High-purity Germanium Detector Research Articles

Natural Radionuclides Concentrations and Associated Radiation Hazard of Some Building Rocks Used in Taiz City, Yemen

Building materials comprise a diverse range of natural rocks that contain varying mineral components including radionuclides. Gamma spectrometry-based high-purity Germanium detectors were utilized to measure the activity concentrations of natural radionuclides: Radium-226 (226Ra), Thorium-232 (232Th), and Potassium-40 (40K) in various building rock samples found within and surrounding Taiz city. The activity concentrations of 226Ra, 232Th, and 40K vary from 27.79 ± 0.77 to 234.49 ± 3.13 Bq.kg-1, 25.82 ± 0.40 to 415.31 ± 2.47 Bq.kg-1, and 457.91±2.61 to 1139.56 ± 5.43 Bq.kg-1 with overall average value of 71.55 Bq.kg-1, 93.87 Bq.kg-1, 966.88 Bq.kg-1 respectively, these values were higher than the permissible thresholds. Furthermore, several radiation hazard indices were estimated including the radium equivalent (Raeq), the external hazard index (Hex), the internal hazard index (Hin), the gamma level index (Iɤ), the dose rate(Dɤ), the annual effective dose equivalent (AEDE), the excess lifetime cancer risk (ELCR), and the annual gonadal dose equivalent (AGDE). The findings illustrated that Basalt rocks have the minimum values of radiation hazard indices while the Himatite rocks have the maximum values of radiation hazard. The average values of radiation risks for most of building rocks fall below the recommended limits for safety. Based on the Radiation hazard indices of building rock samples, it can be concluded that with the exception of hematite rocks, all the examined rocks are considered safe for use in construction materials and pose non-significant radiation risks. The awareness about natural radioactivity levels of building rocks is critical for planning and performing strategies in radiation safety of buildings.

Modeling of N and P-Type of Coaxial Ge Detectors Using MCNPX and the Effect of Dead Layer Variation on Its Response Function

Abstract This study assessed the response function of a p-type and n-type coaxial high-purity germanium (HPGe) detector via Monte Carlo N-Particle eXtended (MCNPX). MCNPX was employed to model the Coaxial Ge detectors, and for a precise simulation, the dimensions of the dead layer of germanium crystals were added. The dead layer was separated into front and lateral surfaces, and the thickness of each dead layer was modeled. In this work, the simulated detectors have been performed at different energy lines using a radioactive source Eu-152 to study the response function of each with dead layer variations for the front dead layer and study the range of relative deviation of the Monte Carlo simulation outputs from the manufactured declared data. The results proved that the n-type coaxial HPGe detector is more sensitive to the dead layer change than the p-type with a thick change of 0.01 mm. This research has significant effects on the efficiencies of the radiation detection systems in the energy range ∼ (120–1410) keV.

Nondestructive determination of isotopic abundance using multi-energy nuclear resonance fluorescence driven by laser Compton scattering source

We report on the quantitative nondestructive analysis of the natural isotopic abundances of hafnium and tungsten elements using nuclear resonance fluorescence. Metallic samples of hafnium and tungsten were irradiated to six quasi-monochromatic γ-ray beams generated by laser Compton scattering in the energy range of 2.4–3.2 MeV. Multiple nuclei were simultaneously excited at each of the six γ-ray beam energies. A high-purity germanium detector array detected deexcitations of the nuclei. In total, 51 transitions were unprecedentedly employed to estimate the isotopic abundances of heavy elements nondestructively. The estimated abundances of three hafnium isotopes and three tungsten isotopes are consistent with standard known natural abundances within the experimental uncertainties. The deviation from the standard values ranges from 0.18% to 1.36%.

