Pulsed neutron generator
SUBSTANCE: in the pulsed neutron generator comprising a neutron tube, a storage capacitor and a high voltage transformer with the multilayer secondary winding and interlayer insulation, arranged coaxially in the sealed body flooded with liquid dielectric, projecting beyond the rows, formed on the frame, and an additional coil parallel to the secondary transformer winding, wound with the wire of high resistivity and high magnetic permeability, neutron tube is provided with an additional controlled three-electrode ion source, the target electrode is placed in the middle of the neutron tube body and has two symmetrical targets saturated with single or different hydrogen isotope, the secondary transformer winding and the additional winding are formed as two symmetrical truncated cones having a common small base, wherein the end turns of the windings located on the small base, are connected to the target electrode, while the end windings located on the large grounds, are connected to the neutron generator body.
EFFECT: enhancing functional and performing features of the neutron generator.
SUBSTANCE: proposed generator consists of pulsed HV voltage source and vacuum chamber including anode and cathode. Anode is composed of a hollow toroidal azimuthal-symmetric structure of two ring-shape plates with outer radius R and inner radius r spaced apart by distance l. At least n pulse heavy hydrogen isotope ion sources are arranged there between where n is not smaller than 3, source height and width being h and f. Cathode is arranged inside anode and aligned therewith and consists of two cylindrical d-diameter magnetic elements arranged in symmetry about anode and space by distance L with lengthwise magnetization to induction of 0.3 < B < 0.6 Tl. Outlets of heavy hydrogen isotope ion sources are directed toward anode axis while sizes R, r, l, L, h, f, d satisfy the preset ratios.
EFFECT: longer life owing to longer life of neutron-forming target.
SUBSTANCE: in sealed neutron tube between body of ion source and anode there is a tubular insulator installed in parallel to the tube axis along the whole lengths except for ends; the insulator is covered with conducting layer coupled electrically to cathode and inside the tubular insulator there is wire conductor coupled to extraction electrode and output of bushing insulator.
EFFECT: increasing efficiency of ion source of the sealed neutron tube and increasing neutron flux.
SUBSTANCE: generator includes a grid having the possibility of ionised gas generation at heating with electrons colliding with it. A cathode emits electrons for heating of the grid and collisions with generated ionised gas atoms for formation of ions. Neutrons are formed as a result of collision of ions falling down to a target in the generator. A tool for underground use, which includes a neutron generator, is described.
EFFECT: improving reliable operation and reducing labour intensity for manufacture; providing the possibility of operation with different types of sources and under different conditions.
25 cl, 5 dwg
SUBSTANCE: generation method of pulse flux of high-energy particles involves the following stages: initiation of ion plasma on the first electrode (111) in vacuum chamber (110) and provision of possibility of developing the above plasma in the direction to the second electrode (112) in the above vacuum chamber, supply of short high-voltage pulse between the above electrodes at time interval, at which the above ion plasma is in transient state with spatial distribution of ions or electrons at the distance from the above second electrode, for the purpose of accelerating the above distributed ions or electrons in direction to the above second electrode, due to which high-energy flux of charged particles is generated; at the same time, current limit is overcome, which is related to spatial charge, of common vacuum diode, and generation of the above high-energy particles on the above second electrode (112).
EFFECT: increasing current density during ultrashort pulse.
11 cl, 6 dwg
SUBSTANCE: device includes a source of ions placed under pressure in the medium containing an ionisable gas. The source of ions includes substrate with a bundle of carbon nanotubes passing away from it. Ends of nanotubes are spaced apart with a grate. Voltage supply electronic circuit provides gas ionisation and ion emission through the grate. Ion accelerator section is located between the source of ions and the target. Ion accelerator section accelerates ions passing through the grate to the target, so ion-target collision stipulates generation and emission of neutrons from it. The source of ions, accelerator section and target are placed in a sealed tube and carbon nanotubes in a bundle should be perfectly ordered preferably with at least 106 of carbon nanotubes per cm2 passing in direction parallel in essence to the central axial line of the tube.
