The IREN facility at the Frank Laboratory of Neutron Physics (FLNP) of the Joint Institute for Nuclear Research (JINR) is used for experiments to determine elemental composition of various samples by neutron activation analysis (NAA). A pneumatic transport system (PTS) REGATA-2 was implemented to automate the delivery of containers with samples to the irradiation position and back. The article describes the characteristics of the PTS, its adaptation for operation at the IREN facility, and also plans for subsequent modernization and future prospects. After the assembling of the system, the optimal parameters were chosen for irradiating the typical samples, and a calibration was created for a high-purity germanium detector, which let to consider the volume nature of the samples. Samples of archaeological ceramics from Kazakhstan were studied using the PTS. The features of the IREN facility let to use not only a neutron, but also a gamma-producing target. The first experiments on the qualitative determination of elements by gamma-activation analysis (GAA) were carried out, and the prospects for using the facility for these purposes were confirmed. The creation of the PTS let to automate the process of irradiation samples and increase the efficiency of research in NAA and GAA, especially for short-lived isotopes. It also reduces the negative impact of radiation on the human body.

The new experimental setup has been built at the 11b channel of the IBR-2 research reactor at FLNP, JINR, to study the elemental composition of samples by registration of prompt gamma emission during thermal neutron capture. The setup consists of a curved mirror neutron guide and a radiation-resistant HPGe high-purity germanium detector. The detector is surrounded by lead shielding to suppress the natural background gamma level. The sample is placed in a vacuum channel and surrounded by a LiF shield to suppress the gamma background generated by scattered neutrons. This work presents characteristics of the experimental setup. An example of hydrogen concentration determining in a diamond powder made by detonation synthesis is given and on its basis, the sensitivity of the setup is calculated being ∼4 μg.

The first experiments were carried out to study the elemental composition of archaeological ceramics using prompt gamma activation analysis (PGAA) at the pulsed reactor IBR-2, Frank Laboratory of Neutron Physics (FLNP) - Joint Institute for Nuclear Research (JINR). A radiation-resistant n-type High Purity Germanium (HPGe) detector was used to measure the radioactivity. The concentrations of 14 elements were determined namely; Al, C, Ca, Fe, Gd, H, K, Mn, Na, P, S, Si, Sm, and Ti. The obtained results were compared with those analyzed by other analytical techniques INAA (Instrumental Neutron Activation Analysis) and portable X-ray fluorescence (XRF) for the same archaeological batches. The results revealed a good agreement within a range of 1-30%. These insights will contribute to the discussion of improving the PGAA installation and automation of the data obtained, which in turn will improve the quality of analysis and increase the number of determined elements. In this work results are presented, and the analytical merits are compared.

In the study of the Chelyabinsk meteorite fragment various non-destructive neutron methods, such as prompt gamma-ray activation analysis and neutron diffraction texture analysis were used. These methods are realized by the special spectrometers which are operating at the neutron beams of the IBR-2 pulsed reactor (Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna, Russia). Applying prompt gamma-ray activation analysis, mass fractions of 15 elements: Na, Mg, Al, Si, S, Cl, K, Ca, Sc, Ti, Cr, Mn, Fe, Co, and Ni were determined. The fragment surface was analyzed by the X-ray fluorescence. The data obtained are in agreement with previously published ones, as well as with the results of texture analysis. For the first time the detailed quantitative texture analysis of Chelyabinsk meteorite fragment was performed. The method provides to obtain preferred orientations of main minerals of meteorite fragment. A suggestion was made regarding the origin of texture as a result of thermobaric impact of the meteorite when it enters the Earth’s atmosphere.

It is possible to describe the scattering and the radiative capture with help of a Breit-Wigner resonance with negative energy.

The paper describes the software for automated quantitative determination of the mass fractions of elements in the samples under investigation based on the absolute method of neutron activation analysis. The software is used during NAA at the IBR-2 reactor and the IREN research facility in the Frank Laboratory of Neutron Physics at the Joint Institute for Nuclear Research. The software can be used in any laboratories carrying out NAA.

An elemental analysis of the Tsarina Anastasia Romanovna hair fragments from the Moscow Kremlin necropolis has been carried out. The mass fractions of elements were determined by several methods: neutron activation analysis (using three facilities – the IBR-2 reactor, the IREN research facility, Joint Institute for Nuclear Research, Russia; and the WWR-K reactor, Institute of Nuclear Physics, Republic of Kazakhstan), inductively coupled plasma mass spectrometry, and atomic emission spectroscopy (Institute of Nuclear Physics, Republic of Kazakhstan). The results confirmed the hypothesis of mercury poisoning of the first Russian Tsarina Anastasia Romanovna.

