60Co Gamma Rays Research Articles

Assessment of mutagenic sensitivity in blackgram variety CO 6

The present study was conducted to examine the mutagenic effect of 60Co gamma rays and a combination of 60Co gamma rays with EMS in blackgram variety CO 6. Based on the LD50 dose, the seeds were treated with three different doses of gamma rays (200, 300, 400 Gy) and recurrent doses of 20 mM and 30 mM EMS were treated with gamma ray irradiated seeds for combination treatments. The M1 generation was evaluated in the field for the following parameters viz., germination percentage, plant survival percentage, plant height at 30 DAS and maturity, pollen fertility and seed fertility. A dose-dependent decrease was noticed for all the characters under this study in M1 generation. Overall, the maximum reduction was noticed at a higher dose of 400 Gy gamma rays and 400 Gy + 30 mM EMS mutagenic treatments. Among the mutagenic treatments, a combination of 60Co gamma ray + EMS exhibited the maximum effect with a higher percentage of reduction in all the traits while increased pollen sterility was found to be associated with a corresponding increase in dose/concentration of mutagenic agents. A significant positive correlation was observed between viable mutation frequency and biological damage caused by mutagens in M1 generation. Hence, the higher doses of 60Co gamma rays (300 and 400 Gy) and 60Co gamma rays +EMS (300 Gy+ 30; 400 Gy+ 20 and 400 Gy+ 30 mM) proved to be efficient in increasing the mutation frequency towards desirable directions. Key wordsBlackgram, combination treatment (60Co gamma rays + EMS), 60Co gamma rays, mutation breeding.

Differences in electrical responses and recovery of GaN p+n diodes on sapphire and freestanding GaN subjected to high dose 60Co gamma-ray irradiation

We investigate the effects of high-rate and high total doses of 60Co gamma rays on the current–voltage (IV) characteristics of GaN p+n diodes grown by metal-organic chemical vapor phase epitaxy on Ga-face (0001) sapphire and hydride vapor phase epitaxy freestanding GaN substrates. We show that diodes grown on sapphire undergo more permanent changes upon irradiation at doses up to 3900 kGy than those grown on freestanding GaN. By combining diode and circular transfer length method measurements, we show that the p-type contact interface and adjacent p++ Mg-doped layer are sensitive to irradiation. In initial experiments, diodes grown on sapphire exhibited p-type contacts with Schottky characteristics, while those on freestanding GaN were Ohmic. Serendipitously, we identified and subsequently irradiated a freestanding sample with a pre-irradiation spatial gradient of p-contact Schottky vs Ohmic behavior across the die. This sample allowed the root cause of induced change to be identified as differences in the p++ contacting layer. We show that the p-type contact's pre-irradiation Schottky behavior is predictive of diodes' IV characteristics changing significantly upon gamma-ray irradiation. Further, we observe that the IV curves of diodes on freestanding GaN recover fully over several weeks at room temperature to be indistinguishable from pre-irradiation. IV curves from diodes on sapphire do not fully recover; we thus hypothesize that interactions between radiation-induced point defects and threading dislocations affect the evolution of radiation damage.

Flexible, high sensitive and radiation-resistant pressure-sensing hydrogel

Excellent radiation resistance is a prerequisite for pressure-sensitive hydrogels to be used in high-energy radiation environments. In this work, tannic acid-modified boron nitride nanosheet (BNNS-TA) is first prepared as the radiation-resistant additive by a facile one-step ball milling of hexagonal boron nitride and tannic acid. Then, polyacrylamide (PAAm)-based pressure-sensitive hydrogel doped with BNNS-TA and Fe3+ ions is fabricated. The ternary BNNS-TA/Fe3+/PAAm hydrogel exhibits excellent compressive strength (at least four times the compressive strength of unfilled pure PAAm hydrogel), pressure-sensitive performance (gauge factor is up to 1.4), and performance recovery due to the combination of multiple intermolecular interactions, such as covalent crosslinking, hydrogen bonds, and ion coordination interactions. The BNNS-TA/Fe3+/PAAm hydrogel can be made as a pressure sensor installed in the control circuit or attached on the human body to detect human activities accurately. More importantly, the compressive strength and the pressure-sensitive performance of the BNNS-TA/Fe3+/PAAm hydrogel can be maintained after the hydrogel is irradiated by 60Co gamma-ray at an absorbed dose of 15 kGy. As a comparison, the compressive strength of the unfilled PAAm hydrogel is only a quarter of that before irradiation. This work not only reveals a facile method to achieve the preparation of chemically modified BNNS as a promising radiation-resistant additive but also provides a novel strategy for the development of pressure-sensitive hydrogel devices in radiation environments.

