RF parameters design for a Circular Electron–Positron Collider

2021 ◽  
pp. 2142004
Author(s):  
Dianjun Gong ◽  
Jie Gao ◽  
Jiyuan Zhai
Keyword(s):  
System Design ◽  
Double Ring ◽  
Beam Loading ◽  
Electron Positron ◽  
Loading Effects ◽  
Analytical Formulas ◽  
Preliminary Study ◽  
First Time ◽  
Conceptual Design Report ◽  
General Method

Radio frequency (RF) parameters design is an important part in RF system design. In this paper we will introduce a general method of choosing appropriate RF parameters for a circular [Formula: see text] collider. The RF parameters are determined with several analytical formulas. With this method, the RF parameters of the Circular Electron–Positron Collider (CEPC) for Conceptual Design Report (CDR) are verified. A new set of RF parameters for the CEPC with 1-cell LG Nb cavities is also designed. Besides, the RF parameters of the CEPC Advanced Partial Double Ring (APDR) and the CEPC Damping Ring (DR) are designed for the first time, and a preliminary study of the beam loading effects of APDR and DR is also carried out.

Design of CEPC superconducting RF system

2019 ◽  
Vol 34 (13n14) ◽  
pp. 1940006 ◽  
Author(s):  
Jiyuan Zhai ◽  
Dianjun Gong ◽  
Hongjuan Zheng ◽  
Peng Sha ◽  
Qiang Ma ◽  
...  
Keyword(s):  
Center Of Mass ◽  
Rf System ◽  
Production Threshold ◽  
Center Of Mass Energy ◽  
Double Ring ◽  
Beam Loading ◽  
Electron Positron ◽  
Wide Range ◽  
Superconducting Rf ◽  
Conceptual Design Report

CEPC is a 100-km double-ring circular electron–positron collider operating at 90–240 GeV center-of-mass energy of Z-pole, WW-pair production threshold and Higgs resonance. The conceptual design report (CDR) of CEPC has been published as an important step to move the project forward. The superconducting RF (SRF) system is one of the most important and challenging accelerator systems due to the wide range of beam energy and current. In this paper, the layout, parameters and configuration of the superconducting RF system for the CEPC collider ring will be introduced. Issues of beam cavity interactions including transient beam loading and coupled-bunch instabilities of accelerating mode are discussed.

Beam–beam effects of single ring and partial double ring scheme in CEPC

2016 ◽  
Vol 31 (33) ◽  
pp. 1644015 ◽  
Author(s):  
Yuan Zhang
Keyword(s):  
High Energy Physics ◽  
High Energy ◽  
Effect Study ◽  
Double Ring ◽  
Physics Community ◽  
Single Ring ◽  
Beam Interaction ◽  
First Time ◽  
Conceptual Design Report ◽  
Energy Physics

After the Higgs discovery, it is believed that a circular [Formula: see text] collider could serve as a Higgs factory. The high energy physics community in China launched a study of a 50–100 km ring collider. A preliminary conceptual design report (Pre-CDR) has been published in early 2015. This report is based on a 54-km ring design. Some progress on beam–beam effect study after Pre-CDR is shown in the paper. We estimate the beamstrahlung lifetime using a pure strong–strong code as a comparison with the result obtained using a quasi-strong–strong method. The effect of parasitic crossing in the pretzel scheme is also estimated for the very first time. The feasibility of the main parameters for partial double ring scheme are evaluated from the point view of beam–beam interaction.

scholarly journals FCC-ee: the synthesis of a long history of e+e- circular colliders

2021 ◽  
Vol 136 (9) ◽  
Author(s):  
K. Oide ◽  
J. Wenninger
Keyword(s):  
Small Scale ◽  
Vacuum Chambers ◽  
Double Ring ◽  
Electron Positron ◽  
Beam Lifetime ◽  
History Of ◽  
Beam Parameters ◽  
And Performance ◽  
Beam Currents ◽  
First Time

