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Background: The accident at the Fukushima Daiichi nuclear power plant increased the level of anxiety related to the radioactive contamination of various foods sourced in Japan. Particularly, after the accident, the detection of artificial radionuclides in locally produced foods raised food safety concerns. In this study, the radioactivity concentrations and annual ingestions of 40K and 137Cs in food products commonly and frequently consumed by the general public were investigated, and the annual effective dose of each was evaluated.Materials and Methods: The 2016–2018 data from the Radiation Safety Management Report released by the Korea Nuclear Safety Technology Center was referenced for the evaluation of the amounts of 40K and 137Cs contained in food. Using the food-ingestion survey mentioned above as a reference, we selected 62 foods to include in our radioactivity concentration and dose assessment. We also developed a questionnaire and evaluated the responses from the subjects who answered the questionnaire.Results and Discussion: The radioactivity concentration of 137Cs was found to be close to or below the level of minimum detectable activity. Additionally, the annual ingestion of 62 foods was 294.77 kg/yr, the effective doses from 40K and 137Cs were 136.4 and 0.163 μSv/yr, respectively.Conclusion: Thus, the findings confirmed that the effective dose from 40K and 137Cs in food tends to be lower than the effective dose limit of 1 mSv/yr suggested by the International Commission on Radiological Protection (ICRP) Publication 60. The questionnaire developed in this study is expected to be useful for estimating the annual effective dose status of Korean adults who consume foods containing 40K and 137Cs.

The activity of gamma-ray emitting nuclides is calculated assuming that each gamma-ray is detected individually; thus, the magnitude of the coincidence summing signal must be considered during activity calculations. Here, the correction factor for the coincidence summing effect was calculated, and the detection efficiencies of two HPGe detectors were compared. The CANBERRA Inc. GC4018 high-purity Ge detector provided an estimate for the peak-to-total ratio using a point source to determine the coincidence summing correction factor. The ORTEC Inc. GEM60 high-purity Ge detector uses EFFTRAN in LVis to obtain the parameters of the detector and source model and the gamma-gamma and gamma-X match estimates, in order to determine the coincidence summing correction factor. Nuclide analyses, radioactivity comparisons, and analyses of reference material samples were performed utilizing certified reference materials to accurately determine the detection efficiencies. For both Co-60 and Y-88, the detection efficiency for a point source increased by an average of at least 12–13%, whereas the detection efficiency determined using LVis increased by an average of at least 13–15%. The calculated radioactivity values of the certified reference material and reference material samples were accurate to within 3% and 6% of the measured values, respectively.

In this study, we evaluated the effect of radiation dose on gonads during paediatric kidney nuclear medicine tests. Using Monte Carlo simulations, the distribution and effects of radiation were physically evaluated by displaying the distribution path of the source in the human body over time. In particular, the evaluation of doses in children, who are sensitive to radiation during nuclear medicine tests that use internal exposure among several types of medical exposures, was conducted to obtain data for the management of medical exposures. Our results indicated that under normal kidney function, the dose received by the target kidney was 0.430 mGy/mCi, which is ~6% higher than the dose suggested by the International Commission on Radiation Protection (ICRP). Furthermore, when kidney function was compromised, the dose estimated was 0.726 mGy/mCi, which is ~2% lower than the dose suggested by the ICRP. In the male and female gonads, namely the testicles and ovaries, the doses received were 0.359 mGy/mCi and 0.394 mGy/mCi, respectively, under normal kidney function. Similarly, under abnormal kidney function, the doses ranged from 0.187 to 0.353 mGy/mCi and 0.238 to 0.388 mGy/mCi in the male and female gonads, respectively.

Neutron yields from 9Be(p,xn) reactions with a 2-cm thick beryllium target bombarded by proton beams of 5, 6, 7, 8, 9, and 10 MeV were investigated. Neutron beam characteristics through a pilot design of beam shaping assembly were calculated by using MCNP6, PHITS, and GEANT4. The neutron yield with a 10 MeV beam by MCNP6 was 7.7 times larger than values by the other codes, but close to the experimental data. The neutron spectrum and directionality were different among the codes. These differences could stem from different cross-section libraries and models used in the codes. The epithermal flux at the beam irradiation port by MCNP6 was 1.4 × 109 cm−2 s−1 for a proton current of 8 mA hitting the target. The ratio of thermal and epithermal flux was less than 0.01 and the forward directionality was 0.78. However, we suggest a new criterion regarding a ratio of fast and epithermal flux.

