SRF Section Cuvée 2014

SRF section LHC – SRF (Machine + Spares) HIE-ISOLDE (Cavities + Modules + PM) HL-LHC (CRAB) – SPS testing SPL – High Gradient Research FCC R&D – Cryolab SRF infrastructure & CRISP Collaborations & TTC

RF-SRF 2015

Snapshot of Projects Work SPL cavity 001: Alick&team trying to break the 3 MV/m barrier – now seems to perform LHC SRF system: Pierre&co. re-commissioning for start-up – mostly ok. Cavity production proceeding. Spares recovery launched. HIE-ISOLDE: QS05 for cold testing. SM18 module assembly team around Mathieu working hard. Walter preparing for yet another review. Crab: After intense testing and workshop now time for reflection on programme Snapshot of Projects Work K.M. Schirm on behalf of BE-RF-SRF RF Annual – Dec. 12th; 2014

LS1 SRF Module Swap

LHC UNIT19 K.M. Schirm on behalf of BE-RF-SRF

HIE-ISOLDE first set of 5 (+1) Nb/Cu cavities Phases of HIE ISOLDE cavity processing at CERN, LLRF controllers, fundamental coupler, tuning system, test cryostat, performance curves of the first 6 series cavities

Cryo module assembly View of the assembly area with the two ISO5 clean rooms, lifting frame, particle counting, insertion of thermal shield into vacuum vessel

Crab crossing 4 Rod Crab cavities IR

Post HL-LHC Review Conclusions (May 2014) SPS Test is of Crab cavity Prototypes is critical at least one cryomodule before LS2, possibly two, of different cavity type. additional testing in LHC P4 kept as a possibility but not in the baseline Crab Cavity prototypes to be tested for the SPS Concentrate on two designs for testing in the SPS Double Quarter Wave design RF Dipole design SPS Crab cavity Installation 2 cavities of the same type in a common cryomodule Cryomodules must be easily exchangable Exchange within an SPS Christmas stop

SRF Crab Cavity: Cold testing

RFD Test Results The RFD cavity was tested at Jlab and was able to achieve a voltage far in excess of the specification (acc. phys please do not get excited and increase the required voltage). The cavity has now been re-tested at CERN and achieved similar results. TEST I Q0 = 1.25×1010 @ 2 K (Rs=9.5 nΩ) TEST II Q0 = 4.0×109 @ 2 K (Rs=34 nΩ) Limited by RF Power Quench

DQW test results The DQW was tested at BNL and achieved above the design spec. Q was reduced by the beampipe flanges, these have now been coated with Nb and retested at CERN.

SRF SPL Activities

Teamwork around SPL cold testing

Cryolab Activities Cavity Diagnostic Developments with OSTs S. Aull, T. Junginger, B. Peters Cryolab Activities Cavity Diagnostic Developments with OSTs Fundamental SRF studies using the Quadrupole Resonator New Coating Technologies: HIPIMS on 1.3 GHz cavities Collaboration with TE-VSC S. Calatroni and G. Terenziani Master Thesis B. Peters (Univ. Karlsruhe) with Co-Supervisor T. Koettig (TE-CRG) PhD Thesis S. Aull (Univ. Siegen) Supervisor: S. Doebert Thanks to the cryolab team for their continued support in 2014!

SRF Research in the Cryolab T. Junginger S. Aull SRF Research in the Cryolab 1.3 GHz HIPIMS Cavities Sample Testing with the Quadrupole Resonator High precision tests of HIPIMS cavities Understanding, controlling and minimizing field dependent losses of Nb/Cu cavities Effects studied: Low temperature baking Thermal cycling Thermal boundary resistance 140 Surface Resistance [nΩ] 20 40 RF Magnetic Field [mT] Measurement of the cavity’s inner surface temperature RRR does not seem to be the cause of the Q-Slope of Nb Films. Simultaneous measurement of RS and pressure of helium gas introduced in the cavity as a function of Eacc show that global warming is not the cause for the field dependent surface resistance of Nb/Cu cavities Cooling Rate [mK/s] Thermal cycling has a strong impact on the RS.

A. Benoit P. Horn T. Junginger B. Peters Quench detection OST quench detection system implemented for SM18 cavity cold tests New Software to locate quenches for any cavity geometry including a new more reliable triangulation algorithm For enhanced OST resolution and to obtain more information like impact angle from the signals: Fundamental studies to understand the 3 dimensional heat transport in superfluid helium at high heat flux (Master thesis B. Peters in collaboration with TE-CRG)

Closing Remarks: SRF section continues growing 2015 will be challenging (again!!!) Giovanna Vandoni 01/2015 Priority management ! Sorry to all the people (activities) not specifically mentioned here