Alpha induced reactions on Cd and Cd: An experimental study of excitation functions

Excitation functions of alpha induced reactions on enriched ¹¹⁴Cd and ¹¹⁶Cd targets, leading to the formation of the ^117m,119mSn, ^{114m₁,115m,116m,117m,g}In, ^115gCd isotopes, were studied by the stacked foil activation technique. Reaction cross-sections were measured from their respective thresholds up to E_α = 38.9 MeV. Quantification of induced isotopes has been made by gamma and X-ray spectrometry. The experimental cross-sections are compared, where available, with values reported previously in literature. Thick target yield for the medically important radionuclide ^117mSn is calculated based on discrete values of measured cross-sections.     

New measurement and evaluation of the excitation function of Ni(p,n) reaction for the production of Cu

One of the radioisotopes for which a growing interest exists in nuclear medicine is ⁶⁴Cu. Its branched decay makes it suitable for both diagnostic and therapeutic purposes. Activation cross sections of the proton induced reaction on enriched ⁶⁴Ni have been studied using the stacked foil technique up to 24 MeV. The experimental cross sections are compared with values available from literature. Thick target yields, based on the discrete measured values of the cross sections are calculated and allow a better estimation of the optimum production parameters.     

Excitation functions of proton induced nuclear reactions on W up to 40 MeV

We measured the excitation functions for the production of the ^{181,182m,182g,183,184g,186}Re radioisotopes from proton bombardment of natural tungsten by using a stacked-foil activation technique in the energy range from threshold energy to 40 MeV at the MC50 cyclotron of the Korea Institute of Radiological and Medical Science. The results were compared with the earlier reported experimental data and the model calculations using codes TALYS and ALICE-IPPE. The present values are in good agreement with some of the previously reported literature. The integral yields for thick targets were also deduced from the measured excitation functions of the produced radioisotopes. The deduced yield values were compared with the available directly measured thick target yield, and found acceptable agreement. The investigated radioisotope ¹⁸⁶Re has remarkable applications in the field of nuclear medicine, whereas the data of ^183,184gRe have potential applications in thin layer activation analysis.     

Study of proton induced reactions on niobium targets up to 70 MeV

Niobium is a metal with important technological applications: use as alloying element to increase strength of super alloys, as thin layer for tribological applications, as superconductive material, in high temperature engineering systems, etc. In the frame of a systematic study of activation cross-sections of charged particle induced reactions on structural materials proton induced excitation functions on Nb targets were determined with the aim of applications in accelerator and reactor technology and for thin layer activation (TLA). The charged particle activation cross-sections on this element are also important for yield calculation of medical isotope production (^88,89Zr,^86,87,88Y) and for dose estimation in PET targetry. As Niobium is a monoisotopic element it is an ideal target material to test nuclear reaction theories. We present here the integral excitation functions of ⁹³Nb(p,x)^90,93mMo, ^92m,91m,90Nb, ^86,88,89Zr, ^86,87mg,88Y and ⁸⁵Sr in the energy range 30-70 MeV, some measured for the first time at this energy range.The results were compared with the theoretical cross-sections calculated by means of the code ALICE-IPPE and with the literature data. The calculations have been carried out without any parameter adjustment. The theory reproduces the shape of the measured results well and magnitude is also acceptable.Thick target yields calculated from our fitted cross-section give reliable estimations for production of medically relevant radioisotopes and for dose estimation in accelerator technology.     

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.     

Investigation of excitation functions of alpha induced reactions on Xe: Production of the therapeutic radioisotope Cs

Excitation functions were measured for alpha-particle induced nuclear reactions on natural xenon leading to the formation of the radionuclides ^{129m(rel),129g,131m,131mg,133m,135m,137m,139cum}Ba and ^{129cum,130mg,132,134m,135m,136mg,138mg}Cs from the respective thresholds up to 40 MeV. No earlier experimental cross section data were found in the literature. The experimental data were compared to and analyzed with the results of the theoretical model code ALICE-IPPE. The feasibility of the production of the therapeutic radioisotope ¹³¹Cs by using gas target technology was investigated. Comparison of reactor and cyclotron production routes of ¹³¹Cs was given.     

Excitation functions of the proton-induced nuclear reactions on Sn up to 40 MeV

We have measured the production cross-sections of the residual radionuclides for proton-induced reactions on natural tin by using a stacked-foil activation technique in the energy range from threshold energy to 40 MeV at the MC-50 cyclotron of the Korea Institute of Radiological and Medical Sciences. The results were compared with the earlier reported experimental data and theoretical calculations based on the TALYS and the ALICE-IPPE codes. The present results are in general good agreement with the available literature data and calculated results by using the computer codes TALYS and ALICE-IPPE. The thick target integral yields were also deduced from the measured excitation functions of the produced radionuclides.     

