Some standard content:
National Metrology Verification Regulations of the People's Republic of China J.1G933—1998
ApparatusforGammaRadiography1998—05—12Promulgated
Implementation1998—12—01
Promulgated by the State Administration of Quality and Technical Supervision
JJIG933—1996
Verification Rcgulation of
ApparatusforGammaRadiographsJJG 933—1998
This verification regulation was approved by the State Administration of Quality and Technical Supervision on May 12, 1998, and came into effect on December 1, 1998.
Responsible unit: National Technical Committee on Ionizing Radiation Metrology Drafting unit: Shanghai Institute of Metrology and Measurement Technology The drafting unit is responsible for interpreting the technical provisions of this regulation The main drafters of this regulation:
Liu Shulin
Tan Yongkang
.J.IG 933-1998
(Shanghai Institute of Metrology and Measurement Technology) (Shanghai Institute of Metrology and Measurement Technology) III
Technical requirements
Verification conditions
Verification items and verification methods
Processing of verification results and verification cycle
Appendix A Terminology
JG933-1998
Thanks to E? Some characteristics of common radiation sources for medical equipment Appendix C Test conditions for penetration sensitivity
(5)
JJG933-1998
Calibration procedures for radiographic flaw detectors
This procedure is applicable to the calibration of radiographic flaw detectors that are manufactured, in use and after repair and that use the penetration method for non-destructive testing: commonly used radioactive nuclides such as 0Co, 137Cs, 192Ir and 10Tm, etc.: all are subject to
1 Application and structure
? X-ray flaw detector (hereinafter referred to as X-ray flaw detector) is a device that uses X-ray non-photographic detection methods to detect internal defects of materials, components or equipment. It is mainly composed of three parts: a sealed radioactive source and its penetrator, an irradiation head and a remote control device.
2 Principle
? The radiation emitted by the radioactive source is weakened when irradiating the object to be inspected. The degree of radiation is different at the defective part of the object to be inspected and at other parts. Based on this principle, radiography can be used to show the defects in the inspected objects such as welded parts and components, and to show the location, size, shape and type of the defects. 3 Classification
3.1 According to the mobility of the source container, the flaw detector can be divided into three types: portable, mobile and fixed. 3.2 According to the way the radioactive source is transferred from the safe position to the working position, the flaw detector can be divided into two types: the first type uses the rotation of the radioactive source in the source container or the opening of the source container screen to put the flaw detector in the output state, and the emitted rays are usually collimated; the second type uses mechanical transmission, electric or pneumatic methods to eject the radioactive source from the source container, and transmits it to the irradiation head through the output source pipe for irradiation. The emitted rays are collimated or non-collimated. Technical requirements
4: General requirements
4.1 The mechanical, safety and other performances of the flaw detector shall meet the requirements of the corresponding standards. 4.2 There should be a conspicuous and permanent ionizing radiation mark on the source container of the detector, and the maximum activity value of the radioactive nuclei allowed by the container should be indicated. 4.3 The nominal activity value of the radioactive nuclei used in the detector and its measurement period must be stated at the appropriate position of the detector or in the accompanying technical documents. Equivalent activity The equivalent activity of the irradiated radioactive source shall not exceed the maximum activity value allowed by the source container, and shall not differ from the nominal activity value after static measurement by more than 3%. 6 Repeatability The repeatability of the organic radiation beam output expressed by the relative standard deviation of multiple measurements shall not be greater than 3%. To ensure the uniformity of the irradiation field, the change of the air kerma rate within 5T from the center point of the plane at a certain distance from the radiation source and perpendicular to the central axis of the useful radiation beam should not exceed ±5%: 333-1998: For non-radiation, the "central axis" refers to the reference point selected by the source. (Sub-division) Transmission sensitivity Under the irradiation conditions and film processing conditions specified in the appendix, the transmission sensitivity of the flaw detector to the steel flat plate test block of specified thickness should exceed the value specified in Table 1. Table 1: Electrostatic chamber dosimeter Test block mm Three specified conditions Sensitivity () The range of the air kerma function should be at least 1-1 (H) mGy, the expanded uncertainty of the relative ion is not more than 5% (K=2).
