Münster 2017 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 27: Poster
HK 27.89: Poster
Tuesday, March 28, 2017, 16:45–18:45, F Foyer
Damages of plunger targets due to swift heavy ion irradiation — •Christoph Fransen, Andrey Blazhev, Thomas Braunroth, Alfred Dewald, Alina Goldkuhle, Claus Müller-Gatermann, Dorothea Wölk, and Karl-Oskar Zell — Institut für Kernphysik, Universität zu Köln
For lifetime measurements of excited nuclear states with the recoil distance
Doppler-shift (RDDS) method and the plunger target foils with very good surface qualities,
i.e., roughnesses in the micrometer range, are often essential. Therefore,
these targets are typically stretched over highly precisely made cones and
careful estimates on the target temperature in the beam spot are required
to avoid the formation of bumps in these foils due to beam-induced heating
up caused by the energy transfer.
However, when performing RDDS experiments with heavy ion beams with
energies of several MeV/u an additional effect must be considered: the
sensitivity of several (metallic) target materials to the electronic
stopping power (Se) of swift heavy ions causing structural changes [1].
This effect is known in material science since several years, but in RDDS
experiments it was only observed in very recent experiments by our group
where extreme wrinkles appeared in some target foils with
amplitudes of the order of 100 µm. Such can hamper a RDDS measurement
completely. Based on the results and predictions in [1,2] we will discuss
these observations with respect to the choice of target materials including
the use of multilayer targets.
[1] Z.G. Wang, et al., J. Phys. Condens. Matter 6 (1994) 6733
[2] M. Toulemonde et al, Nucl. Instr. Meth. B 277 (2012) 28