Gunnar Fernqvist

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Power converters in the accelerator context are often required to deliver a performance that is unusual in an industrial context. This paper deals with some of the important aspects of high-precision output voltage and current control and in particular the current measurement transducers and their application.
The large hadron collider is CERN’s next particle accelerator project, scheduled for commissioning in 2005. The project requires accurate current measurements above 10 kA. Calibration heads have been developed in collaboration with industry to work up to 24 kA with a relative measurement uncertainty of 10 . This paper describes the design and verification(More)
The Large Hadron Collider (LHC) is CERN’s next particle accelerator project, scheduled for commissioning in 2005. The project requires accurate current measurements above 10 kA. Calibration heads have been developed in collaboration with industry to work up to 24 kA at sub-ppm accuracy. The paper describes the design and verification. Presented at the(More)
A new dc current reference standard has been developed for high-current power converter calibration in the large hadron collider (LHC) project at the European Organization for Nuclear Research (CERN). This standard provides a near ideal 10-mA dc current with long-term drift of one part in 106 per year. The paper describes the requirements and the detailed(More)
LHC Project Report 1046 CERN, CH-1211 Geneva 23 Switzerland CERN, Geneva, Switzerland Presented at PAC07, 22nd PAC Conference, June 25-29, 2007, Albuquerque, USA HIGH-PRECISION PERFORMANCE TESTING OF THE LHC POWER CONVERTERS M. Bastos, A. Cantone, P. Dreesen, G. Fernqvist, O. Fournier, G. Hudson, CERN, Geneva, Switzerland Abstract The magnet power(More)
I n the Large Hadron Collider (LHC) at CERN, the powering of the main dipole and quadrupole circuits is divided into eight separate powering sub sectors due to the very high magnetic energy stored in these circuits and to protection constraints of the superconducting magnets [1]. As a consequence, individual sector currents must be controlled with very high(More)
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