[Sem] All in on the mini-SEM?

[Jeff Miller]

I think we should give the mini-sem project a second chance. 

I've been thinking about what the SEM experience at NB drove home.
We should think small and practical. 

Rather than a clean room, let's think glovebox. Small glovebox, easy enough to fab.

The manual vacuum controls have to go. It should all be electric valves, interlocked and goof proof.
The coater should be integrated, and interlocked with the SEM to use the same pump(s). 
Perhaps a small, low temp vacuum oven for drying bugs and plant samples, too.

The console has to more or less go. We have to commit to the digital platform I developed, or develop a new one. 
Ideally, the diff pump and forepump should be replaced.with a turbo and a diaphragm pump. With that we get instant on, no exhaust fumes. and no periodic cleaning of the column parts.
Alcatel makes a high speed molecular drag pump. I may be wrong, but I don't think it has stator blades. So I think you can up-to-air it at full speed with no damage, and it may be able to choke down a grain of sand or two without exploding. It will be mounted upside down of course. 

The vacuum isn't as deep as theoretical for a turbo or diff pump, but is more than sufficient for a SEM and coater. 

I have a bunch of these pumps.  So many in fact that I'm thinking of coughing up the $1,000 for the factory toolkit (probably a bearing puller and two precision bore steel plates, if that) to rebuild them. I think the bearings alone go for $300, but it shouldn't be hard to find a pump with bad bearingsfor ~$250.  The pumps have a very high foreline pressure tolerance, 30 torr I think: I've seen them backed with run-of-the-mill two stage diaphragm pumps from Gast.  Meanwhile, high performance four stage diaphragm pumps seem to be fetching less than half of what I was getting for 
them 5 years ago, $150 might buy a working pump and $200 more might effectively rebuild it. 

As it turns out, I've already done some of the heavy lifting. It's probably been close to ten years now since I first wanted to make the mini-sem portable, to bring to classrooms. To that end I had custom pieces milled that attach to the top and bottom vacuum ports, and convert them to the KF standard. Short lengths of stainless bellow also show up cheap enough these days.
Perhaps as much as anything, it would highlight vacuum technology as well as the SEM itself. 

I might have almost everything we need on hand. I can see lending the core components for proof of 
concept , or until they can be found serendipitously on ebay.. 

For all the little pieces and parts, $200-$300 might be a good guess and represent a good working minimum budget for retrofitting the valves and 
piping.  If we have to do it from scratch, the glovebox could be another $150 or so but further down the line. 

I say pitch it as far more user friendly and less invasive, and see if we can get funds allocated. 
Anyone care any more? How are you guys coming along with your SEMS, coaters, and turbos? 

-Jeff

 








      From: Chris Murphy <chrisnoisebridge at gmail.com>
 To: John McMaster <johndmcmaster at gmail.com> 
Cc: "sem at lists.noisebridge.net" <sem at lists.noisebridge.net> 
 Sent: Tuesday, September 2, 2014 12:13 AM
 Subject: Re: [Sem] Picked up a sputter coater
   
Well that's a breakthrough. Maybe Alan has something to coat. 

Sent from my iPhone

> On Sep 1, 2014, at 22:41, John McMaster <johndmcmaster at gmail.com> wrote:
> 
> ...3.5 hours of driving each way later.  Hit me up if you need to coat something.  I have a gold target for it
> _______________________________________________
> SEM mailing list
> SEM at lists.noisebridge.net
> https://www.noisebridge.net/mailman/listinfo/sem


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