NetNotes


normal. FEG sources are generally good for 2–3 years of continuous service or up to 10,000 hours. I do know that with time the FEG source can get a funny shape to it. Pete Eschbach peter.eschbach@oregonstate.edu


Two ideas: 1. Te filament tip might be damaged. Check the


resolution at 30keV; if it is OK, then the tip is most probably okay, and you should fix the low kV alignment. 2. Depending on your instrument, the best resolution might be obtained at a higher probe current than the minimum setting. Tomáš Hrnčíř tomas.hrncir@tescan.com


In addition to the gold standard used to measure the resolution, I


used real samples such as metallic PVD nanolayers. Tree factors need to be improved to get a 1,000,000X image: 1. Te magnetic interference of the Faraday cage coil system should be minimized; 2. Te anti-vibration shoe system should be minimized to remove any floor chattering effect; 3. Te plasma cleaning system should be used to eliminate carbohydrate contamination. Antonio Carlos Joaquim acjoaquim@gmail.com


Along with all the excellent input and advice already posted,


I’d also recommend cleaning the Au-on-C standard too. Te surface will inevitably become contaminated over time, adding to surface contamination and resolution problems during high-resolution imaging. Plasma or ozone cleaning both work well, plus try storing the standard in a clean cabinet, even under vacuum. Chris Jones c.jones@nhm.ac.uk


Use of a TEM Wobbler for Perfect Focus Microscopy Listserver I’d like to draw on the collective wisdom of the microscopy


community one more time. I have a Philips CM12 TEM and I have a disagreement about the wobbler function. The premise is, if the optics and column are perfectly aligned, even if the sample is out of focus, the wobbler will not split the image into two and allow you to focus. In the twenty years I’ve hung around TEMs, I’ve never seen a scope that is so perfectly aligned, so in tune with the universe, so one with itself, that the wobbler doesn’t wobble a defocused image. Frank Karl frank_karl@ardl.com


I’ve been involved with EM since 1974 and I have never heard


that. Te wobbler is a focus aid. I think this is one of those EM myths. Tom Bargar tbargar@unmc.edu


Te manual for the CM12 and CM10 we used to have stated the


wobbler was for focusing at 25,000X and below. Only. It was useless above 25,000X. But it didn’t matter if the column was perfectly aligned, it would still wobble the image if it were out of focus. Tere was a separate wobble function for alignments. (If I remember right - we got rid of both the 12 and 10 years ago, and with all the microscopy chemicals, concussions, and admin wobblers, my brain may be too wobbled to remember.) Phil Oshel oshel1pe@cmich.edu


Tis may be a hardware problem like misalignment of coil


voltages. Does this problem exist at all magnification steps? I suppose you use a digital camera on the TEM. Why not use the Fourier window (which most camera soſtware has) to do all your corrections more easily? Stefan Diller diller@stefan-diller.com


It would be best to define what you are “wobbling.” All of the following


are possible and all have effects on alignment and the image: HT, gun lenses, monochromators, condenser lenses, objective lenses, projector lenses (not done oſten), beam deflector/tilt coils, image deflector/tilt coils,


62 I have tried that, and the tip comes loose again. I think I will try


crazy glue or epoxy as suggested by Bill Rice. What might be a better design would be to reverse the threads so loosening the top would tighten the tip and tightening the top would loosen it. Tat way it could not get tightened. Robert Grassucci rg2502@cumc.columbia.edu


Developing better tools for handling grid boxes is an area that we


have been looking at recently. As mentioned, many labs are using the “off-label” mechanical/draſting pencil approach. Tese pencils are far from optimal for gripping or for use in LN2


. We would welcome input


from the community on what they might like to see in an optimized gripper tool, or other tools, in the sample prep workflow. Benjamin Apker benjamin.apker@mitegen.com


We had a go at modifying the lids with two small blind holes to fit


a tool with matching pins. It worked very nicely, but eventually we gave up due to the hassle and the tendency of the modified lids to get lost. If someone would manufacture them in a distinctive color, for example, it


www.microscopy-today.com • 2021 November I started a conversation about perfect alignment and the wobbler


for focusing the image. Tat’s been resolved and I thought I’d share the result. I want to thank everyone who contributed to that conversation. In the dark while using the wobbler, someone reached over and while using the multifunction knobs accidently changed the angular displacement to zero. It could have been me; it could have been the new guy; it could have been a service technician. It’s a small group of suspects. Frank Karl frank_karl@ardl.com


Problem Getting Top Off Pin-Type Autogrid Grid Boxes 3D EM Listserver We have been having a problem where users tighten the tops of


autogrid grid boxes and the tool’s metal tip unscrews before the top does. Has anyone found a way to better secure the metal tip of the grid box top tool so it won’t spin, or to ensure the grid box top will loosen before the tip of the tool? Tank you. Robert Grassucci rg2502@cumc.columbia.edu


We use a Pella autogrid box tool for overtightened boxes. Tese


tend to frost up quickly, but since there is no screw, it does not come apart. MiTeGen also makes something similar. Richard Walsh richard_walsh@hms.harvard.edu


Applying a bit more downward force than you’d first feel


comfortable with seems to tighten up the threads in the tool so they don’t slip. I’ve never broken the pin or anything else, but it’s not inconceivable. Just push straight down. You can also swap out the official tool for a mechanical pencil (Staedler Mars technico 788), with which it’s hard to overtighten in the first place. Michael Elbaum michael.elbaum@weizmann.ac.il


all stigmator coils. I’ve been known to wobble all of them to align my instrument. Nestor Zaluzec anl.nestor.zaluzec@gmail.com


I’d be interested to know which (OL or HT wobblers) are best to


get closer to coma-free alignment on JEOL. Another trick for the image wobbler is astigmatism correction (at least on JEOL instruments): 1. focus with WBL-X and adjust O-ST for minimum movement. 2. set the OL to halfway between minimum movement of WBL-X and WBL-Y. 3. correct O-ST for no movement. 4. check Ton rings for confirmation or touch-up. Mike Marko mike.marko.em@gmail.com


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