Convection-type LH2 absorber R&D for muon ionization cooling

A feasibility study on liquid hydrogen (LH2) absorbers for muon ionization cooling is reported. In muon ionization cooling, an LH2 absorber is required to have a high cooling power greater than 100W to cool heat deposited by muons passing through. That heat in LH2 can be removed at either external or internal heat exchangers, which are cooled by cold helium gas. As one of the internal heat exchanger types, a convection-type absorber is proposed. In the convection-type absorber, heat is taken away by the convection of LH2 in the absorber. The heat exchanger efficiency for the convection-type absorber is calculated. A possible design is presented.