CN104570048A - Natural neutron spectrum measurement method - Google Patents
Natural neutron spectrum measurement method Download PDFInfo
- Publication number
- CN104570048A CN104570048A CN201410837765.0A CN201410837765A CN104570048A CN 104570048 A CN104570048 A CN 104570048A CN 201410837765 A CN201410837765 A CN 201410837765A CN 104570048 A CN104570048 A CN 104570048A
- Authority
- CN
- China
- Prior art keywords
- neutron
- natural
- detector
- counting rate
- background
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Measurement Of Radiation (AREA)
Abstract
The invention relates to a natural neutron spectrum measurement method, which comprises the following steps: using natural water body as a neutron moderation body, using a Monte-Carlo method for analog computation of fluence energy response functions of a detector to a natural neutron when the detector is located at different depths in the natural water body; using the detector to measure the counting rate of the natural neutron at different depths in the water; using spectrum unfolding software for spectrum unfolding on the basis of the counting rate after background deducting and the obtained fluence energy response functions to obtain a natural neutron spectrum. According to the natural neutron spectrum measurement method, the natural water body is used as as semi-infinite moderation body, the defects of limited size of conventional processed moderation body is overcome, the influences of neutrons and other background generated in the moderation body during natural neutron measurement are effectively eliminated, high-energy neutrons in the natural neutron spectrum can be effectively measured, the operation is simple, and reliable results can be provided.
Description
Technical field
The invention belongs to neutron measurement technology field, be specifically related to a kind of natural neutron spectral measurement method.
Background technology
Natural neutron is a part for natural radiation.Natural neutron flux energy range is roughly 0.0253eV-1000MeV, and energy crosses 11 orders of magnitude, natural neutron spectral measurement is the problem of a more complicated always.
Neutron detector conventional at present comprises threshold detector, uclear recoil type detector, nuclear reaction type detector, fission type detector.Usually, the measurement that a detector comparatively can only be satisfied with the neutron in specific energy district, as can be measured in district whole, must consider the combination of multiple detector (being polytype detector sometimes).Consider natural neutron fluence rate level low (about 0.01 neutron cm-2s-1), energy district is wide, and more options many balls neutron spectrometer is measured it and analyzed.
In the neutron spectrum measurement of many balls neutron spectromenter in radiation protection, Application comparison is extensive, is made up of the slow body of the sensitive probe of thermal neutron and a series of different size, different materials.Slow body is generally designed to spherical, and diameter is between 0 ~ 35cm, and the number of ball is between 5 ~ 18, and a thermal neutron detection element is put by ball center, such as 3He proportional counter, 6LiI, BF3 proportional counter etc., and slow body all selects polythene material.
As shown in Figure 2, have the Fluence energies response function curve of 12 probes in Fig. 2, all detectors all adopt diameter to be fill in 5.08cm stainless steel casing in typical Fluence energies response
10bF
3ionisation of gas room.1 and No. 2 probe is exposed (unshielded) and the ionization chamber with cadmium parcel respectively, and all the other probes are outside ionization chamber, be added with polythene material slow body.The overall diameter of slow body respectively is 7.6cm, 8.9cm, 10.2cm, 11.4cm, 12.7cm, 17.8cm, 20.3cm, 25.4cm and 30.5cm.As can see from Figure 2, after adding different slow body, detector will change to the response curve of neutron, along with slow body diameter increases, the moderating effect of incident neutron is become better and better, the peak position of energy response moves to right gradually, has the single detector of specific slow body size to the neutron-sensitive in specific energy district.In a given Neutron Radiation Field, the counting rate of each detector is uniquely determined by radiation field and response function, utilizes the measurement result analysis of multiple different detector and carries out spectrum unscrambling, can obtain the power spectrum of Neutron Radiation Field.
But, problem is both ways deposited: the slow body maximum gauge 1. selected during the neutron spectrum measurement of place is ~ 40cm when many balls neutron spectrometer is used for natural neutron spectral measurement, be used for the measurement of below 20MeV energy neutron, be difficult to meet request for utilization when natural neutron is measured, there is inconvenience part in the slow body that diameter is larger in processing, use procedure; If 2. slow body size diameter is more than 10cm, when measuring for natural neutron, should consider because the contribution of extra neutron that produces in detector inside of various elementary interaction, otherwise the problem such as the neutron fluence rate that analysis result can be caused to provide is higher, power spectrum is partially hard.
