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--- sputter:pellet [2009/04/15 15:52]
132.235.40.97 created
+++ sputter:pellet [2020/07/27 14:08]
jacobs
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 ====== Cesium Sputter Source Target Change ======
-===== (Revised 4/15/2009) =====
+===== (Revised 7/22/2020) =====
    - Obtain proper target.  Wear clean gloves when handling target and target holder. Determine if target is new or used. Used will have a blackened and scared tip.
+   - Also, determine the proper Buncher Tube setting if you are changing beam species.  This will be your only chance to set it.
    - Turn off DEL HIGH VOLTAGE POWER SUPPLY  (Main Extractor Power)
-   - Record present value and decrease Cesium Reservoir Current to 50%, (~0.25 amp).
+   - Record present value and decrease Cesium Reservoir Current by 50%, usually to about 0.125 amp.
-   - Decrease Ionizer Current to 50% (~ 11 amp).
+   - Decrease Ionizer Current by 50%, to ~11 amp.
-   - Decrease Target Voltage and Extractor Voltage to zero.
+   - Decrease Target Voltage to zero.
+   - Decrease Extractor Voltage to zero.
    - At gate in vault, open gate - the orange lights on the Glassman supplies should go off.  If not, stop and get help.
-   - Hang large ground hook at red arrow on power platform.
+   - Hang large ground hook at red arrow on power platform.  Go around to the other gate and ground the Alpha source.
-   - At the source, hang small ground hook on the target plane of source head.
    - Close gate valve between source and inflection magnet. Controller on source base below gate valve.
-   - Check to be sure the source box Ion gage is on and controller display can be seen from the source head area.
+   - Check that the source box Ion gauge is on and controller display can be seen from the source head area.  You will need to see the pressure in the source box during later steps.  You may have to rotate the controller to see it from the source.
-   - Back off BRASS target positioner and set it aside. If source pressure increases to 2x10E-6, you are leaking too much, tighten silver O-ring collar.
+   - In the steps 13 through 16, if source pressure increases to 2x10E-6, you are leaking too much and should tighten the silver O-ring collar.
-   - Remove the red banana plug (white wire) from the end of the target holder and slowly pull back target holder until it clears the hand gate valve on the source, the target can be seen thru the clear plastic ring.   Close hand gate valve by pushing down on the black knob firmly.  You should hear or feel a click at the bottom of the motion.
+   - Back off BRASS target positioner and set it aside.
-   - Source pressure may rise to mid 10E-6 pressure during this step, this is OK.  Open the small green roughing valve at the target air lock to vent the target area.
+   - Remove the red banana plug (white wire) from the end of the target holder.
-   - Loosen the silver O-ring collar and slowly remove target holder. (wear gloves) Remove the used target.  Wrap in small Kimwipe and store in appropriate container.
+   - Slowly pull back target holder until it clears the hand gate valve on the source, the target can be seen thru the clear plastic ring.  Source pressure may rise to mid 10E-6 pressure during this step, this is OK.
+   - Close hand gate valve by pushing down on the black knob firmly.  You should hear or feel a click at the bottom of the motion.
+   - Open the small green roughing valve (on plastic hose) at the target air lock to vent the target area.
+   - (Wear gloves) Completely unscrew the silver O-ring collar and slowly remove target holder. O-ring should come out with target holder.
+   - (Wear gloves) Remove the used target.  Wrap the used pellet in a small Kimwipe and store in appropriate container.
    - (wear gloves) Install new target; thread on finger tight (Al foil is no longer used).
-   - Re-insert target holder and tighten the silver O-ring collar snugly ( by hand only).
+   - Re-insert target holder and tighten the silver O-ring collar snugly (by hand only).
-   - Close the small valve labeled “VENT” on the roughing line on the left side of the source.  Open the other small valve labeled “VAC’M” in the same area.  Watch the TC gauge on top the source, rough on the target air lock until the vacuum falls back to <30 microns (a couple minutes).  Source vacuum will fall back to 10E-7 once roughing starts.
+   - Close the small valve labeled “VENT” on the roughing line on the left side of the source.
-   -  Close the small green valve at the target air lock and watch the ION GAGE DISPLAY FOR NEXT STEP.
+   - Open the other small valve labeled “VAC’M” in the same area.
-   - SLOWLY open hand gate value.   Vacuum should return to <10E-7 quickly.
+   - Watching the TC gauge on top of the source, rough on the target air lock until the vacuum falls back to <30 microns (a couple minutes).  Source vacuum should fall back to 10E-7 once roughing starts.
-   - Hold the brass positioner in place and allow the assembly to slide forward. Begin threading the brass positioner when it contacts the rod and stop when it reaches the jam nuts.   It does not have to be tight.
+   - Close the small green valve at the target air lock
+   - Watch the ION GAGE DISPLAY FOR NEXT STEP.
+   - SLOWLY open hand gate value.   Vacuum will rise and then should quickly return to <10E-7 range.
+   - Hold the brass positioner in place on its bracket and allow the assembly to slide forward. Begin threading the brass positioner when it contacts the rod and stop when it reaches the jam nuts.   It does not have to be tight.
    - Reattach red banana plug (white wire) on target holder.
    - Pressure may rise slightly as the pellet heats up.
-   -  Re-tighten the silver O-ring collar by hand.
+   - Re-tighten the silver O-ring collar by hand.
-   - Close the small valve labeled “VAC’M” on the left side of the source.  Open the small valve labeled “VENT”  to vent the roughing line.
+   - Close the small valve labeled “VAC’M” on the left side of the source.
-   - Remove the small ground hook from the source head.
+   - Open the small valve labeled “VENT”  to vent the roughing line.
    - Open gate valve between source and inflection magnet.
-   - Remove large ground hook from power platform and close gate.  The orange lights on Glasman power supplies should light up, if not, try pushing the boost button on the wall.   If this still does not make the lights come on, wait a few minutes and try again (leave gate open while waiting to let the actuator cool).
+   - Unground the Alpha source and close the gate on that side of the room.
-   - Use long Plexiglas rod to push the two High Voltage ON buttons located on the top two Glasman Power Supplies.
+   - Remove large ground hook from power platform, hang on the gate, and close the gate.  The orange lights on Glassman power supplies should light up, if not, try pushing the boost button on the wall.   If this still does not make the lights come on, wait a few minutes and try again (leave gate open while waiting to let the actuator cool).
-   - In control room, turn on Del Main Extractor supply to the previous value and return ionizer to 21 A.
+   - Press the doorbell button on top the Pelletron AC Power Center. The Extractor and Target Glassman supplies should indicate Voltage Control with red lights.
+   - In control room, turn on Del Main Extractor supply to the previous value.
+   - Return ionizer to 21 A.
    - Slowly raise the extractor voltage to 12.5 KV.  If you see twitching in the voltage or current meters, stop at that point and wait a few minutes for stability before going higher, until extractor is at 12.5 KV. The twitching will most likely happen if the target pellet was previously used.
    - Slowly raise the target voltage to 6.5 KV.  If you see twitching in the voltage or current meters, stop at that point and wait a few minutes for stability before going higher, until target is at 6.5 KV.  The twitching will most likely happen if the target pellet was previously used.
    - Return the Cesium reservoir to the previous value.
-====  Two hours should produce beam with a previously used pellet.   New pellets may take longer. ====
+====  Two hours should produce beam with a previously used pellet.   New pellets may take 8 hours or longer. ====

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