▁Ne ut r ino ▁detection ▁The ▁weak ness ▁of ▁the ▁neut r ino ' s ▁interactions ▁with ▁other ▁particles ▁means ▁that ▁most ▁neut r inos ▁produced ▁in ▁the ▁core ▁of ▁the ▁Sun ▁can ▁pass ▁all ▁the ▁way ▁through ▁the ▁Sun ▁without ▁being ▁absor bed . ▁It ▁is ▁possible , ▁therefore , ▁to ▁observe ▁the ▁core ▁of ▁the ▁Sun ▁directly ▁by ▁detect ing ▁these ▁neut r inos . ▁ ▁History ▁ ▁The ▁first ▁experiment ▁to ▁successfully ▁detect ▁cos mic ▁neut r inos ▁was ▁Ray ▁Davis ' s ▁ch lor ine ▁experiment , ▁in ▁which ▁neut r inos ▁were ▁detected ▁by ▁obser ving ▁the ▁conversion ▁of ▁ch lor ine ▁nuc lei ▁to ▁radio active ▁arg on ▁in ▁a ▁large ▁tank ▁of ▁per ch lor o eth yl ene . ▁This ▁was ▁a ▁reaction ▁channel ▁expected ▁for ▁neut r inos , ▁but ▁since ▁only ▁the ▁number ▁of ▁arg on ▁dec ays ▁was ▁counted , ▁it ▁did ▁not ▁give ▁any ▁direction al ▁information , ▁such ▁as ▁where ▁the ▁neut r inos ▁came ▁from . ▁The ▁experiment ▁found ▁about ▁ 1 / 3 ▁as ▁many ▁neut r inos ▁as ▁were ▁predicted ▁by ▁the ▁standard ▁solar ▁model ▁of ▁the ▁time , ▁and ▁this ▁problem ▁became ▁known ▁as ▁the ▁solar ▁neut r ino ▁problem . ▁ ▁While ▁it ▁is ▁now ▁known ▁that ▁the ▁ch lor ine ▁experiment ▁detected ▁neut r inos , ▁some ▁phys ic ists ▁at ▁the ▁time ▁were ▁susp icious ▁of ▁the ▁experiment , ▁mainly ▁because ▁they ▁did ▁not ▁trust ▁such ▁radio chem ical ▁techniques . ▁Un ambigu