What pumping speed actually reaches the chamber?

The chamber is the node. A branch starts at its pump: put a pump on a port, then lay its line back toward the chamber, section by section, until it reaches. Click the dashed section to lay a piece, press Enter, lay the next. Drag the drawing to turn it. Proportions are representative, only the typed dimensions are computed, and the molecular regime is the only one these formulas hold in.

P. Chiggiato, Vacuum Technology for Ion Sources, CERN, Geneva, arXiv:1404.0960. Read here: Eq. 20 C = C′ A₁ τ. Eq. 21 the Santeler equation for the transmission probability of a uniform circular tube, stated to better than 0.7 per cent. Eq. 22 its long tube limit. Eq. 23 C ≈ 12.3 D³/L for N₂. Table 8 unit area conductances at 293 K. F-CHIGGIATO-IONSOURCES

E. Al-Dmour, Fundamentals of Vacuum Physics and Technology, Proceedings of the 2017 CERN Accelerator School course on Vacuum for Particle Accelerators, Glumslov, arXiv:2006.01464. Read here: Eq. 47 C = 3.64 A √(T/M) for a thick orifice. Eq. 48 C = 11.6 A for air at 23 C. Eq. 49 C = 3.81 (d³/L) √(T/M) for a long circular tube. Eq. 50 C = 12.1 d³/L for air at 23 C. Eq. 51 1/S_eff = 1/C + 1/S_nom. F-ALDMOUR-CAS2017

V. Baglin, Cryopumping and Vacuum Systems, Proceedings of the 2017 CERN Accelerator School course on Vacuum for Particle Accelerators, Glumslov, Sweden, arXiv:2006.01574. Read here: Eq. 4 S = (1/4) σ (1 - P/P_vap) A V̄ ≈ (1/4) σ A V̄, a cold surface as a pump. Eq. 5 S = 3.64 σ √(T/M) in L s⁻¹ cm⁻², with the published control that at 4.2 K the maximum pumping speed of hydrogen and carbon monoxide equals 5.3 and 1.4 L s⁻¹ cm⁻². Eq. 7 P₁/P₂ = √(T₁/T₂) and n₁/n₂ = √(T₂/T₁), thermal transpiration, with the published controls that a vessel at 4.2 K reads the measured pressure divided by 8 and one at 77 K divided by 2. Table 2, peak desorption temperatures H2 18 K, CH4 60 K, H2O 285 K, CO 45 K, CO2 95 K. Section 2.1, cooling a metallic surface to 77 K will only pump water molecules. Section 3.4, one shall operate below 4 K to reach a low vapour pressure of helium. F-BAGLIN-CAS2017

V. Parma, Cryostat Design, Proceedings of the CAS-CERN Accelerator School course on Superconductivity for Accelerators, Erice, Italy, 2013, CERN-2014-005 pp. 353-399, arXiv:1501.07154. Read here: Eq. 18, Kennard law, Q̇ = A₁ · α(T) · Ω · p · (T₂ - T₁) in the molecular regime, with p in Pa, temperatures in K, and Ω = 2.13 W m⁻² Pa⁻¹ K⁻¹ published for helium. Eq. 19 for the combined accommodation coefficient of two surfaces. Table 4, accommodation coefficients, helium 0.3 at 300 K, 0.4 at 80 K, 0.6 at 20 K, 1 at 4 K, air 0.8 at 300 K and 1 at 80 K. Section 3.2, at 4.2 K most gas species except H2 and He can be cryo-condensed on the cold surfaces. F-PARMA-CAS2013

Edwards, nXDS Scroll Pump Instruction Manual, A735-01-880 Issue B, Original Instructions, mirrored at mmrc.caltech.edu. Read here: Table 6, General mechanical data, section 2.3.1, overall dimensions L x W x H 432 x 282 x 302 mm, nominal rotational speed 1800 rpm at 30 Hz, inlet connection NW25 and outlet connection NW25. Figure 1 and its item list, lifting eye, NW25 inlet port, gas ballast control, cooling fan, NW25 exhaust port, rubber feet, user interface panel. S-EDWARDS-NXDS

