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Today, almost everyone is faced with computer security problems in one or another way. Antivirus programs are used to control threats to the security of malicious software. Conventional methods for detecting malware are no longer effective enough; nowadays, neural networks and behavioral analysis technology have begun to be used for these purposes. Analyzing the behavior of programs is a difficult task, since there is no clear sequence of actions to accurately identify a program as malicious. In addition, such programs use measures to resist such detection, for example, noise masking the sequence of their work with meaningless actions. There is also the problem of uniquely identifying the class of malware due to the fact that malware can use similar methods, while being assigned to different classes. In this paper, it is proposed to use NLP methods, such as word embedding, and LDA in relation to the problems of analyzing malware API calls sequences in order to reveal the presence of semantic dependencies and assess the effectiveness of the application of these methods. The results obtained indicate the possibility of identifying the key features of malware behavior, which in the future will significantly improve the technology for detecting and identifying such programs.

Acetylene and ethylene are the smallest molecules that contain an unsaturated carbon–carbon bond and can be efficiently utilized in a large variety of cycloaddition reactions. In this review, we summarize the application of these C2 molecular units in cycloaddition chemistry and highlight their amazing synthetic opportunities.1 Introduction2 Fundamental Features and Differences of Cycloaddition Reactions Involving Acetylene and Ethylene3 (2+1) Cycloaddition4 [2+2] Cycloaddition5 (3+2) Cycloaddition6 [4+2] Cycloaddition7 (2+2+1) Cycloaddition8 [2+2+2] Cycloaddition9 The Use of Acetylene and Ethylene Cycloaddition for Deuterium and 13C Labeling10 Conclusions

A constraint $$g_{A}^{2}\leq 4.5\times10^{-24}\big(g^{2}+1/\lambda_{A}^{2}\big)$$ on the constant gA of a new short-range (spin—orbit) interaction between nucleons, which is due to the exchange by a light spin-1 boson with the mass mA = ħ/λAc, has been obtained from experimental data on the transmission of neutrons through a noncentrosymmetric perfect crystal near the Bragg reflection characterized by the reciprocal lattice vector g. This constraint is the best in the interaction radius range λA = 10−12−10−5 m.

The use of calcium carbide (in the presence of H2O) as a source of acetylene in the reaction with methyl 2-amino-4,6-O-benzylidene-2-deoxy-β-d-glucopyranoside under superbasic conditions (KF, KOH, DMSO, 130 °C, 3 h) led to the corresponding vinyl ether in 78% yield. The vinylation does not affect other reaction centers. Replacement of water with deuterium oxide in the reaction mixture gave a stable deuterated analog of this vinyl ether in 72% yield. The one-step isotopic enrichment was practically quantitative (isotopic purity >96%). Introduced deuterium atoms can be used as a convenient label in further transformations.

Among different types of labeling, 13C-labeled compounds are the most demanding in organic chemistry, life sciences and materials design. However, 13C-labeled organic molecules are very difficult to employ in practice due to extreme cost. The rather narrow range of labeled organic starting materials and the absence of universal synthetic building units further complicate the problem and make utilization of 13C-labeled molecules hardly possible in many cases. Here we report a versatile approach for 13C2-labeling of organic molecules starting with 13C elemental carbon: 13C carbon is applied for the synthesis of calcium carbide (Ca13C2), which is subsequently used to generate acetylene – a universal 13C2 unit for atom-economic organic transformations. Syntheses of labeled alkynes, O,S,N-functionalized vinyl derivatives, polymers and pharmaceutical substances were demonstrated. Elemental 13C carbon, as the chemically most simple source for 13C2-labeling, here was successfully combined with universal synthetic applicability of alkynes.

