| 摘要 |
<p>A charged particle analyser comprising two opposing ion mirrors (40, 50, Fig. 2) comprising inner and outer field-defining electrode systems 510, 500 elongated along an analyser axis z. At least one arcuate focusing lens 560 is provided for constraining the arcuate divergence of a beam of charged particles 580 within the analyser whilst the beam orbits around the axis z. A disc 520 is also provided having two faces 530 at least partly spanning the space between the inner 510 and outer 500 field defining electrode systems and lying in a plane perpendicular to the axis z. The disc 520 has a resistive coating upon both faces 530. The disc has an aperture 590 for allowing passage of the charged particle beam and allows for the support of an arcuate focussing lens 560. The resistive coating allows the field within the analysis space not to be altered with the presence of the disc.</p> |
