The sensitivity of the XRF apparatus was greatly improved by means of shortening the distances from the radioisotope source to the sample and from the sample to the Si (Li) detector. A high-purity aluminum tube was inserted in the stainless steel collimator

the obstruction peak of iron in background spectrum was reduced by a factor of 12.

The concentrations of ten trace elements in 180 human hair samples from Pingdingshan. Henan province were measured by XRF. The concentrations of about ten trace elements in human hair from Pingdingshan were compared respectively with those from Tianjin and Shanghai by means of T-test

and the obvious differences in the concentrations of most corresponding elements were observed. The Fe

Cu

Ni and Se contents of human hair from Pingdingshan are on the low side of the reference values.