CN1187682A - Adjoint alpha neutron tube for logging - Google Patents
Adjoint alpha neutron tube for logging Download PDFInfo
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- CN1187682A CN1187682A CN98100264A CN98100264A CN1187682A CN 1187682 A CN1187682 A CN 1187682A CN 98100264 A CN98100264 A CN 98100264A CN 98100264 A CN98100264 A CN 98100264A CN 1187682 A CN1187682 A CN 1187682A
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Abstract
An adjoint alpha neutron tube for loggin well with C/O ratio energy spectrometry has a collector of adjoint alpha particle signals in the shape of ring, which is composed of multiple small alpha detectors around incident deuterium ion beam. Said small alpha detector structurally features that the one end of shaped optical glass conductor is welded to Kovar alloy tube and its another end is part of the side of circular mesa with inorganic scintillator sintered on it. Said neutron tube has particles leading-out and focus system composed of annular planar lenses. Its advantage is elimination of the influence from interference layer around probe, obtaining high correctness.
Description
The invention relates to a neutron generating device for well logging, in particular to a neutron tube for generating neutrons by adopting deuterium-tritium reaction.
In a carbon/oxygen ratio spectroscopy logging instrument, a neutron tube is used to generate fast neutrons. The working principle of the neutron tube is as follows: deuterium ions are generated by an ion source, accelerated and then hit on a tritium-containing target, and the following reactions are carried out: emitting fast neutrons at about 14 MeV. Bombarding a mineral bed around the cased well by using fast neutrons of 14MeV, and respectively emitting 4.43 and 6.13MeV non-ballistic characteristic gamma rays by using carbon and oxygen in the mineral bed; the ratio of the carbon content and the oxygen content in the ore bed can be obtained by measuring the energy spectrum and the relative intensity of the energy spectrum and the relative intensity. The oil content of the mineral layer around the oil well can be determined by the ratio of C/O and other relevant data. The existing neutron tube for carbon/oxygen ratio spectroscopy well logging, such as the neutron tube disclosed in chinese patent 88220224.3, CN2052573U, generally comprises an insulating housing, a penning ion source, an accelerating electrode and a target, wherein the penning ion source generates deuterium ions, the deuterium ions are accelerated and then hit on the tritium-containing target, fast neutrons are generated through the above reaction, and the fast neutrons bombard an ore bed around a cased well. The C/O ratio measured using such prior art logging devices has significant uncertainty. This is because when the logging device is put into a cased hole for measurement, the most sensitive region close to the gamma ray scintillation probe has about 60mm thick non-mineral substances (hereinafter referred to as interferent layer) such as water, iron, cement, etc., which contain a large amount of C, O, Si, Ca. The actual thickness of the mineral layer outside the cement casing is about 200mm (hereinafter referred to as effective mineral layer). Both calculations and measurements indicate that in the total characteristic gamma count, the contribution from the interfering layers such as cement casing, etc. is around 50%, and their role is equivalent to the background of the interfering effect, which brings great uncertainty to the C/O ratio.
The invention aims to design a neutron tube for well logging, and the neutron tube and a matched fast neutron flight time carbon/oxygen ratio well logging system can effectively reduce or remove the influence of the interference layer and greatly improve the accuracy of the C/O ratio.
The neutron tube comprises a sealed shell, a penning ion source, an accelerating electrode and a target, wherein the penning ion source, the accelerating electrode and the target are positioned in the sealed shell and fixed on the sealed shell, and the neutron tube is characterized in that an ion leading-out and focusing system is arranged between the penning ion source and the accelerating electrode, the accelerating electrode is positioned at an incident port of an ion beam flow pipeline, and a particle detector accompanied with α is arranged between the other end of the ion beam flow pipeline and the target and surrounds an ion beam flow line.
