The Advanced Photon Source (APS) storage ring (SR) rf system employs four banks of four spherical, single-cell resonant cavities. Each cavity is tuned by varying the cavity volume through insertion/retraction of a copper piston located at the circumference of the cavity and oriented perpendicular to the ...
Energy Citations Database
Energen, Inc. has designed, built, and demonstrated several fast and slow tuners based on its magnetostrictive actuators and stepper motor. These tuners are designed for Superconducting Radio Frequency (SRF) cavities, which are important structures in par...
National Technical Information Service (NTIS)
A coaxial blade tuner has been selected for the 1.3GHz SRF cavities of the Fermilab SRF Accelerator Test Facility. Results from tuner cold tests in the Fermilab Horizontal Test Stand are presented. Fermilab is constructing the SRF Accelerator Test Facility, a facility for ...
Energen, Inc. has designed, built and demonstrated a fine tuning mechanism for superconducting radio frequency (SRF) cavities used in particle accelerators. This tuner is based on giant magnetostrictive materials being developed by Energen, Inc. Magnetostrictors elongate when exposed to a small magnetic field. This extension is ...
DOE Information Bridge
Page 1. A HYDROGEN MASER !I TH CAVITY AUTO- TUNER ... 4. TITLE AND SUBTITLE A Hydrogen Maser with Cavity Auto-Tuner for Timekeeping ...
DTIC Science & Technology
Analysis and modeling is presented for a fast microwave tuner to operate at 700 MHz which incorporates ferroelectric elements whose dielectric permittivity can be rapidly altered by application of an external voltage. This tuner could be used to correct unavoidable fluctuations in the resonant frequency of superconducting cavities in ...
Energen, Inc. has designed, built, and demonstrated several fast and slow tuners based on its magnetostrictive actuators and stepper motor. These tuners are designed for Superconducting Radio Frequency (SRF) cavities, which are important structures in particle accelerators that support a wide spectrum of ...
A novel tuner has been developed by the Omega-P company to achieve fast control of the accelerator RF cavity frequency. The tuner is based on the ferroelectric property which has a variable dielectric constant as function of applied voltage. Tests using a Brookhaven National Laboratory (BNL) 1.3 GHz electron gun ...
A single-cavity test cryostat is used to conduct pulsed high power RF tests of superconducting 1.3 GHz RF cavities at 2 K. The cavities under test are welded inside individual helium vessels and are outfitted ('dressed') with a fundamental power coupler, higher-order mode couplers, magnetic shielding, a blade ...
When an SRF accelerator is designed, there is motivation to move the cavities close together on the beamline. Assuming the beamline apertures are not shrunk as well, this compaction (which will increase the overall accelerating gradient and/or lower the dynamic cryogenic heat load) increases the inter-cavity ...
Traditionally ferrites have been used in accelerators for tuning rf cavities and in nonreciprocal devices controlling the power flow in rf accelerating systems. Recently, the development of cavity tuners based on perpendicularly biased ferrites has shown good progress. Yttrium iron garnet (YIG) ...
A superconducting third harmonic 3.9 GHz accelerating cavity was proposed to improve the beam quality in the TTF-like photoinjector [1]. Fermilab has developed, built and tested several prototypes, including two copper 9-cell cavities, one niobium 3-cell cavity, and one 9-cell cavity. The ...
Pulsed operation of superconducting cavities can induce large variations of the resonant frequency through excitation of the mechanical modes by the radiation pressure. The phase and amplitude control system must be able to accommodate this frequency variation; this can be accomplished by increasing the capability of the rf power source. Alternatively, a piezo electric ...
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 ...
At the Continuous Electron Beam Accelerator Facility (CEBAF), a 4 GeV, multipass CW electron beam is to be accelerated by 338 SRF, 5-cell niobium cavities operating at a resonant frequency of 1497 MHz. Eight cavities arranged as four pairs comprise a cyromodule, a croygenically isolated linac subdivision. The ...
The Continuous Electron Beam Accelerator (CEBA) uses mechanical tuners at 2 K driven by room temperature stepping motors in a feedback loop to maintain cavity frequency at 1497 MHz. Modification of the system was designed, replacing a passive section of the mechanical tuner with a magnetostrictive tuning element ...
... Accession Number : ADA519500. Title : A Hydrogen Maser with Cavity Auto-Tuner for Timekeeping. Descriptive Note : Conference paper. ...
A periodically Higher Order Mode (HOM) damped RF cavity is a weakly coupled multi-cell RF cavity with HOM couplers periodically mounted between the cells. It was studied as an alternative RF structure between the single cell cavity and superstructure cavity in high beam current application requiring strong damping ...
