Search

A novel design of a scanning tunneling microscope (STM) for surface science studies is described. The STM is fully compatible with ultrahigh vacuum (UHV) and offers the possibility of performing individual STM scans over a large region of the sample surface (≂10 mm2). The sample coarse approach is realized by a fine pitch screw, which shifts two wedges against each other. In order to incorporate the STM in an UHV system for the standard preparation and analyzing techniques of surface science, a special sample holder and sample transfer system has been developed. For defined heating of the sample, disconnectable electrical wiring for both a resistively heated oven and a thermocouple has been integrated within the sample holder.

The authors have developed a magnet‐type tip transfer system for use in an ultrahigh vacuum scanning tunneling microscopy/field ion microscopy (UHV‐STM/FIM) system. The construction of the tip transfer system ensures that a tip can be introduced into the STM and the FIM in situ without any chances of tip crushing during handling. The new tip transfer system is extremely simple and reliable, and is particularly suitable for rapid tip exchange in the STM. An atom‐resolved image of a highly oriented pyrolytic graphite has been obtained with a tungsten tip characterized by an FIM and transferred to an STM via this transfer system.

An optimized automated liquid helium transfer system diverts warm gas from entering the cryostat, saves on liquid helium consumption, reduces man hours, and enhances safety. Control electronics, cryogenic valves and a multipiped transfer line are also discussed.

A simple, inexpensive, and flexible sample transfer system is described. The system possesses the advantages of excellent base pressure and the flexibility to study thin films deposited in situ. We have applied the system to study thin‐film magnetism with magnetic measurements utilizing optical techniques that require stable sample support.

An air-look system has been developed in order to transfer reactive samples under vacuum from any preparation facility to the high-resolution stage of the Philips EM 300S electron microscope. The system has been tested using the highly hygroscopic material strontium chloride prepared in the form of small particles. Based on the shape of the particles and the associated diffraction pattern, it has been shown that the air-lock transfer system effectively prevents hydration in the case of small SrCl(2) particles.

The design of a UHV sample transfer system is described. The transfer system allows irradiation of samples under vacuum in a laboratory physically removed from the location of the surface analysis system. Design considerations and advantages of this design are discussed.

An inexpensive sample transfer system suitable for surface studies with in situ prepared model catalysts is described. Experiments from ultrahigh vacuum to 10 atm and 50‐cm travel with negligible pressure spikes were made possible by the use of double‐seal glands with spring‐loaded Teflon O‐rings and a guided rotational transport rod.

The design of an assembly to transfer a surface barrier detector into and out of a UHV chamber is described.

A simple system is described for automatic control of the liquid helium transferred to cool down a cryostat when using hydrogen exchange gas. The system not only frees personnel from tending to this (typically) 4 h task, but makes it impossible to collect liquid in the Dewar until the apparatus is sufficiently cold.