CEPC/SppC and FCC Collaboration J. Gao On behalf of CEPC+SppC Group IHEP, CAS, China Pre-FCC ICB Meeting Sept. 9-10, 2014
Dec 19, 2015
CEPC/SppC and FCC Collaboration
J. Gao
On behalf of CEPC+SppC Group
IHEP, CAS, China
Pre-FCC ICB Meeting Sept. 9-10, 2014
Lepton and Hadron Colliders’ History and China Accelerator based High Energy
Physics Development in the Future
2
BEPC II
LC
BEPC
History of BEPC and BEPC II
CEPC+SppCCEPC: Ecm=240GeV e+e- Circular ColliderSppC: Ecm=50-100TeV pp Collider
HIEPAF: High Intensity Electron Positron Accelerator Facility
Old picture!
CEPC+SppC will be constructed with international collaboration and participation
Strategy on Future High Energy Colliders of China1) On “The 464th Fragrant Hill Meeting”, Chinese High Energy Physics Community
arrived at the following consensus: a) China supports ILC and will participate to ILC construction with in-kind contributions and requests R&D fund from government b) After the discovery of Higgs, as next collider after BEPCII in China, a
circular e+e- Higgs factory ( CEPC ) and a Super proton- proton Collier (SppC) afterwards in the same tunnel is an important
option and historical opportunity.2) During the meeting of Chinese High Energy Physics Association on “China High
Energy Physics based on Particle Accelerators”, Feb. 28, 2014, it was concluded that:“Circular e+e- Circular Higgs Factory(CEPC) +Super pp Collider (SppC) is the first choice for China’s future high energy physics accelerator.
• It is considered that CEPC (250GeV upper limit) is supplementary to ILC in terms of its energy range down to W and Z boson and to the number of detectors from both machines
• International collaboration and participation are necessary
Preliminary Conceptual Design Report of CEPC-SppC
Writing assigned for Pre-CDR
4 CEPC - accelerator physics
4.1 Main parameters Guo Yuanyuan, Geng Huiping, Wang Dou, Xiao Ming, Gao Jie
4.2 LatticeGeng Huiping, Wang Dou, Guo Yuanyuan, Wang Na, WangYiwei, Xiao Ming, Peng Yuemei, Bai Sha, Su Feng, Xu Gang, Duan Zhe, Gao Jie
4.3 IR and MDIWang Dou, Geng Huiping, Wang Yiwei, Bai Sha, , Gao Jie
4.4 Beam instability Wang Na, Wang Yiwei
4.5 Beam-beam effectsZhang Yuan, Guo Yuanyuan, Wang Dou, Xiao Ming, Gao Jie
4.6 Synchrotron radiation Ma Zhongjian, Geng Huiping4.7 Injection and beam dump Cui Xiaohao, Su Feng, Xu Gang4.8 Background Yue Teng4.9 Polarization Duan Zhe
Visitors from other labs in the world participate the Pre-CDR joint works
CEPC Layout
LTB : Linac to Booster
BTC : Booster to Collider Ring
BTC
IP1
IP2
e+ e-
e+ e- Linac (240m)
LTB
CEPC Collider Ring(50Km)
Booster(50Km)
BTC
SppC Layout
Medium Energy Booster(4.5Km)
Low Energy Booster(0.4Km)
IP4 IP3
SppC Collider Ring(50Km)
Proton Linac(100m)
High Energy Booster(7.2Km)
CEPC/SppC Layout
LTB : Linac to Booster
BTC : Booster to Collider Ring
BTC
IP1
IP2
e+ e-
e+ e- Linac (240m)
LTB
CEPC Collider Ring(50Km)
Booster(50Km)
BTCMedium Energy Booster(4.5Km)
Low Energy Booster(0.4Km)
IP4 IP3
SppC Collider Ring(50Km)
Proton Linac(100m)
High Energy Booster(7.2Km)
Possible site (example)• 300 km from Beijing• 3 h by car• 1 h by train
9/45
BeijingQinhuangdao
Tianjing
Beidaihe
Parameter Unit Value Parameter Unit ValueBeam energy [E] GeV 120 Circumference [C] km 53.6Number of IP[NIP] 2 SR loss/turn [U0] GeV 3Bunch number/beam[nB] 50 Bunch population [Ne] 3.71E+11SR power/beam [P] MW 50 Beam current [I] mA 16.6
Bending radius [] m 6094momentum compaction factor [p]
4.15E-05
Revolution period [T0] s 1.79E-04 Revolution frequency [f0] Hz 5991.66
emittance (x/y) nm 6.79/0.021
IP(x/y) mm 800/1.2
Transverse size (x/y) m 73.7/0.16 x,y/IP 0.1/0.074Beam length SR [s.SR] mm 2.35 Beam length total [s.tot] mm 2.66Lifetime due to Beamstrahlung min 80
lifetime due to radiative Bhabha scattering [L]
