1、Designation: F 792 01e2Standard Practice forEvaluating the Imaging Performance of Security X-RaySystems1This standard is issued under the fixed designation F 792; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTENote from Table 1 was deleted editorially in February 2002.e2NOTEAn adjunct reference was added editorially in June 2002.1. Scope1.
3、1 This practice applies to all X-ray based screeningsystems, with tunnel apertures up to 1 m wide 3 1 m high,whether it is a conventional X-ray system or an explosivesdetection system (EDS) that provides a projection orprojection/scatter image for an operator to interpret.1.2 This practice applies t
4、o X-ray systems used for thescreening for prohibited items such as weapons, explosives,and explosive devices in baggage, packages, cargo, or mail.1.3 This practice establishes quantitative and qualitativemethods for evaluating the systems. This practice does notestablish minimum performance requirem
5、ents for any particu-lar application.1.4 The values as stated in SI units are to be regarded as thestandard.1.5 This practice relies upon the use of a standard test object(ASTM X-ray Test Object) to determine the applicable perfor-mance levels of the systems. The specific test object issubsequently
6、described and referred to in this document as the“Test Object.”1.6 This standard does not purport 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 applic
7、a-bility of regulatory limitations prior to use. Examples are Title21 Code of Federal Regulations, Section 1020.40 in the UnitedStates and Health seeTerminology E 1316).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
8、c differentiationthe ability of anX-ray system to penetrate through steel and differentiate on avideo monitor between organic materials of different effectiveatomic number.3.1.16 useful penetrationthe ability of an X-ray system topenetrate through aluminum and display, on a video monitor,wires that
9、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
10、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
11、 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
12、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
13、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
14、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
15、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 the Test Objectis provided in Table 1. Copies of the AutoCad drawings listedin Table 1 are
16、available 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
17、 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 plac
18、ed under aluminum which 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 typ
19、e, 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 th
20、em provides sufficient range to characterizethe 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 on top
21、 of steel which 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, the t
22、est 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 an X-
23、ray system, the test object incorporates a set offlat-bottom holes drilled into steel and plastic samples whichvary in thickness. The diameter of these holes, the depth ofF 7922these holes, and the thickness of the steel and plastic samplesprovides sufficient range to characterize the systems IQISen
24、sitivity. 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 deter-mine the organic/inorganic differentiation capability of anX-ray system, the test object incorporates a steel and pl
25、asticsample. For details regarding the steel and plastic samples referto 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 n
26、umbers butnominally 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 plastic placed on top ofsteel which varies in
27、thickness. For details regarding the steeland plastic 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 position of the test object for these tests shallb
28、e chosen to obtain the best picture possible. Additionallocations may be used as desired. The X-ray manufacturershould be consulted to establish the optimum location. Also, toachieve the best video image practical it may be necessary touse enhancement features such as Zoom, High Penetration, etc.Thi
29、s is an acceptable practice but for each test, the enhance-ment features used to meet the requirement must be recorded.The results of the following tests are to be retained as part ofFIG. 1 ASTM X-Ray Test Object Assembly PlanF 7923the system record and compared to performance requirementsor to prev
30、iously 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 observed on the monitor.6.3 Useful PenetrationScan the test object with the X-raysystem and record on the Log Sheet (Fig. 2) the ga
31、uge of all thewires, in Test 2, that can be observed 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 reco
32、rd 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 Sensit
33、ivityScan 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 picture displayed on the monitor. Observe if thereis a response difference betwe
34、en the steel and plastic samples.Record results on the Log Sheet (Fig. 2).6.9 Organic DifferentiationScan the test object with theX-ray system and study the picture displayed on the monitor.Observe if there is a response difference between successiveplastic samples. Record results on the Log Sheet (
35、Fig. 2).6.10 Useful Organic DifferentiationScan the test objectwith the X-ray system and study the picture displayed on themonitor. Record on the Log Sheet (Fig. 2) the thicknesses ofsteel through which there is a response difference betweensuccessive plastic samples.7. Evaluation Considerations7.1
36、GeneralUse of this practice does not guaranty that theX-ray system is operating properly. It is not intended to replacethe X-ray systems diagnostics. If problems are experiencedwith the system they must be resolved prior to operation.7.2 Training RequirementsTo effectively conduct theevaluation of a
37、n X-ray system it is recommended that theevaluator be trained to operate the system. The evaluator mustbe able to use all of the systems features to optimizeperformance and present the best picture practical.7.3 Test Object Location effective atomic number; explosivedevice; explosives; IQI; IQI sens
38、itivity; organic differentiation;organic/inorganic differentiation; radiation chamber; radiationmonitor; scatter block; security system; simple penetration;spatial resolution; thin organic imaging; useful organic differ-entiation; useful penetration; weapons; wire display; X-rayASTM International ta
39、kes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own r
40、esponsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addre
41、ssed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at t
42、he address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F 7926
