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    ASTM E1855 - 20

    Standard Test Method for Use of 2N2222A Silicon Bipolar Transistors as Neutron Spectrum Sensors and Displacement Damage Monitors

    Active Standard ASTM E1855 | Developed by Subcommittee: E10.07

    Book of Standards Volume: 12.02


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    Significance and Use

    5.1 The neutron test spectrum must be known in order to use a measured device response to predict the device performance in an operational environment (Practice E1854). Typically, neutron spectra are determined using a set of sensors with response functions sensitive over the neutron energy region to which the device under test (DUT) responds (Guide E721). For silicon bipolar devices exposed in reactor neutron spectra, this effective energy range is between 0.01 and 10 MeV. A typical set of activation reactions that lack fission reactions from nuclides such as  235U,  237Np, or  239Pu, will have very poor sensitivity to the spectrum between 0.01 and 2 MeV. For a pool-type reactor spectrum, 70 % of the DUT electronic damage response may lie in this range making its determination of critical importance.

    5.2 When dosimeters with a significant response in the 0.01 to 2 MeV energy region, such as fission foils, are unavailable, silicon transistors can provide a dosimeter with the needed response to define the spectrum in this critical energy range. When fission foils are part of the sensor set, the silicon sensor provides confirmation of the spectral shape in this energy region.

    5.3 Silicon bipolar transistors, such as type 2N2222A, are inexpensive, smaller than fission foils contained in a boron ball, and sensitive to a part of the neutron spectrum important to the damage of modern silicon electronics. They also can be used directly in arrays to spatially map 1-MeV(Si) equivalent displacement damage fluence. The proper set of steps to take in reading the transistor-gain degradation is described in this test method.

    5.4 The energy-dependence of the displacement damage function for silicon is found in Practice E722. The major portion of the response for the silicon transistors will generally be above 100 keV.

    1. Scope

    1.1 This test method covers the use of 2N2222A silicon bipolar transistors as dosimetry sensors in the determination of neutron energy spectra and as 1-MeV(Si) equivalent displacement damage fluence monitors.

    1.2 The neutron displacement in silicon can serve as a neutron spectrum sensor in the range 0.1 to 2.0 MeV and can serve as a substitute when fission foils are not available. It has been applied in the fluence range between 2 × 1012 n/cm 2 to 1 × 1014 n/cm2 and should be useful up to 1 × 1015 n/cm2. This test method details the acquisition and use of 1-MeV(Si) equivalent fluence information for the partial determination of the neutron spectra by using 2N2222A transistors.

    1.3 This sensor yields a direct measurement of the silicon 1-MeV equivalent fluence by the transfer technique.

    1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

    1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    E170 Terminology Relating to Radiation Measurements and Dosimetry

    E261 Practice for Determining Neutron Fluence, Fluence Rate, and Spectra by Radioactivation Techniques

    E265 Test Method for Measuring Reaction Rates and Fast-Neutron Fluences by Radioactivation of Sulfur-32

    E720 Guide for Selection and Use of Neutron Sensors for Determining Neutron Spectra Employed in Radiation-Hardness Testing of Electronics

    E721 Guide for Determining Neutron Energy Spectra from Neutron Sensors for Radiation-Hardness Testing of Electronics

    E722 Practice for Characterizing Neutron Fluence Spectra in Terms of an Equivalent Monoenergetic Neutron Fluence for Radiation-Hardness Testing of Electronics

    E844 Guide for Sensor Set Design and Irradiation for Reactor Surveillance

    E944 Guide for Application of Neutron Spectrum Adjustment Methods in Reactor Surveillance

    E1854 Practice for Ensuring Test Consistency in Neutron-Induced Displacement Damage of Electronic Parts

    E2005 Guide for Benchmark Testing of Reactor Dosimetry in Standard and Reference Neutron Fields

    E2450 Practice for Application of CaF2(Mn) Thermoluminescence Dosimeters in Mixed Neutron-Photon Environments


    ICS Code

    ICS Number Code 31.200 (Integrated circuits. Microelectronics)

    UNSPSC Code

    UNSPSC Code 32111613(Bipolar or radio frequency bipolar transistor)


    Referencing This Standard
    Link Here
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    DOI: 10.1520/E1855-20

    Citation Format

    ASTM E1855-20, Standard Test Method for Use of 2N2222A Silicon Bipolar Transistors as Neutron Spectrum Sensors and Displacement Damage Monitors, ASTM International, West Conshohocken, PA, 2020, www.astm.org

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