A global ionosphere scintillation propagation model for equatorial regions

The formulation of a wave propagation model through a turbulent ionosphere is presented. The calculation of the transmitted field enables the estimation of signal impairments, especially its intensity and phase fluctuations. The model outputs are compared with measurement results. This was performed for the intensity and phase fluctuation levels and for the spectral content of the transmitted signal. The field second-order moment calculation is then presented. The mutual coherence function characterizes the channel transfer function. It is required for radar performances assessment after propagation through the turbulent medium. It was demonstrated that under simplified hypothesis, an analytical solution can be derived allowing a sensitivity analysis study

A global ionosphere scintillation propagation model for equatorial regions

The formulation of a wave propagation model through a turbulent ionosphere is presented. The calculation of the transmitted field enables the estimation of signal impairments, especially its intensity and phase fluctuations. The model outputs are compared with measurement results. This was performed for the intensity and phase fluctuation levels and for the spectral content of the transmitted signal. The field second-order moment calculation is then presented. The mutual coherence function characterizes the channel transfer function. It is required for radar performances assessment after propagation through the turbulent medium. It was demonstrated that under simplified hypothesis, an analytical solution can be derived allowing a sensitivity analysis study

Klystron efficiency optimization based on a genetic algorithm

This paper presents a method based on a genetic algorithm optimization to design a high efficient klystron, operating in the X band. First, the genetic algorithm is used to optimize the bunching circuit and then to optimize the geometry of the output cavity. Finally the output cavity is integrated to the bunching circuit and the achieved efficiency is about 70%

RFQ NEWGAIN: RF and Thermomechanical Design

International audienceA new injector called NEWGAIN will be added to the SPIRAL2 Linear Accelerator (LINAC), in parallel with the existing one. It will be mainly composed of an ion source and a Radio Frequency Quadrupole (RFQ) connected to the superconductive LINAC of SPIRAL2. The new RFQ will accelerate at 88.05 MHz particles with charge-over-mass ratio (Q/A) between 1/3 and 1/7, from 10 keV/u up to 590 keV/u. It consists of a 4-vane resonant cavity with a total length of 7 m. It is a CW machine that has to show stable operation, provide the request availability, have the minimum losses in order to provide the highest current to the superconductive LINAC and show the best quality/cost ratio. This paper will present the preliminary RF design and the thermomechanical study for this RFQ

Fabrication and test of a 5 GHz kladistron

A 5 GHz klystron of type “kladistron” has been designed and realized. It was adapted from the TH2166 from Thales, where the interaction line was transformed from 6 to 16 cavities. This klystron was fabricated and tested at Thales. The results of these tests are presented and discussed in this paper

Calcul de la SER d'une frégate

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ESS RFQ: Installation and Tuning at Lund

International audienceThe 352 MHz Radio Frequency Quadrupole (RFQ) for the European Spallation Source ERIC (ESS) has been delivered by the end of 2019. It has been provided by CEA, IRFU, Saclay/France. It consists of five sections with a total length of 4.6 m and accelerates the 70 mA proton beam from 75 keV up to 3.6 MeV. It will be fed with 900 kW peak power through two coaxial loop couplers. The installation process (alignment, vacuum test), as well as the tuning process based on bead-pull measurements, is presented in this paper

Design, Fabrication, and Test of a 5 GHz Klystron Based on the Kladistron Principle

A new bunching method, named “kladistron” has been developed at CEA in order to provide high-efficiency klystrons. A first “kladistron” prototype was designed and realized. It was adapted from the 4.9-GHz TH2166 from Thales, where the interaction line was transformed from six to 16 cavities. The design and fabrication phases of this prototype are developed in this article. The kladistron prototype was tested in Thales facility. Its efficiency is finally lower (41%) than expected (55%), moreover it presents a spurious oscillation at 4.96 GHz. After analysis of the experimental results, it is concluded that the discrepancy between design and real frequencies is the cause for the low efficiency while the spurious oscillation results from a high gain peak at 4.96 GHz

ESS RFQ Electromagnetic Simulations Using CST Studio Suite

International audienceThe Radio Frequency Quadrupole (RFQ) of the European Spallation Source (ESS), operates at 352.21 MHz with an RF pulse length of 3.2 ms and repetition rate of 14 Hz. The RFQ focuses, bunches and accelerates the 62.5 mA proton beam from 75 keV up to 3.6 MeV. In an effort to study and compare the results from 3D electromagnetic codes, different models of the RFQ were simulated with CST Studio suite. This paper presents the selection of optimal parameters for simulation of the RFQ cavity voltage and comparison of the results with the RFQ design code Toutatis