1) What is the absolute minimum fixed ceiling height requirement
for 600 MHz magnet installation?
2) Does anyone have any experience with using a raised flooring
system with this size system (or any)? The plan would be to lower the
floor so the magnet would sit on the concrete, but use a raised flooring
system to form the "pit" and therefore raise the console.
3) Does anyone out there think you could site a 500 and a 600 in a 27 ft
X 30 ft room? How many high resolution high field systems can you site in a
limited space? I have 2 narrow-bore 300's and a 200 in a 20 x 30 space,
and a 360, 500, and 400 in a 30 x 30 space. Personally, I think a 600
should have its own room, any other opinions/experience?
4) The room would be a building next to a pedestrian walkway which
would also have maintenance trucks, etc. Any problems anticipated?
=========================================================================
THE ANSWERS: I have edited some of the replies.
======================================================================
Date: Thu, 24 Feb 1994 12:39:15 -0600
To: mainzv (Vera Mainz)
From: cgregory@uiuc.edu (Carl Gregory)
Subject: Re: Siting a 600 magnet
Vera - just a couple random thoughts....
> 1) What is the absolute minimum fixed ceiling height requirement
>for the system?
>
> I realize we should be able to get (1) from the siting specifications
>from the manufacturer, but we are a little worried since I have not personally
>demo'ed a 600, hence have no personal experience. As another random question
Not exactly apropos, but the Varian site-planning guide for our 500 (Oxford
magnet) gave a 5g line specification that was fairly accurate as measured
with a good magnetometer after installation. So maybe you can trust the
manufacturers information. I think the specs for a 600 are also in the
same book - I can get a copy of the drawing for you if you like. We were
limited on ceiling height by the 5g line because COM did not want to have
to post the conference room upstairs for magnetic field hazards. If that
is not a concern, you can certainly get by with a much lower ceiling.
> 2) Does anyone have any experience with using a raised flooring
>system with this size system (or any)? The plan would be to lower the
>floor so the magnet would sit on the concrete, but use a raised flooring
>system to form the "pit" and therefore raise the console.
>
I understand that "computer floor" is available in an aluminum frame/base.
I suppose this could be used for your purposes. However, it seems to be
quite expensive, from discussions we have had about using it around the
magnets in the Beckman institute. The standard removable floor tiles (2ft
square) we have up here are about half iron by weight - the rest is some
sort of cement composite. Of course, you could probably do a concrete pit
like the one in Med Sciences with no trouble.
Carl Gregory
=========================================================================
Date: Fri, 25 Feb 94 17:01:33 EST
From: "Bill BUBB" <bubb@atp.biochem.su.oz.au>
To: mainzv
Subject: Installation Queries
We installed an AMX-600 in a room with a 3.7 m ceiling which was fairly tight.
You need to be careful that the height needed for assembling the magnet is
greater than that for helium fills. You might find the story of our installation
interesting - if you have back copies of the TAMU Newsletter, we sent a note on
May 16, 1990 which should have appeared in the June issue. Let me know if you
can't locate it and I'll fax you a copy.
They have a 500 and 600 in the same room at the BRI in Melbourne. Ray Norton
(details below), who is the chief scientist in the lab and who I don't think is
on the mail list, might be able to help you.
