Investigation of ultrasound attenuation in impurity-helium solids containing liquid helium. Academic Article uri icon

abstract

  • The attenuation of ultrasound in Impurity-Helium (Im-He) solids created upon introduction of impurity atoms or molecules (D2, N2, Kr) into a volume of superfluid helium has been investigated. The observed features of attenuation show that a porous substance consisting of a loosely interconnected continuous network is created in superfluid helium. This network is formed by impurity particles encapsulated in solidified helium. Analysis of attenuation allows us to conclude that Im-He solid samples have a wide distribution of pores from 8 nm to 800 nm. It was established that the character of attenuation in D2-He samples is considerably different from that in heavier Im-He solids, for which two maxima of attenuation were sometimes observed. A sharp peak was observed at Tc0very close to the bulk helium lambda transition temperature and a second broad peak occurred at Tc< Tc0. This behavior is similar to that predicted theoretically for liquid helium in restricted fractal porous media.

published proceedings

  • JOURNAL OF LOW TEMPERATURE PHYSICS

author list (cited authors)

  • Kiselev, S. I., Khmelenko, V. V., & Lee, D. M.

complete list of authors

  • Kiselev, SI||Khmelenko, VV||Lee, DM

publication date

  • January 1, 2000 11:11 AM