PC , ▁where ▁they ▁are ▁detected ▁by ▁the ▁Micro M eg as ▁providing ▁a ▁ 3 D ▁image ▁of ▁a ▁path ▁of ▁the ▁travers ing ▁charged ▁particle . ▁Y ▁and ▁Z ▁coordinates ▁are ▁based ▁on ▁the ▁position ▁of ▁the ▁detected ▁ion isation ▁electrons ▁on ▁the ▁Micro M eg as ▁modules , ▁and ▁X ▁coordinate ▁is ▁based ▁on ▁the ▁electrons ▁dr ift ▁time . ▁In ▁the ▁magnetic ▁field , ▁the ▁curv ature ▁of ▁this ▁path ▁allows ▁to ▁determine ▁charge ▁and ▁momentum ▁of ▁the ▁particle , ▁and ▁the ▁amount ▁of ▁the ▁ion isation ▁electrons ▁per ▁unit ▁distance ▁is ▁used ▁to ▁identify ▁particles ▁based ▁on ▁the ▁Bet he - B lo ch ▁formula . ▁ ▁Fine - gra ined ▁detect ors ▁ ▁Two ▁fine - gra ined ▁detect ors ▁( F G D s ) ▁are ▁placed ▁after ▁the ▁first ▁and ▁second ▁T PC s . ▁T ogether ▁the ▁F G D s ▁and ▁T PC s ▁make ▁up ▁the ▁tra cker ▁of ▁N D 2 8 0 . ▁The ▁F G D s ▁provide ▁the ▁active ▁target ▁mass ▁for ▁the ▁neut r ino ▁interactions ▁and ▁are ▁able ▁to ▁measure ▁the ▁short ▁tracks ▁of ▁pro ton ▁re co il . ▁The ▁first ▁F G D ▁is ▁composed ▁of ▁sc int ill ator ▁layers ▁only , ▁while ▁the ▁second ▁F G D ▁is ▁composed ▁of ▁altern ating ▁layers ▁of ▁sc int ill ator ▁and ▁water . ▁The ▁second ▁F G D ▁is ▁partially ▁composed ▁of ▁water ▁because ▁the ▁det ector ▁at ▁Super - K ami ok ande