Steel flat electrode test blockWww.bzxZ.net
Made of 2, steel, the precision error does not exceed ± 1.1 mm, the surface roughness Ra is not more than 6.3 μm.11
Photographic film and upper washing, measuring and reading equipment
Including radiographic film, darkroom equipment, film viewing lamp and black meter, etc. Other juice instruments
Other measuring instruments required for calibration are shown in Table 25 Table 2
Thermometer
Environmental cleaning parts
o -- 50 t.
86-106 kPa
U--1 uo s
Minimum division value
The calibration of the instrument can be carried out in the metrological calibration laboratory or on site. The environmental conditions during calibration should be able to ensure that the Y flaw detector and the dose can work properly: JJG9331998
IV. Calibration items and calibration methods
14 Equivalent compliance
14.1 Ensure that the detector is installed so that the radioactive source in the working position is about 1.51 above the ground and is in a fixed state.
14,2 Place the dose chamber at a certain distance from the radioactive source on the central axis of the useful radiation bed: The distance should be selected to meet the requirements of the point source, so that the amount of scattering radiation on the measuring base does not exceed 5% of the total air ratio kinetic energy rate, generally 1me
14.3 Use ionization chamber dose year Measure the air kerma of the dosimeter at least three times: calculate the average value of the measured values. 14.4 Calculate the equivalent activity of the Y radioactive source using formula (1): A
where: A
MN·Kr·Ks
Y equivalent activity of the radioactive source, FA
distance from the center of the radioactive source to the center of the ionization chamber, r1 the number of air kerma bands of the radioactive decay, ms the average value of the values measured by the dosimeter, di-l, where dv represents the scale value: the air kerma of the dosimeter Gvdiv-! (1)
is the air density correction factor, whose value is calculated by temperature T (unit length) and air pressure (unit ka) using formula (2):
For sealed ionization chambers, K=1;
K is the environmental sensitive radiation correction factor.
The calculated values of 4 shall meet the requirements of Article 5 of this specification. 15 Complexity
15.1 Fix the center chamber of the dosing vehicle as the center axis of the useful radiation beam about 60 degrees away from the radiation source, send a fixed tracking light back, and start the detector 10 times to perform safety measurements: 15.2 Calculate the relative energy deviation V of the single measurement according to formula (3): I(M, - Ry
Where: M,
the value measured by the first software;
the average value of the 1st measured value.
The repeatability expressed by V value shall not exceed 3%. 16 Uniformity of radiation field
JJG 933—1998
16,1 Place the ionization scope of the dose meter at a certain point P on the central axis of the useful radiation beam, the distance from this point to the center of the radiation source is about 60cm, and measure the air kerma efficiency rate at point P. 16.2 On the half plane passing through point P and perpendicular to the central axis of the useful radiation beam, select 4 points that are evenly distributed and 5m away from point P, and measure the air kerma efficiency rate of these points respectively: 16.3 The ratio of the air kerma efficiency rate of the above 4 points to the air kerma efficiency rate of point P should fall within the range of 0.95-1.0.
16.4 (The uniformity of the radiation field can also be measured by the film dose method . 17 Transmitter sensitivity
17.1 Place a steel flat test block with the original sensitivity specified in Table 1 in the radiation field so that the central axis of the radiation is perpendicular to the plate and passes roughly through the center of the test block. The distance from the effective radiation source to the recommended photographic film is determined according to the table in the Appendix (.
17.2 In the middle of the flat test block, a linear image quality meter is placed on one side of the radiation source, and a photographic film with a lead intensifying screen is placed on the back. The type of film and the grid of the image quality meter and the intensifying screen meet the requirements of the Appendix: 17.3 Select an appropriate irradiation time for thick light so that the illumination of the film obtained after darkroom processing is 1.% minus 0.3 The background gray is less than 0.3
17.4 Carry out film processing and reading according to the conditions specified in Appendix C: the ratio of the minimum steel wire diameter of the image quality meter that can be distinguished from the film to the thickness of the steel flat test block (calculated using a percentage table) is the transillumination sensitivity, and its value should meet the requirements of Article 8 of this Regulation.
