CN202662550U - Ionization chamber for directly measuring personal dose equivalent - Google Patents
Ionization chamber for directly measuring personal dose equivalent Download PDFInfo
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- CN202662550U CN202662550U CN 201220271260 CN201220271260U CN202662550U CN 202662550 U CN202662550 U CN 202662550U CN 201220271260 CN201220271260 CN 201220271260 CN 201220271260 U CN201220271260 U CN 201220271260U CN 202662550 U CN202662550 U CN 202662550U
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- ionization chamber
- dose equivalent
- personal dose
- plate
- header board
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Abstract
The utility model belongs to the technical field of dose measurement and discloses an ionization chamber for directly measuring personal dose equivalent. The ionization chamber mainly comprises a front plate, a middle plate, a protection ring, a collector, a back plate and a sensitive volume, and the key points are as follows: a main body of the ionization chamber is made of tissue equivalent material, and a back scattering part is arranged at the back end of the back plate; and the front plate of the ionization chamber, the middle plate of the ionization chamber and the back plate of the ionization chamber can be detached independently. The ionization chamber can directly measure the personal dose equivalent and has the advantages of good energy response and small drain current.
Description
Technical field
The utility model belongs to the dosage measurement technical field, is specifically related to
OnePlant the ionization chamber of directly measuring personal dose equivalent.
Background technology
In the relevant hot operation processes such as operation, maintenance and Isotope production of nuclear facility, practitioner's radiation protection is an indispensable important step.According to the regulation of China Basic Standard for Radiation Protection GB 18871-2002, radiation proof monitoring variable is the practical amount of radiation protection.
The practical amount of radiation protection is divided into again Neutron Ambient Dose Equivalent
H * (
d), directional dose equivalent
H ' (
d) and personal dose equivalent
H p(
d).Neutron Ambient Dose Equivalent and directional dose equivalent are used for place and environmental monitoring.Personal dose equivalent
H p (d)Be used for personal dose monitoring, i.e. appropriate depth below a certain specified point of human body
dThe dose equivalent of the soft tissue at place.According to the difference of the energy deposition situation of radiation in human body, the object that personal dose equivalent is measured is divided into again highly-penetrating radiation and weak penetrating radiation.For highly-penetrating radiation, the suggestion degree of depth
d=10mm is designated as
H p(10), for weak penetrating radiation, to the suggestion degree of depth of skin
d=0.07mm is to eye lens
d=3mm is designated as respectively
H p(0.07) and
H p(3).International standard ISO 4037-4 points out that its highly-penetrating radiation effect is mainly considered in the above photon radiation of 15keV.Therefore, for the consideration to the personnel protection secure context, to energy greater than the photon radiation of 15keV
H p(10) Accurate Determining of value has very important meaning.
The actual radiation monitoring instrument that uses is all wanted to calibrate in standard laboratory first basically, according to standard value monitoring instrument is calibrated, and finally realizes the monitoring of radiation dose.At present, need adopt dose equivalent as calibrator quantity to the calibration of radiation protection instrument in the world.
For measuring personal dose equivalent in standard laboratory, traditional method mainly is to utilize free-air ionization chamber and graphite cavity ionization chamber to measure the air kerma of photon radiation.Then according to employed radiation, the conversion coefficient of recommending in the choice criteria multiply by conversion coefficient with air kerma and obtains conventional true value, as shown in the formula:
In the formula:
H p(
d)---personal dose equivalent, usually get for highly-penetrating radiation
d=10mm, Sv;
h Pk---air kerma is to the conversion coefficient of personal dose equivalent, Sv/Gy;
K a---by the air kerma that the standard chamber is directly measured, Gy.
Utilize said method, for the radiation of single energy, the final personal dose equivalent uncertainty of determining is about 5%(k=2 generally speaking).But actual radiation field is to satisfy desirable single energy condition, even if the gamma-ray radiation source of monoenergetic, because the diffuse transmission influence on source container, air, laboratory wall and ground etc., also can make the tailored radiation source become the situation that in fact has certain spectral distribution, certainly will bring error to the use of conversion coefficient so, final so that the uncertainty increase of personal dose equivalent conventional true value.Especially for x-ray source, because x-ray source itself has certain spectral distribution, error can be larger, and such impact will be arrived a few percent.Be lower than the lower energy photon of 30keV even will arrive tens percent for energy.
A kind of more direct means that address this problem are to measure power spectrum, remove to calculate accurately conversion coefficient with real energy spectrum, and such method can guarantee that the uncertainty of the personal dose equivalent conventional true value measured is at 5%(k=2 in general) in.But measuring power spectrum itself is a very complicated job, at first need comparatively expensive spectral measurement equipment, secondly need to carry out spectrum unscrambling to measured pulse amplitude spectrum and calculate, it is very complicated to work, if require all standard laboratory all to carry out this work, be extremely difficult.