The resonant frequency of an accelerating RF cavity is detuned from the desired frequency by certain physical disturbances, such as thermal and other mechanical wall distortions. Cavity wall distortions due to microphonics (acoustic vibrations) and the Lorentz force (radiation pressure) can be serious problems in pulsed RF operation of ...
This report describes a ferrite tuner design for the LEB cavity that utilizes techniques for bonding ferrite to metallic cooling plates that is utilized in the high-power rf and microwave industry. A test tuner was designed to fit into the existing LEB-bu...
is under construction to house the expansion. 2 CRYOMODULE DESIGN A prototype of the medium beta cryomodule filter and delivered to the cavity through a 2 m long ro� tating wand outfitted with a nozzle The mechanical tuner alters the resonant frequency of the cavity by deflection of a niobium tuning plate
E-print Network
A transmission-line model has been used in the design of a ferrite-tuned prototype rf cavity for a hadron-facility main ring. The computer codes SUPERFISH and MAFIA were used to refine and validate the transmission line model representations for the accelerating gap, the coaxial tee, and the ferrite tuner assembly. 5 refs., 9 figs., 4 ...
A prototype rf cavity and rf drive system for a hadron facility main ring has been designed and will be tested in the Proton Storage Ring (PSR) at Los Alamos as a part of a collaborative effort between LANL and TRIUMF. The cavity uses an orthogonally biased ferrite tuner. The design provides for accelerating gap ...
An upgrade cryomodule is being developed for CEBAF at Jefferson Lab. The high-gradient, low-current operation of the superconducting cavities puts stringent requirements on the accuracy of the frequency tuner: a resolution of 1 Hz over a range of 400 KHz. We have developed and tested such a tuner; it consists of a stepper-motor-driven ...
The listed drawings and subsequent referenced drawings therein provide the data and specifications for construction of the phase lock, gap voltage, and frequency control systems used to control the rf accelerating cavity parameters of the Stanford Linear Accelerator Center's PEP storage ring. The phase lock portion is a phase ...
The Spallation Neutron Source (SNS) project incorporates a superconducting radio-frequency (SRF) accelerator for the final section of the pulsed mode linac. Cavities with geometrical {beta} values of {beta}=0.61 and {beta}=0.81 are utilized in the SRF section, and are constructed out of thin-walled niobium with stiffener rings welded between the cells near ...
The Spallation Neutron Source (SNS) project incorporates a superconducting radio-frequency (SRF) accelerator for the final section of the pulsed mode linac Cavities with geometrical {beta} values of {beta} = 0.61 and {beta} = 0.81 are utilized in the SRF section, and are constructed out of thin-walled niobium with stiffener rings welded between the cells ...
An RF powered electrodeless lamp utilizing an inductive tuner in the waveguide which couples the RF power to the lamp cavity, for reducing reflected RF power and causing the lamp to operate efficiently.
The new tuner design for the 12 GeV Upgrade SRF cavities consists of a coarse mechanical tuner and a fine piezoelectric tuner. The mechanism provides a 30:1 mechanical advantage, is pre-loaded at room temperature and tunes the cavities in tension only. Al...
The limited cavity beam loading conditions anticipated for the Rare Isotope Accelerator (RIA) create a situation where microphonic-induced cavity detuning dominates radio frequency (RF) coupling and RF system architecture choices in the linac design process. Where most superconducting electron and proton linacs have beam-loaded ...
The new digital LLRF system for the CEBAF 12GeV accelerator will perform a variety of tasks, beyond field control [1]. In this paper we present the superconducting cavity resonance control system designed to minimize RF power during gradient ramp and to minimize RF power during steady state operation. Based on the calculated detuning angle, which ...
An rf cavity and drive system have been designed for the proposed Heavy Ion Storage Ring for Atomic Physics,'' HISTRAP, at Oak Ridge. A peak accelerating voltage of 2.5 kV per turn is required with a continuous tuning range from 200 kHz through 2.7 MHz. A single-gap, half-wave resonant configuration is used with biased ferrite tuning. ...
When a microwave cavity in coaxial systems is operated in a helium cryostat, optimum coupling of cables to the cavity involves impedance matching between the cables and the cavity. This matching problem is solved by a rightangle stub tuner which can be operated in liquid helium. (D.L.C.)
A 6-cell 805 MHz superconducting cavity for acceleration in the velocity range of about 0.4 to 0.53 times the speed of light was designed. After single-cell prototyping, three 6-cell niobium cavities were fabricated. In vertical RF tests of the 6-cell cavities, the measured quality factors (Q{sub 0}) were between 7 ...