The principle of operation of the present invention is illustrated in fig. 1 and 4. Deuterium ions generated by the penning ion source 6 pass through the ion leading-out and focusing system 7, are accelerated by the accelerating electrode 8, are incident on the tritium target 17, and are emitted according to the principle To produce neutrons of about 14MeV0 1n) and α particles of about 3 MeV: (2 4He), the neutrons and α particles generated in association, according to the nuclear reaction kinematics, are in one-to-one correspondence, and emerge in opposite directions almost in a straight line, the neutrons that emerge at a forward tilt are incident on the gamma scintillation probe 20 and its surrounding materials (including the active mineral layer and the interferent layer), generating various characteristic gamma raysThe neutrons incident on the active mineral layer 19 are called active neutron population, the neutrons incident on the gamma scintillation probe 20 and the interferent layer 21 are called interfering neutron population, the corresponding associated α particles are emitted backwards along with α particles, which can be called active α particle population and interfering α particle population respectively, in the logging instrument, the gamma scintillation probe 20 should be as close to the tritium target as possible, the deuterium ions should be set to move along the Z-axis direction, the gamma scintillation probe 20 is behind the target on the Z-axis, the particle detector along with α should surround the Z-axis and be in front of the target, the interferent layer 19 and the active mineral layer 21 around the gamma scintillation probe 20, the projections on the X-Y plane are two adjacent rings, the gamma scintillation probe 20 itself and the interferent layer 19 should be as far as possible from the targetThe effective ore bed 21 should receive as many incident neutrons as possible, so that, according to the nuclear reaction kinematics, the α particle detector is made into a ring shape to most effectively receive an effective α particle group and not receive an interfering α particle group.
Of course α the particle detector may be a detector with an incomplete ring shape, but the detection efficiency is low.
Compared with neutron tube used in original logging instrument, the invention has associated α particle detector, which can select effective ore deposit area for measurement, so that the adverse effect of interference layer outside gamma scintillation probe can be reduced or eliminated, and the accuracy of measured C/O ratio can be improved
The invention is further explained by the embodiment in the following with the attached drawings.
FIG. 1 is a schematic view of the structure of the present invention.
FIG. 2 is a view showing the direction of the embodiment 1A.
FIG. 3 is a view showing the orientation of the preferred embodiment 2A.
Fig. 4 is a working principle diagram of the present invention.
In the figure, 1-an exhaust pipe 2A-a sealing insulator 2B-a sealing insulator 3A-a sealing kovar tube3B-a sealing kovar cover 4-a connecting piece 5-an insulating shell 6A-a penning source magnetic circuit system 6B-a penning source cathode magnetic steel 6C-a penning source cathode 6D-a penning source anode 6E-a penning source cathode 6F-a penning source cathode magnetic steel 7A-an ion extraction and focusing system first lens 7B-an ion extraction and focusing system second lens (focusing electrode) 7C-an ion extraction and focusing system third lens 8-an accelerating electrode 9-an ion beam pipeline 10-a memory shielding cover 11A-a gas memory 11B-a gas adsorber 12-a sealing kovar cover 13A-a sealing insulator 13B-a sealing insulator 14-a weld opening 15A- α detector sealing kovar tube 15B-a α detector glass light guide 15C- α detector body surface 16-a chamber sealing shell 17-a tritium target 18-a shielding body 19-an effective mineral layer 20-a gamma interference body 21-a gamma-a interference tube 21-a sealing insulator 23-a sealing kovar tube 23B-a sealing cover 23-a penning source
Example 1
As can be seen from FIG. 1, the components 1, 3A, 3B, 5, 12, 9, 15A, 16 and the sealing insulator form the sealed enclosure of the neutron tube of the present invention, the components 6A, 6B, 6C, 6D, 6E, 6F form the penning ion source 6, the penning ion source 6 is fixed to the sealed enclosure by the connecting member 4, the connecting member 4 can be made of non-magnetic stainless steel, the ion extraction and focusing system 7 is provided between the penning ion source 6 and the accelerating electrode 8, because the photomultiplier tube that produces the α detector and the optical signal that is assembled to measure α needs to occupy a space such that the ion transport length along with the α neutron tube is longer than that of the conventional neutron tube, and the measurement principle of the fast neutron time of flight carbon/oxygen ratio logging system along with α particles requires that the area of the tritium target is as small as possible, so that the overall view of the neutron tube is an approximately elongated collimated beam, the invention provides that between the penning ion source 6 and accelerating electrode 8 and the ion extraction and ion source is enclosed by a third lens 7, a cylindrical lens 7-7 is enclosed by a cylindrical lens, a cylindrical lens 7-7, a cylindrical lens is enclosed by a cylindrical lens, a cylindrical lens 7-7, a cylindrical lens is provided with a cylindrical lens, a.
The process for manufacturing an integral annular α detector is complex, a plurality of small detectors can be manufactured to form an annular, the four small detectors are adopted in the embodiment to form the annular detector, one end of a special-shaped glass light guide is welded on a Kovar alloy tube, the area and the shape of the section of the Kovar alloy tube are matched with those of a photomultiplier, the other end of the light guide is in the shape of a quarter of the side surface of a circular table, an inorganic scintillator is sintered on the side surface of the circular table, ZnS is adopted in the embodiment, the four small detectors are combined together, the detection end surfaces of the four small detectors form a complete circular table side surface which is used as a receiving surface of α particles, as shown in figure 2, the distances from the outer edge and the inner edge of the receiving surface to the center of a tritium target are equal, the received α particles are close, and.
Example 2
The structure of this embodiment is basically the same as that of embodiment 1, except that a circular glass sheet is welded to the kovar tube instead of the profiled glass light guide 15B in embodiment 1, and the detection receiving surface is shown in fig. 3.
Theoretical calculations and experimental conditions ofthe target rate in a deuterium ion beam are as follows.
The energy and the moving direction of ions at the outlet of the ion source are difficult to be given by an analytical expression, and the energy and the moving direction are simulated by a Monte Carlo method. Selecting a target with the diameter of 10mm, wherein the target and an accelerating electrode are at ground potential, and the potentials of an ion source cathode and a third lens are 115 +/-5 KV; the second lens is 3 to 5 kilovolts low relative to the ion source cathode. The aperture and the distance between each lens and each electrode are properly adjusted, the theoretically calculated target rate in the beam can reach about 85%, and the experimental measurement is about 82%.
The neutron intensity of a neutron tube α for well logging is 107The/second order, when used in a matched logging system, can obtain the carbon and oxygen characteristic gamma count of over 1000 CPS. The requirement of practical use is met. The basic principle of the neutron tube can also be applied to the field of other types of mine measurement.
Claims (9)
1. A well logging accompanying α neutron tube comprises a sealed shell, a penning ion source (6) positioned in the sealed shell and fixed on the sealed shell, an accelerating electrode (8) and a target (17), and is characterized in that an ion beam extraction and focusing system (7) is arranged between the penning ion source (6) and the accelerating electrode (8), the accelerating electrode (8) is positioned at an incident port of an ion beam pipeline (9), and an accompanying α particle detector (15) surrounds an ion beam streamline between the other end of the ion beam pipeline (9) and the target (17).
2. An accompanying α neutron tube according to claim 1, wherein the ion beam extraction and focusing system (7) is three annular planar lenses (7A, 7B, 7C).
3. The neutron tube α according to claim 2, wherein the planar lens (7A) is replaced by the bottom surface of the ion outlet of the penning ion source (6), the planar lens (7B) is a stainless steel cylindrical sheet with holes, and the planar lens (7C) is a non-magnetic stainless steel cylindrical cover with holes on the bottom surface and is fixed on the penning ion source (6).
4. The satellite α neutron tube of claim 1, 2 or 3, wherein the satellite α particle detector (15) is ring-shaped and is formed by welding a kovar tube (15A) and a shaped glass light guide (15B), the detection end face of the glass light guide (15B) is in a shape of a truncated cone, and a layer of inorganic scintillator is sintered on the detection end face.
5. The accompanying α neutron tube according to claim 1, 2 or 3, wherein the particle detector (15) of the accompanying α is formed by welding a kovar tube (15A) and a glass plate, and an inorganic scintillator is sintered on the kovar tube.
6. The adjoiner α neutron tube of claim 4, wherein the ring adjoiner α particle detector (15) is composed of several small detectors welded by kovar tube and shaped glass light guide, and surrounding the incident ion beam, the detecting end faces of all small detectors form a complete round table side.
7. The satellite α neutron tube of claim 5, wherein the satellite α particle detector (15) is comprised of a plurality of small detectors welded to a glass sheet using kovar tubes surrounding the incident ion beam.
8. The satellite α neutron tube of claim 6, wherein said ring satellite α particle detector is comprised of four small detectors welded together with a shaped glass light guide and a kovar alloy tube, the detecting end face (15C) of each light guide being a quarter of a truncated cone.
9. The particle neutron tube of satellite α of claim 7, wherein the satellite α particle detector comprises four small detectors welded together from round glass pieces and kovar tubes.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN98100264A CN1053763C (en) | 1998-01-23 | 1998-01-23 | Adjoint alpha neutron tube for logging |
| RU99100723/28A RU2199136C2 (en) | 1998-01-23 | 1999-01-14 | Neutron generator in sealed tube containing built-in detector of bound alpha particles for hole logging |
| US09/235,190 US6297507B1 (en) | 1998-01-23 | 1999-01-22 | Sealed tube neutron generator incorporating an internal associated-ALP |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN98100264A CN1053763C (en) | 1998-01-23 | 1998-01-23 | Adjoint alpha neutron tube for logging |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1187682A true CN1187682A (en) | 1998-07-15 |
| CN1053763C CN1053763C (en) | 2000-06-21 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN98100264A Expired - Fee Related CN1053763C (en) | 1998-01-23 | 1998-01-23 | Adjoint alpha neutron tube for logging |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1053763C (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101451433A (en) * | 2007-12-04 | 2009-06-10 | 普拉德研究及开发股份有限公司 | Hermetically sealed packaging and neutron shielding for scintillation-type radiation detectors |
| CN102129081A (en) * | 2010-12-23 | 2011-07-20 | 中国原子能科学研究院 | Accompanying alpha particle detector for sealing neutron generator |
| CN102794576A (en) * | 2012-08-24 | 2012-11-28 | 中国船舶重工集团公司第七一九研究所 | Sealing method for gas detectors |
| CN106098517A (en) * | 2016-07-29 | 2016-11-09 | 中国原子能科学研究院 | Miniature Penning ion source under a kind of highfield |
| CN108236760A (en) * | 2016-12-23 | 2018-07-03 | 南京中硼联康医疗科技有限公司 | Neutron capture treatment system |
| CN108934120A (en) * | 2017-05-26 | 2018-12-04 | 南京中硼联康医疗科技有限公司 | Target and neutron capture treatment system for neutron beam generating apparatus |
| CN111103615A (en) * | 2019-12-19 | 2020-05-05 | 厦门大学 | High-resolution photoelectronic speed imaging device |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4996017A (en) * | 1982-03-01 | 1991-02-26 | Halliburton Logging Services Inc. | Neutron generator tube |
| CN2052573U (en) * | 1988-11-21 | 1990-02-07 | 东北师范大学 | Ceramic setl-target neutron tube |
| CN1047237C (en) * | 1993-08-09 | 1999-12-08 | 清华大学 | Carbon/oxygen energy spectrum logging system |
| CN2204332Y (en) * | 1994-08-30 | 1995-08-02 | 东北师范大学 | Well-logging neutron-tube with alpha particle detector |
-
1998
- 1998-01-23 CN CN98100264A patent/CN1053763C/en not_active Expired - Fee Related
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101451433A (en) * | 2007-12-04 | 2009-06-10 | 普拉德研究及开发股份有限公司 | Hermetically sealed packaging and neutron shielding for scintillation-type radiation detectors |
| CN102129081A (en) * | 2010-12-23 | 2011-07-20 | 中国原子能科学研究院 | Accompanying alpha particle detector for sealing neutron generator |
| CN102129081B (en) * | 2010-12-23 | 2016-04-06 | 中国原子能科学研究院 | Accompanying alpha particle detector for sealing neutron generator |
| CN102794576A (en) * | 2012-08-24 | 2012-11-28 | 中国船舶重工集团公司第七一九研究所 | Sealing method for gas detectors |
| CN102794576B (en) * | 2012-08-24 | 2014-11-12 | 中国船舶重工集团公司第七一九研究所 | Sealing method for gas detectors |
| CN106098517A (en) * | 2016-07-29 | 2016-11-09 | 中国原子能科学研究院 | Miniature Penning ion source under a kind of highfield |
| CN108236760A (en) * | 2016-12-23 | 2018-07-03 | 南京中硼联康医疗科技有限公司 | Neutron capture treatment system |
| CN108236760B (en) * | 2016-12-23 | 2023-09-26 | 南京中硼联康医疗科技有限公司 | neutron capture therapy system |
| CN108934120A (en) * | 2017-05-26 | 2018-12-04 | 南京中硼联康医疗科技有限公司 | Target and neutron capture treatment system for neutron beam generating apparatus |
| CN108934120B (en) * | 2017-05-26 | 2024-04-12 | 南京中硼联康医疗科技有限公司 | Target for neutron ray generating device and neutron capturing treatment system |
| CN111103615A (en) * | 2019-12-19 | 2020-05-05 | 厦门大学 | High-resolution photoelectronic speed imaging device |
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| CN1053763C (en) | 2000-06-21 |
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