Cold Head FAQs
Commonly Asked Questions
What is a cold head?
Inside the MRI is a cooling system containing liquid helium keeping the magnet cool. When the helium is exposed to increased temperatures is turns from liquid to gas. Inside of this cooling system is a part called the cold head which re-condenses the helium gas to liquid to prevent it from entirely burning off.
What is Boiloff?
Inside of the MRI you have helium in liquid boils at 4.2Kelvin
Average lifespan of a cold head?
The typical lifespan of a cold head is 28-32 months. Refurbished 3 – 4 years and new 4 – 5 years.
How can you extend the life of your cold head?
Ensuring that there is stable power and stable chillers will help to extend the life of your cold head. Performing regular chiller service will also help to extend the life of your cold head.
What is the cost?
The typical cost of a MRI cold head from the manufacture is $5,500.
The typical cost of a refurbished cold head is $4,500.
What composes a Cryosystem?
A Cryosystem is composed of a compressor, flex lines, and the cold head.
What is the compressor refurbishment process?
The process to refurbish a compressor includes absorber replacement, component level repairs, heat exchanger cleaning and oil change. The system gets fully pumped out followed by performance testing and a system check.
Top 4 ways to know your cold head could fail
Elevated magnet pressure: The normal range on a GE CXK4 is 4psi but once it goes above 5 the MRI can start losing helium.
Boiloff: If you start to see Helium loss or elevated/acceleration of boiloff on a 10k system.
Abnormal noise: If the MRI moves from its gentle chirp to a banging or grinding (mechanical noise)
Elevated cold head temperatures: Temperatures start or continue to rise. In order to see that you need to have a remote monitoring system in place