, ▁by ▁contrast , ▁had ▁sens itivity ▁to ▁all ▁three ▁neut r ino ▁flav ours . ▁By ▁simultaneously ▁meas uring ▁the ▁electron ▁neut r ino ▁and ▁total ▁neut r ino ▁flux es ▁the ▁experiment ▁demonstrated ▁that ▁the ▁supp ression ▁was ▁due ▁to ▁the ▁MS W ▁effect , ▁the ▁conversion ▁of ▁electron ▁neut r inos ▁from ▁their ▁pure ▁flav our ▁state ▁into ▁the ▁second ▁neut r ino ▁mass ▁eigen state ▁as ▁they ▁passed ▁through ▁a ▁reson ance ▁due ▁to ▁the ▁changing ▁density ▁of ▁the ▁Sun . ▁The ▁reson ance ▁is ▁energy ▁dependent , ▁and ▁" turn s ▁on " ▁near ▁ 2 Me V . ▁The ▁water ▁C eren kov ▁detect ors ▁only ▁detect ▁neut r inos ▁above ▁about ▁ 5 Me V , ▁while ▁the ▁radio chem ical ▁experiments ▁were ▁sensitive ▁to ▁lower ▁energy ▁( 0 . 8 Me V ▁for ▁ch lor ine , ▁ 0 . 2 Me V ▁for ▁gal li um ), ▁and ▁this ▁turned ▁out ▁to ▁be ▁the ▁source ▁of ▁the ▁difference ▁in ▁the ▁observed ▁neut r ino ▁rates ▁at ▁the ▁two ▁types ▁of ▁experiments . ▁ ▁Pro ton – pro ton ▁chain ▁All ▁neut r inos ▁from ▁the ▁pro ton – pro ton ▁chain ▁reaction ▁( PP ▁neut r inos ) ▁have ▁been ▁detected ▁except ▁he p ▁neut r inos ▁( next ▁point ). ▁Three ▁techniques ▁have ▁been ▁adopted : ▁The ▁radio chem ical ▁technique , ▁used ▁by ▁Hom est ake , ▁Gal lex , ▁G NO ▁and ▁S AGE ▁allowed ▁ ▁to ▁measure ▁the ▁neut r