IHEP GHz 9-cell Cavity R&D Status and Plan The Third IHEP-KEK 1.3GHz SC Technology Collaboration Meeting Dec. 7-8, 2010, IHEP, Beijing GAO Jie, ZHAO Tongxian, ZHAI Jiyuan, LI Zhongquan, LI Dazhang, LIU Zhenchao Institute of High Energy Physics, Chinese Academy of Sciences CHEN Jinzhe, QIAO Jianqiang Beijing Hejieli Science and Technology Development Co. Ltd. YUAN Hong, YU Huai, WANG Jinxue Beijing Institute of Aviation Materials

OUTLINE Backgound of the IHEP 9-cell cavity IHEP-02 R&D goal and schedule IHEP-02 Fabrication Procedure HOM coupler

BACKGROUND  IHEP-01: Low-Loss Type 9-cell Cavity with Bare Tubes (VT)  IHEP-02: Low-Loss Type 9-cell Cavity with Full End Groups (VT&HT) IHEP-01 First Vertical Test Result Of IHEP-01 20MV/m

IHEP-02 R&D GOAL, SCHEDULE IHEP-02 with full end groups for the horizontal test Achieve the requirement of ILC  25-35MV/m for the vertical test  MV/m for the horizontal test IHEP Fabrication IHEP Surface treatment IHEP Vertical test Other Lab weld helium vessel IHEP assemble and HT IHEP

OUTLINE Backgound of the IHEP 9-cell cavity IHEP-02 R&D goal and schedule IHEP-02 Fabrication Procedure HOM coupler

Large Grain Niobium Sheets The cavity material disks from Ningxia OTIC (Nov., 2008) inspection, CP, annealing ultrasonic and eddy current scanning tests mechanical behavior sample test at room temp. and 4K RRR measurement We do that when we made the IHEP-01

Nb sheets thickness measurement The problem ： uneven thickness like the above sketch map(1) will lead to large crack, the Uniform thickness maybe good, but we think uneven thickness like the good cketch map(2) may be better. 1: NOT GOOD 2: GOOD

IHEP-02 Progress O C, 3Hours Heating and cooling speed ： 300 O C/H 4: After annealing, we deep drawing the half cell again. 1: deep drawing 2: trimming After trimming, Waiting for measurement Some half cells 3: Annealing after first trimming

Comparing of the twice deep drawing 37# # # # # # # # #0.10 4# Half cell No. After the first deep drawing After the second deep drawing Standard deviation

IHEP-02 Progress The half cells Frequency measurement of the half cell length, iris and equator diameter measurement

The measurement data Cell No. Freq.Q MHz Cell No. Average / mm Standard deviation / mm Cell No. Averag e / mm Standard deviation / mm Iris wall thickness Iris diameterFrequency of the half cell

IHEP-02 Progress  Equator roundness reshaping  20 μm chemical polishing of half cells, ultrasonic cleaning, rinsing, 3 μm chemical polishing at iris area, Rinsing,  EBW. New Fixtures for cell equator roundness equator roundness reshaping

equator roundness reshaping result 37# # # # # # # # # #0.04 No. Before reshaping after reshaping Standard deviation

IHEP-02 Progress Dumbell without stiffening ringDumbell with stiffening ring

stiffening rings forming

OUTLINE Backgound of the IHEP 9-cell cavity IHEP-02 R&D goal and schedule IHEP-02 Fabrication Procedure HOM coupler

IHEP-01 Mode; Freq. --- R/Q Boundary conditions: Electric-Electric & Magnetic-Magnetic

IHEP 01 Q E CALCULATION TM010 ： 1.3GHz ， Q e 2.88e+010 TE111 ： Freq GHz ， GHz Q e : 4.24e+004 ， 7.85e+004 TM110 ： 1.87GHz ， Q e 1.37e+004 TM011 ： 2.16GHz Q e ： 2.97e+004 CST Model Lines per wavelength55 Lower mesh limit15 Mesh line ratio limit10 LL cavity with Tesla HOM coupler

HOM coupler material Nb StickRRR300 D60 ， L500 5 couplers housing Nb sheetRRR300200×150×8.86 Inner conductors 5 Tesla HOM couplers

IHEP-02 next plan HOM coupler fabrication will be speed up. End groups fabrication Cavity Welding IHEP-02 will be finished at early 2011

Summary The multi-cell cavity is one of the key components for 1.3 GHz SRF technology R&D of IHEP. We have developed effective methods, procedures, tools and facilities to fabricate and tune the 9-cell cavity. The IHEP-01 finished fabrication and EBW, surface treated at IHEP and tested at KEK STF in July MV/m. It will be test at kek again in early The IHEP-02 will finish in early 2011, surface treated at IHEP and test in middle 2011.

Thanks for your attention