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magnets [2013/12/24 09:03]
pereira [Spectrograph Dipoles]
magnets [2013/12/29 16:43] (current)
pereira [Spectrograph Dipoles]
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 ===== Spectrograph Dipoles ===== ===== Spectrograph Dipoles =====
-Each S800 dipole weights 70 Tons and has a 15 cm gap. The bending radii and angle are 2.8 m and 75°, respectively. The magnet has five main pieces: two top slabs, the inner and outer side yokes, and the pole tip assembly. The maximum current supplied to the coil is 450 A, translating into a 1.6 T maximum central magnetic field, and a maximum magnetic rigidity of about 4 Tm. [[NMR probes|NMR probes]] are installed in the flat field region to measure the absolute field setting during operation. The dipole steel has a 30° edge angle, so that particles are defocused and focused in the dispersive and non-dispersive directions, respectively. Trim coils are installed on the inner and outer radii of the dipoles to achieve a uniform field near the edges of the magnet. The operating current of the trim coils is 43.75% the value of the magnets. A liquid helium feed circuit brings liquid helium through a heat exchanger at the top of the magnet and delivers the liquid into the bottom of the coils. The helium overflowing the coils fills the dewar to provide cooling for the incoming liquid. Liquid nitrogen is supplied at the bottom of each side. A 0.25 Ω dissipative resistor with a short decay constant is connected to a coil [[protection switch]]. In case of cryogenic failure, the switch reroutes the power supplied to the circuit into the resistor. The picture below (left figure) shows the second spectrograph dipole as seen from the top level of the [[S3 vault]].+Each S800 dipole weights 70 Tons and has a 15 cm gap. The bending radii and angle are 2.8 m and 75°, respectively. The magnet has five main pieces: two top slabs, the inner and outer side yokes, and the pole tip assembly. The maximum current supplied to the coil is 450 A, translating into a 1.6 T maximum central magnetic field, and a maximum magnetic rigidity of about 4 Tm. [[NMR probes|NMR probes]] are installed in the flat field region to measure the absolute field setting during operation. The dipole steel has a 30° edge angle, so that particles are defocused and focused in the dispersive and non-dispersive directions, respectively. Trim coils are installed on the inner and outer radii of the dipoles to achieve a uniform field near the edges of the magnet. The operating current of the trim coils is 43.75% the value of the magnets. A liquid helium feed circuit brings liquid helium through a heat exchanger at the top of the magnet and delivers the liquid into the bottom of the coils. The helium overflowing the coils fills the dewar to provide cooling for the incoming liquid. Liquid nitrogen is supplied at the bottom of each side. A 0.25 Ω dissipative resistor with a short decay constant is connected to a coil [[Turning magnets on/​off#​Arming of Dump Switch|protection switch]]. In case of cryogenic failure, the switch reroutes the power supplied to the circuit into the resistor. The picture below (left figure) shows the second spectrograph dipole as seen from the top level of the [[S3 vault]].
  
 {{:​wiki:​dipole-d2.jpg?​400|Second dipole of spectrograph as seen from the top level of the S3 vault.}} {{:​wiki:​dipole-d2.jpg?​400|Second dipole of spectrograph as seen from the top level of the S3 vault.}}
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 ===== Spectrograph Sextupole ===== ===== Spectrograph Sextupole =====
-The only high-order magnet included in the S800 is a sextupole coil ((Ref. to Thesis sextupole)) ​installed around the bore tube of the second quadrupole in the [[Magnets#​Spectrograph Quadrupole Double|quadrupole-doublet]] of the spectrograph. The purpose of this element is to correct the broadening of the beam at the focal plane due to the dominant (x|b<​sup>​2</​sup>​) aberration. This defines a narrower trajectory of the beam, allowing the use of a [[beam blocker]] at the focal plane to block the unreacted beam when its magnetic rigidity is close to the tuned setting. ​+The only high-order magnet included in the S800 is a sextupole coil installed around the bore tube of the second quadrupole in the [[Magnets#​Spectrograph Quadrupole Double|quadrupole-doublet]] of the spectrograph. The purpose of this element is to correct the broadening of the beam at the focal plane due to the dominant (x|b<​sup>​2</​sup>​) aberration. This defines a narrower trajectory of the beam, allowing the use of a [[beam blocker]] at the focal plane to block the unreacted beam when its magnetic rigidity is close to the tuned setting. ​
  
  
magnets.1387893798.txt.gz · Last modified: 2013/12/24 09:03 by pereira