High brightness sources for colliders

Different possible sources are considered, and the importance of the gun for linear colliders is discussed. Low-emittance electron guns suitable for SLC (SLAC Linear Collider) are available, and the author discusses current work that could also provide high polarization. The relative merits of gamma , e/sup +or-/, and p/sup +or-/ are discussed, along with how the Next Linear Collider (NLC) naturally provides both e/sup +or-/ and gamma . Particular emphasis is placed on meeting the stability demands of LCs without sacrificing flexibility. A general-purpose, versatile source is described that can collimate and/or tailor the bunch shape. Some interesting experiments for SLC (SLAC Linear Collider) are discussed that could provide good physics while testing such ideas for the next-generation machine.<>