A recently developed concept of a neutron probe (NP) -for C/O oil logging, based on associated alpha particle technique, has been developed and demonstrated by using a specially constructed NP. The NP contains a high-temperature alpha particle detector as well as a gamma detector with high energy resolution, suitable for a high-temperature environment. The probe was tested on samples collected from Croatian oil fields and on samples prepared with known C/O ratios. This NP in comparison to conventional neutron activation probes significantly reduces the background signal coming from the borehole and measures the C/O ratio depending on the azimuth angle around the borehole longitudinal axis. The time (position) resolution was found to be 2 ns enabling inspection of the C/O ratio in rock formations' layers down to 10 cm thickness. The NP was successfully tested for different environmental temperatures up to 175 degrees C. The pulse amplitude degradation coming from the gamma detector was noticed to be a function of the temperature.

The possibility of using fast 14 MeV neutrons and the associated alpha particle technique, together with a library least-squares fitting technique to detect the various CW agents as well as explosives and narcotics were investigated. The Quality Assurance/Quality Control (QA/QC) procedures for neutron sensors were established and further developed for CW agents, with the aim to reduce the false positive and false negative rates. Simulants of the various types of CW agents were prepared and measured as well as appropriate standards for measuring the ratios of chemical elements abundances: C/Cl, C/N, C/S, C/F, C/P, C/O. The influence of the measurement environment and material in which the targets were hidden was investigated.

We address a successful indirect technique, the Trojan horse method, which allows one to measure the bare nucleus cross section for rearrangement reactions down to astrophysical energies. In particular, we consider here the application of the method to the p-p elastic scattering. This represents an important test of the main feature of the method, namely the suppression of Coulomb effects in the entrance channel due to off-energy-shell effects. In contrast to the on-energy-shell case, the extracted p-p cross section does not exhibit the Coulomb-nuclear interference minimum, as predicted by the half-off-energy shell calculations. This hypothesis is strengthened by the agreement between the Trojan horse p-p data and the calculated on-energy-shell n-n, n-p and nuclear p-p cross sections.

The Trojan Horse Method (THM) was applied to the p+d interaction in order to study the p+p scattering, the simplest case where the suppression of the Coulomb amplitude due to off-shell effects can be observed. The three-body p + d -> p + p + n experiment was performed at 5 and 6 MeV and the shape of the quasi-free cross-section was investigated as a function of both the outgoing proton energy and the p-p relative energy. Preliminary results show a behaviour which turns out to be much similar to that of n+n, n+p and nuclear p+p cross-sections.

Studies of light nuclei are interesting in their own right as almost every nucleuspossesses some unique properties which reflect its structure. The varied structureswhich appear in light nuclei, from spherical shapes to prominent clustering, area considerable challenge to understand and model. It should be mentioned thatlimited and often contradictory information exists for many of them, restrictinga full understanding of their structure. However, it is well known that cluster

We have studied the ${}^{2}\mathrm{H}{(}^{6}\mathrm{Li},\ensuremath{\alpha}{)}^{4}\mathrm{He}$ two-body reaction by applying the ``Trojan horse'' method (THM) to the ${}^{6}\mathrm{Li}{(}^{6}\mathrm{Li},\ensuremath{\alpha}\ensuremath{\alpha}{)}^{4}\mathrm{He}$ three-body reaction. The astrophysical $S(E)$ factor has been extracted in the energy range between 10--800 keV for the two cases of target and projectile quasifree break-up. We found good agreement between the two data sets leading an improved determination of the $S(E)$ with $S(0)=16.9\ifmmode\pm\else\textpm\fi{}0.5 \mathrm{MeV}\mathrm{b}.$ Furthermore, the electron screening potential energy ${U}_{e}=320\ifmmode\pm\else\textpm\fi{}50$ eV has been extracted in a model-independent way by comparing direct and THM data. This value is significantly higher than the value predicted by current theoretical models.

Different aspects of clustering in beryllium nuclei, observed in experimental studies of the d+Li-7, He-6+Li-6, Li-7+Li-7 and Li-7+Be-9 reactions, are discussed.

