1、BRITISH STANDARD BS ISO 7004:2002 Photography Industrial radiographic films Determination of ISO speed, ISO average gradient and ISO gradients G2 and G4 when exposed to X- and gamma-radiation ICS 37.040.25 BS ISO 7004:2002 This British Standard, having been prepared under the direction of the Consum
2、er Products and Services Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 16 October 2002 BSI 16 October 2002 ISBN 0 580 40553 2 National foreword This British Standard reproduces verbatim ISO 7004:2002 and implements it as the
3、 UK national standard. It supersedes BS ISO 7004:1987 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee CPW/42, Photography, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secreta
4、ry. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of Brit
5、ish Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; presen
6、t to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an in
7、side front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 18, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 7004
8、:2002(E)INTERNATIONAL STANDARD ISO 7004 Second edition 2002-10-01 Photography Industrial radiographic films Determination of ISO speed, ISO average gradient and ISO gradients G2 and G4 when exposed to X- and gamma-radiation Photographie Films pour radiographie industrielle Dtermination de la sensibi
9、lit ISO, du contraste moyen ISO et des contrastes ISO G2 et G4 aprs exposition des rayons X ou gamma BSISO7004:2002BSISO7004:2002iiIS:4007 O2002(E) I SO 2002 All irthgs ersedevr iiiContents Page Foreword iv Introduction. v 1 Scope 1 2 Normative references 1 3 Terms and definitions. 1 4 Sampling and
10、storage. 3 5 Method of test 3 5.1 Principle . 3 5.2 Safelights . 3 5.3 Exposure 3 5.4 Processing . 5 5.5 Densitometry . 5 5.6 Evaluation 6 6 Product classification. 6 6.1 Speed calculation 6 6.2 Average gradient calculation . 9 6.3 Point gradient determination . 9 6.4 Uncertainty. 10 7 Marking and l
11、abelling 10 7.1 ISO speed. 10 7.2 ISO average gradient 10 7.3 ISO gradients G2 and G4 11 7.4 General . 11 Annex A (informative) Units of measured energy . 12 Annex B (informative) Scattered radiation measurement 13 Annex C (informative) Calibration of ionization chambers 14 Annex D (informative) Imp
12、rovement of the reproducibility of measurement of X-radiation. 15 Annex E (informative) Derivation of the relationship used in the determination of G2 and G4 . 16 Annex F (informative) Radiation quality code 17 Bibliography 18 BSISO7004:2002iiiIS:4007 O2002(E) vi I SO 2002 All irthgs ersedevrForewor
13、d ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technica
14、l committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of ele
15、ctrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires
16、 approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard
17、ISO 7004 was prepared by Technical Committee ISO/TC 42, Photography. This second edition cancels and replaces the first edition (ISO 7004:1987), of which it constitutes a technical revision. Annexes A to F of this International Standard are for information only. BSISO7004:2002ivIS:4007 O2002(E) I SO
18、 2002 All irthgs ersedevr vIntroduction This International Standard specifies methods for measuring the ISO speed, ISO average gradient and ISO gradients G2 and G4 of industrial radiographic film systems when exposed directly to X- and -radiation. Many countries have had national standards relating
19、to this subject for many years and may provide values which are different from those obtained by following the procedure specified in this International Standard. Because the photographic characteristics of a film system are dependent on the energy distribution in the wavelength spectrum, four repre
20、sentative sources are specified for determining sensitometric characteristics. To minimize the differences between national standards and this International Standard, the minimum requirements for X-ray tubes and X-ray generators have been considered mandatory and have been clearly specified in the s
21、ubclause on radiation quality (5.3.3). This International Standard imposes limiting specifications on the thickness of the metallic screens often used in conjunction with the film as specified in the basic rules for good radiographic practice in ISO 5579. Photographic results are also dependent on t
22、he chemical process used to develop the film. This International Standard does not attempt to specify the processing method; therefore, when ISO speed or ISO gradient values are given for a film system, it is necessary to specify not only the radiation quality used but also the process. This will pe
23、rmit the comparison of systems consisting of film and film processing. BSISO7004:2002vINTENRATIONAL TSANDADR IS:4007 O2002(E)I SO 2002 All irthgs ersedevr 1Photography Industrial radiographic films Determination of ISO speed, ISO average gradient and ISO gradients G2 and G4 when exposed to X- and ga
24、mma-radiation 1 Scope This International Standard specifies methods for determining sensitometric curve shape, ISO speed, ISO average gradient and ISO gradients G2 and G4 for industrial radiographic systems consisting of film and film processing when exposed directly to X-rays and -rays. The measure
25、ment of characteristics of film systems used in industrial radiography with fluorescent intensifying screens is not specified in this International Standard. NOTE Units of measured energy are given for information in annex A. 2 Normative references The following normative documents contain provision
26、s which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate th
27、e possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 5-2: 2001, Photography De
28、nsity measurements Part 2: Geometric conditions for transmission density ISO 5-3:1995, Photography Density measurements Part 3: Spectral conditions ISO 4037-1:1996, X and gamma reference radiation for calibrating dosemeters and doserate meters and for determining their response as a function of phot
29、on energy Part 1: Radiation characteristics and production methods ISO 5579: 1998, Non-destructive testing Radiographic examination of metallic material by X- and gamma rays Basic rules 3 Terms and definitions For the purposes of this International Standard, the following terms and definitions apply
