Fermilab, Batavia, USA
Yale University, Physics Department, New Haven, CT, USA
Euclid TechLabs, LLC, Solon, Ohio, USA
Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
* A. Kanareykin, et al, IPAC 2010, p. 3987
** S. Kazakov, et al, “Fast Ferroelectric Phase Shifter Design For ERLs,” 45th ICFA Beam Dynamics Workshop, 2009
*** S. Kazakov, et al, PAC2007, p. 599.
Muons, Inc, Batavia, USA
ANL, Argonne, USA
Tomco Technologies, Stepney, South Australia, Australia
Siemens AG, Erlangen, Germany
Siemens AG, Healthcare Technology and Concepts, Erlangen, Germany
* Heid O., Hughes T. THPD002, IPAC10, Kyoto, Japan
** Hergt M et al, 2010 IEEE International Power Modulator and High Voltage Conf., Atlanta GA, USA
*** Heid O., Hughes T. THP068, LINAC10, Tsukuba, Japan
ANL, Argonne, USA
Development and testing of a prototype 352-MHz, 4-kW cw solid state rf power amplifier system is underway at the Advanced Photon Source to study and evaluate the performance advantages of an upgrade to solid state rf power technology at the APS. General performance measurement data on the assembled amplifier system is discussed, with emphasis on efficiency improvements possible through the use of dynamic drain voltage control.
BNL, Upton, Long Island, New York, USA
CCR, San Mateo, California, USA
Calabazas Creek Research Inc. (CCR) is developing a 100 kW CW, 2.815 GHz klystron for use in the Advanced Photon Source upgrade light source at Argonne National Laboratory. Periodic permanent magnet (PPM) focusing is used to avoid loss in efficiency due to the power normally required for a solenoid. The PPM structure elements consist of 4 disk (pill box) magnets with a clover-leaf shaped iron pole piece. The gaps between the magnets permit the introduction of liquid cooling into the RF circuit. Design tools include the large signal codes KLSC and TESLA for the efficiency calculations, MAXWELL 3D for the magnetic fields, and the CCR 3D code BOA for the beam trajectories. From initial simulations with seven cavities, the efficiency will be over 62% with a beam voltage of 47 kV. The saturated gain is 44 dB. The design emphasizes high reliability, with simple construction, robust cooling and low thermal loading through high efficiency. The paper will include the details of the design, including results of the simulations of the RF and magnetic structures, beam trajectories, and thermo-mechanical analyses.
CCR, San Mateo, California, USA
SAIC, McLean, USA
Calabazas Creek Research Inc. (CCR) is developing a pulsed 140 kW, 402.5 MHz Inductive Output Tube (IOT) for use in proton accelerators. Unlike other high power multiple-beam IOT's currently under development, this device will use a single electron beam, and will be less expensive and have a higher reliability. The program includes the use of new design tools, including NEMESIS and a version of CCR's 3D Beam Optics Analysis (BOA) code modified to include time dependent modeling. The design will include the electron gun, collector, input and output cavities, input and output couplers and the RF output window. An emphasis will be placed on the electron gun, which will as usual include a grid for the high frequency modulation, and the input cavity. The new version of BOA is expected to be particularly useful in modeling the formation of the bunched beam and will replace the relatively slow 3D PIC code MAGIC as the primary design tool. HFSS and NEMESIS will be used for design of the input cavity. The paper will include details of the design.
DULY Research Inc., Rancho Palos Verdes, California, USA
Tunable couplers for adjusting radiofrequency (RF) power coupling into accelerator cavities are useful devices for achieving optimal operation efficiency. Standard mechanical tuners currently used in large accelerator facilities are bulky and complicated. A novel tuner, based on the introduction of dielectric tubes or fluid-filled volumes adjacent to, but separated by window(s) from the coupler, is described. Simulations have shown that the tuner has a fairly large adjustment range and also demonstrated the viability of the tuning concept using fluid circuit.
Fermilab, Batavia, USA
For Project X Fermilab Main Injector will be required to provide up to 2.3 MW to a neutrino production target at energies between 60 and 120 GeV. To accomplish the above power levels 3 times the current beam intensity will need to be accelerated. In addition the injection energy of Main Injector will need to be as low as 6 GeV. The current 30 year old Main Injector radio frequency system will not be able to provide the required power and a new system will be required. The specifications of the new system will be described.
LLNL, Livermore, California, USA
SLAC, Menlo Park, California, USA
In support of x-band photoinjector development efforts at LLNL, a 50 MW test station is being constructed to investigate structure and photocathode optimization for future upgrades. A SLAC XL-4 klystron capable of generating 50 MW, 1.5 microsecond pulses will be the high power RF source for the system. The timing of the laser pulse on the photocathode with the applied RF field places very stringent requirements on phase jitter and drift. To achieve these requirements, the klystron will be powered by a state of the art, solid-state, high voltage modulator. The 50 MW of RF power will be divided between the photoinjector and a traveling wave accelerator section. A high power phase shifter is located between the photoinjector and accelerator section to adjust the phasing of the electron bunches with respect to the accelerating field. A variable attenuator is included on the input of the photoinjector. The distribution system including the various x-band components is being designed and constructed. In this paper, we will present the design, layout, and status of the RF system.
