Plasma won't lite when using Ceramic D-Torch

Assembly and Alignment of the Ceramic D-Torch

There is a flat area on the torch and it was not aligned with the igniter wire. By rotating the ceramic outer tube so the flat area aligned with the igniter wire it is commonly found that ignition issues are resolved.

NOTE:  This alignment is in the instructions but it doesn’t clarify the reason or even mention that the flat is where the ignitor wire should contact.

Gas Supply

It is proving more critical to get the gas supply up to specifications. Getting a regulator in place supplying 80 psi (previous pre-install info has requested 87-90 psi) no more than a few feet away from the instrument (2 meters max.) will ensure that the gas box is being delivered what it should be.

Positioning of the Fibre Optic Cables in the Base of the RF Casting

This applies to the new MK2 release.

There is a question over the machined depth of the tapped hole in the front face of the RF housing casting where the socket for the fibre optic is screwed in for a ceramic torch. This will typically require FSE to access the internal RF generator.

Rinse Solution

We have found that the Duo HF Kit's right angle spray chamber neck tends to pool solution and eventually surge or spurt and put the plasma out. To minimize the chance of droplets building up and blowing out the plasma, the problem can be greatly mitigated by adding Decon, Triton X or similar to the rinse solution. We suggest that you use 0.01 – 0.05% Triton X in the rinse. If you use more you can get a foaming problem at the nebulizer and in the spray chamber.

Glass Expansion has recently fixed this issue by going to a curved outlet. The curved outlet eliminates the pooling of droplets that is seen with the right angle outlet.

Gas Flows

Verify proper gas flows, if the in-line gas filter(s) are used, clean or replace them.

In some cases, on disassemble of D-torch, we have found the center tube and fiber optic was wet, apparently the center tube mounting was loose. This also falls in line with having proper gas flows. The torch assembly o-ring seals is very much touchy-feely. Check for argon / air leaks. (leaks contaminate the argon with oxygen and will defeat argon ionization and plasma formation, minor leaks will make it unstable and easy to blow out with sample loading). Snoop all the way to the main argon tank. Look closely at torch assembly alignments and o-ring condition and how seal engagement feels.

CAUTION: When checking torch assembly o-rings always remove center tube FIRST, before attempting to remove torch from the base.

RF Power

In some cases, more intense plasma light for the fiber optic interlock has been improved by bumping up the RF power up to 1350W in the Post Ignition settings. Apparently higher RF power adds plasma intensity or light throughput to the fiber optic just as a quartz outer tube (which typically stays lit better) allows more light throughput to the fiber optic.