The diameter of {HEAD ~ channel} 34 of magnet 36 should increase with length, as shown in FIG 1, so as to have the radius of the poles always equal to the off axis displacement of {TAIL ~ the outermost molecules} to be focused 
The diameter of { HEAD ~ channel } 34 of magnet 36 should increase with length , as shown in FIG 1 , so as to have the radius of the poles always equal to the off axis displacement of { TAIL ~ the outermost molecules } to be focused
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH