ANL, Argonne, Illinois, USA
Three s-band RF guns are installed at the front end of the Advanced Photon Source (APS) linac: two thermionic cathode guns (RG2 and RG1), and one Photo-Cathode Gun (PCG). During normal operations, RG2 provides electron beams for the storage ring to generate x-rays for APS users. The PCG generates high brightness electron beams that can be accelerated through the APS linac and transported into the Linac Extension Area (LEA) for advanced accelerator technology and beam physics experiments. The alternating acceleration of the RG2 and PCG beam in the linac is possible, as most of the time, RG2 beam is only needed for ~20 seconds every two minutes. This mode of interleaving operation of RG2 and PCG beams through the APS linac requires some modifications/additions to several systems of the linac, including RF, magnets, controls and Access Control Interlock System etc. In this paper we report our interleaving design and present the commissioning results of the two beam interleaving operation.
TUWPLS1
ANL, Argonne, Illinois, USA
An electron beam obtained directly out of an injector does not always have the phase-space properties required for its optimum use. Phase-space manipulation is often necessary to achieve certain beam distributions in the transverse and longitudinal dimensions. There are many ways to accomplish the control of transverse beam profile such as using focusing magnets or shaping masks, and re-partition of the transverse phase-spaces. In comparison, less resources are available to arbitrarily shape the longitudinal distribution directly. However, owing to the transverse-to-longitudinal emittance exchange technique first demonstrated at the Fermilab A0 Photo-injector, the longitudinal beam profiles can be obtained by first shaping the beam transversely, followed by mapping the transverse distribution into longitudinal. Longitudinal beam profile manipulation via EEX has been greatly advanced at the Argonne Wakefield Accelerator and precise tailoring for various longitudinal beam profiles has been achieved. In this talk we will present the progress on beam shaping via 6D phase-space manipulation and discuss future research in the area.
RadiaBeam, Santa Monica, California, USA
ANL, Argonne, Illinois, USA
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 for the Advanced Photon Source at Argonne National Laboratory, which would offer substantial improvements in reliable operations with a robust interface between the thermionic cathode and the cavity, as well as better RF performance, compared to existing models. This improvement became possible by incorporating new pi-mode electromagnetic design, robust cavity back plate design, and a cooling system that will allow stable operation for up to 1 A of beam current and 100 Hz rep rate at 1.5 μs RF pulse length, and 70 MV/m peak on-axis field in the cavity. In this paper, we discuss the electromagnetic and engineering design of the cavity and provide the test results of the new gun.
ANL, Argonne, Illinois, USA
BNL, Upton, Long Island, New York, USA
Fermilab, Batavia, Illinois, USA
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 the ring with high single-bunch charge for swap-out. For upgrades of existing light sources, such as the Advanced Photon Source Upgrade (APS-U), it is economical to retain the existing injector infrastructure and make appropriate improvements. The challenges to these improvements include achieving high single-bunch charge in the presence of instabilities, beam loading, charge stability and reliability. In this paper, we discuss the rationale for the injector upgrades chosen for APS-U, as well as backup and potential alternate schemes. To date, we have achieved single-bunch charge from the injectors that doubles the original design value, and have a goal to achieve about three times the original design value.