1. BASIC VACUUM PRACTICE

2. To move a particle in a (straight) line over a large distance
Why is a Vacuum Needed?
To move a particle in a (straight) line over a large distance
(Page 5 manual)

3. Why is a Vacuum Needed? To provide a clean surface Atmosphere
(High)Vacuum
Contamination
(usually water)
Clean surface
To provide a clean surface

4. HOW DO WE CREATE A VACUUM?

5. VACUUM PUMPING METHODS
Sliding Vane
Rotary Pump
Molecular
Drag Pump
Turbomolecular
Pump
Fluid Entrainment
VACUUM PUMPS
(METHODS)
Reciprocating
Displacement Pump
Gas Transfer
Vacuum Pump
Drag
Entrapment
Positive Displacement
Kinetic
Rotary
Diaphragm
Piston
Liquid Ring
Piston Pump
Plunger Pump
Roots
Multiple Vane
Dry
Adsorption
Cryopump
Getter
Getter Ion
Sputter Ion
Evaporation
Ion Pump
Bulk Getter
Cold Trap
Ion Transfer
Gaseous
Ring Pump
Turbine
Axial Flow
Radial Flow
Ejector
Liquid Jet
Gas Jet
Vapor Jet
Diffusion
Ejector Pump
Self Purifying
Diffusion Pump
Fractionating
Condenser
Sublimation

6. BAROMETER 10.321 mm 760 mm 29,9 in WATER MERCURY
Mercury: times heavier than water: Column is x shorter :
10321 mm/13.58=760 mm (= 760 Torr)
10.321 mm
760 mm
29,9 in
WATER
MERCURY
(Page 12 manual)

7. AT SEA LEVEL, 0O C AND 45O LATITUDE
PRESSURE OF 1 STANDARD
ATMOSPHERE:
760 TORR, 1013 mbar
AT SEA LEVEL, 0O C AND 45O LATITUDE

8. Atmospheric Pressure (Standard) =
Pressure Equivalents
Atmospheric Pressure (Standard) =
14.7
29.9
760
760,000
101,325
1.013
1013
gauge pressure (psig)
pounds per square inch (psia)
inches of mercury
millimeter of mercury
torr
millitorr or microns
pascal
bar
millibar

9. THE ATMOSPHERE IS A MIXTURE OF GASES
PARTIAL PRESSURES OF GASES CORRESPOND TO THEIR RELATIVE VOLUMES
GAS
SYMBOL
PERCENT BY
VOLUME
PARTIAL PRESSURE
TORR
PASCAL
Nitrogen
Oxygen
Argon
Carbon Dioxide
Neon
Helium
Krypton
Hydrogen
Xenon
Water N2 O2 A
CO2 Ne He Kr H2 X
H2O 78 21
0.93
0.03
0.0018
0.0005
0.0001
Variable
593
158
7.1
0.25
1.4 x 10-2
4.0 x 10-3
8.7 x 10-4
4.0 x 10-4
6.6 x 10-5
5 to 50
79,000
21,000
940 33
1.8
5.3 x 10-1
1.1 x 10-1
5.1 x 10-2
8.7 x 10-3
665 to 6650
(Page 13 manual)

10. VAPOR PRESSURE OF WATER AT VARIOUS TEMPERATURES
T (O C)
100 25
-40
-78.5
-196
P (mbar)
1013 32
6.4
0.13
6.6 x 10 -4
10 -24
(BOILING)
(FREEZING)
(DRY ICE)
(LIQUID NITROGEN)
(Page 14 manual)

11. (Page 15 manual)

12. Vapor Pressure of some Solids
(Page 15 manual)

13. PRESSURE RANGES RANGE ROUGH (LOW) VACUUM HIGH VACUUM ULTRA HIGH VACUUM
759 TO 1 x (mbar)
1 x TO 1 x (mbar)
LESS THAN 1 x (mbar)
(Page 17 manual)

14. GAS FLOW CONDUCTANCE
(Page 24 manual)

15. Viscous and Molecular Flow
Viscous Flow
(momentum transfer
between molecules)
Molecular Flow
(molecules move
independently)

16. FLOW REGIMES Viscous Flow:
Distance between molecules is small; collisions between
molecules dominate; flow through momentum transfer;
generally P greater than 0.1 mbar
Transition Flow:
Region between viscous and molecular flow
Molecular Flow:
Distance between molecules is large; collisions between
molecules and wall dominate; flow through random motion;
generally P smaller than 10 mbar -3
(Page 25 manual)

17. MOLECULAR DENSITY AND MEAN FREE PATH
1013 mbar (atm)
1 x mbar
1 x mbar #
mol/cm3
MFP
3 x
(30 million trillion)
4 x
(40 trillion)
4 x 10 7
(40 million)
2.5 x in
6.4 x mm
2 inches
5.1 cm
31 miles
50 km

