Kapitza resistance between superfluid helium and solid: Role of the boundary

Amrit, Jay; Ramière, Aymeric

doi:10.1063/1.4821076

Cited by 4 publications

(4 citation statements)

References 10 publications

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“…Our results, shown in figures 13 and 14, are consistent with data in the literature, where several authors observed that the heat transfer from Cu surfaces to He-I is generally affected by the surface roughness [31][32][33]. This is also observed in He-II in many cases [34,35].…”

Section: Heat Dissipation In Thin Film Coated Copper Rf Cavitiessupporting

confidence: 91%

Temperature measurement on copper surfaces for superconducting thin film cavity applications

Bianchi,

Vandoni,

Venturini Delsolaro

2023

Meas. Sci. Technol.

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Superconducting radio-frequency (SRF) thin film cavities on copper substrates are employed in several particle accelerators. However, these SRF cavities historically featured a progressive performance degradation with the accelerating field that is still not completely understood. The degradation of cavity performance, which limits the use of this technology in accelerators where the real-estate gradient has to be maximized, is manifested by the presence of heat losses in the superconducting film. However, measuring the temperature on the outer surface of copper substrates is challenging due to the higher thermal conductivity of copper at low temperatures compared to niobium. This study describes how temperature variations on copper surfaces can be satisfactorily measured in view of superconducting thin film cavity applications at liquid helium temperatures. Furthermore, we explore how the thermal exchange between thermometers and copper surfaces, and thermometers and helium bath must be tuned with respect to each other in order to measure accurately temperature rises in the thin film. Our findings suggest that engineering the copper surfaces can improve heat transfer into the helium bath and potentially enhance the performance of thin film SRF cavities.

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Section: Heat Dissipation In Thin Film Coated Copper Rf Cavitiessupporting

confidence: 91%

Temperature measurement on copper surfaces for superconducting thin film cavity applications

Bianchi,

Vandoni,

Venturini Delsolaro

2023

Meas. Sci. Technol.

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“…Our results, shown in figures 13 and 14, are consistent with data in the literature, where several authors observed that the heat transfer from Cu surfaces to He-I is generally affected by the surface roughness [30][31][32]. This is also observed in He-II in many cases [33,34].…”

Section: B Heat Dissipation In Thin Film Coated Copper Rf Cavitiessupporting

confidence: 91%

Niobium thin film deposition studies on copper surfaces for superconducting radio frequency cavity applications

Roach

Beringer

Skuza

et al. 2012

Phys. Rev. ST Accel. Beams

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Thin film coatings have the potential to increase both the thermal efficiency and accelerating gradient in superconducting radio frequency accelerator cavities. However, before this potential can be realized, systematic studies on structure-property correlations in these thin films need to be carried out since the reduced geometry, combined with specific growth parameters, can modify the physical properties of the materials when compared to their bulk form. Here, we present our systematic studies of Nb thin films deposited onto Cu surfaces to clarify possible reasons for the limited success that this process exhibited in previous attempts. We compare these films with Nb grown on other surfaces. In particular, we study the crystal structure and surface morphology and their effect on superconducting properties, such as critical temperature and lower critical field. We found that higher deposition temperature leads to a sharper critical temperature transition, but also to increased roughness indicating that there are competing mechanisms that must be considered for further optimization.

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“…In this regard, numerous experiments were carried out by different authors in which the role of a solid surface in heat transfer between solid and superfluid helium was investigated. The results of such experiments are given in the review [5] and in later experimental works [6][7][8][9]. These experiments indicated that the condition of a solid surface does substantially alter the heat transfer coefficient so that it becomes larger than only an order of magnitude of the coefficient calculated in theory [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Interaction of phonons at superfluid helium - solid interfaces

Adamenko¹,

Nemchenko²

2014

Condens. Matter Phys.

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A new method of obtaining the interaction Hamiltonian of phonons at superfluid helium-solid interface is proposed in the work. Equations of hydrodynamic variables are obtained in terms of second quantization if helium occupies a half-space. The contributions of all processes to the heat flux from solid to superfluid helium are calculated based on the obtained Hamiltonian. The angular distribution of phonons emitted by a solid is found in different processes. It is shown that all the exit angles of superfuild helium phonons are allowed. The obtained results are compared with experimental data and with previous theoretical works.

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Kapitza resistance between superfluid helium and solid: Role of the boundary

Cited by 4 publications

References 10 publications

Temperature measurement on copper surfaces for superconducting thin film cavity applications

Temperature measurement on copper surfaces for superconducting thin film cavity applications

Niobium thin film deposition studies on copper surfaces for superconducting radio frequency cavity applications

Interaction of phonons at superfluid helium - solid interfaces

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