Bremsstrahlung Energy Research Articles

Laser-Driven Proton-Boron Fusions: Influences of the Boron State

The proton-boron (p 11 B) reaction is regarded as the holy grail of advanced fusion fuels, where the primary reaction produces 3 energetic α particles. However, due to the high nuclear bounding energy and bremsstrahlung energy losses, energy gain from the p 11 B fusion is hard to achieve in thermal fusion conditions. Owing to advances in intense laser technology, the p11 B fusion has drawn renewed attention by using an intense laser-accelerated proton beam to impact a boron-11 target. As one of the most influential works in this field, Labaune et al. first experimentally found that states of boron (solid or plasma) play an important role in the yield of α particles. This exciting experimental finding rouses an attempt to measure the nuclear fusion cross section in a plasma environment. However, up to now, there is still no quantitative explanation. Based on large-scale, fully kinetic computer simulations, the inner physical mechanism of yield increment is uncovered, and a quantitative explanation is given. Our results indicate the yield increment is attributed to the reduced energy loss of the protons under the synergetic influences of degeneracy effects and collective electromagnetic effects. Our work may serve as a reference for not only analyzing or improving further experiments of the p 11 B fusion but also investigating other beam-plasma systems, such as ion-driven inertial confinement fusions.

Photon beam dose enhancement in AuNP AC tumour through energy moderation of a 6 MeV electron beam: A Monte Carlo study

PurposeTo use Monte Carlo (MC) simulations (BEAMnrc and DOSXYZnrc) to investigate different moderators to slow down 6 MeV electrons before striking a tungsten bremsstrahlung target. The generated x-ray beam is then used to study the dose-effect when the beam traverses a gold-nanoparticle (AuNP) enriched tumour. Materials and methodsIn this study, the 6 MV linear accelerator model was without a beam flattening filter. The BEAMnrc code was used to simulate the 6 MeV electron beam traversing through water or carbon moderators of various thicknesses before striking a thin tungsten target to produce photon beams with effective energies less than the original 6 MV beam (without any moderation). For each beam, a phase-space (PHSP) file was scored to be used in subsequent DOSXYZnrc simulations. The DOSXYZnrc code was utilised to obtain percentage depth dose (PDD) and dose distributions in a 40 × 40 × 40 cm3 water phantom for each beam. All DOSXYZnrc simulations were repeated but with a tumour model near the surface of the water phantom. Dose enhancement effects (DEFs) were calculated in the tumour model as the ratio of the dose in the tumour with and without gold-nanoparticles (AuNPs) seeded into the tumour at a concentration of 7 mg/g. ResultsWater or carbon moderators slowed the primary 6 MeV electron beam down, resulting in lower energy photon beam spectra generated in the tungsten target. Significant dependence of DEFs on the mean energy of the resulting x-ray beams was shown as a function of moderator thickness. For beams moderated to kilovolt energies, the effect was more enhanced as anticipated. DEF values ranged between 1.01 and 1.075 for various moderator/bremsstrahlung x-ray target combinations. The highest DEF (1.075) was obtained for a moderator consisting of either 2.5 cm water or 1.4 cm carbon to slow the 6 MeV electrons down before hitting the tungsten target of 0.07 cm thickness. ConclusionsCarbon and water moderators can effectively slow electrons down before using them to generate low energy bremsstrahlung x-rays to enhance the dose in a tumour seeded with AuNPs. DEF's of up to 1.075 can be obtained whilst using beams of energy lower than 1 MV.

PRODUCT YIELDS FOR THE PHOTOFISSION OF 239Pu WITH BREMSTRAHLUNG AT 17.5 MeV BOUNDARY ENERGY

The values of relative cumulative yields of 12 products (85mKr, 91mY, 92Sr, 97Zr, 99Mo, 105Ru, 133I, 134I, 135I, 138Cs, 139Ba, 142La, 143Ce) of the 239Pu photofission was measured at a maximum bremsstrahlung energy of 17.5 MeV (av-erage excitation energy ~ 12.03 MeV). 239Pu photofission reaction was stimulated on the electron accelerator of the Institute of Electron Physics NAS of Ukraine – M-30 microtron to simulate the spectra of bremsstrahlung’s photons, secondary electrons, and photoneutrons that hit the 239Pu target, the GEANT4 code was used. The input of accom-panying nuclear reactions to the yield of 239Pu photofission products for the given experimental parameters was also evaluating. The obtained experimental data of the yields of products 239Pu photofission were compared with the program codes GEF and Talys1.9.5 simulations.

