0 keV, 1.0 keV–2.0 keV, and 2.0 keV–2.5 keV. - Abstract: The analysis of ²³⁹Pu was performed using the SAMMY Code for Neutron Transmission, Capture, and Fission cross-sections in the resolved resonance region up to 2.5 keV. Due to the difficulties of processing large covariance matrices, the evaluations were performed in the following distinct uncorrelated energy regions: 0.0–1.0 keV, 1.0 keV–2.0 keV, and 2.0 keV–2.5 keV. By using version 8.0.0 of the SAMMY code, the treatment of large resonance parameter covariance matrices was improved significantly. The aim of this work is to analyze the experimental data using a self-developed experimental nuclear data fitting code FITWR and analyze it with the SAMMY code, then compare the results with Bayes method. Finally, the output results from these methods is processed by the SAMMY code in order to obtain covariance matrix resonance parameters in the energy range from 0 to 2.5 keV. All the computational experiments done for this paper was carried out at IMAN1 Center – Jordan’s National Supercomputing Center (IMAN1).

[en] Results of mass distributions of fission fragments from the thermal neutrons induced fission of ²³⁹Pu in the high kinetic energy region are analyzed. Our measurements state that the fission configurations corresponding to the sup(106-108)Mo fragments are the less excited. Fragmentations of odd and even masses are equally distributed. Different interpretations of these results are compared

[en] The difficult task of removing large pieces of highly contaminated equipment from an obsolete plutonium-239 facility was completed in a seven-month operation that included structural alteration of the process building. Detailed job planning, job execution and contamination control were major factors in accomplishing the task

[en] Lifetimes of negative muons bound to ²³²Th, ²³⁵U, ²³⁸U and ²³⁹Pu have been determined to be 80.4+-2.0 ns (²³²Th), 78+-4 ns(²³⁵U), 81.5+-2.0 ns(²³⁸U) and 77.5+-2.0 ns(²³⁹Pu) by observing decay electrons from muons. Systematics of total muon capture rates are discussed. They are also compared with the lifetimes determined by fission fragments in view of possible fission-isomer excitation by muons. (Auth.)

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