18. FLOW REGIMES Mean Free Path Characteristic Dimension Viscous Flow:
is less than 0.01
Mean Free Path
Characteristic Dimension
Transition Flow:
is between 0.01 and 1
Mean Free Path
Characteristic Dimension
Molecular Flow:
is greater than 1

19. Conductance in Viscous Flow
Under viscous flow conditions doubling the
pipe diameter increases the conductance
sixteen times.
The conductance is INVERSELY related to
the pipe length
(Page 28 manual)

20. Viscous Flow (Long Round Tube; air)
C = 1.38 x 102 x d4 x P1 + P2 (l/sec) 2 l
d = diameter of tube in cm
l = length of tube in cm
P1 = inlet pressure in torr
P2 = exit pressure in torr

21. Viscous Flow (Long Round Tube; nitrogen)
EXAMPLE:
d = 4 cm P1 = 2 torr
l = 100 cm P2 = 1 torr
C = 138 x d4 x P1 + P2 (liter/sec) 2 l
C = 138 x x 3 (liter/sec)
100
C = (liter/sec)

22. Conductance in Molecular Flow
Under molecular flow conditions doubling
the pipe diameter increases the conductance
eight times.
The conductance is INVERSELY related to
the pipe length.

23. Conductance in Molecular Flow (Long Round Tube)
C = x d3 x T M l
(l/sec)
d = diameter of tube in cm
l = length of tube in cm
T = temperature (K)
M = A.M.U.

24. Conductance in Molecular Flow (Long Round Tube)
EXAMPLE:
T = 295 K (22 OC)
M = 28 (nitrogen)
C = x d3 x T M l
(l/sec)
= x d3 x
295 28
= x d3

25. EXAMPLE:
T = 295 K (22 OC) d = 4 cm M = 28 (nitrogen) l = 100 cm
C = x d3 x T M l
(l/sec)
= x d3 x
295 28
= x d3
= x 0.64
= 7.9 (l/sec)

26. Series Conductance RT = R1 + R2 1 = 1 + 1 1 = C1 + C2 CT C1 C2 C1 CT
SYSTEM
1 = CT C1 C2 C1
1 = C1 + C2 CT
C1 x C2 C2
CT = C1 x C2
C1 + C2
PUMP
(Page 29 manual)

27. GAS LOAD (Q) IS EXPRESSED IN:
Permeation
Outgassing
Real
Leaks
Diffusion
Virtual
Backstreaming
GAS LOAD (Q) IS EXPRESSED IN:
mbar liters per second

28. Pumpdown Curve 10+1 10-1 Volume 10-3 10-5 Pressure (mbar)
Surface Desorption
10-7
Diffusion
10-9
Permeation
10-11
10 1
10 3
10 5
10 7
10 9
10 11
10 13
10 15
10 17
Time (sec)

29. Roughing Pumps 2
(Page 39 manual)

30. VACUUM PUMPING METHODS Positive Displacement
VACUUM PUMPS
(METHODS)
Gas Transfer
Vacuum Pump
Entrapment
Vacuum Pump
Positive Displacement
Vacuum Pump
Kinetic
Vacuum Pump
Adsorption
Pump
Reciprocating
Displacement Pump
Rotary
Pump
Drag
Pump
Fluid Entrainment
Pump
Ion Transfer
Pump
Cold Trap
Diaphragm
Pump
Liquid Ring
Pump
Gaseous
Ring Pump
Ejector
Pump
Bulk Getter
Pump
Getter
Pump
Piston
Pump
Rotary
Piston Pump
Turbine
Pump
Liquid Jet
Pump
Diffusion
Pump
Getter Ion
Pump
Sublimation
Pump
Multiple Vane
Rotary Pump
Sliding Vane
Rotary Pump
Axial Flow
Pump
Gas Jet
Pump
Diffusion
Ejector Pump
Self Purifying
Diffusion Pump
Evaporation
Ion Pump
Rotary
Plunger Pump
Radial Flow
Pump
Vapor Jet
Pump
Fractionating
Diffusion Pump
Sputter Ion
Pump
Dry
Pump
Roots
Pump
Molecular
Drag Pump
Turbomolecular
Pump
Cryopump
Condenser

31. PUMP OPERATING RANGES Ultra High Vacuum High Vacuum Rough Vacuum
Rotary Vane Mechanical Pump
Rotary Piston Mechanical Pump
Dry Mechanical Pump
Sorption Pump
Blower/Booster Pump
Venturi Pump
High Vac. Pumps
Ultra-High Vac. Pumps
10-12
10-10
10-8
10-6
10-4
10-2 1
10+2
P (mbar)

32. VACUUM SYSTEM USE 9 1 Chamber 8 2 High Vac. Pump 3 Roughing Pump 3a4 5 6 7 8 9
Chamber
High Vac. Pump
Roughing Pump
Foreline Pump
Hi-Vac. Valve
Roughing Valve
Foreline Valve
Vent Valve
Roughing Gauge
High Vac. Gauge 8 1 7 8 5 4 7 2 6 3 3a
(Page 44 manual)

33. Rotary Vane, Oil-Sealed Mechanical Pump
(Page 45 manual)

34. Pump Mechanism

35. How the Pump Works
(Page 46 manual)

36. Pump Down Curves

37. OIL BACKSTREAMING 2
PRESSURE LEVELS: LESS THAN 0.2 mbar

38. The Molecular Sieve/Zeolite Trap
(Page 48 manual)

39. Dry Vacuum Pumps

40. Blower/Booster Pump
(Page 61 manual)

41. One Stage Roots Blower Pump Assembly

42. VACUUM SYSTEM USE 12 11 1 4 3 2 9 10 7 6 8 5 1 Chamber 2 Foreline 3
Roughing Valve
Roughing Gauge
Roughing Pump
Foreline Valve
Foreline Gauge
High Vacuum Valve
Booster/Blower
Vent Valve
High Vacuum Gauge 1 9 3 12 4 11 5 2 6 7 8 10
(Page 62 manual)

43. Piston Type Pump
(Page 51 manual)

44. Piston design
(Page 50 manual)

45. Sorption Pump

46. Sorption Pump Components
(Page 54 manual)

47. Vapor Pressure
(Page 56 manual)

48. Cryo-condensation

49. Cryo-sorption
(Page 55 manual)

50. HIGH VACUUM PUMPS 3
(Page 63 manual)

51. VACUUM PUMPING METHODS Positive Displacement
VACUUM PUMPS
(METHODS)
Gas Transfer
Vacuum Pump
Entrapment
Vacuum Pump
Positive Displacement
Vacuum Pump
Kinetic
Vacuum Pump
Adsorption
Pump
Reciprocating
Displacement Pump
Rotary
Pump
Drag
Pump
Fluid Entrainment
Pump
Ion Transfer
Pump
Cold Trap
Diaphragm
Pump
Liquid Ring
Pump
Gaseous
Ring Pump
Ejector
Pump
Bulk Getter
Pump
Getter
Pump
Piston
Pump
Rotary
Piston Pump
Turbine
Pump
Liquid Jet
Pump
Diffusion
Pump
Getter Ion
Pump
Sublimation
Pump
Multiple Vane
Rotary Pump
Sliding Vane
Rotary Pump
Axial Flow
Pump
Gas Jet
Pump
Diffusion
Ejector Pump
Self Purifying
Diffusion Pump
Evaporation
Ion Pump
Rotary
Plunger Pump
Radial Flow
Pump
Vapor Jet
Pump
Fractionating
Diffusion Pump
Sputter Ion
Pump
Dry
Pump
Roots
Pump
Molecular
Drag Pump
Turbomolecular
Pump
Cryopump
Condenser

52. PUMP OPERATING RANGES Ultra High Vacuum High Vacuum Rough Vacuum
Roughing Pumps
Liquid Nitrogen Trap
Diffusion Pump
Turbo Pump
Cryo Pump
Ion Pump
Tit. Subl. Pump
10-12
10-10
10-8
10-6
10-4
10-2 1
10+2
P (Torr)

53. VACUUM SYSTEM USE 9 8 1 2 3 3a 4 5 6 7 8 9 Chamber High Vac. Pump
Roughing Pump
Fore Pump
Hi-Vac. Valve
Roughing Valve
Foreline Valve
Vent Valve
Roughing Gauge
High Vac. Gauge 1 7 8 5 4 8 2 2 6 3 3a

54. Oil Diffusion Pump

55. Pump Construction
(Page 66 manual)

56. How the Pump Works

57. How the Pump Works

58. Release of Vapors
(Page 67 manual)

59. First stage vapors are separated from others

60. Pumping Speed 10-10 10--3 10--1 Pumping Speed (Air) 1 2 3 4
Inlet Pressure (Torr)
Critical Point
1. Compression Ratio Limit
2. Constant Speed
3. Constant Q (Overload)
4. Mechanical Pump Effect

61. Maximum Tolerable Foreline Pressure
(Page 73 manual)

62. LN2 reservoir with baffles
(Page 78 manual)

63. How the LN2 Trap Works Approximate Vapor Pressure (mbar) Gas
Water (H2O)
Argon (A)
Carbon Dioxide (CO2)
Carbon Monoxide (CO)
Helium (He)
Hydrogen (H2)
Oxygen (O2)
Neon (Ne)
Nitrogen (N2)
Solvents
10-22
500
10 -7
>760
350
760
<10 -10
(Page 79 manual)

64. VACUUM SYSTEM USE
LN2 COLD
TRAP
(Page 80 manual)

65. Turbomolecular Pump (Page 81 manual) INLET FLANGE ROTOR BODY
STATOR BLADES
HIGH PUMPING SPEED
HIGH COMPRESSION
BEARING
EXHAUST
HIGH FREQ. MOTOR
BEARING
(Page 81 manual)

66. Rotor - stator assembly
(Page 82 manual)

67. Pump Operation Molecule V Moving Wall with Speed V
Principle of the Turbomolecular Pump
(Page 83 manual)

68. Roughing through the turbo1 6 7 4 3 2 5 1 2 3 4 5 6
Chamber
Turbo Pump
Roughing Pump
Vent Valve
Roughing Gauge
High Vac. Gauge
(Page 91 manual)

69. Pumping by Cryocondensation

70. Cryosorption in charcoal
(Page 98 manual)

71. Charcoal placement

72. Gauges 5
(Page 123 manual)

73. Gauge Operating Ranges
Ultra High
Vacuum
High Vacuum
Rough Vacuum
Bourdon Gauge
Capacitance Manometer
Thermocouple Gauge
Pirani Gauge
Hot Fil. Ion Gauge
Cold Cathode Gauge
Residual Gas Analyzer
McLeod Gauge
Spinning Rotor Gauge
10-12
10-10
10-8
10-6
10-4
10-2 1
10+2
P (mbar)

74. Bourdon Gauge

75. How the gauge works

76. Thermocouple gauge and Pirani Gauge
Heat Transfer Gauges
Thermocouple gauge
and
Pirani Gauge

77. Thermocouple Gauge

78. How the gauge works

79. Ionization gauges

80. Ionization current is the measure of vacuum

81. Residual Gas Analyzer
QUADRUPOLE
HEAD
CONTROL UNIT

82. How the RGA works

83. RGA SPECTRUM NORMAL (UNBAKED) SYSTEM RELATIVE INTENSITY H2O (A)
MASS NUMBER (A.M.U.)
RELATIVE INTENSITY
NORMAL (UNBAKED)
SYSTEM H2
H2O
N2,, CO
CO2
(A)

84. RGA SPECTRUM N2 SYSTEM WITH AIR LEAK RELATIVE INTENSITY H2O (B) O2 H2
MASS NUMBER (A.M.U.)
RELATIVE INTENSITY
SYSTEM WITH
AIR LEAK H2
H2O N2
CO2
(B) O2

85. LEAK DETECTION 9
(Page 249 manual)

86. Introduction

87. Problems that appear to be Leaks
Outgassing
Leaks
Virtual
Real
Backstreaming
Diffusion
Permeation

88. Trapped Volumes

89. Vented Screw

90. Double O ring sealed shafts
Atmosphere
(760 torr)
Vacuum

91. Differential Pumping
Atmosphere
(1013 mbar)
Vacuum
To Pump
1 mbar

92. PERMEATION LEAKS
Permeation “leaks” are different than real leaks because the only way to stop them is to change to a less permeable material

93. One standard cubic centimeter/sec (std. cc/sec)

94. Leak rate of 1 x 10-1 std cc/sec

95. Leak rate of 1 x 10-3 std cc/sec

96. Leak Rates over Time LEAK RATES 10 -1 STD CC/SEC --- 1 CC/10 SEC
10 -3 STD CC/SEC CC/HOUR
10 -5 STD CC/SEC CC/DAY
10 -6 STD CC/SEC CC/2 WEEKS
10 -7 STD CC/SEC CC/YEAR
10 -9 STD CC/SEC CC/30 YEARS

97. Permeation may occur <1X10-8 std cc/sec

98. Why Helium is used

99. HELIUM Helium is very light and small
Low concentration in air (0.0005%)
Permits dynamic testing
Permits non-destructive testing
Helium is safe

100. CONVENTIONAL LEAK DETECTOR1 2 3 4 5 6 7 8 9 10 11 12
Test Piece
Test Port
High Vac. Pump
Roughing Pump
Fore Pump
RoughingValve
Test Valve
Pump Valve
Spectrometer Tube
Cold Trap
Roughing Gauge
Vent Valve 1 2 12 10 11 9 7 6 8 5 3 4

101. Ion Separation in Magnetic Field
Ion Gauge
Ion Source
To Pre-Amplifier
Magnetic Field
Deflects He Ions
90O, other ions
more or less than
90O.
Lighter ions:
more
Collector
He ions pass
through slit and
are collected
Heavier ions:
less

102. Tracer probe leak detection technique

103. Leak detectors are calibrated with the “permeation leak”