The article is devoted to the first attempt to use neutron activation analysis (NAA) to determine the chemical composition of the clay component of the molding mass of archaeological ceramics to identify marker elements characteristic of various medieval ceramic production centers. 15 fragments of medieval vessels from the city of Bolgar, the capital of Volga Bulgaria (now the territory of Tatarstan) were provided for research by the Institute of Archeology of RAS. NAA was carried out by the NAA group of the IREN research facility at the Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research. Research has shown that all the studied ceramic samples had no significant differences either in the main components or in the traces. Also results were obtained, previously unknown to researchers of medieval ceramics.

The IREN complex for neutron physics research was constructed at the Frank Laboratory of Neutron Physics based on a linear accelerator of electrons up to an energy of 50 MeV. Measurements of the neutron flux density in a wide range of energies (from thermal to fast) are required in various experiments. This is done by neutron activation analysis with high-resolution gamma spectroscopy. In order to determine the flux of resonant neutrons more accurately, one needs to calculate the effective resonance integrals with specific features of the real neutron spectrum and the thermal motion and absorption of neutrons in the sample taken into account. A program for computation of effective resonance integrals has been developed for this purpose. The effective resonance integrals for 197 Au, 95 Zr, 97 Zr, and 63 Cu are calculated using this program. The values differ considerably from the ones given in reference literature. These results are used to more accurately determine the flux density of neutrons.

A neutron activation analysis (NAA) of three samples of human remains of the 16th and 17th centuries from the necropolises of the Moscow Kremlin has been carried out at FLNP JINR. The samples were irradiated at two facilities: the IREN source of resonance neutrons and the IBR-2 reactor. Spectra of the induced activity of the irradiated samples were measured by using the automatic measurement system developed at the Frank Laboratory of Neutron Physics (FLNP) of the Joint Institute for Nuclear Research (JINR). This system consists of a high-purity germanium detector with spectrometric electronics, a sample changer, and control software. Mass fraction of arsenic, mercury, and some other elements were calculated using two NAA methods—relative and absolute. The obtained values confirm the fact of acute mercury poisoning of Anastasia Romanovna, the first wife of Tsar Ivan Vasil’evich the Terrible, the first Russian Tsarina (died in 1560). High levels of mercury were detected in the bone remains of Tsarevich Ivan Ivanovich (died in 1581), the son of Tsar Ivan the Terrible, and Prince Mikhail Vasil’evich Skopin-Shuiskii (died in 1610). The results provide an opportunity to introduce into scientific circulation the exact values of mass fraction of mercury, arsenic, and other elements in the samples taken from the burials of the Russian historical figures of the second half of 16th–early 17th century.

Silicon carbide (SiC) and nitrogen-doped silicon carbide (SiC(N)) films were deposited on p-type Si(100) substrates at various deposition conditions by means of plasma enhanced chemical vapor deposition (PECVD) technology using silane (SiH4) methane (CH4) and ammonium (NH3) gas precursors. The concentration of elements in films was determined by RBS and ERD analytical method simultaneously. Chemical compositions were analyzed by FT-IR and Raman spectroscopy. The current-voltage (I-V) characteristics of structures before and after Xe ion and neutron irradiation were measured.

We performed an experimental search for the bound state singlet deuteron predicted in some microscopic calculations. The experiment consists in a high statistics measurement of gamma ray spectra after thermal neutron capture by hydrogen nuclei. The upper limit is obtained for the probability of the 3S1 - 1S0 -transition population of the deuteron singlet bound state with the bound energy in the interval 25-125 keV.

Amorphous silicon carbide (a-SiC) is an excellent alternative passivation layer material for silicon solar cells especially working in hard and space environment. Silicon carbide (SiC) and nitrogen-doped silicon carbide (SiC(N)) layers were deposited on P-type Si(1 0 0) substrates at various deposition conditions by means of plasma enhanced chemical vapor deposition (PECVD) technology using silane (SiH4) methane (CH4) and ammonium (NH3) gas as precursors. The concentration of elements in layers was determined by Rutherford backscattering spectrometry (RBS) and elastic recoil detection (ERD) analytical method simultaneously. Chemical compositions were analyzed by Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. Irradiation of samples by fast neutrons with fluence 1.4 x 10(14) cm(-2) was used. No significance effect on the IR spectra band features after neutron irradiation was observed. Intensity of Raman spectra band features was decreased after neutron irradiation. The measured currents after irradiation are greater (up to 100 times) than the current before irradiation for all samples. (C) 2012 Elsevier B. V. All rights reserved.

