Cross sections for K-shell ionization, x-ray production, or auger-electron production by ion impact

Ion induced electron ejection from solids

Measurements of low energy electron spectra and the total electron yield γ from energetic E/M > 20 keV/U ion/solid-interaction are used to obtain information on electron production and emission processes. The data for monoatomic projectile ions can be explained in the framework of current theories. Comparing the isotachic yields γ of atomic and molecular projectile ions a strong molecular effect on the total electron emission is found. It is explained by an interference on the wake potentials induced in the solid by the two Coulomb-exploding nuclear fragments. From these data the wake wavelength or the plasma frequency of the electron in the solid can be calculated.

Heavy Ion Induced Electron Emission from Solid Surfaces

A phase space compression technique applicable to short-lived particles is proposed. Its specific feature is that it treats each single particle separately by measuring its phase via position sensitive particle detectors and steers it via pulsed electromagnetic deflection. By applying the method to muons, very high quality low energy beams can be obtained. A specific design is presented that should allow to achieve a 50 keV muon beam with 0.1π mm mrad transverse emittance and 104 s−1 intensity. These muons can be further decelerated to ultralow energies so that for example a 50 eV beam with 3π mm mrad and Δp/p = 10−3 is obtained. The overall phase space compression compared to the entrance beam exceeds 1015. With such beams, stopping of muons in atomic beams or on the first atomic layer of a solid can be envisioned. A short list of possible physics applications is given.

Phase space compression of muon beams

We report experimental work on secondary electron emission from both entrance (γb) and exit (γf) surfaces of thin carbon foils traversed by H+, H0 and H+2 projectiles (1.2 MeV/u). Secondary electron coefficients γb and γf, were measured simultaneously. The results are discussed in the framework of a semiempirical model for kinetic emission of target electrons from solid surfaces.

Secondary electron yields from the entrance and exit surfaces of thin carbon foils induced by penetration of H+, H0 and H+2 projectiles (1.2 MeV/u)☆

Deexcitation of projectile inner shell vacancies created while traversing a solid foil may take place via competing processes: a) vacancy sharing with foil atoms in close impacts, b) radiative and non-radiative electron capture, and c) such X-ray and Auger electron transitions as are possible in the heavy ion projectile. The change inK-vacancy creation with foil thickness can be investigated by measuring either projectile or target X-rays where the vacancies are created by Coulomb excitation and processa. In the system Ne (10 MeV) on Al, detecting AlK X-rays, the NeK-vacancy production probability has been determined.

K.D. Sevier

Papers

TotalK-vacancy production in Ne (10 MeV) traversing Al

Electron ejection from beam-tilted-foil experiments

Non-characteristic X-ray emission in NeAl collisions