SRF Work Packages 2 Improved Standard Cavity Fabrication

SRF Work Packages 2 Improved Standard Cavity Fabrication 7 Couplers 2. 1 Reliability analysis 7. 1 New proto-types 2. 2 Improved component design 7. 2 Titanium-nitride coating system 2. 3 EB welding 7. 3 Conditioning studies 3 Seamless Cavity Production 8 Tuners 3. 1 Seamless cavity production by spinning 8. 1 Actuators and sensor characterisation 3. 2 Seamless cavity production by hydroforming 8. 2 Control electronics 4 Thin Film Cavity Production 8. 3 Piezo-electric tuners 4. 1 Linear arc cathode 8. 4 Magneto-strictive tuner 4. 2 Planar arc cathode 9 Low Level RF 5 Surface Preparation 9. 1 Operability and Technical performance 5. 1 Electro-Polishing on single cells 9. 2 Cost and reliabilty 5. 2 Electro-Polishing on multicells 9. 3 Hardware technolgy 5. 3 Automated EP 9. 4 Software technology 5. 4 Dry ice cleaning 10 Cryostat Integration Tests 6 Material Analysis 11 Beam Diagnostics 6. 1 Squid scanning 11. 1 Emittance monitor 6. 2 Flux gate magnetometry 11. 2 Beam position monitor 6. 3 DC field emission studies of Nb samples 11. 3 HOM beam position monitor CARE Steering Committee, Paris, 5 septembre 2005 O. Napoly, CEA/Saclay 1

Accelerating RF Cavity HOM BPM • Naturally narrow band cavity : QL ≈ 104 , ~1 µs Þ single bunch, but not bunch to bunch BPM y 2 3 5 1 4 x polarization directions Centering accuracy and ‘BPM’ resolution better than 50 µm (TTF, 2004) CARE Steering Committee, Paris, 5 septembre 2005 O. Napoly, CEA/Saclay 2

1) Measurement of cavity alignment in the cryomodule • Measuring the Cavity misalignment in Cryomodule – Experiment performed last week at TTF module 4 (ACC 4) (N. Baboi, J. Frisch, L. Hendrikson, R. Paparella, et al. ) – Accelerating gradients set to zero in all 8 cavities – Reference straight trajectory across the module set by 2 BPMs on both sides of the module – Modes used : TE 1116, TE 1117, TM 1105, TM 1106 – PRELIMINARY RESULTS ( problems of reproducibilty of HOM center reconstruction w. r. t. steering ranges !! ) CARE Steering Committee, Paris, 5 septembre 2005 O. Napoly, CEA/Saclay 3

1) Monitor cavity alignment in the cryomodule PRELIMINARY RESULTS ( problems of reproducibilty of HOM center reconstruction w. r. t. steering ranges !! ) CARE Steering Committee, Paris, 5 septembre 2005 O. Napoly, CEA/Saclay 4

2) Inta-cavity Bean Position Monitor Angular scan resolution and accuracy < 50 µrad Relative position resolution ~ 4 µm (cf. M. Ross and J. Frisch). CARE Steering Committee, Paris, 5 septembre 2005 O. Napoly, CEA/Saclay 5

3) Trapped modes HOM measurements of beam excited trapped mode was successfully applied to 1. The detection of the 2. 6 GHz dipole mode (Qext = 106) 2. The qualification of superstructures It will be necessary if for the qualification of ‘Low Loss’ and ‘Reentrant’ cavity types at SMTF and STF. CARE Steering Committee, Paris, 5 septembre 2005 O. Napoly, CEA/Saclay 6

Two Challenges for HOM-BPM I) Mode to mode systematics : em. centre and polarisation Systematic center position offset ~100 µm (M. Dohlus) last 2 columns reversed !! Mode center spread ~100 µm (TTF measurements, 2004) CARE Steering Committee, Paris, 5 septembre 2005 O. Napoly, CEA/Saclay 7

