Energy spectra of nuclear fragments produced by high energy protons

Abstract

Fragment energy spectra from the 2.1-and 4.9-GeV proton irradiation of C, Al, Ag, and U targets were measured at several angles to the beam for products ranging from He up to Ar for the heavier targets. The fragments were detected in a telescope consisting of a gas AE counter and a silicon E counter. The carbon target measurements are compared with previous data from projectile fragmentation studies. A Maxwellian type functional form which fits the energy spectra from all the targets is presented. The spectra were integrated to obtain values of the cross section as a function of atomic number.

Liquid-Gas Phase Transition in Nuclear Multifragmentation

“…Multifragmentation was seen in high-energy proton-nucleus collisions [15][16][17][18] before systematic studies were undertaken in nucleus-nucleus collisions. For a proton incident on a nucleus the picture is as follows.…”

“…Most early multifragmentation experiments are inclusive measurements [15][16][17][18][19][20], i.e. particles are identified with no requirements that other particles from the same event should be detected in coincidence.…”

“…Long before intermediate energy collisions which are best described by multifragmenation mechanisms, the concept of temperature was being used routinely to describe heavy ion collisions at Bevalac (see for example [16]). In cascade [55] or transport calculations [56] one can follow in microscopic models how the original ordered motion of the beam gets dispersed into a Maxwell-Boltzmann distribution through two-body collisions.…”

“…In a set of three papers [157][158][159] Pandharipande and coworkers studied disassembly of hot classical drops as well as collisions between cold charged argon balls containing A 1 and A 2 particles. The chosen values of (A 1 , A 2 ) were (108,108), (200,16) and (65,65) [157]. The interaction between atoms was a truncated (12,6) potential and a Coulomb interaction was added.…”

The possibility of time resonance (explosion) phenomena in high-energy nuclear reactions

“…For lighter projectiles (from p to 20 Ne) with energies above 1 -10 Gev/nucl, studies have observed structureless, exponentially decaying inclusive and non-inclusive energy spectra, often accompanied by slight oscillations over the range of projectiles and projectile energies, targets, and registered final fragments (see, for example, [1][2][3][4][5][6][7][8]). For heavier projectiles these phenomena were observed even for smaller energies (see, for instance, [9]).…”