Cross-sections for formation of 195mPt through natPt(n,x)195mPt reaction over neutron energy range 13–15 MeV

The cross-sections for formation of metastable state of ¹⁹⁵Pt (^195mPt, 98.85 keV, 4.02 d) through ^natPt(n,x)^195mPt reaction induced by 13.5–14.6 MeV neutrons were measured. Measurements were corrected for gamma-ray attenuations, random coincidence (pile-up), dead time and fluctuation of neutron flux. The data for ^natPt(n,x)^195mPt reaction cross-sections are reported to be 438±46, 399±44 and 372±43 mb at 13.5±0.2, 14.1±0.1 and 14.6±0.2 MeV incident neutron energies, respectively.     

Cross section calculation of (n,p) and (n,2n) nuclear reactions on Zn,Mo and Pb isotopes with ~ 14 MeV neutrons

Journal of Radioanalytical and Nuclear Chemistry - In this article, we are presenting the results of model calculations for (n,p) and (n,2n) reaction cross sections using the standard nuclear...     

14·8 MeV neutron-induced (n, 2n), n,p) and (n, α) cross-sections for some closed shell nuclides

The activation cross-sections for 12 (n,p), (n,α) and (n,2n) reactions have been determined with 14·8 MeV neutrons using enriched sample materials and Ge(Li) γ-ray detection. The closed shell nuclides studied are ⁵⁴Fe, ⁹⁰Zr, ⁹²Mo, ¹⁴¹Pr and ¹⁴⁴Sm. The measured (n,2n) cross-section values are compared with those calculated by theoretical and empirical methods, and to plots of σ(n, 2n) vs the asymmetry parameter. A plot of the (n,2n) experimental data, which accounts for differences in nuclear radii and threshold energies for the same value of asymmetry parameter, is presented.     

Isomeric cross sections for (n, 2n) reactions in thallium,lead, and bismuth at 14·8 MeV

The cross sections for the ²⁰⁵Tl(n, 2n) ^204mTl, ²⁰³Tl(n, 2n) ^202m,gTl, ²⁰⁶Pb(n, 2n) ^205mPb , ²⁰⁷Pb (n, 2n) ^206mPb, ²⁰⁸Pb(n, 2n) ^207mPb and ²⁰⁹Bi(n, 2n) ^208mBi reactions have been measured using the cyclic activation technique and a high-energy resolution Ge(Li) detector. The experimentally determined values of formation cross sections are 664 ± 60, 670 ± 60 and 2482 ± 220, 866 ± 77, 1017 ± 92, 1310 ± 116 and 393 ± 35 mb, respectively. The half-lives of the induced isomeric activities have been determined using a wide range time-to-pulse height converter and a multichannel analyzer.     

Activation cross sections for the 110Pd(n,2n) reaction and the isomeric cross-sections ratio of 109m,gPd in the neutron energy range of 13–15 MeV

Journal of Radioanalytical and Nuclear Chemistry - The 110Pd(n,2n)109m,gPd reaction cross-sections and the isomeric cross section ratios (σm/σg) in the neutron energy range of...     

93Nb(n,2n)92mNb, 93Nb(n,α)90mY and 92Mo(n,p)92mNb reactions at 14.78 MeV and covariance analysis

Journal of Radioanalytical and Nuclear Chemistry - The cross sections for the 93Nb(n,2n)92mNb, 93Nb(n,α)90mY and the 92Mo(n,p)92mNb reactions have been measured with respect to the...     

Measurement of excitation functions of the natAg(α,x) reactions up to 45 MeV

Journal of Radioanalytical and Nuclear Chemistry - We measured excitation functions for the production of the 108m,108g,109g,110m,110g,111gIn, the 109g,111mCd, and the 105g,106m,110m,111gAg in...     

Excitation functions and yield ratios for the isomeric pair 80Br 80mBr formed in (d, 2n), (α, np), (α, p) and (p,n) reactions on selenium

Excitation functions have been measured for the following reactions: ⁸⁰Se(d, 2n) ^80,80mBr, ⁸²Se(d, 2n) 82Br-11·8-6·6 MeV incident deuteron energy - ⁷⁷Se(α, p) ^80,80mBr, ⁷⁸Se(α, np)^80,80mBr, ⁸⁰Se(α, p) ⁸³Br, ⁸²Se(α, 2np) ⁸³Br, ⁸⁰Se(α, np) ⁸²Br - 24·3 - 9·6 MeV incident α energy - and ⁸⁰Se(p, n)^80,80mBr, ⁸²Se(p, n) ⁸²Br - 6-2·5 MeV incident proton energy. The thus obtained cross-sections are compared with Shapiro's and Igo's total cross-section calculations. Yield ratios for the isomeric pair ⁸⁰Br ^80mBr are determined and discussed in terms of the spins of the levels involved, assuming compound nucleus formation.     

