ISO/ASTM 51818:2013

Practice for dosimetry in an electron beam facility for radiation processing at energies between 80 and 300 keV

ISO/ASTM 51818:2013 covers dosimetric procedures to be followed in installation qualification, operational qualification and performance qualification (IQ, OQ, PQ), and routine processing at electron beam facilities to ensure that the product has been treated with an acceptable range of absorbed doses. Other procedures related to IQ, OQ, PQ, and routine product processing that may influence absorbed dose in the product are also discussed. The electron beam energy range covered in ISO/ASTM 51818:2013 is between 80 and 300 keV, generally referred to as low energy. Dosimetry is only one component of a total quality assurance program for an irradiation facility. Other measures may be required for specific applications such as medical device sterilization and food preservation. ISO/ASTM 51818:2013 is one of a set of standards that provides recommendations for properly implementing and utilizing dosimetry in radiation processing. It is intended to be read in conjunction with ASTM E2232.

Pratique de la dosimétrie dans une installation de traitement par irradiation utilisant un faisceau d'électrons d'énergies comprises entre 80 et 300 keV

General Information

• Status: Withdrawn
• Publication Date: 14-May-2013
• Withdrawal Date: 14-May-2013
• ICS: 17.240 - Radiation measurements
• Technical Committee: ISO/TC 85 - Nuclear energy, nuclear technologies, and radiological protection
• Drafting Committee: ISO/TC 85 - Nuclear energy, nuclear technologies, and radiological protection
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 30-Jun-2020

Relations

• Revised: ISO/ASTM 51818:2020 - Practice for dosimetry in an electron beam facility for radiation processing at energies between 80 and 300 keV
• Effective Date: 23-Apr-2020
• Revises: ISO/ASTM 51818:2009 - Practice for dosimetry in an electron beam facility for radiation processing at energies between 80 and 300 keV
• Effective Date: 20-Oct-2012
• Consolidated By: ISO/ASTM 52903-2:2020 - Additive manufacturing — Material extrusion-based additive manufacturing of plastic materials — Part 2: Process equipment
• Effective Date: 06-Jun-2022

Standards Content (Sample)

INTERNATIONAL ISO/ASTM
STANDARD 51818
Thirdedition
2013-06-01
Practice for dosimetry in an electron
beam facility for radiation processing at
energies between 80 and 300 keV
Pratique de la dosimétrie dans une installiation de traitement par
irradiation utilisant un faisceau d’électrons d’énergies comprises
entre 80 keV et 300 keV
Referencenumber
ISO/ASTM51818:2013(E)
©ISO/ASTMInternational2013

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ISO/ASTM 51818:2013(E)
©ISO/ASTMInternational2013
Allrightsreserved.Unlessotherwisespecified nopartofthispublicationmaybereproducedorutilizedinanyformorbyanymeans,electronicormechanical,
including photocopying and microfilm without permission in writing from either ISO at the address below or ISO’s member body in the country of the
requester.IntheUnitedStates,suchrequestsshouldbesenttoASTMInternational.
ISOcopyrightoffice ASTMInternational,100BarrHarborDrive,POBoxC700,
Casepostale56•CH-1211Geneva20 WestConshohocken,PA19428-2959,USA
Tel.[phone] Tel.[phone]
Fax[phone] Fax[phone]
[e-mail] [e-mail]
Webwww.iso.org Webwww.astm.org
PublishedinSwitzerland
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ISO/ASTM 51818:2013(E)
Contents Page
1 Scope . 1
2 Referenceddocuments . 1
3 Terminology . 2
4 Significanc anduse . 2
5 Selectionandcalibrationofthedosimetrysystem . 3
6 Installationandoperationalqualificatio . 3
7 Performancequalificatio . 4
8 Routineprocesscontrol . 4
9 Measurementuncertainty . 4
10 Documentation . 5
11 Keywords . 5
Annexes . 5
Bibliography . 13
Figure A1.1 Exampleofmeasurementofdoseasfunctionofaveragebeamcurrent I,conveying
speed Vandbeamwidth W .Measuredatanelectronacceleratorwithbeamenergy110keV.
