R&D of CEPC injector linac

2021 ◽  
pp. 2142013
Author(s):  
Jingru Zhang ◽  
Cai Meng ◽  
Dazhang Li ◽  
Dou Wang ◽  
Guoxi Pei ◽  
...  
Keyword(s):  
Band Structure ◽  
Positron Beam ◽  
Rf System ◽  
Baseline Design ◽  
Pulse Compressor ◽  
Transverse Emittance ◽  
Key Technologies ◽  
Main Ring ◽  
Cavity Design

The CEPC includes a main ring and an injector. The injector consists of a booster and a linac. In order to meet the requirements of the booster, the baseline design of the linac is a 10 GeV electron and positron linac. Two alternative linac designs have also been introduced in this paper. For the linac baseline design, one-bunch-per-pulse is adopted. A 1.1 GeV damping ring is used to reduce the transverse emittance of positron beam. The main RF system of the linac adopts normal conducting S-band structure. Some key technologies of linac are development. The S-band structure and pulse compressor have been researched and studied. In the damping ring, two cavities used to provide 2 MV voltage. The preliminary cavity design has finished.

Melting and forefield reconnaissance technologies within TRIPLE -  accessing subglacial water reservoirs for future missions to Ocean Worlds

2021 ◽  
Author(s):  
Michael Stelzig ◽  
Jan Audehm ◽  
Ben Burgman ◽  
Fabian Becker ◽  
Lutz Deriks ◽  
...  
Keyword(s):  
Water Reservoir ◽  
Field Tests ◽  
Thick Layer ◽  
Space Missions ◽  
Global Ocean ◽  
Extraterrestrial Life ◽  
Baseline Design ◽  
Key Technologies ◽  
Ice Water

<p>Recent measurements suggest the Jovian satellite Europa as one of the most promising places to host extraterrestrial life in the Solar System. In a global ocean, well hidden by  a thick layer of ice, this moon supposedly contains more than twice as much liquid water than Earth. Many currently discussed space missions therefore aim to explore Europa’s chemical composition or investigate its habitability and even search for biosignatures.<br>The TRIPLE Project, initiated by the DLR Space Administration, comprises the development of Technologies for Rapid Ice Penetration and subglacial Lake Exploration and consists of three distinct components: (i) a melting probe, that travels through the ice and carries (ii) an autonomous nano-scale underwater vehicle (nanoAUV) that explores the ocean and takes samples to be delivered to (iii) an astrobiological laboratory. The full system should be tested in a terrestrial analog scenario in Antarctica in approximately five years as a demonstration for a future space mission. For a successful test we need a retrievable melting probe capable of penetrating several kilometres of ice while avoiding obstacles and navigating around them. It has to be able to stop and dwell at the ice-water boundary, before returning back to the surface.</p><p>This contribution focuses on TRIPLE-IceCraft and TRIPLE-FRS in which key technologies of such a melting probe are developed. </p><p>The TRIPLE-IceCraft melting probe is designed as a modular transfer system to transport standardised payloads through ice sheets of several hundred meters of thickness and penetrate into a subglacial water reservoir. Possible payloads are e.g. the nanoAUV or in-situ analysis devices for water samples such as a fluorescence spectrometer. The melting probe will be demonstrated at the Ekström shelf ice in Antarctica at the end of the project. </p><p> </p><p>The forefield reconnaissance system developed in TRIPLE-FRS combines radar and sonar techniques to benefit from both sensor principles inside ice. The radar antennas together with a specialized pulse amplifier as well as a piezoelectric acoustic transducer will directly be integrated into the melting head. To account for the respective propagation speed of electromagnetic waves, which is dependent on the surrounding ice structure, an in-situ permittivity sensor will additionally be developed. With this system, obstacles as well as the ice-water interface at the bottom of the icy layer could be detected. In order to prove the functionality and the performance of the system, several field tests on alpine glaciers will be performed during the project.</p><p>The successful demonstration of the described subsystems and key technologies represents a first milestone in the TRIPLE project line which will serve as a baseline design for the future development of space missions to Ocean Worlds as e.g. Europa.</p>

Design and beam dynamics of CEPC damping ring system

2021 ◽  
pp. 2142006
Author(s):  
Dou Wang ◽  
Xiaohao Cui ◽  
Cai Meng ◽  
Daheng Ji ◽  
Yudong Liu ◽  
...  
Keyword(s):  
Positron Beam ◽  
Ring System ◽  
Beam Dynamics ◽  
Parameter Choice ◽  
Beam Loss ◽  
Transverse Emittance ◽  
Instability Effect

A damping ring system which includes a small 1.1 GeV ring and two transport lines is introduced in CEPC linac in order to reduce the transverse emittance of positron beam at the end of linac and hence reduce the beam loss in the booster. This paper introduces the parameter choice and optics study of damping ring. The corresponding instability effect and IBS effect are also checked to make sure the design current and design emittance can be realized. Except for damping ring, two transport lines are needed to match the parameters between linac and damping ring. Both designs for energy compressor and bunch compressor including beam simulations are discussed in this paper.

