24Na Reaction Research Articles

Production of the isotope 18F in the reaction 23Na(γ,αn)18F at E b = 55 MeV

The activity of 18F that was produced in the 23Na(γ,αn)18F reaction with the maximum bremsstrahlung energy E b = 55 MeV was measured.

Cross section measurements for 141Pr(n,γ)142Pr reaction at neutron energies from 13.5 to 14.8 MeV

Activation cross-sections were measured for the 141Pr(n,γ)142Pr reaction at three different neutron energies from 13.5 to 14.8 MeV. The fast neutrons were produced via the 3H(d,n)4He reaction on Pd-300 neutron generator. The natural high-purity Pr2O3 powder was used as target material. Induced gamma activities were measured by a high-resolution gamma-ray spectrometer with high-purity germanium detector. Measurements were corrected for gamma-ray attenuations, random coincidence (pile-up), dead time and fluctuation of neutron flux. The neutron fluences were determined by the cross section of 27Al(n,α)24Na 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. The data for 141Pr(n,γ)142Pr reaction cross sections are reported to be 3.3 ± 0.2, 2.7 ± 0.2 and 2.2 ± 0.2 mb at 13.5 ± 0.2, 14.1 ± 0.2, and 14.8 ± 0.2 MeV incident neutron energies, respectively. Results were discussed and compared with some corresponding values found in the literature.

Measurements of (n, 2n) Reaction Cross Sections at 14 MeV for Several Nuclei

Measurements of (n, 2n) reaction cross sections to produce 84Rb, 86Rb, 88Y, 139Ce, 141Ce, 168Tm, 174m+gLu, 180mTa, 184m+gRe, 196n+gAu, and 237U were carried out in the range of 13.4 to 14.8 MeV. The samples were irradiated at various positions on the surface of a two-ring orientation instrument with a 20-cm radius centered at the deuterium-tritium neutron source. The 27Al(n,α)24Na reaction was used to monitor the neutron fluence in the target samples. The neutron energies of different directions were determined using the ratio of 89Zr to 92mNb specific activities induced in Zr and Nb foils by (n, 2n) reactions. The (n, 2n) products were measured using a calibrated Ge detector. Experimental uncertainty was within ±4%. The results are presented and compared with the results of references and ENDF/B-VII.0 evaluations. Cross sections of 85Rb(n, 2n)84Rb, 140Ce(n, 2n)139Ce, and 89Y(n, 2n)88Y were in good agreement with those of ENDF/B-VII.0 evaluations; however, disagreements were observed for 175Lu(n, 2n)174Lu and 142Ce(n, 2n)141Ce between the present data and the ENDF/B-VII.0 evaluation file. The present data showed improvement in accuracy in comparison with previously reported data; therefore, the results should be offered for evaluations of neutron (n, 2n) cross sections.

Cross sections of deuteron induced reactions on 45Sc up to 50 MeV: Experiments and comparison with theoretical codes

Although Sc is not often used as alloying element in structural materials around charged particle accelerators, activation characteristics for possible production of longer lived Sc radioisotopes, used in biomedical applications and as tracers are needed. Cross sections for production of 46,44m,44g,43Sc and 45,44Ti were measured between the reaction thresholds and 50 MeV. A stacked foil irradiation followed by high resolution gamma spectroscopy was used. Reduced uncertainty was obtained by simultaneous remeasurement of the Al(d,x) 24Na or natNi(d,x) 61Cu monitor reaction over the whole energy range. A comparison with scarce experimental literature values and results of updated theoretical codes (ALICE-D, EMPIRE-D and the TENDL2010 online library) is discussed. Thick target yields for the medically relevant isotopes 46,44mSc are presented and a discussion of production routes of the very long lived 44Ti ( T 1/2 = 60 y)( 44gSc generator) is made.

Cross sections of deuteron induced reactions on natCr 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.

Measurements of activation cross sections for 175Lu(n, α) 172Tm, 176Lu(n, α) 173Tm and 175Lu(n, p) 175m+gYb reactions induced by neutrons around 14 MeV

The cross sections for the 175Lu(n, α) 172Tm, 176Lu(n, α) 173Tm and 175Lu(n, p) 175m+gYb reactions have been measured in the neutron energy range of 13.5–14.8 MeV using the activation technique. The first data for 175Lu(n, α) 172Tm reaction cross sections are presented. In our experiment, the fast neutrons were produced via the 3H(d, n) 4He reaction on K-400 Neutron Generator at Chinese Academy of Engineering Physics (CAEP). Induced gamma activities were measured by a high-resolution (1.69 keV at 1332 keV for 60Co) 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 fluences were determined by the cross section of 93Nb(n, 2n) 92mNb or 27Al(n, α) 24Na reactions. The neutron energy in the measurement was by the cross section ratios of 90Zr(n, 2n) 89m+gZr and 93Nb(n, 2n) 92mNb reactions. The results were discussed and compared with experimental data found in the literature and with results of published empirical formulae.

Cross section measurements for (n, p) reaction on stannum isotopes at neutron energies from 13.5 to 14.6 MeV

Utilizing the cross sections for 93Nb(n, 2n)93mNb or 27Al(n, a)24Na reactions as monitors, the cross sections for the reactions 115Sn(n, p)115mIn, 116Sn(n, p)116mIn, 117Sn(n, p)117 In and 117Sn(n, p)117mIn have been measured at neutron energy ranging from 13.5 to 14.6 MeV through activation technology. Then, the results of present work were compared with the published experimental data.

Investigation of cross sections of reactions used in neutron activation analysis

Abstract In this study, neutron incident reaction cross sections for some target nuclei such as 24Mg, 27Al, 28Si, 56Fe, and 63Cu used in neutron activation analysis have been investigated. The new calculations on the excitation functions of 24Mg(n, p)24Na, 27Al(n, p)27Mg, 27Al(n, α)24Na, 28Si(n, p)28Al, 56Fe(n, p)56Mn, and 63Cu(n, 2n)62Cu reactions have been carried out for incident neutron energies up to 20 MeV. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the new geometry dependent hybrid model and the full exciton model. Equilibrium effects are calculated according to the Weisskopf–Ewing model. In the present work, reaction cross-sections have been calculated by using empirical formulas developed for energies of 14–15 MeV. The calculated results are discussed and compared with the experimental data taken from the EXFOR database.

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 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.

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.

Experimental studies on deuteron-induced activation reactions in IFMIF accelerator structural elements

In order to improve the quality of deuteron-induced activation data required for the safety design of the IFMIF (International Fusion Materials Irradiation Facility), we have measured (1) the activation cross-section of natLi(d,x)7Be in the deuteron-energy range from 7 to 39MeV and (2) the production rates of radioactive nuclides in thick targets for natLi(d,x)7Be, natC(d,x)7Be, and 27Al(d,x)7Be, 22Na, 24Na reactions at 40MeV using the AVF cyclotron of Tohoku University. We have also estimated the production rates of these nuclides in the thick targets below 40MeV using the cross-sections obtained in this study.The present data compared favorably with other experimental data, IAEA-recommended data, and the data obtained using the recent nuclear reaction code TALYS and the activation code IRACM, which is based on the ALICE-F code. Some calculation results showed marked disagreement with the experimental data.

O9 Chlorin e6 photosensitizer as a fluorescence marker for fluorescence diagnostics during photodynamic therapy in ophthalmology

