7T How To: Quench
What should you do if the magnet quenches?
Do not panic.
Prop open the door between the operator room and the hallway.
Prop open the door to the magnet room.
Instruct any person in the magnet room to leave immediately and help them if it is safe to do so.
Evacuate all personnel from the area until the air is restored to normal.
When should you use the quench button?
The quench button is to be used only in the case of an emergency in which a person is injured and the only safe way to avoid further injury is to decrease the magnetic field strength of the magnet.
What happens when the quench button is pushed?
Pushing the quench button will cause the magnet temperature to rise slightly. The liquid helium that cools the magnet will rapidly boil off. The quench pipe above the magnet is designed to allow the helium vent outside of the building. If the quench pipe fails there is a danger that the magnet room will fill with helium and that the oxygen in the room will be displaced, which could cause injury or death for anybody in the magnet room or the console room during a quench.
Why is the quench button only used in case of emergency?
Quenching the magnet can be dangerous due to the rapid boil off of helium which creates dangerously high pressures and could displace oxygen from the room. A quench could cause permanent, irreparable damage to the magnet. If the magnet survives the quench it will have to be recharged which is costly and time consuming.
Where are the quench buttons?
The 7T has two quench buttons. One button is mounted on the wall near the scanner in magnet room. The second quench button is located in the equipment room next to the magnet room. Most users will not have access to the equipment room.