Nuclide Factor Ce? He”93 Aut csi? se“® 0.186 0.282 0.355 0.623 0.884 Co™ K@ Na™4 Shelf Ww re ee cm 4 1.000 1.205 Tray distance from bottom of detector when outside and Cs!" Calibration procedure: one per day and one following each adjustment of amplifier or detector voltage Counting procedure: equal counting times for each series on a given sample A.2.4 Well Counter. Nuclear-Chicago Model DS-3 Crystal dimensions and type: 174-inch diameter x2 inches thick, NaI(T1) Well dimensions: °*4~inch diameter x 144 inches deep A.2.6 Doghouse Counter (Reference 43) Photomultiplier tube type: 6292 DuMont Scaler type: Model MPC-1 Berkeley, or Nuclear Instrument Corporation 162 with Nuclear-Chicago 182 in tandem Crystal dimensions and type: Pb shield thickness: 1'4 inches, with °4-inch diam- Pb shield thickness (counting chamber): 2 inches Counting chamber dimensions: 20 x 24 x 34 inches high Size of hole in roof of counting chamber for detector: 7-inch diameter Distance from bottom of sample tray to bottom of crystal: 36 inches Sample tray dimensions: 18 x 21 x 2 inches deep Counting efficiency for several point-source nu- Relative Count Rate pet 100 99.2 3.9 (~ well depth) 90.6 Efficiency for several nuclides: Nuclide . OT, Anis Co™ ps inch thick Photomultiplier tube type: 6292 DuMont Scaler type: Model 162 Nuclear Instrument Corporation, and Model 182 Nuclear-Chicago (in tandem) Pb shield dimensions (detector): 10-inch diameter x 20 inches high x 114 inches thick (15 x 125 mm): 1.81 1l-inch diameter x 1 inch thick, Nal(T1), Harshaw aluminum absorber ‘4- eter hole above crystal well; additional 2-inch thickness in YAG 40 laboratory Counting rate versus sample volume in test tube 0.01 2.07 4.76 5.25 6.84 of 4-inch diameter collimator: 13.95 cm Calibration standards: Ba’, Ce! Hy3 Na”, 1.312 Sample Volume ml Distances clides, centered in bottom of tray with '4-inch aluminum cover in place: Efficiency counts /dis Nuclide counts/dis x 107 0.42 Na Na 1.70 0.936 0.51 se4* 1.16 —— k# 0.43 Co* Nb" Ca87_pais™m Cel! Aut He**3 Minimum count rate requiring coincidence loss correction: 1.0 x 10® counts/min Counting procedure: minimum of 10‘ counts to Maintain a statistical error of ~ 1.0 percent A.2.5 20-Channel Analyzer. 0.151 1.02 0.506 0.548 0.622 0.711 0.842 Relative counter photon efficiency, computed for total aluminum thickness = '4 inch (3.43 gm/cm’): Crystal dimensions and type: 2-inch diameter x 2 inches thick, Nal(T1) Glow transfer tube types: GC-10B and GC-10D Fast register type: Sodeco Voltage gain (with delay line pulse shaping): 1,000 Attenuation (with ladder attenuator): 63 decibels in I~decibel steps Pb shield thickness: ~2 inches Counting chamber dimensions: 8-inch diameter «34 inches high Shelf distances from bottom of detector: 163 Energy Mev Efficiency pet 0.01 0.02 0.03 0.05 0.07 0.10 0.15 0 0.0034 3.24 33.3 48.7 57.8 63.7