๐”– Bobbio Scriptorium
โœฆ   LIBER   โœฆ

Low energy radioactive ion beams in Dubna

โœ Scribed by Yu.Ts. Oganessian; Yu.E. Penionzhkevich


Publisher
Elsevier Science
Year
2002
Tongue
English
Weight
65 KB
Volume
701
Category
Article
ISSN
0375-9474

No coin nor oath required. For personal study only.

โœฆ Synopsis


The Dubna radioactive beam factory (DRIBs) [1] will make use of two possibilities for producing secondary beams of radioactive nuclei. During the first phase of the project (Phase I) the possibility for obtaining radioactive nuclei in fragmentation reactions of stable nuclei, accelerated by the cyclotron U400M to intermediate energies (โˆผ 50 MeV A -1 ), will be realized. The fragmentation products, obtained in a special ion source, will be converted into single-charged ions, which after transportation to the second cyclotron (U400) will be accelerated up to energies of โˆผ 20-25 MeV A -1 . This method will allow obtaining mainly beams of light radioactive nuclei with Z 30 with intensities up to 10 8 pps (e.g., nuclei such as 6 He). In the second phase of the project (Phase II) it is supposed to produce and accelerate radioactive neutron-rich nuclei in the mass region 80 A 140. This mass region corresponds to the fragments of low-energy fission of heavy nuclei. For this reason use will be made of the photofission of 238 U. The ฮณ -quanta will be produced by the electron accelerator (the microtron MT-25), where the electron beam with an intensity of about 20 ยตA has an energy of 25 MeV. With the help of a special converter the electron beam is transformed into a beam of ฮณ -quanta with up to 25 MeV energy and a flux of 10 14 s -1 . This beam, focused into a narrow angle, will fall onto a 238 U-target weighing 100 g. It is wellknown that the photofission cross section has a maximum corresponding to the giant dipole resonance at an energy of the ฮณ -quanta equal to E ฮณ = 13.5-14 MeV [2]. This brings forth an increase of the photofission probability. The yield of the fission fragments will increase as a result of the interactions of the secondary neutrons (ฮณ n and fission neutrons) with the U-target. When the mentioned above parameters of the beam and target are realized, one can get as much as 10 11 fission fragments/second. Taking into account the widths of the mass and charge distributions of the fragments, the yields of definite fission fragments can be estimated. When the efficiency of the ion source and the transport system amounts to some 20-30% it is possible to obtain beams of fission fragments in the region of Kr and Xe with an intensity of up to 10 9 s -1 . Simultaneously with the fragments situated close to the maxima of the mass distribution (A = 90 and 130), asymmetric fission fragments are formed with a rather high yield. For the isotopes situated at the "tails" of the fragment * Corresponding author.


๐Ÿ“œ SIMILAR VOLUMES


Radioactive ion beam research made in Du
โœ G.M. Ter-Akopian; Yu.Ts. Oganessian; M.G. Itkis; G.G. Gulbekian; D.D. Bogdanov; ๐Ÿ“‚ Article ๐Ÿ“… 2004 ๐Ÿ› Elsevier Science ๐ŸŒ English โš– 612 KB

Operational parameters are given for ACCULINNA set-up used in experiments with 20-40 MeV secondary beams of 6He and sHe nuclei. The lay-out of DRIBS and the results of the (jHe beam acceleration made at this new ISOL type facility are presented. The main directions of recent experimental studies mad

Low energy ion beams
๐Ÿ“‚ Article ๐Ÿ“… 1980 ๐Ÿ› Elsevier Science ๐ŸŒ English โš– 176 KB
Low energy ion beams-2
โœ The Meetings Officer The Institute of Physics ๐Ÿ“‚ Article ๐Ÿ“… 1979 ๐Ÿ› Elsevier Science ๐ŸŒ English โš– 124 KB