Lu Xiting

Stopping powers of C, Al, Ti, Cu, Nb and Ag for 16O and 19F ions

Abstract Stopping powers of C, Al, Ti, Cu, Nb and Ag for 0.4–5.7 MeV 16 O and 19 F ions were measured with the technique of transmission. The results were compared with the predictions of the LSS theory, SRIM2000 calculations and previous experimental data. Significant discrepancy was observed in the comparison. Apparent Z 2 -oscillation was exhibited by the present stopping power data.

Stopping power for MeV 12C ions in solids

Abstract The stopping powers for 0.3–6.4 MeV 12 C ions in C, Al, Ti, Cu, Nb and Ag have been measured with the transmission method. The experimental data on stopping power are compared with evaluated values using LSS theory, ZBL semiempirical model predictions and previous experimental data. The results show that there is significant discrepancy between present work and LSS theory; for C in Al, ZBL calculations quite agree with our measurements, yet for C in other stoppers, those cannot reproduce most of present experimental data; our work consists mostly with previous measurements. Moreover, present stopping power data exhibit apparent Z 2 -oscillation.

Stopping power for MeV energy Au ions in silicon

Abstract The range distributions of Au ions with three implanted energies (Ei=1230, 2130, 3030 keV) in silicon were measured using Rutherford backscattering technique (RBS). The projected ranges were obtained and were larger than those of the TRIM-91 calculation. The nuclear stopping power Sn calculated by Biersack general potential and the electronic stopping power Se=A(E/E0)P generated from LSS theory were used to fit the experimental data. Then the values of parameters A and P in the electronic stopping power formula Se=A(E/E0)P were determined. Significant discrepancies of the electronic stopping power between the experimental results and the TRIM-91 calculations were observed.

A new method for profiling boron

Abstract By studying the relative excitation curve of 11 B ( p , α 0 ) 8 Be , we have found that there is a wide plateau ( ∼100 keV) near the Ep = 2.62 MeV peak, which can be used to profile boron. A brief comparison between the new method and that of the 11 B ( p , α 1 ) 8 Be ∗ reaction is given.

Stopping powers of A1 for MeV Si ions

Abstract Stopping powers of A1 film for Si ions (0.8–6.4 MeV) have been measured with Rutherford backscattering (RBS) technique. A new method to determine the stopping powers for low-velocity heavy projectiles was used. The experimental results of the stopping powers for low-velocity Si ions are smaller than those of the TRIM code and LSS theory.

Depth profile of 18O at the titanium surfaces using the nuclear reaction 18O(p, α)15N

Abstract The 18 O(p, α) 15 N nuclear reaction was used to measure the depth profile of 18 O within the near-surface region of titanium. The measurements were performed usig a 2 × 1.7 MV tandem accelerator. To reduce the depth resolution value Δx, the target was tilted. A good depth resolution Δx ≈ 30 nm within the surface (⩽ 200 nm) of titanium was obtained. The Fourier-transformation method was used in the data processing.

Enhancement in Energy Loss of MeV Silicon Clusters in C Films

Energy losses of 0.63-1.03 MeV/atom Sin (n≤3) clusters in thin carbon films (2-12µg/cm2) have been measured by using a special experimental set-up with the Rutherford backscattering (RBS) technique. The experimental results show that, for a given energy per atom, the energy loss of Si2+ ions, as well as Si3+ ions, is significantly larger than that of Si+ ions. This is the first observation of energy loss enhancement in measurements with the RBS technique. The enhancement in energy loss (i.e. the cluster effect) is evident enough when the effective thickness of the carbon target is thin, but not evident when it is thick. The effect will not be obvious until the energy of the projectile is over a certain limit for a special target. This suggests that the cluster effect only occurs in the first layers of the target film, and that the energy of the projectile must be large enough for the effect to be seen.

Stopping Powers of Bromine and Carbon in Silver

The stopping powers of Br and C in Ag film have been measured with the method of elastic recoil detection in energy range 0.28-0.42 MeV/amu. The results have been compared with the theoretical calculations of TRIM-90.

DSA measurement using heavy ion reactions on the small tandem accelerator

Abstract The lifetimes of the 7.12 MeV level in 16 O and the 4.44 MeV level in 12 C have been measured using the Doppler shift attenuation method at a small accelerator. The reversed nuclear reactions 1 H( 19 F, α) 16 O ∗ and 1 H( 11 B, γ) 12 C ∗ were used.

HYDROGEN PROFILING IN SOLIDS BY RESONANCE NUCLEAR-REACTIONS

Abstract Hydrogen profiling by resonance nuclear reactions of 1H(19F, aγ) 160 and 1H(7Li, γ)8Be with the resonance energy of 6.42 and 3.07 meV respectively with very good depth resolution has been performed. The measurements have been carried out at a small tandem accelerator of 2 × 1.7 MV with multicharged ion beams. The comparison of these two reactions and a number of applications to amorphous silicon (a-Si) and multilayer solid samples are presented in this paper.