In this study, a method of directly evaluating the dose received by the highly radiation-sensitive mammary gland during mammography was investigated, and a corresponding breast phantom was produced that expresses a mammary gland, as an alternative to the existing mixed-form phantom. After designing this breast phantom by performing Monte Carlo simulations, the glandular dose was evaluated and compared with that of a mixed-form phantom. Then, dose evaluation was conducted for current commercial filament materials that could be used to fabricate the phantom by 3-D printing. The results showed that the dose received by the mammary gland was in the range of 1.089-1.237 mGy, and the average difference from that determined using the mixed-form phantom was approximately 1.2 %. Among the filament materials, polylactic acid showed the dose that was the most similar to that of the mammary gland tissue, differing by approximately 2.4 %. Overall, the research results suggest that it is meaningful to evaluate the glandular dose using the developed phantom instead of a mixed-form phantom. Besides, polylactic acid is the most appropriate material for fabricating the mammary gland tissue using a 3-D printer.

The Monte Carlo particle transport codes, FLUKA, PHITS, MCNPX, and MARS15 were benchmarked by comparison to the measured product yields of proton-induced reactions on 209Bi from 43 to 100 MeV energy range. Two rounds of experiment were carried out to measure product yields of 209Bi(p, xn)207,206,205,204,203Po and 209Bi(p, pxn)207,206,205,204Bi reactions by using 100 MeV and 69 MeV proton beams. The targets were arranged in the stacks consisting of 209Bi activation foils, Al and Au monitor foils, and Pb plates as energy degraders. The predictive capability of the codes has been proven to be satisfactory from 55 to 100 MeV energy range. However, all codes are likely to underestimate the product yields of both investigated reactions over whole energy range and also the discrepancy between codes and measurements become larger at energy lower than 55 MeV.

The adverse effects of radiation are proportional to the total dose and dose rate. We aimed to investigate the effects of radiation dose rate on different organs in mice. The mice were subjected to low dose rate (LDR, ~3.4 mGy/h) and high dose rate (HDR, ~51 Gy/h) radiation. LDR radiation caused severe tissue toxicity, as observed in the histological analysis of testis. It adversely influenced sperm production, including sperm count and motility, and induced greater sperm abnormalities. The expression of markers of early stage spermatogonial stem cells, such as Plzf, c-Kit, and Oct4, decreased significantly after LDR irradiation, compared to that following exposure of HDR radiation, in qPCR analysis. The compositional ratios of all stages of spermatogonia and meiotic cells, except round spermatid, were considerably reduced by LDR in FACS analysis. Therefore, LDR radiation caused more adverse testicular damage than that by HDR radiation, contrary to the response observed in other organs. Therefore, the dose rate of radiation may have differential effects, depending on the organ; it is necessary to evaluate the effect of radiation in terms of radiation dose, dose rate, organ type, and other conditions.

The flux-weighted average cross-sections of $${}^{\mathrm {nat}}{\mathrm {Dy}}(\upgamma , {\mathrm {xn}}){}^{{159,157,155}}{\mathrm {Dy}}$$ reactions were measured at the bremsstrahlung end-point energies of 12, 14, 16, 65 and 75 MeV with the activation and off-line $$\upgamma $$ -ray spectrometric technique using the 20 MeV Electron Linac for beams with high Brilliance and low Emittance (ELBE) at Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany and the 100 MeV electron linac at the Pohang Accelerator Laboratory, Korea. The $${}^{\mathrm {nat}}{\mathrm {Dy}}(\upgamma , {\mathrm {xn}}){}^{{157,155}}{\mathrm {Dy}}$$ reaction cross-sections as a function of photon energy were also calculated theoretically using TALYS 1.9 code. Then the flux-weighted average values at different end-point energies were obtained based on the theoretical values of mono-energetic photons. These values were compared with the flux-weighted values of present work and are found to be in general agreement. It was also found that the experimental and theoretical formation cross sections of $${}^{159}{\mathrm {Dy}}$$ , $${}^{157}{\mathrm {Dy}}$$ and $${}^{155}{\mathrm {Dy}}$$ from the $${}^{\mathrm {nat}}{\mathrm {Dy}}(\upgamma , {\mathrm {xn}})$$ reactions increased from their respective threshold values to a certain energy where other reaction channels opened. After reaching a maximum value, the individual reaction cross-sections slowly decreased with the increase of the bremsstrahlung energy due to the initiation of other competing reactions at higher energy, which indicates the impact of the excitation energy. However, the production cross sections of $${}^{157}{\mathrm {Dy}}$$ and $${}^{155}{\mathrm {Dy}}$$ from the $${}^{\mathrm {nat}}{\mathrm {Dy}}(\upgamma , {\mathrm {xn}})$$ reactions slightly increase in between and then decreased slowly with bremsstrahlung energy, which is due to the contributing reactions of higher mass isotopes.