Summary of the invention
For the defect existed in prior art, the object of this invention is to provide a kind of natural neutron spectral measurement method, the method is without the need to processing the slow body of various sizes, simple to operate, high-energy neutron in natural neutron power spectrum effectively can be measured, provide reliable result.
For reaching above object, the technical solution used in the present invention is: a kind of natural neutron spectral measurement method, comprises the following steps:
Adopt natural water body as moderation of neutrons body, use monte carlo method analog computation to go out Fluence energies response function to natural neutron when detector is positioned at natural water body different depth;
Use the counting rate at detector measurement natural neutron different depth place under water;
Based on the counting rate after deduction " background " and the Fluence energies response function of acquisition, utilize Analysis software to carry out spectrum unscrambling, obtain natural neutron power spectrum
Further, it is characterized in that, described detector is He-3 proportional counter tube, BF3 proportional counter or containing lithium detector.
Further, the method of deduction " background " is: to about 0.5m below the water surface until in 20m depth range, measure different depth place neutron detector counting rate, to the counting rate recorded and depth data, utilization index Function Fitting is also extrapolated to 0-50cm place, underwater, obtain " background " counting rate of underwater 0-50cm depth, the counting rate obtained when detector being positioned at underwater 0-50cm deducts this " background " counting rate, obtains the counting rate after deducting " background ".
Method of the present invention utilizes natural water body as the large slow body of semiinfinite, overcome the deficiency that the slow body size of conventional machining is limited, can effectively deduct " backgrounds " such as the neutrons produced in slow body in natural neutron measuring process, high-energy neutron in natural neutron power spectrum effectively can be measured, simple to operate, provide reliable result.
Accompanying drawing explanation
Fig. 1 is the schematic diagram by curve and extrapolation method deduction " background " counting rate in the present invention, wherein L1 is the counting rate that the records experimental point curve with change in depth, L2 obtains the change curve of " background " counting rate with the degree of depth by curve and extrapolation method, and namely the difference of the two reflects the clean counting that above water body, natural neutron causes in detector.
Fig. 2 is the typical Fluence energies response curve of many balls neutron spectrometer.
Embodiment
Below in conjunction with the drawings and specific embodiments, the invention will be further described.
A kind of natural neutron spectral measurement method provided by the invention, comprises the following steps:
The first step, sunykatuib analysis.
Adopt natural water body as moderation of neutrons body, based on Monte Carlo analysis software, single-end neutron above sunykatuib analysis water surface explorer response situation of different depth place (below the such as water surface 0-50cm depth) in water body, obtains the Fluence energies response function that detector is positioned at various depth.
See approx, the neutron above the water surface approximately can only arrive underwater 50cm, then below, be almost the above " background " entirely, the response of below water surface 0-50cm depth therefore during spectrum unscrambling, only need be utilized to carry out analyzing.
The detector some degree of depth be positioned in water body can be considered as the Bonner ball added after a kind of slow body material of size, and the analog result of multiple degree of depth can be considered the response function of the many balls neutron spectrometer comprising a series of slow body size.
Second step, meter digit rate.
According to analog result, select different depth position in water body, such as 0cm, 2.5cm, 5cm, 10cm, 15cm, 20cm, 30cm, 50cm even depth, He-3 proportional counter tube, BF3 proportional counter can be utilized or measure containing lithium detector isotonic detector, obtaining the counting rate at different depth place.
During actual measurement, because cosmic rays etc. can produce the neutron of " additionally " in the slow body materials such as water body by interaction, detector also may be subject to the interference of other source rays simultaneously, and Electronics noice etc., at this, they are called " background " in the lump, in natural neutron spectral measurement and analysis, need the impact of deducting this part.
Consider that this " background " can describe with some simple continuous functions in underwater, its Changing Pattern can be predicted based on analysis of experimental data.Deduction background concrete grammar as follows: to below the water surface until in 20m depth range, choose the counting rate that 0.5m, 1m, 2m, 3m, 5m, 10m, 20m even depth measures neutron detector, to the counting rate recorded and depth data, utilization index function carries out curve fitting, obtain the Changing Pattern of degree of depth 0.5-20m scope inside counting rate with the degree of depth, obtained " background " counting rate at 0-50cm even depth place, underwater by the method for extrapolation, see curve L2.As can be seen from the curve L2 of Fig. 1, when natural neutron is measured, the counting rate that detector obtains is larger by " background " impact.For obtaining the true power spectrum of natural neutron, must deduct this " background ".Utilize the funtcional relationship of matching to extrapolate and directly can obtain " background " counting rate at 0-50cm place, underwater, the counting rate measurement result at respective depth place deduct this value can obtain deduction " background " counting rate after counting rate.As seen from Figure 1, in water body comparatively depths (as being greater than 50cm), the counting rate recorded overlaps substantially with " background " counting rate.
