A 3 Ghz photoelectron gun for high beam intensity

Conference · Sun Dec 31 00:00:00 EST 1995

DOI:https://doi.org/10.1016/0168-9002(95)01369-5· OSTI ID:238756

Bossart, R; Braun, H; Dehler, M ^[1]

---

1. European Organization for Nuclear Research (CERN), Geneva (Switzerland); and others

The CLIC Test Facility (CTF) for new accelerator structures of the proposed Compact Linear Collider (CLIC) is to be equipped with a new RF gun containing a laser driven photocathode. The new 3 GHz gun with photocathode shall produce a bunch train of 48 electron bunches of 25 nC charge each with a bunch length of 8 - 15 ps fwhm. The new RF gun consists of 2{1/2} cells and accelerates the beam to an energy of 7 MeV with a peak field gradient Ez = 100 MV/m. The strong space charge forces at low beam energy caused by the high charge density of the electron bunches must be contained by radial and longitudinal RF focusing in the RF gun. Radial RF focusing is applied by a conical backplane around the photocathode in the first cell where the electrons have a low energy. Longitudinal RF focusing is obtained by varying the length of each of the three cells of the gun. The total electric charge of the bunch train exceeds 1{mu}C and causes strong beam loading to the RF structures so that the stored energy is reduced to half of the unloaded RF energy. The RF gun under construction is being optimized by MAFIA beam simulations for an injector assembly comprising a second accelerating RF structure of 4 cells and an intermediate solenoid magnet correcting the beam divergence of the 2{1/2} cell gun. The scheme with two accelerating RF sections will provide a linear energy increase along the bunch suitable for further compression of the bunch length in a magnetic chicane.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States)
• OSTI ID: 238756
• Report Number(s): BNL-61982-Absts.; CONF-9508156-Absts.; ON: DE96002729; TRN: 96:013245
• Resource Relation: Journal Volume: 375; Journal Issue: 1-3; Conference: 17. international free electron laser conference, New York, NY (United States), 21-25 Aug 1995; Other Information: PBD: [1995]; Related Information: Is Part Of 17th international free electron laser conference and 2nd international FEL users` workshop. Program and abstracts; PB: 300 p.
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ELECTRON GUNS
DESIGN
LINEAR COLLIDERS
PHOTOCATHODES
RF SYSTEMS
SPACE CHARGE