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.     

Production cross-sections of residual radionuclides from proton-induced reactions on Ag up to 40 MeV

We measured the cross-sections of the ^{104g,105,106m}Ag and ^104,107Cd radionuclides produced by proton-induced reactions on natural silver by using a stacked-foil activation technique in the energy range from a threshold energy to 40 MeV at a MC50 cyclotron. The results showed generally good agreement with available data as well as the theoretical data. The integral yields for thick targets were also deduced using the measured cross-sections and the stopping power of ^natAg over the energy range from a threshold energy to 40 MeV, taking into account that the total energy is absorbed in the targets. The production cross-sections for the ^104gAg and the ¹⁰⁴Cd radionuclides from natural silver were measured for the first time.     

Differential cross-sections for nuclear reactions on Al and Si induced by deuterons at low energy (1-2 MeV)

Recent progress in thin film techniques has made possible the fabrication of stable and pollution-free reference standards. Thin Si₃N₄ film (thickness 70 nm) and thin Al foil (150 nm) were selected to measure the differential cross-sections of nuclear reactions induced by deuterons, from 1 to 2 MeV. The absence of oxygen and carbon in the standard, as well as the stoichiometry, were checked prior to measurement by RBS. The differential cross-sections of the ²⁷Al(d,p₀p₁)²⁸Al, ²⁷Al(d,p₂p₃)²⁸Al, ²⁷Al(d,p₅p₆)²⁸Al, ²⁷Al(d,p₉)²⁸Al, ²⁷Al(d,p₁₀)²⁸Al, ²⁷Al(d,p₁₁)²⁸Al, ²⁷Al(d,p₁₂)²⁸Al, ²⁷Al(d,α₀)²⁵Mg and ²⁷Al(d,α₂)²⁵Mg reactions for aluminium and ²⁸Si(d,p₀)²⁹Si- ²⁹Si(d,p₁)³⁰Si, ²⁸Si(d,p₁)²⁹Si- ²⁹Si(d,p₂)³⁰Si, ²⁸Si(d,p₂)²⁹Si, ²⁸Si(d,p₃)²⁹Si, ²⁸Si(d,p₉p₁₀)²⁹Si reactions for silicon were determined for a detector angle of 150°.     

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.     

Production cross-sections for the residual radionuclides from the Cd(p, x) nuclear processes

We measured the production cross-sections of the ^{107,111m,115g}Cd, ^{108m,108g,109g,110m,110,111g,113m,114m,115m,116m}In and ^{104g,105g,106m,110m,111g,113g}Ag radionuclides for proton-induced reactions on cadmium by using a stacked-foil activation technique in the energy rangy between 3 and 40 MeV at the MC-50 cyclotron of the Korea Institute of Radiological and Medical Science. The measured cross-sections were compared with the available literature data and the theoretical calculations by the model codes TALYS and ALICE-IPPE. The integral yields for thick targets were also obtained from the measured cross-sections of the produced radionuclides. The measured cross-sections, especially the indium (In) radionuclides have a significance for various practical applications; thin layer activation analysis, nuclear medicine, nuclear technology, radioactive waste handling, etc.     

Investigation of the Zn(p, 2p)Cu nuclear reaction: New measurements up to 40 MeV and compilation up to 100 MeV

The excitation function was measured for the ⁶⁸Zn(p, 2p)⁶⁷Cu nuclear reaction from its threshold energy up to 40 MeV. Nine pieces of highly enriched ⁶⁸Zn (>98%) metal foils were irradiated to obtain reliable cross-sections using the usual stacked-foil technique. All foils were subjected to high efficiency radiochemical separation before the activity measurements. A critical compilation of the available experimental cross-section results was also performed. Thick target yields of ⁶⁷Cu and the longer-lived copper radio-contaminants (⁶¹Cu and ⁶⁴Cu) were calculated using the reliable literature results up to 100 MeV. Additionally, EOB (End Of Bombardment) contamination levels as a function of bombarding energy and irradiation time were deduced.     

Cross-sections for alpha particle produced radionuclides on natural silver

Alpha particle-induced nuclear reactions for the generation of radionuclides on natural silver targets were investigated with the stacked foil activation technique up to E_α = 40 MeV. Elemental excitation functions are reported for the reactions ^natAg(α,xn)^{108,109,110,111}In, ^natAg(α,2pxn)^{105,106,110,111}Ag and ^natAg(α,pxn)^111mCd. The experimental cross-sections were compared with available data. Thick target yields have been deduced using the reported excitation functions.     

