Development of Radiation Registant Optics System for High Intensity Proton Beamline at the J-PARC

Optical beam measurement such as OTR (Optical Transition Radiation), ODR (Optical Diffraction Radiation), gas Cherenkov, and so on is a powerful tool to observe a two-dimensional information of high intensity beam profile, so that this method is widely used at various electron and hadron accelerators. However, high radiation field to damage an optical system gradually becomes a major issue with increasing the beam intensity to explore new physics. Our present effort is devoted to develop a high efficient optical system to resist such high radiation field. We newly designed an optical system composed of two spherical mirrors which do not have any lenses vulnerable to radiation. We performed an optical test and confirmed that this optics has a resolution of 1.10±0.13 mm, which is within the design value of 2.95 mm. Also we conducted a beam test experiment of this optics system combined with an OTR screen performed at high intensity proton extraction beamline of the J-PARC.