Half-life determination of the ground state decay of 167Tm and 168Tm

Precise determination of half-lives of 167Tm and 168Tm are important for their application in nuclear medicine diagnostics, nuclear forensics, and other nuclear data measurements. We produced 167Tm and 168Tm sources using an α-particle beam bombarded 165Ho target and a series purification steps. A series of 173 measurements was performed over a period of 44 days using a high-purity germanium (HPGe) detector to track the count rate change as a function of time by following the 207.8 keV and 531.5 keV γ-lines to determine the radioactive decay half-life of 167Tm. The measurement of half-life of 168Tm ground state has been performed using the same HPGe γ-ray spectrometer to observe γ-lines at 198.3 keV, 816.0 keV, 184.3 keV, 741.4 keV and 914.9 keV. Weighted least-squares fits of exponential decay curves were performed for the dataset of each γ-ray emission, with final determined half-lives of 9.250(15) d and 93.41(12) d for 167Tm and 168Tm, respectively. The uncertainty budgets are presented and discussed in detail. Our result of 167Tm half-life is consistent with the Evaluated Nuclear Structure Data File (ENSDF) recommended half-life of 9.25(2) d. The outcome of 168Tm half-life determination is longer than the ENSDF recommended half-life of 93.1(2) d. Further independent measurements would be ideal to resolve the discrepancy.

Investigation of natural and artificial radioactivity levels in travertines of the Cappadocia region in Turkey.

This study determined natural and artificial radionuclide concentrations to evaluate natural radioactivity and health risk levels of nine travertines in the Yaprakhisar and Balkayası regions in Turkey. The samples coded B1-M, B2, B5, B7, B8, and B10 represent waste derived from the Yaprakhisar travertines, as well as samples T5-M, T12, and Z1 travertines derived from Balkayası. The levels of natural and artificial radionuclide concentrations (232Th, 40K, and 137Cs) were measured using a high-purity germanium (HpGe) detector system. The travertine activity ranged from 2.09 to 12.07Bqkg-1 for 232Th, 4.21 to 13.41Bqkg-1 for 40K, and 0.42-3.26Bqkg-1 for 137Cs. The results showed that the activity concentration values for 232Th, 40K, and 137Cs were coherent with the travertine analysis results in the UNSCEAR, 2000; 2008 publications. The values obtained were lower than the average values in the UNSEAR reports. The radiological hazard parameters calculated in this study were absorbed gamma dose rate (D), radium equivalent activity (Raeq), annual gonadal dose equivalent (AGDE), exposure dose (ER), total annual effective dose (AEDEtotal), excess lifetime cancer risk (ELCRtotal), gamma representative level (GRL), internal hazard index (Hin) and external hazard index (Hex).

A comprehensive study of the shielding ability from ionizing radiation of different mortars using iron filings and bismuth oxide

The current work discusses the radiation attenuation capability and different shielding characteristics of different mortar samples. The samples were prepared by replacing different percentages of fine aggregate with iron filling and replacing different percentages of hydrated lime with Bi2O3 (0–50 wt.%). The prepared mortar samples are coded as CHBFX where X = 0, 10, 30, and 50 wt.%. The mass and linear attenuation coefficient was determined experimentally using a narrow beam technique, where a high purity germanium detector, and different point gamma-ray sources (such as Am-241, Cs-137, and Co-60). The linear attenuation coefficient was also calculated using the Monte-Carlo simulation code and the online Phy-X/PSD software. The comparison of the three methods showed a good agreement in the results. The linear attenuation coefficient drops from 19.821 to 0.053 cm−1 for CHBF0, from 27.496 to 0.057 cm−1 for CHBF10, from 42.351 to 0.064 cm−1 for CHBF30, and from 55.068 to 0.071 cm−1 for CHBF50 at photon energy range from 0.015 to 15 MeV. The half-value layer thickness, tenth-value layer thickness, and mean free path of the prepared mortar composites were also calculated photon energy ranged from 0.015 to 15 MeV. The fast neutron removal cross-section of the prepared CHBFX mortar samples have values of 0.096 cm−1, 0.098 cm−1, 0.103 cm−1, and 0.107 cm−1 for the mortar samples CHBF0, CHBF10, CHBF30, and CHBF50, respectively. The results showed that the mortar sample with the highest iron filing concentration, CHBF50, provides the best protection against gamma rays and fast neutrons which could be used in the nuclear and medical fields.

