Measurements of the cross-section of 111Cd(n,n′)111mCd reaction for 241Am/Be neutrons

The cross-section of the [Formula: see text] reaction was measured with [Formula: see text] neutrons using a natural cadmium target [Formula: see text]. The neutron fluence and mean neutron energy of the source were determined using the ISO 8529-1 neutron spectrum and the known cross-sections of the monitor reaction [Formula: see text]. In order to measure the poor [Formula: see text]-ray activity of the reaction products, an HPGe detector with 70% detection efficiency surrounded by an adequate graded shield was applied. The efficiency calculations for the detector were performed using standard point calibration sources and the EFFTRAN efficiency code. Using the measured values of the neutron flux and the induced [Formula: see text]-ray activity of [Formula: see text], the cross-section of the [Formula: see text] reaction at the average neutron energy of 4.05 MeV was found to be [Formula: see text] mb. An estimation of the contribution to the total cross-section by the accompanied reactions [Formula: see text] and [Formula: see text] was achieved and the related cross-sections were found to be 0.16 mb and 8.99 mb, respectively.

Pengaruh Konsentrasi Kadmium Terhadap Perubahan warna Dan Persentase Jenis Kelamin Jantan Anakan Daphnia magna

Cadmium is one of dangerous heavy metal and it can cause water pollution. As an alternative early warning toward heavy metal in water, Daphnia magna can be used as biology indicator water pollution that caused by heavy metal. Daphnia magna is organism that ussualy used for bioassay in many progressing countries, because that organism have important role in freshwater ecology, short life cycle about 3 weeks and sensitive toward chemical environment. Grade of toxicity heavy metal can measured with lethal and sub lethal parameter. In Daphnia magna, sub lethal parameter that can be observe are colour changes and male sex percentage neonates. The purpose of this research was to know the colour changes and male sex percentage neonates Daphnia magna in different concentration of cadmium. Target of this research is to gets information about level colour changes and male sex percentage neonates Daphnia magna in different concentration of cadmium. The main parameter was colour changes and male sex percentage neonates and the secondary parameters were water quality (temperature, pH, dissolved oxygen and NH3) The result of research of giving different cadmium concentration to the adult female Daphnia magna not showing significant influence, nevertheless it is showing significant influence toward male sex percentage neonates Daphnia magna. The treatment with cadmium concentration 0,0004 mg/l produce 100% male neonates Daphnia magna. Water quality during research were in optimal conditions to support Daphnia magna life, those are temperature 26°C, pH range from 8,0 – 8,2 and dissolve oxygen (DO) range from 8,5 – 9,0 mg/l and ammonia 0 – 0,03 mg/l.

Synthesis of CdS Nanoparticles by Laser Ablation of Metallic Cadmium Target in Presence Different Precursors

The special features of nanoparticles formation by laser ablation of volume metallic zinc targets in various solvents using sulfur precursors are studied. Semiconductor cadmium sulphide nanoparticles with average sizes 10–15 nm are synthesized by zinc ablation in the presence of hydrogen sulfide and thioacetamide, and their composition, structure, and optical properties are investigated. It is established that with the use of H2S, only CdS particles are formed in the medium.

Comparison of Elemental Sensitivities Induced by Radioisotope and Secondary Target Excitation for Simultaneous Multielement X-Ray Analysis

SummaryThe major advantage of secondary-target X-ray fluorescence analysis is the enchancement of sensitivity and detection limit of an element or small group of elements with similiar atomic numbers by selecting a target material which produces X-rays slightly higher than the absorption edges of the analysis of interest. Secondary target excitation systems are, however, being employed for simultaneous determinations of a large range of elements. Thus, it was decided to compare the application of a simple secondary target X-ray fluorescence system with excitation from a Cd-109 annular radioisotope source.A simple secondary target X-ray fluorescence system was constructed and optimized which operates at less than 800 kilowatts. The “relative” elemental sensitivities of this system. and a radioisotope system with a Cd-109 annular source were compared by the analysis of the 1-2-3-multi-spectral standard from Chemplex which contains 1.23% of 53 elements. The characteristic X-rays were collected with the same Si(Li) detector and analyzed with the same Apple lie microprocessor with a Nucleus ADC/interface card. Finally, the secondary target system described herein with a molybdenum X-ray tube and zirconium or cadmium target produced similiar elemental sensitivities as a Cd-109 annular source of about 7.5 mCi and 5.0 mCi intensity respectively.