Target-thickness-dependent electron emission from carbon foils bombarded with swift highly charged heavy ions

Journal Article · Sat Apr 01 00:00:00 EST 1995 · Physical Review A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.51.3066· OSTI ID:6544332

Rothard, H; Caraby, C; Cassimi, A; Gervais, B; Grandin, J; Jardin, P; Jung, M ^[1]; Billebaud, A; Chevallier, M ^[2]; Groeneveld, K; Maier, R ^[3]

---

1. Centre Interdisciplinaire de Recherches avec les Ions Lourds, Laboratoire Mixte CEA-CNRS, CIRIL Boite Postale 5133, Rue Claude Bloch, F-14040 Caen Cedex (France)
2. Institut de Physique Nucleaire de Lyon, IN2P3-CNRS/Universite Claude Bernard (Lyon I), 43 Boulevard du 11 Novembre 1918, F-69622 Villeurbanne Cedex (France)
3. Institut fuer Kernphysik der J. W. Goethe Universitaet, August-Euler-Strasse 6, D-60486 Frankfurt am Main (Germany)

We have measured electron yields from the beam entrance and exit surfaces of thin carbon foils ([ital d][approx]4--700 [mu]g/cm[sup 2]) bombarded with swift (13.6 MeV/u) highly charged ([ital q]=16--18) argon ions. The dependence of the electron yields on target thickness and charge state of the ions is analyzed within the framework of an extended semiempirical model. Due to the high velocity of the ions, it is possible to distinguish electron production in primary ionization (related to the stopping power and the effective charge of the ions) from secondary electron production due to the transport of so-called [delta] electrons (cascade multiplication). By combining the experimental results with numerical simulations of electron transport in matter by a Monte Carlo method, we have obtained electron transport lengths of high energy ([ital E][much gt]100 eV) [delta] electrons parallel and perpendicular to the ion trajectory, as well as diffusion lengths of slow electrons ([ital E][much lt]100 eV). In order to study the velocity dependence of these transport lengths, we have not only investigated 13.6 MeV/u Ar ions, but also 1 MeV/u C and 3.9 MeV/u S, for which experimental results are available [Koschar [ital et] [ital al]., Phys. Rev. A 40, 3632 (1989)]. We discuss the origin of electron yield reductions (compared to a simple scaling with the square of the nuclear charge) with heavy ions and present measurements of double differential energy and angular electron distributions of 13.6 MeV/u Ar[sup 17+] ions.

• OSTI ID: 6544332
• Journal Information: Physical Review A; (United States), Vol. 50:4; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CARBON
ION COLLISIONS
ARGON IONS
CORRELATIONS
ELECTRON EMISSION
FOILS
MATHEMATICAL MODELS
MULTICHARGED IONS
THICKNESS
YIELDS
CHARGED PARTICLES
COLLISIONS
DIMENSIONS
ELEMENTS
EMISSION
IONS
NONMETALS
665300* - Interactions Between Beams & Condensed Matter- (1992-)