Two Challenges for HOM-BPM II) Measuring the Pitch of the fondamental mode The pitch angle between the 1. 3 GHz accelerating mode and the beam trajectory (~200 µrad) is the main cause of songle bunch emittance growth in the linac. Can one measure it through the HOM couplers ? • other monopole modes of the 1 st passband through the 2 ports ? ? • systmetics of the dipole mode vs. 1. 3 GHz mode pitchs ? ? CARE Steering Committee, Paris, 5 septembre 2005 O. Napoly, CEA/Saclay 8

HOM-BPM Programme 1. Thesis of Rita Paparella (Saclay-DESY) at Orsay University (Oct. 2003 – Sept. 2006) 2. The 40 cavities of TTF will be equipped with the SLAC electronics. 3. Use for the ILC : much debatted question #36, Cost vs. Performance ? The association to CARE will allow: 1. 3 -6 months extension of Rita’s Ph. D contract (6 month delay in thesis program) 2. Participation of Claire Simon (CARE/SRF temp stall on WP 11/BPM) to the test and commissioning of the SLAC electronics at SLAC (1 month) and at DESY 3. Scientific cross-benefit CARE-ILC to the debate on HOM monitors CARE Steering Committee, Paris, 5 septembre 2005 O. Napoly, CEA/Saclay 9

HOM-BPM Programme 1. The 40 cavities of TTF will be equipped with the SLAC electronics. Project Cost and Schedule Table 1: TTF VUV-FEL HOM BPM electronics cost. Category Cost (K$ / 2. 5 K$ person-week) Engineering and Installation labor 67. 5 K$ (27 pw) Engineering and Installation cost (incl. travel) 10 K$ Production cost M/S 144 K$ Production labor cost 37. 5 K$ (15 pw) Total 181. 5 K$ production + 77. 5 K$ engineer. 20% contingency 51. 8 K $ Total 310. 8 K$ The system will be delivered before October 31, 2005. At that time, the group will work at DESY to commission the system using the TTF beam. The prototype cycle will be complete July 31, 2005. CARE Steering Committee, Paris, 5 septembre 2005 O. Napoly, CEA/Saclay 10

HOM-BPM Programme 1. The 40 cavities of TTF will be equipped with the SLAC electronics. CARE Steering Committee, Paris, 5 septembre 2005 O. Napoly, CEA/Saclay 11

New BPM mechanics Ø New design of the cavity BPM ( For the cleaning, 12 holes of diameter 5 mm have to be added) 31. 5 mm Ø Resonant modes with the new design (simulated with HFSS) New BPM F (GHz) Q R/Q at 5 mm of the center of cavity R/Q at 10 mm of the center of cavity Monopole Mode 1. 25 24 13 13 Dipole Mode 1. 72 51. 4 0. 25 1. 11 CARE Steering Committee, Paris, 5 septembre 2005 O. Napoly, CEA/Saclay 12

Cold Re-entrant BPM Linearity and Centering Accuracy New design Old design 40 µm Voltage Δ/Σ [a. u] Position of the beam (mm) CARE Steering Committee, Paris, 5 septembre 2005 Position of the beam (mm) O. Napoly, CEA/Saclay 13

SRF/WP 1/BPM Planning • Sept. 05 - Dec. 05: Fabrication of the 1 st BPM cavity (TTF room temperature). • Oct. 05 : Test and commisioning of the old type BPM in ACC 1 • Oct. 05 - Jan. 06: Fabrication of the 2 nd BPM cavity (TTF cryogenic temperature). • Jan. 06: RF tests with beam at DESY (installation of the BPM cavity + need an oscilloscope with a bandwidth >2 GHz). • Feb. 06 - Apr. 06: Validation of the RF board + Programming and validation of the digital electronics. • May 06 - June 06: Tests at DESY (2 weeks) on the cavity which is at room temperature with its electronics but without control-command interface. The tests will be done with displacement of the beam to know the noise, the dynamic range and do the calibration of this system. • Feb. 06 - Sept. 06: Installation and preparation of the cold BPM cavity. • Oct. 06: Tests of the cold cavity with the beam and electronics without the controlcommand interface. • Nov. 06 - Feb. 07: Programming of the control-command interface. • March 07: Tests of the cold cavity and its electronics. CARE Steering Committee, Paris, 5 septembre 2005 O. Napoly, CEA/Saclay 14