A high-brightness thermionic microwave electron gun [Thesis]

Technical Report · Fri Feb 01 00:00:00 EST 1991

DOI:https://doi.org/10.2172/7068490· OSTI ID:7068490

Borland, Michael ^[1]

---

1. Stanford Univ., CA (United States)

In a collaborative effort by SSRL, AET Associates, and Varian Associates, a high-brightness microwave electron gun using a thermionic cathode has been designed, built, tested, and installed for use with the SSRL 150 MeV linear accelerator. This thesis discusses the physics behind the design and operation of the gun and associated systems, presenting predictions and experimental tests of the gun's performance. The microwave gun concept is of increasing interest due to its promise of providing higher-current, lower-emittance electron beams than possible from conventional, DC gun technology. In a DC guns, accelerating gradients are less than 8 MV/m, while those in a microwave gun can exceed 100 MV/m, providing much more rapid initial acceleration, thereby reducing the deleterious effects of space-charge. Microwave guns produce higher momentum beams than DC guns, thus lessening space-charge effects during subsequent beam transport. Typical DC guns produce kinetic energies of 80--400 KeV, compared to 2--3 MeV for the SSRL microwave gun. State-of-the-art'' microwave gun designs employ laser-driven photocathodes, providing excellent performance but with greater complexity and monetary costs. A thermionic microwave gun with a magnetic bunching system is comparable in cost and complexity to a conventional system, but provides performance that is orders of magnitude better. Simulations of the SSRL microwave gun predict a normalized RMS emittance at the gun exist of < 10 {pi} {center dot} m{sub e}c {center dot} {mu}m for a beam consisting of approximately 50% of the particles emitted from the gun, and having a momentum spread {plus minus}10%. These emittances are for up to 5 {times} 10{sup 9}e{sup {minus}} per bunch. Chromatic aberrations in the transport line between the gun and linear accelerator increase this to typically < 30 {pi} {center dot} m{sub e} {center dot} {mu}m.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00515
• OSTI ID: 7068490
• Report Number(s): SLAC-402; SLAC-R-402; ON: DE92018587
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ELECTRON GUNS
DESIGN
BEAM BUNCHING
BEAM DYNAMICS
BEAM EMITTANCE
BEAM OPTICS
COMPUTERIZED SIMULATION
ELECTRON BEAMS
LASERS
LINEAR ACCELERATORS
MAGNETIC FIELDS
MATRICES
MICROWAVE EQUIPMENT
PHOTOCATHODES
TESTING
ACCELERATORS
BEAMS
CATHODES
ELECTRODES
ELECTRONIC EQUIPMENT
EQUIPMENT
LEPTON BEAMS
PARTICLE BEAMS
SIMULATION
430301* - Particle Accelerators- Ion Sources