Development of a high average power laser generating electron beam in ILC format for KEK-STF

Aim of Super-conducting Test Facility (STF) at KEK is demonstrating technologies for International Linear Col-lider(ILC). In STF, one full RF unit, which is composed from one klystron, three Cryo-modules, and 24 RF cavities, will be developed and beam acceleration test will be made. In super-conducting accelerator, precise RF control in phase and power is essential because the input RF power should be balanced to beam accelerating power. To demonstrate the system feasibility and reliability, the beam acceleration test is an important step in R&D phase. To provide ILC format beam for STF, we develop an electron source based on photo-cathode L-band RF gun. In this article, the laser system generating ILC format beam is described. The laser system consists from Yb fiber oscillator, macro-pulse profiler, Nd: YLF amplifier and Harmonic Generations. The laser system is initially developed at Institute for Applied Physics(IAP), Nizhny-Novgorod, Russia and moved to KEK-STF, Japan for the experiment. The laser system meets the basic ILC requirements; One macro-pulse contains 2439 micro pulses with 369ns bunch spacing; The macro-pulse is repeated in 5Hz; The micro-pulse energy is 1.9μJ, which corresponds to 4.3nC assuming 1.0% quantum efficiency of cathode. We report the basic performance of the laser system from the accelerator technology point of a view.