Berthold LB 444 - One-Point Calibration

Density Meter LB 444 SECTION 6. BASICS OF DENSITY MEASUREMENTS
61
One-Point Calibration
For one-point calibration one needs a value pair (countrate and density or con-
centration 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 following 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
ρ
ρ
ρ
x
=
C
-
C - C
max min
⋅⋅
∆ρ
∆
max min
Example 1:
Isotope: Cs-137
Crystal: 40/35; frontal irradiation
ρ
max
= 1.098: C
ρ
max
= 20 %
ρ
min
= 1.045: C
ρ
min
= 10 %
C
ρ
= Concentration in % at respective density value
µ
%
= -0.0664
1.098 - 1.045
20 10
= -0.000352
−
C
ρ
= Concentration in % at respective density value
Example 2: