Figure 3. the mean spectra at different test positions
Figure 4. the total counts of the spectra at different test positions
From figure 3, we noticed that the characteristic peak of Cs-137 located
at the channels between 240 and 290. The difference between background
spectra and source contained spectra became obvious until the 100-s mean
spectra were acquired. From figure 4, due to the statistic fluctuations,
the total counts of source contained spectra and background spectra were
located in overlap range, especially the source contained spectra were
collected at the low-dose rate positions. Therefore, it is hard to
discern them based on the total counts. Figure 7 showed typical 1-s
spectra at different test positions.