“…The diagnostic aimed at fast ion research operated at TFTR [2], ASDEX Upgrade [3][4][5], TEXTOR [6,7], LHD [8,9], W7-AS [10,11], GDT [12,13], and will be installed at ITER [14]. The diagnostic is sensitive to the projection of the ion velocity distribution function on the direction of k 𝛿 [15].…”