LCLS Gun Solenoid Design Considerations
نویسنده
چکیده
The LCLS photocathode rf gun requires a solenoid immediately downstream for proper emittance compensation. Such a gun and solenoid have been operational at the SSRL Gun Test Facility (GTF) for over eight years. Based on magnetic measurements and operational experience with the GTF gun solenoid multiple modifications are suggested for the LCLS gun solenoid. The modifications include adding dipole and quadrupole correctors inside the solenoid, increasing the bore to accommodate the correctors, decreasing the mirror plate thickness to allow the solenoid to move closer to the cathode, cutouts in the mirror plate to allow greater optical clearance with grazing incidence cathode illumination, utilizing pancake coil mirror images to compensate the first and second integrals of the transverse fields and incorporating a bipolar power supply to allow for proper magnet standardization and quick polarity changes. This paper describes all these modifications plus the magnetic measurements and operational experience leading to the suggested modifications.
منابع مشابه
Tolerances for magnetic fields in the Gun-To-Linac region of the LCLS Injector
In this technical note, we review the computations which led to the tolerances on residual quadrupole field terms in the magnets of the Gun-To-Linac region of the LCLS Injector. If the dipole terms can be cancelled by appropriately steering the beam, the quadrupole term damages the focusing scheme and generates an asymmetry in the horizontal and vertical emittances. Quadrupole terms deteriorate...
متن کاملPhotocathode rf gun emittance measurements using variable length laser pulses
The Gun Test Facility (GTF) at the Stanford Linear Accelerator Center (SLAC) was created to develop an appropriate injector for the proposed Linac Coherent Light Source (LCLS) at SLAC. The LCLS design requires the injector to produce a beam with at least 1 nC of charge in a 10 ps or shorter pulse with no greater than 1 -mrad normalized rms emittance. The first photoinjector under study at the G...
متن کاملTransverse Emittance Measurements from a Photocathode RF Gun with Variable Laser Pulse Length
The Gun Test Facility (GTF) at SSRL was started in 1996 to develop an appropriate injector for the proposed Linac Coherent Light Source (LCLS) at SLAC. The LCLS design requires the injector to produce a beam with at least 1 nC of charge in a 10 ps or shorter pulse with no greater than 1 mm-mrad normalized rms emittance. The photoinjector at the GTF is 1.6 cell S-band symmetrized gun and emittan...
متن کاملPhotoinjector design for the LCLs
The design of the Linac Coherent Light Source assumes that a low-emittance, 1 nC, 10 ps beam will be available for injection into the 15GeV linac. The proposed rf photocathode injector that will meet this requirement is based on a 1.6cell S-band rf gun equipped with an emittance-compensating solenoid. The booster accelerator with a gradient of 25MV/m is positioned at the beam waist coinciding w...
متن کاملThermal emittance - Solenoid Speci cations
To de ne the location of YAG1, simulations of solenoid scans were done using PARMELA used as an optical properties tracker. Analytical computations are dif cult to perform when one wants to take into account the focusing properties of the RF cavity with that of the solenoid on a realistic beam. The required range of solenoid currents and the screen position of YAG1 are justi ed. The thermal emi...
متن کامل