1、January 2013 Translation by DIN-Sprachendienst.English price group 14No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).IC
2、S 17.240!$L“1934159www.din.deDDIN ISO 12789-1Reference radiation fields Simulated workplace neutron fields Part 1: Characteristics and methods of production (ISO 12789-1:2008),English translation of DIN ISO 12789-1:2013-01Referenzstrahlungsfelder Simulierte Arbeitsplatz-Neutronenfelder Teil 1: Eigen
3、schaften und Erzeugungsverfahren (ISO 12789-1:2008),Englische bersetzung von DIN ISO 12789-1:2013-01Champs de rayonnement de rfrence Champs de neutrons simulant ceux de postes de travail Partie 1: Caractristiques et mthodes de production (ISO 12789-1:2008),Traduction anglaise de DIN ISO 12789-1:2013
4、-01www.beuth.deDocument comprises pagesIn case of doubt, the German-language original shall be considered authoritative.2812.12 DIN ISO 12789-1:2013-01 A comma is used as the decimal marker. Contents 2 Page National foreword .3 National Annex NA (informative) Bibliography 3 Introduction .4 1 Scope 5
5、 2 Normative references 5 3 Terms and definitions .5 4 Simulated workplace neutron fields 7 5 General requirements for the production of simulated workplace neutron spectra 7 6 Characterization of simulated workplace neutron fields 8 7 Fluence to dose-equivalent conversion coefficients 10 8 Sources
6、of uncertainty . 11 9 Expression and reporting of uncertainties 11 Annex A (informative) Examples of simulated workplace neutron fields 12 Bibliography . 26 Figures Figure A.1 Schematic diagram of the PTB irradiation facility (vertical cross-section) . 15 Figure A.2 Fluence rate spectra behind a sha
7、dow object for various calibration sources in the PTB 16 Figure A.3 Schematic cross-sectional view of the IPSN-CEA Cadarache Laboratory simulated workplace neutron field facility . 17 Figure A.4 Measured and calculated neutron spectra produced at the IPSN-CEA Cadarache facility (238U-induced fission
8、 by 14,6 MeV neutrons with additional moderation) . 18 Figure A.5 Neutron spectrum measured at the IPSN-CEA Cadarache facility . 19 Figure A.6 GRENF facility (horizontal cross-section at the plane of the beam) . 20 Figure A.7 Unfolded spectral neutron fluence per log energy interval in the GRENF fac
9、ility 21 Figure A.8 Plan view of SILNE reactor facility (ground view) 22 Figure A.9 Neutron spectra produced at the reference position using different shields in the SILNE facility 23 Figure A.10 Cross-sectional diagram of the CERN reference neutron facility (vertical cross-section) 24 Figure A.11 C
10、alculated and measured neutron energy spectra produced in the CERN facility . 25 Tables Table 1 Ambient and personal dose equivalent per unit neutron fluence, h*(10) and hp, slab(10,), in units of pSvcm2, for monoenergetic neutrons incident on the ICRU sphere and ICRU tissue slab phantom 9 DIN ISO 1
11、2789-1:2013-01 National foreword This standard has been prepared by Technical Committee ISO/TC 85 “Nuclear energy”, Subcommittee SC 2 “Radiation protection” (Secretariat: AFNOR, France). The responsible German body involved in its preparation was the Normenausschuss Radiologie (Radiology Standards C
12、ommittee), Working Committee NA 080-00-01 AA Dosimetrie, in collaboration with the Deutsche Rntgengesellschaft (German Radiological Society), the Deutsche Gesellschaft fr Nuklearmedizin e. V. (DGN) (German Society of Nuclear Medicine), the Deutsche Gesellschaft fr Medizinische Physik e. V. (DGMP) (G
13、erman Society for Medical Physics) and the Deutsche Gesellschaft fr Radioonkologie e. V. (DEGRO) (German Society for Radio Oncology). The text of ISO 12789-1:2008 “Reference radiation fields Simulated workplace neutron fields Part 1: Characteristics and methods of production” has been adopted in thi
14、s standard without any modification. This first edition of ISO 12789-1 cancels and replaces ISO 12789:2000, of which it constitutes a minor revision. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. DIN shall not be held responsibl
15、e for identifying any or all such patent rights. DIN ISO 12789 consists of the following parts, under the general title Reference radiation fields Simulated workplace neutron fields: Part 1: Characteristics and methods of production Part 2: Calibration fundamentals related to the basic quantities Na
16、tional Annex NA (informative) Bibliography DIN 6802-1:1991-11, Neutron dosimetry Part 1: Special terms and definitions DIN 6814-2:2000-07, Terms in the field of radiological technique Part 2: Radiation physics DIN 6814-3:2001-01, Terms and definitions in the field of radiological technique Part 3: D
