Undergraduate Research at Jefferson Lab

Determining Electron Beam Energy through Spin Precession Methods

Student: Gina Mayonado

School: McDaniel College

Mentored By: Douglas Higinbotham

Nuclear physics experiments at Jefferson Lab require that the beam energy of the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator be known to 0.01%. The g-2 spin precession of the electrons as they circulate in the machine can be used to determine the beam energy without relying on the absolute calibration of magnets and devices required for other methods. The precision of this approach needed to be fully investigated. Spin precession methods were investigated by writing an Apple application to calculate the precession, as well as study effects, such as synchrotron radiation. It was found that the electron beam energy could be determined through these methods with precision at the 0.01% level. These results also incorporate energy loss due to synchrotron radiation, giving more accurate energy values than were previously calculated. This investigation shows that the spin precession method is a reliable and useful way to determine the beam energy.