Estimation of 241Am and 239Pu activity embedded in the tissue using portable planar HPGe detector.

This paper describes a procedure for the estimation of 241Am and 239Pu activity present in the human tissue by measuring the depth of contaminant using a portable Planar High Purity Germanium detector (HPGe). The ratios of photopeak counts of X-rays or gammas obtained with the detector coupled to collimator are calculated for the estimation of depth of the contaminant and the optimum one is determined. Since Minimum Detectable Activities (MDA) for the detector coupled to a collimator are higher than that of bare detector, activity must be estimated using bare detector, after locating the contaminant. Two methods are described for the estimation of plutonium coexisting with 241Am: (i) Abundance and isotopic correction for 239Pu (ii) and 239Pu:241Am ratio. The procedure to estimate 239Pu when plutonium isotopes alone are present is also established. An optimum monitoring period to detect the minimum value of intake for both radionuclides corresponding to chelation therapy and excision is also derived.

Design of high-light-collection-efficiency optical fiber for germanium detectors immersed in liquid argon

The implementation of Slicon Photon-Multipliers (SiPMs) wave-length shifting (WLS) fibers light response system in liquid argon (LAr) is a promising technology for suppressing background in rare event experiments. Moreover, it is particularly relevant for experiments that utilize high-purity germanium (HPGe) detectors directly operated in LAr, such as the direct detection of dark matter and neutrinoless double beta decay. In this work, we exhibit a designed WLS fiber for the LAr detector, verify the feasibility of the manufacturing technology, and simulation research about its light collection performance. The novel fiber incorporates two materials, styrene and 1,1,4,4-tetraphenyl-1,3-butadiene (TPB). The pre-experiments proved that the fiber has good WLS and light-conducting properties for ultraviolet light. In addition, the effect of different light collection methods on detection efficiency was assessed by Geant4 simulation. Our results show that adding optical fibers can significantly increase light collection efficiency. Compared with the design of TPB coating with commercial fiber, the new structure of WLS fiber can improve the light collection efficiency by 50%. The simulation results indicate that the new fiber structure can enhance the light collection efficiency of the LAr detection system, thereby improving the anti-coincidence system's performance in rare event experiments.

Evaluation of radioactivity and radiological parameters in soil samples in Isparta, Türkiye

In the city centre of Isparta, located in the southwestern part of Türkiye, indoor radon concentrations and gamma dose rate levels were observed above the world and country averages. For this reason, the determination of the natural radioactivity levels in soil samples of Isparta province is of great interest. In the present study, the activity concentrations of radionuclides (namely 226Ra,232Th, 40K and 137Cs) were investigated in the soil samples collected from 72 different points including the city centre and 12 towns of Isparta by using a gamma spectrometer with a high-purity germanium (HPGe) detector. The activity concentrations of 226Ra,232Th, 40K and 137Cs radionuclides in the samples were found in the range of 4.08 ± 0.39–69.84 ± 1.43 Bqkg−1, 2.63 ± 0.28–65.66 ± 1.41 Bqkg−1, 44.48 ± 3.17–452.38 ± 9.65 Bqkg−1 and 0.28 ± 0.18–19.10 ± 0.61 Bqkg−1 respectively. The averages of all the measurements were determined as 15.69 ± 0.72 Bqkg−1 for 226Ra, 15.40 ± 0.78 Bqkg−1 for 232Th, 210.60 ± 6.22 Bqkg−1 for 40K and 3.44 ± 0.31 Bqkg−1 for 137Cs. Although these values were below the country and world averages, it was revealed that the 226Ra and 232Th activity concentrations in the city centre exceeded the national and world averages. In addition, radiological risk maps of the analysed radionuclides were produced for the first time, covering all towns within the Isparta province. To evaluate the radiological hazards resulting from natural radionuclides, external hazard index (Hex), absorbed dose rate (D), annual effective dose equivalent (AEDE), male and female lifetime cancer risk (LCR) values were also calculated. The outcomes of this study revealed that all the radiological parameter averages for Isparta were lower than the world and country averages but the calculation results for the city centre displayed the opposite of this situation except for the external hazard index.

Evaluation of radioactivity concentration in farm fresh milk and concomitant dose to consumer

In this study, activity concentrations of natural radionuclides in 28 raw milk samples collected from different dairy farms in Dhaka city of Bangladesh were measured using a high-purity germanium (HPGe) detector for the first time. The activity concentration of 226Ra, 232Th, and 40K in the investigated fresh milk samples ranged from BDL (Below detection level) to 26 ± 1.6 Bq/kg, BDL to 11.7 ± 3.3 Bq/kg and 101 ± 17 to 384 ± 32 Bq/kg, respectively. No artificial radionuclides were found in the investigated samples. Present results show inline within the range of available data in the literature. Annual committed effective doses were estimated following the consumption characteristics of raw milk by city population, values are found within the limiting range recommended by international organizations due to consumption of foodstuffs. Additionally, real-time gamma-ray dose rate in the farms/sampling locations was found in the range of 0.12 ± 0.01–0.20 ± 0.01 μSv/h by using a digital gamma survey meter (Gamma Scout) and the calculated maximum annual effective dose due to outdoor absorbed dose was found to be 0.25 mSv/y, which shows lower than the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) recommended limit of 2.4 mSv/y. This study indicates that the concentration of radionuclides in the farm fresh milk of Dhaka city does not pose any unwanted risk to public health, and it is safe to consume by both children and adults with the current intake level.

Experimental burn-up analysis of ITU Triga Mark II reactor fuel elements

In this study, burn-up values ​​of spent fuels were determined using Non-Destructive Analysis (NDA) with the help of 137Cs burn-up indicator. Four spent fuel elements (F30, D18, B5 and E14) that burned in the core of the Istanbul Technical University Triga Mark II research reactor over the years were investigated with two different methods. In addition, the individual activity of the fuel elements along the axial fuel length was determined by the High Purity Germanium (HPGe) detector. As expected, it was determined that the fuel element B5, located in the center of the reactor core, exhibited the highest burn-up value with both methods. The calculations conducted using method 1 revealed a burn-up rate of 205.59 MWd/tHM for the B5 fuel element, while method 2 yielded a burn-up value of 5.40%. Experimental results were compared with previous simulation burn-up studies.

Prototyping a High Purity Germanium cryogenic veto system for a bolometric detection experiment

The use of High Purity Germanium detectors operated in ionization mode at cryogenic temperatures is investigated as an external background mitigation solution for bolometers used in rare-event search experiments. A simple experimental setup, running a 52-g Li2WO4 bolometer sandwiched in-between two 2-cm thick High Purity Germanium cylindrical detectors in a dry cryostat, shows promising rejection to environmental gammas and atmospheric muons backgrounds. The acquired data are used together with a Monte Carlo simulation of the setup to extract the main contributions to the external backgrounds expected in an above ground experiment, such as e.g. current and future experimental efforts targeting the detection of coherent elastic neutrino-nucleus scattering at reactor facilities. Based on all these results, a 4π coverage similar veto system achieving a O(10 keV) energy threshold is expected to achieve a ≳73% and a ≳92% rejection power for gamma-like and muon-like events, respectively.

