Valco Pulse Discharge Detector
5
The detector can be used in three different versions: HID (helium ionization detector), ECD
(electron capture detector) and PID (photo ionization detector). Installation in the Maxum GC
is possible without further modification, and the detector can only be used in non-hazardous
areas. The PDD uses stable, pulsed DC discharges in helium as the ionization source. The
detector's performance data is equal to or better than that of detectors which use radioactive
ionization sources. Since a radioactive source is not used, the complex directives for radiation
protection need not be observed by the customer.
5.1
PDD Specifications
For information on detector gas-supply requirements. see the Maxum II Official Product
Specifications (A5E03012338001) (
https://support.industry.siemens.com/cs/document/
109742522/maxum-ii-official-product-specifications?lc=en-WW&pnid=17741
). This
publication gives approximate requirements. Specific requirements depend on the application.
Table 5-1
Pulse Discharge Detector, Helium Ionization Mode
Parameter
Value
Target Components
All
Measurement Type
Mass
Smallest Measuring Range (at 60°C oven temperature)
0 to 2 ppm ±5%
Typical Measuring Range (at 60°C oven temperature)
0 to 5 ppm ±5% FS
Dynamic Range
10
3
at fixed attenuation
Linear Range
10
3
at fixed attenuation
Selectivity
None without He and Ne
Temperature Range
70 - 110°C
(higher temperature ranges on request; system
configuration dependent)
Table 5-2
Pulse Discharge Detector, Electron Capture Mode
Parameter
Value
Target Components
Components with electron affinity
Measurement Type
Mass
Smallest Measuring Range (at 60°C oven temperature)
0 to 2 ppm ±5%
Typical Measuring Range (at 60°C oven temperature)
0 to 5 ppm ±5% FS
Dynamic Range
10
3
at fixed attenuation
Linear Range
10
3
at fixed attenuation
Maxum Edition II Detectors
Service Manual, May 2018, A5E42019847001
57