=================================================
NMR Laboratory,
Biomolecular Research Institute,
381 Royal Parade, Parkville 3052, AUSTRALIA.
Ph: +61 3 903 9650
FAX: +61 3 903 9655
EMAIL: ray@mel.dbe.csiro.au
=================================================
********************************************************************************
Bill Bubb
NMR Laboratory Manager
Department of Biochemistry
University of Sydney
Sydney NSW 2006
Australia
Fax: +61-2-692-4726
E-mail: wab@biochem.su.oz.au
********************************************************************************
=========================================================================
Date: Fri, 25 Feb 94 10:52:43 -0500
From: vnmr1 <vnmr1@nmribm.chem.rpi.edu>
To: mainzv
Subject: Re: Siting a 600 magnet
Sounds like you are going to have great fun with this new 600 and
new building. I have nothing to offer on the 600 since we only have a
500. My advice is probably obvious but I would work very closely with the
appropriate contacts from your NMR vendor. Try to put them in direct
contact with your achitects and engineers to plan your space and placement
of utilities. Make sure you stay in the loop as well so you know what is
being cooked up and the space will be planned well from a user's point of
view as well. If you do anything to violate the minimum requirements that
the vendor finally gives you, they will have a convenient excuse if some
performance specifications are not met. Good Luck. Herb Schwartz
RPI
=======================================================================
Date: Fri, 25 Feb 94 08:06:50 MST
From: csn.org!colorado!software!cindy (Cynthia Ridenour)
To: mainz
Subject: 600 NMR System
When I was a student at Colorado State University, our research group had a 600
MHz instrument installed in the basement of the Chem. building. We built a pit,
for the magnet, but not to sit the magnet itself in. Rather, the magnet sat
on the same level as the rest of the room. It was installed with short legs,
and the pit below it was about 2 feet by 2 feet by 2-3 feet deep, and allowed
us to insert the bottom-loading probes into the magnet. This design actually
worked quite well. In our situation, I believe that it was the least
costly alternative for solving the height problem.
This 600 MHz system being in the basement near several shops, we found that
magnetic dust was a problem. If you can find a magnetic doormat to collect
magnetic debris, or prevent access from your pedestrian and maintenance truck
path, you can probably reduce the "magnetic dust" problem.
Cindy Ridenour
Otsuka Electronics
Chemagnetics Product Group
cindy@otsuka.com
====================================================================
Date: Fri, 25 Feb 94 08:33:31 CST
From: wchutt@alex.monsanto.com (Bill C Hutton)
To: mainzv
Subject: Re: Siting a 600 magnet
About six years ago we installed a 500 MHz system in a lab where we
were already using a 400 MHz spectrometr (it was loaner until the 500
arrived). Through a series of coincidences, the 400 magnet center
happened to be exactly at the 5 gauss line of the 500. As the 400 was
being used daily, and the 500 was Varian's first, we knew we would need
the 400 to be functional for a significant period of time.
As the 500 magnet was energized I monitored the H-1 lineshape (CHCL3)
onthe 400. I would perform minor shimming from time to time. I found
there was very little difference in the room temperature shims. The 400
magnet and 500 magnets were not be very sensitive to each others
presence. When the 400 was deenergized the 500 was trivialy reshimmed
(room temperatures only).
In our experience then we can tell you if the magnets are seperated by
the 5 gauss line of the largest magnet you should have no trouble. We
have never had magnets closer than a 5 gauss line seperation.
I hope this single data point helps.
======================================================================
From: I H Sadler <ihs01@castle.edinburgh.ac.uk>
Subject: Re: Siting a 600 magnet
To: Vera Mainz <mainzv>
Date: Fri, 25 Feb 94 9:16:33 GMT
In reply to your query about siting of instruments - Oxford instruments
have told us that the magnets CAN be sited "close" as long as the centre
of the smaller one is outside the 5 gauss line of the larger. (and if
they are the same size then the centre of one must be outside the 5 gauss
line of the other)
Ian Sadler.
====================================================================
Date: Thu, 24 Feb 94 21:13:51 -0500
From: barry@primer.med.yale.edu (Barry Schweitzer)
To: mainzv
Subject: Re: Siting a 600 magnet
>From my investigations, it sounds like 12 ft is the minimum height
requirement for a 600 magnet (an Oxford magnet, anyway). But, like
you, I've never demo'd one myself. One thing that has always puzzled
me a little about putting the magnet in a pit (or raising the floor
like you are proposing) is why not just use a ladder to get to the
top of the magnet? In our 500 room, we have built several wooden
steps (using brass fasteners) that allows the shorter users to
put their samples in and our rather petite technician to do her fills.
It cost about $10 to make. Is there some other advantage to a pit
that justifies the cost? Maybe it is just to get around the requirement
for a 12-13 foot high ceiling (our building is a single story so
this isn't a problem for us) .... Anyways, I may also have a similar
problem as you with pedestrian and vehicular traffic near the 600 room,
so I would like to hear the responses you get about that concern.
I also don't know about putting a 500 and a 600 in the same room.
My gut feeling is that you could. A 600 requires 20 X 20 feet in order
to protect the console and computer from the field. A 30 X 30 ft room
should be large enough to place the console far enough away with each
magnet in separate corners. The vendor (I'm assuming this is Varian
) should be able to tell you for sure as well as actually mapping the
fields so that the superconducting shims are still properly calibrated.
Barry Schweitzer
LMP 3094
Department of Pediatrics
203-785-6780 Fax: 203-785-7194
barry@primer.med.yale.edu
====================================================================
Date: Fri, 25 Feb 1994 10:06:07 +22306620 (CST)
From: Thomas Lyttle <lyttle@rs5.tcs.tulane.edu>
Subject: Re: Siting a 600 magnet
To: Vera Mainz <mainzv>
I'm not sure about the minimum ceiling height, but I have seen a
600 on a raised floor "pit" (I just can't remember where at the moment). That
works quite well. I also do not see a major problem with a 500 and 600 in
the same room as long as the magnets are at opposite corners. Assuming it
won't be a wide bore 600, the stray field shouldn't be too bad, but, as
you know, 600's have significant stray fields, so you want the magnet as
far from moving objects as possible. Also watch out for those vibrations!
As you know, I helped Georgia and Northwestern buy their 600's.
I found that both Varian and Bruker have good siting guides, which you should
get ahold of as soon as possible. Hope to see you soon. Tom
=======================================================================
Date: Fri, 25 Feb 94 11:18:38 EST
From: rolf tschudin <tschudin@speck.niddk.nih.gov>
To: mainzv
Subject: throes
1. We have a 600 and a 500 in a Lab 27 x 20 ft with a 122"
ceiling. The 600 magnet sits on a hydraulic lift stand (Bruker).
The floor of the room above has a shield to cut down the stray
field, which was installed during the remodeling. Across the
hallway (8 ft wide) we have 2 500's in the same situation.
2. Another 600 sits in a room with the same ceiling, but the
magnet sits in a pit 7 x 9 feet, 4.5 ft deep. If we had to do it
over, we would make the pit at least 8 x 10, 6 ft deep. Some
shielding above would have helped, we have had problems with
color monitors in the room above.
3. A third 600 is in a room with a 207" ceiling. No shielding
is installed, and we have had trouble with a color monitor above.
4. The magnet centers are about 12 to 15 ft from frequently
used hallways.
Rolf
====================================================================
From: gregq@mcs.com (Gregory Quinting)
Subject: Re: Siting a 600 magnet
To: mainzv (Vera Mainz)
Date: Fri, 25 Feb 1994 23:40:49 -0600 (CST)
At Colo. St. Univ. they sited the 600 in the basement where it was impossible
to raise the ceiling. Instead they used a concrete saw and jackhammers to
make a hole in the rather thick floor. This allowed them to use normal
length legs on the magnet, or perhaps even short legs. The hole allows
sufficient volume to change probes and preempts the need for a magnet lift
system.
You may want to contact Bruce Hawkins or Gary Maciel for further details.
Greg Quinting
Sherwin-Williams Automotive, Chicago
(gregq@genesis.mcs.com)
==========================================================================
Date: Fri, 25 Feb 94 12:21:03 PST
From: yoti@aku.ucsc.edu (Thomas Schleich)
To: mainzv
Subject: Re: Siting a 600 magnet
Professor M. Sogami of Fugita Medical University in Japan has a raised floor/
magnet pit setup for a Bruker 500. I have seen the facility and it appears tp
work well. This facility also overlooks a lovely Japanese garden which may
impart the right "karma" for his experiments. Prof. Sogami does not have an
E-mail address, as far as I know. If you need a complete mailing address I can
provide it.
