Induced Radioactivity in Heavy Ions Reactions
Impact of Heavy Ion-Induced Radioactivity and Secondary Neutrons on Biosphere and Environment: Experiments and Long-Term Predictions
Tech Area / Field
- PHY-ANU/Atomic and Nuclear Physics/Physics
3 Approved without Funding
ITEF (ITEP), Russia, Moscow
- Los Alamos National Laboratory, USA, NM, Los-Alamos\nGSI, Germany, Darmstadt\nTokyo Institute of Technology / Research Laboratory for Nuclear Reactors, Japan, Tokyo
Project summaryThe Project is aimed at experimental studying the impact of induced radioactivity and secondary neutrons produced in heavy-ion reactions on the biosphere and environment.
In recent years, requirements from new technological and research applications for particle accelerators have emerged, giving rise to new radiation shielding aspects and problems. For the new high-power accelerators currently being designed, activation of the accelerator structure has become an important issue. The radiation and ecological hazard may arise from the various accelerator operation factors (the immediate effect of the particle beams; the activation of aerosols, specks of dust, and structure elements; the high-energy neutron production, etc.) The main emphasis of new heavy ion accelerator projects (SIS-200, GSI; TWAC, ITEP; MUSES, RIKEN; or future facility for heavy ion inertial fusion) focuses on the technical developments needed to increase the achievable beam intensities by up to two orders of magnitude. The activation, however, produced by accelerators of such high power, has not yet been quantified. Hence, novel safety aspects evolving from the increased radioactive inventory of such facilities will obviously play the major role in the design and approval procedure. The experimental study of potential radiation risks and developments for improved minimization of these risks during normal accelerator operation are proposed in this project.
The present Project Proposal suggests that experimental results should be obtained directly in the experiments using new high power beam facility - the Tera Watt Accumulator (TWAC) at the Institute for Theoretical and Experimental Physics (ITEP) at Moscow. The 12C ions accelerated up to 100-4,000 MeV/A 12C will irradiate thin and thick targets made of accelerator structure elements. The results to be obtained are planned also to use in verifying different codes (CASCADE, LAQGSM, and others), in estimating the potential radiation risks due to secondary neutrons and to alpha-, beta-, and gamma-activity of structure materials, and in making effort to minimize the risks under the nominal accelerator performance and in possible emergencies.
In the thin target experiments, the cross sections for production of radioactive residual nuclei will be determined as dependent on target material and ion energy. Simultaneously, the radiation and dose characteristics of irradiated materials will be determined, and efforts will be made to predict the later behaviour of the characteristics. The comparison of measured data with the high energy codes (CASCADE, LAQGSM etc.) simulations will qualitatively demonstrate a level of reliability (agreement between experiment and calculation) of code simulated reaction product yields for the nuclei-nuclei interactions.
In the thick target experiments, the threshold reaction rates outside and inside the targets will be determined as dependent on target material and on the accelerated particle specie and energy. The comparison among the reaction rates to be measured and simulated will qualitatively demonstrate a level of reliability (agreement between experiment and calculation) of the codes (CASCADE, LAQGSM etc..) simulated spectra of neutrons produced in the nuclei-nuclei interactions.
The joint comparison results for thin and thick targets will permit long-term predictions of the radiation hazard from high-intensity heavy ion facilities.
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