PlasmaDetekProducts015

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LINEARITY AND ACCURACY

Stability of the analyzer has been evaluated through a few hours period. Temperature variation has been caused to show the stability

of the reading even with an unstable temperature environment. Those variations have been done on the analyzer itself and not on the

whole system installation which can be different from site to site.

With a deviation of 4.4 Celsius (31.6 to 36 degrees) on a 36 hours period, the reading has moved down from 300 ppb to 280 ppb.

This slight variation gives a 4.5 ppb / Celsius change. Considering that most of the installations are temperature controlled, no

temperature effect will be observed. Moreover, the resolution of the analyzer is 10 ppb and slight temperature variation will not

been seen by the software reading.

Stability has been evaluated on a 24 hours basis with stable environment (figure 13). The drift observed is less than 2 ppb.

Special care has been made on the linearity of the system.

Knowing that existing instruments on the market do not offer

linearity on the complete range of 0-100 ppm, LDetek has

improved its detection system to be sure that working and

calibrating the instrument on the range 0-100 ppm will offer

the best performance.

Figure 12

*Signal versus temperature

Figure 13

*24 hours stability on stable environment

10:04:48 14:52:48 19:40:48 00:28:48

Time

Temp. (Celcius)

0,5

0,45

0,4

0,35

0,3

0,25

0,2

Temperature (Celsius)

Reading (ppm)

0,15

0,1

0,05

Reading (ppm)

05:16:48 10:04:48 14:52:48 19:40:48

On figures 14, calibration of the instrument has been done

with a zero gas going through the LDP1000 gas purifier and

the same dilution system for the different concentrations

measured.

We have also made step changes in low concentration to

show the accuracy of the instrument. Figure 15 demonstrates

that a 10 ppb step change is easily detectable by the

LD8000. Measuring pure gas on the range 0-1 ppm is more

and more popular and such performance is appreciated from

gas producers.

Figure 14

: *

LD8000 linearity on 0-100 ppm range

Note:

This result has been obtained in LDetek facilities with the LDGSS stream selector device with a well purged system according to LDetek standard methods.

60,00

80,00

100,00

120,00

LD8000 ppm reading

0,00

20,00

40,00