b
2
K=216.57(kGy·m )/(A·s) . 6
Figure A1.2 Exampleofbeamwidthmeasurement(3measurementsandtheiraverageare
shown).Beamwidthwasmeasuredonalowenergyacceleratorinstalledinanelectronbeam
tunnelforanasepticfillin line (6) . 6
Figure A1.3 Exampleofbeamwidthmeasurementatalow-energyelectronacceleratorfacilityfor
curingpurpose . 7
-3
Figure A1.4 Calculateddepth-dosedistributioninwater(specifi density1gcm ) . 8
-3
Figure A1.5 Calculateddepth-dosedistributioninwater(specifi density1gcm ) . 9
Figure A1.6 Methodsformeasurementofdepthdosedistribution . 9
Figure A1.7 Examplesofmeasurementsofdepthdosedistributionsatthesameelectronbeam
facility,butatdifferentbeamenergies . 10
Figure A2.1 Averagedosemeasuredwiththreedosimeters(18µmRCDfil dosimeter;50µm
RCDfil dosimeter;130µmalaninefil dosimeter)allcalibratedbyirradiationata10MeV
electronaccelerator,andnowirradiatedata125keVelectronaccelerator.Depthdosedistribution
measuredatRisøHDRL125keVelectronaccelerator. . 10
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ISO/ASTM 51818:2013(E)
Foreword
ISO(theInternationalOrganizationforStandardization)isaworldwidefederationofnationalstandardsbodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technicalcommittees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehasbeen
establishedhastherighttoberepresentedonthatcommittee.Internationalorganizations,governmentaland
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
InternationalElectrotechnicalCommission(IEC)onallmattersofelectrotechnicalstandardization.
DraftInternationalStandardsadoptedbythetechnicalcommitteesarecirculatedtothememberbodiesfor
voting. Publication as an International Standard requires approval by at least 75% of the member bodies
castingavote.
ASTMInternationalisoneoftheworld’slargestvoluntarystandardsdevelopmentorganizationswithglobal
participation from affected stakeholders.ASTM technical committees follow rigorous due process balloting
procedures.
Apilot project between ISO andASTM International has been formed to develop and maintain a group of
ISO/ASTM radiation processing dosimetry standards. Under this pilot project, ASTM Committee E61,
RadiationProcessing,isresponsibleforthedevelopmentandmaintenanceofthesedosimetrystandardswith
unrestrictedparticipationandinputfromappropriateISOmemberbodies.
Attentionisdrawntothepossibilitythatsomeoftheelementsofthisdocumentmaybethesubjectofpatent
rights. Neither ISO norASTM International shall be held responsible for identifying any or all such patent
rights.
International Standard ISO/ASTM 51818 was developed byASTM Committee E61, Radiation Processing,
through Subcommittee E61.03, Dosimetry Application, and by Technical Committee ISO/TC 85, Nuclear
energy,nucleartechnologiesandradiologicalprotection.
This third edition cancels and replaces the second edition (ISO/ASTM 51818:2009), which has been
technicallyrevised.
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ISO/ASTM 51818:2013(E)
Standard Practice for
Dosimetry in an Electron Beam Facility for Radiation
1
Processing at Energies Between 80 and 300 keV
This standard is issued under the fixed designation ISO/ASTM 51818; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision.
1. Scope 2. Referenced documents
2
1.1 This practice covers dosimetric procedures to be fol- 2.1 ASTM Standards:
lowedininstallationqualification,operationalqualificationand E170 TerminologyRelatingtoRadiationMeasurementsand
performance qualification (IQ, OQ, PQ), and routine process- Dosimetry
ing at electron beam facilities to ensure that the product has E2232 Guide for Selection and Use of Mathematical Meth-
been treated with an acceptable range of absorbed doses. Other odsforCalculatingAbsorbedDoseinRadiationProcessing
procedures related to IQ, OQ, PQ, and routine product pro- Applications
cessing that may influence absorbed dose in the product are E2303 Guide for Absorbed-Dose Mapping in Radiation
also discussed. Processing Facilities
1.2 The electron beam energy range covered in this practice E2628 Practice for Dosimetry in Radiation Processing
isbetween80and300keV,generallyreferredtoaslowenergy. E2701 Guide for Performance Characterization of Dosim-
1.3 Dosimetry is only one component of a total quality eters and Dosimetry Systems for Use in Radiation Process-
assurance program for an irradiation facility. Other measures ing
may be required for specific applications such as medical F1355 Guide for Irradiation of Fresh Agricultural Produce
device sterilization and food preservation. as a Phytosanitary Treatment
1.4 Other specific ISO and ASTM standards exist for the F1356 Practice for Irradiation of Fresh and Frozen Red
irradiation of food and the radiation sterilization of health care Meat and Poultry to Control Pathogens and Other Micro-
products. For the radiation sterilization of health care products, organisms
3
see ISO 11137. In those areas covered by ISO 11137, that 2.2 ISO Standards:
standard takes precedence. For food irradiation, see ISO 11137-1:2006 Sterilization of health care products–Radia-
14470:2011. Information about effective or regulatory dose tion–Part 1: Requirements for development, validation
limits for food products is not within the scope of this practice and routine control of a sterilization process for medical
(see ASTM F1355 and F1356). devices
1.5 This document is one of a set of standards that provides 14470:2011 Food irradiation–Requirements for the devel-
recommendations for properly implementing and utilizing opment, validation and routine control of the ionizing
dosimetry in radiation processing. It is intended to be read in radiation used for the treatment of food
conjunction with ASTM E2232, “Practice for Dosimetry in 17025:2005 General requirements for the competence of
Radiation Processing”. testing and calibration laboratories
2
1.6 This standard does not purport to address all of the 2.3 ISO/ASTM Standards:
safety concerns, if any, associated with its use. It is the 51261 Practice for Calibration of Routine Dosimetry Sys-
responsibility of the user of this standard to establish appro- tems for Radiation Processing
priate safety and health practices and determine the applica- 51275 Practice for Use of a Radiochromic Film Dosimetry
bility of regulatory limitations prior to use. System
51607 Practice for Use of an Alanine-EPR Dosimetry Sys-
tem
51649 Practice for Dosimetry in an Electron Beam Facility
1
This practice is under the jurisdiction of ASTM Committee E61 on Radiation
Processing and is the direct responsibility of Subcommittee E61.03 on Dosimetry
Application, and is also under the jurisdiction of ISO/TC 85/WG 3.
2
Current edition approved April 9, 2013. Published June 2013. Originally For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ϵ1
published as ASTM E1818–96. Last previous ASTM edition E1818–96 . ASTM contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
ϵ1
E1818–96 was adopted in 1998 with the intermediate designation ISO Standards volume information, refer to the standard’s Document Summary page on
15573:1998(E). The present Third Edition of International Standard ISO/ASTM the ASTM website.
3
51818:2013(E) is a major revision of the Second Edition of ISO/ASTM Available from International Organization for Standardization (ISO), 1, ch. de
51818:2009(E). la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.
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ISO/ASTM 51818:2013(E)
forRadiationProcessingatEnergiesbetween300keVand that could reasonably be attributed to the measurand or derived
25 MeV quantity (see ISO/ASTM Guide 51707).
51650 Practice for Use of a Cellulose Triacetate Dosimetry 3.2 Definitions of Terms Specific to This Standard:
System 3.2.1 D —absorbed dose to water in the first micrometer of
µ
5
51707 Guide for Estimating Uncertainties in Dosimetry for water equivalent absorbing material (1).
Radiation Processing 3.2.1.1 Discussion—D is a term used by an approved
µ
2.4 International Commission on Radiation Units and laboratory to specify reported surface dose values of transfer
4
Measurements (ICRU) Report: standard dosimeters based on adjustments made to account for
ICRU Report 85a Fundamental Quantities and Units for user site specific calibration irradiation conditions.
