Hitachi S-4800 manual Evacuating System

Fig. 2-7 shows the block diagram of evacuating system.

MV1	Electron gun
	chamber
MV2	1st
	intermediate
	Chamber
MV3	2nd
	intermediate
	Chamber
	V1
	GV
	SC:Specimen
	chamber

IP1

IP2

IP3

SEC:

Specimen exchange chamber

					PiG-2		LV
		PeG				PiG-1	V3	leak valve
								RP
				TMP	BT V2
								RP
			Fig. 2-7 Evacuating System
IP–1, –2, –3	:	Ion pumps
TMP	:	Turbo-molecular pump
RP	:	Rotary pump
BT	:	Buffer tank
		Keeps back pressure of TMP while RP is evacuating
		specimen exchange chamber.
GV	: Gate valve to isolate specimen chamber and exchange chamber
MV1 to MV3	: Manual valves to evacuate gun and intermediate chambers
V1	: Valve for gun and specimen chamber isolation
V2,V3	:	Vacuum valve
PiG–1	: Pirani gauges to measure vacuum of specimen chamber
PiG–2	: Pirani gauges to measure vacuum of specimen exchange chamber
Pe	: Penning gauge to measure vacuum of specimen chamber
LV	: Leak valve to introduce air into specimen exchange chamber
RP leak valve	:	Leak valve to introduce air into rotary pump

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