30、. 3.1 radiographic film transparent plastic sheet coated on one or both sides with a photographically sensitive layer 3.2 film system system consisting of a radiographic film, the film processing and, when in use, the lead foil(s) and film holder BSISO7004:20021IS:4007 O2002(E) 2 I SO 2002 All irthg
31、s ersedevr3.3 system type all film systems manufactured in the same way and of the same specification, but without consideration of the format NOTE A particular system type is specified by the type of film, type of processing and, when in use, the type of lead foil(s) and film holder. 3.4 film/scree
32、n combination radiographic film in direct contact with metallic screen(s) during exposure to X- or g-radiation NOTE Within the scope of this International Standard, the screens are lead foils. 3.5 radiation quality characteristic of ionizing radiation, determined by its spectral distribution with re
33、spect to energy 3.6 exposure technique radiation source and filtration of the radiation beam in order to obtain a specified radiation quality at the source side of the film or film/screen combination holder 3.7 minimum density D min ISO standard visual diffuse transmission density, D T , of an unexp
34、osed and processed sample of the film under test 3.8 net density D N ISO standard visual diffuse transmission density, D T , of an exposed and processed film minus the minimum density, D min , of the film under test 3.9 speed quantitative measure of the response of the photographic material to radia
35、nt energy for specified conditions of exposure, processing and image measurement 3.10 average gradient G slope of the straight line joining two specified points on a sensitometric curve 3.11 gradient Gxslope dD/d log K of the tangent to the sensitometric curve at a specified net density D N= x NOTE
36、It is a measure of the contrast obtainable with the film system. 3.12 gray Gy special name for the unit of air kerma and the unit of absorbed dose, which is joule per kilogram NOTE 1 Gy = 1 J/kg of air. 1 Gy is equivalent to 114,5 R or is equivalent to 0,029 5 C/kg. BSISO7004:20022IS:4007 O2002(E) I
37、 SO 2002 All irthgs ersedevr 34 Sampling and storage In determining the sensitometric curve, ISO speed, ISO average gradient and ISO gradients G2 and G4 of a film system, it is important that the samples evaluated yield the average results obtained by users. This will require evaluating several diff
38、erent batches periodically under conditions specified in this International Standard. Prior to evaluation, the samples shall be stored according to the manufacturers recommendations for a length of time that simulates the average age at which the product is normally used. Several independent evaluat
39、ions shall be made to ensure the proper calibration of equipment and processes. The basic objective in selecting and storing samples as described above is to ensure that the film characteristics are representative of those obtained by a consumer at the time of use. 5 Method of test 5.1 Principle Sam
40、ples are exposed and processed as specified in 5.3 and 5.4. Measurements are obtained from the resultant images to produce a sensitometric curve from which values are taken and used to determine ISO speed, ISO average gradient and ISO gradients G2 and G4. 5.2 Safelights To eliminate the possibility
41、of safelight illumination affecting the sensitometric results, all films shall be handled in complete darkness during exposure and processing. 5.3 Exposure 5.3.1 Film holders Film/screen combinations shall be exposed in holders which provide less than 2 % absorption of the radiation specified (witho
42、ut taking into account lead screens). 5.3.2 Sample condition During exposure, the samples shall be at a temperature of 23 C 5 C and in equilibrium with air at a relative humidity of 50 % 20 %. 5.3.3 Radiation quality 5.3.3.1 General Four specific exposing sources (two X-ray sources and two g-ray sou
43、rces) are recognized in this International Standard to cover the range of exposing conditions used in practice. The selection of which of the four sources is used to determine ISO speed, ISO average gradient and ISO gradients G2 and G4 depends on how the film system is used. To improve the reproduci
44、bility of exposures when X-ray tubes are used, the X-ray generator shall fulfil the following requirements (based on ISO 4037-1): a) X-radiations shall be produced by an X-ray unit of the constant-voltage type; b) during an irradiation, the main value of the high voltage shall be stable within 1 %;
45、it should be possible to display the mean value of the high voltage with a tolerance of 1 %; c) the target of the X-ray tube shall be made of tungsten and shall be of the reflection type; the target angle should be about 22. BSISO7004:20023IS:4007 O2002(E) 4 I SO 2002 All irthgs ersedevr5.3.3.2 X-ra
46、ys from a low potential source The film/screen combination under test shall be exposed to X-rays from tungsten target tubes. Inherent filtration of the tube, plus an additional copper filter located as close to the target as possible shall provide a filtration equivalent to 2,0 mm 0,1 mm of copper.
47、All copper filters specified in this International Standard shall be made of 99,9 % pure copper. The potential across the X-ray tube shall be adjusted until the half-value absorption is obtained with 1,0 mm 0,1 mm of copper (i.e. the intensity of the X-ray beam with a filtration equivalent to 3,0 mm
48、 shall be one- half the value obtained with the total filtration equivalent to 2,0 mm of copper). A potential of approximately 120 kV generally meets this requirement. No lead screens shall be used. This is designated source (1). 5.3.3.3 X-rays from a high potential source The film/screen combinatio
49、n under test shall be exposed to X-rays from tungsten target tubes. Inherent filtration of the tube, plus an additional copper filter located as close to the target as possible shall provide a filtration equivalent to 8,00 mm 0,05 mm of copper. The potential across the X-ray tube shall be adjusted until the half- value absorption is obtained with 3,5 mm 0,2 mm of copper. A potential of approximately 220 kV generally meets th
