Thermal boundary resistance in superfluid4He nearT ?

Murphy, Daniel; Meyer, Horst

doi:10.1007/bf00754633

Cited by 15 publications

(10 citation statements)

References 19 publications

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“…Care was taken to ensure that the gap between the top endplate and the sidewall was filled with epoxy, since there is a heat flux dependent Kapitza resistance when helium is allowed to penetrate between the endplate and the sidewall [14,15]. However, because the bottom endplate was epoxied last, we were unable to examine its gap.…”

Section: Cell Constructionmentioning

confidence: 99%

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Experiments on the Self-Organized Critical State of 4He

Chatto

Lee

Duncan³

et al. 2007

J Low Temp Phys

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AcknowledgementsThere are a number of people I would like to thank for their contributions to this thesis. My advisor David Goodstein was insightful, encouraging, and patient throughout the many challenges of performing a low-temperature experiment. Our conversations were always helpful because David has an extraordinary ability to make complicated concepts seem simple and intuitive. I had two mentors in the lab, Peter Day and Richard Lee, who taught me everything I know about performing experiments in low-temperature physics. My first lab experience was working with Peter. He provided me with the cryostat I used throughout my graduate career, answered hundreds of questions, and patiently showed me the techniques I needed. Richard returned to Caltech as my thesis experiment was taking shape. He was also an excellent resource for the tricks and techniques of low-temperature physics. (Plus, he made B.O.B.2, the electrical filtering system on this cryostat). However, what helped me most was that he patiently asked hundreds of questions, which forced me to think through all the details of my experiment. It is with his help that I avoided many pitfalls.There are a number of other physicists who made significant contributions to this work. Particularly helpful were the members of the DYNAMX team from the University of New Mexico (Rob Duncan, Dimitri Sergatskov, Alex Babkin, and Steve Boyd). They provided material help with the cryo-valve system and the construction of the experimental cell. In addition, they provided a lot of expertise on performing experiments on the SOC state of 4 He. In particular, I would like to thank Rob Duncan, who served as a secondary thesis advisor during a critical time in the experiment as David Goodstein recovered from an injury. Also helpful were discussions with two theorists, Peter Weichman and Rudolf Haussmann, who helped give meaning to my results.I would like to thank my parents for many many years of encouragement and support, and not asking me too often when I was going to get my degree.I would also like to thank my wife Avital, who provided an enormous amount of support and, through an intricate dance of prodding and patience, helped guide me through this endeavor. Lastly, I thank my son Jacob, whose arrival helped destroy the illusion that maybe, just maybe, I could be a graduate student forever. We report the first results of the heat capacity of the SOC state, C ∇T , for heat fluxes 60nW/cm 2 < Q < 13 µW/cm 2 and corresponding temperatures 9 nK > T SOC − T λ > −1.1 µK. We find that C ∇T tracks the static (i.e., zero heat flux) unrounded (i.e., in zero gravity) heat capacity C 0 with two exceptions. The first is that within 250 nK of T λ , C ∇T is depressed relative to C 0 and the maximum in C ∇T is shifted to 50 nK below T λ . The second difference is that at high heat flux, C ∇T is again depressed relative to C 0 with the departure starting at about 650 nK below T λ .We present the most extensive measurements of the speed and attenuation of the SOC wave to date. We report wav...

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Section: Cell Constructionmentioning

confidence: 99%

“…Unfortunately, we measured a heat-flux-dependent resistance. This is caused by having helium in the gap between the endplate and the sidewall [14,15]. As discussed in sec.…”

Section: Kapitza Resistancementioning

confidence: 99%

Experiments on the Self-Organized Critical State of 4He

Chatto

Lee

Duncan³

et al. 2007

J Low Temp Phys

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“…7-8 are the measured the density responses, Zp, at the two sensor locations, compared with the calculation ZF of Eqs. (11) and (27). In the calculation of ZF, the distance between the density sensor and endplate is taken to be 0.9 mm for a better agreement on the peak location than the nominal 1.0 mm as originally designed.…”

Section: Resultsmentioning

confidence: 99%

“…The effective reduced width A of each capacitor for the averaging in Eq. (27) was taken to be A----0.094, based on the thickness of the stainless steel blades and the capacitor gap. No correction from the fluid enclosure is made in the calculation of ZF(Z, q) because of its smallness, as discussed in Appendix B.…”

Section: Resultsmentioning

confidence: 99%

“…First, we note that the capacitive density sensors have a finite sampling width hA. By averaging the ~(co, z) from z-h A/2 to z + h A/2, we obtain ~a(z, q) =~(F) +(I --e(F)) cos q(2z/h -1) sin qA cos q qA (27) As we have seen before, the density response is independent of the position in the cell interior at high frequencies (See Figs. 3 and 4).…”

Section: Op(co) = A(co) E I*'~'lmentioning

confidence: 99%

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Thermal response of a fluid near its critical point:3He atT>T c

1997

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Heat transport in dilute mixtures of3He in superfluid4He

Murphy

Meyer

1997

J Low Temp Phys

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We report new measurements of the effective thermal comhtetivity K,,t~ and rehtxation t#ne r in dilute mixtures of ~He in superjluid 4He, with mohu" concentrations X <~ 10 s. The temperature range extended fi'om T ~ 1.4 K to T;. Both ~",:t/ and r are found to agree with theoretical predictions, in contrast to previous experhnents where significant diJferences were observed. A new thermal comhtctivi O, cell design was used which ahnost comph, tely eliminates extraneous vohmws and surJ;tces, and the earlier results are e,\plahled h7 relation to these design changes.

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Thermal boundary resistance in superfluid4He nearT ?

Cited by 15 publications

References 19 publications

Experiments on the Self-Organized Critical State of 4He

Experiments on the Self-Organized Critical State of 4He

Thermal response of a fluid near its critical point:3He atT>T c

Heat transport in dilute mixtures of3He in superfluid4He

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