Engineered Drop-in Systems for Plasma Wakefield Acceleration Experiments

Statement of the Problem Plasma wakefield accelerators show significant promise to shrink the size of particle accelerators and their development is well underway at DOE-funded user facilities. These ground-breaking experiments, however, are hampered by existing vacuum chamber technology. Specific issues include the large chamber weight and difficulty in quickly exchanging the chamber or its contents due to the limitations of current chamber technology. Technical Approach The introduction of de-constructable chambers will drastically decrease the installation weight of the chambers while the inclusion of spring-energized all-metal O-rings will increase the vacuum performance and radiation hardness of the large lids used to seal the chambers. Furthermore, will we introduce options for motorized precision alignment of multiple items from outside the vacuum envelope, include kinematic replaceable features, differential pumping, and other features uniquely required by plasma wakefield experiments. Phase I Results Motorized lids, quick-exchange flanges, kinematically-replaceable and air-side alignable in-vacuum breadboards were successfully prototyped demonstrated. These are building blocks of our modular, highly- alignable chamber concept. Prototyping of a light-weight chamber method was shown to not have positive economic benefits for other than extremely large chambers, but its technical success will be carried over to make light-weight motorized lids. In contrast, all-metal reusable O-ring seals were not demonstrated I the project timeline due to vendor constraints and integrated prototype could not be developed in time due to covid-related delays. Regardless, the Phase I work sets the bedrock for a promising new product with direct application to wakefield acceleration experiments. Phase II Plans We will build upon the success of our Phase I prototyping to build a complete, large-scale (4’ x 2’) chamber with direct and immediate usefulness for FACET-II. We will incorporate demountable chamber walls that can be exchanged for different experiments, motorized lids that allow for more compact installation and fast access, complete the design of a hydrocarbon- and particulate-free hexapod for precision alignment of dielectric structures, and various other features. The chamber will be developed in consultation with UCLA and provided as a test bed for the E-321 dielectric wakefield acceleration experiment. Commercial Applications and Other Benefits This program will yield vacuum chamber system suited for accelerator experimentalists and X-ray users. This will maximize investments already made by the DOE in user facilities by increasing the “beam on time.” Additionally, the vacuum chamber technology developed here offers lower base pressure and higher radiation resistance then other “large” chambers and is attractive to industry as a whole. Furthermore, accessories such as air-adjustability of in-vacuum lasers and true particulate-free hexapods will find a broader market in lasers, lithography, surface science, and other ultra-clean, ultra-precise fields.