October AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | O C T O B E R 2 0 1 9 1 3 TOMOSCOPY FOAMING WITH SPEED Scientists at the Helmholtz-Ze- ntrum Berlin (HZB), Germany, have achieved a world record with their pre- cision rotary sample table. The new table rotates around its axis at sev- eral hundred revolutions per second with extreme precision, and in 2018 it reached over 25 tomographic images per second using the BESSY II EDDI beamline. To accomplish this feat, the HZB team, together with a group from the Paul Scherrer Institute (PSI), Switzer- land, set up the rotary sample table with improved optics and used ultra- fast image acquisition as well as data transfer rates at the SLS’s TOMCAT instrument. The term “tomoscopy” was coined for this new imaging method. Each individual image must be calculated from the measurement data. The images then receive additional automatic processing that facilitates quantitative analysis. In order to han- dle the processing of several terabytes of data from each experiment, HZB scientists developed and implemented unique dedicated processing software. The partners in this collabora- tion used the new imaging method to observe dynamic processes in great detail at the high temporal resolution that occurs during the foaming of liquid aluminum. Metal foams are an important class of materials for lightweight con- struction, and they are a good fit for the newly developed imaging method. Liq- uid metal is largely insensitive to radi- ation damage, and the imaging speeds achieved are extremely well-suited to foaming phenomena. Ultrafast computer tomoscopy could also provide interesting insights into many other processes. For exam- ple, it could be used to investigate how materials change during laser welding or what happens when batteries over- heat due to short circuits. The researchers at the HZB and PSI are now working on increasing the rotational speed in order to further increase the temporal resolution of the measurements. www.helmholtz-berlin. de, www.psi.ch/en. Precision rotary sample table. Courtesy of HZB.