1

Shutdown the system and stop the gas supply for detectors.

2

Loosen the knurled screw and remove the FPD cover.

3

Loosen the 2 photomultiplier unit fixing knurled screws.

4

Slowly pull the photomultiplier unit out to remove it.

Cover the photomultiplier receiver with aluminum foil etc. to avoid exposure to intense light.

5

Remove the cooling duct.

6

Undo the 2 body section setscrews.

7

Pull the body section out upwards with the body section fixing plate.

8

Loosen the cooling fin fixed nut and remove.

9

Check the lens unit visually and, if dirty, either clean or replace it.

Also replace the O-ring of the lens unit if it has deteriorated.

Lens P/N 221-48575
O-ring P/N 036-11022-84

10

Once the lens and O-ring have been set in place, tighten the nut by hand and attach the cooling fin.

11

Insert the body section with the body section fixing plate into the nozzle base.

12

Fix the body section with the 2 screws.

13

Attach the cooling duct.

14

Put back the photomultiplier unit slowly.

15

Tighten the photomultiplier unit fixing knurled screws to fix the photomultiplier unit.

Check to ensure that it has been fixed tight.

16

Put back the cover and tighten the knurled screw.

17

Start up the system.