A test setup for measuring the neutron electric charge using spin interferometry and the effect of the double-crystal focusing of neutrons upon Laue diffraction is described. It is shown that a considerable increase in the distance between the crystals (up to 1 m) is needed to improve the accuracy of neutron-charge measurements. This is a difficult task because the setup becomes sensitive to slight external influences (temperature, vibration, etc.). To determine the degree of these influences, temperature tests with combined (active and passive) thermal protection were carried out. It is shown that under conditions of the reactor hall with temperature fluctuations of several degrees, the experimental setup provides a temperature stability of the crystals no worse than 0.01 K and stability of the temperature differences for the crystals and between them at a level of ~0.005 K. Measurements of the vibration level in the area of the PF1b cold neutron beam at the ILL reactor (Grenoble, France) allow estimation of the rate of displacement of crystals relative to each other at a level of ~10–3 cm/s. As follows from the data obtained, the angular resolution of the setup, without taking into account the influence of the imperfection of real crystals, can be at the level of 10–3 of the Bragg-reflection width, which is ~0.001 arc-second.

A method for protection of alcohols with vinyl groups is suggested and studied in detail. The procedures of protection and deprotection via vinylation and devinylation reactions are evaluated. Vinylation reaction is performed using cheap and convenient calcium carbide reagent. Stability of the vinyl group under various conditions is examined. The vinyl group is found to be stable under basic conditions and labile under acidic conditions. The vinyl protecting group shows high tolerance to functional groups and good compatibility with common synthetic reagents. Applicability of the procedure in the Suzuki and Sonogashira catalytic reactions and its flexible utilization in the reaction with Grignard reagent are demonstrated.

The spatial splitting of an unpolarized neutron beam into two spin components in an inhomogeneous magnetic field (an analog of the Stern-Gerlach experiment) with small gradients has been measured at the Laue diffraction in a crystal and Bragg angles θB = (78–82)° close to a right one. The spatial splitting of the beam at a path length of 21.8 cm has reached (4.1 ± 0.1) cm (at a maximum gradient of 1.5 G/cm and a diffraction angle of 82°). In the absence of the crystal, the splitting would be ∼ 3.8 × 10−7 cm at the same distance and gradient. The experimental enhancement coefficient is ∼ 105 tan2 θB, which is consistent with the theory.

A novel methodology for the preparation of trideuterovinyl derivatives of high purity directly from alcohols, thiols, and NH-compounds was developed. Commercially available calcium carbide and D2O acted as a D2-acetylene source, and DMSO-d 6 was used to complete the formation of the D2C=C(D)–X fragment (X = O, S, N). Polymerization of a selected trideuterovinylated compound showed a very promising potential of these substances in the synthesis of labeled polymeric materials. Biological activity of the synthesized trideuterovinyl derivatives was evaluated and the results indicated a significant increase of cytotoxicity upon deuteration.

The effect of neutron spin rotation at Laue diffraction in a weakly deformed neutron-transparent noncentrosymmetric crystal has been described theoretically and studied experimentally. The effect is due to the bending of a Kato trajectory of the neutron in the deformed crystal. At a certain type of deformation, one of two neutron waves excited at Laue diffraction, which propagate in opposite crystal fields in the crystal with no center of symmetry, leaves the crystal. As a result, the spin of the remaining neutron wave is rotated by a certain angle with respect to initial direction due to the interaction of the magnetic moment of a moving neutron with the crystalline electric field. This effect is absent in an undeformed perfect crystal, where only the depolarization of a beam occurs because both waves in opposite electric fields have the same amplitude. A method has been developed for controlled deforming the perfect single crystal by creating a temperature gradient in it. Thereby, a new possibility of measuring electric fields acting on a neutron in noncentrosymmetric crystals, as well as a method of controlling these fields in experiments on studying the fundamental properties of the neutron, has been implemented.

An impact of the finite size effects on the vacuum free energy density of full QCD with $N_{\rm f}$ massless flavors in the presence of homogeneous (anti-)self-dual Abelian background gluon field is studied. The zero temperature free energy density of the four-dimensional spherical domain is computed as a function of the background field strength $B$ and domain radius $R$. Calculation is performed in the one-loop approximation improved by accounting for mixing of the quark and gluon quasi-zero modes with normal modes, with the use of the $\zeta$-function regularization. It is indicated that, under plausible assumption on the character of the mixing, the quantum correction to the free energy density has a minimum as a function of $B$ and $R$. Within the mean field approach to QCD vacuum based on domain wall network representation of the mean field, an existence of the minimum may prevent infinite growth of individual domain, thus protecting the vacuum from the long-range ordering, and, hence, serving as the origin of disorder in the statistical ensemble of domain wall networks, driven by the minimization of the overall free energy of the dominant gauge field configurations., Comment: 31 pages, 12 figures

