# Difference between revisions of "LB Feb 2017 Geometric Efficiency Calculations"

Below are the theoretical calculations for the theoretical decay frequencies

Na-22, 10.19 uCi on July 15, 2013, half life 2.602 +/- 0.002 years, 99.937% for 1274.52 keV line and 178.8 for 511 keV line , activity in Feb 4, 2017 = 3.947 uCi

= for the 1274 keV line
= for the 511 keV line

Now compute the expected rate for February 5, 2017.

The activity on Feb 5, 2017 is 3.944 uCi, so the expected rates for the 2 lines are

= for the 1274 keV line
= for the 511 keV line

Below is a table where the actual efficiency will be calculated for position R (farthest position).

 Run Source Energy (keV) Expected Rate (Hz) HpGe Rate (Hz) HpGe Det D Efficiency (%) r5825 Na-22 511 79122.6 (480:540) (4.309-0.065=4.244) 0.005 r5826 Na-22 511 28091.2 (480:540)(1.105-0.02281=1.0821) 0.004 r5827 Na-22 511 861.1 (480:540)(0.04037-0.009123=0.031247) 0.004 r5829 Na-22 511 137692 (480:540)(3.686-0.01939=3.67) 0.003 r5830 Na-22 511 44224 (480:540) (1.073-0.0057=1.0673) 0.002 r5831 Na-22 511 139058.52 (480:540)(3.283-0.05702=3.22598) 0.002