6533b86dfe1ef96bd12ca188

RESEARCH PRODUCT

Angular spreading measurements using MeV ion microscopes

Minqin RenFrank WattThomas OsipowiczXiao ChenHarry J. WhitlowHarry J. WhitlowJeroen A. Van Kan

subject

Point spread functionNuclear and High Energy PhysicsMicroscopeIon beamta114Physics::Instrumentation and DetectorsChemistryScatteringbusiness.industryIonlaw.inventionOpticslawPhysics::Accelerator PhysicsbusinessInstrumentationBeam (structure)FOIL methodField ion microscope

description

Abstract The sharpness of MeV ion microscope images is governed by small-angle scattering and associated lateral spreading of the ion beam in the sample. We have investigated measurement of the half-angle of the angular spreading distribution by characterising the image blurring in direct-Scanning Transmission Ion Microscopy (direct-STIM). In these tests Mylar™ foils of 0.5–6 μm were used to induce angular spreading. Images were taken of an electron microscope grid using 2 MeV protons with, and without, the foils in the beam path. The blurring was measured by fitting the width of a circular Gaussian point spread function to the images with and without the foil in position. The results show the half-angle width of the spreading has a square root dependence on foil thickness that lies intermediate between SRIM predictions and the theoretical estimates (Bird and Williams fits to the Sigmund and Winterbon data and Amsel et al.).

10.1016/j.nimb.2012.11.035https://doi.org/10.1016/j.nimb.2012.11.035