Hugendubel.info - Die B2B Online-Buchhandlung 

Merkliste
Die Merkliste ist leer.
Bitte warten - die Druckansicht der Seite wird vorbereitet.
Der Druckdialog öffnet sich, sobald die Seite vollständig geladen wurde.
Sollte die Druckvorschau unvollständig sein, bitte schliessen und "Erneut drucken" wählen.

Superconducting Radiofrequency Technology for Accelerators

E-BookEPUB2 - DRM Adobe / EPUBE-Book
400 Seiten
Englisch
Wiley-VCH Verlag GmbH & Co. KGaAerschienen am08.03.20231. Auflage
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.


Hasan Padamsee has published two books on radiofrequency (RF) superconductivity and one popular physics book, Unifying the Universe. After obtaining his PhD from Northeastern University, Boston, Massachusetts, he spent most of his career leading the RF Superconductivity Program at Cornell, before becoming Head of the Technical Division and Chief Technology Officer at Fermilab. At Cornell he launched the TeV Energy Superconducting Linear Accelerator (TESLA) which subsequently morphed into the International Linear Collider (ILC). He was awarded the 2015 APS Wilson Prize for his achievements in particle accelerators.mehr
Verfügbare Formate
BuchGebunden
EUR159,00
E-BookPDF2 - DRM Adobe / Adobe Ebook ReaderE-Book
EUR142,99
E-BookEPUB2 - DRM Adobe / EPUBE-Book
EUR142,99

Produkt

KlappentextSuperconducting 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.


Hasan Padamsee has published two books on radiofrequency (RF) superconductivity and one popular physics book, Unifying the Universe. After obtaining his PhD from Northeastern University, Boston, Massachusetts, he spent most of his career leading the RF Superconductivity Program at Cornell, before becoming Head of the Technical Division and Chief Technology Officer at Fermilab. At Cornell he launched the TeV Energy Superconducting Linear Accelerator (TESLA) which subsequently morphed into the International Linear Collider (ILC). He was awarded the 2015 APS Wilson Prize for his achievements in particle accelerators.
Details
Weitere ISBN/GTIN9783527836307
ProduktartE-Book
EinbandartE-Book
FormatEPUB
Format Hinweis2 - DRM Adobe / EPUB
FormatFormat mit automatischem Seitenumbruch (reflowable)
Erscheinungsjahr2023
Erscheinungsdatum08.03.2023
Auflage1. Auflage
Seiten400 Seiten
SpracheEnglisch
Dateigrösse91018 Kbytes
Artikel-Nr.11178871
Rubriken
Genre9201

Inhalt/Kritik

Inhaltsverzeichnis
Preface

PART I. UPDATE OF SRF FUNDAMENTALS
Introduction
SRF Fundamentals Review

PART II. HIGH Q FRONTIER: PERFORMANCE ADVANCES AND UNDERSTANDING
Nitrogen-Doping
High Q via 300 C° Bake (Mid-T-Bake)
High Q's from DC Magnetic Flux Expulsion

PART III. HIGH GRADIENT FRONTIER: PERFORMANCE ADVANCES AND UNDERSTANDING
High Field Q Slope (HFQS) - Understanding and Cures
Quest for Higher Gradients: Two Step Baking & N-Infusion
Improvements in Cavity Preparation
Pursuit of Higher Performance with Alternate Materials

PART IV. APPLICATIONS
New Cavity Developments
Ongoing Applications
Future Prospects for Large-Scale SRF Applications
Quantum Computing with SRF Cavities

Indexmehr
Leseprobe

2
SRF Fundamentals Review
2.1 SRF Basics

We briefly review the key figures of merit that characterize the performance of an SRF cavity or structure, referring the reader to [4, 5] for in-depth coverage. The first important parameter - the accelerating voltage Vc - is the ratio of the maximum energy gain that a particle moving along the cavity axis can achieve, to the charge of that particle. As all existing high-β multicell SRF structures operate in a Ï standing-wave mode, the optimal length (active length) of the cavity cells is βλ/2. Here λ is the rf wavelength. Next, the accelerating gradient is the ratio of the accelerating voltage per cell to the cell length, or Eacc = Vc/(βλ/2). The cavity quality factor Q0 determines the number of rf cycles (multiplied by 2Ï) required to dissipate the energy stored in the cavity. The key performance factor of an SRF cavity is typically given by the Q0 versus E curve, showing how rf losses change as the gradient (Eacc) rises. The quality factor (Q0) is derived as a ratio of two values via Rs = G/Q0, where G is the geometry factor, and Rs is the surface resistivity. As the name suggests, the geometry factor is determined only by the shape of the cavity. Surface resistivity (often referred to as surface resistance, Rs) depends only on material properties and the rf frequency. The physics of surface resistance is dominated by the physics of superconductors, and so will be a major topic of the book. The cavity s shunt impedance, Rsh, determines how much acceleration a particle can derive from a cavity for a given power dissipation, Pc in the cavity walls. Hence Rsh = Vc2/Pc. A related quantity is the geometric shunt impedance Rsh/Q0, or simply R/Q, which depends only on the cavity shape. Two other important figures of merit are the ratios Epk/Eacc and Bpk/Eacc of the peak surface electric field Epk and magnetic field Bpk to the accelerating gradient Eacc. The typical distributions of the electric and magnetic field in a single cell β = 1 cavity are shown in Figure 2.1a,b, as well as for a low-β QWR in Figure 2.1c. Note that for the single cell β = 1 cavity, the magnetic field is maximum near the equator, whereas the electric field is at a peak near the iris. Maximum electric field locations for the QWR are shown in red.

