Expected Harmonics (Version 1.0) in BNL-built LHC Dipoles
- Brookhaven National Lab. (BNL), Upton, NY (United States)
It is proposed to build several types of dipoles for the Large Hadron Collider (LHC) at BNL. All these dipoles require a coil inner diameter of 8 cm and will use the same coil design that was used for the RIDC arc dipoles (DRG type). The beam separations at the D4A and D4B locations are 234 mm and 194 mm respectively, which are smaller than the outer diameter (266.7 mm) of the yoke in the DRG magnets. As a result, these magnets must be built as twin-aperture magnets with redesigned yokes. Such yokes have been designed [1] employing a 550 mm x 659.2 mm oblate shape. The beam separations at the D3A and D3B magnet locations are 400 mm and 382 mm respectively. These magnets also can be built as twin-aperture magnets using yokes of the same dimensions as for the D4A and D4B magnets. However, it may be more cost effective to build these magnets as single aperture magnets, identical to the DRG magnets. As an added advantage, the horizontal size of the D4A and D4B yokes can be reduced somewhat, without giving up field quality. A preliminary design has been carried out for D4A and D4B yokes with a vertical size of 550 mm and a reduced horizontal size of 625 mm. The expected field quality for the 550 mm x 659.2 mm yoke design is given in reference [1]. This note describes the field quality expected in the DRG and 550 mm x 625 mm magnet designs under conditions of LHC operation. For the single aperture magnets which will be identical to the RIDC dipoles, the expected numbers are based entirely on measured data in DRG magnets. The presence of a second cold mass nearby as well as asyimnetric placement of the cold masses in the cryostat will result in some change in the unallowed hannonics at high fields. These effects are not included at present in the numbers for the single aperture "DRG-Like" magnets. For the twin-aperture D4A and D4B magnets, the field quality estimates are based on data in the DRG magnets, as well as numerical calculations. At present, these calculations include the effect of cross-talk between the two apertures, but do not include the effect of the cryostat.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 1119538
- Report Number(s):
- BNL-102253-2013-IR
- Country of Publication:
- United States
- Language:
- English
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