@article{oai:nifs-repository.repo.nii.ac.jp:00011425, author = {MOTOJIMA, Gen and YOSHIDA, Naoaki and MURASE, Takanori and TANAKA, Hirohiko and MASUZAKI, Suguru and SAKAMOTO, Ryuichi and TOKITANI, Masayuki and MATSUMOTO, Kenji and MIYAMOTO, Mitsutaka and YAJIMA, Miyuki and SAKAMOTO, Mizuki and YAMADA, Hiroshi and MORISAKI, Tomohiro and LHD Experiment Group}, journal = {Plasma and Fusion Research}, month = {Sep}, note = {0000-0001-5522-3082, An innovative color measurement technique is employed in the Large Helical Device (LHD). This study provides a method for obtaining in broad spatial extent and in great detail the color information of the first wall relating to the thickness of the deposition layer. The RGB (Red, Green, and Blue) value, mainly of the stainless steel plates on the helically twisted coil, is measured by a color analyzer equipped with an integrated sphere light source. On the outer torus side, the colors of almost all stainless steel plates are close to carbon black, which suggests that deposition is dominant. On the inner torus side, all plates except for those neighboring the carbon divertor plates are almost white, as in the case of the stainless steel substrate of the first wall, which suggests that erosion is dominant. The relationship between the color and the distance from the stainless steel plates to the plasma is investigated.}, title = {Preliminary Examination of Reflection Coefficient Measurement of RGB Lights on the First Wall in LHD}, volume = {10}, year = {2015} }