Download or read book Thermal Conductivity of Superconducting Niobium from 0 03k to 4k written by Stephen Carroll Smith and published by . This book was released on 1971 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermal Conductivity of Superconducting Niobium written by Byron Keith Moore and published by . This book was released on 1971 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermal Conductivity and Thermal Effects in Superconducting Niobium written by Syed Mohammad Wasim and published by . This book was released on 1970 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermal Conductivity of Superconducting Niobium written by Jon Ross Carlson and published by . This book was released on 1968 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Role of Metallurgy in the Thermal Conductivity of Superconducting Niobium written by Saravan Kumar Chandrasekaran and published by . This book was released on 2013 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of the Thermal Transport in Superconducting Niobium and Tantalum written by Peng Xu and published by . This book was released on 2019 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Superconducting radio frequency (SRF) cavities fabricated from bulk high purity niobium (Nb) are increasingly used for particle accelerators to achieve continuous operation. Even in the superconducting regime, residual resistance and small imperfections on the RF surface can dissipate energy and cause local heating that leads to cavity quench. Large values of thermal conductivity can mitigate local temperature excursions and prevent cavity quench, thus improving cavity performance. Understanding thermal transport in bulk and thin film superconducting Nb may guide thermal design of current and next generation SRF cavities.The thermal conductivity of metals is composed of electronic and lattice (phonon) components. In normal conductors, the electronic component dominates, and in superconducting metals, as the temperature drops below the critical temperature, phonons become increasingly important carriers of thermal energy. A widely used model of thermal conductivity in superconductors omits explicit accounting of the effect of dislocations, which result from deformation. Here, this model is extended by accounting for the effects of phonons scattered by dislocations independent from boundary scattering. This extended model agrees better with measurements of thermal conductivity in deformed Nb samples, especially at temperatures T less than 3 K. An apparent threshold of dislocation density Nd is found to be Nd = O(1012) m−2 for Nb and when applied to tantalum (Ta), it is Nd = O(1011) m−2. There is little contribution to the thermal conductivity when the dislocation density is less than this threshold. This model can also be used to estimatethe dislocation density by fitting measured values of thermal conductivity.Examination of thermal conductivity data for superconducting Nb shows that there is often a local maximum, a so-called phonon peak, kpp. The temperature at which this kpp occurs Tpp is between 1.72 K and 2.35 K and shifts for samples after deformation. It is well known that the magnitude of kpp decreases as the material is deformed, and hence with increasing Nd. Less cited is that Tpp increases with increasing Nd. This may affect the operating temperature of an SRF cavity. At a certain level deformation (i.e., 4.7% deformation for a residual resistivity ratio RRR = 185), the phonon peak disappears. More deformation is needed for higher RRR, (i.e., greater purity).The models discussed above require estimating several parameters from thermal conductivity measurements and may be best suited to explaining the relative importance of the several scattering mechanisms. For predicting thermal conductivity from basic material variables, the Boltzmann transport equation (BTE) is solved by two methods to predict the lattice component of thermal conductivity. One method uses a substitution of variables from frequency to wavevector in the Callaway model to include the nonlinear phonon dispersion relationship for the longitudinal acoustic (LA) and transverse acoustic (TA) phonon polarizations. This model incorporates a relaxation time approximation using Matthiessen's rule to consider phonon scattering by electrons, boundaries, and dislocations. Another method to predict the lattice thermal conductivity uses an energy-based, variance-reduced Monte Carlo (MC) solution to the BTE for phonons. The MC solution allows more general consideration of the individual scattering mechanisms. It may also be generalized for more complex geometries. The MC solution technique was first verified by comparing the predicted thermal conductivity in bulk Si and Si nanowires with experimental results. Both solutions of the BTE for the lattice thermal conductivity of undeformed and deformed superconducting Nb agreed well with experimental values. The MC model was also used to demonstrate that interstitial impurities must be near saturation to change the lattice thermal conductivity of Nb. The MC solution was also effective in predicting the lattice thermal conductivity of superconducting Ta, with the appropriate change in dispersion relation and other material parameters.

Download or read book Superconducting Properties of Niobium Films written by Wayne R. Hudson and published by . This book was released on 1971 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermal Transport and Thermal magnetic Breakdown in Superconducting Cavities Made of High Thermal Conductivity Niobium written by Kathleen Rempel Krafft and published by . This book was released on 1983 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comprehensive Dissertation Index 1861 1972 Physics M Z written by Xerox University Microfilms and published by . This book was released on 1973 with total page 936 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermal Design Studies in Niobium and Helium for Superconducting Radio Frequency Cavities written by Ahmad Aizaz and published by . This book was released on 2006 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1973 with total page 964 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Superconducting Cavities from High Thermal Conductivity Niobium for CEBAF February 1991 written by Peter Kneisel and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Superconductivity Cavities from High Thermal Conductivity Niobium for CEBAF January 1991 written by Peter Kneisel and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Aspects of Quantum Computing written by Henry O. Everitt and published by Springer Science & Business Media. This book was released on 2007-04-03 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: Practical quantum computing still seems more than a decade away, and researchers have not even identified what the best physical implementation of a quantum bit will be. There is a real need in the scientific literature for a dialogue on the topic of lessons learned and looming roadblocks. This reprint from Quantum Information Processing is dedicated to the experimental aspects of quantum computing and includes articles that 1) highlight the lessons learned over the last 10 years, and 2) outline the challenges over the next 10 years. The special issue includes a series of invited articles that discuss the most promising physical implementations of quantum computing. The invited articles were to draw grand conclusions about the past and speculate about the future, not just report results from the present.

Download or read book Superconductivity and Its Applications written by Yi-Han Kao and published by American Institute of Physics. This book was released on 1992 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Matter and Methods at Low Temperatures written by Frank Pobell and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this book is to provide information about performing experi ments at low temperatures, as well as basic facts concerning the low tem perature properties of liquid and solid matter. To orient the reader, I begin with chapters on these low temperature properties. The major part of the book is then devoted to refrigeration techniques and to the physics on which they are based. Of equal importance, of course, are the definition and measurement of temperature; hence low temperature thermometry is extensively discussed in subsequent chapters. Finally, I describe a variety of design and construction techniques which have turned out to be useful over the years. The content of the book is based on the three-hour-per-week lecture course which I have given several times at the University of Bayreuth between 1983 and 1991. It should be particularly suited for advanced stu dents whose intended masters (diploma) or Ph.D. subject is experimental condensed matter physics at low temperatures. However, I believe that the book will also be of value to experienced scientists, since it describes sev eral very recent advances in experimental low temperature physics and technology, for example, new developments in nuclear refrigeration and thermometry.