No abstract available

[en] Determination of nitrogen by measurement of 10.82 MeV prompt gamma-rays from ¹⁴ N(n,γ)¹⁵ N reaction was investigated. A neutron irradiation system using 185 GBq (5 Ci) ²³⁸ Pu/Be source was designed and constructed. The source was installed in a 110 cm φ, 110 cm height steel tank filled with water to produce thermal neutrons. Thermal neutron beam was extracted from the top of the tank to irradiate the sample while a 5''x 5'' NaI (Tl) detector was positioned on either side of the sample. Factors that affect the measurement of 10.82 MeV gamma-rays were also studied i.e. source position, detector position and sample volume. Urea solutions with concentration ranging from 0.5 to 8 mole/l were used to calibrate the system. It was found that the net nitrogen peak intensity increased linearly with increasing nitrogen concentration. The detection limit (2σ) was found to be about 1% of nitrogen for 4000 second counting time and 7 liters of sample volume. To simulate the detection of explosives using this technique, the system was used to detect the presence of nitrogen packed inside a briefcase. The detection sensitivity was found to be about 0.1 cps per 100 grams of nitrogen

[en] A prompt gamma-ray analysis system using multiple detection method (MPGA system) was constructed at the neutron guide hall of the JRR-3M reactor of the Japan Atomic Energy Agency. We applied MPGA method to geochemical and cosmochemical samples to evaluate its analytical performance on signal to noise (S/N) ratio, sensitivity, and detection limit. The S/N ratio measured by MPGA system was larger than that by normal prompt gamma ray activation analysis (PGAA) at JRR-3M. For some elements, the S/N ratio was improved more than ten times. Several elements that are not detected by PGAA were detected by MPGA. At the present time, concentrations of major elements and trace elements with high neutron capture cross section in geochemical and cosmochemical samples were determined accurately by the MPGA system installed at JRR-3M. It is expected that it will determine a lot of trace elements after appropriate adjustments and modifications. (author)

[en] In situ current normalized Particle Induced Gamma-ray Emission (PIGE) method was used for the determination of two low Z elements namely Si and Al in 15 ancient clay pottery samples collected from two archaeological site of Tamilnadu. Samples in pellet form along with Li as in situ current normalizer were irradiated using 4 MeV proton beam from 3MV Tandetron at IOP, Bhubaneswar. Elemental concentrations ratios of SiO_2 and Al_2O_3 were used for grouping the objects. The method was validated by analyzing two USGS certified references materials (CRMs). (author)

[en] Prompt Gamma Activation Analysis (PGAA) has an advantage over most other methods in the investigation of archeological and cultural objects which must be dealt with a non-destructive method. In this study, we study about how to determine the copper-zinc fraction in archeological objects such as a smoking pipe made from brass, where the proportions of copper and zinc can be varied to create a range of brasses with varying properties. In this study, a Japanese smoking pipe was analyzed to determine the copper-zinc fraction at the KAERI-SNU PGAA facility

No abstract available

[en] We have constructed a new system which could analyze a position distribution of several elements in a sample with 2 dimensional prompt γ-ray analysis (2D PGA) system using focused neutron beam at JAEA. We aimed that the system could analyze local information in a sample with a good signal γ-ray from interested elements to noise of background γ-ray ratio. As a result, this system could determine the position resolution and spatial resolution within 1 mm. (author)

[en] We investigate the intrinsic properties of a sample of bright (with isotropic equivalent energy Eiso > 10⁵² erg) gamma-ray bursts (GRBs), comparing those with and without radio afterglow. We find that the sample of bursts with no radio afterglows has a significantly shorter mean intrinsic duration of the prompt gamma-ray radiation, and the distribution of this duration is significantly different from those bursts with a radio afterglow. Although the sample with no radio afterglow has on average lower isotropic energy, the lack of radio afterglow does not appear to be a result of simply energetics of the burst, but a reflection of a separate physical phenomenon likely related to the circumburst density profile. We also find a weak correlation between the isotropic gamma-ray energy and intrinsic duration in the sample with no radio afterglow, but not in the sample that have observed radio afterglows. We give possible explanations for why there may exist a sample of GRBs with no radio afterglow depending on whether the radio emission comes from the forward or reverse shock, and why these bursts appear to have intrinsically shorter prompt emission durations. Lastly, we discuss how our results may have implications for progenitor models of GRBs.

[en] Application of prompt gamma-activation analysis to some environmental samples and NBS's standard reference materials were examined, using NBS reactor and the technique developed by the nuclear chemistry group of the University of Maryland. Concentration of several elements, Cd, B, S, Se, Sb, Zn, Ba, Cr, Cs, Co, Si, Hf, Ce, Yb, Lu, Th, Sc, Eu, Fe, Ta and Rb, were determined by both PGAA and INAA. (author)

[en] We carried out instrumental neutron activation analysis (INAA) as well as k₀-based prompt gamma-ray analysis (k₀-PGA) to measure the amount of the elements in onions and studied whether the onions collected from different sites can be categorized based on the elemental concentration profile. Six elements (Na, Mg, Cl, K, Ca, Mn) and 3 elements (B, S, Cl) were measured by INAA and PGA in the onions grown in two districts, Hokkaido and Saga, in Japan, respectively. After principal component analysis, it was found that Cl was an important element to feature the producing districts of onions. (author)