Ionizing Radiation 3.2.2 linear process rate—product length irradiated per unit
ICRU Report 80 Dosimetry Systems for Use in Radiation time to deliver a given dose.
Processing 3.2.3 mass process rate—product mass irradiated per unit
time to deliver a given dose.
3. Terminology
3.2.4 area process rate—product area irradiated per unit
3.1 Definitions: time to deliver a given dose.
3.1.1 absorbed dose (D)—quantity of ionizing radiation 3.3 Definitions of other terms used in this standard that
energy imparted per unit mass of a specified material. The SI pertain to radiation measurement and dosimetry may be found
unit of absorbed dose is the gray (Gy), where 1 gray is
in Terminology E170. Definitions in Terminology E170 are
equivalent to the absorption of 1 joule per kilogram of the compatible with ICRU Report 85a; that document, therefore,
specified material (1 Gy = 1 J/kg). The mathematical relation-
may be used as an alternative reference.
– –
ship is the quotient of d´ by dm, where d´ is the mean
4. Significance and use
incremental energy imparted by ionizing radiation to matter of
4.1 A variety of irradiation processes uses low energy
incremental mass dm.
electron beam facilities to modify product characteristics.
3.1.1.1 Discussion—Throughout this practice, “absorbed
Dosimetry requirements, the number and frequency of mea-
dose” is referred to as “dose”.
surements, and record keeping requirements will vary depend-
3.1.2 approved laboratory—laboratory that is a recognized
ing on the type and end use of the products being processed.
national metrology institute; or has been formally accredited to
Dosimetry is often used in conjunction with physical, chemi-
ISO/IEC 17025; or has a quality system consistent with the
cal, or biological testing of the product, to help verify specific
requirements of ISO/IEC 17025.
treatment parameters.
3.1.3 average beam current—time-averaged electron beam
current.
NOTE 1—In many cases dosimetry results can be related to other
3.1.4 beam width—dimension of the irradiation zone per-
quantitative product properties; for example, gel fraction, melt flow,
pendicular to the direction of product movement, at a specified
modulus, molecular weight distribution, or cure analysis tests.
distance from the accelerator window.
4.2 Radiation processing specifications usually include a
3.1.5 depth-dose distribution—variation of absorbed dose
minimum or maximum absorbed dose limit, or both. For a
with depth from the incident surface of a material exposed to
given application these limits may be set by government
a given radiation.
regulation or by limits inherent to the product itself.
3.1.6 dosimeter—device that, when irradiated, exhibits a
4.3 Critical process parameters must be controlled to obtain
quantifiable change that can be related to absorbed dose in a
reproducible dose distribution in processed materials. The
given material using appropriate measurement instruments and
electron beam energy, beam current, beam width and process
procedures.
line speed (conveying speed) affect absorbed dose.
3.1.7 dosimetry system—system used for determining ab-
4.4 Before any electron beam facility can be routinely
sorbed dose, consisting of dosimeters, measurement instru-
utilized, it must be validated to determine its effectiveness.
ments and their associated reference standards, and procedures
This involves testing of the process equipment, calibrating the
for the system’s use.
measuring instruments and the dosimetry system, and demon-
3.1.8 electron beam energy—kinetic energy of the acceler-
strating the ability to consistently deliver the required dose
ated electrons in the beam.
within predetermined specifications.
3.1.9 traceability—property of the result of a measurement
4.5 In order for a dosimetry system to be effective in
or the value of a standard whereby it can be related to stated
low-energy electron irradiation applications and to measure
references, usually national or international standards, through
doses with an acceptable level of uncertainty, it is necessary to
an unbroken chain of comparisons all having stated uncertain-
calibratethedosimetrysystemunderirradiationconditionsthat
ties.
are consistent with those encountered in routine use. For
3.1.10 uncertainty—parameter associated with the result of
example, a dosimetry system calibration conducted using
a measurement that characterizes the dispersion of the values
4 5
Available from the International Commission on Radiation Units and Measure- The boldface numbers in parentheses refer to the bibliography at the end of this
ments, 7910 Woodmont Ave., Suite 800, Bethesda, MD 20814, U.S.A. standard.
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ISO/ASTM 51818:2013(E)
penetrating gamma radiation or high energy electrons may 6. Installation and operational qualification
result in significantly inaccurate dose measurement when the
6.1 Installation qualification (IQ) is carried out to demon-
dosimetry system is used at low energy electron beam facili-
strate that the irradiation equipment and any ancillary items
ties. Details of calibration are discussed in Section 5.
have been supplied and installed in accordance with their
specifications.
5. Selection and calibration of the dosimetry system
NOTE 4—ThedosimetricmeasurementscarriedoutduringIQwilloften
5.1 Selection of Dosimetry Systems:
bethesameastheonescarriedoutduringOperationalQualification(OQ).
5.1.1 ASTM E2628 identifies requirements for selection of IQ typically involves the use of dosimetric measurements of beam
penetration and dose uniformity that can be used to calculate estimates of
dosimetry systems. For use with low-energy electron beam
process throughput to verify the equipment performance specifications.A
facilities consideration should specifically be given to the
dosimetry system calibration curve obtained by dosimeter irradiation at
limited range of such electrons which might give rise to dose
another facility might be used for these dose measurements, but in order
gradients through the thickness of the dosimeter. By choosing
to ensure that the dose measurements are traceable to national standards,
thin film dosimeters this problem can be limited (see Note 2)
the calibration curve must be verified for the actual conditions of use.
(1).
6.2 Operational qualification (OQ) is carried out to charac-
5.1.2 When selecting a dosimetry system, consideration
terize the performance of the irradiation equipment with
should be given to effects of influence quantities on the
respect to reproducibility of dose to product. For OQ product
response of the dosimeter (see E2701). One such influence
dose mapping guidance, see ASTM E2303.
quantity is irradiation atmosphere, and some low-energy accel-
erator applications involve irradiation in oxygen-free condi- NOTE 5—Some applications may not require OQ dose measurements to
be traceable to a national standard (see Annex A4).
tions.
NOTE 6—Dose measurements for OQ may have to be carried out using
5.2 Calibration of the Dosimetry System:
a dosimetry system calibration curve obtained by irradiation at another
5.2.1 The dosimetry system shall be calibrated prior to use
facility. This calibration curve should be verified as soon as possible, and
and at intervals thereafter in accordance with the user’s
corrections applied to the OQ dose measurements as needed.
documented procedure that specifies details of the calibration
6.2.1 The performance of the low-energy electron beam
process and quality assurance requirements. Calibration meth-
facilitydependsontheenergyoftheelectrons.Itmaytherefore
ods are given in ISO/ASTM 51261.
be necessary to carry out separate OQ measurements for each
5.2.2 The calibration irradiation may be performed by
energy selected for the operation of the facility.
irradiating the dosimeters at (a) an approved laboratory or (b)
6.2.2 The relevant dosimetric OQ measurements are de-
a production irradiator under actual production irradiation
scribed in more detail inAnnexA1. They typically include the
conditions together with transfer standard dosimeters issued
following:
and analyzed by an approved laboratory. In case of option (a),
6.2.2.1 Dose as Function of Average Beam Current, Beam
the resulting calibration curve shall be verified for the actual
Width and Conveying Speed—Dose to the product irradiated in
conditions of use (see ISO/ASTM 51261). The same applies
an electron beam facility is proportional to average beam
for option (b) if irradiation conditions different from the actual
current (I), inversely proportional to conveying speed (V), and
production conditions have been used for the calibration
inversely proportional to beam width (W ). The last relation-
b
irradiation.
