Abstract

The electrostatic ion beam trap (EIBT) was designed by D. Zajfman during the previous decade. This ion trap combines many properties of the Fourier-transform ion cyclotron resonance (FTICR) mass analyzer and time-of-flight (TOF) mass analyzer. There are several advantages for the electrostatic ion beam trap. First, large mass-to-charge particles in an electrostatic field could be easier to analyze. Second, there is a folded flight path, which could make the mass analyzer smaller compared to conventional TOF mass analyzer. This principle of operation of this ion trap is analogous to an optical resonator. The ions are trapped in a voltage valley and oscillate between the two parallel sets of mirror electrodes with high voltages. In this thesis, I first describe a new type of miniaturized electrostatic ion beam trap mass analyzer that consists of two printed circuit boards (PCBs). The facing surfaces of these boards are imprinted with copper electrodes. The center of the boards is field free and at ground potential with ion mirrors and Einzel lenses on either side. A charge detector is attached to the center for recording the time-dependant motion of the ions in the field. The PCB-based EIBT design is easier to construct than the original EIBT mass analyzer. The electrostatic fields are optimized by adjusting the potential on the mirror electrodes as well as the geometry of the electrodes. Although nondestructive charge detection is much less sensitive for small ions, this detection is ideal for analysis of large ions. The planar electrostatic ion beam trap is inexpensive, small, and simple to operate. The PCB EIBT device was designed, built, and tested using metal samples such as copper and nickel. The electric field of the PCB EIBT is not the same as that of the original EIBT. Unfortunately, there were no ion signals captured in image charge detector. Another new type of miniaturized electrostatic ion beam trap was made by depositing electrodes onto Kapton film. Seven thin tin/copper traces (1 mm wide by 0.015 mm thick) were deposited onto each side of a flat, flexible circuit board substrate (Kapton film 0.15 mm thickness). The film was rolled to form a cylinder. The flexible EIBT is small (4.5 cm × 8 cm), and lightweight (~1 g). This device was tested using laser ablation of CsI. The CsI signals were detected by the charge detector, amplified and sent to the oscilloscope. Fourier transformation was used to convert the data to the frequency domain spectrum. The resolution of Cs+ is around 1000 (m/Δm) from initial flexible EIBT test. The mass accuracy of the Cs+ peak is better than 0.1%.

Degree

College and Department

Physical and Mathematical Sciences; Chemistry and Biochemistry

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