Cern – european organization for nuclear research high power testing of a prototype clic structure : td 26 cc r 05 n 3

Testing of high gradient accelerating structure prototypes for the Compact Linear Collider is ongoing at CERN. High power testing of the baseline structure CLIC-G, also known as TD26CC R05, from the most recent concept design review was conducted on CERN’s second Xband test stand, Xbox 2. Several months of conditioning resulted in an ultimate unloaded gradient of 110 MV/m, the highest achieved for a structure with higher-order mode damping, with a 170ns flat-top RF pulse and operating with a breakdown rate of 2 ×10−5 breakdowns/pulse/metre. Investigations of the breakdown distribution demonstrated homogenous breakdown behaviour throughout the structure when fields were below 110 MV/m. After high power testing, a measurement of the RF parameters of the structure illustrated a significant change in the Sparameters consequential of a detuning of the cells, equating to a 1 MHz shift in the frequency. Geneva, Switzerland 19 September 2018 CLIC – Note – 1080 High Power Testing of a Prototype CLIC structure: TD26CC R05 N3 Thomas Geoffrey Lucas,∗ Matteo Volpi, Paul Giansiracusa, and Roger Paul Rassool University of Melbourne, Parkville 3010, Australia Theodoros Argyropoulos, Hikmet Bursali, Nuria Catalan-Lasheras, Alexej Grudiev, Gerard Mcmonagle, Igor Syrachev, Rolf Wegner, Ben Woolley, and Walter Wuensch European Organisation for Nuclear Research (CERN) Daniel Esperante-Pereira Instituto de Fisica Corpuscular (IFIC), Valencia, Spain Mark James Boland University of Saskatchewan, Saskatoon, Canada (Dated: 18 April 2017) Testing of high gradient accelerating structure prototypes for the Compact Linear Collider is ongoing at CERN. High power testing of the baseline structure CLIC-G* , also known as TD26CC R05, from the most recent concept design review was conducted on CERN’s second X-band test stand, Xbox 2. Several months of conditioning resulted in an ultimate unloaded gradient of 110 MV/m, the highest achieved for a structure with higher-order mode damping, with a 170 ns flat-top RF pulse and operating with a breakdown rate of 2× 10−5 breakdowns/pulse/metre. Investigations of the breakdown distribution demonstrated homogenous breakdown behaviour throughout the structure when fields were below 110 MV/m. After high power testing, a measurement of the RF parameters of the structure illustrated a significant change in the S-parameters consequential of a detuning of the cells, equating to a 1 MHz shift in the frequency.