Dynamic Protective Effect of Chinese Herbal Prescription, Yiqi Jiedu Decoction, on Testis in Mice with Acute Radiation Injury.

Objective A Chinese herbal prescription, Yiqi Jiedu (YQJD) decoction, is used for injuries caused by radiotherapy. This study aimed to investigate the dynamic protective effects of YQJD decoction in mice on radiation damage at different time points of the testis. Methods The 200 male Balb/c mice were randomly divided into 5 groups (blank, model, Anduolin, low-dose YQJD, and high-dose YQJD groups). Blank and model groups were all given stomach deionized water. Anduolin group and high and low dose of Chinese herb groups were treated with Chinese material medical decoction compound for 2 weeks before being irradiated. Except for the blank group, other groups were given whole-body one-time irradiation of 5.5 Gy 60Co gamma rays. Histopathology examination of testes was conducted on the 1st, 7th, 21st, and 35th day after irradiation, respectively. Indexes of sperm motility rate, sperm count, serum levels of testosterone (T), estradiol (E2), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were also measured correspondingly. Result Compared to 1 day and 7 days after irradiation, most of the indexes, including testis index, sperm motility, and count, were decreased on the 21st and 35th day in all irradiated groups. However, compared with the model group, the indexes to assess sperm quality and the morphological structures of testis in low-dose and high-dose YQJD groups were significantly recovered on the 21st and 35th days. Additionally, reproductive hormones, including testosterone and estradiol, were recovered more in low-dose and high-dose YQJD groups on the 21st and 35th days. Conclusion The YQJD decoction is able to accelerate the recovery of sperm indexes, testosterone, and estradiol levels of sex hormones in mice after irradiation and demonstrated good protective effects on the testis.

Monte Carlo analyses of the fusion neutron and gamma signals from the chromium self-powered detector.

To test the applicability of self-powered detectors (SPDs) for radiation monitoring in fusion reactor blankets, several irradiation tests have been undertaken with the ad hoc designed Cr-SPD, which presents the novelty of using chromium as the emitter material. This detector was exposed to an intense 60Co gamma-ray source, and to the 14MeV neutrons produced by the D-T fusion reaction. Detailed analyses of the measured signals have been done here using a Monte Carlo modeling technique. We describe the simulations of the fusion neutron and gamma tests of the Cr-SPD, and compare their results with the experimental ones. Keeping in view the difficulty in computational reproduction of the sophisticated nuclear-electrical phenomena behind low-level SPD signals, our model is found to perform well, giving correct electrical polarities and orders of magnitude of the signals, as well as valuable insights into their different components. Our experience has highlighted the deficits and the needed improvements for the traditional SPD simulation techniques for prompt signal analyses.

Total Ionizing Dose Effects on Multistate HfOₓ-Based RRAM Synaptic Array

Emerging nonvolatile memories (eNVMs) have demonstrated satisfactory accuracy on various applications in deep learning. Characterized by high density and low leakage power consumption, resistive random access memory (RRAM) becomes very attractive in synaptic devices for deep neural networks (DNNs). RRAM-based synaptic devices include both analog and discrete versions. Unlike analog RRAM synapses which suffer from nonlinearity, discrete but multistate RRAM synapses are better suited for neural network hardware implementation. In this article, the multistate operation in RRAM arrays has been proposed as a synaptic device for DNN inference. Four-state conductance has been achieved in HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> -based RRAM synaptic arrays. The impact of total ionizing dose (TID) on the multistate behavior of HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> -based RRAM is investigated by irradiating a one-transistor-one-resistor (1T1R) 64-kb array with CMOS peripheral decoding circuitry fabricated at the 90-nm technology node with Co-60 gamma rays ( <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">60</sup> Co γ-ray irradiation).