For a given accelerating field, both Epk and Hpk need to be minimized for a good design. A high surface electric field can cause field emission of electrons, which impact and heat the cavity wall, often leading to a premature breakdown of superconductivity (called quench ). Field emission electrons also generate undesirable dark current in the accelerator. A high surface magnetic field may limit the cavity s performance at high gradients if rf heating from a high resistance region (such as a defect) triggers a quench of superconductivity, or if the local field approaches the critical rf magnetic field, discussed in more detail in later chapters.

Figure 2.1 (a) Electric and magnetic field distributions for a single-cell TM010 cavity.

Source: [10] Courtesy of J. Knobloch, Cornell University. (b) Microwave Studio®[11] simulations of the electric field (left) and magnetic field (right) in a TM010 mode [12] Courtesy of D. Bafia, Illinois Institute of Technology. The phase of the magnetic field is 90° shifted relative to the phase of the electric field. (c) Electric field (left) and magnetic field (right) simulation for the QWR [13]. Zhang and Venturini Delsolaro/JACoW/CC BY 3.0.

Figure 2.2 Typical Q versus E curves obtained for cavities exhibiting various performance limiting phenomena such as: hydrogen-Q-disease, multipacting, thermal instability (or quench), field emission, or high field Q-slope (HFQS). The flat curve depicting ideal performance is rarely (or never) achieved. The X-axis for gradient is not to scale [14].

The key performance of an SRF cavity is expressed by measuring the Q0 versus Eacc curve. As shown in Figure 2.2, the Q0 departs from the ideal flat curve due to limitations arising from various phenomena such as the hydrogen-related Q-disease, multipacting, breakdown from a defect, field emission, high field Q-slope (HFQS), and medium field Q-slope (MFQS). Each of these phenomena has been extensively studied with great progress in understanding the fundamental causes. Remedies have been developed to overcome the limitations and to return cavity behavior toward the ideal, flat Q0 versus Eacc curve.

Temperature mapping of the outer wall of the cavity has played a crucial role in understanding and curing many of these limitations. Figures 2.3 and 2.4 show the earliest system [15] for rapid mapping the outer-wall temperature below the lambda point of liquid He (2.2 K). Figure 2.4 also shows a temperature map when there is heating at a defect that eventually leads to a quench at a higher field. The thermometry system shown here has been improved [16] and adopted by many labs [17-19].

The performance of an SRF cavity depends on the maximum values of the peak surface fields that can be tolerated without increasing the microwave surface resistance substantially, or without causing a breakdown of superconductivity. A high surface electric field can cause field emission of electrons, degrading the Q0. A high surface magnetic field may limit the gradient of the cavity through heating at a defect followed by thermal runaway (Figure 2.4), or through a magnetic transition to the normal state at the local critical magnetic field. The ultimate accelerating field achievable for an ideal Nb cavity is set by the rf critical magnetic field, theoretically equal to the superheating critical magnetic field [21], Hsh. For ideal niobium, Hsh at 2 K is about 0.22 T, which translates to a maximum accelerating field of about 52 MV/m for a typical shape β = 1 niobium structure, and roughly 30 MV/m for a typical β 1 Nb structure.

Figure 2.3 (a) A single thermometer board holding 21 carbon-resistor thermometers. The shape of the board matches the contour of a 1-cell cavity [10] Courtesy of J. Knobloch, Cornell University. (b) A single thermometer encased in epoxy. The sensing element is a 100 Ω Allen-Bradley carbon resistor the surface of which is ground down to just expose the carbon element for higher sensitivity.

Source: Courtesy of J. Knobloch, Cornell University. (c) Schematic of the thermometer housing showing the spring-loaded pogo stick that helps to keep contact with the cavity wall, and the leads of manganin wire to limit the stray heat input. The face of the thermometer is painted with insulation.

Source: [10, 16]/with permission of AIP Publishing LLC.

Other important design features for an SRF structure discussed further in [22] are cell-to-cell coupling for multicell structures, Lorentz-force (LF) detuning coefficient, input power required for beam power (Pb), coupling strength of input coupler (Qext), higher order mode (HOM) frequencies, HOM shunt impedances and HOM Q values. Mechanical properties also play a role in ensuring stability under atmospheric loading and temperature differentials, to minimize Lorentz-force detuning, and to keep microphonics detuning under control.

Figure 2.4 (a) Thermometers positioned on a cavity wall. Apiezon-N grease promotes thermal contact between the thermometer and the cavity wall. Some boards are removed to expose the cavity. [10, 16]. Courtesy of J. Knobloch, Cornell University & with permission of AIP through CCC. (b) Sample temperature map showing heating at a sub-mm defect site that leads to quench at higher fields. (c) At higher RF field, the defect heating grows to cause a quench of superconductivity, and a large region of the cavity surface around the defect shows high temperatures.

Source: [20]/H. Padamsee, Cornell University.
2.2 Fabrication and Processing on Nb-Based SRF Structures

To appreciate the latest progress in the performance and applications of SRF cavities it is helpful to briefly review the main features of customary fabrication and processing methods. The short review will help understand how the evolution of fabrication and surface treatment practices couple to the solution of the performance difficulties mentioned above, such as the hydrogen Q-disease, field emission and quench. More detail information about the fabrication and processing is available in [4, 5, 22].
2.2.1 Cavity Fabrication

Several industries provide niobium sheets with well-defined cavity specifications [23]. The sheets are inspected for flatness, uniform grain size...
mehr