NOISE FIGURE 437 



10.5 Noise in Transverse-Field Tubes 



Traveling-wave tubes can be made in which there is no longitudinal field 

 component at the nominal beam position. One can argue that, if a narrow, 

 well-collimated beam is used in such a tube, the noise current in the beam 

 can induce little noise signal in the circuit (none at all for a beam of zero 

 thickness with no sidewise motion). Thus, the idea of using a transverse- 

 field tube as a low-noise tube is attractive. So far, no experimental results 

 on such tubes have been announced. 



A brief analysis of transverse-field tubes is given in Chapter XIII. 



