Activation cross sections for (n, p) reactions on nickel isotopes induced by neutrons around 14 MeV

The cross sections of ⁵⁸Ni(n, p)^58(m+g)Co,⁶⁰Ni(n, p)^60mCo,⁶¹Ni(n, p)⁶¹Co and ⁶²Ni(n, p)^62mCo reactions induced by neutrons around 14 MeV were measured using activation technique and a coaxial HPGe γ-ray detector. The natural nickel foils of 99.9% purity were used as target materials. Fast neutrons were produced by the T(d, n)⁴He reaction. The neutron flux was determined using the monitor reaction ²⁷Al(n, α)²⁴Na and the neutron energies were measured with the method of cross-section ratios for ⁹⁰Zr(n, 2n)⁸⁹Zr to ⁹³Nb(n, 2n)^92mNb reactions. The results of this work are compared with the collected partial recent data published previously and the estimations obtained from the published empirical formula based on the statistical model with dependence on the Q-value and odd-even effect taken into consideration.     

Cross sections of deuteron induced reactions on Cr up to 50 MeV: Experiments and comparison with theoretical codes

Activation of Cr-containing components around high energy deuteron accelerator can pose radioprotection problems for maintenance personnel. In a stacked foil irradiation, followed by high resolution gamma spectroscopy the cross sections for production of ^46,47,48Sc, ⁵¹Cr, ^52,54Mn and ⁴⁸V were measured up to 50 MeV resulting in first systematic assessment above 15 MeV. Reduced uncertainty is obtained by simultaneous remeasurement of the Al(d,x)²⁴Na or Ti(d,x)⁴⁸V monitor reactions over the whole energy range. A comparison with experimental literature values and results from updated theoretical codes (ALICE-D, EMPIRE-D and the TENDL2010 on-line library) is discussed.     

Calculation and analysis of p + Ca reaction cross sections at incident energies from threshold to 250 MeV

All cross sections, angular distributions and energy spectra of neutron, proton, deuteron, triton, helium, alpha particle emission for p + ^{40,42,43,44,46,48,nat}Ca reactions have been calculated and analyzed at incident proton energies from threshold to 250 MeV by nuclear theoretical models. The theoretical calculated results are in good agreement with existing experimental data.     

Activation cross sections for Os(n,p)Re, Os(n,p)Re and Os(n,n′)Os reactions from 13.5 to 14.8 MeV

Cross sections for (n,p) and (n,n′) reactions have been measured on osmium isotopes at the neutron energies from 13.5 to 14.8 MeV using the activation technique in combination with high-resolution gamma-ray spectroscopy. Neutrons were produced via the ³H(d,n)⁴He reaction using solid TiT. The neutron fluences were determined using the monitor reaction ⁹³Nb(n,2n)^92mNb. Data are reported for the following reactions: ¹⁹⁰Os(n,p)^190mRe, ¹⁹⁰Os(n,p)^190gRe, ¹⁹⁰Os(n,p)¹⁹⁰Re, ¹⁸⁸Os(n,p)¹⁸⁸Re and ¹⁹⁰Os(n,n′)^190mOs. Nuclear model calculations using the code HFTT, which employs the Hauser-Feshbach (statistical model) and exciton model (precompound effects) formalisms, were undertaken to describe the formation of the products. The cross sections were discussed and compared with experimental data found in the literature, with values of model calculations including the pre-equilibrium contribution, and with evaluation data of JEFF-3.1/A.     

Investigation of activation cross-sections of deuteron induced reactions on vanadium up to 40 MeV

Experimental excitation functions for deuteron induced reactions up to 40 MeV on natural vanadium were measured with the activation method using a stacked foil irradiation technique. From high resolution gamma spectrometry cross-section data for the production of ⁵¹Cr, ⁴⁸V, ^48,47,46Sc and ⁴⁷Ca were determined. Comparisons with the earlier published data are presented and results for values predicted by different theoretical codes are included. Thick target yields were calculated from a fit to our experimental excitation curves and compared with the earlier experimental data. Depth distribution curves used for thin layer activation (TLA) are also presented.     

Calculation and analysis of cross-sections for p+Zr reactions up to 200 MeV

Proton-induced reactions on ^{90,91,92,94,96,nat}Zr were studied in the energy range from threshold to 200 MeV. All cross-sections, elastic and inelastic scattering angular distributions were calculated and analyzed by using nuclear theoretical models which integrate optical model, distorted born wave approximation theory, intra-nuclear cascade model, pre-equilibrium and equilibrium reaction theories. Theoretical calculated results are compared with existing experimental data.     

Cross sections for ionization of K, L and M shells of atoms by impact of electrons and positrons with energies up to 1 GeV: Analytical formulas

Analytical formulas are presented for the easy calculation of cross sections for ionization of K, L and M shells of neutral atoms by impact of electrons and positrons with kinetic energies up to 1 GeV. Each formula contains a number of parameters that are characteristic of the element, the active electron shell and the projectile particle. The values of these parameters were determined by fitting the cross section values in an extensive database that was calculated recently by means of a composite algorithm that combines the distorted-wave and plane-wave Born approximations. Tables of parameter values are given for all elements, from hydrogen (Z=1) to einsteinium (Z=99). The proposed analytical expressions yield ionization cross sections that agree with those in the numerical database to within about 1%, except for projectiles with near-threshold energies.     

Excitation functions of (p,x) reactions on natural nickel up to 40 MeV

Production cross-sections of the residual radionuclides for the ^natNi(p,x)^{55,56,57,58 m + g}Co, ^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.     

Alpha induced reactions on Cd up to 38.5 MeV: Experimental and theoretical studies of the excitation functions

The energy dependence of the cross sections of threshold reactions induced by alpha particles on targets of natural cadmium is studied in the energy range from threshold up to 38 MeV. Using a stacked foil irradiation technique and classical gamma-spectroscopy the formation of the radioisotopes ^{110,113m+g,117m}Sn, ^{108m,g,109g,110m,g,111cum,113m,114m,115m,116m,117m,g}In and ^111m,115gCd was assessed. The newly obtained excitation functions were compared with earlier published values, measured either on enriched or natural Cd targets. The results of calculations based on theoretical models of nuclear reactions obtained by the codes ALICE-IPPE, EMPIRE and GNASH are presented. Thick target yields and production routes for some medically relevant radioisotopes are discussed.     

Experimental study of the excitation functions of deuteron induced reactions on Sn up to 40 MeV

Using the stacked-foil activation technique, cross-sections of deuteron induced reactions on natural Sn were measured up to 40 MeV. Excitation functions are reported for the product nuclides ¹¹¹In, ¹¹³Sn, ^117mSn, ^125mSn, ^125gSn, ¹¹⁵Sb, ^116mSb, ¹¹⁷Sb, ^118mSb ^120mSb, ¹²²Sb, ¹²⁴Sb and ¹²⁵Sb and compared with the earlier published data sets. For all excitation functions comparisons with theoretical calculations using the ALICE-IPPE, EMPIRE, EAF and the TALYS codes were performed.     

Calculation and evaluation of cross-sections for p+Fe reactions up to 250 MeV

All cross-sections of proton-induced reactions, angular distributions and the energy spectra of neutron, proton, deuteron, triton, helium and alpha-particle emission are consistent calculated and analyzed for p+^{54,56,57,58,nat}Fe at incident proton energies below 250 MeV by using nuclear theoretical models which integrate the optical model, the intra-nuclear cascade model, direct, preequilibrium and equilibrium reaction theories. Especially, the cross-sections of the light composite particle (d, t, ³He and α) emissions are improved based on the exciton model including the pick-up mechanism. Theoretical calculated results are compared with existing experimental data.     

