Astm D 3649 – 98a pdf free download

Standard Practice for
High-Resolution Gamma-Ray Spectrometry of Water1

This standard is issued under the fixed designation D 3649; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of the last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope

1.1 This practice covers the measurement of gamma-ray
emitting radionuclides in water by means of gamma-ray
spectrometry. It is applicable to nuclides emitting gamma-rays
with energies greater than 20 keV. For typical counting systems
and sample types, activity levels of about 40 Bq are easily
measured and sensitivities as low as 0.4 Bq are found for many
nuclides (1).2 Count rates in excess of 2000 counts per second
should be avoided because of electronic limitations. High
count rate samples can be accommodated by dilution or by
increasing the sample to detector distance.

1.2 This practice can be used for either quantitative or
relative determinations. In tracer work, the results may be
expressed by comparison with an initial concentration of a
given nuclide which is taken as 100 %. For radioassay, the
results may be expressed in terms of known nuclidic standards
for the radionuclides known to be present. In addition to the
quantitative measurement of gamma radioactivity, gamma
spectrometry can be used for the identification of specific
gamma emitters in a mixture of radionuclides. General information on radioactivity and the measurement of radiation has
been published (2,3). Information on the specific applications of
gamma spectrometry is also available in the literature (4). See
also Practice D 1066, Test Method D 1943, Practice D 3084,
Practice D 3085, Practices D 3370, and Method E 181.

1.3 This standard does not purport to address 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
limitation prior to use.

2. Referenced Documents

2.1 ASTM Standards:
D 1066 Practice for Sampling Steam3
D 1129 Terminology Relating to Water3
D 2777 Practice for Determination of Precision and Bias of