100 | SINGLE~CRYSTAL. 10 | 203 ~ BACK GROUND 4 CRYSTALS ARE 4 IN. THICK — AND 6 iN. IN DIAMETER —_ Lad Z < TWO-CRYSTAL a COINCIDENCE BACKGROUND & als SO a 2 ex 1-1N. LEAD ABSORBER SAMPLE POSITION wv _ a z = 0.01 om o> f ~ \s \ S 0.001 \ N \\ — \ ~N 0.0001 . 0.00001 ~\ aN | i \. | ~ ~\ L 2 ENERGY, MEV Fig. 4—Com parison of the background of a singlecrystal detector with that of the two-crystal multidimensional detector sysbern, N ~ wy | 3 100 4 . <] ~ Lote 5 ~ — La. L — Sp es TOTAL COUNTING Fig. 5—Total counting efficiency and total coincidence counting efficiency of the two- TITTTTY So COUNTING EFFICIENCY, % EFFICIENCY, 2E 5 crystal multidimensional detector system. a TOTAL COINCIDENCE COUNTING EFFICIENCY, 2£? 4 - 2 0.1 po 0.2 0.4 0.6 0.8 1.0 ENERGY, MEV 2 3