Note: Performance of a novel electrostatic quadrupole doublet for nuclear microprobe application

The newly designed and constructed electrostatic quadrupole doublet (EQD) at the University of North Texas (UNT) has achieved mass independent focusing of MeV particles to a spot size of 3.3 × 3.5 μm. The EQD is compared to the Louisiana magnetic doublet which is also in use at UNT. Characteristics such as demagnification and sensitivity to aberrations are simulated by the matrix raytracing software, propagation of rays and aberrations by matrices and compared for each focusing system. Particle induced x-ray emission (PIXE) maps of a 2000 mesh Cu grid are compared and show that both doublets produce suitable spot sizes for microprobe analysis. A coarser, 200 mesh grid and incident beams of 2 MeV H+ and O+ show the EQD to be stigmatic given common aperture sizes and lens potentials.