ship is valid for product that is conveyed through the beam
NOTE 2—While 5.2.2 is valid for most dosimeter calibration irradia-
zone perpendicular to the beam width. This is expressed as:
tions, it must be recognized that the irradiation of various dosimeters with
Dose 5 ~K · I!/ ~V · W ! (1)
b
low energy electrons (less than 300 keV) may lead to dose gradients
through the thickness of the dosimeter. When the dosimeter response is
where:
measured, this will lead to an apparent dose that is related to the dose
D = absorbed dose (Gy),
distribution. For a given set of irradiation conditions, the apparent dose
I = average beam current (A),
will depend on the thickness of the dosimeter, i.e., dosimeters with
-1
V = conveying speed (m s ),
different thickness will measure different apparent doses. One solution to
W = beam width (m), and
overcome this problem is that all dose measurements are specified as dose b
K = slope of the straight line relationship in Eq 1
to water in the first micrometer of the absorbing material.This is given the
2
symbol D and is independent of the dosimeter thickness (1). The dose (Gy·m)/(A·s).
µ
estimate for the calibration is carried out by the approved laboratory that
This straight-line relationship shall be determined for each
issues the transfer standard dosimeters (5.2.2), and this dose can be given
energy selected for the operation of the facility. In order to
in terms of D (see Annex A2).
µ
determine the relationship, dose shall be measured at a specific
NOTE 3—Some applications may not require dose measurements to be
location using a number of selected parameter sets of beam
traceable to a national standard (see Annex A4).
current, conveying speed and beam width to cover the operat-
5.3 Measurement Instrument Calibration and Performance ing range of the facility.
Verification—For the calibration of the instruments, and for the 6.2.2.2 Beam Width—The beam width is measured by
verification of instrument performance between calibrations, placing dosimeter strips or discrete dosimeters at selected
ISO/ASTM 51261, the corresponding ISO/ASTM or ASTM intervals over the full beam width. Whenever possible dosim-
standard for the dosimetry system, and/or instrument-specific eters should be placed beyond the expected beam width to
operating manuals should be consulted. identify the limits of the full beam width.
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ISO/ASTM 51818:2013(E)
NOTE 9—Dose mapping exercises do not have to be carried out at the
6.2.2.3 Beam Penetration—The beam penetration is mea-
same dose as used for product irradiations. The use of higher doses, for
suredusingastackofthindosimetersorbyplacingadosimeter
example, can enable the dosimetry system to be used in a more accurate
strip under thin layers of plastic foils.
part of its operating range, thereby improving the overall accuracy of the
(1) Calculation Methods—Beam penetration can be calcu-
dose mapping.
lated using mathematical modeling (see ASTM E2232).
NOTE 10—Some applications may not require PQ dose measurements
6.2.2.4 DoseDistributiononReferenceMaterial—Itmaybe
to be traceable to a national standard (see Annex A4).
needed to measure the distribution of dose on or in a reference
7.3 OQ dose mapping can in some cases be used as PQ dose
material.
mapping. For example, this is the case for irradiation treatment
6.2.2.5 Process Interruption—Aprocess interruption can be
of wide webs of infinite length. In other cases, such as
caused by, for example, failure of beam current delivery or by
sterilizationofcomplexproduct,itmayberequiredtocarryout
the conveyor stopping. The effect of a process interruption
specific PQ product dose mapping.
shall be determined, so that decisions about possible product
7.4 During PQ dose mapping the locations and magnitudes
disposition can be made.
of minimum and maximum doses, as well as the dose at a
6.2.3 The measurements in 6.2.2 shall be repeated a suffi-
routine monitoring position are determined.
cientnumberoftimes(threeormore)toallowdeterminationof
7.5 The relationship between minimum and maximum
the operating parameter variability based on a statistical
doses and the dose at a routine monitoring position is deter-
evaluation of the dose measurements.
mined.