Cross-sections for formation of <Superscript>178m2</Superscript>Hf and <Superscript>179m2</Superscript>Hf through reactions on natural hafnium at neutron energy 14.8 ± 0.2 MeV

The cross sections for formation of metastable state of ¹⁷⁸Hf (^178m2Hf, 574.215 keV, 31 y) and ¹⁷⁹Hf (^179m2Hf, 362.55 keV, 25.05 d) through reactions induced by 14.8 ± 0.2 MeV neutrons on natural hafnium were measured for the first time. The monoenergetic neutron beam was produced via the ³H(d, n)⁴He reaction on ZF-300-II Intense Neutron Generator at Lanzhou University. Induced gamma activities were measured by a gamma-ray spectrometer with high-purity germanium (HPGe) detector. Measurements were corrected for gamma-ray attenuations, random coincidence (pile-up), dead time and fluctuation of neutron flux. The neutron fluence were determined by the cross section of ⁹³Nb(n, 2n)^92mNb reaction. The neutron energy in the measurement were by the cross section ratios of ⁹⁰Zr(n, 2n)^89m+gZr and ⁹³Nb(n, 2n)^92mNb reactions.     

Activation cross section data of proton induced nuclear reactions on lanthanum in the 34–65 MeV energy range and application for production of medical radionuclides

Journal of Radioanalytical and Nuclear Chemistry - Activation cross sections of the natLa(p,x)139,137m,137g,135,134,133mCe, natLa(p,x)135,134,133La and 133m,133g,131Ba nuclear reactions have been...     

Potential energy surface and rate constant of the inversion substitution reactions CH3X + O2 → CH3O2• + X• (X = SH,NO2)

The temperature dependence of the rate constant of the inversion substitution reactions CH₃X + O₂ → CH₃O₂^? + X^? (X = SH, NO₂), can be expressed as k = 6.8 × 10^–12(T/1000)^1.49exp(–62816 cal mol^–1/RT) cm³ s^–1 (X = SH) and k = 6.8 × 10^–12(T/1000)^1.26 × × exp(–61319 cal mol^–1/RT) cm³ s^–1 (X = NO₂), as found with the use of high-level quantum chemical methods and the transition state theory.     

Measurement of the 238U(n,γ)239U reaction cross sections in the energy range of 2.0–5.0 MeV by using a neutron activation technique

The neutron capture cross-sections of ²³⁸U at the neutron energies of 4.38?±?0.05 MeV, 3.02?±?0.49 MeV and 2.04?±?0.26 MeV have been measured using the activation method and off-line gamma-ray spectrometric technique. The effects of neutron flux fluctuation, multiple scattering, flux self-shielding and gamma-ray self-absorption were corrected. The excitation function of the ²³⁸U(n,γ)²³⁹U reaction was also calculated using the TALYS-1.9 code. The experimental results were compared with the evaluated data, the theoretical data and the previous experimental data.

     

Independent isomeric-yield ratio of 89m,gNb from 93Nb(γ, 4n), natZr(p,xn), and 89Y(α, 4n) reactions

The independent isomeric-yield ratios of ^89m,gNb for the ⁹³Nb(γ, 4n) ^89m,gNb reaction with bremsstrahlung energies of 45-, 50-, 55-, 60-, and 70-MeV were measured by the activation and the off-line γ-ray spectrometric technique at 100 MeV electron linac of the Pohang accelerator laboratory. The isomeric-yield ratios of ^89m,gNb for the ^natZr(p, xn) ^89m,gNb and the ⁸⁹Y(α, 4n) ^89m,gNb reactions were measured by using a stacked-foil activation technique with the proton energies of 19–45 MeV and alpha energies of 38.9-, 40.5-, and 42.5-MeV at the MC-50 cyclotron of Korea Institute of Radiological and Medical Sciences. The measured isomeric-yield ratio of ^89m,gNb from the ⁹³Nb(γ, 4n), ^natZr(p, xn), and ⁸⁹Y(α, 4n) reactions were compared with the similar literature data in the ⁸⁹Y(³He, 3n) reaction. It was found that the isomeric yield ratio of ^89m,gNb increases with projectile energy, which indicate the effect of excitation energy. However, for the similar compound nucleus with the same excitation energy, the isomeric-yield ratios of ^89m,gNb in the ⁸⁹Y(α, 4n) and ⁸⁹Y(³He, 3n) reactions are higher than those in the ⁹³Nb(γ, 4n) and ^natZr(p, xn) reactions, which indicates the role of input angular momentum. The isomeric-yield ratios of ^89m,gNb in the ⁹³Nb(γ, 4n), ^natZr(p, xn), ⁸⁹Y(α, 4n), and ⁸⁹Y(³He, 3n) reactions were also calculated theoretically using computer code TALYS 1.4. The theoretical isomeric-yield ratios of ^89m,gNb from four reactions increase with excitation energy. However, the theoretical value are significantly higher than the experimental data in the ⁹³Nb(γ, 4n) and ^natZr(p, xn) reactions but slightly lower or comparable in the ⁸⁹Y(α, 4n) rand ⁸⁹Y(³He, 3n) reactions.     

