July 6, 2007 Neutron Capture in lead

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Paraffin wax layer of thickness 12.6 cm was used as a neutron attenuator and for cosmic rays lead of thickness 10 cm on sides of HpGe detector. The source was Cf-252 without and with lead container of 60μCi activity.

1. Energy Region 100-500 keV

With lead without CF 252 gamma spectra100 500.jpg

2. Energy Region 500-900 keV

With lead without CF 252 gamma spectra500 900.jpg
We have sharp peak on 803 keV, which is the result of the lead container. This line coressponds to thermal-neutron capture in lead Pb-206.[1]. However, 388 kev and 333 kev, energy lines of Cf-249 are more dominant without lead.
For energy line 803 keV ( # of counts without lead / # of count with lead ) =0.5

(n,[math]\gamma) from Pb-206 from 1 ev to 600 keV[/math]