5. Processing of calibration results and calibration cycle
18. Processing of calibration results
18.1 A calibration certificate shall be issued to the detector that has passed the calibration in accordance with this Regulation, and a calibration result notice shall be issued to the detector that has failed the calibration
18.3 If all the inspections meet the technical requirements, they shall be judged as qualified. If one or more of the three requirements in Articles 14, 15 and 1G do not meet the requirements, they shall be judged as unqualified. 18.3 If only one of the requirements in Article 17 does not meet the technical requirements, the sensitivity shall be re-measured according to the actual radiation cases and film washing conditions used by the user. If it still does not meet the requirements, it is judged as unqualified; if it meets the requirements after retesting, it is deemed qualified, but the actual conditions of use must be stated in the calibration results. 19 Calibration cycle
19, 1 The calibration cycle of the flaw detector using C, 1\ or 11m radioactive sources is 1 year: the calibration cycle of the flaw detector using 1%I is an average of 1 year,
19.2 The average activity of the inspection items belongs to the first calibration items, and other items are mandatory items for the first calibration and subsequent calibration.
19.3 The detector should be recalibrated after the replacement of the radioactive source or after repairs that may cause significant changes in performance. The recalibration after the source is replaced should include the calibration of equivalent activity. 4
Appendix A
1 Equivalent activity
JJG933—1996
The equivalent activity of a radioactive source is equal to the cleanliness of a point source of radionuclides with the same product at the same distance from the air with the same specific energy release rate.
2 Maximum activity value
In order to verify the normal operation of the detector and the safety of the blast, the upper limit of the activity of a radioactive source of a specific nuclide allowed to be installed in the source container
3 Irradiation head
The shielding of the sealed radioactive source is placed at the selected working position: 4 Working position
The position of the sealed radioactive source when the blast detector is used for irradiation. S safe position
? The position of the sealed radioactive source in the shielding container when the blast detector stops working, also known as the storage position. 6 Air kerma rate number
For radioactive elements that emit photons, the air kerma rate number is the quotient of IK divided by A, where K is the air kerma rate caused by the decay of a point source of activity A at a distance I, i.e.:
Unit: m2 Gy Bg-1s-1,
? Transillumination sensitivity
The ratio of the minimum fast-falling line of the object to be inspected along the ray direction that can be measured by the radiographic transillumination method to the thickness of the transillumination sheet, expressed as a percentage. The transillumination sensitivity measured by the image quality meter is higher than the sensitivity that can actually be achieved to detect defects in the object.
Appendix B
JJG 933—1998
Some characteristics of radioactive materials commonly used in flaw detectors: 13TCs, 192Ir and 17nTm. The half-life I, β-ray energy Eg, north-beam energy Eg, and air kerma rate constant T are listed in the following table. Floor
,(Mev)
1.17. 1.33
0.052.0.084
Fa tm'Gy Ba-ls--)
8.61 ×1017
2.17#10-17
3.08×1017
1.97×1019
Appendix℃
JIG 933-1 No. 98
Test conditions for remote illumination sensitivity
Virtual illumination sensitivity is an important index that characterizes the ability of a radiographic flaw detector to detect internal defects in an object under test. Its value is not only related to the characteristics of the object under test and its defects, but also affected by many factors such as radiation properties and film processing conditions. The measurement of the remote illumination sensitivity of a flaw detector using a linear image quality meter should be carried out under the conditions specified in this appendix. 1 Source to Film Distance
The distance from the radioactive source to the photographic film is determined according to the following table: Radioactive source
2 Flat test block
Distance from the radioactive source to the filmcn1
Lead screen thickness mm
Linear image quality meter specifications
FEInrFEa
The steel plate test block's precision and error shall meet the requirements of Article 8 and Article 10 of this Regulation respectively. If it is a non-standard test block, its length and width shall not be less than 15cm and 10cm3 Photographic film
Use type 3 industrial radiographic film, i.e. film with ten-grade grain and medium sensitivity. 4 Lead intensifying screen
Use a lead intensifying screen with the thickness of the front and rear screens as specified in the above table. 5 Linear image quality meter
The process technology of the velvet image quality meter shall meet the requirements of G15618-1985, and measure 6C0? The sensitivity of the flaw detector should be measured by two sets of image quality meters at the same time. The 137s, [21 or 170m detector only needs one set of image quality meters. The specifications of these image quality meters are shown in the table above.