EFFECT: creating gas ionisation with high atom-molecule ratio thus ensuring creation of compact small-sized samples suitable for logging tools.
16 cl, 2 dwg
FIELD: machine building.
SUBSTANCE: control over ball motion is effected thanks to the fact that there is difference in gas static pressure ahead of and behind the ball moving in gas flow. Orifices in diameter not exceeding 1/3 of ball diameter are made in tube wall. Gas pressure is transmitted via thin tubes to sensitive differential diaphragm pressure gage. Origination of dynamic signal testifies about ball position in tube length between gas bleed orifices. Proposed method consists in that said ball is registered by short negative pulse of differential pressure developing in the ball "gas shadow", that is immediately behind the ball, right at approach to the first gas bleed point.
EFFECT: control over ball motion in whatever conditions.
3 cl, 2 dwg
SUBSTANCE: gas-filled neutron tube with a Penning source arranged in the form of a tight flask. In the flask there is a target, an ion-optic system, a source of ions and a working gas generator. On the inner surface of the tight flask in the zone of electrodes of the ion-optic system there is a notch that increases area of the inner surface of the tight flask. The notch may be arranged with sinusoidal shape, amplitude and period of 1 mm.
EFFECT: improved reliability and resource of neutron tube operation.
3 cl, 2 dwg
SUBSTANCE: gas-filled neutron source with a Penning ion source with a thermionic cathode is made in form of an airtight metal-glass bottle. Inside the bottle there is a target, ion-optical system, ion source, working gas generator and gas absorbent. The gas absorbent is placed on one of the inlets of the legs of the gas-filled neutron tube, has a built-in thermo-heater and is made in form of a bushing from sintered fine-grained titanium powder with mass ranging from 100 to 350 mg.
EFFECT: invention allows for increasing electric strength of the ion-optical system of the tube with a Pennning ion source and a thermionic cathode, as well as increasing neutron current and service life.
1 cl, 1 dwg
SUBSTANCE: invention relates to sealed neutron tubes and can be used in neutron generators for research of geophysical and field wells. Sealed neutron tube features axial grooves in tube high voltage insulator on the part of end faces perpendicular to insulator axis; ion source and accelerating electrode are installed at collar flanges. Outer diametre of the central flange part is equal to groove diametre and collar diametre is bigger than groove diametre but less inner diametre of cup; central flange part is installed tightly in grooves and collar of the flange is pressed against insulator end faces.
EFFECT: increase of neutron yield, reduction of relative shift of ion source and accelerating electrode, reduction of beam axial deviation.
FIELD: electrical engineering.
SUBSTANCE: proposed device relates to neutron generators and can be used in neutron logging, in neutron activation analysis, and in beam-therapy. The neutron generator has a radiation source-detector pair. The radiation source-detector pair is located in the line-of-sight of each other. One radiation source-detector is put in a grounded case and is electrically connected to a device for controlling the ion source, which is at zero potential. The other radiation source-detector is in a container and is connected to the power supply of the ion source, fitted in the container. The radiation source-detector pair is separated by a high-voltage insulation layer.
EFFECT: reduced size of neutron generator.
FIELD: physics, geophysics.
SUBSTANCE: invention relates to nuclear geophysics and is used for estimation of cement stone density of buried gas storages in their operation without lifting of oil-well tubing. Claimed method comprises measurement of current magnitudes A as Ca/Si ratio in wells by devices of wide-band spectrometric neutron gamma-logging, selection of Amin and Amax of Ca/Si) ratio, and determination of double difference parameter from measurement results (DDP(Ca/Si)) by formula
EFFECT: higher accuracy of data.
FIELD: oil and gas industry.
