Laser radiations Laser radiations Laser radiations Laser radiations Length Length Frequency stabilized laser (He- Ne): vacuum wavelength Frequency stabilized laser (He- Ne): absolute frequency Frequency stabilized laser (Nd- YAG, frequency doubled): vacuum wavelength Frequency stabilized laser (Nd- YAG, frequency doubled): absolute frequency Laser range finder (EDM) with flat reflector Laser range finder (EDM) with retroreflector Optical beat frequency Optical beat frequency Optical beat frequency Optical beat frequency 633 633 nm Temperature (20 ± 5) ºC 0.04 fm 2 95% No 4.31/1 474 474 THz Temperature (20 ± 5) ºC 24 khz 2 95% No 4.31/1 532 532 nm Temperature (20 ± 5) ºC 0.009 fm 2 95% No 4.31/2 563 563 THz Temperature (20 ± 5) ºC 10 khz 2 95% No 4.31/2 0 50 m 460 µm 2 95% No 5.23/13 0 50 m 102 µm 2 95% No 5.23/14 Length Laser-interferometer system: error of indicated displacement with refractive index compensation L Comparison with calibrated (laser interferometer, weather station) 0 5 m Temperature 15 C to 25 C Q[0.015, 0.031L ], L in m µm 2 95% No 5/0192 Air pressure, humidity and CO 2 content ambient pressure ± 30 hpa The BIPM key comparison database, Juin 2018 1/13
Length Laser-interferometer system: error of indicated displacement with refractive index and thermal expansion compensation L Gauge blocks: central length L Gauge blocks: thermal expansivity Gauge blocks: central length L Gauge blocks: central length L Photomask: linewidth (surveyor, engineer) tape, steel: line spacing L Comparison with calibrated standard (laser interferometer, weather station, body temperature sensors) Interferometry, exact fractions Mechanical comparison Interferometry, exact fractions Mechanical comparison Optical microscope and interferometer 0 5 m Temperature 15 C to 25 C Air pressure, humidity and CO 2 content ambient pressure ± 30 hpa Q[0.015, 0.074L ], L in m, for a = 11.5E-06 1/K µm 2 95% No 5/0193 a arbitrary 0.5 200 Q[20, 0.18L ], L in nm 2 95% No 5.4/1 Q[8.8E-06/L, 6.6E-08], L in 9.00E-06 1.30E-05 1/K Length L 60 to 100, s 1/K 2 95% No 5.4/2 range from 1.1E- 07 to 1.6E-07 Temperature 15 C to 25 C 5.4/2 100 1000 Q[22, 0.066L ], L in nm 2 95% No 5.4/3 200 1000 Q[30, 0.L ], L in nm 2 95% No 5.4/4 0.5 400 µm 0.02 µm 2 95% No 4.22/1 0 50 m Support multiple catenary, 0.4 m distance Q[13.4, 2.6L ], L in m µm 2 95% No 5.23/2 (surveyor, engineer) tape, steel: line spacing L 50 100 m Support multiple catenary, 0.4 m distance Q[132, 2.6(L - 50 m)], L in m µm 2 95% No 5.23/3 (surveyor, engineer) tape, invar: line spacing L 0 50 m Support multiple catenary, 0.4 m distance Q[13.4, 0.72L ], L in m µm 2 95% No 5.23/4 The BIPM key comparison database, Juin 2018 2/13
(surveyor, engineer) tape, invar: line spacing L 50 100 m Support multiple catenary, 0.4 m distance Q[41, 0.72(L - 50 m)], L in m µm 2 95% No 5.23/5 Precision line scale, steel: line spacing L Precision line scale, invar: line spacing L 0.1 4 m 0.1 4 m Q[5.8, 1.8L ], L in m Q[5.8, 0.4L ], L in m µm 2 95% No 5.23/6 µm 2 95% No 5.23/7 ar encoders: line spacing 1-D vacuum comparator 10 610 Low thermal expansion substrate Q[1, 0.002L ], L in nm 2 95% No 5.21/3 Approved on19 May 2007 Precision line scale: line spacing Photomask or wafer: linewidth 1-D vacuum comparator, photoelectric microscope Scanning electron microscope and interferometer 0.01 610 flatness < 1 µm, low thermal expansion substrate Q[9, 0.002L ], L in nm 2 95% No 5.21/4 0.2 1000 µm Top linewidth 0.015 µm 2 95% No 5.22- BS/10 Approved on19 May 2007 1-D grating: mean pitch Laser diffractometer 0.14 4 µm Grating area > 0.1 2 20 pm 2 95% No 4.22/2 2-D grating: mean pitch Laser diffractometer 0.14 4 µm Grating area > 0.1 2 20 pm 2 95% No 4.22/2 Diameter Diameter External cylinder (plug, piston, pin): L External cylinder (plug, piston, pin): L 1-D comparator and contacting probe 1-D comparator and 2 contacting probes 0.5 190 2 185 Q[48, 0.4L ], L in Q[10, 0.1L ], L in nm 2 95% No 5.31/4 nm 2 95% No 5.31/5 The BIPM key comparison database, Juin 2018 3/13
Diameter Diameter Diameter Angle by circle dividers Angle by circle dividers Angle by circle dividers Angle by circle dividers Angle Angle Angle Angle cylinder (ring): L cylinder (ring): L External sphere: L Optical polygon: face angle Index table: index angle Rotary encoder scale: position angle Rotary table: position angle Autocollimator: error of indicated angle Electronic level: error of indicated inclination angle Angle block: included angle 90 square: squareness 1-D comparator and contacting probe 1-D comparator and 2 contacting probes 1-D comparator and 2 contacting probes Angle comparator and autocollimator Cross calibration versus angle comparator or polygon and autocollimator 2 200 10 170 2 100 Q[48, 0.4L ], L in Q[14, 0.1L], L in Q[10, 0.1L ], L in nm 2 95% No 5.31/6 nm 2 95% No 5.31/7 nm 2 95% No 5.31/8 3 72 faces 0.03 " 2 95% No 5.22-BS/2 0 360 0.2 " 2 95% No 5.22-BS/4 Angle comparator 0 360 0.01 " 2 95% No 5.22-BS/5 Cross calibration versus angle comparator or polygon and autocollimator Angle comparator 0 360 Step size 5 0.1 " 2 95% No 5.22-BS/6 instrument specific " 1 or 2 axes of measurement 0.01 " 2 95% No 5.22-BS/8 Autocollimator 0 1000 " 0.3 " 2 95% No 5.22-BS/9 Angle comparator and autocollimator Polygon, autocollimator and precision straightline motion 0 180 0.05 " 2 95% No 5.22-BS/1 0 360 Orientation horizontal 0.2 " 2 95% No 5.22-BS/3 Size up to 1000 5.22-BS/3 The BIPM key comparison database, Juin 2018 4/13
Angle 90 cylinder square: squareness Reversal method with reference on MFU8-PTB 0 500 µm/m Length up to 360 3 " 2 95% No 5.31/9 Diameter up to 185 5.31/9 Flatness standard Optical flat - flatness deviation over whole Tolanski multiple beam Fizeau interferometer 0 5 µm Diameter of artefact 10 to 250 10 nm 2 95% No 4.21/1 Roundness Roundness Straightness Straightness Straightness Straightness Ring, plug, sphere, hemisphere: roundness R Magnification standard (e.g. flick standard): roundness R Straight edge: straightness S Straight edge with 2 parallel faces: parallelism P Cylindrical straightness standard: straightness S Cylindrical straightness standard: parallelism P Depth standard (ISO 5436-1 type A): profile depth Stylus-on-spindle roundness instrument Stylus-on-spindle roundness instrument Reversal method with reference on MFU8-PTB Reversal method with reference on MFU8-PTB Reversal method with reference on MFU8-PTB Reversal method with reference on MFU8-PTB Interference microscope 0 400 µm Diameter 1 to 100 2 400 µm Diameter 5 to 100 0 100 µm Length L up to 400 0 100 µm Length L up to 400 0 100 µm 0 100 µm 0.01 10 µm External length L length L External length L length L depth of profile, Pt up to 400 Q[6, 10R ], R in µm Q[6, 10R ], R in µm Q[50, 0.4L, 10S ], L in, S in µm Q[70, 0.6L, 14P ], L in, P in µm Q[50, 0.4L, 10S ], L in, S in µm nm 2 95% No 5.31/13 nm 2 95% No 5.31/16 nm 2 95% No 5.31/17 nm 2 95% No 5.31/18 nm 2 95% No 5.31/19 up to 200 5.31/19 up to 400 Q[70, 0.6L, 14P ], L in, P in µm nm 2 95% No 5.31/20 up to 200 5.31/20 ISO 4287 Q[6.5, 1.5Pt ], Pt in µm nm 2 95% No 5.17/2 The BIPM key comparison database, Juin 2018 5/13
Depth standard (ISO 5436-1 type A) Roughness standard (ISO 5436-1 type C): ISO roughness parameters Roughness standard (ISO 5436-1 type C, D): ISO roughness parameters Thread plug, plain: pitch Thread plug, plain: lead, pitch Thread plug, plain: flank angle Thread plug, tapered: pitch Thread plug, tapered: lead, pitch Thread plug, tapered: flank angle SFM 0.005 5 µm Groove depth d ISO 5436-1 Stylus instrument, ISO 3274 Stylus instrument, ISO 3274 25 2500 µm RSm 0.02 4 µm Average parameters, Ra and Rq ISO 4287, ISO 4288, ISO 11562 ISO 4287, ISO 4288, ISO 11562 Q[1, 0.5d ], d in µm nm 2 95% No 5.14/3 0.5 µm 2 95% No 5.17/3 Q[0.5, 10Ra ], Ra in µm nm 2 95% No 5.17/4 substitution 5 700 Pitch 0.75 to 6 2.0 µm 2 95% No 5.32/1 0.75 6 Major 5 to 700 0.5 µm 2 95% No 5.32/2 substitution 3 90 Major 5 to 700 2.0 ' 2 95% No 5.32/3 substitution 5 700 Pitch 0.75 to 6 2.0 µm 2 95% No 5.32/4 0.75 6 Major 5 to 700 0.5 µm 2 95% No 5.32/5 substitution 3 90 Major 5 to 700 2.0 ' 2 95% No 5.32/6 Thread plug, tapered: cone angle Thread ring, plain: pitch Thread ring, plain: lead, pitch Thread ring, plain: flank angle 0 15 Major 5 to 700 4 '' 2 95% No 5.32/7 substitution 5 600 Pitch 0.75 to 6 2.0 µm 2 95% No 5.32/8 0.75 6 Minor 5 to 600 0.5 µm 2 95% No 5.32/9 substitution 3 90 Minor 5 to 600 2.0 ' 2 95% No 5.32/10 The BIPM key comparison database, Juin 2018 6/13
Thread ring, tapered: pitch Thread ring, tapered: lead, pitch Thread ring, tapered: flank angle substitution 5 600 Pitch 0.75 to 6 2.0 µm 2 95% No 5.32/11 0.75 6 Minor 5 to 600 0.5 µm 2 95% No 5.32/ substitution 3 90 Minor 5 to 600 2.0 ' 2 95% No 5.32/13 Complex geometry Film thickness Thread ring, tapered: cone angle Ball plate: 2D centre coordinates Ball bar: centre spacing L software: Gaussian associated features for least square for circle, sphere, cylinder, plane, cone Film thickness gauge Gauge blocks: thermal expansivity a Gauge blocks: thermal expansivity 0 15 Minor 5 to 600 4 " 2 95% No 5.32/14 with laser interferometer and reversal technique with laser interferometer Ball plate size < 960 x 960 Ball bar size 10 to 960 Q[0.4, 0.5L ], L center distance in m Q[0.4, 0.5L ], L in m µm 2 95% No 5.32/19 µm 2 95% No 5.32/20 Software test 2 95% No 5.32/21 Ball plate calibration sphere SFM 0.005 5 µm Interferometry, exact fractions Mechanical comparison size -2.0E-05 2.0E-05 1/K Length L < 1000 x 1000 x 1000 60 to 1000 Temperature 15 C to 25 C 5 to 1000 0.9E-05 1.3E-05 1/K Length L Temperature 15 C to 25 C Q[0.6, 1.0L ], L length in m Q[1, 0.5h ], h thickness in µm Q[2.4E-06/L, 2.2E-09, 4.6E- 04a ], L in, a in 1/K Q[2.4E-05/L, 2.7E-08], L in µm 2 95% No 5.32/22 nm 2 95% No 5.14/1 1/K 2 95% No 5.4/5 1/K 2 95% No 5.4/6 The BIPM key comparison database, Juin 2018 7/13
Film thickness Depth standard (ISO 5436-1 type A): groove depth Depth standard (ISO 5436-1 type A): groove depth Roughness standard (ISO 5436-1 type C, D): ISO roughness parameters Roughness standard (ISO 5436-1 type D): ISO roughness parameters Film thickness gauge Precision line scales: mean pitch p Grating scales: mean pitch p Grating scales: orthogonality Gauge block: length difference of gauge block pairs Stylus instrument, ISO 3274 Interference microscope Stylus instrument, ISO 3274 Stylus instrument, ISO 3274 0.01 5 0.01 10 µm 0.1 20 µm 0.1 20 µm Groove depth, d Groove depth, d Peak parameters, Rz, Rp, Rv, Rt, Rz1max Rk parameters, Rk, Mr1, Mr2, Rpk,Rvk SEM 1 50 µm Thickness h Metrological SFM 50 50000 nm Metrological SFM (50x50) (50000 x 50000) ISO 5436-1 Q[22, 36d ], d in nm 2 95% No 5.11/1 ISO 5436-1 Q[2, d ], d in µm nm 2 95% No 5.17/1 ISO 4287, ISO 4288, ISO 11562 ISO 13565-1, ISO 13565-2 Q[3, 10Rz ], Rz in µm Q[3, 10Rz ], Rz in µm (25 nm + 5E- 03h ), h in µm (0.002 + 3E- 05p ), p in nm nm 2 (0.002 + 3E- 05p ), p in nm nm 2 95% No 5.17/5 nm 2 95% No 5.17/6 nm 2 95% No 5.14/2 nm 2 95% No 5.15/1 nm 2 95% No 5.15/2 Metrological SFM 89 90 0.0024 2 95% No 5.15/3 Interferometry, exact fractions 0 20 µm Length 0.5 to 100 10 to 14 nm 2 95% No 5.4/7 The BIPM key comparison database, Juin 2018 8/13
Specimen with parallel end faces (e.g. gauge blocks) thermal expansivity, length stability Interferometry, exact fractions -1.0E-04 1.0E-04 1/K Length L 0.5 to 400 2Q[5E-11/L, 1E- 05a /L], L in m, a in 1/K 1/K 2 95% No 5.4/8 Straightness Straight edge: straightness S Reversal method with precision PTB straight guide 0 100 µm Orientation Parallelism less than 10 µrad Temperature 10 C to 30 C horizontal length up to 1000 Q[50, 0.4L, 10S ], L in, S in µm nm 2 95% No 5/0119 Film thickness SiO2/Si thickness Ellipsometer 6 1000 nm 0.7 to 2.2 nm 2 95% No 5.14/3 Film thickness Nanoparticle size Thin layer on reflecting surface Mean nanoparticle of monodisperse spherical particles Involute gear: profile slope deviation X-ray reflectometer 2 200 nm 0.24 to 2.0 nm 2 95% No Small-Angle X-ray Scattering (Synchrotron radiation) 3 300 nm Mean -370 +370 µm nanoparticles in suspension PTB_7.1_ 1.11 1 % 2 95% Yes 7.1/ 25 to 400 0.7 to 1.1 µm 2 95% No 5.32/15 03 November 08 October 20 08 October 20 22 2015 ISO 1328 module 70 ) The BIPM key comparison database, Juin 2018 9/13
Involute gear: profile form deviation Involute gear: profile deviation, total Involute gear: helix slope deviation 0 +490 µm 0 +610 µm 25 to 400 0.5 µm 2 95% No 5.32/15 25 to 400 0.9 to 1.4 µm 2 95% No 5.32/15-180 +180 µm Helix angle 0 to 45 0.7 to 1.3 µm 2 95% No 5.32/16 25 to 400 ISO 1328 module 70 ) ISO 1328 module 70 ) ISO 1328, facewidth 1000 ) The BIPM key comparison database, Juin 2018 10/13
Involute gear: helix form deviation Involute gear: helix deviation, total Involute gear: single pitch deviation 0 +220 µm Helix angle 0 to 45 0.6 µm 2 95% No 5.32/16 25 to 400 0 +290 µm Helix angle 0 to 45 1.0 to 1.5 µm 2 95% No 5.32/16 0 +380 µm 25 to 400 25 to 400 0.5 µm 2 95% No 5.32/17 ISO 1328, facewidth 1000 ) ISO 1328, facewidth 1000 ) ISO 1328, module 70 ) The BIPM key comparison database, Juin 2018 11/13
materials Involute gear: cumulative pitch deviation, total Standard particle, particle size d Algorithms for calculating minimum-zone associated features for 2D-circle, 2Dline, plane, sphere and cylinder 0 +820 µm Scanning Electron Microscopy in Transmission Mode (TSEM) Software test on data in the reference volume [- 500, 500 ]³ 7 300 nm Mean 25 to 400 0.5 µm 2 95% No 5.32/17 (2 + 0.02d ), d in nm nm 2 95% No 4.22/3-500 500 Size/Position 8E-11 2 95% Yes 5.32/21 ISO 1328, module 70 ) Algorithms for calculating minimum-zone associated features for 2D-circle, 2Dline, plane, sphere and cylinder Software test on data in the reference volume [- 500, 500 ]³ -500 500 Form deviation 2E-11 2 95% Yes 5.32/21 Algorithms for calculating minimum-zone associated features for 2D-circle, 2Dline, plane, sphere and cylinder Software test on data in the reference volume [- 500, 500 ]³ -500 500 Orientation 2E- rad 2 95% Yes 5.32/21 The BIPM key comparison database, Juin 2018 /13
Angle Clinometer: error of indicated inclination angle Comparison with optical dividing head -90 90 5 " 2 95% No 5/05 10 October 2017 The BIPM key comparison database, Juin 2018 13/13