Inficon Transpector CPM User Manual

6–10
Transpector CPM Operating Manual
filament would stay on and react with the oxygen, producing relatively volatile
tungsten oxides, until the filament diameter had been reduced to the point where
the tension on the wire was sufficient to cause the wire to pull apart.
Figure 6-2 depicts a CPM over-pressure trip calculation. The total pressure current
curve after 5E-1 is due to the pure collisional scattering. Without collisional
scattering, it would be linear. The point where the CIS total pressure current and
DAC line meet is called the over-pressure trip point. When the total pressure
current exceeds the DAC line (Region II) the filament is turned off.
NOTE: In Region II, there is a six second delay in turning emission on and off.
At 5 Torr in Region III, there is no overpressure and no emission error, but the
filament would last only hours. At 100 Torr, the filament would be destroyed
instantly.
Figure 6-2 CPM over-pressure trip calculations
CPM Over-pressure Trip Calculations
1.E-11
1.E-10
1.E-09
1.E-08
1.E-07
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E-07 1.E-06 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02
Ion Source Total Pressure (Torr)
Ion Current (Amps)
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
Filament Lifetime in O
2
/H
2
O (s)
Collected DAC = 150 Lifetime (s)
CIS total pressure current
filament will stay
on in this region
Region I
filament will turn
off in this region
Region II
filament
will stay
on and be
destroyed
Region III
Filament Lifetime(s)

Inficon Transpector CPM Specifications

General

Brand	Inficon
Model	Transpector CPM
Category	Industrial Equipment
Language	English