The counting rate C measured when i-th degree of depth
ican be expressed as:
Wherein,
for the neutron fluence rate of the energy group of jth in natural neutron power spectrum, unit cm
-2s
-1; R (E
j) for detector be E to energy when i-th degree of depth
jthe Fluence energies response function of single-end neutron, unit cm
2; R
bgi () is " background " counting rate when this place is measured, unit S
-1.
3rd step, spectrum unscrambling.
According to counting rate, Fluence energies response function after deduction " background ", utilize Analysis software to carry out spectrum unscrambling and obtain natural neutron power spectrum.This spectrum unscrambling process is the inverse process of formula (1).
The present invention is described in detail below with specific embodiment.
Embodiment
(1) Fluence energies response function sunykatuib analysis
Utilize Monte Carlo simulation software MCNP, GEANT4 etc., pass through sunykatuib analysis, obtain the single-end neutron of energy between 0.01eV to 1GeV incident from the water surface time below the water surface neutron flux spectrum of 0cm, 2.5cm, 5cm, 10cm, 15cm, 20cm, 30cm, 50cm depth, then can obtain response when detector is placed in relevant position according to neutron flux spectrum, obtain Fluence energies response function.
(2) measure
Select He-3 proportional counter as the sensitive detector of thermal neutron, different depth position place in water body, such as 0cm, 2.5cm, 5cm, 10cm, 15cm, 20cm, 30cm, 50cm, 1m, 2m, 3m, 5m, 10m, 20m place, is measured and is obtained the neutron count rate of these depths by analysis of spectrum.
(3) " background " deduction
The counting rate of 0.5m, 1m, 2m, 3m, 5m, 10m, 20m even depth place detector obtained in selecting step (2), utilization index function carries out Fitting Analysis to measurement result, obtains fitting formula.According to fitting formula extrapolation, obtain " background " value at 0-50cm place, underwater, and then obtain the net counting rate of 0cm, 2.5cm, 5cm, 10cm, 15cm, 20cm, 30cm, 50cm place, underwater detector.
(4) spectrum unscrambling
After net counting rate after obtaining deduction " background ", in conjunction with Fluence energies response function, Analysis software spectrum unscrambling is utilized to draw natural neutron power spectrum.
Above-described embodiment just illustrates of the present invention, and the present invention also can implement with other ad hoc fashion or other particular form, and does not depart from main idea of the present invention or essential characteristic.Therefore, description embodiment from the viewpoint of any all should be considered as illustrative but not determinate.Scope of the present invention should be illustrated by the claim of adding, any also should be within the scope of the present invention with the intention of claim and the change of scope equivalence.
Claims (3)
1. a natural neutron spectral measurement method, comprises the following steps:
Adopt natural water body as moderation of neutrons body, use monte carlo method analog computation to go out Fluence energies response function to natural neutron when detector is positioned at natural water body different depth;
Use the counting rate at detector measurement natural neutron different depth place under water;
Based on the counting rate after deduction " background " and the Fluence energies response function of acquisition, utilize Analysis software to carry out spectrum unscrambling, obtain natural neutron power spectrum.
2. a kind of natural neutron spectral measurement method according to claim 1, is characterized in that, described detector is He-3 proportional counter tube, BF3 proportional counter or containing lithium detector.
3. a kind of natural neutron spectral measurement method according to claim 1, it is characterized in that, the method of deduction " background " is: to about 0.5m below the water surface until in 20m depth range, measure different depth place neutron detector counting rate, to the counting rate recorded and depth data, utilization index Function Fitting is also extrapolated to 0-50cm place, underwater, obtain " background " counting rate of underwater 0-50cm depth, the counting rate obtained when detector being positioned at underwater 0-50cm deducts this " background " counting rate, obtains the counting rate after deducting " background ".
