Chapter 10
Identification of Radioactive Isotopes
10.1 Introduction
In radiochemical work, our interests are to identify the isotope, as well as measure
the activity accurately present in the sample. Identification of isotope is necessary
for analytical work like activation analysis, nuclear reaction studies (where nature
of isotope formed is unknown), type of radioactive isotope present in contaminated
food etc.
In most of these cases, one can identify the isotope by determining the halflife of the isotope, as well as by the nature of radiations emitted by the isotope
(by obtaining its spectrum or determining its E max ). Half-life measurement and the
nature of radiation emitted by the isotope also helps to establish the purity of the
isotope present in the sample (i.e., whether the sample contains several radioactive
isotopes or a single type isotope). This information assists in selecting a suitable
radiochemical analytical technique to separate isotopes present in the sample, before
its activity is evaluated. The next step is to examine the decay scheme of the identified
isotope. Decay scheme helps in deciding the type of counter, nature of sample (liquid
or solid), type of radiation to be counted to measure the activity present in the sample.
10.2 Counter Selection
From the above mentioned preliminary investigations, we are able to decide whether
a particular isotope can be counted by a G.M. counter (i.e., for strong β-particles
or γ -rays), or proportional counter or scintillation counter. Nevertheless, since our
objective is to identify the isotope, we can resort to either proportional counter or
scintillation counter. Using either of these two counters, the energy of radiation, as
well as exact nature of radiation, can be confirmed. This is achieved by studying the
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
M. Sharon and M. Sharon, Nuclear Chemistry,
https://doi.org/10.1007/978-3-030-62018-9_10
159
Identification of Radioactive Isotopes
10.1 Introduction
In radiochemical work, our interests are to identify the isotope, as well as measure
the activity accurately present in the sample. Identification of isotope is necessary
for analytical work like activation analysis, nuclear reaction studies (where nature
of isotope formed is unknown), type of radioactive isotope present in contaminated
food etc.
In most of these cases, one can identify the isotope by determining the halflife of the isotope, as well as by the nature of radiations emitted by the isotope
(by obtaining its spectrum or determining its E max ). Half-life measurement and the
nature of radiation emitted by the isotope also helps to establish the purity of the
isotope present in the sample (i.e., whether the sample contains several radioactive
isotopes or a single type isotope). This information assists in selecting a suitable
radiochemical analytical technique to separate isotopes present in the sample, before
its activity is evaluated. The next step is to examine the decay scheme of the identified
isotope. Decay scheme helps in deciding the type of counter, nature of sample (liquid
or solid), type of radiation to be counted to measure the activity present in the sample.
10.2 Counter Selection
From the above mentioned preliminary investigations, we are able to decide whether
a particular isotope can be counted by a G.M. counter (i.e., for strong β-particles
or γ -rays), or proportional counter or scintillation counter. Nevertheless, since our
objective is to identify the isotope, we can resort to either proportional counter or
scintillation counter. Using either of these two counters, the energy of radiation, as
well as exact nature of radiation, can be confirmed. This is achieved by studying the
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
M. Sharon and M. Sharon, Nuclear Chemistry,
https://doi.org/10.1007/978-3-030-62018-9_10
159