---Tom Schleich
UC Santa Cruz
===========================================================================
Date: Wed, 2 Mar 1994 22:24:08 -0600
From: Gerald Pearson <gpearson@umaxc.weeg.uiowa.edu>
To: mainzv
Subject: Re: Siting a 600 magnet
VM> 1) What is the absolute minimum fixed ceiling height requirement
VM> for the system?
I think that fringe-field considerations are the most severe limitations
for this magnet, unless you are on the ground floor and there is no floor
above you.
I. I would recommend an absolute minimum floor-to-ceiling distance of 15.5',
and I think it would be highly desirable for this distance to be 18.5' or
greater. This is based on the following considerations.
1. Our concrete ceiling is about 18.5' above the floor of the magnet pit.
I deliberately chose the depth of the pit to put the vertical 5-gauss line
just at the floor surface of the room directly above the magnet.
2. This also gives more than ample headroom for everything else.
3. My own view is that shrinking the headroom below 18.5' would begin to
put restrictions on possible uses of the room immediately above the magnet. 5
gauss is enough, for example, to distinctly affect a color monitor, so it must
be magnetically shielded and degaussed. (We've shielded one PC and two
workstation monitors.)
4. Shrinking the headroom below 15.5' would start to put fields above 10
gauss into the room above the magnet, which could conceivably have legal
liability ramifications if that room is ever accessible to the general public
at any time.
5. Even our 18.5' headroom puts _some_ restrictions on the use of the
room above, and rooms adjacent to it. For example, no one in their right mind
would want to put any low energy electron diffraction apparatus there. (This
issue _did_ come up here, I worked with the new faculty member to roughly
calculate fringe fields, and she wound up getting her planned research lab
room assignments changed.)
6. After talking over the phone with someone at Oxford Instruments for
about 20 minutes one day before our 600 was installed, I became convinced that
proper design and installation of magnetic shielding in the ceiling would be
_so_ expensive that we simply didn't have an economically viable alternative
to moving the magnet below existing floor level. In your case, it's probably
much cheaper to change the plans _before_ construction than to properly shield
the room magnetically _after_ construction. Call Oxford if you need details
to back up this assertion to architects, contractors, or accountants. Oxford
has designed magnetic shielding for existing rooms in hospitals for some MRI
installations, _but_ _it_ _aint_ _cheap_.
II. To get the He stinger into the can, we need a bare minimum of 14' from
pit floor to ceiling. The tops of the He fill tubes on the can are about 10'
higher than the floor of our pit. When we transfer liq He into the auxiliary
can (old design), we screw an extension onto the stinger to reach lower into
_that_ can, in which case we need at least 4' of clearance above the He fill
port for the auxiliary can.
III. You need about 12' of clearance from the bottom of a 250 l storage dewar
to the ceiling, so you can get the stinger in. This is actually the most
critical restriction for us outside of stray magnetic fields, because 12'
above floor level is ~17.5' above the floor of the 12' X 12' pit in which our
600 magnet resides.
IV. Check with the vendor about clearance needed for setting up the magnet.
In our case, we had more than enough room.
VM> 2) Does anyone have any experience with using a raised flooring
VM> system with this size system (or any)? The plan would be to lower the
VM> floor so the magnet would sit on the concrete, but use a raised flooring
VM> system to form the "pit" and therefore raise the console.
We didn't do it this way, but I met a guy at a Bruker Users Conference
several weeks ago who works in a lab where _exactly_ that was done, with a
Bruker 600. I think he said the raised floor, etc., is all aluminum. I
gather it works quite well. You might want to ask him about some details:
Alexander Kurochkin The University of Michigan
Biophysics Research Division 930 N. University, 4012 Chem.
