Updated loading procedure for Bravo's Mark V Cell -- AFR 9/22/2023

Important Notes

Refer to the Veeco Mark V 200cc manual (in LASE library) for diagrams and specs!
All loading is now done in the GC glovebag
Have large foil supports in the bag to rest the cell on in order to avoid touching water lines
As of September 2023, the Bravo Mark V cell replaced the PBN spacer that sits inside the heat shielding, outside the metal collet
- This spacer was forced out from behind the shielding wire after the needle valve was not properly seated and was severely cracked
- To reseat and enclose the new spacer, we removed the wire (previously welded to the top of the heat shielding) and crimped the top of the shielding over the spacer to create a small lip to keep it in place
Notes on the flux directioner ("nozzle" in the manual)
- The purpose of the flux directioner is to maximize the flux from the cell since it is not directly pointing at the substrate
- The correct orientation is such that the bottom of the "peace sign" on the flux directioner points in a line along the SF to the substrate
- Bravo has a sharpie mark on both flanges (cell nipple and source port) that indicates where the bottom of the peace sign should be aligned with
- It is preferred that the flux directioner is properly oriented by adjusting the needle valve after replacing it when loading source material, but it can be adjusted by carefully removing the retaining ring (using the sharpest tweezers to fit in the holes) and rotating the directioner
  - The flux director sits on top of a PBN collar inside the needle valve, and is held in place by another PBN collar and retaining ring
  - The retaining ring is very delicate and prone to cracking/chipping
  - If the cell is at a near horizontal, the flux directioner and collar are at risk of falling out once the retaining ring is removed
- The manual has a diagram of the ideal orientation for the flux directioner based on where the cell sits and points on the machine
Decide your source material loading amount, based on whether it will be properly melted (see melting procedure in Mark V manual) and what port it is on

Port Angle	Capacity if pre-melting	Capacity if not pre-melting
12 degrees upward	417 g	200 g
Melt at most upward and then operate at 12 degrees upward	900 g	---

Loading Procedure

P1 removes the Sb cell with the nipple attached and places it in a neutral resting spot (on the foil supports) facing P2
Foil off the Sb port on the GC and remove the gasket from the cell (if applicable)
Refilling should be done with the valve fully open (valve will hit a stop when full travel is reached), to ensure the metal fingers (collet) and the PBN needle valve are fully exposed
1. It is important to come to fully open so the needle valve can be properly seated when putting the assembly back together
2. The travel stops may need to be moved to achieve fully open
Once fully open, P2 can carefully snip the Ta wires (2x) that wrap around the collet fingers inset with UC scissors or snips
1. Ensure the wire does not fall into the cracking head, as this can lead to shorting of the TC or power lines
After removing the wire, P2 can carefully remove the needle valve with UC tweezers and set it in a clean foil boat
1. If the cell is completely empty of source material, the needle valve is expected to come out clean
2. When there is still source material in the cell, the needle valve may come out with Sb flakes/residue on the outside (photos in the share drive)
P2 can insert the UC filling funnel into the cracking head, and begin loading source material
1. The material usually comes in pellet or flake form in small bottles
2. The bottles are UC and P2 can slowly dump in the material while P1 holds the cell up at an angle
3. Pour the material in a bit at a time to ensure it doesn't get stuck in the funnel or crucible. P1 can give the cell a small shake, and P2 should look down the crucible with a light after each filling to ensure no material is getting stuck to the sides
4. The amount of source material to load in this cell is dependent on whether you plan to melt the Sb prior to the campaign, and what port the cell will operate on
After loading, P2 can remove the fill funnel and place the needle valve back into the collet fingers
1. This is the ideal step to make sure the flux directioner is in the correct orientation, because you can simply turn the needle valve appropriately before tying the wire on. This prevents the need for taking apart the needle valve assembly to free the flux directioner. See above notes on orienting the flux directioner correctly
2. Ensure the needle valve is completely seated--expect the fingers to splay slightly and then close back together when the needle valve becomes seated. Refer to the manual to see what a fully seated needle valve looks like
P2 can take UC Ta wire (thick Ta wire is preferred) and tightly wrap it around the inset on the collet to couple the needle valve to the collet
1. 2 separate wires are used to sufficiently enclose the collet
2. Carefully snip the excess wire off and make sure no stray wire falls into the cracking head. Stray wires can short the TC or power lines
Once seated and fastened back together, P1 should fully close and fully open the valve a few times while P2 watches and ensures that everything is seated properly and the PBN spacer is not moving
After this check, P1 can close the valve as needed and replace the travel stop

--AKR 7/14/14

Make sure all necessary tools are in the glovebag prior to beginning loading procedure (refer to glovebagging page).

Sb cell should be pulled with nipple to fit into transit case.

The manual for this procedure is in the share drive:

The full set of pictures is also in a gallery below

P1: Holds Sb cell while P2 removes bolts, installs cell onto mount, loads source material.
P2: Assists P1 (removes/places bolts, hands and opens clean tool boxes to P1, handles clean foil, loosens mount for rotation, removes/places transit case).
P3: Assists P1 and P2.
P4: Maintains glovebag pressure.

