Demonstration of a real-time interferometer as a bunch-length monitor in a high-current electron beam accelerator

J Thangaraj; G Andonian; R Thurman-Keup; J Ruan; A S Johnson; A Lumpkin; J Santucci; T Maxwell; A Murokh; M Ruelas; A Ovodenko

doi:10.1063/1.3698388

Demonstration of a real-time interferometer as a bunch-length monitor in a high-current electron beam accelerator

Rev Sci Instrum. 2012 Apr;83(4):043302. doi: 10.1063/1.3698388.

Authors

J Thangaraj¹, G Andonian, R Thurman-Keup, J Ruan, A S Johnson, A Lumpkin, J Santucci, T Maxwell, A Murokh, M Ruelas, A Ovodenko

Affiliation

¹ Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA. jtobin@fnal.gov

PMID: 22559527
DOI: 10.1063/1.3698388

Abstract

A real-time interferometer (RTI) has been developed to monitor the bunch length of an electron beam in an accelerator. The RTI employs spatial autocorrelation, reflective optics, and a fast response pyro-detector array to obtain a real-time autocorrelation trace of the coherent radiation from an electron beam thus providing the possibility of online bunch-length diagnostics. A complete RTI system has been commissioned at the A0 photoinjector facility to measure sub-mm bunches at 13 MeV. Bunch length variation (FWHM) between 0.8 ps (~0.24 mm) and 1.5 ps (~0.45 mm) has been measured and compared with a Martin-Puplett interferometer and a streak camera. The comparisons show that RTI is a viable, complementary bunch length diagnostic for sub-mm electron bunches.