ASTM E1250-10
(Test Method)Standard Test Method for Application of Ionization Chambers to Assess the Low Energy Gamma Component of Cobalt-60 Irradiators Used in Radiation-Hardness Testing of Silicon Electronic Devices
Standard Test Method for Application of Ionization Chambers to Assess the Low Energy Gamma Component of Cobalt-60 Irradiators Used in Radiation-Hardness Testing of Silicon Electronic Devices
SIGNIFICANCE AND USE
Although Co-60 nuclei only emit monoenergetic gamma rays at 1.17 and 1.33 MeV, the finite thickness of sources, and encapsulation materials and other surrounding structures that are inevitably present in irradiators can contribute a substantial amount of low-energy gamma radiation, principally by Compton scattering (1, 2). In radiation-hardness testing of electronic devices this low-energy photon component of the gamma spectrum can introduce significant dosimetry errors for a device under test since the equilibrium absorbed dose as measured by a dosimeter can be quite different from the absorbed dose deposited in the device under test because of absorbed dose enhancement effects (3, 4). Absorbed dose enhancement effects refer to the deviations from equilibrium absorbed dose caused by non-equilibrium electron transport near boundaries between dissimilar materials.
The ionization chamber technique described in this method provides an easy means for estimating the importance of the low-energy photon component of any given irradiator type and configuration.
When there is an appreciable low-energy spectral component present in a particular irradiator configuration, special experimental techniques should be used to ensure that dosimetry measurements adequately represent the absorbed dose in the device under test. (See Practice E1249.)
SCOPE
1.1 Low energy components in the photon energy spectrum of Co-60 irradiators lead to absorbed dose enhancement effects in the radiation-hardness testing of silicon electronic devices. These low energy components may lead to errors in determining the absorbed dose in a specific device under test. This method covers procedures for the use of a specialized ionization chamber to determine a figure of merit for the relative importance of such effects. It also gives the design and instructions for assembling this chamber.
1.2 This method is applicable to measurements in Co-60 radiation fields where the range of exposure rates is 7 × 10 −6 to 3 × 10−2 C kg −1 s−1 (approximately 100 R/h to 100 R/s). For guidance in applying this method to radiation fields where the exposure rate is >100 R/s, see Appendix X1.
Note 1—See Terminology E170 for definition of exposure and its units.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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: E1250 − 10
StandardTest Method for
Application of Ionization Chambers to Assess the Low
Energy Gamma Component of Cobalt-60 Irradiators Used in
1
Radiation-Hardness Testing of Silicon Electronic Devices
This standard is issued under the fixed designation E1250; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope Dosimetry (TLD) Systems for Determining Absorbed
DoseinRadiation-HardnessTestingofElectronicDevices
1.1 Low energy components in the photon energy spectrum
E1249Practice for Minimizing Dosimetry Errors in Radia-
ofCo-60irradiatorsleadtoabsorbeddoseenhancementeffects
tionHardnessTestingofSiliconElectronicDevicesUsing
in the radiation-hardness testing of silicon electronic devices.
Co-60 Sources
These low energy components may lead to errors in determin-
ing the absorbed dose in a specific device under test. This
3. Terminology
method covers procedures for the use of a specialized ioniza-
tion chamber to determine a figure of merit for the relative
3.1 absorbed dose, D—quotientof dε¯ by dm,where dε¯ isthe
importance of such effects. It also gives the design and
mean energy imparted by ionizing radiation to the matter in a
instructions for assembling this chamber.
volume element and dm is the mass of matter in that volume
element.
1.2 This method is applicable to measurements in Co-60
−6
radiation fields where the range of exposure rates is 7×10
D 5 dε¯/dm (1)
−2 −1 −1
to3×10 Ckg s (approximately100R/hto100R/s).For
3.2 absorbed dose enhancement factor— ratio of the ab-
guidance in applying this method to radiation fields where the
sorbed dose at a point in a material of interest to the
exposure rate is >100 R/s, see Appendix X1.
equilibrium absorbed dose in that same material.
NOTE1—SeeTerminologyE170fordefinitionofexposureanditsunits.
3.3 average absorbed dose—mass-weighted mean of the
1.3 The values stated in SI units are to be regarded as the
absorbed dose over a region of interest.
standard. The values given in parentheses are for information
3.4 average absorbed dose enhancement factor—ratio of
only.
the average absorbed dose in a region of interest to the
1.4 This standard does not purport to address all of the
equilibrium absorbed dose.
safety concerns, if any, associated with its use. It is the
3.5 dosimeter—any device used to determine the equilib-
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- rium absorbed dose in the material and at the irradiation
position of interest. Examples of such devices include ther-
bility of regulatory limitations prior to use.
moluminescence dosimeters (TLDs), liquid chemical
2. Referenced Documents
dosimeters, and radiochromic dye films. (See Practice E668,
2
for a discussion of TLDs.)