A prototype system design for ultra-high-precision neutron spectrometry using diffraction in perfect crystals is described. Results of experimental verification of the temperature stability inside the setup are presented. Results of vibration spectrum measurements in working zone of the PF1b beam of ILL reactor (Grenoble, France), where the prototype setup will be arranged for experimental testing, are considered.

A new mechanism of neutron acceleration in the accelerated perfect crystal is proposed and studied experimentally. The effect arises due to the resonance energy dependence of the neutron refraction index in vicinity of the Bragg's energy. During the neutron time-of-flight through the accelerated crystal the relative neutron-crystal velocity will be changing (with the deviation from the exact Bragg condition) and so the refraction index and the velocity of outgoing neutron will change as well.

The currently known methods for the preparation of vinyl ethers, vinyl sulfides and enamines are analyzed and described systematically. The published data on the reactions of alcohols, thiols and various nitrogen-containing compounds with acetylene, resulting in the corresponding vinyl derivatives, are considered. The attention is focused on the application of convenient acetylene sources. Other modern approaches to the synthesis of vinyl derivatives are described in detail, including vinyl exchange and metathesis reactions, various types of cross-coupling and cleavage of organic compounds. Some specific synthetic routes to vinyl ethers, vinyl sulfides and enamines are presented in the last Section. The bibliography includes 262 references.

The effect of neutron spin rotation at Laue diffraction in a noncentrosymmetric weakly deformed neutron-transparent crystal has been studied experimentally. The effect appears because of two phenomena: (i) the interaction of the magnetic moment of a moving neutron with the crystalline electric field and (ii) bending of trajectories of the neutron in a deformed crystal; as a result, the amplitudes of two waves excited at Laue diffraction, which propagate in the crystal in opposite electric fields, at the output of the crystal are not equal.

Investigations of the spatial resolution of a setup for verification of the equivalence of inertial and gravitational masses of a neutron by the method of diffraction in a perfect crystal have been performed. Tests were conducted at Bragg angles of 74°–82°. A decrease in spatial resolution at Bragg angles >78° is detected.

A new mechanism of neutron acceleration is studied experimentally in detail for cold neutrons passing through the accelerated perfect crystal with the energies close to the Bragg one. The effect arises due to the following reason. The crystal refraction index (neutron–crystal interaction potential) for neutron in the vicinity of the Bragg resonance sharply depends on the parameter of deviation from the exact Bragg condition, i.e. on the crystal–neutron relative velocity. Therefore the neutrons enter into the accelerated crystal with one neutron–crystal interaction potential and exit with the other. Neutron kinetic energy cannot vary inside the crystal due to its homogeneity. So, after passage through such a crystal, neutrons will be accelerated or decelerated because of the different energy change at the entrance and exit crystal boundaries.

The sensitivity of the method of neutron scattering to novel neutron–nucleon interactions is analyzed. Upper limits on the coupling constant of such interactions are imposed using the available data on neutron powder diffraction on polycrystalline silicon. For the forces acting at ranges of λ < 10–11 m, these upper limits are already competitive with the best existing constraints on their coupling constant. A dedicated experiment can help improve the sensitivity to this coupling constant by nearly two orders of magnitude.

Review of the new crystal-diffraction methods to study fundamental neutron properties and interactions is presented. Features of neutron optics in the crystal without a center of symmetry is discussed as well as the first experimental results and perspectives to improve the sensitivity of experiments on a search for the neutron electric dipole moment (EDM) and CP-violating short-range pseudomagnetic nucleon-nucleon interaction. Also, the possibility to develop ultra-precise neutron spectroscopy using Laue diffraction in the perfect crystal is discussed, which can be used for a broad range of experiments: search for the neutron electric charge; test of the equivalence principle; precise measurements of neutron scattering amplitudes; crystal quality testing.

Recent progress in the leading synthetic applications of acetylene is discussed from the prospect of rapid development and novel opportunities. A diversity of reactions involving the acetylene molecule to carry out vinylation processes, cross-coupling reactions, synthesis of substituted alkynes, preparation of heterocycles and the construction of a number of functionalized molecules with different levels of molecular complexity were recently studied. Of particular importance is the utilization of acetylene in the synthesis of pharmaceutical substances and drugs. The increasing interest in acetylene and its involvement in organic transformations highlights a fascinating renaissance of this simplest alkyne molecule.

A novel synthetic methodology for the preparation of 1,3-disubstituted pyrazoles from in situ generated nitrile imines and acetylene is reported. The reactions are performed in a simple two-chamber reactor. One part of the reactor is loaded with hydrazonoyl chloride precursors of active nitrile imine species and a base. The other part is used to generate acetylene from CaC2 and water. Partitioning of the reactants improves the yields of desired pyrazoles up to 99% and simplifies their isolation to a simple procedure of solvent evaporation. The approach requires no complex equipment and utilizes inexpensive, safe, and easy to handle calcium carbide as a starting material. A model deuterium incorporation is carried out according to the developed methodology, producing a series of novel 4,5-dideuteropyrazoles with excellent deuterium enrichment. Theoretical calculations on reaction mechanism and characterization of possible intermediate structures were performed.

The effect of two-crystal focusing of neutrons at Laue diffraction from large perfect silicon crystals has been studied. It has been shown that the focusing effect makes it possible to reach an angular resolution better than 0.03″, which is about 0.01 of the width of a Bragg reflection. This circumstance allows a new ultraprecision neutron-spectrometry method based on the method of spin-echo small-angle neutron scattering in combination with Laue diffraction.

The magnetization curves of magnetically aligned finely powdered samples of the (TmxPr1-x)2Fe17 compounds have been measured at 4 K. The easy magnetization axis is oriented in the basal plane or along the hexagonal axis for the compounds with x = 0-0.3 and 0.7-1, respectively. This is because of the absence of magnetic ordering in the Tm and Pr subsystems in these ranges, respectively, and because of competing anisotropy of the subsystems. For the compositions with x = 0.4-0.6, both rare-earth subsystems are magnetically ordered and the easy magnetization axis is oriented between the basal plane and the hexagonal axis. The critical fields of FOMPs decrease quickly as the Pr or Tm content decreases in the ranges 0-0.3 and 0.7-1, respectively. The magnetization anisotropy also diminishes as the Tm content becomes smaller than x = 0.7. No influence of the intrinsic microdeformations on the magnetization of the compounds was detected.

We measured the spatial splitting of a non-polarized neutron beam passed through a crystal under diffraction conditions in heterogeneous magnetic field (analog to the Stern-Gerlach effect) into two polarized components with opposite polarization. The measurements were carried out using Laue diffraction scheme, small gradients of the magnetic field and Bragg angles close to orthogonality θB=(78−82)∘. After a flight path in crystal of 21.6 cm a splitting of 4.1±0.1 cm was achieved (using a field gradient of ∼3 G/cm and a diffraction angle of 82∘). In the absence of a diffraction (crystal) but otherwise the same flight path and field gradient the spatial splitting would be ∼4⋅10−7 cm. From those we deduce an experimental amplification factor in the order of about ∼2⋅105tan2⁡θB due to the use of diffraction in crystals, which agrees with theory.

Crystal structure and magnetic and thermomagnetic properties of the Pr2Fe17-x M x compounds with M = Ti, V, Cr, Zr, Nb have been studied. The change of interatomic distances is not enough to explain the growth of the Curie point and it is necessary to assume the distribution of M = Ti, V, Cr, Nb atoms over the lattice positions, similar to that previously published for the Nd2Fe17-x M x compounds. It was established by neutron diffraction that Zr atoms substitute for Pr atoms in the 6c site and do not substitute for Fe atoms as might be expected from the original formula Pr2Fe16.5Zr0.5. So, the real composition of the substituted compound studied is Pr14.8(8)Zr0.52(8)Fe17. The magnetic moment of Fe atom and the magnetocaloric effect in the Pr2Fe17-x M x compounds decrease with decreasing Fe content.

