High Temperature Targets-Ions Source
Development of High Temperature Uranium Carbide Target-Ion Source Units for Production of Isotopes Far from Stability
Tech Area / Field
- PHY-ANU/Atomic and Nuclear Physics/Physics
- FIR-ISO/Isotopes/Fission Reactors
8 Project completed
Senior Project Manager
Bunyatov K S
Nuclear Physics Institute, Russia, Leningrad reg., Gatchina
- Khlopin Radium Institute, Russia, St Petersburg
- Grand Accélérateur National d'Ions Lourds, France, Caen\nIstituto Nazionale di Fisica Nucleare (INFN) / Laboratori Nazionali di Legnaro, Italy, Padova\nSimon Fraser University, Canada, Burnaby
Project summaryThe main goal of the project is the development of a high temperature uranium carbide target – ion source units for effective production of mass-separated radioactive ion beams of different nuclei. The tests of the developed units will be carried out making use of the IRIS (Investigation of Radioactive Ions on Synchrocyclotron) installation on the beam of the PNPI (Petersburg Nuclear Physics Institute) synchrocyclotron.
The developed target – ion source units will allow to produce a wide range of neutron rich and neutron deficient radioactive isotopes in the mass region from Li to Fr. That targets can be used for the secondary accelerated radioactive ion beam production at the ISOL (Isotope Separator On –Line) facilities of the next generation, such as TRIUMF in Canada, projects SPES in LNL, Italy, SPIRAL at GANIL, France, EUROISOL and RIA in USA. To carry out the ISTC project work the Russian scientists and engineers who took part in the activities connected with nuclear weapon will be involved.
The experimental part of the project is as follows:
1. To design and manufacture a prototype of the target unit from a high density uranium carbide with the target material mass of a few hundred grams.
2. To build two new front ends for housing of the tested target-ion source assemblies.
3. To measure the ionization efficiency of Ni, Kr, Rb, Pd, Ag, Cd, In, Sn, Xe, Cs at the off-line test bench with the precision of (20–30)% when the ion source is connected to the oven and to the prototype target unit for pointed out element evaporation.
4. To carry out off-line heating tests (about two weeks) of the prototype target unit (mass of some hundred grams) at a temperature of 2200 °C
5. To measure on-line the yields and delay times of radioactive isotopes of Ni, Kr, Rb, Pd, Ag, Cd, In, Sn, Xe, Cs, and Fr before and after prolonged, about one - three month, heating of the target prototype unit at a temperature up to 2200 °C. The goal is to study three month target operation at a temperature higher than 2000 °C.
6. To design, build and test off-line a target prototype of a high density uranium carbide of the mass 1.5 kg during prolonged one – three month heating.
7. To develop and build a target – ion source unit with NbC, GdC and TaC target materials.
8. To measure on-line the yields and delay time of radioactive isotopes of Rb and Cs from a high temperature NbC, GdC and TaC targets in the temperature interval (2400–3000) °C.
Uranium carbide targets of different density (1.5–11) g/cm3 placed for heating into a tungsten container will be tested in off-line and on-line experiments in the temperature region of (2000–2400) C to find the optimal construction of the target – ion source assembly and to optimize target material structure and density for production of a needed for investigation nuclide. The uranium carbide target of density 11 g/cm3 that was tested for the first time at the IRIS facility demonstrated high yields of produced nuclides and after detailed investigation and optimization of some target – ion source parameters (density, temperature, pressure of CO and the target material) may be a very effective tool for production of neutron rich nuclides far from stability.
Some other metal carbide targets, such as NbC, GdC and TaC will be off-line and on-line investigated to find an optimal compound density for on-line production of extremely neutron deficient isotopes of Rb and Cs.
The experimental part of the project, including measurements of the yields and delay times of on-line produced radioactive isotopes, will be carried out at the IRIS facility.
The computational part of the project concerns the prediction of the expected yields of produced nuclides, making use of existing codes and taking into account the target material mass, proton beam intensity and measured delay times for radioactive atoms of different elements.
The scientific-technical significance of the project relates to the fact that nearly all nuclear physics information at present time is obtained by experiments at ISOL facilities installed on the beams of different bombarding particles - protons, thermal neutrons and heavy ions by investigations of short lived radioactive nuclei. The use of a high energy (0.5–2) GeV bombarding proton beam with a current of some milliamperes gives the possibility of producing the widest range of proton and neutron rich radioactive nuclei. Protons, bombarding thick (some hundred grams) targets provide very high yields of radioactive isotopes by spallation, fission and fragmentation reactions. As it was demonstrated by the latest on-line experiments, the use of two step production reaction by generating secondary neutrons, when proton or deutron beams hit a tantalum or tungsten rod placed close by uranium carbide target, gives the enhancement of magnitude of the yields of neutron rich isotopes more than order of magnitude.
The production of intensive accelerated radioactive nuclear beams (RNB) is also of great importance for astrophysics when the ideas about the creation of chemical elements in the Universe and the evolution of stars are tested experimentally by the interaction of RNB with a hydrogen target. Radioactive ion beams also are widely exploited for solid state physic purposes where radioactive ion implantation is used to investigate the properties of materials, particularly semiconductors. Radioactive nuclear beams are used for modern medicine as well, providing a fast and harmless way of cancer diagnostic.
Besides scientists from Russia, the scientists from Laboratori Nazionale di Legnaro, INFN, Italy and Laboratory GANIL, France will be involved in the project. They will participate in the experiments which will be carried out according the project program at the IRIS facility and will make the calculations of the yields of isotopes which are planned to produce, making use of existing codes and taking into account the measured delay times. It also suggested that Italian and French scientists will do calculations modeling the effect of the diffusion and effusion mechanism on the release process from the target material and from the internal volume of the target. They will participate, as well, in seminars and workshops during the course of the project.
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