arXiv subjects

M. Wenskat

Publications and source records attributed to M. Wenskat.

4 recordsLinked to original sources

arXiv2026

Detection of high-frequency gravitational waves using SRF cavities

Today, apart from some isolated R&D efforts, there are no gravitational wave (GW) experiments, yet which explore a large part of the vast frequency range above the LIGO/Virgo band. It is planned to establish an experiment at Deutsches Elektronen-Synchrotron (DESY) and at the Superconducting Quantum Materials and Systems (SQMS) Center at Fermi National Accelerator Laboratory (Fermilab) to search for high-frequency GWs in the frequency range of 10 kHz to 100 MHz. The basic idea is to use superconducting radiofrequency (SRF) cavities to detect tiny harmonic deformations induced by GWs which change the boundary conditions of the oscillating electromagnetic field. This paper summarizes the challenging environmental boundary requirements, and the R&D to operate a cavity using a low level RF (LLRF) system which pushes beyond state-of-the-art accuracy and resolutions and a seismic noise mitigated cryostat at 1.8 K. The focus of this paper is the warm and cold commissioning of a prototype cavity, built 20 years ago during the MAGO collaboration, and its first measurement in our collaborative research project.

physics.acc-ph↗

arXiv2022

Key directions for research and development of superconducting radio frequency cavities

Radio frequency superconductivity is a cornerstone technology for many future HEP particle accelerators and experiments from colliders to proton drivers for neutrino facilities to searches for dark matter. While the performance of superconducting RF (SRF) cavities has improved significantly over the last decades, and the SRF technology has enabled new applications, the proposed HEP facilities and experiments pose new challenges. To address these challenges, the field continues to generate new ideas and there seems to be a vast room for improvements. In this paper we discuss the key research directions that are aligned with and address the future HEP needs.

physics.acc-ph↗

arXiv2022

Next-Generation Superconducting RF Technology based on Advanced Thin Film Technologies and Innovative Materials for Accelerator Enhanced Performance and Energy Reach

Superconducting RF is a key technology for future particle accelerators, now relying on advanced surfaces beyond bulk Nb for a leap in performance and efficiency. The SRF thin film strategy aims at transforming the current SRF technology by using highly functional materials, addressing all the necessary functions. The community is deploying efforts in three research thrusts to develop next-generation thin-film based cavities. Nb on Cu cavities are developed to perform as good as or better than bulk Nb at reduced cost and with better thermal stability. Recent results showing improved accelerating field and dramatically reduced Q slope show their potential for many applications. The second research thrust is to develop cavities coated with materials that can operate at higher temperatures or sustain higher fields. Proof of principle has been established for the merit of Nb3Sn for SRF application. Research is now needed to further exploit the material and reach its full potential with novel deposition techniques. The third line of research is to push SRF performance beyond the capabilities of the superconductors alone with multilayered coatings. In parallel, developments are needed to provide quality substrates, cooling schemes and cryomodule design tailored to thin film cavities. Recent results in these three research thrusts suggest that SRF thin film technologies are at the eve of a technological revolution. For them to mature, active community support and sustained funding are needed to address fundamental developments supporting material deposition techniques, surface and RF research, technical challenges associated with scaling and industrialization. With dedicated and sustained investment, next-generation thin-film based cavities will become a reality with high performance and efficiency, facilitating energy sustainable science while enabling higher luminosity, and higher energy.

physics.acc-ph↗

arXiv2021

Mitigation of parasitic losses in the quadrupole resonator enabling direct measurements of low residual resistances of SRF samples

The quadrupole resonator (QPR) is a dedicated sample-test cavity for the RF characterization of superconducting samples in a wide temperature, RF field and frequency range. Its main purpose are high resolution measurements of the surface resistance with direct access to the residual resistance thanks to the low frequency of the first operating quadrupole mode. Besides the well-known high resolution of the QPR, a bias of measurement data towards higher values has been observed, especially at higher harmonic quadrupole modes. Numerical studies show that this can be explained by parasitic RF losses on the adapter flange used to mount samples into the QPR. Coating several micrometer of niobium on those surfaces of the stainless steel flange that are exposed to the RF fields significantly reduced this bias, enabling a direct measurement of a residual resistance smaller than 5 n$Ω$ at 2 K and 413 MHz. A constant correction based on simulations was not feasible due to deviations from one measurement to another. However, this issue is resolved given these new results.

physics.acc-ph↗