ASTM E720-04
(Guide)Standard Guide for Selection and Use of Neutron Sensors for Determining Neutron Spectra Employed in Radiation-Hardness Testing of Electronics
Standard Guide for Selection and Use of Neutron Sensors for Determining Neutron Spectra Employed in Radiation-Hardness Testing of Electronics
SCOPE
1.1 This guide covers the selection and use of neutron-activation detector materials to be employed in neutron spectra adjustment techniques used for radiation-hardness testing of electronic semiconductor devices. Sensors are described that have been used at many radiation hardness-testing facilities, and comments are offered in table footnotes concerning the appropriateness of each reaction as judged by its cross-section accuracy, ease of use as a sensor, and by past successful application. This guide also discusses the fluence-uniformity, neutron self-shielding, and fluence-depression corrections that need to be considered in choosing the sensor thickness, the sensor covers, and the sensor locations. These considerations are relevant for the determination of neutron spectra from assemblies such as TRIGA- and Godiva-type reactors and from Californium irradiators. This guide may also be applicable to other broad energy distribution sources up to 20 MeV.
Note 1—For definitions on terminology used in this guide, see Terminology E 170.
1.2 This guide also covers the measurement of the gamma-ray or beta-ray emission rates from the activation foils and other sensors as well as the calculation of the absolute specific activities of these foils. The principal measurement technique is high-resolution gamma-ray spectrometry. The activities are used in the determination of the energy-fluence spectrum of the neutron source. See Guide E 721.
1.3 Details of measurement and analysis are covered as follows:
1.3.1 Corrections involved in measuring the sensor activities include those for finite sensor size and thickness in the calibration of the gamma-ray detector, for pulse-height analyzer deadtime and pulse-pileup losses, and for background radioactivity.
1.3.2 The primary method for detector calibration that uses secondary standard gamma-ray emitting sources is considered in this guide and in General Methods E 181. In addition, an alternative method in which the sensors are activated in the known spectrum of a benchmark neutron field is discussed in Guide E 1018.
1.3.3 A data analysis method is presented which accounts for the following: detector efficiency; background subtraction; irradiation, waiting, and counting times; fission yields and gamma-ray branching ratios; and self-absorption of gamma rays and neutrons in the sensors.
1.4 The values stated in SI units are to be regarded as the standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:E720–04
Standard Guide for
Selection and Use of Neutron Sensors for Determining
Neutron Spectra Employed in Radiation-Hardness Testing of
1
Electronics
This standard is issued under the fixed designation E720; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 1.3.2 The primary method for detector calibration that uses
secondary standard gamma-ray emitting sources is considered
1.1 This guide covers the selection and use of neutron-
in this guide and in General Methods E181. In addition, an
activationdetectormaterialstobeemployedinneutronspectra
alternative method in which the sensors are activated in the
adjustment techniques used for radiation-hardness testing of
known spectrum of a benchmark neutron field is discussed in
electronic semiconductor devices. Sensors are described that
Guide E1018.
have been used at many radiation hardness-testing facilities,
1.3.3 A data analysis method is presented which accounts
and comments are offered in table footnotes concerning the
for the following: detector efficiency; background subtraction;
appropriateness of each reaction as judged by its cross-section
irradiation, waiting, and counting times; fission yields and
accuracy, ease of use as a sensor, and by past successful
gamma-ray branching ratios; and self-absorption of gamma
application. This guide also discusses the fluence-uniformity,
rays and neutrons in the sensors.
neutron self-shielding, and fluence-depression corrections that
1.4 The values stated in SI units are to be regarded as the
need to be considered in choosing the sensor thickness, the
standard.
sensor covers, and the sensor locations. These considerations
1.5 This standard does not purport to address all of the
are relevant for the determination of neutron spectra from
safety concerns, if any, associated with its use. It is the
assembliessuchasTRIGA-andGodiva-typereactorsandfrom
responsibility of the user of this standard to establish appro-
Californium irradiators. This guide may also be applicable to
priate safety and health practices and determine the applica-
other broad energy distribution sources up to 20 MeV.
bility of regulatory limitations prior to use.
NOTE 1—For definitions on terminology used in this guide, see Termi-
nology E170.
2. Referenced Documents
1.2 This guide also covers the measurement of the gamma-
2.1 General considerations of neutron-activation detectors
ray or beta-ray emission rates from the activation foils and
discussed in Practice E261, Test Method E262, and Guides
other sensors as well as the calculation of the absolute specific
E721 and E844 are applicable to this guide. Background
activities of these foils. The principal measurement technique
informationforapplyingthisguidearegivenintheseandother
is high-resolution gamma-ray spectrometry. The activities are
relevant standards as follows:
usedinthedeterminationoftheenergy-fluencespectrumofthe
2.2 ASTM Standards:
neutron source. See Guide E721.
E170 Terminology Relating to Radiation Measurements
2
1.3 Details of measurement and analysis are covered as
and Dosimetry
follows:
E181 Test Methods for Detector Calibration and Analysis
2
1.3.1 Corrections involved in measuring the sensor activi-
of Radionuclides
ties include those for finite sensor size and thickness in the
E261 Practice for Determining Neutron Fluence Rate, Flu-
2
calibration of the gamma-ray detector, for pulse-height ana-
ence, and Spectra by Radioactivation Techniques
lyzer deadtime and pulse-pileup losses, and for background
E262 Test Method for Determining Thermal Neutron Re-
2
radioactivity.
action and Fluence Rates by Radioactivation Techniques
E263 Test Method for Measuring Fast-Neutron Reaction
2
Rates by Radioactivation of Iron
1
This guide is under the jurisdiction of ASTM Committee E10 on Nuclear
Technology and Applications and is the direct responsibility of Subcommittee
E10.07 on Radiation Effects on Electronic Materials and Devices and Pulsed
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Radiation Effects.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
CurrenteditionapprovedJune1,2004.PublishedJuly2004.Originallyapproved
Standards volume information, refer to the standard’s Document Summary page on
in 1980. Last previous edition approved in 2002 E720–02.
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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