1、Designation: F792 08Standard Practice forEvaluating the Imaging Performance of Security X-RaySystems1This standard is issued under the fixed designation F792; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revisio
2、n.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice applies to all X-ray based screeningsystems, with tunnel apertures up to1mwide1mhigh,whether it is a conventional X-ray
3、system or an explosivesdetection system (EDS) that provides a projection orprojection/scatter image for an operator to interpret.1.2 This practice applies to X-ray systems used for thescreening for prohibited items such as weapons, explosives,and explosive devices in baggage, packages, cargo, or mai
4、l.1.3 This practice establishes quantitative and qualitativemethods for evaluating the systems. This practice does notestablish minimum performance requirements for any particu-lar application.1.4 This practice relies upon the use of a standard test object(ASTM X-ray Test Object) to determine the ap
5、plicable perfor-mance levels of the systems. The specific test object issubsequently described and referred to in this document as the“Test Object.”1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not p
6、urport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.22. Referenced Documents2.1 ASTM Standards:
7、3B258 Specification for Nominal Diameters and Cross-SectionalAreas ofAWG Sizes of Solid Round Wires Usedas Electrical ConductorsE1025 Practice for Design, Manufacture, and MaterialGrouping Classification of Hole-Type Image Quality In-dicators (IQI) Used for RadiologyE1316 Terminology for Nondestruct
8、ive ExaminationsE1647 Practice for Determining Contrast Sensitivity in Ra-diologyF1039 Test Method for Measurement of Low LevelX-Radiation Used in X-Ray Security Screening Systems(Withdrawn 2002)42.2 ASTM Adjuncts:30 Autocad Drawings52.3 Other Documents:Part 21 Code of Federal Regulations, Section 1
9、020.40 Cabi-net X-ray Systems (United States)6Health & Safety Regulation 1333 (United Kingdom)3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 contrast sensitivitya measure of the minimumchange in an object that produces a perceptible brightnesschange in the radiological image
10、on a monitor.3.1.2 effective atomic number (Z eff)the effective atomicnumber of a chemical compound or mixture of compounds is1This practice is under the jurisdiction of ASTM Committee F12 on SecuritySystems and Equipment and is the direct responsibility of Subcommittee F12.60 onControlled Access Se
11、curity, Search, and Screening Equipment.Current edition approved Oct. 1, 2008. Published November 2008. Originallyapproved in 1982. Last previous edition approved in 2001 as F792 012. DOI:10.1520/F0792-08.2Examples are Part 21 Code of Federal Regulations, Section 1020.40 in theUnited States and Heal
12、th & Safety Regulation 1333 in the United Kingdom.If film safety, defined as 2.5810-7C/kg (1 mR) per screening, is ofimportance, refer to Test Method F1039.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AST
13、MStandards volume information, refer to the standards Document Summary page onthe ASTM website.4The last approved version of this historical standard is referenced onwww.astm.org.5Available from ASTM International Headquarters. Order Adjunct No.ADJF0792.6Available from the United States Government P
14、rinting Office, 732 NorthCapitol St. NW, Washington, DC 20401.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization establi
15、shed in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1the atomic number of a single hypothetical element that wouldexhibit essentially identical X-ray attenuatio
16、n characteristics.3.1.3 explosivea material that can be detonated, that is,undergo a chemical reaction, expand suddenly, and create ashock wave.3.1.4 explosive devicea device containing explosives, adetonator, a timer/switch and an energy source.3.1.5 image quality indicator (IQI)in industrialradiog
17、raphy, a device or combination of devices whose dem-onstrated image or images provide visual or quantitative data,or both, to determine radiological quality and sensitivity.E13163.1.6 IQI sensitivityin radiography, the minimum discern-ible image and the designated hole in the plaque type or thedesig
18、nated wire image in the wire type IQI. E13163.1.7 organic differentiationthe ability of an X-ray systemto differentiate, on a video monitor, between organic materialsof different effective atomic numbers.3.1.8 organic/inorganic differentiationthe ability of anX-ray system to differentiate, on a vide
19、o monitor organic andinorganic matter.3.1.9 radiation chamberthe X-ray shielded enclosure inwhich an item is exposed to X-radiation.3.1.10 radiation monitoran instrument to measureX-radiation.3.1.11 scatter blocka block of soft wood (for example,pine or similar) that measures at least 300 mm by 300
20、mm by75 mm, used as X-ray scattering material to create a difficultcase when measuring radiation levels.3.1.12 simple penetrationthe ability of an X-ray system topenetrate through steel and display, on a video monitor, leadobjects that would otherwise be hidden by the steel.3.1.13 spatial resolution
21、the ability of an X-ray system todisplay as separate, on a video monitor, high contrast wiresseparated by a wire diameter (Line Pair Test Pattern; seeTerminology E1316).3.1.14 thin organic imagingthe ability of an X-ray systemto display, on a video monitor, thin organic material.3.1.15 useful organi
22、c differentiationthe ability of an X-raysystem to penetrate through steel and differentiate on a videomonitor between organic materials of different effective atomicnumber.3.1.16 useful penetrationthe ability of an X-ray system topenetrate through aluminum and display, on a video monitor,wires that
23、would otherwise be hidden by the aluminum.3.1.17 weapona device intended to do damage to person-nel or equipment without harming the attacker, but requiringthe attacker to physically activate the device. Examples includegun, knife and hand grenade.3.1.18 wire displaythe ability of an X-ray system to
24、display, on a video monitor, metal wires.4. Significance and Use4.1 This practice applies to and establishes a method tomeasure the imaging performance of X-ray systems used forthe screening for prohibited items such as weapons, explosivesand explosive devices in baggage, packages, cargo or mail.4.2
25、 This practice is intended for use by manufacturers toassess performance and by evaluators of security and contra-band screening X-ray systems to verify performance.4.3 This practice is intended to establish whether an X-raysystem meets the manufacturers specification or if the sys-tems performance
26、has deteriorated over time.4.4 This practice may be used for manufacturing control,specification acceptance, service evaluation or regulatory stat-utes.4.5 This practice is intended for use at both the point ofmanufacture and where the system is operated. The latterincludes locations such as securit
27、y checkpoints of transporta-tion terminals, nuclear power stations, correctional institutions,corporate mailrooms, government offices and other securityareas.4.6 The most significant attributes of this practice are thedesign of a standard Test Object and standard methods fordetermining the performan
28、ce levels of the system.4.7 In screening objects with X-ray systems video imagesare the primary inputs provided to operators. The better thequality of these images, the better the potential performance ofthe operator.5. Test Object5.1 The following describes the ASTM X-ray Test Object(Fig. 1) to be
29、used throughout the test procedures to determinethe applicable performance levels of a system. It was devel-oped to assess an X-ray based screening systems imagequality in 9 distinct areas.ADrawings Index for theTest Objectis provided in Table 1. Copies of the AutoCad drawings listedin Table 1 are a
30、vailable from ASTM International Headquar-ters.5.2 Test 1Wire DisplayTo determine how well an X-raysystem displays wires, the test object incorporates a set ofunobstructed wires. The gauge of these wires provides asufficient range to characterize the systems ability to displaywires. These wires are
31、laid out on the test object in a sinusoidalpattern. For details as to the type, quantity and gauge of thewires or regarding the spacing between each wire refer to Fig.1.5.3 Test 2Useful PenetrationTo determine the usefulpenetration of an X-ray system, the test object incorporates aset of wires place
32、d under aluminum that varies in thickness.The gauge of these wires and the thickness of the aluminumprovides sufficient range to characterize the systems UsefulPenetration. The wires shall be laid out on the test object, underan aluminum step wedge in a sinusoidal pattern. For details asto the type,
33、 quantity, gauge and spacing between the wires orregarding the thickness of the aluminum refer to Fig. 1.5.4 Test 3Spatial ResolutionTo determine the spatialresolution of an X-ray system, the test object incorporates a setof narrowly spaced wires. The gauge of these wires and thespacing between them
34、 provides sufficient range to characterizeF792 082the systems Spatial Resolution. For details as to the type,quantity, gauge or spacing between the wires refer to Fig. 1.5.5 Test 4Simple PenetrationTo determine the simplepenetration of an X-ray system, the test object incorporateslead digits placed
