Probe Software Users Forum

General EPMA => EPMA Laboratory Planning and Design => Topic started by: John Donovan on September 30, 2014, 01:25:10 pm

Title: Planning and Design of Instrument Facilities
Post by: John Donovan on September 30, 2014, 01:25:10 pm
This board is for discussion of what particular building and room design considerations are helpful or necessary for optimum instrument performance, including floor vibration, EMI, temperature control and dust mitigation.

Please feel free to discuss vendor laboratory environmental specifications and performance and/or your own laboratory room issues (I'm sure we all have a number of stories to tell!).
Title: Re: Planning and Design of Instrument Facilities
Post by: Anette von der Handt on October 10, 2014, 03:10:47 pm
Hi,
Considering that I instigated this topic I finally should post something here.

I am in the lucky position that my department will move into a different building in about 2.5 years (so they say). As lovely as the current building is, it is the second oldest on campus and not really ideal to hold laboratories. The new building will be another old one on campus but the interior will be entirely gutted and re-built. We are currently in the second stage after having had one initial meeting to roughly discuss the lay-out and recently also had to submit some initial room specs.

I hope to get some more input and ideas on this board from people who either went through this process or have to live with a bad room design.

We have currently a JEOL-JXA-8900 but are starting proposal writing for a new probe that may or may not be a field emission microprobe so I would like to have a room that allows for the optimum instrument performance of a new probe.

I will have five rooms connected with each other: (1) Microprobe room (2) Pump/utilities room (3) sample prep room (4) computational room (5) my office. I requested the room specs from JEOL and Cameca for their respective latest FE-EPMA models (8530F, SXFiveFE) and also talked to a few people (John Donovan in particular and Mike J). John specifically also mentioned that the vendor specs are more minimum specs but not necessarily guarantee optimum performance (what I obviously want).

This is what I got so far, cobbled together from the sources mentioned above. I am not sure how important all of them are. Any comments are very welcome.

Thanks!

General:
Lab placement in the building: Basement, away from the elevator, away from the loading dock
No power lines over the machine
No water lines / sprinkler systems directly over the machine
Isolated and insulated re-bars in foundation to avoid ground loops


Microscope room conditions

Temperature
21 ± 2 degrees C / 70 ±  degrees F
Stability: ±0.5ºC / hour
Positive air pressure

Humidity
less than 60%, fluctuation <10%/hour

Stray magnetic fields (whichever is less)
Less than 0.03 uT (0.3 mGauss) [Note: DC fields must change less than 0.3 mGauss]
or
Measured in an horizontal direction: Less than 3mG peak to peak ( 1 mG rms ) for mains power frequency ( 50 or 60 Hz ) and its harmonics, and less than 0.1 mG peak to peak (0.035 mG rms ) for all other frequencies. Measurements done with a spectrum analyzer (1 mG = 10-7 T)

Floor Vibration (whichever is less)
Less than 1 micron P-P
or
Less than 5.10-5 g peak to peak ( 1.8.10-5 g rms ) or 5.10-4 m/s2 peak to peak (1.8.10-4 m/s2 rms ), for all spectral components, measured with a spectrum analyzer. Displacement less than 3 μm peak to peak for all frequencies ≤ 2 Hz

Acoustic Noise
Less than 65dBf (un-weighted)
Pump room: Foam insulation noise barrier between pump room and microscope room


Further microprobe room specifications

Minimum Doorway Dimensions
900mm (W) x 2000mm (H); 35.5" (W) x 79" (H)

Electricity
Single-phase, 60 Hz, 208 VAC, + 10%. , 6KVA maximum load. Please provide a NEMA 6L-30R receptacle/plug or a disconnect box including an emergency shutdown switch.

Stability:
± 5% long term voltage stability (>5 sec)
Δ < 8% of nominal voltage, 5 s to 5 ms duration
Δ < 25% of nominal voltage, 1 μs to 800 μs duration
Frequency Stability: 60 Hz, ±5%
Distortion: < 5% THD voltage waveform

Please provide an NEC isolated ground with less than 3 ohms impedance. This ground should not be shared by other equipment, or bonded to the conduit or outlet box.

Other outlets:
Multiple single phase, 60 Hz, 117 VAC, 20A.
Three phase, 60 Hz, 117 VAC,

Anticipated plug load for scientific equipment
18A for electron microprobe
Title: Re: Planning and Design of Instrument Facilities
Post by: jon_wade on November 14, 2014, 08:29:44 am
This topic should be renamed "Most inappropriate place to shove a probe!"*

We have just purchased a new FE probe, but the room its being shoe horned in has....

the main power line running over the top
a compactor behind,
a lift shaft to the right
a rock crusher two doors down
and for good measure,  pumps in the room.

It is in the basement though, with no natural light and the instrument will, at a push just about fit (provided the carbon coater can be pushed against the far wall).  As you can imagine, I'm hoping that the room fails the manufacturers minimum specs!


* re-reading my title change, maybe it shouldn't  ;)
Title: Re: Planning and Design of Instrument Facilities
Post by: Probeman on November 14, 2014, 04:09:56 pm
We have just purchased a new FE probe, but the room its being shoe horned in has....

It is in the basement though, with no natural light and the instrument will, at a push just about fit (provided the carbon coater can be pushed against the far wall).  As you can imagine, I'm hoping that the room fails the manufacturers minimum specs!
If you absolutely must install a new instrument in an old room, well you are just "stuck". 

Here's my 2 cents: the manufacturers minimum room specs are a bit disingenuous- why?  Because instrument vendors hate to lose a sale just because the room doesn't meet minimum "specs". Mind you- these room specs really are "minimum". That is, they are the worst possible room conditions for which the vendors think they just might be able to get the instrument to pass its own performance specs, kinda, sorta, on a good day!

When designing  a new room for a new instrument, one has some possibilities to *further* improve the new instrument performance by improving the room specs beyond the "minimum" performance. For EPMA, the critical parameter is of course, room temperature control. 

When we first met with the architects to discuss the room performance specs for the various instruments in our Lokey Lab construction project, they said: "Just give us the "cut sheets".  What does this "cut sheets" mean? It means the published specs from the instrument vendors... however I said, "nope we are *not* going to use the vendor specs. We're going to use different specs- in fact, much better specs."

The upshot of it all is we now have fabulous building performance, e.g., +/- 0.2 degrees C, *all the darn time*.   ;D   See here for more details:

http://probesoftware.com/smf/index.php?topic=332.0
Title: Re: Planning and Design of Instrument Facilities
Post by: Probeman on February 23, 2015, 01:28:13 pm
Here are the acoustic panels we use in our lab:

Subject to compliance with Project requirements, provide products of the following: Wall Technology, Inc., Ladysmith. WI. Manufacturer’s representative is Jerald Schwarz, Schwarz & Associates, Renton, WA, (206) 218-3489, Jerald@div-9.com.
2.2 MATERIALS

A. Back-Mounted Wall Panels AWP-1 and Ceiling Panels ACP-5 & ACP-6: The core construction is a dimensionally stable 6-7 PCF glass fiberboard laminated with a 1/16” 16-20 pcf molded glass fiber, all covered with a specially formulated fiberglass mat. Square edges are protected with resin hardening. The acoustically transparent finish completely covers the face and exposed edges. Wall Technology “Foundations”.

See attached pdf below.

This stuff is amazingly good at sound absorption. Much, much better than foam rubber.
Title: Re: Planning and Design of Instrument Facilities
Post by: Richard Walshaw on October 09, 2015, 07:19:16 am
Hi Anette and John

Thanks for posting this info. We are starting to go through all this with architects at the moment and I'm finding your comments useful.
I agree completely with John's philosophy of not settling for the basic manufacturer room specs. You have a once in a lifetime chance to get your dream lab, you must aim high.

John - do you have measurements for vibration and EMI taken in the centre of your probe room?

Regards

Richard
Title: Re: Planning and Design of Instrument Facilities
Post by: Probeman on October 09, 2015, 09:04:56 am
I agree completely with John's philosophy of not settling for the basic manufacturer room specs. You have a once in a lifetime chance to get your dream lab, you must aim high.

John - do you have measurements for vibration and EMI taken in the centre of your probe room?

Hi Richard,
I don't have the info specifically for my EPMA lab, but the entire facility has been measured for vibration at something around 4 to 8 times better than NIST-A. The vibration survey file attached below mentions "location 3" because we didn't have room numbers in the building yet and I can't remember what location 3 was!  By the way, NIST-A is the "gold standard" for nano-tech characterization (TEM, STEM, etc).

Attached below are some files that you should also find helpful.  I also attached some files regarding separate "grounding" for the labs. This is to provide a "quiet" electrical reference ground for each instrument.

All this said, I'm sure you realize that single most important room performance specification for an EPMA lab is temperature stability.

Our temperature spec in our lab was +/- 0.25 C and we routinely monitor this in our lab and it is always +/- 0.1 C degrees. Yes, this is crazy good, but I told our mechanical engineer that I knew he wouldn't be able to reach +/- 0.25 C and he took it as a personal challenge to prove me wrong, and boy, am I happy that he did!   ;D

Remember, if the room temperature is comfortable for humans, it really doesn't matter what the temperature is, just so long as it is stable.
john
Title: Re: Planning and Design of Instrument Facilities
Post by: Richard Walshaw on March 08, 2016, 07:46:52 am
Hi

Me again - I'm expecting architects will soon ask me to justify the +/- 0.2 degC room temp control i've requested for our new EPMA room.
Does anyone have or know of data that shows machine stability is superior at this spec compared with the +/- 1degC given on the JEOL room spec sheet?

Richard
Title: Re: Planning and Design of Instrument Facilities
Post by: John Donovan on March 08, 2016, 08:08:47 am
Hi

Me again - I'm expecting architects will soon ask me to justify the +/- 0.2 degC room temp control i've requested for our new EPMA room.
Does anyone have or know of data that shows machine stability is superior at this spec compared with the +/- 1degC given on the JEOL room spec sheet?

Richard

Hi Richard,
Temperature stability is definitely essential for reproducible EPMA work.  Here are some measurements I made in my lab:

http://probesoftware.com/smf/index.php?topic=332.msg1741#msg1741

Prior to this, we had a strong diurnal signal in the x-ray standard intensities.

Ask them why they can't do an HVAC job as well as a bunch of dumb yanks!     ;D
Title: Re: Planning and Design of Instrument Facilities
Post by: Richard Walshaw on March 08, 2016, 08:22:53 am
Thanks John

Do you have any old data describing your diurnal cycle for comparison?
I'll be sure to throw down that gauntlet as you suggest - I'm sure the engineers would love to take the bait - sadly the project is already way over budget. I don't want to move on this particular issue but I'll need to produce some numbers.

R
Title: Re: Planning and Design of Instrument Facilities
Post by: Probeman on March 08, 2016, 10:47:39 am
Do you have any old data describing your diurnal cycle for comparison?
I'll be sure to throw down that gauntlet as you suggest - I'm sure the engineers would love to take the bait - sadly the project is already way over budget. I don't want to move on this particular issue but I'll need to produce some numbers.

Hi Richard,
I couldn't be sure that the intensity drift would solely be due to temperature drift, but I will simply say, that things have definitely improved stability wise in our new lab.  But you can do the experiment yourself.  Run the same test I did by acquiring the same standards for a few days every 6 hours or so (in a PFE run) and see if you can get the same stability I showed in the link above.

That said, I only asked for 0.25 C stability, but I told the engineer he couldn't do it, so it became a point of personal pride with him to prove me wrong- and man, am I glad he did!  We are around 0.1 to 0.2 C stable all year long in the lab.

By the way, he used off the shelf commerical re-heat units from Siemens but tweaked their firmware somewhat. The engineer was David Knighton and his email address is:  dknighton@bhengineers.com  if they would like to contact him.
john
Title: Re: Planning and Design of Instrument Facilities
Post by: Anette von der Handt on June 22, 2016, 01:45:47 pm
Could you give some details on the Siemens re-heater unit (like if it is a specific model)?

Thanks!
Title: Re: Planning and Design of Instrument Facilities
Post by: Probeman on June 22, 2016, 03:22:24 pm
Could you give some details on the Siemens re-heater unit (like if it is a specific model)?

Thanks!

Our mechanical engineer on the project responds:

Quote
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 email is: DKnighton@bhegroupinc.com if you need more info.
john
Title: Re: Planning and Design of Instrument Facilities
Post by: Anette von der Handt on February 06, 2017, 01:58:16 pm
Hi,

I am in another round with the architects and thought I share some (sometimes more, sometimes less) valuable literature that I found around designing electron microscopy laboratories.

Best,
Anette


Alderson, R.H., 1975, Design of the electron microscope laboratory. In: Practical Methods in Electron Microscopy 4. American Elsevier. pp. 130.

Muller, D.A., Kirkland, E.J., Thomas, M.G., Grazul, J.L., Fitting, L. and Weyland, M., 2006. Room design for high-performance electron microscopy. Ultramicroscopy, 106(11), pp.1033-1040.

O'Keefe, M.A., Turner, J.H., Hetherington, C.J., Cullis, A.G., Carragher, B., Jenkins, R., Milgrim, J., Milligan, R.A., Potter, C.S., Allard, L.F. and Blom, D.A., 2004. Laboratory design for high-performance electron microscopy. Lawrence Berkeley National Laboratory.

Jones, L. and Nellist, P.D., 2013. Identifying and correcting scan noise and drift in the scanning transmission electron microscope. Microscopy and Microanalysis, 19(04), pp.1050-1060.

Marcelo Gaudenzi de Faria, Yassine Haddab, Yann Le Gorrec, and Philippe Lutz (2015): Influence of mechanical noise inside a scanning electron microscope. Review of Scientific Instruments, 86 (4). doi 10.1063/1.4917557.

MacLeod, B.P., Hoffman, J.E., Burke, S.A. and Bonn, D.A., 2016. Acoustic buffeting by infrasound in a low vibration facility. Review of Scientific Instruments, 87(9), p.093901.

de Faria, M.G., Haddab, Y., Le Gorrec, Y. and Lutz, P., 2015. Influence of mechanical noise inside a scanning electron microscope. Review of Scientific Instruments, 86(4), p.045105.

Iwaya, K., Shimizu, R., Teramura, A., Sasaki, S., Itagaki, T. and Hitosugi, T., 2012. Design of an effective vibration isolation system for measurements sensitive to low-frequency vibrations. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 30(6), p.063201.

Xin, Y., Kynoch, J., Han, K., Liang, Z., Lee, P.J., Larbalestier, D.C., Su, Y.F., Nagahata, K., Aoki, T. and Longo, P., 2013. Facility implementation and comparative performance evaluation of probe-corrected TEM/STEM with Schottky and cold field emission illumination. Microscopy and Microanalysis, 19(02), pp.487-495.


Some information on anti-static flooring
https://www.staticworx.com/articles/article-compliance-mistakes-selecting-esd-tile.php
http://www.flooringtech.com.au/unit13_esd_floors/content/lesson1_static_electricity_in_floors.htm
Title: Re: Planning and Design of Instrument Facilities
Post by: Mike Matthews on March 28, 2017, 01:11:18 pm
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
Title: Re: Planning and Design of Instrument Facilities
Post by: Probeman on March 28, 2017, 01:43:37 pm
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:

Quote
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
Title: Re: Planning and Design of Instrument Facilities
Post by: Anette von der Handt on March 28, 2017, 02:53:24 pm
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.

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
Title: Re: Planning and Design of Instrument Facilities
Post by: Mike Matthews on March 29, 2017, 09:52:17 pm
Thanks guys and gals, all very useful info. I'll certainly look up the Muller paper.
Title: Re: Planning and Design of Instrument Facilities
Post by: dawncruth on January 28, 2020, 04:58:59 pm
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

Title: Re: Planning and Design of Instrument Facilities
Post by: JonF on January 30, 2020, 12:29:06 am
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.

Title: Re: Planning and Design of Instrument Facilities
Post by: dawncruth on January 30, 2020, 03:48:34 pm
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!
Title: Re: Planning and Design of Instrument Facilities
Post by: Probeman on January 31, 2020, 10:00:21 am
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!
Title: Re: Planning and Design of Instrument Facilities
Post by: dawncruth on April 16, 2020, 03:17:57 pm
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  :D
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?
Title: Re: Planning and Design of Instrument Facilities
Post by: Anette von der Handt on April 16, 2020, 04:57:25 pm
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.
Title: Re: Planning and Design of Instrument Facilities
Post by: sem-geologist on April 18, 2020, 09:32:31 am
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).
Title: Re: Planning and Design of Instrument Facilities
Post by: sem-geologist on April 18, 2020, 09:42:18 am
... 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)
Title: Re: Planning and Design of Instrument Facilities
Post by: Probeman on April 18, 2020, 10:51:48 am
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.