Bruker NMR AVANCE NEO Systems, User Manual, Page: 8 / 48

Introduction
8 / 48 H171764_6_001
2.2 Purpose of this Manual
The purpose of this manual is to summarize the safety considerations which apply to the
Avance system. It does not replace the individual manuals but is meant as a quick and easy
access to the relevant information concerning safety issues. As such, one copy should
always be available at the operator's desk. Please, take care that each operator of the
system is aware of the importance of this manual. In addition, each operator is advised to
read the manual in order to be aware of any safety risks which may be related to the use of
the AVANCE system.
2.3 Magnetic Safety
In terms of safety the presence of a relatively strong magnet is what differentiates NMR
spectrometers from most other laboratory equipment. When designing an NMR laboratory, or
training personnel who will work in or around the laboratory, no other feature is of greater
significance. As long as correct procedures are adhered to, working in the vicinity of
superconducting magnets is completely safe and has no known harmful medical side effects.
Negligence however can result in serious accidents. It is important that people working in the
vicinity of the magnet fully understand the potential hazards.
Of critical importance is that people fitted with cardiac pacemakers or metallic
implants should never be allowed near the magnet.
A magnetic field surrounds the magnet in all directions. This field (known as the stray field) is
invisible and hence the need to post warning signs at appropriate locations. Objects made of
ferromagnetic materials, e.g. iron, steel etc. will be attracted to the magnet. If a ferromagnetic
object is brought too close, it may suddenly be drawn into the magnet with surprising force.
This may damage the magnet, or cause personal injury to anybody in the way!
Because the strength of the stray field drops significantly as one moves away from the
magnet, it is useful to discuss safety in terms of two broadly defined regions, the inner and
outer zone. In terms of organizing a laboratory as well as defining good work practices, the
concept of an inner and outer zone is particularly useful.
The physical extent of these two zones will depend on the size of the magnet. The bigger the
magnet, the stronger the stray magnetic fields and hence the larger the extent of the two
zones. Details of stray fields for various magnets can be found in the Site Planning Guides
delivered with the BASH DVD.
2.3.1 Safety Precautions within the Inner Zone
The inner zone extends from the magnet center to the 1 mT (10 Gauss) line. Within this
region objects may suddenly be drawn towards the magnet center. The attractive force of the
magnet can change from barely noticeable to uncontrollable within a very short distance.
Under no circumstances should heavy ferromagnetic objects be located or moved within this
zone.
Any ladders used when working on the magnet should be made of non-magnetic material
such as aluminum. Helium and nitrogen dewars which are used to top up the liquid levels
inside the magnet must be made of non-magnetic material.
Do not allow small steel objects (screwdrivers, bolts etc.) to lie on the floor near the magnet.
These could cause serious damage if drawn into the magnet bore, especially when no probe
is inserted in the magnet.
Mechanical watches may be damaged if worn within the inner zone. Digital watches can be
worn safely. Of course, the precautions for the outer zone which will now be discussed must
also be adhered to within the inner zone.