Neutron and light-charged-particle productions in proton-induced reactions on 208Pb at 62.9 MeV

Neutrons and light charged particles produced in 62.9MeV proton-induced reactions on ²⁰⁸Pb were measured during a single experiment performed at the CYCLONE facility in Louvain-la-Neuve (Belgium). Two independent experimental set-ups were used to extract double differential cross-sections for neutrons, protons, deuterons, tritons, ³He and alpha-particles. Charged particles were detected using a set of Si- Si- CsI telescopes from 25^° to 155^°, by step of 10 degrees. Neutrons were measured using shielded DeMoN counters, liquid NE213 scintillators, at 24^°, 35^°, 55^°, 80^° and 120^°. These data allowed the determination of angle differential, energy differential and total production cross-sections. A comparison with theoretical calculations (MCNPX, FLUKA and TALYS) has been performed. It shows that the neutron and proton production rates are well predicted by MCNPX, using the INCL4 option. All the other codes underestimate the neutron production whereas they overestimate the proton one. For composite particles, which represent 17% of the charged particle total reaction cross-section, neither the shape nor the amplitude of the cross-sections are correctly predicted by the models.     

Photonuclear Reactions on Bypassed Nuclei <Superscript>84</Superscript>Sr and <Superscript>92</Superscript>Mo

The yields of photonuclear reactions on mixtures of natural isotopes of strontium and molybdenum that result in the formation and decay of bypassed nuclei ⁸⁴Sr and ⁹²Mo are measured and compared to theoretical results obtained using the TALYS code and calculations in the combined model of photonucleon reaction (CMPR). The need is demonstrated to consider isospin splitting in cases of photoproton reactions. The yields of the ⁹²Mo(γ,p)⁹¹mNb, ⁸⁴Sr(γ,p)⁸³Rb reactions that make the main contribution to the formation and decay of ⁸⁴Sr and ⁹²Mo in the p-process of nucleosynthesis differ from the TALYS and CMPR results by several hundred percent.     

Production parameters of the therapeutic 105 Rh radionuclide using medium energy cyclotron

Production cross-sections of the therapeutic ¹⁰⁵Rh radionuclide from proton-induced reactions on natural palladium target were measured using stacked-foil activation technique combined with high resolution ??-ray spectrometry at the MC50 cyclotron of the Korea Institute of Radiological and Medical Sciences. Note that cyclotron production of the ¹⁰⁵Rh radionuclide from natural palladium target was measured here for the first time. Results are compared with the theoretical values obtained using the model codes TALYS and ALICE-IPPE. Thick target integral yields for the investigated ¹⁰⁵Rh radionuclide were deduced from the threshold energy to 40?MeV. Measured data of the ¹⁰⁵Rh radionuclide are important because of its potential applications in nuclear medicine and/or therapeutic purposes. Optimal production circumstances for the therapeutic ¹⁰⁵Rh radionuclide using a cyclotron are discussed elaborately.     

Photodisintegration of tantalum

The yields of photonucleon reactions on the isotope ¹⁸¹Ta that are induced by bremsstrahlung photons whose endpoint energy is 67.7 MeV are measured by the residual-activity method. The cross sections for photonucleon reactions on the isotope ¹⁸¹Ta are calculated on the basis of the TALYS code and a combined model. The measured reaction yields are compared with their counterparts rescaled from cross sections obtained in experiments that employed beams of quasimonochromatic and bremsstrahlung photons. The spectra of neutrons emitted from ¹⁸¹Ta nuclei after the absorption of photons having various energies are calculated within the TALYS code and the combined model in question.     

Isomers of astrophysical interest in neutron-deficient nuclei at masses A = 81, 85 and 86

Decay properties of neutron-deficient exotic nuclei close to A=80 have been investigated at the IGISOL facility. The studied nuclei, ⁸¹Y, ⁸¹Sr, ^81mKr, ⁸⁵Nb, ⁸⁵Zr, ⁸⁶Mo and ⁸⁶Nb, were produced by a ³²S beam from the Jyv?skyl? isochronous cyclotron on ⁵⁴Fe and ^natNi targets. The internal conversion coefficient for a 190.5 keV isomeric transition in ^81mKr has been measured and the internal transition rate has been determined. The internal transition rate has been used to estimate a neutrino capture rate on ⁸¹Br, which yields a log ft of 5.13±0.09 for the reaction ⁸¹Br( ν, e ^-)^81mKr. A new isomer with a half-life of 3.3±0.9 s has been observed in ⁸⁵Nb. The existence of an earlier reported isomer with a half-life of 56 s in ⁸⁶Nb has not been confirmed.     

Isomeric ratios of the products of (γ, xnp) reactions on 90,91Zr nuclei for a maximum bremsstrahlung energy of 84 MeV

We present the results from measuring and calculatoffing the isomeric ratios for the ^87m,g Y nucleus produced in the ⁹⁰Zr(γ, 2np)^87g,m Y and ⁹¹Zr(γ, 3np)^87g,m Y reactions, and for the ^86m,g Y nucleus produced in the ⁹⁰Zr(γ, 3np)^86g,m Y and ⁹¹Zr(γ, 4np)^86g,m Y reactions. The method of measuring the induced activity of irradiated samples with a semiconductor spectrometer based on an HPGe detector with a relative efficiency of 20% and an energy resolution of 1.9 keV for the 1332 keV ⁶⁰Co line was used to determine the isomeric ratios. The obtained results are compared to calculations using the TALYS code, employing statistical and preequilibrium model approaches.     

Measurement and simulation of the cross sections for nuclide production in 56Fe and natCr targets irradiated with 0.04- to 2.6-GeV protons

The cross sections for nuclide production in thin ⁵⁶Fe and ^natCr targets irradiated by 0.04–2.6-GeV protons are measured by direct γ spectrometry using two γ spectrometers with the resolutions of 1.8 and 1.7 keV for the ⁶⁰Co 1332-keV γ line. As a result, 649 yields of radioactive residual product nuclei have been obtained. The ²⁷Al(p, x)²²Na reaction has been used as a monitor reaction. The experimental data are compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations.     

Measurement and simulation of the cross sections for nuclide production in natW and 181Ta targets irradiated with 0.04- to 2.6-GeV protons

The cross sections for nuclide production in thin ^natWand ¹⁸¹Ta targets irradiated by 0.04–2.6-GeV protons have been measured by direct γ spectrometry using two γ spectrometers with the resolutions of 1.8 and 1.7 keV in the ⁶⁰Co 1332-keV γ line. As a result, 1895 yields of radioactive residual product nuclei have been obtained. The ²⁷Al(p, x)²²Na reaction has been used as a monitor reaction. The experimental data have been compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations.     

Measurement and simulation of the cross sections for nuclide production in 93Nb and natNi targets irradiated with 0.04- to 2.6-GeV protons

The cross sections for nuclide production in thin ⁹³Nb and ^natNi targets irradiated by 0.04- to 2.6-GeV protons have been measured by direct γ spectrometry using two γ spectrometers with the resolutions of 1.8 and 1.7 keV in the ⁶⁰Co 1332-keV γ line. As a result, 1112 yields of radioactive residual nuclei have been obtained. The ²⁷Al(p, x)²²Na reaction has been used as a monitor reaction. The experimental data have been compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations.     

Experimental results on cross sections for 7Be photoproduction on 12C, 14N,and 16O nuclei in the energy range of 40–90 MeV

The yields of A(Γ,X)⁷Be reactions induced by bremsstrahlung photons were measured at the endpoint electron energies of 40, 50, 60, 70, 80, and 90MeV. The spectra of bremsstrahlung incident to the targets used were calculated via a simulation based on the GEANT 4 code passage. The cross sections for the A(γ,X)⁷Be reactions on ¹²C, ¹⁴N, and ¹⁶O nuclei were evaluated on the basis of the measured reaction yields and the calculated bremsstrahlung spectra. The experimental cross sections for the photonuclear reactions of ⁷Be production were comparedwith their counterparts calculated on the basis of the TALYS 1.4 package. Agreement of the experimental and evaluated results was demonstrated for ¹²C nuclei and partly for ¹⁴N nuclei.     

Study of dependence of quasi-particle alignment on proton and neutron numbers in A = 80 region through g-factor measurements

Dependence of quasi-particle alignment on proton and neutron numbers has been studied in A?=?80 mass region through g-factor measurements by using TMF-IMPAD. The experimental results show that for the nuclides ⁸⁴Zr, ⁸⁵Zr and ⁸⁶Zr with Z?=?40 the proton alignment is followed by the neutron alignment in ⁸⁴Zr and ⁸⁵Zr, while the neutron alignment is followed by the proton alignment in ⁸⁶Zr, and for the nuclides ⁸²Sr, ⁸³Y, ⁸⁴Zr and ⁸⁵Nb with N?=?44 the proton aligns only in ⁸²Sr, the proton alignment occurs first that is followed by the neutron alignment in ⁸³Y and ⁸⁴Zr and the neutron alignment is followed by the proton alignment in ⁸⁵Nb. Proton and/or neutron alignments lead to different patterns of the g-factor variation with spin.     

Photonuclear reactions on 112,118,124Sn,natTe, and natHf targets

The yields of products of photonuclear reactions on tin targets enriched in the isotopes ^112,118,124Sn and on Te and HfO₂ targets of natural isotopic composition were measured. The targets were irradiated at the linear electron accelerator of the A.I. Alikhanian National Science Laboratory (Yerevan Physics Institute) at the electron energy of E _e = 40 MeV. The dependence of the product yields on the nucleonic composition of the targets was discussed. The isomeric ratios were obtained for the ^119m,g Te, ^121m,g Te, ^117m,g In, and ^123m,g Sn products. The experimental data in question were compared with their theoretical counterparts calculated on the basis of the TALYS 1.4 code. The dependence of the isomeric ratios on the photon energy and on the mass number of the product is considered.     

Measurement and simulation of the cross sections for the production of 148Gd in thin natW and 181Ta targets irradiated with 0.4- to 2.6-GeV protons

The cross sections for the production of ¹⁴⁸Gd in ^natW and ¹⁸¹Ta targets irradiated by 0.4-, 0.6-, 0.8-, 1.2-, 1.6-, and 2.6-GeV protons at the ITEP accelerator complex have been measured by direct α spectrometry without chemical separation. The experimental data have been compared with the data obtained at other laboratories and with the theoretical simulations of the yields on the basis of the BERTINI, ISABEL, CEM03.02, INCL4.2, INCL4.5, CASCADE07, and PHITS codes.     

Excitation functions of residual nuclei production from 40-2600 MeV proton-irradiated <Superscript>206,207,208,nat</Superscript>Pb and <Superscript>209</Superscript>Bi

The work is aimed at experimental determination of the independent and cumulative yields of radioactive residual nuclei produced in intermediate-energy proton-irradiated thin targets made of highly isotopic enriched and natural lead (^{206,207,208,nat}Pb) and ²⁰⁹Bi. 5972 radioactive product nuclide yields have been measured in 55 thin targets induced by 0.04, 0.07, 0.10, 0.15, 0.25, 0.6, 0.8, 1.2, 1.4, 1.6 and 2.6 GeV protons extracted from the ITEP U-10 proton synchrotron. The measured data have been compared with data obtained at other laboratories as well as with theoretical simulations by seven codes. We found that the predictive power of the tested codes is different but is satisfactory for most of the nuclides in the spallation region, though none of the codes agree well with the data in the whole mass region of product nuclides and all should be improved further.      

Efficiency calibration of Si(Li) and HpGe detectors in the energy range of 5–60 keV

A method is described for the efficiency calibration of Si(Li) and HpGe detectors in the 5–60 keV energy region. The method utilizes theK x-ray lines from⁵⁴Mn,⁶⁵Zn,⁷⁵Se,⁸⁵Sr,⁸⁸Y,¹⁰⁹Cd,¹³⁷Cs,¹⁴¹Ce and¹⁵⁹Dy in addition to⁵⁷Co and²⁴¹Am radioactive sources to have sufficient number of data points. Since the emission intensities are required at variousK x-ray energies from the decay of these sources, this paper reports theK x-ray emission intensities per 100 disintegrations for these nuclei using the latest adopted data for gamma ray intensities, electron capture and internal conversion coefficients, fluorescence yield values and the relative intensities of the fourK x-ray lines.     

The Study of (<Emphasis Type="Italic">n</Emphasis>, 2<Emphasis Type="Italic">n</Emphasis>) Reaction Cross Sections for Ce and Nd Isotopes up to 20 MeV

Neutron cross section calculations for ¹³⁶Ce(n, 2n)¹³⁵Ce, ¹³⁸Ce(n, 2n)¹³⁷Ce, ¹⁴⁰Ce(n, 2n)¹³⁹Ce, ¹⁴²Ce(n, 2n)¹⁴¹Ce, ¹⁴²Nd(n, 2n)¹⁴¹Nd, ¹⁴⁴Nd(n, 2n)¹⁴³Nd, ¹⁴⁶Nd(n, 2n)¹⁴⁵Nd, ¹⁴⁸Nd(n, 2n)¹⁴⁷Nd, and ¹⁵⁰Nd(n, 2n)¹⁴⁹Nd were done in the incident energy range from 10 to 20 MeV. The calculations were performed using three codes TALYS-1.6 for two-component Exciton model, EMPIRE-3.2 Malta for Exciton model, and ALICE/ASH for the Geometry-Dependent Hybrid (GDH) model. The results of model calculations were compared with the available experimental data and also with the evaluated data in the TENDL-2015 (based on the modified TALYS code), ENDF/B-VII.1 libraries. The calculated cross section data were compared with the available experimental data obtained from EXFOR and also compared with semiempirical formulas around 14–15 MeV. The results of model calculation were found to be in good agreement with the experimental data given in literature and semiempirical data around 14–15MeV.     

Thermal neutron induced charged particle reactions in radioactive targets of37Ar,109Cd,125Xe,127Xe,and132Cs

Thermal neutron induced charged particle reactions in a radioactive target of³⁷Ar have been studied. Upper limits of the cross-sections for the (n, α) reaction in radioactive targets of¹⁰⁹Cd,^{125, 127}Xe, and¹³²Cs have been obtained. The isotopically pure targets were produced at the ISOLDE facility at CERN and irradiated with thermal neutrons at the high flux reactor of the Institute Laue-Langevin in Grenoble. Charged particles from (n, p) and (n, α) reactions in³⁷Ar were observed with cross-sections of 69±14b and 1970 ±330b, respectively. TheQ-values for these reactions were determined to be 1600 ±12 keV and 4630±7 keV, in agreement with existing mass data. The branching ratio Γ_α/Γ_p of the³⁷Ar capturing state was found to be 28.5±2.7. An upper limit of the cross-section for the (n, γα) reaction in³⁷Ar was obtained.     

Near-barrier fusion reactions induced by α on197Au,193Ir,191Ir,185Re,181Ta,121Sb and69Ga nuclei

Fusion-evaporation cross-sections for the α-induced reactions upon¹⁹⁷Au,¹⁹³Ir,¹⁹¹Ir,¹⁸⁵Re,¹⁸¹Ta,¹²¹Sb and⁶⁹Ga nuclei at bombarding energies near the Coulomb barrier have been measured by off-line observation of the γ-rays emitted in the radioactive decay of the residual nuclei using stacked foil technique. The total fusion cross-section for the systems have been compared with simple statistical model calculations using the code ALICE/91 as well as with the coupled channel calculations that include the β₂ and ν₄ slatic deformations and dynamic couplings of the vibrational/rotational states of the target and the projet tile using the code CCDEF.     

States in86Sr,84Sr and87Y populated in the (p,t) reaction

The (p,t) reactions on⁸⁸Sr,⁸⁴Sr and⁸⁹Y have been carried out at a bombarding energy of 49.5 MeV. Some low-lying excitations in⁸⁶Sr and⁸⁴Sr associated with configurations of 1g _9/2 and 2p _1/2 neutrons have been identified. Levels populated to 4 MeV of excitation in the strontium nuclei and to 2.5 MeV in⁸⁷Y have been studied in the present experiment. In the case of⁸⁷Y most of the levels populated are of a complex nature.     

Studies on85Sr,86Sr,and101Tc

Results are given on angular correlation for cascadeγ rays from⁸⁵Sr,⁸⁶Sr, and¹⁰¹Tc; the level spins and transition multipole orders have been determined.