Sample Prepartion

To create near defect free and highly reproducible Si(111)-7x7 surfaces with a chosen coverage of adsorbate molecule.

Our LabVIEW computer program (reasonably) intelligently controls the sample baking, flashing and reconstruction, while continuously monitoring the pressure and sample temperature.  Then once the Si-crystal is cleaned and cooled, the LabVIEW program will open a selected leak-valves and dose just the right amount of gas to create a certain coverage of adsorbate molecule on the clean surface. When the operator arrive with their coffee in the morning they have little or no excuse not to get on with some science. We also have access to our preparation computer off campus.

The original LabVIEW code was written by Dr Iain R. McNab who was also in the group of Polanyi. As Iain put it, "if you perform the same task more than ten times you should automate it". So he took my recipe for preparing Si(111)7x7 crystals developed at Birmingham University and set it to LabVIEW. I then developed the code a bit further upon my return to Birmingham and then re-wrote from the ground up once at Bath.

The program controls our high-current power source (TDK Lambda Gen 60-12.5) for the flashing and uses an Active-Robots stepper motor controller to control upto 4 stepper motors which we have bolted to our UHV leak-valves using an adapter originally  designed at Birmingham and modified at Bath by Paul Frith.

The code is by no means perfect but does a good job and is (reasonably) adaptable to allow control of other power supplies etc. For example we also have it working also with an Agilent power supply. We always check there are LabVIEW VIs ready to use to control and communicate with a new piece of equipment, it just save time and hassle.

If you would like a copy of the code please e-mail (p.sloan@bath.ac.uk).