Ch. Stoller

Evidence for primordial superheavy elements

X-ray analysis of monazite inclusions in micas from Madagascar surrounded by halos of abnormal size revealed several weak lines in the 22-28 keV region interpreted by Gentry et al. (1976) as Lalpha 1 lines of four superheavy elements. The observed structure in the spectra can, however, be explained as caused by K X-ray lines of the trace elements Rb, Sb and Te which are present in monazites and cheralites.

Evidence for a molecular REC-effect in heavy ion collisions

Anisotropy spectra of the MOK X-ray transitions have been measured in F-Al, Al-Al and Cl-Al collisions as a function of the projectile energy. The measurements at higher energies indicate a new molecular effect due to transitions from quasicontinuum states to the MO 1sσ-orbitals.

MO X-ray angular distributions from 1 GeV208Pb+208Pb and209Bi+209Bi collisions

The Doppler shift and the anisotropy of the MO X-rays above the separated-atomK-lines have been measured in208Pb+208Pb and209Bi+209Bi collisions at beam energies between 4.2 and 4.8 MeV/u. The Doppler shift is found to be consistent with a source moving with 90% of the center of mass velocity of the colliding system. One peak is observed in the anisotropy spectrum. This peak might be attributed to transitions from the continuum into the minimum of the 2p1/2σ MO or from the 3p1/2σ and 2p3/2σ MOs into the 2sσ MO near the united atom limit. Radiative electron capture and secondary electron bremsstrahlung could be excluded as major sources of the observed radiation. Contrary to lighter systems no anisotropy corresponding to transitions into the 1sσ orbital could be observed.

The Z-dependence of the MO K X-ray anisotropy peaks

The photon-energy-dependent anisotropies of molecular K X-ray spectra have been investigated for systems with a combined atomic number Zu=Z1+Z2 between 26 (Al-Al) and 94 (Ag-Ag) at beam energies between 3 and 64 MeV. The X-ray energy Ed at the inflection point of the positive slope in the observed anisotropy peak is proportional to the united-atom Kalpha transition energy EKu. The measured ratio between these two energies is fd=1.08+or-0.03. This result is valid for symmetric (Z1=Z2) as well as for asymmetric systems (Z1 not=Z2).