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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This standard was proposed by the Ministry of Public Security of the People's Republic of China.
This standard is under the jurisdiction of the National Technical Committee on Security Precautions Alarm System of Standardization Administration of China (SAC/TC 100).
Technical requirements for X-ray computed tomography security inspection systems
1 Scope
This standard specifies system classification, technical requirements, test methods, inspection rules, marking and accompanying documents as well as packaging, transportation and storage of X-ray computed tomography security inspection system.
It applies to the X-ray computed tomography security inspection system and is the basis for the design, manufacture, acceptance and use of such equipment.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 191-2008 Packaging - Pictorial marking for handling of goods
GB/T 2423.1-2008 Environmental testing - Part 2: Test methods - Tests A: Cold
GB/T 2423.2-2008 Environmental testing - Part 2: Test methods - Tests B: Dry heat
GB/T 2423.3-2016 Environmental testing - Part 2: Testing method - Test Cab: Damp heat, steady state
GB/T 2423.5-1995 Environmental testing for electric and electronic products - Part 2: Test methods - Test Ea and guidance: Shock
GB/T 2423.10-2008 Environmental testing for electric and electronic products - Part 2: Test methods - Test Fc: Vibration (sinusoidal)
GB/T 4208-2017 Degrees of protection provided by enclosure (IP code)
GB 4793.1-2007 Safety requirements for electrical equipment for measurement, control and laboratory use - Part 1: General requirements
GB 15208.1-2018 Micro-dose X-ray security inspection system - Part 1: General technical requirements
GB 15208.2-2018 Micro-dose X-ray security inspection system - Part 2: Transmission baggage security inspection system
GB/T 17799.2-2003 Electromagnetic compatibility - Generic standards - Immunity for industrial environments
GB 17799.4-2012 Electromagnetic compatibility (EMC) - Generic standards - Emission standard for industrial environments
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
X-ray computed tomography
computed tomography
an imaging method for obtaining an internal cross-sectional image of an object through computer computation and processing by using a series of X-ray perspectives from different angles
3.2
X-ray computed tomography security inspection system
a product for imaging luggage and article by using an X-ray computed tomography method, which carries out reconstruction operation by obtaining the projection of an object at different viewing angles to obtain the tomographic image of the inspected object, thereby identifying the attenuation coefficient, density, equivalent atomic number and the like and giving the contraband alarm prompt
3.3
line pair
multiple parallel aluminum plates of the same size and at an interval equal to the plate thickness; the specification of line pair is expressed by the plate thickness (mm)
3.4
spatial resolution
ability of the system to identify and distinguish minor details of an object
Note: It is expressed by the maximum number of line pairs (lp/cm) within the unit distance that the system can recognize.
3.5
density resolution
ability of the system to distinguish substances of similar density
Note: It is expressed by the ratio of the absolute of the density difference between two substances to the density of the low density substance.
3.6
difference of atomic number measurements
δZ
difference in the atomic number measurements of the same substance of different sizes
It is calculated according to equation (1):
(1)
where
Z1, Z2——the mean of the atomic numbers on a tomographic image obtained by scanning two substances of different sizes.
3.7
relative deviation of test value
technical index used for measuring the measurement stability of a system, expressed by the test value under several conditions and their relative differences
3.8
test block
test object used for testing and evaluating the image performance index
3.9
test case
special suitcase used for holding the test block, which can pass through the entire system to complete the inspection of some performance indexes of the system
3.10
throughput rate
amount of baggage checked by the system in unit time
Note: It is expressed by the number of inspected baggage per hour (piece/h).
3.11
leakage of dose rate
strength of ionizing radiation passing through radiation shield and reaching the specified position at system exterior in unit time
Note: It is expressed by μGy/h.
3.12
contraband
threat with explosiveness, inflammability, corrosiveness or the like that endanger the security of various public places, as well as other articles that are banned to pass as determined by the user
3.13
threat image projection; TIP
threat image is randomly inserted into the scanned baggage image This is to assess the manual judgment ability of the judger.
3.14
secondary power source
power source for a secondary circuit, which is generated by power conversion of a system main input power source
4 System classification
According to the system's throughput rate index, the system is classified as follows:
a) high-speed inspection system;
b) medium-speed inspection system;
c) low-speed inspection system.
5 Technical requirements
5.1 Appearance and structure
5.1.1 The system shall have good appearance, i.e. the surface shall be flat, smooth, clean, uniform in color and free of obvious mechanical; damage, metal parts shall be protected from rusting and plastic parts shall be free from blistering and cracking;
5.1.2 The mark and character on the system surface and the display panel shall be clear and distinguishable.
5.1.3 The system frame shall have sufficient strength and rigidity and shall not be deformed or damaged during normal handling.
5.1.4 The degree of protection provided by enclosure shall not be inferior to IP20 in GB/T 4208-2017.
5.2 Performance indexes
5.2.1 Spatial resolution
The measured spatial resolution of the system shall be greater than or equal to 2.00lp/cm.
5.2.2 Density resolution
The density resolution of the system shall be less than or equal to 3%.
5.2.3 Difference of atomic number measurements (not applicable to single energy system)
The system shall make the difference in the atomic number measurements for the same substance of different sizes less than or equal to 15%.
5.2.4 Relative deviation of test value
The system shall make the relative deviation of test value for the water column test block placed respectively on the geometric center and edge of the bottom of the system channel meet:
a) not exceeding 15% if there is no interference and the size is same;
b) not exceeding 3% if there is interference and the size is same;
c) not exceeding 3% if there is no interference and the size is different.
5.2.5 Throughput rate
The throughput rate of different categories of systems shall meet those specified in Table 1 .
1 Scope
2 Normative references
3 Terms and definitions
4 System classification
5 Technical requirements
6 Test methods
7 Inspection rules
8 Marking and accompanying documentation
9 Packaging, transportation and storage
Annex A (Normative) Test case
