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tuning_the_s800_xdt [2015/10/26 14:04] pereira |
tuning_the_s800_xdt [2015/10/26 14:09] pereira [Coincidences] |
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- | ===== Reaction Setting ===== | ||
- | ==== Setting up Reaction Settings ==== | + | |
+ | |||
+ | |||
+ | |||
+ | ====== Dispersion Matching tuning ====== | ||
+ | |||
+ | In the dispersion-matching optics, the S800 focal point is achromatic, i.e. the position of the beam in the dispersive direction does not depend on the momentum. As a consequence, | ||
+ | |||
+ | Charge-exchange experiments require typically this optics. In some cases, the beam used is < | ||
+ | |||
+ | * Set trigger to “s800 trigger” | ||
+ | * Ensure that the **[[s800 daq tools# | ||
+ | * Under trigger tab select **s800 trigger** (which is E1 up by definition) | ||
+ | * Deselect experiment trigger | ||
+ | * SAVE TO FILE | ||
+ | * Stop and start **[[s800 daq tools#Run Control Window|RunControl]]** to assert new trigger condition | ||
+ | |||
+ | * Select **[[s800 SpecTcl|Spectcl]]** window **S800_DISPMATCH.win** | ||
+ | | ||
+ | |||
+ | * We need to start checking the spectra showing the correlations between angle and position in both dispersive and non-dispersive directions. We typically use the spectrum **CRDC1.XG_CRDC1.TAC** for the non-dispersive direction, and **S800.FP.TRACK.XFP_TRACK.AFP** for the dispersive direction | ||
+ | | ||
+ | * The parabolas seen in the above spectra correspond to reactions with H in the target. The blurred lines on the right of the parabolas correspond to reaction with C. It is hard to see clearly this lines, so we need to make several gates | ||
+ | * Open spectrum **E1.DE_TOF.RF** and define a gate around < | ||
+ | | ||
+ | * This gate is used to fill spectra **S800.FP.TRACK.XFP_TRACK.AFP!FOI** and **CRDC1.XG_CRDC1.TAC!FOI**. As can be seen in the figures below, this gate " | ||
+ | | ||
+ | * Define rectangular gates in this spectra, making sure that it is narrow enough to select a vertical section of the parabolas, but wide enough to get enough statistics. Call them **afp** (in spectrum **CRDC1.XG_CRDC1.TAC!FOI**) and **bfp** (in spectrum **S800.FP.TRACK.XFP_TRACK.AFP!FOI**). After applying these new gates, the kinematics spectra are very clean | ||
+ | {{: | ||
+ | * The pre-defined gate **allgates** is made by the AND condition of all the gates defined above (**foi**, **afp**, and **bfp**). This gate is used to fill the spectrum **CRDC1.XG!FOI-AFP-BFP**, | ||
+ | | ||
+ | * The leftmost peak corresponds to reactions with H. The central peak are reaction with C. The goal of the tweak is to make these peaks as narrow as possible | ||
+ | * Open the NCS application **QtKM** in the Applications Menu. Open file **BLSetup_A1900.gkm**. The magnetic elements that are typically tweaked with the knob box seating on the left side of u6pc5 are **I232TA**, **I236TC**, and **I245TC** which can be found on page **S800 BLine+Spectrograph**. Other elements used to improve the focusing in the object point, and the transmission are **I172QA** and **I174QB**. The goal of the dispersion-matching tuning is to find a compromise between transmission and resolution. | ||
+ | | ||
+ | * The two figures below show the spectrum **CRDC1.XG!FOI-AFP-BFP** before (top) and after (bottom) the dispersion-matching tuning for a typical experiment. Be aware that the width given by SpecTcl for the selected peak is not too reliable. It is more convenient to do a real gaussian fit. Unfortunatelly this is not an option included in the current version of SpecTcl. That's why some device physicists prefer SpecTk for this type of tuning | ||
+ | {{: | ||
+ | |||
+ | |||
+ | ====== Reaction Setting ====== | ||
+ | |||
+ | ===== Setting up Reaction Settings | ||
* Calculating reaction setting | * Calculating reaction setting | ||
