Abstract
We have designed a tool to measure the bunch length of an electron beam in a minimally invasive way by means of coherent Smith-Purcell radiation (SPR). The technique has been employed successfully at a test apparatus for the Mainz Energy-recovery Superconducting Accelerator MESA, demonstrating it is possible to determine the bunch length while losing less than 0.6% of the electron beam. The impact of the space charge on the bunch length can be reduced while tuning the longitudinal bunch preparation system during a live measurement at beam currents up to 1 mA. Doing so, RMS bunch lengths of $70\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ can be achieved in a typical operating mode of the low-energy beam transport system of MESA. In addition to the bunch length measurements, typical properties of the generated SPR are demonstrated.
Highlights
In order to investigate ultrafast physical processes, short pulses of particles have been receiving more and more attention
As the longitudinal bunch preparation system is installed here, this apparatus is suitable for bunch length measurements, even at high beam currents
The incoherent part of the Smith-Purcell radiation (SPR) cannot be observed because its intensity is below the background level; only coherent SPR can be observed, the power of which is in the order of pW to nW
Summary
In order to investigate ultrafast physical processes, short pulses of particles have been receiving more and more attention. Short electron bunches are needed to ensure acceleration of the beam without losing too many particles or, in other words, to match the accelerator acceptance. As the longitudinal bunch preparation system is installed here, this apparatus is suitable for bunch length measurements, even at high beam currents. In those circumstances, Coulomb interactions between the electrons lead to a blow-up of the whole bunch (space charge). For semirelativistic particles (β 1⁄4 0.548) the wavelength λ of the emitted radiation is in the order of magnitude of the grating period D and is dependent on the observation angle η and the order of diffraction n [3]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
