Design and beam dynamics of the CEPC booster

2020 ◽  
Vol 35 (15n16) ◽  
pp. 2041007
Author(s):  
Dou Wang ◽  
Chenghui Yu ◽  
Xiaohao Cui ◽  
Daheng Ji ◽  
Yudong Liu ◽  
...  
Keyword(s):  
Specific Energy ◽  
Beam Energy ◽  
Beam Dynamics ◽  
Modes Of Operation ◽  
Injection Speed ◽  
Dynamic Aperture ◽  
Positron Beams

The CEPC booster needs to provide electron and positron beams to the collider at different energy with required injection speed. A 10 GeV linac is adopted as the injector for CDR. Then the beam energy is accelerated to specific energy according to three modes of operation of the CEPC collider ring ([Formula: see text], [Formula: see text] and [Formula: see text]). The geometry of the booster is designed carefully in order to share the same tunnel with the collider. The design status of the booster with the CDR lattice including parameters, optics and dynamic aperture is discussed in this paper.

scholarly journals Machine Learning Applied to the Analysis of Nonlinear Beam Dynamics Simulations for the CERN Large Hadron Collider and Its Luminosity Upgrade

Information ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 53
Author(s):  
Massimo Giovannozzi ◽  
Ewen Maclean ◽  
Carlo Emilio Montanari ◽  
Gianluca Valentino ◽  
Frederik F. Van der Veken
Keyword(s):  
Machine Learning ◽  
Large Hadron Collider ◽  
Performance Optimization ◽  
Hadron Collider ◽  
High Energy ◽  
Beam Dynamics ◽  
Machine Learning Techniques ◽  
Nonlinear Beam ◽  
Dynamic Aperture ◽  
Advanced Analysis

A Machine Learning approach to scientific problems has been in use in Science and Engineering for decades. High-energy physics provided a natural domain of application of Machine Learning, profiting from these powerful tools for the advanced analysis of data from particle colliders. However, Machine Learning has been applied to Accelerator Physics only recently, with several laboratories worldwide deploying intense efforts in this domain. At CERN, Machine Learning techniques have been applied to beam dynamics studies related to the Large Hadron Collider and its luminosity upgrade, in domains including beam measurements and machine performance optimization. In this paper, the recent applications of Machine Learning to the analyses of numerical simulations of nonlinear beam dynamics are presented and discussed in detail. The key concept of dynamic aperture provides a number of topics that have been selected to probe Machine Learning. Indeed, the research presented here aims to devise efficient algorithms to identify outliers and to improve the quality of the fitted models expressing the time evolution of the dynamic aperture.

SPPC/CEPC lattice design and beam dynamics study

2017 ◽  
Vol 32 (34) ◽  
pp. 1746005 ◽  
Author(s):  
Feng Su ◽  
Jie Gao ◽  
Yukai Chen ◽  
Jingyu Tang ◽  
Yiwei Wang ◽  
...  
Keyword(s):  
Beam Dynamics ◽  
Parameter Choice ◽  
Proton Proton ◽  
Double Ring ◽  
Lattice Design ◽  
Dynamic Aperture

In this paper, we introduced the parameter choice and the first version lattice design for a 61 km and 100-km Super Proton–Proton Collider (SPPC). We started the lattice design and the beam dynamics study from last year and showed the preliminary dynamic aperture result of these two SPPC lattice versions. We also showed the layout, the lattice design and the dynamic aperture study of a CEPC partial double ring, an advanced partial double ring and a fully partial double ring schemes.

scholarly journals Magnet Lattice Optimization for Novosibirsk Fourth Generation Light Source SKIF

2020 ◽  
Vol 15 (1) ◽  
pp. 5-23
Author(s):  
Grigory N. Baranov ◽  
Anton V. Bogomyagkov ◽  
Eugene B. Levichev ◽  
Sergey V. Sinyatkin
Keyword(s):  
Electron Beam ◽  
Light Source ◽  
Beam Energy ◽  
Fourth Generation ◽  
Beam Lifetime ◽  
Dynamic Aperture ◽  
Photon Source ◽  
Low Emittance

We study magnetic lattice and optimize parameters for the fourth generation light source SKIF (Russian acronym of Siberian Circular Photon Source) to be built in Novosibirsk. We consider several lattice cells to achieve both low emittance and large dynamic aperture. The resulting lattice provides the natural emittance of the electron beam of 75 pm for the beam energy of 3 GeV and the orbit circumference of 476 m. Only two families of chromatic sextupoles give the dynamic aperture and energy bandwidth enough for both good beam lifetime and simple effective injection.

Design study of CEPC lower emittance booster

2021 ◽  
pp. 2142014
Author(s):  
Dou Wang ◽  
Yuemei Peng ◽  
Xiaohao Cui ◽  
Daheng Ji ◽  
Yudong Liu ◽  
...  
Keyword(s):  
Design Study ◽  
Injection Efficiency ◽  
Injection Scheme ◽  
Safety And Reliability ◽  
Dynamic Aperture ◽  
Positron Beams ◽  
Better Than

The CEPC booster needs to provide electron and positron beams to the collider at different energy with required injection efficiency. At Higgs energy, only the on-axis injection from booster to collider can be fulfilled in CDR. With a consideration of keeping the off-axis injection scheme for safety and reliability, a new booster design based on TME lattice is considered to reduce the emittance by three times after CDR. The new booster design has reached an emittance of 1.3 nm at 120 GeV and the DA without errors is even better than CDR. The geometry of new booster is designed carefully in order to share the same tunnel with collider. The design status of CEPC new booster including parameters, optics, dynamic aperture and geometry is discussed in this paper.

scholarly journals A conceptual design of circular Higgs factory

2016 ◽  
Vol 31 (33) ◽  
pp. 1644012 ◽  
Author(s):  
Yunhai Cai
Keyword(s):  
Beam Energy ◽  
Beam Dynamics ◽  
Large Momentum ◽  
Electron Beam Energy ◽  
Additional Challenge ◽  
Beam Lifetime ◽  
Strong Focusing ◽  
Advanced Analysis ◽  
Momentum Acceptance ◽  
Low Emittance

Similar to a super B-factory, a circular Higgs factory (CHF) will require strong focusing systems near the interaction points and a low-emittance lattice in the arcs to achieve a factory luminosity. At electron beam energy of 125 GeV, beamstrahlung effects during the collision pose an additional challenge to the collider design. In particular, a large momentum acceptance at the 2% level is necessary to retain an adequate beam lifetime. This turns out to be the most challenging aspect in the design of a CHF. In this paper, an example will be provided to illustrate the beam dynamics in a CHF, emphasizing the chromatic optics. Basic optical modules and advanced analysis will be presented. Most importantly, we will show that 2% momentum aperture is achievable.

scholarly journals Nonlinear dynamics of proton beams with hollow electron lens in the CERN high-luminosity LHC

2021 ◽  
Vol 137 (1) ◽  
Author(s):  
D. Mirarchi ◽  
R. B. Appleby ◽  
R. Bruce ◽  
M. Giovannozzi ◽  
A. Mereghetti ◽  
...  
Keyword(s):  
Beam Energy ◽  
Hadron Collider ◽  
Beam Dynamics ◽  
Stored Energy ◽  
High Luminosity ◽  
Permanent Damage ◽  
Beam Halo ◽  
Electron Lens ◽  
Diffusion Speed ◽  
Advanced Tool

AbstractThe design stored beam energy in the CERN high-luminosity large hadron collider (HL-LHC) upgrade is about 700 MJ, with about 36 MJ in the beam tails, according to estimates based on scaling considerations from measurements at the LHC. Such a large amount of stored energy in the beam tails poses serious challenges on its control and safe disposal. In particular, orbit jitters can cause significant losses on primary collimators, which can lead to accidental beam dumps, magnet quenches, or even permanent damage to collimators and other accelerator elements. Thus, active control of the diffusion speed of halo particles is necessary and the use of hollow electron lenses (HELs) represents the most promising approach to handle overpopulated tails at the HL-LHC. HEL is a very powerful and advanced tool that can be used for controlled depletion of beam tails, thus enhancing the performance of beam halo collimation. For these reasons, HELs have been recently included in the HL-LHC baseline. In this paper, we present detailed beam dynamics calculations performed with the goal of defining HEL specifications and operational scenarios for HL-LHC. The prospects for effective halo control in HL-LHC are presented.

Edge Penetration Effects in the Low-Loss Electron Image in the SEM

1988 ◽  
Vol 46 ◽  
pp. 202-203
Author(s):  
Oliver C. Wells
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Beam Energy ◽  
Secondary Electron ◽  
Sharp Edge ◽  
Beam Diameter ◽  
Low Loss ◽  
Additional Information ◽  
Electron Image ◽  
Scanning Electron

The low-loss electron (LLE) image in the scanning electron microscope (SEM) is useful for the study of uncoated photoresist and some other poorly conducting specimens because it is less sensitive to specimen charging than is the secondary electron (SE) image. A second advantage can arise from a significant reduction in the width of the “penetration fringe” close to a sharp edge. Although both of these problems can also be solved by operating with a beam energy of about 1 keV, the LLE image has the advantage that it permits the use of a higher beam energy and therefore (for a given SEM) a smaller beam diameter. It is an additional attraction of the LLE image that it can be obtained simultaneously with the SE image, and this gives additional information in many cases. This paper shows the reduction in penetration effects given by the use of the LLE image.

Electron beam induced current study of thin silicon layers on insulator substrate

1990 ◽  
Vol 48 (4) ◽  
pp. 618-619
Author(s):  
A. Buczkowski ◽  
Z. J. Radzimski ◽  
J. C. Russ ◽  
G. A. Rozgonyi
Keyword(s):  
Electron Beam ◽  
Energy Loss ◽  
Beam Energy ◽  
Collection Efficiency ◽  
Silicon Layer ◽  
Depletion Layer ◽  
Incident Electron Energy ◽  
Induced Current ◽  
Electron Hole ◽  
Electron Beam Induced Current

If a thickness of a semiconductor is smaller than the penetration depth of the electron beam, e.g. in silicon on insulator (SOI) structures, only a small portion of incident electrons energy , which is lost in a superficial silicon layer separated by the oxide from the substrate, contributes to the electron beam induced current (EBIC). Because the energy loss distribution of primary beam is not uniform and varies with beam energy, it is not straightforward to predict the optimum conditions for using this technique. Moreover, the energy losses in an ohmic or Schottky contact complicate this prediction. None of the existing theories, which are based on an assumption of a point-like region of electron beam generation, can be used satisfactorily on SOI structures. We have used a Monte Carlo technique which provide a simulation of the electron beam interactions with thin multilayer structures. The EBIC current was calculated using a simple one dimensional geometry, i.e. depletion layer separating electron- hole pairs spreads out to infinity in x- and y-direction. A point-type generation function with location being an actual location of an incident electron energy loss event has been assumed. A collection efficiency of electron-hole pairs was assumed to be 100% for carriers generated within the depletion layer, and inversely proportional to the exponential function of depth with the effective diffusion length as a parameter outside this layer. A series of simulations were performed for various thicknesses of superficial silicon layer. The geometries used for simulations were chosen to match the "real" samples used in the experimental part of this work. The theoretical data presented in Fig. 1 show how significandy the gain decreases with a decrease in superficial layer thickness in comparison with bulk material. Moreover, there is an optimum beam energy at which the gain reaches its maximum value for particular silicon thickness.

Surface recombination effects on minority carrier diffusion length measurements using electron beam-induced current

1990 ◽  
Vol 48 (4) ◽  
pp. 744-745
Author(s):  
D.P. Malta ◽  
M.L. Timmons
Keyword(s):  
Electron Beam ◽  
Beam Energy ◽  
Minority Carrier ◽  
Diffusion Length ◽  
Effective Diffusion ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Logarithmic Scale ◽  
Minority Carrier Diffusion Length ◽  
Carrier Diffusion

Measurement of the minority carrier diffusion length (L) can be performed by measurement of the rate of decay of excess minority carriers with the distance (x) of an electron beam excitation source from a p-n junction or Schottky barrier junction perpendicular to the surface in an SEM. In an ideal case, the decay is exponential according to the equation, I = Ioexp(−x/L), where I is the current measured at x and Io is the maximum current measured at x=0. L can be obtained from the slope of the straight line when plotted on a semi-logarithmic scale. In reality, carriers recombine not only in the bulk but at the surface as well. The result is a non-exponential decay or a sublinear semi-logarithmic plot. The effective diffusion length (Leff) measured is shorter than the actual value. Some improvement in accuracy can be obtained by increasing the beam-energy, thereby increasing the penetration depth and reducing the percentage of carriers reaching the surface. For materials known to have a high surface recombination velocity s (cm/sec) such as GaAs and its alloys, increasing the beam energy is insufficient. Furthermore, one may find an upper limit on beam energy as the diameter of the signal generation volume approaches the device dimensions.

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