12-Inch Cyclotron

12-Inch Cyclotron

Author: Tim

In the fall of 1995 Tim had the idea to build a cyclotron. In September 1999 it achieved its first beam. In 2001 it was moved into the Modern Physics teaching lab at Rutgers University’s Physics department. In 2016 it was moved to a dedicated undergraduate accelerator teaching lab at the University of Maryland.


Because the 12-Inch Cyclotron has its own website, we will only give a brief overview of the machine. This site will host the experiments performed with the cyclotron.

The cyclotron chamber removed from the magnet and opened for viewing while at Rutgers.
Cyclotron in operation at Rutgers. Note phosphor screen target seen in the chamber window.
The 12-Inch Cyclotron chamber opened.
The 12-Inch Cyclotron in operation at the University of Maryland, 2020.
The rear side of the 12-Inch Cyclotron showing the RF and vacuum systems.
Other view of the rear side, with the “RF box” in the foreground.
Take the lid off and look inside the RF box.
The 12-Inch Cyclotron chamber open on the bench for ion source rebuild.
PIG Ion source disassembly.
PIG Ion Source components disassembled and cleaned for rebuild.
12-Inch Cyclotron’s PIG Ion Source reinstalled and in operation.
Typical view through the rectangular port during normal operation. One can see the purple glow surrounding the ion source in the center of the chamber, and the bright green vertical beam spot on the phosphor screen inserted about one half the way in from the maximum ion source radius of 5 inches.
If the chamber pressure is high enough (really too high for useful operation) the plane of the circulating beam can be visually observed.
12-Inch Cyclotron’s deflector assembly on the bench, phosphor target to the right.
Same view of the deflector channel, but with it installed in the cyclotron chamber. An intense beam spot can be seen making it to the end of the deflection channel.
Close-up view of the phosphor target, viewing two spots of the partial nth and all nth+1 turns.
Another closeup, but seeing the effect of an aperture plate installed just before the deflector.
Deflection channel after a long run showing beam burn-in on phosphor screen.
The collection of pole tips, upper left: good WF pole tips, bottom left: bad WF pole tips, top right: AKG270 AVF spiral pole tips, and bottom right: radial sectored AVF pole tips.
Axial betatron motion imaged.
Betatron motion with bad WF pole tips showing Walkinshaw resonance blow up on the right.
Control console of the 12-Inch Cyclotron.
Example of one of the 12-Inch Cyclotron’s PLC touch-screen displays.
Two-week cyclotron class at USPAS during 2015 summer session.
A tour of the 12-Inch Cyclotron’s components, subsystems, and operations.