HZB, Berlin, Germany
HZB, Berlin, Germany
University of Siegen, Siegen, Germany
KEK, Ibaraki, Japan
HZB, Berlin, Germany
University of Siegen, Siegen, Germany
KEK, Ibaraki, Japan
HZB, Berlin, Germany
University of Siegen, Siegen, Germany
| Paper | Title | Page |
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| MOPMB010 | Analysis of Semiconductor Components as Temperature Sensors for Cryogenic Investigation of SRF Materials | 80 |
| SUSPB006 | use link to see paper's listing under its alternate paper code | |
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| Temperature mapping systems have been used for many years to detect local heating in an SRF cavity surface or materials sample. They require a large number of temperature sensors. Most often, low-cost Allen-Bradley resistors are used for this purpose. Since they have poor sensitivity and reproducibility above 4 K, sensor alternatives that combine the precision of Cernox sensors with the low-cost of Allen-Bradley resistors would be highly desirable. In this work various semiconductor components that exhibit a temperature dependent electrical response, such as diodes and LEDs were analyzed with respect to sensitivity, reproducibility and response speed in a temperature range between 6.5 K and 22 K. In this range, many diodes and LEDs were found to be more sensitive than Cernox sensors. However, in some components the response time was slow - possibly due to poor thermal contact. | ||
| DOI • | reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB010 | |
| About • | Received ※ 08 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 17 July 2023 | |
| Cite • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUCXA01 | Study of the Dynamics of Flux Trapping in Different SRF Materials | 380 |
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| A dedicated experimental setup to measure magnetic flux dynamics and trapped flux in samples is used to precisely map out how trapped flux is influenced by different parameters. The setup allows for rapid thermal cycling of the sample so that effects of cooldown parameters can be investigated in detail. We show how temperature gradient, cooldown rate, and the magnitude of external field influence trapped flux in large grain, fine grain and coated niobium samples. The detailed measurements show unexpected results, namely that too fast cooldowns increase trapped flux, large grain material traps flux only when the external field is larger than a temperature gradient dependent threshold field, and the measured dependence of trapped flux on temperature gradient does not agree with an existing model. Therefore, a new model is presented which agrees better with the measured results. | ||
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Slides TUCXA01 [3.180 MB] | |
| DOI • | reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUCXA01 | |
| About • | Received ※ 17 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 26 June 2023 | |
| Cite • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPTB002 | Modelling Trapped Flux in Niobium | 393 |
| SUSPB017 | use link to see paper's listing under its alternate paper code | |
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| Detailed measurements of magnetic flux dynamics and trapped magnetic flux in niobium samples were conducted with a new experimental setup that permits precise control of the cooldown parameters. With this setup the dependency of trapped flux on the temperature gradient, external magnetic field, and cooldown rate can be mapped out in more detail compared to cavity measurements. We have obtained unexpected results, and an existing model describing trapped flux in dependence of temperature gradient does not agree with the measured data. Therefore, a new model is developed which describes the magnitude of trapped flux in dependence of the temperature gradient across the sample during cooldown. The model describes the amount of trapped flux lines with help of a density distribution function of the pinning forces of pinning centers and the thermal force which can de-pin flux lines from pinning centers. The model shows good agreement with the measured data and correctly predicts trapped flux at different external flux densities. | ||
| DOI • | reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB002 | |
| About • | Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023 | |
| Cite • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPTB013 | Commissioning of a New Sample Test Cavity for Rapid RF Characterization of SRF Materials | 410 |
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| RaSTA, the Rapid Superconductor Test Apparatus, is a new sample test cavity that is currently being commissioned at HZB. It uses the established QPR sample geometry but with a much smaller cylindrical cavity operating in the TM020 mode at 4.8 GHz. Its compact design allows for smaller cryogenic test stands and reduced turnaround time, enabling iterative measurement campaigns for thin film R&D. Using the same calorimetric measurement technique as known from the QPR allows direct measurements of the residual resistance. We report first prototype results obtained from a niobium sample that demonstrate the capabilities of the system. | ||
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Poster TUPTB013 [0.464 MB] | |
| DOI • | reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB013 | |
| About • | Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 28 June 2023 | |
| Cite • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |