ANL, Lemont, Illinois, USA
Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357
ANL, Lemont, Illinois, USA
Argonne Wakefield Accelerator (AWA) group demonstrated arbitrary longitudinal shaping capability of thee emittance exchange (EEX) beamline in 2016. Several different transverse masks were used to shape the beam transversely, and the transmission through the mask was around 40%. The masking is one of the easiest ways to control the profile, but this low transmission would make significant drop of the beam quality due to a higher charge requirement in the gun, and it can make thermal issues for high repetition rate or high intensity beams. At the same time, it only controls the profile not a 2D phase space. We recently proposed a scheme to generate a tunable bunch train using a EEX beamline with a transverse wiggler. This wiggler provides a sinusoidal magnetic field which makes a sinusoidal modulation on the transverse phase space. If the beam passes series of transverse wigglers with different period and strength, one can make arbitrary correlation on the horizontal position and momentum. It opens up totally new way to control all longitudinal properties including arbitrary current profile shaping without charge loss. In this poster, we present the concept of the work and plan.
BNL, Upton, New York, USA
The NSLS-II Active Interlock is the system which protects the NSLS-II Storage Ring vacuum chamber from damage due to synchrotron radiation. The Active Interlock measures the beam position and angle at all insertion devices and issues a beam dump if the beam is outside of the pre-defined window. The window is determined by thermal analysis of vacuum apertures and considers the effects of local magnets such as canting magnets, etc. Recently, it was realized that the insertion device correction coils where not considered in the initial evaluation of the envelope. The purpose of these coils is to correct for the orbit deviations caused by imperfections in the insertion devices that steer the beam. The usual effect is to negate any angle induced by the device, however, if the coil is not set properly the beam may have a larger angle than permitted by the Active Interlock even though the angle calculation does not show it. In this paper we discuss the effect of the insertion device coils on the electron beam and the steps taken to account for this effect in the Active Interlock.
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
The Cornell Electron Storage Ring (CESR) was upgraded in the second half of 2018 to become a dedicated synchrotron light source, CHESS-U. The upgrade is by far the largest modification to CESR in its 40-year history, replacing one-sixth of the storage ring with six new double-bend achromats, increasing beam energy from 5.3 GeV to 6.0 GeV, and switching from two counter-rotating beams to a single on-axis positron beam. The new achromats include combined-function dipoles, a first in CESR, and reduce the horizontal emittance by a factor of four. Eight compact narrow-gap undulators (4.6mm vacuum chamber aperture) and one high-energy 24-pole wiggler feed a total of six new and five existing x-ray end stations from a single positron beam. Commissioning of CHESS-U took place in the first half of 2019. We report on the methods and results of beam commissioning, including initial beam accumulation, optics correction, characterization, and commissioning of compact permanent-magnet insertion devices.
University of Chicago, Chicago, Illinois, USA
SLAC, Menlo Park, California, USA
ANL, Lemont, Illinois, USA
Fermilab, Batavia, Illinois, USA
RadiaBeam, Marina del Rey, California, USA
BNL, Upton, New York, USA
ANL, Lemont, Illinois, USA
UNIST, Ulsan, Republic of Korea
Emittance exchange (EEX) provides a powerful method of controlling the longitudinal phase space using the relatively simpler methods of transverse control. An EEX beamline was installed at the Argonne Wakefield Accelerator (AWA) facility in 2015. Several experiments important to the wakefield acceleration, such as a high transformer ratio from shaped bunches, have already been demonstrated. We are currently developing several applications of the EEX beamline including temporal profile shaping, THz radiation generation, time-energy correlation control, diagnostic uses of EEX etc. We will present the on-going EEX program for longitudinal phase space control taking place at the AWA facility, and discuss recently discovered new opportunities.