| 研究実績の概要 |
My research in FY2015 focussed on the refining and prototyping of the designs of the gas injection, light collection and photon detection systems for a beam induced fluorescence monitor. Concerning the gas injection system, I collaborated with Dr. Megan Friend at KEK to build a prototype vacuum chamber at J-PARC to test the gas injection with a leak valve and pumping with a turbo-molecular pump. This system is now fully operational and is being used to confirm the simulation of candidate gas injection systems. Concerning the light collection system, a prototype plano-convex focussing system was designed and simulated and is being built. For light transport, silica optical fibers have been tested in the T2K beam line. From these tests it has been confirmed that no large background light sources are present from the beam pipe during beam operation, indicating that the beam induced fluorescent light will dominate. However, scintillation of the fiber from ionizing radiation has been identified as a possible source of background light. This has led to plans to test alternative silica fibers with different buffer materials. I also carried out additional tests of irradiated fibers in the T2K beam line to confirm no degradation of light transmission properties. Concerning the photon detection, the operation of multi-pixel photon counters at a distance of 30 meters from the beam line was confirmed. A CID camera was also tested and no significant backgrounds from ionizing radiation were observed.
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