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Research And Development For Electropolishing Of Nb For Ilc Accelerator Cavities
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Book Synopsis Research and Development for Electropolishing of Nb for ILC Accelerator Cavities by :
Download or read book Research and Development for Electropolishing of Nb for ILC Accelerator Cavities written by and published by . This book was released on 2009 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this project are to 1, Expand the scientific and technological understanding of the effect of post-treatment (electropolish, buffered chemical polish, low-temperature baking) on the surface of niobium; 2, Relate the knowledge to the performance of niobium superconducting radiofrequency accelerator cavities; and, 3, Thereby design and demonstrate an electropolish process that can be applied to complete cavities.
Book Synopsis Basic Electropolishing Process Research and Development in Support of Improved Reliable Performance SRF Cavities for the Future Accelerator by :
Download or read book Basic Electropolishing Process Research and Development in Support of Improved Reliable Performance SRF Cavities for the Future Accelerator written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Future accelerators require unprecedented cavity performance, which is strongly influenced by interior surface nanosmoothness. Electropolishing is the technique of choice to be developed for high-field superconducting radiofrequency cavities. Electrochemical impedance spectroscopy (EIS) and related techniques point to the electropolishing mechanism of Nb in a sulfuric and hydrofluoric acid electrolyte of controlled by a compact surface salt film under F- diffusion-limited mass transport control. These and other findings are currently guiding a systematic characterization to form the basis for cavity process optimization, such as flowrate, electrolyte composition and temperature. This integrated analysis is expected to provide optimum EP parameter sets for a controlled, reproducible and uniform surface leveling for Nb SRF cavities.
Book Synopsis Improvement of Cavity Performance by Electro-polishing in the 1.3GHz Nb Superconducting Cavities by : E. Kako
Download or read book Improvement of Cavity Performance by Electro-polishing in the 1.3GHz Nb Superconducting Cavities written by E. Kako and published by . This book was released on 1999 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Buffered Electropolishing - A New Way for Achieving Extremely Smooth Surface Finish on Nb SRF Cavities to be Used in Particle Accelerators by :
Download or read book Buffered Electropolishing - A New Way for Achieving Extremely Smooth Surface Finish on Nb SRF Cavities to be Used in Particle Accelerators written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Future accelerators require unprecedented cavity performance, which is strongly influenced by interior surface nano-smoothness. Electropolishing (EP) is the technique of choice to be developed for high-field superconducting radio frequency (SRF) cavities. Electrochemical impedance spectroscopy (EIS) and related techniques point to the electropolishing mechanism of Nb in a sulphuric and hydrofluoric acid electrolyte controlled by a compact surface salt film under F- diffusion-limited mass transport control. These and other findings are guiding a systematic characterization to form the basis for cavities process optimization.
Book Synopsis Advance in Vertical Buffered Electropolishing on Niobium for Particle Accelerators* by :
Download or read book Advance in Vertical Buffered Electropolishing on Niobium for Particle Accelerators* written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Niobium (Nb) is the most popular material that has been employed for making superconducting radio frequency (SRF) cavities to be used in various particle accelerators over the last couple of decades. One of the most important steps in fabricating Nb SRF cavities is the final chemical removal of 150 [mu]m of Nb from the inner surfaces of the SRF cavities. This is usually done by either buffered chemical polishing (BCP) or electropolishing (EP). Recently a new Nb surface treatment technique called buffered electropolishing (BEP) has been developed at Jefferson Lab. It has been demonstrated that BEP can produce the smoothest surface finish on Nb ever reported in the literature while realizing a Nb removal rate as high as 10 [mu]m/min that is more than 25 and 5 times quicker than those of EP and BCP(112) respectively. In this contribution, recent advance in optimizing and understanding BEP treatment technique is reviewed. Latest results from RF measurements on BEP treated Nb single cell cavities by our unique vertical polishing system will be reported.
Book Synopsis Hydrodynamic Thermal Modeling of 9-CELL Ilc Cavity Electropolishing and Implications for Improving the EP Process by :
Download or read book Hydrodynamic Thermal Modeling of 9-CELL Ilc Cavity Electropolishing and Implications for Improving the EP Process written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Recent Developments in Electropolishing and Tumbling R & D at Fermilab by :
Download or read book Recent Developments in Electropolishing and Tumbling R & D at Fermilab written by and published by . This book was released on 2009 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fermi National Accelerator Lab (Fermilab) is continuing to improve its infrastructure for research and development on the processing of superconducting radio frequency cavities. A single cell 3.9 GHz electropolishing tool built at Fermilab and operated at an industrial partner was recently commissioned. The EP tool was used to produce a single cell 3.9 GHz cavity that reached an accelerating gradient of 30 MV/m with a quality factor of 5 x 109. A single cell 1.3 GHz cavity was also electropolished at the same industrial vendor using the vendor's vertical full-immersion technique. On their first and only attempt the vendor produced a single cell 1.3 GHz cavity that reached 30 MV/m with a quality factor of 1 x 101°. These results will be detailed along with preliminary tumbling results.
Book Synopsis Improved Performance of JLab 7-Cell Cavities by Electropolishing by :
Download or read book Improved Performance of JLab 7-Cell Cavities by Electropolishing written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The great majority of experience in niobium SRF cavity processing at Jefferson Lab is with BCP etching. This has been used on CEBAF cavities and others totalling over 600 in number. With improved process quality control, field emission is now largely controlled and other factors limit performance. All of the prototype cavities developed for the 12 GeV upgrade, although meeting minimum requirements, have demonstrated a Q-drop in the 17?23 MV/m range that is not remedied by 120 C bake. Most of these cavities received>250 micron removal by BCP etch. Two of these cavities have been electropolished using the protocol under development within ILC R & D activities. The first such cavity was transformed from Q = 3×109 at 17 MV/m to quench from 1×1010 at 35 MV/m. The details of this and subsequent electropolished JLab 7-cell cavities will be reported.
Book Synopsis Development of Seamless Niobium Cavities for Accelerator Applications by :
Download or read book Development of Seamless Niobium Cavities for Accelerator Applications written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Superconducting niobium cavities for application in particle accelerators are usually fabricated by standard techniques such as forming of subcomponents by deep drawing and joining by electron beam welding. Even though these techniques are being used successfully in many larger-scale accelerator projects and improvements in accelerating gradients have been achieved over the last several years, there are often still problems with making defect-free electron beam welds. In addition, the manufacturing costs for such devices are significant and a drastic reduction in production costs is a necessary condition for future very large scale applications in, e.g., linear colliders. Seamless cavities made by spinning from a single sheet of material will dramatically reduce the fabrication costs and eliminate any problems associated with electron beam welding. The fabrication technique for seamless niobium cavities has been developed over the last few years at INFN LNL and several proto type single-cells of different material thickness and purity have been manufactured as well as a 5-cell cavity. Results from tests on these cavities after application of surface treatment techniques, such as buffered chemical polishing, ''barrel polishing'' and high temperature heat treatments, are discussed in this contribution. Q-values as high as 1011 and accelerating gradients up to E{_}acc (approximately) 30 MV/m have been measured.
Book Synopsis Fastest Electropolishing Technique on Niobium for Particle Accelerators by :
Download or read book Fastest Electropolishing Technique on Niobium for Particle Accelerators written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Field emission on the inner surfaces of niobium (Nb) superconducting radio frequency (SRF) cavities is still one of the major obstacles for reaching high accelerating gradients for SRF community. Our previous experimental results [1] seemed to imply that the threshold of field emission was related to the thickness of Nb surface oxide layers. In this contribution, a more detailed study on the influences of the surface oxide layers on the field emission on Nb surfaces will be reported. By anodization technique, the thickness of the surface pentoxide layer was artificially fabricated from 3nm up to 460nm. A home-made scanning field emission microscope (SFEM) was employed to perform the scans on the surfaces. Emitters were characterized using a scanning electron microscope together with an energy dispersive x-ray analyzer. The experimental results could be understood by a simple model calculation based on classic electromagnetic theory as shown in Ref. 1. Possibly implications for Nb SRF cavity applications from this study will be discussed.
Book Synopsis High Gradient Performance by Electropolishing with 1300 MHz Single and Multi-cell Niobium Superconducting Cavities by : K. Saito
Download or read book High Gradient Performance by Electropolishing with 1300 MHz Single and Multi-cell Niobium Superconducting Cavities written by K. Saito and published by . This book was released on 2000 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Surface Characterization of Nb Samples Electropolished Together with Real Superconducting Rf Accelerator Cavities by :
Download or read book Surface Characterization of Nb Samples Electropolished Together with Real Superconducting Rf Accelerator Cavities written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, we report the results of surface characterizations of niobium (Nb) samples electropolished together with a single cell superconducting radio-frequency accelerator cavity. These witness samples were located in three regions of the cavity, namely at the equator, the iris and the beam-pipe. Auger electron spectroscopy (AES) was utilized to probe the chemical composition of the topmost four atomic layers. Scanning electron microscopy with energy dispersive X-ray for elemental analysis (SEM/EDX) was used to observe the surface topography and chemical composition at the micrometer scale. A few atomic layers of sulfur (S) were found covering the samples non-uniformly. Niobium oxide granules with a sharp geometry were observed on every sample. Some Nb-O granules appeared to also contain sulfur.
Book Synopsis Development of Seamless Niobium Cavities for Accelerator Application by :
Download or read book Development of Seamless Niobium Cavities for Accelerator Application written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In a recent contribution to PAC '99, we reported about results from experiments with single-cell and one five-cell seamless cavities, which had undergone various surface treatments such as buffered chemical polishing, tumbling, grinding and high temperature heat treatments. Q-values as high as 1011 and accelerating gradients up to E{_}acc = (approximately) 30 MV/m had been measured. In the last several months we have carried out several more experiments on additional cavities made from seamless tubes and the results are discussed in this contribution. Also, one of the cavities mentioned in the PAC contribution was electropolished and was tested after only high pressure rinsing and in-situ baking. Results from these experiments are reported in this contribution.
Book Synopsis Study on Electro-Polishing Process by Niobium-Plate Sample With Artificial Pits by :
Download or read book Study on Electro-Polishing Process by Niobium-Plate Sample With Artificial Pits written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Electro-polishing (EP) process is the best candidate of final surface-treatment for the production of ILC cavities. Nevertheless, the development of defects on the inner-surface of the Superconducting RF cavity during EP process has not been studied by experimental method. We made artificial pits on the surface of a Nb-plate sample and observed the development of the pit-shapes after each step of 30um-EP process where 120um was removed by EP in total. This article describes the results of this EP-test of Nb-sample with artificial pits.
Book Synopsis Development of Seamless Niobium Cavities for Accelerator Applications by : Peter Kneisel
Download or read book Development of Seamless Niobium Cavities for Accelerator Applications written by Peter Kneisel and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Exploiting New Electrochemical Understanding of Niobium Electropolishing for Improved Performance of SRF Cavities for CEBAF. by :
Download or read book Exploiting New Electrochemical Understanding of Niobium Electropolishing for Improved Performance of SRF Cavities for CEBAF. written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent incorporation of analytic electrochemistry into the development of protocols for electropolishing niobium SRF cavities has yielded new insights for optimizing this process for consistent, high-performance results. Use of reference electrodes in the electrolyte, electrochemical impedance spectroscopy (EIS), rotating disk electrodes (RDE), and controlled sample temperatures has greatly clarified the process dynamics over the empirical understanding developed via years of practice. Minimizing RF losses at high operational gradients is very valuable for CW linacs. Jefferson Lab is applying these new insights to the low-loss 7-cell cavity design developed for the CEBAF 12 GeV Upgrade. Together with controlled cleaning and assembly techniques to guard against field-emission-causing particulates, the resulting process is yielding consistent cavity performance that exceeds project requirements. Cavity tests show BCS-limited Q well above 30 MV/m. Detailed process data, interpretation, and resulting rf performance data will be presented.
Book Synopsis Development of Seamless Niobium Cavities for Accelerator Application by : Peter Kneisel
Download or read book Development of Seamless Niobium Cavities for Accelerator Application written by Peter Kneisel and published by . This book was released on 2000 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
