Experimental Approaches of Emittance Dilution Induced by Misalignments in a Photoinjector

One of the main issues in the generation of a highbrightness electron beam is the preservation of beam emittance. Here we discuss one of possible source of the emittance dilution by the rf kick due to misalignment. The emittance of a high-brightness electron beam from a photoinjector is affected by the status of alignments due to deflection force by the accelerating field. The misaligned beam with the accelerating field axis experiences emittance growth by an electron-beam defection that is proportional to the electric field strength in the cavity. Misalignments of beam axis induce different deflections on beam particles with energy spread, causing emittance dilution of the beam. In order to reduce the emittance dilution the photoinjector is required well alignments of all components. We show significant emittance growth as misalignments function against the electron beam-axis to accelerating column.