High-resolution High-purity Germanium Detector Research Articles

Effect of crystal structure on K shell binding energy of lead, mercury and tungsten using bremsstrahlung radiation

The K shell binding energies of lead, mercury, and tungsten in their pure elemental form and in some of their compounds have been measured for the first time by adopting a novel method. The method involves a weak beta source, an external bremsstrahlung converter, element and compound targets, and a high-resolution, high-purity germanium detector coupled to 16K multichannel analyzer. Continuous external bremsstrahlung photons produced by the interaction of beta particles from a 90Sr-90Y radioactive source with an iron foil are allowed to pass through the elemental and compound targets of lead, mercury, and tungsten. The spectrum of transmitted external bremsstrahlung photons is measured with a high-resolution high purity germanium detector spectrometer. The transmitted spectrum shows a sudden drop in intensity at K shell binding energy of the target. Such a sudden drop, which is due to the onset of the K shell photoelectric effect, has been used to determine the K shell binding energies. It has been investigated that the shifts in the K shell binding energies due to chemical environment of lead, mercury, and tungsten atoms is attributed to crystal structure.

Evaluation of Natural Radionuclide content in Nile River Sediments and Excess Lifetime Cancer Risk Associated with Gamma Radiation

Introduction: This Study has was carried out to measure and detect the natural occurred radionuclide content including 226Ra, 232Th and 40K in the Nile River sediments at various locations in Upper Egypt, from Aswan to El-Minya. Additionally, we determine the absorbed dose rate, the annual effective dose equivalent, and excess lifetime cancer risk also has been calculated. Material and Methods: The gamma ray measurements were performed with a high resolution High-Purity Germanium detector, low background, and Personal Computer multichannel analyzer. Results: In Aswan Governorate, the mean specific activities of radionuclide's (226Ra,232Th and 40K) 14.86, 13.78 and 175.4 in Bq/kg respectively. In Qena Governorate, the mean specific activities of mentioned radionuclides were 14.44 Bq/kg, 15.02 Bq/kg and 197.57 Bq/kg, respectively. These values were18.53 Bq/kg, 11.3 Bq/kg and 184.73 Bq/kg in Sohag Governorate, respectively. In Asyut Governorate the mean specific activities of the radionuclide's were 11.38 Bq/kg, 10.0 Bq/kg, and 164.715 Bq/kg, respectively. However, these values were 19.56 Bq/kg, 11.72 Bq/kg, and 239.92 Bq/kg in Minya Governorate, respectively. The hazard indices of gamma radiation such as Absorbed dose rate, annual effective dose equivalent and excess lifetime cancer risk were calculated. Conclusion: According to the results, all the values were within the reported values by the United Nations Scientific Committee on the Effects of Atomic Radiation. In addition, there was no likelihood of radiological health hazards to the population living close to the Nile river.

Radioactive artificial 137Cs and natural 40K activity in 21 edible mushrooms of the genus Boletus species from SW China

This study, for the first time, presents the results of activity concentration determinations for 137Cs and 40K in a high number (21 species, 87 composite samples, and 807 fruiting bodies) of mushrooms of the genus Boletus from across Yunnan in 2011–2014 and Sichuan (Boletus tomentipes) using high-resolution high-purity germanium detector. Activity concentrations of 137Cs demonstrated some variability and range from <4.4 to 83 ± 3 Bq kg−1 dry biomass in caps and from <3.8 to 37 ± 3 Bq kg−1 dry biomass in stipes, and of 40K, respectively, from 420 ± 41 to 1300 ± 110 and from 520 ± 61 to 1300 ± 140 Bq kg−1 dry biomass. No significant variations were observed regarding 137Cs and 40K activity concentrations among the same Boletus species from different sampling sites. No activity concentrations from 134Cs were detected in any mushrooms. Internal dose rates estimated were from intake of 1 kg of mushrooms per annum for 137Cs range for species and regions from around <0.0031 to 0.047 ± 0.003 μSv, while those for 40K were from around 0.22 ± 0.04 to 1.2 ± 0.1 μSv. The overall intake of 137Cs was low since low contamination was found in Boletus species.