SUBSTANCE: rocks are irradiated by pulses of a fast neutron generator, inelastic gamma ray spectrometry (IGRS) for neutrons and http://alk.pp.ru:8080/c/m.exe?t=4301645_1_2 The device for pulsed neutron logging is also claimed, and the device comprises a fast neutron generator placed in a protective casing, a scintillation gamma-ray detector coupled optically to a photomultiplier tube, a screen between the fast neutron generator and scintillation gamma-ray detector, an analogue-code converter, the central processing unit, a receiver-transmitter unit, the first and second memory units, a high-voltage software-programmable unit characterised by equipment with an auxiliary time-mode control unit for the fast neutron generator.
EFFECT: improvement of accuracy during pulsed neutron logging.
2 cl, 7 dwg
SUBSTANCE: application: to define density of subsurface formations. The essence of the invention consists in the fact the density of a subsurface formation surrounding a bore well is defined on the basis of measuring the gamma rays resulting from the formation's exposure to the radiation from a nuclear source in the device casing which is set in the bore well, and the gamma ray flux is measured in the device casing at two different distances of detectors from the source; the method provides the definition of, in essence, straight-line relationship between the measurements of gamma ray fluxes at each different distance of detectors in terms of the formation density in case of no deviation of the device casing; definition of the relationship setting the density deviation caused by the device deviation and defined on the basis of the measurements of measured gamma ray flux at two different distances of detectors in terms of the density calculated on the basis of the straight-line relationships, and for this pair of measurements of gamma ray flux at different distances of detectors, a definition of intersection of the relationship, setting the deviation, with the straight-line relationship in order to specify the density of the formation surrounding the bore well. The source is a neutron source and the gamma rays measured in the device casing are the gamma rays induced by the neutrons and resulting from the neutron irradiation of the formation.
EFFECT: improved accuracy at the definition of subsurface formation density.
25 cl, 5 dwg
SUBSTANCE: system, method and device are represented for determining the values of porosity of a subsurface layer, adjusted taking into account the well influence. The well tool is lowered into the well of the subsurface layer comprises a source of neutrons, two or more neutron detectors and a data processing scheme. The source of neutrons emits neutrons into the subsurface layer. Two or more neutron detectors are arranged in two or more azimuthal orientations in the well tool and detect the neutrons scattered by the subsurface layer or the well fluid in the well, or both of them. Based on the neutrons detected by the neutron detectors, the electronic data processing scheme determines the value of porosity of the subsurface layer adjusted taking into account the influence of the well.
EFFECT: improvement of accuracy of the measurements.
29 cl, 37 dwg
FIELD: oil and gas industry.
SUBSTANCE: logging device is moved along the borehole, a repetitively-pulsed fast neutron flux is generated in the well, a time analysis of the thermal neutrons flux rate is carried out for each quantum of the formation depth, values of baseline decrements are determined for the drop in the thermal neutrons flux rate. A chemical solution containing compounds with anomalously high macro cross-section of nonfission neutron absorption is pumped into the well under pressure, then values of baseline decrements are determined for the drop in the thermal neutrons flux rate repeatedly, ultrasonic radiation is generated in the well and the formation is impacted by this radiation, thereafter values of baseline decrements are determined for the drop in the thermal neutrons flux rate for satisfaction of the respective system of inequalities containing values of decrements obtained at all three stages of measurements. Against satisfaction of these inequalities a judgement is made about potential maintenance of the well flow rate at the operational level with periodical impact on the formation by a longitudinal acoustic pressure wave.
EFFECT: possible identification of productive formations where usage of acoustic impact on the formation to maintain the well flow rate gives positive result.
FIELD: measurement equipment.
SUBSTANCE: neutron downhole device for determination of porosity includes a source of neutrons, a device of neutron control, a neutron detector and a circuit of data processing. The source of neutrons may emit neutrons into an underground bed, and the neutron control device determines count of neutrons proportionate to emitted neutrons. The neutron detector may determine the count of neutrons, which are scattered from the underground bed. The data processing circuit may determine porosity of the underground bed corrected by impact of environment on the basis of at least partially count of neutrons scattered from the underground bed normalised to the count of neutrons proportionate to neutrons emitted by the source of neutrons.
