High Power Operations of LEDA

The LEDA RFQ, a 350-MHz continuous wave (CW) radio-frequency quadrupole (RFQ), successfully accelerated a 100-mA CW proton beam from 75 keV to 6.7 MeV. We have accumulated 111 hr of beam on time with at least 90 mA of CW output beam current. The 8-m-long RFQ accelerates a dc, 75-keV, ~106-mA H+ beam from the LEDA injector with ~94% transmission. When operating the RFQ at the RF power level for which it was designed, the peak electrical field on the vane tips is 33 MV/m. However, to maintain the high transmission quoted above with the CW beam, it was necessary to operate the RFQ with field levels ~10% higher than design. The RFQ dissipates 1.5 MW of RF power when operating with this field. Three klystrons provide the 2.2 MW of RF power required by the RFQ to accelerate the 100-mA beam. The beam power is 670 kW. Some of the challenges that were met in accelerating a 100-mA CW proton beam to 6.7 MeV, will be discussed.

[1]  A. Regan,et al.  Design, operation, and test results of 350 MHz LEDA RF system , 1998 .

[2]  E. A. Meyer,et al.  Status report on a dc 130 mA, 75 keV proton injector (invited) , 1997 .

[3]  P. McGehee,et al.  Commissioning of the Low Energy Demonstration Accelerator (LEDA) radiofrequency quadrupole (RFQ) , 1999, Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366).

[4]  G. Domer,et al.  Resonance Control Cooling System for the APT/LEDA RFQ , 1998 .

[5]  Lloyd M. Young,et al.  CW RFQ fabrication and engineering , 1998 .

[6]  L. Young.  An 8-meter-long coupled cavity RFQ linac , 1994 .

[7]  K. Crandall,et al.  Beam Halo in Proton Linac Beams , 2000 .

[8]  L. Young.  Simulations of the LEDA RFQ 6.7-MeV accelerator , 1997, Proceedings of the 1997 Particle Accelerator Conference (Cat. No.97CH36167).

[10]  W. D. Kilpatrick,et al.  Criterion for Vacuum Sparking Designed to Include Both rf and dc , 1957 .

[11]  Frank L. Krawczyk,et al.  A New RF Structure for Intermediate-Velocity Particles , 1994 .

[12]  P. McGehee,et al.  UPDATE ON THE COMMISSIONING OF THE LOW-ENERGY DEMONSTRATION ACCELERATOR (LEDA) RADIO-FREQUENCY QUADRUPOLE (RFQ) , 2000 .

[13]  P. Balleyguier,et al.  LEDA LLRF control system characterization , 1998 .

[14]  M. Jong.  Background Ion Trapping in RFQs , 1984 .

[15]  P. McGehee,et al.  Low-Energy Demonstration Accelerator (leda) Radio-Frequency Quadrupole (rfq) Results , 2000 .

[16]  J. D. Schneider,et al.  Operation of the Low-Energy Demonstration Accelerator: the proton injector for APT , 1999, Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366).

[17]  N. Diserens.  Progress in the Development of a 3d Finite Element Computer Program to Calculate Space and Image Charge Effects in RF Quadrupoles , 1985, IEEE Transactions on Nuclear Science.

[18]  K. Johnson,et al.  MEASUREMENT OF RF ACCELERATOR CAVITY FIELD LEVELS AT HIGH POWER FROM X-RAY EMISSIONS· , 1990 .

[19]  L. Young.  SIMULATIONS OF THE LEDA LEBT WITH H + , H2 + , AND E - PARTICLES* , 1998 .

[20]  J. D. Schneider,et al.  DETERMINING PHASE-SPACE PROPERTIES OF THE LEDA RFQ OUTPUT BEAM , 2000 .

[21]  L. M. Young,et al.  Coupled radio-frequency quadrupoles as compensated structures , 1990 .