1

Shutdown the system and stop the gas supply for detectors.

2

Loosen the 2 collector fixing knurled screws.

3

Detach the collector cover.

Check whether any silica originating from the alkali source has deposited on the inside of the collector cover, blocking the exhaust hole. Increased levels of noise and reductions in sensitivity can result if a lot of silica has been deposited. Wipe away using tissue paper etc.

4

Rotate the FTD collector by hand to loosen it.

5

Detach the FTD collector.

6

Attach the new FTD collector by turning it until it touches. Tightening it too strongly may cause the filament to break, so hand-fix it instead of using a screwdriver.

7

Put back the collector cover.

8

Tighten the collector fixing knurled screws several times, alternating between the top and bottom screws.

The screws must be tightened several times, as tightening one screw may loosen the other. Check to ensure that it has been properly fixed. If this screw is loose, the alkali source will not glow as hot, possibly resulting in reduced sensitivity.

9

Start up the system.