ISO 10647:1996

INTERNATIONAL
STANDARD 10647
First edition
1996-12-15
Procedures for calibrating and determining
the response of neutron-measuring devices
used for radiation protection purposes
Methodes d ‘6 talonnage et de dktermina tion de Ia r6ponse des
ins trumen ts de mesut-e des neutrons utilisb en radioprotection
Reference number
Page
Contents
Scope .
2 Normative references. . .
........................... 2
3 Devices covered in this International Standard
3.1 Individual dosemeters . .
........................ 2
3.2 Devices for surveying and area monitoring.
........... 2
4 Definitions . .
......................... 3
4.1 Metrological terms .
............................... 3
4.1.1 Reading .
................................... 3
4.1.2 Response .
.................................................... 3
4.1.3 Calibration factor
4.1.4 Energy dependence of response. . 3
4.1.5 Angular dependence of response . 3
4.1.6 Gamma-ray sensitivity .
4.1.7 Free-field quantities . .
4.2 Reference and monitoring instruments .
instrument . 3
4.2.1 Primary Standard
............................. 3
4.2.2 Secondary Standard instrument
............................ ................... 3
4.2.3 Transfer instrument
........................................... 3
4.2.4 Monitoring instrument
.......................................... ..................
4.3 Devices to be tested
Neutron dosemeter .
4.3.1
4.3.2 Neutron dose-ratemeter .
4.3.3 Neutron detector .
Symbols (sec annex G) .
...... 4
6 Traceability of the calibration of the reference radiation field
..................... 4
6.1 Traceability for radionuclide neutron sources.
0 ISO 1996
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hternational Organization for Standardization
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Printed in Switzerland
ii
@ ISO ISO 10647:1996(E)
............ 5
6.2 Traceability for neutron produced by an accelerator
................................. 5
6.3 Traceability for reactor neutron beams
7 Calibration principles for radionuclide neutron sources . 5
7.1 General principles . 5
............. 6
7.2 Important features of a neutron calibration facility.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.2.1 Source
Irradiation set-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.2.2
7.2.3 Irradiation room . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.3 Sources of scattered neutrons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.3.1 Room-scatter . . . . . . .0. 7
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.3.2 Air-attenuation (air-outscatter)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.3.3 Room-inscatter
Stattering from support structures . . . . . . . . . . . . . . . . . . . . . . . . 7
7.3.4
7.3.5 Spectral effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.4 Effective Point of measurement and effective calibration
distance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.1 Spherical devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.2 Cylindrical devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.3 Irradiation of individual dosemeters upon a
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Phantom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7.5 Effect of Photon radiation
8 Correcting for stattering effects for radionuclide neutron
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1 Initial measurements
.............................................. ..............
8.2 Geometry correction
......................................................... ........... 9
8.3 Analysis of data
8.3.1 Semi-empirical method . 9
8.3.2 Shadow-cone technique .
...... IO
8.3.3 Polynomial fit method .
IO
8.4 Choice of methods . .
............................ .............. IO
8.4.1 Semi-empirical method
............................................ IO
8.4.2 Shadow-cone method
Polynomial fit method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
8.4.3
............
9 Routine calibrations with radionuclide neutron sources.
9.1 Linearitiy determination .
....... 12
9.2 Determination of the angular dependence of response
................... 12
IO Estimated uncertainties .
10.1 Components of the uncertainty applicable to radionuclide
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Source calibrations
10.1.1 Uncertainty in neutron Source strength, B . . . . . . . . . . . . .

Uncertainty in anisotropy function, Fr(e) ~.~~~.O~.D.n
10.1.2
10.1.3 Uncertainty in calibration distance, k e . . . . . . . . . . . . . . . . . . . . . 12
10.1.4 Uncertainty in geometry-correction factor Fl(Z) . . . . . 12
10.1.5 Stattering correction uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
10.1.6 Statistical uncertainty in readings, hil . . . . . . . . . . . . . . . . . . . . . 13
10.1.7 Timing uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
10.1.8 Uncertainty in spectrum-averaged values of
fluence to-dose equivalent conversion . . . . . . . . . . . . . . . . . . 13
11 Calibrations using accelerators and reactors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*.*
11.2 Accelerator-produced neutrons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
11.2.1 Neutron f luence rate. . 14
11.2.2 Monitoring .
11.2.3 Energy dependence of response. .
11.2.4 Contaminant sources of neutrons . 14
11.2.5 Neutron energy and energy spread . 14
11.2.6 Variation of neutron spectrum with emission 14
angle . .
................................ 14
11.2.7 Target-scatter corrections.
............................. 15
11.2.8 Effects of neutron stattering
. . . . . . . . . . . . . . . . . . . 15
11.3 Reactor neutron beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.................................... 15
11.3.1 Filtered neutron beams.
11.3.2 Thermal neutrons . . 15
11.4 Estimated uncertainties for accelerator and reactors . . . . . . 15
11.4.1 Neutron energy and energy spread . 16
11.4.2 Variation of neutron spectrum with emission 16
angle . .
11.4.3 Target-scatter corrections. . 16
11.4.4 Effects of neutron stattering . 16
11.4.5 Fluence determination . 16
11.5 Combining uncertainties . .
Annexes
A Scheme of physical characteristics to be tested . . . . . . . . . . . . . . . . . . . . . . . . .
B Recommendations on Phantoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C Angular Source strength characteristics of two radionuclide
neutron sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D Minimum room length for 40% room return . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
E Air-attenuation correction factors and total air-scatter correction
F Criteria for construction and use of shadow cones . . . . . . . . . . . . . . . . . . . . .

@ ISO
G List of Symbols used in ISO 8529
................................................
H Bibliography
.................................................................................
Foreword
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. Esch member body interested in a subject for
which a technical 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 electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 10647 was prepared by Technical Committee
ISOPC 85, Nuclear energy, Subcommittee SC 2, Radiation protection.
Annexes A to F form an integral part of this International Standard.
Annexes G and H are for information only.
vi
INTERNATIONAL STANDARD 0 ISO
Procedures for calibrating and determining the response of
neutron-measuring devices used for radiation protection
purposes
1 Scope
This International Standard specifies procedures for the calibration of neutron-measuring devices used for radiation
protection purposes, and for determining their response as a function 0% energy, angle of incidence and dose
equivalent rate, using the neutron reference radiations specified in ISO 8529.
Since, according to ICRU Report 39 and ICRU Report 43, neutrons of all energies are strongly penetrating, area
monitors should be calibrated in terms of ambient dose equivalent [H*(lO)], and individual dosemeters should be
calibrated to measure individual dose equivalent, penetrating [Hp(lO)]. The procedures given in this International
Standard are, however, quite general, and may be used with any System of dose equivalent quantities. A
diagrammatic scheme of the physical characteristics to be tested is given as annex A.
2 Normative references
The following Standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All Standards are subject to
revision, and Parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the Standards indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
ISO 8529: 1989, Neutron reference radiations for calibrating neutron-measuring devices used for radiation
protection purposes and for determining their response as a function of neutron energy.
IEC 1005, 1990: Portable neutron ambient dose equivalent rate-meters for use in radiation protection.
ICRP Publication 21 (1973): Data for Protection Against lonizing Radiation from fxternal Sources. (Supplement to
ICRP Publication 15.)
ICRU Report 13 (1969): Neutron Fluence, Neutron Spectra and Kerma. International Commission on Radiation Units
and Measurements, Washington, D.C., USA.
ICRU Report 20 (1971): Radiation Protection lnstrumentation and its Application. International Commission an
Radiation Units and Measurements, Washington, D.C., USA.
ICRU Report 26 (1977): Neutron Dosimetry for Biology and Medicine. International Commission on Radiation Units
and Measurements, Washington, D.C., USA.
ICRU Report 33 (1980): Radiation Quantities and Units. International Commission on Radiation Units and
Measurements, Washington, D.C., USA.
1) ICRP: International Commission on Radiological Protection.

@ ISO
ICRU Report 39 (1985): Determination of Dose Equivaients ßesulting from fxternal ßadiat;on Sources. Internation
...