Start-up noise in 3-D self-amplified spontaneous emission
The Self-Amplified-Spontaneous Emission (SASE) is receiving a renewed interest recently in connection with the proposal to build x-ray FEL facilities. A consistent theory of how the initial incoherent undulator radiation develops into an exponentially growing coherent signal was derived in 1-D case previously. How the theory could be extended to a 3-D case was also explained previously. In the case of the parallel electron beam, the problem was explicitly solved previously. In particular, the equivalent noise power was identified as the undulator radiation in one gain length. In this paper, we study how the result should be modified when the electrons` angular divergence is taken into account. We find that the equivalent noise power is the portion of the undulator power within the coherent phase space area, a result that should have been expected.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 412246
- Report Number(s):
- LBNL-38813; CBP-Note-180; CONF-9608133-8; ON: DE97000971
- Resource Relation:
- Conference: 18. international free electron laser conference and 3. FEL Users` workshop, Rome (Italy), 25-30 Aug 1996; Other Information: PBD: Aug 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
The Physics of Gain Mechanisms in a Self-Amplified Spontaneous Emission Free-Electron Laser
Ultrahigh harmonics generation in a FEL with a seed laser