Preparation Of Nuclear Targets Research Articles

Nuclear targets within the project of solving CHAllenges in Nuclear DAta

In the frame of the European Commission funded integrated project CHANDA (solving CHAllenges in Nuclear DAta) the importance of nuclear target preparation for the accurateness and reliability of experimental nuclear data is set in a dedicated work package (WP3). The global aim of WP3 is the development of a network for nuclear target preparation and characterization, enabling to coordinate the target production corresponding to the experimental requirements. Therefore, a set of tasks within the work package needs to be followed. Primarily, an inventory of target related facilities and radioisotope providers was created. In the next step a priority list of target requests was made in agreement with the target user considering the technical specification, the scheduled experiments and the availability of the target laboratories. A set of target requests has been assigned to the Target Preparation laboratory of the European Commission – Joint Research Centre – Directorate G (EC-JRC.G.2) in Geel, Belgium. This contribution gives an overview of the nuclear targets that are produced within the CHANDA project. The equipment and techniques available for the preparation and characterization of uranium, plutonium and neptunium layers with an areal density ranging from 60 to 205 μg cm−2 will be emphasized.

An application of a new type deposition method to nuclear target preparation

We have developed a new deposition method, which is based on the vibrational motion of microparticles in the electrostatic field between parallel electrodes. This method is straight forward and does not require any complicated mechanism. It has been found that this deposition technique is useful for the preparation of foils, in both the backed and unbacked condition. The first test results are reported.

Noble gas sputtering calculations using TRIM

In conjunction with our experimental work on sputtering with a saddle-field ion source, the Monte-Carlo program TRansport of Ions in Matter (TRIM) was applied to calculate the sputter yields for a variety of noble gas sputtering applications. Comparison with experiments are shown. Information extracted from these analyses have proved useful in optimizing the experimental sputtering parameters. Calculated sputter yields obtained utilizing TRIM are presented for noble gas sputtering of a variety of materials common to nuclear target preparation.

The preparation of nuclear targets at IMP

The investigation and development of methods of preparation of nuclear targets which have been used for nuclear physics experiments at IMP since 1975 is described. Targets of more than 40 elements, including natural elements, enriched isotopes, lanthanides and actinides, have been produced. Equipment and procedures have been developed for many preparation methods such as electroplating, focused heavy-ion beam sputtering, centrifugal precipitation, rolling, electron bombardment, and resistance heating. The analysis of target films contaminated by oil vapor and the equipment for preparing thin, metallic self-supporting target foils without oil vapor contamination are also described.

Specific nuclear target preparation and characterization techniques used at CBNM

CBNM's nuclear target preparation activity is conceived as a public service towards neutron physicists not only from CBNM, but also from universities, nuclear centres, industry, etc. Besides classical techniques such as electrospraying, spray painting and electrolysis, high-quality actinide deposits are prepared by vacuum deposition of actinide fluorides. These evaporate at approximately 1000 ° C lower temperatures than oxides do. The possibility of preparing actinide deposits is, however, dependent on the preparation of high-quality actinide fluoride powders without water residue. This technique is used to prepare targets for cross section measurements, for fission fragment studies and also for targets used as fission foils. In this case high-accuracy characterisation is obtained by low-geometry α-counting and isotope dilution mass spectrometry (IDMS). Similar techniques were also used to prepare certified reference deposits of 6LiF and B for absolute neutron flux measurements. Finally, it must be mentioned that many deposit requests are carried out on thin foils. Therefore, important development work was carried out to prepare very thin (< 25 μg cm −2) polyimide foils.

Special techniques of nuclear target preparation

A few examples of our recent activities are reported. Among these are simple and reproducible methods to prepare targets of high vapour pressure elements such as P, Zn and Cd, as well as a procedure for the fabrication of thin, pinhole-free Ti foils to be used as beam entrance and particle exit windows in a gas target.

Recent progress in the preparation of nuclear targets at IAE

The development and study of the preparation of nuclear targets at IAE since 1979 are described. Targets of several elements and enriched isotopes have been made by reduction distillation in vacuum or by electroplating. Furthermore, methods such as rolling, centrifugal precipitation, electrospraying, and focused heavy-ion beam sputtering have been set up. An α-particle thickness gauge and a high sensitive quartz thickness gauge have been installed. Rutherford backscattering has been applied successfully to the determination of the thickness and the impurity content of target layers.

Development of a piezoelectric pulsed drop jet device for the preparation of nuclear targets

A piezoelectric pulsed drop jet device has been developed to produce deposits for nuclear measurements. Details are given concerning the construction and performance of the drop generator, the construction of a positioning mechanism and the developement of a steering system (based on a TRS 80 microcomputer). The complete system can produce rectangular and circular deposits of various dimensions and thicknesses. 235U acetate deposits have been prepared in thicknesses varying from 10 μg/cm 2 to 2 mg/cm 2 and their quality is evaluated.

Preparation of Nuclear Targets, A Comprehensive Bibliography

"Preparation of Nuclear Targets, A Comprehensive Bibliography." Nuclear Technology, 59(3), p. 544

Preparation of Nuclear Targets for Particle Accelerators edited by Jozef Jaklovsky

Preparation of Nuclear Targets for Particle Accelerators edited by Jozef Jaklovsky