We describe the structure design and present the results of experimental testing of a birefringent magnetic neutron prisms for spin-echo small-angle neutron scattering (SESANS). The SESANS setup, equipped with perfect single crystals for measuring diffraction-enhanced spin interference effects, must possess unprecedented sensitivity with respect to small external actions on a neutron and is intended for use in experiments for checking the neutron electroneutrality.

We propose a novel experiment to test the weak equivalence principle (WEP) for the Laue diffracting neutron. Our experiment is based on an essential magnification of an external affect on neutron diffracting by Laue for the Bragg angles close to the right one in couple with additional enhancement factor which exists due to the delay of the Laue diffracting neutron at such Bragg angles. This enhancement phenomena is proposed to be utilized for measuring the force which deviates from zero if WEP is violated. The accuracy of measuring inertial to gravitational neutron masses ratio for the introduced setup can reach ∼10−5, which is more than one order superior to the best present-day result.

Thermolysis of alk-1-enyl-N-phthalimidoaziridines leads to products of 1,5-electrocyclization of intermediate azomethine ylides with participation of C=C bonds. If acyl or alkoxycarbonyl substituent is present in the aziridine ring, the C=O bond is also involved. Thermolysis of the title compounds in the presence of N-phenylmaleimide or dimethyl acetylenedicarboxylate under analogous conditions gives products of 1,3-dipolar cycloaddition of azomethine ylides to the double or triple bond of the dipolarophile.

A direct experimental observation of the anomalous absorption of neutrons undergoing Laue diffraction in a highly perfect silicon single crystal of size about 200 mm at Bragg angles close to π/2 is reported. It is shown that, in the case of diffraction at the (220) plane, the neutron absorption length may be several meters, which is nearly one order of magnitude longer than the mean absorption length for neutrons of the same wavelength. This circumstance makes it possible to study effects accompanying Laue diffraction at Bragg angles of up to 88° and a crystal size of about 200 mm.

The intramolecular thermal cycloaddition of N-phthalimidoaziridines at multiple bonds of substituents with the intermediate formation of azomethine ylides leads to condensed pyrrole derivatives, in which the five-membered ring is adjacent to a five-, six-, or seven-membered ring. Rearrangements, which sometimes become the predominant reactions, compete with cycloaddition. Thus, aziridines with aryl substituents readily isomerize to give imines with a 1,2-shift of the phthalimide group to one of the carbon atoms. Aziridines with one electron-withdrawing substituent probably do not open to give 1,3-dipoles but rather undergo a Cope-type rearrangement involving the three-membered ring and C = O bond of the second substituent. Even in intramolecular reactions, very low activity is found for the cyano group triple bond and aromatic ring bonds as dipolarophiles.

Heating 2-acyl- and 2-alkoxycarbonyl-N-phthalimidoaziridines leads to substituted oxazoles in 45-65% yield. Only esters of oxazolecarboxylic acids are formed when the aziridine contains acyl and alkoxy groups. The thermolysis of the same aziridines in the presence of N-phenylmaleimide and the dimethyl ester of acetylenedicarboxylic acid gives both oxazoles and the products of 1,3-dipolar cycloaddition from aziridines with two substituents at the carbon atoms but only oxazoles from trisubstituted aziridines.

The effect of the neutron spin rotation at Laue diffraction in a weakly deformed noncentrosymmetric and transparent for the neutrons crystal has been theoretically described and experimentally investigated. This effect arises in the deformed crystal because of the curvature of the neutron trajectory in the crystal. A certain type of deformation leads to the escape outside the crystal of one of the two neutron waves excited at Laue diffraction. This two waves propagate in the crystal without a center of symmetry in electric fields with the opposite sign. In this case the spin of the remaining neutron wave will be rotating relative to the original direction due to the interaction of the magnetic moment of the moving neutron with the crystal's intracrystalline electric field. In a perfect undeformed crystal such spin rotation effect is absent. There is only a depolarization of the beam since both waves in opposite electric fields are present with the same amplitudes. A technique for controlled deformation of a perfect single crystal by creating a temperature gradient has been developed. Thus a new possibility to measure the electric fields which act on the neutron in noncentrosymmetric crystals has been realized. There also appeared a way to control these fields in experiments on the study of the neutron fundamental properties.