Ground-state and isomeric-state cross sections for the 165Ho(n,2n) 164Ho reaction from reaction threshold to 20 MeV

By using the activation technique, the cross section for the reaction Ho($n$,2$n$) Ho was measured at two neutron energies of 13.5 and 14.8 MeV to resolve inconsistencies in the existing database. The 94- and 91.39-keV \ensuremath{\gamma} rays from the decay of the Ho${}^{m}$ isomeric state and Ho${}^{g}$ ground state, respectively, were recorded with a high-resolution high-purity germanium detector. The monoenergetic neutron beam was produced via the H($d$,$n$) He reaction. The cross sections also were estimated with the talys-1.4 nuclear model code that uses different level-density options at neutron energies that vary from the reaction threshold to 20 MeV. Results are also discussed and are compared with some corresponding values found in the literature.

Effect of the natural radioactivity concentrations and 226Ra/238U disequilibrium on cancer diseases in Penang, Malaysia

Natural radioactivity measurements and assessment of radiological hazards in soil and sand samples obtained from Penang, Malaysia were carried out using the Exploranium GR-135 Plus “Identifier” Radioisotope Identification Device and high-resolution High Purity Germanium (HPGe) detector system. The activity concentrations of 238U, 226Ra, 232Th, and 40K were found to be 184±11, 396±22, 165±14, and 835±28Bqkg−1 respectively, and the external gamma dose rate is 315±44nGyh−1 for soil samples. For sand samples, the activity concentrations of 238U, 226Ra, 232Th and 40K were 31±8, 62±16, 36±6, and 369±17Bqkg−1, respectively, and the external gamma dose rate is 66±12nGyh−1. To assess the radiological hazard of radioactivity present in the samples, the radium equivalent activity, annual effective dose, annual gonadal dose equivalent, external hazard, and internal indices were calculated.The Raeq values of soil samples were higher than the limit of 370Bqkg−1, which is equivalent to a gamma dose of 1.5mSvyr−1, whereas the Raeq for sand samples was lower than 370Bqkg−1. The calculated concentrations by HPGe spectroscopy were compared with the measured concentrations detected by a GR-135 spectrometer. The calculated and measured gamma dose rates had an ideal correlation coefficient R of 0.72. The gamma dose rates in Penang increased with the average annual age-standardized rates (ASR) for all cancers between 1994 and 2010. The effects of the pH value of soil and sand samples on natural radionuclides concentrations were investigated. The high concentration of 226Ra/238U ratio disequilibrium (226Ra/238U of 1.76–2.33) was observed in the sampling sites. Moreover, a portable continuous radon monitor (SNC, model 1029, Sun Nuclear Corporation) was used to measure the radon concentration of the soil surface. The radon concentrations were found to vary from 7 to 50Bqm−3. A positive correlation was observed between the radon and radium concentrations in samples measured by the SNC continuous radon monitor and HPGe detector.

Dispersion corrections to the forward Rayleigh scattering amplitudes of tantalum, mercury and lead derived using photon interaction cross sections

Dispersion corrections to the forward Rayleigh scattering amplitudes of tantalum, mercury and lead in the photon energy range 24–136keV have been determined by a numerical evaluation of the dispersion integral that relates them through optical theorem to the photo effect cross sections. The photo effect cross sections have been extracted by subtracting the coherent and incoherent scattering contribution from the measured total attenuation cross section, using high-resolution high-purity germanium detector in a narrow beam good geometry set up. The real part of the dispersion correction to which the relativistic corrections calculated by Kissel and Pratt (S-matrix approach) or Creagh and McAuley (multipole corrections) have been included are in better agreement with the available theoretical values.