Differences in the Production of Noncharacteristic Radiation in Gaseous and Solid Targets

Molecular-orbital X-rays and their anisotropies in heavy-ion collisions in solids and gases

“…The theory of Hartung et al [9] ascribes the anisotropy to the rotation of the radiative transition dipole moment during the collision. Another problem which is not yet sufficiently explored is, whether it is possible to distinguish MO xray spectra made by a one-or two-collision process [10][11][12][13]. In the first case, the vacancy is produced in the same collision in which it decays.…”

Experimental determination of the production mechanism for noncharacteristic radiation in swift heavy-ion collisions

“…In less adiabatic collisions (Vp<Ve), however, bremsstrahlung processes (like secondary electron (SEB), radiative ionization (Ri) or nucleusnucleus brcmsstrahlung (NNB)) have been suggested [6, 71 to become important or even dominant in the production mechanism of the observed NCR continua. Even the question whether the observed NCR is produced by a one-or a two-step process is still unsolved [4,8]. The ambigous interpretations [4,8] * Supported by BMFT are based on the comparison of gaseous and solid target x-ray yields normalized to the characteristic K-lines.…”

“…Even the question whether the observed NCR is produced by a one-or a two-step process is still unsolved [4,8]. The ambigous interpretations [4,8] * Supported by BMFT are based on the comparison of gaseous and solid target x-ray yields normalized to the characteristic K-lines. Different fluorescence yields in gaseous and solid targets, however, make this normalization procedure doubtful as pointed out in [8].…”

“…The ambigous interpretations [4,8] * Supported by BMFT are based on the comparison of gaseous and solid target x-ray yields normalized to the characteristic K-lines. Different fluorescence yields in gaseous and solid targets, however, make this normalization procedure doubtful as pointed out in [8]. Absolute cross section measurements should give more reliable information on the mechanism of the NCR.…”

“…All other processes, particularly bremsstrahlung mechanisms are found to be negligible. For high projectile and photon energies the one-step quasimolecular radiation is dominant in solid targets, whereas the two-step process contributes mainly at low projectile and photon energies.The non-characteristic radiation (NCR) above the K-lines emitted in energetic heavy-ion collisions has been the subject of several investigations [1][2][3][4][5][6][7][8] during the last years. For adiabatic collisions (vp ~ v~, where vp and v~ are the projectile and the K-shell electron velocities, respectively) various experimental results [1][2][3][4] were interpreted in the framework of quasimolecular radiation (MOR).…”