title: Nanoparticle dispersion in superfluid helium.
abstract: Cryogenic fluid flows including liquid nitrogen and superfluid helium are a rich environment for novel scientific discovery. Flows can be measured optically and dynamically when faithful tracer particles are dispersed in the liquid. We present a reliable technique for dispersing commercially available fluorescent nanoparticles into cryogenic fluids using ultrasound. Five types of fluorescent nanoparticles ranging in size from 5 nm to 1 μm were imaged in liquid nitrogen and superfluid helium, and were tracked at frame rates up to 100 Hz.
authors.affiliation: Department of Physics, Institute for Research in Electronics and Applied Physics, and Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: David P
authors.initials: DP
authors.lastname: Meichle
authors.affiliation: Department of Physics, Institute for Research in Electronics and Applied Physics, and Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Lathrop