17、ose quantities and units 3 Introduction ISO 8529-1, ISO 8529-2 and ISO 8529-3, deal with the production, characterization and use of neutron fields for the calibration of personal dosimeters and area survey meters. These International Standards describe reference radiations with neutron energy spect
18、ra that are well defined and well suited for use in the calibration laboratory. However, the neutron spectra commonly encountered in routine radiation protection situations are, in many cases, quite different from those produced by the sources specified in the International Standards. Since personal
19、 neutron dosimeters, and to a lesser extent survey meters, are generally quite energy-dependent in their dose equivalent response, it might not be possible to achieve an appropriate calibration for a device that is used in a workplace where the neutron energy spectrum and angular distribution differ
20、 significantly from those of the reference radiation used for calibration. ISO 8529-1 describes four radionuclide-based neutron reference radiations in detail. This part of ISO 12789 includes the specification of neutron reference radiations that were developed to closely resemble radiation that is
21、encountered in practice. Specific examples of simulated workplace neutron source facilities are included in Annex A, for illustration. Reference radiation fields Simulated workplace neutron fields Part 1: Characteristics and methods of production 4 DIN ISO 12789-1:2013-01 1 Scope This part of ISO 12
22、789 gives guidance for producing and characterizing simulated workplace neutron fields that are to be used for calibrating neutron-measuring devices for radiation protection purposes. Both calculation and spectrometric measurement methods are discussed. Neutron energies in these reference fields ran
23、ge from approximately thermal neutron energies to several hundred GeV. The methods of production and the monitoring techniques for the various types of neutron fields are discussed, and the methods of evaluating and reporting uncertainties for these fields are also given. 2 Normative references The
24、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. ISO 8529-1:2001, Reference neutron radiations Part 1:
25、 Characteristics and methods of production ISO 8529-2:2000, Reference neutron radiations Part 2: Calibration fundamentals of radiation protection devices related to the basic quantities characterizing the radiation field ISO 8529-3:1998, Reference neutron radiations Part 3: Calibration of area and p
26、ersonal dosimeters and determination of response as a function of energy and angle of incidence ISO/IEC 98:1995, Guide to the expression of uncertainty in measurement (GUM) 3 Terms and definitions For the purpose of this document, the following terms and definitions apply. NOTE 1 The definitions fol
27、low the recommendations of ICRU Report 51 8and ICRU Report 33 4. NOTE 2 Multiples and submultiples of SI units are used throughout this part of ISO 12789. 3.1 neutron fluence dN divided by da, where dN is the number of neutrons incident on a sphere of cross-sectional area da: ddNa = NOTE The unit of
28、 the neutron fluence is metres raised to the negative 2 (m2). 5 N1) National footnote: The definitions also comply with DIN 6802-1:1991-11, DIN 6814-2:2000-07 and DIN 6814-3:2001-01. N1)3.2 neutron fluence rate d divided by dt, where d is the increment of neutron fluence in the time interval dt: 2dd
29、dddNtat = NOTE The unit of neutron fluence rate is metres raised to the negative 2 times seconds raised to the negative 2 (m2s1). DIN ISO 12789-1:2013-01 3.3 spectral distribution of the neutron fluence Ed divided by dE, where d is the increment of neutron fluence in the energy interval between E an
30、d E + dE: ddEE = NOTE The unit of the spectral distribution of the neutron fluence is metres raised to the negative 2 times reciprocal joules (m2J1). 3.4 ambient dose equivalent H*(d) at a point in a radiation field dose equivalent at a point in a radiation field that would be produced by the corres
31、ponding expanded and aligned field in the ICRU sphere at a depth, d, on the radius opposing the direction of the aligned field NOTE 1 For strongly penetrating radiation, a depth of 10 mm is currently recommended. NOTE 2 The unit of ambient dose equivalent is joules times reciprocal kilograms (Jkg1)
32、with the special name of sievert (Sv). 3.5 personal dose equivalent Hp(d) dose equivalent in soft tissue at an appropriate depth, d, below a specified point on the body NOTE 1 For strongly penetrating radiation, a depth of 10 mm is currently recommended. NOTE 2 The unit of personal dose equivalent i
33、s joules times reciprocal kilograms (Jkg1) with the special name of sievert (Sv). NOTE 3 ICRU Report 39 5defines the mass composition of soft tissue as: 76,2 % O; 10,1 % H; 11,1 % C; 2,6 % N. NOTE 4 In ICRU Report 47 7, the ICRU has considered the definition of the personal dose equivalent to includ