The flux-weighted average cross sections of $$^{\mathrm {nat}}\hbox {In}(\upgamma ,x\hbox {n}$$ ) reactions and isomeric yield ratios of $$^{112\mathrm {m,g}}\hbox {In}$$ , $$^{111\mathrm {m,g}}\hbox {In}$$ , and $$^{110\mathrm {m,g}}\hbox {In}$$ were measured with the bremsstrahlung end-point energies of 50, 60, and 70 MeV using an activation and off-line $$\upgamma $$ -ray spectrometric technique at the Pohang Accelerator Laboratory (PAL), Korea. It was observed that the average cross sections of the $$^{\mathrm {nat}}\hbox {In}(\upgamma ,\hbox {xn})$$ reactions increase with bremsstrahlung energy up to the Gaint Dipole Resonance (GDR) region. Thereafter, it shows a small decrease trend with bremsstrahlung energy due to the opening of another reaction channel. The isomeric yield ratios of same product in the $$(\upgamma ,\hbox {n})$$ , (n,2n), (p,x), ( $$\upalpha ,\hbox {x})$$ , and $$(^{{3}}\hbox {He},\hbox {x})$$ reactions for various targets show that the spin of the target nucleus plays a vital role besides the effect of excitation energy and input angular momentum in determining the isomeric yield ratios.

We measured the thermal neutron capture cross sections (σ0) and resonance integral (I0) of the 187Re(n,γ)188Re reaction relative to that of the 197Au(n,γ)198Au monitor reaction using neutron activation with the Cd ratio method. The investigated samples and monitors were irradiated with and without a 0.5-mm-thick Cd cover for the pulsed neutron source based on the 100-MeV electron linac at the Pohang Accelerator Laboratory (PAL). The induced activities for the reaction products were measured using a high-purity germanium (HPGe) detector. In order to improve the accuracy of the experimental results, the necessary corrections were made. The thermal neutron capture cross sections and resonance integral of the 187Re(n,γ)188Re reaction were determined relative to reference values of σo,Au = 98.65 ± 0.09 barn and Io,Au = 1550 ± 28 barn from the 197Au(n,γ)198Au reaction, respectively. The corresponding values for the 187Re(n,γ)188Re reaction were determined to be σ0,Re = 75.6 ± 3.4 barn and I0,Re = 317 ± 22 barn, respectively. The obtained results are compared with the literature data and discussed.

Neutron capture yields for $$^{{155}}\hbox {Gd}$$, $$^{{156}}\hbox {Gd}$$, $$^{{157}}\hbox {Gd}$$, $$^{{158}}\hbox {Gd}$$, and $$^{{160}}\hbox {Gd}$$ were determined applying the total energy detection principle technique using four $$\hbox {C}_{{6}}\hbox {D}_{{6}}$$ liquid scintillators and a $$^{{10}}\hbox {B}$$-loaded ionization chamber. Time-of-flight experiments were carried out at a 30 m flight path station of the GELINA facility using enriched samples. Parameters for resonances in the energy region between 5 and 500 eV were obtained from a resonance shape analysis with REFIT. Resonance integrals for $$^{{155}}\hbox {Gd}$$ and $$^{{157}}\hbox {Gd}$$ derived from the parameters are 1511 (25) b and 801 (19) b, respectively. Average level spacings, average radiation widths and neutron strength functions were derived. The results were compared with data that are reported in the literature and recommended in evaluated data libraries.

The yield ratios of 85m,gSr were measured in the natSr(γ,xn)85m,gSr reactions with the bremsstrahlung end-point energies of 55-, 60-, and 65-MeV. The experiment was carried out by the activation method in combination with high resolution HPGe γ-ray spectroscopy. In order to improve the accuracy of the experimental results, appropriate experimental procedure was used to reduce the influence of the strong annihilation peak (511 keV) to the 514 keV γ-ray peak of 85gSr. The experimental results are compared to theoretical predictions using code TALYS-1.6. The present results for 55-, and 60-MeV bremsstrahlung end-point energies have been measured for the first time.

The flux-weighted average cross-sections for the 59Co($ \gamma$, xn)58-55Co reactions have been measured with the bremsstrahlung end-point energies of 65 and 75 MeV by using the activation method in combination with the off-line $ \gamma$-ray spectrometry. The measured cross-sections for the $ (\gamma,\mathrm{n})$, $ (\gamma,2\mathrm{n})$, $ (\gamma,3\mathrm{n})$ and $ (\gamma,4\mathrm{n})$ reactions of 59Co at 65 MeV are $ 15.828\pm 0.491$, $ 5.003\pm 0.206$ , $ 0.408\pm 0.047$ and $ 0.039\pm 0.008$ mb, whereas at 75 MeV are $ 15.653\pm 0.361$, 4.965±0.289, $ 0.389\pm 0.062$ and $ 0.036\pm 0.007$ mb, respectively. The 59Co($ \gamma$, xn) reaction cross-sections as a function of photon energy were also theoretically simulated by using TALYS 1.9 code. Then the flux-weighted average cross-sections at different bremsstrahlung energies were obtained from the theoretical values and the literature data at lower energy based on mono-energetic photons. The present data are measured for the first time and are found to be in good agreement with the theoretical flux-weighted average values. It was found that the 59Co($ \gamma$, xn)58-55Co reaction cross-sections increase from their threshold values to a certain bremsstrahlung energy. After a certain energy, the individual 59Co($ \gamma$, xn) reaction cross-sections decrease with the increase of bremsstrahlung energy due to opening of other reaction channels. These two observations indicate the role of excitation energy and its partition in different reaction channels. All the four cobalt isotopes produced from the 59Co($ \gamma$, xn) reactions have medical and other applications.

Approximately 48 medical institutions in South Korea own and use blood irradiators; however, the quality control of blood irradiators is insufficient. This study was conducted to establish quality control procedures for blood irradiators using an alanine dosimeter and to ensure reliability of dosimetry. For dosimetry using alanine dosimeters, measurements were performed using an alanine dosimeter jig developed in this study to ensure dose delivery system reliability. Furthermore, the dose and dose distribution were verified, and the uncertainty was evaluated.

We measured the thermal neutron cross-section (σ0) and resonance integral (I0) of the 152Sm(n,γ)153Sm reaction relative to that of the 197Au(n,γ)198Au reaction. Sm and Au foils with and without a cadmium cover of 0.5 mm were irradiated with moderated pulsed neutrons produced from the electron linac. The induced activities of the reaction products were determined via high energy resolution HPGe detector. The present results: σ0,Sm =212±8 b and I0,Sm =3.02±0.19 kb are consistent with most of the existing reference data.

The isomeric yield ratios of 99m,gRh, 101m,ggRh, and 102m,gRh isomeric pairs produced from the natPd(γ,pxn) reactions were measured with the bremsstrahlung end-point energies of 50-, 55-, 60-, 65-, and 70-MeV at the 100MeV electron linac of the Pohang Accelerator Laboratory, Korea. The measurements were carried out with the activation method in combination with off-line γ-ray spectrometry. In order to improve the accuracy of the activity measurements, the separation of the overlapping γ-rays and the necessary corrections for the counting losses were made. The new experimental results are compared with the theoretical values of the TALYS-1.6 code.

Neutron capture yields of dysprosium isotopes (161Dy, 162Dy, 163Dy, and 164Dy) were measured using the time-of-flight method with a NaI(Tl) spectrometer locate at 27.9m from the spallation neutron target in the ANNRI beamline at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. The resonance parameters were determined using the multilevel R-matrix Bayesian code SAMMY in the neutron energy range of 1 to 300eV. Five resonances of the 161Dy isotope, reported by Shin et al. but not presented in ENDF/B-VII.1, were confirmed in this study. One resonance of the 164Dy isotope presented in ENDF/B-VII.1 was not observed in this study. The measured average level spacings were $2.31\pm 0.23$ eV for 161Dy and $6.91\pm 0.69$ eV for 163Dy. The statistical distributions of the resonance parameters reasonably agreed with the Porter-Tomas distributions and multiple exit channel theory.

We have measured the yield ratio of the high spin state to the low spin state of the isomeric pair 137m,gCe produced in the 141Pr(γ,x)137m,gCe reaction. The experiments were performed by irradiating three praseodymium foils with bremsstrahlung end-point energies of 50-, 60-, and 70-MeV. The induced activities of the 137mCe and 137gCe were measured by means of γ-ray spectroscopy. The γ-ray interference and the contributions of other radioisotopes to the measured activity of both the 137mCe and 137gCe were investigated and corrected. The obtained results are compared with the theoretical predictions using the computer code TALYS 1.8. The present results for the 141Pr(γ,x)137m,gCe reaction were determined for the first time.

Iron phosphate glasses with low melting temperatures of ∼1300 °C were developed to immobilize spent nuclear fuels (SNFs). The glasses have densities of ∼3.15 g/cm3 and glass transition temperatures of ∼540 °C that are high enough to endure the temperatures in geological repositories. The waste loading of CeO2 in the glass was ∼21.92 wt%, which corresponds to ∼30.38 wt% of UO2 at the same molar ratio. Normalized elemental releases from the product consistency test were well below the regulated limit of 2 g/m2. Effective neutron multiplication factor keff was 0.755, which is below nuclear criticality safety regulation (keff = 0.95). Vitrified SNF occupies one-eleventh of the repository space compared to direct disposal of the same amount of UO2, excluding left-over low-level wastes.

After publication of the paper, the authors realized that the acknowledgements were not correct. Their correct version appears in this erratum.

We have measured the isomeric yield ratios of 197m,gPt from the 198Pt(γ,n) reaction and 190m2,g+m1Ir from the natPt(γ,xn1p) reaction, induced with the bremsstrahlung end-point energies of 55-, 60-, and 65-MeV. The measurements were carried out by the activation method in combination with the direct γ-spectrometry. The experiments were performed at the 100 MeV electron linac of the Pohang Accelerator Laboratory (PAL). The obtained results at 55-, 60- and 65-MeV for the 197m,gPt from the 198Pt(γ,n) reaction are 0.166 ± 0.012, 0.174 ± 0.011, and 0.175 ± 0.011, whereas for the 190m2,g+m1Ir from the natPt(γ,xn1p) reaction are 0.072 ± 0.006, 0.084 ± 0.006 and 0.087 ± 0.006, respectively. The present results are measured for the first time over the investigated energy range. The present data are compared with the similar literature data at lower energy to examine the role of excitation energy.

The isomeric yield ratios of 86m,gY, 87m,gY, and 89m,gZr produced in the reactions of 89Y and natZr with end-point bremsstrahlung energies of 45 and 55 MeV have been determined by activation and off-line γ-ray spectrometric technique using the 100 MeV electron linac at Pohang Accelerator Laboratory (PAL), Korea. The present data along with literature data show that the isomeric yield ratios of 86m,gY and 87m,gY in the 89Y(γ,xn) and natZr(γ,x) reactions and those of 89m,gZr in the natZr(γ,x) reaction increase with the end-point bremsstrahlung energy, which indicates the effect of excitation energy. However, the increase trend of the isomeric yield ratios of 87m,gY in the 89Y(γ,xn) reaction and 89m,gZr in the natZr(γ,x) reaction are very fast from the threshold value to 30 MeV due to the giant dipole resonance effect. After certain point of excitation energy, the isomeric yield ratios increase slowly with the end-point bremsstrahlung energy due to the partition of energy in different reaction channels. It was also observed that in both the reactions, the isomeric yield ratios of 87m,gY are always higher than those of 86m,gY. This is because of more number of particle emission and thus the disposition of more excitation energy needed for the formation of 86m,gY compared to 87m,gY.

We have determined the isomeric yield ratios for the isomeric pairs 106m,gAg and 104m,gAg produced on natural silver target nuclei in the bremstrahlung energy region from 40- to 60-MeV. The measurements were carried out by the activation method in combination with direct γ-spectrometry. The necessary corrections were made to improve the accuracy of the experimental results. The present yield ratios measured at 40, 45, 50, 55, and 60 MeV for the 106m,gAg isomeric pair are 0.019 ± 0.002, 0.022 ± 0.002, 0.023 ± 0.002, 0.025 ± 0.002, and 0.025 ± 0.002, and those for the 104m,gAg isomeric pair are 1.26 ± 0.12, 1.34 ± 0.12, 1.36 ± 0.12, 1.43 ± 0.12, and 1.49 ± 0.12, respectively. The obtained results are compared with those existing in literature and discussed.

Neutron capture yields of dysprosium isotopes ( 161Dy, 162Dy, 163Dy, and 164Dy were measured using the time-of-flight method with a 16 segment sodium iodide multiplicity detector. The measurements were made at the 25m flight station at the Gaerttner LINAC Center at Rensselaer Polytechnic Institute. Resonance parameters were obtained using the multilevel R-matrix Bayesian code SAMMY. The neutron capture data for four enriched dysprosium isotopes and one natural dysprosium sample were sequentially fitted. New resonances not listed in ENDF/B-VII.1 were observed. There were 29 and 17 new resonances from 161Dy and 163Dy isotopes, respectively. Six resonances from 161Dy isotope, two resonances from 163Dy, and four resonances from 164Dy were not observed. The capture resonance integrals of each isotope were calculated with the resulting resonance parameters and those of ENDF/B-VII.1 in the energy region from 0.5eV to 20MeV and were compared to the capture resonance integrals with the resonance parameters from ENDF/B-VII.1. A resonance integral value of the natural dysprosium calculated with present resonance parameters was $ 1405 \pm 3.5$ barn. The value is $ \sim 0.3\%$ higher than that obtained with the ENDF/B-VII.1 parameters. The distributions of the present and ENDF/B-VII.1 neutron widths were compared to a Porter-Thomas distribution. Neutron strength functions for 161Dy and 163Dy were calculated with the present resonance parameters and both values were in between the values of “Atlas of Neutron Resonances” and ENDF/B-VII.1. The present radiation width distributions of 161Dy and 163Dy were fitted with the $ \chi^{2}$ distribution by varying the degrees of freedom.

The isomeric yield ratios of

The isomeric yield ratios for the natAg(γ,xn)104m,g,106m,gAg reactions with the end-point bremsstrahlung energies of 45- and 55-MeV have been determined by the off-line γ-ray spectrometric technique using 100 MeV electron linac at Pohang accelerator laboratory, Korea. The present data were compared with literature data in comparable compound nucleus from the natAg(γ,xn), natPd(p,xn), and 103Rh(α,xn) reactions to examine the effects of an excitation energy and an input angular momentum. It is observed that the isomeric yield ratios of 104,106Ag in natAg(γ,xn), natPd(p,xn) and 103Rh(α,xn) reactions increase with the end-point bremsstrahlung energy, proton and alpha energy, which indicate the role of excitation energy. It is also found that for the similar compound nucleus at same excitation energy, the isomeric yield ratio of 104m,gAg is higher in the natPd(p,xn) and 103Rh(α,xn) reactions than those in natAg(γ,xn) reaction, which indicate the effect of an input angular momentum.

The independent isomeric yield ratios of 89g,mZr from the natZr(\( \gamma\),xn) reactions and those of 91g, mMo and 97g,mNb from the natMo(\( \gamma\),x) reactions with the bremsstrahlung end-point energy of 45-70 MeV were determined by an off-line \(\gamma\)-ray spectrometric technique using the 100 MeV electron linac at the Pohang Accelerator Laboratory, Korea. The isomeric yield ratios of 89g,mZr and 97g,mNb from the natZr(\( \gamma\), xn) and natMo(\( \gamma\),x) reactions at the bremsstrahlung end-point energy of 16MeV were also determined by the same technique using the 20MeV electron linac at Helmholtz-Zentrum Dresden-Rossendorf, Germany. The measured isomeric yield ratios of 89g,mZr, 91g,mMo, and 97g,mNb were compared with literature data to examine the role of the Giant Dipole Resonance (GDR). The isomeric yield ratios of the 89g,mZr, 91g,mMo, and 97g,mNb from the above reactions were also calculated by using the computer code TALYS 1.6 and compared with the experimental data to examine the validity of the theoretical model for independent isomeric yield ratio calculations.

This study aims to develop a facility that can irradiate subjects with a desired low dose, which can be used to assess the biological effects of low-dose radiation. We develop a single-occupancy mouse-cage and shelf system with adjustable geometric parameters, such as the distances and angles of the cages relative to the collimator. We assess the irradiation-level accuracy using two measurement methods. First, we calculate the angle and distance of each mouse cage relative to the irradiator. We employ a Monte Carlo n-particle simulation for all of the cages at a given distance from the radiation source to calculate the air kerma and the relative absorbed dose in the in-house designed shelving system; these are found to be approximately 0.108 and 0.109 Gy, respectively. Second, we measure the relative absorbed dose using glass dosimeters inserted directly into the heads and bodies of the mice. For a conventional irradiation system, the irradiation measurements show a maximum discrepancy of 42% between the absorbed and desired doses, whereas a discrepancy of only 6% from the desired dose is found for the designed mouse apartment system. In addition, multi-mouse cages are shown to yield to significantly greater differences in the mouse head and body relative absorbed doses, compared to the discrepancies found for single-occupancy cages in the conventional irradiation system. Our findings suggest that the in-house shelving system has greater reliability for the biological analysis of the effects of low-dose radiation.