Abstract: Accurate timing alignment and stability is important
to maximize the true counts and minimize the random counts in
positron emission tomography So signals output from detectors must
be centering with the two isotopes to pre-operation and fed signals
into four units of pulse-processing units, each unit can accept up to
eight inputs. The dual source computed tomography consist two units
on the left for 15 detector signals of Cs-137 isotope and two units on
the right are for 15 detectors signals of Co-60 isotope. The gamma
spectrum consisting of either single or multiple photo peaks. This
allows for the use of energy discrimination electronic hardware
associated with the data acquisition system to acquire photon counts
data with a specific energy, even if poor energy resolution detectors
are used. This also helps to avoid counting of the Compton scatter
counts especially if a single discrete gamma photo peak is emitted by
the source as in the case of Cs-137. In this study the polyenergetic
version of the alternating minimization algorithm is applied to the
dual energy gamma computed tomography problem.
Abstract: The amounts of radioactivity in the igneous rocks
have been investigated; samples were collected from the total of eight
basalt rock types in the northeastern of Kurdistan region/Iraq. The
activity concentration of 226Ra (238U) series, 228Ac (232Th) series, 40K
and 137Cs were measured using Planar HPGe and NaI(Tl) detectors.
Along the study area the radium equivalent activities Raeq in Bq/Kg
of samples under investigation were found in the range of 22.16 to
77.31 Bq/Kg with an average value of 44.8 Bq/Kg, this value is much
below the internationally accepted value of 370 Bq/Kg. To estimate
the health effects of this natural radioactive composition, the average
values of absorbed gamma dose rate D (55 nGyh-1), Indoor and
outdoor annual effective dose rates Eied (0.11 mSvy-1) . and Eoed
(0.03 mSvy-1), External hazard index Hex (0.138) and internal hazard
index Hin(0.154), and representative level index Iγr (0.386) have been
calculated and found to be lower than the worldwide average values.