NOTE 7—The operating parameter variability can be determined from 7.6 PQ dose mapping measurements shall be repeated a
the scatter between repeated dose measurements made at different times
sufficient number of times (three or more) to allow statistical
using identical operating parameter settings. Determination of this vari-
evaluation and characterization of the dose distribution data.
ability forms part of operational qualification. Operating parameter
7.7 Based on the measured uncertainties of this relationship
variabilitycontributestouncertaintyofmeasureddoses.Itisoftendifficult
(see 7.5) acceptable limits for variation of the dose at the
to separate operating parameter variability and dosimeter reproducibility
routine monitoring position to be measured during process
and the variability determined will often be a combination of the two (2).
irradiations can be determined (2).
6.2.4 Based on the measured variability of the operating
7.8 Repeat of PQ dose mapping shall be considered if
parameters, limits for their acceptable variation can be deter-
product is changed (thus affecting dose or dose distribution), or
mined.
if the OQ status of the irradiation facility is changed.
6.2.5 Requalification—OQ measurements shall be repeated
at intervals specified by the user’s documented procedure. The
8. Routine process control
intervalsshallbechosentoprovideassurancethattheirradiator
8.1 Monitoring of Operating Parameters—The operating
is consistently operating within specifications. Requalification
parameters (beam energy, beam current, beam width and
is typically carried out on an annual cycle, with specific parts
conveying speed) shall be monitored and recorded continu-
of requalification at shorter time intervals within this cycle. If
ously during the process or at intervals specified by the
requalification measurements show that the OQ status of the
operator of the facility.The intervals shall be chosen to provide
irradiator has changed, then PQ might have to be repeated.
assurance that the irradiator is consistently operating within
6.2.6 OQ measurements shall be repeated after assessment
specifications.
of changes of the irradiation facility that might affect dose or
dose distribution. The extent to which requalification is carried NOTE 11—Beam energy, beam current and beam width are usually not
measured directly, but are obtained through indirect measurements.
out shall be justified.
8.2 Measurement of Routine Dose—The dose at the routine
NOTE 8—Activities that might affect the OQ status of the irradiation
monitoring position shall be measured at intervals specified by
facility include, but are not limited to:
the operator of the facility. The intervals shall be chosen to
replacementofacceleratoremitter
replacementofacceleratorwindow
verify the irradiator operated within limits, and thereby ensur-
replacementofwindowsupportgrid
ing that the product specifications were achieved.
replacementofconveyorparts
changeinelectronenergy
NOTE 12—Some applications may not require routine dose measure-
changeindistanceofacceleratorwindowtoproductsurface
ments to be traceable to a national standard (see Annex A4).
7. Performance qualification
8.3 Process Control Limits—Acceptance limits for the
variation of the monitored process parameters (8.1) and mea-
7.1 Performance Qualification (PQ) is the stage of valida-
sured routine dose (8.2) should be selected based on the
tion which uses defined product to demonstrate that the facility
measured uncertainties (see 6.2.3 and 7.6). The selection of
consistently operates in accordance with predetermined criteria
acceptance limits can be based on the principles for statistical
to deliver specified doses, thereby resulting in product that
process control (2).
meets the specified requirements.
7.2 PQ dose mapping is carried out to demonstrate that
9. Measurement uncertainty
minimum dose to product exceeds the dose required for the
9.1 All dose measurements shall be accompanied by an
intended effect and that maximum dose to product does not
exceed a maximum acceptable dose. For PQ product dose estimate of uncertainty. Appropriate procedures are recom-
mapping guidance, see ASTM E2303. mended in ISO/ASTM Guide 51707 (see also (3)).
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ISO/ASTM 51818:2013(E)
9.2 All components of uncertainty should be included in the 10.1.1 Data from initial IQ and from any changes to the
estimate, including those arising from calibration, do
...