Gui Nyun Kim

Production cross-sections of the 89Y(p,x)86,88,89gZr, 86m+g,87g,87m,88gY, 85gSr, and 84gRb nuclear processes were investigated up to 42-MeV proton energy by using a stacked-foil activation technique at the MC-50 cyclotron of the Korea Institute of Radiological and Medical Sciences. Cumulative cross-sections of the 88gY radionuclide have been reported here for the first time from proton activation on natural yttrium target. The present data were compared with the available experimental data as well as theoretical calculations based on the TALYS and the ALICE-IPPE codes, and found in general good agreement among them. Due to the mono-isotopic characteristics of the natural yttrium, the investigated 89Y(p,x)86,88,89gZr, 86m+g,87g,87m,88gY, 85gSr, and 84gRb processes are suitable for testing of nuclear reaction theories and/or mechanism. A quantitative analysis has also done to understand more accurately the predictive power of the model codes by performing calculations of deviation factors between the measured data and respective model calculations. The thick target integral yields, i.e., induced radioactivity per unit fluence of 42-MeV protons were also deduced from the measured cross-sections of the investigated radionuclides. Optimal production pathway for the 89Zr-PET radionuclide using a cyclotron is discussed elaborately. The measured cross-sections of 87gY, 88gY, 88Zr, and 89gZr radionuclides find importance due to their suitable decay characteristics leading to medical and thin layer activation applications. In addition, the present experimental results will play an important role in enrichment of the literature data base for proton-induced reactions on natural yttrium leading to various applications.

Production cross-sections of the residual radionuclides for the natNi(p,x)55,56,57,58 m + gCo, 56,57Ni nuclear reactions were measured up to 40 MeV by using a stacked-foil activation technique at the MC-50 cyclotron of the Korea Institute of Radiological and Medical Sciences. The results were compared with the reported experimental data as well as the theoretical calculations based on the TALYS and the ALICE-IPPE codes. The present results are in general good agreement with the other experimental data and calculated results. The integral yields for thick target were also deduced from the measured excitation functions of the produced radionuclides. The present experimental results will play an important role in enrichment of the literature data base for proton-induced reactions on natural nickel leading to various applications.

Production cross-sections of the 105g+m,106mAg, 100,101Pd, and 100g+m,101m,105g+mRh radionuclides through proton-induced reactions on natural palladium were measured up to 40 MeV by using a stacked-foil activation technique combined with high-resolution γ-ray spectrometry. The production cross-sections of 101Pd and 100g+m,105g+mRh radionuclides have been reported here for the first time from the natPd(p,x) nuclear processes. The present results are compared with the available literature values as well as the theoretical data calculated by the TALYS and the ALICE-IPPE computer codes. A quantitative comparison of the present results with the theoretical data has also been done with several deviation factor definitions. Optimal production pathways of the therapeutic 105gRh radionuclide with minimal contamination using cyclotrons are discussed elaborately.

Photo-neutron cross sections of 197Au were experimentally determined for the bremsstrahlung end-point energies of 50, 60, and 70 MeV, by utilizing activation and off-line γ-ray spectrometric technique, using the 100 MeV electron linac at the Pohang Accelerator Laboratory (PAL), Pohang, Korea. The 197Au(γ, xn; x=1–6) reaction cross sections were calculated as a function of the bombarding photon energy by using the TALYS 1.6 computer code with default parameters. The flux-weighted average cross sections were obtained from the literature data and the theoretical values of TALYS 1.6 and TENDL-2014, for mono-energetic photons, and are found to be in good agreement with the present data. Isomeric yield ratios of 196m2,gAu from the 197Au(γ, n) reaction were also determined for the bremsstrahlung end-point energies of 50, 60, and 70 MeV, from the reaction cross sections of m2- and g-states, based on the present experimental data, and are found to be in good agreement with the theoretical values based on TALYS 1.6 and TENDL-2014.

The excitation functions of various reaction products such as 55,56,57Co, 52Fe, 52,54Mn, and 51Cr in the natFe(p, x) reactions were measured by the stacked-foil activation technique in the energy range between their respective reaction threshold and 45 MeV at the MC-50 cyclotron of the Korean Institute of Radiological and Medical Sciences, Korea. The present experimental data were compared with the existing literature data. It was found that excitation function of 56,57Co and 51Cr from the natFe(p, x) reaction are in agreement with the literature data. However, the cross-sections for natFe(p, x)52Fe reactions are lower and those for natFe(p, x)52Mn and natFe(p, x)54Mn reactions are higher than the literature data. The reaction cross-sections of the above mentioned reaction products were also compared with those from the TENDL-2012 library based on the TALYS-1.4 program as a function of proton energy, which was reproduced the trend of the excitation functions of the experimental natFe(p, x) reaction cross-section. The integral yields for thick target of the investigated radionuclides were calculated from the excitation function.

Excitation functions for the production of the 181,182m,182g,183,184g,186Re and 183,184Ta radionuclides from proton bombardment on natural tungsten were measured using the stacked-foil activation technique for the proton energies up to 40 MeV. A new data set has been given for the formation of the investigated radionuclides. Results are in good agreement with the earlier reported experimental data and theoretical calculations based on the ALICE-IPPE code. The thick target integral yields were also deduced from the measured excitation functions. The deduced yield values were compared with the directly measured thick target yield (TTY), and found acceptable agreement. The investigated radionuclide 186Re has remarkable applications in the field of nuclear medicine, whereas the data of 183,184gRe and 183Ta have potential applications in thin layer activation analysis and biomedical tracer studies, respectively.

The photo-neutron cross-sections of 208Pb and 209Bi induced by 50–70 MeV bremsstrahlung have been measured by using the off-line γ-ray spectrometric technique in the electron linac at the Pohang Accelerator Laboratory. The experimental 208Pb(γ,xn) and the 209Bi(γ,xn) reactions cross-sections at the bremsstrahlung energy region of 50–70 MeV, which are determined for the first time, are in general good agreement with the theoretical values based on the TALYS 1.0 code. We observed that the photo-neutron cross-sections for the (γ,xn) reactions of 209Bi and 208Pb increase with increasing of bremsstrahlung energy from 50 to 70 MeV, which indicates the role of excitation energy. It was also observed that the (γ,xn) reaction cross-sections of the doubly magic shell nuclei 82Pb126 are always higher than those of the singly magic shell nuclei 83Bi126 in the bremsstrahlung energy of 50–70 MeV. This may be due to the fact that either the shell effect are washed out at the higher excitation energy or due to the lower fission cross-section of 208Pb compared to that of 209Bi. This observation indicates that there is a competition reaction between fission and neutron emission.

