Development of the CEPC collider prototype magnets

2021 ◽  
pp. 2142009
Author(s):  
Mei Yang ◽  
Fusan Chen ◽  
Xianjing Sun ◽  
Zhuo Zhang ◽  
Wen Kang ◽  
...  
Keyword(s):  
Beam Energy ◽  
Magnetic Measurement ◽  
The Other ◽  
Quadrupole Magnet ◽  
Electron Positron

A Circular Electron Positron Collider (CEPC) with a circumference of about 100 km and a beam energy up to 120 GeV is proposed to be constructed in China. Over 80% of the collider ring is covered by conventional magnets. Most dipole and quadrupole magnets are twin aperture magnets with an inter-beam separation of 350 mm. Two 1-meter-long twin aperture prototype magnets are designed and manufactured. One is a combined dipole–sextupole magnet with aluminum bus bar coils, and the other one is a twin aperture quadrupole magnet with a DT4 compensation sheet to reduce the crosstalk effect between the two apertures. The design, fabrication and magnetic measurement of two prototype magnets are described in this paper.

CEPC Z-pole polarization design studies

2021 ◽  
pp. 2142003
Author(s):  
Wenhao Xia ◽  
Jie Gao ◽  
Yiwei Wang ◽  
Dou Wang
Keyword(s):  
Beam Energy ◽  
Center Of Mass ◽  
Transverse Polarization ◽  
Beam Polarization ◽  
Energy Measurement ◽  
Design Studies ◽  
Electron Positron ◽  
Polarized Beam ◽  
Different Types ◽  
Schematic Design

In this paper, we give preliminary designs of beam polarization manipulations by inserting three different types of insertions in the Circular Electron–Positron Collider (CEPC) at center-of-mass energies of 91 GeV (Z-pole). With the wigglers in the collider ring, we can obtain 5% transverse polarization in 1.1 h for the precise energy measurement. To overcome depolarization effects as the beam energy rises from 10 GeV to 45.5 GeV in the booster ring, Siberian snakes based on helical magnets are adopted. Finally, for longitudinally polarized beam collisions, a schematic design of spin rotators based on solenoids in the collider ring is studied.

Development of an eccentric cam-based active pre-alignment system for the compact linear collider main beam quadrupole magnet

2010 ◽  
Vol 1 (MEDSI-6) ◽  
Author(s):  
F. Lackner ◽  
K. Artoos ◽  
C. Collette ◽  
H. M. Durand ◽  
C. Hauviller ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Linear Collider ◽  
Contact Region ◽  
Main Beam ◽  
Particle Accelerators ◽  
Quadrupole Magnet ◽  
Electron Positron ◽  
Alignment System ◽  
New Energy ◽  
Mechanically Stabilized

Compact linear collider (CLIC) is a study for a future electron–positron collider that would allow physicists to explore a new energy region beyond the capabilities of today's particle accelerators. The demanding transverse and vertical beam sizes and emittance specifications are resulting in stringent alignment and a nanometre stability requirement. In the current feasibility study, the main beam quadrupole magnets have to be actively pre-aligned with a precision of 1 µm in five degrees of freedom before being mechanically stabilized to the nanometre scale above 1 Hz. This contribution describes the approach of performing this active pre-alignment based on an eccentric cam system. In order to limit the amplification of the vibration sources at resonant frequencies, a sufficiently high eigenfrequency is required. Therefore, the contact region between cam and support was optimized for adequate stiffness based on the Hertzian theory. Furthermore, practical tests performed on a single-degree-of-freedom mockup will show the limitation factors and further improvements required for successful integration in a full-scale quadrupole mockup presently under design.

Beam energy spread measurement at the VEPP-4M Electron-Positron Collider

2007 ◽  
Vol 2 (06) ◽  
pp. P06001-P06001 ◽  
Author(s):  
V A Kiselev ◽  
N Yu Muchnoi ◽  
O I Meshkov ◽  
V V Smaluk ◽  
V N Zhilich ◽  
...  
Keyword(s):  
Beam Energy ◽  
Energy Spread ◽  
Electron Positron

scholarly journals General Discussion of Accretion Disks

1999 ◽  
Vol 194 ◽  
pp. 321-322
Author(s):  
Vahagn G. Gurzadyan
Keyword(s):  
Magnetic Field ◽  
Accretion Disks ◽  
Galactic Nuclei ◽  
The Other ◽  
Seminal Paper ◽  
Physical Conditions ◽  
Electron Positron ◽  
Free Parameters ◽  
The Stability ◽  
Electron Positron Pair

Even 25 years after the Shakura-Sunyaev seminal paper on the α-disk, we cannot claim that we have a reliable theory of accretion disks in galactic nuclei. Why? Because the problem is extremely complicated, it is essentially nonlinear and contains a number of parameters (i.e. is many-dimensional). The key point is whether it is possible to determine the magneto-hydrodynamical viscosity self-consistently, i.e. as a function of parameters of the disk - the temperature, matter and radiation densities, magnetic field, radius, etc., both in the radiation dominated and matter dominated regions. Another class of fundamental problems concerns the stability of the disk; Krolik mentioned only one instability - in the radiation dominated region, but there are many other types of instabilities which are quite sensitive to the physical conditions in the disk, for example, to the anisotropy of the ion pressure in the outer regions and possible electron-positron pair production near the inner edge of the disk. The other problems include those of the radiative transfer within the disk in various conditions, Comptonization of the outgoing radiation, radiation reflections by the desk, etc. Therefore it is not suprising that one can ‘explain' almost whatever he wants - spectra, variability, jets, wind, etc., by proper fit of the ‘free’ (which are never free) parameters and ignoring the instabilities and so on.

The beam energy measurement system for the Beijing electron-positron collider

2012 ◽  
Vol 225-227 ◽  
pp. 309-314 ◽  
Author(s):  
J.Y. Zhang ◽  
E.V. Abakumova ◽  
M.N. Achasov ◽  
V.E. Blinov ◽  
X. Cai ◽  
...  
Keyword(s):  
Measurement System ◽  
Beam Energy ◽  
Energy Measurement ◽  
Electron Positron

The circular electron–positron collider beam energy measurement with Compton scattering and beam tracking method

2020 ◽  
Vol 91 (3) ◽  
pp. 033109
Author(s):  
Guangyi Tang ◽  
Shanhong Chen ◽  
Yuan Chen ◽  
Zhe Duan ◽  
Manqi Ruan ◽  
...  
Keyword(s):  
Compton Scattering ◽  
Beam Energy ◽  
Energy Measurement ◽  
Tracking Method ◽  
Electron Positron ◽  
Beam Tracking

scholarly journals Circular electron-positron collider beam energy measurement scheme based on microwave-electronic Compton backscattering

2021 ◽  
Vol 70 (13) ◽  
pp. 131301-131301
Author(s):  
Dong Xu ◽  
◽  
Huang Yong-Sheng ◽  
Tang Guang-Yi ◽  
Chen Shan-Hong ◽  
...  
Keyword(s):  
Beam Energy ◽  
Energy Measurement ◽  
Measurement Scheme ◽  
Electron Positron ◽  
Compton Backscattering ◽  
Microwave Electronic

scholarly journals Electric Charge and Its Field as Deformed Space

2019 ◽  
Vol 11 (4) ◽  
pp. 29
Author(s):  
Shlomo Barak
Keyword(s):  
Fine Structure ◽  
Electric Charge ◽  
Structure Constant ◽  
Electromagnetic Theory ◽  
The Other ◽  
Fine Structure Constant ◽  
Electric Charge Density ◽  
Electron Positron ◽  
Simple Equations ◽  
First Time

The essence of electric charge has been a mystery. So far, no theory has been able to derive the attributes of electric charge, which are: bivalency, stability, quantization, equality of the absolute values of the bivalent charges, the electric field it creates and the radii of the bivalent charges. Our model of the electric charge and its field (this paper) enables us (in additional papers), for the first time, to derive simple equations for the radii and masses of the electron/positron muon/anti-muon and quarks/anti-quarks. These equations contain only the constants G, c, ℏ  and α (the fine structure constant). The calculated results based on these equations comply accurately with the experimental results. In this paper, which serves as a basis for the other papers, we define electric charge density, based on space density. This definition alone, without any phenomenology, yields the theory of Electrostatics. Electrostatics together with Lorentz Transformation is known to yield the entire Maxwell Electromagnetic theory.

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