Follow the beam.
From a glowing filament to the first pixel. Change a parameter. See the physics.
Instrument controls
LIVEA source of electrons
A tungsten filament, a negative cathode, and a grounded anode.
Heating sets emission. Acceleration voltage sets electron energy. The heater floats at cathode potential.
Shape & steer
Aperture, magnetic lens, and two pairs of electrostatic scan plates.
Make room for the beam
Roughing pump → backing line → turbomolecular pump → column.
Turn electrons into light
Collection cage → scintillator → light guide → photomultiplier.
An Everhart–Thornley detector collects secondary electrons. A Faraday cup measures beam current separately; it is not a photomultiplier.
Physics, as you change it.
Hover, focus, or select an equation for its derivation, assumptions, and original sources.
Write the scan.
Design a trajectory, preview it, and inspect the ESP32 control program.
From vacuum to signal.
An interactive operating sequence. Each step explains what changes and what to observe.
What this project already provides
The repository contains a low-voltage controller for an external Spellman UM6N4 acceleration supply. The floating filament supply, gun, column, vacuum equipment, lenses, scan amplifiers, and detector are additional systems. The ESP32 scan example is a proposed extension, separate from the existing analog acceleration controller.
This sequence is a learning aid. Actual setpoints, pump crossover, heater ratings, isolation, grounding, HV discharge, and interlock commissioning come from the selected equipment and the project’s engineering report.
Every equation has a source.
Live substitutions, derivations, and the limits of the model. Select any equation to explore.
Relativistic beam kinematics, a steady-state filament heat balance, ideal vacuum dynamics, paraxial optics, and a synthetic detector signal. The display uses schematic geometry and slows electron motion. Numerical readouts use SI conversions. Current, counts, and SNR equations describe the available beam and a proposed exposure; manual blanking stops acquisition. Electric-field values include the current X scan command plus alignment offset. Material contrast, coil geometry, aberrations, and emission acceptance are illustrative assumptions, not measured performance.