A relationship is presented which permits a determination of the quantity Γϱ2/Γ, where Γϱ and Γ are the particle (proton) and total widths, respectively, of an isolated resonance of which the total spin and channel spin mixing parameter are known. The analysis depends upon observation at a zero of the relevant Legendre polynomial, and hence only resonances for which ≠ can be analysed. Since the relationship is independent of instrumental resolution, it can be expected to yield better values of the parameters than the usual curve fitting procedure. The results are independent of target thickness, counter efficiency and solid angle, and current integrator precision. The formula given is valid if there is no appreciable l-mixing, no overlap of resonances, and if the “hard-sphere” correction to the Rutherford scattering is negligible. Tables are given showing where the latter approximation may be expected to break down. The restriction on l-mixing can be removed if the parity allowed l's are odd, since observation at 90° (C.M.) makes all interference terms vanish. If the allowed l's are even it is still possible to apply the formula given if an angle of observation can be found where the interference terms vanish. In both cases difficulty will be encountered in evaluating the results since the l-mixing parameter must be known. It is also shown that if the off-resonant scattering can be quantitatively compared to the Rutherford scattering, the range of application of the formula can be extended to cover all well-separated resonances. The extended formula depends, however, on the constancy (not the absolute value) of target thickness, counter efficiency and solid angle, and current integrator calibration. The analysis is applied to published data on the elastic scattering at a bombarding energy of 1.286 MeV in the 23Na (ϱ, ϱ) reaction.

Study of the hindrance effect in sub-barrier fusion reactions

We have measured the fusion cross sections of the 12C( 13C, p) 24Na reaction through off-line measurement of the β decay of 24Na using the β- γ coincidence method. Our new measurements in the energy range of E c . m . = 2.6 – 3.0 MeV do not show an obvious S-factor maximum but a plateau. Comparison between this work and various models is presented.

Experimental measurements of Na-24 activity in Tehran Research Reactor (TRR)

Experimental determination of coolant activity due to Na-24 produced as a result of 23Na(n,γ) 24Na and 27Al(n,α) 24Na reactions has been done for TRR. Activity of various water samples from the reactor pool was measured. Relative Source Strength Measurement (RSSM) technique was employed to measure Na-24 activity. It showed that the total activity per unit volume due to Na-24 in the reactor pool is 124.01 ± 3 Bq/cm 3. The activity due to 23Na(n,γ) 24Na reaction in coolant was also determined using the RSSM method and its value is 43.42 ± 0.8 Bq/cm 3. Therefore the measured activity due to recoil Na-24 is 80.59 ± 1.1 Bq/cm 3. It agrees well the theoretical predictions of 120.62 Bq/cm 3 for same reactor operating conditions. These results validate assumptions made in development of coolant activation model, i.e., the fraction of Na-24 that enters the coolant as recoil product is 0.25 and about 90% of the water leaving the core mixes uniformly with the coolant in reactor pool whereas the returns immediately back to the core inlet.

Validation of CASCADE code using the monitor reactions

Production cross-sections of monitor reaction 27Al(x, y)24Na for proton, neutron and deuteron projectiles have been estimated from the CASCADE code from tens of MeV/n to tens of GeV/n energy and compared them with the available experimental data. It has also been shown that using the CASCADE code production cross-section of 27Al(d, y2)24Na reaction can be obtained from the proton and neutron projectiles. Implicitly, this provides an alternative way of knowing production cross-section of 27Al(n, y 1)24Na reaction which may be used to monitor the neutron flux in a wide range of energy. However, in the paper need of experimental determination of cross-sections for neutron projectile has been stressed. Similarly, cross-section of other monitor reactions like 27Al(p, y ′)22Na and 27Al(n, y ′ 1)22Na are also calibrated as function of energy up to several GeV.

14.8 MeV Neutron Activation Cross Section Measurements for Ge Isotopes

The cross sections of Ge isotopes were measured with the activation method at 14.8 MeV neutron energy. The quasi-monoenergetic neutron beams were produced via the 3H(d,n)4He reaction at the 150 kV J-25 neutron generator of INST, AERE. The characteristics γ-lines of the product nuclei were measured with a closed end coaxial 17.5 cm2 high purity germanium (HPGe) detector gamma ray spectroscopy. The cross sections were determined with reference to the known 27Al(n,α)24Na reaction. Cross section data are presented for 72Ge(n,p)72Ga, 74Ge(n,α)71mZn and 76Ge(n,2n)75m+gGe reactions. The cross section values obtained for the above reactions were 24.78±1.75 mb, 1.69±0.11 mb and 860±50 mb, respectively. The results obtained were compared with the values reported in literature as well as theoretical calculation performed by the statistical code SINCROS-II. The experimental data were found fairly in good agreement with the calculated and literature data. Keywords: Activation cross section; Neutron induced reaction; Gamma-ray spectroscopy; 14.8 MeV. © 2009 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v1i2.1532