2.1 ASTM Standards:
E170Terminology Relating to Radiation Measurements and
3.6 equilibrium absorbed dose—absorbed dose at some
Dosimetry
incremental volume within the material in which the condition
E668 Practice for Application of Thermoluminescence-
of charged particle equilibrium (the energies, number, and
direction of charged particles induced by the radiation are
constant throughout the volume) exists. (See Terminology
1
This method is under the jurisdiction of ASTM Committee E10 on Nuclear
E170.)
Technology and Applicationsand is the direct responsibility of Subcommittee
E10.07 on Radiation Dosimetry for Radiation Effects on Materials and Devices.
Current edition approved Dec. 1, 2010. Published January 2011. Originally
4. Significance and Use
approved in 1988. Last previous approved in 2005 as E1250-88(2005). DOI:
10.1520/E1250-10.
4.1 AlthoughCo-60nucleionlyemitmonoenergeticgamma
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
rays at 1.17 and 1.33 MeV, the finite thickness of sources, and
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
encapsulation materials and other surrounding structures that
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. areinevitablypresentinirradiatorscancontributeasubstantial
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E1250 − 10
physical dimensions (all dimensions given in inches):
Nominal outer diameter 0.242
Conductor spacing (center to center) 0.076
Conductor dielectric outer diameter 0.076
Conductor diameter 0.037
Other equivalent twinaxial cable types can be used, but the applicable
dimensionsoftheionizationchamberbod
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:E1250–88(Reapproved 2005) Designation: E1250 – 10
Standard Test Method for
Application of Ionization Chambers to Assess the Low
Energy Gamma Component of Cobalt-60 Irradiators Used in
1
Radiation-Hardness Testing of Silicon Electronic Devices
This standard is issued under the fixed designation E1250; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 Low energy components in the photon energy spectrum of Co-60 irradiators lead to absorbed dose enhancement effects in
the radiation-hardness testing of silicon electronic devices. These low energy components may lead to errors in determining the
absorbed dose in a specific device under test. This method covers procedures for the use of a specialized ionization chamber to
determine a figure of merit for the relative importance of such effects. It also gives the design and instructions for assembling this
chamber.
−6
1.2 This method is applicable to measurements in Co-60 radiation fields where the range of exposure rates is 7 310 to
−2 −1 −1
3 310 Ckg s (approximately 100 R/h to 100 R/s). For guidance in applying this method to radiation fields where the
exposure rate is >100 R/s, see Appendix X1.
NOTE 1—See Terminology E170 for definition of exposure and its units.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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.
2. Referenced Documents
2
2.1 ASTM Standards:
E170 Terminology Relating to Radiation Measurements and Dosimetry
E668 Practice for Application of Thermoluminescence-Dosimetry (TLD) Systems for Determining Absorbed Dose in
Radiation-Hardness Testing of Electronic Devices
E1249 Practice for Minimizing Dosimetry Errors in Radiation Hardness Testing of Silicon Electronic Devices Using Co-60
Sources
3. Terminology
3.1 absorbed dose, D—quotient of d ´¯by dm, where d ´¯ is the mean energy imparted by ionizing radiation to the matter in a
volume element and dm is the mass of matter in that volume element.
D 5 d´¯/dm (1)
3.2 absorbed dose enhancement factor— ratio of the absorbed dose at a point in a material of interest to the equilibrium
absorbed dose in that same material.
3.3 average absorbed dose—mass-weighted mean of the absorbed dose over a region of interest.
3.4 average absorbed dose enhancement factor—ratio of the average absorbed dose in a region of interest to the equilibrium
absorbed dose.
3.5 dosimeter—any device used to determine the equilibrium absorbed dose in the material and at the irradiation position of
interest.Examplesofsuchdevicesincludethermoluminescencedosimeters(TLDs),liquidchemicaldosimeters,andradiochromic
dye films. (See Practice E668, for a discussion of TLDs.)
3.6 equilibrium absorbed dose—absorbed dose at some incremental volume within the material in which the condition of
1
This method is under the jurisdiction of ASTM Committee E10 on Nuclear Technology and Applications and is the direct responsibility of Subcommittee E10.07 on
Radiation Dosimetry for Radiation Effects on Materials and Devices.
Current edition approved Jan.Dec. 1, 2005.2010. Published January 2005.2011. Originally approved in 1988. Last previous approved in 20002005 as E1250-88(20005).
DOI: 10.1520/E1250-88R05.10.1520/E1250-10.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
E1250 – 10
electronchargedparticleequilibrium(theenergies,number,anddirectionofchargedparticlesinducedbytheradiationareconstant
throughout the volume) exists. (See Terminology E170.)
4. Significance and Use
4.1 Although Co-60 nuclei only emit monoenergetic gamma rays at 1.17 and 1.33 MeV, the finite thickness of sources, and
encapsulation materials and other surrounding structures that are
...
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