Sheet Electron Probe for Beam Tomography

Advanced beam diagnostics are essential for high performance accelerator beam production and for reliable accelerator operation. It is important to have noninvasive diagnostics which can be used continuously with intense beams of accelerated particles. Noninvasive determination of accelerated particle distributions is the most difficult task of bunch diagnostics. Recently, a pencil electron beam probe was successfully used for the determination of accelerated particle density distributions. However, the apparatus used for this is large and complex, which complicates the broad use of this technique for tomography of accelerated bunches. In the novel device to be developed in this project, a simple, strip cathode provides a sheet beam probe for tomography instead of a scanning pencil beam that was used in previous electron probe bunch profile monitors. The apparatus with the strip cathode is smaller, has simpler design and less expensive manufacturing, has better magnetic shielding, has higher sensitivity, higher resolution, has better accuracy of measurement, and better time resolution. With this device it is possible to develop almost ideal tomography diagnostics of bunches in linear accelerators and in circular accelerators and storage rings. The development of a compact, reliable, and robust source of the sheet electron probe is vital for the successful development of the full tomography system. Computer codes for simulation of strip electron beam deflection by ultra-relativistic proton bunches will be developed in Phase I. A prototype of an electron probe with a strip cathode will be developed and tested in Phase I. Versions of thermionic cathodes will be developed and tested. In Phase II the full tomography system with improved hardware and software will be developed and tested at BNL. The proposed sheet electron probe tomography system with the strip cathode will be the most advanced system for detailed diagnostics of accelerated beams. It will be used in all advanced accelerators and storage rings such as EIC, FRIB, RHIC, SNS, LHC, ISIS, KEK and many others. This new diagnostic system will improve the operation of these and future multi-billion- dollar facilities for low cost.