AbstractThe design of FCC-ee is relying on the accumulated experience of $$\mathrm {e^{+}e^{-}}$$ e + e - colliders that have been designed, constructed and operated in the past 40 years. FCC-ee will surpass the 26.7 km long Large Electron Positron collider LEP by a factor 4 in size. Like for LEP the large size is justified by the need to control the synchrotron radiation losses that for both machines reach a few percent per turn. To that end LEP had the first large super-conducting (SC) RF system with around 3.8 GV of accelerating voltage. LEP achieved for the first time very large beam-beam parameters of around 0.08, and it relied on transversely polarized beams to determine accurately the beam energy for the experiments. The DA$$\varPhi $$ Φ NE collider, together with PEP II and KEKB split the two beams into separate vacuum chambers to reach much higher Ampere-level beam currents. To overcome beam-beam lifetime and performance issues DA$$\varPhi $$ Φ NE used for the first time the Crab Waist concept for the interaction region (IR) optics. The B-factories, PEP-II and KEKB have verified the double-ring $$\mathrm {e^{+}e^{-}}$$ e + e - collider with multi-ampere stored currents for over 1000 bunches, small $$\beta ^*$$ β ∗ , top-up injection, and achieved then-highest luminosity. KEKB has applied 22-mrad crossing angle at the IP with crab crossing. Both machines inherited accelerator techniques from their predecessors, PEP and TRISTAN, which was a small-scale LEP. Currently the next generation SuperKEKB collider is starting up. It has already achieved some milestones required for FCC-ee such as small $$\beta ^*$$ β ∗ (0.8 mm) and virtual crab-waist scheme with a large Piwinski angle (>10).

scholarly journals Imaging the Human Thyroid Using Three-Dimensional Diffuse Optical Tomography: A Preliminary Study

2021 ◽  
Vol 11 (4) ◽  
pp. 1670
Author(s):  
Tetsuya Mimura ◽  
Shinpei Okawa ◽  
Hiroshi Kawaguchi ◽  
Yukari Tanikawa ◽  
Yoko Hoshi
Keyword(s):  
Optical Tomography ◽  
Tumor Hypoxia ◽  
Three Dimensional ◽  
Diffuse Optical Tomography ◽  
Element Model ◽  
Needle Aspiration ◽  
Human Thyroid ◽  
Tissue Oxygen Saturation ◽  
Preliminary Study ◽  
First Time

Thyroid cancer is usually diagnosed by ultrasound imaging and fine-needle aspiration biopsy. However, diagnosis of follicular thyroid carcinomas (FTC) is difficult because FTC lacks nuclear atypia and a consensus on histological interpretation. Diffuse optical tomography (DOT) offers the potential to diagnose FTC because it can measure tumor hypoxia, while image reconstruction of the thyroid is still challenging mainly due to the complex anatomical features of the neck. In this study, we attempted to solve this issue by creating a finite element model of the human neck excluding the trachea (a void region). By reconstruction of the absorption coefficients at three wavelengths, 3D tissue oxygen saturation maps of the human thyroid are obtained for the first time by DOT.

scholarly journals Control of electron beam energy-spread by beam loading effects in a laser-plasma accelerator

2020 ◽  
Vol 62 (5) ◽  
pp. 055004 ◽  
Author(s):  
Guangyu Li ◽  
Quratul Ain ◽  
Song Li ◽  
Muhammad Saeed ◽  
Daniel Papp ◽  
...  
Keyword(s):  
Electron Beam ◽  
Laser Plasma ◽  
Beam Energy ◽  
Plasma Accelerator ◽  
Energy Spread ◽  
Electron Beam Energy ◽  
Beam Loading ◽  
Loading Effects ◽  
Laser Plasma Accelerator

General method for cloning Neurospora crassa nuclear genes by complementation of mutants

1985 ◽  
Vol 5 (9) ◽  
pp. 2272-2278
Author(s):  
R A Akins ◽  
A M Lambowitz
Keyword(s):  
Neurospora Crassa ◽  
Genomic Library ◽  
Selection Procedure ◽  
Nuclear Genes ◽  
Shuttle Vectors ◽  
Sib Selection ◽  
First Time ◽  
Very High ◽  
Restriction Site Polymorphisms ◽  
General Method

We have developed a sib selection procedure for cloning Neurospora crassa nuclear genes by complementation of mutants. This procedure takes advantage of a modified N. crassa transformation procedure that gives as many as 10,000 to 50,000 stable transformants per microgram of DNA with recombinant plasmids containing the N. crassa qa-2+ gene. Here, we describe the use of the sib selection procedure to clone genes corresponding to auxotrophic mutants, nic-1 and inl. The identities of the putative clones were confirmed by mapping their chromosomal locations in standard genetic crosses and using restriction site polymorphisms as genetic markers. Because we can obtain very high N. crassa transformation frequencies, cloning can be accomplished with as few as five subdivisions of an N. crassa genomic library. The sib selection procedure should, for the first time, permit the cloning of any gene corresponding to an N. crassa mutant for which an appropriate selection can be devised. Analogous procedures may be applicable to other filamentous fungi before the development of operational shuttle vectors.

scholarly journals Relativistic shock waves induced by ultra-high laser pressure

2014 ◽  
Vol 32 (2) ◽  
pp. 243-251 ◽  
Author(s):  
Shalom Eliezer ◽  
Noaz Nissim ◽  
Erez Raicher ◽  
José Maria Martínez-Val
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Laser Irradiance ◽  
Compression Pressure ◽  
Relativistic Shock ◽  
Electron Positron ◽  
High Laser ◽  
Wave Compression ◽  
The One ◽  
First Time

AbstractThis paper analyzes the one dimensional shock wave created in a planar target by the ponderomotive force induced by very high laser irradiance. The laser-induced relativistic shock wave parameters, such as compression, pressure, shock wave and particle flow velocities, sound velocity and temperature are calculated here for the first time in the context of relativistic hydrodynamics. For solid targets and laser irradiance of about 2 × 1024 W/cm2, the shock wave velocity is larger than 50% of the speed of light, the shock wave compression is larger than 4 (usually of the order of 10) and the targets have a pressure of the order of 1015 atmospheres. The estimated temperature can be larger than 1 MeV in energy units and therefore very excited physics (like electron positron formation) is expected in the shocked area. Although the next generation of lasers might allow obtaining relativistic shock waves in the laboratory this possibility is suggested in this paper for the first time.

Parent-Child Profile Similarity and Aggression: A Preliminary Study

1966 ◽  
Vol 18 (2) ◽  
pp. 440-442 ◽  
Author(s):  
James Neal Butcher ◽  
David M. Messick
Keyword(s):  
Teacher Ratings ◽  
Adolescent Aggression ◽  
Profile Similarity ◽  
Child Personality ◽  
Preliminary Study ◽  
Personality Similarity ◽  
The Relationship ◽  
Mmpi Profile ◽  
General Method ◽  
Parent Child

This investigation was directed toward studying the relationship between parent-child personality similarity and adolescent aggression and to illustrate the utility of a general method of assessing profile similarity suggested by Overall (1964). Peer and teacher ratings of aggression were used to group eighth-grade boys on manifest aggression. Ss and their parents (volunteers) were administered the MMPI. The d∗ measure of dissimilarity was used to compare parent-child profile configurations in the three aggression groups. Although the small and biased sample preclude major conclusions, the results support the use of the d∗ statistic for assessing MMPI profile similarity and suggest that further work in the area of parent-child personality similarity might be fruitful.

An Effective Synthesis of N,N-Diphenyl Carbazolium Salts

Synlett ◽  
2017 ◽  
Vol 29 (10) ◽  
pp. 1314-1318 ◽  
Author(s):  
Charles Diesendruck ◽  
Sinai Aharonovich ◽  
Nansi Gjineci ◽  
Dario Dekel
Keyword(s):  
Positive Charge ◽  
Quaternary Ammonium Salts ◽  
Simple Approach ◽  
Ammonium Salts ◽  
State Structure ◽  
Pi Systems ◽  
Effective Synthesis ◽  
Short Time ◽  
First Time ◽  
General Method

Tetraaryl ammonium salts are a synthetic challenge, since there is no general method for the arylation of triaryl amines. Contrary to other quaternary ammonium salts, tetraaryl ammonium salts should be very chemically stable. The ipso carbons are not very electrophilic, since the positive charge is distributed throughout the pi systems and they have no acidic β hydrogens. Here we demonstrate a simple approach to N,N-diphenyl carbazolium salts using only three synthetic steps, allowing for an easy production of these salts in large amounts and in a relatively short time. In addition, we study the Cu(I) catalyzed multi-arylation of 2,2’-diaminobiphenyl, focusing on the regioselectivity of each step. Finally, we characterize, for the first time, the solid state structure of a tetraaryl ammonium salt.

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