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Leica S430 Scanning Electron Microscope (view source)
Revision as of 21:49, 15 November 2016
, 21:49, 15 November 2016no edit summary
|certification=yes
|certification=yes
|hackable = NO
|hackable = NO
|where = Removed
|model = Leica Stereoscan 430
|model = Leica Stereoscan 430
|serial = 430-02-01
|serial = 430-02-01
|arrived = 3/23/2013
|arrived = 3/23/2013
|contact = Ryan Pierce
|contact = Ryan Pierce
|value = $100,000.00
|value = $100,000.00
}}
}}
'''This machine has moved to [http://www.analyticslounge.org/ Analytics Lounge] per [https://wiki.pumpingstationone.org/Vote_to_Donate_SEM this vote], so it is no longer available at PS:One. This page remains because it may still contain useful information'''
== Configuration ==
== Configuration ==
* Ethernet. Scripts set up to FTP image files for each user to [ftp://semsrv.pumpingstationone.org ftp://semsrv.pumpingstationone.org] which is accessible only inside PS:One's network.
* Ethernet. Scripts set up to FTP image files for each user to [ftp://semsrv.pumpingstationone.org ftp://semsrv.pumpingstationone.org] which is accessible only inside PS:One's network.
== Certification ==
== Authorization ==
This is probably the most complex piece of equipment we own. As such, certification will be broken into different levels which qualify a user to perform only certain specific tasks. Unlike other PS:One equipment where anyone certified can, in turn, certify anyone else, at present the only person who may certify others is Ryan Pierce. We anticipate we will have additional trainers in the future.
This is probably the most complex piece of equipment we own. As such, authorization will be broken into different levels which qualify a user to perform only certain specific tasks. Unlike other PS:One equipment where anyone authorized can, in turn, authorize anyone else, at present the only person who may authorize others is Ryan Pierce. We anticipate we will have additional trainers in the future.
=== Scanning Electron Microscope User ===
=== Scanning Electron Microscope User ===
* Vent the chamber and restart the vacuum pumps. (only if necessary)
* Vent the chamber and restart the vacuum pumps. (only if necessary)
Users possessing this certification may not:
Users possessing this authorization may not:
* Use the Backscatter or EDX detectors.
* Use the Backscatter or EDX detectors.
|-
|-
|Cameron Rudnick
|Cameron Rudnick
|Ryan Pierce
|-
|Mike Warot
|Ryan Pierce
|-
|Dave Schact
|Ryan Pierce
|-
|A. Catherine Noon
|Ryan Pierce
|-
|[[User:ad9581|Arturo Duarte]]
|Ryan Pierce
|-
|Melody Snyder
|Ryan Pierce
|-
|Sache
|Ryan Pierce
|-
|Scott Anamizu
|Ryan Pierce
|Ryan Pierce
|}
|}
=== Backscatter Detector User ===
=== Backscatter Detector User ===
Users possessing this certification may:
Users possessing this authorization may:
* Move the four quadrant backscatter detector in and out of the beam path.
* Move the four quadrant backscatter detector in and out of the beam path.
* Image samples with the 4QBSD.
* Image samples with the 4QBSD.
As the 4QBSD is currently undergoing maintenance, this certification is currently on hold. It will be rolled into the Microscope User certification and made part of that curriculum at a future date.
As the 4QBSD is currently undergoing maintenance, this authorization is currently on hold. It will be rolled into the Microscope User authorization and made part of that curriculum at a future date.
=== EDX Detector User ===
=== EDX Detector User ===
Users possessing this certification may:
Users possessing this authorization may:
* Operate the EDX detector.
* Operate the EDX detector.
* Fill the EDX detector with liquid nitrogen.
* Fill the EDX detector with liquid nitrogen.
PS:One only recently acquired equipment for transporting, storing, and dispensing liquid nitrogen. An EDX authorization class is forthcoming.
=== Sample Preparer ===
=== Sample Preparer ===
Users possessing this certification may:
Users possessing this authorization may:
* Mount samples on stubs.
* Mount samples on stubs.
* Pump down the SEM chamber.
* Pump down the SEM chamber.
This certification is currently on hold pending repair of the sputter coater and acquisition of an argon tank for the sputter coater.
This authorization is currently on hold, but we anticipate to offer it shortly.
=== Microscope Maintainer ===
=== Microscope Maintainer ===
|SEMSRV (virtual Linux FTP server)
|SEMSRV (virtual Linux FTP server)
|1E:0B:6B:E6:2D:9C
|1E:0B:6B:E6:2D:9C
|10.100.0.16
|10.100.0.108
|-
|-
|SEM
|SEM
|-
|-
|EDX
|EDX
|08:00:09:51:95:28
|08:00:09:51:A5:28
|10.100.0.41
|10.100.0.41
|}
|}
* Chamber and gun gaskets should be greased with a suitable high vacuum grease, e.g. Apiezon M.
* Chamber and gun gaskets should be greased with a suitable high vacuum grease, e.g. Apiezon M.
* Rotation speed on the turbomolecular pump can be checked, which correlates to chamber pressure.
* Rotation speed on the turbomolecular pump can be checked, which correlates to chamber pressure.
Cleaning the Penning gauge now results in a significantly more stable vacuum reading, with no wild fluctuations that defy the laws of physics. It had significant accumulated plating on the anode and cathodes, and loose black shiny grit in the gauge, which could cause erroneous readings. However, the gauge doesn't indicate below 1.09e-4 torr. Thoughts:
* Contamination in the Penning gauge often results in less current flow, which registers as a lower vacuum reading than is actually present.
* It is possible that we really have been running at 1e-4 torr all this time without realizing it. This is certainly not ideal, but a beam can pass through the column and image at this level.
* While the chamber air admit solenoid may be a possible culprit, this seems unlikely. Air leaks usually are larger than this. Still, plugging the solenoid is an easy way to check.
* The turbomolecular pump is now a likely suspect. 1e-4 torr is only marginally better than a roughing pump can achieve. Turbopumps should drop the pressure into the e-6 range. It is possible the pump is not running at full speed. This should be investigated via the pump controller.
* Applying light finger pressure to the air admit solenoid causes the chamber pressure to drop from 9.3e-5 torr to as much as 9.0e-5 torr; releasing it causes it to return to the starting value. This is repeatable. It suggests a possible leak related to the air admit solenoid.
After removing the Penning gauge, cleaning the O ring of residual black sand grit, and reassembling, pressures in the 9e-5 torr range can be achieved. Attention turned to the Edwards EXT120E turbomolecular pump controller. This has an analog output from 0-5 V proportional to pump speed on pins 16 and 17. (Polarity appears backwards from what the manual states.) I measured 4.955V, corresponding to the pump running at 99.1% speed. Thoughts:
* It is therefore very unlikely that we have bad bearings causing the pump not to run at full speed.
* Tightening the Penning gauge did produce a change in vacuum of around 5%. However merely rotating the magnets, which are in an external sleeve, changes the vacuum too. It looks unlikely to be a leak in the gauge. Rather, the gauge seems to be very dependent on physical orientation, even though, if left alone, the results are now very stable.
* Pushing the pump around when running did not produce a change in vacuum.
* Pushing around the solenoid valve did produce a change in vacuum.
* One of the bolts holding the solenoid on was loose. Tightening it didn't seem to be the fix.
* It is likely the solenoid valve leaking. Replacing the solenoid valve with a rubber stopper is the next step to troubleshoot the problem.
Solenoid valve was removed and replaced with a rubber stopper. This clearly fixed the problem, as low 1.0e-5 torr vacuum could be achieved. Attempts to repair the old solenoid were unsuccessful. Solenoid was replaced with a new old stock Edwards C41723000 24V NO solenoid. This required hacking together an NW10 adapter to connect to the air hose leading to the desiccant dryer / filter, and obtaining an NW10 centering ring and clamp.
This adequately solves our vacuum issues. 1e-5 torr is acceptable. In the future, we may attempt treating rubber O rings with vacuum grease in an attempt to improve the final vacuum into the e-6 torr range.
