Related papers: Cryogenic rf test of the first plasma etched SRF c…
The performance of superconducting radio-frequency (SRF) cavities depends on the niobium surface condition. Recently, various heat-treatment methods have been investigated to achieve unprecedented high quality factor (Q) and high…
With the aid of COMSOL multiphysics simulations, a compact microwave plasma reactor operated at 2.45 GHz frequency has been designed for diamond film deposition. The reactor consists of a cylindrical cavity that resonates in the fundamental…
Muon collider is a considerable candidate of the next-generation high-energy lepton collider machine. Operating an RF cavity in a multi-Tesla magnet is a critical requirement in a muon accelerator and a cooling channel. However, the maximum…
Superconducting radio-frequency (SRF) accelerating cavities are a promising technology for compact, high-power, MeV-scale accelerators, providing continuous beam operation for a wide range of potential applications in industry, medicine,…
Low-pressure multi-frequency capacitively coupled plasmas are used for numerous etch and deposition applications in the semiconductor industry. Pulsing of the radio-frequency (RF) sources enables control of neutral and charged species in…
The ZaP-HD sheared-flow-stabilized (SFS) Z-pinch device is a testbed for experimental investigation of plasma-electrode interactions. The graphite electrode is exposed to a high temperature, high density Z-pinch plasma while supplying large…
To achieve Ampere-class electron beam accelerators the pulse delivery rate need to be much higher than the typical photo injector repetition rate of the order of a few kilohertz. We propose here an injector which can, in principle, generate…
To assess the feasibility of in-situ plasma cleaning for copper cavities, a 13.56 MHz inductively coupled plasma platform with a built-in coil was developed at Tsinghua University. Experiments were conducted using this platform to optimize…
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…
Spectrometers based on high-finesse optical cavities have proven to be powerful tools for applied and fundamental studies. Extending this technology to the deep cryogenic regime is beneficial in many ways: Doppler broadening is reduced,…
SRF cavities for particle acceleration are conventionally operated immersed in a bath of liquid helium at 4.2 K and below. Although this cooling configuration is practically and economically viable for large scientific accelerator…
Historically, many advances in superconducting radio frequency (SRF) cavities destined for use in advanced particle accelerators have come empirically, through the iterative procedure of modifying processing and then performance testing.…
A straightforward way to determine the electric field gradient $-$ principal axes frame (EFG-PAF) on single crystal samples with spin 3/2 nuclei is demonstrated. Nuclear quadrupole resonance (NQR) spectroscopy is used to determine the Rabi…
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…
This paper provides a unique and to the best of our knowledge first-of-a-kind attempt to develop chemical processes that may contribute to the volume reduction of SMR TRISO-based fuels and aims at the eventual ability to reprocess the spent…
Radio-frequency (RF) driven helicon plasma sources can produce relatively high-density plasmas (n > 10^19 m-3) at relatively moderate powers (< 2 kW) in argon. However, to produce similar high-density plasmas for fusion relevant gases such…
Nb3Sn (Tc ~ 18 K and Hsh ~ 400 mT) is a prospective material to replace Nb (Tc ~ 9 K and Hsh ~ 200 mT) in SRF accelerator cavities for significant cost reduction and performance enhancement. Because of its material properties, Nb3Sn is best…
The recent achievements in the performance of superconducting RF (SRF) photoinjectors have opened a new era in the development of the reliable high-brightness CW electron sources. While the SRF guns become one of the most promising…
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…
Due to the complicated environment of the plasma sheath, it is difficult to experimentally measure plasma characteristics in the narrow geometry where sheaths from opposite boundaries overlap. Since such geometries are often found in…