How Our Cyclotron Works


A Cyclotron is a form of a particle accelerator used for the production of nuclear medicines.  Our cyclotron is a GE PETtrace 16MeV self-shielded negative Ion accelerator.  There is not much to see when the radiation shield doors are closed, but when the system is opened it reveals many interesting subsystems with an array of sciences and technologies required to produce the radionuclides used in our PET Drug manufacturing processes. 

Inside of a GE PETTrace Cyclotron

Here you can see inside of our cyclotron vacuum chamber where the creation and acceleration of the negative Ions occurs.   Hydrogen gas enters the center of the chamber into an Ion source.  Hydrogen gas, having one proton and one electron is neutrally charged meaning it alone cannot be influenced by electro or magnetic energies.  The hydrogen gas undergoes ionization (addition of an electron to the hydrogen atom) by way of high voltage placed onto cathodes contained within an anode configuration within the Ion source.  Now that the ions have a net negative charge (negative ion) they can be manipulated with electro (Radio Frequency) and magnetic energies generated from other cyclotron subsystems.  Vacuum is pulled from the accelerator chamber to maximize the efficiency of a beam of negative Ions from the center of the chamber to the outer region where the beam of Ions are aimed at targets.  

Vacuum Subsystem

You cannot necessarily see them, but to a cyclotron straight unfiltered atmosphere is polluted with all kinds of things that get in the way of desired negative ions needing a clear shot from the center of the vacuum chamber to the targets.  A combination of diffusion and rotary mechanical pump technologies are used to pull high vacuum from the accelerator chamber effectively removing a fair amount of stray particles from the beam pathway.  This done to maximize the efficiency of a beam of negative Ions from the center of the chamber to the outer region where the beam of Ions are aimed at targets to produce the radionuclides.  

Control System

The cyclotron requires an array of subsystem controls which are placed away from the radiation field in order to protect sensitive electronics, ensure adequate cooling, and sufficient access space for operators and maintenance staff.  These subsystems include a Radio-Frequency Power Generator capable of producing up to 15kW of RF power used for negative Ion acceleration, a 500Amp DC Magnet Power Supply used for Ion beam steering, a 5000VDC 1A Ion Source Power Supply used to ionize hydrogen atoms, a Vacuum Control System which monitors vacuum gauges and controls vacuum pumps and valves,  and a main control system where a good portion of accelerators control and feedback signals are routed and processed in order to make everything work as designed.

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