ORNL, Oak Ridge, Tennessee
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
Paul Scherrer Institute, Spallation Source Division, ASQ, Villigen PSI
There are three spallation neutron source facilities in the world with the potential of operating in the one megawatt proton beam power range. The SINQ facility at the Paul Scherrer Institut has already operated in this power range for several years with various water-cooled solid targets, and used a liquid metal (lead-bismuth) target for a period of four months in conducting its successful MEGAPIE project in 2006. The Spallation Neutron Source (SNS) facility at Oak Ridge National Laboratory began operation in 2006 and is approaching the one megawatt level using a liquid mercury target. The Japan Proton Accelerator Research Complex (J-PARC), which also has a mercury target, began beam-on-target operations in 2008 and is on its way to ramping-up its power level to one megawatt over the next few years. This paper will summarize the operating experience and planned improvements for the spallation targets at these megawatt class facilities.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
J-PARC, KEK & JAEA, Ibaraki-ken
In J-PARC, Materials and Life Science Facility (MLF) is aimed at promoting experiments using the world highest intensity pulsed neutron and muon beams which are produced at a thick mercury target and a thin carbon graphite target, respectively, by 3-GeV proton beams. The first beam was achieved at the target without significant beam loss. To obtain the beam profile at the target, we applied an activation technique by using thin aluminum foil. In order to obtain reliable profile, it is required that a small number of shots for the beam adjustment and the beam stability. Since beam monitors works very well located at the beam transport line even in the first beam, the beam centralization can be finished by very small number of shots. The stability of beam for each pulse is recognized to be smaller than 1 mm. After many shots of irradiation, the 2-D beam profile can be obtained. It is found that the observed profile shows good agreement with the prediction calculation including the beam scattering at the proton beam window. The beam emittance is measured by the MWPM. It is found that the rms-beam emittance agree with the calculation by the SIMPSONS.