Ann Arbor, MI 48109-1055 Phone: (313) 763-0329
Fax: (313) 764-3323 E-mail: alex@moe.biop.umich.edu
As far as how high off the "pit" floor the raised flooring should be, I
would think 5.5' would work out well. Our pit floor is about 5.5' below the
wood platform which covers half our pit. This distance makes He fills quite
convenient, allows you to put NMR sample spinners into the probe without
stooping over too much, and doesn't force you to squat down _too_ far on those
occasions when you need to do something under the platform.
VM> Personally, I think a 600 should have its own room, any other
VM> opinions/experience?
We were "conservative", and made sure the 5-gauss line from the 600 MHz
magnet did not penetrate outside of the walls & ceiling of the room.
According to Oxford specs, the ellipsoidal surface of 5-gauss field strength
is 3.6 m horizontally from the center of the magnet, and 4.8 m above the
center of the probe (which is roughly a meter above the pit floor). This puts
the 600 in an existing 24' X 24' room all by itself. I think I'd want a
distinctly larger room, if a second magnet were going in there.
VM> Also, currently, the room would be a building next to a pedestrian
VM> walkway which would also have maintenance trucks, etc. Any problems
VM> anticipated?
Hmmm... A couple years after our 600 was installed, architectural
services had some contractors tear out a little bit of hillside & install a
parking lot just outside the room. They consulted with us _after_ I noticed
what was starting to occur outside, and made some phone calls. We haven't
noticed any problems yet. Our situation is:
1. the fringe field just outside the window is almost exactly 5 gauss,
2. there's ~7' of buffer landscaping (shrubs) from the bldg. to the edge
of the parking lot, &
3. only motorcycles are "allowed" to park at the bldg. edge of the lot --
no cars, trucks, etc. But both trucks and autos are want to illegally park
there anyway!
4. We haven't yet noticed any problem even with our wide-bore 300, which
is closer to the outside wall & generates a fringe field slightly >10 gauss
just outside the wall. On the other hand, that magnet is located closer to
the end of the building, where cars & trucks are much less likely to
[illegally] park.
5. A guy from the Health Protection Monitoring office in the University
was just over last Monday to check the fringe fields, and he measured the 5-
gauss line for the 600 magnet to be within inches of where we calculated it
should be. He's recommending posting a warning sign about pacemakers in the
small outside area closest to the 300 wide bore where the field reaches or
exceeds 10 gauss. We're currently going around & around with Architectural
Services and the Parking & Transportation Department about keeping trucks and
cars from illegally parking in the "motorcycles only" area.
Moral of the story:
1. Keep any public area below 10 gauss to avoid potential liability
issues, even if for no other reason. Myself, I think the better part of valor
is a design limit of 5 gauss. The guy from Health Protection said that some
older pacemakers get flaky at 26 gauss, that he's not aware of any law about
static field limits, but that there _is_ a recommended guideline about keeping
the static fields below 10 gauss in publicly accessible areas.
2. I would want to make sure that it's _physically_ _impossible_ for any
large vehicle to come any closer than where the fringe fields are just over 1
gauss -- about 1.5 times the distance to the 5-gauss line = 1.5 X 3.6 meters
= 5.4 meters. Signs can and will be ignored.
Maybe I'm being an old worry wart -- maybe you could get away with big
vehicles coming closer without the spectrometer performance being affected --
I don't know how close a truck has to come before the NMR line broadens by 0.1
Hz, or the lock hiccups every time the truck moves. But I'd rather be safe
than sorry. I _have_ heard that problems have been observed when an NMR
spectrometer room was next to an elevator shaft, and I would think that a
truck is bigger and has more steel in it than any common elevator. And I'm
sure you've heard the one about the NMR spectrometer room which was too close
to a tunnel through which subway trains run.