=== Image Processor board loses communications ===
=== Image Processor board loses communications ===
A dual cable plugs into a single port, Opto 1, for the HRRU pixel data. The fiber plug connector on the cable end has snapped. This is not critical as we are not using the HRRU.
A dual cable plugs into a single port, Opto 1, for the HRRU pixel data. The fiber plug connector on the cable end has snapped. This is not critical as we are not using the HRRU.
Repair is possible. The connector in question is a "hp 9534 R-2521" with a T-2521 next to it. These appear commonly available, but soldering to the image processor board should be considered a last resort.
Repair is possible. The connector in question is a "hp 9534 R-2521" with a T-1521 next to it. These appear commonly available, but soldering to the image processor board should be considered a last resort.
We have removed the external fiber cables tangled with the others. This has largely reduced the incidents of vacuum crashes due to communications failures, but not entirely eliminated them. One failure has happened since then.
== Maintenance Log ==
== Maintenance Log ==
! Maintainer
! Maintainer
! Description
! Description
|-
|10/30/2014
|Ryan Pierce
|Shut down SEM for repair of the rotary vane pump. Vented chamber. Removed all samples. Disconnected rotary vane pump. Disconnected electrical power. The rotary vane pump is exhibiting signs of overheating, scorching the oil, making very loud, regular clacking noises in time with the pump stroke, emitting a scorched oil odor, possibly allowing oil vapors to escape back up the line when the pump is turned off, and may have a small oil leak.
|-
|9/20/2014
|Ryan Pierce
|Finished vacuum system repair. Had previously replaced the air admit solenoid with an Edwards C41723000 24V NO solenoid. This produced a vacuum around 1.03e-5 torr. Added custom made adapter from NW10 flange to the fitting on the old solenoid that attached to the air dryer. This adapter was made by cutting apart the old solenoid, TIG welding a pipe compression fitting, which mechanically held the hose fitting. This was not airtight, so was sealed with epoxy. Chamber now vents properly and holds a vacuum. Re-assembled desk. Dried silica gel in an electric oven at slightly under 200F for several hours in a baking dish, stirring periodically, until bright blue color returned, and re-assembled air dryer assembly. Noted oil in rotary vacuum pump was running low, topped it off.
|-
|6/15/2014
|Ryan Pierce
|Replaced filament. Prior filament had 52 hours. Suspect user error setting current too high, however the filament was operating for most of its life at a very poor vacuum. Also changed out Weinhelt aperture with used spare. Old one needs to be cleaned and polished, not exactly sure how. Need to contact Susan (former operator.) At 10 kV, 1000x, 90 pA I Probe, first peak at 2.61A, second peak at 2.86A. Also corrected connection of mist and odor filter to rotary vacuum pump, which was not properly seated.
|-
|5/?/2014
|Ryan Pierce
|Removed chamber air admit solenoid. Replaced with rubber stopper. Vacuum ultimately gets to 9.6e-6 torr.
|-
|5/18/2014
|Ryan Pierce
|Noted turbomolecular pump analog speed voltage at 4.955 V, corresponding to the pump running at 99.1% speed.
|-
|5/1/2014
|Ryan Pierce
|Disassembled Penning gauge, straightened anode wire better, noted some of the particulates on the O ring, cleaned it better with a kimwipe, and reassembled. System pressure is now 9.3e-5 torr, which is sufficient to run the beam.
|-
|4/29/2014
|Ryan Pierce
|Disassembled Penning gauge, straightened anode wire better, cleaned O ring with kimwipe, and reassembled. System pressure is lower, measured at 1.09e-4 torr on 5/1/2014.
|-
|4/26-27/2014
|Ryan Pierce and Elizabeth Koprucki
|Disassembled Penning gauge. It was filthy with plated material and loose shiny black sand-like material. Sanded anode and cathode cups to remove the bulk of plated material. Removed ion trap and sanded interior metal surfaces. (The plastic surfaces are filthy, but I don't know how to clean this.) Cleaned all metal parts in 3 progressive changes of acetone in an ultrasonic bath. Anode wire was bent in re-insertion. Following re-assembly, pressure was 1.5e-4 torr.
|-
|-
|4/7/2014
|4/7/2014