Frank Laboratory of Neutron Physics is one of the laboratories of the Joint Institute for Nuclear Research that investigates the neutron as an elementary particle, and employs the neutron as an ...instrument to investigate the structure and dynamics of condensed matter, including crystals and nanosystems, functional materials, complex liquids and polymers, rocks, etc. so that our findings could find application in molecular biology and pharmacology, engineering diagnostics and in other fields of science and technology.
Major directions of the FLNP research program are: neutron-nuclear investigations, condensed matter physics and applied research.
The main objectives of the FLNP research in the framework of the condensed matter physics involved the application of neutron scattering techniques and complementary methods to investigate the structure, dynamics and microscopic properties of nanosystems and novel materials, modern condensed matter physics and interdisciplinary sciences.
In the field of neutron nuclear physics researches are carried out in investigations of time and space parity violation processes in neutron-nuclear interactions; studies of the fission process; experimental investigations of fundamental properties of the neutron; gamma-spectroscopy of neutron-nuclear interactions; nuclear data for reactor applications and nuclear astrophysics; experiments with ultracold neutrons.
The description of Dynamic Albedo of Neutrons (DAN) experiment is presented, as a part of the NASA’s Mars Science Laboratory mission onboard the mars rover Curiosity. The instrument DAN includes ...Pulsing Neutron Generator (PNG) producing pulses of 14.1 MeV neutrons for irradiation of subsurface material below the rover, and Detectors and Electronics (DE) unit, which operates the instrument itself and measures the die-away time profiles of epithermal and thermal neutrons following each neutron pulse. It is shown that the DAN investigation will measure a content of hydrogen along the path of the MSL rover, and it will also provide information about a depth distribution of hydrogen at 10–20 regions selected for the detailed studies and sampling analysis.
Data gathered with the Dynamic Albedo of Neutron (DAN) instrument onboard rover Curiosity were analyzed for variations in subsurface neutron flux and tested for possible correlation with local ...geological context. A special DAN observation campaign was executed, in which 18 adjacent DAN active measurements were acquired every 0.75–1.0 m to search for the variations of subsurface hydrogen content along a 15 m traverse across geologic contacts between the Sheepbed and Gillespie Lake members of the Yellowknife Bay formation. It was found that several subunits in Sheepbed and Gillespie Lake could be characterized with different depth distributions of water‐equivalent hydrogen (WEH) and different chlorine‐equivalent abundance responsible for the distribution of neutron absorption elements. The variations of the average WEH at the top 60 cm of the subsurface are estimated at up to 2–3%. Chlorine‐equivalent neutron absorption abundances ranged within 0.8–1.5%. The largest difference in WEH and chlorine‐equivalent neutron absorption distribution is found between Sheepbed and Gillespie Lake.
Key Points
DAN special campaign in Yellowknife Bay
DAN local measurements of water and chlorine abundance
Correlation of DAN measurements and geological context
The IBR-2 (JINR) pulsed reactor is used in the field of solid state physics for experiments on extracted beams. It is predicted that the IBR-2 reactor will reach resource limits in 2032–2037. To keep ...and develop beam research at JINR, the development of a new pulsed neutron source has begun. According to estimates, the reactor will have average thermal power 12–15 MW, extracted by sodium coolant. At this power, the average flux density of thermal neutrons on the surface of the water moderator will reach 10
14
sec
–1
·cm
–2
and the peak density 5·10
16
sec
–1
·cm
–2
, which is more than 10 times higher than the analogous parameters of the operating IBR-2 reactor. The new reactor is supposed to use neptunium-based fuel. The main characteristics and concept of the new reactor are presented.
The Dynamic Albedo of Neutrons (DAN) instrument on board Mars Science Laboratory has been operating successfully since the landing and has been making measurements regularly along Curiosity's ...traverse at the surface. DAN measures thermal (E < 0.4 eV) and epithermal neutrons (0.4 eV < E < ~1 keV) while operating in two different modes: active and passive. The active mode uses a pulsed neutron generator (PNG) to study the geological characteristics of the subsurface. In the passive mode, DAN measures the background neutron environment. This paper presents results of measurements in the passive mode from landing through to sol 100 and provides an interpretation of the data based on extensive Monte Carlo simulations. The main observations are summarized as follows: (1) the thermal neutron counts vary strongly along the rover traverse while the epithermal counts do not show much variation; (2) the neutrons from the Multi‐Mission Radioisotope Thermoelectric Generator (MMRTG) are a larger contributor to the DAN passive data than the Galactic Cosmic Ray (GCR)‐induced neutrons; (3) for the MMRTG neutrons, both the thermal and the epithermal counts increase as a function of the subsurface water content; (4) on the other hand, for the GCR‐induced neutrons, the thermal counts increase but the epithermal counts decrease as a function of the subsurface water content; and (5) relative contributions by the MMRTG and GCR to the DAN thermal neutron counts at the Rocknest site, where the rover was stationed from sol 59 to sol 100, are estimated to be ~60% and ~40%, respectively.
Key Points
The DAN passive mode measures the MMRTG neutrons and GCR‐induced neutrons
The thermal neutron counts show strong variability along the rover traverse
The majority of the DAN passive counts are from the MMRTG neutrons
—The Space Research Institute of the Russian Academy of Sciences (SRI RAS) and the Joint Institute for Nuclear Research (JINR) have been cooperating in nuclear planetology for 25 years. From the ...JINR, employees at the Laboratory of Neutron Physics and the Laboratory of Radiation Safety are involved in joint activities. During this time, a number of space instruments have been developed based on gamma and neutron spectroscopy, for which the JINR carried out detailed ground-based calibrations using various radiation sources and planetary soil models. Most of this scientific equipment is already operating on orbital and landing spacecraft and provide unique scientific data on the presence and distribution of water (ice) on the surface of the Moon and Mars and the elemental composition of the soil.
The design of the Lunar Exploration Neutron Detector (LEND) experiment is presented, which was optimized to address several of the primary measurement requirements of NASA’s Lunar Reconnaissance ...Orbiter (LRO): high spatial resolution hydrogen mapping of the Moon’s upper-most surface, identification of putative deposits of appreciable near-surface water ice in the Moon’s polar cold traps, and characterization of the human-relevant space radiation environment in lunar orbit. A comprehensive program of LEND instrument physical calibrations is discussed and the baseline scenario of LEND observations from the primary LRO lunar orbit is presented. LEND data products will be useful for determining the next stages of the emerging global lunar exploration program, and they will facilitate the study of the physics of hydrogen implantation and diffusion in the regolith, test the presence of water ice deposits in lunar cold polar traps, and investigate the role of neutrons within the radiation environment of the shallow lunar surface.
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The article presents results of ground calibrations of the FREND neutron telescope installed onboard the TGO spacecraft of the Russian-European ExoMars project. The main goal of the FREND space ...experiment is to measure hydrogen content in the subsurface layer of Mars to a depth of 1 m. High resolution maps of water mass fraction in the regolith are constructed based on these measurements. During ground physical calibrations, assessments of effective areas and measurements of angular sensitivity functions were obtained for each of the five FREND detectors. We demonstrate that FREND measurement characteristics correspond to its declared scientific goals and allow detecting and investigating local areas with enhanced water/water ice concertation on the subsurface of Mars with high spatial resolution of up to 60–200 km.
This article presents a description of the experiment on the Joint Institute for Nuclear Research (JINR) Phasotron proton beam for a laboratory model of a space instrument for the gamma spectrometry ...of celestial bodies based on the method of tagged charged particles of galactic cosmic rays. One feature of the experiment is the use of a p-type high-purity germanium semiconductor detector as part of the model.
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