High Doses Of Gamma Rays Research Articles

Exploring the effects of the alkaline earth metal cations on the electronic structure, photostability and radiation hardness of lead halide perovskites

The growing interest to the application of perovskite solar cells (PSC) in aerospace requires great attention to the design of new absorber materials with enhanced photostability and radiation hardness. We addressed this challenge through the B-site engineering by partial replacing of Pb2+ in the complex halides with Ca2+, Sr2+, and Ba2+. Change in the material electronic properties suggests the incorporation of the substituent cations in the perovskite lattice. However, when the loading of alkaline earth halides is high, they tend to segregate to the film surface and grain boundaries. The modification of MAPbI3 and Cs0.12FA0.88PbI3 by replacing a 1% of Pb2+ with alkaline earth metal cations resulted in improvements in the photostability and radiation hardness under exposure to gamma rays and electrons beam. Depending on the material formulation, it was possible to mitigate the photochemical and radiation-induced Pb0 formation and the univalent cation phase segregation. The best of the designed perovskite absorbers could successfully tolerate high doses of gamma rays (5.5 MGy) and electron fluences (3 × 1016 e/cm2), thus outperforming significantly the non-modified material. These findings feature the incorporation of alkaline earth metal cations as a promising approach for the development of PSC with enhanced radiation hardness for aerospace applications.

An account of chromosomal damage in PMCs of stripe rust infected barley

A study, on the effects of natural mild fungal infection on meiosis of Barley Pollen Mother Cells (PMCs), was done in order to analyze the chromosomal damage elicited by the pathogenic conditions. A pattern similar to common mutagens, of reduction in mitotic index and chiasma frequency, as well as, production of various aberrations that demonstrate chromosomal damage, was observed. The most common abnormalities were un-orientation and other spindle related aberrations, as well as stickiness and clumping of chromosomes. The disease induced a reduction in pollen viability as compared to the control plants. The results were compared with those of a high dose of a known mutagen ie gamma rays in order to draw commonalities between the two conditions.

INVESTIGATION OF DOSIMETRIC PROPERTIES OF TABLE SUGAR IRRADIATED WITH GAMMA RAYS USING EPR TECHNIQUE

In our study, it was observed that the EPR signals of table sugar irradiated with gamma rays at 3 kGy, 5 kGy, 10 kGy increased in proportion to the increasing dose. The fading in the signals was investigated by taking into account the peak-to-peak heights (Ipp) in the EPR spectra of table sugar. The stability of radicals was monitored by performing EPR measurements on sugar samples irradiated with high doses of gamma rays (Co-60) on 29.06.2020, 23.03.2021, 28.06.2021, 05.08.2021. Suitability evaluation was made with Z score, which is a statistical test to determine fading. It was observed that there was almost no loss in the EPR signals of sugar for 14 months.
 Also table sugar; Similarities have been shown by comparing the EPR spectra of the fruits used in the TS EN 13708 Foodstuffs - Standard for determining whether foodstuffs containing crystal sugars are irradiated by ESR spectroscopy. Thanks to these similarities, it has been suggested that fruits can also be used as dosimeters, depending on the sugar they contain.

Effects of high-dose gamma-ray irradiation on an In0.53Ga0.47As high electron mobility transistor

We investigate the effects of gamma-ray (γ-ray) irradiation on an In0.53Ga0.47As high electron mobility transistor (HEMT). After γ-ray radiation, the irradiated HEMT shows degradation of the maximum transconductance (g m,max ), the unity current gain cutoff frequency (f T ), and the maximum oscillation frequency (f max)—about 12.8%, 18.0%, and 16.9%, respectively—because of an increase in on-resistance (Ron) in In0.53Ga0.47As HEMTs exposed to high-dose γ-ray radiation. Moreover, we obtain a minimum noise figure (NFmin) of about 1 dB from 8 to 40 GHz for the irradiated HEMT, which is a lower value compared to a non-irradiated HEMT; this is because the gate leakage current is reduced after γ-ray irradiation.

