Wakefield and surface electromagnetic field optimisation of manifold damped accelerating structures for CLIC

A Compact Linear Collider prototype traveling-wave accelerator structure fabricated at Tsinghua University was recently high-gradient tested at the High Energy Accelerator Research Organization (KEK). This X-band structure showed good high-gradient performance of up to 100 MV=m and obtained a breakdown rate of 1.27 × 10 −8 per pulse per meter at a pulse length of 250 ns. This performance was similar to that of previous structures tested at KEK and the test facility at the European Organization for Nuclear Research (CERN), thereby validating the assembly and bonding of the fabricated structure. Phenomena related to vacuum breakdown were investigated and are discussed in the present study. Evaluation of the breakdown timing revealed a special type of breakdown occurring in the immediately succeeding pulse after a usual breakdown. These breakdowns tended to occur at the beginning of the rf pulse, whereas usual breakdowns were uniformly distributed in the rf pulse. The high-gradient test was conducted under the international collaboration research program among Tsinghua University, CERN, and KEK.

Section: Introductionmentioning

confidence: 99%

High-gradient breakdown studies of an X -band Compact Linear Collider prototype structure

Shi

Chen

et al. 2017

“…The main linear accelerator (linac) of the Compact Linear Collider (CLIC) project [16,17] uses an X-band waveguide damped structure as its baseline design [18]. The choke-mode structure [19] and the damped detuned structure [20] are also studied as alternative designs. All three structure designs use the conventional manufacturing approach and were designed and tested in recent years [21][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Design of the Compact Linear Collider main linac accelerating structure made from two halves

Zha

Grudiev

2017

Milling on two longitudinally split halves is one method to manufacture accelerating structures. This method is simple and allows one to avoid electromagnetic fields at bonding joints, making it attractive in manufacturing high-gradient accelerating structures. An X-band structure design with strong wakefield damping based on this manufacturing approach is studied in this work as an alternative design for the Compact Linear Collider (CLIC) main linac accelerating structures. The geometry of the structure is optimized to greatly reduce the surface fields, improve the efficiency, and suppress the wakefield. This structure features the baseline design of the CLIC main linac with additional advantages. This study may serve as a reference for designing other high frequency-band corrugated structures.

“…The detailed parameters are introduced in [3]. Other structures with HOM suppression are also studied as alternative designs of the CLIC main linac [4,5].…”

Section: Introductionmentioning

confidence: 99%

Design and optimization of Compact Linear Collider main linac accelerating structure

Zha

2016

The Compact Linear Collider (CLIC) main linac uses waveguide damped structure as its baseline design. The current baseline structure design written in the CLIC Conceptual Design Report is named "CLIC-G." Recent activities on the CLIC-G design including high power tests on structure prototypes and the study of machining cost assessment had raised the need of reoptimizing the structure design to minimize the machining cost and the pulse surface temperature rise. This work presents optimization of the structure geometry, high-order-mode (HOM) damping loads and the design of a HOM-free power splitter for the input coupler. Compared to the current baseline design CLIC-G, the new structure design reduced the pulse surface temperature rise, input power and manufacturing cost and achieves better suppression to the long range transverse wakefield. Cell disks and damping loads for the new structure design are also more compact than those of the CLIC-G design.