title: Fiber optic picosecond laser pulse transmission line for hydrogen ion beam longitudinal profile measurement.
abstract: We present a fiber optic laser pulse transmission line for nonintrusive longitudinal profile measurement of the hydrogen ion (H(-)) beam at the front-end of the Spallation Neutron Source accelerator. The 80.5 MHz, 2.5 ps, multikilowatt optical pulses are delivered to the accelerator beam line through a large-mode-area polarization-maintaining optical fiber to ensure high measurement stability. The transmission efficiency, output laser beam quality, pulse jitter, and pulse width broadening over a 30 m long fiber line are experimentally investigated. A successful measurement of the H(-) beam microbunch (~130 ps) profile is obtained. The experiment is the first demonstration to our knowledge of particle beam profile diagnostics using a fiber optic laser pulse transmission line.
authors.affiliation: Spallation Neutron Source, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, USA.
authors.forename: Chunning
authors.initials: C
authors.lastname: Huang
authors.forename: Yun
authors.initials: Y
authors.lastname: Liu
authors.forename: Alexander
authors.initials: A
authors.lastname: Aleksandrov