Radioactivity is a natural part of our environment. Ionizing radiation from radioactive materials can affect the life cycle of organisms; sometimes increase the rate of transition between cycle leading to the proliferation of cells as seen in some cancer cells or delay the rate of transition between cell cycle. A NaI detector is essential to determine the activity of a radioactive material. To determine the resolution of NaI detector and the efficiency of the geometry used for this experiment, quality control was done for NaI detector using 22Na reference source. The efficiency of the detector was used to verify the activity of 65Zn sample source which was used to irradiate Drosophila melanogaster. The dose rate at points close to 65Zn was calculated and also measured using thermoluminescent dosimeters. The cumulative average dose over the tubes containing fruit flies was also evaluated. It was discovered that both the resolution and efficiency of the detector decreases with the increase in photon energy. The detector resolution was found to be 13 ± 1 % at 511 keV, and 6.92 ± 0.04 at 1275 keV. At 511 keV the efficiency was 0.02 and at 1275 keV, the efficiency was 0.00712. The calculated and experimental values of 65Zn activity were 38.33 MBq and 37.36 MBq respectively, with 2.5 % difference. At 2 cm and 10 cm away from 65Zn, the measured and calculated dose rates were very close with 3.7 % and 1.8 % differences. The percentage difference in the dose rates from online radprocalculator and experimental values at 2 cm and 10 cm were 35 % and 26.6 % respectively. The average dose to all generations of fruit flies was 160 ±10 rad. The activity of 65Zn calculated using the detector’s efficiency value was very close to the value calculated using the manufacturer’s value. The online radprocalculator should be reviewed to accommodate for X-rays from the radioactive samples for points close to the sample. An investigation into the gene expression and inquiries into physical and behavioral changes, life span, and resistance to stress of the offspring of the irradiated flies should be done.


Andrew Roberts

Committee Member

Analía Dall’Asén

Committee Member

Daniel Toma

Date of Degree




Document Type



Master of Science (MS)


Physics and Astronomy


Science, Engineering and Technology

Included in

Nuclear Commons



Rights Statement

In Copyright