34、e the dose equivalent at a depth, d, in a phantom having the composition of ICRU tissue. Then, Hp(10) for the calibration of personal dosimeters is the dose equivalent at a depth of 10 mm in a phantom composed of ICRU tissue, but of the size and shape of the phantom used for calibration (a 30 cm 30
35、cm 15 cm parallelepiped). 3.6 neutron-fluence to dose-equivalent conversion coefficient hdose equivalent divided by neutron fluence Hh= NOTE 1 The unit of the neutron-fluence to dose-equivalent conversion coefficient is the sievert times square metres (Svm2). NOTE 2 Any statement of a fluence to dos
36、e-equivalent conversion coefficient requires the statement of the type of dose equivalent, e.g. ambient or personal dose equivalent. 6 N2)N2) National footnote: In Germany, the definition of DIN 6814-3:2001-01 applies. DIN ISO 12789-1:2013-01 4 Simulated workplace neutron fields The neutron fluence
37、spectra for a number of neutron fields have been available for some time 9, 10. Neutron fluence spectra, measured at workplaces and in simulated workplace calibration fields, are included in a catalogue resulting from work sponsored by the European Commission 11. This catalogue also contains respons
38、e functions for common detectors and dosimeters in addition to fluence to dose-equivalent conversion coefficients. Measurements in nuclear power plants 12-15in the vicinity of transport casks containing spent fuel elements 14, 15, and in factories producing radionuclide neutron sources 15, 16and rep
39、rocessing fuel elements 17have demonstrated that neutron energy spectra in such environments can be described as a superposition of the following components: a high-energy component representing the uncollided neutrons, a scattered component with an approximately 1/Endependence (where Enis the neutr
40、on energy), and a thermal-neutron component. For these types of spectra, the design of simulated workplace neutron fields requires a knowledge and consideration of the components mentioned above because the relative fractions of these components can be very different in different situations. Other r
41、adiation environments can contain neutrons having much higher energies. For example, neutrons with energies greater than 10 MeV, contributing 30 % to 50 % of the ambient dose equivalent and personal dose equivalent, have been found in the vicinity of high-energy particle accelerators 18, 19and in ai
42、rcraft flying at altitudes of 10 km to 15 km 20. Because of the characteristics of available neutron dosimeters and survey meters, it is difficult to obtain proper measurements in the workplace based on the calibration sources specified in ISO 8529-1 when the workplace spectrum differs markedly from
43、 the calibration source spectrum. This can result in an inaccurate estimate of the dose equivalent when such devices are used. At least two possibilities exist for improving the situation. First, the neutron spectrum of the workplace field can be measured, and a correction factor calculated to norma
44、lize the energy-dependent response of the detector. Secondly, a facility can be constructed to produce a neutron field that simulates the energy spectrum found in the workplace. When this field has been properly characterized, it can be used for the direct calibration of personal dosimeters and surv
45、ey meters. This latter approach has been employed at a number of laboratories, and this part of ISO 12789 gives guidance for producing and characterizing simulated workplace neutron spectra for the purpose of calibrating dosimeters and survey meters. The establishment of simulated workplace neutron
46、spectra in the calibration laboratory is necessary because the laboratory setting offers the possibility of controlling the most influential quantities. The environmental parameters, such as temperature and humidity, can be maintained at a constant level. The materials used in the construction of th
47、e various pieces of equipment can also be specified and controlled in the laboratory. The general layout as well as the sources of neutron scatter can also be controlled, or at least maintained constant, in the calibration laboratory. Simulated workplace neutron spectra that have been established in
48、 the calibration laboratory can be used to study the effects of changes in the neutron spectrum on the responses of personal dosimeters and survey meters. Dosimeter algorithms may also be tested with such sources used in conjunction with the other radionuclide sources recommended in ISO 8529-1. For these reasons, simulated workplace neutron fields should be provided for the investigation and calibration of neutron personal dosimete
