ANL, Lemont, Illinois, USA
Euclid TechLabs, Solon, Ohio, USA
Euclid Beamlabs, Bolingbrook, USA
Northern Illinois University, DeKalb, Illinois, USA
A program is under way at the Argonne Wakefield Accelerator facility, in collaboration with the Euclid Techlabs and Northern Illinois University (NIU), to develop a GeV/m scale photocathode gun, with the ultimate goal of demonstrating a high-brightness photoinjector beamline. The novel X-band photoemission gun (Xgun) is powered by high-power, short RF pulses, 9-ns (FWHM), which, in turn, are generated by the AWA drive beam. In a previous proof-of-principle experiment, an unprecedented 400~MV/m gradient on the photocathode surface* was demonstrated. In the current version of the experiment, we added a linac to the beamline to increase the total energy and gain experience tuning the beamline. In this paper, we report on the very first result of emittance measurement as well as several other beam parameters. This preliminary investigation has identified several factors to be improved on in order to achieve one of the ultimate goals; low emittance.
* W. H. Tan et al., "Demonstration of sub-GV/m Accelerating Field in a Photoemission Electron Gun Powered by Nanosecond X-Band Radiofrequency Pulses", 2022. arXiv:2203.11598v1
Northern Illinois University, DeKalb, Illinois, USA
JLab, Newport News, Virginia, USA
ANL, Lemont, Illinois, USA
LBNL, Berkeley, California, USA
Beamlines capable of merging beams with different energies are critical to many applications related to advanced accelerator concepts and energy-recovery linacs (ERLs). In an ERL, a low-energy "fresh" bright bunch is generally injected into a superconducting linac for acceleration using the fields established by a decelerated "spent" beam traveling on the same axis. A straight-merger system composed of a selecting cavity with a superimposed dipole magnet was proposed and recently test at AWA. This paper reports on the experimental results obtained so far along with detailed beam dynamics investigations of the merger concept and its ability to conserve the beam brightness associated with the fresh bunch.
ANL, Lemont, Illinois, USA
IIT, Chicago, Illinois, USA
A single-pulse, high dynamic range, cost-effective BPM signal detector has been on the most wanted list of the Argonne Wakefield Accelerator (AWA) Test Facility for many years. The unique capabilities of the AWA beamline require BPM instrumentation with an unprecedented dynamic range, thus a cost-effective solution could be challenging to design and prototype. With the help of a better circuit model for a button BPM signal source, we are able to do the circuit simulations with more realistic input signals and make predictions much closer to realities. Our most recent design and prototype results are shared in this paper.
UCLA, Los Angeles, California, USA
ANL, Lemont, Illinois, USA
By shaping the transverse profile of a particle beam prior to an emittance exchange (EEX) beamline, drive and witness beams with variable current profiles and bunch spacing can be produced. Presently at AWA, this transverse shaping is accomplished with individually laser-cut tungsten masks, making the refinement of beam profiles a slow process. In contrast, a multileaf collimator (MLC) is a device that can selectively mask the profile of a beam using many independently actuated leaves. Since an MLC permits real-time adjustment of the beam shape, its use as a beam mask would permit much faster optimization in a manner highly synergistic with machine learning. Beam dynamics simulations have shown that such an approach is functionally equivalent to that offered by the laser cut masks. In this work, the construction and first results from a 40-leaf, UHV compatible MLC are discussed.