High Purity Germanium Gamma Spectrometry Research Articles

Ingestion dose due to 226Ra, 228Ra, and 40K in the plant origin food materials grown around BARC, Visakhapatnam

Naturally occurring radionuclides of uranium, thorium series, and potassium are significant contributors of ingestion dose. Radioactive concentrations of 226Ra, 228Ra, and 40K in plant origin food cultivated around BARC, Visakhapatnam, were determined and the assessment of the ingestion dose through food consumption to different groups of population was estimated. Radionuclides in the samples analyzed were measured by high purity germanium gamma spectrometry system. The estimated annual effective dose from the ingestion of cereals, pulses, vegetables, fruits, and leafy vegetables due to 226Ra, 228Ra, and 40K radionuclides is 0.32 mSv. In this paper the estimated annual effective dose in the study area is compared to the ingestion dose due to intake of different food materials by various natural radionuclides reported in various parts of India and world. The data generated will be a useful baseline studies for the upcoming BARC facilities at Visakhapatnam, India.

Monte Carlo simulation of HPGe gamma‐spectrometry systems

In order to obtain the relationship between energy and channel, the suitable radionuclides are chosen to calibrate. The result shows a goodness of fitting. The Monte Carlo simulation about the detection efficiency of the high purity germanium (HPGe) gamma-spectrometry system was performed. The distance between radioactive source and the end cap is set 15, 20, 25 and 50 cm, respectively. The maximum absolute efficiency locates at around 80 keV. It can be concluded that the absolute efficiency is declining accompany with the increasing of distance. In the end, at the distance of 25 cm, the authors changed thickness of the dead layer and the source distribution to calculate. The maximum absolute efficiency is 8.56E−03, and the relative deviation is 0.0011. Then it was compared with the experimental result provided with the manufacturer. The result of simulation shows a certain agreement with the experimental results. This work will be helpful for calculating the efficiency of HPGe gamma-spectrometry.

Radionuclide determination and radioactivity evaluation of surface soil samples collected along the Erçek Lake basin in eastern Anatolia, Turkey

In the present study, the mean activity concentrations of 238U, 232Th, 40K and fission products 137Cs in the soil samples measured by using high-purity germanium gamma spectrometry were 18.9, 27.2, 524.0 and 10.6Bqkg−1, respectively. The activity results were analyzed for frequency distribution, tabulated and compared with Turkey and worldwide literatures. Radiological risk evaluation was done by calculating absorbed gamma dose rate in outdoor air and the corresponding annual effective dose due to external exposure to radionuclides distributed in soil. The mean values of the outdoor gamma dose rates and the external annual effective doses received by members of the public from terrestrial radiation and 137Cs were estimated at 47 nGy h−1 and 0.6 nGy h−1 and 57.7μSv and 1.2μSv, respectively.

Natural radioactivity measurements in building materials used in Samsun, Turkey

In this study, radioactivity levels of 35 different samples of 11 commonly used building materials in Samsun were measured by using a gamma spectrometry system. The analysis carried out with the high purity Germanium gamma spectrometry system. Radioactivity concentrations of (226)Ra, (232)Th and (40)K range from 6 to 54 Bq kg(-1), 5 to 88 Bq kg(-1) and 6 to 1070 Bq kg(-1), respectively. From these results, radium equivalent activities, gamma indexes, absorbed dose rates and annual effective doses were calculated for all samples. Obtained results were compared with the available data, and it was concluded that all the investigated materials did not have radiological risk.

Performance of HPGe gamma spectrometry system for the measurement of low level radioactivity

Comprehensive quality assurance/quality control procedure is very much necessary to obtain accurate and precise analytical measurement result. This paper discusses the quality control aspects of the High-Purity Germanium (HPGe) based gamma spectrometry system, which has been used for the measurement of low-level radioactivity in environmental samples. The gamma spectrometry system consisting of coaxial n-type HPGe detector having 50% relative efficiency with respect to 7.62 cm x 7.62 cm NaI (Tl), Nuclear Instrumentation Module (NIM) based pulse processing electronic accessories and 8 k MCA. To reduce the background contribution, 7.5 cm thick lead has been placed surrounding the detector. The minimum detectable activities (MDA) with 95% confidence level (for 300 g soil sample and 100,000 s counting time) for important radionuclides such as 238U, 226Ra, 232Th, 40K, and 137Cs are 10.4, 4.3, 4.1, 16.9 and 0.1 Bq kg−1, respectively. The Quality control (X bar R) charts were plotted using 137Cs and 40K background counts observed periodically, which showed that the fluctuation is well within the confidence limit and confirms the stability of the system. The laboratory has been participating in the proficiency tests (PTs) of the International Atomic Energy Agency (IAEA). In recently concluded PTs, the samples include soil, spiked standard solution, spinach, phosphogypsum and spiked air filter were analysed for the natural, fission and activation products radionuclides. The performance evaluation of the IAEA PTs showed that the laboratory results were in good agreement with the target value, which confirms the reliability and traceability of the gamma spectrometric measurement result of the laboratory.

Natural and artificial radionuclide measurements and radioactivity assessment of soil samples in eastern Sichuan province (China)

The activity concentrations of natural and artificial radionuclides were measured in the eastern region of Sichuan province (China). One hundred and ninety-three soil samples from this region were collected and analysed by high-purity germanium gamma spectrometry. The measured results show that the average radioactivity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs in the soil samples are 26, 49, 440 and 6 Bq kg(-1), respectively. The calculated average radium equivalent activity is 130 Bq kg(-1), which is less than the recommended limit of 370 Bq kg(-1). The absorbed dose rate and annual effective dose are 60 nGy h(-1) and 74 µSv, respectively. This is the first time the absorbed dose rate in the east region of Sichuan has been mapped. Overall, the environmental radiation background is greater in the southern part of the area studied than in the northern.