The {sup 6}Li(d, {alpha}){sup 4}He reaction, whose astrophysical importance is connected to the primordial nucleosynthesis in the framework of the Inhomogeneous Big Bang, has been studied by using the Trojan Horse Method (THM). We derive and discuss the cross section and the astrophysical S(E)-factor for E{sub cm}=0.025-0.7 MeV. Results are compared with data from a direct measurement.

The pd break-up cross-sections for different kinematically complete configurations have been measured atE p lab = 22.7 MeV. The data are compared with predictions of the Argonne AV14, Bonn B, Nijmegen and Paris potentials. Clear discrepancies between theory and experimental data have been found, which cannot be explained by angular resolutions of the experimental set-up.

The10B(d, αα)4He reaction was studied at energies between 4.2 and 6.6 MeV in kinematical plane-star conditions with special emphasis on sequential processes through the8Be state of 11.4 MeV. The results are compared with predictions of the Quebert model.

PIXE measurements done with different proton energies provide results from which concentration depth profiles can be extracted. An aluminum sample with a known concentration depth profile of zinc was analyzed. The results presented show the usefulness of the method.

A ring-shaped, 109 Bq241Am radioisotope source was used for the excitation of K-shell X-rays from rare earth elements (56<Z<64), present in powdered geological material. In order to improve the efficiency of the measurement of these elements in the concentration range down to 10 ppm, the optimum geometry of the system was found. The results obtained are presented and discussed.

Three different modes of sample excitation in X-ray emission spectroscopy were used in trace element analysis of coal and coal ash: proton beam, Mo X-ray tube and radioactive sources 57Co and 109Cd. The results of analysis are presented and methods and their possibilities are compared in order to indicate the most appropriate technique for the particular purpose.

A forward-angle part of the 40Ca(n, 3He0)38Ar reaction angular distribution has been measured at En = 14.6 MeV. The measured cross section is much higher than activation results for the (n, 3He) reaction on some other nuclei. The differences between the cross sections of this reactions on different nuclei could be attributed mainly to Coulomb effects.

X-ray emission spectroscopy was used for analysis of coal samples. Concentrations of detected elements were determined and analysis was performed with regard to homogeneity of elements within the coal seam. Correlations between elemental concentrations were also examined.

Special kinematical conditions for nuclear reactions with three and four particles in the final state in which a large part of the available phase space could be covered by a single measurement have been discussed. The 7L(d, αα)n reaction has been measured and used for illustration.

Trace element analysis of coal, fly ash and bottom ash samples were performed using x-ray emission spectroscopy. Three different modes of sample excitation were used: proton beam, Mo-tube and radioactive sources 109Cd and 57Co. Efficiency curves and minimum detection limits were determined for all the methods used. Up to twenty elements were determined in samples analyzed.

Trace elements in human hair have been studied with different analytical methods. Some 27 elements have been identified with concentrations which vary from individual to individual and which may be caused by sex, age and color. It has been shown that trace element contents vary with geographical location, an indication of the importance of environmental effects. Because of its growth, hair reflects previous elemental concentrations in serum and body, as well as previous environmental effects. Assuming that hair growth is approximately constant and that exposure of hair to environmental elements (air, water or soil) occurs continuously, one may deduce that the elemental concentrations would increase with distance from the scalp. Indeed, some early measurements of lead concentrations along a single human hair, reported by Renshaw et al. (1972), showed an almost linear increase in the lead concentration with distance from the scalp. The same phenomenon should occur with other environmental pollutants. Therefore, the study of trace element concentrations along the hair in a group of people might give an indication of the presence of environmental pollutants.

Early investigations (Dutcher and Rothman, 1951; Goss and Green, 1955; Kikkawa et al., 1955) were mainly concerned with copper content and its relationship to color. Cotzias et al. (1964) reported small concentrations of manganese in white hair. Other investigations of trace elements and their relationships to color have been reported by Shabelnik (1966), Matheny and Dolan (1975), and Schroeder and Nason (1969).