EFFECT: provision of possibility of neutron geophysical research of porosity with high accuracy and reduced lithological effects.
12 cl, 16 dwg
SUBSTANCE: method of determining water saturation in a subsurface formation involves determining an invasion depth in the formation from a plurality of measurements made within a wellbore drilled through the formation. The measurements have different lateral depths of investigation in the formation. Carbon and oxygen in the formation are measured at substantially the same longitudinal position as the position of determining the invasion depth. The measured carbon and oxygen and the invasion depth are used to determine water saturation in a substantially uninvaded part of the formation.
EFFECT: high accuracy of data on saturation of formations with fluids.
19 cl, 4 dwg
FIELD: oil and gas industry.
SUBSTANCE: measurements are made by means of a pulsed neutron logging method (PNL) and calculation of macroscopic absorption section of mine rock thermal neutrons is performed; macrocomponent rock composition is determined for geophysical well logging complex (GWL), including porosity; with that, for calculation of macroscopic absorption section of thermal neutrons with formation water and hydrocarbons there used are their elemental composition and density, and calculation of hydrocarbon saturation itself is performed as per certain relationship; with that, for calculation of macroscopic absorption sections of thermal neutrons with macrocomponents forming solid phase of rocks there additionally prepared is a collection of core sample from test wells, on which there performed are measurements of mineral, elemental composition of samples and losses of sample weight at heating; mineral component model of rock is formed and macroscopic absorption sections of thermal neutrons are calculated for each macrocomponent forming a solid rock phase.
EFFECT: improving accuracy of determining hydrocarbon content.
SUBSTANCE: downhole tool has a neutron source configured to emit neutrons according to a pulse formation scheme, the pulse formation scheme comprising a delay between two pulses, the delay being sufficient for all neutron capture events caused by emitted neutrons to substantially stop, and the delay is longer than or equal to about 1 s; a gamma-radiation detector configured to detect activation gamma-radiation generated when neutron radiation activated elements decay to a non-radioactive state.
EFFECT: enabling determination of a formation element using only activation gamma-radiation from activated formation nuclei.
23 cl, 10 dwg
SUBSTANCE: neutron capture gamma-ray spectroscopy system includes: a downhole tool, having: a neutron source configured to emit neutrons into a subterranean formation to cause inelastic scattering events and neutron capture events; a neutron monitor configured to detect a count rate of the emitted neutrons; and a gamma-ray detector configured to obtain gamma-ray spectra derived at least in part from inelastic gamma-rays produced by the inelastic scattering events and neutron capture gamma-rays produced by the neutron capture events; and data processing circuitry configured to determine a relative elemental yield from the gamma-ray spectra and to determine an absolute elemental yield based at least in part on a normalisation of the relative elemental yield to the count rate of the emitted neutrons.
EFFECT: enabling determination of accurate elemental concentration in neutron capture gamma-ray spectroscopy.
32 cl, 6 dwg
FIELD: nuclear physics; recording charged-particle associated neutrons in static-vacuum neutron generator.
SUBSTANCE: proposed semiconductor detector that can provide for recording charged-particle associated neutrons in static-vacuum neutron generator at recording speed of up to 107 particles per second has semiconductor recording element disposed in insulating case closed both on charged-particle flow end and on opposite end with metal layers electrically connected to current leads; current lead on charged-particle flow end is made in the form of stiff metal hold-down plate with holes opposite sensing zone of semiconductor recording element attached to insulating case; current lead connected at opposite end is made in the form of stiff metal plate pressed by means of spring-loaded member to semiconductor recording element; insulating case is made of vacuum-tight material of gas desorption capacity not over 5 x 10-8 millibar per cm-2 per sec-1; case may be made of ceramics.
EFFECT: enhanced recording speed.
2 cl, 3 dwg