Appendix A INSTRUMENTATION Shelf geometries from bottom of window: A.1 COLLECTOR IDENTIFICATION Collector designations are shown in Figure A.1. A.2. Physical Geometry DETECTOR DATA A.2.1 End-Window Counter. Crystal dimensions and type: 14-inch diameter x 4 inch thick, Nal(T1), Harshaw Photomultiplier tube type: 6292 DuMont Scaler types: Model 162 Nuclear Instrument Cor- Shelf Distance Correction 1 2 3 4 5 0.85 1.50 2.15 3.75 5.35 0.2628 0.1559 0.0958 0.0363 0.0177 cm Minimum count rate requiring coincidence loss correction: 3.0 x 10° counts/min poration, and Model 182 Nuclear-Chicago (in tandem) Pb shield dimensions: 84-inch outside diameter x 20 inches high x 114 inches thick; additional 2-inch A.2.3 4-m lonization Chamber (Analytical and Stand. ards Branch). (Two newer chambers of modified design were also used. The response of these to 100 ug thickness in Site Elmer laboratory Counting chamber dimensions: 5'4-inch diameter x 4 inches high Al absorber thickness: 44 inch of Ra= 700 x 107° maat 600 psi; therefore, all read- Shelf cision resistors (1 percent) eliminated scale correction factors. ) ings were normalized to the latter value. Shelf distances from bottom of absorber: Distance moon cm 5 Gas type and pressure: A ~ 600 psi Shield dimensions: Pb ~ 19-inch outside diameter 22 inches high x 4 inches thick; additional 1-foot thickness of sandbags in Site Elmer laboratory Counting chamber dimensions: 1l-inch diameter x 14 inches high 1.0 2.6 4.2 5.8 7.4 Thimble dimensions: 14-inch inside diameter x Ratios to Shelf 5 (most commonly used) for cen- 12 inches deep Useful range: ~ 217 x 1071! ma (background) to tered Ca**" point source: Oo f& WN eH Shelf 200 x 107* ma Ratio Correction factors to equivalent 10° scale: 5.87 3.02 Scale Factor ~ ohms 1.88 1.31 1.00 Use of pre- 10%# . 0.936 1028 0.963 10° 1.000 10° Minimum count rate requiring coincidence loss correction: 1.0 x 10° counts/min Counting procedure: ordinarily 3- to l-minute intervals for each sample 1.000 Response versus sample (Ra) position: A.2.2 Beta Counter. Gas proportions: 90 percent A, 10 percent CO, Pb shield dimensions: 8'4-~inch outside diameter Distance from Bottom of Tube Relative Response in pet 0 to 3 , 3.5 to 5.5 x 12 inches high x 114 inches thick; additional 2-inch thickness in Site Elmer laboratory Counting chamber dimensions: 5/4-inch diameter x 4 inches high Al window thickness: 0.92 mg/cm? 100 99 to 92 Response to 100 yg Ra: 5.88 x 107* ma at ~ 600 psi Efficiency factors relative to Cofor various nuclides: 162