February 2013
1 post
BRB playing with rockets →
Sad and excited to say that the HSL SEM project is on the back burner (but not on hold! Big difference!) while I send some things to the ISS.
BRB. (Go Antares!)
December 2012
3 posts
TIG Welding for Fun and Profit
So I recently championed the acquisition of a nice TIG welder at the Heatsync Labs hackerspace (special thanks to Karl at K-Zell Metals for getting us such a good deal). I want us to always be able to make anything, even space ships, so I want us to have the tools we need, be it laser cutters or TIG welders. However, my real reason for wanting a good welder was to weld vacuum chambers, fittings,...
September 2012
5 posts
Electron Gun Mark II
I kicked around a few ideas about how to build a free standing “developmental” version of the gun, with an improved rigid support structure. Also shows is an all-metal version which should prove to be better as a final version, though it sadly hides the entire discharge tube from sight and therefore is not a good candidate for a “development” item. Call it future idea...
8 tags
A Better Cold Cathode Electron Gun
Time to make things better. The first prototype cold cathode electron gun used a piece of aluminum foil as a beam aperture. Talk about a not at all precise piece of optics. The new Mark I gun uses a lathe turned rubber stopper to support a piece of lathe turned tungsten and a small peiece of #32 AWG wire to bias a lathe turned aluminum anode with a 0.46mm aperture.
Interestingly enough the...
An Awful Horrible Deliciously Hacked Up Electron...
Its not pretty. (Is… is she using a… harbor freight clamp to hold the lens at the focal point? yikes…) I’m sorry, because, it is in fact indeed awful and horrible and hideous. Its arguably uglier than my current divorce… (hilarious! … *crickets* …*clears throat*) But you know what it is?
Its a gap-solenoid electron lens! Its a baby step, and I might...
June 2012
6 posts
Happy Accidents
What happens when water gets into the beamline during a leak check? Amazing accidental plasma art!!
Cold Cathode Electron Gun Part 1
Please bare with me, this narration is coming from the past. I try to always take pics and document everything but life happens and the blarg doesn’t get updated and then I have to do this :)
Using what I saw on Mr Styner’s amazing and truly humbling website, I constructed a simple experimental electron gun using a copper wire in a capillary tube, a rubber stopper, and a turned...
Inspiration From an Old Hacker Hero
More about the cold cathode low pressure electron gun I spoke of in the last post.
The inspiration to even try a low pressure electron gun came randomly, through the usual exploratory google search. However, I wasn’t searching SEMs, electron guns, or even vacuum physics… [[MORE]] I was helping Erica build a theremin, and randomly stumbled across Mr Nyles Styner and his EWI...
6 tags
3 tags
December 2011
3 posts
Scanning Electron Microscope Project Update →
As presented to Heatsync Labs, the home of the HSL SEM!
4 tags
10 tags
September 2011
5 posts
6 tags
11 tags
5 tags
August 2011
1 post
July 2011
1 post
Lid welds have been verified!
The SEM welds have been leak tested and verified to be good to at least 10^-3 Torr! Click below to read on and see some vacuum porn!
The original idea was to use the O-ring present within the face of the lid to “suck” down onto a polished stainless steel plate with the vacuum hose attached to one of the KF-25 flanges with a gauge on the other KF-25 flange and a cap on the KF-40...
June 2011
1 post
May 2011
1 post
4 tags
April 2011
12 posts
Filament transformer design
SEM filaments are biased at a large negative potential with the anode and specimen placed at ground potential. 1-20kV is a reasonable range for the bias voltage. However, the tungsten hairpin filament requires a large current, several amps. So how do you bias a current source at such a high potential?
Step 1 Find a huge transformer
A good rule of thumb is that the power of a transformer...
4 tags
How to measure a vacuum - Thermocouple Meters
Knowing how much air is in a vacuum chamber is really important. You can keep an eye on possible leaks, outgassing, but you also need to know if you are going to break something. Tungsten hairpin electron emitters will burn up at pressures greater than 10^-2 torr, a diffusion pump cannot be turned on until 10^-3 torr or fire will happen, and a sputtered ion pump works best at 10^-6 torr or...
Vacuum Chamber Work - HOLES
The welder requires precise holes in order to get the best quality weld and to avoid potential problems. Corey was nice enough to let us use his skills and his shop to do the milling.
The KF25 flanges were a piece of cake, standard size bore.
The KF40 and KF50, however, were slightly off and a boring tool was required.
Vacuum Chamber Work - Flanges!
It was decided that we needed a major overhaul to the chamber anyway, so instead of fix the existing valves we decided to drill out all of the holes and TIG weld real vacuum flanges onto it. We found a welder, Claude, at Mesa Community College who was willing to help us out and in fact volunteer his time as long as we paid for consumables (shield gas). WOW! Thank you SO MUCH Claude!!
But before...
Vacuum Chamber Work
Step 1 is to create a vacuum. Obviously we need a vacuum chamber to do this.
Heatsync raised $400 in order to purchase this surplus aluminum vacuum chamber and I fronted the extra $400 required to cover the chamber and the dual vain rotary pump. THANK YOU to everyone who pitched in to help!!
A course vacuum was achieved within days, however it was discovered that there was a leak…....
SEM Technical Goals and Direction
The HSL SEM is a complex project but it can be broken down into bite-sized chunks. The major goals are listed in the order that they will be created.
Vacuum - Vacuum chamber, Pumps, Flanges
Electrical feedthroughs - Epoxy, O-rings, brazed alumina
Electron emitters / gun - Tungsten hairpin wire, HV power supply, Wehnelt
Electron lenses - Machined pole pieces, coil winder, drive circuitry
...
HSL SEM Goals Defined
Image quality is more important than insane magnification
An all digital interface with an emphasis on software processing techniques and modern microcontroller interfaces.
Portability which will allow for its use within varied and diverse educational opportunities.
Low cost “hacked up” methods of fabrication to discover new and more efficient ways of solving some of the most...
Just shut up and hack
Has anyone at Heatsync Labs ever built an SEM before? No. Have any of us worked in medium or high vacuum technology? Not really. Is that going to stop us? hah! Just shut up and hack.
On Feb 17th I gave a talk at the HSL biweekly meeting along with Brandon Guida. Brandon works in the ASU Microscopy lab and they have SEMS, TEMS, and all sorts of other EMs there among other things.
In our talk we...
Welcome to the Heatsync Labs SEM Buildblog
Welcome to the buildblog for the Heatsync Labs SEM. Let’s backtrack a little bit and bring everyone up to speed.
SEM is short for Scanning Electron Microscope. And a Scanning Electron Microscope is capable of some truly amazing imaging. Just google image it.
SEMs start at around US$70,000 and can rocket into the millions of dollars. From tiny tabletop units to massive beasts capable of...
