1. Ion source maintenance on the MAT 253
Disassembling the ion source…
First draft by Anthony L Michaud

2. Use the manual!
This presentation is NOT a replacement for the manual. Use the manual as much as possible! This presentation is intended to make it a little easier to see what each part looks like and to add to the manual.
Schematics for the ion source are provided in section 8 of the manual
Print out all pages from 8-48 to 8-67
Turn off the mass spectrometer first by shutting off the pumps using the switches on the instrument
Once you are ready to start work on the instrument, turn off the mains switch behind the instrument to shut off all electronics (just ensuring that you don’t get a 10KV zap)
Note: if you have other instruments connected to the MAT 253 (such as the TC/EA), they should be in a “safe” state before shutting off the electronics. If not, then run an extension cord from the deltaplus over to the device and connect it temporarily to the deltaplus.

3. Plan this out. Use a clean surface and draw everything
Plan this out!!! Use a clean surface and draw everything! Write down a step by step detailed sequence of what you do!
Clean surface for all parts. Can draw on surface. Very nice!
Outline of parts and description
Step by step detailed account of work

4. Remove cover plates
Remove the screws mounting the source lead cover in place
These are flat head screws, two each holding each cover half to the source and two more holding the cover pieces together

5. Remove the cover plates
The cover plates are fairly tightly held in place. You may need to pry them off gently with a screw driver
Underneath the cover are the source leads, each insulated with a teflon sheet

6. Remove the leads
Warning! The mains should be OFF so that you don’t risk getting shocked!
Slide the teflon cover off of a lead
Use a 1.5mm allen wrench to loosen the lead and then slide the lead connector off of the source feed through pin

7. Pin identification
Use the schematic from page 8-54 of the manual to identify the pins
Note that the manual does a poor job of identifying these so see the next slide for detail

8. Pin identification K+/K- pins for the filament 1: Trap
2: Ionization housing (ion box)
3: extraction plate
4: empty – nothing connected here
5: shield
6: lens (positioned opposite of the gas inlet)
7: lens (positioned on same side as gas inlet)
8: r-delfection
9: z-deflection (filament side)
10: z-deflection (trap side)
11: einzel lens
12: einzel lens (double check this)
13: halogen lights
14: halogen lights
15: halogen lights

9. Removing the source
Use a 13mm wrench to loosen each bolt on the source
Loosen bolts in a criss-cross fashion
Initially, only loosen each bolt by about 1/8 of a turn so as to evenly loosen the entire source
Hint: leave one bolt on top and one on bottom for last so that you can support the source with one hand while removing these bolts with the other

10. Ion source
Einzel lens stack
Sulfur window
Place the ion source on the stand (be sure that no weight is put on the feedthrough pins!!!)
Observe the connections, plates, gas inlet, sulfur window, etc.
Gas inlet
Magnet over filament

11. Ion Source Note where leads are connect and what they are connected to
Einzel lens stack
Sulfur window
Note where leads are connect and what they are connected to
Ceramic guide posts
Gas inlet
Magnet over filament

12. Ion source Turn the source and see the other leads Einzel lens stack
Trap side magnet
Gas inlet
Halogen bulbs
Steel mounting posts

13. Ion source Observations Einzel lens stack Einzel lens lead
Sulfur window
Observations
Exit slit
Filament side magnet
Trap side magnet
Ionization housing

14. Ion source Observations Einzel lens stack Einzel lens lead
Trap side magnet
Filament side magnet
Filament leads
Gas inlet

15. Disconnect filament
Use a flat head screw driver to disconnect the filament leads from the feedthrough post
Then remove screws holding the filament magnet in place
Finally, remove screws holding filament in place

16. Disconnect leads
Use pliers (small ones) to retract each lead from the pin it is connected to
DO NOT remove leads from the feedthrough pins on the source flange

17. Remove the source body
After removing all of the leads, double check that they really are ALL disconnected
Use a larger flat head screw driver to remove the two screws from the steel mounting posts (sorry, no picture)
Remove the source body and place it gently onto a clean work surface

18. Remove Einzel lens leads
Use the needle nose pliers to remove the leads from each einzel lens
See manual, p 8-66, fig 8-12

19. Remove Ground Plates
Remove the 4mm nuts and washers on top of the einzel lens stack
Remove the top grounding plates (these are stamped “5” on the side facing the ionization housing)

20. Remove Einzel lenses Remove the outer ceramic spacer tube
Note that groove in ceramic spacer is facing ionization housing
Remove Einzel lenses (these are stamped “4” on the side facing the ionization housing)

21. Remove grounding plates
Remove the second set of ceramics (narrow tube and shorter wide space)
Note again that grooves in ceramics are facing ionization housing
Remove the second pair of grounding plates
Einzel lens stack is now completely removed

22. Remove magnet and trap
Remove the magnet covering the trap (electron collector)
Remove the trap

23. Loosen ceramic posts
Note where the ceramic post protrude through the top (side opposite the ionization housing) of the ion source
Use a small screw driver (if necessary) to loosen the threaded sleeves on the ceramic posts (these provide tension to hold pins in the bottom of the posts on the ion box side)
Use pliers to remove the pins in the bottom of the ceramic posts

24. Dissasembly
Slide the ceramic posts out about 1 cm at a time in order to disassemble the ion source piece-wise

25. Put source on its side!
Important Note: The first time I took the source apart was not the best way to do it! Do not place the ion source in an upright position as I did in the top picture here. There is a quartz tube that transfers gas from the gas inlet to the ionization housing and it is VERY FRAGILE! I chipped mine by placing the source upright. Put the source on its side
The steps that follow are given in the better order (not the order I followed the first time)
Fragile quartz tube

26. Remove gas inlet and ion box
Remove the post holding the gas inlet
Retract the fragile quartz tube from the ionization housing
Remove the ionization housing

27. Ground plate and quartz spacer
Remove the cover plate (stamped “9” on the side facing the ion box)
Remove the narrow quartz spacer ring

28. Extraction plate and spacer
Remove the extraction plate (stamped “8” on side facing ion box)
Remove the quartz spacer ring (last item shown in Fig 8-10 of manual)

29. Shield and spacer
Remove the shield (stamped “7” on side facing ion box)
Remove quartz spacer

30. Lenses Remove lenses (two have circles)
These are stamped “6” on side facing ion box
Note the orientation of the lead pins on each lens: one faces straight out and the other is at a 45 degree angle

31. Quartz spacer and r-deflection plate
Remove the quartz spacer
Remove the r-deflection plate (stamped “5” on side facing ion box)

32. Z-deflection and ground plates
Remove quartz spacer
Remove the assembly containing ground plates (these are connected by a U-shaped lead) and the z-defection plates
Disassemble this assembly, take pictures, and improve this slide!

33. Remove exit slit
Remove the exit slit from the source base

34. Replace halogen bulbs Replace the halogen bulbs
Note: they are cheap so you should replace them even if they look ok

35. Cleaning
I only use a glass brush to remove all residues from the lenses. I have not cleaned the quartz spacers or ceramics. In general, quartz spacers can be cleaned by sonication in acetone.
Be very careful about cleaning the ceramics. You should check on isogeochem and also with Thermo about heat-treatment to clean them if you think it is necessary

36. Improve this slideshow
Upon the next ion source cleaning, many pictures should be taken and this slideshow should be improved.
Add pictures of glass brush use
Add pictures showing removal of ion source from steel mounting posts
Add more