Summary of the invention
(1) utility model purpose
The utility model has proposed a kind of ionization chamber of direct measurement personal dose equivalent for the existing problem of prior art, and this ionization chamber can directly be measured personal dose equivalent, and energy response is good, leakage current is little.
(2) technical scheme
In order to solve existing problem in the prior art, the utility model provides a kind of ionization chamber of direct measurement personal dose equivalent, the agent structure of this ionization chamber is header board, middle plate, guard ring, collector, rear plate, and key is that the main body of this ionization chamber is made of tissueequivalentmaterial; Be air, i.e. sensitive volume between header board and the collector; The rear end of rear plate is equipped with the back scattering part; The various piece of ionization chamber is independently detachable.
Described tissueequivalentmaterial is polymethyl methacrylate, because polymethyl methacrylate tissue equivalent property is good, price is low, easy processing, so the utility model selects polymethyl methacrylate as tissueequivalentmaterial.Header board, middle plate, rear plate are threaded connection, and be independently detachable, and this ionization chamber can use the header board of different-thickness, middle plate, collector, rear plate to satisfy the measurement demand of different physical quantities.
Described header board is as high-pressure stage, and material is the polymethyl methacrylate that surface coverage has the graphite layer; Middle plate is as support section, and Main Function provides stable ionization space; Guard ring is used for reducing from the electric leakage of ionization chamber header board and makes electric field even; The effect of collector is the ionization electric charge of collecting to produce in sensitive volume, and back scattering is polymethyl methacrylate partly, is used for simulating trunk; Collector is connected with frame of reference by cable, and wherein the insulating material of cable is polymethyl methacrylate; Be equipped with aluminium film and angular response compensating plate in the front side of ionization chamber header board, wherein the effect of aluminium film is the low-energy component that reduces the ionization chamber front end.
(3) beneficial effect
The utility model provides a kind of ionization chamber of direct measurement personal dose equivalent, and the agent structure of this ionization chamber is polymethyl methacrylate, and the beneficial effect that adopts this ionization chamber measurement personal dose equivalent to have is: it is low, simple to operate that (1) measures cost.After the standard laboratory calibration, can directly measure personal dose equivalent
H p(10), because this ionization chamber can be measured personal dose equivalent in wider energy range, its calibration factor is more consistent, so can directly measure afterwards in calibration, makes and measures cost, simple to operate.(2) this ionization chamber measurement performance is good.It is little to leak electricity: leakage current is less than ± 5fA; Saturation characteristic is good: at 0.8mSvh
-1To 1.3Svh
-1The relative intrinsic error of response is less than 2% in the dose rate scope; Energy response is good: at the ratio of photon energy range this ionization chamber peak response and minimum response when 15keV is above less than 1.3.
Description of drawings
Fig. 1 ionization chamber cross sectional representation;
1. header board; 2. middle plate; 3. guard ring; 4. collector; 5. rear plate; 6. sensitive volume; 7. aluminium film; 8. angular response compensating plate; 9. back scattering part.
Embodiment
Below in conjunction with specification drawings and specific embodiments the utility model is further elaborated:
A kind of ionization chamber of measuring personal dose equivalent that connects, the agent structure of this ionization chamber is header board 1, middle plate 2, guard ring 3, collector 4, rear plate 5, key is that the main body of this ionization chamber is made of tissueequivalentmaterial; Be air between header board 1 and the collector 4, namely sensitive volume 6; The rear end of rear plate 5 is equipped with back scattering part 9; In ionization chamber header board 1, the ionization chamber behind plate 2, the ionization chamber plate 5 independently detachable.
Described tissueequivalentmaterial is polymethyl methacrylate, because polymethyl methacrylate tissue equivalent property is good, price is low, easy processing, so the utility model selects polymethyl methacrylate as tissueequivalentmaterial.Header board 1, middle plate 2, rear plate 5 are threaded connection, and be independently detachable, and this ionization chamber can use the sensitive volume of the header board of different-thickness and different size to satisfy the measurement needs of different-energy scope.
Described header board 1 is as high-pressure stage, and material is the polymethyl methacrylate that surface coverage has the graphite layer; Middle plate 2 is as support section, and Main Function provides ionization space; Guard ring 3 is used for reducing the electric leakage of ionization chamber header board 1; The effect of collector 4 is the electric charges of generation in sensitive volume 6 of collecting, and back scattering part 9 is polymethyl methacrylate, is used for simulating trunk; Collector 4 is connected with frame of reference by cable, and wherein the insulating material of cable is polymethyl methacrylate; Be equipped with aluminium film 7 and angular response compensating plate 8 in the front side of ionization chamber header board 1, wherein the effect of aluminium film is the low-energy component that reduces the ionization chamber front end.
