Dynamic effects and their control at the LHC

Bailey, R.; Bordry, F.; Bottura, L.; Burla, P.; Collier, P.; Henrichsen, K.N.; Koutchouk, Jean‐Pierre; Lauckner, R.; Parker, R.; Pett, J.; Proudlock, P.; Schmickler, H.; Schmidt, R.; Walckiers, L.; Wolf, R.

doi:10.1109/pac.1997.749545

Cited by 5 publications

(4 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For a given normal harmonic and considering only linear contributions, the model has the form: (2) where is the direct current components, is the alternate current components for short term effects ( 1 s) and is the alternate current components for long term effects ( 100 s). The model is also valid for any skew harmonic .…”

Section: The Linear Field Modelmentioning

confidence: 99%

See 1 more Smart Citation

The Multipoles Factory: an element of the LHC control

Amet

Bottura

Deniau

et al. 2002

IEEE Trans. Appl. Supercond.

Self Cite

View full text Add to dashboard Cite

Abstract-The measurements performed at CERN on prototypes and first pre-series main dipole magnets confirm the need of an active control of the Large Hadron Collider to compensate the dynamic field changes during the proton beam injection and acceleration. This control requires in turn an accurate forecast of the magnetic field in the accelerator. We plan to predict the field on the basis of two elements: theoretical field models tailored through the accumulated knowledge of the main magnets during series tests, and an on-line measurement system running on few reference magnets tracking the LHC current cycle. Data coming from this "Multipoles Factory" will result from the fusion of the two sources. Based on this system we foresee to deliver calibration information for pre-defined accelerator cycles as well as real time information for the active control. In this paper we report the conceptual design of the system, and we discuss the features and performance of the models that we have developed for the field forecast.

show abstract

Section: The Linear Field Modelmentioning

confidence: 99%

“…The constrains on the field quality [1], [2] has lead to design a Multipoles Factory (MF) as an important element of the LHC control.…”

Section: Introduction and Notationsmentioning

confidence: 99%

The Multipoles Factory: an element of the LHC control

Amet

Bottura

Deniau

et al. 2002

IEEE Trans. Appl. Supercond.

Self Cite

View full text Add to dashboard Cite

show abstract

“…During the field ramp, coupling currents are induced between the filaments inside the strands and between the strands in the cable. This leads to energy loss and field distortions, both systematic and random, that may deteriorate the accelerator performance [2], [3].…”

Section: Introductionmentioning

confidence: 99%

Multipoles Induced by Inter-Strand Coupling Currents in LARP <formula formulatype="inline"> <tex Notation="TeX">$\hbox{Nb}_{3}\hbox{Sn}$</tex></formula> Quadrupoles

Wang

Ambrosio

Borgnolutti

et al. 2014

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

The U.S. LHC Accelerator Research Program has been developing Nb 3 Sn quadrupole magnets of progressively increasing performance and complexity for the High-Luminosity LHC project. The magnets are wound with Rutherford cables following the wind-and-react process. The resulting inter-strand coupling can generate strong field distortions during current ramp. The latest series of 120 mm aperture magnets (HQ) are designed and built for high field quality, offering an opportunity for detailed studies of these effects. Magnetic measurements of firstgeneration HQ magnets showed strong ramp-rate dependence. A stainless-steel core was introduced for the second generation of magnet coils to control the inter-strand coupling currents and the resulting dynamic multipoles. We report the observed dynamic effects and compare with calculations taking into account the coil geometry and cross-contact resistance in the Rutherford cable. In particular, the dependence of field quality on width and position of the stainless steel core is discussed.

show abstract

“…They will be used primarily to derive feedback for the dipole correction circuits during persistent current decay and snap-back. Work has continued on beam feedback for orbit, tune and chromaticity [5]. An overall bandwidth of 1 Hz will be necessary and deterministic control will be provided using commercially available field busses…”

Section: Power Converter Performancementioning

confidence: 99%

Update on the powering strategy of LHC

Proudlock

Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)

Self Cite

View full text Add to dashboard Cite

Over the last two years the powering strategy of the Large Hadron Collider (LHC) has undergone a considerable evolution. This was not only motivated by new requirements but more importantly by a quest to reduce costs and improve operational reliability and flexibility. In order to achieve this, despite an increase in complexity, novel modifications to the strategy and hardware have been proposed both on the warm and cold sides of the machine. During this process the requirements of the accelerator physics have been clarified and met while working within the boundary conditions imposed by the utilisation of the existing CERN infrastructure. After a brief review of the present powering strategy which needs to produce and supply 2MA dc in 1800 circuits, more detailed descriptions will be given of the changes implemented in order to achieve a more rational overall system. Some performance issues of the powering system will also be discussed.

show abstract

Dynamic effects and their control at the LHC

Cited by 5 publications

References 4 publications

The Multipoles Factory: an element of the LHC control

The Multipoles Factory: an element of the LHC control

Multipoles Induced by Inter-Strand Coupling Currents in LARP <formula formulatype="inline"> <tex Notation="TeX">$\hbox{Nb}_{3}\hbox{Sn}$</tex></formula> Quadrupoles

Update on the powering strategy of LHC

Contact Info

Product

Resources

About