Fabrication of slag/CKD one-mix geopolymer cement reinforced by low-cost nano-particles, mechanical behavior and durability performance

CKD is a byproduct of the cement industry, and its accumulation in the surrounding represents one of many issues associated with this industry. In this study, CKD was utilized in the fabrication of one-mix geopolymer cement (GP) composite as an economical and environmental solution for disposal of this byproduct. The mechanical properties and durability behavior during various deterioration actions were inspected. The obtained findings demonstrated that, replacing slag by CKD in the fabricated GP could cause an elongation in the setting times and reduction in the compression strength of approximately 50%. However, GPs containing CKD offered an accepted resistance to irradiation by γ-rays and to firing action. Reinforcing the GPs with nano Fe3O4 (NF) or nano TiO2 (NT) accelerated the geopolymerization reaction and offered mechanical properties surprising the control mix, this was related to the micro-filling and catalytic actions of the NPs which supported the formation of symmetrical and organized clusters of CSHs and CASH gel as shown in SEM micrographs. The reinforcing mixes surpassing the control mix in the protection against intrusion of sulfate ions which they could retain about 92% of their strength after 4 months of exposure while the control mix retained 80%. Furthermore, they showed a superior resistance to the destructive effect of irradiation by high dose gamma rays up to 1500 kGy and they retained ~ 75% of their strength after irradiation while the control mix was kept at only 35%. The fabricated composites are recommended for usage in many applied construction fields.

Effect gamma irradiation on structural properties of lithium zinc phosphate glass doped with MoO3

The new glasses with the chemical formula 45 P2O5 – 25 ZnO – (30-x) Li2O – xMoO3 (where x = 1,3,5, and 7 in mol%) have been fabricated using the melt quenching method. The amorphous nature was not changes before and after gamma irradiation by X-ray diffraction. The effect of gamma radiation (60Co) with the dose rate of 20k Gray on different properties of glasses has been studied. The Raman spectra were recorded between 400 and 4000 cm−1 wave number range to study the structural variation of the sample. The intensity of the Raman spectra is increases and peaks are shifted towards to left due to structural disorder. Intensity of the photoluminescence spectra emission at 287 nm and 390 nm and the excited at 240 nm wavelengths decreases after gamma irradiation. The obtained results confirms the shielding features of the glass when compared to other referenced glass material. The presently studied glass is excellently stable and can withstand high gamma ray doses and these glasses are suitable for radiation applications.

Mechanical Properties, Radiation Resistance Performances, and Mechanism Insights of Nitrile Butadiene Rubber Irradiated with High-Dose Gamma Rays.

The radiation effect of materials is very important and directly related to the safety and reliability of nuclear reactors. Polymer materials, one of the indispensable materials in nuclear power equipment, must withstand the ordeal of high-energy ionizing rays. In this work, through screening different γ-ray dose irradiation conditions, we systematically and comprehensively study the changes in the structure and properties of nitrile butadiene rubber (NBR) before and after γ-ray static irradiation at a high dose rate, and master the rule and mechanism of the γ-ray static irradiation effect of these polymer materials. The mapping relationship between the macroscopic properties, microstructure, and irradiation dose of NBR is accurately characterized. With an increase in total irradiation dose, the C=C double bond reaction occurs, and the C≡N bond, C=C, and C=O participate in the hyper crosslinking reaction. The glass transition temperature (Tg) increases with the cumulative irradiation amount. With the increased total irradiation amount, the degree of rubber cross-linking increases, causing an increased crystallinity and decomposition temperature. A growing amount of gamma irradiation causes the mechanical properties of the rubber to degrade simultaneously, increasing the shore hardness while decreasing the tensile strength and ultimate elongation at break. When the cumulative amount reaches 1 MGy, the ultimate elongation at break decreases significantly. A cumulative dose of radiation resistance of 4 MGy can be achieved by the samples. This work can provide theoretical and experimental support for the long-term stability of nitrile butadiene rubber and its derivatives in nuclear radiation fields and space radiation conditions.