Used ionization chamber in the present embodiment, front plate thickness is 11mm, and back scattering partly is the poly (methyl methacrylate) plate of 300mm * 300mm * 110mm, and the density of used poly (methyl methacrylate) plate is 1.19gm
-3After tested, its performance index that reach are as follows:
This ionization chamber leakage current is less than ± 5fA; Have good saturation characteristic, and in X and γ Reference radiation field, this ionization chamber is tested, such as table 1:
Table 1 personal dose equivalent
H p(10) ionization chamber is at N-15 ~ N-250, incidence angle 0
o~ 80
oModifying factor
The result shows: for average energy greater than 33keV, incidence angle 0
o~ 80
oPhoton in the scope, modifying factor
k(R.
α) between 0.95 ~ 1.13, i.e. the ratio of ceiling capacity response and least energy response less than require among the ISO 4037-4 1.2.And in 16keV ~ 24keV scope, incidence angle 0
o~ 80
oPhoton in the scope, modifying factor
k(R.
α) between 0.88 ~ 1.16; Be ceiling capacity response with the ratio of least energy response less than require among the ISO 4037-4 1.3.The satisfied directly measurement of this ionization chamber personal dose equivalent secondary standard ionization chamber can ring and wait the properties requirement.
Claims (4)
1. ionization chamber of directly measuring personal dose equivalent, the agent structure of this ionization chamber is header board (1), middle plate (2), guard ring (3), collector (4), rear plate (5), it is characterized in that the main body of this ionization chamber is made of tissueequivalentmaterial; Header board (1) is as high-pressure stage, and material is the polymethyl methacrylate that surface coverage has the graphite layer; Be air between header board (1) and the collector (4); Be equipped with back scattering part (9) in the rear end of rear plate (5); The material of agent structure and back scattering part (9) is polymethyl methacrylate.
2. the ionization chamber of a kind of direct measurement personal dose equivalent according to claim 1 is characterized in that, described header board (1), middle plate (2), rear plate (5) connect by the solid connected mode.
3. the ionization chamber of a kind of direct measurement personal dose equivalent according to claim 1 is characterized in that, described collector (4) is connected with frame of reference by cable, and wherein the insulating material of cable is polymethyl methacrylate.
4. the ionization chamber of a kind of direct measurement personal dose equivalent according to claim 1 is characterized in that, described header board (1) front side is equipped with aluminium film (7) and angular response compensating plate (8).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220271260 CN202662550U (en) | 2012-06-08 | 2012-06-08 | Ionization chamber for directly measuring personal dose equivalent |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220271260 CN202662550U (en) | 2012-06-08 | 2012-06-08 | Ionization chamber for directly measuring personal dose equivalent |
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| Publication Number | Publication Date |
|---|---|
| CN202662550U true CN202662550U (en) | 2013-01-09 |
Family
ID=47457436
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220271260 Expired - Lifetime CN202662550U (en) | 2012-06-08 | 2012-06-08 | Ionization chamber for directly measuring personal dose equivalent |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202662550U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103474323A (en) * | 2012-06-08 | 2013-12-25 | 中国原子能科学研究院 | Ionization chamber for directly measuring personal dose equivalent |
| CN108535757A (en) * | 2017-03-06 | 2018-09-14 | 中国辐射防护研究院 | A kind of detector that can measure two kinds of directional dose equivalent rates in radiation field simultaneously |
| CN111053978A (en) * | 2019-12-26 | 2020-04-24 | 上海联影医疗科技有限公司 | Ionization chamber and method for controlling temperature of ionization chamber |
-
2012
- 2012-06-08 CN CN 201220271260 patent/CN202662550U/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103474323A (en) * | 2012-06-08 | 2013-12-25 | 中国原子能科学研究院 | Ionization chamber for directly measuring personal dose equivalent |
| CN103474323B (en) * | 2012-06-08 | 2016-08-03 | 中国原子能科学研究院 | A kind of ionization chamber of direct measurement personal dose equivalent |
| CN108535757A (en) * | 2017-03-06 | 2018-09-14 | 中国辐射防护研究院 | A kind of detector that can measure two kinds of directional dose equivalent rates in radiation field simultaneously |
| CN108535757B (en) * | 2017-03-06 | 2022-07-29 | 中国辐射防护研究院 | Detector capable of simultaneously measuring two directional dose equivalent rates in radiation field |
| CN111053978A (en) * | 2019-12-26 | 2020-04-24 | 上海联影医疗科技有限公司 | Ionization chamber and method for controlling temperature of ionization chamber |
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|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130109 |