WG-1 Session Cavity Performance Cryomodule Performance Data (near future/ Large scale) Low Beta performance

WG1-Session1 Cavity Performance Camille Ginsburg (FNAL), John Mammosser (JLAB)

Five talks were presented covering recent cavity vertical test RF performance from: KEK STF-2 cavities (Yamamoto) JLab 12GeV cavities (Reece) DESY XFEL cavities (Reschke) FNAL ILC/ProjectX cavities (Ginsburg/Ozelis) FNAL/ANL and KEK facilities, processes and procedures are a fully functional for state of the art gradients R&D is well underway for further developments

What can we take for the data presented: Gradients greater then 25MV/m were easily and consistently met from all labs (KEK, DESY, FNAL, JLAB) Field emission is present in most data but not always the limit Still a few low gradient FE onsets (accidents) in all data Example FNAL 38 9-cell tests 2010 (FNAL and some JLab) Radiation detector location and shielding different at each lab but do the data shows similar spread?

Additionally: Many vertical cavity tests being performed A very good opportunity to capture data and gain understanding Good diagnostic methods being applied, example is KEK (optical & thermal) Need to continue to track FE, still present in most tests Field emission is usually recovered by HPR but not always (statistics are needed to further understand limits)? Small number of incidents still occur which affect cavity performance

Questions to the SRF community: Are we capturing the enough data to understand limits? Are the data compatible / comparable? What should be changed?

WG1-Session2 Low Beta Cavity Performance Paolo Pierini (INFN), John Mammosser (JLAB)

Four talks were presented covering recent low beta cavity activities from: ESS (R&D Plans CEA) G. Devanz IAP (SC activities) M. Busch Project-X (Cavities/tuner FNAL) L. Ristori ESS (RF simulations at RHUL) S. Molloy

ESS (R&D Plans CEA) G. Devanz Double spoke resonators Frequency = 352.21 MHz Beta = 0.53 Challenges: • High gradients ( 8 MV/m ) • High peak power couplers (~ 400 kW nominal) • Pulsed operation • Series production of spoke cavities (real 3D geometry and performance reproducibility) • Open questions : HOM Operation T° (2K or 4K) Cryomodule type …

Main contributors for prototypes CNRS/IN2P3/IPN Orsay (France): cavities (2 prototypes), couplers ( 2proto types), tuners, cryomodule, preparation and test facility, WP coordination ESS BILBAO/TEKNIKER (Spain): cavities, tuners, engineering design (mechanical, RF) JLAB (USA) : Discussion in progress for a plug- compatible cavity design and prototype, independent cryomodule design

ESS design and prototyping activities at CEA-Saclay High beta (0.86) 704 MHz 5-cell cavities, 2 prototypes HOM couplers 1 MW power couplers, 2 prototypes Magnetic shielding Combined fast/slow tuner Design update (2011-2012) RF Conceptual design of the cavity 6 high beta (0.86) 704 MHz 5-cell cavities with HOM couplers, tuner, magnetic shielding, power coupler Fabrication, preparation conditioning and test of all elements P2B (2013-216)

Collaboration on ESS elliptical cavities CEA-Saclay : high beta cavities, power couplers, tuners ESS-AB : cryomodule and cryogenics Lund-U : medium beta cavities Rostock : HOM (RF WP8) RHUL : HOM, complex RF and multipacting simulations (RF WP8) CERN : 704 MHz test area, 4-cavity cryomodule test (beta=1 cavities) Upsala : Fully equiped test stand with horizontal cryostat Jlab and DESY : On going discussions for cryomodule conceptual design comparisons

SC activities IAP Frankfurt Prototyping RF Qualification 325MHz CH cavity prototyping and RF testing

CH Cavity Vertical Test Results

Low Beta cavities and tuner development FNAL 325 MHz SSR1 Design Cavity designed and modeled RF model + Mechanical Design Prototypes were fabricated industry Tuning and trimming Processing Vertical RF testing Helium jacket completed Horizontal RF testing

SSR1 RF Test Results: Vertical test results Horizontal Test – excellent results Tuner Developed

ESS Cavity RF Modeling (Royal Holloway):

Development of a simplified model:

Summary of WG session: Low Beta cavity projects are active and developing in all regions Cavity design Modeling Fabrication Testing (Good Performance) Horizontal and vertical