Development of bonding technique of Au-In-Cd alloy as thermal neutron absorber material for spallation neutron source

Teshigawara, Makoto   ; Oi, Motoki ; Harada, Masahide   ; Kasugai, Yoshimi  ; Takada, Hiroshi   

The Japan Spallation Neutron Source (JSNS) is a 1 MW pulsed neutron source of the Japan Proton Accelerator Research Complex (J-PARC). A thermal-neutron-absorber material (Au-In-Cd alloy), called decoupler, is developed to obtain a neutron beam pulse with narrow width and fast decay (short tail). In order to utilize the Au-In-Cd decoupler, we need to make the bonding between Au-In-Cd and aluminum alloy (A5083), which is structural material of moderator with curved shape in terms of the heat removal (5 W/cm at maximum) and thermal stress. A Hot Isostatic Pressing (HIP) technique is adopted to obtain the bonding the Au-In-Cd alloy to the A5083. We found that the diffusion bonding was confirmed between the Au-In-Cd and A5083 alloy under the condition of the temperature of 490C to 550C (five cases), pressure of 100 MPa and holding time of 1 hour. In case of 535C, the intermetallic compound grown in the second diffusion layer from A5083 was confirmed, however, the strength for 535C gave three times higher than that of design requirement (30MPa).