Radiation-Induced Error Mitigation by Read-Retry Technique for MLC 3-D NAND Flash Memory

In this article, we have evaluated the Read-Retry (RR) functionality of the 3-D NAND chip of multilevel-cell (MLC) configuration after total ionization dose (TID) exposure. The RR function is typically offered in the high-density state-of-the-art NAND memory chips to recover data once the default memory read method fails to correct data with error correction codes (ECCs). In this work, we have applied the RR method on the irradiated 3-D NAND chip that was exposed with a Co-60 gamma-ray source for TID up to 50 krad (Si). Based on our experimental evaluation results, we have proposed an algorithm to efficiently implement the RR method to extend the radiation tolerance of the NAND memory chip. Our experimental evaluation shows that the RR method coupled with ECC can ensure data integrity of MLC 3-D NAND for TID up to 50 krad (Si).

Radiation Protection Effect of Protaetia Brevitarsis Larvae Extracts on Blood and Prostate in Male Rats Irradiated with Co-60 Gamma-ray

Radiation Protection Effect of Protaetia Brevitarsis Larvae Extracts on Blood and Prostate in Male Rats Irradiated with Co-60 Gamma-ray

DSC studies of the influence of gamma irradiation on the structural properties of the complexes formed with cetyl-trimethyl-ammonium bromide

The effect of irradiation carried out for potato starch on further transformations taking place in the starch-CTAB-water system (10:1:11) was studied using differential scanning calorimetry (DSC). Native solid starch and dense (25 wt%) starch gels were irradiated with 60Co gamma rays using doses in the range 1–30 kGy. DSC studies were carried out in heating-cooling-heating cycles (3 heating and 3 cooling cycles) with rates of 10 and 5 °C min-1. The differences were discovered between the amylose-lipid complex transition taking place in the case of the non-irradiated and the irradiated starch. The results are discussed in terms of modification the structural properties of the complex formed by the non-irradiated starch and the species irradiated using various doses. The structural changes were confirmed by FTIR spectroscopy and viscosity data. It can be concluded that the complexes formed using the irradiated starch have revealed decreased symmetry in comparison to the complex formed using the non-irradiated starch. In general, subsequent thermal treatment in the calorimeter induces further deterioration of the structure of the complex formed in the cases of the irradiated samples, while none or the opposite effect was noticed in the case of the non-irradiated starch. In the case of granular starch the changes of the complex structure were detected when the doses in the range 2–30 kGy were applied. Irradiation with a dose of 5 kGy causes easily noticeable modification of the complex.

Investigation of radiation-associated deformation in the electrical properties of metal-polymer semiconductor

In the present study, rubrene-based Schottky barrier structures have been formed by using the evaporation technique to investigate the conductance–voltage (G–V) and capacitance-voltage (C–V) values of the effect of the 60Co gamma-ray irradiation. The conductance and capacitance values were measured before and after 60Co gamma-ray radiation at 100 kHz, 500 kHz and 1 MHz. The frequency-dependent effects of interface state density and series resistance with and without irradiation in dark were analyzed at room temperature. The analysis results imply that values of forward and reverse C characteristics decrease the rate depending on gamma-ray irradiation and the increment of voltage due to the exchange of majority carriers between the majority carrier band of semiconductor and interface states. The irradiation dose and frequency increase show irradiation dispersion at the accumulation region when an A.C. signal is applied to the semiconductor structures. The G–V characteristics of rubrene-based Schottky barrier structures change with gamma radiation dose at different frequencies. Also, these characteristics relate to the density of the interface states. The analyses reveal that D it values decrease with the increase in frequency before 60Co gamma-ray irradiation. These values also decrease with the increase in frequency at the same radiation doses after 60Co gamma-ray irradiation. They decrease with the increase in irradiation doses at the same frequency, except for 100 kHz. Experimental results indicate that rubrene-based Schottky barrier structures can be altered using 60Co gamma-ray irradiation. The experimental contributions indicate a substantial step forward in the structure-function relationship in the benchmark organic semiconductors.