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* Move blocker, decrease attenuator, repeat | * Move blocker, decrease attenuator, repeat | ||
- | ==== Coincidences ==== | + | |
+ | |||
+ | |||
+ | |||
+ | ===== Coincidences | ||
* Overview | * Overview | ||
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- | ===== Follow-up ===== | + | |
+ | |||
+ | ====== Follow-up | ||
* Before leaving beam with experimenters | * Before leaving beam with experimenters | ||
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Starting logging | Starting logging | ||
- | |||
- | |||
- | ====== Dispersion Matching tuning ====== | ||
- | |||
- | In the dispersion-matching optics, the S800 focal point is achromatic, i.e. the position of the beam in the dispersive direction does not depend on the momentum. As a consequence, | ||
- | |||
- | Charge-exchange experiments require typically this optics. In some cases, the beam used is < | ||
- | |||
- | * Set trigger to “s800 trigger” | ||
- | * Ensure that the **[[s800 daq tools# | ||
- | * Under trigger tab select **s800 trigger** (which is E1 up by definition) | ||
- | * Deselect experiment trigger | ||
- | * SAVE TO FILE | ||
- | * Stop and start **[[s800 daq tools#Run Control Window|RunControl]]** to assert new trigger condition | ||
- | |||
- | * Select **[[s800 SpecTcl|Spectcl]]** window **S800_DISPMATCH.win** | ||
- | | ||
- | |||
- | * We need to start checking the spectra showing the correlations between angle and position in both dispersive and non-dispersive directions. We typically use the spectrum **CRDC1.XG_CRDC1.TAC** for the non-dispersive direction, and **S800.FP.TRACK.XFP_TRACK.AFP** for the dispersive direction | ||
- | | ||
- | * The parabolas seen in the above spectra correspond to reactions with H in the target. The blurred lines on the right of the parabolas correspond to reaction with C. It is hard to see clearly this lines, so we need to make several gates | ||
- | * Open spectrum **E1.DE_TOF.RF** and define a gate around < | ||
- | | ||
- | * This gate is used to fill spectra **S800.FP.TRACK.XFP_TRACK.AFP!FOI** and **CRDC1.XG_CRDC1.TAC!FOI**. As can be seen in the figures below, this gate " | ||
- | | ||
- | * Define rectangular gates in this spectra, making sure that it is narrow enough to select a vertical section of the parabolas, but wide enough to get enough statistics. Call them **afp** (in spectrum **CRDC1.XG_CRDC1.TAC!FOI**) and **bfp** (in spectrum **S800.FP.TRACK.XFP_TRACK.AFP!FOI**). After applying these new gates, the kinematics spectra are very clean | ||
- | {{: | ||
- | * The pre-defined gate **allgates** is made by the AND condition of all the gates defined above (**foi**, **afp**, and **bfp**). This gate is used to fill the spectrum **CRDC1.XG!FOI-AFP-BFP**, | ||
- | | ||
- | * The leftmost peak corresponds to reactions with H. The central peak are reaction with C. The goal of the tweak is to make these peaks as narrow as possible | ||
- | * Open the NCS application **QtKM** in the Applications Menu. Open file **BLSetup_A1900.gkm**. The magnetic elements that are typically tweaked with the knob box seating on the left side of u6pc5 are **I232TA**, **I236TC**, and **I245TC** which can be found on page **S800 BLine+Spectrograph**. Other elements used to improve the focusing in the object point, and the transmission are **I172QA** and **I174QB**. The goal of the dispersion-matching tuning is to find a compromise between transmission and resolution. | ||
- | | ||
- | * The two figures below show the spectrum **CRDC1.XG!FOI-AFP-BFP** before (top) and after (bottom) the dispersion-matching tuning for a typical experiment. Be aware that the width given by SpecTcl for the selected peak is not too reliable. It is more convenient to do a real gaussian fit. Unfortunatelly this is not an option included in the current version of SpecTcl. That's why some device physicists prefer SpecTk for this type of tuning | ||
- | {{: | ||