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+ | ====== 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 Aspects of the S800 ===== | ||
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+ | * [[Introduction]] | ||
+ | * [[Stations]] | ||
+ | * [[Magnets]] | ||
+ | * [[Modes of Operation]] | ||
+ | * [[Determination of Angles and Momentum]] | ||
+ | * [[Detectors]] | ||
+ | * [[https:// | ||
+ | * Software | ||
+ | * Coupled Detectors/ | ||
+ | * Types of Experiments | ||
+ | |||
+ | ===== Operation of the S800 ===== | ||
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+ | ==== Magnets ==== | ||
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+ | === 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, | ||
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+ | === 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. | ||
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+ | ====== 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 | ||
- | **The S800 spectrograph | ||
- | * Brief technical details | ||
- | * Unordered List ItemPrecise 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 | ||
- | | + | |
- | * TPPACs | + | * TPPACs |
- | * CRDCs | + | * CRDCs |
- | * IC | + | * IC |
- | * FPSCI | + | * FPSCI |
- | * Hodoscope | + | * Hodoscope |
* Electronics | * Electronics | ||
- | | + | |
- | * Triggers | + | * Triggers |
- | * Signal optimization | + | * Signal optimization |
* Software | * Software | ||
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- | * Barney | + | * Barney |
- | * Bklq | + | * Bklq |
- | * Panel Mates | + | * Panel Mates |
* DAQ | * DAQ | ||
- | * | ||
* Experiment types | * Experiment types | ||
- | | + | |
- | * CE | + | * CE |
- | * Knockout | + | * Knockout |
- | * ... | + | * ... |
* Supported detectors (Background suppression): | * Supported detectors (Background suppression): | ||
- | | + | |
- | * CAESAR | + | * CAESAR |
- | * SeGA | + | * SeGA |
- | * GRETINA | + | * GRETINA |
- | * Neutron | + | * Neutron |
- | * LENDA | + | * LENDA |
- | * Charge particle | + | * Charge particle |
- | * HiRA | + | * HiRA |
- | * | + | |
- | Organization of responsibilities: | + | * Organization of responsibilities: |
- | Planning an experiment with the S800 | + | |
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- | THE S800 SPECTROGRAPH | + | **THE S800 SPECTROGRAPH** |
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INTRODUCTION | INTRODUCTION | ||
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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/ | ||
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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 | ||
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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 | ||
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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 | ||
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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) | ||
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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 | ||
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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 | ||
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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. |