Optimization of gamma radiation dose for induction of mutations in okra

ABSTRACT Wide variability does not exist in okra [Abelmoschus esculentus (L.) Moench], requiring induction of genetic variability. Mutagenesis creates desired variability among genotypes without altering the agronomic base which is sometimes difficult to induce using other breeding methods. Seed germination/seedling emergence and seedling growth were evaluated under laboratory and field conditions by imposing 300 to 1000 Gy (Gray, the SI unit of radiation) gamma radiation to determine median lethal (LD50) and median growth reduction (GR50) doses with Co60gamma rays. The LD50 and GR50 doses varied for both growing conditions. More than 80% of seed exposed to the LD50 dose of gamma radiation in the laboratory did not emerge under field condition. The LD50 and GR50 doses of gamma radiation determined under field condition exhibited close correspondence and presented a reliable picture regarding lethality and injury in the M1 generation (the first generation from the irradiated seed). The R2 for the linear model for seedling emergence, shoot and root length, fresh and dry weight of seedlings under field condition were 0.908, 0.902, 0.911, 0.983 and 0.972, respectively. Determination of the LD50/GR50 is important to optimize the radiation dose to isolate desired utilizable mutants. Dose optimization should be determined through use of LD50 and GR50 under field condition. The gamma radiation dose between 350 Gy and 450 Gy was optimum to create desirable mutants in okra. The optimal dose could induce a higher rate of mutation with little biological damage in succeeding generations of okra.

The influence of electron and gamma irradiation on the properties of starch:PVA films – the effect of irradiation dose

Abstract The paper discusses the effect of ionizing radiation on the functional properties of the biodegradable starch:PVA films. The analysis is related to the possible use of the material for packing the products (particularly, food) that are predicted for radiation decontamination and to the potential modification of the material by radiation treatment. Our previous results have shown that the influence of ionizing radiation on the films’ properties varied for the specific compositions (differing in starch:PVA ratio or the type of substrates) and depended on irradiation conditions. However, these studies considered only the irradiation performed in gamma chamber or in e-beam using a dose of 25 kGy. Therefore, the present study deals with the effect of the irradiations performed using various doses on the selected promising starch:PVA composition. The films characterized by starch:PVA weight ratio of 45:55 was obtained by solution casting and irradiated with fast electrons in air and with 60Co gamma rays in nitrogen applying the doses of 5, 10, 20, 25, 30, 50, and 75 kGy. No regular dependence has been noticed between the composition of films (differing in the starch and PVA content) and the intensities of the particular bands in the UV-VIS DRS spectra after irradiation. The results indicated strong interaction of the starch and PVA components in the films and the occurrence of specific reactions in each composition upon irradiation. No special differences were observed between tensile strength and Young’s modulus of the non-irradiated films characterized by the starch:PVA ratio equal to 45:55 and the samples irradiated using doses in the range of 5–75 kGy. Similarly, no differences were observed in both cases between the swelling capability of the non-irradiated and the irradiated films. However, it can be deduced that solubility in water increased when the radiation dose increased. The results show that using the doses till the range 25 kGy does not cause an essential change of all the examined properties of the starch:PVA (45:55) films. Accordingly, starch:PVA (45:55) films might be considered suitable for packing food predicted for radiation decontamination.

Methyl thymol blue solution and film dosimeter for high dose measurements

A novel radio-chromic solutions and polyvinyl alcohol (PVA) films with different concentrations of methyl thymol blue (MTB) dye have been investigated and studied for high dose applications. The MTB dosimeters were exposed to irradiation using gamma ray 60Co source from 2.5 to 50 kGy for film, and from 0.10 to 2.5 kGy for solutions. The radio-chromic dosimeters were investigated using ultraviolet visible (UV–Vis) spectrophotometry. The effect of MTB dye concentration, relative humidity, and stability of the dosimeters were investigated. The results show that the dose response sensitivity of the dosimeters improved significantly with increasing the absorbed dose and MTB dye concentrations. The un-irradiated and irradiated dosimeters show a perfect stability for one week. Hence, these films can be used as dosimeters in industrial radiation processing. The study shows that the useful dose range is in the range of 2.5–20 kGy and 0.1–1.2 kGy, for film and solution dosimeters, respectively.

Gamma-Ray-Induced Error Pattern Analysis for MLC 3-D NAND Flash Memories

This article analyzes the data corruption pattern in the shared pages of multi-level cell (MLC) 3-D NAND memory under ionizing radiation from a Co-60 gamma-ray source for up to 20 krad(Si) dose. The results show that the radiation-induced error pattern between the shared pages follows a unique correlated behavior. We also find that the error locations within a given page remain uncorrelated, meaning that the occurrence of an error does not force a cluster of errors under ionizing radiation.

