Since its establishment, the B-factory at KEK has been operating successfully, achieving successive world records for the luminosity of electron-positron colliders. The factory has also conducted experimental tests related to the Kobayashi-Maskawa theory. First of all, large CP violation was discovered in the B meson system, which is one of the predictions of the model. This was followed by confirmation in various B meson decays. On the other hand, some phenomena have been found which may not be fully explained by the model alone. Expectations are high for clarification using upgraded B-factory(ies).
This year, Heavy Ion Medical Accelerator in Chiba (HIMAC) of National Institute of Radiological Sciences celebrates its 15th anniversary of use in clinical trials. It has been brought up to the level accepted for general treatment at the suggestion of Lawrence Berkeley Laboratory (LBL). We are working on research and development aiming at further accumulation of results, the additional improvement of clinical results and overcoming obstinate cancers. While providing an outline of the present status and outlook of HIMAC, the applications of superconducting are considered.
We investigated the effect of the CeO2 buffer layer thickness on YBCO films prepared on CeO2/YSZ/CeO2-buffered Ni-electroplated Cu tapes. The thickness of the CeO2 layer was found to be critical. The thickness of the CeO2 seed layer was varied to be from 80 to 300 nm and the thickness of the CeO2 cap layer was varied to be from 40 to 80 nm. To avoid the formation of cracks, we found that the thicknesses of the CeO2 seed layer and CeO2 cap layer must be less than 80 nm and 40 nm, respectively. Detailed SEM and AFM observations indicated a possible relation between the cause of crack formations and the thermal expansion coefficient differences of the films and the substrate. A smooth, continuous and crack-free surface was obtained on CeO2 (40 nm)/YSZ/CeO2 (80 nm) Ni-electroplated Cu tape. The YBCO films prepared on the CeO2/YSZ/CeO2-buffered Ni-electroplated Cu tapes revealed a transport Jc exceeding 3.6 MA/cm2 at 77 K in a self-field.