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

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.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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)

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)

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

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

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

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

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

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

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

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)

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

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

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

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!

Remove exit slit Remove the exit slit from the source base

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

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

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