Download or read book RF Conditioning and Testing of Fundamental Power Couplers for SNS Superconducting Cavity Production written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Spallation Neutron Source (SNS) makes use of 33 medium beta (0.61) and 48 high beta (0.81) superconducting cavities. Each cavity is equipped with a fundamental power coupler, which should withstand the full klystron power of 550 kW in full reflection for the duration of an RF pulse of 1.3 msec at 60 Hz repetition rate. Before assembly to a superconducting cavity, the vacuum components of the coupler are submitted to acceptance procedures consisting of preliminary quality assessments, cleaning and clean room assembly, vacuum leak checks and baking under vacuum, followed by conditioning and RF high power testing. Similar acceptance procedures (except clean room assembly and baking) were applied for the airside components of the coupler. All 81 fundamental power couplers for SNS superconducting cavity production have been RF power tested at JLAB Newport News and, beginning in April 2004 at SNS Oak Ridge. This paper gives details of coupler processing and RF high power-assessed performances.

Download or read book RF Conditioning and Testing of Fundamental Power Couplers for the RIA Project written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Rare Isotope Accelerator (RIA) is the highest priority of the nuclear physics community in the United States for a major new accelerator facility. A principal element of RIA will be a superconducting 1.4 GeV superconducting ion linac accelerating ions of isotopes from hydrogen to uranium onto production targets or for further acceleration by a second superconducting linac. The superconducting linac technology is closely related to that used at existing accelerators and the Spallation Neutron Source. Taking advantage of JLAB's SRF Institute facilities and expertise for the SNS project, preparation of couplers, RF conditioning and high power tests have been performed on fundamental power couplers for RIA project.

Download or read book RF Processing of the Couplers for the SNS Superconducting Cavities written by T. Powers and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: All eighty-one fundamental power couplers for the 805 MHz superconducting cavities of the SNS linac have been RF conditioned and installed in the cryomodules successfully. The couplers were RF processed at JLAB or at the SNS in ORNL: more than forty couplers have been RF conditioned in the SNS RF Test Facility (RFTF) after the first forty couplers were conditioned at JLAB. The couplers were conditioned up to 650 kW forward power at 8% duty cycle in traveling and standing waves. They were installed on the cavities in the cryomodules and then assembled with the airside waveguide transitions. The couplers have been high power RF tested with satisfactory accelerating field gradients in the cooled cavities.

Download or read book Dealing with Multipacting in Fundamental Power Couplers for SRF Cavities written by Mircea Stirbet and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Multipacting events are well known and bothersome discharge phenomena specific to vacuum and RF exposed surfaces. Left uncontrolled, these events could affect normal machine operation, limiting performance or inducing irreversible damage of critical components such as ceramic windows. Numerical simulations have been developed and their predictions fit fairly well with real multipacting events in coaxial lines or waveguide-type fundamental power couplers. Controlling multipacting must be considered from the design stage, as well as during manufacture of subassemblies or preparation of the coupler for cavity assembly. All fundamental power couplers must be conditioned using a high power RF source, and during this process, restricting multipacting by adequate instrumentation should be considered. After RF conditioning, during beam acceleration, control of multipacting is achieved with field perturbation methods. This paper summarizes our experience in dealing with multipacting in CW or pulsed fundamental power couplers (LEP, LHC, SNS and RIA) for SRF cavities. The SNS fundamental power coupler is used as an example for controlling multipacting during high power RF conditioning.

