Download or read book Single Crystal and Large Grain Niobium Research at Michigan State University written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As Superconducting Radio Frequency (SRF) technology is used in more accelerator designs, research has focused on increasing the efficiency of these accelerators by pushing gradients and investigating cast reduction options. Today, most SRF structures are fabricated from high purity niobium. Over years of research, a material specification has been derived that defines a uniaxial, fine gain structure for SRF cavity fabrication. Most recently a push has been made to investigate the merits of using single or large grain niobium as a possible alternative to fine grain niobium. Michigan State University (MSU), in collaboration with Fermi National Accelerator Laboratory (FNAL) and Thomas Jefferson National Accelerator Facility (JLAB), is researching large grain niobium via cavity fabrication processes end testing, as well as exploring materials science issues associated with recrystallization and heat transfer. Single-cell 1.3 GHz (Beta=0.081) cavities made from both fine end large grain niobium were compared both in terms of fabrication procedures and performance. Two 7-cell cavities are currently being fabricated.
Download or read book Investigation of Active Slip Systems in High Purity Single Crystal Niobium written by Derek Baars and published by . This book was released on 2013 with total page 321 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Single Crystal Large Grain Niobium Technology written by Ganapati Rao Myneni and published by AIP Conference Proceedings / H. This book was released on 2007-08-30 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: SRF Technology based accelerators, FEL’s, and ERL’s, are becoming common worldwide. Several new frontier technologies and applications are expected to be evolving in coming years as the cost of SRF technology comes. Terra Hertz (THz) Science could benefit from these advances, and many applications are likely to be developed in the fields of medical imaging, material science, pharmaceuticals, communications etc.
Download or read book Proceedings of the 2nd World Congress on Integrated Computational Materials Engineering ICME written by Mei Li and published by Springer. This book was released on 2016-12-19 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book represents a collection of papers presented at the 2nd World Congress on Integrated Computational Materials Engineering (ICME), a specialty conference organized by The Minerals, Metals & Materials Society (TMS).
Download or read book Development of Large Grain Single Crystal Niobium Cavity Technology at Jefferson Lab written by Peter Kneisel and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Approximately two years ago we started to develop high performance niobium accelerating cavities based on large grain or single crystal high purity niobium. We have fabricated and tested 15 single cell cavities of various shapes and frequencies between 1300 MHz and 2300 MHz using material from a total of 9 different very large grain niobium ingots from four niobium suppliers. The materials differed not only in grain sizes, but also in RRR? value and in the amount of Ta contained in the material. In one ingot supplied by CBMM the central grain exceeded 7 inches in diameter and this was used to fabricate two 2.2 GHz cavities. A single crystal 1300 MHz mono-cell cavity was also produced at DESY by rolling out a single crystal to the size required for this cavity. It was sent to Jlab for surface treatment and testing. In addition, we have fabricated three 7-cell cavities: two of the Jlab high gradient (HG) shape and one of the ILC Low Loss shape. Two 9-cell TESLA shape cavities are presently in fabrication at Jlab and are close to completion.
Download or read book Superconducting Radiofrequency Technology for Accelerators written by Hasan Padamsee and published by John Wiley & Sons. This book was released on 2023-03-06 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: Superconducting Radiofrequency Technology for Accelerators Single source reference enabling readers to understand and master state-of-the-art accelerator technology Superconducting Radiofrequency Technology for Accelerators provides a quick yet thorough overview of the key technologies for current and future accelerators, including those projected to enable breakthrough developments in materials science, nuclear and astrophysics, high energy physics, neutrino research and quantum computing. The work is divided into three sections. The first part provides a review of RF superconductivity basics, the second covers new techniques such as nitrogen doping, nitrogen infusion, oxide-free niobium, new surface treatments, and magnetic flux expulsion, high field Q slope, complemented by discussions of the physics of the improvements stemming from diagnostic techniques and surface analysis as well as from theory. The third part reviews the on-going applications of RF superconductivity in already operational facilities and those under construction such as light sources, proton accelerators, neutron and neutrino sources, ion accelerators, and crab cavity facilities. The third part discusses planned accelerator projects such as the International Linear Collider, the Future Circular Collider, the Chinese Electron Positron Collider, and the Proton Improvement Plan-III facility at Fermilab as well as exciting new developments in quantum computing using superconducting niobium cavities. Written by the leading expert in the field of radiofrequency superconductivity, Superconducting Radiofrequency Technology for Accelerators covers other sample topics such as: Fabrication and processing on Nb-based SRF structures, covering cavity fabrication, preparation, and a decade of progress in the field SRF physics, covering zero DC resistance, the Meissner effect, surface resistance and surface impedance in RF fields, and non-local response of supercurrent N-doping and residual resistance, covering trapped DC flux losses, hydride losses, and tunneling measurements Theories for anti-Q-slope, covering the Xiao theory, the Gurevich theory, non-equilibrium superconductivity, and two fluid model based on weak defects Superconducting Radiofrequency Technology for Accelerators is an essential reference for high energy physicists, power engineers, and electrical engineers who want to understand the latest developments of accelerator technology and be able to harness it to further research interest and practical applications.
Download or read book Single Crystal large Grain Niobium Technology written by and published by . This book was released on 2007 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Government Research Reports written by and published by . This book was released on 1963 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Navy Research Task Summary 1961 written by United States. Office of Naval Research and published by . This book was released on 1962 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Abstract Bulletin written by Defense Documentation Center (U.S.) and published by . This book was released on 1961-07 with total page 1766 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Microscopic Defects on Superconducting Properties of High Purity Niobium Used for SRF Cavities written by Mingmin Wang and published by . This book was released on 2020 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: High purity niobium has been used to fabricate superconducting radio-frequency (SRF) cavities for linear particle accelerator applications for decades due to its high critical temperature (9.3 K) and critical magnetic field. Great progress has been made in achieving high accelerating gradients and quality factors (a measure of efficiency). However, the performance of Nb cavities still suffers from the variability of the material such that high quality factors and accelerating gradients cannot be consistently produced.Trapped magnetic flux is well known for causing significant radio-frequency losses. Both local flux penetration and flux trapping indicate the local suppression of superconductivity. Magnetic flux from both unshielded earth field and thermoelectric currents can be trapped when a cavity is cooled through its superconducting transition temperature. Microstructural defects including hydrogen, grain boundaries, and dislocations are possible causes for flux trapping. However, the details of magnetic flux trapping mechanisms and conditions that enable it are still not clear. Research on this topic has been very active in the SRF community. Cavity studies on flux expulsion after different heat treatments and cooldown procedures have been performed in recent years, but the study of flux trapping mechanisms at the microscopic level is still lacking.In order to study the effect of microscopic defects on flux trapping, single crystal and bicrystal samples were designed with strategically chosen tensile axes to intentionally introduce defects by a 5% tensile strain. Magneto-Optical (MO) Imaging was used to visualize locations where magnetic flux was trapped, and the dislocation substructures were studied using Electron Channeling Contrast Imaging (ECCI).The results show that high angle grain boundaries (HAGB) and low angle grain boundaries (LAGBs) have different flux penetration behaviors. LAGBS could be hydrogen segregation sites leading to precipitation of normal conducting hydrides along LAGBs at ~100-130 K during cooling. In hydrogen contaminated single-crystal samples, large hydride scars (locations where a hydride formed and then dissolved during heating) were observed both at the LAGBs and within the grain after MO cooling; however, only hydrides at the LAGBs appeared to cause premature flux penetration. Flux trapping related to LAGBs could still be observed after the heat treatment removed most of the hydrogen. By contrast, the flux penetration along a HAGB could be turned off by heat treatment that removed hydrogen and restored by reintroducing hydrogen into the sample. This work suggests that HAGBs are not as effective at causing flux penetration or trapping as hydrides and LAGBs.Some deformed bi-crystal samples show correlations between a larger amount of deformation or a higher density of dislocations and more trapped flux. Deformation led to the development of dislocation substructures; however, the effect of dislocation arrangements on flux penetration could not be observed in the current work. Further study with flux measurement techniques of a higher resolution and sensitivity is necessary to understand what kinds of dislocation substructures are most likely to cause flux penetration.
Download or read book Navy Research Task Summary written by United States. Office of Naval Research and published by . This book was released on with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1974 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preliminary Results from Single Crystal and Very Large Crystal Niobium Cavities written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have fabricated and tested several single cell cavities using material from very large grain niobium ingots. In one case the central grain exceeded 7 inches in diameter and this was used to fabricate two 2.2 GHz cavities. This activity had a dual purpose: to investigate the influence of grain boundaries on the often observed Q-drop at gradients E[sub acc]> 20 MV/m in the absence of field emission, and to study the possibility of using ingot material for cavity fabrication without going through the expensive rolling process. The sheets for these cavities were cut from the ingot by wire electro-discharge machining (EDM) and subsequently formed into half-cells by deep drawing. The following fabrication steps were standard: machining of weld recesses, electron beam welding of beam pipes onto the half cells and final equator weld to join both half cell/beam pipe subunits. The cavities showed heavy Q-disease caused by the EDM. After hydrogen degassing at 800 C for 3 hrs in UHV and about 200 [micro]m total removals from the inner surface by BCP 1:1:1, the cavities showed promising results, however, the Q-drop was still present. In the two cavities made from large grain material accelerating gradients of 30 MV/m have been reached. After ''in-situ'' baking the Q-drop disappeared. The smaller cavities made from single crystal material showed very low residual resistances and accelerating gradients up to E[sub acc] = 45 MV/m were reached (one of the highest ever achieved), corresponding to a peak surface magnetic fields (B[sub p]) of 160 mT. In one rf test at 2 K, a B[sub p] = 185 mT was reached for few hundred milliseconds, close to the theoretical critical field of this material.
Download or read book Grants and Awards for the Fiscal Year Ended written by National Science Foundation (U.S.) and published by . This book was released on with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Government Research Development Reports written by and published by . This book was released on 1969 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1992 with total page 1192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
