ASTM E393 - 19 - Standard Test Method for Measuring Reaction Rates by Analysis of Barium-140 From Fission Dosimeters

ASTM E393 - 19

Standard Test Method for Measuring Reaction Rates by Analysis of Barium-140 From Fission Dosimeters

Status : Current   Published : November 2019



1.1 This test method describes two procedures for the measurement of reaction rates by determining the amount of the fission product 140Ba produced by the non-threshold reactions 235U(n,f), 241Am(n,f), and 239Pu(n,f), and by the threshold reactions 238U(n,f), 237Np(n,f), and 232Th(n,f).

1.2 These reactions produce many fission products, among which is 140Ba, having a half-life of 12.752 days. 140Ba emits gamma rays of several energies; however, these are not easily detected in the presence of other fission products. Competing activity from other fission products requires that a chemical separation be employed or that the 140Ba activity be determined indirectly by counting its daughter product 140La. This test method describes both procedure ( a), the nondestructive determination of 140Ba by the direct counting of 140La several days after irradiation, and procedure ( b), the chemical separation of 140Ba and the subsequent counting of 140Ba or its daughter 140 La.

1.3 With suitable techniques, fission neutron fluence rates can be measured in the range from 10 7 n (neutrons) · cm −2 · s −1 to approximately 10 15 n · cm −2 · s −1.

1.4 The measurement of time-integrated reaction rates with fission dosimeters by 140Ba analysis is limited by the half-life of 140Ba to irradiation times up to about six weeks.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6  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.

1.7  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.

Standard NumberASTM E393 - 19
TitleStandard Test Method for Measuring Reaction Rates by Analysis of Barium-140 From Fission Dosimeters
Publication Date01 November 2019
Normative References(Required to achieve compliance to this standard)No other standards are normatively referenced
Informative References(Provided for Information)No other standards are informatively referenced
Descriptors Barium-140, fission dosimeter, fission product, fission reaction rates
File Size104 KB

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