Ultra-High Vacuum (UHV) Experiments

There are two options for experiments requiring UHV sample conditions: the large UHV chamber in EH2 or the "baby chamber" in EH1.

The second experimental hutch houses a diffractometer with a large UHV chamber. The hutch allows longer term UHV setup and in-situ sample preparation to take place while other users take beam in the first hutch.

This chamber houses a wide range of UHV surface science, preparation and characterisation equipment including sputter guns and LEED/AES optics. Additionally, a number of ports (CF38) are available for mounting evaporation sources, enabling in-situ growth dynamics to be studied as well as well ordered surface arrangements.

Typical operating conditions:

Details of equipment in EH2:

• (2+3)-circle diffractometer with hexapod sample stage for use with the sample vertical (surface normal horizontal)
• Large ultra high vacuum sample chamber for in-situ preparation and characterisation using standard surface science techniques
• LEED/AES
• Pressure ~ 1x10^-11 mbar
• E-beam heating up to ~2300 K in analysis chamber
• Resistive heating up to ~ 900 K in buffer chamber
• Heating in pressures up to 10^-4 mbar of oxygen
• Pilatus 100K detector

The UHV baby chamber is a small, portable UHV system that can be used in EH1 in vertical scattering geometry. This sample environment is designed for high flexibility and allows for temperature control (room temperature to 900°C) and pressure control. It permits the use of pressures from UHV conditions up to atmospheric pressure, and enables the use of samples that are not normally allowed in the EH2 UHV system. This setup is also very practical for experiments that require UHV preparation followed by measurement in ambient pressure conditions.

The system is equipped with interchangeable Be windows mounted on a CF63 flange, which make the system adaptable to different types of experiments. The system has 3 possible configurations:

Specifications for the baby chamber are as follows: