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Laser Nitriding For Niobium Superconducting Radio Frequency Accelerator Cavities
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Book Synopsis Laser Nitriding for Niobium Superconducting Radio-frequency Accelerator Cavities by :
Download or read book Laser Nitriding for Niobium Superconducting Radio-frequency 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: Particle accelerators are a key tool for scientific research ranging from fundamental studies of matter to analytical studies at light sources. Cost-forperformance is critical, both in terms of initial capital outlay and ongoing operating expense, especially for electricity. It depends on the niobium superconducting radiofrequency (SRF) accelerator cavities at the heart of most of these machines. Presently Nb SRF cavities operate near 1.9 K, well (and expensively) below the 4.2 K atmospheric boiling point of liquid He. Transforming the 40 nm thick active interior surface layer from Nb to delta NbN (Tc = 17 K instead of 9.2 K) appears to be a promising approach. Traditional furnace nitriding appears to have not been successful for this. Further, exposing a complete SRF cavity to the time-temperature history required for nitriding risks mechanical distortion. Gas laser nitriding instead has been applied successfully to other metals [P. Schaaf, Prog. Mat. Sci. 47 (2002) 1]. The beam dimensions and thermal diffusion length permit modeling in one dimension to predict the time course of the surface temperature for a range of per-pulse energy densities. As with the earlier work, we chose conditions just sufficient for boiling as a reference point. We used a Spectra Physics HIPPO nanosecond laser (l = 1064 nm, Emax= 0.392 mJ, beam spot@ 34 microns, PRF =15 - 30 kHz) to obtain an incident fluence of 1.73 - 2.15 J/cm2 for each laser pulse at the target. The target was a 50 mm diameter SRF-grade Nb disk maintained in a nitrogen atmosphere at a pressure of 550 - 625 torr and rotated at a constant speed of 9 rpm. The materials were examined by scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and x-ray diffraction (XRD). The SEM images show a sharp transition with fluence from a smooth, undulating topography to significant roughening, interpreted here as the onset of ablation. EPMA measurements of N/Nb atom ratio as a function of depth found a constant value to depths greater than the SRF active layer thickness. Certain irradiation conditions resulted in values consistent with formation of delta NbN. Under certain irradiation conditions, XRD data were consistent only with delta NbN on top of Nb metal. Funding: authored by Jefferson Science Associates LLC under US DOE Contract De-AC05-06OR23177. We are indebted to Prof. P. Schaaf (Goettingen) for the simulation code and helpful discussions.
Book Synopsis Surface Polishing of Niobium for Superconducting Radio Frequency (SRF) Cavity Application by : Liang Zhao (Ph. D.)
Download or read book Surface Polishing of Niobium for Superconducting Radio Frequency (SRF) Cavity Application written by Liang Zhao (Ph. D.) and published by . This book was released on 2015 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Laser Surface Engineering by : Jonathan R. Lawrence
Download or read book Laser Surface Engineering written by Jonathan R. Lawrence and published by Elsevier. This book was released on 2014-10-02 with total page 719 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lasers can alter the surface composition and properties of materials in a highly controllable way, which makes them efficient and cost-effective tools for surface engineering. This book provides an overview of the different techniques, the laser-material interactions and the advantages and disadvantages for different applications. Part one looks at laser heat treatment, part two covers laser additive manufacturing such as laser-enhanced electroplating, and part three discusses laser micromachining, structuring and surface modification. Chemical and biological applications of laser surface engineering are explored in part four, including ways to improve the surface corrosion properties of metals. Provides an overview of thermal surface treatments using lasers, including the treatment of steels, light metal alloys, polycrystalline silicon and technical ceramics Addresses the development of new metallic materials, innovations in laser cladding and direct metal deposition, and the fabrication of tuneable micro- and nano-scale surface structures Chapters also cover laser structuring, surface modification, and the chemical and biological applications of laser surface engineering
Book Synopsis Surface Characterization of Impurities in Superconducting Niobium for Radio Frequency (RF) Cavities Used in Particle Accelerators by : Prateek Maheshwari
Download or read book Surface Characterization of Impurities in Superconducting Niobium for Radio Frequency (RF) Cavities Used in Particle Accelerators written by Prateek Maheshwari and published by . This book was released on 2012 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Surface Polishing of Niobium for Superconducting Radio Frequency (SRF) Cavity Applications by :
Download or read book Surface Polishing of Niobium for Superconducting Radio Frequency (SRF) Cavity Applications written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Niobium cavities are important components in modern particle accelerators based on superconducting radio frequency (SRF) technology. The interior of SRF cavities are cleaned and polished in order to produce high accelerating field and low power dissipation on the cavity wall. Current polishing methods, buffered chemical polishing (BCP) and electro-polishing (EP), have their advantages and limitations. We seek to improve current methods and explore laser polishing (LP) as a greener alternative of chemical methods. The topography and removal rate of BCP at different conditions (duration, temperature, sample orientation, flow rate) was studied with optical microscopy, scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). Differential etching on different crystal orientations is the main contributor to fine grain niobium BCP topography, with gas evolution playing a secondary role. The surface of single crystal and bi-crystal niobium is smooth even after heavy BCP. The topography of fine grain niobium depends on total removal. The removal rate increases with temperature and surface acid flow rate within the rage of 0~20 °C, with chemical reaction being the possible dominate rate control mechanism. Surface flow helps to regulate temperature and avoid gas accumulation on the surface. The effect of surface flow rate on niobium EP was studied with optical microscopy, atomic force microscopy (AFM), and power spectral density (PSD) analysis. Within the range of 0~3.7 cm/s, no significant difference was found on the removal rate and the macro roughness. Possible improvement on the micro roughness with increased surface flow rate was observed. The effect of fluence and pulse accumulation on niobium topography during LP was studied with optical microscopy, SEM, AFM, and PSD analysis. Polishing on micro scale was achieved within fluence range of 0.57~0.90 J/cm2, with pulse accumulation adjusted accordingly. Larger area treatment was proved possible by overlapping laser tracks at proper ratio. Comparison of topography and PSD indicates that LP smooths the surface in a way similar to EP. The optimized LP parameters were applied to different types of niobium surfaces representing different stages in cavity fabrication. LP reduces the sharpness on rough surfaces effectively, while doing no harm to smooth surfaces. Secondary ion mass spectrometer (SIMS) analysis showed that LP reduces the oxide layer slightly and no contamination occurred from LP. EBSD showed no significant change on crystal structure after LP.
Book Synopsis Surface Study of Niobium for Superconducting Radio Frequency (SRF) Accelerators by : Hui Tian
Download or read book Surface Study of Niobium for Superconducting Radio Frequency (SRF) Accelerators written by Hui Tian and published by . This book was released on 2008 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Heat Treatment by : Frank Czerwinski
Download or read book Heat Treatment written by Frank Czerwinski and published by BoD – Books on Demand. This book was released on 2012-09-26 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heat treatment and surface engineering are seen as crucial elements in the design and manufacture of strategic components in a wide range of market sectors and industries including air, sea and land transportation, energy production, mining, defense or agriculture. This book offers a broad review of recent global developments in an application of thermal and thermochemical processing to modify the microstructure and properties of a wide range of engineering materials. Although there is no formal partition of the book, chapters represent two different application areas of heat treatment. The first group covers the conventional heat treatment with processing of bearing rings, wrought and cast steels, aluminum alloys, fundamentals of thermochemical treatment, details of carbonitriding and a design of cooling units. The second group describes a use of non-conventional thermal routes during manufacturing cycles of such materials as vanadium carbides, titanium dioxide, metallic glasses, superconducting ceramics, nanoparticles, metal oxides, battery materials and slag mortars. A mixture of conventional and novel applications, exploring a variety of processes employing heating, quenching and thermal diffusion, makes the book very useful for a broad audience of scientists and engineers from academia and industry.
Book Synopsis Surface Studies of Acid-treated Niobium for Superconducting Radio Frequency Cavities by : David R. Smith
Download or read book Surface Studies of Acid-treated Niobium for Superconducting Radio Frequency Cavities written by David R. Smith and published by . This book was released on 2004 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Niobium Near Surface Composition Relevant for Superconducting Radio-frequency Cavities by : Guilherme Dalla Lana Semione
Download or read book Niobium Near Surface Composition Relevant for Superconducting Radio-frequency Cavities written by Guilherme Dalla Lana Semione and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Thermodynamic Evaluation of the Propensity of Niobium to Absorb Hydrogen During Fabrication of Superconducting Radio Frequency Accelerator Cavities by : Richard E. Ricker
Download or read book Thermodynamic Evaluation of the Propensity of Niobium to Absorb Hydrogen During Fabrication of Superconducting Radio Frequency Accelerator Cavities written by Richard E. Ricker and published by . This book was released on 2009 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Springback in Deep Drawn High Purity Niobium for Superconductor Cavities by : Ganapati Rao Myneni
Download or read book Springback in Deep Drawn High Purity Niobium for Superconductor Cavities written by Ganapati Rao Myneni and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Superconducting radio frequency (SRF) cavities made from deep drawn high-purity niobium have become a popular approach for the design of particle accelerators. A number of current accelerators use this technology and it is a leading candidate for future designs. The development of this technology has required significant advances in many scientific fields including metallurgy, high vacuum physics, surface science, and forming. Recently proposed modifications to the current process for fabrication of these cavities has resulted in increased concern about the distribution of deformation, residual stress patterns, and springback. This presentation will report on the findings of a recently initiated program to study plastic flow and springback in the fabrication of these cavities and the influence of metallurgical variables including grain size and impurity content.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1988 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Observation of Stable Low Surface Resistance in Large-Grain Niobium SRF Cavities by :
Download or read book Observation of Stable Low Surface Resistance in Large-Grain Niobium SRF Cavities written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Low surface resistance, or high unloaded quality factor (Q0), superconducting radio frequency (SRF) cavities are being pursued actively nowadays as their application in large-scale CW SRF accelerators can save capital and operational cost in cryogenics. There are different options in realization of such cavities. One of them is the large-grain (LG) niobium cavity. In this contribution, we present new experimental results in evaluation of LG niobium cavities cooled down in the presence of an external magnetic field. High Q0 values are achieved even with an ambient magnetic field of up to 100 mG. More over, it is observed that these high Q0 values are super-robust against repeated quench, literally not affected at all after the cavity being deliberately quenched for hundreds of times in the presence of an ambient magnetic field of up to 200 mG.
Book Synopsis Temperature Mapping of Nitrogen-doped Niobium Superconducting Radiofrequency Cavities by :
Download or read book Temperature Mapping of Nitrogen-doped Niobium Superconducting Radiofrequency Cavities written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It was recently shown that diffusing nitrogen on the inner surface of superconducting radiofrequency (SRF) cavities at high temperature can improve the quality factor of the niobium cavity. However, a reduction of the quench field is also typically found. To better understand the location of rf losses and quench, we used a thermometry system to map the temperature of the outer surface of ingot Nb cavities after nitrogen doping and electropolishing. Surface temperature of the cavities was recorded while increasing the rf power and also during the quenching. The results of thermal mapping showed no precursor heating on the cavities and quenching to be ignited near the equator where the surface magnetic field is maximum. Hot-spots at the equator area during multipacting were also detected by thermal mapping.
Book Synopsis Laser Polishing for Topography Management of Accelerator Cavity Surfaces by :
Download or read book Laser Polishing for Topography Management of Accelerator Cavity Surfaces written by and published by . This book was released on 2015 with total page 675 pages. Available in PDF, EPUB and Kindle. Book excerpt: Improved energy efficiency and reduced cost are greatly desired for advanced particle accelerators. Progress toward both can be made by atomically-smoothing the interior surface of the niobium superconducting radiofrequency accelerator cavities at the machine's heart. Laser polishing offers a green alternative to the present aggressive chemical processes. We found parameters suitable for polishing niobium in all surface states expected for cavity production. Careful measurement of the resulting surface chemistry revealed a modest thinning of the surface oxide layer, but no contamination.
Book Synopsis The Periodic Table: Nature's Building Blocks by : J. Theo Kloprogge
Download or read book The Periodic Table: Nature's Building Blocks written by J. Theo Kloprogge and published by Elsevier. This book was released on 2020-11-18 with total page 931 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Periodic Table: Nature’s Building Blocks: An Introduction to the Naturally Occurring Elements, Their Origins and Their Uses addresses how minerals and their elements are used, where the elements come from in nature, and their applications in modern society. The book is structured in a logical way using the periodic table as its outline. It begins with an introduction of the history of the periodic table and a short introduction to mineralogy. Element sections contain their history, how they were discovered, and a description of the minerals that contain the element. Sections conclude with our current use of each element. Abundant color photos of some of the most characteristic minerals containing the element accompany the discussion. Ideal for students and researchers working in inorganic chemistry, minerology and geology, this book provides the foundational knowledge needed for successful study and work in this exciting area. Describes the link between geology, minerals and chemistry to show how chemistry relies on elements from nature Emphasizes the connection between geology, mineralogy and daily life, showing how minerals contribute to the things we use and in our modern economy Contains abundant color photos of each mineral that bring the periodic table to life
