Reflectron lenses are widely used in time-of-flight (TOF) mass spectrometers to generate an electrostatic field for controlling ion flow, delivering high resolution and long flight path.
Complex multi-piece stacked ring assemblies are used in the existing reflectron-type TOF-MS instruments, which demand lengthy assembling and cleaning processes. In addition, each layer of these assemblies is provided a voltage divider to control the electric field.
The standard stacked ring reflectron lenses that are currently being used in mass spectrometers can be replaced by segmented monolithic lenses produced 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 generation of a highly uniform electric field. The resistive glass products are made up of a proprietary lead silicate glass that forms an integral semiconductive layer over the glass surface.
Based on the findings of previous studies on a resistive glass reflectron tube in an orthogonal TOF system, the resistive glass tubes were found to have low FWHM values which denote improved energy focus.
In addition, the comparative spectra between the resistive glass tube and standard stacked ring assembly were found to be almost similar. Figure 1 shows the schematic of resistive glass tubes.
Figure 1. Schematic of Resistive Glass tubes
PHOTONIS’ Manufacturing Technique
In 2012, PHOTONIS was granted a patent to manufacture varied, non-linear electric fields in resistive glass tubes. The new manufacturing technique can help designers to generate non-linear and dynamic fields in the lens, ensuring improved instrument performance. Axial lines serve as collision cells or as segmented reflectron lenses with the addition of rings.
Advantages of Using Resistive Glass in Reflectron Lens
Reflectron lens made of resistive glass is an ideal replacement for a stacked ring assembly without any changes in ion flow. Capable of manipulating the electric field within the resistive glass tube, this single piece assembly is a form-fit-function replacement for the multi-piece stacked ring assemblies.
This innovation avoids the time-consuming cleaning and assembly process used for stacked ring lenses. Water and solution like IPA, methanol or acetone can be used for cleaning resistive glass without affecting its performance. The resistive glass is scratch resistant under 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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