相关论文: Magnetic Flux Dynamics in Horizontally Cooled Supe…
Even when cooled through its transition temperature in the presence of an external magnetic field, a superconductor can expel nearly all external magnetic flux. This Letter presents an experimental study to identify the parameters that most…
We report a strong effect of the cooling dynamics through $T_\mathrm{c}$ on the amount of trapped external magnetic flux in superconducting niobium cavities. The effect is similar for fine grain and single crystal niobium and all surface…
For many new accelerator applications, superconducting radio frequency (SRF) systems are the enabling technology. In particular for CW applications, much effort is being expended to minimize the power dissipation (surface resistance) of…
When a superconducting radiofrequency cavity is cooled through its critical temperature, ambient magnetic flux can become "frozen in" to the superconductor, resulting in degradation of the quality factor. This is especially problematic in…
Cool-down dynamics of superconducting accelerating cavities became particularly important for obtaining very high quality factors in SRF cavities. Previous studies proved that when cavity is cooled fast, the quality factor is higher than…
Magnetic flux trapped during the cooldown of superconducting radio-frequency cavities through the transition temperature due to incomplete Meissner state is known to be a significant source of radio-frequency losses. The sensitivity of flux…
Controlling trapped magnetic flux in superconducting radiofrequency (RF) cavities is of crucial importance in modern accelerator projects. In order to study flux trapping efficiency and sensitiv- ity of surface resistance, dedicated…
Magnetic flux trapping in the Meissner transition of superconducting radio frequency cavities can substantially increase dissipation which impacts cryogenic costs and necessitates expensive magnetic shielding. Recent findings point at the…
During the cool-down of a superconducting accelerating cavity, a magnetic flux is trapped as quantized vortices, which yield additional dissipation and contribute to the residual resistance. Recently, cooling down with a large spatial…
The trapped residual magnetic flux during the cool-down due to the incomplete Meissner state is a significant source of radio frequency losses in superconducting radio frequency (SRF) cavities. Here, we show a clear correlation between the…
Magnetic flux expulsion properties of the superconducting material such as bulk niobium, widely used for the radio-frequency cavity fabrication, substantially affect the performance characteristics of the cavities. The quality factor of the…
The main source of RF losses leading to lower quality factor of superconducting radio-frequency cavities is due to the residual magnetic flux trapped during cool-down. The loss due to flux trapping is more pronounced for cavities subjected…
The flux trapping that occurs in the process of cooling down of the superconducting cavity is studied. The critical fields $B_{c2}$ and $B_{c1}$ depend on a position when a material temperature is not uniform. In a region with $T\simeq…
It is found that the magnetization curves of samples of fragments of cathode carbon deposits with a high content of multiwalled nanotubes exhibit a pronounced irreversible character, attesting to the induction of persistent currents in the…
This paper reports on a surface impedance measurement of a niobium titanium superconducting radio frequency (SRF) cavity in a magnetic field (up to $10\,{\rm T}$). A novel method is employed to decompose the surface resistance contributions…
A series of experiments were carried out in an effort to develop a simple method for predicting magnetic flux expulsion behavior of high purity niobium used to fabricate superconducting radio frequency (SRF) cavities. Using conventional…
Superconducting radio-frequency cavities are commonly used in modern particle accelerators for applied and fundamental research. Such cavities are typically made of high-purity, bulk Nb and are cooled by a liquid helium bath at a…
Expulsion of ambient flux has been shown to be crucial to obtain high quality factors in bulk niobium SRF cavities. However, there remain many questions as to what properties of the niobium material determine its flux expulsion behavior. In…
Upcoming projects requiring high-Q ~650 MHz medium-to-high-${\beta}$ elliptical cavities drive a need to understand magnetic RF loss mechanisms and mitigations in greater detail. High-temperature annealing and fast-cooldowns have proven…
Macroscopic superconducting components are an important building block of various quantum circuits. Since several of the envisioned applications require exposure to magnetic fields, it is of utmost importance to explore the impact of…