min 56
RF voltage [Vrf] GV 6.87 RF frequency [frf] MHz 650
Harmonic number [h] 116244Synchrotron oscillation tune [s]
0.199
Energy acceptance RF [h] % 5.56 Damping partition number
[J] 2
Energy spread SR [.SR] % 0.13 Energy spread BS [.BS] % 0.07 Energy spread total [.tot]
% 0.15 n 0.22
Transverse damping time [nx]
turns 81Longitudinal damping time [n]
turns 40
Hourglass factor Fh 0.679 Luminosity /IP[L] cm-2s-1 1.8E+34
Main parameters for CEPC
Parameter Value Unit
Circumference 52 km
Beam energy 35 TeV
Dipole field 20 T
Injection energy 2.1 TeV
Number of IPs 2 (4)
Peak luminosity per IP 1.2E+35 cm-2s-1
Beta function at collision 0.75 m
Circulating beam current 1.0 A
Max beam-beam tune shift per IP 0.006
Bunch separation 25 ns
Bunch population 2.0E+11
SR heat load @arc dipole (per aperture) 56 W/m
SppC main parameters
Beam-beam tune shift limit analytical calculations
max
2845
6p
IP
r
f x RN
dtt
xfx
0
2
)2
exp(2
21)(
IPpIP NrRxf
Nxf
x
6
2845)(4)(4 2
max
2
03656.2x
0417.0)( xf
0064.0max
For lepton collider:
For hadron collider:
where SppC (actual parameter list)
FCC (pp) 0.005 (theory and FCC design)Formulae from private note of J. Gao
)(072.01
28456maxy, CEPC
IP
e
RNr
r_e is electron radiusγ= is normalized energyR is the dipole bending radiusN_IP is number of interaction points
r_p is proton radius
)(11.02 max,maxx, CEPCy
J. Gao, Nuclear Instruments and Methods in Physics Research A 533 (2004) 270–274
J. Gao, Nuclear Instruments and Methods in Physics Research A 463 (2001) 50–61
CEPC lattice with FFS
In current design:•Circumference: 52.1 km•16*arcs: 2.64 km (60 FODO)•12*short straight: 352m (8 FODO)•4*long straight: ~700 m
•Bending radius: 5.7 km•U0: 3.77GeV•Nature emittance: 7.67 nm•Nature energy spread: 0.19%•Nature bunch length : 2.82mm•Momentum compaction: 3.3E-5
(FFS)
(FFS)
Use 2 pairs of electrostatic separators Beam separated at horizontal plane with orbit offset of 5x
Maximum bunch number: 96
Pretzel scheme
Half Quad of dispersion suppressor
IP
FFS entrance condition: DX=DPX=0 x=y=0 betax=75.6m betaY=25.6m
IR optics with L*=2.5m
betaX*=0.8mbetaY*=0.0012mL*=2.5m
• We use the same method as Yunhai’s example to make a new design of CEPC FFS. 15
Total length: 170 m
IR optics with L*=1.5m
• betx*=0.8m, bety*=1.2mm, L*=1.5mIP FT CCY CCX MT
FT: final telescopic transformer
CCY: chromatic correction section y
CCX: chromatic correction section x
MT: matching telescopic transformer
The key issue of pre-CDRis to have a working FFS in CEPC with enough off-momentum dynamic apertures
Key collaboration issue now, for example
SRF parameters of CEPC
units Main Ring Booster
fRF MHz 650 1300
U0 ( single beam ) GeV 3 3
Beam current of e-&e+ mA 2*16=32 0.9
Total beam power (SR) MW 100 2.7
total RF voltage GV 7 6
Eacc MV/m 8.8 15
cavity cells 5 9
cavity numbers 720 320
Input power per cavity kW 139 20
Total RF power MW 100 6.4
LLRF station numbers 720 320
Cryo module numbers 180 (4cav/ module) 40
Another key R&D collaboration item is on CEPC SRF systems, both for main ring and for booster
SppC Technical challenges and R&D plan(Possible collaboration items)
• High field magnets: both dipoles (20 T) and quadrupoles (pole tip field: 14-20 T) are technically challenging, key technology to be solved in the coming two decades by a strong R&D program (see the next slide)
• Beam screen and vacuum: the key issue to solve the problem with very high synchrotron radiation power inside the cold vacuum. Need to develop an effective structure and working temperature to guide out the high heat load when minimizing Second-Electron-Yield, heat leakage to cold mass, impedance in the fast ramping field, vacuum instability etc. Both design and R&D efforts in the coming decade are needed to solve this critical problem.
• Collimation system: requiring unprecedentedly high efficiency, may need some collimators in cold sections. Perhaps need new method and structure. R&D efforts are needed.
R&D plan of the 20 T accelerator magnets
• 2015-2020: Development of a 12 T operational field Nb3Sn twin-aperture dipole with common coil configuration and 10-4 field quality; Fabrication and test of 2~3 T HTS (Bi-2212 or YBCO) coils in a 12 T background field and basic research on tape superconductors for accelerator magnets (field quality, fabrication method, quench protection).
• 2020-2025: Development of a 15 T Nb3Sn twin-aperture dipole and quadrupole with 10-4 field uniformity; Fabrication and test of 4~5 T HTS (Bi-2212 or YBCO) coils in a 15 T background field.
• 2025-2030: 15 T Nb3Sn coils + HTS coils (or all-HTS) to realize the 20 T dipole and quadrupole with 10-4 field uniformity; Development of the prototype SppC dipoles and quadrupoles and infrastructure build-up.
(Very Preliminary)
19
Timeline in 2014
CEPC Workshop in Shanghai Jiaotong University, Sept. 12-13, 2014
ICFA Advanced Beam Dynamics Workshop on High Luminosity Circular e+e- Colliders - Higgs Factory,
October 8-11, 2014, Beijing
Pre-CDR review: November 2014
Pre-CDR v1.0: by the end of the year 2014
CEPC/SppC long term Schedule (Preliminary)
• BEPC II will stop in ~2020
• CPEC– Pre-study, R&D and preparation work
• Pre-study: 2013-15 Pre-CDR by 2014 • R&D: 2016-2020 • Engineering Design: 2015-2020
– Construction: 2021-2027– Data taking: 2030-2036
• SPPC– Pre-study, R&D and preparation work
• Pre-study: 2013-2020• R&D: 2020-2030 • Engineering Design: 2030-2035
– Construction: 2036-2042– Data taking: 2042 -
Collaboration Issues (1)(Common and different points)
•FCC is similar to CEPC/SppC in machine and particle types
•However, there are two main differences:
(1) FCC’s priority is focusing on pp, CEPC/SppC’s priority is focusing on e+e-
(2) FCC’s CDR is due in 2018, and CEPC/SppC ‘s CDR is due in 2015 (3) CERN is running LHC (pp) with LHC upgrades following and IHEP is running BEPCII (e+e-) with CEPC/SppC following
Collaboration Issues (2)(Feature of relation between FCC and CEPC/SppC)
• FCC and CEPC/SppC represent the landscape of future super circular accelerator centers in addition to Linear one, ILC
• FCC and CEPC/SppC is complementary in particle type priority and program schedules
• FCC and CEPC/SppC is complementary in their advantages, i.e. technologies, human resources, economical potential, etc…
• In short, FCC and CEPC/SppC is of collaborative relation instead of others, which is vital for both programs
Collaboration Issues (3) (The possible mode of collaboration between FCC and CEPC/SppC)
1) Exchange visitors (Ph.D students also)2) Visitors working on both projects ( with comparisons , cross-checks,
new ideas, training students, etc., design works in the first phase)3) Joint meetings (with web-meetings), workshops, and schools, etc…4) Help each other by taking into account of differences in time and
particle type priorities…5) Key technical parameter be better same such as rf frequency6) Common design of key components, such as SCRF system…7) Joint R&D on key bottle –neck design and technology development (IR FFS design , SRF systems, High field SC magnets, Prezel
technology, for examples)
Summary (1)• FCC and CEPC+SppC are very exciting and important in
parallel to ILC, as future high energy accelerator programs
• High energy physics committee is booming with these projects and programs, especially for young generations who will continue to live and enrich the extraordinary high energy physics culture in 21th century
• Circular colliders’ beam dynamics and technologies are arrived at a good time to boom together with linear colliders, both are great heritages of high energy physics community, which are worthwhile to be preserve and to be developed
Summary (2)
• Future large collider projects are all of the nature international collaborations, both in design/construction and operation, and are for the community and by the community
• Each country, region, and the community’s efforts to probe and bridging economical resources are positive and vital to the sustainable development of the community
• Collaborations between institutions, programs and projects are vital for all, especially FCC, CEPC/SppC, and ILC.
• China HEP is open to the world for the participation and joint development
Thank you for your attention