[Sem] All in on the mini-SEM?

Tue Dec 16 03:11:30 UTC 2014

I have a very large hoard of spare ISI supplies including filaments. 
Doesn't matter though if I can't pull a good vacuum first

On 12/15/2014 06:54 PM, Jeff Miller wrote:
> BTW I saw your blog, sounds like you need a new filament. They burn
> out every 25 hours or so. I hope you got the filament holder/whenelt.
> They are consumables but $$ and frequently pirated. I think most for
> ISI are the same, I have a few in fair condition I might sell one.
>
> -Jeff
>
> ------------------------------------------------------------------------
> *From:* John McMaster <johndmcmaster at gmail.com>
> *To:* Jeff Miller <mysterylectricity at yahoo.com>; Chris Murphy
> <chrisnoisebridge at gmail.com>
> *Cc:* "sem at lists.noisebridge.net" <sem at lists.noisebridge.net>
> *Sent:* Friday, December 12, 2014 7:09 PM
> *Subject:* Re: All in on the mini-SEM?
>
> Heyo,
> I haven't followed the noisebridge unit, but some updates on my side
> if anyone is curious.
>
> I traced the vacuum leak to the column in my Super IIIA.  I'm having
> trouble safely taking apart the column to troubleshoot further.
>
> Over the previous weekend I picked up a small ISI SEM similar to the
> noisebridge unit ($500 + drive to LA and back).  Some details on it
> here: http://uvicrec.blogspot.com/2014/12/theyre-multiplying.html
>
> The guy also threw in a carbon coater.
>
> Anyway, it has a broken PMT and needs a small vacuum adapter that
> should have come in the mail today.  PMT has unknown ETA but I could
> steal a spare off of the Super IIIA if I wanted to test sooner.
>
> I also have a *huge* (over 100 lbs) pile of ISI documents (schematics,
> mechanical drawings, service notes, etc) I've been scanning in that
> one of their retired lead techs gave me.  Maybe this weekend I'll
> finish the digitaization process and begin uploading/organizing them.
>
> I have a small Pfeiffer/Balzers turbo pump system I assembled off of
> eBay for under $500.  It was chosen specifically because parts for
> this particular system are readily available to piece together.  Of
> course, it would be hit or miss if the bearings are sub-optimal but I
> imagine often times they will be good enough for hobbyist use.  I'd
> suggest others looking into the same route before dropping 1k on a
> restore kit.  I haven't decided if I'm going to attach it to the SEM
> once it works better.
>
> I get class 10k using a high power Honeywell HEPA filter in my
> bedroom.  Very cheap and easy to setup.
>
> John
>
> On 12/12/2014 05:56 PM, Jeff Miller wrote:
>
>
>> 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 bearings
>> for ~$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>
>> <mailto:chrisnoisebridge at gmail.com>
>> *To:* John McMaster <johndmcmaster at gmail.com>
>> <mailto:johndmcmaster at gmail.com>
>> *Cc:* "sem at lists.noisebridge.net" <mailto:sem at lists.noisebridge.net>
>> <sem at lists.noisebridge.net> <mailto: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
>> <mailto: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
>> > _______________________________________________
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>> > SEM at lists.noisebridge.net <mailto:SEM at lists.noisebridge.net>
>> > https://www.noisebridge.net/mailman/listinfo/sem
>>
>>
>>
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>
>
>

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