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modes_of_operation [2016/01/19 12:31] pereira [Focus Mode] |
modes_of_operation [2016/01/19 12:35] pereira [Dispersion-matching Mode] |
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{{:wiki:focused.png?550|Mask pattern measure in CRDC2 during a reaction setting.}} | {{:wiki:focused.png?750|Ion optics diagram for S800 in focus mode.}} |
===== Dispersion-matching Mode ===== | ===== Dispersion-matching Mode ===== |
In the dispersion-matching mode the whole system ([[Introduction#Analysis Line|analysis line]] + [[Introduction#Spectrograph|spectrograph]]) is achromatic in the focal plane (see [[Fig. xxx]]). The analysis line has a 2D focus (in the dispersive //x// and non-dispersive //y// directions ) in the target point and has a high dispersion of about 11 cm/%, limiting the momentum acceptance to ±0.5%. The intermediate image plane has also a 2D focus and a dispersion of 1.5 cm/%. This mode provides the highest possible energy resolution (1 part in 5000 for a 1-mm wide beam spot), since it does not require momentum tracking. | In the dispersion-matching mode the whole system ([[Introduction#Analysis Line|analysis line]] + [[Introduction#Spectrograph|spectrograph]]) is achromatic in the focal plane (see figure below). The analysis line has a 2D focus (in the dispersive //x// and non-dispersive //y// directions ) in the target point and has a high dispersion of about 11 cm/%, limiting the momentum acceptance to ±0.5%. The intermediate image plane has also a 2D focus and a dispersion of 1.5 cm/%. This mode provides the highest possible energy resolution (1 part in 5000 for a 1-mm wide beam spot), since it does not require momentum tracking. |
Please, be aware that in this configuration, two of the quadrupoles before and after the intermediate image plane (I210TB and 217TB) are strongly focusing, thus requiring unusually higher currents than for a setting in focus mode running at the same rigidity. This may represent a restriction to consider when planning an experiment at high magnetic rigidities (e.g. using a <sup>3</sup>H secondary beam). | Please, be aware that in this configuration, two of the quadrupoles before and after the intermediate image plane (I210TB and 217TB) are strongly focusing, thus requiring unusually higher currents than for a setting in focus mode running at the same rigidity. This may represent a restriction to consider when planning an experiment at high magnetic rigidities (e.g. using a <sup>3</sup>H secondary beam). |
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| {{:wiki:matched60x40.png?750|Ion optics diagram for S800 in dispersion-matching mode.}} |
===== Monochromatic Mode ===== | ===== Monochromatic Mode ===== |
__The monochromatic mode is still in development stage__. The motivation is the production of low-energy (5-10 MeV) secondary beams from a high-energy fragmentation beam. The implementation of this mode requires the use of a mono-energetic wedged installed in the intermediate image station. The wedge profile must be built on a case-by-case basis, considering the specific energy and nuclei in the experiment. | __The monochromatic mode is still in development stage__. The motivation is the production of low-energy (5-10 MeV) secondary beams from a high-energy fragmentation beam. The implementation of this mode requires the use of a mono-energetic wedged installed in the intermediate image station. The wedge profile must be built on a case-by-case basis, considering the specific energy and nuclei in the experiment. |
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