Dosimetric evaluation of the effect of dental restorative materials in head and neck radiotherapy.

The aim of our study is to assess the dose enhancement from scattered radiation due to dental restorative materials used for occlusal and mesio-occlusal-distal (MOD) cavity filling during simulated head and neck radiotherapy. We have studied the dose enhancement ratio (DER) of conventional amalgam, high-copper amalgam, and resin composite dental restorative materials at cadaver mandible teeth using 2 therapeutic photon energies of 1.25 MeV (Co-60 gamma ray) and 6 MV (Linac X-ray) for irradiation. DER values at buccal position for Co-60 and 6 MV X-ray were 1.250 ± 0.013 and 1.151 ± 0.012, respectively. For dental cavity fillings, DER values for 6 MV X-ray were 1.065 ± 0.021, 1.100 ± 0.014, and 1.162 ± 0.016 for resin composite filling, low-copper amalgam filling, and high-copper amalgam filling, respectively. Our results revealed that DER regarding irradiation energy was minimum for 6 MV X-rays. With respect to dental restorative filling material, DER was minimum for resin composite filling. Regarding the cavity type, our results with standard deviation (SD) calculations revealed that DER was slightly but not significantly different for both Co-60 gamma ray (1.25 MeV) and 6 MV X-ray energies for both occlusal and MOD cavities. Our dosimetric results for a single beam geometry suggest that, among the three types of filling, resin composite filling is an ideal restorative filling material with minimal morbidity-inducing radiation dose enhancement that may result in increased osteoradionecrosis and secondary caries risk. There is a need for further dosimetric studies with actual clinical beam arrangements.

Structural Changes in HPRT Gene of V79 Cells After Irradiation With Heavy Ions—Immediate and Delayed Effects

The radiobiological effects of accelerated ions with high charge and high energy (HZE) on mammalian cells and their propagation in time are still not sufficiently explained and attract great deal of attention. This work aims to compare the immediate and delayed effects with emphasis on the latter. As shown by our group, the dependence of mutant fraction on expression time after irradiation may have interesting, non-monotonic, character depending on LET (linear energy transfer) of the used heavy ions. We speculate that this phenomenon may occur due to the induced genomic instability. Another area of our research is the study of the DNA structural changes in these mutants induced at different expression times. Chinese hamster V79 cells were irradiated with accelerated ions 11B, 18O, 20Ne, and gamma radiation. The LET was ranging from 0.23 keV/μm of 60Co gamma rays up to 136 keV/μm of 20Ne ions. DNA of unique HPRT mutants was isolated, concentration measured, HPRT exons amplified, and analyzed at several different time points, up to about 40 days, after exposure. Over 1200 HPRT mutants were analyzed for deletions of exons and sorted into three main categories: partial deletion, PD—with deletion of one to eight exons; total deletions, TD—with all nine exons deleted; and no deletions—no change in the HPRT structure observed. In general, the number of samples with partial deletion was increasing with LET of the used radiation, suggesting that higher energy deposition to the cell nucleus is more likely to cause larger structural changes. In the case of total deletions, increase in their number with LET was observed up to LET ∼115 keV/μm followed by a sharp decrease. The samples were also analyzed for the distribution of deletions, in particular exons at various expression times, the so-called mutational patterns. Hypothesis of the mechanisms behind observed phenomena is given, and possible implications for further research are discussed.

Effect of Total Ionizing Dose Damage on 8-Transistor CMOS Star Sensor Performance

The effects of total ionizing dose (TID) radiation from 60Co gamma-rays on an 8-transistor global shutter exposure complementary metal-oxide semiconductor image sensor (CIS) within a star sensor is presented to analyze the sources of star sensor performance degradation and the decrease of attitude measurement accuracy. The dark current, dark signal non-uniformity, and photon response non-uniformity versus the TID are investigated. The signal-to-noise ratio, star diagonal distance accuracy, and star point centroid positioning accuracy of the star sensor versus the TID are also analyzed. By establishing the correlation between space radiation, CIS noise, and star sensor performance parameters, the transfer mechanism of CIS parameter degradation to star sensor parameter degradation is revealed.