Radiolytic degradation of cellulosic materials in nuclear waste: Effect of oxygen and absorbed dose

Lignocellulosic materials can be found in a significant fraction of the current low- and intermediate-level radioactive waste. During storage and disposal, radiolytic degradation of such materials can be expected, under oxic or anoxic conditions. This degradation may lead to a significant gas production and changes in the physico-chemical properties of the lignocellulosic materials, which can affect the formation of the known radionuclide-complexing agent isosaccharinic acid (ISA) as well as other (possibly complexing) degradation products during disposal. Hence, in the present work the radiolytic degradation of cellulosic tissues – realistically found in radioactive waste – was investigated under various storage and disposal conditions. For this, cellulosic tissues were exposed to γ-irradiation in gas-tight containers under oxic or anoxic conditions, at an absorbed dose ranging up to 1.4 MGy and at two different dose rates. Our results show that mainly H2, CO and CO2 are produced during irradiation of tissues, though also small amounts of CH4 are formed. The presence of oxygen does not affect the generation of H2, but results in a significant increase in the yields of CO, CO2 and CH4. Furthermore, radiation-induced chain scission is observed, causing a decreasing polymerization degree with increasing absorbed dose. Amorphization of the cellulose microstructure occurs significantly at high doses of gamma rays (≥ 0.8 MGy). An increase in the concentration of reducing functional groups is observed with increasing absorbed doses as well. For irradiation under anoxic conditions, this increase is correlated with the observed chain scission. In contrast, additional oxidation processes occur when irradiating cellulosic tissues in the presence of oxygen, resulting in a partially oxidized polymer backbone without causing considerably more chain scission or amorphization. These radiolytic changes to the cellulose structure, both under anoxic and oxic conditions, may enhance its hydrolytic degradation under the hyper-alkaline conditions of long-term final disposal, resulting in a faster production of radionuclide-complexing agents.

Field assessment of yield and its contributing traits in cowpea treated with lower, intermediate, and higher doses of gamma rays and sodium azide.

Across the globe, plant breeders of different organizations are working in collaboration to bring preferred traits to crops of economic importance. Among the traits, "high yielding potential" is the most important as it is directly associated with food security and nutrition, one of the sustainable development goals. The Food and Agriculture Organization acknowledges plant breeders' role and efforts in achieving local and global food security and nutrition. Recognizing the importance of pulses and increasing pressure on food security, the United Nations General Assembly declared 2016 the "International year of Pulses" owing to their preferred traits such as climate change resilience, wide adaptability, low agriculture input, and protein- and nutrient-rich crops. Keeping all these developments in consideration, we initiated an induced mutagenesis program by treating cowpea (Vigna unguiculata L. Walp.) with different doses of gamma rays and sodium azide aiming to enhance the yielding potential of an otherwise outstanding variety viz., Gomati VU-89 and Pusa-578. We noticed a substantial increase in mean values of agronomic traits in putative mutants raised from seeds treated with lower and intermediate doses of mutagens. Statistical analysis such as correlation, path, hierarchical clustering analysis (HCA), and principal component analysis (PCA) were used to assess the difference between mutagenized and control populations. A significant and positive correlation of yield with yield-attributing traits was recorded. However, among all the yield attributing traits, seeds per pod (SPP) depicted the maximum direct impact upon yield, and therefore, working on this trait may yield better results. A widely used PCA revealed 40.46% and 33.47% of the total variation for var. Gomati VU-89 and var. Pusa-578, respectively. Cluster analysis clustered treated and control populations into separate clusters with variable cluster sizes. Cluster V in the variety Gomati VU-89 and cluster V and VI in the variety Pusa 578 comprised of putative mutants were higher yielding and hence could be recommended for selection in future breeding programs. We expect to release such mutant lines for farmer cultivation in Northern parts of India depending on the performance of such high-yielding mutant lines at multilocations.

