G. Waldschmidt
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View article: A high repetition rate millimeter wavelength accelerator for an X-ray free-electron laser
A high repetition rate millimeter wavelength accelerator for an X-ray free-electron laser Open
A compact collinear wakefield accelerator has been designed for an X-ray free-electron laser capable of operating at a pulse repetition rate in the tens of kilohertz. The maximum achievable accelerating gradient has been determined, with i…
View article: Fabrication and testing of the transition section between modules of a wakefield accelerator
Fabrication and testing of the transition section between modules of a wakefield accelerator Open
The fabrication process is presented for a typical transition section located between each cylindrical corrugated waveguide structure comprising the wakefield accelerator module. The transition section includes couplers for extracting the …
View article: Preserving restoring and conditioning the RF cavities of the storage ring for the Advanced Photon Source upgrade
Preserving restoring and conditioning the RF cavities of the storage ring for the Advanced Photon Source upgrade Open
The Advanced Photons Source (APS) storage ring (SR) underwent an upgrade to the multi-bend achromat (MBA) lattice recently. As part of the upgrade, four out of the sixteen Radio Frequency (RF) cavities were removed from the storage ring. T…
View article: Mode Damping Measurement for the APS Deflecting Cavity
Mode Damping Measurement for the APS Deflecting Cavity Open
The Advanced Photon Source has considered using a deflecting-cavity-based scheme to produce short pulse xrays. A deflecting cavity design has been completed. To verify the simulation result on this cavity, a copper prototype of the design …
View article: Tubular RF cage field confinement cavity
Tubular RF cage field confinement cavity Open
An RF cavity is provided with a plurality of tubes that are formed into a tubular cage in a predefined shape to define the RF cavity. A selected number of tubes and a selected tube diameter are provided to form a confinement cage for the R…
View article: Electromagnetic design of the transition section between modules of a wakefield accelerator
Electromagnetic design of the transition section between modules of a wakefield accelerator Open
The electromagnetic design of a transition section consisting of couplers for extracting the 180-GHz TM01 accelerating mode and 190-GHz HE11 dipole mode of a cylindrical corrugated waveguide used as a collinear wakefield accelerator is pre…
View article: Design of a cylindrical corrugated waveguide for a collinear wakefield accelerator
Design of a cylindrical corrugated waveguide for a collinear wakefield accelerator Open
We present the design of a cylindrical corrugated waveguide for use in the A-STAR accelerator under development at Argonne National Laboratory. A-STAR is a high gradient, high bunch repetition rate collinear wakefield accelerator that uses…
View article: Fabrication and testing of corrugated waveguides for a collinear wakefield accelerator
Fabrication and testing of corrugated waveguides for a collinear wakefield accelerator Open
Significant progress has been made at Argonne National Laboratory in the development of a compact wakefield accelerator based on a cylindrical corrugated waveguide with a 2-mm ID and fine corrugations on the wall. The fabrication process o…
View article: High-Power Prototype Canon Coupler for APS-U Booster Cavities
High-Power Prototype Canon Coupler for APS-U Booster Cavities Open
The Advanced Photon Source Upgrade (APS-U) plans to achieve a beam capture efficiency above 90% at 17 nC bunch charge into the Booster. Due to large beam loading at injection, the 352-MHz Booster cavities will be significantly detuned nece…
View article: 352-MHz Solid State RF System Development at the Advanced Photon Source
352-MHz Solid State RF System Development at the Advanced Photon Source Open
Development effort is underway on a 352MHz, 200kW solid state rf system intended as the base design to replace the existing klystron-based rf systems presently in use at the Advanced Photon Source (APS). A sixteen-input, 200kW final combin…
View article: Thermionic microwave gun for terahertz and synchrotron light sources
Thermionic microwave gun for terahertz and synchrotron light sources Open
Conventional thermionic microwave and radio frequency (RF) guns can offer high average beam current, which is important for synchrotron light and terahertz (THz) radiation source facilities, as well as for industrial applications. For exam…
View article: Microwave thermionic electron gun for synchrotron light sources
Microwave thermionic electron gun for synchrotron light sources Open
Thermionic RF guns are the source of electrons used in many practical applications, such as drivers for synchrotron light sources, preferred for their compactness and efficiency. RadiaBeam Systems has developed a new thermionic RF gun for …
View article: High-Charge Injector for on-Axis Injection Into A High-Performance Storage Ring Light Source
High-Charge Injector for on-Axis Injection Into A High-Performance Storage Ring Light Source Open
