Studies of intermediate-mass fragment emission in theHe3+

Abstract

Intermediate-mass fragments formed in reactions of He ions with ""Ag and ' Au targets have been studied at five energies between 0.48 and 3.6 GeV. Inclusive measurements show that as the bombarding energy increases, there is a strong enhancement in fragment cross sections and a trend toward isotropic angular distributions. Between 0.90 and 1.8 GeV, a change in the emission mechanism is suggested by (1) kinetic energy spectra with high-energy tails that become distinctly flatter"(2) a broadening of the spectral Coulomb peaks toward lower energies, and (3) charge distributions that become constant, exhibiting a power-law exponent~=2.0. Exclusive studies of the He+""Ag system at 0.90 and 3.6 GeV detected multifragment events with multiplicities up to four. The probability for high-multiplicity events increases about 40-fold between 0.90 and 3.6 GeV. At both energies, the kinetic energy spectra depend on multiplicity, especially when triggering on backward-emitted fragments. For multiplicity three events, a rapidity analysis of the data at 3.6 GeV is consistent with a single, relatively low source velocity, V+=0.4 cm/ns. The data are compared with predictions of a coplanarity-sphericity calculation, the sequential statistical decay code GEMINI, and a hybrid intranuclear cascade/percolation model.PACS number(s): 25.55. -e

Energy dissipation and multifragment decay in theHe3+Kwiatkowski1, Friedman2, Woo3 et al. 1994Phys. Rev. CSelf Cite18140View full textAdd to dashboardCite

“…6 we compare the relative multiplicity (M) distribution from the 3.6 GeV data of Ref. [8] [20], which included angular momentum (I "=76h), have also been shown [31] to underpredict the data by nearly 3 orders of magnitude at M = 4. These comparisons demonstrate a strong sensitivity of the multiplicity distributions to the compressibility parameter.…”

Light-ion-induced multifragmentation: The ISiS project

“…Based upon previous inclusive and semi-exclusive studies [17], the ISiS 4π array was designed in a spherical geometry, with very low detector thresholds and a large dynamic range for LCPs [LCP = H and He] and IMFs [21]. Particle identification was based on triple telescopes composed of an ion-implanted silicon detector, preceded by a gas-ion chamber for low energy fragments and followed by a CsI (Tℓ) crystal for the most energetic particles, primarily LCPs.…”

Multifragmentation study on 30 AMeV32S+58Ni

“…Other investigations are based on the sphericity/ coplanarity of the eventwise extracted momentum tensor [41,42]. The most comprehensive results are due to Bauge et al [38] who derive a mean IMF emission time of 400 fm/c for 35 AMeV Kr+Nb, which then goes down to 125 fm/c where it stays constant up to the maximum bombarding energy investigated (75 AMeV).…”

“…The most comprehensive results are due to Bauge et al [38] who derive a mean IMF emission time of 400 fm/c for 35 AMeV Kr+Nb, which then goes down to 125 fm/c where it stays constant up to the maximum bombarding energy investigated (75 AMeV). Some studies lead only to a decision between the opposite scen-arios of "prompt" or "sequential" decay [31,34,42,43], or even state only the compatibility with the one or the other [35,40,44].…”