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q uartz transducers

Propagating Ultrasound in Supersolid He-4 Haruo Kojima, Rutgers University New Brunswick, DMR 1005325.

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q uartz transducers

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  1. Propagating Ultrasound in Supersolid He-4Haruo Kojima, Rutgers University New Brunswick, DMR 1005325 Does a solid He-4 sample cooled down below 300 mK become a superfluid or not? Torsional oscillator experiments answer yes since solid He-4 seems to partially decouple from its rotating container. There important unsettled questions. Why does the amount of decoupling vary so much on sample quality? Why is it so sensitive to miniscule He-3 impurity added? The sample quality of solid He-4 is determined by the number of dislocation lines and crystalline grain boundaries. Ultrasound propagation can act as non-destructive probe to measure the presence of dislocation lines. A new apparatus (see Fig. 1) has been built to simultaneously study ultrasound and torsional oscillation. Preliminary measurements show dislocation lines and torsion phenomena are closely relatedto each other. torsion rod sample chamber torsion detector fin quartz transducers Fig. 1. Exposed schematic view of ultrasound detection system mounted into torsional oscillator. The ends of the sample chamber are fitted with 10 MHz quarts transducers. The velocity and attenuation of ultrasound are measured simultaneously with the frequency and dissipation of the torsional oscillator resonance mode.

  2. Propagating Ultrasound in Supersolid He-4HaruoKojima, Rutgers University New Brunswick, DMR 1005325 Victoria Yu (junior physics major), ParthJariwala (junior engineering major) and Jennifer Yu (senior physics major) all played active roles by participating in research. Rebecca Cebulka recently joined the group as an Aresty Research intern. The PI was a co-organizer of the international workshop on supersolidity in New York City in June 2011. Victoria Yu presented her research on a search for fourth sound at the Aresty Undergraduate Research Symposium. Jennifer Yu delivered her senior honors thesis presentation to the physics department ParthJariwala proudly displays his completed design of triple compound torsional oscillator for measuring dynamical response of supersolid He-4.

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