Next-generation, high-performance storage ring light sources based on multibend achromat optics will require on-axis injection because of the extremely small dynamic aperture. Injectors will need to supply full-current bunch replacement in…
View article: High-Power Design of a Cavity Combiner for a 352-MHz Solid State Amplifier System at the Advanced Photon Source
High-Power Design of a Cavity Combiner for a 352-MHz Solid State Amplifier System at the Advanced Photon Source Open
A cavity combiner has been designed as part of a solid state amplifier system at the Advanced Photon Source with a power requirement of up to 200 kW for the full system. Peak field levels and thermal loading have been optimized to enhance …
View article: Microwave Thermionic Electron Gun for Synchrotron Light Sources
Microwave Thermionic Electron Gun for Synchrotron Light Sources Open
Thermionic RF guns are the source of electrons used in many practical applications, such as drivers for synchrotron light sources, preferred for their compactness and efficiency. RadiaBeam Technologies has developed a new thermionic RF gun…
View article: Design and Testing of a 12 kW, 352 MHz Solid State rf System at the Advanced Photon Source
Design and Testing of a 12 kW, 352 MHz Solid State rf System at the Advanced Photon Source Open
A 12 kW, 352 MHz rf power amplifier system was designed and constructed at the Advanced Photon Source as a research and development test bed for eventual development of a 200 kW cw rf system capable of supporting accelerator beam operation…
View article: A Scheme for Asynchronous Operation of the APS-U Booster Synchrotron
A Scheme for Asynchronous Operation of the APS-U Booster Synchrotron Open
The APS-U 6-GeV MBA storage ring will have 42 pm beam emittance and relatively tight acceptance. This requires limiting the beam emittance out of the Booster synchrotron which is achieved by operating the Booster off-momentum, thus manipul…
View article: A Conceptual Design of a Compact Wakefield Accelerator for a High Repetition Rate Multi User X-ray Free-Electron Laser Facility
A Conceptual Design of a Compact Wakefield Accelerator for a High Repetition Rate Multi User X-ray Free-Electron Laser Facility Open
A preliminary design of a collinear wakefield accelerator is described. It is assumed that the array of such accelerators will play a central role in a free-electron laser-based x-ray user facility under consideration at Argonne National L…
View article: Design and Test Plan for a Prototype Corrugated Waveguide
Design and Test Plan for a Prototype Corrugated Waveguide Open
A cylindrical, corrugated wakefield accelerating structure with a 1 mm radius bore is being designed to facilitate sub-terahertz Čerenkov radiation produced by an elec-tron bunch propagating along the waveguide. A 220 GHz axial mode for th…
View article: Dynamic Tuning of the APS-U Booster 5-cell Cavities
Dynamic Tuning of the APS-U Booster 5-cell Cavities Open
The booster synchrotron for the APS-U is being upgraded to accommodate high-charge bunches, up to 20 nC, for extraction into the MBA lattice. The booster is required to operate at 85% efficiency in order to achieve bunch swap-out into the …
View article: Dielectrically-Loaded Waveguide as a Microwave Undulator for High Brillance X-Rays at 45 - 90 Kev
Dielectrically-Loaded Waveguide as a Microwave Undulator for High Brillance X-Rays at 45 - 90 Kev Open
The HEM12 mode in a cylindrical, dielectrically-loaded waveguide provides E and H fields on the central axis that are significantly higher than the fields on the conducting walls. This structure, operating near the cutoff frequency of the …
View article: Crab Cavity and Cryomodule Prototype Development for the Advanced Photon Source
Crab Cavity and Cryomodule Prototype Development for the Advanced Photon Source Open
We review the single-cell, superconducting crab cavity designs for the short-pulse x-ray (SPX) project at the Advanced Photon Source (APS). The 'on-cell' waveguide scheme is expected to have a more margin for the impedance budget…
View article: Transverse Cavity Tuning at the Advanced Photon Source
Transverse Cavity Tuning at the Advanced Photon Source Open
A 15-cell transverse deflecting cavity based on a SLAC design was fabricated at the Advanced Photon Source and is being prepared for installation into the Injector Test Stand. A beadpull method for tuning was selected in lieu of the nodal …
View article: Superconducting Harmonic Cavity for the Advanced Photon Source Upgrade
Superconducting Harmonic Cavity for the Advanced Photon Source Upgrade Open
A new bunch lengthening cryomodule using a single-cell ‘higher-harmonic’ superconducting cavity (HHC) based on the TESLA shape and operating at the 4th harmonic (1408 MHz) of the main RF is under development at Argonne. The system will be …
View article: Higher Order Mode Damping in a Higher Harmonic Cavity for the Advanced Photon Source Upgrade
Higher Order Mode Damping in a Higher Harmonic Cavity for the Advanced Photon Source Upgrade Open
A superconducting higher-harmonic cavity (HHC) is under development for the Advanced Photon Source Upgrade based on a Multi-Bend Achromat lattice. This cavity will be used to improve the Touschek lifetime and the single bunch current limit…