Abstract
To establish a routine method of activation analysis for bromine in the plant materials, non-destructive method was studied and samples of plant materials of widely different bromine content have been analyzed by non-destructive neutron activation analysis.
According to the differences of neutron cross section, the decay constant and the content of the elements in question, the time required for neutron irradiation and cooling time were selected.
In this method, 50-300 mg of plant materials were enclosed in small polyethylene bag for irradiation.
The samples and Br-standard were then irradiated in a capsule in the JRR-1 reactor at a flux of 3 ×1011n/cm2/sec for a period of 5 hours (or JRR-2 reactor at a flux of 8×1013 n/cm2/sec for a period of 5 minutes) .
After the cooling time of 50 hours, the activity of the bromine-82 were measured, using photopeak of gamma rays of 0.77 MeV by a multi-channel pulse-hight analyser.
Precision ranges from ±3% (standard deviation) for samples with high bromine contents to ±20% for samples with low contents. This method can be applicable to the sample containing bromine as low as 0.15 ppm.
