132
7 Non-conventional Detection Techniques
1
2
3
4
Scanning by GM length wise
THE FRONT ZONE NUMBER:
1. ORIGINAL SPOT
3. SODIUM IONS ( NA )
24
+
2. POTASSIUM IONS ( K )
42 +
4. BROMIDE IONS ( Br )
80 –
)
pm
(c y
ivit
Act
Fig. 7.5 A plot of count rate versus paper length of a paper chromatogram used for separating a
mixture of radioactivity present as 24 Na, 80 Br, and 42 K. The paper chromatogram was scanned while
keeping G.M. counter fixed at one position. Peak of activity 1 = original spot on the paper, 2 =
confirmed to be 4 2K + ions, 3 = confirmed to be 24 Na + ions, and 4 = confirmed to be 80 Br-ions
80
82
/ r
B
r
B
24 Na
Original spot
no spot
observed
24 K
b
a
Fig. 7.6 Autoradiograph of a paper chromatogram showing the separation of different constitutes
of a nuclear reactor irradiated mixture of NaBr and KBr. a Photograph of X -ray film which was
kept over the paper chromatogram for exposure in dark. Spots are identified by their half-life measurements b Photograph of X -ray film which was kept over the paper chromatogram for exposure;
in between the film and photograph paper, 11 layers of X -ray films were kept and then exposed in
dark. The spot of 24 Na has disappeared because its radiation could not penetrate 11 X -ray films
Table 7.2 Relative E max (in MeV) for β-particles emitted by these nuclides, the observed R f
factors obtained by chromatogram scan and X -ray films
Nuclide
E max (MeV)
R f factors
G.M. scanning
X -ray film
Potassium-42
3.60
0.16
0.16
Sodium-24
1.39
0.29
0.24
Bromine-80
1.99
0.81
0.83
7 Non-conventional Detection Techniques
1
2
3
4
Scanning by GM length wise
THE FRONT ZONE NUMBER:
1. ORIGINAL SPOT
3. SODIUM IONS ( NA )
24
+
2. POTASSIUM IONS ( K )
42 +
4. BROMIDE IONS ( Br )
80 –
)
pm
(c y
ivit
Act
Fig. 7.5 A plot of count rate versus paper length of a paper chromatogram used for separating a
mixture of radioactivity present as 24 Na, 80 Br, and 42 K. The paper chromatogram was scanned while
keeping G.M. counter fixed at one position. Peak of activity 1 = original spot on the paper, 2 =
confirmed to be 4 2K + ions, 3 = confirmed to be 24 Na + ions, and 4 = confirmed to be 80 Br-ions
80
82
/ r
B
r
B
24 Na
Original spot
no spot
observed
24 K
b
a
Fig. 7.6 Autoradiograph of a paper chromatogram showing the separation of different constitutes
of a nuclear reactor irradiated mixture of NaBr and KBr. a Photograph of X -ray film which was
kept over the paper chromatogram for exposure in dark. Spots are identified by their half-life measurements b Photograph of X -ray film which was kept over the paper chromatogram for exposure;
in between the film and photograph paper, 11 layers of X -ray films were kept and then exposed in
dark. The spot of 24 Na has disappeared because its radiation could not penetrate 11 X -ray films
Table 7.2 Relative E max (in MeV) for β-particles emitted by these nuclides, the observed R f
factors obtained by chromatogram scan and X -ray films
Nuclide
E max (MeV)
R f factors
G.M. scanning
X -ray film
Potassium-42
3.60
0.16
0.16
Sodium-24
1.39
0.29
0.24
Bromine-80
1.99
0.81
0.83