ANL, Argonne, Illinois, USA
APS Upgrade (APS-U) will feature hybrid seven-bend achromat lattice with very strong focusing elements and relatively small vacuum chamber aperture. Achieving design lattice parameters during commissioning will need to be accomplished quickly in order to minimize dark time for APS users. The paper will describe the automated start-to-end lattice commissioning algorithm starting with the first-turn trajectory correction and ending with the lattice correction. It will then show simulation results of the APS-U commissioning, and finally present results of the experimental tests of the commissioning at the existing APS.
ANL, Argonne, Illinois, USA
APS Upgrade will feature an entirely new storage ring but will keep the existing injector complex consisting of the linear accelerator, Particle Accumulator Ring (PAR) and Booster. Due to small dynamic aperture of the APS Upgrade lattice, swap-out injection is adapted when an entire old bunch is replaced with a new bunch. This injection requires Booster to provide high-charge bunches with up to 17 nC in a single bunch. An extensive work is being carried out on characterizing the existing injector rings to ensure future high-charge operation. In this paper, we will present results of the lattice measurement using the response matrix fit. We will show the analysis of the achievable lattice measurement accuracy in the APS Booster and describe fit parameter modifications required to achieve good fit accuracy for the PAR.
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.
ANL, Argonne, Illinois, USA
A helical superconducting undulator (HSCU) was installed in the Advanced Photon Source (APS) Storage Ring (SR) during the January 2018 maintenance period. Shortly after the reintroduction of beam into the SR in late January, higher than expected heating was observed in the cryogenic cooling system. Steering the electron beam orbit in the upstream dipole provided reduction of the amount of synchrotron radiation reaching into the HSCU and allowed the device to properly cool and operate. Modeling the HSCU geometry with MARS shows the importance of Compton Scattering in transferring synchrotron photons with energies in the range of 10-100 keV through the vacuum chamber into the HSCU magnet pole and winding regions. Simulations carried out using MARS with EGS5 enabled indicate a rapid increase in transfer efficiency from the chamber wall to the HSCU with photon energy. Realistic spectral distributions of synchrotron photons are employed as input to MARS for several bending magnet field strengths.