the goal of this work to determine the counting effectiveness of  NaI(Tl) 2x2 well detector that is scintillationCanberra Inc.) .The advantageous asset of this type detector  its high effectiveness that used to determination the lower degree of radiation as  normal occurring radioactive material NORM.The  gamma attenuation coefficients  of normal  radioisotopes and its own daughters had been determined to get the three aspects of counting  effectiveness as shown in (Table 1). The (dining table 2) presents the values of t he efficiencies which are counting plotted the graph due to the fact purpose of this research..

Keywords effectiveness, attenuation, coefficients, gamma ray, NORM.