A scanning electron microscope, built one gate at a time.
Explore the beam and scan settings in Beam Lab, follow the decisions in the build journal, or inspect the system map below. This home-built SEM project is inspired by Ben Krasnow / Applied Science.
The SEM budget and milestone review runs monthly from 26 September 2026. The workbook tracks the budget and purchasing plan; this page records the evolving design.
Measure current at the specimen.
The selected low-cost route uses an insulated conductive holder, a sealed feedthrough and an external LMC662 current amplifier + ADS1115 ADC. The detector needs low-voltage rails, without an additional scintillator or PMT high-voltage supply.
Try the scan before building it.
Beam Lab includes seven synthetic specimens, field and electron visualizations, electrical connections, cited formulas and editable ESP32 scan code. The DAC80502 provides 16-bit X/Y commands to external scan amplifiers.
The detailed butterfly preset uses 512 × 512 pixels over 140 µm: about 1 h 49 min of modeled acquisition, shown in roughly 13 s at 500× playback. The synthetic image does not establish real microscope resolution. Inspect the detector wiring →
System map / vacuum to pixels
planning diagram · hover, click, or tab through parts
Optics are provisional: this map retains the preliminary two-stage electrostatic lens layout. Beam Lab explores an effective magnetic-lens model; the physical lens design is still to be selected.
The current path measures net charge absorbed by the specimen. The earlier Everhart–Thornley option uses a scintillator and PMT to detect emitted secondary electrons; it remains an alternative, with different contrast and power requirements. The microscope's accelerating supply still operates at kilovolt levels. Current-detector wiring and commissioning →
12-month project plan
₹10k monthly envelope · carry forward unused balance
| window | gate | release condition |
|---|---|---|
| 26 Sep 2026 | review 01 | freeze scope, safety checklist, chamber survey |
| months 1–3 | vacuum | leak-tested chamber and stable roughing |
| months 4–6 | electron gun | repeatable emission with interlocks |
| months 7–9 | optics + scan | focused beam and calibrated X/Y sweep |
| months 10–12 | detector | first stable image, logged settings |