Download or read book High Gradient Superconducting Niobium Cavities written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Superconducting niobium cavities used in particle accelerators are limited in their rf performance by two phenomena: quench field levels below the theoretical limit of the material caused by defects, and field emission loading resulting from artificial contamination of the superconducting surfaces during surface treatment and assembly procedures. In recent years, the community involved in SRF technology developments has successfully improved cavity performances by applying advanced surface treatment methods such as chemical polishing, electropolishing, tumbling, high temperature heat treatment, high pressure rinsing, ''in situ'' high peak power processing, and clean room assembly procedures. In addition, improvements in the material properties such as thermal conductivity by ''solid state'' gettering'' and very strict QA methods, both in material inspection and during cavity fabrication, have resulted in cavity performance levels of E{sub acc} up to 40 MV/m in monocells and gradients in the vicinity of 30 MV/m in multicell structures at Q-values of (almost equal to) 101° at a temperature of 2K. More recently the fabrication of ''seamless'' cavities by spinning is being pursued with encouraging results. This process eliminates electron beam welds, which sometimes are the causes of performance degradations.

Download or read book High Gradient Superconducting Niobium Cavities written by Peter Kneisel and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High gradient Pulsed Operation of Superconducting Niobium Cavities written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Tests performed on several Niobium TM010 cavities at frequencies of about 2856 MHz using a high-power, pulsed method indicate that, at the end of the charging pulse, peak surface magnetic fields of up to approx. 1300 Oe, corresponding to a peak surface electric field of approx. 68 MV/m, can be reached at 4.2°K without appreciable average losses. Further studies of the properties of superconductors under pulsed operation might shed light on fundamental properties of rf superconductivity, as well as lead to the possibility of applying the pulse method to the operation of high-gradient linear colliders. 7 references, 30 figures, 2 tables.

Download or read book Development of High Gradient L Band Superconducting Cavities written by and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Since 1990, the development of L-band superconducting niobium cavities for high gradient applications has been pursued at KEK. In the latest tests of 1.3 GHz single-cell cavities, the maximum accelerating gradients of more than 20 MV/m were attained with Q0 values of -2 x 101° at 1.9K. This paper reports results of measurements on several single-cell cavities and the fabrication of the first 9-cell structure.

Download or read book Superconducting Niobium Cavities with High Gradients August 1992 written by Peter Kneisel and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ultra high Quality Factors in Superconducting Niobium Cavities in Ambient Magnetic Fields Up to 190 MG written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ambient magnetic field, if trapped in the penetration depth, leads to the residual resistance and therefore sets the limit for the achievable quality factors in superconducting niobium resonators for particle accelerators. Here, we show that a complete expulsion of the magnetic flux can be performed and leads to: (1) record quality factors Q> 2 x 1011 up to accelerating gradient of 22 MV/m; (2) Q ~ 3 x 1010 at 2 K and 16 MV/m in up to 190 mG magnetic fields. This is achieved by large thermal gradients at the normal/superconducting phase front during the cooldown. Our findings open up a way to ultra-high quality factors at low temperatures and show an alternative to the sophisticated magnetic shielding implemented in modern superconducting accelerators.

Download or read book Ultimate Gradient Limitation in Niobium Superconducting Accelerating Cavities written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The present study is addressed to the theoretical description of the ultimate gradient limitation in SRF cavities. Our intent is to exploit experimental data to confirm models which provide feed-backs on how to improve the current state-of-art. New theoretical insight on the cavities limiting factor can be suitable to improve the quench field of N-doped cavities, and therefore to take advantage of high Q0 at high gradients.

Download or read book New Results of Development on High Efficiency High Gradient Superconducting Rf Cavities written by and published by . This book was released on 2015 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on the latest results of development on high-efficiency high-gradient superconducting radio frequency (SRF) cavities. Several 1-cell cavities made of large-grain niobium (Nb) were built, processed and tested. Two of these cavities are of the Low Surface Field (LSF) shape. Series of tests were carried out following controlled thermal cycling. Experiments toward zero-field cooling were carried out. The best experimentally achieved results are Eacc = 41 MV/m at Q0 = 6.5×1010 at 1.4 K by a 1-cell 1.3 GHz large-grain Nb TTF shape cavity and Eacc = 49 MV/m at Q0 = 1.5×1010 at 1.8 K by a 1-cell 1.5 GHz large-grain Nb CEBAF upgrade low-loss shape cavity.

Download or read book Analyzing Opera Verdi and Wagner written by and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of Ultra High Gradient and High Q sub 0 Superconducting Radio Frequency Cavities written by and published by . This book was released on 2013 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on the recent progress at Jefferson Lab in developing ultra high gradient and high Q0 superconducting radio frequency (SRF) cavities for future SRF based machines. A new 1300 MHz 9-cell prototype cavity is being fabricated. This cavity has an optimized shape in terms of the ratio of the peak surface field (both magnetic and electric) to the acceleration gradient, hence the name low surface field (LSF) shape. The goal of the effort is to demonstrate an acceleration gradient of 50 MV/m with Q0 of 101° at 2 K in a 9-cell SRF cavity. Fine-grain niobium material is used. Conventional forming, machining and electron beam welding method are used for cavity fabrication. New techniques are adopted to ensure repeatable, accurate and inexpensive fabrication of components and the full assembly. The completed cavity is to be first mechanically polished to a mirror-finish, a newly acquired in-house capability at JLab, followed by the proven ILC-style processing recipe established already at JLab. In parallel, new single-cell cavities made from large-grain niobium material are made to further advance the cavity treatment and processing procedures, aiming for the demonstration of an acceleration gradient of 50 MV/m with Q0 of 2-101° at 2K.

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:

Download or read book Superconducting Technology written by Kristian Fossheim and published by World Scientific. This book was released on 1991 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains an interdisciplinary selection of timely articles which cover a wide range of superconducting technologies ranging from high tech medicine (10-12 Gauss) to multipurpose sensors, microwaves, radio engineering, magnet technology for accelerators, magnetic energy storage, and power transmission on the 109 watt scale. It is aimed primarily at the non-specialist and will be suitable as an introductory course book for those in the relevant fields and related industries. As shown in the title several examples of high-c applications are included. While low-Tc is still the leading technology, for instance, in cables and SQUIDS, case studies in these areas are presented.

Download or read book RF Superconductivity for Accelerators written by Hasan Padamsee and published by John Wiley & Sons. This book was released on 2008-02-26 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces some of the key ideas of this exciting field, using a pedagogic approach, and presents a comprehensive overview of the field. It is divided into four parts. The first part introduces the basic concepts of microwave cavities for particle acceleration. The second part is devoted to the observed behavior of superconducting cavities. In the third part,general issues connected with beam-cavity interaction and the related issues for the critical components are covered. The final part discusses applications of superconducting cavities to frontier accelerators of the future, drawing heavily on the examples that are in their most advanced stage. Each part of the book ends in a Problems section to illustrate and amplify text material as well as draw on example applications of superconducting cavities to existing and future accelerators.

Download or read book High Field Studies on L band Superconducting Cavities at KEK written by and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Several 1.3 GHz single-cell and nine-cell niobium cavities were fabricated to attain a higher maximum accelerating gradient and to understand the phenomena limiting it. Vertical cold tests at (almost equal to)1.8 K for the 4 single-cell cavities prepared by various surface treatments have been conducted 15 times. In eight of the tests, maximum accelerating gradients (E{sub acc}, max) of more than 14 MV/m were obtained with no field emission. Furthermore, E{sub acc}, max values of higher than 20 MV/m with a high Q0 value of (almost equal to)101° were achieved repeatedly after heat treatment at 1400 degrees C. Once quenching was observed at E{sub acc}, max (14 (almost equal to) 20 MV/m), however, a common phenomenon resulting in Q0-deterioration occurred in every test. The cavity performances and the phenomenon at high fields are reported in this paper.

Download or read book RF Superconductivity written by Hasan Padamsee and published by John Wiley & Sons. This book was released on 2009-03-30 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the second book to RF Superconducting, written by one of the leading experts. The book provides fast and up-to-date access to the latest advances in the key technology for future accelerators. Experts as well as newcomers to the field will benefit from the discussion of progress in the basic science, technology as well as recent and forthcoming applications. Researchers in accelerator physics will also find much that is relevant to their discipline.

Download or read book Superconducting Cavities from High Thermal Conductivity Niobium for CEBAF written by and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Continuous Electron Beam Accelerator Facility (CEBAF) is presently under construction in Newport News, VA. The accelerator consists of approximately 169 meters of 5-cell niobium cavities made from high thermal conductivity niobium with RRR values> 250. Cavities have been manufactured of material from three different suppliers. The material properties like thermal conductivity, residual resistivity and tensile behavior are compared. Results on the performance of these cavities in the presence of high rf fields are reported. Q(sub)0 values as high as 10^10 at 2 K and accelerating gradient of E> 14 MV/m have been achieved.

Download or read book Experimental Results in Superconducting Niobium Resonators for High brightness Ion Beam Acceleration written by and published by . This book was released on 1990 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two niobium resonant cavities for high-brightness ion beam acceleration have been constructed and tested. The first was based on a coaxial quarter-wave geometry and was optimized for phase velocity?0 = 0.15. This cavity, which resonates at 400 MHz in the fundamental mode, operated at an average (wall-to-wall) accelerating gradient of 12.9 MV/m under continuous-wave (cw) fields. At his gradient, a cavity Q of 1.4 × 108 was measured. The second was based on a coaxial half-wave geometry and was optimized for?0 = 0.12. This cavity, which resonates at 355 MHz in the fundamental mode, operated at an average accelerating gradient of 18.0 MV/m under cw fields. This is the highest average accelerating gradient achieved to date in low-velocity structures designed for cw operation. At this gradient, a cavity Q of 1.2 × 108 was measured. 6 refs., 3 figs., 2 tabs.