Heavy metals and radionuclides in Islamabad's industrial area: A comprehensive analysis of soil and water pollution, source apportionment and health effects using statistical and geospatial tools

IntroductionHeavy metal pollution in industrial areas around the world is a significant problem that is worsening day by day. Heavy and toxic metals are detrimental to human health and ecology in a region. Hence, determining their level and potential is critical to form effective pollution control strategies for reducing the risks associated with them. Study areaIslamabad is the capital city of Pakistan with a dedicated industrial zone. PurposeThis study evaluated the heavy metal pollution levels in the soil and water of Islamabad's industrial area and radionuclides activity in the soil using statistical, geospatial tools as well as their subsequent health and ecological hazards. Materials and methodsElemental analysis in this study was performed using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The radionuclides activity in the soil was quantified using High Purity Germanium Detector (HPGe). ResultsThe soil of Islamabad's industrial area is highly polluted with heavy and toxic metals. The risk posed by heavy metals to the eco-system was calculated using Ecological risk factor and was found to be above recommended level. Principal component analysis (PCA), Pearson's correlation and inverse distance weighting interpolation (IDW) revealed that the soil near the steel mills, landfill and marble processing plants is extremely polluted with heavy metals. Health hazards from heavy metal exposure through ingestion, inhalation, and dermal contact were also calculated. Cr posed a carcinogenic risk to children via the three exposure pathways with the value being 4 × 10−4. Natural radioactivity levels for Ra-226, Th-232 and K-40 were found to be 25.96±12.50, 15.84±2.59, 469.48±52.38 Bqkg−1, respectively. Elemental analysis of water samples coupled with geospatial analysis showed that water samples collected near the industrial complexes have elevated levels of Sb. The water quality for irrigation was assessed and the water from Islamabad's industrial area was found to be suitable for irrigation. ConclusionIn conclusion, the soil of Islamabad's industrial area is highly polluted with heavy metals and has lower levels of natural radioactivity. The water near the industries also has elevated levels of some heavy metals.

Geochemical characteristics, hazards impact assessment and radiogenic heat production of the alkaline rocks.

This study primarily investigates the natural radioactivity level in alkaline rocks collected from the Wadi El-Dib ring complex (WDRC) in North Eastern Desert of Egypt, and assesses potential health risks associated with their use as decorative building materials. The work was accomplished using a high-purity germanium detector as well as ICP-MS and ICP-AES techniques. The WDRC composed essentially of trachyte, quartz syenite, granite and syenite. Geochemically, these rocks contain high SiO2 and alkalis with metaluminous to slightly peraluminous features. All rocks contain high concentrations of rare earth elements (∑REEs = 109-1075ppm), with clear enrichment in light REEs compared to heavy REEs [(La/Yb)N = 8.3-25.3. Radiometrically, the concentrations of the natural radioisotopes (238U, 232Th, and 40K) in the studied rock types surpassed the worldwide average values assigned for building materials by UNSCEAR. This elevation of the radioisotope concentration values is due to the presence of supplement minerals such as monazite, zircon, allanite, and rutile. Granites exhibit the highest mean concentrations of 238U (av. 164.24 ± 14.76Bq/kg) and 232Th (av. 214.37 ± 23.33Bq/kg), while trachytes demonstrate the highest 40K (av. 1352.56 ± 65.56Bq/kg) concentrations. In contrast, syenites exhibite the lowest mean concentrations for 238U (av. 54.51 ± 6.81Bq/kg) and 232Th (av. 56.76 ± 6.25Bq/kg), while quartz syenites display the lowest mean concentration of 40K (av. 1144.78 ± 96.19Bq/kg). The radiogenic heat production (RHP) associated with U, Th, and K range between 1.41 to 9.33μW/m3, exceeding the typical crustal mean value of 0.8 to 1.2μW/m3. The radiological parameters and indices evaluating risks of the outdoor and indoor radiation doses due to the investigated rocks were assessed. The results indicated that these rocks meet globally accepted values and safety standards (approved by UNSCEAR, ICRP, and EC) for surface building materials, as well as they underscore the importance of adhering to safety protocols to safeguard workers from radiation exposure within the WDRC area. Ultimately, the data herein provide a valuable database for assessing the compatibility of geochemical data and natural radioactivity level in WDRC rocks. Additionally, it reveals that from the radiological perspective, the investigated rocks are considered safe for use as decorative construction materials.

