The study has been carried out to measure the activity concentration of natural and anthropogenic radionuclides in fifteen(15) soil samples of Natore, Kushtia and Pabna district, which are around the 30 km peripheral area of Rooppur Nuclear Power Plant, by gamma ray spectrometry system using a High Purity Germanium (HPGe) detector. It is found that the activity concentration of 226 Ra, in the collected sample was from 3.52 Bq/kg to 28.5 Bq/kg with the average value of 12.42 Bq/kg. For 232 Th, the range was from 4.18 Bq/kg to 34.5 Bq/kg with the average value of 12.6 Bq/kg. Finally, the activity concentration of 40 K, in the collected sample was in the range of 84 Bq/kg to 345 Bq/kg, and the average value was 198.9 Bq/kg. The absorbed dose rate (D) was found to be in the range of 4.59 nGy/h to 40.93 nGy/h with the mean value 21.3 nGy/h. The annual effective dose (E) was in the range of 0.006 mSv/yr to 0.152 mSv/yr with an average of 0.033 mSv/yr. The radium equivalent activity was in the range from 10.02 Bq/kg to 89 Bq/kg with an average of 44.99 Bq/kg. The external hazard index (Hex) was found to be in the range of 0.027 to 0.242 with the mean value of 0.121 and the internal hazard index (Hin) was found to be in the range of 0.044 to 0.302 with the mean value of 0.156. All the values are much below the recommended limit by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), 35 Bq/kg for 226 Ra, 30 Bq/kg for 232 Th and 400 Bq/kg for 40 K. According to international and national regulation, the annual dose to members of the public, 1and Hex & Hin must be lower than unity. Moreover, no artificial radioactivity was found in the soil samples of this study area. This research concludes that the found values are within the permissible limits as required by the Nuclear Safety and Radiation Control(NSRC) Rules-1997 of Bangladesh and International Atomic Energy Agency(IAEA) Safety Standards-General Safety Requirements (GSR): Part-3.

Enhancement of light absorption in solar cell presents a strong challenge to its overall performance. We analyzed an Organic Solar Cell (OSC) with Photonic Crystal (PC) structure using Finite Difference Time Domain (FDTD) method. Aluminum oxide (Al2O3) has been used as photonic crystal structure and the lattice structure has been chosen to be hexagonal. Absorption enhancement has been observed by changing the height of the Hexagonal Lattice structure (HLS). When height is increased to 0.26 and radius to period ratio (r/a ratio) is set to 0.4, there is a significant increase of absorption in the middle wavelength region approximately from 463 nm to 575 nm and a significant decrease in lower wavelength. As the height is increased further, these changes in absorption begins to increase and at a certain value, these changes begin to reverse. Almost same phenomena occur when r/a ratio is 0.2 and 0.3 taken at approximately same height.

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Abstract-2D

In this research, the excellent parameter for regular Quality Control (QC) testing of intrinsic uniformity for dual-head Single Photon Emission Computed Tomography (SPECT) gamma camera is determined. The integral and differential intrinsic uniformity tests for both Useful Field Of View (UFOV) and Centre Field Of View (CFOV) were done by insertion a point-source of 99m Tc in front of the detectors with detached collimators to measure the effect of source to camera distance and a count rate on intrinsic uniformity. The result reveals that the best intrinsic uniformity image is obtained at source-to-camera distance of 3 m and a count rate between 16 and 60 M.