Calculations indicative of the power loss for 75 in.radius gap splitters are given.

The geometry of the magnetic pole structure in the cloverleaf cyclotron suggests the use of three dees excited by three phase rf placed in the valleys out of the way of the beam. Experience with the model machines indicates that it is desirable to be able to vary the phase angles between the three dee voltages through 30 or 40 degrees and to be able to maintain them at any given value within plus or minus one degree. It is desirable, also, to be able to vary the phase angle independently of the amplitude of the dee voltages. There are several possible ways of meeting these requirements. The one which was chosen appears to be the most flexible and to best meet the problems presented by the center geometry of the machine.

One of the oldest properties of electrons is their emission of x-rays (discrete and continuous spectra) when impinging on matter. Cloud-chamber tracks show light ionization, and considerable multiple scattering, except for fast electrons. Tracks are long and range indefinite.