Stopping power of carbon for 9.6-MeV/amuH2+ions

Abstract

Mean energy losses of foil-transmitted Hz+ ions are measured for the incidence of 9.6-MeV/amu H&+ ions on carbon foils of 1.5-8.5 pg/cm thickness. The measured ions are those that have traversed the carbon foil without loss of their original electrons. The stopping power of carbon for 9.6-MeV/amu H2+ ions, derived from the energy losses, is 55.8+4.6 eV/(pg/cm ). The obtained stopping power is compared with that calculated with the first Born approximation. The calculated result is slightly larger than the experimental one.PACS number(s): 34.50. Bw, 34.70.+e, 79.20.Nc, 35.20.i

Simulation of the energy spectra of original versus recombinedH2+molecular ions transmitted through thin foils

“…2(a) and 2(b) we have depicted the electronic stopping and straggling, respectively, obtained here for the original transmitted H 2 + molecular ion and for twice the corresponding values for a single proton. The calculations for the original transmitted H 2 + agree with experiments [15] only at high energy, but clearly differ from the available experimental data for the low- [16][17][18] and intermediate- [19] energy regions. A computer simulation, described in what follows, will help us to understand the behavior of the energy loss of the transmitted H 2 + in the whole range of incident energies.…”

“…One experimental result is depicted for high velocity (v = 19.6 a.u. [15]), i.e., small dwell times, which corresponds to the case of original transmitted molecules.…”

“…The time moving nondissociated is drawn from the lifetime of the H 2 + molecular ion in carbon, 0.23 fs [15]; during the motion of the molecular ion as a whole its interactions with the target are different from those that take place when the molecule is dissociated. Nondissociated molecular ions are supposed to experience the same interactions as an atomic projectile [3], suffering (i) the electronic stopping force and (ii) collisions with the target nuclei.…”

Radiation-Stimulated Conductivity of Some Alkali Halides Induced by 50 ps Electron Pulse Irradiation

“…The crystalline specimens contained uncontrolled impurities with a concentration less than 10 16 cm ± ±3 . The sample dimensions were as large as 10 Â 10 Â 3 mm 3 . A cylindrical hole of 2.5 mm in diameter was drilled in the sample to achieve 60 mm in thickness which was less than the path length of electrons in crystals.…”

Influence of electron capture and loss in the energy distribution of protons dissociated from fast H2+ molecules in carbon foils

“…After an average time of 0.23 fs [11] the H þ 2 molecular ion dissociates into two fragments that travel in a correlated motion, suffering the following interactions: (i) self-retarding force, (ii) wake force due to the electronic excitations induced in the target by the partner fragment, (iii) Coulomb repulsion with its partner (only when both fragments are charged), and (iv) elastic scattering with the target nuclei. Outside the material the exiting fragments only feel the Coulomb repulsion when both emerge as protons.…”