Sub-nanometer active seismic isolator control

Balik, G.; Caron, Bernard; Allibe, Julie; Badel, Adrien; Baud, Jean Philippe; Brunetti, L.; Deleglise, Guillaume; Jérémie, A.; Breton, Ronan Le; Vilalte, S.

doi:10.1177/1045389x13500571

Cited by 11 publications

(5 citation statements)

References 8 publications

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“…Mitigation of the mechanical noises is another constraint in the reactor environment; it is however less stringent (see table 1) than on GW detectors, which are designed to sense extremely small relative changes of the two cavity arm lengths in interference (δL/L = 10 −20 at around 100 Hz [32][33][34]). To avoid strong perturbations of the cavity by the mechanical noises of the reactor environment, the optical mirrors will be implanted on specific supports already used on other large highly stabilized physics instruments [37,38].…”

Section: Photoneutralizationmentioning

confidence: 99%

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Towards a maintainable and high efficiency neutral beam system for future fusion reactors

et al. 2021

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Achievement of an economic fusion reactor imposes a high level of unprecedented requirements for neutral beam systems; the first one is the nuclear safety constraints which impose a prerequisite on the ease of access of all injector components to provide a preventive (and curative) maintenance by remote handling while maintaining reactor operation. In addition, the challenge is to develop high-power injectors with very high wall-plug efficiency (above 60%) that are able to operate in stable conditions over several months. There is a significant gap to bridge with respect to the present neutral beam systems, which are characterized by a low efficiency and by complex and long maintenance operations. Evidence that this injector concept does not offer adaptations to cope with the reactor requirements makes it clear that a new concept has to be addressed. An injector concept with modular sources at ground voltage is proposed. The concept makes remote maintenance of the injector components easier, where each source module can be replaced by a new one without breaking the vacuum and affecting injector conditioning. With the grounded and modular ion source, photoneutralization associated with energy recovery appears to be the best route capable of attaining the reactor requirements. This concept of a maintainable neutral beam system would provide a high heating power with a wall-plug efficiency above 70% and unprecedented features such as the capacity of producing temporal and spatial modulation of the beam power for a better control of the plasma stability. Up to now, photoneutralization feasibility studies already carried out on reduced-scale prototypes have not highlighted any showstoppers. Continuation of research and development in the years to come can pave the way towards the achievement of a first full-scale high-power cavity in the 1 MW range, and the realization of a multi-amperes (∼10 A) thin blade-like D− beam.

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Section: Photoneutralizationmentioning

confidence: 99%

“…They are located outside the nuclear island (see figure 18), sheltered in a bunker. To mitigate mechanical vibrations, they are mounted on active and passive vibration isolators [37,38]. The photon beams propagate in pipes connecting the injector vessel to the optical tanks.…”

Section: Design and Maintenance Of The Optical Cavitiesmentioning

confidence: 99%

Towards a maintainable and high efficiency neutral beam system for future fusion reactors

et al. 2021

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“…The frequency response function (FRF) of the transmissibility matrix can be estimated from experimental data by placing accelerometers or geophones on both the base frame and the isolated payload of the machine [12]. In, e.g., [6,13,14], several methods for transmissibility matrix measurements are developed where external shaker constructions are used to ensure that the base frame is sufficiently excited.…”

Section: Introductionmentioning

confidence: 99%

Experimental estimation of transmissibility matrices for industrial multi-axis vibration isolation systems

Beijen

Voorhoeve

Heertjes

et al. 2018

Mechanical Systems and Signal Processing

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“…They stabilize the quadrupole magnets themselves instead of steering the beam. Various active stabilization systems have been designed and tested [14][15][16]. Also a very effective passive stabilization system has been considered [17], but its large mechanical setup (100 ton concrete block and 20 air springs) limits its use to specific magnets, e.g., in the final focus system.…”

Section: Introductionmentioning

confidence: 99%

Mitigation of ground motion effects in linear accelerators via feed-forward control

Pfingstner

Artoos

Charrondiere

et al. 2014

Phys. Rev. ST Accel. Beams

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International audienceGround motion is a severe problem for many particle accelerators, since it excites beam oscillations, which decrease the beam quality and create beam-beam offset (at colliders). Orbit feedback systems can only compensate ground motion effects at frequencies significantly smaller than the beam repetition rate. In linear colliders, where the repetition rate is low, additional counter measures have to be put in place. For this reason, a ground motion mitigation method based on feed-forward control is presented in this paper. It has several advantages compared to other techniques (stabilization systems and intratrain feedback systems) such as cost reduction and potential performance improvement. An analytical model is presented that allows the derivation of hardware specification and performance estimates for a specific accelerator and ground motion model. At the Accelerator Test Facility (ATF2), ground motion sensors have been installed to verify the feasibility of important parts of the mitigation strategy. In experimental studies, it has been shown that beam excitations due to ground motion can be predicted from ground motion measurements on a pulse-to-pulse basis. Correlations of up to 80% between the estimated and measured orbit jitter have been observed. Additionally, an orbit jitter source was identified and has been removed, which halved the orbit jitter power at ATF2 and shows that the feed-forward scheme is also very useful for the detection of installation issues. We believe that the presented mitigation method has the potential to reduce costs and improve the performance of linear colliders and potentially other linear accelerators

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Sub-nanometer active seismic isolator control

Cited by 11 publications

References 8 publications

Towards a maintainable and high efficiency neutral beam system for future fusion reactors

Towards a maintainable and high efficiency neutral beam system for future fusion reactors

Experimental estimation of transmissibility matrices for industrial multi-axis vibration isolation systems

Mitigation of ground motion effects in linear accelerators via feed-forward control

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