Development of sub-nm emittance diagnostics in accelerators
Fuhao Ji, Jorge Giner Navarro, Pietro Musumeci, Daniel Durham, Andrew Minor, Daniele Filippetto
The ability to measure small emittance (volume occupied by the beam in position-momentum phase space) is essential to the development of bright electron beams. CBB researchers and affiliates developed a technique to measure record low (sub-nm) emittances in accelerators using a nano-fabricated knife edge and novel phase space reconstruction algorithms. The reconstruction of the full transverse phase space of bright electron beams is obtained from the precise scan of the beam profile using a nano-fabricated knife-edge in the vicinity of the beam waist. The knife-edge diagnostics allows for a better control of phase space parameters for sub-um beams and, in particular, it has been applied to ultrafast electron diffraction and microscopy experiments. The algorithm has been experimentally demonstrated at the High Repetition-rate Electron Scattering (HiRES) beamline, a recently developed Ultrafast Electron Diffraction and Microscopy instrument at the Lawrence Berkeley Lab.
The development of such precise diagnostics are associated to the characterization of extremely low emittance beams.