RadiaBeam, Santa Monica, California, USA
RadiaSoft LLC, Boulder, Colorado, USA
ANL, Lemont, Illinois, USA
UCLA, Los Angeles, California, USA
The plasma photocathode concept, whereby a two-species gas mixture is used to generate a beam -driven accelerating wakefield and a laser-ionized generation of a witness beam, was recently experimentally demonstrated. In a variation of this concept, a beam-driven dielectric wakefield accelerator is employed, filled with a neutral gas for laser-ionization and creation of a witness beam. The dielectric wakefields, in the terahertz regime, provide comparatively modest timing requirements for the injection phase of the witness beam. In this paper, we provide an update on the progress of the experimental realization of the hybrid dielectric wakefield accelerator with laser injected witness beam at the Argonne Wakefield Accelerator (AWA), including engineering considerations for gas delivery, and preliminary simulations.
Euclid TechLabs, Solon, Ohio, USA
SLAC, Menlo Park, California, USA
ANL, Lemont, Illinois, USA
A typical accelerating structure is a set of copper resonators brazed together. This multi step process is expensive and time consuming. In an effort to optimize production process for rapid prototyping and overall reduction of accelerator cost we developed a split block brazeless accelerating structure. In such structure the vacuum is sealed by the use of knife edges, similar to an industry standard conflat technology. In this paper we present high power tests of several different brazeless structures. First, an inexpensive 1 MeV accelerator powered by radar magnetron. Second, a high gradient power extractor tested at Argonne Wakefield Accelerator Facility. In this experiment a high charge electron beam generated a 180 MW peak power pulse. Finally, we report on high power testing of a brazeless x-band accelerating structure at SLAC.
MIT/PSFC, Cambridge, Massachusetts, USA
ANL, Lemont, Illinois, USA
Euclid TechLabs, Solon, Ohio, USA
Northern Illinois University, DeKalb, Illinois, USA
We present our recent results generating 510 MW of power at 11.7 GHz using a metamaterial-based metallic power-extractor for application in structure-based wakefield acceleration (SWFA). SWFA is a novel acceleration scheme in which high-charge electron bunches are passed through a power extractor structure to produce a high-intensity wakefield. This wakefield can then be used to accelerate a witness bunch in the same beamline or passed to a separate acceleration beamline. MIT’s approach uses a specialized metamaterial for the power extractor design. By using a metamaterial, we can overcome some of the challenges faced by other SWFA techniques. Here, we discuss the Stage 3 experiment. The Stage 1 and Stage 2 experiments successfully demonstrated the functionality of the metamaterial approach by generating high power RF pulses using the 65 MeV electron beam at the Argonne Wakefield Accelerator (AWA) facility. The 510 MW result from Stage 3 experiment is the highest power generated to-date for SWFA at AWA, and was enable by significant design improvements, including an all-copper structure, fully-symmetric coupler design, and breakdown risk-reduction treatment.
Northern Illinois University, DeKalb, Illinois, USA
ANL, Lemont, Illinois, USA
Single pulse high dynamic range BPM signal detector has been on the most wanted list of Argonne Wakefield Accelerator (AWA) Test Facility for many years. Unique capabilities of AWA beamline require BPM instrumentation with an unprecedented dynamic range, thus cost effective solution could be challenging to design and prototype. Our most recent design, and the results of our quest for a solution, are shared in this paper.
Euclid Beamlabs, Bolingbrook, USA
ANL, Lemont, Illinois, USA
TUB, Beijing, People’s Republic of China
Illinois Institute of Technology, Chicago, Illinois, USA
Euclid TechLabs, Solon, Ohio, USA
As part of the Argonne 500 MeV short pulse Two Beam Wakefield Acceleration Demonstrator, a single cell X-band dielectric disk loaded accelerator (DDA) has been designed, fabricated, and tested at high power at the Argonne Wakefield Accelerator. The DDA should provide a short pulse (~20 ns) high gradient (>300 MV/m) accelerator while maintaining a reasonable r/Q and high group velocity. This will allow a significantly larger RF-to-beam efficiency than is currently possible for conventional accelerating structures. A low loss barium titantate ceramic, µr = 50, was selected, and a low temperature brazing alloy chosen to preserve the dielectric properties of the ceramic during brazing. High power testing produced breakdown at the triple junction, resulting from the braze joint design. No evidence of breakdown was observed on the iris of the disk, indicating that the maximum surface electric field on the dielectric was not reached. An improved braze joint has been designed and is in production, with high power testing to follow.
ANL, Lemont, Illinois, USA
The Argonne Wakefield Accelerator (AWA) Test Facility has used a completely homebrewed, MS Windows-based control system for the last 20 years. In an effort to modernize the control system and prepare for an active machine learning program, the AWA will work with the Advanced Photon Source (APS) controls group to upgrade its control system to EPICS. The EPICS control system is expected to facilitate collaborations and support the future growth of AWA. An overview of the previous AWA control and data acquisition system is presented, along with a vision and path for completing the EPICS upgrade.
ANL, Lemont, Illinois, USA
LBNL, Berkeley, California, USA
The Argonne Wakefiled Accelerator (AWA) Test Facility designed and operated a homemade LLRF system for the last 20 years. It is based on NI-PXI products that has now become obsolete. The AWA’s LLRF cannot keep up with the increasing stability demands of AWA’s upgraded facility. An overhaul of the system is strongly desired. With the support from DOE-HEP, the AWA is collaborating with Lawrence Berkeley National Laboratory (LBNL)to upgrade its LLRF system with modern instrumentation to meet the growing stability demands. An overview of AWA’s current LLRF system performance is presented together with the upgrade plan and expectations.
Euclid TechLabs, Solon, Ohio, USA
ANL, Lemont, Illinois, USA
Euclid Beamlabs, Bolingbrook, USA
MIT/PSFC, Cambridge, Massachusetts, USA
SLAC, Menlo Park, California, USA
Fermilab, Batavia, Illinois, USA
Northern Illinois University, DeKalb, Illinois, USA
IIT, Chicago, Illinois, USA
High brightness beams appealing for XFELs and UEM essentially imply a high current and a low emittance. To obtain such beams we propose to raise the accelerating voltage in the gun mitigating repealing Coulomb forces. An ultra-high gradient is achieved utilizing a short-pulse technology. We have designed a room temperature X-band 1,5 cell gun that is able to inject 4 MeV, 100 pC bunches with as low as 0.15 mcm normalized transverse emittance. The gun is operated with as high gradients as 400 MV/m and fed by 200 MW, 10 ns RF pulses generated with Argonne Wakefield Accelerator (AWA) power extractor. We report results of low RF power tests, laser alignment test results, and successful gun conditioning results carried out at nominal RF power.
Euclid TechLabs, Solon, Ohio, USA
ANL, Lemont, Illinois, USA
Euclid Techlabs has been designing and testing a cost-effective iris diaphragm beam halo/profile detector, which can be easily configured to work with various primary beam energies and sites. Besides working as a measurement device, it can also work as a controllable beam scraper/collimator. This novel iris diaphragm detector utilizes the current signal produced by the beam charge deposition on the moveable conductive iris blades, to accurately measure the beam distribution from the outlier to the beam core. In this paper, we discuss the recent developments of our iris diaphragm e-beam apparatus series (IDEAS)-halo detector, including its geometry upgrades and newest beam experiments done at the AWA cathode testbed (ACT) of Argonne National Laboratory.
ANL, Lemont, Illinois, USA
Euclid TechLabs, Solon, Ohio, USA
Northern Illinois University, DeKalb, Illinois, USA
ANL, Lemont, Illinois, USA
RadiaBeam, Santa Monica, California, USA