• There are no items in your cart

ASTM E 262 : 2013

Superseded

Superseded

A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.

View Superseded by

Standard Test Method for Determining Thermal Neutron Reaction Rates and Thermal Neutron Fluence Rates by Radioactivation Techniques

Available format(s)

Hardcopy , PDF

Superseded date

05-20-2024

Superseded by

ASTM E 262 : 2017

Language(s)

English

Published date

01-01-2013

US$83.00
Excluding Tax where applicable

Committee
E 10
DocumentType
Test Method
Pages
11
PublisherName
American Society for Testing and Materials
Status
Superseded
SupersededBy
Supersedes

1.1The purpose of this test method is to define a general procedure for determining an unknown thermal-neutron fluence rate by neutron activation techniques. It is not practicable to describe completely a technique applicable to the large number of experimental situations that require the measurement of a thermal-neutron fluence rate. Therefore, this method is presented so that the user may adapt to his particular situation the fundamental procedures of the following techniques.

1.1.1Radiometric counting technique using pure cobalt, pure gold, pure indium, cobalt-aluminum, alloy, gold-aluminum alloy, or indium-aluminum alloy.

1.1.2Standard comparison technique using pure gold, or gold-aluminum alloy, and

1.1.3Secondary standard comparison techniques using pure indium, indium-aluminum alloy, pure dysprosium, or dysprosium-aluminum alloy.

1.2The techniques presented are limited to measurements at room temperatures. However, special problems when making thermal-neutron fluence rate measurements in high-temperature environments are discussed in 9.2. For those circumstances where the use of cadmium as a thermal shield is undesirable because of potential spectrum perturbations or of temperatures above the melting point of cadmium, the method described in Test Method E481 can be used in some cases. Alternatively, gadolinium filters may be used instead of cadmium. For high temperature applications in which aluminum alloys are unsuitable, other alloys such as cobalt-nickel or cobalt-vanadium have been used.

1.3This test method may be used to determine the equivalent 2200 m/s fluence rate. The accurate determination of the actual thermal neutron fluence rate requires knowledge of the neutron temperature, and determination of the neutron temperature is not within the scope of the standard.

1.4The techniques presented are suitable only for neutron fields having a significant thermal neutron component, in which moderating materials are present, and for which the average scattering cross section is large compared to the average absorption cross section in the thermal neutron energy range.

1.5Table 1 indicates the useful neutron-fluence ranges for each detector material.

TABLE 1 Useful Neutron Fluence Ranges of Foil Material

Foil Material

Form

Useful Range (neutrons/cm 2)

Indium

pure or alloyed with aluminum

103 to 1012

Gold

pure or alloyed with aluminum

107 to 1014

Dysprosium

pure or alloyed with aluminum

103 to 1010

Cobalt

pure or alloyed with aluminum

1014 to 1020


1.6This 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.

Access your standards online with a subscription

Features

  • Simple online access to standards, technical information and regulations.

  • Critical updates of standards and customisable alerts and notifications.

  • Multi-user online standards collection: secure, flexible and cost effective.