Reflectron lenses are extensively used in time-of-flight (TOF) mass spectrometers to produce an electrostatic field for regulating ion flow, offering high resolution and long flight paths.
Intricate multi-piece stacked ring assemblies are used in present-day reflectron-type TOF-MS instruments, which currently demand extended assembly and cleaning processes. Furthermore, each layer of these assemblies is equipped with a voltage divider to regulate the electric field.
The standard stacked ring reflectron lenses that are presently used in mass spectrometers can now be substituted by segmented monolithic lenses, which are made using resistive glass. This article describes the resistive glass manufactured by PHOTONIS.
Resistive Glass Tubes
Resistive glass tubes are used for directing charged particles with the production of a very uniform electric field. The resistive glass products are composed of a proprietary lead silicate glass that forms a primary semiconductive layer over the glass surface.
Earlier studies on a resistive glass reflectron tube in an orthogonal TOF system found that the resistive glass tubes possess low FWHM values, which denote enhanced energy focus.
Furthermore, it was found that the comparative spectra between the resistive glass tube and regular stacked ring assembly were similar. Figure 1 is a schematic representation of resistive glass tubes.
Figure 1. Schematic of resistive glass tubes
PHOTONIS’ Manufacturing Technique
In 2012, PHOTONIS received a patent to manufacture varied, non-linear electric fields in resistive glass tubes. The new manufacturing method can assist designers in producing non-linear and dynamic fields in the lens, guaranteeing enhanced instrument performance. Axial lines act as collision cells or as segmented reflectron lenses with the incorporation of rings.
Advantages of Using Resistive Glass in Reflectron Lens
The reflectron lens made of resistive glass is a perfect substitute for a stacked ring assembly without any variations in ion flow. This single-piece assembly can not only manipulate the electric field within the resistive glass tube but is also a form-fit-function replacement for the multi-piece stacked ring assemblies.
This innovation sidesteps the laborious cleaning and assembly process used for stacked ring lenses. Water and solutions such as methanol, IPA, or acetone can be used for cleaning resistive glass without interfering with its performance. The resistive glass is scratch-resistant in light-to-moderate abrasion environments.
This information has been sourced, reviewed and adapted from materials provided by PHOTONIS Technologies S.A.S.
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