Sample specifications

Samples must be ultra-high vacuum compatibles. The PEEM usually operates at pressures better than 1x10^-9 mbar under 20kV of accelerating voltage and, hence, any material that degasses is not allowed.

Sample surfaces must be CONDUCTIVE. There is no possibility of imaging insulating surfaces because of charging effects. Ultra-thin oxide layers on metals and doped semiconductors can be used, as well as ultrathin conductive capping layers (usable for threshold PEEM and XPEEM only!). In case of doubt, please ask your local contact.

Sample are mounted on specific holders (cartridges) and kept in position with Mo-caps as shown in the schematic design of figure 1. The outer diameter of the cap is 14 mm ;  the inner one may vary between 2 mm to 10 mm.  The thickness of the sample should not exceed 2 mm. Lateral dimensions are limited to 10 x 10 mm². Samples smaller than ~ 4 x 4 mm² can be mounted using UHV compatible conductive glue. Please contact beamline staff for more details.

Fig. 1: Left: Elmitec standard cartridge. Right: Schematic drawing of the range of suitable sample sizes.