- 8 - UCRL-4505 The disintegration rate of a sample was determined by the equation: disintegrations/min = (counts /min) 5. tow 100 g in which tow is the correction for air gap and window absorption, fo the total scattering factor as defined by the ordinates of Fig. 3, and g is the percent physical geometry for the counter (3.11 percent) as measured by a Radium DEF Standard or by the 100 percent geometry counter. ‘The following is a summaryof the chemistry and counting techniques used for the nuclides included in the excitation functions of Fig. 2. sr 89, Initial separation was delayed for one week so that the 9. 7-hour sr?! could decay to undetectable levels in order to avoid interfering radioactivity of the 61-day y7l, The Sr was separated with Ba as the nitrate, scavenged with Fe(OH), using NH, gas, the Ba removed by repeated precipitation of BaCroO, from NH,Ac solution (pH 5), and finally the precipitation of Sr as the carbonate. Zr 97, Initial separation was performed immediately after bombard- ment since its precursors are presumed to be short. The zirconium was extracted into 0.4M thenoyltrifluoroacetone (TTA) in benzene from 4M HCl or HNO, after initial extraction of the aqueous phase by diisopropyl ketone. The TTA phase was washed three times with 4M HNO3; evaporated to dryness, and ignited to ZrO,. pgi pa! i2. Separation of the Pd fraction was made about two hours after bombardment so that more than 99.9 percent of the 22-minute pal}! could decay; and thus minimize the Agi} contamination of the final Pd fraction. A correction was made for the activity of the 3. 2-hour Agi t4 daughter of pal lé 6N HCl The Pd was separated as the sulfide from and as the dimethylglyoxime (DMG). Scavenges of Fe(OH), and AgCl were used, and the Pd was placed onto a Dowex A-1 column (5 x 0.3 cm of 200 to 300 mesh) with dilute HCl. The column was washed with 0. 1M HCl and 1. 5N H,50,; and the Pd eluted with IN NH, OH. I0018b1 The