# Mean Free Path

A working notebook on vacuum: the physics, the machines, and the people who run them, from industrial electron tubes through accelerators and light sources into fusion, quantum hardware, semiconductor fabrication, and space. Written from inside the work by Pierre F. Ribault.

Site: https://pierreribault.com
Author: Pierre F. Ribault (vacuum scientist)
Contact: pierre@pierreribault.com

## Sections

- Essays: https://pierreribault.com/essays/
- Field Notes: https://pierreribault.com/field-notes/
- The Matter: https://pierreribault.com/matter/
- Properties table: https://pierreribault.com/matter/properties/
- Actors: https://pierreribault.com/actors/
- The Intersection: https://pierreribault.com/actors/intersection/
- The Stack: https://pierreribault.com/stack/
- Academy: https://pierreribault.com/academy/
- Dates: https://pierreribault.com/dates/
- The Frontier: https://pierreribault.com/frontier/
- The Scale: https://pierreribault.com/scale/
- Tools: https://pierreribault.com/tools/
- Bill of Vacuum: https://pierreribault.com/build/
- The dossier: https://pierreribault.com/build/bov/
- About: https://pierreribault.com/about/
- RSS: https://pierreribault.com/rss.xml

## Actors sub-pages

- The world map: https://pierreribault.com/actors/world/
- The intersection (ceramic-vacuum): https://pierreribault.com/actors/intersection/
- The Bay Area: https://pierreribault.com/actors/bay-area/
- Accelerators: https://pierreribault.com/actors/accelerators/
- Brazing ecosystem: https://pierreribault.com/actors/brazing/

## The Stack

- Regimes & Pumps: https://pierreribault.com/stack/pumps/
- Gauges: https://pierreribault.com/stack/gauges/
- Seals & Materials: https://pierreribault.com/stack/seals/
- Brazing: https://pierreribault.com/stack/brazing/
- Insulators: https://pierreribault.com/stack/insulators/
- Tubes & Klystrons: https://pierreribault.com/stack/tubes/
- The Big Machines: https://pierreribault.com/stack/machines/

## Tools

- RGA Abacus: https://pierreribault.com/tools/rga-abacus/
- RGA Spectrum Reading Abacus: https://pierreribault.com/tools/spectrum-abacus/
- Vacuum Regime Abacus: https://pierreribault.com/tools/regime-abacus/
- Brazing Abacus: https://pierreribault.com/tools/brazing/
- Brazing Route Engine: https://pierreribault.com/tools/brazing/routes/
- Outgassing base: https://pierreribault.com/tools/outgassing/
- Vacuum calculators: https://pierreribault.com/tools/outgassing/#calculate

## Academy

- The Mean Free Path: https://pierreribault.com/academy/mean-free-path/
- Surface Science: https://pierreribault.com/academy/surface-science/
- Outgassing & Temperature: https://pierreribault.com/academy/outgassing-temperature/
- Why We Bake: https://pierreribault.com/academy/why-we-bake/
- Vent Physics: https://pierreribault.com/academy/vent-physics/
- Pumps & Conductance: https://pierreribault.com/academy/pumps-conductance/
- Pressure Signatures: https://pierreribault.com/academy/pressure-signatures/
- The RGA Machine: https://pierreribault.com/academy/rga-machine/
- The Quadrupole: https://pierreribault.com/academy/quadrupole-sim/
- Reading a Spectrum: https://pierreribault.com/academy/reading-spectrum/
- The HC Threshold: https://pierreribault.com/academy/hc-threshold/
- Leak Trainer: https://pierreribault.com/academy/leak-trainer/
- Bake Race: https://pierreribault.com/academy/bake-race/
- Troubleshooting: https://pierreribault.com/academy/troubleshooting/

## Essays (published)

- A number is a claim (2026-09-01): https://pierreribault.com/essays/a-number-is-a-claim/
- Clean Has No Unit (2026-08-24): https://pierreribault.com/essays/clean-has-no-unit/
- The Warhead Dividend (2026-08-09): https://pierreribault.com/essays/the-warhead-dividend/
- The Banned Shelf (2026-07-30): https://pierreribault.com/essays/the-banned-shelf/
- The Floor Under the Fab (2026-07-13): https://pierreribault.com/essays/the-vacuum-lock/
- The Names Nobody Cites (2026-07-07): https://pierreribault.com/essays/the-names-nobody-cites/
- No Dashboard Pumps Faster (2026-06-29): https://pierreribault.com/essays/no-dashboard-pumps-faster/
- Tight Enough (2026-06-17): https://pierreribault.com/essays/tight-enough/
- The Better Ceramic (2026-06-11): https://pierreribault.com/essays/the-better-ceramic/
- The Arc (2026-06-02): https://pierreribault.com/essays/the-arc/
- Everything Outgasses (2026-05-31): https://pierreribault.com/essays/everything-outgasses/

## Essays markdown mirrors

Every published essay is also served as raw markdown at the same slug with a `.md` suffix (M3). Frontmatter carries title, subtitle, date and canonical URL ; the sources block is appended after the body.

- A number is a claim (md): https://pierreribault.com/essays/a-number-is-a-claim.md
- Clean Has No Unit (md): https://pierreribault.com/essays/clean-has-no-unit.md
- The Warhead Dividend (md): https://pierreribault.com/essays/the-warhead-dividend.md
- The Banned Shelf (md): https://pierreribault.com/essays/the-banned-shelf.md
- The Floor Under the Fab (md): https://pierreribault.com/essays/the-vacuum-lock.md
- The Names Nobody Cites (md): https://pierreribault.com/essays/the-names-nobody-cites.md
- No Dashboard Pumps Faster (md): https://pierreribault.com/essays/no-dashboard-pumps-faster.md
- Tight Enough (md): https://pierreribault.com/essays/tight-enough.md
- The Better Ceramic (md): https://pierreribault.com/essays/the-better-ceramic.md
- The Arc (md): https://pierreribault.com/essays/the-arc.md
- Everything Outgasses (md): https://pierreribault.com/essays/everything-outgasses.md

## Data

Datasets are published as JSON endpoints under /data/, licensed CC BY 4.0. Every file carries { dataset, version, updated, license, attribution, canonical, data }.

- Actors (world map): https://pierreribault.com/data/actors-world.json
- Actor control (ownership + chokepoints): https://pierreribault.com/data/actor-control.json
- Frontier (physics x sectors matrix): https://pierreribault.com/data/frontier.json
- RGA reference library (mass table, cracking patterns, ratios): https://pierreribault.com/data/rga-library.json
- Matter (materials, workhorses, banned, future): https://pierreribault.com/data/matter-materials.json
- Ceramic vacuum intersection (suppliers x system classes): https://pierreribault.com/data/ceramic-vacuum.json
- Brazing (rules, expansion curves, pairs, joint geometries, derived expansion budget): https://pierreribault.com/data/brazing.json
- Outgassing (sourced specific rates, bakeout procedures, published thresholds, pumping-time curves): https://pierreribault.com/data/outgassing.json

## Full text

- All essays, full text, one document: https://pierreribault.com/llms-full.txt