6 Film processing
Use appropriate developer and fixer according to the film model. The normal temperature is (20+2) and the developing time is about 5min (for industrial washing).
Film observation
JG 933—1998
Film observation conditions should meet the requirements of relevant standards. Additional notes: This verification procedure has been approved by the National Ionization Radiation Metrology Technical Committee.(Mev)
1.17. 1.33
0.052.0.084
Fa tm'Gy Ba-ls--)
8.61 ×1017
2.17#10-17
3.08×1017
1.97×1019
Appendix ℃
JIG 933-1 No. 98
Test conditions for remote illumination sensitivity
Virtual illumination sensitivity is an important index that characterizes the ability of a radiographic flaw detector to detect internal defects in an object under test. Its value is not only related to the characteristics of the object under test and its defects, but also affected by many factors such as radiation properties and film processing conditions. The measurement of the remote illumination sensitivity of a flaw detector using a linear image quality meter should be carried out under the conditions specified in this appendix. 1 Source to Film Distance
The distance from the radioactive source to the photographic film is determined according to the following table: Radioactive source
2 Flat test block
Distance from the radioactive source to the filmcn1
Lead screen thickness mm
Linear image quality meter specifications
FEInrFEa
The steel plate test block's precision and error shall meet the requirements of Article 8 and Article 10 of this Regulation respectively. If it is a non-standard test block, its length and width shall not be less than 15cm and 10cm3 Photographic film
Use type 3 industrial radiographic film, i.e. film with ten-grade grain and medium sensitivity. 4 Lead intensifying screen
Use a lead intensifying screen with the thickness of the front and rear screens as specified in the above table. 5 Linear image quality meter
The process technology of the velvet image quality meter shall meet the requirements of G15618-1985, and measure 6C0? The sensitivity of the flaw detector should be measured by two sets of image quality meters at the same time. The 137s, [21 or 170m detector only needs one set of image quality meters. The specifications of these image quality meters are shown in the table above.
6 Film processing
Use appropriate developer and fixer according to the film model. The normal temperature is (20+2) and the developing time is about 5min (for industrial washing).
Film observation
JG 933—1998
Film observation conditions should meet the requirements of relevant standards. Additional notes: This verification procedure has been approved by the National Ionization Radiation Metrology Technical Committee.(Mev)
1.17. 1.33
0.052.0.084
Fa tm'Gy Ba-ls--)
8.61 ×1017
2.17#10-17
3.08×1017
1.97×1019
Appendix ℃
JIG 933-1 No. 98
Test conditions for remote illumination sensitivity
Virtual illumination sensitivity is an important index that characterizes the ability of a radiographic flaw detector to detect internal defects in an object under test. Its value is not only related to the characteristics of the object under test and its defects, but also affected by many factors such as radiation properties and film processing conditions. The measurement of the remote illumination sensitivity of a flaw detector using a linear image quality meter should be carried out under the conditions specified in this appendix. 1 Source to Film Distance
The distance from the radioactive source to the photographic film is determined according to the following table: Radioactive source
2 Flat test block
Distance from the radioactive source to the filmcn1
Lead screen thickness mm
Linear image quality meter specifications
FEInrFEa
The steel plate test block's precision and error shall meet the requirements of Article 8 and Article 10 of this Regulation respectively. If it is a non-standard test block, its length and width shall not be less than 15cm and 10cm3 Photographic film
Use type 3 industrial radiographic film, i.e. film with ten-grade grain and medium sensitivity. 4 Lead intensifying screen
Use a lead intensifying screen with the thickness of the front and rear screens as specified in the above table. 5 Linear image quality meter
The process technology of the velvet image quality meter shall meet the requirements of G15618-1985, and measure 6C0? The sensitivity of the flaw detector should be measured by two sets of image quality meters at the same time. The 137s, [21 or 170m detector only needs one set of image quality meters. The specifications of these image quality meters are shown in the table above.
6 Film processing
Use appropriate developer and fixer according to the film model. The normal temperature is (20+2) and the developing time is about 5min (for industrial washing).
Film observation
JG 933—1998
Film observation conditions should meet the requirements of relevant standards. Additional notes: This verification procedure has been approved by the National Ionization Radiation Metrology Technical Committee.
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