Complementary optical-potential analysis of alpha-particle elastic scattering and induced reactions at low energies

Effects and uses of ion beams with diamond, DLC and fullerene films

Generator nuclides constitute a convenient tool for applications in nuclear medicine. In this paper, some radiochemical aspects of generator nuclide parents regularly processed at Los Alamos are introduced. The bulk production of the parent nuclides 6 8 Ge, 8 2 Sr, 1 0 9 Cd and 8 8 Zr using charged particle beams is discussed. Production nuclear reactions for these radioisotopes, and chemical separation procedures are presented. Experimental processing yields correspond to 80%-98% of the theoretical thick target yield. Reaction cross sections are modeled using the code ALICE-IPPE; it is observed that the model largely disagrees with experimental values for the nuclear processes treated. Radionuclide production batches are prepared 1-6 times yearly for sales. Batch activities range from 40 MBq to 75 GBq.

Some nuclear chemical aspects of medical generator nuclide production at the Los Alamos hot cell facility

Maghemite nano-particles were synthesized by a solid-state chemical reaction for its highly selective use as, cyclotron-produced, 109Cd (462.9 days) purification method of choice. 109Cd radiochemical separation starts with Ag activities precipitated with HCl 0.0015 M followed by, on a second step, 109Cd separation from Cu carrier and 65Zn (243.8 days) using Ca (NO3)2 0.01 M. Experimental parameters such, pH and sorbent concentration, on 109Cd extraction efficiency were investigated. Phase morphology, nanostructure and size of nano-particles were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A 10–20 nm average grain size was derived from XRD line broadening and SEM data. Heat treatment on Fe3+:Fe2+ ratios equal to 2:1, produced powders, resulting in tetragonal (maghemite) structure at 300 °C and rhombohedra (hematite) at 600 °C. 109Cd chemical and radionuclidic purity were determined by ICP-AES and HPGe detector gamma-ray spectrometry. The overall recovery and radionuclide purity were 80.0% from obtained 129.63 kBq/C MeV (70 kBq/μAh) initial activity and 91.4%, respectively.

Synthesis of maghemite nano-particles and its application as radionuclidic adsorbant to purify 109Cd radionuclide

A simple reduction scheme using so-called reduced energies $E_{\rm{red}}$ and reduced cross sections $\sigma_{\rm{red}}$ allows the comparison of heavy-ion induced reaction cross sections for a broad range of masses of projectile and target and over a wide energy range. A global behavior has been found for strongly bound projectiles whereas much larger reduced cross sections have been observed for weakly bound and halo projectiles. It has been shown that this simple reduction scheme works also well for $\alpha$-particle induced reactions on heavy target nuclei, but very recently significant deviations have been seen for $\alpha$+$^{33}$S and $\alpha$+$^{23}$Na. Motivated by these unexpected discrepancies, the present study analyses $\alpha$-induced reaction cross sections for targets with masses $A \approx 20-50$. The study shows that the experimental data for $\alpha$-induced reactions on nuclei with $A \approx 20-50$ deviate slightly from the global behavior of reduced cross sections. However, in general the deviations evolve smoothly towards lower masses. The only significant outliers are the recent data for $^{33}$S and $^{23}$Na which are far above the general systematics, and some very old data may indicate that $^{36}$Ar and $^{40}$Ar are below the general trend. As expected, also the doubly-magic $^{40}$Ca nucleus lies slightly below the results for its neighboring nuclei. Overall, the experimental data are nicely reproduced by a statistical model calculation utilizing the simple $\alpha$-nucleus potential by McFadden and Satchler. Simultaneously with the deviation of reduced cross sections $\sigma_{\rm{red}}$ from the general behavior, the outliers $^{23}$Na, $^{33}$S, $^{36}$Ar, and $^{40}$Ar also show significant disagreement between experiment and statistical model calculation.

Cross sections of $\alpha$-induced reactions for targets with masses $A \approx 20-50$ at low energies

Excitation functions for α-induced reactions on natural vanadium were measured in the energy range up to 26.4 MeV. The stacked-foil activation technique was used to carry out the measurement. The experimental results were compared with the theoretical calculations using the exciton model, and with earlier experimental results.

Excitation functions for α-induced reactions on vanadium

Production of cadmium-107 and cadmium-109 by deuteron bombardment of silver

The excitation functions for the 107Ag(d, 2n)107Cd, 109Ag(d, 2n)109Cd and 109Ag(d, p)110mAg reactions were determined by irradiation of a natural silver target with a 13.4 MeV deuteron beam and by the stacked-foil technique. The measurement of γ-ray spectra for radioactive products was carried out by using a well calibrated HPGe detector and a low background chamber. A computer system was employed to acquire and analyse datta. The present result for the 109Ag(d, 2n)109Cd reaction was compared with those of other authors. The statistical model was applied to calculate the excitation functions for these reactions. The agreement between measured and calculated values is quite good.

Excitation functions for 107Ag(d, 2n)107Cd, 109Ag(d, 2n)109Cd and 109Ag(d, p) 110mAg reactions

By using elastic recoil detection analysis, the hydrogen concentration of amorphous carbon films prepared by ion beam deposition was determined. The dependence of the hydrogen concentration on the deposition parameters (energy of ion beam, beam current density, and ratio of hydrogen to methane in gas mixture) was observed for these films. It seems clear that the diamond cubic structure in a-C:H films increases monotonically with decreasing hydrogen concentration.

The hydrogen concentration of diamondlike amorphous carbon films by elastic recoil detection analysis

Excitation functions for alpha-induced reactions on {sup 55}Mn, {sup nat}Ag and {sup 181}Ta were measured in the energy range up to 26.5 MeV. Activation method and stacked-foil technique were used to carry out the measurements. The experimental results were compared with the theoretical calculation using the exciton model. The initial exciton number {eta}{sub o} = 4 and parameter K = 100-150 gives the best agreements with presently measured results.

Fuqing He

Papers

Excitation functions for α-induced reactions on vanadium

Production of cadmium-107 and cadmium-109 by deuteron bombardment of silver

Excitation functions for 107Ag(d, 2n)107Cd, 109Ag(d, 2n)109Cd and 109Ag(d, p) 110mAg reactions

The hydrogen concentration of diamondlike amorphous carbon films by elastic recoil detection analysis

Excitation functions for alpha-induced reactions on {sup 55}Mn, {sup nat}Ag and {sup 181}Ta