FMIT Beamstop

The Fusion Material Irradiation Test (FMIT) and FMIT prototype beamstops provide several unique design challenges. The prototype beamstop must be capable of handling 500 kW of continuous power; the FMIT beamstop must handle 3500 kW of power in a pulsed form. The particle involved is H2+. These beamstops must convert these energies to heat that is carried away by cooling water, while being contained in a relatively compact package, tolerant of changes in beamspot shape and size. The range of the beam is less than 0.1 mm in the prototype beamstop and less than 3 mm in the FMIT beamstop; thus energy cannot be spread over the depth of the absorbing material very readily. Long-term irradiation of the materials used must be kept low, to minimize maintenance problems, requiring consideration of materials. Material distortion from thermal effects also must be considered.