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410837765.0A CN104570048B (en) | 2014-12-29 | 2014-12-29 | A kind of natural neutron spectral measurement method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410837765.0A CN104570048B (en) | 2014-12-29 | 2014-12-29 | A kind of natural neutron spectral measurement method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104570048A true CN104570048A (en) | 2015-04-29 |
| CN104570048B CN104570048B (en) | 2017-03-29 |
Family
ID=53086562
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410837765.0A Active CN104570048B (en) | 2014-12-29 | 2014-12-29 | A kind of natural neutron spectral measurement method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104570048B (en) |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105785425A (en) * | 2016-04-26 | 2016-07-20 | 成都理工大学 | Water injection and drainage full-automatic multisphere neutron spectrometer and measurement method |
| CN108152845A (en) * | 2017-12-14 | 2018-06-12 | 中国计量科学研究院 | Dose Rate measuring method based on pulse-height spectrum |
| CN108490479A (en) * | 2018-02-09 | 2018-09-04 | 奕瑞新材料科技（太仓）有限公司 | A method of test radionuclide |
| CN108536983A (en) * | 2018-04-18 | 2018-09-14 | 中国科学院合肥物质科学研究院 | Accurate neutron energy spectrum based on discretized space Direction response matrix regulates and controls method |
| CN108680943A (en) * | 2018-05-11 | 2018-10-19 | 南京航空航天大学 | A kind of neutron spectrum measurement device and method based on prompt gamma ray neutron activation analysis technique |
| CN108957515A (en) * | 2018-09-18 | 2018-12-07 | 上海联影医疗科技有限公司 | Determine the method, apparatus and imaging system of the energy response function of detector |
| CN109154673A (en) * | 2016-05-24 | 2019-01-04 | 赛默飞世尔科学测量技术有限公司 | The mode of operation verification method of neutron detection device |
| CN111487670A (en) * | 2020-04-30 | 2020-08-04 | 成都理工大学 | Temperature-controlled fluid neutron spectrometer, measuring method thereof and analysis processing system |
| CN112420229A (en) * | 2020-11-18 | 2021-02-26 | 中国核动力研究设计院 | Out-of-pile nuclear instrument system periodic test device and test method thereof |
| CN112925006A (en) * | 2019-12-05 | 2021-06-08 | 核工业西南物理研究院 | Fusion neutron real-time energy spectrum resolution method for magnetic confinement device |
| CN113640854A (en) * | 2021-07-30 | 2021-11-12 | 中国原子能科学研究院 | Energy calibration method for gas detector by nuclear back-flushing method |
| CN113805217A (en) * | 2021-08-05 | 2021-12-17 | 中国原子能科学研究院 | Method and system for determining number of Li-6 atomic nuclei |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ATE56302T1 (en) * | 1984-09-05 | 1990-09-15 | Georg Vecsey | METHOD FOR THE PASSIVE TRANSFER OF HEAT FROM NUCLEAR REACTORS AND DEVICE FOR OPERATING SUCH METHOD. |
| CN1206837A (en) * | 1997-03-04 | 1999-02-03 | 安娜钻机国际有限公司 | Method for measuring earth stratum density |
| CN103064101B (en) * | 2013-01-04 | 2015-04-29 | 中国原子能科学研究院 | Gama scanning measuring method through adoption of asymmetrical standard sample calibration |
-
2014
- 2014-12-29 CN CN201410837765.0A patent/CN104570048B/en active Active
Cited By (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105785425A (en) * | 2016-04-26 | 2016-07-20 | 成都理工大学 | Water injection and drainage full-automatic multisphere neutron spectrometer and measurement method |
| CN105785425B (en) * | 2016-04-26 | 2018-08-03 | 成都理工大学 | A kind of full-automatic more ball neutron spectrometers of water filling draining and measurement method |
| CN109154673B (en) * | 2016-05-24 | 2022-04-19 | 赛默飞世尔科学测量技术有限公司 | Operating state verification method for neutron detection device |
| CN109154673A (en) * | 2016-05-24 | 2019-01-04 | 赛默飞世尔科学测量技术有限公司 | The mode of operation verification method of neutron detection device |
| CN108152845A (en) * | 2017-12-14 | 2018-06-12 | 中国计量科学研究院 | Dose Rate measuring method based on pulse-height spectrum |
| CN108490479A (en) * | 2018-02-09 | 2018-09-04 | 奕瑞新材料科技（太仓）有限公司 | A method of test radionuclide |
| CN108536983A (en) * | 2018-04-18 | 2018-09-14 | 中国科学院合肥物质科学研究院 | Accurate neutron energy spectrum based on discretized space Direction response matrix regulates and controls method |
| CN108680943A (en) * | 2018-05-11 | 2018-10-19 | 南京航空航天大学 | A kind of neutron spectrum measurement device and method based on prompt gamma ray neutron activation analysis technique |
