Changes in surface composition and morphology of UF4 targets during heavy ion irradiation

Elucidation of constant current density molecular plating

“…The method is well-known to have many desirable properties, like a quantitative deposition yield of the produced layers, which usually show acceptable uniformity and good stability to the bombardments with intense particle beams [11]. Despite MP to be widely used, there are, however, rather few attempts reported where a characterization of the layers by standard analytical techniques was performed [12,13], and a detailed elucidation of even some main features of the process is still largely lacking. Work has focused rather on gaining empirical evidence on how to further improve the properties of the produced layers.…”

High quality actinide targets

“…Discoloration of the targets is usually observed with possible loss of actinide material. We conducted a detailed examination of the changes in the surface composition and morphology of 238 UF 4 irradiated with 5 9 10 18 37 Cl ions (at an energy of 195 MeV) [8]. We observed changes in the physical structure of the actinide deposits that indicated the actinide material became molten during the irradiation and underwent material flow.…”

“…We observed changes in the physical structure of the actinide deposits that indicated the actinide material became molten during the irradiation and underwent material flow. (This work was done using AFM imaging and electron microscopy [8]). There was some indication of sputtering of material from the target, with the sputtered material having a composition of U 2 F x with x = 7-8.…”

“…Whether that represents a difficulty in using these targets is not clear. For example, with actinide targets prepared by vacuum volatilization, one generally expects (and observes [8] ) that the actinide deposit has the formula AnF 4 (where An represents the actinide element) and the backing material is well characterized. The chemical composition of these targets seems to be adequately described.…”

High-power radioactive targets as one of the key problems in further development of the research program on synthesis of new superheavy elements

“…The thickness of the target can be determined either by weighing and/or employing a-, c-spectroscopy. The application of neutron activation analysis, scanning electron microscope, back scattering of protons, and radiographic imaging for the characterization of deposited layers of lanthanide and actinide elements for elaboration of new methods and study effects of irradiation on morphological and chemical composition of targets, is described in [21][22][23]. The earlier cited publications [13,17,18,20] contain more detailed information on specific experimental procedures.…”