Caburn-MDC Europe Limited, catalogue section 2, Valves, gate valves Million cycle line MC+, angle valves Million cycle line MC, all-metal valves and butterfly valves, www.caburn.co.uk. Read here: Section 2.1, gate valves, one page per port size, CF port connections, giving the face to face of the body, 38 mm at DN16, 50.8 at DN40, 70 at DN63, 80 at DN160, 85 at DN200 and 102 at DN250, with the bore, the flange outer diameter, the bolt circle and the number of bolts on each. Section 2.3, angle valves, axis to face equal on both ports, 38 mm at DN16, 63 at DN40, 105 at DN63, 135 at DN100, 165 at DN160 and 216 at DN200. Section 2.5, all-metal angle valve DN16, legs of 38 mm on a 34 mm flange with a 14.5 mm bore, stainless steel bellows sealed actuator and a formed bellows. Section 2.5, butterfly valves, table giving flange outer diameter, knob height, through bore and thickness, 19.1 mm thick at DN16CF and 25.4 at DN40CF. S-CABURN-MDC-VALVES

K. Jousten, Vacuum gauges for the fine and high vacuum, CERN Accelerator School, Vacuum in Accelerators, Platja d’Aro, 16-24 May 2006. Read here: Diapositive 9, vue d ensemble des principes : le groupe capacitance/piezo/piezoresistif/membrane est etiquete "Gas independent, total pressure, p = F/A", le groupe conduction thermique (Pirani, thermocouple) est etiquete "Gas dependent, difficult to interpret". Diapositive 30, facteur de correction Helium/Azote mesure sur quatre jauges Pirani commerciales (Pfeiffer, Thyracont, MKS, Leybold), de 0,95-1,20 en dessous de 0,1 mbar a quasi 0 au-dela de 10 mbar. Diapositive 44, tableau "Relative measurement uncertainty of commercially available vacuum gauges" : Pirani gauges, measurement range 1e-1 to 1e4 Pa. Capacitance diaphragm gauges, measurement range 1e-4 to 1e5 Pa. S-JOUSTEN-CAS2006-FINE

K. Jousten, Ultrahigh vacuum gauges, CERN Accelerator School, Vacuum in Accelerators, Platja d’Aro, 16-24 May 2006. Read here: Diapositives 8 a 17, la jauge Penning : schema a champs electrique et magnetique croises (vecteur B nomme sur le schema), le champ magnetique est constitutif du principe, pas un reglage annexe. Diapositives 19 a 22, effets dans la jauge Bayard-Alpert : 1 l ionisation voulue, 2 la desorption stimulee par electrons (ESD), 3 l effet de rayons X, 4 l effet de rayons X inverse : les effets 2 et 3 plafonnent la lecture a basse pression, la jauge a extraction reduit ce courant residuel par une geometrie qui eloigne le collecteur du volume d ionisation plutot que par un champ supplementaire. Diapositive 44, meme tableau que S-JOUSTEN-CAS2006-FINE : Penning gauges, measurement range 1e-7 to 1 Pa. Ionisation gauges (emission cathodes, Bayard-Alpert et extracteur), measurement range 1e-10 to 1e-2 Pa. S-JOUSTEN-CAS2006-UHV

INFICON, IE414 and IE514 Sensors, High-end Hot Ion Gauges, Passive, datasheet tiba70e1-b, 2024. Read here: Table des specifications, ligne "Measurement range (N2)" : IE414, jauge a systeme Bayard-Alpert, 2e-11 a 1e-2 mbar. IE514, jauge a systeme extracteur, 2e-12 a 1e-4 mbar. Page de garde, limite de rayons X annoncee : IE414 moins de 1e-11 mbar, IE514 moins de 1e-12 mbar. S-INFICON-IE414-IE514

MKS Instruments, 631F, Heated Absolute Baratron Capacitance Manometer, datasheet 631F_11/21, 2021. Read here: Table des specifications, ligne "Full Scale Pressure Ranges" : 1, 2, 10, 30, 100 et 1000 Torr (mmHg). Table des codes de commande, page 4, la gamme 1000 Torr porte le code "13", une configuration reellement vendue. S-MKS-631F

Outgassing rates are read from the outgassing base by material and surface state, and the key of each reading travels with the result into the dossier.

Flange, tube and bellows dimensions come from VACOM Vakuum Komponenten und Messtechnik GmbH, Vacuum Components, chapter 1, KF Components, ISO Components, CF Components, www.vacom-vacuum.com, read in its dimension tables. Nothing in the drawing is set at the eye, and a bore no table carries says on its face that it is typed. S-VACOM-COMPONENTS

• Dimensions of CF Flanges, to ISO 3669 and its pre-norm ISO/TS 3669-2, DN10 to DN250, 12 bores. Read here: outer diameter, thickness, copper gasket diameter, bolt circle, number and size of bolts.
• Dimensions of KF flanges / KF centering rings, to DIN 28403 and ISO 2861, DN10 to DN50, 5 bores. Read here: outer diameter, centring ring diameter, clamp diameter, flange height.
• Dimensions of ISO-K flanges and centering rings, to DIN 28404 and ISO 1609, DN63 to DN400, 8 bores. Read here: outer diameter, centring ring diameter, thickness, number of clamps and of claw clamps with their size.
• CF Tube, 1 m length, KF Tube, 1 m length, ISO Tube, 1 m length, to DIN 11850, DN16 to DN200, 9 bores. Read here: outer diameter and wall thickness, the wall you see at the cut end of a drawn tube, DN25 read at the KF table because the CF one leaves it out as an auxiliary bore.
• Dimensions of ISO-K flanges and centering rings, rows D2 and RA, the tube inner and outer diameter, DN250. Read here: the only place in the catalogue that carries a tube at this bore, 250 inside and 254 outside.
• CF Hydroformed bellows, 1 flange rotatable, KF Hydroformed bellows connectors, ISO-K Hydroformed bellows connectors, under no norm the catalogue names, DN16 to DN250, 10 bores. Read here: free length and compressed length by bore, and nothing about the shape of the convolutions.

The straight tube goes through the Santeler equation for the transmission probability, which is the closed form that approaches Clausing's result, and through the rule that a duct conducts its entrance aperture times that probability. That is what makes a short tube calculable: the familiar long-tube formula overestimates a tube one diameter long by more than a factor of two.

Outside the molecular regime the calculator refuses and names the regime instead of returning a number. Every formula here is a molecular-flow formula, and applying one where it does not hold would produce a figure that looks measured and is not.

The unit governs every pressure this page computes, and it lives in the masthead next to Search. Values quoted from a document keep the unit their source printed.

The elbow, the bellows and the gate valve are shop rules. No document opened for this page publishes a formula for them: they are drawn dashed, counted as unsourced in the table, and no correction factor was invented to close the gap.

A tee carries 3 openings and a cross 4, all of them equal. The one the line arrives by is taken, and every other one is a port of its own: it takes the line onward, a blank flange with its gasket, a gauge, or a pump. A tee or a cross conducts like a tube 2 diameters long with its side ports ignored, which is a shop rule and no published result, so it is drawn dashed like the elbow and the valve.

The face a gasket shows the gas is a ring, pi times the bore times 0.3 cm of exposed height. That height is a convention of this page: no opened document publishes it, and it depends on the torque, the crush and the flange standard. The outgassing rate of the gasket material is not a convention, it is read from the base with its key.

While a piece is being laid, the bore one step up is drawn as a dashed ghost at the same place. It advises nothing: it shows the room that bore would ask for before you read what it would gain.

What would close the gap on the elbow is D.H. Davis, Monte Carlo calculation of molecular flow rates through a cylindrical elbow and pipes of other shapes, J. Appl. Phys. 31 (1960) 1169, cited by both documents this page reads and not yet opened. Until it is, no correction factor is invented.