Experimental study of the Ho(d, 2n) and Ho(d, p) nuclear reactions up to 20 MeV for production of the therapeutic radioisotopes Er and Ho

The radioisotope ¹⁶⁵Er (T_1/2 = 10.36 h) is a candidate for Auger-electron therapy. The β⁻-emitting ^166gHo (T_1/2 = 26.83 h) is now being explored for various therapeutic applications. In the frame of our systematic study of charged particle production routes of therapeutic radionuclides the excitation functions of the ¹⁶⁵Ho(d, 2n)¹⁶⁵Er and ¹⁶⁵Ho(d, p)^166gHo reactions were measured up to 20 MeV by using a stacked foil irradiation technique and X/γ-ray spectroscopy. The excitation function of the ¹⁶⁵Ho(d, 2n)¹⁶⁵Er reaction was measured for the first time while for the ¹⁶⁵Ho(d, p)^166gHo reaction only a single dataset of earlier measured cross-sections was found. The measured excitation functions were compared to the results of different nuclear reaction model codes. The calculated thick target yield of the ¹⁶⁵Ho(d, 2n) reaction is significantly higher over the optimal energy range than that for the ¹⁶⁵Ho(p, n) reaction investigated earlier by us. The integral yield of the ¹⁶⁵Ho(d, p)^166gHo reaction is rather low compared to the established ¹⁶⁵Ho(n, γ)¹⁶⁶Ho reaction in a nuclear reactor.     

Activation cross sections and isomeric cross section ratios for the (n,2n) reactions on Lu, Pt and Se from 13.5 to 14.6 MeV

The cross sections for the ¹⁷⁵Lu(n,2n)^174m,gLu, ¹⁹⁸Pt(n,2n)^197m,gPt and ⁸²Se(n,2n)^81m,gSe reactions and their isomeric cross section ratios σ_m/σ_g have been measured in the neutron energy range of 13.5-14.6 MeV using the activation technique. Nuclear model calculations using the code HFTT, which employs the Hauser-Feshbach (statistical model) and exciton model (precompound effects) formalisms, were undertaken to describe the formation of the products. The total cross sections for the (n,2n) reaction on ¹⁷⁵Lu, ¹⁹⁸Pt and ⁸²Se are compared with experimental data found in the literature, with results of published empirical formulae, and with values of model calculations including the pre-equilibrium contribution.     

Study of the excitation functions for K, Sc and Ti by proton irradiation on Sc up to 37 MeV

The excitation functions of proton induced reactions on Sc targets (100% ⁴⁵Sc), leading to the formation isotopes ⁴³K, ⁴³Sc, ^44mSc, ^44gSc and ⁴⁴Ti were studied by the stacked foil activation technique up to 37 MeV. High-resolution gamma-spectrometry measurements were performed on an HPGe detector in order to determine the activity of the irradiated Sc₂O₃ pellets and Ti monitor foils. The reaction cross-sections were measured from their respective thresholds up to E_p = 36.4 MeV and were compared with previous values reported in literature. Possible batch yields and optimal irradiation parameters for generator ⁴⁴Ti -^44gSc in high current accelerators are discussed.     

Measurement of thick target yields of the S(α,x)Cl nuclear reaction and estimation of its excitation function up to 70 MeV

Thick target yields of the ^natS(α,x)^34mCl nuclear reaction were measured in the energy region from 14.2 to 69.5 MeV. Our results were also compared to the only available literature dataset. Cross-sections of the above reaction were also estimated from the obtained thick target yields. Pure natural sulfur used as a target material resulted in a thick target saturation yield of 1557 ± 18 MBq (42.1 ± 0.5 mCi)/μA at 69.5 MeV. The estimated excitation function curve of the ^natS(α,x)^34mCl process showed a maximum cross-section of 122 mbarn at about 27.5 MeV.     

Excitation functions for some W, Ta and Hf radionuclides obtained by deuteron irradiation of Ta up to 40 MeV

Experimental excitation functions for deuteron induced reactions up to 40 MeV on mono-isotopic Ta (¹⁸¹Ta) were measured with the activation method using a stacked foil irradiation technique. From high resolution gamma spectrometry and X-ray analysis cross-section data for the production of ¹⁸¹W, ^{177,178g,180g,182m+g}Ta, and ^179m2,180mHf were determined. Comparison with the scarce earlier published data are presented and results for values predicted by different theoretical codes, adapted for more reliable calculations for d-induced reactions, are included. Thick target yields for ^{182m+g,180g,178g}Ta and ¹⁸¹W were calculated from a fit to our experimental excitation curves. Using dose conversion factors and irradiation scenarios, possible occupational doses to maintenance or scientific personnel around high power accelerators where Ta based structural elements (collimators, beam stoppers, shielding) are present could be derived.     

Differential cross-section measurements for the C(d, p0)C reaction and applications to surface analysis of materials

This work involves surface analysis by nuclear techniques, which are non-destructive, and computer simulation. The “energy analysis” method for nuclear reaction analysis is used. Energy spectra are computer simulated and compared to experimental data, giving target composition and concentration profile information. Measured values are presented for the differential cross-section of the ¹²C(d, p₀)¹³C reaction in the deuteron energy range 0.81-2.07 MeV for laboratory detection angles of 165° and 135°, using self-supported two-layered targets consisting of high purity thin films of typically 13 μg/cm² natural carbon and 65 μg/cm² gold. The error in the absolute differential cross-section values is generally ∼6%. The method, using these values, is successfully applied to determination of uniform concentration profiles of ¹²C, along considerable depths, for a thick flat target of high purity pyrolitic graphite. It is characterised a thin surface film of carbon on a thick flat quartz target. Uniform concentration profiles of ¹⁶O are also obtained from (d, p) and (d, α) reactions.     

Excitation functions of (n,p) reactions for stable isotopes of Cr,Fe and Ni from threshold to 20 MeV

The excitation functions of (n,p) reactions for the stable isotopes of Cr, Fe and Ni were calculated using EMPIRE 3.0 β1 (ARCOLE) from threshold to 20 MeV. The cross-sections are calculated using full featured Hauser–Feshbach statistical model with pre-equilibrium effects by invoking DEGAS option in the code. A good agreement between the calculated and experimental data (EXFOR data base) as well as evaluated data is obtained with option of neutron and proton potentials by Koning (Global) and HFB parity dependent nuclear level density. This is an important step to the validation of nuclear model with superior predictive power. The compound nucleus and pre-equilibrium reaction mechanisms as well as the isotopic effects were also studied.     

A comprehensive study on energy absorption and exposure buildup factors for some essential amino acids, fatty acids and carbohydrates in the energy range 0.015-15 MeV up to 40 mean free path

The gamma ray energy absorption (EABF) and exposure buildup factors (EBF) have been calculated for some essential amino acids, fatty acids and carbohydrates in the energy region 0.015-15 MeV up to a penetration depth of 40 mfp (mean free path). The five parameter geometric progression (G-P) fitting approximation has been used to calculate both EABF and EBF. Variations of EABF and EBF with incident photon energy, penetration depth and weight fraction of elements have been studied. While the significant variations in EABF and EBF for amino acids and fatty acids have been observed at the intermediate energy region where Compton scattering is the main photon interaction process, the values of EABF and EBF appear to be almost the same for all carbohydrates in the continuous energy region. It has been observed that the fatty acids have the largest EABF and EBF at 0.08 and 0.1 MeV, respectively, whereas the maximum values of EABF and EBF have been observed for aminoacids and carbohydrates at 0.1 MeV. At the fixed energy of 1.5 MeV, the variation of EABF with penetration depth appears to be independent of the variations in chemical composition of the amino acids, fatty acids and carbohydrates. Significant variations were also observed between EABF and EBF which may be due to the variations in chemical composition of the given materials.