IHEP ILC Cavity Status Jiyuan Zhai (IHEP) on behalf of the IHEP ILC SRF Team LCC-ILC Cavity Meeting March 4, 2015

ILC Test Cryomodule Second LN2 cool down test in Feb., with new cryogenic connections (welding instead of many seals) Isolation vacuum improved: 1E-1 Pa => 6E-6 Pa, with larger TMP Cavity vacuum improved: 4E-5 Pa => 8E-8 Pa, with large ion pump and NEG in beam tube Confirm 2K line cold leak inside cryomodule. Plan to disassemble the module, find and repair the leak (indium/copper seals? TIG weld? helium vessel?), reassemble and 80K cool down test again in mid 2015 Cavity further expanded 0.7 mm (will press the cavity after disassembly and add mechanical stopper on the tuner)

Mechanical Stopper for Cavity Expansion (KEK STF) Several tuner types can both press and stretch cavity (Saclay2 tuner, CEBAF upgrade)

HOM1 Cross Talk with Input Coupler Qt: 7E11 (VT) s21 (input coupler in) Pickup out: - 55 dB HOM1 out: - 42 dB HOM2 out: - 54 dB

Cavity R&D TESLA-like 9-cell Cavity (IHEP-03, FG) IHEP-KEK collaboration; EBW completed in end 2014 Tumbling at IHEP in March-April, process and test at KEK in May-June TESLA 9-cell Cavity (HER-01, FG) with full end groups, plan to complete in end 2015 A spoke024 cavity welded by IHEP EBW machine in 2014, => 4+4 spoke High Q study by nitrogen doping 1.3 GHz single cell using IHEP’s new furnace

New Cryogenic Plant in Operation Tested in Jan. 2015 Refrigeration: 1020 W @ 4.5 K Liquefaction: 302 L/h Mixed mode: 352 W + 200 L/h Total pumping: 8000 m3/h @ 3100 Pa (200 W @ 2 K) System now in operation for China ADS injector TCM1 (two spoke012 cavities with solenoids, 10 mA CW), and later for ADS cryomodules (14 spoke cavities), ILC test cryomodule, FEL-ERL test facility cryomodules, and vertical test stand)

New Vertical Test Stand Inner diameter: 850 mm Magnetic shield inside dewar Effective diameter: 800 mm Various cavities: 1.3 GHz - 325 MHz Start closed-loop 2K vertical test in mid 2015

New RF Power Source 1.3 GHz 5 MW (1.6 ms pulsed) klystron Marx modulator Both to be delivered in end March 2015 Waveguides, circulator, loads etc. (funded soon)