A prototype of a neutron spectrometer based on a gas proportional counter with recoil-proton registration is created at the Frank Laboratory of Neutron Physics at the Joint Institute for Nuclear Research (FLNP JINR) in Dubna. The spectrometer is developed to measure the kinetic energy of protons scattered elastically at small angles that are produced by (n, p) reaction in an environment containing hydrogen. The elaborated prototype consists of two cylindrical proportional counters used as cathodes. They are placed in a gas environment with a common centrally situated anode wire. Studies on the characteristics of the neutron spectrometer were conducted using 252Cf and 239Pu-Be radioisotope neutron sources. Measurements were made with monoenergetic neutrons produced by the 7Li(p, n)7Be reaction when a thin lithium target was bombarded with a proton beam from an EG-5 electrostatic accelerator, as well as with neutrons from the reaction D(d, n) 3He with a gas deuterium target.

Definition of the content of rare metals in the samples of ore was carried out by the method of the neutron activation analysis. IREN installation which represents the linear electron accelerator and no multiplying tungsten target served as the neutron source. The tungsten target has been located in the centre of the water moderator in diameter 15 cm [1].The irradiation has been spent on installation IREN within 8 hours 40 minutes. Electron energy was an order of 30 MeV, a current of an order 5 - 10 microamperes. Samples settled down on the moderator surface. 2 samples of ore have been irradiated: Os-1 (m = 1.172 g), and Os - 2 (m = 1.291 g) and a number of indicators for definition of neutron flux. Weights of indicators did not exceed a several milligrams.

Forthcoming experiments aimed at studying the mechanism of collinear cluster tripartition are planning to be performed with the new facility. Charged products will be registered with the double arm time‐of‐flight spectrometer composed of mosaics of PIN ‐diodes and MCP (micro channel plates) based timing detectors. Several tens of 3He‐filled counters will be gathered round the 252Cf source. In order to choose an optimal configuration of the neutron detector and other parameters of the experiment special modeling has performed using both “neutron barrel” and known MCNP code. The first test run of the new facility is in progress also its “neutron skin” in under construction.

Investigation of the 235 U( n th , f ) reaction using the miniFOBOS double-arm time-of-flight spectrometer of fission fragments confirmed manifestations of the earlier unknown many-body, at least ternary, decay involving almost collinear decay-product escape, which were first observed in the spontaneous fission of 252 Cf(sf). The use of variables sensitive to the nuclear charge of fission fragments allowed the reliability of identification of decay events to be increased and new decay modes to be revealed.

New experimental results on the ratio Rdp of the quasi-elastic charge-exchange yield at the outgoing proton angle \( \theta_{{p,{\rm Lab}}}^{}\) = 0° for the nd \( \rightarrow\) p(nn) reaction to the elastic np \( \rightarrow\) pn charge-exchange yield are presented. The measurements were carried out at the Nuclotron of the Veksler and Baldin Laboratory of High Energies of the JINR (Dubna) at the neutron beam kinetic energies of 0.55, 0.8, 1.0, 1.2, 1.4, 1.8 and 2.0GeV. The intense neutron beam with small momentum spread was produced by break-up of deuterons which were accelerated and extracted to the experimental hall. In both reactions mentioned above the outgoing protons with the momenta p p approximately equal to the neutron beam momentum p n, beam were detected in the directions close to the direction of incident neutrons, i.e. in the vicinity of the scattering angle \( \theta_{{p,{\rm Lab}}}^{}\) = 0° . Measured in the same data taking runs, the angular distributions of the charge-exchange reaction products were corrected for the well-known instrumental effects and averaged in the vicinity of the incident neutron beam direction. These corrected angular distributions for every of nd \( \rightarrow\) p(nn) and np \( \rightarrow\) pn charge-exchange processes were proportional to the differential cross-sections of the corresponding reactions. The data were accumulated by the Delta-Sigma set-up magnetic spectrometer with two sets of multiwire proportional chambers located upstream and downstream of the momentum analyzing magnet. Inelastic processes were considerably reduced by the additional detectors surrounding the hydrogen and deuterium targets. The time-of-flight system was applied to identify the detected particles. The new Rdp data are compared with the existing ones, which were obtained below 1GeV, and with the calculations which were made using the phenomenological NN amplitude sets.