The excitation functions of 89g,m,90,91m,92mNb,88,89Zr, and 87g,m,88,90m,91mY from alpha-induced reactions on 89Y were measured from their respective threshold to 45 MeV by using a stacked-foil activation technique at the MC-50 cyclotron of the Korean Institute of Radiological and Medical Sciences. The results were compared with the earlier reported data as well as with the theoretical values obtained from the TENDL-2013 library based on the TALYS1.6 code. Our measurements in the energy region from the threshold energy to 45 MeV are in general good agreement with the other experimental data and calculated results. The integral yields for thick target of the produced radionuclides were also deduced from their measured cross sections and the stopping power of 89Y. The measured excitation functions find importance in various practical applications including nuclear medicine and improvement of nuclear model calculations.

Herein, we measured the thermal neutron capture cross section (σ0) and resonance integral (I0) of the 174Yb(n,γ)175Yb reaction relative to those of the reference reaction 197Au(n,γ)198Au. Measurements were conducted based on the activation method using pulsed neutrons combined with the Cd ratio method and offline γ-ray spectrometry. Pulsed neutrons were generated on a 100 MeV electron linac of the Pohang Accelerator Laboratory, Korea. Yb samples and Au monitors were irradiated with and without a 0.5 mm Cd cover to absorb thermal neutrons. The neutron flux was determined via the 115In(n,γ)116mIn reaction. The induced activities of the reaction products were measured using a gamma spectrometer based on a well-calibrated HPGe detector. For the 174Yb(n,γ)175Yb reaction, the thermal neutron capture cross section and resonance integral cross-section were obtained as σ0,Yb = 70.5 ± 4.2 b and I0,Yb = 54.1 ± 4.2 b, relative to the corresponding values of σ0,Au = 98.65 ± 0.09 b and I0,Au = 1550 ± 28 b for the 197Au(n,γ)198Au reference reaction. The obtained results were compared with the measured and evaluated data.

In this study, the isomeric yield ratio (IR) values of 104m,gAg and 106m,gAg in an natAg(γ,xn) reaction at the bremsstrahlung end-point energies (Ee) of 45, 50, 55, 60, 70, and 75 MeV were measured using an off-line gamma-ray spectrometric technique. The IR values at different bremsstrahlung end-point energies were also calculated from the cross-section data available in the TENDL-2019 library, and they were found to exhibit a similar trend with some differences in the magnitude. Herein, the IR values of 104m,gAg and 106m,gAg with the bremsstrahlung end-point energies of 70 and 75 MeV were measured for the first time. The present data were compared with those from the literature for 107,109,natAg(γ,xn), natAg(n,xn), natPd(p,xn), and 103Rh(α,xn) reactions to examine the role of the excitation energy and input angular momentum.

We measured the isomeric yield ratios in the photonuclear reactions of natZr(γ, n)89m,gZr, natZr(γ, xn1p)86m,gY, and 89Y(γ, xn)87m,g,86m,gY by the activation method. The high-purity natural Zr and Y metallic foils in disc shape were irradiated with uncollimated bremsstrahlung beams of 50-, 60-, and 70-MeV generated from an electron linear accelerator at Pohang Accelerator Laboratory. The induced activities in the irradiated foils were measured by the high-resolution γ-ray spectrometric system consisting of a high-purity germanium detector and a multichannel analyzer. The obtained isomeric yield ratios in the formation of 89m,gZr, 87m,gY, and 86m,gY are compared with the corresponding values found in the literature. The measured isomeric yield ratios at the bremsstrahlung energies of 50-, 60-, and 70-MeV are the first measurement except 87Y at 50-MeV bremsstrahlung.

Abstract Production cross-sections of short-lived 103Ag, 104mAg and 104gAg radionuclides from proton-induced reactions on natural palladium (Pd) were measured up to 41 MeV by using a stacked-foil activation technique combined with high resolution γ-ray spectrometry. The present results are compared with the available literature values as well as theoretical data calculated by the TALYS and the ALICE-IPPE computer codes. Note that production cross-sections of the 104mAg radionuclide from natPd(p,xn) processes has been measured here for the first time. Physical thick target yields for the investigated radionuclides were deduced from the respective threshold energy to 41 MeV taking into account that the total energy is absorbed in the targets. Measured data of the short-lived 103Ag radionuclide are noteworthy due to its possible applications as a precursor for the indirect production of widely used therapeutic 103Pd radionuclide via natPd(p,xn)103Ag → 103Pd processes. On the other hand, the investigated 104Ag radionuclide finds importance due to its potential use as a diagnostic and positron emission tomography (PET) imaging analogue. Above all, measured data will enrich the literature database leading to various applications in science and technology.

Abstract We measured production cross-sections of Hf, Lu, and Ta radioisotopes from proton-induced reaction of nat Hf by using a stacked-foil activation and off-line γ-ray spectrometric technique at the MC-50 cyclotron of the Korea Institute of Radiological and Medical Sciences. The results were compared with the reported experimental data as well as the theoretical calculations based on the TALYS 1.4 code. The present results in the energy region from the threshold energy to 45 MeV are in general good agreement with the other experimental data and calculated results. The present experimental results will play an important role in enrichment of the literature data base for proton-induced reactions on natural hafnium leading to various applications. Some of the investigated radionuclides (e.g. 177g Lu) have remarkable applications in the field of nuclear medicine, a thin layer activation analysis, and a trace element analysis.

We measured production cross-sections of Sn, In, and Cd radionuclides from alpha-induced reactions on natCd from their respective threshold to 45 MeV by using a stacked-foil activation technique at the MC-50 cyclotron of the Korea Institute of Radiological and Medical Sciences. The results were compared with the earlier measurements as well as with the theoretical values obtained from the TENDL-2012 library based on the TALYS 1.4 code. Our measurements for the 110,113g,117mSn, 108m,108g,109g,110m,110g,111g,113m,114m,115m,116m,117m,117gIn, and 111m,115gCd radionuclides in the energy region from the threshold energy to 45 MeV are in general good agreement with the other experimental data and calculated results. The integral yields for thick target were also deduced using the measured cross-sections and the stopping power of natural cadmium target and found in agreement with the directly measured yields available in the literature. The measured cross-sections find importance in various practical applications including nuclear medicine and improvement of nuclear model calculations.

We measured the thermal neutron cross-section and the resonance integral of the 98Mo(n,γ)99 Mo reaction by the activation method using a 197Au(n,γ)198 Au monitor reaction as a single comparator. The high-purity natural Mo and Au metallic foils with and without a cadmium shield case of 0.5 mm thickness were irradiated in a neutron field of the Pohang neutron facility. The induced activities in the activated foils were measured with a calibrated p-type high-purity Ge detector. The necessary correction factors for the γ-ray attenuation (Fg), the thermal neutron self-shielding (Gth) and the resonance neutron self-shielding (Gepi) effects, and the epithermal neutron spectrum shape factor (α) were taken into account. In addition, for the 99Mo activity measurements, the correction for true coincidence summing effects was also taken into account. The thermal neutron cross-section for the 98Mo(n,γ)99Mo reaction has been determined to be 0.136 ± 0.007 barn, relative to the reference value of 98.65 ± 0.09 barn for the 197Au(n,γ)198 Au reaction. The present result is, in general, in good agreement with most of the experimental data and the recently evaluated values of ENDF/B-VII.0, JENDL-3.3, and JEF-2.2 by 5.1% (1σ). By assuming the cadmium cut-off energy of 0.55 eV, the resonance integral for the 98Mo(n,γ)99Mo reaction is 7.02 ± 0.62 barn, which is determined relative to the reference values of 1550 ± 28 barn for the 197Au(n,γ)198Au reaction. The present resonance integral value is in general good agreement with the previously reported data by 8.8% (1σ).

The excitation functions of 66,67,68Ga, 62,63,65Zn, 61,64Cu, and 58,60Co radionuclides in the natCu(α, x) reaction were measured in the energy range from 15 to 42 MeV by using a stacked-foil activation method at the MC-50 cyclotron of the Korean Institute of Radiological and Medical Sciences. The measured results were compared with the literature data as well as the theoretical values obtained from the TENDL-2013 and TENDL-2014 libraries based on the TALYS-1.6 code. The integral yields for thick targets of the produced radionuclides were also determined from the measured excitation functions and the stopping power of natural copper.

We measured the cross-sections of the 104g,105,106mAg and 104,107Cd radionuclides produced by proton-induced reactions on natural silver by using a stacked-foil activation technique in the energy range from a threshold energy to 40 MeV at a MC50 cyclotron. The results showed generally good agreement with available data as well as the theoretical data. The integral yields for thick targets were also deduced using the measured cross-sections and the stopping power of natAg over the energy range from a threshold energy to 40 MeV, taking into account that the total energy is absorbed in the targets. The production cross-sections for the 104gAg and the 104Cd radionuclides from natural silver were measured for the first time.

The thermal-neutron cross-sections and the resonance integrals for the 179Hf(n,γ)180mHf and the 180Hf(n,γ)181Hf reactions have been measured by the activation method. The high purity Hf and Au metallic foils within and without a Cd shield case were irradiated in a neutron field of the Pohang neutron facility. The gamma-ray spectra from the activated foils were measured with a calibrated p-type high-purity Ge detector. In the experimental procedure, the thermal neutron cross-sections, σ0, and resonance integrals, I0, for the 179Hf(n,γ)180mHf and the 180Hf(n,γ)181Hf reactions have been determined relative to the reference values of the 197Au(n,γ)198Au reaction, with σ0 = 98.65 ± 0.09 barn and I0 = 1550 ± 28 barn. In order to improve the accuracy of the experimental results, the interfering reactions and necessary correction factors were taken into account in the determinations. The obtained thermal neutron cross-sections and resonance integrals were σ0 = 0.424 ± 0.018 barn and I0 = 6.35 ± 0.45 barn for the 179Hf(n,γ)180mHf reaction, and σ0 = 12.87 ± 0.52 barn and I0 = 32.91 ± 2.38 barn for the 180Hf(n,γ)181Hf reaction. The present results are in good agreement with recent measurements.

We measured the isomeric yield ratios for the 120m,gSb and 122m,gSb isomeric pairs produced by natSb(γ,xn)120m,g,122m,gSb photonuclear reactions in the bremsstrahlung energy region from 40 to 60 MeV with a step size of ΔE = 5 MeV by the activation method. The induced γ-activities of the irradiated samples were measured by a coaxial high purity germanium detector coupled to a PC-based multichannel analyzer. The necessary corrections were made to improve the accuracy of the experimental results. The experimental results at bremsstrahlung energies of 40, 45, 50, 55, and 60 MeV were 0.045 ± 0.003, 0.046 ± 0.003, 0.048 ± 0.003, 0.050 ± 0.003, and 0.049 ± 0.003 for the 120m,gSb isomeric pair, and 0.341 ± 0.022, 0.362 ± 0.020, 0.374 ± 0.021, 0.371 ± 0.021, and 0.358 ± 0.022 for the 122m,gSb isomeric pair, respectively. The present results are the first measurements at bremsstrahlung energies just above the giant dipole resonance region. The obtained results confirm the dependence of the isomeric yield ratios on the incident energy and the reaction channel effect observed in some earlier experiments.

Abstract 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.

Abstract We measured the thermal neutron cross-section and the resonance integral of the reaction 186 W( n , γ) 187 W by the activation method using a 197 Au( n , γ) 198 Au monitor reaction as single comparator. The high-purity natural W and Au metallic foils with and without a cadmium shield case of 0.5 mm thickness were irradiated in a neutron field of the Pohang neutron facility. The induced activities in the samples were measured by high-resolution γ-ray spectrometry with a calibrated p-type high-purity Ge detector. The necessary correction factors for γ-ray attenuation ( F g ), thermal neutron self-shielding ( G th ), and resonance neutron self-shielding ( G epi ) effects, and the epithermal neutron spectrum shape factor ( α ) were taken into account. The thermal neutron cross-section for the 186 W( n , γ) 187 W reaction has been determined to be 37.2 ± 2.1 barn, relative to the reference value of 98.65 ± 0.09 barn for the 197 Au( n , γ) 198 Au reaction. The present result is, in general, in good agreement with most of the experimental data and the recently evaluated value of ENDF/B-VII.0 by 5.7%. By assuming the cadmium cut-off energy of 0.55 eV, the resonance integral obtained is 461 ± 39 barn, which is determined relative to the reference values of 1550 ± 28 barn for the 197 Au( n , γ) 198 Au reaction. The present resonance integral value is in general good agreement with the recently measured values by 9%. The present result is lower than the evaluated ones by 10–13%.

The neutron capture cross sections and the capture γ-ray spectra of 117,119Sn were measured in an energy region from 15 to 100 keV and around 550 keV. A neutron time-of-flight method was adopted with a ns-pulsed neutron source based on the 7Li(p,n)7Be reaction and with a large anti-Compton NaI(Tl) spectrometer. A pulse-height weighting technique was applied to the observed capture γ-ray pulse-height spectra to obtain the capture yields. Using the standard capture cross sections of 197Au, the capture cross sections of 117,119Sn were derived with the errors less than 5%. The capture γ-ray spectra were obtained by unfolding the observed capture γ-ray pulse-height spectra. The present results for the capture cross sections are compared with the previous experimental values and the evaluated values of JENDL-3.3, and ENDF/B-VI.8 and VII.0.

Abstract The isomeric yield ratios of 110m,g In, 111m,g In, 112m,g In, and 117m,g In were measured in photonuclear reactions for the end point energies of bremsstrahlung about 50, 60, and 70 MeV. The isomeric yield ratios were determined from the induced activities in the irradiated samples using a high-purity germanium detector equipped with a multichannel analyzer. The results are the first measurements in this energy region. Experimental values of the isomeric yield ratios are compared with the corresponding values found in the literature.

The production cross sections of residual radionuclides such as 86,88,89gZr, 86g,87m,87g,88Y, 83g,85gSr, and 83,84gRb in the 89Y(p,x) reaction were measured using a stacked-foil activation and offline γ-ray spectrometric technique with proton energies of 57 MeV and 69 MeV at the 100 MeV proton linac in the Korea Multi-purpose Accelerator Complex (KOMAC), Gyeongju, Korea. The induced activities of the activated samples were measured using a high purity germanium (HPGe) detector, and the proton flux was determined using the natCu(p,x)62Zn reaction. The measured data was compared with other experimental data and the data from the TENLD-2015 library based on the TALYS code. The present results are generally lower than those in literature, but are found to be in agreement with the shape of the excitation functions. The integral yields for the thick target using the measured cross sections are given.

The production cross sections of 141,143,144,146,148m,148g,149,150Pm, 139m,147,149Nd, 138m,142gPr, and 139gCe in the natNd(p,x) reactions were determined by a stacked-foil activation technique for the proton energy range up to 45 MeV using the MC-50 cyclotron of Korea Institute of Radiological and Medical Sciences. The measured cross sections were compared with literature data as well as data from the TENDL-2014 library based on TALYS 1.6. The production cross sections of the above radionuclides are slightly higher than the literature data but are in general agreement with values in TENDL-2014 library except for 148mPm, 148gPm, 139mNd, and 142gPr. The thick target integral yields of the produced radionuclides were also deducted from the measured cross sections.

Development of neutron spin filters based on polarized gaseous 3He is underway at KEK. Spin-exchange optical pumping is employed to polarized 3He nuclei. Quartz glass cells and sapphire cells are studied as 3He containers. Spin relaxation times of more than 200 h have been observed for quartz glass cells with 3He pressures of 3 atm. Using a pulsed neutron beam, polarizations of 3He were measured for a quartz glass cell and a sapphire cell with 3He pressures of 3 atm to be 54±2% and 63±1%, respectively.

We measured the isomeric yield ratios for the 44m,gSc isomeric pairs produced from four different photonuclear reactions 45Sc(γ,n)44m,gSc, natTi(γ,xn1p)44m,gSc, natFe(γ,xn5p)44m,gSc, and natCu(γ,xn8p)44m,gSc by using the activation method. The high purity natural Sc, Ti, Fe, and Cu metallic foils in disc shape were irradiated with uncollimated 2.5 GeV bremsstrahlung beams of the Pohang Accelerator Laboratory. The induced activities in the irradiated foils were measured by the high-resolution γ-ray spectrometry with a calibrated high-purity Germanium (HPGe) detector. In order to improve the accuracy of the experimental results the necessary corrections were made in the gamma activity measurements and data analysis. The obtained isomeric yield ratios for the 45Sc(γ,n)44m,gSc, natTi(γ,xn1p)44m,gSc, natFe(γ,xn5p)44m,gSc and natCu(γ,xn8p)44m,gSc reactions are 0.25 ± 0.03, 0.43 ± 0.05, 1.38 ± 0.14, and 1.89 ± 0.21, respectively. The present result for the natCu(γ,xn8p)44m,gSc reaction is in good agreement with the existing data. Our results for the 45Sc(γ,n)44m,gSc, natTi(γ,xn1p)44m,gSc, and natFe(γ,xn5p)44m,gSc reactions are the first measurements at 2.5 GeV bremsstrahlung. The obtained results are compared with the corresponding values found in the literature. The relation between the isomeric yield ratios and the complexity of the photonuclear reactions is discussed.

We measured neutron total cross-sections of natural erbium in the neutron energy region from 0.2 to 120 eV by using the neutron time-of-flight method at the Pohang Neutron Facility, which consists of an electron linear accelerator, a water-cooled tantalum target with a water moderator, and a 12-m-long time-of-flight path. A 6Li–ZnS(Ag) scintillator with a diameter of 12.5 cm and a thickness of 1.6 cm was used as a neutron detector, and a group of high-purity natural erbium metallic plates with various thickness was used for the neutron transmission measurements. The present measurement was compared with the existing experimental and the evaluated data. The resonance parameters of 166Er, 167Er, 168Er, and 170Er in the neutron energy region below 120 eV were extracted from the transmission by using the multilevel R-matrix SAMMY code and were compared with the evaluated data from ENDF/B VII.0 and other previous reported results.

The neutron capture cross-sections and the capture γ-ray spectra of 56Fe and 57Fe have been measured in the neutron energy range from 10 to 90 keV. Pulsed keV-neutrons were produced from the 7Li(p,n)7Be reaction by bombarding a lithium target with a 1.5-ns bunched proton beam from a 3 MV Pelletron accelerator. The incident neutron spectrum on the capture sample was measured using a time-of-flight method with a 6Li-glass detector. The capture γ-rays emitted from an iron or standard gold sample were detected with a large anti-Compton NaI(Tl) spectrometer. The capture yield of the iron or gold sample was obtained by applying a pulse-height weighting technique to the corresponding capture γ-ray pulse-height spectrum. The capture cross-sections of 56,57Fe were derived with errors less than 5% using the standard capture cross-sections of 197Au. The capture γ-ray spectra were obtained by unfolding the observed capture γ-ray pulse-height spectra. The present results for the capture cross-sections were compared with the previous measurements and the evaluated values of ENDF/B-VII.0 and JENDL-3.3. The Maxwellian-averaged capture cross-sections of 56Fe and 57Fe at 30 keV are derived as 12.22 ± 2.06 mb and 44.48 ± 7.56 mb, respectively.

We measured the flux weighted average cross-sections of the natNi(γ,xn)56,57Ni and natNi(γ, pxn)55,56,57,58Co reactions with the bremsstrahlung end-point energies of 55, 59, 61 and 65 MeV by using an activation cum off-line γ-ray spectrometric technique at the Pohang Accelerator Laboratory (PAL), Korea. The natNi(γ, xn) and natNi(γ, pxn) reaction cross-sections as a function of monoenergetic photon were calculated theoretically by using the computer code TALYS-1.8. The flux-weighted average cross-sections of the natNi(γ, xn) and natNi(γ, pxn) reactions from the present work were compared with the similar data from the literature as well as the theoretical values from the TALYS-1.8 code and the TENDL-2015 data library. Both the experimental and theoretical values increase sharply from the reaction threshold to a maximum value where the next reaction channel opens. After the maximum value, individual reaction cross section decreases slowly with increase of bremsstrahlung end-point energy, which may be due to the opening of other possible reaction channels.

The thermal neutron cross section (σ0) and resonance integral (I0) of the 45Sc(n,γ)46Sc reaction have been measured relative to that of the 197Au(n,γ)198Au reaction by means of the activation method. High-purity natural scandium and gold foils without and with a cadmium cover of 0.5 mm thickness were irradiated with moderated pulsed neutrons produced from the Pohang Neutron Facility (PNF). The induced activities in the activated foils were measured with a high purity germanium (HPGe) detector. In order to improve the accuracy of the experimental results the counting losses caused by the thermal (Gth) and resonance (Gepi) neutron self-shielding, the γ-ray attenuation (Fg) and the true γ-ray coincidence summing effects were made. In addition, the effect of non-ideal epithermal spectrum was also taken into account by determining the neutron spectrum shape factor (α). The thermal neutron cross-section and resonance integral of the 45Sc(n,γ)46Sc reaction have been determined relative to the reference values of the 197Au(n,γ)198Au reaction, with σo,Au = 98.65 ± 0.09 barn and Io,Au = 1550 ± 28 barn. The present thermal neutron cross section has been determined to be σo,Sc = 27.5 ± 0.8 barn. According to the definition of cadmium cut-off energy at 0.55 eV, the present resonance integral cross section has been determined to be Io,Sc = 12.4 ± 0.7 barn. The present results are compared with literature values and discussed.

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.

The thermal neutron capture cross section (σ0) and resonance integral cross section (I0) of the 139La(n,γ)140La reaction have been measured relative to that of the 197Au(n,γ)198Au reaction by means of the activation method. High-purity natural lanthanum and gold foils were exposed to pulsed neutrons at the Pohang neutron facility. One set of foils was irradiated directly and a second set of foils was shielded with a cadmium cover of 0.5 mm thickness. The induced activities in the activated foils were measured by a γ-ray spectrometer based on a calibrated high purity germanium (HPGe) detector. In order to improve the accuracy of the experimental results the epithermal neutron spectrum shape factor (α) was determined, and the corrections for the thermal neutron self-shielding (Gth), the resonance neutron self-shielding (Gepi), the γ-ray attenuation (Fg) and the γ-ray coincidence summing effects were made. The thermal neutron cross-section for the 139La(n,γ)140La reaction has been determined to be 9.16 ± 0.36 barn, relative to the reference value of 98.65 ± 0.09 barn for the 197Au(n,γ)198Au reaction. By assuming the cadmium cut-off energy of 0.55 eV, the resonance integral cross section for the 139La(n,γ)140La reaction is 11.64 ± 0.69 barn, which is determined relative to the reference value of 1550 ± 28 barn for the 197Au(n,γ)198Au reaction. The measured results are compared with literature values and discussed.

The isomeric-yield ratios of 109m,gPd and 115m,gCd were measured by the activation method with uncollimated bremsstrahlung beams of 50-, 60-, and 70-MeV generated from an electron linear accelerator at Pohang Accelerator Laboratory. The induced activities in the irradiated foils were measured by the high-resolution γ-ray spectrometric system consisting of a high-purity germanium detector and a multichannel analyzer. The obtained isomeric-yield ratios in the formation of 109m,gPd and 115m,gCd are compared with the corresponding values found in the other experiments and the calculated values based on the statistical model code TALYS. The present results for 109m,gPd and 115m,gCd in this energy region are the first measurement.

The flux-weighted average cross-sections of (γ,xn) reactions on natZn induced by the bremsstrahlung end-point energies of 50, 55, 60, and 65 MeV have been determined by activation and off-line γ-ray spectrometric technique, using the 100 MeV electron linac at the Pohang Accelerator Laboratory (PAL), Pohang, Korea. The theoretical photon-induced reaction cross-sections of natZn as a function of photon energy were taken from TENDL-2014 nuclear data library based on TALYS 1.6 program. The flux-weighted average cross-sections were obtained from the literature data and the theoretical values of TENDL-2014 based on mono-energetic photon. The flux-weighted reaction cross-sections from the present work and literature data at different bremsstrahlung end-point energies are in good agreement with the theoretical values. It was found that the individual natZn(γ,xn) reaction cross-sections increase sharply from reaction threshold to certain values where the next reaction channel opens. There after it remains constant for a while, where the next reaction channel increases. Then it decreases slowly with increase of bremsstrahlung end-point energy due to opening of different reaction channels.

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.

Abstract Excitation functions of the nat Ni(α,x) 60,61 Cu and 64 Ni(α,p) 67 Cu reactions were measured using the stacked-foil activation technique. The experimental data achieved were compared with literature data as well as with nuclear model calculations performed using the code TALYS-1.8. Integral yields from the respective thresholds to 44 MeV were deduced from the measured excitation curves. The >99% pure 61 Cu can be produced using the energy window of E α =20→7 MeV, the yield amounting to 116 MBq/μAh. After a 2 h cooling time, the short-lived 60 Cu (T 1/2 =23 min) impurity will be reduced to <0.1%. Due to low isotopic abundance of 64 Ni, the enriched 64 Ni target would be needed for the production of 67 Cu via the (α,p) reaction. The cost would, however, be very high. In a few cases, particularly above 24 MeV, we have given new data points. In general, our measurements have strengthened the database.

Abstract The neutron total cross-section of natural Dy has been measured in the energy region from 0.025 eV to 100 eV by the neutron time-of-flight method at Pohang Neutron Facility, which consists of an electron linear accelerator, a water-cooled Ta target with a water moderator, and a time-of-flight path with an 11 m length. A 6Li–ZnS(Ag) scintillator with a diameter of 12.5 cm and a thickness of 1.5 cm has been used as a neutron detector and a metallic plate of Dy sample have been used for the neutron transmission measurement. The background level has been determined by using notch-filters of Co, Ta, and Cd sheets. In order to reduce the gamma rays from a Bremsstrahlung and that from a neutron capture, we have employed a neutron-gamma separation system based on their different pulse shape. The present measurements are in general agreement with the previous ones and the evaluated data in ENDF/B-VI. The resonance parameters of Dy isotopes (161,162,163Dy) have been extracted from the transmission data by using the SAMMY code and compared with the previous ones.

The neutron capture cross section of rhodium has been measured in the energy region from 0.003 eV to 80 keV by the neutron time-of-flight method with a 46-MeV electron linear accelerator of the Kyoto University, Research Reactor Institute. An assembly of Bi4Ge3O12 (BGO) scintillators, which was composed of 12 pieces of BGO and placed at a distance 12.7 ± 0.02 m from the neutron source, was employed as a total energy absorption detector for the prompt capture gamma-ray measurement from the sample. In order to determine the neutron flux impinging on the capture sample, a plug of 10B powder sample and the 10B(n, αγ) standard cross section were used.The existing experimental data and evaluated capture cross sections in ENDF/B-VI, JENDL-3.2, and JEF-2.2 have been compared with the current measurement. Popov and Shapiro obtained poor energy resolution data in the resonance region with a lead slowing-down spectrometer. Furthermore, their data are a little higher than the current values above ˜1 keV. The experimental data measured by Weston et al., Hockenbury et al., Macklin and Halperin, Fricke et al., and Block et al. are somewhat higher than the current values. The data measured by Moxon and Rae are somewhat lower than the current values above ˜100 eV. The data measured by Wisshak et al. and Bokhovko et al. are in general agreement with the measurement above 4 keV within the experimental error. The evaluated data in ENDF/B-VI, JENDL-3.2, and JEF-2.2 have been in good agreement with the current result, although the JENDL-3.2 and the JEF-2.2 values are somewhat lower than the measurement in the cross section minimum region from 10 to 100 eV.The thermal neutron cross sections (2200 m/s values) measured by Seren et al. and Walker et al. are in good agreement with the current measurement (133.0 ± 0.93 b) within the experimental error. Other experimental data and the evaluated data are discrepant by 9 to 29% from the measurement.

The thermal neutron cross-section and the resonance integral of the 165Ho(n,γ)166gHo reaction have been measured by the activation method using a 197Au(n,γ)198Au monitor reaction as a single comparator. The high-purity natural Ho and Au foils with and without a cadmium shield case of 0.5 mm thickness were irradiated in a neutron field of the Pohang neutron facility. The induced activities in the activated foils were measured with a calibrated p-type high-purity Ge detector. The correction factors for the γ-ray attenuation (Fg), the thermal neutron self-shielding (Gth), the resonance neutron self-shielding (Gepi) effects, and the epithermal neutron spectrum shape factor (α) were taken into account. The thermal neutron cross-section for the 165Ho(n,γ)166gHo reaction has been determined to be 59.7 ± 2.5 barn, relative to the reference value of 98.65 ± 0.09 barn for the 197Au(n,γ)198Au reaction. By assuming the cadmium cut-off energy of 0.55 eV, the resonance integral for the 165Ho(n,γ)166gHo reaction is 671 ± 47 barn, which is determined relative to the reference value of 1550 ± 28 barn for the 197Au(n,γ)198Au reaction. The present results are, in general, good agreement with most of the previously reported data within uncertainty limits.

An IAEA coordinated research project was launched in December 2012 to establish and improve the nuclear data required to characterise charged-particle monitor reactions and extend data for medical radionuclide production. An international team was assembled to undertake work addressing the requirements for more accurate cross-section data over a wide range of targets and projectiles, undertaken in conjunction with a limited number of measurements and more extensive evaluations of the decay data of specific radionuclides. These studies are nearing completion, and are briefly described below.

A postal dose intercomparison program based on the thermo-luminescence dosimeter (TLD) was carried in order to investigate and reduce uncertainties involved in the measurement of absorbed dose, and to improve the accuracy of dose measurement at different radiotherapy centers in Bangladesh. The intercomparison program was organized by the Secondary Standard Dosimetry Laboratory (SSDL) with the assistance of the IAEA/WHO postal dose intercomparison network. A set of three TLDs (encapsulated LiF powder) including a control was sent to the participating radiotherapy centers for irradiation with 2 Gy of absorbed dose to water. The measurements were made for 60Co and megavolts X-ray beam. Thirteen beams in total were checked. Deviation of ±5% between stated and evaluated dose was considered to be acceptable for 60Co and 6MV X-ray beam. The result of 60Co beam of two centers exceeds the acceptance limit. The maximum deviation was -8.6% with an uncertainty of 1.8% i.e., the ratio of intercomparison dose to locally measured dose was 1.09. We discussed the immediate and corrective action to minimize the discrepancies. For ten 60Co beam measurements, a mean valued of the ratio of intercomparison dose to locally stated dose was 0.988 with a standard deviation of 0.031. The importance of a proper ongoing quality assurance program is essential in maintaining the consistency and the uniformity of absorbed dose measurement for the precision dose delivery to the patient.

Excitation functions of the natPd(p,2pxn)102m,g;101m,g;99m,gRh reactions and the cross section ratios for the isomeric pairs 102m,gRh, 101m,gRh and 99m,gRh have been measured up to 42.61 MeV. The experiments were carried out using a stacked-foil activation technique. The proton beam intensity was determined based on the natCu(p,xn)62Zn and natCu(p,xn)65Zn monitoring reactions. The activities of the irradiated palladium and cooper monitor foils were measured using a HPGe γ-ray detector. The present experimental cross sections are compared with reference data and with the theoretical predictions from TENDL-2015 libraries. The cross sections for the nuclear reactions natPd(p,2pxn)102m,gRh were measured in the energy range of 20–40 MeV and the cross section ratios for all three isomeric pairs 102m,gRh, 101m,gRh and 99m,gRh produced in the natPd(p,2pxn) reactions are the first measurements.

The neutron total cross-sections of Dy and Hf have been measured in the energy region from 0.002 to 100 keV by the neutron time-of-flight method with a 46 MeV electron linear accelerator of the Research Reactor Institute, Kyoto University. A 6Li glass scintillator has been used as a neutron detector and metallic plates of Dy and Hf samples, 0.5–5.0 mm thick, have been used for the neutron transmission measurement. The neutron flight path from the water-cooled Ta target to the 6Li glass scintillator is 22.1±0.01 m. The background level has been determined by the block-off method and/or by using notch-filters of Co (132 eV), Ag (5.2 and 16.3 eV) and Mn (336 eV) and a Cd sheet. The present measurements are in general agreement with the previous ones and the evaluated data in ENDF/B-VI.

The mass-yield distribution of fission products in the 2.5 GeV bremsstrahlung-induced fission of 209Bi have been determined by using the recoil catcher and the off-line γ-spectrometry technique in the high energy electron linac at the Pohang Accelerator Laboratory. The mass-yield determination involves the measurements of cumulative yields for 32 fission products and independent yields of 17 fission products in the photo-fission of 209Bi nuclei. It was found that the mass-yield distribution of fission products in 209Bi is symmetric with an average mass of 95 ± 0.5 and a FWHM of 51 ± 2.0 mass units. Present data at 2.5 GeV along with the literature data at 1 GeV, 700–600 MeV, and 85–28 MeV were interpreted from the point of increase of multi-chance fission and multi-nucleon emission probabilities with an increase in excitation energy. It was found that the average mass of the mass-yield distribution of the fission products decreases from 103 ± 0.5 at 28–85 MeV to 95 ± 0.5 at 2.5 GeV. On the other hand, the FWHM of the mass-yield distribution increases from 19 mass units at 28–40 MeV to 51 mass units at 2.5 GeV. It was also found that the nuclear structure effect observed at the photo-fission of 209Bi with 28–85 MeV bremsstrahlung is washed out at higher energy.

We measured the production cross-sections of 111 In induced by proton on the natCd at several proton energies between 4 MeV and 40 MeV by using a stacked-foil activation technique at the MC50 cyclotron of the Korea Institute of Radiological and Medical Sciences. The present results were compared with the earlier reported experimental data and the theoretical calculations by using both the TALYS code and the ALICE-IPPE code. An overall good agreement was found with the recently reported experimental data and the TALYS prediction, as well. Integral yields of 111In were also deduced from the measured cross-sections.

nat Cu(p,xn) 62 Zn / nat Cu(p,xn) 65 Zn together with a stacked-foil activation technique. The beam energy along with the stacked samples was also theoretically calculated using computer program SRIM-2003. The measured beam energy showed generally a good agreement with the calculated ones, and this fact demonstrated that the energy (<30 MeV) of the proton beam could be determined by irradiating thin metallic Cu foil target with natural isotopic compositions. Hence, this may be considered as a useful technique for beam monitoring purposes in activation experiment.

The isomeric yield ratios (IR) of 86m,gY and 87m,gY were measured in the 23 to 37 MeV quasi-monoenergetic neutron induced reaction of 89Y by using an off-line γ-ray spectrometric technique. The IR values in the 89Y(n,xn) reactions were also calculated using the TALYS 1.8 code and found to be in good agreement for 87m,gY but slightly less for 86m,gY. The IR values of 86m,gY and 87m,gY from the present work in the 89Y(n,xn) reactions were compared with the literature data in the 89Y(γ,xn), 89Y(p,x) and 89Y(α,x) reactions. It was found that the IR values of 86m,gY and 87m,gY in all these reactions increase with excitation energy. At the same excitation energy, the IR values are higher in the alpha induced reaction than in the proton, neutron and photon induced reactions due to higher input angular momentum in the former than in the later. These two observations indicate the role of entrance parameters. However, it is surprising to see that at the same excitation energy, the IR values of 86m,gY and 87m,gY in the 89Y(n,xn) reaction are nearly constant and significantly higher than in the 89Y(γ,xn) reaction.

The production cross sections of 90g,92m,95gNb, 86,88,89g,95Zr, 86g,87m,87g,88Y, 85gSr, and 83Rb in a proton induced nuclear reaction of natural zirconium were measured within the proton energy range of 35.7–66.6 MeV at the Korea Multi-purpose Accelerator Complex (KOMAC), Gyeongju, Korea. The excitation functions of radionuclides produced from the natZr(p,x) reactions were determined through a stacked-foil activation method and an off-line γ-ray spectroscopy. A high purity germanium (HPGe) detector was used to measure the induced activities of the radionuclides. The incident beam energy in each foil was calculated from the SRIM code. The proton flux was determined by using the natCu(p,x)62Zn monitor reaction. The measured data were compared with the experimental data in the literature and the data from the TENDL-2017 library based on the TALYS code. The present results are in general agreement with the literature data and in some cases with the calculated data from the TENDL-2017 library. However, in some of the cases, the calculated data from the TENDL-2017 library overestimate or underestimate the experimental data.

Abstract 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 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.

We activated natDy with a 45-MeV energetic proton beam and studied the production cross-sections of the reaction products 162m,161,159Ho, 159,157,155Dy, and 161,160,156,155Tb. The activation was carried out using an external beam from the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences, Korea. The stacked-foil activation method and off-line γ-ray spectrometry were used to measure the excitation functions of the natDy(p,x) reactions. The thick target yields of the reaction products were also estimated. The excitation functions of the natDy(p,x) reactions were theoretically calculated using TALYS 1.9 code. The measured results were compared with the literature data and the calculated values from the TENDL-2017 library and were found to be in close agreement for most of the reactions.

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.

Abstract The isomeric yield ratios of 133m,gCe and 137m,gCe produced from the natCe(γ,xn) reactions were determined by using the activation and the off-line γ-ray spectrometric technique with the end-point bremsstrahlung energies of 55-, 60-, and 65-MeV at 100-MeV electron linac of the Pohang accelerator laboratory. The induced activities in the irradiated foils were measured by using an energy- and efficiency-calibrated HPGe detector coupled to a PC based multi-channel analyzer. The necessary corrections were made to improve the accuracy of the experimental results. The experimental results at bremsstrahlung energies of 55-, 60-, and 65-MeV were 0.324 ± 0.089, 0.331 ± 0.086, and 0.403 ± 0.089 for the 133m,gCe, and 0.210 ± 0.062, 0.221 ± 0.061, and 0.262 ± 0.061 for the 137m,gCe, respectively. The present results for natCe(γ,xn)133m,g;137m,gCe in this energy region were obtained for the first time which has no comparable literature data. The obtained isomeric yield ratios are compared with the calculated values based on the statistical model code TALYS 1.6.

The isomeric yield ratios in the production of natFe(γ,xnp)52m,gMn have been measured with photonuclear reactions. The high purity natural Fe metallic foils were used and irradiated with bremsstrahlung beams of end point energy 50-, 60-, and 70-MeV. The bremsstrahlung beams are produced with high energy electron beam struck with 0.1mm thin tungsten target. The activation method has been used and hence the induced activities in the irradiated foils were measured by off-line γ-ray spectrometric technique using HPGe detector coupled to a PC-based 4K MCA. The experimental values of isomeric ratios are compared with the theoretical values by statistical model code TALYS. The detail of the formation of isomers by photonuclear reactions together with the literature values of the investigated nuclides are compared and discussed.

Abstract The thermal neutron cross section ( σ 0 ) and the resonance integral ( I 0 ) of the reaction 170 Er(n, γ) 171 Er were measured by an activation method using a reaction 197 Au(n, γ) 198 Au as a single comparator. The high-purity natural erbium ( nat Er) and gold ( 197 Au) foils with and without Cd cover with the thickness of 0.5 mm were irradiated in a neutron field of the Pohang neutron facility. The induced activities in the activated foils were measured with a well calibrated coaxial HPGe detector. The thermal neutron cross section for the 170 Er(n, γ) 171 Er reaction has been determined to be σ 0  = 7.80 ± 0.35 barn, relative to the reference value of 98.65 ± 0.09 barn for the 197 Au(n, γ) 198 Au reaction. By assuming the cadmium cut-off energy of 0.55 eV, the resonance integral for the 170 Er(n, γ) 171 Er reaction is I 0  = 40.4 ± 2.8 barn, which is determined relative to the reference value of 1550 ± 28 barn for the 197 Au(n, γ) 198 Au reaction. In order to improve the accuracy of the experimental results the epithermal neutron spectrum shape factor ( α ) was determined, and the necessary corrections for the counting loss caused by γ-ray attenuation ( F g ), the thermal neutron shelf-shielding ( G th ), the resonance neutron self-shielding ( G epi ) effects, the γ-ray coincidence summing effect, as well as neutron flux fluctuation. The present results are compared with the reference data and discussed.

We measured the integrated cross sections of 110Pd(γ,n)109mPd, 110Pd(γ,n)109gPd and 110Pd(γ,x)108mRh reactions in the energy range from the reaction threshold to 70 MeV bremsstrahlung end-point energy. Measurements were performed by means of the activation method in combination with off-line γ-ray spectrometry. The induced activity of radionuclides was measured with a high-purity germanium (HPGe) detector and necessary corrections for γ-ray interferences were made. The integrated cross section of the studied reactions was measured relative to that of the monitor reaction 27Al((γ,2pn)24Na. Current results are compared with theoretical predictions using the TALYS-1.9 statistical nuclear model code. Calculations were performed using six different level density models in combination with eight γ-strength functions to determine which combinations best fit the experimental results. The present results are measured for the first time.

Abstract In this study, the isomeric yield ratio (IR) values of 196m,g Au and 195m,g Hg in the 197 Au(p,x) reaction within the proton energy range of 49.8–65.5 MeV were measured at the high-intensity proton linac facility (KOMAC) in Korea using an offline γ -ray spectrometric technique. Furthermore, the IR values of the above-mentioned products at different proton energies were calculated from the cross-sections based on the data in the TENDL-2019 library and are found to be higher than the experimental values. The IR values of 196m,g Au and 195m,g Hg in the 197 Au(p,x) reaction from the present and other works are compared with the similar literature data in the 197 Au(γ,n), 196 Hg(γ,n), 197 Au(n,2n), 196 Hg(n,2n), nat Pt(α,x) and nat Pt( 3 He,x) reactions to examine the role of compound nucleus spin, excitation energy, and input angular momentum.

Abstract The cross-sections for the 197 Au(p,pxn) 196-193 Au and 197 Au(p,xn) 197,195,193 Hg reactions within the proton energy range of 49.8–65.5 MeV were measured at the high-intensity proton linac facility (KOMAC) in Korea using the stacked-foil activation and off-line γ-ray spectrometric technique The proton beam intensity was determined based on the nat Cu(p,x) 62 Zn monitor reaction with the recommended cross-section accessed from the IAEA database library. The data gathered in the present work are compared with the available data from the literature, which agreed well with each other. In this study, the 197 Au(p,p5n) 193 Au reaction cross-section was measured for the first time. The data from the present work and existing literature were compared with the TALYS-1.9-based data taken from the TENDL-2019 library, which generally agreed well.

We measured the isomeric yield ratio of the 184m,gRe isomeric pair produced in the natRe(γ,xn)184m,gRe reactions using the activation method combined with residual activity measurements. The experiments were carried out at the bremsstrahlung end-point energies of 50, 60, and 70 MeV. During data analysis, efforts were made to separate overlapping γ-rays, subtract activity contributions from radioactive precursors, and correct for counting losses due to attenuation of γ-rays in the sample. Isomeric yield ratios were also calculated using the statistical nuclear model code TALYS-1.96/2.0, taking into account the effect of the input-level structure of the product nucleus. The present results are the first measurement at bremsstrahlung end-point energies beyond the Giant Dipole Resonance energy range.

Abstract. The flux-weighted average cross section for the 186W(γ,p)185Ta reaction induced with 70 MeV bremsstrahlung end-point energy was measured using the activation method in combination with off-line gamma activity measurement. The 27Al(γ,2pn)24Na monitor reaction was used for the determination of the bremsstrahlung flux. The bremsstrahlung photons used to produce the photonuclear reactions were generated from a thin tungsten (W) converter by bombardment with a 70 MeV electron beam. The experimental flux-weighted average cross section is compared with the theoretical prediction, for which the absolute cross section was calculated using the TALYS 1.95 code and the bremsstrahlung spectrum was simulated using the computer program MCNPX. The present experiment was carried out at the 100 MeV electron linac of the Pohang Accelerator Laboratory, POSTECH, Pohang, Korea.

The production cross sections of 55,56,57Co, 52gFe, 52g,54Mn, 51Cr, and 48V from the natFe(p,x) reactions were measured using a proton energy of 57 MeV at the Korea Multi-purpose Accelerator Complex (KOMAC) in Gyeongju, Korea. The conventional stacked-foil activation method and offline γ-ray spectroscopy were used to determine the excitation functions of proton induced nuclear reactions on iron. The measured excitation functions were compared with experimental data in literature and theoretical data from the TENDL-2021 library. The present data show generally good agreement with other experimental data, but discrepancies were found between the present data and the excitation functions of the TENDL-2021 library in the investigated energy range, except for 56,57Co and 54Mn.

Abstract The flux-weighted average cross sections of the 89 Y(γ, x n; x =1–4) 89− x Y reactions and the isomeric yield ratios of the 87m,g Y, 86m,g Y, and 85m,g Y radionuclides produced in these reactions with the bremsstrahlung end-point energies of 65, 70 and 75 MeV have been determined by an activation and off-line γ-ray spectrometric technique using the 100 MeV electron linac in Pohang Accelerator Laboratory, Korea. The theoretical 89 Y(γ, x n; x =1–4) 89− x Y reactioncross sections for mono-energetic photonshave been calculated using the computer code TALYS 1.6. Then the flux-weighted theoretical values were obtaind to compare with the present data. The flux-weighted experimental and theoretical 89 Y(γ, x n; x =1–4) 89− x Y reaction cross sections increase very fast from the threshold values to a certain bremsstrahlung energy, wherethe other reaction channels open up. Thereafter it remains constant a while and then slowly decreases with the increase of cross sections for other reactions. Similarly, the isomeric yield ratios of 87m,g Y, 86m,g Y and 85m,g Y in the 89 Y(γ, x n; x =2–4) 89− x Y reactions from the present work and literature data show an increasing trend from their respective threshold values to a certain bremsstrahlung energy. After a certain point ofenergy, the isomeric yield ratios increase slowly with the bremsstrahlung energy. These observations indicate the role of excitation energy and its partitioning in different reaction channels.

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 100 MeV 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.

We measured the production cross-sections of 86,87m,87(m+g),88Y radioisotopes for proton-induced reactions on natural zirconium by using a stacked-foil activation technique in the energy range of 4-40 MeV at the MC50 cyclotron of the Korean Institute of Radiological and Medical Sciences. The activation method and the stacked-foil technique using the high-resolution HPGe gamma spectrometry were applied to determine the production cross-sections. The beam current was determined by the monitor reactions natCu(p,x)62Zn and 27Al(p,x)22,24Na. This work reports new data for the above reactions. The results were also compared with ALICE-IPPE model calculations compiled in MENDL-2P file. This experiment is in partial agreement with model calculations. The optimum energy range for the production of 86Y is 40 – 30 MeV The highest yield of 86Y amounts to 33.37 MBq/μAh over this energy range and the levels of the 87Y, 87mY and 88Y impurities to 2.3, 26.55 and 0.33 %, respectively at EOB. The natZr(p,x) process may be a suitable route for the production of the medically important radioisotope 86Y.