Radon exhalation and health hazard assessment for various ceramic tiles used in Bangladesh

Objective: Among various building materials, tiles are the most used decorative materials used worldwide. For the safe use of tiles at home and workplace it is required to select them properly based on radiation dose due to radon and gamma emission.
 Experiments: Among various tiles available in the market, 25 different types of tiles were collected for this experiment. Collected tiles are then ground and stored in sealed cans for secular equilibrium. To measure gamma activity due to the radionuclides 226Ra, 232Th, 40K, High Purity Germanium (HPGe) detector was used. To store radon gas emitting from tiles, a big box was used. The activity concentration was then measured by a radon detector (RadonEye) by placing it inside the box.
 Results and discussion: It was observed that 226Ra, 232Th, 40K activity varies from 45 – 89 Bq/Kg, 77 – 110 Bq/Kg, and 321 – 694 Bq/Kg. The radium equivalent activity varies from 198.32 – 280.46 Bq/Kg, less than the recommended value of 370 Bq/Kg set by UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation). The activity concentration of radon varies from 31 – 71 Bq/m3. This is lower than the 300 Bq/m3 recommended by ICRP (International Commission on Radiological Protection). The radon exhalation rate varies from 0.179 – 0.409 Bqm−2h−1. To assess radiological hazards associated with the tiles samples air absorbed dose rate, internal and external hazard index, gamma index, annual indoor and outdoor effective dose rate, and dose due to radon were also calculated.
 Conclusion: Though the estimated values for external and internal hazards are below the recommended values, they may be safe for adults. As children have thinner skin and breathe more air due to high breathing frequency, they may receive more radiation than adults. Moreover, they are at a greater risk because of their developing bodies and long life expectancy post-exposure.

High-purity germanium semiconductor modeling in the detector response function toolkit

We have extended the detector response function toolkit (DRiFT) to provide modeling capabilities of semiconductor sensors. DRiFT provides realistic nuclear instrumentation response by post-processing Monte-Carlo N-particle (MCNP®) radiation transport outputs. MCNP® is capable of modeling radiation transport in complex environments, but has limited detector physics and readout electronics modeling capabilities. Semiconductor detector response can be calculated with a high-fidelity for a flexible range of environments by utilizing MCNP® to simulate radiation interactions inside of detector volumes, and then using DRiFT to model charge transport and signal formation in the semiconductor, as well as the readout electronics. DRiFT models charge transport in the semiconductor, the preamplifier, shaping amplifier, pulse pile-up, and electronic noise to generate detector response. The semiconductor application in DRiFT can model a range of semiconductor materials, shapes, and sizes; and is demonstrated here for a large volume coaxial high-purity germanium (HPGe) detector. Here, we compare detector response functions of a coaxial HPGe detector with measurement of 60Co, 133Ba, and 137Cs at varying count rates, and we conduct a parameter study to demonstrate the effect of changing parameters in the DRiFT simulation. The HPGe detector response function shows excellent agreement with measurements of difference sources with varying dead times and count rates.

Radiological Assessment and Potential Health Risks of Tailings from Komu, Southwestern Nigeria

There are reports that radionuclides found in mining tailings pose significant challenges to the natural environment and cause health risks to humans. The study investigated the levels of activity concentrations of 226Ra, 232Th and 40K radionuclides, as well as radiological hazard indices in tailings sourced from Komu, a community emblematic of mining activities in the Southwest of Nigeria. Thirty (30) tailing samples were collected and analysed by a High-purity Germanium (HpGe) detector. The results revealed high activity concentrations of these radionuclides exceeding global averages and indicating potential health risks. The activity concentration of 226Ra ranged between 312.07 and 851.14 Bq/kg, with an average of 652.86 Bq/kg. Similarly, the activity concentration of 232Th ranged between 33.31 and 160.10 Bq/kg, with an average of 116.26 Bq/kg. In addition, the activity concentration of 40K ranged between 96.11 and 1184.65 Bq/kg, with an average of 717.53 Bq/kg. The radiological hazard indices considered in this study exceeded the internationally accepted safety limit for building construction materials. These findings indicate heightened exposure risks, emphasizing the need for regulatory measures to mitigate hazards associated with tailings sourced from Komu, particularly for building construction purposes.

Experimental Study to Determine the Backscattering, Asymmetry, and Tailing Factors for Some Elements in the Atomic Number Range of 4≤Z≤48 at 59.54 keV Using the Gamma Backscattering Method

This experimental study has been carried out by using gamma backscattering method which is a non-destructive method. Some elements which are in the atomic number range of 4≤Z≤48 have been used as backscatterer samples to investigate the variation of backscattering factor, asymmetry factor, and tailing factor with atomic number. These samples were irradiated by γ-rays of 59.54 keV energy emitted from a 10 μCi 241Am point radioactive source. To count the backscattered photons from samples, a high purity germanium detector (HPGe) with a resolution of 182 eV at 5.9 keV and active area of 200 mm2 was used. It was concluded that the count rate and backscattering factor increased with increasing atomic number, but the coherent to backscattering ratio, asymmetry factor, and tailing factor decreased.

Radioisotope production using lasers: From basic science to applications

The discovery of chirped pulse amplification has led to great improvements in laser technology, enabling energetic laser beams to be compressed to pulse durations of tens of femtoseconds and focused to a few micrometers. Protons with energies of tens of MeV can be accelerated using, for instance, target normal sheath acceleration and focused on secondary targets. Under such conditions, nuclear reactions can occur, with the production of radioisotopes suitable for medical application. The use of high-repetition lasers to produce such isotopes is competitive with conventional methods mostly based on accelerators. In this paper, we study the production of 67Cu, 63Zn, 18F, and 11C, which are currently used in positron emission tomography and other applications. At the same time, we study the reactions 10B(p,α)7Be and 70Zn(p,4n)67Ga to put further constraints on the proton distributions at different angles, as well as the reaction 11B(p,α)8Be relevant for energy production. The experiment was performed at the 1 PW laser facility at Vega III in Salamanca, Spain. Angular distributions of radioisotopes in the forward (with respect to the laser direction) and backward directions were measured using a high purity germanium detector. Our results are in reasonable agreement with numerical estimates obtained following the approach of Kimura and Bonasera [Nucl. Instrum. Methods Phys. Res., Sect. A 637, 164–170 (2011)].

Evaluation of Radioactivity Levels in Soil Samples from Assosa City in Benishangul Gumuz Region, Ethiopia

The specific activity concentrations of naturally occurring radionuclides in soil samples collected from suburban areas of Assosa City was measured using a High purity Germanium (HPGe) detector. The average specific activity concentrations of 238U and 232Th exceed the recommended safe value of 35.0 and 30.0 Bq kg−1, respectively. For 40K, the average activity concentration is below the recommended safe value of 400.0 Bq kg−1. The calculated mean value of the absorbed dose rate is 72.8 ± 3.72 nGy h−1 which exceed the recommended safe value of 59 nGy h−1. The calculated mean annual effective dose equivalent values for indoor and outdoor are 2.11 ± 0.1 mSv y−1 and 0.52 ± 0.02 mSv y−1, respectively. The calculated mean values of the internal hazard index, external hazard index, and gamma index are 0.43 ± 0.013, 0.56 ± 0.01, and 0.5 ± 0.01, respectively, and those values are below the recommended safe value of one. The mean value of excessive lifetime cancer risk is above the threshold value of 0.29 × 10−3. From this study, it is recommended that Assosa soil needs further investigations.