Chapter 3 產生真空的辦法 第一節第一節真空幫浦真空幫浦

1 Chapter 3 31 33 1 vacuum pump 2 positive displacement type (rotary pump and scroll pump) kinetic energy type (turbo-molecular pump) (diffusion pump) surface adsorption type pump sorption pump getter pump cryogenic pump cryo pump ion pump)3 ultimate pressure operational pressure range selectivity 4 mercury piston pump mercury piston pump 5 (Rotary pump)

2 Two-stage sliding-vane rotary pump 6 Rotary pump rotor stator sliding vane piston sliding vane piston plunger sliding valve seal sliding-vane oil-sealed rotary pump slidingvane oilsealed rotary pump sliding-vane 7 8 Air Air ballast method 9 scroll pump conjugate 10 11

3 12 diffusion pump diffusion pump random motion pumping fluid pumping fluid nozzle vapour stream fore pump pump 13 boiler jet assembly jet assembly 14 p1 p2 D 15 conductance effective pumping speed

4 16 S S 20 C T 293KM 29 293K M =29 (T/M)(293/29) 17 18 l Ultimate pressure 19 10 10 over load zone over load zone 20 21 M26103 10-3 DC704 silicone oil 10-8 DC705 silicone

5 Oil 4 10-10 DC705 silicone oil 4 1010 Fomblin perfluorinated polyether 9 10-9 Santovac Convelex polyphenyl ether 25 10-9 Santovac Convelex polyphenyl ether 10 Ultralen polyphenyl ether 10-9 Apiezon A hydrocarbon oil 10-5 Apiezon A hydrocarbon oil 10 Apiezon B hydrocarbon oil 6 10-722 getter pump 23 1. 2 2. 3. 4. 4. 5. 6. 7. 8. 24 Getter Getter pumping action ppg (1) chemisorption Chemical absoption (2) getter 25 Getter Pump Getter Pump (1) flash getter dispersal getter d spe sa gette contact getter red phosphor alkali earth metals Ba Ba (2) coating getter ZrH 800 C H Zr (3)

6 Bulk getter nonevapourationgetter non-evapourationgetter solid getter refractory metals Ta Nb Zr Mo W 26 27 sputter ion pump ion pump ion sputtering 28 1 1. 2. 3. 3. 4. 5. 6. 7. 8 8. 9. 10. 10. 29 Ion Pump: Sputtering Sputtering (1) energy threshold gyo d (2) sputtering yield 30 Ion Pump: p diode ion pump : : cylindrical cells anode.

7 Cathode field intensity 1000 2000 field intensity 10002000 3000 5000 31 32 pumping action (1) : () (2) : (3) : (4) : (4) : (5) 33 34 triode ion pump triode ion pump : 5000.

8 Collector 1000 2000 000000 35 36 37 () (2) 38 (1) hot starting (1) hot starting (2) cold starting 39 10 start start glow discharge mV 10 10 10 40 41

9 10 10 42 (A) (B) (C) (C) (D) (E) (E) (F) (G) () (A) (A) (B) (C) 43 cryogenic pump cryopump