FIG. 7.

Comparison of the effects of spectral instability in liquid and gel scintillator. The estimated disintegration rates are for samples containing only ¹³¹I-labeled RISA in liquid (top) and gel (bottom). Open and closed symbols represent separate runs on duplicate samples. (Top) Liquid system data representing duplicate 100-ml samples containing 0.22 mCi ¹³¹I-labeled RISA in 4.2 ml Aquasol. Liquid system window channels were window 1 (5–400), window 2 (400–670), and window 3 (670–860). (Bottom) Gel system data representing duplicate 100-ml samples containing 0.25 mCi ¹³¹I-labeled RISA in 2.3 ml of 1:8000 diluted saturated picric acid and 3.6 ml RediSolv MP. Both tests were performed in glass minivials. Gel system window channels were window 1 (5–300), window 2 (300–550), and window 3 (550–800).