S800 Documentation

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start [2013/09/30 21:42]
pereira 		start [2013/10/16 20:37]
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-====== Technical Aspects of the S800 ======+====== The NSCL S800 spectrograph ====== 
 +Welcome to the wiki page of the NSCL S800 spectrograph. The page provides technical information about the S800, as well as instructions to operate the S800 prior to and during an experiment. 
  
-===== Technical Introduction ===== 
  
-==== General ==== +===== Introduction ===== 
-The S800 [1] is a superconducting spectrograph used for reaction studies with high-energy radioactive beams produced at the NSCL Coupled-Cyclotron Facility (CCF) and the A1900 Separator [2]. It was designed for high-precision measurements of scattering angles (ΔΘ=2 msr) and momentum (p/Δp=2×10<sup>4</sup>), and large momentum and solid-angle acceptances (ΔΩ=20 msr, Δp/p=6%). The S800 layout is shown in Fig. 1. It consists of two parts: the analysis line and the spectrograph. +The [S800] [1] is a superconducting spectrograph used for reaction studies with high-energy radioactive beams produced at the NSCL Coupled-Cyclotron Facility (CCF) and the A1900 Separator [2]. It was designed for high-precision measurements of scattering angles (ΔΘ=2 msr) and momentum (p/Δp=2×10<sup>4</sup>), and large momentum and solid-angle acceptances (ΔΩ=20 msr, Δp/p=6%). The S800 layout is shown in Fig. 1. It consists of two parts: the analysis line and the spectrograph.  
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 {{:wiki:s800_layout.png|}} {{:wiki:s800_layout.png|}}
  
-=== Analysis Line ===+==== Analysis Line ====
  
 The analysis line extends from the object position to the target station, with a total length of 22 m. It includes four 22.5° dipoles, five quadrupole triplets, and two vertically steering magnets, assembled in two segments with configurations QQQ-H-DD-QQQ (segment 6) and QQQ-DD-H-QQQ-QQQ (segment 7) symmetrically oriented around an intermediate image plane. The maximum rigidity is 5 Tm, although it depends on the tune of the quadrupoles. The acceptances of the analysis line depends on the optical mode. The analysis line extends from the object position to the target station, with a total length of 22 m. It includes four 22.5° dipoles, five quadrupole triplets, and two vertically steering magnets, assembled in two segments with configurations QQQ-H-DD-QQQ (segment 6) and QQQ-DD-H-QQQ-QQQ (segment 7) symmetrically oriented around an intermediate image plane. The maximum rigidity is 5 Tm, although it depends on the tune of the quadrupoles. The acceptances of the analysis line depends on the optical mode.
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-=== Spectrograph ===+==== Spectrograph ====
 The spectrograph consist of two quadrupoles, a sextupole and two big dipoles assembled in a QQ-S-DD configuration (segment 8) that spans vertically from the target station to the focal plane, with a total length of 18 m. The figures of merit of the spectrograph are summarized in Table 1. Achieving the nominal angle and momentum resolution require the control of different conditions such as object size (less than 0.5 mm), target thickness, uncertainty of the incident angle on the target, intensity, and whether or not the incoming beam needs to be tracked.  The spectrograph consist of two quadrupoles, a sextupole and two big dipoles assembled in a QQ-S-DD configuration (segment 8) that spans vertically from the target station to the focal plane, with a total length of 18 m. The figures of merit of the spectrograph are summarized in Table 1. Achieving the nominal angle and momentum resolution require the control of different conditions such as object size (less than 0.5 mm), target thickness, uncertainty of the incident angle on the target, intensity, and whether or not the incoming beam needs to be tracked. 
  
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 ^ Detector Position Resolution (x)| 0.3 mm           | ^ Detector Position Resolution (x)| 0.3 mm           |
 ^ Detector Position Resolution (y)| 0.3 mm           | ^ Detector Position Resolution (y)| 0.3 mm           |
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 Some detection systems do not require a scattering chamber. In this case, the chamber will be removed and the target is slid into a pipe surrounded by the detector array. SeGA, CAESAR, GRETINA, PLUNGER, LENDA have standard frames and setups to be used with the S800. Other detector arrays would require the design and fabrication of new hardware. In this configuration a target change presently requires venting the target section and dismounting part of the hardware to access the inside of the beam pipe. This operation typically takes about 30-45 minutes.  Some detection systems do not require a scattering chamber. In this case, the chamber will be removed and the target is slid into a pipe surrounded by the detector array. SeGA, CAESAR, GRETINA, PLUNGER, LENDA have standard frames and setups to be used with the S800. Other detector arrays would require the design and fabrication of new hardware. In this configuration a target change presently requires venting the target section and dismounting part of the hardware to access the inside of the beam pipe. This operation typically takes about 30-45 minutes. 
  The S800 focal plane box (see (picture) Fig. xxx) is equipped with various detectors including two position sensitive Cathode Readout Drift Chambers (CRDCs) for tracking the trajectories of the particles, a ion chamber for the measurement of energy loss, a timing scintillator  E1, and an Hodoscope for total kinetic energy measurements.  The S800 focal plane box (see (picture) Fig. xxx) is equipped with various detectors including two position sensitive Cathode Readout Drift Chambers (CRDCs) for tracking the trajectories of the particles, a ion chamber for the measurement of energy loss, a timing scintillator  E1, and an Hodoscope for total kinetic energy measurements.
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 === Spectrograph Sextupole === === Spectrograph Sextupole ===
 The only high-order magnet included in the S800 is a sextupole coil  installed around the bore tube of Q2. The purpose of this element is to correct the broadening of the beam at the focal plane due to the dominant (x|2) 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 Q2. The purpose of this element is to correct the broadening of the beam at the focal plane due to the dominant (x|2) 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. 
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start.txt · Last modified: 2024/01/02 12:45 by pereira

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