Download or read book Fundamental Power Coupler Development for Low beta Superconducting Cavities written by Jon Joseph Wlodarczak and published by . This book was released on 2008 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design and Development of EPICS Based RF Conditioning System for the High Power RF Components of Charged Particle Accelerators written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Charged particle accelerators use various vacuum windows on their accelerating RF cavities to pass very high RF power through for the acceleration of particles. The accelerating cavities and the windows should be cleaned, baked and fully RF conditioned to eliminate poor vacuum caused by outgassing and other contamination. The linear accelerator (Linac) in the Spallation Neutron Source (SNS) contains various accelerating cavity structures and RF conditioning of their high power vacuum windows is necessary for present work as well as future upgrade and development. An example is the coaxial fundamental power coupler (FPC) with an annular alumina ceramic window for each of the 81 superconducting RF cavities in the SNS Linac. The FPC's need to be tested up to 650 kW peak in traveling wave and 2.6 MW in standing wave in 1.3 microsecond 60 pulses per second RF. 805 MHz, 550-kW klystrons (700 kW maximum) are the main power source of the superconducting Linac and the conditioning power source of the FPC's. The conditioning process has to be controlled very carefully not to damage the window; with the high power RF the initial vacuum is unpredictable and any unsafe vacuum level can damage the high quality ceramic windows. In this thesis, an Experimental Physics and Industrial Control System (EPICS) controlled RF conditioning system for the SNS RF Test Facility (RFTF) has been presented. Various RF and control instruments are integrated through the EPICS system on Linux platform to measure and to control the vacuum and the RF power while monitoring electron emission and unwanted arcing during the conditioning. Monitoring arcing at the window and flow and temperature of cooling water in high power RF load and ceramic window is necessary to interlock the RF not to have any kind of undesirable operation condition. The interlock system has been designed by using the Programmable Logic Controller (PLC) and an RF switch with microseconds response time. Usually the whole conditioning process takes several days, so it is necessary to get the flexibility to control, monitor, and archive the system operation remotely along with good upgradeability. To get these advantages in EPICS, VXI/VME based Input and Output Controller (IOC)s are used for controlling and monitoring the RF conditioning system. This thesis summarizes all the hardware and software design strategies, provides the results obtained so far at room temperature and describes the future research scope.

Download or read book State of the Art Power Couplers for Superconducting RF Cavities written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Simulations are now routinely performed that allow the prediction of electromagnetic, multipacting, thermal, and mechanical properties of couplers. From these studies, better designs have been conceived which can minimize potential problems ahead of construction. Judicious use of materials and the implementation of clean practices and of careful conditioning have gradually increased the power levels at which couplers can safely operate. Machine operation at hundreds of kilowatts has been achieved in CW at KEK and Cornell, and in a pulsed mode at the TESLA Test Facility (TTF). Test stand operations in CW at the megawatt level (Accelerator for the Production of Tritium) and in pulse mode at a peak power of 2 MW (Spallation Neutron Source, TTF version II) have been achieved. The recent progress indicates that the understanding of the behavior of fundamental power couplers is rapidly increasing and that optimal designs are being developed which will allow in the future to attain routine attainment of the megawatt power levels necessary for high-beam-power machines under construction and under study.

Download or read book State of the Art Couplers for Superconducting RF Cavities written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamental power couplers for RF particle accelerators are the most important components that interface with the accelerating structures. In the case of superconducting cavities, the main function of providing the appropriate amount of power to the cavity's fields and to the beams is dwarfed by the requirements that the couplers must meet in order to harmoniously blend into the vacuum, cryogenic, and electromagnetic environment. Recently, a lot of progress has been made in the areas critical to the successful design, construction, and operation of fundamental power couplers. Simulations are now routinely performed that allow the prediction of electromagnetic, multipacting, thermal, and mechanical properties of couplers. From these studies, better designs have been conceived which can minimize potential problems ahead of construction. Judicious use of materials and the implementation of clean practices and of careful conditioning have gradually increased the power levels at which couplers can safely operate. Machine operation at hundreds of kilowatts has been achieved in CW at KEK and Cornell, and in a pulsed mode at the TESLA Test Facility (TTF). Test stand operations in CW at the megawatt level (Accelerator for the Production of Tritium) and in pulse mode at a peak power of 2 MW (Spallation Neutron Source, TTF version II) have been achieved. The recent progress indicates that the understanding of the behavior of fundamental power couplers is rapidly increasing and that optimal designs are being developed which will allow in the future to attain routinely megawatt power levels necessary for high beam power machines under construction and under study.

Download or read book An Over moded Fundamental Power Coupler for the ILC written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The current design of fundamental power couplers for the ILC are expensive and require excessively long conditioning times. The goal of this develoment is design of a coupler that requires little rf processing and is significantly less expensive to build than the present ILC coupler. The goal of this program is development of a new technology for power couplers. This new technology is based on the cylindrical TE01 mode and other over-moded technologies developed for the X-band rf distribution system of the NCLTA. During the Phase I program, a TE10 to TE01 mode transducer suitable for use as a part of a power coupler in the ILC will be designed, built and tested. Following a succesful test, prototype designs of the TE01 to cavity coupler and thermal will be produced. A detailed study of the suitability of this overmoded waveguide technology for the ILC power coupler will be provided in the final report. Development of over-moded power couplers for superconducting cavities could find application im many world-wide accelerator projects, such as SNS, Jefferson Lab upgrade, RIA, TESLA in addition to the ILC.

Download or read book Fundamental Power Couplers for Superconducting Cavities written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamental power couplers (FPC's) for superconducting cavities must meet very strict requirements to perform at high power levels (hundreds of kilowatts) and in a variety of conditions (CS, pulsed, travelling wave, standing wave) without adversely affecting the performance of the cavities they are powering. Producing good coupler designs and achieving operational performances in accelerator environments are challenging tasks that have traditionally involved large resources from many laboratories. The designs involve state-of-the-art activities in RF, cryogenic and mechanical engineering, materials science, vacuum technology, and electromagnetic field modeling. Handling, assembly and conditioning procedures have been developed to achieve ever-increasing power levels and more reliable operation. In this paper, the technical issues associated with the design, construction, assembly, processing, and operation of FPC's will be reviewed, together with the progress in FPC activities in several laboratories during the past few years.

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 Tuner Effect on the Field Flatness of SNS Superconducting RF Cavity written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The field flatness (FF) in a multi-cell superconducting cavity affects not only net accelerating voltage, but also peak surface field [1] and Lorentz detuning coefficient [2]. Our measurements indicate that the tuner's motion changes not only the cavity frequency but also its FF. This field amplitude change is a linear tilt and proportional to the distance between each cell center and the cavity's geometric center. This tilt also changes the coupling of the Fundamental Power Coupler (FPC) and Field Probe (FP) on either side of the cavity. The tilt has been measured and simulated, and is ≈20%/MHz on the Spallation Neutron Source (SNS) medium [beta] cavities. The FF change is not only due to the uneven volume change within the cell, but also due to the cell-to-cell coupling.

Download or read book RF Design and Processing of a Power Coupler for Third Harmonic Superconducting Cavities written by and published by . This book was released on 2007 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: The FLASH user facility providing free electron laser radiation is built based on the TTF project at DESY. Fermilab has the responsibility for the design and processing of a third harmonic, 3.9 GHz, superconducting cavity which is powered via a coaxial power coupler. Six power couplers have been manufactured at CPI after successful design of the power coupler including RF simulation, multipacting calculation, and thermal analysis. The power couplers are being tested and processed with high pulsed power in an elaborate test stand at Fermilab now. This paper presents the RF design and processing work of the power coupler.

Download or read book Development of Fundamental Power Coupler for High current Superconducting RF Cavity written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Brookhaven National Laboratory took a project of developing a 704 MHz five-cell superconducting RF cavity for high-current linacs, including Energy Recovery Linac (ERL) for planned electron-hadron collider eRHIC. The cavity will be fed by a high-power RF amplifier using a coaxial Fundamental Power Coupler (FPC), which delivers 20 kW of CW RF power to the cavity. The design of FPC is one of the important aspects as one has to take into account the heat losses dissipated on the surface of the conductor by RF fields along with that of the static heat load. Using a simple simulation model we show the temperature profile and the heat load dissipated along the coupler length. To minimize the heat load on FPC near the cavity end, a thermal intercept is required at an appropriate location on FPC. A 10 K intercept was chosen and its location optimized with our simulation code. The requirement on the helium gas flow rate for the effective heat removal from the thermal intercept is also discussed.

Download or read book RF Superconductivity written by Hasan Padamsee and published by John Wiley & Sons. This book was released on 2009-04-20 with total page 465 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 Results of the APT RF Power Coupler Development for Superconducting Linacs written by and published by . This book was released on 2001 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the new baseline APT (Accelerator Production of Tritium) linac design, the power couplers are required to transmit 420 kW of CW RF power to the superconducting cavities at 700 MHz. These couplers consist of an airside waveguide-to-coax transition, an air/vacuum break made by two planar, coaxial windows, and a vacuum-side coaxial antenna section. The coaxial antenna allows adjustability of the RF matching to the superconducting cavities. Design, fabrication, and testing of the power coupler/window occurred over the last four years, and room temperature testing of the prototype design is complete. Coupler/window assemblies have transmitted power to 1 MW, CW and have handled full reflected 850 kW, CW over a limited standing-wave phase range. Couplers were tested with a portion of the outer conductor cooled by liquid nitrogen to study the effects of condensed gases. No hard multipacting barriers were encountered during any of this room temperature testing. Final results, conclusions, and lessons learned about the coupler design, fabrication, and testing will be discussed.

Download or read book High Power RF Tests on Input Couplers for 972 MHz Superconducting Cavities in the J PARC Project written by E. Kako and published by . This book was released on 2003 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: