Paper | Title | Page |
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TUPMA038 | Start-up of an FEL Oscillator from Shot Noise | 163 |
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In free-electron laser (FEL) oscillators, as in self-amplified spontaneous emission (SASE) FELs, the build-up of intra-cavity power starts from shot noise resulting from the discreteness of charge in the electron bunch. It is important to do the start-up analysis for the build-up of intracavity power in order to fix the macropulse width from the electron accelerator such that the system reaches saturation. In this paper, we show that one can use the time-dependent oscillator code GINGER [1] to perform this anlysis. we present results of this analysis for the parameters of the Compact Ultrafast TErahertz FEL (CUTE-FEL) [2] being built at RRCAT.
1. W. Fawley, 'A user Manual for GINGER and Its Post-Processor XPLOTGIN}},LBNL-49625-Rev. I' ed., Lawrence Berkley National Laboratory (2004).2. S. Krishnagopal et al., Proceedings of FEL conference (2006) 496. |
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WEPMA111 | Mechanical Engineering Challenges in the Development of the FEL at RRCAT | 479 |
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The Compact Ultrafast TErahertz Free-Electron Laser (CUTE-FEL) is being developed by BP&FEL Laboratory, RRCAT, which is designed to lase around 80 mm. Sub-systems like S-band high gradient accelerating structures, pre-buncher, buncher, pure permanent undulator etc. have already been developed and others are in advanced stage of fabrication/commissioning. In this paper we present the design, fabrication, measurements and status of various prototype developments of structures. | ||
WEPMA112 | Thermal Simulations of a Photocathode R. F. Gun | 482 |
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We are developing a photocathode linac, which uses a 2856 MHz r.f. gun, with a copper cathode driven by a 102 MHz, 266 nm laser at inclined incidence. The laser photocathode r.f. gun is a 1.6 cell BNL/SLAC/UCLA type III r.f. gun. In this paper we present the dynamic thermal cooling simulations to calculate the structural deformations and consequent frequency drift of the gun. We have done a complete r.f.-thermal-structural-r.f finite-element analysis (FEA) of the gun in that order, using ANSYS/MULTIPHYSICS. We find that with the present coolant channel design the gun can operate at up to 2 Hz without any significant change in resonant frequency and field balance. |