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| MOPME002 | Simulation of the Thermal Deformation and the Cooling of a Four-rod Radio Frequency Quadrupole | 376 |
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Funding: This work is supported by the European Atomic Energy Community’s Seventh Framework Programme under grant agreement nr. 269565 (MAX project). A four-rod radio frequency quadrupole (RFQ) contains four modulated rods kept in place by a number of stems and fixed within a resonating cavity. The position and the modulation of the rods determines the focusing and accelerating properties of the RFQ. The resonating field induces currents, and by that Joule losses, in the stems, rods and tuning plates. The temperature increase causes a mechanical deformation which may lead to a deteriorated performance of the RFQ. The temperature increase is kept small by cooling the rods and stems. A new layout of cooling channels has been proposed. The paper reports about coupled electromagnetic, fluid-dynamic, thermal and structural dynamic field simulations carried out for predicting the mechanical deformation of the stems and the rods. The results for the four-rod RFQ planned for the MYRRHA proton accelerator indicate a change of 47 μm of the distance between the rods when cooling water with a velocity of 3 m/s is applied. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME002 | |
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| MOPME004 | RFQ Solver based on the Method of Moments | 382 |
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Funding: SCK•CEN The aim of this research is to improve the accuracy and the simulation time of solvers devoted to Radio Frequency Quadrupoles (RFQ). The Method of Moments is a full-wave method used to solve scattering problems. Its main advantage over FE or FDTD solvers is that unknowns are limited to the boundaries of the object. The resulting dense system of equations can be solved very rapidly with the help of domain-decomposition approaches (e.g. Macro Basis Functions*), especially when the level of detail is very fine compared to the wavelength, which is definitely the case for RFQ’s. Such a method however needs a first regularization method to overcome the low-frequency breakdown in order to compute the Macro Basis Functions. The respective field contributions of different parts of the global structure (e.g. rods vs. stems) can also easily be finely investigated. Numerical results will be presented based on the Myrrha RFQ. The low-frequency breakdown issue due to the very fine mesh will be discussed and a solution based on the so-called Loop-Tree** decomposition will be detailed. * Ozdemir, N.A.; Gonzalez-Ovejero, D.; Craeye, C., IEEE Tr.AP, vol.61, no.4, pp.2088, 2098, April 2013 ** Andriulli, F.P., IEEE Tr.AP, vol.60, no.5, pp.2347, 2356, May 2012 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME004 | |
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| THPRO099 | Toward a Virtual Accelerator Control System for the MYRRHA Linac | 3122 |
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| The MYRRHA project currently under development at Mol, Belgium, is an Accelerator Driven System expected to be operational in 2023 with the primary purpose to study the feasibility of efficiently transmuting nuclear waste products into isotopes with much shorter lifetimes. The reactor, which is expected to have a thermal power of ~70 MW, may be operated in subcritical mode when fed by spallation neutrons obtained from a 600 MeV superconducting proton linac hitting a Liquid Pb-Bi eutectic (LBE) target with an average current of 4 mA. The challenging aspect of the MYRRHA linac resides in its very high availability (close to 100%) with a Mean Time Between Failure expected to be higher than 250 hours. This paper presents the strategic approach taken during the design of the linac and its foreseen operation to fulfill this stringent requirement. In particular we will describe the concept of a beam dynamics based control system also called Virtual Accelerator which will be mandatory for the operation of such linac. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO099 | |
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| THPRO115 | Control System Design Considerations for MYRRHA ADS | 3162 |
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| The accelerator (ACC) is the first step of the accelerator driven system (ADS). A high power continuous wave ACC is required for ADS applications. An essential aspect of ACC is beam availability. It must be an order of magnitude better than current best systems. High availability is achieved by fault tolerance and redundancy of the ACC. Three factors play a key role here: use of components in a high MTBF regime, parallel and serial redundancy of components, ability to repair failing elements. In terms of ACC controls system (CS) EPICS and Linux is chosen as proven technology. High availability will be achieved through making parts of the CS redundant. Subsystems shall be redundant by design. If failure of a subsystem is detected, pre-defined scenarios should kick-in. System model or "virtual accelerator" can be implemented to predict effects of parameter change, determine required configuration of set points for optimal performance or re-configuration in case of sub-system failure. Implementation of predictive diagnostics can harvest large amount of data created by archiving service. Prediction of failure allows for controlled shutdown as opposed to abrupt stop. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO115 | |
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