Sample and detector are placed in the atmosphere which contains 1% of Ar, and Ar fluorescence X-ray is detected during the measurement. The energy of Ar-Ka is about 3.0 keV and it overlaps to the fluorescence X-rays of Cl. Ar in the air is removed when the air between sample and detector is removed by the gas (N2 or He) flush. Ar peak around 3keV disappeared and then Cl-Ka is shown clearly. The atmosphere contains 1 ppm of Kr which can be removed as well. It is possible to remove Kr-Ka peak. By removing Kr-Ka peak by N2 gas flush, Pb-Lb1 (12.6 keV) can be measured on the lowered background.
TXRF products from Rigaku
The new, next generation benchtop total reflection X-ray fluorescence (TXRF) spectrometer
Trace elemental surface contamination metrology by TXRF; up to 200 mm wafers.
Trace elemental surface contamination metrology by TXRF; up to 300 mm wafers
Ultra-trace elemental surface contamination metrology by TXRF with VPD capability; up to 300 mm wafers