LANL, Los Alamos, New Mexico, USA
Compa Industries, Inc., Los Alamos, New Mexico, USA
A Full-scale prototype of a new 201 MHz RF Final Power Amplifier (FPA) for Los Alamos Neutron Science Center (LANSCE) has been designed, fabricated, assembled and installed in the test facility. This prototype was successfully tested and met the physics and electronics design criteria. With a goal to produce 3.2 MW peak power at 15% duty factor, at the elevation of over 2 km in Los Alamos, The team faced design and manufacturing challenges. The mechanical design of the final power amplifier was built around a Thales TH628 Diacrode®, a state-of-art tetrode power tube*. The main structure includes Input circuit, Output circuit, Grid decoupling circuit, Output coupler, Tuning pistons, and a cooling system. Many kinds of material were utilized to make this new RF amplifier. The FPA is nearly 1000 kg and installed in a beam structural support stand. In this paper, we summarize the FPA design basis and fabrication, plating, and assembly process steps with necessary lifting and handling fixtures. In addition, to ensure the quality of the FPA support structure a finite element analysis with seismic design forces has also been carried out.
* J. Lyles, S. Archuletta, N. Bultman, Z. Chen, et al., “Design of a New VHF RF Power Amplifier System for LANSCE”, IPAC’10, Kyoto, Japan, May 24-28, 2010.
LANL, Los Alamos, New Mexico, USA
Compa Industries, Inc., Los Alamos, New Mexico, USA
Texas A&M University, College Station, Texas, USA
A new test facility was designed and constructed at Los Alamos Neutron Science Center (LANSCE) for testing the Thales TH628 Diacrode® and TH781 tetrode power amplifiers. Anode power requirements for the TH628 are 28 kV DC, with peak currents of 190 Amperes in long pulses. A new 225 uF capacitor bank supplies this demand. A charging power supply was obtained by re-configuring a 2 MW beam power supply remaining from another project. A traditional ignitron crowbar was designed to rapidly discharge the 88 kJ stored energy. The anode power supply was extensively tested using a pulsed tetrode switch and resistor load. A new Fast Protect and Monitor System (FPMS) was designed to take samples of RF reflected power, anode HV, and various tube currents, with outputs to quench the HV charging supply, remove RF drive and disable the conduction bias pulse to the grid of each tube during fault events. The entire test stand is controlled with a programmable logic controller, for normal startup sequencing and timing, protection against loss of cooling, and operator GUI.
LANL, Los Alamos, New Mexico, USA
Compa Industries, Inc., Los Alamos, New Mexico, USA
Texas A&M University, College Station, Texas, USA
A prototype VHF RF Final Power Amplifier (FPA) for Los Alamos Neutron Science Center (LANSCE) has been designed, fabricated, and tested. The cavity amplifier met the design goals producing 3.2 MW peak and 480 kW of average power, at an elevation of 2.1 km. It was designed to use a Thales TH628 Diacrode®, a state-of-art tetrode power tube that is double-ended, providing roughly twice the power of a conventional tetrode. The amplifier is designed with tunable input and output transmission line cavity circuits, a grid decoupling circuit, an adjustable output coupler, TE mode suppressors, blocking, bypassing and decoupling capacitors, and a cooling system. The tube is connected in a full wavelength output circuit, with the lower main tuner situated ¾λ from the central electron beam region in the tube and the upper slave tuner ¼λ from the same point. We summarize the design processes and features of the FPA along with significant test results. A pair of production amplifiers are planned to be power-combined and installed at the LANSCE DTL to return operation to full beam duty factor.
SLAC, Menlo Park, California, USA
University of Iowa, Iowa City, Iowa, USA
ANL, Argonne, USA
Currently, power to the APS storage ring and Booster cavities is provided from klystrons with a eventual goal to move to a solid state RF system. A modular design centered around a 1 kW amplifier has been decided on. The driver amplifier was created for this module system using Agilent’s ADS circuit simulation software and then built and tested.
SLAC, Menlo Park, California, USA
The input power of accelerator structure is normally fed through a coupling slot(s) on the outer wall of the accelerator structure via magnetic coupling. While providing perfect matching, the coupling slots may produce non-axial-symmetric fields in the coupler cell that can induce emittance growth as the beam is accelerated in such a field. This effect is especially important for low emittance beams at low energies such as in the injector accelerators for light sources. In this paper, we present studies of multipole fields of different rf coupler designs and their effect on beam emittance for an X-band photocathode gun, being jointly designed with LLNL, and the X-band accelerator structures. We will present symmetrized rf coupler designs for these components to preserve the beam emittance.
Siemens AG, Healthcare Technology and Concepts, Erlangen, Germany
Siemens AG, Erlangen, Germany
* Heid O., Hughes T. THPD002, IPAC10, Kyoto, Japan
** Hergt M et al, 2010 IEEE International Power Modulator and High Voltage Conf., Atlanta GA, USA
*** Heid O., Hughes T. THP068, LINAC10, Tsukuba, Japan
ORNL, Oak Ridge, Tennessee, USA
ORNL RAD, Oak Ridge, Tennessee, USA
JLAB, Newport News, Virginia, USA
Jefferson Laboratory (JLab) is currently upgrading the 6GeV Continuous Electron Beam Accelerator Facility (CEBAF) to 12GeV. As part of the upgrade, RF systems will be added, bringing the total from 340 to 420. Existing RF systems can provide up to 6.5 kW of CW RF at 1497 MHZ. The 80 new systems will provide increased RF power of up to 13 kW CW each. Built around a newly designed and higher efficiency 13 kW klystron developed for JLab by L-3 Communications, each new RF chain is a completely revamped system using hardware different than our present installations. This paper will discuss the main components of the new systems including the 13 kW klystron, waveguide isolator, and HV power supply using switch-mode technology. Methodology for selection of the various components and results of initial testing will also be addressed.
FROBS2
HZB, Berlin, Germany