The Thyracont SmartLine is available with: i) Pirani, cold cathode or a combined Pirani/hot and Pirani/cold cathode gauge, ii) a variety of mounting flanges, iii) with or without on-device display.
Gauges with on-device displays can be configured with an SLN4 power supply for a cost-effective and compact pressure monitoring solution.
Power supplies:
On-device display versions only need the SLN4, no further cable is needed.
Devices without display need a VD12S2 or VD14S4 (2 or 4 channel respectively) controller. The VD14S4 is new and sacrifices some interfaces to make space for the extra channels. Both VD12S2 and VD14S4 need an interface cable (W1515006) for every device to be controlled. These can control all of the SmartLine gauges, including those with on-device display.
Different Pressure Measurement Gauge Types:
A Pirani pressure measurement sensor is used for rough or pre-vacuum
It functions by maintaining a heated filament at constant temperature in vacuum; the power (current) needed to maintain that temperature is proportional to the vacuum level.
Heat loss is through conduction; conduction is pressure-dependent. The current needed to maintain constant temperature reduces as pressure reduces, pressure calibration is from the current. The lower pressure limit of Pirani technology is in the 10-4mbar range.
An ion gauge is used for high and ultra-high vacuum
A hot cathode ion gauge (Bayard-Alpert) has a filament, high-voltage grid and collector. The filament emits electrons, they accelerate toward the grid and as they travel through the vacuum they collide with the few atoms & molecules present, ionising them (making ions). These ions arrive at the collector, which detects a current proportional to the number of ions arriving. As the current is dependant on the number of ionised molecules arriving at the collector, which itself depends on the number of atoms & molecules present in the vacuum, a lower current indicates a lower vacuum.
Because the filament is ‘heated’ it is considered a hot cathode gauge.
A cold cathode ion gauge (Penning) uses an electrical and magnetic field to ‘pull’ the electrons from the filament, thus it is considered ‘cold’. The ionisation occurs in the electrical and magnetic field, and the collector collects ions and gives a current measurement proportional to the pressure, similarly to the hot cathode gauge.
Ion gauges are available as ‘enclosed’ and ‘nude’ gauges. Nude gauges offer slightly lower lowest pressure, but because ion gauges emit electrons (and some x-rays) they can be incompatible with some sensitive experiments. Thyracont gauges are enclosed so they do not expose the vacuum chamber to the sensor’s emitted particles.
SmartLine also offers a version of a Pirani to be used in aggressive media (corrosive gases). The standard filament is substituted with a chemically more resistant Pt/Rh (Platinum/Rhodium) filament.
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