Gamma-ray induced effect on the structural and optical properties and durability of neodymium-doped zinc–bismuth–borotellurite glasses and glass ceramics

This study explores the effect of gamma rays on a new glass and glass–ceramic 10ZnO–34.5B2O3–34.5TeO2–20Bi2O3–1Nd2O3. The samples were exposed to different gamma-ray doses of 2.5, 10, and 50 kGy. The impact of gamma-ray irradiation was investigated using different physicochemical methods. The X-ray diffraction (XRD) results for glass samples show that the amorphous nature did not change before and after irradiation, and a shift in the main peak along with a change in the unit cell volume with increasing doses was observed in glass-ceramic matrix. The Fourier transform infrared (FTIR) and Raman spectra (IR) for the glass samples show change in intensity without variation in the band position. The 50 kGy dose hid a high wavenumber peak in the FTIR and Raman spectra for the glass–ceramic sample, indicating a significant change in the glass–ceramic matrix. The reduction in the band gap energy for the glass samples confirms the FTIR results. The durability of the glass samples was gradually enhanced by increasing the dose up to 10 kGy. The up-conversion photoluminescence in the glass samples exhibits an emission peak at 525 nm that decreases in intensity as the dose increases. The mean free path results confirm the shielding features of the glass when compared to other reference glass materials. The results show that the glass is excellently stable and can withstand high gamma-ray doses, making it suitable for radiation applications.

Fabrication and characterization of high-resolution 4H-SiC epitaxial radiation detectors for challenging reactor dosimetry environments

Reactor dosimetry environments require radiation detectors that are capable of operating at high temperatures in extremely high neutron and gamma-ray dose rates. Silicon carbide (SiC) is one of the most promising wide bandgap semiconductors (3.27 eV) for harsh environment applications due to its radiation hardness, high breakdown voltage, high electron saturation velocity, and high thermal conductivity. In this paper, we summarize the prospect of Schottky barrier radiation detectors, fabricated on highly crystalline low-defect detector-grade n-type 4H-SiC epitaxial layers with thickness ranging from 20 to 250 lm, for harsh environment applications. A comprehensive discussion on the characterization of the parameters that influence the energy resolution has been included. The usage of electrical and radiation spectroscopic measurements for characterizing the junction and rectification properties, minority carrier diffusion lengths, and energy resolution has been elaborated. Characterization of crucial factors that limit the energy resolution of the detectors such as charge trap centers using thermally stimulated transient techniques is summarized. Finally, the effect of neutron fluence on the performance of the 4H-SiC detectors is discussed.

Integrated 4H-SiC Photosensors With Active Pixel Sensor-Type Circuits for MGy-Class Radiation Hardened CMOS UV Image Sensor

For radiation-hardened CMOS image sensor (CIS), 4H-SiC photosensors with active pixel sensor (APS)-type circuits were developed and demonstrated. The dark current of 4H-SiC photodiodes was <2 nA/cm2. The spectral sensitivity characteristics were also evaluated in the wavelength from 200 nm to 400 nm. The maximal quantum efficiency was 63% at 270 nm. The photosensors with APS type circuits showed high responses to UV light, demonstrating their operation. High gamma-ray dose experiments were also carried out. The dark current after 2 MGy (SiO2) irradiation was 25 nA/cm2. The photosensors with APS-type were successfully working after 2 MGy exposure.

INFLUENCE OF IONIZING RADIATION ON THE DIFFUSE REFLECTION SPECTRA OF STEATITE CERAMICS SNC

In this article, the radiation defects induced in steatite ceramics type- SNC- irradiated with high doses of gamma-rays of 60Co source and mixed reactor nо-gamma-irradiation were studied using optical spectroscopy, i.e. diffuse reflection method. An analysis of the results of the diffuse reflection spectra showed that some structural defects are formed under gamma-irradiation. These are oxygen vacancies, unbound oxygen atoms, and E1 -centers (a three-coordinated silicon atom that has captured an electron) in the ultraviolet region of the spectrum. In the visible region of the spectrum, the types of hole centers are different. After decomposing the spectrum of the visible region into Gaussians, it was found that in this region of the spectrum, with no –gamma- irradiation of the reactor, in comparison with gamma-irradiation, various types of hole centers - (O-Me, Me-metal) are additionally formed. The efficiency of creating these structural defects in nо-gamma-reactor irradiated samples was higher compared to gamma irradiated samples.

Horticultural Performance of Field Grown Somaclones and Irradiated Strawberry (Fragaria × Ananassa Duch.)Variants

In the present investigation horticultural performances of field grown somaclones and gamma irradiated strawberry were studied. The somaclones performed better with regard to vegetative and reproductive characters while axillary buds irradiated with lower dose of gamma rays (10 and 30 Gy) were more vigorous in terms of number of leaves and petiole length. Whereasaxillary buds irradiated with higher dose of gamma rays (50 and 60 Gy) showed abnormal fruit development, reduced growth, small leaf area and fruit size. A total of six variants were obtained on screening the somaclones and irradiated plantlets on the basis of phenotypic characters, fruiting characters and Single Sequence Repeat (SSR) markers. The frequency of variants was higher (3.22%) in soamclones than in irradiated plants (2.75%) obtained from axillary buds. These finding would be helpful in providing a powerful technological tool for the improvement of clonally propagated crops. Bangladesh J. Bot. 51(3): 555-563, 2022 (September)

Nucleic acids and melanin pigments after exposure to high doses of gamma rays: a biosignature robustness test

AbstractThe question about the stability of certain biomolecules is directly connected to the life-detection missions aiming to search for past or present life beyond Earth. The extreme conditions experienced on extraterrestrial planet surface (e.g. Mars), characterized by ionizing and non-ionizing radiation, CO2-atmosphere and reactive species, may destroy the hypothetical traces of life. In this context, the study of the biomolecules behaviour after ionizing radiation exposure could provide support for the onboard instrumentation and data interpretation of the life exploration missions on other planets. Here, as a part of STARLIFE campaign, we investigated the effects of gamma rays on two classes of fungal biomolecules–nucleic acids and melanin pigments – considered as promising biosignatures to search for during the ‘in situ life-detection’ missions beyond Earth.

Impact effect of gamma irradiation on the optical, FTIR, ESR spectral properties and thermal behavior of some mixed (PbO + Bi2O3) borate glasses searching for shielding effects

Four borate glasses with mixed and equal heavy metal oxides PbO+Bi2O3 ranging from 70→55% were prepared by routine melting and annealing technique. These glasses were selected to identify the effects of gamma irradiation on glasses combining two heavy metal oxides (PbO, and Bi2O3) which are known to be of shielding nature towards irradiation. Collective measurements of the optical, structural FTIR and ESR. spectral properties of the prepared equal mixed glasses were carried out before and after a relatively high dose of gamma rays (6 M rad). Optical spectra of the glasses reveal before irradiation strong UV absorption due to trace ferric ions present as impurities in the chemicals used for the preparation of the glasses. After irradiation, an extra small induced near-visible band at 420 nm has been identified and is attributed to the creation of an induced boron- oxygen hole center (BOHC) or nonbridging oxygen hole center (NBOHC). FTIR spectra reveal distinct vibrational bands due to triangular (BO3 groups) and tetrahedral (BO4 groups) within their variant characteristic wavenumbers. Also, the condensed intensities of the FTIR bands refer to the sharing of vibrations due to PbO or BiO within their specific sites as evidenced by the deconvoluted spectra. Gamma irradiation causes no variations on the FTIR and ESR spectra confirming the shielding effect of the heavy metal oxides present in mixed percentages.

Silicon Carbide Neutron Detectors for Harsh Nuclear Environments: A Review of the State of the Art

Silicon carbide (SiC) semiconductor is an ideal material for solid-state nuclear radiation detectors to be used in high-temperature, high-radiation environments. Such harsh environments are typically encountered in nuclear reactor measurement locations as well as high-level radioactive waste and/or “hot” dismantling–decommissioning operations. In the present fleet of commercial nuclear reactors, temperatures in excess of 300 °C are often encountered, and temperatures up to 800 °C are anticipated in advanced reactor designs. The wide bandgap for SiC (3.27 eV) compared to more widely used semiconductors such as silicon (1.12 eV at room temperature) has allowed low-noise measurements to be carried out at temperatures up to 700 °C. The concentration of thermally induced charge carriers in SiC at 700 °C is about four orders of magnitude less than that of silicon at room temperature. Furthermore, SiC radiation detectors have been demonstrated to be much more resistant to the effects of radiation-induced damage than more conventional semiconductors, such as silicon, germanium, or cadmium zinc telluride (CZT), and have been demonstrated to be operational after extremely high gamma-ray, neutron, and charged-particle doses. The purpose of the present review is to provide an updated state of the art for SiC neutron detectors and to explore their applications in harsh high-temperature, high-radiation nuclear reactor applications. Conclusions related to the current state-of-the-art of SiC neutron detectors will be presented, and specific ideal applications will be discussed.

PHYSICAL QUALITY OF GAMMA RAYS-IRRADIATED MEATBALL STORED AT ROOM TEMPERATURE

This study was aimed to investigate the meatballs physical qualities that are irradiated with high-doses of gamma rays. This study used the irradiation method with the dosage of 20, 25 and 35 kGy and storage at room temperature. For the control (0 kGy), storage was done in the freezer. The results showed that at 0 month, the samples water contents at 20; 25; 35 kGy were 67,03%; 67,50%; 66,67%, with significant difference (p&lt;0.05) to control 68,73%. Water content (%) at 2 months were 65,03%; 66.00%; 67.50% and control 63,23% 2 months has significant difference (p&lt;0.05) but still meet the SNI standard (&lt;70%). Optimum water activity was obtained at irradiation dose of 35 kGy. The pH results doses of 20; 25; 35 kGy for 0 month were 6,35; 6,34; 6,39 and 2 months were 6,59; 6,47; 6,46, respectively. pH of control was 5,87 at 0 month and 6,49 at 2 months. The pH of samples stored for 0 month were relatively higher than the control pH. At 2-month storage, the pH of the samples was lower than the control, but still meets the standard. Meatball irradiation up to 35 kGy can be used as an alternative for preservation at room temperature.

Effects of gamma radiations on morphological and physiological traits of finger millet (Eleusine coracana (L.) Gaertn.)

The present study was carried out to analyse the effect of gamma radiation on morpho-physiological parameters of seven days old M1 seedlings of Eleusine coracana (L.) Gaertn. (finger millet). The finger millet seeds were irradiated with different doses of viz., 100 Gy, 200 Gy, 300 Gy, 400 Gy, 500 Gy, 600 Gy, 700 Gy, 800 Gy, 900 Gy and 1000 Gy of gamma ray. Higher doses of gamma rays induced substantial reduction in mean performance of morphological and physiological traits. However, lower doses showed stimulatory effects on morphological and physiological traits. The results revealed a progressive decrease in chlorophyll fluorescence with increasing dose of gamma irradiation. Among all the mutagen doses used, 600 Gy gamma irradiated seeds showed enhanced mean performance of morphological and physiological traits in finger millet. Hence 600 Gy gamma rays may be employed in other crop species to improve the agro-economic traits

Gamma rays induced morphological, flowering and palynological modifications in horse gram (Macrotyloma uniflorum)

Aim: The quest was framed to analyse the effect of high dose of gamma rays on morphological, flowering, and palynological traits in horse gram (Macrotyloma uniflorum). Methodology: Two horse gram varieties PAIYUR 2 and CRIDA 1-18 R were mutated using 32 mutagenic combinations. Sterile plants produced by gamma rays: 400 Gy were utilized to study the alterations in morphological, flowering characters in 20 randomly selected plants, and palynological traits using scanning electron microscope. Results: Gamma rays (GR):400 Gy produced sterile plants with altered ideotype and reproductive traits. It reduced expression of yield attributing traits, delayed first flowering, modified anther, and pollen size. The palynological changes included genotype dependant variation in pili number, size and exine ornamentation. Interpretation: High gamma ray dose is lethal to horse gram which was evidenced through grave modifications in morphological and palynological traits. These alterations resulted in sterility. Sterile plants tried to repair the irradiation induced damages and hence failed to perform routine reproductive functions.