The (He, tf) as a surrogate reaction to determine (n, f) cross sections in the 10-20 MeV energy range

The surrogate reaction ²³⁸U(³He, tf) is used to determine the ²³⁷Np(n, f) cross section indirectly over an equivalent neutron energy range from 10 to 20 MeV. A self-supporting ∼761 μg/cm² metallic ²³⁸U foil was bombarded with a 42 MeV ³He²⁺ beam from the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory (LBNL). Outgoing charged particles and fission fragments were identified using the Silicon Telescope Array for Reaction Studies (STARS) consisted of two 140 μm and one 1000 μm Micron S2 type silicon detectors. The ²³⁷Np(n, f) cross sections, determined indirectly, were compared with the ²³⁷Np(n, f) cross section data from direct measurements, the Evaluated Nuclear Data File (ENDF/B-VII.0), and the Japanese Evaluated Nuclear Data Library (JENDL 3.3) and found to closely follow those datasets. Use of the (³He, tf) reaction as a surrogate to extract (n, f) cross sections in the 10-20 MeV equivalent neutron energy range is found to be suitable.     

Activation cross sections of proton induced nuclear reactions on ytterbium up to 70 MeV

Cross sections of proton induced nuclear reactions on ytterbium were measured up to 70 MeV by using the standard stacked foil irradiation technique and high-resolution gamma-ray spectroscopy. Experimental cross sections and derived integral yields are reported for the first time for the ^natYb(p,xn)^{173,172mg,171mg,170,167}Lu, ^natYb(p,x)^{175cum,166cum}Yb and ^natYb(p,x)^{173ind,172ind,168,167cum,165cum}Tm reactions. No earlier experimental cross section data were found in the literature. The experimental data were compared to and analyzed with the results of the theoretical model code ALICE-IPPE. Production routes of medical radioisotope ¹⁶⁷Tm are discussed.     

Measurement of cross-sections for the (p, xn) reactions in natural molybdenum

Cross-sections for the residual radionuclide productions by proton-induced activation on natural molybdenum were measured up to 40 MeV by using a stacked-foil technique at the MC50 cyclotron of the Korea Institute of Radiological and Medical Sciences (KIRAMS). This work has given a new data set for the formation of the investigated radionuclides. The present results for most of the radionuclides showed in general good agreement with the earlier reported data as well as the theoretical data taken from the calculations based on the ALICE-IPPE code. The integral yields for thick targets were also deduced from the measured cross-sections of the produced radionuclides. The optimum production of the ^99mTc radionuclide with minimum impurities can be obtained at the energy ranges from 10 to 23 MeV, where the production yields were obtained as 597.15 MBqμA⁻¹h⁻¹ at saturation. The measured cross-sections are used for production of medically important radionuclides such as ^99mTc, ^94mTc and ^93m,gTc by using the medium-energy cyclotrons.     

Neutron interrogation of high-enriched uranium by a 4 MeV linac

For revealing unauthorized transport (illicit trafficking) of nuclear materials, a non-destructive method reported earlier, utilizing a 4 MeV linear accelerator for photoneutron interrogation, was further developed. The linac served as a pulsed neutron source for assay of highly enriched uranium. Produced in beryllium or heavy water by bremsstrahlung, neutrons subsequently induced fission in the samples. Delayed neutrons were detected by a newly designed neutron collar built up of 14 ³He counters embedded in a polyethylene moderator. A PC controlled multiscaler served as a time analyzer, triggering the detector startup by the beam pulse. Significant progress was achieved in enhancing the detector response, hence the sensitivity for revealing illicit material. A lower sensitivity limit of the order of 10 mg ²³⁵U was determined in a 20 s measurement time with a reasonable amount of beryllium (170 g) or of heavy water (100 g) and a mean electron current of 10 μA. Sensitivity can be further enhanced by increasing the measurement time.     

Evaluated activation cross sections of longer-lived radionuclides produced by deuteron induced reactions on natural iron up to 10 MeV

Charged particle induced reactions can be used to monitor in real time the wear of mechanical structures such as internal combustion engines and turbines. Charged particle induced reactions with suitable properties also can be used for monitoring the actual parameters of bombarding particle beams. One of these reactions is the ^natFe(d,x)⁵⁷Co process. The available experimental data in the literature are well established around and above the maximum of the excitation function, however only a little, scattered data are available in the threshold energy region of the reaction. In this work we measured the excitation functions of relevant processes resulting in ^55,56,57,58Co, ⁵⁹Fe and ^52,54Mn induced by deuteron beams on natural iron in the energy range from threshold up to 10 MeV. The new experimental data collected are used to determine with high confidence recommended values for the missing low energy part of the investigated excitation functions.