IHEP, Beijing, People's Republic of China
Università degli Studi di Milano & INFN, Segrate, Italy
CEPC is a 100 km circular electron positron collider operating at 90-240 GeV center-of-mass energy of Z, W and Higgs bosons. CEPC and its successor SPPC, a 100 TeV center-of-mass super proton-proton collider, will ensure the elementary particle physics a vibrant field for decades to come. The conceptual design report (CDR) of CEPC will be completed in the end of 2017 as an important step to move the project forward. In this contribution, CEPC SRF system CDR design and challenges will be introduced, including the system layout and parameter choices, configuration at different operation energies, transient beam loading and its compensation, cavity fundamental mode (FM) and higher order mode (HOM) induced coupled bunch instabilities (CBI) and the beam feedback requirement, etc. The SRF technology R&D plan and progress as well as the SRF infrastructure and industrialization plan are discussed at last.
IHEP, Beijing, People's Republic of China
The 166.6 MHz superconducting RF cavities have been proposed for the High Energy Photon Source (HEPS), a 6 GeV kilometer-scale light source. The cavity is of quarter-wave type made of bulk niobium with β =1. Each cavity will be operated at 4 K providing 1.2 MV accelerating voltage and 145 kW of power to the electron beam. During the HEPS - Test Facility (HEPS-TF) phase, a proof-of-principle cavity of 166.6 MHz has been designed in IHEP and manufactured in Beijing. The subsequent BCP was conducted in Ningxia, while HPR, cleanroom assembly and 120 degree baking was done in IHEP. The cavity was finally vertical tested at both 4K and 2K in IHEP. The cavity Q0 at nominal gradient at 4 K was measured to be 2.4·109 with Epeak of 42 MV/m and Bpeak of 65 mT. The maximum Epeak and Bpeak reached 86MV/m and 131 mT respectively at both 4 K and 2 K, and the corresponding Q0 was measured to be 5.108 (4 K) and 3.3·109 (2 K). The residual surface resistance was measured to be 2.3 nOhm.
IHEP, Beijing, People's Republic of China
A 166.667 MHz Proof-of-Principle (PoP) superconducting RF cavity has been fabricated by IHEP for the High Energy Photon Source Test Facility (HEPS-TF) [1]. After a series of post-processing including chemical etching (BCP), high temperature heat treatment, High Pressure water Rinsing (HPR) and 120°C baking, the cavity was cold RF tested and reached Epeak=86.5 MV/m and Bpeak=132.1 mT with Q0=5.1×〖10〗8 at 4.2K. The cavity was RF tested again at 2K, and reached Epeak=85.5 MV/m and Bpeak=131.1 mT with Q0=3.3×〖10〗9.
daijin@ihep.ac.cn
IHEP, Beijing, People's Republic of China
WEYA04
IHEP, Beijing, People's Republic of China
The recent SRF R&D efforts on TEM-type cavities at IHEP have been strongly linked to two large projects: high current proton linac for ADS and High Energy Photon Source (HEPS). A CW 10 MeV proton injector and part of the 25 MeV main linac for the CADS project are developed at IHEP. 14 SRF spoke012 cavities for the injector have been commissioned with 10.6mA proton beam at 10.67MeV; while 6 SRF spoke021 cavities for the main linac have been assembled into cryomodule in Lanzhou. 166.6 MHz quarter-wave β=1 cavities were proposed for HEPS storage ring, required by the planned on-axis beam accumulation injection scheme. Each 166.6 MHz cavity will be operated at 4 K providing 1.2 MV accelerating voltage and 145 kW of power to the electron beam. A proof-of-principle cavity has been manufactured and vertical tested recently with a success. HOM damping is currently being designed. The development progress of the 6 types of spoke, HWR, QWR cavities, and their ancillaries, as well as the spoke cavity performance during beam operation, will be addressed.