Improved assessment of power dissipation in rearmost plate of new-style ISIS neutron-producing target using a novel lumped parameter approach

A previous analysis of beam power dissipation in the new-style multi-plate neutron-producing tantalum-clad tungsten target in the First Target Station (TS-1) of the ISIS Spallation Neutron and Muon Source resulted in a value for the thermal power dissipated in the rearmost plate of the target that was significantly smaller than the power dissipation predicted by Monte Carlo particle-tracking codes. In the present paper a lumped thermal network is developed with a view to enabling an improved analysis to be made. A larger value for the power dissipation in the rearmost plate is obtained, but is still noticeably smaller than predictions from Monte Carlo codes.