Observation of spin-aligned secondary fragment beams ofB14

Spin-alignment and g-factor measurement of the $I^{\pi}$ = 12+ isomer in 192Pb produced in the relativistic-energy fragmentation of a 238U beam

“…The spin-alignment of ions produced in fragmentation reactions is correlated with the momentum of the products [5]. Nuclei with lower (or higher) momentum than the mean of the momentum distribution correspond to fragments to which the linear momentum has been transferred either parallel or antiparallel to the beam direction.…”

“…The mechanism by which the nuclear spinalignment or polarization is produced in such processes is only partly understood [5,6,8,9]. The spin orientation of nuclei produced in the reaction can be reduced or even lost due to the hyperfine interaction with its randomly oriented electron spin during the flight path through the mass separator.…”

“…The spin orientation of nuclei produced in the reaction can be reduced or even lost due to the hyperfine interaction with its randomly oriented electron spin during the flight path through the mass separator. By producing fully stripped nuclei and maintaining them fully stripped all the time when passing through the analyzing system -with magnets, particle detectors and absorbers-the nuclear spin orientation can be preserved [1,2,5,6].…”

“…Fragmentation reactions have been employed rather in few experiments for investigations of electromagnetic moments in isomeric states in light and medium mass nuclei [1,2,[5][6][7]. The mechanism by which the nuclear spinalignment or polarization is produced in such processes is only partly understood [5,6,8,9].…”

Spin alignment of excited projectiles due to target spin-flip interactions

“…Spin alignment is found in a diverse number of reactions including inelastic scattering [1][2][3][4][5][6], deep elastic scatter ing [7][8][9][10], projectile fragmentation [11][12][13][14][15][16][17][18], fission [19,20], Coulomb excitation [21], and other direct reactions [22][23][24][25][26][27][28], For peripheral reactions, the dominant angular momentum in the reaction is the initial orbital angular momentum between the projectile and target, which is perpendicular to both the beam axis and the reaction plane. It is therefore not surprising that many fragments have their spin aligned, on av erage, parallel to this direction [7,11,12,[21][22][23]27], However, there are some cases where different alignments are found [13][14][15][16]18], Measurement of a fragment's spin alignment can be deduced from its decay products, including fi particles though NMR techniques [11,12], from the recoil induced by y-ray decay [23,2...…”