All NMR spectrometers in Penn Chemistry NMR Facility contain super conducting NMR magnets; once energized these magnets remain at desired field (6-21 Tesla) for many years. These magnets are filled with huge quantities of super cooled cryogens (liquid helium and liquid nitrogen). The magnetic fields of these super conducting magnets are quite strong (approximately 50000 times stronger than earth’s magnetic field). In addition, NMR spectrometers use very high electrical voltages/RF sources.

For safety, it is important to keep all metallic objects (such as chairs, tools, keys, paper clips, etc.) and computer storage media (i.e. floppy disks, magnetic tapes, etc.) a safe distance away from the magnet. Safe distance is determined by the type of magnet and its magnetic field (fringe field) and a terminology known as 5 Gauss line. Magnetic field is active along horizontal and vertical lines. Generally it is specified by magnet manufacturer during the supply of the magnet and most of the NMR laboratories are built according to such specifications. For safety, it is advisable not to bring any metallic objects at least 3 feet for 300-400 MHz magnet and 4 feet for 500-600 MHz magnet (in case of unshielded magnets). All Penn Chemistry NMR Facility spectrometers are unshielded at present.

Note: Bringing metallic objects too close to the magnet Dewar is a dangerous situation and can cause the magnet to quench.

Although a magnet quench is quite rare in occurrence, it is important to recognize the potential suffocation hazard during a quench arising from the rapid release of a large volume of helium gas from the Magnet Dewar over the course of several minutes. If you think the magnet is quenching, leave the room immediately!

Also, do not lean on or touch the magnet dewar when inserting or removing sample tubes. Leaning on or touching the magnet dewar will introduce waves in the liquid helium pool in which the superconducting coil of the magnet is immersed. If these waves are of sufficient intensity, the superconducting coil will make thermal contact with dewar wall and result in a magnet quench.

Broken Sample Tube

Broken glass and spilled chemicals on the NMR room floor represent a hazard to those responsible for the care, maintenance, and service of the spectrometer.

• If a sample tube is broken in any of the NMR laboratory, first clean up all the broken glass and spilled chemicals and then notify NMR Facility staff. If broken sample tube contains hazardous chemicals, immidiately contact Penn Health and Safety for help and directions to clean.
  
  
• If a sample tube is broken inside the magnet bore notify NMR Facility Staff immediately so that the probe and magnet bore can be cleaned before permanent damage occurs to these components.