BERTHOLD TECHNOLOGIES LB 444 - 8.1.2 One-Point Calibration

04/03 347 LB 444
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8.1.2 One-Point Calibration
For one-point calibration one needs a value pair (count rate and density or concentration
value) and the absorption coefficient. The absorption coefficient for common products is
listed in the enclosed table (see Appendix). For products not listed there, enter the fol-
lowing values for the unit g/cm
3
.
Cs-137:
Frontal (axial)
irradiation
Lateral
irradiation
Crystal size 40/35
25/25
50/50 All crystal
sizes
Absorption coefficient µ - 0.0664 - 0.06 -0.057
Co-60:
Frontal irradiation: µ = - 0.0478
Lateral irradiation: µ = - 0.0403
For other units the absorption coefficients have to be converted as follows:
µµ µ
ρρ
ρρ
x
CCC
==
−
−
**
max min
max min
∆ρ
∆
Example 1:
Isotope: Cs-137
Crystal: 40/35; frontal irradiation
ρ
max
= 1.098 g/cm
3
: C
ρmax
= 20%
ρ
min
= 1.045 g/cm
3
: C
ρmin
= 10%
µ
%
.*
..
.=−
−
−
=−0 0664
1098 1045
20 10
0 00352
C
ρ
= Concentration in % at respective density value
Example 2:
ρ
max
= 0,95 g/cm
3
: C
ρ
max
= 30 %
ρ
min
= 0,91 g/cm
3
: C
ρ
min
= 50 %
000133.0
5030
91.095.0
*0664.0
%
=
−
−
−= µ
Input: + 1.3300e - 04