SLAC Electrons: Mass, Velocity & EM Energy

[HarryWertM]

In the Stanford Linear Accelerator electrons are accelerated thereby gaining mass; velocity; and undoubtedly radiating EM energy. I'm sure they have grounded shielding to avoid loud pops on local AM radio.

But suppose they decelerate electrons the same way - thereby radiating EM energy; losing velocity; and losing mass?? How is energy then conserved?? By creating negative or imaginary mass?? Or do electrons gain even more mass during deceleration, creating "heavy electrons"??

 

[Drakkith]

The electrons are decelerated against an electric or magnetic force. They exert pressure and force against the magnets to do this. Also, when they radiate energy, that energy has mass. Energy and mass are conserved.

 

[HarryWertM]

So after deceleration, the electrons would have their original "rest mass"?

 

[Drakkith]

So after deceleration, the electrons would have their original "rest mass"?

That is exactly correct.