Year
2002
Abstract
The present study shows how the detection of 662 keV and 344 keV gamma rays varied with detector angle for a shielded NaI detector. There was an increase in activity with an increase in detector angle from zero degrees to 75 degrees. At detector angles above 75 degrees, the activity decreased because of source positioning effects. For the present study, we measured the geometry correction factors for a shielded detector (2-in lead) at a detector angle of 45 degrees to be 0.63 + 0.06 at 662 keV and 0.58 + 0.06 at 334 keV. These values agree, within errors, with the estimate value of 0.7 + 0.1 for a previous study for 280 keV - 510 keV gamma rays at a detector angle of 45 degrees.