Resonant nuclear reaction

Kalbitzer and his colleagues used the Si (p, y) resonant nuclear reaction to profile the range distribution of 10-MeV Si implanted into Ge. Figure 8 shows their experimental results (data points), along with theoretical predictions (curves) of what is expected. 

Eor a non-resonant nuclear reaction with emission of an ion, a depth scale can be obtained from the measured energy of the emitted ions. If ions emitted from a depth x are lower in energy by AE than ions emitted from the surface, a relationship between AE and x can be found, similarly to RBS and ERDA analysis ... 

NRA is a powerful method of obtaining concentration versus depth profiles of labelled polymer chains in films up to several microns thick with a spatial resolution of down to a few nanometres. This involves the detection of gamma rays produced by irradiation by energetic ions to induce a resonant nuclear reaction at various depths in the sample. In order to avoid permanent radioactivity in the specimen, the energy of the projectile is maintained at a relatively low value. Due to the large coulomb barrier around heavy nuclei, only light nuclei may be easily identified (atomic mass < 30). 

A widely used technique for depth profiling hydrogen (in this case the H isotope) uses resonant nuclear reactions (Lanford et al., 1976 Ziegler et al., 1978 Clark et al., 1978), i.e., the reaction... 

In almost every case, experimenters who use the resonant nuclear reactions have chosen to detect and count the gamma rays, but the alpha particles can also be used (Umezawa et al., 1987, 1988a). There seems to be no published comparison of the results using alpha particle and gamma ray detection. Fig 2 shows a typical experimental setup using a gamma ray detector. 

A technique which can yield hydrogen concentration profiles of a glass surface(19) without the complications of ion milling involves using the resonant nuclear reaction between hydrogen 1H) and (1 N). At precisely 6.385 M V (lab) there is a resonance in the reaction 3N + H = X +... 

One technique that has been able to measure hydrogen concentration in a thin film and do a depth profile, without reliance on standards, uses a resonant nuclear reaction technique.16 In this procedure, the nuclear reaction between a hydrogen atom ( H) and an energetic nitrogen-15 atom (1SN) is used. That is... 

Owing to a number of very suitable resonant nuclear reactions with high cross-sections and relatively unambiguous reaction products that can be used as fingerprints , fluorine has become one of the popular chemical elements... 

In the following, those ion beam analysis techniques that allow for fluorine detection will be presented. By far, the most important technique in this respect is nuclear reaction analysis (NRA). Although it can be rather complex to perform, it is the most often applied technique for fluorine trace element studies, due to a number of convenient and prolific resonant nuclear reactions which make it very sensitive to fluorine in most host matrices. NRA is often combined with particle-induced X-ray emission (PIXE) which allows for simultaneous determination of the sample bulk composition and concentrations of heavier trace elements. By focusing and deflecting the ion beam in a microprobe, the mentioned techniques can be used for two- or even three-dimensional multi-elemental imaging. 

M. Kregar, J. Muller, P. Rupnik, F. Spiler, Concentration profile measurements using multiply resonant nuclear reactions, Fizika 9 (1977) 81. 

F. Leach, H. Naylor, Dating New Zealand obsidians by resonant nuclear reactions, New Zealand J. Archaeol. 3 (1981) 33-49. 

PIGE is very sensitive (the limit of detection can be as low as 1 ppm) and non-destructive. It allows analysis of bulk F, F-distribution within one sample on cross-sections or depth profiles using resonant nuclear reaction analysis (RNRA) [35]. The spatial resolution, even using a beam of some micrometres size or RNRA, is however insufficient to detect F on individual bone crystals. The RNRA method is reviewed in detail in the chapter of Dobeli et al. [6] in this volume. 

Fig. 10. Hydrogen depth profiles obtained from the resonant nuclear reaction of an as-deposited a-Si H film and after laser annealing at different intensities. [After Thomas et al.

An important advance in understanding in detail the role of hydrogen during hydrolysis has been the use of ion-beam techniques, and particularly resonant nuclear reactions (RNR), which allow direct depth profiling of important elements such as H, Na, Al, and O. For instance, using RNR, Petit et al. (1987) and Schott and Petit (1987) have shown for the first time that pyroxene, olivine, and feldspar surfaces become protonated and/or hydrated to depths of several hundred angstroms during hydrolysis. 

Petit, J. C., G. Della Mea, J, C. Dran, J. Schott, and R. A. Berner, (1987), Diopside Dissolution New Evidence from H-Depth Profiling with a Resonant Nuclear Reaction, Nature 325, 705-706. 

Ohnuki T, Kozai N, Isobe H, Murakami T, Yamamoto S, Aoki Y, Naramoto H (1997) Sorption mechanism of emopium by apatite using Rutherford backscattering spectroscopy and resonant nuclear reaction analysis. J Nucl Sci Techn 34 58-62... 

Acronyms RNRA (resonant nuclear reaction analysis) NRA (nuclear reaction analysis)... 

RNRA, Resonant Nuclear Reaction Analysis, 35 RS Recoil Spectrometry, viz ERDA, 9 SALI Surface Analysis by Laser Ionisation, 39 SAM Scanning Auger Microscopy, 37... 

A slightly different approach uses a resonant nuclear reaction. For example, N incident on hydrogen produces a high-energy y-particle via the following reaction when the nitrogen beam is at the resonance energy, 6.385 MeV ... 

Tables 1 and 2 show some of the recently used non-resonant and resonant nuclear reactions, respectively. In general these reactions are used to depth profile the element of interest but can also be used to determine the concentration of a particular element in a sample. The following sections describe some of the many applications of NRA and ERD.

Table 2 Selected recently used resonant nuclear reactions ...

Ion implantation of materials, to change its properties, has many important applications in materials science and semiconductor technology. Several non-resonant and resonant nuclear reactions have been used for the profiling of such implantations. The 0.992 MeV resonance of the Al(p,y) Si resonant nuclear reaction has, for example, been used to profile the thermal diffusion of aluminum in aluminum-implanted stainless steel when heated to temperatures of between 450°C and 650°C. 

It is to note that A + B + C + D= 1 and AC = BD. Most nuclear reactions, called resonant nuclear reactions, have sharp resonance in the cross-section at certain energies. The resonant cross-section width is of the order of several keV. This fact is used to obtain a depth scale for the measured impurity concentration and the technique is called Resonant NRA. Reactions with suitable cross-sections exist for many elements. The N( H, ay) C nuclear reaction is widely used as a well established tool to measure hydrogen in all kinds of solids. On the other hand, in those cases where the nuclear reaction cross-sections vary slowly with energy, the technique employed is called Non-Resonant NRA. In such cases, taking NRA kinematics into account, the technique is identical to RBS. 

The ay) C resonant nuclear reaction has been used by Fallavier... 

In the analysis of light elements by PIGE, the reactions by Coulomb excitation (p, p y) are common. The resonance nuclear reactions (p, y), (p, ay) are used occasionally for the depth-profile. 

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