Dynamic field quality of LHC/Saclay arc quadrupole magnet prototype

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Abstract-The construction of the third second-generation main quadrupole magnet prototype for LHC has been completed at CEA/Saclay in November 2000.The magnet was tested at 1.9 K. Similarly to the two first ones, this prototype has exceeded the operating current in one training step and exhibited excellent training memory after a thermal cycle. This paper describes the quench performance and quench start localization determined by means of voltage-taps and a quench antenna system developed in collaboration with KEK.As this magnet was equipped with capacitive gauges, the stresses during cool-down and powering have been recorded and are in agreement with FE computations. The newly designed quench heaters have improved efficiency and reproducibility compared to those of the first generation.Magnetic measurements have been performed at various stages. The cold measurements show minor differences with those at room temperature and are similar to those of the two first magnets of this design.These results prove that the magnets are mechanically stable and confirm the design retained for the series production of the 400 LHC main quadrupoles.

Section: Magnetic Measurementsmentioning

confidence: 99%

Test results of the third LHC main quadrupole magnet prototype at CEA/Saclay

Simon

Gourdin

Schild

et al. 2002

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“…This allows to make a hardware bucking of about 900 for the dipole and 400 for quadrupole terms. The reproductibility is a few 10 -6 with respect to B 2 [5]. This system was compared with another system used in CEA for cold test.…”

Section: Warm Magnetic Measurementsmentioning

confidence: 99%

Construction of the new prototype of main quadrupole cold masses for the arc short straight sections of LHC

Peyrot

Rifflet²,

Simon

et al. 2000

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Each cold mass of the short straight sections in the eight LHC arcs will contain a 3.25 m long twin aperture quadrupole of a nominal gradient of 223 T/m. This magnet will be aligned in a 5.3 m long inertia tube together with auxiliary magnets on each end. On the quadrupole connection end either a pair of 38 cm long octupole or trim quadrupole magnets will be mounted, on the other end there will be combined sextupoledipole correctors with a yoke length of 1.26 m. The powering of the main quadrupoles will be assured by two pairs of copper stabilized superconducting bus-bars placed inside the cold mass next to the bus-bars for the main dipole magnets. Each of the two quadrupole apertures will be connected to its quench protection diode. The construction of three prototypes has been entrusted to the CEA/Saclay laboratory, in the frame of the special French contribution to the LHC project. The first cold mass prototype has been completed and warmmeasured for its multipole content at CEA. The second cold mass is presently under completion. The paper will review the experience with the development of the quadrupole coils and cold mass construction and gives the results of the first warm magnetic measurements. An outlook for the series manufacture of the 400 arc quadrupole magnets and their cold masses for the LHC machine will complete the report. Abstract--Each cold mass of the short straight sections in the eight LHC arcs will contain a 3.25 m long twin aperture quadrupole of a nominal gradient of 223 T/m. This magnet will be aligned in a 5.3 m long inertia tube together with auxiliary magnets on each end. On the quadrupole connection end either a pair of 38 cm long octupole or trim quadrupole magnets will be mounted, on the other end there will be combined sextupole-dipole correctors with a yoke length of 1.26 m. The powering of the main quadrupoles will be assured by two pairs of copper stabilized superconducting bus-bars placed inside the cold mass next to the bus-bars for the main dipole magnets. Each of the two quadrupole apertures will be connected to its quench protection diode. The construction of three prototypes has been entrusted to the CEA/Saclay laboratory, in the frame of the special French contribution to the LHC project. The first cold mass prototype has been completed and warm-measured for its multipole content at CEA. The second cold mass is presently under completion. The paper will review the experience with the development of the quadrupole coils and cold mass construction and gives the results of the first warm magnetic measurements. An outlook for the series manufacture of the 400 arc quadrupole magnets and their cold masses for the LHC machine will complete the report.

“…The measurements were performed at the magnet center while stopping the current ramp at each target stainless steel collar [5]. For the QCS, the influence of the magnetization of the collar, whose material is SUS-3 16LN, is estimated to be 2 .…”

Section: Current Dependence On a Multipole Fieldmentioning

confidence: 99%

Field quality measurements of spare TRISTAN insertion quadrupole magnet with yoke added

Ohuchi

Ogitsu

Ajima

et al. 1997

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One of the TRISTAN insertion quadrupole magnets was yoked and tested. The original magnet was an iron free magnet. The magnetic field measurements of the original and the yoked magnets were performed at 4.2K. The transfer functions of the original and yoked magnets were measured and compared. The multipole fields as a function of axial position and magnet current are presented for the both magnets.