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A simple design for an inexpensive, cooled, free-jet beam source is described. The source assembly features an integrated cooling system as supplied by a counter-flow of chilled nitrogen, and is composed primarily of off-the-shelf tube fittings. The design facilitates rapid implementation and eases subsequent alignment with respect to any downstream beamline aperture. The source assembly outlined cools the full length of the stagnation volume, offering temperature control down to 100 K and long-term temperature stability better than ± 1 K. [ABSTRACT FROM AUTHOR]

We present a scanning helium microscope equipped to make use of the unique contrast mechanisms, surface sensitivity, and zero damage imaging the technique affords. The new design delivers an order of magnitude increase in the available helium signal, yielding a higher contrast and signal-to-noise ratio. These improvements allow the microscope to produce high quality, intuitive images of samples using topological contrast, while setting the stage for investigations into further contrast mechanisms. [ABSTRACT FROM AUTHOR]