Charge asymmetry in electron/positron energy loss in nuclear Bremsstrahlung

We calculate the leading Coulomb correction to the Bremsstrahlung energy loss in the electron-nucleus collisions for arbitrary energy of the incoming particle. This correction determines the charge asymmetry, i.e., the difference of electron and positron energy loss. The result is presented in terms of the classical polylogarithms Li2 and Li3. We use modern multiloop methods based on the IBP reduction and on the differential equations for master integrals. We provide both the threshold and the high-energy asymptotics of the found asymmetry and compare them with the available results.

Study of the Dependence of the End-Point Bremsstrahlung Energy on the Residual Gas Pressure during the Pyroelectric Source Operation in Vacuum

Experimental results on the determination of the end-point bremsstrahlung energy during the operation of a pyroelectric source in vacuum at different residual gas pressures are presented. The range of operating residual gas pressures is determined.

Measurements of natCd(γ, x) reaction cross sections and isomer ratio of 115m,gCd with the bremsstrahlung end-point energies of 50 and 60 MeV * *Supported by the National Research Foundation of Korea (NRF) through a grant provided by the Ministry of Science and ICT (NRF-2017R1D1A1B03030484, NRF-2013M7A1A1075764, NRF-2018R1A6A1A06024970)

The flux-weighted average cross sections of natCd(γ, xn)115g,m,111m,109,107,105,104Cd and natCd(γ, x)113g,112,111g,110mAg reactions were measured at the bremsstrahlung end-point energies of 50 and 60 MeV. The activation and off-line γ-ray spectrometric technique was carried out using the 100 MeV electron linear accelerator at the Pohang Accelerator Laboratory, Korea. The natCd(γ, xn) reaction cross sections as a function of photon energy were theoretically calculated using the TALYS-1.95 and the EMPIRE-3.2 Malta codes. Then, the flux-weighted average cross sections were obtained from the theoretical values of mono-energetic photons. These values were compared with the flux-weighted values from the present study and were found to be in general agreement. The measured experimental reaction cross-sections and integral yields were described for cadmium and silver isotopes in the natCd(γ, xn)115g,m,111m,109,107,105,104Cd and natCd(γ, x)113g,112,111g,110mAg reactions. The isomeric yield ratio (IR) of 115g,mCd in the natCd(γ, xn) reaction was determined for the two bremsstrahlung end-point energies. The measured isomeric yield ratios of 115g,mCd in the natCd(γ, xn) reaction were also compared with the theoretical values of the nuclear model codes and previously published literature data of the 116Cd(γ, n) and 116Cd(n, 2n) reactions. It was found that the IR value increases with increasing projectile energy, which demonstrates the characteristic of excitation energy. However, the higher IR value of 115g,mCd in the 116Cd(n, 2n) reaction compared to that in the 116Cd(γ, n) reaction indicates the role of compound nuclear spin alongside excitation energy.

Measurement of average cross sections and isomer ratios for natRe(γ,xn) reactions at the end-point bremsstrahlung energies of 30 MeV and 40 MeV

The cross sections for the natRe(γ,xn) reactions at the bremsstrahlung end-point energies of 30 MeV and 40 MeV have been measured by the activation and the off-line γ-ray spectrometric techniques using a High Purity Germanium (HPGe) detector. The measured natRe(γ,xn) reaction cross sections were compared to the theoretically calculated cross sections using TALYS 1.9 and EMPIRE 3.2 computer codes. The measurements allowed the determination of the Isomeric Cross section Ratios (ICR) for the 182m,gRe and 184m,gRe isomeric pairs. In addition, we have determined a semi-empirical ICR value for the 186m,gRe isomeric pair. These results for the bremsstrahlung end-point energies of 30 MeV and 40 MeV are obtained for the first time.

Control of spectral characteristics of the medical accelerator on the basis of comparison of mass weaking coefficients of different materials

Background. Radiation protection of patients undergoing radiation therapy using linear electron accelerators is based on ensuring the constancy of the equipment parameters set during commissioning. Therefore, studying the possibility of operational assessment of the spectrum characteristics consistency of the generated bremsstrahlung is a priority along with standard dosimetric parameter control procedures. Primarily, this refers to specifying the average measured energy of bremsstrahlung which provides an impartial assessment of the constancy of the whole wave path of the accelerator. However, there is no special diagnostic equipment to determine this parameter. At the same time, the literature data represent a growing interest in the use of CdTe sensors for the analysis of high-energy radiation, including the ones in medical accelerators. Purpose – developing and testing special diagnostic equipment based on semiconductor CdTe sensors, which would implement the assessment of the average measured energy of bremsstrahlung of the medical accelerator 6 MeV via comparing the mass attenuation coefficients in lead and aluminum. Materials and Methods. The paper deals with experimental evaluation of the Varian Clinac 600C linear accelerator (USA) spectrum characteristics carried out at Radiation Oncology Department of State Organization «Grigoriev Institute for Medical Radiology and Oncology of the National Academy of Medical Sciences of Ukraine» via determining the average measured energy of bremsstrahlung. The assessment of the average measured energy of the bremsstrahlung of the accelerator was performed based on comparing two mass attenuation coefficients of radiation with materials having significantly different atomic numbers, i.e. Al and Pb. The assessment of the mass attenuation coefficients was performed on the basis of measuring the average amplitudes of CdTe signals of the sensor, operating in the pulse mode in conjunction with a 16-bit ADC. Pulses of bremsstrahlung from the linear accelerator were recorded by a peak detector for 10 seconds of measurement by the hardware-software complex at 400 monitor units by CdTe sensor with aluminum and lead absorber. The study was performed at a distance of «source-surface» 100 cm with an area of the irradiation field of 20x20 cm. The spectral energy profile of the generated field of bremsstrahlung was studied. Results. The developed equipment was tested by CdTe sensor, which was created taking into account the energy sensitivity of the sensor itself as well as the spectraltemporal characteristics of the pulsed radiation of the accelerator. The approach dealing with assessing the average measured energy of bremsstrahlung of the linear electron accelerator, based on the dependence of the attenuation of radiation by the absorber layer on the radiation energy, has been experimentally confirmed. The theoretical dependence of the average measured energy of bremsstrahlung of the linear accelerator on the ratio of the mass attenuation coefficients of lead and aluminum has been obtained. The energy range from 0.1 to 6 MeV corresponds to the ratio of mass absorption coefficients of lead to aluminum, varying nonlinearly from 33.8 to 1.639. The average measured energy of the linear accelerator of 0.8 MeV corresponds to a mass coefficient ratio of about 1.23 for these materials. The assessed absolute error (from the set value during commissioning the linear accelerator) of the specified measured average energy of bremsstrahlung is up to 12.5% (0.72 MeV), corresponding to the ratio of mass attenuation coefficients – 1.340. Conclusions. The special diagnostic equipment for recording the spectrum characteristics of the Varian Clinac 600C linear accelerator (USA) based on semiconductor CdTe sensors, which along with 16-bit ADC make it possible to estimate the average measured energy of bremsstrahlung via comparing mass attenuation coefficients in Al and Pb has been substantiated and reduced to practice. The assessment of mass attenuation coefficients is carried out based on measuring the average amplitudes of pulses of СdTe sensors operating in a pulse mode.

Mass yield distribution in the 3 GeV bremsstrahlung induced fission of 232Th

The cumulative yields of various fission products within the mass region of 77–153 in the 3-GeV bremsstrahlung induced fission of 232Th have been measured by using the method of recoil catcher and an off-line γ–ray spectrometry at the Pohang accelerator laboratory, Korea. The mass yields were obtained from the cumulative yields of fission products after charge-distribution corrections in the high energy fission. We obtained the mass distribution parameters such as peak-to-valley (P/V) ratio, average light mass (AL), and heavy mass (AH), as well as the average post-fission number of neutrons (vexpt) in the 232Th(γ,f) reactions. We compared the fission yield data in the 232Th(γ,f) and 238U(γ,f) reactions at various bremsstrahlung energies and the following facts were observed. (i) At the bremsstrahlung end-point energy of 2.0–3.5 GeV, the mass yield distribution in the 232Th(γ,f) reaction is triple humps, whereas in the238U(γ,f) reaction, it is double humps. This is due to the different type of potential energy surface between the two fissioning systems. (ii) In both the 232Th(γ,f) and 238U(γ,f) reactions, the yields of asymmetric products decrease marginally, whereas for those of symmetric products increase significantly with bremsstrahlung energy and thus the value of P/V ratio decrease accordingly. (iii) At all the bremsstrahlung energy, the P/V ratio of the 232Th(γ,f) reaction is lower than that of the 238U(γ,f) reaction due to the presence of the third peak in the mass yield distribution of former.

CROSS-SECTIONS OF PHOTONUCLEAR REACTIONS ON natМо TARGETS AT END-POINT BREMSSTRAHLUNG ENERGY UP TO Еγmax = 100 МeV

Experiments to determine the yields and bremsstrahlung flux-averaged cross-sections σ(Еγmax) of photonuclear reactions on the natural Mo targets were performed on the beam from the electron linear accelerator LUE-40 with the use of the γ-activation technique. The bremsstrahlung end-point energies were in the range Еγmax = 35…80 MeV. The bremsstrahlung quantum flux was calculated with the program GEANT4.9.2 and, in addition, was monitored using the 100Мо(γ, n)99Мо reaction. Calculations of the yields and average cross-sections σ(Еγmax) for photonuclear reactions on stable Mo isotopes were computed using the σ(Е) cross-sections from the TALYS1.95 code (for the level density model LD1). A comparison of experimental and calculated cross-sections σ(Еγmax) for reactions 92Мо(γ, 2n)90Мо and 92Мо(γ, pn)90Nb was performed.

Cross-sections for the $${^{27}\!\mathrm{Al}}(\gamma ,x)^{24}\mathrm{Na}$$ multiparticle reaction at $$E_{{\gamma \mathrm{max}}}$$ = 35–95 MeV

The bremsstrahlung flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ and the cross-sections per equivalent photon $\langle{\sigma(E_{\rm{\gamma max}})_{\rm{Q}}}\rangle$ were measured for the photonuclear multiparticle reaction $^{27}\!\rm{Al}(\gamma,\textit{x}; \textit{x} = {^{3}\rm{He}} + pd + 2pn)^{24}\rm{Na}$ at bremsstrahlung end-point energies ranging from 40 MeV to 95 MeV. The experiments were performed using the beam from the NSC KIPT electron linear accelerator LUE-40 with the use of the $\gamma$-activation technique. The bremsstrahlung quantum flux was calculated with the program GEANT4 and, in addition, was monitored by means of the $^{100}\rm{Mo}(\gamma,n)^{99}\rm{Mo}$ reaction. The cross-sections $\sigma(E)$ were computed using the TALYS1.9 code with the default options. The measured average cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ and $\langle{\sigma(E_{\rm{\gamma max}})_{\rm{Q}}}\rangle$ have appeared to be higher by factors of 2.0 to 2.4 than the theoretical results. The experimental results have been found to be in good agreement with the data of other laboratories. Consideration is given to special features of calculation of $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ and $\langle{\sigma(E_{\rm{\gamma max}})_{\rm{Q}}}\rangle$ for the $^{27}\!\rm{Al}(\gamma,\textit{x})^{24}\rm{Na}$ reaction, with occurrence of three $^{27}\!\rm{Al}$ photodisintegration channels. The paper also discusses the possibility of using the $^{27}\!\rm{Al}(\gamma,\textit{x})^{24}\rm{Na}$ reaction for monitoring the bremsstrahlung $\gamma$-quantum flux in the photon energy region above 30 MeV.

Photonuclear production of the medical isotope 67Cu

We studied the production of 67Cu medical radioisotope by irradiating Zn targets of natural isotopic composition by bremsstrahlung photons with endpoint energies of 30 and 40 MeV. Cross-sections per equivalent quantum of 67Cu, 64Cu, 62Zn, 63Zn, 65Zn, and 69mZn activation products were measured. The specific activities of 67Cu were found to be 2.04 and 4.78 µCi/(µA∙h∙g) at the end of the bombardment for 30 and 40 MeV bremsstrahlung maximum energies, respectively.

Assessment of operator exposure from shielded and unshielded sources of 18F and 68Ga – Monte Carlo simulations and empirical measurements

Syringe shields originally designed for 18F are now routinely used with 68Ga. However, 68Ga has a more complex decay scheme than the pure positron emitter 18F. Positrons emitted from the decay of 68Ga possess a maximum energy significantly higher than those of 18F, and are also accompanied by a number of gamma emissions. The higher energy positrons of 68Ga will also result in higher energy Bremsstrahlung radiation from the positrons interacting in radiation shields. The purpose of this study was to determine if personal radiation shielding devices and safe radiation work practices, optimised for 18F are appropriate for 68 Ga.

X-Ray Generation during Piezoelectric Lighter Operation in Vacuum

The results of experimental studies on the generation of x-rays when operating a piezoelectric kitchen lighter in a vacuum are presented. For the first time, a new method for increasing the intensity of x-ray radiation in the piezoelectric effect in a high vacuum through the use of an additional electron emitter is proposed and demonstrated. The maximum energy of x-ray bremsstrahlung reaches 14 keV. This means that electrons are accelerated in vacuum in the field of a piezoelectric ceramic to energy of at least 14 keV.

Structure of Mass-Yield Distributions of 232Th Photofission Product by Bremsstrahlung at Energy 17.5 MeV

Relevance. One of the most promising areas for studying the fission process is to investigate its features under the action of photon radiation, since the interaction of gamma quanta with the nucleus is completely electromagnetic with well-known characteristics. Information on the yields of 232Th nuclear photofission products is of particular interest from the standpoint of experimental and theoretical studies. The nucleus of this element is located on the border between pre-actinides and light actinides. Purpose. The purpose of this study is to experimentally investigate the structure of the mass distribution of yields of 232Th photofission products at a bremsstrahlung energy of 17.5 MeV (energy close to the threshold of the first-chance fission, where experimental data are not available). Methods. 232Th photofission response was simulated on the electron accelerator of the Institute of Electron Physics NAS of Ukraine – M-30 microtron. The bremsstrahlung spectrum was modelled for the case of electron interaction (E=17.5 MeV) with a tantalum converter (1 mm) using the GEANT4 code 10.7. Yields of 232Th photofission products were measured by gamma-ray spectrometry. The yields of 232Th photofission products were modelled using the GEF 2020 / 1.1 and Talys 1.95 codes. Results. The value of cumulative yields of 23 products (85mKr, 88Kr, 88Rb, 89Rb, 91Sr, 92Sr, 94Y, 95Zr, 97Nb, 99Mo, 101Tc, 131I, 132Te, 133I, 134Te, 135I, 138Cs, 139Ba, 140Ba, 141Ce, 142La, 143Ce, 146Ce) belonging to 22 isobaric mass chains (light: 85; 88; 89; 91; 92; 94; 95; 97; 99; 101, heavy: 131; 132; 133; 134; 135; 138; 139; 140; 141 ; 142; 143; 146 fragments) of the 232Th photofission was measured at a maximum bremsstrahlung energy of 17.5 MeV (average excitation energy ~ 11.3 MeV). The resulting mass distribution of heavy fragments indicates the presence of increased yields of products localized around mass 133-134, 138-139, and 143-144, which is associated with the influence of such a nuclear structure as the proximity of closed nuclear shells and the even-odd effect. Conclusions. The measurement results indicate the presence of a fine structure in the resulting mass distribution of 232Th photofission product yields, which is manifested in increased yields of products localised in the mass regions 133-134, 138-139, and 143-144. The obtained theoretical output values calculated using the GEF 2020 / 1.1 and Talys 1.95 codes describe in general terms and predict the fine structure of the mass distribution of 232Th photofission products

Дослідження заселення 7Be в реакціях на ядрах берилію і бору з гальмівними гамма-квантами в широкому діапазоні величин енергії

The average cross-sections were measured at the first time for 7Bе population at bremsstrahlung end-point energies 40 and 55 MeV and for the 10B(γ,t)7Bе reaction at bremsstrahlung end-point energy 20 MeV. The theoretical calculations carried out within the framework of the software packages EMPIRE-3.2 and TALYS-1.9 demonstrate the domination of the nonstatistical processes.

Photo-neutron cross-section of $${}^{{\mathrm {nat}}}{\mathrm {Dy}}$$ in the bremsstrahlung end-point energies of 12, 14, 16, 65, and 75 MeV

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 Study of Photoproduction of Cobalt Radioisotopes from Copper Nuclei

The process of photoproduction of a series of radioisotopes from copper nuclei at the bremsstrahlung end-point energies $$E_{\gamma }^{{\max }}$$ = 21, 30, and 40 MeV was studied at the AANL (YerPhI) linear electron accelerator. The relative yields of 61Co, 60Co, 58Co, 57Co with respect to the 61Cu are measured; in particular, at $$E_{\gamma }^{{\max }}$$ = 40 MeV they are equal to (2.6 ± 0.3) × 10–2, (2.67 ± 0.04) × 10–2, (9.3 ± 0.6) × 10–2, and (0.76 ± 0.04) × 10–2, respectively. It is shown that the predictions of the TALYS model, as well as the model inserted in the GEANT4 software package are in a contradiction (especially in the case of the GEANT4 code) with the measured relative yields. A continuously decreasing energy dependence was observed for the ratio of unfolded (weighted with the bremsstrahlung spectrum) cross-sections of reactions 65Cu(γ,α)61Co and 63Cu (γ,2n)61Cu, similarly to that observed earlier for the ratio of cross-sections of electronuclear reactions 65Cu(e,e′ + α)61Co and 63Cu (e, e′ + 2n)61Cu. The ratio of the 61Co and 64Cu yields is also measured, being equal to (2. 6± 0.2)×10–3, (3.8 ± 0.6) × 10–3, and (3.2 ± 0.4) × 10–3, respectively, at $$E_{\gamma }^{{\max }}$$ = 21 MeV, 30 MeV, and 40 MeV; its value (2.6 ± 0.2) × 10–3 at $$E_{\gamma }^{{\max }}$$ = 21 MeV is consistent with the general trend of the dependence of this ratio on the atomic number Z, measured recently at $$E_{\gamma }^{{\max }}$$ = 23 MeV for heavier nuclei with the atomic numbers from Z = 47 to Z = 82.

Empirical formula for beta-particle-induced bremsstrahlung yields

We have measured the $$\beta $$ -particle-induced bremsstrahlung energy yield and photon yield in the energy range 0.1668–2.274 MeV using beta sources such as $$^{\mathrm {35}}\hbox {S}$$ (0.1668), $$^{\mathrm {99}}\hbox {Tc}$$ (0.293), $$^{\mathrm {147}}\hbox {Pm}$$ (0.225), $$^{\mathrm {90}}\hbox {Sr}$$ (0.5462), $$^{\mathrm {204}}\hbox {Tl}$$ (0.76), $$^{\mathrm {91}}\hbox {Y}$$ (1.5), $$^{\mathrm {32}}\hbox {P}$$ (1.71) and $$^{\mathrm {90}}\hbox {Y}$$ (2.274 MeV) in thick targets of atomic number range $$13<Z<83$$ . We have used a NaI(Tl) detector to measure the bremsstrahlung radiations. Based on the experimental results, we have constructed a semiempirical formula for $$\beta $$ -particle-induced bremsstrahlung energy yield and photon yield. This formula produces bremsstrahlung energy yield and photon yield in the energy range $$0.1668\,\hbox {MeV}< E_{\mathrm {max}}<2.274\hbox { MeV}$$ for thick targets within the atomic number range $$13<Z<83$$ . The values produced by the present formula are compared with the experiments.

Measurement of yield ratios for the isomeric pair 137m,gCe in the 141Pr(γ,x)137m,gCe reactions with bremsstrahlung end-point energies of 50-, 60-, and 70-MeV

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.