Experience on integrated interface at J-PARC/MLF

Takada, Hiroshi   

The pulsed spallation neutron source of J-PARC (JSNS) was designed to achieve best performance under close discussion between instrument scientists and neutron source engineering group. Representative specifications are as follows;1) The coupled moderator supplying high intensity cold neutrons was allocated bottom of the target independently while the decoupled and poisoned moderators for high resolution experiments were placed upper side of the target. 2) One shutter gate with single-channel neutron beam hole was prepared for individual neutron beam line so that users could use it exclusively. The followong is a more detailed example of integrated interface; Neutron instruments using the poisoned moderator such as high-resolution powder diffractometer, were required to allocate each other as narrow as possible because the pulse shape of the thermal and cold neutron degrade as the extraction angle increases from the normal to the moderator surface. We finally determined the narrowest angle between the beamlines as 6.7 degree considering the structural feasibility of the shutter interstitial blocks. The design of shutter inserts, validating netronic performance of new neutron beamline by the neutronics design group is also related to the integrated interface of J-PARC/MLF.