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+ | ====== Technical Aspects of the S800 ====== | ||
+ | ===== Technical Introduction ===== | ||
+ | ==== General ==== | ||
+ | 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/ | ||
- | **The S800 spectrograph** | + | {{: |
+ | |||
+ | ==== 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. | ||
+ | |||
+ | |||
+ | ==== Spectrograph ==== | ||
+ | The spectrograph | ||
+ | |||
+ | |||
+ | |||
+ | ^ Momentum Resolution (p/ | ||
+ | ^ Momentum Acceptance | ||
+ | ^ Angle Resolution | ||
+ | ^ Solid Angle Acceptance | ||
+ | ^ Momentum Dispersion (x/ | ||
+ | ^ Angle Dispersion (y/b) | no colspan this time | | ||
+ | ^ Magnification(x/ | ||
+ | ^ Focal Plane Size (x × y) | no colspan this time | | ||
+ | ^ Maximum Rigidity | ||
+ | ^ Detector Position Resolution (x)| no colspan this time | | ||
+ | |||
+ | |||
+ | |||
+ | |||
+ | ====== Headline ====== | ||
+ | ====== Headline ====== | ||
+ | |||
+ | ====== Headline ====== | ||
+ | ====== Level 1 Headline ====== | ||
+ | ===== Level 2 Headline ===== | ||
+ | ==== Level 3 Headline ==== | ||
+ | === Level 4 Headline === | ||
+ | == Level 5 Headline == | ||
+ | |||
+ | ---- | ||
+ | ∑ | ||
+ | * Unordered List Item | ||
+ | * * Unordered List Item | ||
+ | * * Unordered List Item | ||
+ | * | ||
+ | * Technical Introduction | ||
- | * Brief technical details | ||
- | * Precise angular and momentum measurements | ||
- | * High acceptance to cover large emittances of RNB | ||
- | * Layout / magnets | ||
- | * Figures of merit | ||
- | * Modes of operation | ||
- | * How are angle and momentum measured? | ||
* Ion optics | * Ion optics | ||
* Detectors | * Detectors | ||
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* Panel Mates | * Panel Mates | ||
* DAQ | * DAQ | ||
- | * | ||
* Experiment types | * Experiment types | ||
* Coulex | * Coulex | ||
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- | THE S800 SPECTROGRAPH | + | **THE S800 SPECTROGRAPH** |
+ | |||
+ | |||
+ | |||
INTRODUCTION | INTRODUCTION | ||
+ | |||
+ | |||
The S800 [xx] 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 [xx]. It was designed for high-precision measurements of scattering angles (ΔΘ=2) and momentum (p/ | The S800 [xx] 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 [xx]. It was designed for high-precision measurements of scattering angles (ΔΘ=2) and momentum (p/ | ||
+ | |||
The analysis line can be used in two different modes. In the focus mode, the maximum momentum acceptance is achieved (±2%) by making the analysis line achromatic (with maximum dispersion at the intermediate image plane).In this mode the position of the fragment at the spectrograph focal plane is sensitive to the momentum of the beam impinging on the target. Consequently | The analysis line can be used in two different modes. In the focus mode, the maximum momentum acceptance is achieved (±2%) by making the analysis line achromatic (with maximum dispersion at the intermediate image plane).In this mode the position of the fragment at the spectrograph focal plane is sensitive to the momentum of the beam impinging on the target. Consequently | ||
+ | |||
In the S800, the angles, positions and energy of the fragments in the reaction target are determined from the angles and positions measured at the focal plane. | In the S800, the angles, positions and energy of the fragments in the reaction target are determined from the angles and positions measured at the focal plane. | ||
ION OPTICS | ION OPTICS | ||
+ | |||
The optical coordinates used in the S800 are described in relation to a central trajectory passing through the center of the S800 magnets, and with the reference momentum given by p_0=qBρ_0 | The optical coordinates used in the S800 are described in relation to a central trajectory passing through the center of the S800 magnets, and with the reference momentum given by p_0=qBρ_0 | ||
DETECTORS | DETECTORS | ||
+ | |||
The standard detection system of the S800 includes a plastic scintillator at the object station; two tracking detector at the detector station in the Intermediate Image plane; a pair of cathode readout drift chambers (CRDC) located about 1 m apart; a multi-segmented ion chamber, and four large plastic scintillators of thicknesses 3 mm, 5 cm, 10 cm and 20 cm, respectively. | The standard detection system of the S800 includes a plastic scintillator at the object station; two tracking detector at the detector station in the Intermediate Image plane; a pair of cathode readout drift chambers (CRDC) located about 1 m apart; a multi-segmented ion chamber, and four large plastic scintillators of thicknesses 3 mm, 5 cm, 10 cm and 20 cm, respectively. | ||
