1 5 0 ▁ke V . ▁The ▁detect ors ▁consisted ▁of ▁ 2 3 - mm ▁thick ▁× ▁ 5 1 - mm ▁diameter ▁Cs I ( T l ) ▁cry st als ▁mounted ▁via ▁pl astic ▁light ▁tub es ▁to ▁phot om ult ip liers . ▁The ▁hard ▁det ector ▁changed ▁its ▁operating ▁mode ▁depending ▁on ▁( 1 ) ▁measured ▁count ▁rate , ▁( 2 ) ▁ground ▁command , ▁or ▁( 3 ) ▁change ▁in ▁space craft ▁te lem etry ▁mode . ▁The ▁trigger ▁level ▁was ▁generally ▁set ▁for ▁ 8 - sigma ▁above ▁background ▁and ▁the ▁sens itivity ▁is ▁ 1 0 − 6 ▁erg / cm 2 ▁( 1 ▁n J / m 2 ). ▁When ▁a ▁burst ▁trigger ▁is ▁recorded , ▁the ▁instrument ▁switch es ▁to ▁record ▁high ▁resolution ▁data , ▁recording ▁it ▁to ▁a ▁ 3 2 - k bit ▁memory ▁for ▁a ▁slow ▁te lem etry ▁read ▁out . ▁Bur st ▁data ▁consist ▁of ▁either ▁ 1 6 ▁s ▁of ▁ 8 - ms ▁resolution ▁count ▁rates ▁or ▁ 6 4 ▁s ▁of ▁ 3 2 - ms ▁count ▁rates ▁from ▁the ▁sum ▁of ▁the ▁ 2 ▁detect ors . ▁There ▁were ▁also ▁ 1 6 ▁channel ▁energy ▁spect ra ▁from ▁the ▁sum ▁of ▁the ▁ 2 ▁detect ors ▁( t aken ▁either ▁in ▁ 1 , ▁ 2 , ▁ 4 , ▁ 1 6 , ▁or ▁ 3 2 ▁second ▁integr ations ). ▁During ▁' wait ' ▁mode , ▁the ▁data ▁were ▁taken ▁either ▁in