Status of the Japan Proton Accelerator Research Complex H^{-} ion source

A cesium-free H^{-} ion source driven by a LaB_{6} filament is being operated for the beam commissioning of the accelerators at Japan Proton Accelerator Research Complex (J-PARC). The beam commissioning started in November 2006. As of June 2008, there have been 17 beam commissioning runs. The duration of each run was approximately 4–5 weeks. In these runs, the ion source has succeeded in providing beam to the J-PARC accelerators for 2720 hours. The interruption time due to the failure of the ion source is only approximately 50 hours. The availability of the ion source is calculated to be 98%. Since the fluctuation of the beam current is small, tuning the beam current once a day is sufficient to maintain the beam current within the error of a few percent. Recently, the ion source succeeded in producing the beam current of 36 mA with a flattop pulse width of 500 μs and a repetition rate of 25 Hz as required for the first stage of J-PARC