INJECTION AND EXTRACTION SYSTEMS FOR THE MUON FFAG RING IN THE NEUTRINO FACTORY

2011 ◽  
Vol 26 (10n11) ◽  
pp. 1775-1784
Author(s):  
DAVID KELLIHER ◽  
SHINJI MACHIDA ◽  
M. ASLANINEJAD ◽  
J. PASTERNAK ◽  
J. SCOTT BERG ◽  
...  
Keyword(s):  
Cell Structure ◽  
Time Of Flight ◽  
Small Time ◽  
Extraction System ◽  
Neutrino Factory ◽  
Transverse Emittance ◽  
Main Ring

Non-scaling FFAG (NS-FFAG) rings have been proposed as a solution for muon acceleration in the Neutrino Factory. In order to achieve small orbit excursion and small time of flight variation, lattices with a very compact cell structure and consequent short straight sections are required. The resulting geometry, combined with the large transverse emittance of the muon bunch, places very challenging constraints on the injection/extraction systems. The injection/extraction system requires a set of distributed kickers, a superconducting septum and increased aperture in some of the main ring magnets. A scheme for both injection and extraction for a FFAG with triplet geometry is presented. In addition, a solution for the required kicker magnets is proposed.

Effects of Phonological Decoding Training on Children's Word Recognition of CVC, CV, and VC Structures

1996 ◽  
Vol 5 (1) ◽  
pp. 67-78 ◽  
Author(s):  
Kenyatta O. Rivers ◽  
Linda J. Lombardino ◽  
Cynthia K. Thompson
Keyword(s):  
Word Recognition ◽  
Multiple Baseline ◽  
Single Subject ◽  
Group Training ◽  
Complex Structures ◽  
Multiple Baseline Design ◽  
Baseline Design ◽  
Phonological Decoding ◽  
The Third ◽  
Letter Sound

The effects of training in letter-sound correspondences and phonemic decoding (segmenting and blending skills) on three kindergartners' word recognition abilities were examined using a single-subject multiple-baseline design across behaviors and subjects. Whereas CVC pseudowords were trained, generalization to untrained CVC pseudowords, untrained CVC real words, untrained CV and VC pseudowords, and untrained CV and VC real words were assessed. Generalization occurred to all of the untrained constructions for two of the three subjects. The third subject did not show the same degree of generalization to VC pseudowords and real words; however, after three training sessions, this subject read all VC constructions with 100% accuracy. Findings are consistent with group training studies that have shown the benefits of decoding training on word recognition and spelling skills and with studies that have demonstrated the effects of generalization to less complex structures when more complex structures are trained.

Generalized Learning of Receptive and Expressive Action-Object Responses by Language-Delayed Preschoolers

1990 ◽  
Vol 55 (4) ◽  
pp. 665-678 ◽  
Author(s):  
Beth A. Mineo ◽  
Howard Goldstein
Keyword(s):  
Developmentally Delayed ◽  
Matrix Training ◽  
Lexical Knowledge ◽  
Baseline Design ◽  
Recombinative Generalization ◽  
Word Combination ◽  
Expressive Performance ◽  
Preschool Boys ◽  
Linguistic Aspect ◽  
Multiple Probe

This study examined the effectiveness of matrix-training procedures in teaching action + object utterances in both the receptive and expressive language modalities. The subjects were 4 developmentally delayed preschool boys who failed to produce spontaneous, functional two-word utterances. A multiple baseline design across responses with a multiple probe technique was employed. Subjects were taught 4–6 of 48 receptive and 48 expressive responses. Acquisition of a word combination rule was facilitated by the use of familiar lexical items, whereas subsequent acquisition of new lexical knowledge was enhanced by couching training in a previously trained word combination pattern. Although receptive knowledge was not sufficient for the demonstration of corresponding expressive performance for most of the children, only minimal expressive training was required to achieve this objective. For most matrix items, subjects responded receptively before they did so expressively. For 2 subjects, when complete receptive recombinative generalization had not been achieved, expressive training facilitated receptive responding. The results of this study elucidate benefits to training one linguistic aspect (lexical item, word combination pattern) at a time to maximize generalization in developmentally delayed preschoolers.

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