Planning and Design of Instrument Facilities

[Probeman]

This is all really useful stuff. We're in the process of scoping some new labs, and I'm keen to lay down some of this information to justify my requirements. The project manager has already said the 0.1 degree variation limit is impossible, so I can now challenge him on this - thanks Jon. I've already had to point out several times that putting the electron microscopes next to the induction furnaces isn't going to work, or that putting them next to the high speed load frames was any better.

I do have a question for everyone though: If you had a completely blank canvas what would your ideal room layout be, say for a probe, a couple is SEM's (including FEG), and a dual beam, plus sample prep facilities. I'm already assuming the pumps, gas supplies and UPS's will go in a separate service corridor- with active cooling and sound proofing.

Mike

Hi Mike,
0.1 C is totally doable if you have a good engineer. You are more than welcome to chat with the engineering guy/firm we used. He wrote me last year:

The basic design is a Variable Air Volume (VAV) Terminal unit reheat system using hot water for reheat.   I specified the Siemens "Lab Room Controller" that tracks and coordinates the delivery of supply and exhaust airflow measured in these other Terminal Units to maintain the desired pressure relationship, as well as maintain room temperature control.  There's lots of information on this Siemens system as well as other manufacturers of similar on the web.  There's no specific model number but Siemens Laboratory Control will get them there.

His contact is:

Dave Knighton <DKnighton@bhegroupinc.com>

And his firm is:

http://bhegroupinc.com/

Amazing that they are right here in little Eugene, OR!   My only complaint about the temp control is that my very nice standard intensity drift correction in PFE isn't getting a good workout anymore!   

As for layout, I think one wants to go for a medium volume room for housing all the instruments (which also helps to maintain a constant temperature through sheer thermal mass). We are totally satisfied with our setup as seen in this picture (attached) which has two EPMAs and an E-SEM.  And yes, you absolutely need to have all the pumps/chillers/gas cylinders in an adjoining gallery with separate ventilation and temp control.
john

[Anette von der Handt]

Yes, I agree with John, a decently sized room that allows the air masses to be stable is the way to go.

One thing that I learned from the literature that I listed above is also how noise as well as air movement on the column is really bad for precise positioning and image stability. Low air flow is very important and I have seen a lot of labs are using these air socks to further improve on that. No air outlet directly above the machine.

From the Muller et al. (2006) paper: "Airflow at the column should not exceed 30 ft/min and ideally be less than 15 ft/min. This can be checked with the ‘‘toilet-paper test’’ [6]: take a single-ply strip of toilet paper, cut it into 1 ft long and 1/8 in. wide sections. Decorate the room. If the strips deflect by more than an inch at the bottom, the airflow exceeds 20 ft/min."

Check out this Muller paper in particular. I wish I had found it earlier in the process. I gave it to the architects and it supports  and explains nicely my requirements for the rooms.

Further aspects that went into my lab design.

• Sample prep is in its own room.
• I have a vestibule in front of the lab to further isolate it from the less climate controlled hallway.
• Slight positive air pressure relative to the hallway to keep the dirt outside.
• Clean room ceiling tiles (Rockfon Hygenic Plus) to keep the room clean. They should also provide excellent noise absorption (NRC 0.90).

I attached my floor plan, it is only for a single instrument, although I might have a small SEM for teaching and demos on loan at times. One plan shows the HVAC system and one the currently planned layout (any constructive criticism very welcome). For fun, I also attached a lab floor plan from an old microscopy book that shows how times have changed (the need for dark rooms!).

Anette

[Mike Matthews]

Thanks guys and gals, all very useful info. I'll certainly look up the Muller paper.

[dawncruth]

Hi all,
We've just had our site survey and the preliminary assessment is that most parameters are fine. However, the AC fields are over specs for our new FEG probe. When installing in your facility, how did you solve this problem.

Keep in mind the following:
1. Our current space is not great. So we are installing in our newest building, with the wonky AC fields.
2. We are building a new lab space, which won't be completed for at least 3 years. We will re-install our new probe then.

Are there relatively inexpensive solutions for crazy AC fields?

Thanks,
Dawn

[JonF]

Are there relatively inexpensive solutions for crazy AC fields?

That depends on what you consider to be expensive!

JEOL supplied us with a Spicer AC & DC field cancellation system for our 8530F. It lives in an aluminium profile cage around the probe itself, so it's footprint isn't any bigger. There's a couple of X Y Z field sensors around the column, and the electronics box sat on the probe electronics behind the machine.
It moved with the probe when we shifted labs.

[dawncruth]

Are there relatively inexpensive solutions for crazy AC fields?

That depends on what you consider to be expensive!

JEOL supplied us with a Spicer AC & DC field cancellation system for our 8530F. It lives in an aluminium profile cage around the probe itself, so it's footprint isn't any bigger. There's a couple of X Y Z field sensors around the column, and the electronics box sat on the probe electronics behind the machine.
It moved with the probe when we shifted labs.

Ooh, this is helpful. Thanks for the input, and importantly the brand name and knowledge that JEOL has provided in the past!

[Probeman]

This reminds me a little bit of a funny story from my early days at LBL in Berkeley.

I worked for several years in Building 70A and one of the labs there installed a new Zeiss SEM which they got up and running fairly quickly. Once the Zeiss engineers left they started using the SEM, but every once in a while the instrument would simply not produce an image for hours at a time. And then the imaging would suddenly be OK again. Went on for weeks like this. So they had the engineers come back in and one in a while the engineers would see the issue also, but were not able to figure out the problem.

I should mention that this building was constructed on the side of a very steep hill and had many entrances/exits. So one could enter or leave the building from several different "floors". One day my boss, who at the time who would sometimes explore the building by leaving from different exits, was wandering around and came across a lab he had never seen before, so as he was peeking in at the open door, one of the scientists asked if he could help, and my boss said he was just curious, so the guy invited him in for a tour.  As they went around the room, the scientist explained each of the pieces of equipment and eventually they came to this big doughnut shaped thing in the middle of the room, and then the scientists said: and this is our new super conducting magnet!

At that point my boss realized that the SEM which they were having intermittent problems with, was located in the lab above, about 10 feet directly over the superconducting magnet!  Of course every time they turned that darn magnet on the beam went away!

[dawncruth]

Building woes abound and pandemics suck.

The probe is set to be delivered on 26 May. The room won't be ready until 1 August because of shelter in place orders and other issues. I am trying to do all I can to get the room as close to ready as possible, so essentially everything but the electrical work.

Anyway, we are replacing the acoustic tiles in the lab space because 1) they are old, and 2) the lab was previously a geo-tech experimental space so it was quite dirty.

A caveat: this space is temporary as we are building our fancy new building which will be amazing in all ways 
So we just need a clean and functional solution for the acoustic ceiling tiles, not necessarily the be all and end all solution.

Any suggestions?

[Anette von der Handt]

Sorry to hear, that is bad timing indeed.

I have Rockfon Hygenic Plus ceiling tiles in my lab. They are low particle emission and have excellent sound absorption. The planners suggested them so I don't know what else is out there but I am happy.

[sem-geologist]

damn, I read this thread with jaws dropped and envy. 0.1 C Air conditionig (AC)... I am bumping my head to wall we have nothing like that in our lab. The lab grade AC would be making my life much easier with FEG instrument. We have comercial grare AC and still this is much better than consumer grade, but that is far from 0.1 (day peak to peak around 0.9 C, seasonal drift  up to 3 degrees during weather changing). Problem is that AC pipes are running for more than 50 meters between internal-exterial units, and so AC have poor response function and is highly susceptible to seasonal changes (winter vs summer).

About magnetic fields. We don't have cancelation in our EPMA lab. Our facility is by roads (by intersection) where heavy weight (trucks) vehichles are rare, and fortunately tram and metro lines are far away (those introduce enourmous anomalies in the field). Our facilities SEM lab has cancelations. and now comes an Anecdotal observation. SEM under those cancellation fields often experiense drifts, but our not-cancelled EPMA never. I have my theory about this. First of all EPMA (Cameca SXFiveFE) have built shield around column where all those metal parts are grounded to the same ground reference (column itself is a bit like pseudo Faradays cage). All EPMA electronics work with the same ground reference. So I think that natural daily magnetic cycle is not influencing instrument at all as common ground and earth magnetic field are interconnected. Now Our SEMs with cancelation field have clear daily drifts, because with cancelation field the SEM surounding field is detached from ground reference which is dynamic. SEM facility is closer to the street and so it needs to cancel rare field spikes introduced by passing bus (during day every ~10-20min) or random trucks passing at night (heavy weight trafic is forbiden during day in Warsaw).  So If your planned facility is far from heavy moving metal objects you could do without field cancelation. But if you have heavy trafic nearby - field cancellation is a must.

One more considerations. Gas (P10) shoul be mounted to the internal wall, as outer wall is more susceptible to seasonal temperature (our own experience).

[sem-geologist]

... one more. If it will be Field emission instrument without (like cameca instruments) bulky shield case covering/hiding column and its junctions behind cover (i.e. Zeiss SEM). You need to be sure that there will be no direct air blow from AC. Due to high vacuum requirements junctions use metal gaskets instead of rubber o-rings --- with periodic airblows you can get periodic micro leaks as with cooling metal it gets less tight. (our own experience)

[Probeman]

damn, I read this thread with jaws dropped and envy. 0.1 C Air conditionig (AC)... I am bumping my head to wall we have nothing like that in our lab. The lab grade AC would be making my life much easier with FEG instrument. We have comercial grare AC and still this is much better than consumer grade, but that is far from 0.1 (day peak to peak around 0.9 C, seasonal drift  up to 3 degrees during weather changing). Problem is that AC pipes are running for more than 50 meters between internal-exterial units, and so AC have poor response function and is highly susceptible to seasonal changes (winter vs summer).

I have to admit it wasn't easy getting to this temperature specification. First it had to be accepted by the design committee (it helped that our VP of research was a former microscopist!), and second agreed to by the building design engineers (I had to tell them they couldn't do it, so they tried really hard to prove me wrong!). It also helps that our building is underground.

Finally, I'm pretty sure this sort of temperature control can only be accomplished in a new building design and construction.  Retrofits have too many uncontrolled variables.

[Jacob]

I had a demo of a WDXRF instrument a couple months back and I was talking to the applications engineer about how they deal with temperature stability.  The WDXRF system in question didn't require any extensive temperature controls.  They solved the temperature stability problem by heating the entire instrument enclosure to 32C. Because heating is so much simpler to do, and the enclosure is a small volume, the built in heater is able to keep the instrument at a constant temperature quite easily.  I'd say 32C is also a reasonably safe temperature for virtually all the hardware on most systems.

Could be a fun solution for vendors to look into.