Deuteron production in α-nucleus collisions from 200 to 800 MeV per nucleon

Abstract

Deuteron spectra at laboratory angles from 30 to 90 were measured in a+(Pb, Cu, and C) collisions at 800, 600, and 200 MeV/nucleon, and a+(Pb and C) collisions at 400 MeV/nucleon. The coalescence relation between protons and deuterons was examined for the inclusive part of the spectra. The size of the interacting region was evaluated from the observed coalescence coefficients. The rms radius is typically 4 -5 fm, depending of the target mass. The proton and deuteron energy spectra corresponding to central collisions were fitted assuming emission from a single source moving with a velocity intermediate between that of the projectile and the target. The extracted "temperatures" are independent of the nature of the emitted particle, indicating that the fragments have a common source. The best fits were achieved for 200and 400-MeV/nucleon reactions. Spectra of deuteron-like pairs, including real deuterons and neutron-proton pairs that may be contained in a larger nuclear cluster, are compared to the prediction of an intranuclear cascade model incorporating a clustering algorithm based on a classical coalescence prescription. Best agreements between experimental and predicted deuteron-like spectra occur for 800and 600-MeV/nucleon collisions.

Origin of light nuclei in near earth orbit

“…A few 4 He fragmentation studies have been reported in the literature over the momentum range of interest here [24,25,26]. The production of non velocity-conserving light fragments in p and 4 He induced collisions is also fairly well documented experimentally [13,17,14].…”

“…He, produced at large scattering angles in such collisions, can be described by means of a variety of models which are all variations approximating more or less successfully the complex multiple nucleon-nucleon scattering processes and nuclear collective effects governing these collisions [12,15,16] (see also [13,14,17]). In this context, the coalescence model [18,19] stands as the most successful phenomenological approach of the production cross section for light nuclei, with a remarkable ability to reproducing data over a very wide range of incident energies [14,17,20,21]. In this approach, nucleons coalesce into clusters whenever they fall within the coalescence radius(momentum) in the final state of the collision.…”

“…This latter kinematical domain is associated to smaller impact parameters and larger energy dissipation due to larger density overlaps in the collisions. In this region, the simple fragmentation picture [11] fails and the description of the collision in terms of the various models based on thermodynamics and spectatorparticipant pictures [12,13,14] are more appropriate The energy distributions of very light fragments…”

Intranuclear cascade-percolation approach for protons and light fragments production in neon-niobium reactions at 400 and 800 MeV per nucleon

“…The Table IV. 400 MeV/nucleon Central Peripheral [14][15][16][17][18][19][20][21][22][23][24][25][26][27] [ [5][6][7][8][9][10][11][12][13] 800 MeV/nucleon Central Peripheral [18][19][20][21][22][23][24][25][26][27][28][29][30] [ [5][6][7][8][9][10][11][12][13][14][15][16][17] The rapidity distributions of baryons [21] could be used in order to infer some...…”

Extended Intranuclear Cascade model for pickup reactions induced by 50-MeV-range protons

“…These processes are responsible for reaction of incident energies above 100 MeV, and are suppressed strongly at the lower energies. INC models developed elsewhere [6,7] incorporate the coalescence model, in which emitting particles within a certain phase space can be combined to form a cluster. The coalescence model is similar to the indirect pickup model, and cannot explain the high energy part of spectra where clusters have energies close to the incident beam energy.…”