Spoke test in vertical cryostat IPNO-UU Meeting on spoke test program, 2 nd -3 st October 2013 IPNO Team

 Typical measurements in vertical cryostat Qo = f(Eacc) curve Qo at low field Qo at nominal Eacc Max achievable gradient (what is the cavity limit) Check for MP barriers, assess how difficult/easy it is to process Characterized field emission activity (onset, levels, …) Qt calibration (and also Qi but far from nominal case) Lorentz detuning coefficient (“not nominal” case) Sensitivity to helium pressure fluctuation Kp (also in “not nominal” case) Purpose of VC tests

 What is tested ? Cavity intrinsic ability and performances to accelerate Cavity mechanical behavior Cavity preparation efficiency Chemical etching procedure Clean room preparation and assembly procedure Cavity “special” treatment efficiency Cavity baking Cavity heat treatment (H degazing) – 100 K effect Venting procedure Points #1 and #3 should be tested as soon as possible and reached at least on one prototype the nominal Qo and Eacc. Purpose of VC tests

 Overall WP4 planning WP4: in blue & black: official ESS planning in Primavera in red: desired new dates (earlier dates, to release pressure on series testing) WP11: Desired schedule (but very tight for the prototype valve box) – Details non official – But should be compatible with the official ESS en date for linac cryo ancillaries installation ends in dec. 2017

 Milestones & Go/No go for tendering Several test results are validation of components ability to perform as required by ESS and thus are mandatory before launching series fabrication: Cavity test in vertical cryostat (achieve 9MV/m and nominal Qo) Required prior tendering for niobium production for series (March 2015) i.e. one successful test to be achieved in February 2015 at the latest Cavity with coupler test in HNOOS (coupling successful, CTS, nominal gradient) The test requires around 100 kW of RF power Required prior tendering for cavity series production (Feb. 2016) i.e. one successful test to be achieved in Dec 2015 at the latest Prototype cryomodule test (validate cryo, assembly, overall results) Required prior tendering for series spoke cryomodule production (July 2016) i.e. one successful test to be achieved in June 2016 at the latest

 Go/ No go #1 : Successful test of a cavity in vertical cryostat Milestones & Go/No go for tendering Go/ No go #2: Successful test of a cavity+coupler in HNOOS Go/ No go #3: Successful test of the spoke prototype cryomodule