A crystal-di_raction experiment is discussed to test weak equivalence principle for neutrons. The idea of the experiment is based on essential magnification of any external force, acting on a neutron under di_raction at the Bragg angles close to the π/2 for Laue di_raction case. The enhancement factor from di_raction for neutron trajectory “curvature” in the crystal due to an external field can reach magnitudes of about ∼ (10 8 - 10 9 ) in comparison with a “free” neutron in the same field. Hence, the accuracy to measure the ratio of inertial to gravitational neutron masses can reach ∼ 10 -5 , that is about one order higher than best result.

An experiment using a prototype setup to search for the neutron electric dipole moment by measuring spin-rotation in a non-centrosymmetric crystal (quartz) was carried out to investigate statistical sensitivity and systematic effects of the method. It has been demonstrated that the concept of the method works. The preliminary result of the experiment is $d_{\rm n}=(2.5\pm 6.5)\cdot 10^{-24}$ e$\cdot $cm. The experiment showed that an accuracy of $\sim 2.5\cdot 10^{-26}$ e$\cdot $cm can be obtained in 100 days data taking, using available quartz crystals and neutron beams., 13 pages, 4 figures

Thermolysis of 3-(2-allyloxyphenyl)- or 3-(2-propargyloxyphenyl)-1-phthalimidoaziridine-2-carboxylic acid derivatives results in stereospecific intramolecular cycloaddition of intermediate N-phthalimidoazomethine ylides to double or triple carbon–carbon bonds. This leads to condensed N-phthalimidopyrrolidines, N-phthalimidopyrrolines, or products of their subsequent transformations. On the other hand, thermolysis of similar dimethyl 3-aryl-1-phthalimidoaziridine-2,2-dicarboxylates gives exclusively 5-methoxyoxazoles, the products of a competitive 1,5-dipolar electrocyclization.

The essential magnification of an external affect on neutron diffracting by Laue for the Bragg angles θ B close to right one has been experimentally observed. The factor of diffraction enhancement for the neutron trajectory “curvature” due to external field is proportional to tan 2 θ B and can reach magnitude ∼ 10 8 – 10 9 in comparison with a free neutron. The new method to measure a neutron electric charge and the ratio of inertial to gravitational masses has been proposed. The estimations have shown a feasibility to improve the accuracy of a neutron electric charge measurement by about two orders of magnitude in comparison with the current value and measure the ratio of inertial to gravitational masses with the accuracy about σ ( m i / m G ) ∼ 10 - 6 .

Detailed study of a neutron Laue diffraction in a noncentrosymmetric crystal was carried out using a prototype of the experimental setup to measure the neutron electric dipole moment (nEDM) by Laue diffraction method (LDM). A new kind of spin rotation effect was observed for the first time. We attribute this effect to a difference of the two Bloch waves amplitudes in the crystal, which is caused by the presence of the definite small crystal deformation. In a revised scheme of the experiment, this effect could be exploited for a purposeful manipulation of the Bloch waves.

An essential magnification of an external force acting on a diffracting neutron for the Bragg angles θB close to the right one is observed. Any external action (caused by either crystal deformation or external force affected the neutron) results in a bend of the so called “Kato trajectories” inside the crystal and, for the case of a finite crystal, gives considerable variation of the intensities of both diffracted neutron beams (direct and reflected). It is shown that the magnification factor is proportional to tan2 (θb) and can reach (102−103) for Bragg angles surfficiently close to 90°.