35、on top of steel that varies in thickness. Thethickness of the steel provides sufficient range to characterizethe systems Simple Penetration. For further details regardingthe test object refer to Fig. 1.5.6 Test 5Thin Organic ImagingTo determine the thinorganic imaging capability of an X-ray system,
36、the test objectincorporates plastic of various thicknesses. The thickness ofthe plastic provides sufficient range to characterize the sys-tems ability to image thin organic material. For detailsregarding the plastic samples refer to Fig. 1.5.7 Test 6IQI SensitivityTo determine the IQI sensitivityof
37、an X-ray system, the test object incorporates a set offlat-bottom holes drilled into steel and plastic samples that varyin thickness. The diameter of these holes, the depth of theseholes, and the thickness of the steel and plastic samplesprovides sufficient range to characterize the systems IQISensi
38、tivity. For details as to the diameter and depth of theseholes or regarding the thickness of the steel and plastic refer toFig. 1.5.8 Test 7Organic/Inorganic DifferentiationTo determinethe organic/inorganic differentiation capability of an X-raysystem, the test object incorporates a steel and plasti
39、c sample.For details regarding the steel and plastic samples refer to Fig.1.5.9 Test 8Organic DifferentiationTo determine the or-ganic differentiation capability of an X-ray system, the testobject incorporates various samples of plastic. The plasticschosen shall have different effective atomic numbe
40、rs butFIG. 1 ASTM X-Ray Test Object Assembly PlanF792 083nominally identical attenuation. For details regarding theplastic samples refer to Fig. 1.5.10 Test 9Useful Organic DifferentiationTo determinethe useful organic differentiation of an X-ray system the testobject incorporates various samples of
41、 plastic placed on top ofsteel that varies in thickness. For details regarding the steel andplastic samples used in this test refer to Fig. 1.6. Test Procedures6.1 The location and orientation of the test object in thefollowing procedures depends on the X-ray source and detectorarrangement. The posi
42、tion of the test object for these tests shallbe chosen to obtain the best displayed image possible. Addi-tional locations may be used as desired. The X-ray manufac-turer should be consulted to establish the optimum location.Also, to achieve the best video image practical it may benecessary to use en
43、hancement features such as Zoom, HighPenetration, etc. This is an acceptable practice but for each test,the enhancement features used to meet the requirement must berecorded. The results of the following tests are to be retained aspart of the system record and compared to performancerequirements or
44、to previously recorded results.6.2 Wire DisplayScan the test object with the X-raysystem and record on the Log Sheet (Fig. 2) the gauge of all thewires, in Test 1, that can be seen on the monitor.6.3 Useful PenetrationScan the test object with the X-raysystem and record on the Log Sheet (Fig. 2) the
45、 gauge of all thewires, in Test 2, that can be seen on the monitor.6.4 Spatial ResolutionScan the test object with the X-raysystem and record on the Log Sheet (Fig. 2) which sets ofvertical and horizontal wires can be resolved.6.5 Simple PenetrationScan the test object with the X-raysystem and recor
46、d on the Log Sheet (Fig. 2) the thicknesses ofsteel through which the lead numbers can be seen on themonitor.6.6 Thin Organic ImagingScan the test object with theX-ray system and record on the Log Sheet (Fig. 2) thethicknesses of the thin plastic object that can be seen on themonitor.6.7 IQI Sensiti
47、vityScan the test object with the X-raysystem and record on the Log Sheet (Fig. 2) which of the holesin the steel and the plastic steps can be seen.6.8 Organic/Inorganic DifferentiationScan the test objectand study the displayed image seen on the monitor. Observe ifthere is a response difference bet
48、ween the steel and plasticsamples. Record results on the Log Sheet (Fig. 2).6.9 Organic DifferentiationScan the test object with theX-ray system and study the displayed image seen on themonitor. Observe if there is a response difference betweensuccessive plastic samples. Record results on the Log Sh
49、eet(Fig. 2).6.10 Useful Organic DifferentiationScan the test objectwith the X-ray system and study the displayed image seen onthe monitor. Record on the Log Sheet (Fig. 2) the thicknessesTABLE 1 Test Object Drawing IndexSee adjunct ADJF0792.Item Number View Description Test Item Part Number DrawingCase ASTM X-Ray ObjectCase (Vert) Case 12 1 of 2Case ASTM X-Ray ObjectCase (Horizontal) Case 22 2 of 2Complete ASTMView 1 Test Object In Case Comp 13 1 of 3Complete ASTMView 2 Test Object In Case Comp 23 2