X-BAND EPR STUDIES OF GAMMA IRRADIATED A NEW ISOQUINOLINE SULFONAMIDE: C17H20BrNO3S

A new epoxyisoquinoline sulfonamide as a fused heterocycle compound (I), (4aS,7S,8aR)-8a-bromo-7-methyl-2-tosyl-2,3,4,7,8,8a-hexahydro-1H-4a,7-epoxyisoquinoline was synthesized using green and cascade progress which was then irradiated by 60Co-gamma () ray source with a dose speed of 0.981 kGy/h at the room temperature for 72h. EPR spectra of I compound were measured at different orientations in magnetic field with X-band EPR spectrometer along the temperatures between 150-340 K. Isotropic spectrum was obtained without depending on temperature and radical structure, C ̇H_3 H was observed. Radical was simulated using the Bruker software WinEPR-Simfonia and the experimental isotropic g-value with hyperfine coupling constant of radical was calculated.

PESO Y CARACTERES CUANTITATIVOS DE LA CALIDAD EN FRUTOS DE PLANTAS M1 DE Physalis peruviana L. PROVENIENTES DE SEMILLAS IRRADIADAS CON 60Co

Physalis peruviana L. es originaria de los Andes y su fruto se consume fresco por su contenido de vitaminas y propiedades medicinales. El crecimiento de las plantas de esta especie es heterogéneo, pues tiene mejoramiento genético limitado porque es una especie silvestre. Los mutágenos físicos y químicos aplicados a semillas u órganos para propagación pueden generar variedades nuevas con cambios en morfología, rendimiento, adaptabilidad y resistencia. El objetivo de la presente investigación fue determinar el efecto de la irradiación de la semilla en los caracteres de la calidad del fruto de las plantas M1 de Physalis peruviana L., y se hipotetiza que al menos una dosis de la irradiación en plantas M1 de uchuva modifica favorablemente los caracteres de calidad de frutos. El estudio se realizó en invernadero con cubierta de plástico UVII-720, de agosto de 2015 a febrero de 2016. Los tratamientos fueron 14 dosis de rayos gamma 60Co (0 a 275 Gy) y el diseño experimental fue completamente al azar con seis repeticiones. La radiación redujo de 3 a 32% el peso del fruto con cáliz y de 3 a 29% el peso sin cáliz. La dulzura de los frutos se redujo con dosis mayores a 100 Gy, con excepción de 200 Gy; en contraste, la firmeza aumentó de 1 a 9% con las dosis de 100 y 75 Gy. El tamaño y vida de anaquel del fruto no se afectaron. La irradiación de semillas con rayos gamma 60Co altera negativamente el peso y algunas variables de la calidad del fruto de las plantas mutantes de P. peruviana.

Determination of Optimal Modulation Amplitude for Electron Spin Resonance (ESR) Dating and Dosimetry Studies of Tooth Enamel

Fossil remains, which provide important information about past life and ecology, are especially important in natural history and life evolution. Recently, many interdisciplinary dating studies have been conducted and many different techniques have been used to investigate the data obtained in this field. Electron Spin Resonance (ESR) (or alternatively, Electron Paramagnetic Resonance, EPR) is one of the methods used in absolute dating and dosimetry studies. It is based on determination of the radiation-centered radicals obtained from the radiation dose absorbed by irradiated materials. One of the important problems in dosimetry and dating studies performed with ESR method is the dependence of experimental parameters on the accumulated dose. The accumulated dose value is effective in determining the actual result of the dating and dosimetric samples. This value is influenced from the stability of the ESR centers, experimental stages, sample preparation or measurement processes. In this study, how the modulation amplitude parameter affects ESR signal intensity in ESR dating and dosimetry studies of tooth enamel investigated. The selective archaeological animal tooth enamel sample was used from the archaeological site of Köşk Höyük, in Turkey for experimental studies. This sample was prepared with combined processes of mechanical and chemical treatment of tooth in laboratory. Tooth enamel sample was irradiated by 60Co gamma-ray source in dose of 1000 Gy at Çekmece Nuclear Research and Training Center (ÇNAEM), Turkey. After irradiation, ESR spectra were recorded at different modulation amplitude values at room temperature using X-band ESR Spectrometer. According to the results obtained, the most suitable modulation amplitude values for ESR measurements of tooth enamel sample examined in the study was found between 0.25G and 2G.