tuning_the_s800_xdt
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tuning_the_s800_xdt [2015/10/26 14:07] pereira [Setting up Reaction Settings] |
tuning_the_s800_xdt [2015/10/27 14:24] pereira [Setting up Reaction Settings] |
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| * Adjust MCFD threshold: | * Adjust MCFD threshold: | ||
| - | * Open configuration file **MCFD16.tcl** in **/user/s800/ | + | * Using the [[s800 daq tools# |
| * The OBJ signal feeding this module is not patched out to data U6 | * The OBJ signal feeding this module is not patched out to data U6 | ||
| - | * The OBJ signal from MCFD-16 module goes to the Mesytec | + | * The OBJ signal from MCFD module goes to the Mesytec |
| * Make sure that the threshold of the XFP MCFD channel is reasonable. Rates in scaler channels XFP.Scint and XFP.MCFD.Scint should be comparable | * Make sure that the threshold of the XFP MCFD channel is reasonable. Rates in scaler channels XFP.Scint and XFP.MCFD.Scint should be comparable | ||
| * Adjust MCFD OBJ threshold looking at scalers. The ratio of OBJ to XFP scaler rates (channels OBJ.MCFD.Scint and XFP.MCFD.Scint) should reflect the transmission of the cocktail beam | * Adjust MCFD OBJ threshold looking at scalers. The ratio of OBJ to XFP scaler rates (channels OBJ.MCFD.Scint and XFP.MCFD.Scint) should reflect the transmission of the cocktail beam | ||
| Line 214: | Line 214: | ||
| ==== Analysis line classic PPAC setup (Focus optics only) ==== | ==== Analysis line classic PPAC setup (Focus optics only) ==== | ||
| + | **THIS SECTION IS STILL IN PROGRESS** | ||
| * " | * " | ||
| Line 237: | Line 238: | ||
| ==== Setting Optimization ==== | ==== Setting Optimization ==== | ||
| - | |||
| - | === Focused optics === | ||
| * Expectations for A1900 FP to S800 FP transmission | * Expectations for A1900 FP to S800 FP transmission | ||
| Line 248: | Line 247: | ||
| * Want to balance losses between S800 analysis line and Transfer Hall (the S800 analysis line is typically slightly worse) | * Want to balance losses between S800 analysis line and Transfer Hall (the S800 analysis line is typically slightly worse) | ||
| * Best diagnostic is scalers from S800 FP, object scintillator and XF scintillator | * Best diagnostic is scalers from S800 FP, object scintillator and XF scintillator | ||
| - | * Tweak y-quads (while watching scalers) in front of dipole gaps (this works both for Transfer Hall and analysis line); choose elements that have biggest effect with smallest ratio change | + | * Using the knob box and the NCS application **QtKM** (file **BLSetup_A1900.gkm**), |
| * Document optimized transmission with another run to disk to measure rate of fragment of interest at S800 FP | * Document optimized transmission with another run to disk to measure rate of fragment of interest at S800 FP | ||
| Line 254: | Line 253: | ||
| - | ===== Reaction Setting ===== | ||
| - | ==== Coincidences ==== | + | |
| + | |||
| + | |||
| + | ====== Dispersion Matching Mode ====== | ||
| + | |||
| + | 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 sitting 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 | ||
| + | * Center unreacted beam at S800 FP | ||
| + | * Adjust spectrograph Brho to center beam at S800 FP | ||
| + | * Requirements for a beam to be “Centered” | ||
| + | * Spectrograph dipoles matched | ||
| + | * Beam position within about 1 cm of center as judges by 0 point on crdc1x spectrum or on track.xfp spectrum | ||
| + | * Record run to disk to document centered unreacted beam setting | ||
| + | * Calculate reaction setting using “effective” beam energy and the nominal target thickness | ||
| + | * Ideally, experimenters should be the ones making this calculation | ||
| + | * This approach assumes that the target thickness is known | ||
| + | |||
| + | |||
| + | * Reaction setting to FP | ||
| + | * Start with Attenuator setting of unreacted beam and step up in intensity | ||
| + | * Looking at **CRDC1.RAWS** and/or **CRDC2.RAWS** SpecTcl spectra (shown in **S800_CRDCS.WIN**), | ||
| + | * Expected " | ||
| + | * Expect to see unreacted beam if reaction setting is within +/- 3% of unreacted beam setting | ||
| + | * Should have to move only one of the two blockers unless charge states are present | ||
| + | * Try to cut only as much as necessary; depends on | ||
| + | * What rate limits allow | ||
| + | * What experimenters want (e.g., if they want singles, the cut has to be more restrictive to limit acquisition deadtime) | ||
| + | * Move blocker, decrease attenuator, repeat | ||
| + | |||
| + | |||
| + | |||
| + | |||
| + | |||
| + | ===== Coincidences | ||
| * Overview | * Overview | ||
| Line 267: | Line 333: | ||
| * Probably smaller typical S800 delay needed for HiRA | * Probably smaller typical S800 delay needed for HiRA | ||
| * An example of experiments where auxiliary detectors are not used and, thus, setting up coincidence timing is not an issue are the experiments with tritons run by the charge exchange group | * An example of experiments where auxiliary detectors are not used and, thus, setting up coincidence timing is not an issue are the experiments with tritons run by the charge exchange group | ||
| - | * It is not clear whether coincidence setup gets logged as “XDT” or “EXR” | + | |
| * Choice of setting to be used for coincidence timing setup | * Choice of setting to be used for coincidence timing setup | ||
| * The reaction of interest for the experiment can be used to setup coincidences only if the rate of coincidences is high enough | * The reaction of interest for the experiment can be used to setup coincidences only if the rate of coincidences is high enough | ||
| Line 301: | Line 366: | ||
| - | ===== Follow-up ===== | + | |
| + | |||
| + | ====== Follow-up | ||
| * Before leaving beam with experimenters | * Before leaving beam with experimenters | ||
| Line 341: | Line 408: | ||
| 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 | ||
| - | {{: | ||
tuning_the_s800_xdt.txt · Last modified: 2023/09/22 15:15 by swartzj
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