Master Thesis experiment
Measurement of total reaction cross section for 6He ions on a 12C target at energy 169 MeV

Values of reaction cross sections give us information about interaction between nuclei - intreraction potential between particle and target. Knowledge about such potential is necessary for astrophysical calculations, for example nucleosynthesis in stars. Other application is transmutation process - method to remove long-lived nuclear waste with high energy protons. If we investigate interaction with nuclear fuel, we can increase efficiency of this process. Experiment was make in Flerov Laboratory of Nuclear Reactions (JINR, Dubna) on separator ACCULINNA and it was measurement of total reaction cross section for 6He ions on a 12C target at energy 169 MeV.

The separator ACCULINNA is installed at a primary beam line of cyclotron U-400M. The achromatic ion-optical system is optimized for focusing fragments emerging from the production target, placed in the object plane F1, to the achromatic focal plane F3. 11B ions hitting a 350-mg/cm2 stationary beryllium target. The desired secondary beams are separated according their magnetic rigidity with the aid of magnets D1 and D2 and formed by magnetic quadrupole lenses Q1 - Q15. A wedge-shaped degrader installed in the intermediate dispersive focal plane F2 helps to remove background from the selected beam.
More details are on JINR Page http://flerovlab.jinr.ru/flnr/

The target is placed plane F4 located beyond the 2-meter concrete wall of the U-400M hall - possibility to work with neutron detectors in the proximity of the reaction chamber. The secondary beams of 6He and 8He nuclei with energies of about 25 AMeV allowed to gain new insights into the structure of neutron halo nuclei through the study of one- and two- neutron transfer reactions. Such beams offer favorable conditions for the production of so far unknown particle-unstable nuclei beyond the neutron drip line [1].