Cf-252 FTC-CFZ-431
Overview
An official document for the CF-252 source with serial number FTC-CFZ-431 provides a value for the neutron rate and CF-252 mass as of 03/19/1993.
The initial neutron rate and mass of cf-252 are stated to be [math]\displaystyle{ 10^{7}s^{-1} }[/math] and 4.2[math]\displaystyle{ \mu g }[/math], respectively.
4.2 [math]\displaystyle{ \mu g }[/math] would generate [math]\displaystyle{ 9.67 \times 10^{6} }[/math] neutrons per second. The discrepancy between these two numbers gives a 2% error.
Calculation
Click here to open a table giving neutron rates and C-252 activity from dates 1/2017 to 12/2029. This calculation only includes neutrons from Cf-252, since all other daughter nuclei and possible impurities have a very low SF rate compared to Cf-252.
Formula used for neutron rate: [math]\displaystyle{ k=(0.5)^(\frac{(year-1993)+\frac{month-3}{12}}{2.645} }[/math]
[math]\displaystyle{ n_{0}rate=9.835\times10^6\times k }[/math]
and for Cf-252 activity:
[math]\displaystyle{ activitry=2283.3\times k }[/math]