An rf accelerating cavity appropriate for use in a 20% frequency bandwidth synchrotron has been designed, fabricated, and is now being tested at Los Alamos. The cavity-amplifier system was designed to produce a peak rf gap voltage of 90 kV over the range from 50 to 60 MHz. Special features of the system are the transversely biased ...
An accelerating RF cavity usually requires accessory devices such as a tuner, a coupler, and a damper to perform properly. Since a device is attached to the wall of the cavity to have certain electrical coupling of the cavity field through the opening. RF power dissipation is involved. In a ...
A new type of ferrite tuner has been tested at the BNL. The ferrite tuner uses garnet slabs partially filling a stripline. One of the important features of the tuner is that the ferrite is perpendicularly biased for operation above FMR, thus reducing the magnetic losses. A unique design was adopted to achieve the efficient cooling. The ...
For the ELBE electron linear accelerator a superconducting accelerating module was developed and is now in routine operation. The cryostat contains two TESLA cavities (1.3 GHz) and is designed for continuous-wave (CW) operation with an accelerating gradient of 10 MV/m and a maximum average beam current of 1 mA. For ...
NASA Astrophysics Data System (ADS)
The 28 MHz accelerating system consists of a quarter wave cavity driven by an inductively coupled 100kW tetrode amplifer and 1kW solid state driver amplifer. 40dB of rf feedback closed around the cavity and amplifers reduces small perturbations within the loop by a factor of 100, and reduces the time required to shift the phase at ...
The new tuner design for the 12 GeV Upgrade SRF cavities consists of a coarse mechanical tuner and a fine piezoelectric tuner. The mechanism provides a 30:1 mechanical advantage, is pre-loaded at room temperature and tunes the cavities in tension only. All of the components are located in the ...
The design concepts for ferrite-tuned accelerating cavities discussed in this paper differ from conventional solutions using thick ferrite toroids for frequency tuning. Instead, tuners consisting of an array of ferrite-loaded striplines are investigated. These promise more efficient cooling and higher operational reliability. Layout ...
The design concepts for ferrite-tuned accelerating cavities discussed in this paper differ from conventional solutions using thick ferrite toroids for frequency tuning. Tuners consisting of an array of ferrite-loaded striplines are investigated. These promise more efficient cooling and higher operational reliability. Layout examples ...
An upgrade of the existing proton and deuteron accelerator facility COSY at the Forschungszentrum Juelich, based on a superconducting linac is under investigation. This paper will report on the cryogenic aspects of the project: The cryomodule layout will be shown and special emphasis will put on the short cold-warm transition, the heat transfer of which was calculated using ...
High intensity proton beams, in the multi-MW range (typically 1 GeV and a few mA) are considered today for different applications: neutron sources, nuclear waste transmutation, radioactive ion beams and neutrino factories. All the foreseen projects are based on superconducting RF cavities for the high energy part of the linac accelerator between 100 MeV ...
The planned upgrade of the CEBAF electron accelerator includes the development of an improved cryomodule. Several components differ substantially from the original CEBAF cryomodule; these include: the new 7-cell, 1.5 GHz cavities with integral helium vessel, a new, backlash-free cavity tuner, the waveguide coupler ...
A 352-MHz fast-ferrite rf cavity tuner, manufactured by Advanced Ferrite Technology, was high-power tested on a single-cell copper rf cavity at the Advanced Photon Source. These tests measured the fast-ferrite tuner performance in terms of power handling capability, tuning bandwidth, tuning speed, stability, and rf ...
A 10 cm diameter by 5 cm travel plunger tuner was developed for the PEP-II RF copper cavity system. The single cell cavity including the tuner is designed to operate up to 150 kW of dissipated RF power are specially placed 8.5 cm away from the inside wall of the cavity to avoid fundamental and ...
Microphonic-induced fluctuations in the RF eigenfrequency of superconducting (SC) slow-wave structures must be compensated by a fast-tuning system in order to control the RF phase. The tuning system must handle a reactive power proportional to the product of the frequency range and the RF energy content of the Rf cavity. The fast tuner for the SC ...
The Infrared Free Electron Laser being constructed at the Thomas Jefferson National Accelerator Facility will require a 42 MeV, 5 mA electron accelerator. The accelerator design requires a 10 MeV injector and a two pass 32 MeV linac, one pass for acceleration and one pass for energy recovery. In order to minimize ...
A new cryomodule containing seven low-beta superconducting radio frequency (SRF) cavities has been added to the ATLAS heavy ion linac, providing an additional 15 MV accelerating potential to the existing accelerator. We describe the final stages of cryomodule assembly, commissioning, and installation in the ATLAS ...
The Low Level RF (LLRF) system is the source of all of the rf signals required for an rf linear accelerator. These signals are amplified to drive accelerator and buncher cavities. It can even provide the synchronizing signal for the rf power for a synchrotron. The use of Direct Digital Synthesis (DDS) techniques results in a versatile ...
The Thomas Jefferson National Accelerator Facility (Jefferson Lab, formerly known as CEBAF) is building a highly efficient, kilowatt-level infrared free-electron laser, the IR Demo FEL. The IR FEL uses superconducting radio-frequency (SRF) cavities to accelerate the electron beam that provides energy for the laser. These ...
The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built at Oak Ridge National Laboratory. A conventional 402.5-MHz drift-tube linac (DTL) accelerates the H{sup -} beam from 2.5 to 86 MeV, followed by a 805-MHz coupled-cavity linac (CCL) to 186 MeV. Tuning the six DTL tanks involves adjusting post-coupler ...
When complete, the Continuous Electron Beam Accelerator Facility will house a 4 GeV recirculating linear accelerator containing 42 1/4 cryomodules arrayed in two antiparallel linacs and an injector. Currently, over half of the cryomodules have been installed. Each cryomodule contains eight superconducting niobium 5-cell rf cavities ...
Front end of a CW linac of the Project X contains an H{sup -} source, an RFQ, a medium energy transport line with the beam chopper, and a SC low-beta linac that accelerates H{sup -} from 2.5 MeV to 160 MeV. SC Single Spoke Resonators (SSR) will be used in the linac, because Fermilab already successfully developed and tested a SSR for beta = 0.21. Two manufactured ...
The ECX Project, Brookhaven Lab's predecessor to the RHIC e-Cooler, includes a prototype RF tuner mechanism capable of both coarse and fast tuning. This tuner concept, adapted originally from a DESY design, has longer stroke and significantly higher loads attributable to the very stiff ECX cavity shape. Structural design, ...
The status of the Rossendorf superconducting RF gun is discussed. This gun allows continuous wave operation with an energy of 9.5 MeV and an average current of 1mA. The 3 cell niobium cavity contains a normal conducting photocathode. A special choke flange filter at the cathode side prevent the RF leakage of the cavity. The design of the ...
Three 500 MHz cavities are used in the Booster and Storage Ring of the Advanced Light Source (ALS). Due to different varying parameters, a control system is required to keep the cavities in tune during operation. The tuning of the 500 MHz cavity is achiev...
The fundamental mode frequency of the prototype storage ring cavity has been measured with various port terminations and cavity temperatures. Since the highest tuned frequency of the prototype cavity with a tuner under the high RF power test condition is ...
At the Forschungszentrum Dresden-Rossendorf the development and the setup of the 2nd superconducting radio frequency photo electron injector (SRF-Photo-Gun) is finished. This new injector is placed next to the existing thermionic gun of the superconducting linear accelerator ELBE. A connection between the accelerator and the SRF-Gun will provide improved ...
Microphonic fluctuations in the rf eigenfrequency of superconducting (SC) slow-wave structures must be compensated by a fast-tuning system in order to control the rf phase. The tuning system must handle a reactive power proportional to the product of the tuning range and the rf energy content of the resonant cavity. The accelerating field level of many of ...
Fermilab is developing 325 MHz SRF spoke cavities for the proposed Project X. A compact fast/slow tuner has been developed for final tuning of the resonance frequency of the cavity after cooling down to operating temperature and to compensate microphonics and Lorentz force detuning [2]. The modified tuner design ...
In superconducting accelerators, requirements for frequency, amplitude, and phase control are different from those used for normal conducting activities. Superconducting cavities have a very narrow bandwidth and are therefore highly sensitive to mechanical perturbations. Significant phase and amplitude errors are induced by the resulting frequency ...
The 352-MHz rf power dissipated in each APS storage ring cavity reaches about 70 kW for conditioning and 40 kW for 7-GeV operation. Each cavity is equipped with an adjustable-plunger tuner. Initial operation of the cavities showed unexpected higher temperatures in some tuners due to rf heating ...
The technology for mechanically compensating Lorentz Force detuning in superconducting RF cavities has already been developed at DESY. One technique is based on commercial piezoelectric actuators and was successfully demonstrated on TESLA cavities. Piezo ...
A new fast autotuner for the hydrogen maser was implemented. By modulating the cavity, a phase shift in the maser output signal is induced which is proportional to the cavity tuning error. The phase shift is detected and fed back to a varactor tuner to st...
Jefferson Lab has developed a prototype of the medium beta SNS cryomodule. Tests were recently performed on the module, which includes three 805 MHz cavities of beta=0.61, with coaxial power couplers and frequency tuners (mechanical and piezoelectric). The cavities exceeded accelerating gradients of 16 MV/m (design ...
A compact injector for medical accelerators was designed. The injector consists of a compact Electron-Cyclotron-Resonance Ion Source (ECRIS) and two linacs, which are a Radio-Frequency-Quadrupole (RFQ) linac and an Interdigital H-mode Drift-Tube-Linac (IH-DTL) having the same operating frequency of 200 MHz. For beam focusing of the IH-DTL, the method of ...
A proposed design of a closed shell tuner for the LEB cavity is presented. The tuner is made out of Ti alloy which has a high electrical resistivity as well as very good mechanical strength. Using this alloy results in a substantial reduction in the eddy current heating as well as allowing for faster frequency control. 9 figs.
A proposed design of a closed shell tuner for the LEB cavity is presented. The tuner is made out of Ti alloy which has a high electrical resistivity as well as very good mechanical strength. Using this alloy results in a substantial reduction in the eddy current heating as well as allowing for faster frequency control.
The choice of the loaded quality factor (QL) of a superconducting cavity is driven by many factors, including beam loading effects and microphonics. In accelerators with minimal beam loading, use of SRF cavities with relatively high loaded-Q allows one to employ lower power RF sources. Many individuals are therefore considering ...
The new SL21 cryomodule is the first 70MeV, 8-cavity string superconducting accelerator module to be installed in CEBAF. Each cavity has 7-cells, the center cells have Mark II shape and the end cells have the Mark III shape. The HOM couplers resemble the DESY welded type; two of them assembled at one end of a ...
... Aluminum foil tuners provided mode-mixing. Normalized cavity power density was the ratio of received power to input power. ...
Description is given of a preliminary conceptual design for a tuner that employs a new ferroelectric ceramic that allows fast changes in coupling between the SRF acceleration structure of a linac and the external RF feeding line. The switching time of this device is in the range of a few microseconds. Utilization of this tuner is ...
Acceleration effects on resonant frequencies of electromagnetic cavity, using constitutive equations
NASA Technical Reports Server (NTRS)
A new engineering design of ferrite tuners for rapid-cycling-booster rf cavities is proposed. The basic concept is to divide a perpendicularly biased ferrite tuner into two (or more) successive or parallel sections which are magnetically biased in opposite directions. This approach aims at several improvements with respect to existing ...
A two-cell 425-MHz drift-tube linac (DTL) ''sparker'' for operation at 20 K has been designed and constructed to operate at >2 Kilpatrick accelerating voltage while transporting an H/sup /minus// 5-MeV beam at currents up to 100 mA. Permanent-magnet quadrupole (PMQ) assemblies are installed in the input/output beam-transport system and in ...
Three 500 MHz cavities are used in the Booster and Storage Ring of the Advanced Light Source (ALS). Due to different varying parameters, a control system is required to keep the cavities in tune during operation. The tuning of the 500 MHz cavity is achieved by detecting the phase error between the drive signal and the ...
Since 1991 the superconducting Darmstadt linear accelerator S-DALINAC provides an electron beam of up to 130 MeV for nuclear and astrophysical experiments. The accelerator consists of an injector and four main linac cryostats, where the superconducting cavities are operated in a liquid helium bath at 2 K. Currently, the injector ...
A three-dimensional computational heat transfer and fluid flow model was developed to analyze a forced-flow, liquid-cooled, low energy booster (LEB) radio-frequency (RF) cavity tuner concept. The results for a commercial dielectric heat transfer fluid indicated safe temperatures in the ferrite.
The LHC RF consists of eight superconducting single-cell 400.8 MHz cavities per beam, with each cavity driven by a 300 kW klystron via a circulator and waveguide. As the LHC is a high current collider (nominal 0.6 A DC), the challenge is to keep the effective impedance of the cavity at a minimum and to reduce all sources of RF noise ...
The r.f cavity design for the Booster, vuv ring and x-ray ring of the NSLS is described together with the mechanical design of tuners, coupling and monitoring loops and the temperature control systems. The results of higher order mode measurements as comp...
The r.f cavity design for the Booster, vuv ring and x-ray ring of the NSLS is described together with the mechanical design of tuners, coupling and monitoring loops and the temperature control systems. The results of higher order mode measurements as compared with Superfish calculations are also presented.
Upgraded versions of cavities for the APS positron accumulator ring (PAR) have been built and are being tested. Two cavities are in the PAR: a fundamental 9.8-MHz cavity and a twelfth harmonic 117.3-MHz cavity. Both cavities have been manufactured for higher voltage operation with improved ...
Returning of the 201.25-MHz accelerator structure field distributions after the 1975 shutdown is described, and final data are given for use in beam dynamics studies. Several improvements made in procedures included a different method for stopband closure check and a positive method for postcoupler clamping. To obtain accurate results for the first tank a rigorous data ...
The XFEL and TTF facilities are planning to use section with a few third harmonic cavities (3.9GHz) upstream of the bunch compressor to improve beam performance [1-2]. Fermilab is developing superconducting third harmonic section for the TTFII upgrade. This section will include four cavities equipped with couplers and blade tuners ...
The SSC Low-Energy Booster (LEB) cavity must rapidly tune from 47.52 to 59.78 MHz. The cavity tuner will use transversely biased ferrite control of the cavity resonance. The thermal expansion of a cavity's materials affects its resonance. There are two ot...
Eddy currents are developed in the tuner of the Superconducting Super Collider Low Energy Booster (LEB) cavity during the LEB frequency sweep. The two main difficulties created by the eddy currents are excessive tuner-surface heating, and more important, a reduction in the time response of the tuner. We present a ...
A 100MeV proton accelerator is under development for the Proton Engineering Frontier Project (PEFP). The goal of the first stage of the project is to develop a 20MeV accelerator and the initial test of the 20MeV accelerator will be made. The DTL of 20 MeV accelerator consists of four tanks and will be driven with ...
The Tera-eV Energy Superconducting Linear Accelerator (TESLA), a 32 km long superconducting linear electron/positron collider of 500 GeV (upgradeable to 800 GeV) centre of mass energy, presently in the planning phase at DESY, will consist of about 21000 superconducting RF 9-cell cavities of pure Niobium. Each cavity of about 1 m length ...
The Thomas Jefferson National Accelerator Facility has begun a cryomodule refurbishment project. The goal of this project is robust 6 GeV, 5 pass operation of the Continuous Electron Beam Accelerator Facility (CEBAF). The scope of the project includes removing, refurbishing and replacing 10 CEBAF cryomodules at a rate of three per year. Refurbishment ...
The Thomas Jefferson National Accelerator Facility is currently engaged in a cryomodule refurbishment project known as the C50 project. The goal of this project is robust 6 GeV, 5 pass operation of the Continuous Electron Beam Accelerator Facility (CEBAF). The scope of the project includes removing, refurbishing and replacing ten CEBAF cryomodules at a ...
A coupled cavity accelerator (CCA) accelerates a charged particle beam with rf energy from a rf source. An input accelerating cavity receives the charged particle beam and an output accelerating cavity outputs the charged particle beam at an increased ...
The fundamental mode frequency of the prototype storage ring cavity has been measured with various port terminations and cavity temperatures. Since the highest tuned frequency of the prototype cavity with a tuner under the high RF power test condition is measured to be lower than the system specified frequency, a ...
A novel prototype of SCRF cavity tuner is being designed and tested at Fermilab. This is a superconducting C-type iron dominated magnet having a 10 mm gap, axial symmetry, and a 1 Tesla field. Inside the gap is mounted a superconducting coil capable of moving {+-} 1 mm and producing a longitudinal force up to {+-} 1.5 kN. The static force applied to the RF ...
The technology for mechanically compensating Lorentz Force detuning in superconducting RF cavities has already been developed at DESY. One technique is based on commercial piezoelectric actuators and was successfully demonstrated on TESLA cavities [1]. Piezo actuators for fast tuners can operate in a frequency range up to several kHz; ...
When complete, the Continuous Electron Beam Accelerator Facility will house a 4 GeV recirculating linear accelerator containing 42 1/4 cryomodules arrayed in two antiparallel linacs and an injector. Currently, 38 1/4 cryomodules have been installed. Each cryomodule contains eight superconducting niobium 5-cell rf cavities that operate ...
... Title : Resonant Frequencies of an Electromagnetic Cavity in an Accelerated System of Reference. Descriptive Note : Journal article,. ...
Three-stub WR650 waveguide tuners have been used on the CEBAF superconducting cavities for two changes of the external quality factors (Qext): increasing the Qext from 3.4-7.6 x 10{sup 6} to 8 x 10{sup 6}6 on 5-cell cavities to reduce klystron power at operating gradients and decreasing the Qext from 1.7-2.4 x 10{sup 7} to 8 x 10{sup ...
A novel ferroelectric frequency tuner was developed by the Ornega-P company and was tested at the Brookhaven National Laboratory on a 1.3 GHz RF cavity at room temperature. The tuner is based on the ferroelectric property of having a permittivity variable with an applied electric field. The achievable frequency tuning range can be ...
This paper presents the results of cw RF frequency control and RF phase-stabilization experiments performed with a piezoelectric fast tuner mechanically coupled to a superconducting, 345 MHz, {beta} = 0.5 triple-spoke-loaded cavity operating at 4.2K. The piezoelectric fast tuner damped low-frequency microphonic-noise by an order of ...
This paper presents the results of cw RF frequency control and RF phase-stabilization experiments performed with a piezoelectric fast tuner mechanically coupled to a superconducting, 345 MHz, � = 0.5 triple-spoke-loaded cavity operating at 4.2K. The piezoelectric fast tuner damped low-frequency microphonic-noise by an order of ...
A method is proposed for using adjustable, waveguide stub-line tuners to match the load impedance of the cavity plus beam to the power source, without the need to detune the cavity. Adjustable stub-line tuners are shown to be able to completely match the resistive and reactive parts of the load impedance to a ...
The beam excited 56 MHz SRF cavity will have a power coupler for a fast frequency tuner. The calculation shows the coupling of the power coupler, {beta}{sub opt}, is around 50. Size and location of the power coupler are determined by measurements. Measurements are in good agreement with the simulation results. The axial location of the power coupler for ...
The Spallation Neutron Source (SNS) is an accelerator-based neutron scattering research facility. The linear accelerator (linac) is the principal accelerating structure and divided into a room-temperature linac and a superconducting linac. The normal conducting linac system that consists of a Drift Tube Linac (DTL) and a Coupled ...
automatic method for tracking the cavity resonance and impedance match would ... ac motor driving an eccentric crank on its shaft to modulate the stub tuner ...
NASA Website
Recently remarkable progress has been achieved in the development of perpendicular biased ferrite tuned rf resonators for fast cycled synchrotrons. Compared with the broadly used parallel biased rf cavities they provide higher resonator quality factor Q. ...
The QKH1707 program concerned the design of a prototype ferrite-tuned, Ku-band coaxial magnetron. The tuner developed for this program is a ferrite-loaded, variable-reactance transmission line coupled to the coaxial cavity of the magnetron. The propagatio...
... Ile etc, A hydrogen maser ri th cavity auto- tuner for time keeping, to be publiehed in the proc of 23rd PTTI meeting, 1991, Page 6. STORAGE BULB ...
This report discusses the analysis and design of rf cavities and rf power sources in accelerators. (LSP).
... Title : ACCELERATOR-BUNCHER OF ELECTRONS,. ... CAVITY RESONATORS, KLYSTRONS, ELECTRON BEAMS, OSCILLATION, ELECTRON ...
The CEBAF Accelerator at Jefferson Lab is presently a 6 GeV five pass electron accelerator consisting of two superconducting linacs joined by independent magnetic transport arcs. Energy will be upgraded to 12 GeV with the addition of 10 new high gradient cryomodules (17+ MV/m). The higher gradients pose significant challenges beyond what the present analog ...
The design of the ALS storage ring 500 MHz cavity has been modeled with Mafia and Urmel codes. The effects of the holes cut for the drive port, the higher order mode damping port, the probe port and tuner plunger were modeled with the Mafia codes. The frequency dependence on the shape and spacing of the nose cones and the general shape of the ...
The operation of the major components used for controlling the phase and field level of the PEP RF cavities is described. The control electronics of one RF station is composed of several control loops: each cavity has a tuners' servo loop which maintains the frequency constant and also keeps the fields of each ...
A brief study was conducted to roughly estimate the availability of a superconducting (SC) linear accelerator (LINAC) as compared to a normal conducting (NC) one. Potentially, SC radio frequency cavities have substantial reserve capability, which allows them to compensate for failed cavities, thus increasing the availability of the ...
The cavities for the dual frequency system of the APS PAR are described. The system uses two frequencies: a 9.78MHz fundamental system for the particle accumulation and a 117.3MHz twelfth harmonic system for the bunch compression. The cavities have been built, installed, tested, and used for storing the beam in the PAR for about a year. The fundamental ...
This paper presents the results of tuning the 8 meter long Radio Frequency Quadrupole (RFQ) built for the Low Energy Demonstration Accelerator (LEDA). This 350-MHz RFQ is split into four 2-meter-long-RFQs. Then they are joined with resonant coupling to form an 8-meter-long RFQ. This improves both the longitudinal stability and the transverse stability of this long RFQ. The ...
Recent results on electron loading in superconducting cavities are presented and are compared with observations in dc field emission.
An active tuning method for rf cavities for accelerators is investigated. First tests of the method at low power levels are reported.
Numerous computer programs are available to help accelerator physicists and engineers model and design accelerator cavities and other microwave components. This article discusses the problems these programs solve and the principles upon which these programs are based. Some examples of how these programs are used in the design of ...