Synthesis,characterization and thermochemistry of Cs(ASP) · nH2O (n = 0, 1)

New compounds of aspartic acid Cs(ASP) · nH₂O (n = 0, 1) have been synthesized and characterized by XRD, IR and Raman spectroscopy as well as TG. The structural formula of this new compound was Cs(ASP) · nH₂O (n = 0, 1). The enthalpy of solution of Cs(ASP) · nH₂O (n = 0, 1) in water were determined. With the incorporation of the standard molar enthalpies of formation of CsOH(aq) and ASP(s), the standard molar enthalpy of formation of −(1202.9 ± 0.2) kJ · mol⁻¹ of Cs(ASP) and −(1490.7 ± 0.2) kJ · mol⁻¹ of Cs(ASP) · H₂O were obtained.     

Saturation molalities and standard molar enthalpies of solution of adenosine(cr), guanosine · 2H2O(cr), inosine(cr), and xanthosine · 2H2O(cr) in H2O(l)

Saturation molalities m(sat) in H₂O(l) have been measured for the substances adenosine(cr), guanosine · 2H₂O(cr), inosine(cr), and xanthosine · 2H₂O(cr) over the temperature range T=287.91 K to T=308.18 K by using h.p.l.c. The indicated states of hydration of these substances were established by performing Karl–Fischer analyses of samples of these substances which had been equilibrated over H₂O(l) and of samples obtained by passing air over the wet crystals (air dried samples). The crystalline phases of these substances were identified by comparison of the results of X-ray diffraction measurements with results from the literature. Molar enthalpies of solution Δ_solH_m for adenosine(cr) and inosine(cr) were measured by using an isoperibol solution calorimeter. A “stacking” or “self-association” model was used to estimate values of the activity coefficients γ and relative apparent molar enthalpies L_φ for these substances. These γ and L_φ values were used to adjust the measured values of m(sat) and Δ_solH_m to the standard state and obtain values of the standard molar Gibbs free energy and enthalpy changes Δ_solG^∘_m and Δ_solH^∘_m, respectively, for the dissolution reactions of these substances. Values of Δ_solH^∘_m calculated from the temperature dependence of values of Δ_solG^∘_m were in good agreement with the values of Δ_solH^∘_m obtained by using calorimetry.     

(α, pxn) reactions on natural samarium

A stack of natural samarium was bombarded with 87 MeV -particles. Cumulative cross sections for the production of¹⁴⁵Eu,¹⁴⁶Eu,¹⁴⁷Eu,¹⁴⁸Eu,¹⁵⁰Eu,¹⁵²Eu and¹⁵⁴Eu have been studied using gamma-ray spectroscopy. The data are compared with the theoretical results provided by equilibrium and pre-equilibrium reaction models, for this purpose we used the code ALICE of Blann.     

First-principles study on the geometries,stabilities and electronic properties of yttrium–silicon clusters (Y2Si n ; 1 ≤ n ≤ 12)

Structural Chemistry - The geometries, growth patterns, relative stabilities and electronic properties of yttrium-doped silicon clusters Y2Si n (n&nbsp;=&nbsp;1–12) are systematically...     

56Fe and 58Fe(n,p) cross sections for 14·4 MeV neutrons

The (n,p) cross sections of ⁵⁶Fe and ⁵⁸Fe for 14·4 MeV neutrons were measured to be 109±10 and 10·±1·0 mbarn, respectively. The ⁵⁸Mn activity had a half-life of 65·3±0·7 sec.     

Investigations of (n,t) cross sections at 14·7 MeV

The (n, t) reaction cross sections have been measured at E_n = 14·7 MeV for 5 isotopes and 7 elements, between A = 9 and 103 using the tritium beta counting technique. The (n, t) reaction cross sections show a general trend to decrease with increasing atomic number. Results are compared with statistical model predictions.