| CN108680943B (en) * | 2018-05-11 | 2021-10-19 | 南京航空航天大学 | Neutron energy spectrum measuring device and method based on prompt gamma ray neutron activation analysis technology |
| CN108957515A (en) * | 2018-09-18 | 2018-12-07 | 上海联影医疗科技有限公司 | Determine the method, apparatus and imaging system of the energy response function of detector |
| CN108957515B (en) * | 2018-09-18 | 2020-09-08 | 上海联影医疗科技有限公司 | Method and device for determining energy response function of detector and imaging system |
| CN112925006A (en) * | 2019-12-05 | 2021-06-08 | 核工业西南物理研究院 | Fusion neutron real-time energy spectrum resolution method for magnetic confinement device |
| CN111487670A (en) * | 2020-04-30 | 2020-08-04 | 成都理工大学 | Temperature-controlled fluid neutron spectrometer, measuring method thereof and analysis processing system |
| CN111487670B (en) * | 2020-04-30 | 2022-03-01 | 四川轻化工大学 | Temperature-controlled fluid neutron spectrometer, measuring method thereof and analysis processing system |
| CN112420229A (en) * | 2020-11-18 | 2021-02-26 | 中国核动力研究设计院 | Out-of-pile nuclear instrument system periodic test device and test method thereof |
| CN112420229B (en) * | 2020-11-18 | 2022-02-22 | 中国核动力研究设计院 | Out-of-pile nuclear instrument system periodic test device and test method thereof |
| CN113640854A (en) * | 2021-07-30 | 2021-11-12 | 中国原子能科学研究院 | Energy calibration method for gas detector by nuclear back-flushing method |
| CN113640854B (en) * | 2021-07-30 | 2024-05-14 | 中国原子能科学研究院 | Nuclear recoil method gas detector energy scale method |
| CN113805217A (en) * | 2021-08-05 | 2021-12-17 | 中国原子能科学研究院 | Method and system for determining number of Li-6 atomic nuclei |
| CN113805217B (en) * | 2021-08-05 | 2024-05-14 | 中国原子能科学研究院 | Method and system for determining number of Li-6 atomic nuclei |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104570048B (en) | 2017-03-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104570048A (en) | Natural neutron spectrum measurement method | |
| Thomas et al. | Bonner sphere spectrometers—a critical review | |
| JP6255552B2 (en) | Neutron detector | |
| Torii et al. | Observation of gamma‐ray dose increase associated with winter thunderstorm and lightning activity | |
| CN107907901A (en) | The measuring method and system of nuclear power station neutron, gamma spectra and dosage | |
| CN105510956A (en) | Anti-Compton scattering detector | |
| CN106873024A (en) | A kind of highly sensitive environmental neutron energy spectrum analysis system for small sized pieces heap | |
| Gouda et al. | Calibration of well-type NaI (Tl) detector using a point sources measured out the detector well at different axial distances | |
| CN112904403B (en) | Wide-energy-spectrum neutron fluence online monitoring system | |
| Atanackovic et al. | Characterization of neutron fields from bare and heavy water moderated 252Cf spontaneous fission source using Bonner sphere spectrometer | |
| Gressier et al. | Characterization of a measurement reference standard and neutron fluence determination method in IRSN monoenergetic neutron fields | |
| Zhang et al. | The geometric factor of high energy protons detector on FY-3 satellite | |
| Brogi et al. | Feasibility of irrigation monitoring with cosmic-ray neutron sensors | |
| Weldon Jr et al. | Preliminary RAM-RODD results for the MUSiC subcritical configurations | |
| Sweany et al. | Above-ground antineutrino detection for nuclear reactor monitoring | |
| Cosack et al. | Dose equivalent survey meters | |
| CN212515056U (en) | Nuclear emergency multifunctional portable radiation monitoring system | |
| CN109814147B (en) | Method for measuring gamma radionuclide distribution around small hole by using detector and attenuator | |
| CN110687584B (en) | LSTM-based rapid nuclide identification method | |
| Badran et al. | An experimental method for the optimization of anti-Compton spectrometer | |
| Sheng et al. | Low-activity gamma source direction detection system based on NaI scintillator detector | |
| EP3987311A1 (en) | Personal wearable dosimeter for neutrons | |
| Tanimura et al. | Neutron fluence monitoring system in mono-energetic neutron fields at FRS/JAEA | |
| Mao et al. | Simulation of HTR-10 Anti-Compton HPGE Gamma-Ray Spectrometer With Geant4 | |
| Eakins et al. | A novel design of survey instrument for neutrons |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |