Benchtop TXRF Gas Flush Mechanism

Introduction

An incident X-ray beam impinges upon the sample at a shallow angle resulting in virtually complete reflection of the excitation beam away from the silicon drift detector (Figure 1). This affords dramatically reduced background contributions in the measured energy dispersive X-ray fluorescence spectra.  The fast and easy operation is provided under air atmosphere and with gas flush mechanism.

Figure 1: TXRF principle

Measurement and results

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-Kα is about 3.0 keV and it overlaps to the fluorescence X-rays of Cl as shown in Figure 3.

Ar in the air is removed when the air between sample and detector is removed by the gas (N₂ or He) flush (Figure 2). The Ar peak around 3 keV disappeared and then Cl-Kα is shown clearly (Figure 3). 

Figure 2: Gas flushing 

Figure 3: The effect of the removal of Ar-Kα by N₂ gas flush

The atmosphere contains 1 ppm of Kr which can be removed as well. It is possible to remove the Kr-Kα peak. By removing the Kr-Kα peak by N₂ gas flush, Pb-Lβ₁ (12.6 keV) can be measured on the lowered background. (Figure 4).

Figure 4: Removal of Kr-Kα