Gas sheet monitor diagnositc for intense charged particle beams

Accelerators for light sources, and high-energy physics, require non-destructive and non- interceptive diagnostics for measuring beam profiles. Typical diagnostics based on solid materials or reflectors will not withstand high intensities and pose potential for radiation damage. In this proposal, we investigate the use of a tailored gas sheet distribution to supplant traditional metal foils. As the particle beam interacts with the gas sheet, ionization products are generated, and transported via an electrostatic column, to an imaging detector. The ion distribution at the detector plane has a direct correlation to the transverse profile in the particle beam. The approach does not disturb the particle beam and is modular and scalable to different beam facilities. In Phase I, a scalable start-to-end simulation suite that models the interaction and output of the diagnostic was developed. The approach was used to model test cases for facilities at the SLAC National Accelerator Laboratory. The toolkit includes detailed simulations on the fluid dynamics of generating a thin gas sheet at the interaction region and specifying the differential pumping requirements to maintain adequate vacuum levels. The studies also include ionization of neutral gas by relativistic beams, and design of the electrostatic column. Detailed engineering on key subcomponents was performed to identify potential bottlenecks in prototyping. The Phase II efforts are focused on realizing a gas-sheet view-screen. The efforts include optimization of the system for facility size constraints, and engineering and fabricating key custom components such as the interaction chamber, the gas shaping nozzles, the electrostatic column, and the gas evacuation section. The end result will be a prototype diagnostic that is deployed to the accelerator and commissioned with live beam. The results of these efforts can provide immediate benefits for accelerators for light source facilities and high-energy physics that require high resolution characterization of beams in a non- invasive manner. The design is flexible and will find use in many different facilities.