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+ | 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 | + | ===== Technical Aspects of the S800 ===== |
- | The S800 [1] is a superconducting spectrograph used for reaction studies with high-energy radioactive | + | |
+ | * [[Introduction]] | ||
+ | * Stations | ||
+ | * Magnets | ||
+ | * Modes of Operation | ||
+ | * Determination of Angles and Momentum | ||
+ | * Detectors | ||
+ | * Electronics | ||
+ | * Software | ||
+ | * Data Acquisition | ||
+ | * Coupled Detectors/ | ||
+ | * Types of Experiments | ||
+ | |||
+ | ===== Operation of the S800 ===== | ||
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+ | ==== S800 Stations ==== | ||
+ | The S800 includes several detector stations: | ||
+ | |||
+ | The intermediate image box (see (picture) Fig. xxx) is equipped with two Tracking Parallel Plate Avalanche Counters (TPPACs) . | ||
+ | |||
+ | The standard configuration of the S800 used to employ a scattering chamber (see (picture) Fig. xxx) that contains a ladder for holding the targets. This ladder is mounted on a drive that allowed for continuous rotation as well as vertical translation for the fine adjustment of the target position | ||
+ | |||
+ | A much larger scattering chamber | ||
+ | |||
+ | As mentioned before, the scattering chamber is equipped with drives that can accommodate any kind of tracking detector (with a small adaption). Standard PPAC detectors (limited to 1 kHz count rate) can be installed at those locations. However, one should keep in mind that reaction products stemming from interaction of the beam with the detectors pose a possible contamination of the beam and require " | ||
+ | |||
+ | 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 | ||
+ | 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 | ||
{{: | {{: | ||
- | === 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. | ||
+ | ==== Magnets ==== | ||
+ | |||
+ | === Spectrograph Dipoles === | ||
+ | Each S800 dipole [3] 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. 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 | ||
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+ | |||
+ | === Spectrograph Quadrupole Doublet === | ||
+ | In order to maximize the acceptance of the spectrograph, | ||
- | === Spectrograph === | ||
- | The spectrograph consist of two quadrupoles, | ||
+ | === 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. | ||
- | ^ Momentum Resolution (p/ | ||
- | ^ Momentum Acceptance | ||
- | ^ Angle Resolution | ||
- | ^ Solid Angle Acceptance | ||
- | ^ Momentum Dispersion (x/ | ||
- | ^ Angle Dispersion (y/b) | 0.9 mm/ | ||
- | ^ Magnification(x/ | ||
- | ^ Focal Plane Size (x × y) | 55 cm ×15 cm | ||
- | ^ Maximum Rigidity | ||
- | ^ Detector Position Resolution (x)| 0.3 mm | | ||
- | ^ Detector Position Resolution (y)| 0.3 mm | | ||