Applied Furtonic Research

@beamshift @macona The JEOL microscope did have vacuum gauges, but the vacuum meter is just a microammeter calibrated in microamps. I’m not really sure what the actual vacuum pressure is.

@IAtomictek @macona what column pressure gauge reading are you getting to? you might need to clean the gauge itself

High voltage failure occurs, possibly due to electron gun arcing or dielectric breakdown from the high voltage cable.

@macona Yes, this TEM has a diffusion pump using Santovac 5 fluid, and I have a silicone heating tape that I might be able to use to bakeout the column, I’ll try that.

Molecular sieves are fine on the foreline to the pump but im not sure they are going to do much good. I assume this has a diffusion pump? You’re just going to have to leave your pump running. If you can rig up a way to heat up the column and chamber that will help a lot. Wrap in heavy aluminum foil with some lamps under it.

@macona That is reasonable, I’ll be putting some molecular sieves into the chamber and letting it sit for some days.

@IAtomictek Oh man. You’re going to have to pump for a long time to get that down. That thing is full of water. I’m talking days.

@macona Perhaps several years. When I received it, the gun section had been removed, and the top of the column was totally open, with a lot of dust inside, I have to clean it with no choice, There were even nut shells left by squirrels inside the electrical cabinet, horrible condition.

You loaded it with water doing that. It’s going to take forever to pump down. Even though your gauge is showing good vacuum at the chamber thrrr is poor conductance to the column cap and it going to take forever to pump down. How long has the column and chamber been sitting at atmosphere?

@macona Ethanol

@IAtomictek What kind of solvent?

@beamshift Suspecting the problem might be with the cables or the gun, I unplugged the high-voltage connector from the HV tank. When starting up, it seems fine and never tripped the protection. At 100 kV, the beam current is about 100 µA, probably caused by the flow of oil inside the tank.

@beamshift However, sometimes it could stay on stably for a while under 60kV, with an even higher beam current (about 80 µA). When I raised the high voltage directly to 80 kV, it could not stabilize, and every time the beam current went off-scale and tripped the protection.

@macona I cleaned the electron gun chamber with solvent, and the helium leak detector did not detect any serious leak.

@IAtomictek Or your vacuum sucks from leaks or contamination.

Completely refurbished but still not very satisfying. Knowing I could down the rabbit hole but still I’ll design a secondary electron detector & scanning module for this scope, possibly hard decision.

Diffusion pump is running

Power up

Making poor man’s 3-axis hall probe! It’s a replacement for lakeshore MMZ series but this one can handle up to 50kG field.

@CALVINGINEERING These old balzers pumps are nasty cause they’re prone to failure when you got one of these nowadays. Considering its lifespan, cleaning and oil reservoir replacement is advised.

I’m not making a table out of this one I promise.

All rubber pipes have been replaced, especially the evacuation port of the specimen airlock.

TEM airlock motion

Update: Fixed the micrometer that used for sample stage displacement. Vacuum system seems still in tight, when it arrives the camera chamber is still under vacuum. Electronic components still require dust removal

TEM repair time

@nihon_niosumai Oh greatly helpful, thanks! Finally I could export the waveform data from my DDA-260 oscilloscope!

@IAtomictek I'm using WaveStudio. It works even with legacy Lecroy oscilloscopes that are not on the supported device list, as long as they are connected via GPIB or 10M Ethernet. teledynelecroy.com/support/softwa…

ハイクラスレーザー楽しい