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Cathode Readout Drift Chambers (CRDC) | Cathode Readout Drift Chambers (CRDC) | ||
+ | |||
Two Cathode Readout Drift Chamber (CRDC) are used to measure the transversal positions and angles in the focal plane. The first detector (CRDC1) is located at the nominal optical focal plane, and it is separated 1 m from the second downstream detector (CRDC2). | Two Cathode Readout Drift Chamber (CRDC) are used to measure the transversal positions and angles in the focal plane. The first detector (CRDC1) is located at the nominal optical focal plane, and it is separated 1 m from the second downstream detector (CRDC2). | ||
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Ionization Chamber | Ionization Chamber | ||
+ | |||
An ionization chamber downstream of both CRDCs is used to identify the Z number of the transmitted nuclei from their energy loss. The detector has an active volume of xxx cm x xxx cm x xxx cm and is filled with P10 gas at a typical pressure of 300 torr, although this value can be increased up to 600 torr for light nuclei. A technical layout of the detector is shown in Fig. Table xxx lists some of the technical specifications. The detector consists of 16 stacked-parallel plate ion chambers with narrow anode-cathode gaps, placed along the detector’s central axis. Each anode is sandwiched by two cathodes foils made of aluminum evaporated mylar. | An ionization chamber downstream of both CRDCs is used to identify the Z number of the transmitted nuclei from their energy loss. The detector has an active volume of xxx cm x xxx cm x xxx cm and is filled with P10 gas at a typical pressure of 300 torr, although this value can be increased up to 600 torr for light nuclei. A technical layout of the detector is shown in Fig. Table xxx lists some of the technical specifications. The detector consists of 16 stacked-parallel plate ion chambers with narrow anode-cathode gaps, placed along the detector’s central axis. Each anode is sandwiched by two cathodes foils made of aluminum evaporated mylar. | ||
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Tracking Parallel Plate Avalanche Counters | Tracking Parallel Plate Avalanche Counters | ||
+ | |||
Some experiments are particularly sensitive to the incoming positions and angles of the nuclei impinging on the target. Two tracking parallel plate avalanche counters (TPPAC) are installed in the intermediate image plane of the analysis line. The position and angles measured with both TPPACs are transformed into the corresponding coordinates in front of the target, using the transfer matrix of the second half of the analysis line. The analysis-line dipole magnets downstream of the intermediate image plane filter the particles produced | Some experiments are particularly sensitive to the incoming positions and angles of the nuclei impinging on the target. Two tracking parallel plate avalanche counters (TPPAC) are installed in the intermediate image plane of the analysis line. The position and angles measured with both TPPACs are transformed into the corresponding coordinates in front of the target, using the transfer matrix of the second half of the analysis line. The analysis-line dipole magnets downstream of the intermediate image plane filter the particles produced | ||
Each TPPAC has an active area of 10 cm × 10 cm and is filled with isobutane at a typical pressure of 5 torr. The detector consists of a cathode foil with a series of aluminum strips oriented in the non-dispersive direction, followed by an anode plate and a second cathode foil with the strips oriented in the dispersive direction (see Fig xxx). A total of 128 pads are connected to the strips of each cathode foil, with a pitch of 1.27 mm. | Each TPPAC has an active area of 10 cm × 10 cm and is filled with isobutane at a typical pressure of 5 torr. The detector consists of a cathode foil with a series of aluminum strips oriented in the non-dispersive direction, followed by an anode plate and a second cathode foil with the strips oriented in the dispersive direction (see Fig xxx). A total of 128 pads are connected to the strips of each cathode foil, with a pitch of 1.27 mm. |