Finally -- this is obvious, but I'll say it anyhow -- IMHO:
You don't want anyone doing any future maintenance or repair work directly
above an energized magnet, if you can possibly avoid it. Contractors &
architects have a habit of doing things the obvious, easy, standard way --
which is not necessarily best for the new home of an NMR magnet. Make sure
that _everyone_ understands that _nothing_ should be on the ceiling in an area
>=100 square feet immediately above the magnet(s) -- including light fixtures,
electrical wiring, air lines, pipes of any kind, and duct work. And someone
should watch 'em like a hawk, to make sure that some crucial pieces of
information don't fall through the cracks or get garbled somewhere along the
line: architect --> contractor --> subcontractor --> straw boss --> worker.
Hope this helps. -- Gerry
===========================================================================
Date: Fri, 4 Mar 1994 09:47:24 -0600
From: Gerald Pearson <gpearson@umaxc.weeg.uiowa.edu>
To: mainzv
Subject: 2nd try
Correction to 1-Gauss distance calculation
Vera, I blew one of the numbers in my calculation of the distance to the 1-
Gauss line:
> 2. I would want to make sure that it's _physically_ _impossible_ for
> any large vehicle to come any closer than where the fringe fields are just
> over 1 gauss -- about 1.5 times the distance to the 5-gauss line
> = 1.5 X 3.6 meters = 5.4 meters. ...
The correct factor is 1.71, not 1.5: Dipolar field strength varies as the
inverse cube of distance. If we make the approximation that the fringe fields
at and beyond the 5-Gauss distance are purely dipolar, the 1-Gauss circle
would have a radius of
(5 Gauss / 1 Gauss)^0.333333 * (5-Gauss distance)
= 1.71 * 3.6 meters = 6.156 meters = 20.2 feet.
BTW: It might be worth while for you to do a similar calculation for your
other magnets. I think narrow-bore magnets up to 360 MHz are probably all OK.
The fringe fields of a wide-bore magnet reach out farther than those of a NB.
A 500?? I'm not sure. I suspect than many 500's might generate stronger
fringe fields than most people think -- particularly vertically! Before we
installed our 600, it never entered our minds that the vertical distance might
ever be an issue.
-- Gerry
=========================================================================
Date: Fri, 11 Mar 94 09:43:28 EST
From: "Dr. Thomas Mareci" <thmareci@ufnmr.health.ufl.edu>
To: mainzv
Subject: 600 installations
A colleague of mine (John West) forwarded your request for information
on installations of 600 MHz NMR systems. We recently installed a Varian Unity
600 (last October) within an existing building in the Health Sciences Center
of the University of Florida. Several critical site requirements must be
kept in mind.
1. Minimum ceiling height to install the magnet.
Check with Oxford Instruments (usual supplier of magnet) for
exact specs. In our installation we needed at least 12 feet
height over a 4 x 6 foot area to install the hoist to lift
the 1000 kg magnet into place. This 12 ft height also allows
transfer of cryogens.
2. Air conditioning to +/- 1 degree C.
We installed a seperate 'computer' room AC unit next to the
magnet room to control the temperature within the magnet room.
However, this can cause problems (see next comment).
3. Anti-vibration system required.
These magnet systems are very sensitive to vibration. The
AC unit we installed vibrates and we detect this as 50 Hz
sidebands (at the level of the C-13 satellites) in our spectra.
We can TMC anti-vibration legs and they are being modified to
remove this vibration (a retrofit from TMC).
4. Effect of the stray magnetic field.
Do not overlook the effect you may have on the environment
around you. Computer displays will be distorted (particularly
color) in ajoining room. Also I would be worried about the
movement of heavy metal in any space next to the magnet room.
5. More magnets in the same room?
I would be careful about this. Oxford claims that a 5-10 G
field at the center of a magnet (resulting from another magnet
nearby) can be handled with shims (maybe supercon shims) but
I would not count on this as you would loose the performance
of both systems if one went down. Also you must be careful
about RF harmonics.
I hope all this helps and I would suggest that you speak directly to Oxford
(or Magnex) about siting this system, in addition to the NMR vendor (Varian or
Bruker). In all we are very please with our 600 and the installation would
have gone better if we had prepared better before we started.
Tom Mareci
(904) 392-3375