#4 Molecular Beam, Praxis
This 6-liter stainless steel chamber is evacuated with a 300 l/s turbomolecular pump to a base pressure in the E-10 Torr range. The chamber is equipped with a Specs IQE 10/35 sputtering gun, an UTI 100C mass quadrupole (placed out of line-of-sight), and an effusive molecular beam consisting of a 1.2 cm diameter multichannel array. The gas flux is fixed by setting both the leak valve and the backing gas pressure, which is measured by a MKS Baratron (PDR-C-1C) pressure gauge. A movable stainless steel flag is placed between the doser and the sample to intercept the beam at will. The sample is mounted in a x-y-z-q centered manipulator capable of resistively heating to up to > 1300 K and of cooling to < 90 K by using a liquid nitrogen reservoir. The temperature of the sample is measured by a thermocouple spot-welded to the side of the sample and regulated by a homemade AC controller.
Techniques: TPD, Isothermal kinetic measurements