Double differential cross-sections of ( [formula omitted]) reactions in aluminium and nickel at 14.77 MeV neutrons

The double differential cross-sections (DDX) for the emission of alpha particles from 27Al( n , α ) 24Na and Ni( n , α ) reactions induced by 14.77 MeV neutrons were estimated from the alpha particle spectra recorded at 30°, 50°, 90°, 110° angles for aluminium, and at 20°, 45°, 90°, 110° for natural nickel. The results indicate that the alpha particles below and around the most probable energies (∼6.3 MeV from aluminium and ∼8 MeV from natural nickel) are emitted predominantly through the compound nucleus formation process, and the higher energy alpha particles are emitted through the pre-equilibrium or the direct reaction. In general, the measured double-differential cross-sections are in agreement with the theoretical cross-sections estimated using Talys-1.0 and Preco2007 computer programs. The present value of the level density parameter for 24Na is close to the literature value and, therefore, these results reveal consistency in the alpha particle spectra recorded with a single silicon surface barrier detector at different scattering angles.

Neutron induced reaction cross sections for the radioactive target nucleus 99Tc

We present the first measured and interpreted excitation functions for three nuclear reactions on the radioactive target nucleus 99Tc over the energy range from threshold to 20.6 MeV. Excitation functions for the 99Tc( n , n ′ γ ) 99mTc, 99Tc( n , p ) 99Mo, and 99Tc( n , α ) 96Nb reactions were measured using the activation method. High-resolution γ-ray spectroscopy was used requiring special attention to suppress Bremsstrahlung. The irradiated samples consisted of pressed pellets of metallic 99Tc in Al-capsules. Quasi mono-energetic neutrons were produced via the 3H( p , n ) 3He, 2H( d , n ) 3He, and 3H( d , n ) 4He reactions. The neutron fluence was monitored via the well-known 115In( n , n ′ ) 115mIn, 27Al( n , α ) 24Na, 27Al( n , p ) 27Mg, 56Fe( n , p ) 56Mn, and 93Nb( n , 2 n ) 92mNb standard reactions. Statistical model calculations incorporating precompound effects were performed for all the measured reaction channels using two different codes, namely TALYS and STAPRE. Good agreement was obtained for the reactions in which a charged particle was emitted and for the excitation of the isomer in inelastic scattering, above 5 MeV.

The determination of reactor neutron spectrum-averaged cross-sections in miniature neutron source reactor facility

A comparator method based on the resonance integral of 197Au(n, γ) 198Au reaction has been used to determine fast neutron spectrum-averaged cross-section data of some dosimetry reactions in a miniature neutron source reactor (MNSR) facility. Target materials of low- and medium-mass nuclei, which are of interest in reactor dosimetry and NAA were investigated. Irradiation was performed under Cd cover in an inner irradiation channel of the Nigeria Research Reactor-1 (NIRR-1) currently fueled with highly enriched uranium (HEU). Spectrum-averaged cross-section data were calculated on the basis of the epithermal neutron flux monitored by the Al–0.1%Au foil irradiated along with the target materials. Results of (n,p) reaction on 27Al, 28Si, 29Si, 46Ti, 47Ti, 56Fe, 58Ni, and (n, α) reaction on 30Si were found to be in good agreement with recommended data within standard deviation. However, data obtained for the 27Al(n, α) 24Na and 64Zn (n,p) 64Cu reactions using the Al–0.1%Au foil as the flux monitor for both the comparator approach and the conventional method are higher than recommended data from the literature by over 25%.