| 1. |
|
|
| 2. |
- Goryashko, Vitaliy A., et al.
(författare)
-
A megawatt class compact power combiner for solid-state amplifiers
- 2014
-
Ingår i: Journal Electromagnetic Waves and Applications. - : Informa UK Limited. - 0920-5071 .- 1569-3937. ; 28:18, s. 2243-2255
-
Tidskriftsartikel (refereegranskat)abstract
- We propose a compact multiport two-stage combiner capable of handling peak power up to 10MW at the UHF band and suitable for particle accelerator applications. The detailed electromagnetic and thermal simulations of the combiner operating at the ESS specifications of 400kW at 352MHz are presented. At the first stage, the power is combined to a 100kW level by means of a non-resonant 12-way radial combiner, which is assumed to be fed by 8kW solid-state amplifiers. At the second stage, a waveguide combiner with T-shape couplers separated by a half-wavelength of the fundamental waveguide mode is used in order to bring the combined power to the required level. The combiner is broadband and has a relative power non-uniformity less than 5% over a 10MHz frequency band around the central frequency. The size of the proposed combiner is several times smaller than the existing ones. We also present low-power measurement results of a prototype of the radial combiner.
|
|
| 3. |
- Goryashko, Vitaliy, 1982-, et al.
(författare)
-
Proposal for Design and Test of a 352 MHz Spoke RF Source
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- More than a dozen of spoke resonators prototypes (SSR, DSR, TSR) have been constructed and tested worldwide. None have accelerated beam until now and the ESS LINAC will be the first accelerator to operate with spoke cavities. Experience with other types of superconducting cavities indicates that high-power test is vital for reliable operation of the cavity in an accelerator. Although characteristics of a bare cavity can be obtained in a low-power test some important features of a `dressed' cavity like the electroacoustic stability and tuning system can be studied only in a high-power test stand. The ESS LINAC is a pulsed machine and the Lorentz detuning originating from the electromagnetic pressure on the cavity walls is expected to be strong. The Lorentz force along with the cavity sensitivity to mechanical excitations at some resonant frequencies may lead to self-sustained mechanical vibrations which make cavity operation dicult. Practical experience shows that increasing the boundary stiness will decrease the static Lorentz force detuning but not necessarily the dynamic one. Therefore, the FREIA group at Uppsala University is building a high-power test stand able to study performance of the ESS spoke cavity at high power. The RF test stand will be able to drive the cavity not only in the self-excitation mode but also with closed RF loop and fixed frequency. The later technique will be used to reproduce the shape of the cavity voltage pulse as it is expected to be in the cavity operating in the ESS LINAC such that the cavity tuning compensation system will be tested under realistic conditions.
|
|
| 4. |
- Wedberg, Rolf, 1947-, et al.
(författare)
-
Power Supplies for Tetrode High Power Amplfiers at FREIA : ESS TDR Contribution
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper select the topology of the power supplies to the RF power amplifier to one spoke cavity to be tested at FREIA Uppsala University.The power supplies are thought to fulfill the requirements of ESS in Lund.The amplifiers pulsed operation will have a strong impact of the choice of topology. The RF amplifier will have two tetrodes in the final stage.The anode power supply is studied for different topologies and number of anodes to supply.Storing the energy for pulse current to the anodes at high voltage or at low voltage is considered.The short circuit protection can be with a crowbar or a series switch. The series switch is selected for reasons of short interrupts in case of temporary short circuits.The grid and filament supplies are thought to be standard of the shelf power supplies.Cost estimate and comments on maintenance in the end of the paper.
|
|