It is proposed to upgrade the Advanced Light Source by the addition of an RF system at the third-harmonic (1.5 GHz), of the existing system. With the new system it will be possible to control the bunch length and charge density profile independently of the RF bucket height, improving the Touschek-dominated beam lifetime. A third-harmonic cavity design is described which has ...
A new superconducting RF cavity test facility has been commissioned at Fermilab in conjunction with first tests of a 325 MHz, {beta} = 0.22 superconducting single-spoke cavity dressed with a helium jacket and prototype tuner. The facility is described and results of full gradient, CW cavity tests with a high Q{sub ...
The prototype cryomodule Renascence was constructed as an energy building block for securing 6 GeV operation of CEBAF and to validate design elements for future CEBAF upgrade modules. These elements include the new �HG� and �LL� 7-cell cavity designs and a new tuner design.[1,2] Issues were identified during initial testing in 2005. The module has ...
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 cavit...
Improvement in voltage regulation in a Linear Induction Accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating ...
The objective of this report was to create a low-cost, modest-power RF coupler for a SRF spoke cavity beam test of electrons test to be done at LANL. Developing the design for this magnetically-coupled SRF spoke cavity testing coupler was basically straightforward since the cavity coupling port needed to be one of the 1.22-inch ID ...
... warfare, joint planning, national and international ... of disk-loaded accelerator structure three ... Descriptors : (*PARTICLE ACCELERATORS, CAVITY ...
... ACCELERATION, RESISTANCE, ENERGY, NUMERICAL ANALYSIS, CAVITIES, FREE ELECTRONS, ELECTRON ENERGY, PUMPING ...
Energen, Inc. has developed and demonstrated an SRF cavity tuning mechanism based on magnetic smart materials. Magnetic ''smart'' materials change their shape in a reversible and repeatable manner when exposed to a small magnetic field. A fine-tuning mechanism with a 2 kHz tuning range on a nominal resonant frequency of 1.497 GHz. was ...
In the PSR's short-bunch operating mode, accumulated beam currents are intense and change rapidly. The resonant frequency of the 503.125-MHz buncher used in this mode must be rapidly adjusted through a 100-kHz range to maintain the correct 90/sup 0/ phase relation between cavity voltage and beam current. Modulation rates are up to 3 kHz/..mu..s. Each structure ...
The APS storage ring cavity is a single cell semi-spherical structure patterned along the lines of the KEK Photon Factory and the Daresbury cavities. The cavity was initially scaled to the APS frequency of 352.9 MHz using the computer code URMEL. Before construction of the prototype, it was considered essential to simulate the ...
The 1.6 cell S-band photoinjector cavity has been in operation at the DUVFEL at BNL for the past year. Initial beam measurements indicated a higher than expected emittance and beam divergence at the exit of the gun. field imbalance in the two cells was suspected, but lack of field probes in the cavity prohibited direct confirmation. A detailed SUPERFISH ...
A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of accelerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second ...
Experiences are reported of welding niobium to stainless steel for the TESLA accelerator superconducting cavities.
The acceleration structure chosen for the Saturne is the inductive cavity with the variation of the tuning frequency obtantned by saturation of the ferrite core of the cavity by means of a current which increases along the cycle and by decrease of the capacity of an auxiliary condenser at the edge of the ...
Omega3P is a parallel eigenmode calculation code for accelerator cavities in frequency domain analysis using finite-element methods. In this report, we will present detailed finite-element formulations and resulting eigenvalue problems for lossless cavities, cavities with lossy materials, ...
This report describes a ferrite tuner design for the LEB cavity that utilizes techniques for bonding ferrite to metallic cooling plates that is utilized in the high-power rf and microwave industry. A test tuner was designed to fit into the existing LEB-built magnet and onto the Grimm LEB Cavity. It will require a ...
... On the design of beam absorbers for the SSC - Brett Parker ... Design of an accelerating cavity for the Superconducting Super Collider Low-Energy ...
... a recirculating accelerator known as the Spiral Line Induction Accelerator (SLIA ... is not unlike other long pulse recirculating accelerators where beam ...
The ILC crab cavity will require the design of an appropriate power coupler. The beam-loading in dipole-mode cavities is considerably more variable than accelerating cavities, hence simulations have been performed to establish the required external Q. Sim...
Accelerator systems are being built with superconducting Nb cavities at 350, 500, 1500 and 2860 MHz; in addition cavities previously have been built at 1000 MHz. Cavity heat loads are a strong function of frequency and operating temperature, varying by more than an order of magnitude.
A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of ...