Mount holding fixture to BOS movable table with unistrut, c-clamps, and four 1/4-28 bolts. Make sure the head is UHV clean and wrapped in clean foil while mounting.
1. Mounting fixture in glovebag
Unwrap clean foil from mounting fixture head and place four 5/16-24 (conflat) studs. If any of the studs don't go into the tap easily, try another tap as some are sticky.
If the gasket stayed in place when removing the cell, you can use that gasket to mount the cell to the mounting fixture. Otherwise, place a new or used gasket onto the mounting fixture using gasket clips. One of the gasket clips may be tricky to get into place as one of the water feedthroughs is rather poorly placed.
1. Mounting fixture head with studs and gasket.
If the gasket stayed in place when removing the cell, you can use that gasket to mount the cell to the mounting fixture. Otherwise, place a new or used gasket onto the mounting fixture using gasket clips. One of the gasket clips may be tricky to get into place as one of the water feedthroughs is rather poorly placed.
1. Loosening the bolts on the flange nearest to the cracker
P2: Remove the transit case + nipple.
P3: Cover the transit case with clean foil.
After P2 makes sure the mounting flange is locked in the horizontal position, P1 inserts and mounts the Sb source being careful not to let any in vacuum components touch the mounting head, then and tightens the nuts down (finger tight, or slightly tighter is fine, since this is simply a mechanical mount, and not holding vacuum).
1. P1 securing the cell to the mount while P2 supports it
P1: Remove the first travel stop (there are 3 spaced out around the motor control circumference) to allow the needle to move to the loading position using (3/32" allen wrench). The travel stop should move toward the cell, away from the motor end.
1. From the manual: Removing the travel stop
P1: Turn knob clockwise to extend needle valve to ~ 1 inch past the edge of the tip of the cell.
P2: Loosen mounting fixture to allow for rotation so P1 can rotate the cell to the horizontal position.
P1: After putting on clean gloves, take a small UHV cutter and pliers and very carefully take off the retaining wire assemblies that are positioned in the groove of the needle and collet. Make certain pieces do not fall into the cracking head because the small pieces of wire could short out the power or thermocouple leads. P2 should hold clean foil below the needle valve to catch any fallen pieces of wire.
P1 (clean gloves): Using UHV tweezers, gently pull out the needle valve from the collet and cracking tube and place into clean foil in a safe place where it won't be crushed.
1. P1 removing the valve with clean tweezers
P1 (clean gloves): Place the filling funnel onto the end of the source. The filler tube fits over the end of the cell. Use care when sliding the filler tube the last ½” so not to damage the needle valve seat. This configuration stops any material from accidently falling into the cracking zone or impacting the valve seat.
P1: Rotate the cell to the loading position. The manual suggests 30° above horizontal, but we ended up going closer to 60° from horizontal, because 30° wasn't steep enough to allow the material to fall into the crucible.
P2: Open the outer source material container and drop the inner container into P1's hands while P1 is wearing clean gloves.
P1 (clean gloves): Add material slowly. Pouring material into funnel too fast will result in the funnel clogging. Do not over fill so material is located in the conductance tube. If the funnel does clog, use UHV tweezers to push material into the cell. If this happens several times, you may need to increase the angle from horizontal.
1. Material clogged in the funnel
Using a bright flash light, look into the cell to make sure all of the material is in the crucible and not overflowing into the cracking zone.
P1 (clean gloves): Remove funnel and slide the needle valve back into place. This will expand the fingers of the collet and then snap back into place.
1. Replacing the needle valve
P1 (clean gloves): Take approximately a 6" piece of clean .015 (.02 also works) diameter Tantalum wire. Wrap the wire around the collet fingers and then gently twist the ends of the wire together with your fingers or tweezers. This should begin to draw the collet fingers together around the needle valve.
1. Tightening the wire around the collet
P1 (clean gloves): Trim the excess wire off. Make certain pieces do not fall into the cracking head because the small pieces of wire could short out the power or thermocouple leads. P1 should hold foil under the needle valve to catch fallen pieces of wire.
P1 (clean gloves): Once the wire is trimmed, the twisted pair can be tightened. Do not use excessive force because this could crack the needle valve or break the wire twist.
P1 (clean gloves): Once the wire is tight, cut off all of the twist except for three full turns of the knot. Make certain pieces do not fall into the cracking head because the small pieces of wire could short out the power or thermocouple leads.
P1 (clean gloves): Gently press the twist over to tuck it inside of the groove so it does not extend outside the diameter of the collet.
P1 (clean gloves): Repeat the procedure with a second wire 180° apart from the first.
1. Placing the second wire with the twist 180° from the first wire twist
Turn the valve knob counter clockwise until the travel stops and re-install the travel stop screw that was removed in step 8.
Rotate the cell in preparation for removing the cell from the mounting fixure.
Remove the clean foil from the transit case/nipple. Using gasket clips, place a new silver gasket on the flange of the transit case. Make sure the gasket stays in place by gently rotating the transit case. P3 should hold the transit case while P1 and P2 loosen the nuts on the mounting head.
P1: Remove the cell from the mounting fixture, being careful to not touch the mounting fixture to any in vacuum components.
P1 holds the cell while P2 carefully places the transit case+nipple on the Sb cell
1. P2 placing the transit case
P1 holds the cracker/nipple together while P2 places bolts and tightens them down. Be mindful that this seal needs to maintain vacuum.
1. P1 holding the cell while P2 places and tightens bolts
Finish up by removing the studs from the mounting fixture and re-wrap it in clean foil.

Sb Cell

Loading Antimony Into Crucible

Important Notes

Loading Procedure

Sb Cell