Micrometer-sized nozzles and skimmers for the production of supersonic He atom beams

Abstract

Micrometer-sized nozzles and skimmers made from drawn glass tubes are described and tested for the production of highly monoenergetic He atom beams. Glass nozzles with diameters between 1 μm and 4 μm when operated at He source stagnation pressures of up to 1000 atm provide intense beams with measured speed ratios of S=50–100, in good agreement with the predicted behavior scaled from nozzles with larger openings. Miniature glass skimmers with diameters as small as 3 μm were also successfully tested with conventional 10 μm diameter nozzles. These miniature nozzle-beam sources can be used to greatly reduce the size of present-day He-atom surface-scattering time-of-flight spectrometers and to reduce the number of vacuum stages and the size of vacuum pumps. They also open up new experimental possibilities as illustrated by measurements of the spatial profiles of seeded nozzle beams.