A new way is proposed and investigated for observing and fine tuning a neutron spin rotation effect caused by the Schwinger interaction of the moving neutron with the strong interplanar electric field of the noncentrosymmetric quartz crystal. By that we have got an opportunity to control the electric field acting on neutron. The value and sign of this field depend on the deviation of a neutron energy from the Bragg one. We used a second crystal parallel to the main one for selection of the neutrons with the given deviation parameter. The possibility to control the electric field acting on the registered neutrons has been realized by heating (or cooling) the second crystal. Observed effects give a real prospects to improve essentially the scheme and sensitivity of the experiment for a search for neutron electric dipole moment (EDM) using the crystal diffraction technique.

The feasibility of an experiment to search for the neutron electric dipole moment (EDM) by Laue diffraction in crystals without a center of symmetry was tested. At the PF1A beam of the ILL reactor a record time delay of τ ≈2 ms for the passage of neutrons through a quartz crystal was reached for the (1 1 0) plane and diffraction angles equal to 88.5°. That corresponds to an effective neutron velocity in the crystal of 20 m/s, while the velocity of the incident neutron was 800 m/s. It was shown experimentally that the value τN 1/2 , determining the method's sensitivity, has a maximum for the Bragg angle equal to 86°. The results allow us to estimate the statistical sensitivity of the method for the neutron EDM. For the PF1B beam of the ILL reactor the sensitivity can reach ∼6×10 −25 e cm per day for the available quartz crystal.

First observation of new effects was carried out using the set-up created for searching for a neutron electric dipole moment (EDM) by a crystal-diffraction method. For the first time the neutron dynamical Laue diffraction for the Bragg angles close to a right angle (up to 87°) was studied, using the direct diffraction beam and a thick (∼3.5-cm) crystal. The effect of an essential time delay of diffracting neutrons inside the crystal for Bragg angles close to 90° was experimentally observed, using a time-of-flight method. The phenomenon of neutron-beam depolarization was first experimentally observed for the case of Laue diffraction in a noncentrosymmetric α-quartz crystal. It is experimentally proved that the interplanar electric field, affecting a neutron in a crystal, maintains its value up to Bragg angles equal to 87°. These results confirm the opportunity to increase by more than an order of magnitude the sensitivity of the method to the neutron EDM, using the diffraction angles close to 90°, and give a real prospect to exceed the sensitivity of the magnetic resonance method, using ultra-cold neutrons.

Possible future progress of the crystal-diffraction neutron electric dipole moment search experiment is discussed. A storage modification of the experiment is proposed. It is demonstrated that sensitivity of the method can be a few 10 −27 e cm for the BSO crystal with the size 10×10×10 cm 3 and expected luminosity of European Spallation Source (ESS).

Rotation of the spin of cold neutrons passing through a noncentrosymmetric single crystal is observed. This effect is caused by the Schwinger interaction of the magnetic moment of a moving neutron with the crystalline electric field in a noncentrosymmetric single crystal and depends both on the direction of neutron trajectory in the crystal and on its energy. It is shown that the characteristic magnitude of the effect for α-quartz is ≃(1–2)×10−4 rad/cm over a wide wavelength range (from 2.8 to 5.5 A) and is determined by the degree of beam monochromaticity [Δλ/λ=(2–5)×10−2 in our experiment]. This magnitude corresponds to an electric field of ≃(0.5–1)×105 V/cm acting on a neutron. The measured value agrees well with the theoretical calculation.

An experiment searching for the neutron electric dipole moment by measuring spin-rotations in a non-centrosymmetric crystal was carried out to investigate the statistical sensitivity and systematic effects of the method. The preliminary result of this experiment is d n = ( 2.5 ± 6.5 ) ⋅ 10 − 24 e ⋅ cm . The performance was essentially limited by the low luminosity of the prototype setup. With a dedicated setup and a large quartz crystal, the expected accuracy is ∼ 2 ⋅ 10 − 26 e ⋅ cm for 100 days of data collection.

A simple method for the relative measurement of the interplanar distances of high perfect crystals with a high precision is described. It is based on the comparison of the interplanar distances of two crystals using neutron transmission through one crystal and back reflection by the reference second crystal at Bragg angles close to 90 ∘ . The method allows us to measure the variation of the crystal interplanar distance Δ d relatively to the reference with the accuracy Δ d / d better than 10 - 7 .